Microbiota and host determinants of behavioural phenotype in maternally separated mice.

Early-life stress is a determinant of vulnerability to a variety of disorders that include dysfunction of the brain and gut. Here we exploit a model of early-life stress, maternal separation (MS) in mice, to investigate the role of the intestinal microbiota in the development of impaired gut function and altered behaviour later in life. Using germ-free and specific pathogen-free mice, we demonstrate that MS alters the hypothalamic-pituitary-adrenal axis and colonic cholinergic neural regulation in a microbiota-independent fashion.

Altered colonic function and microbiota profile in a mouse model of chronic depression.

Background: Depression often coexists with the irritable bowel syndrome (IBS) which is characterized by alterations in gut function. There is emerging evidence that the microbial composition (microbiota) of the gut is altered in IBS, but the basis for this is poorly understood. The aim of this study was to determine whether the induction of chronic depression results in changes in the colonic function and in its microbial community, and to explore underlying mechanisms.

The anxiolytic effect of Bifidobacterium longum NCC3001 involves vagal pathways for gut-brain communication.

Background: The probiotic Bifidobacterium longum NCC3001 normalizes anxiety-like behavior and hippocampal brain derived neurotrophic factor (BDNF) in mice with infectious colitis. Using a model of chemical colitis we test whether the anxiolytic effect of B. longum involves vagal integrity, and changes in neural cell function.

The intestinal microbiota affect central levels of brain-derived neurotropic factor and behavior in mice.

Background & Aims: Alterations in the microbial composition of the gastrointestinal tract (dysbiosis) are believed to contribute to inflammatory and functional bowel disorders and psychiatric comorbidities. We examined whether the intestinal microbiota affects behavior and brain biochemistry in mice.

Methods: Specific pathogen-free (SPF) BALB/c mice, with or without subdiaphragmatic vagotomy or chemical sympathectomy, or germ-free BALB/c mice received a mixture of nonabsorbable antimicrobials (neomycin, bacitracin, and pimaricin) in their drinking water for 7 days.

Adoptive transfer of macrophage from mice with depression-like behavior enhances susceptibility to colitis.

Background: Depression is common in patients with inflammatory bowel disease (IBD) but the pathway is not well understood. We examined whether the locus of susceptibility to colitis in mice with depression-like behavior (DLB) resides with the macrophage and implicates the vagus nerve.

Methods: Chronic colitis mimicking ulcerative colitis (UC) was induced by dextran sulfate sodium administered to C57BL/6-mice.