Stress-induced alterations in intestinal microflora (original) (raw)
Related papers
Influence of Stress on Faecal Carriage of Clostridium perfringens
Microbial Ecology in Health and Disease, 2002
A drastic change in a human 's way of life is known to lead to dramatic modi cations in intestinal microbial balance. The effects of mild stress of everyda y life have, however , been poorly investigated . In this study, we have attempted to assess whether nal written examinatio n stress modi es the faecal microbiota in healthy youn g adults. Diet was standardised and faeca l samples collected during two period s of 48 h each , the rst 6 weeks before and the second during the nal written examination. F aecal hydratio n as well as count s in total aerobes, anaerobes, enterobacteria, enterococci, Clostridium perfringens and bi dobacteria were determined. Bi dobacteria, enterococci and enterobacteria did not show any signi cant variation. A signi cant rise in C. perfringens count s was observed throughou t this examination period . It preceded the increase in faeca l hydration only observed after a change in diet. Since psychologica l stress is known to increase intestinal mucin release, C. perfringens overgrowt h might re ect a better adaptation to substrates provided by the stressed host.
The Potential Impact of Selected Bacterial Strains on the Stress Response
Healthcare, 2021
Introduction: The composition of the microbiome is subject to a variety of factors, such as eating behavior and the history of medical treatment. The interest in the impact of the microbiome on the stress response is mainly explained by the lack of development of new effective treatments for stress-related diseases. This scoping review aims to present the current state of research regarding the impact of bacterial strains in the gut on the stress response in humans in order to not only highlight these impacts but to also suggest potential intervention options. Methods: We included full-text articles on studies that: (a) were consistent with our research question; and (b) included the variable stress either using biomedical parameters such as cortisol or by examining the subjective stress level. Information from selected studies was synthesized from study designs and the main findings. Results: Seven studies were included, although they were heterogenous. The results of these studies...
BMC microbiology, 2014
The microbiota of the mammalian gastrointestinal (GI) tract consists of diverse populations of commensal bacteria that interact with host physiological function. Dysregulating these populations, through exogenous means such as antibiotics or dietary changes, can have adverse consequences on the health of the host. Studies from laboratories such as ours have demonstrated that exposure to psychological stressors disrupts the population profile of intestinal microbiota. To date, such studies have primarily focused on prolonged stressors (repeated across several days) and have assessed fecal bacterial populations. It is not known whether shorter stressors can also impact the microbiota, and whether colonic mucosa-associated populations can also be affected. The mucosa-associated microbiota exist in close proximity to elements of the host immune system and the two are tightly interrelated. Therefore, alterations in these populations should be emphasized. Additionally, stressors can induc...
Gut, 2006
Background and aim: Chronic psychological stress, including water avoidance stress (WAS), induces intestinal mucosal barrier dysfunction and impairs mucosal defences against luminal bacteria. The aim of this study was to determine the ability of a defined probiotic regimen to prevent WAS induced intestinal pathophysiology. Methods: Male rats were subjected to either WAS or sham stress for one hour per day for 10 consecutive days. Additional animals received seven days of Lactobacillus helveticus and L rhamnosus in the drinking water prior to stress and remained on these probiotics for the duration of the study. Rats were then sacrificed, intestinal segments assessed in Ussing chambers, and mesenteric lymph nodes cultured to determine bacterial translocation. Results: All animals remained healthy for the duration of the study. Chronic WAS induced excess ion secretion (elevated baseline short circuit current) and barrier dysfunction (increased conductance) in both the ileum and colon, associated with increased bacterial adhesion and penetration into surface epithelial cells. Approximately 70% of rats subjected to WAS had bacterial translocation to mesenteric lymph nodes while there was no bacterial translocation in controls. Probiotic pretreatment alone had no effect on intestinal barrier function. However, WAS induced increased ileal short circuit current was reduced with probiotics whereas there was no impact on altered conductance. Pretreatment of animals with probiotics also completely abrogated WAS induced bacterial adhesion and prevented translocation of bacteria to mesenteric lymph nodes. Conclusion: These findings indicate that probiotics can prevent chronic stress induced intestinal abnormalities and, thereby, exert beneficial effects in the intestinal tract.
Handling stress may confound murine gut microbiota studies
PeerJ, 2017
Accumulating evidence indicates interactions between human milk composition, particularly sugars (human milk oligosaccharides or HMO), the gut microbiota of human infants, and behavioral effects. Some HMO secreted in human milk are unable to be endogenously digested by the human infant but are able to be metabolized by certain species of gut microbiota, including Bifidobacterium longum subsp. infantis (B. infantis), a species sensitive to host stress (Bailey & Coe, 2004). Exposure to gut bacteria like B. infantisduring critical neurodevelopment windows in early life appears to have behavioral consequences; however, environmental, physical, and social stress during this period can also have behavioral and microbial consequences. While rodent models are a useful method for determining causal relationships between HMO, gut microbiota, and behavior, murine studies of gut microbiota usually employ oral gavage, a technique stressful to the mouse. Our aim was to develop a less-invasive tec...
The Role of Microbiota and Probiotics in Stress-Induced Gastrointestinal Damage
Current Molecular Medicine, 2008
Stress has a major impact on gut physiology and may affect the clinical course of gastro-intestinal diseases. In this review, we focus on the interaction between commensal gut microbiota and intestinal mucosa during stress and discuss the possibilities to counteract the deleterious effects of stress with probiotics. Normally, commensal microbes and their hosts benefit from a symbiotic relationship. Stress does, however, reduce the number of Lactobacilli, while on the contrary, an increased growth, epithelial adherence and mucosal uptake of gram-negative pathogens, e.g. E. coli and Pseudomonas, are seen. Moreover, intestinal bacteria have the ability to sense a stressed host and up-regulate their virulence factors when opportunity knocks. Probiotics are "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host", and mainly represented by Lactic Acid Bacteria. Probiotics can counteract stress-induced changes in intestinal barrier function, visceral sensitivity and gut motility. These effects are strain specific and mediated by direct bacterial-host cell interaction and/or via soluble factors. Mechanisms of action include competition with pathogens for essential nutrients, induction of epithelial heat-shock proteins, restoring of tight junction protein structure, up-regulation of mucin genes, secretion of defensins, and regulation of the NF B signalling pathway. In addition, the reduction of intestinal pain perception was shown to be mediated via cannabinoid receptors. Based on the studies reviewed here there is clearly a rationale for probiotic treatment in patients with stressrelated intestinal disorders. We are however far from being able to choose the precise combination of strains or bacterial components for each clinical setting.
Gut microbes, 2014
The commensal microbiota of the human gastrointestinal tract live in a largely stable community structure, assisting in host physiological and immunological functions. Changes to this structure can be injurious to the health of the host, a concept termed dysbiosis. Psychological stress is a factor that has been implicated in causing dysbiosis, and studies performed by our lab have shown that restraint stress can indeed shift the cecal microbiota structure as well as increase the severity of a colonic infection caused by Citrobacter rodentium. However, this study, like many others, have focused on fecal contents when examining the effect of dysbiosis-causing stimuli (e.g. psychological stress) upon the microbiota. Since the mucosa-associated microbiota have unique properties and functions that can act upon the host, it is important to understand how stressor exposure might affect this niche of bacteria. To begin to understand whether chronic restraint stress changes the mucosa-associ...
Biological, environmental, and psychological stress and the human gut microbiome in healthy adults
Scientific Reports, 2025
Emerging research suggests that the gut microbiome plays a crucial role in stress. We assess stress microbiome associations in two samples of healthy adults across three stress domains (perceived stress, stressful life events, and biological stress /Respiratory Sinus Arrhythmia; RSA). Study 1 (n = 62; mean-age = 37.3 years; 68% female) and Study 2 (n = 74; mean-age = 41.6 years; female only) measured RSA during laboratory stressors and used 16S rRNA pyrosequencing to classify gut microbial composition from fecal samples. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States was used to predict functional pathways of metagenomes. Results showed differences in beta diversity between high and low stressful life events groups across both studies. Study 1 revealed differences in beta diversity between high and low RSA groups. In Study 1, the low perceived stress group was higher in alpha diversity than the high perceived stress group. Levels of Clostridium were negatively associated with RSA in Study 1 and levels Escherichia/Shigella were positively associated with perceived stress in Study 2. Associations between microbial functional pathways (L-lysine production and formaldehyde absorption) and RSA are discussed. Findings suggest that certain features of the gut microbiome are differentially associated with each stress domain.
Lactobacillus rhamnosus strain JB-1 reverses restraint stress- induced gut dysmo lity
Background: Environmental stress a ects the gut with dysmo lity being a common consequence. Although a variety of microbes or molecules may prevent the dysmo l- ity, none reverse the dysmo lity. Methods: We have used a 1 hour restraint stress mouse model to test for treatment e ects of the neuroac ve microbe, L. rhamnosus JB-1TM. Mo lity of uid- lled ex vivo gut segments in a perfusion organ bath was recorded by video and migra ng motor complexes measured using spa otemporal maps of diameter changes. Key Results: Stress reduced jejunal and increased colonic propaga ng contrac le clus- ter veloci es and frequencies, while increasing contrac on amplitudes for both. Lumi- nal applica on of 10E8 cfu/mL JB-1 restored motor complex variables to unstressed levels within minutes of applica on. L. salivarius or Na.acetate had no treatment e ects, while Na.butyrate par ally reversed stress e ects on colonic frequency and amplitude. Na.propionate reversed the stress e ects for jejunum and colon except on jejunal amplitude. Conclusions & Inferences: Our ndings demonstrate, for the rst me, a poten al for certain bene cial microbes as treatment of stress-induced intes nal dysmo lity and that the mechanism for restora on of func on occurs within the intes ne via a rapid drug-like ac on on the enteric nervous system.
Current Opinion in Clinical Nutrition and Metabolic Care, 2005
Most literature that examines gut barrier function focuses on alterations in bacterial flora, changes in mucosal epithelium, or the integrity of the mucosal defenses. This review examines new concepts on the interaction between bacteria and the host, the complex relationships that serve to benefit both in times of health, and the alterations and responses that occur during illness.