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The role of Bifidobacterium species and microbial metabolites such as short-chain fatty acids (SCFAs) and human milk oligosaccharides in controlling intestinal inflammation and the pathogenesis of obesity and type 1 diabetes (T1D) has been largely studied in recent years. This paper discusses the discovery of signature biomarkers for obesity and T1D based on data from a novel test for profiling several Bifidobacterium species, combined with metabolomic analysis. Through the NUTRISHIELD clinical study, a total of 98 children were recruited: 40 healthy controls, 40 type 1 diabetics, and 18 obese children. Bifidobacterium profiles were assessed in stool samples through an innovative test allowing high taxonomic resolution and precise quantification, while SCFAs and branched amino acids were measured in urine samples through gas chromatography–mass spectrometry (GC-MS). KIDMED questionnaires were used to evaluate the children's dietary habits and correlate them with the Bifidobacterium and metabolomic profiles. We found that B. longum subs. infantis and B. breve were higher in individuals with obesity, while B. bifidum and B. longum subs. longum were lower compared to healthy individuals. In individuals with T1D, alterations were found at the metabolic level, with an overall increase in the level of the most measured metabolites. The high taxonomic resolution of the Bifidobacterium test used meant strong correlations between the concentrations of valine and isoleucine, and the relative abundance of some Bifidobacterium species such as B. longum subs. infantis, B. breve, and B. bifidum could be observed. [ABSTRACT FROM AUTHOR]

This article, titled "Editorial: The role of physical and biological gut barriers in modulating crosstalk between the microbiota and the immune system," discusses the importance of the gut barrier in maintaining immune homeostasis and preventing inflammation. The article highlights the role of physical barriers such as the mucus layer, the intestinal epithelial barrier (IEB), and the gut vascular barrier (GVB) in containing microbes and their products within the intestine. It also explores the impact of gut barrier disruption on autoimmune diseases, allergies, and other conditions. The article emphasizes the influence of factors like the gut microbiota, psychological stress, diet, and environmental factors on gut barrier function. Additionally, it suggests that restoring gut barrier integrity could be a potential therapeutic approach for immune-mediated diseases. [Extracted from the article]

Successful transplantation requires the prevention of allograft rejection and, in the case of transplantation to treat autoimmune disease, the suppression of autoimmune responses. The standard immunosuppressive treatment regimen given to patients with autoimmune type 1 diabetes who have received an islet transplant results in the loss of T cells. In many other situations, the immune system responds to T cell loss through cytokine-dependant homeostatic proliferation of any remaining T cells. Here we show that T cell loss after islet transplantation in patients with autoimmune type 1 diabetes was associated with both increased serum concentrations of IL-7 and IL-15 and in vivo proliferation of memory [CD45RO.sup.+] T cells, highly enriched in autoreactive glutamic acid decarboxylase 65-specific T cell clones. Immunosuppression with FK506 and rapamycin after transplantation resulted in a chronic homeostatic expansion of T cells, which acquired effector function after immunosuppression was removed. In contrast, the cytostatic drug mycophenolate mofetil efficiently blocked homeostatic T cell expansion. We propose that the increased production of cytokines that induce homeostatic expansion could contribute to recurrent autoimmunity in transplanted patients with autoimmune disease and that therapy that prevents the expansion of autoreactive T cells will improve the outcome of islet transplantation., Introduction Lymphocyte loss is a hallmark of T cell depletion therapy and certain infections. The immune system can sense T cell loss and responds with a vigorous cytokine-dependent expansion of [...]

The gut microbiota modulates the autoimmune pathogenesis of type 1 diabetes (T1D) via mechanisms that remain largely unknown. The inflammasome components are innate immune sensors that are highly influenced by the gut environment and play pivotal roles in maintaining intestinal immune homeostasis. In this study we show that modifications of the gut microbiota induced by oral treatment with Lactobacillaceae-enriched probiotic VSL#3, alone or in combination with retinoic acid (RA), protect NOD mice from T1D by affecting inflammasome at the intestinal level. In particular, we show that VSL#3 treatment inhibits IL-1β expression while enhancing release of protolerogenic components of the inflammasome, such as indoleamine 2,3-dioxygenase (IDO) and IL-33. Those modifications of the intestinal microenvironment in VSL#3-treated NOD mice modulate gut immunity by promoting differentiation of tolerogenic CD103+ DCs and reducing differentiation/expansion of Th1 and Th17 cells in the intestinal mucosa and at the sites of autoimmunity, that is, within the pancreatic lymph nodes (PLN) of VSL#3-treated NOD mice. Our data provide a link between dietary factors, microbiota composition, intestinal inflammation, and immune homeostasis in autoimmune diabetes and could pave the way for new therapeutic approaches aimed at changing the intestinal microenvironment with probiotics to counterregulate autoimmunity and prevent T1D. [ABSTRACT FROM AUTHOR]