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Leclercq S.,Mcmaster Brain Body Institute At St Josephs Healthcare Hamilton | Leclercq S.,McMaster University | Forsythe P.,Mcmaster Brain Body Institute At St Josephs Healthcare Hamilton | Forsythe P.,McMaster University | And 2 more authors.
Canadian Journal of Psychiatry | Year: 2016

Gut bacteria strongly influence our metabolic, endocrine, immune, and both peripheral and central nervous systems. Microbiota do this directly and indirectly through their components, shed and secreted, ranging from fermented and digested dietary and host products to functionally active neurotransmitters including serotonin, dopamine, and γ-aminobutyric acid. Depression has been associated with enhanced levels of proinflammatory biomarkers and abnormal responses to stress. Posttraumatic stress disorder (PTSD) appears to be marked in addition by low cortisol responses, and these factors seem to predict and predispose individuals to develop PTSD after a traumatic event. Dysregulation of the immune system and of the hypothalamic-pituitary-adrenal axis observed in PTSD may reflect prior trauma exposure, especially early in life. Early life, including the prenatal period, is a critical time in rodents, and may well be for humans, for the functional and structural development of the immune and nervous systems. These, in turn, are likely shaped and programmed by gut and possibly other bacteria. Recent experimental and clinical data converge on the hypothesis that imbalanced gut microbiota in early life may have long-lasting immune and other physiologic effects that make individuals more susceptible to develop PTSD after a traumatic event and contribute to the disorder. This suggests that it may be possible to target abnormalities in these systems by manipulation of certain gut bacterial communities directly through supplementation or indirectly by dietary and other novel approaches. © The Author(s) 2016. Source

Bienenstock J.,Mcmaster Brain Body Institute At St Josephs Healthcare Hamilton | Bienenstock J.,McMaster University | Forsythe P.,Mcmaster Brain Body Institute At St Josephs Healthcare Hamilton | Forsythe P.,McMaster University | And 4 more authors.
International Dairy Journal | Year: 2010

There is increasing evidence that diet and the nutrients it contains, may affect the function of the enteric nervous and immune systems, which in turn may alter bacterial diversity and function, intestinal motility and physiology, regulation of inflammation and also affect cognitive brain functions such as memory and even some behaviours. © 2009 Elsevier Ltd. All rights reserved. Source

Al-Nedawi K.,McMaster University | Mian M.F.,Mcmaster Brain Body Institute At St Josephs Healthcare Hamilton | Hossain N.,Mcmaster Brain Body Institute At St Josephs Healthcare Hamilton | Karimi K.,McMaster University | And 10 more authors.
FASEB Journal | Year: 2015

Ingestion of a commensal bacteria, Lactobacillus rhamnosus JB-1, has potent immunoregulatory effects, and changes nerve-dependent colon migrating motor complexes (MMCs), enteric nerve function, and behavior. How these alterations occur is unknown. JB-1 microvesicles (MVs) are enriched for heat shock protein components such as chaperonin 60 heat-shock protein isolated from Escherichia coli (GroEL) and reproduce regulatory and neuronal effects in vitro and in vivo. Ingested labeled MVs were detected in murine Peyer's patch (PP) dendritic cells (DCs) within 18 h. After 3 d, PP and mesenteric lymph node DCs assumed a regulatory phenotype and increased functional regulatory CD4+25+Foxp3+ T cells. JB-1, MVs, and GroEL similarly induced phenotypic change in cocultured DCs via multiple pathways including C-type lectin receptors specific intercellular adhesion molecule-3 grabbing non-integrin-related 1 and Dectin-1, as well as TLR-2 and -9. JB-1 and MVs also decreased the amplitude of neuronally dependent MMCs in an ex vivo model of peristalsis. Gut epithelial, but not direct neuronal application of, MVs, replicated functional effects of JB-1 on in situ patch-clamped enteric neurons. GroEL and anti-TLR-2 were without effect in this system, suggesting the importance of epithelium neuron signaling and discrimination between pathways for bacteria-neuron and -immune communication. Together these results offer a mechanistic explanation of how Gram-positive commensals and probiotics may influence the host's immune and nervous systems. © FASEB. Source

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