Old Friends, immunoregulation, and stress resilience

Abstract

There is a considerable body of evidence indicating that chronic adverse experience, especially chronic psychosocial stress/trauma, represents a major risk factor for the development of many somatic and affective disorders, including inflammatory bowel disease (IBD) and posttraumatic stress disorder (PTSD). However, the mechanisms underlying the development of chronic stress-associated disorders are still in large part unknown, and current treatment and prevention strategies lack efficacy and reliability. A greater understanding of mechanisms involved in the development and persistence of chronic stress-induced disorders may lead to novel approaches to prevention and treatment of these disorders. In this review, we provide evidence indicating that increases in immune (re-)activity and inflammation, potentially promoted by a reduced exposure to immunoregulatory microorganisms (“Old Friends”) in today’s modern society, may be causal factors in mediating the vulnerability to development and persistence of stress-related pathologies. Moreover, we discuss strategies to increase immunoregulatory processes and attenuate inflammation, as for instance contact with immunoregulatory Old Friends, which appears to be a promising strategy to promote stress resilience and to prevent/treat chronic stress-related disorders.

WITHDRAWN: The secret behind peripheral inflammation and depression: The hypothalamus

“…In recent years, the importance of the HPA axis for the pathophysiology of various mood disorders such as depression [6][7][8] has been emphasized. Models that support the in uence of the HPA axis on depression postulate chronically dysregulated activation of the HPA axis, which is also associated with dysregulation of immune function [8][9][10][11] . Various animal studies have shown the relationship between depression and in ammation [12][13][14][15] .…”

Association of the Salivary Microbiome With Animal Contact During Early Life and Stress-Induced Immune Activation in Healthy Participants

“…Stress-related somatic and psychiatric disorders have been increasing in Western societies throughout the last decades (1,2), with urban areas being more affected than rural ones (3,4). Although the underlying mechanisms are not fully understood, recent studies promote the hypothesis that a compromised immunoregulatory capacity, due to diminished contact to microorganisms (i.e., "Old Friends") with which humans coevolved, might at least in part underlie the increased disease vulnerability of individuals living in urban compared with rural areas (5). Throughout human evolution, the interactions between the innate immune system and these ancestral microbiota promoted immunoregulation, as they were either part of host physiology (human microbiota), were harmless but inevitably contaminating air, food, and water (environmental microbiota), or were causing severe tissue damage when attacked by the host immune system (e.g., helminthic parasites) (6)(7)(8).…”

“…Throughout human evolution, the interactions between the innate immune system and these ancestral microbiota promoted immunoregulation, as they were either part of host physiology (human microbiota), were harmless but inevitably contaminating air, food, and water (environmental microbiota), or were causing severe tissue damage when attacked by the host immune system (e.g., helminthic parasites) (6)(7)(8). However, microbial biodiversity and, thus, overall contact with environmental and commensal microorganisms that were present during mammalian evolution and that play a role in setting up regulatory immune pathways, is progressively diminishing in high-income countries, particularly in urban areas (5,8). The latter is due to sanitation, drinking water treatment, excessive use of antibiotics, changes in diet, feeding of formula milk as a replacement for breast milk, increased caesarean section birth rates, as well as increased time spent within the built environment (6)(7)(8)(9)(10).…”

„Old Friends“, Immunregulation und Stressresilienz

“…A greater understanding of mechanisms involved in the development and persistence of chronic stress-induced disorders may lead to novel approaches to prevention and treatment of these disorders. In this two-part review, we summarize the theoretical background (Part 1) and underlying mechanisms (Part 2) that support the hypothesis that 1 Bei dem vorliegenden Artikel handelt es sich um die deutsche Übersetzung des im Journal Pflügers Archiv -European Journal of Physiology erschienen Artikels Langgartner und Kollegen, 2018 [1].…”