Microbiome Metabolome Brain Vagus Nerve Circuit in Disease and Recovery 0443191220, 9780443191220

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Microbiome Metabolome Brain Vagus Nerve Circuit in Disease and Recovery  First Edition 

Elena L. Paley  Expert Biomed, Inc., Miami, FL, United States  Stop Alzheimers Corp., Miami, FL, United States 

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Table of Contents  Cover image  Title page  Copyright  Chapter 1: Introduction: Microbial metabolite interference of protein biosyn-  thesis in neurodegenerative, neurodevelopmental, and other disorders;  microbial metabolites hijacking vagus nerve  Abstract  References  Chapter 2: COVID-19: Scientific progress  Abstract  1: Introduction: Tryptophan catabolism and tryptamine in viral infec-  tions  2: Hospital-acquired infections  3: COVID-19 and bacterial infections  4: COVID-19 in Florida  5: Possible sources of SARS-CoV-2 virus transmitting/dispersing: Leak-  age of untreated wastewater, medical procedure fecal microbiota trans-  plantation, infected during insulin administration, animals, and other  ways  6: COVID-19 and necrotizing medical conditions  References  Chapter 3: Viral-bacterial interactions in diseases  Abstract 

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1: Virus-bacteria-fungi interactions, antimicrobial resistance, immune  cross-reactivity, and autoimmunity    2: Viruses (SARS-CoV-2 and herpes simplex virus type 1) and bacteria  in Alzheimer’s disease (AD)    3: Markers for blood-brain barrier (BBB) integrity: BBB integrity in  Alzheimer’s disease    4: Viruses and bacteria in cardiovascular (CVD) and liver diseases    References    Chapter 4: Vagus nerve: Acid reflux, parietal cells, carpal tunnel syndrome,  Alzheimer’s disease, COVID-19, stroke, cancer, and other diseases    Abstract    1: Etiology and mechanisms of acid reflux development    2: Carpal tunnel syndrome (CTS), numbness or tingles, heartburn, and  overuse of mobile electronic devices    3: Vagus nerve stimulation and rehabilitation    4: Conclusions    References    Chapter 5: Vagus nerve circuit: Microbiome—tryptophan metabolites—  receptors and synapses    Abstract    1: Gut dysbiosis and vagus nerve, gastroesophageal reflux disease    2: Vagus nerve and autonomic system, Arnold’s reflex    3: Vagus nerve in traditional Chinese medicine    4: Thyroid diseases, autonomic nervous system and vagus nerve    5: Vagus nerve: Receptors and neurotransmitters including glutamate, 

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laryngopharyngeal reflux, gastroesophageal reflux and associated pul-  monary diseases    6: Vagus nerve: Myelinated and unmyelinated axons and gut microbial  tryptamine    7: Hypnosis: Vagus nerve and gut microbiome    8: Conclusions    References    Chapter 6: Glutamate and glutamate receptors in vagus nerve pathways and  in Alzheimer’s disease    Abstract    1: Glutamate, biogenic amines, and interaction with receptors    2: Glutamate and tryptamine under hypoxia and in protein biosynthesis    3: Glutamate (glutamic acid) in tRNA aminoacylation and protein  biosynthesis    4: Glutamate in vagal nerve signaling    5: Conclusions    References    Chapter 7: Aminoacyl tRNA synthetase multiple forms in autoimmune and  infectious diseases    Abstract    1: Aminoacyl-tRNA synthetases in autoimmunity and COVID-19    2: Tryptophanyl-tRNA synthetase role in bacterial, viral, and parasitic  infections    3: Tryptophanyl tRNA synthetase overexpression is procancer or anti-  cancer?  

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4: Gut microbiome metabolites biogenic amines regulate enzymatic  activities of aminoacyl-tRNA synthetases (ARS) in procancer and anti-  cancer pathways and in inflammation    5: Conclusions    References    Chapter 8: Crystalized aromatic l-amino acid decarboxylase from bacteria  Micrococcus percitreus catalyzing decarboxylation of tryptophan and l-DOPA  (Levodopa or 3,4-dihydroxy-l-phenylalanine)    Abstract    1: Tryptamine, nociceptive withdrawal reflex, and vagus nerve   2: Purified and crystalized aromatic l-amino acid decarboxylase from  Micrococcus percitreus    3: Bacteria Micrococcaceae in human    4: l-DOPA and dopamine in Parkinson’s disease (PD)    5: Other bacterial tyrosine decarboxylases    6: Conclusions    References    Chapter 9: Health effects of elevated CO levels, sparkling mineral water,  2 seltzer carbonated water    Abstract    1: Carbon dioxide and carbonation           

2: Effects of CO2 in human are dose-dependent, wearing face masks  3: CO and panic attack  2 4: CO2-dependent bacteria  5: CO and vagal nerve  2

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6: Conclusions    References    Chapter 10: Microbial antigens, allergies, and antibodies to microbial aller-  gens: Significance of preexisting antibodies and stress for vaccination    Abstract    1: Allergies and infections    2: Prevalence of allergy    3: Preexisting antibodies    4: Stress and hypnosis in health and disease    5: Conclusions    References    Chapter 11: Smell and taste identification deficits in disease    Abstract    1: Vagus nerve: Olfactory and gustatory systems    2: Smell and taste disorders before COVID-19 era    3: COVID-19 and loss of smell and taste    4: Odor identification deficits in Alzheimer’s disease and aging    5: Allergies and olfactory dysfunction    6: Olfaction and gustation connection    7: Allergies and viral infections    8: Trace amine-associated receptors (TAARs) in organs with vagus  nerve innervation and modulation    9: Conclusion    References  7

Chapter 12: Microorganisms producing biogenic amines: From food to  human body   Abstract    1: Sausages, different cheese varieties, honey, yogurt    2: Fungal pathogen Fusarium graminearum: From bread wheat  pathogen to human clinical case    References    Chapter 13: Human genome or human microbiome genes: Which one is  more important for human health and intellectual abilities?    Abstract    1: From old dogma to human microbiome prior to birth    2: Tyramine inhibits tyrosine hydroxylase in intact tissues    3: Tyramine and blood-brain barrier (BBB)    4: What is the causative factor/s of the BBB subtle disruption in Parkin-  son’s disease (PD)?    5: Biogenic amines (trace amines): Metabolic changes in Parkinson’s  disease    6: Humans possess human and microbial genes    7: Necrotizing enterocolitis, preterm birth, neurodevelopment, and  vagus nerve    8: Conclusions    References    Chapter 14: Microorganisms used in agriculture, consumed from envi-  ronment and associated with the edible raw fruits, vegetables, herbs,  sprouts, and mushrooms    Abstract    8

1: Plant microbiome    2: Microorganisms in herbs    3: Microorganisms in fruits, vegetables, and sprouts    4: Microorganisms in edible mushrooms    5: Microorganisms in agricultural practice    6: Conclusions    References    Chapter 15: Molecular and cell aggregation: Biogenic amines, proteins,  platelets, and microbial pathogens    Abstract    1: Tryptamine self-assembly with its metabolite in twofold helix    2: Biogenic amines in protein aggregation    3: Aggregation of human blood plasma platelets by tryptamine and  other compounds    4: Aggregation of microbial pathogens    5: Tryptamine and airborne isocyanates    6: Conclusion    References    Chapter 16: Colonic diverticular disease as a risk factor for neurode-  generative and associated diseases    Abstract    1: Diverticular disease: Picture of the disease    2: Medical conditions and diseases associated with diverticulosis and  diverticulitis (diverticular disease)   

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3: Diverticular disease and vagal atrial fibrillation    4: Diverticular disease, colorectal cancer (CRC), cancer stem cells and  role of tryptamine in “eat me” signal    5: Conclusions    References    Chapter 17: Alzheimer’s disease, dementia, aging, and COVID-19    Abstract    1: Case series    2: Gut microbial tryptamine, serum albumin, SARS-CoV-2, and neu-  rodegeneration    3: Polyamines in viral infection and Alzheimer’s disease    4: Gut microbiota, COVID-19, dementia, and biogenic amines    5: Tryptamine in viral infection    6: Meningitis and other diseases masquerading as Alzheimer's disease  (misdiagnosed patients)    7: Conclusions    References    Chapter 18: Existing vaccines and new and old tools    Abstract    1: General concepts of vaccination    2: Antibacterial vaccines    3: Antiviral vaccines    4: Antiparasite vaccines    5: Antiprotozoal vaccines    10

6: Antifungal vaccine    7: New antiinfectious approaches: Fight with mosquito-borne diseases    8: Targeting aminoacyl-tRNA synthetases: Antimicrobial development    9: Beneficial therapeutic property of ethnomedical extracts used in folk  medicine    10: Conclusions    References    Chapter 19: Serotonin syndrome in neurodegenerative diseases and COVID-  19: Mechanisms and consequences of intestinal infection    Abstract    1: Tryptamine-induced serotonin syndrome and vagus nerve    2: Mechanisms of tryptamine-induced serotonin syndrome    3: Serotonin syndrome cases and neurodegenerative diseases    4: Serotonin syndrome cases and COVID-19    5: Conclusions    References    Chapter 20: Circulating cell-free mitochondria and membrane vesicles    Abstract    1: Circulating cell-free mitochondria    2: Cell-free extracellular membrane vesicles    3: Cell-free mitochondrial DNA    4: Conclusions    References    Chapter 21: Protein synthesis inhibition in neuronal activities  11

Abstract    1: Axonal transport, memory consolidation, neurite outgrowth    2: Mutations of genes encoding aminoacyl-tRNA synthetases and  tRNAs    3: Beta-N-methylamino-l-alanine (BMAA)    4: Vagus nerve: Dietary protein, amino acids, and high-fat high-sugar  diet    5: Conclusions    References    Chapter 22: Rosacea and associated medical disorders    Abstract    1: Rosacea and associated neurodegenerative and other diseases    2: Rosacea, dental focal infections, and other focal infections    3: Rosacea and face mask    4: Vagus, facial, and trigeminal nerve communications: Human micro-  biome—Face interaction    5: Small intestinal bacterial overgrowth in rosacea    6: Altered vasculature in rosacea: Angiogenesis and vasodilation    7: Rosacea and cancer    8: Rosacea and acne    9: Chalazia pathology and lidocaine effects    10: Demodex: Hordeola and cancer    11: Rosacea: The putative mechanisms    References    12

Chapter 23: Bacterial internalization in cancer and other medical conditions:  Intracellular pathogens    Abstract    1: Bacterial infection and bacteria internalization in cancer    2: Bacteria internalized by different cells evade killing by most antibi-  otics    3: Trace amines stimulate adhesion and internalization of staphy-  lococcal bacteria    4: Prevention and treatment of internalized (intracellular) bacterial inva-  sion    5: Intracellular bacteria in sexually transmitted infections    6: Intracellular bacteria in central nervous system    7: Intracellular bacteria in the peripheral nervous system    8: Bacteria and viruses intracellularly in pathogenic protozoan Acan-  thamoeba    9: Intracellular microorganisms in transfusion of blood components    10: Intracellular bacteria in plants   11: Intracellular and extracellular bacterial infections and autophagy in  dementia/neurodegeneration    12: Conclusions    References    Chapter 24: Ocular changes resulting from reading and writing on smart-  phone and computer: Computer vision syndrome, dry eye disease, meibo-  mian gland dysfunction, chalazion, occupational overuse syndrome    Abstract    References    13

Chapter 25: Viral infections in vagus nerve    Abstract    1: Introduction    2: Viruses in vagus nerve of humans    3: Viruses in the vagus nerve of experimental animals    4: COVID-19 and vagus nerve    5: Vagal nerve stimulator infections    6: Conclusions    References    Chapter 26: Microbial tryptamine in Type 1, Type 2, and Type 3 diabetes    Abstract    1: Types 1, 2, and 3 diabetes, β-cells, liver disease, hyperinsulinemia    2: Tryptamine role in diabetes    3: Diabetes and vagus nerve    4: Conclusions    References    Index 

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Copyright    Academic Press is an imprint of Elsevier  125 London Wall, London EC2Y 5AS, United Kingdom  525 B Street, Suite 1650, San Diego, CA 92101, United States  50 Hampshire Street, 5th Floor, Cambridge, MA 02139, United States  The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, United King-  dom    Copyright © 2023 Elsevier Inc. All rights reserved.    No part of this publication may be reproduced or transmitted in any form or  by any means, electronic or mechanical, including photocopying, recording,  or any information storage and retrieval system, without permission in writ-  ing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements  with organizations such as the Copyright Clearance Center and the Copy-  right

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www.elsevier.com/permissions.    This book and the individual contributions contained in it are protected  under copyright by the Publisher (other than as may be noted herein).    Notices  Knowledge and best practice in this field are constantly changing. As  new research and experience broaden our understanding, changes in  research methods, professional practices, or medical treatment may  become necessary.    Practitioners and researchers must always rely on their own expe-  rience and knowledge in evaluating and using any information, meth-  ods, compounds, or experiments described herein. In using such  information or methods they should be mindful of their own safety  and the safety of others, including parties for whom they have a pro-  fessional responsibility.    To the fullest extent of the law, neither the Publisher nor the authors, 

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contributors, or editors, assume any liability for any injury and/or  damage to persons or property as a matter of products liability,  negligence or otherwise, or from any use or operation of any meth-  ods, products, instructions, or ideas contained in the material here-  in.    ISBN 978-0-443-19122-0    For information on all Academic Press publications visit our website at  https://www.elsevier.com/books-and-journals   

  Publisher: Nikki P. Levy  Acquisitions Editor: Natalie Farra  Editorial Project Manager: Michaela Realiza  Production Project Manager: Niranjan Bhaskaran  Cover Designer: Christian Bilbow  Cover Art: Elena L. Paley    Typeset by STRAIVE, India 

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  Chapter 1: Introduction: Microbial metabolite interference of protein biosyn-  thesis in neurodegenerative, neurodevelopmental, and other disorders;  microbial metabolites hijacking vagus nerve 

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Abstract  My current studies focus on protein biosynthesis interference induced  by microbial metabolites in Alzheimer’s disease and associated med-  ical conditions.  Protein synthesis represents a major metabolic activity of the cell. Multifaceted deregulation of gene expression and protein synthesis was  observed with age.  The data reported on microbial and human tryptophan metabolite  tryptamine in virus infections including the most recent of 2021 are dis-  cussed in this book. I present here the conceptual model of food and gut microbial  tryptamine—vagus nerve circuit.  In this book, I put together a 1758 piece (citations) puzzle to under-  stand a mechanism of neurodegenerative and other associated dis-  eases to be able to test, prevent, and treat the diseases (Life Puzzle).   

Keywords    Protein biosynthesis; Alzheimer’s disease; Associated medical conditions;  Tryptophan metabolites; Gut microbial tryptamine; Vagus nerve circuit;  Life

puzzle

collection

of

citations;

Conceptual

model; 

N,N-dimethyl-tryptamine (DMT); Redox reaction    My current studies focus on protein biosynthesis interference induced by  microbial metabolites in Alzheimer’s disease and associated medical condi-  tions [1,2].  Protein synthesis represents a major metabolic activity of the cell. Multi-  faceted deregulation of gene expression and protein synthesis was observed  with age [3].  The gut microbiota contributes to host physiology through the produc-  tion of a myriad of metabolites. These metabolites exert their effects within  the host as signaling molecules and substrates for metabolic reactions. Al-  though the study of host-microbiota interactions remains challenging due to  the high degree of crosstalk both within and between kingdoms, metabolite-  focused research has identified multiple actionable microbial targets that  are relevant for host health [4]. 

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Human host protein biosynthesis is one of the main microbial targets.  We demonstrated that analog of essential amino acid tryptophan—the  microbial metabolite an inhibitor of protein biosynthesis biogenic amine  tryptamine shows multiple dose-dependent effects in vivo in cell and animal  models and in vitro. In our studies, tryptamine induces neurodifferentiation  [5,6], neurodegeneration [5–8], cytotoxicity, mitosis, and death of cancer  cells [5,6,9,10]. The data by other authors supported our findings of these ef-  fects. For instance, it was recently demonstrated that tryptamine adminis-  tration attenuated clinical signs of paralysis in mice [11]. Thus, tryptamine-  induced neurodifferentiation is supported by this study.  In the earlier study, tryptamine was produced in the midintestinal diver-  ticula in rats [12]. Removal of the intestinal pouch results in a reduction of  tryptamine metabolite indoleacetic acid to normal levels within 24 h, and  oral administration of neomycin promptly reduces the excretion of this com-  pound to normal levels [13]. Colonic diverticular disease may be associated  with increased risk for dementia [14]. There were 1057 dementia cases in the  diverticular disease cohort during the follow-up period of 315,171 person-  years; the overall incidence rate of dementia differed from that of the control  group (3.35 vs 2.43 per 1000 person-years, P 1.25 or  250; phenylethylamine 132; tyramine >250 [13]. Infection  of Huh-7.5 cells (well-differentiated hepatocyte derived cellular carcinoma  cell line) by SARS-CoV-2, HCoV-229E (human coronavirus), hPIV-3 (parain-  fluenza), and YFV 17D (yellow fever) viruses was explored for tryptamine  inhibition (IC50, μM) to be: 33, 50, 158, 218, respectively. Distribution of  anti-SARS-CoV-2 metabolites among culture broth extracts of human-  associated bacteria was demonstrated for representative culture (tryptamine  produced by 9 bacteria from 5 Phylum). Culture broth extracts from 50 phy-  logenetically diverse and commonly seen commensal bacteria were 

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screened in a cell-based assay for the ability to inhibit infection of human  cells by SARS-CoV-2 in this study [13].  Tanimoto and colleagues of Hiroshima University, Japan reported in  Scientific Reports of Nature (2021) [14] the inhibition of SARS-CoV-2 infec-  tion in vitro by suppressing its receptor, angiotensin-converting enzyme 2  (ACE2), via aryl-hydrocarbon receptor signal. The authors focused on the  internalization mechanism of SARS-CoV-2 via ACE2. Because RNA-seq anal-  ysis suggested that suppressive effects on ACE2 might be inversely corre-  lated with induction of the genes regulated by aryl hydrocarbon receptor  (AHR), the AHR agonists 6-formylindolo(3,2-b)carbazole (FICZ) and  omeprazole (OMP) were tested to assess whether those treatments affected  ACE2 expression. Both FICZ and OMP clearly suppressed ACE2 expression  in a dose-dependent manner along with inducing CYP1A1. Knock-down  experiments indicated a reduction of ACE2 by FICZ treatment in an AHR-  dependent manner. Finally, treatments of AHR agonists inhibited SARS-  CoV-2 infection into Vero E6 cells as determined with immunoblotting  analyses detecting SARS-CoV-2-specifc nucleocapsid protein. The re-  searchers demonstrate that treatment with AHR agonists, including FICZ,  and OMP, decreases expression of ACE2 via AHR activation, resulting in  suppression of SARS-CoV-2 infection in mammalian cells [14]. Several other  tryptophan metabolites, indole 3-carbinol, indoleacetic acid (10 and  100 μM), tryptamine (1, 10, and 100 μM), and L-kynurenine, and proton  pump inhibitors, rabeprazole sodium, lansoprazole, and tenatoprazole,  were also tested as to whether they regulate ACE2 gene expression; it was  demonstrated that most of them decreased gene expression of ACE2 with a  variety of actions and increased gene expression of CYP1A1 (100 μM  tryptamine increased expression of CYP1A1) in HepG2 cells (evaluated by  quantitative RT-PCR). Similar differences were also observed among cell  lines tested in this study. The authors suggested that optimization of each  compound will be necessary in the next steps (in vivo experiments and clin-  ical studies), although most of the tryptophan metabolites and proton  pump inhibitors seem to be safely applicable to clinical therapeutic re-  search. Furthermore, inhibitory effects of those compounds on infections  with SARS-CoV-2 variants would be interesting to test, since many muta-  tions in the virus have been reported so far. On the other hand, one limi-  tation of this strategy might be that these drugs do not target the 

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SARS-CoV-2 virus itself but just modify cellular susceptibility to it. Combi-  nation therapies of AHR agonists with antivirus drugs, such as favipiravir or  remdesivir, are therefore possible strategies for clinical application [14].  The nutrition contents of breastmilk directly participate in neonatal im-  mune response. The alterations of the components of breastmilk under the  context of viral infection not only reflect the physiological changes in moth-  ers but also affect neonatal immunity and metabolism via breastfeeding.  The authors from China answered the important questions whether breast-  milk production is affected by COVID-19 and whether breastfeeding is still a  safe or recommended operation for COVID-19 puerperant women (Yin Zhao  and colleagues, 2020) [15]. Proteomic and metabolic/lipidomic profiling of  colostrum samples from COVID-19 puerperant women and healthy volun-  teers is presented with overview of colostrum samples collected from  COVID-19 puerperant women (n = 4) and healthy volunteers (n = 2) [15].  Days between birth and breastmilk sample collection were within 3 days for  all patients. The pathway analysis revealed the alterations of aminoacyl-tRNA  biosynthesis and aromatic amino acid (AAA) metabolism as the notable  metabolic signatures. The data showed (Log2 fold change) that tryptophan  level (−2.14-fold) and tryptophan catabolism were significantly decreased in  breastmilk of COVID-19 patients. For instance, the microbial metabolites,  such as indole (−1.97-fold), indoleacetaldehyde (−1.95-fold), indole-3-acetic  acid (−1.858-fold), and tryptamine (−1.89-fold), which can be derived from  tryptophan, were significantly decreased in breastmilk of COVID-19 patients  [15]. Phenethylamine (phenylethylamine, PEA) was also decreased (−0.635)  in COVID-19 [15]. The authors suggested that the alterations of breastmilk  components were probably a reflection of the mother’s whole-body physio-  logical responses to COVID-19, or caused by SARS-CoV-2-mediated impact  on breastmilk production and/or secretion by mammary glands. Besides,  COVID-19 probably affects the bacteria in the body of puerperant women,  thereby resulting in the alterations of bacterial metabolites that can be se-  creted to breastmilk [15]. Guo and Tao (2018) selected milk biomarkers of pregnancy recognition in  dairy cows to provide a new insight and method for early pregnancy diag-  nosis. Ten healthy Holstein high-yielding dairy cows with similar body  condition and parity were selected. All cows were oestrus synchronized, and  their milk samples were collected at day 0 and day 17 of artificial 

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insemination. Metabolic profiles of the 2 groups of milk samples were  determined with LC-Q/TOF-MS metabolomics Differentiated metabolites  for the 2 groups of milk samples were selected according to VIP values  ( > 1) and P values ( 20; >20; >20; and 13.3 μg/mL = 83 μM (Yang et al., 1999) [27].  In the study by Arakaki and colleagues, the 83.9% of human T-acute lym-  phoblastic leukemia Jurkat cells survived after 72 h of incubation in the  presence of 100 μM tryptamine (as a percentage of the number of control  cells) [28].  Luqman and colleagues (2018) [29] demonstrated (Fig. S3) ∼10% cell  loss of human MonoMac6 (acute monocytic leukemia derived suspension 

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cell line) at 7.8 μg/mL tryptamine and about 40% loss at 62.5 μg/mL  tryptamine. The 10% loss of human monolayer line HEK293 adherent cells  (immortalized human embryonic kidney cells transformed with adenovirus 5  (Ad5)) was demonstrated after 24-h incubation with 125 μg/mL tryptamine.  Before the cytotoxicity assay, HEK293 cells were seeded in a 96-well mi-  crotiter flat-bottom plate with 10⁵ cells/well and incubated overnight at 37°C  in 5% CO . MonoMac6 cells (10⁵ per well) were seeded and incubated  2 under the same conditions as HEK293 cells for 1 h before treatment. The  host cells were treated with various concentrations of biogenic amines. The  cytotoxicity assay was performed using the Cell Proliferation Kit I (MTT;  Roche, Germany). At 570 and 690 nm (reference), the formed formazan  was determined [29]. The medium for cell cultivation in the cytotoxicity test-  ing is not indicated in this article. However, in the same report another cell  line HT-29, a human colorectal adenocarcinoma cell line with epithelial  morphology was used. HT-29 cells (5 × 10⁵ cells/well) were seeded in a 24-  well plate in DMEM medium with 10% fetal bovine serum (FBS) and antibi-  otic mix and incubated at 37°C in 5% CO for 48 h before the addition of  2 bacteria for adherence and internalization assay with the HT-29 cell line [29].  In my view, despite a high cell density for seeding and a short overnight  incubation with biogenic amines, tryptamine showed cytotoxicity in both  tested human cell lines—adherent HEK293 and suspension MonoMac6.  Metabolic cooperation is a form of cell communication in which the mutant  phenotype of enzyme deficient cells, as determined by incorporation of la-  beled substrates, is corrected in culture by contact with normal cells. Cell  communication is a more generalized phenomenon among cells in contact  than previously appreciated [30]. Cell density-dependent recovery of the  tryptamine-sensitive cells we observed due to metabolic cooperation in cell  culture [22]. This explains why cells MonoMac6 in suspension culture were  more sensitive to tryptamine than adherent cells HEK293.  The example of suggested metabolic cooperation in cultured Madin  Darby Bovine Kidney (MDBK) cells is demonstrated in Fig. 1.   

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Fig. 1 Cell density-dependent cytotoxicity of tryptamine due to  metabolic cooperation in kidney cell culture. (A and B) Effect of  tryptamine on MDBK cell viability. (A) 1.6 × l0 ⁶ cells per dish were  inoculated into a medium containing a specified tryptamine  concentration. Control dishes contained no inhibitors (A and B). (B)  Different cell quantities were plated in a medium with tryptamine  (25 μg/mL). The number of cells in the control dishes is 100%; cell  viability as a percent of the same day control. The 80-mm petri dishes  (Falcon), grown in a CO , incubator at 37°C for 9 days in RPMI 1640  2 medium. (C) Electron microscopy original magnification ×7500. Two  neighboring cells with visible contacts in adherent monolayer MDBK  kidney culture. Arrows show distinct intensities of immunostaining with  antibodies to tryptophanyl-tRNA synthetase (TrpRS) in two adjacent  cells in the monolayer culture. A cell with a higher TrpRS level can be  more resistant to tryptamine inhibition than a cell with a lower TrpRS  level (C). (C) TrpRS, a secreted protein can be secreted from a high  level TrpRS cell and then internalized by a cell with a lower TrpRS level  via the cell contacts (red arrowhead) . This can cause metabolic  cooperation observed in the cell culture (B). Data from E.L. Paley, V.N.  Baranov, N.M. Alexandrova, L.L. Kisselev, Tryptophanyl-tRNA  synthetase in cell lines resistant to tryptophan analogs, Exp. Cell Res. 

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195 (1991) 66–78.    We demonstrated the neuronal loss in human neuroblastic cells SH-SY5Y  and in hippocampus of the brain of mice [31]. The SH-SY5Y cells subline  was treated with 20–100 μg/mL (20 μg/mL = 102 μM) of tryptamine for  6–60  days. Neuronal loss was detected in Balb-c mice treated with  tryptamine injections (each injection of 200 μg of tryptamine in 0.2 mL of  noncomplete adjuvant for 2.5 week was administered for every second day).  Until the end of the experiments, the tryptamine mice were in good health  and visibly gained more weight than the control mice.  Blood glucose level, weight progression, and positron emission tomog-  raphy (PET) studies of glucose utilization after tryptamine administration of  200–400  μg/mouse, body weight 23–26 (200  μg/mouse ∼8  μg/  ∼8 μg/g = 8 mg/kg = 50 μM) were conducted in the Anna-Liisa  Brownell PET laboratory of Massachusetts General Hospital, Harvard Univ-  ersity (Paley and colleagues, 2007) [31] (Table 1).    Table 1    Blood glucose (mg/dL) 

Control animals 

Tryptamine treated 

138 ± 19 

129 ± 19 

Weight progression (%)  11.4 ± 4.5 

20.8 ± 3.8 (63 days) 

Glucose utilization, SUV  Whole brain 

0.94 ± 0.11 

0.95 ± 0.18 

Cerebellum 

0.72 ± 0.12 

0.68 ± 0.07 

Cingulate 

1.29 ± 0.10 

1.27 ± 0.13 

Hippocampus 

1.24 ± 0.11 

1.17 ± 0.17 

Olfactory area 

1.43 ± 0.21 

1.36 ± 0.13 

Striatum 

1.21 ± 0.12 

1.17 ± 0.16 

Indication of tryptamine cytotoxicity in insulin-producing β-cells of pancre-  atic islets.  Blood glucose level, weight progression, and PET studies of glucose utiliza-  tion after tryptamine administration 200–400 μg/mouse, body weight 23–  26 g (Paley et al., 2007).  The control mice injected with PBS and tryptamine-treated mice were exam-  ined. Standardized uptake values (SUVs). PET imaging with (18)F-FDG. Of  47

note, we demonstrated (2004) cytotoxicity and differential sensitivity be-  tween two pancreatic cell lines to 2-deoxy-d-glucose, a biologically active  molecule commonly used for PET [32].  Tryptamine induced the weight increase in mice (Table 1). Glucose utiliza-  tion by brain was reduced in cerebellum cingulate, hippocampus, olfactory  area, and striatum (Table 1). Of note, olfactory dysfunction is frequent in  COVID-19 [33]. In vitro autoradiographic techniques were used to examine  the distribution of [3H]tryptamine-binding sites in rat brain. The gross distri-  bution and pharmacological characteristics of binding to brain sections  resembled those seen in homogenate studies. Binding sites were found  throughout the brain, with a preponderance of sites in the forebrain and lim-  bic structures; highest levels were seen in the choroid plexus and the in-  terpeduncular

nucleus.

Other

regions

exhibiting

high

levels

of 

[3H]tryptamine binding include the cortex (especially lamina I), caudate  putamen, hippocampus, anterior olfactory nucleus, olfactory tubercle, nu-  cleus accumbens, amygdala, superior colliculus (superficial gray layer),  locus ceruleus, the nucleus of the solitary tract, and the pineal body (Perry,  1986) [34]. Importantly, [3H]tryptamine-binding sites are not identical to  MAO location in the rat brain (Perry and colleagues, 1988) [35]. Tryptamine-  induced hypoglycemia [36] and hyperinsulinemia [37] correlated with our  findings of tryptamine-induced decrease of blood glucose level in mice [31].  The effects of tryptamine on blood glucose levels were studied by Yamada  and colleagues (1988) [36]. Tryptamine induced significant hypoglycemia in  mice. The hypoglycemia elicited by tryptamine was strongly antagonized by  methysergide, an antagonist of both 5-HT and 5-HT receptors. A 5-HT   1 2 2 receptor antagonist, ketanserin, partially inhibited the tryptamine-induced  hypoglycemia. The effects of tryptamine on serum insulin levels were also  investigated by Yamada and colleagues (1990) [37]. Tryptamine induced an  apparent increase in serum insulin levels in mice. The elevation in insulin  elicited by tryptamine was potently antagonized by the 5-HT1 and 5-HT2  receptor antagonist, methysergide, but partially reduced by the 5-HT2 recep-  tor antagonist, ketanserin. However, the 5-HT3 receptor antagonist, ICS 205-  930, was without effect [37]. Hyperinsulinemia is an early indicator of meta-  bolic dysfunction. Hyperinsulinemia is strongly associated with type 2 dia-  betes. Hyperinsulinemia characterizes a prediabetic state [38,39] (Fig. 2).   

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Fig. 2 Early in the long process, which leads to type 2 diabetes, the  great majority of type 2 patients have hyperinsulinemia. The  representative depiction of the natural history of type 2 diabetes—the  fasting glucose and serum insulin [40].    Dopkins and colleagues (2020) [41] tested the ability of tryptamine to  ameliorate symptoms of experimental autoimmune encephalomyelitis  (EAE), a murine model of multiple sclerosis. Authors found that tryptamine  administration attenuated clinical signs of paralysis in EAE mice, decreased  the number of infiltrating CD4+ T cells in the CNS, Th17 cells, and RORγ T  cells while increasing FoxP3 + Tregs (Tregs is regulatory T cells). Model  mice were immunized on day 0 with subcutaneous injections containing  150 μg of myelin oligodendrocyte glycoprotein subunit 35-55 (MOG35-55)  and 600 mg heat-killed Mycobacterium tuberculosis (H37Ra) suspended  within an emulsion of PBS and Freund’s complete adjuvant On day 0 and 2,  mice received a single intraperitoneal injection containing 200 and 400 ng  of pertussis toxin, respectively. Beginning on day 1, mice received a 50 μL  intraperitoneal injection containing either a vehicle (sterile corn oil (CO)  with 2% DMSO v/v) or a treatment suspension (12.5 mg/kg = 12 μg/  kg = 12 μg/ tryptamine in sterile CO with 2% DMSO v/v) every 48 h. Au-  thors analyzed mice daily to observe paralysis symptoms and body weight  until any individual mice displayed a severity of symptoms that reflected a  moribund state and required euthanasia. At this point, observed at day 13, all 

49

mice were euthanized for uniform sample collection. Tryptamine-treated  mice demonstrated a significant reduction in paralysis symptoms beginning  from day 8 that persisted for the remaining duration of the study. The sum  of paralysis scores per mouse further demonstrates a significant reduction  in observed paralysis symptoms experienced between tryptamine vs vehicle  treatment groups. The average weight of mice was also measured through-  out the time course of chronic progressive EAE and the data expressed as  percent of starting body weight, clearly showed that while the vehicle-treated  group started losing weight, especially on days 11–13, the tryptamine-treated  mice showed a significant retention of weight when compared to the vehicle  controls. These results together demonstrated that tryptamine treatment of  EAE mice ameliorates the clinical symptoms of paralysis and weight loss  associated with EAE.  These data are consistent with our data on weight progression following  tryptamine treatment of mice (Table 1) and our earlier reported data (Paley  and colleagues, 2007) [31].  Donor cells were derived from wild type (WT) and Lck-Cre AHRflox/flox  mice and treated ex vivo in the presence of vehicle (DMSO) or 100 μM  + tryptamine prior to induction of disease [41]. The percentage of CD4 and  PCNA+ cells among all lymphocytes collected from immunized mice stimu-  lated in vitro with MOG35-55 in the presence or absence of tryptamine  demonstrated a reduction in proliferative activity. Tryptamine treatment in  vitro reduced the percentage of proliferating CD4+ T cells as demonstrated  by PCNA+ cells. Also, tryptamine treatment in vitro significantly reduced the  percentage of CD4+ RORγT as shown in a representative flow cytometric  analysis and the percentage of such cells from multiple samples [41].  + Thus, tryptamine at 100 μM is cytotoxic for proliferating CD4 T cells  that play important role in immune system.  Authors studied the effects of tryptamine treatment in vivo on the compo-  sition of the cecal microbiota in EAE mice [41]. The data demonstrated that  the cecal microbiota of treated mice was distinctly clustered from the vehi-  cle group. Dehalobacterium, Bacteroides, and Peptostreptococcaceae were sig-  nificantly altered in tryptamine-treated groups when compared to the vehicle  controls.  Using mass spectrometry, the data revealed a significant increase in  n-butyric acid following tryptamine treatment when compared to vehicle 

50

controls. These results suggested that tryptamine treatment alters the  microbiota in the gut and promotes the induction of n-butyric acid [41].  Jessica Wickline and colleagues (2019) [42] reported the in vitro effects of  tryptamine, harmine, and harmaline on Leishmania tarentolae and the pos-  sible implications for Leishmaniasis. Leishmaniasis is a disease caused by  Leishmania parasitic protozoans affecting people in both the Eastern and  Western Hemispheres [42]. The exact number of leishmaniasis cases is not  known but is reported to be between 1.5 and 2.0 million new cases per year  and over 150 million people affected worldwide. There were no apparent  changes in cell motility or shape in treated cells relative to control cells in  these trials. However, cells of day 3, 4, and 5 cultures exposed to either  harmine, harmaline, or tryptamine exhibit clumping differences relative to  control cells. Relative to control cells, exposure to harmine, harmaline, or  tryptamine resulted in about a 33%, 25% or 60% increase, respectively, in  number of cell clumps on day 5 (data not shown). This is of interest as the  cell clumping is reflective of cell stress. Also, the apparent clump size (re-  flective of the number of cells per clump) and clump shape were not iden-  tical to the control cells [42]. Effect of the compounds on L. tarentolae cell  viability was examined. In the presence of harmine (from 12.50 to 250.0 μM  final concentration), the cell viability was negatively affected at and above  62.50 μM on days 4, 5, and 6 of cultivation. The cultures exposed to  62.50 μM did appear to recover on day 7, whereas above that concentration,  cell viability remained very low. The same trend is shown with tryptamine  (12.5; 25; 62.50; 125; 187.5; 250 μM). The cells exposed to 12.50 μM (50%  inhibition after 1 day incubation and 157% growth stimulation on the day 7;  cell viability as a percent of the same day control) did exhibit an apparent  recovery effect not observed for any other concentration of tryptamine. For  cells exposed to the various concentrations of harmaline, the cell viability  appears less inhibited by addition of this compound relative to the other  two testes compounds [42]. Effect of tryptamine compounds on L. taren-  tolae secreted acid phosphatase activity (SAP) was examined. Tryptamine  has inhibitory effects on Day 5 (62.5, 125.0, and 250.0 μM) and Day 7 (62.5,  125.0, 187.5, and 250.0 μM) [42].  Luqman and colleagues (2021) [43] reported a study on effect of  tryptamine on Serratia marcescens, Pseudomonas aeruginosa, and Escherichia  coli. It was demonstrated that tryptamine at the concentrations 25–100 μg 

51

inhibits motility of E. coli (37.5%–62.5%) [43]. Tryptamine at the concen-  trations 50 and 100 μg/mL inhibit growth of E. coli (OD 600) during 8–  24 h incubation. Higher concentrations of tryptamine (∼125−1000 μg) in-  hibit the growth (OD 600 nm) of Serratia marcescens and Pseudomonas  aeruginosa.  In my view, the distinct sensitivity of examined bacteria to tryptamine  cytotoxic effects may cause dysbiosis in hosts including humans. The differ-  ential tryptamine cytotoxicity for microorganisms is important in dysbiosis  development especially because Smarcescens marcescens and Pseudomonas  aeruginosa are opportunistic human pathogens.  Effects of tryptamine on growth of six yeast species were explored (Kadkol  and Macreadie, 2018) [44]. Tryptamine inhibits growth of yeast, and in most  cases, the inhibitory effect by tryptamine was reduced by tryptophan addi-  tion [44]. This exemplifies the importance of controlling tryptophan concen-  tration in the medium for mammalian cell cultivation and tryptamine cyto-  toxicity determination. The results obtained in this study are consistent with  tryptamine competing with tryptophan to bind mitochondrial and cyto-  plasmic tryptophanyl tRNA synthetases in yeast. In addition, there is a vari-  ation in the sensitivity to tryptamine and the rescue by tryptophan in the  tested yeast species. Tryptamine (up to 115.7 mg/100 mL = 7 mM) is pro-  duced by yeasts isolated from artisanal short-ripened cows’ cheeses (Gali-  cia, NW Spain) [45]. Effects of increasing tryptamine concentrations (50,  100, 250, 500, 750, and 1000 mg/L = μg/mL) on wine yeast species  growth were examined in the minimal medium [1 mM (NH4)2SO4] by Beat-  riz González and colleagues (2018) [46]. Tryptamine influenced differently  the growth of yeast strains, resulting in increases in the lag phase or in the  variables generation time (GT), decreases (at 100–1000 μg/mL tryptamine)  in the maximal growth (OD max), and even no effects at all [46].  Tryptamine-producing fungi are toxic for insects. Deletion of fungal MAO  gene leads to tryptamine accumulation and to increase in the fungal viru-  lence (Tong and colleagues, 2020) [47]. High level of tryptamine can kill in-  sects. The insect locusts’ survival after the injection of different tryptamine  dosages (0.1, 1, 10, 100, and 1000 ng/insect) showed the median lethal  dose and sublethal dose during 4 days, The 40% survival was demon-  strated for 1 and 10 ng/insect while 100 ng resulted in 20% survival during  4 days [47]. One thousand nanogram tryptamine kills all the insects during 

52

4 days [47]. The toxicity of tryptamine to locusts was verified by first testing  its median lethal dosage (LD ), which was determined to be between 1.585  50 and 20.795 (ng/g) at 95% confidence interval, in locusts. This lethal dosage  confirmed the insecticidal efficiency of tryptamine on locusts. Cellular reac-  tive oxygen species (ROS) production was clearly observed in locusts 4 h  after the tryptamine injection (10 ng per insect). Tryptamine injection also  induced the upregulation of locust LmMao-a and LmMao-b MAO genes.  Moreover, the detoxification genes (cyp4 and cyp6) and immune response  genes (cactus, stubble, and easter) were upregulated by tryptamine injection.  Interestingly, the representative antimicrobial gene defensin was suppressed  [47].  Tryptamine was screened against different cyanobacteria and eukaryotic  microalgae by Churro and colleagues (2010). In a rapid 96-well microplate  bioassay cultures were exposed to tryptamine concentrations from 0.625 to  20 μg/mL and growth was estimated by daily optical measurements over a  216 h period (9 days). Inhibitory concentrations (IC50 216h) obtained from the sigmoidal inhibition curves showed that tryptamine prevents the growth  of most cyanobacteria and eukaryotic microalgae at similar concentrations.  The 20 μg/mL tryptamine inhibited growth of all 16 tested cyanobacteria  and algae species. Furthermore, the 20 μg/mL tryptamine induced 100%  cell loss for 14 of 16 tested cyanobacteria and algae species (excluding two  algae species Nannochloropsis sp. with maximum IC50 15.76 among tested  16 organisms, and Tetraselmis suecica with no observed effect (NOE)). IC   50 (μg/mL) was determined for 8 cyanobacteria species (1.05; 0.65; 2.36; 4.15;  1.13; 1.18; 9.22; 1.64) and 8 eukaryotic microalgae (1.53; 7.69; 0.48; 6.97;  10.22; NOE; 1.09; 15.76). Therefore, 14.5-fold maximum difference in IC   50 exist between different cyanobacteria and 32.83-fold maximum difference be-  tween different eukaryotic microalgae. However, most of the eukaryotic  algae recovered growth after being transferred to new tryptamine-free culture  media, while most cyanobacteria showed no growth recovery. Microscopy  examination of exposed cells showed no major effects of tryptamine on eu-  karyotic ultrastructure but showed major-induced alterations on cyanobac-  teria (disorganization of thylakoid membranes, intrathylakoidal vacuoliza-  tion, increased cytoplasmatic granules, and cell lysis). Biochemical analyses  performed on Aphanizomenon gracile (cyanobacteria) and Ankistrodesmus fal-  catus (chlorophyceae) showed that tryptamine induces an increase in H O   2 2

53

production in both cultures. Although no significant changes in catalase  activity were detected, both cultures showed an increase in ascorbate perox-  idase activity following tryptamine exposure treatments. Interestingly, lipid  peroxidation was found to increase only in Aphanizomenon gracile, suggesting that the cellular defense mechanisms triggered by this cyanobac-  terium were less efficient than the ones triggered by Ankistrodesmus falcatus  for the removal of reactive oxygen species (ROS) [48]. Transmission elec-  tron photomicrographs of tryptamine-treated cyanobacteria and algae pre-  sented [48]. Di Rienzi and colleagues reported that the human gut and  groundwater harbor nonphotosynthetic bacteria belonging to a new candi-  date phylum sibling to Cyanobacteria (2013) [49]. Bacteria belonging to the  phylum Cyanobacteria had a significant effect on the prehistoric Earth be-  cause they were the first organisms to produce gaseous oxygen as a byprod-  uct of photosynthesis, and thus shaped the Earth’s oxygen-rich atmosphere.  Early plants took up these bacteria in a symbiotic relationship, and plas-  tids—the organelles in plant cells that perform photosynthesis and produce  oxygen—are the descendants of Cyanobacteria. Organisms evolutionarily re-  lated to Cyanobacteria have been found in the human gut and in various  aquatic sources, but these bacteria have not been studied because it has not  been possible to isolate or culture them. Now, Di Rienzi, Sharon et al. have  used modern sequencing techniques to obtain complete genomes for some of these bacteria, which they assign to a new phylum called Melainabacteria  [49].  Cyanobacteria, also called blue-green algae, are microscopic organisms  found

naturally

in

all

types

of

water 

(https://www.cdc.gov/habs/pdf/cyanobacteria_faq.pdf).  Zhang and colleagues reported (2016) on algicidal activity of Streptomyces  eurocidicus metabolites [50]. Copper sulfate (CuSO ) has been widely used  4 as an algicide to control harmful cyanobacterial blooms (CyanoHABs) in  freshwater lakes. However, there are increasing concerns about this appli-  cation, due mainly to the general toxicity of CuSO to other aquatic species  4 and its long-term persistence in the environment. This study [50] reported  the isolation and characterization of two natural algicidal compounds, i.e.,  tryptamine and tryptoline, from Streptomyces eurocidicus JXJ-0089. At a con-  centration of 5 μg/mL, both compounds showed higher algicidal effi-  ciencies than CuSO4 on Microcystis sp. FACHB-905 and some other harmful 

54

cyanobacterial strains. Tryptamine and tryptoline treatments induced a  degradation of chlorophyll and cell walls of cyanobacteria. These two com-  pounds also significantly increased the intracellular oxidant content, i.e.,  superoxide anion radical (O (−)) and malondialdehyde (MDA), but re-  2 duced the activity of intracellular reductants, i.e., superoxide dismutase  (SOD), of cyanobacteria. Moreover, tryptamine and tryptoline treatments  significantly altered the internal and external contents of microcystin-LR  (MC-LR), a common cyanotoxin. Like CuSO4, tryptamine and tryptoline led  to releases of intracellular MC-LR from Microcystis, but with lower rates  than CuSO . Tryptamine and tryptoline (5 μg/mL) in cyanobacterial cul-  4 tures were completely degraded within 8 days, while CuSO4 persisted for  months. Overall, the authors suggest that tryptamine and tryptoline could  potentially serve as more efficient and environmentally friendly alternative  algicides than CuSO4 in controlling harmful cyanobacterial blooms [50].  EC of tryptamine on eight strains of cyanobacteria after 3 days of incu-  50 bation were determined as 1.82 ± 0.09 to 4.48 ± 0.28 μg/mL for 7 strains  and >5 μg/mL for one strain. Algicidal efficiency for 5 μg/mL tryptamine  was 80% for 8 days incubation [50]. At 1 μg/mL, tryptamine showed no  influence on the growth of cyanobacteria Microcystis sp. FACHB-1284 and  even promoted the growth of Microcystis sp. FACHB-1285 by 16% [50].  Therefore, tryptamine alters the gut microbial profile. The distinct sensi-  tivity of examined bacteria and yeasts to tryptamine cytotoxicity may cause  dysbiosis in humans. The strains of bacteria and yeast species synthesizing  high concentrations of tryptamine can be resistant to these tryptamine con-  centrations and thus can be overproduced in the medium with tryptamine  while tryptamine-sensitive microorganisms can be inhibited or killed.   

1.3: Tryptamine-interacting proteins  The tryptamine-interacting protein tryptophanyl-tRNA synthetase (TrpRS) is  responsible for virus entry. Yeung et al. (2018) provide evidence of a novel  EV-A71 entry factor, a host-produced tryptophanyl-tRNA synthetase that  facilitates entry of multiple subtypes of enteroviruses [51]. Human TrpRS  (hTrpRS) is a cytoplasmic enzyme that is essential for translation but also  upregulated and secreted during inflammatory processes. The results of this  study support the notion of secreted hTrpRS as an unconventional virus  entry factor that raises interesting questions about mechanisms by which in-  flammation and a tRNA synthetase facilitate viral pathogenesis [51]. 

55

We revealed histochemically the secreted human TrpRS inside the brain  blood vessels of Alzheimer’s disease [19], whereas hTrpRS existing as au-  toantigen [52] is identified as one of the autoantigens in COVID-19 [53–55].  TrpRS amplify innate inflammatory responses via the triggering receptor ex-  pressed on myeloid cells (TREM)-1, which is an amplifier of pro-  inflammatory processes (Nguyen and colleagues 2020) [56]. Furthermore,  cytoplasmic TrpRS (WARS1) promoted TREM-1 downstream phospho-  rylation of DAP12, Syk, and AKT. Knockdown of TREM-1 and inhibition of  Syk kinase lead to p38 MAPK, ERK, and NF-κB inactivation. TREM-1 sig-  naling pathway was shown to be involved in WARS1-triggered massive pro-  duction of IL-6, TNF-α, IFN-β, MIP-1α, MCP-1, and CXCL2, where acti-  vation of Syk kinase was crucial [56]. In the review of the concept of proin-  flammatory cytokines, the cytokines are regulators of host responses to  infection, immune responses, inflammation, and trauma (Dinarello, 2000)  [57]. Some cytokines act to make disease worse (proinflammatory), whereas  others serve to reduce inflammation and promote healing (antiin-  flammatory). Attention also has focused on blocking cytokines, which are  harmful to the host, particularly during overwhelming infection. Interleukin  (IL)-1 and tumor necrosis factor (TNF) are proinflammatory cytokines, and  when they are administered to humans, they produce fever, inflammation,  tissue destruction, and, in some cases, shock and death (Dinarello, 2000)  [57]. Inflammation clearly occurs in pathologically vulnerable regions of the  Alzheimer’s disease (AD) brain, and it does so with the full complexity of  local peripheral inflammatory responses [58]. Furthermore, we discovered  TrpRS in extracellular plaques (2007) [59] and inside blood vessels in brains  of Alzheimer’s disease patients, while tryptamine induces vasculopathies in  the brains of mice (Paley and colleagues) [59,60]. TrpRS of human  macrophages infected by Porphyromonas gingivalis induces a proinflam-  matory response associated with atherosclerosis (Sasaki and colleagues,  2021) [61]. Porphyromonas gingivalis is the most common microorganism  associated with adult periodontal disease, causing inflammation around the  subgingival lesion [61]. Porphyromonas gingivalis is an intracellular bacterium  and successful colonizer of oral tissues (Yilmaz et al., 2008) [62]. Porphy-  romonas gingivalis, the keystone pathogen in chronic periodontitis, was iden-  tified in the brain of Alzheimer’s disease patients [63]. The nervous system  is shielded from circulating immune cells by the blood-brain barrier (BBB). 

56

During infections and autoimmune diseases, macrophages can enter the  brain where they participate in pathogen elimination but can also cause tis-  sue damage. The local, (micro)glial clearance mechanisms are generally  sufficient in a healthy animal but can become overloaded in case of infec-  tion or during neurodegenerative and/or autoimmune diseases. These in-  sults can trigger the extravasation of circulating lymphocytes and  macrophages across the BBB into the brain, which will clear pathogens and  cellular debris but which can also result in further brain damage (Winkler  and colleagues, 2021) [64]. Winkler and colleagues (2021) revealed in  Drosophila that brain inflammation triggers macrophage invasion across  the blood-brain barrier [64]. Biogenic amines were detected in human saliva  using a screen-printed biosensor (Piermarini and colleagues, 2010) [65].  Tryptamine was higher in saliva of 45 patients with recurrent aphthous ulcer  (RAS) compared to 49 healthy individuals (Li and colleagues, 2018) [66]. In-  creased Porphyromonadaceae and Veillonellaceae species were seen in ulcer-  ated sites of RAS (Hijazi and colleagues, 2015) [67]. In the study by Dopkins  and colleagues (2020) [41], tryptamine treatment (12.5 mg/kg every 48 h)  caused alterations in the gut microbiota and promoted butyrate production.  In this article, the principal coordinate analysis (PCoA) plot is displaying  unique clustering of the cecal microbiota among mice treated with vehicle vs. mice treated with tryptamine (n = 5 per group). Relative abundance  (tryptamine-treated versus vehicle) of Dehalobacterium (increase), Bac-  teroides (decrease), and Peptostreptococcaceae (significantly increased)  within the cecal content based on 16 s sequencing reads (n = 5 per group)  was demonstrated. Tryptamine treatment alters neuroinflammation in mice  with EAE, a murine model of multiple sclerosis (Dopkins and colleagues,  2020). In this study, tryptamine treatment (days 6th to 13th) increased  weight of mice while paralysis symptoms reduced (tryptamine 12.5 mg/kg  every 48 h) [41].  Rams and colleagues of University of Pennsylvania (1992) [68] reported  that anaerobic bacteria Peptostreptococcus micros (Class: Clostridia, Order:  Clostridiales, Family: Peptostreptococcaceae), a recognized pathogen in  medical infections, was examined and its association with progressive peri-  odontitis was demonstrated. Peptostreptococcus micros was isolated from  paper-point subgingival samples on anaerobic enriched blood agar plates  and identified on the basis of cellular and colonial morphology and selected 

57

biochemical tests. In a cross-sectional study involving 907 people with ad-  vanced adult periodontitis, 127 with early-onset periodontitis, and 12 with  localized juvenile periodontitis, Peptostreptococcus micros occurred with a  prevalence of 58%–63%. In culture-positive patients, Peptostreptococcus mi-  cros averaged 12%–15% of total viable counts. Peptostreptococcus micros  demonstrated similar occurrence and proportional recovery in all age  groups. In a longitudinal study of 91 adult periodontitis patients on mainte-  nance therapy, Peptostreptococcus micros demonstrated a significantly higher  prevalence in disease-active than in disease-inactive patients (47% vs 14%).  Mechanical subgingival debridement and 0.12% chlorhexidine pocket irri-  gation were unable to eradicate subgingival Peptostreptococcus micros from  18 of 22 adult periodontitis patients. In vitro antimicrobial susceptibility test-  ing showed Peptostreptococcus micros to be sensitive to therapeutic levels of  penicillin, clindamycin, and metronidazole. The authors concluded that Pep-  tostreptococcus micros is a potential pathogen in adult periodontitis [68]. The  mouth is home to about 700 species of bacteria, including those that can  cause periodontal (gum) disease. A recent analysis led by NIA scientists  suggests that bacteria that cause gum disease are also associated with the  development of Alzheimer’s disease and related dementias, especially vas-  cular dementia. The results were reported in the Journal of Alzheimer’s Dis-  ease (2020): Clinical and Bacterial Markers of Periodontitis and Their As-  sociation with Incident All-Cause and Alzheimer’s Disease Dementia in a  Large National Survey [69].  The alterations in neuro-inflammation attributed to tryptamine treatment  probably caused by tryptamine cytotoxicity and tryptamine-induced inhi-  bition of protein biosynthesis.  Another tryptamine-interacting protein is human serum albumin (HSA)  [19], whereas SARS-CoV-2 is bound to HSA [70]. One of the key factors in  COVID-19 infection is its almost unique age-related profile, with a doubling  in mortality every 10 years after the age of 50. HSA, the most abundant pro-  tein in plasma, is created in the liver, which also maintains its concen-  tration, but this reduces by 10%–15% after 50 years of age. HSA transports  hormones, free fatty acids, and maintains oncotic pressure, but SARS-CoV-2  virions bind competitively to HSA diminishing its normal transport func-  tion. Furthermore, hypoalbuminemia is frequently observed in patients with  such conditions as diabetes, hypertension, and chronic heart failure, i.e., 

58

those most vulnerable to SARS-CoV-2 infection [70].  Moreover, chronic kidney disease, low serum albumin, and anemia are  known risk factors for cognitive decline in older people [71]. Both  Alzheimer’s disease (AD) and COVID-19 are age-dependent diseases with a  high prevalence of obesity and diabetes [19,72].  Hypoalbuminemia, coagulopathy, and vascular disease have been linked  in COVID-19 and have been shown to predict outcome independent of age  and morbidity. Hypoalbuminemia is also known factor in sepsis and acute  respiratory distress syndrome [70].  I therefore conclude that albumin binding to SARS-CoV-2 virions may inhibit the formation of bonds linking tryptamine with HSA thus releasing  tryptamine and increasing the level of the cytotoxic free tryptamine. 

59

2: Hospital-acquired infections  Wang et al. retrospectively evaluated all patients with a confirmed diagnosis  of bacterial infection at a tertiary general hospital in Jining, China, for the pe-  riod between January 2012 and December 2014 [73]. Bacterial identification  and susceptibility testing were performed. The authors screened a total of  15,588 patients, out of which 7579 (48.6%) had a hospital-acquired infec-  tions (HAIs) [73]. HAIs, also called nosocomial infections, affect the clinical  outcomes in hospitalized patients and represent a serious concern world-  wide [74]. Tsalik et al. reported in 2016 that infection poses a substantial risk  to hospitalized patients, particularly those in intensive care units (ICUs). Re-  cent estimates indicate that 1.7 million HAIs occur annually in US hospitals,  costing $9.8 billion and causing approximately 100,000 deaths. Hospital-  acquired pneumonia, including ventilator-associated pneumonia, accounts  for approximately 20% of all HAIs; however, the high mortality rate of 10%–  50% results in the greatest relative number of HAI deaths (∼36,000 annually) [74]. The base-case analysis assumed 17.6% of ventilated patients and  11.2% of nonventilated patients develop hospital-acquired infection and that  28.7% of patients with hospital-acquired infection experience delays in  appropriate antibiotic therapy with standard care [74]. 

60

3: COVID-19 and bacterial infections  Previously, I discussed coinfections with different microorganisms includ-  ing bacteria in COVID-19 patients [6]. In the nonhuman primates (macaque) infected with SARS-CoV-2, some changes were observed in the relative bacterial taxon abundance in gut microbiota associated with infectious  parameters. Notably, the relative abundance of Acinetobacter (Proteobac-  teria) and some genera of the Ruminococcaceae family (Firmicutes) of gut  microbiota was positively correlated with the presence of SARS-CoV-2 in the  upper respiratory tract [4].  Cox and colleagues reported in 2020 [75] that poor outcomes in the 2009  H1N1 influenza pandemic were associated with bacterial coinfections, al-  though few studies captured these data.  Particularly, MacIntyre and colleagues (2018) [76] revealed that fatal cases  with autopsy specimen testing were reported in 11 studies, in which any  coinfection was identified in 23% of cases (Streptococcus pneumoniae 29%).  Eleven studies of 2009 influenza pandemic reported bacterial coinfection  among hospitalized cases of A(H1N1)2009pdm with confirmed pneumonia,  with a mean of 19% positive for bacteria (Streptococcus pneumoniae 54%). Of  16 studies of intensive care unit (ICU) patients, bacterial coinfection iden-  tified in a mean of 19% of cases (Streptococcus pneumoniae 26%). The mean  prevalence of bacterial co-infection was 12% in studies of hospitalized pa-  tients not requiring ICU (Streptococcus pneumoniae 33%) and 16% in studies  of pediatric patients hospitalized in general or pediatric intensive care unit  (PICU) wards (Streptococcus pneumoniae 16%) [76]. Despite the proven  importance of co-infections in the severity of respiratory diseases, they are  understudied during large outbreaks of respiratory infections. Zhou and col-  leagues [77] showed that in the current coronavirus disease 2019 (COVID-  19) pandemic, 50% of patients with COVID-19 who have died had secondary  bacterial infections, and Chen and colleagues [78] have recorded both bacte-  rial and fungal co-infections.  Zhu et al. (2020) conducted a retrospective study of 257 laboratory-  confirmed COVID-19 patients in Jiangsu Province, China, that were enrolled  from January 22 to February 2, 2020 [79]. They were reconfirmed by real-  time RT-PCR and tested for 39 respiratory pathogens. In total, 24 respiratory  pathogens were found among the patients, and 242 (94.2%) patients were  coinfected with one or more pathogens. Bacterial coinfections were 

61

dominant in all COVID-19 patients, Streptococcus pneumoniae was the most  common, followed by Klebsiella pneumoniae and Haemophilus influenzae.  Most coinfections occurred within 1–4 days of onset of COVID-19 disease.  In addition, the proportion of viral coinfections, fungal coinfections, and  bacterial-fungal coinfections were the highest in severe COVID-19 cases.  There were 10, 22, 20, and 13 pathogens found in symptomatic, mild, mod-  erate, and severe/critical cases, respectively. Streptococcus pneumoniae, K.  pneumoniae, H. influenzae, fungi Aspergillus, EB virus, E. coli, and Staphy-  lococcus aureus were simultaneously found in four clinical groups. Moraxella  catarrhalis and Acinetobacter baumannii were found in asymptomatic cate-  gory, mild category and moderate category. The 81 patients (31.5%) had viral  coinfection, 236 (91.8%) had bacterial coinfection, and 60 (23.3%) had fun-  gal coinfection [79].  Asmarawati et al. (2021) reported [80] that data on the prevalence of  bacterial co-infections among COVID-19 patients are limited, especially in  Indonesia. The authors aimed to assess the rate of bacterial co-infections in  hospitalized COVID-19 patients and report the most common micro-  organisms involved and the antibiotic use in these patients. This study is a  retrospective cohort study, among COVID-19 adult patients admitted to  Universitas Airlangga Hospital Surabaya from March 14 to September 30,  2020 [80]. The bacterial infection is defined based on clinical assessment,  laboratory parameters, and microbiology results. A total of 218 patients with  moderate to critical illness and confirmed COVID-19 were included in this  study. Bacterial infection was confirmed in 43 patients (19.7%). COVID-19  patients with bacterial infections had longer hospital length of stay  (17.6 ± 6.62 vs 13.31 ± 7.12), a higher proportion of respiratory failure,  intensive care treatment, and ventilator use. COVID-19 patients with bacte-  rial infection had a worse prognosis than those without bacterial infection  (P 50% of patients). Most reported pa-  tients were symptomatic. Fever, dry cough, and dyspnea were the most  commonly reported symptoms. Most reported TB patients had been found  to have M. tuberculosis from sputum culture in the background of pulmonary  TB. Most patients of TB were treated with multidrug regimen antitubercular  therapy. In all 8 studies, COVID-19 was treated as per the local protocol.  Mortality was reported in more than 10% of patients. Mortality was higher in  elderly patients (>70 years) and among patient with multiple medical  comorbidities [34]. The one study reported that 41% of the patients were  smokers, 31% of the patients were unemployed, and 20% of the patients had  a history of alcohol abuse [34]. At the time of the article submission, the  countries reporting TB and COVID cases have been Belgium, Brazil, France,  Italy, Russia, Singapore, Spain, Switzerland, India, and China. Among these,  Italy has reported the highest percentage of cases (51%).  Berney and Berney-Meyer (2017) discussed the M. tuberculosis in the host  nutrient limitation [35]. Based on the current literature, M. tuberculosis has  the capacity to take up most amino acids and cofactors in vitro. However,  this ability to scavenge essential building blocks does not translate to the in  vivo situation in the presence of intact innate and adaptive immunity [35].  According to World Health Organization (WHO) every year, 10 million  people fall ill with TB. Despite being a preventable and curable disease, 1.5  million people die from TB each year—making it the world’s top infectious  killer. TB deaths rise for the first time in more than a decade due to 

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COVID-19 pandemic. Challenges with providing and accessing essential TB  services have meant that many people with TB were not diagnosed in 2020.  The number of people newly diagnosed with TB and those reported to na-  tional governments fell from 7.1 million in 2019 to 5.8 million in 2020. Fur-  thermore, WHO estimates that some 4.1 million people currently suffer  from TB but have not been diagnosed with the disease or have not officially  reported to national authorities. This figure is up from 2.9 million in 2019  reported by Tony Kirby in Lancet (2021) [36].  Tata and colleagues (2020) revealed that serum tryptamine increases in  M. avium subsp. infected and infectious animals cattle [37]. M. avium  subsp. paratuberculosis (MAP) is the causative agent of paratuberculosis  [Johne’s disease (JD)], a chronic disease that causes substantial economic  losses in the dairy cattle industry. The long incubation period means clinical  signs are visible in animals only after years, and some cases remain unde-  tected because of the subclinical manifestation of the disease. Considering  the complexity of JD pathogenesis, animals can be classified as infected,  infectious, or affected. The major limitation of currently available diagnostic  tests is their failure in detecting infected noninfectious animals. The authors  aimed to identify metabolic markers associated with infected and infectious  stages of JD [37]. From the collection of sera stored at −80°C, 17 sera of  infectious animals, 10 sera of infected animals, and 20 sera of negative ani-  mals were selected and then analyzed. High levels of tryptamine (involved  in tryptophan metabolism) observed in both infected and infectious animals  [37] correlates with important changes in protein turnover or deficiencies in  MAP-infected cattle revealed by De Buck and colleagues (2014) by  metabolomic profiling of cattle experimentally infected with MAP [38].  Due to the similarities between Crohn's disease and Johne’s disease, a  chronic

enteritis

in

ruminant

animals

caused

by  M.

avium 

paratuberculosis (MAP) infection, MAP has long been considered to be a  potential cause of Crohn's disease [39]. Crohn's disease is a chronic inflam-  matory bowel disease of unknown cause, affecting approximately 1.4 million  North American people. MAP can be cultured from the peripheral mononu-  clear cells from 50% to 100% of patients with Crohn's disease and less fre-  quently from healthy individuals. Association does not prove causation. Mc-  Nees and colleagues (2015) discussed the current data regarding MAP as a  potential cause of Crohn's disease and outlined what data will be required to 

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firmly prove or disprove the hypothesis [39].  Diel and colleagues reported (2018) that the incidence of nontuberculous  mycobacterial (NTM) pulmonary disease caused by M. avium complex  (MAC) in apparently immune-competent people is increasing worldwide  [40]. Despite high heterogeneity, most studies in patients with MAC pul-  monary disease document a 5-year all-cause mortality exceeding 25%, indi-  cating poor prognosis [40].  Pan and colleagues (2020) isolated Mycobacterium strain Mya-zh01 from  the flower stalk of orchid Doritaenopsis Jiuhbao Red Rose [41]. Mya-zh01 can  effectively produce and secrete the plant growth hormone indole-3-acetic  acid (IAA). Authors sequenced and assembled chromosome for Mya-zh01  (5,027,704 bp with 68.48% GC content), which was predicted to encode  4968 proteins with functions in oxidation reduction, growth, plasma mem-  brane, ATP and DNA binding, carbon metabolism, and biosynthesis of  amino acids pathways. Four pathways (tryptamine, indole-3-acetamide, in-  dole-3-pyru-vate, and flavin monooxygenase) and seven enzymes [tryp-  tophan synthase alpha chain, tryptophan synthase beta chain, amidase,  monoamine oxidase, indole-3-pyruvate monooxygenase, indole-3-pyruvate  decarboxylase, and aldehyde dehydrogenase (NAD+)] involved in IAA  biosynthesis were predicted in Mya-zh01 genome. Tryptamine was con-  verted into IAAId (indole-3-acetaldehyde) by monoamine oxidase (MAO)  and oxidized in IAA. Mya-zh01 is identified as M. avium[41]. Species distri-  bution of Mya-zh01 genome sequence was analyzed. Nearly 90% of coding  genes can be annotated against the 5 top-hit species, including M. avium,  M. intracellulare, Mycobacterium sp., M, tuberculosis, and M. marinum[41].  Karl and colleagues (2017) revealed changes in intestinal microbiota  composition and metabolism associated with increased intestinal perme-  ability in young adults under prolonged physiological stress [42]. This study used a systems biology approach and a multiple-stressor military training  environment to determine the effects of physiological stress on intestinal  microbiota composition and metabolic activity, as well as intestinal perme-  ability (IP). Soldiers (n = 73) were provided three rations per day with or  without protein- or carbohydrate-based supplements during a 4-day cross-  country ski-march (STRESS). IP was measured before and during STRESS.  Blood and stool samples were collected before and after STRESS to measure inflammation, stool microbiota, and stool and plasma global

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metabolite profiles. IP increased 62 ± 57% (mean ± SD, P 6 μM 

Histamine 

3107 ± 1593 

>5 μM 

Serotonin 

>6 μM 

>10 μM 

Norepinephrine 

>10 μM 

>5 μM 

Values represent the average ± SEM from n ≥ 3 experiments. Binding K s  i were determined from displacement of [³H]tyramine (20  nM) and  EC  values were determined by increases in cAMP accumulation. This  50 table adapted from the article by Borowsky and colleagues (2001) [38].  Human receptor TA1 (TAAR1) mRNA was detected by quantitative reverse  transcription (RT)-PCR in low levels in discrete regions within the central  nervous system (CNS) and in several peripheral tissues. Moderate levels  (100 copies/ng cDNA) were expressed in stomach, low levels (15–100) ex-  pressed in amygdala, kidney, lung, and small intestine, whereas trace  amounts ( thyronamine = octopamine = beta-topamine = -  phenylethy- while tryptamine and p-tyramine are significantly less active [42].   

8.4: Gastrointestinal tract (gut)  Ito et al. (2009) demonstrated that TAAR1, TAAR2, and GPRC5A mRNAs  were preferentially expressed in the mucosal layer of gastrointestinal tract of  C57BL/6J mice, suggesting their potential roles in the regulation of secretion  [43].  Gwilt et al. (2019) [44] reported that tissue-resident macrophages and pe-  ripherally infiltrating macrophages play a prominent role in maintaining 

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homeostasis in the gastrointestinal tract, though aberrant activation is  implicated in inflammatory conditions, including ulcerative colitis (UC).  Metabolomic studies indicate that tyramine is elevated in the stool of pa-  tients with UC. Tyramine activates the mammalian trace amine-associated  receptor 1 (TAAR1). To investigate whether TAAR1 may serve as a novel tar-  get for an antiinflammatory therapeutic in UC, TAAR1 expression was exam-  ined in mouse bone marrow-derived macrophages (BMDMs), and its up-  regulation and activation in response to LPS and TYR. The authors demon-  strated that TAAR1 is expressed in BMDM and undergoes agonist-induced  upregulation. These data suggest that TAAR1 is a mediator of macrophage  inflammation and a potential therapeutic target to attenuate UC sympto-  mology [44]. In study conducted by Gwilt et al. (2019), experimental colitis  was induced in mice by administering 3% dextran sulfate sodium (DSS) in  −/− the drinking water of 8-week old WT and TAAR1 littermates (n = 2 per  −/− group), for 7 days. The TAAR1 mice appear to be more resilient to the  onset of DSS colitis, with reduced weight loss (12% loss vs 15% loss), re-  duced colon length shortening TAAR1−/− (24% loss vs 33% loss), and fewer  inflamed lesions in the TAAR1−/− compared to WT sections. TAAR1−/−  mice also retained characteristics of a healthy colon including crypt mor-  phology and presence of goblet cells. The authors proposed that TAAR1 is  involved in gastrointestinal homeostasis [45].   

8.5: Thyroid gland  Szumska et al. (2015) demonstrated localization of the TAAR1 at the apical  plasma membrane domain of Fisher rat thyroid epithelial cells confined to  cilia [46]. The authors employed immunofluorescence microscopy and a  polyclonal antibody to detect Taar1 protein expression in thyroid tissue from  Fisher rats, wild-type and taar1-deficient mice, and in the polarized FRT cells  [46].   

8.6: Conclusion  Thus, TAARs present in the organs innervated or modulated by vagus nerve  including olfactory system, heart, gastrointestinal tract (gut), and thyroid  gland. 

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9: Conclusion  Elevation of gut microbial tryptamine induced by SARS-CoV-2 viral infection  may play a causative role in olfactory and gustatory dysfunction via at least  two receptors—trace amine-associated and NMDA (Fig. 1). Fig. 1 illustrates  schematically the pathways discussed in this chapter.   

Fig. 1 Gut microbial tryptamine as a putative causative factor of  olfactory and gustatory impairments. 

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References    [1] Beecher K., St John J., Chehrehasa F. Factors that modulate olfactory  dysfunction. Neural Regen. Res. 2018;13:1151–1155.  [2] Garcia-Diaz D.E., Aguilar-Baturoni H.U., Guevara-Aguilar R., Wayner  M.J. Vagus nerve stimulation modifies the electrical activity of the olfac-  tory bulb. Brain Res. Bull. 1984;12:529–537.  [3] Maharjan A., Wang E., Peng M., Cakmak Y.O. Improvement of olfac-  tory function with high frequency non-invasive auricular electros-  timulation in healthy humans. Front. Neurosci. 2018;12:225.  [4] Vance K.M., Rogers R.C., Hermann G.E. NMDA receptors control  vagal afferent excitability in the nucleus of the solitary tract. Brain Res.  2015;1595:84–91.  [5] King M.S. Anatomy of the rostral nucleus of the solitary tract. In:  Bradley R.M., ed. The Role of the Nucleus of the Solitary Tract in Gusta-  tory

Processing.

2007.

(Chapter

2).

Available

from: 

https://www.ncbi.nlm.nih.gov/books/NBK2541/.  [6] Berger M.L., Palangsuntikul R., Rebernik P., Wolschann P., Berner  H. Screening of 64 tryptamines at NMDA, 5-HT1A, and 5-HT2A recep-  tors: a comparative binding and modeling study. Curr. Med. Chem.  2012;19:3044–3057.  [7] Bromley S.M. Smell and taste disorders: a primary care approach.  Am. Fam. Physician. 2000;61: 427–436, 438.  [8] Malaty J., Malaty I.A. Smell and taste disorders in primary care. Am.  Fam. Physician. 2013;88:852–859.  [9] Butowt R., Meunier N., Bryche B., von Bartheld C.S. The olfactory  nerve is not a likely route to brain infection in COVID-19: a critical re-  view of data from humans and animal models. Acta Neuropathol.  2021;141:809–822.  [10] Agyeman A.A., Chin K.L., Landersdorfer C.B., Liew D., Ofori-Asenso  R. Smell and taste dysfunction in patients with COVID-19: a systematic  review and meta-analysis. Mayo Clin. Proc. 2020;95:1621–1631.  [11] Marshall M. COVID’s toll on smell and taste: what scientists do  and don’t know. Nature. 2021;589:342–343.  [12] Vitale A.A., Pomilio A.B., Canellas C.O., Vitale M.G., Putz E.M.,  Ciprian-Ollivier J. In vivo long-term kinetics of radiolabeled N,N-  dimethyltryptamine and tryptamine. J. Nucl. Med. 2011;52:970–977. 

364

[13] Cameron L.P., Benson C.J., DeFelice B.C., Fiehn O., Olson D.E.  Chronic,

intermittent

microdoses

of

the

psychedelic

N,N-

dimethyltryptamine (DMT) produce positive effects on mood and anx-  iety in rodents. ACS Chem. Neurosci. 2019;10:3261–3270.  [14] Paley E.L., Denisova G., Sokolova O., Posternak N., Wang X.,  Brownell A.L. Tryptamine induces tryptophanyl-tRNA synthetase-  mediated neurodegeneration with neurofibrillary tangles in human cell  and mouse models. NeuroMolecular Med. 2007;9:55–82.  [15] McCormack J.K., Beitz A.J., Larson A.A. Autoradiographic local-  ization of tryptamine binding sites in the rat and dog central nervous  system. J. Neurosci. 1986;6:94–101.  [16] Timmermann C., Roseman L., Williams L., Erritzoe D., Martial C.,  Cassol H., Laureys S., Nutt D., Carhart-Harris R. DMT models the neardeath experience. Front. Psychol. 2018;9:1424.  [17] Dean J.G., Liu T., Huff S., Sheler B., Barker S.A., Strassman R.J.,  Wang M.M., Borjigin J. Biosynthesis and extracellular concentrations of  N,N-dimethyltryptamine (DMT) in mammalian brain. Sci. Rep.  2019;9:9333.  [18] Alamia A., Timmermann C., Nutt D.J., VanRullen R., Carhart-Harris  R.L. DMT alters cortical travelling waves. elife. 2020;9.  [19] Sokol H., Contreras V., Maisonnasse P., Desmons A., Delache B.,  Sencio V., Machelart A., Brisebarre A., Humbert L., Deryuter L., Gau-  liard E., Heumel S., Rainteau D., Dereuddre-Bosquet N., Menu E., Ho  Tsong Fang R., Lamaziere A., Brot L., Wahl C., Oeuvray C., Rolhion N.,  Van Der Werf S., Ferreira S., Le Grand R., Trottein F. SARS-CoV-2 infec-  tion in nonhuman primates alters the composition and functional activ-  ity of the gut microbiota. Gut Microbes. 2021;13:1–19.  [20] Doty R.L., Reyes P.F., Gregor T. Presence of both odor identi-  fication and detection deficits in Alzheimer’s disease. Brain Res. Bull.  1987;18:597–600.  [21] Kreisl W.C., Jin P., Lee S., Dayan E.R., Vallabhajosula S., Pelton G.,  Luchsinger J.A., Pradhaban G., Devanand D.P. Odor identification abil-  ity predicts PET amyloid status and memory decline in older adults. J.  Alzheimers Dis. 2018;62:1759–1766.  [22] Seubert J., Laukka E.J., Rizzuto D., Hummel T., Fratiglioni L., Back-  man L., Larsson M. Prevalence and correlates of olfactory dysfunction 

365

in old age: a population-based study. J. Gerontol. A Biol. Sci. Med. Sci.  2017;72:1072–1079.  [23] Becker S., Pflugbeil C., Gröger M., Canis M., Ledderose G.J.,  Kramer M.F. Olfactory dysfunction in seasonal and perennial allergic  rhinitis. Acta Otolaryngol. 2012;132:763–768.  [24] Simola M., Malmberg H. Sense of smell in allergic and nonallergic  rhinitis. Allergy. 1998;53:190–194.  [25] Smith W.M., Davidson T.M., Murphy C. Toxin-induced chemosen-  sory dysfunction: a case series and review. Am. J. Rhinol. Allergy.  2009;23:578–581.  [26] Gupta R.S., Warren C.M., Smith B.M., Jiang J., Blumenstock J.A.,  Davis M.M., Schleimer R.P., Nadeau K.C. Prevalence and severity of  food allergies among US adults. JAMA Netw. Open. 2019;2:e185630.  [27] Seite S., Kuo A.M., Taieb C., Strugar T.L., Lio P. Self-reported preva-  lence of allergies in the USA and impact on skin-an epidemiological  study on a representative sample of american adults. Int. J. Environ.  Res. Public Health. 2020;17.  [28] Salo P.M., Arbes Jr. S.J., Jaramillo R., Calatroni A., Weir C.H., Sever  M.L., Hoppin J.A., Rose K.M., Liu A.H., Gergen P.J., Mitchell H.E.,  Zeldin D.C. Prevalence of allergic sensitization in the United States: re-  sults from the National Health and Nutrition Examination Survey  (NHANES) 2005-2006. J. Allergy Clin. Immunol. 2014;134:350–359.  [29] Veldhuizen M.G., Shepard T.G., Wang M.F., Marks L.E. Coacti-  vation of gustatory and olfactory signals in flavor perception. Chem.  Senses. 2010;35:121–133.  [30] Hopkins C., Kelly C. Prevalence and persistence of smell and taste  dysfunction in COVID-19; how should dental practices apply diagnostic  criteria?. BDJ In Practice. 2021;34:22–23.  [31] Bramerson A., Johansson L., Ek L., Nordin S., Bende M. Prevalence  of

olfactory

dysfunction:

the

skovde

population-based

study. 

Laryngoscope. 2004;114:733–737.  [32] Grange J.M., Stanford J.L., Rook G.A., Wright P. Role of viral infec-  tions in the inception of childhood asthma and allergies. Thorax.  1995;50:701.  [33] Martinez F.D. Role of viral infections in the inception of asthma  and allergies during childhood: could they be protective?. Thorax. 

366

1994;49:1189–1191.  [34] Skoner D.P. Viral infection and allergy: lower airway. Allergy Asth-  ma Proc. 2002;23:229–232. [35] Xepapadaki P., Papadopoulos N.G. Viral infections and allergies.  Immunobiology. 2007;212:453–459.  [36] Tantilipikorn P., Auewarakul P. Airway allergy and viral infection.  Asian Pac. J. Allergy Immunol. 2011;29:113–119.  [37] Reinhardt R. Blunting the synergistic effect of viral infections and  allergies—IgE testing for at-risk asthma patients. MLO Med. Lab. Obs.  2011;43: 10-12, 14, 16; quiz 20-11.  [38] Borowsky B., Adham N., Jones K.A., Raddatz R., Artymyshyn R.,  Ogozalek K.L., Durkin M.M., Lakhlani P.P., Bonini J.A., Pathirana S.,  Boyle N., Pu X., Kouranova E., Lichtblau H., Ochoa F.Y., Branchek T.A.,  Gerald C. Trace amines: identification of a family of mammalian G pro-  tein-cou-pled receptors. Proc. Natl. Acad. Sci. U. S. A. 2001;98:8966–  8971.  [39] Schwartz M.D., Palmerston J.B., Lee D.L., Hoener M.C., Kilduff T.S.  Deletion of trace amine-associated receptor 1 attenuates behavioral re-  sponses to caffeine. Front. Pharmacol. 2018;9:35.  [40] Liberles S.D., Buck L.B. A second class of chemosensory receptors  in the olfactory epithelium. Nature. 2006;442:645–650.  [41] Espinoza S., Sukhanov I., Efimova E.V., Kozlova A., Antonova K.A.,  Illiano P., Leo D., Merkulyeva N., Kalinina D., Musienko P., Rocchi A.,  Mus L., Sotnikova T.D., Gainetdinov R.R. Trace amine-associated  receptor 5 provides olfactory input into limbic brain areas and modu-  lates emotional behaviors and serotonin transmission. Front. Mol.  Neurosci. 2020;13:18.  [42] Frascarelli S., Ghelardoni S., Chiellini G., Vargiu R., Ronca-Testoni  S., Scanlan T.S., Grandy D.K., Zucchi R. Cardiac effects of trace amines:  pharmacological characterization of trace amine-associated receptors.  Eur. J. Pharmacol. 2008;587:231–236.  [43] Ito J., Ito M., Nambu H., Fujikawa T., Tanaka K., Iwaasa H., Tokita  S. Anatomical and histological profiling of orphan G-protein-coupled  receptor expression in gastrointestinal tract of C57BL/6J mice. Cell Tis-  sue Res. 2009;338:257–269.  [44] Bugda Gwilt K., Olliffe N., Hoffing R.A., Miller G.M. Trace amine 

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associated receptor 1 (TAAR1) expression and modulation of inflam-  matory

cytokine

production

in

mouse

bone

marrow-derived 

macrophages: a novel mechanism for inflammation in ulcerative  colitis. Immunopharmacol. Immunotoxicol. 2019;41:577–585.  [45] Gwilt K.B., Olliffe N., Hoffing R., Westmoreland S., Schueler A.,  Miller G. P132 Dextran sulfate sodium-induced colitis is attenuated in  trace amine associated receptor 1 knockout mice. Inflamm. Bowel Dis.  2019;25:S63.  [46] Szumska J., Qatato M., Rehders M., Fuhrer D., Biebermann H., Grandy D.K., Kohrle J., Brix K. Trace amine-associated receptor 1 local-  ization at the apical plasma membrane domain of fisher rat thyroid ep-  ithelial cells is confined to cilia. Eur. Thyroid J. 2015;4:30–41. 

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  Chapter 12: Microorganisms producing biogenic amines: From food to  human body 

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Abstract  Exposure to tryptamine leads to different effects including concen-  tration-depen-dent cytotoxicity in microorganisms and in mammals.  Tryptamine promotes dysbiosis. Furthermore, we demonstrated that  tryptamine-induced vesicle formation in cytoplasm and in mito-  chondria. The generation of vesicles is a constitutive attribute of mito-  chondria inherited from bacterial ancestors. Previously, Paley reviewed  the data on the presence of biogenic amine tryptamine and other bio-  genic amines (BA) in food products, in different microorganisms and  in human body. This chapter includes a further analysis of the data on  tryptamine and other BA in food such as sausages, different cheese  varieties, honey, yogurt and microorganisms such as fungal pathogen  Fusarium graminearum, and bacteria Streptococcus thermophilus used in  dairy industry with a focus on possible origin of some microorganisms  producing BA in humans.   

Keywords    Fungal pathogen; Fusarium graminearum; Streptococcus thermophiles; Dys-  biosis; Food; Honey; Yogurt; Bread; Lymphoblastic leukemia; Bacter-  aemia; Large bowel pathology 

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1: Sausages, different cheese varieties, honey, yogurt  Exposure to tryptamine leads to different effects including concentration-  dependent cytotoxicity in microorganisms and in mammals. Tryptamine  promotes dysbiosis. Particularly, aromatic amino acid-derived compounds  including tryptamine induce morphological changes and modulate the cell  growth of wine yeast species [1]. Furthermore, we demonstrated the  tryptamine-induced vesicle formation in cytoplasm and in mitochondria  (Paley, Perry, Sokolova, 2013) [2]. The generation of vesicles is a constitutive  attribute of mitochondria inherited from bacterial ancestors (Popov, 2022)  [3]. The physiological conditions and mild oxidative stress promote oxida-  tion and dysfunction of certain proteins and lipids within the mitochondrial  membranes; these constituents are subsequently packed as small mito-  chondrial-de-rived vesicles (MDVs) (70–150 nm in diameter) and are trans-  ported intracellularly to lysosomes and peroxisomes to be degraded or  transported extracellularly.  Previously, Paley [4–6] reviewed the data on the presence of biogenic  amine tryptamine and other biogenic amines (BA) in food products, in dif-  ferent microorganisms and in human body. This chapter includes a further  analysis of the data on tryptamine and other BA in food, microorganisms,  and in human body with a focus on possible origin of some micro-  organisms producing BA in humans.  In study by Bruna et al (2003), the mold strain of Penicillium camemberti  was superficially inoculated on fermented sausages in an attempt to im-  prove their sensory properties [7]. The growth of this mold on the surface of  the sausages resulted in an intense proteolysis and lipolysis, which caused  an increase in the concentration of free amino acids, free fatty acids, and  volatile compounds. The development of the fungal mycelia on the surface  of the sausages also resulted in increase of BA including tryptamine (signif-  icantly different, P  T, p.(Arg186Ter) and a deletion of  exon 13–17 in RBL2 (NM_005611.3), establishing RBL2 as a candidate gene  for an autosomal recessive neurodevelopmental disorder [193]. Tryptamine  upregulates (2.23-fold) the apoptotic protease activating factor 1 (Apaf1)  [191]. Apaf1 is the molecular core of the apoptosome, a multiprotein com-  plex mediating the so-called mitochondrial pathway of cell death. Feraro and  colleagues (2003) discussed some evidences regarding the putative role of the apoptosome in neurodegeneration and cancer [194]. The researchers  showed that physiological concentrations of tryptamine lead to induction of  cytochrome P4501A1 (CYP1A1) transcription through an AhR-dependent  mechanism [191]. CYP1A1 mRNA induction by tryptamine is diminished by  inhibiting MAO. To verify the involvement of MAO enzymes in the  tryptamine-dependent induction of CYP1A1, the authors used the irreversible  MAO inhibitor Phenelzine known to target both MAO isoforms, as well as  siRNA constructs directed toward MAOA and MAOB, to reduce the activity  of MAO. The authors suggest that tryptamine acts as an AhR proligand pos-  sibly by converting to a high-affinity AhR ligand [191]. However, more than  50% of tryptamine-upregulated transcripts (12 of 22 identified) were not af-  fected by a putative tryptamine metabolite in the same study by Vikstrom  Bergander et al.  Furthermore, tyramine is a regulator of MAO-A gene operon in bacteria  [195]. The K. aerogenes gene maoA, which is involved in the synthesis of MAO, was induced by tyramine and the related compounds in the study by  Sugino and colleagues (1992) [195].  Heli Elovaara and colleagues from University of Turku, Finland (2015)  demonstrated that primary amine oxidase of Escherichia coli is a metabolic  enzyme that can use a human leukocyte molecule as a substrate [196]. Es-  cherichia coli amine oxidase (ECAO), encoded by the tynA gene, catalyzes the  oxidative deamination of aromatic amines into aldehydes through a well-  established mechanism, but its exact biological role was unknown. The au-  thors investigated the role of ECAO by screening environmental and human  isolates for tynA and characterizing a tynA-deletion strain using microarray  analysis and biochemical studies. The presence of tynA did not correlate  with pathogenicity. In tynA+ Escherichia coli strains, ECAO-enabled bacterial  growth in phenylethylamine (PEA), and the resultant H O was released  2 2

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into the growth medium. Some aminoglycoside antibiotics inhibited the  enzymatic activity of ECAO, which could affect the growth of tynA+ bacteria.  The results suggest that tynA is a reserve gene used under stringent environ-  mental conditions in which ECAO may, due to its production of H O , pro-  2 2 vide a growth advantage over other bacteria that are unable to manage high  levels of this oxidant. In addition, ECAO, which resembles the human ho-  molog hAOC3, is able to process an unknown substrate on human leuko-  cytes [196]. In Escherichia coli, a copper amine oxidase (ECAO) is encoded by  the tynA gene (Entrez Gene ID: 945939, previously known as maoA). ECAO  is a soluble, periplasmic, homodimeric protein with one copper ion and  posttranslationally derived topaquinones at both of its active sites [3]. Aro-  matic amines are the preferred substrates of ECAO, as compared to aliphat-  ic amines and polyamines; therefore, it is also called 2-phenylethylamine  (PEA) oxidase or tyramine oxidase. The existence of tynA in different Es-  cherichia coli strains was assayed first by screening 38 Finnish waste water  and well water samples for the presence of tynA using PCR. More than half  of the well water samples (57%) and about one-third of the wastewater sam-  ples (35%) were tynA+. The subsequent screening of different human iso-  lates and Escherichia coli pathotypes indicated that this gene could be fre-  quently detected in diarrhea-causing pathotypes, such as non-O157: H7  EHECs (82% tynA+), enterotoxigenic Escherichia coli (ETEC; 69%), and en-  teroinvasive Escherichia coli (EIEC; 67%), as well as in fecal isolates (38%. Of  note, tynA was less frequently detected in enteropathogenic Escherichia coli  (EPEC; 17%). Among extraintestinal pathogenic isolates, tynA was most fre-  quently detected in sepsis isolates (27%). Out of the few tested pus (7),  wound (3), and blood (8) samples, 71%, 67%, and 50% were tynA+, respec-  tively. The tynA screening was negative in newborn meningitis (11) and in  O157:H7 EHEC (28) isolates. ECAO preferentially processes aromatic amine  substrates such as PEA, tyramine, and tryptamine, whereas the human ho-  molog of ECAO, hAOC3, is most active toward benzylamine (BA) and  methylamine [196]. Among seven different inhibitor concentrations (0.1–  10 μM), the authors observed a half maximal inhibitory concentration  (IC50). ECAO is able to use human granulocytes as a substrate. As a  semicarbazide-sensitive amine oxidase, ECAO is able to process PEA, tyra-  mine, and tryptamine, and its activity is inhibited by semicarbazide (SC), hy-  droxylamine, phenelzine, iproniazid, and tranylcypromine [196]. 

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Escherichia coli was detected in tumors in a number of studies analyzed by  Trudy M. Wassenaar (2018) in the critical review article on Escherichia coli  and colorectal cancer [197].  Hence, tryptamine and tyramine can upregulate MAO and thus stimulate  their own oxidation. The bacterial semicarbazide-sensitive amine oxidase (Escherichia coli) catalyzing oxidation of PEA, tyramine, and tryptamine  presents in human isolates and the tynA+ bacteria may be present in human  tumors thus leading to the decrease or elimination of the anticancer  tryptamine.  Therefore, breast cancer is associated with rosacea in the United States,  southern China, and in Denmark. Breast cancer was found to be related to  microbiome dysbiosis. The high MAO-A expression can be responsible for  the reduction of antiproliferative metabolite tryptamine in tumors. A low  MAO-A activity in brain can be responsible for neurotoxicity of tryptamine  that readily cross the blood-brain barrier. The bacterial amine oxidase gene  was found in human tissues.  The combination of bacteria-producing tryptamine, for instance Staphy-  lococcus epidermis and bacteria possessing amine-inducible amine oxidase  such as Escherichia coli can lead in tryptamine level fluctuations as I mod-  eled and described earlier for SH-SY5Y neuroblastoma cell line containing  different morphological cell variants with the different sensitivities and fates  toward tryptamine. These tryptamine fluctuations can lead to cell death, cell  proliferation, and cell differentiation depending on cell type, phase of devel-  opment (stage of differentiation), and the pattern of tryptamine content fluc-  tuations leading to cell inhibition or relaxation (1999, 2011) [98,141]. Human  neuroblastoma arises from the developing neural crest. Long-term studies  have shown the presence in human neuroblastoma cell lines of three dis-  tinct cell types: I-type stem cells, N-type neuroblastic/neuroendocrine pre-  cursors, and S-type Schwannian/melanoblastic precursors as reported by  Robert A Ross, June L Biedler, Barbara A Spengler (2003) [198]. These dis-  tinct cell types can differentiate predictably along specific neural crest lin-  eages in response to particular morphogens. As assessed by tumor forma-  tion in nude mice and anchorage-independent growth in soft agar, I-type  stem cells are significantly more malignant than either N- or S-type cells. Re-  cent research shows that three similar cell types are also present in human  neuroblastoma

tumors.

Using

immunocytochemical,

laser-capture

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microdissection, or short-term culture methods to identify cell types in tu-  mors of different stages and/or different outcomes, these studies have  shown that (1) all tumors contain neuroblasts in various differentiation  states; (2) presumptive I-type stem cells are present in tumors of all stages;  and (3) stromal cells may be tumor-derived, i.e., S-type cells, as well as of  normal origin. More importantly, there is a higher incidence of I-type cells in  tumors that progress, consistent with the high malignant potential of this  cell type in vitro [198].  I (Paley, 2011) [141] reveled the additional cell type in SH-SY5Y neurob-  lastoma cell line, the tryptamine-resistant satellite progenitor cells tightly at-  tached to epithelioid cells. The satellite cells can start division and growth of  highly malignant neuroblasts. A fraction of epithelioids was adhered to  satellite cells via trypsin-resistant interdigitating junctions demonstrating  cell-cell adhesion that under light microscopy look like internalized small  progenitor cells within epithelial cells [141]. Tryptamine stimulated the satel-  lite division and differentiation into neurons, transitional cell variants, and  neuroblasts able to repopulate [141]. Nemecek and colleagues (1986) pub-  lished in Proc Natl Acad Sci U S A that serotonin and tryptamine at low con-  centrations stimulate mitosis [199]. Bovine aortic smooth muscle cells in  vitro responded to 1 nM to 10 μM serotonin with increased incorporation  of [3H]thymidine into DNA. Tryptamine was approximately 1/10th as potent  as serotonin as a mitogen for smooth muscle cells. Other indoles that are  structurally related to serotonin (d- and l-tryptophan, 5-hydroxy-l-tryptophan,  N-acetyl-5-hydroxytryptamine, melatonin, 5-hydroxyindoleacetic acid, and 5-  hydroxytryptophol) and quipazine were inactive [199]. Because of the tight  attachment to other neuroblastoma cell variants the satellite cells could es-  cape separation during cell cloning and/or satellite cells are the reserve cells  surviving the harsh conditions. Morphologically similar “basal” and “re-  serve” cells in oviductal were described in the cervical epithelium in man by  Peters (1986) [200]. JASON C. Mills and Sansom published a review article  in Science Signaling (2015) [201] regarding increasing awareness that the  canonical models of terminal differentiation need reevaluation. First, it be-  came clear that adult mammalian cells could be dedifferentiated in culture  into pluripotent cells, demonstrating the plasticity of adult cells. Now, it is  evident that mature epithelial cells can also reprogram in vivo to contribute  to repair or regeneration and, aberrantly, to cancer. This review compares 

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three GI epithelial tissues (pancreas, intestine, and stomach) to draw in-  sights into the molecular basis of reprogramming as a basic cellular  process, akin to mitosis or apoptosis, and to highlight potential functional  and dysfunctional roles reprogramming cells play in tissues [201].  Raschella and colleagues (1998) [202] reported on the retinoblastoma  family of nuclear factors RB, the prototype of the tumor suppressor genes  and of the strictly related genes p107 and Rb2/p130. The authors determined  the expression and the phosphorylation of the RB family gene products dur-  ing the DMSO-induced differentiation of the N1E-115 murine neuroblastoma  cells. In this system, pRb2/p130 was strongly upregulated during mid-late  differentiation stages. Transfection of each of the RB family genes in these  cells was able, at different degrees, to induce neuronal differentiation, to in-  hibit [3H]thymidine incorporation, and to downregulate the activity of the  B-myb promoter [202]. The pRb2-containing genomic region, i.e., the long  arm of chromosome 16, is often lost in carcinomas of the breast, prostate,  liver, and ovary [203]. Importantly, tryptamine upregulates transcription of  RBL2/p130 [191], a protein inducing neurodifferention [202] while tryptamine  induce neurodifferentiation of human neuroblastoma cells [98,141]. Thus,  tryptamine can affect the neuroblastoma cell variants via upregulation of  RBL2 / RB2 p130.  Dermatologic manifestations of internal cancer were described and illus-  trated by Thiers (1986) [204].  Therefore, tryptamine can initiate mitosis or apoptosis and plays potential  functional and dysfunctional roles in reprogramming cells in tissues. 

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8: Rosacea and acne  The microbiome plays an important role in a wide variety of skin disorders.  Not only is the skin microbiome altered but also surprisingly many skin dis-  eases are accompanied by an altered gut microbiome (De Pessemier and  colleagues, 2021) [205].  Acne rosacea (rosacea) and acne vulgaris (acne) are two commonly seen  rashes that affect face.  Acne vulgaris, commonly termed acne, is an extremely common disease.  It can be found in nearly all teenagers to some degree as well as in women  in their 30s. When combined with other adolescent tensions, acne can be a  difficult disease to treat. Rosacea, which usually starts in the late 20s, may  affect the eyes as well as the skin. This article describes the pathogenesis of  acne and rosacea and treatment approaches the primary care physician can  use (Webster, 2001) [206].  Thompson and colleagues (2021) reported that acne and rosacea, despite  their similar clinical presentations, follow distinct clinical courses, sug-  gesting that fundamental differences exist in their pathophysiology. The re-  searchers performed a case-control study profiling the skin microbiota in  rosacea and acne patients compared to matched controls. Nineteen rosacea  and eight acne patients were matched to controls by age ±5 years, sex, and  race. DNA was extracted from facial skin swabs. The V3V4 region of the  bacterial 16S rRNA gene was sequenced using Illumina MiSeq and analyzed  using QIIME/Metastats 2.0 software. The mean relative abundance of  Cutibacterium acnes (Propionibacterium acnes, recently renamed Cutibac-  terium acnes) in rosacea with inflammatory papules and pustules (20.454%  ±16.943%) was more similar to that of acne (19.055% ±15.469%) than that  of rosacea without inflammatory papules and pustules (30.419% ±21.862%).  Cutibacterium acnes (P = .048) and Serratia marcescens (P = .038) were  significantly enriched in individuals with rosacea compared to acne [207].  Setsuko Nishijima and colleagues (2000) [208] reported the article on the  bacteriology of acne vulgaris and antimicrobial susceptibility of Propioni-  bacterium acnes and Staphylococcus epidermidis isolated from acne lesions.  The researchers examined the species of bacteria aerobically and anaero-  bically isolated from 30 acne lesions and determined antimicrobial suscepti-  bilities of Propionibacterium acnes and Staphylococcus epidermidis using nine  antimicrobial

agents.

Among

the

bacteria

isolated,

Staphylococcus 

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epidermidis was most dominant. Both Propionibacterium acnes and Staphy-  lococcus epidermidis were isolated from half of the acne lesions. The min-  imum inhibitory concentration (MIC) of seven antimicrobials (ampicillin,  erythromycin, roxithromycin, clindamycin, tetracycline, minocycline, and  nadifloxacin) against Propionibacterium acnes was under 3.13 μg/mL. There  were very few resistant strains of Propionibacterium acnes, but many of  Staphylococcus epidermidis. More than 30% of the Staphylococcus epidermidis  isolates were resistant to erythromycin, roxithromycin, and clindamycin.  After long-term systemic antibiotic therapy, the resistant strains of Staphy-  lococcus epidermidis increased, but Propionibacterium acnes resistance was  still limited. It should be noted that both Propionibacterium acnes and  Staphylococcus epidermidis in the acne lesions may acquire resistance to an-  timicrobials [208]. Study by Christensen and colleagues (2016) suggests  that interspecies interactions could potentially jeopardize balances in the  skin microbiota. In particular, Staphylococcus epidermidis strains possess an  arsenal of different mechanisms to inhibit Propionibacterium acnes. How-  ever, if such interactions are relevant in skin disorders such as acne vulgaris  remains questionable, since no difference in the antimicrobial activity  against, or the sensitivity toward Staphylococcus epidermidis could be de-  tected between health- and acne-associated strains of Propionibacterium  acnes [209]. In this study [209], the bacterial isolates, 77 and 24 strains for  Propionibacterium acnes and Staphylococcus epidermidis, respectively, were  previously obtained by swab sampling from human skin of acne patients  and healthy individuals (Lomholt and Kilian, 2010) [210].  Therefore, Staphylococcus epidermidis was detected in both the pustules of  rosacea [15] and in the acne lesions [208].  Dobson and Belknap (1980) [211] reported results of the multiclinic dou-  ble-blind trial, in which 253 patients with moderate to severe acne vulgaris  were treated with erythromycin, 1.5% topical solution (n = 127), or the vehi-  cle (n = 126). The preparations were applied twice daily for 12 weeks. The  response to treatment was evaluated by lesion counts and overall clinical  judgment at 2, 4, 8, 10, and 12 weeks after initiation of treatment. The  reduction in the number of inflammatory lesions, papules, and pustules was  significantly greater (P  li-caine > prilo- (Yasuhara and colleagues from De-  partment of Pharmacology, School of Medicine, Showa University, Japan,  1982) [248]. Haque and Poddar (1984) [249] examined effect of lignocaine  (synonym of lidocaine) on MAO activity of brain and liver. Lignocaine (2–  20 mM) inhibits (in vitro) both brain and liver mitochondrial MAO activity,  using tyramine, serotonin, and benzylamine as substrates, in a concen-  tration-depen-dent manner. Furthermore, lignocaine produces a marked in  vitro inhibition of serotonin and tyramine oxidation in MAO-A and not in  MAO-B preparation of rat brain [249]. Heavner, Gertsch, and Rosenberg 

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from Texas Tech University Health Sciences Center, Lubbock, Texas, United  States (1986) compared the MAO inhibitory potency of some commonly  used local anesthetics by the examination of their selectivity for two forms  of MAO (MAO-A and MAO-B). The effects of tetracaine, bupivacaine, lido-  caine, and mepivacaine on kynuramine oxidation in rat and mouse ho-  mogenates were tested. The effects of bupivacaine, tetracaine, and lidocaine  on spinal cord MAO activity and the effects of clorgyline and pargyline,  selective MAO-A and MAO-B inhibitors, respectively, were also tested.  Tetracaine was by far the most potent inhibitor of both types of MAO; the  IC50 was 0.3 μM (90 ng/mL) for MAO-A and 5.2 μM (1.56 μg/mL) for  MAO-B. All amide local anesthetics caused a 50% inhibition (IC50) of  MAO-A and MAO-B at about 1000 times higher concentrations. Tetracaine,  lidocaine, and mepivacaine were more potent inhibitors of MAO-A than of  MAO-B, whereas bupivacaine and etidocaine exhibited some preference for  MAO-B. Spinal cord MAO was identified as type B and was very sensitive to  inhibition by tetracaine (IC50 = 4.3 μM; 1.29 μg/mL). Bupivacaine and  lidocaine were weaker inhibitors, with a 30% inhibition produced by the  highest concentrations tested (2  mM (648  μg/mL) bupivacaine and  10 mM (2.7 mg/mL) lidocaine. The authors concluded that results of this  study support the hypothesis that tetracaine and perhaps other ester-linked  local anesthetics may produce analgesia by affecting the turnover of  monoamines associated with the endogenous pain control system via inhi-  bition of spinal cord MAO [250].  Notably, tryptamine was shown to be hyperalgesic—abnormally height-  ened sensitivity to pain or analgesic—acting to relieve pain in a concen-  tration-depen-dent manner. Specifically, in the study by Larson, tryptamine  was applied directly into the spinal subarachnoid space of rats via perma-  nently indwelling cannulas examine the pain perception (Larson, 1983) [251].  Changes in pain perception were measured by changes in the latency of the  tail flick in response to a radiant heat source of low intensity. While an in-  trathecal injection of serotonin has been previously shown to be analgesic,  exogenous tryptamine produced dual effects on the pain threshold, depend-  ing on the dose of tryptamine injected. Low doses of tryptamine (100 and  200 μg/rat) injected intrathecally onto the sacral area of the spinal cord ap-  peared to be hyperalgesic by significantly decreasing the average tail-flick la-  tency by 5 min after injection. Administration of the serotonin antagonist 

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methysergide alone was without effect on the average tail-flick reaction time  when injected either intrathecally or subcutaneously. However, pretreatment  with either methysergide or cinanserin not only failed to inhibit tryptamine’s  potentiation of nociception (perception of panful or injurious stimulus), but  actually enhanced the hyperalgesia produced by tryptamine. In contrast, a  dose of 400 μg of tryptamine significantly increased the average tail-flick la-  tency, suggesting an analgesic effect at this higher dose. This analgesic ef-  fect of 400 μg of tryptamine was completely inhibited by subcutaneously  administered methysergide, while intrathecally injected methysergide pro-  duced even greater decreases in the tail-flick latencies after this high dose of  tryptamine. These results suggest that tryptamine, although it differs from  serotonin by only one hydroxyl group, may play a role in nociception which  is opposite that played by serotonin [251]. Nevertheless, synergistic behav-  ioral effects of serotonin and tryptamine injected intrathecally in mice were  demonstrated by Larson and Wilcox (1984) [252].  Thus, lidocaine, the one of the most commonly used local anesthetics in  dentistry, is able to induce (1) the skin manifestations similar to those ob-  served in Rosacea, (2) dysbiosis, (3) bacterial translocation, and (4) in-  crease in biogenic amines via MAO inhibition.  For the past 4 years of his life, TV actor Peter Falk, who died in June 2011  aged 83, suffered from severe AD. Yet at the beginning of 2007 he was still  intellectually sharp enough to be working. But within weeks he “rapidly  slipped into dementia after a series of dental operations,” according to his  own doctor [253]. Role of infection in the pathogenesis of AD is suggested  [254,255]. 

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10: Demodex: Hordeola and cancer  Chalazia and hordeola (styes) are sudden-onset localized swellings of the  eyelid. A chalazion is caused by noninfectious meibomian gland occlusion,  whereas a hordeolum usually is caused by infection. Both conditions ini-  tially cause eyelid hyperemia, edema, and swelling (James Garrity of Mayo  Clinic College of Medicine and Science, 2020) [256].  The retrospective, matched control, longitudinal study examined the rela-  tionship between childhood stye and adult rosacea (Bamford and col-  leagues, 2006) [257]. The records of the Rochester Epidemiology Project  were examined to identify patients who received care for stye or blepharitis  between ages 2 and 17 years and received care for any cause at age  40 years or older. Patients were matched by group to control subjects (1:2).  Patients with stye during childhood (N = 201) had a higher prevalence of  adult rosacea than did control subjects (5.5% vs 1.5%, P = .01). Patients  who had other childhood eye conditions without stye (N = 504) were not at  higher risk. The association between childhood stye and adult rosacea ap-  pears to be significant and should be examined further [257].  Demodex mites, class Arachnida and subclass Acarina, are elongated  mites with clear cephalothorax and abdomens, the former with four pairs of  legs (Lacey and colleagues of University of Ireland Maynooth, 2009) [258].  There are more than 100 species of Demodex mite, many of which are oblig-  atory commensals of the pilosebaceous unit of mammals including cats,  dogs, sheep, cattle, pigs, goats, deer, bats, hamsters, rats, and mice. Among  them, Demodex canis, which is found ubiquitously in dogs, is the most  documented and investigated. In excessive numbers D. canis causes the in-  flammatory disease termed demodicosis (demodectic mange, follicular  mange or red mange), which is more common in purebred dogs and has a  hereditary predisposition in breeding kennels. Two distinct Demodex species  have been confirmed as the most common ectoparasite in man. The larger  D. folliculorum, about 0.3–0.4 mm long, is primarily found as a cluster in  the hair follicle, while the smaller D. brevis, about 0.2–0.3 mm long with a  spindle shape and stubby legs, resides solitarily in the sebaceous gland.  These two species are also ubiquitously found in all human races without  gender preference. The pathogenic role of Demodex mites in veterinary  medicine is not as greatly disputed as in human diseases. The pathogenic  potential of the two mites causing inflammatory diseases of human skin and 

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eye discussed [258]. Although Demodex mites have been implicated as a  cause of many human skin disorders, their pathogenic role has long been  debated. Such a concern has been raised in part because some Demodex  mites can be found in the skin of asymptomatic individuals. Most re-  searchers attribute some skin diseases to Demodex only when their numbers  are elevated. D. folliculorum is resistant to a wide range of common anti-  septic solutions including 75% alcohol and 10% povidone-iodine, but can  dose dependently be killed by tea tree oil (TTO). TTO, a natural essential oil  steam-distilled from the leaf of the tea tree Melaleuca alternifolia, has long  been used as an aboriginal traditional medicine in Australia for wounds and  cutaneous infection. The authors summarized the evidences to demonstrate  the life of Demodex mites in several common human diseases (Lacey, Ka-  vanagh, Tseng, 2009) [258].  Gao and colleagues of Miami, Florida, United States (2005) reported the  conditions for in vitro and in vivo killing of ocular Demodex by TTO [259].  The organism D. folliculorum is found in the eyelash follicle and D. brevis  burrows deep in sebaceous and meibomian glands. Although their patho-  genic role remains unsettled, efforts have been made to eradicate ocular De-  modex in patients presenting with blepharitis. Survival time of Demodex was  measured under the microscope. D. folliculorum survived for more than  150 min in 10% povidone‑iodine, 75% alcohol, 50% baby shampoo, and  4% pilocarpine. However, the survival time was significantly shortened to  within 15 min in 100% alcohol, 100% TTO, 100% caraway oil, or 100% dill weed oil. TTO’s in vitro killing effect was dose dependent. Lid scrub with  50% TTO, but not with 50% baby shampoo, can further stimulate Demodex  to move out to the skin. The Demodex count did not reach zero in any of the  seven patients receiving daily lid scrub with baby shampoo for 40–  350 days. In contrast, the Demodex count dropped to zero in seven of nine  patients receiving TTO scrub in 4 weeks without recurrence. Demodex is  resistant to a wide range of antiseptic solutions. Weekly lid scrub with 50%  TTO (TTO was diluted with mineral oil into different concentrations) and  daily lid scrub with tea tree shampoo is effective in eradicating ocular  Demodex[259].  Essential oils of different plants were used for the treatment of Demodex  (Oseka and Sedzikowska, 2014) [260]. Upon the investigation of respective  essential oils, their effectiveness proved to differ. Some oils caused rapid 

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mites death, in as little time as several or between 10 and 20 min, while for  others it took several hours or days. 50% TTO (mean survival rate—7 min),  sage oil (mean survival rate—7 min), and peppermint oil (mean survival  rate—11 min) were established to show an optimal effect [260]. Basing on  the analysis of the effectiveness and chemical composition of respective  essential oils, terpene content in essential oils is most probable to have a  lethal effect on Demodex mites [260]. Good efficacy of TTO against Demodex  sp. has been reported. However, some patients develop allergic reactions  and ocular irritation in the course of TTO treatment. Tests with essential oils  showed that salvia and peppermint oils rapidly kill Demodex, in 7 and  11 min, respectively. Salvia is known as a valuable herb and is used to treat  eye disease. Therefore, salvia essential oil could be an alternative treatment  for demodicosis (Sędzikowska and colleagues, 2015) [261]. The Demodex  infestation is widely spread among older people [262]. Approximately 84%  of the population aged 60 years was infected, whereas 100% of the popu-  lation aged over 70 years was infected. More than 84% of patients with eye  discomfort were infected with Demodex. This review summarizes the antide-  modex and side effects of certain botanical essential oils. The high efficacy  and low side effects of essential oils, such as TTO and its active ingredient  terpinen-4-oil, camphor oil, sage oil, peppermint oil, neem oil, clove oil,  make them good candidates for the treatment of mites (Huang and col-  leagues, 2021) [262].  Karabay and Çerman (2020) of Department of Dermatology and Venere-  ology, Faculty of Medicine, Bahçeşehir University, Istanbul, Turkey [263] re-  ported on Demodex mites. Demodex mites found on the skin of many  healthy individuals. Demodex mites in high densities are considered to play  a pathogenic role. Demodex mites were first reported by Jakup Henle in 1871,  and detailed descriptions and demonstrations of the pathogen were made in  the following years. The Demodex mite belongs to the family Demodicidae.  D. folliculorum and D. brevis are the two types of Demodex mites that are  present on human skin and follicles. Although this parasite may be found  on every area of human skin, the mite has a predilection for the facial area.  Demodex mites may be found on normal skin with a density of   .05). Demodex infestation rates were  significantly higher in patients than in controls (P = .001). Demodex infes-  tation rates were significantly higher in the rosacea group than in acne vul-  garis and seborrheic dermatitis groups and in controls (P  =  .001;  P = .024; P = .001, respectively). Demodex infestation was found to be sig-  nificantly higher in the acne vulgaris and seborrheic dermatitis groups than  in controls (P = .001 and P = .001, respectively). No difference was ob-  served between the acne vulgaris and seborrheic dermatitis groups in terms  of demodicosis (P = .294). The findings of this study emphasize that acne  vulgaris, rosacea, and seborrheic dermatitis are significantly associated with  Demodex infestation [263].  Proliferation of Demodex mites is associated with rosacea. Furthermore,  Demodex-associated bacteria were suggested to play a role in the patho-  genesis of rosacea. Murillo and colleagues (2014) analyzed Demodex micro-  biota in France [264]. Mites were collected by standardized skin surface  biopsies from patients with erythematotelangiectatic (ETR), papulopustular  (PPR) rosacea, or from control subjects. The microbiota from each mite was  characterized by 16S rRNA clone library approach. The 16S rRNA clone li-  brary consisted of 367 clones obtained from 73 extracts originating from 5  samples per study group (ETR, PPR or healthy subjects). A total of 86  species were identified with 36 as Demodex-specific microbiota. In the papu-  lopustular group, proportions of Proteobacteria and Firmicutes increased,  whereas proportion of Actinobacteria decreased. Based on these data the  authors suggested a new perspectives for diagnostic of rosacea (Murillo,  Aubert, Raoult of Aix Marseille Université, Marseille, France, 2014) [264].  Demodex is unlikely to be the only cutaneous microbiotic component  contributing to the disease rosacea. One study showed that although treat-  ment of rosacea with topical antidemodex cream (permethrin 5%) decreased demodex counts significantly, it was not superior to topical antibiotics 

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(metronidazole 0.75%) in improving rosacea, suggesting bacterial  pathogens may be involved. Demodex mites are suspected carriers of Bacil-  lus oleronius, proinflammatory, gram-negative bacteria that are susceptible to  many antibiotics commonly used to treat rosacea, including doxycycline  (Ellis and colleagues, 2019) [265]. Histamine production by Bacillus oleronius  isolated from a cooked fish paste Rihaakuru (from south of Maldives) was  detected by Naila and colleagues of New Zealand and United Kingdom  (2011) [266].  Jun and colleagues (2021) [267] evaluated the association between De-  modex infestation and recurrent hordeola and examined the clinical features  associated with these eyelid lesions in South Korea. Researchers reviewed  250 patients and divided them into the recurrent hordeolum (n = 153) and  control (n = 97) groups. Demodex infestation was detected by epilating eye-  lashes around the lesion/s and viewing them under a light microscope. Pa-  tient medical records and photographs were retrospectively analyzed to  identify the clinical characteristics of Demodex-associated recurrent horde-  ola. Demodex was detected in 91 (59.5%) and 17 (17.5%) patients in the  recurrent hordeolum and control groups (P