Welcome to the first edition of the MICROBIOME UPDATE, which will be an ongoing series on this blog (as well as in my newsletter, MM News). In each edition, we will briefly highlight recently-published research articles – and occasionally quality articles from the popular media – that highlight important advances in our understanding of the microbiome and its role in health. Many of the editions will focus on a particular topic, so you can quickly get up-to-date on recent developments within that topic area.
So, without further ado, here is the first edition:
EDITION TOPIC: Autoimmunity and Inflammatory Bowel Disease
This study used a mouse model of chemically-induced colitis to evaluate the effects of a probiotic strain (Lactobacillus acidophilus SMC-S095) on a key pathway involved in the pathogenesis of colitis (the IL-23/Th17 pathway). They found that L. acidophilus SMC-S095 was able to suppress key components of the pathway, suggesting that this probiotic strain may prove to be useful for treating at least some inflammatory bowel diseases. Studies in humans are needed in order to verify the effectiveness of this strain.
This article summarizes what’s currently known about the critical role of Th17 cells and the microbiome in Type I diabetes. Th17 cells were only recently recognized, but are now thought to play a critical role in a wide variety of autoimmune and inflammatory disorders, so it’s well worth spending some time getting to know this type of T helper cell. For example, Th17 cells are though to play a role in normal intestinal homeostasis, but when Th17 responses are excessive or insufficient (possibly due to dysbiosis), they may play a role key role in certain diseases.
Berberine ameliorates chronic relapsing dextran sulfate sodium-induced colitis in C57BL/6 mice by suppressing Th17 responses
This study examined the effect of berberine in a mouse model of chronic relapsing ulcerative colitis. Berberine improved several measures of disease severity, and had an especially strong effect in suppressing Th17-related responses, including inflammatory cytokine gene expression, providing support for exploring the use of berberine in ulcerative colitis in humans.
Oral probiotic VSL#3 prevents autoimmune diabetes by modulating microbiota and promoting indoleamine 2,3-dioxygenase-enriched tolerogenic intestinal environment
This study used a mouse genetic model that is prone to developing Type 1 diabetes to show that the probiotic VSL#3 prevented the development of the disease. They went on to show that VSL#3 appeared to work in part by reducing a key inflammatory cytokine (IL-1 beta) and increasing immune tolerance. These VSL#3-induced changes resulted in reduced levels of Th1 and Th17 cells, which have been linked to many autoimmune diseases.
Interaction of intestinal microorganisms with the human host in the framework of autoimmune diseases
This review article discusses the role of the microbiome in systemic lupus erythematosus – an autoimmune disease. The article focuses on what is known about the role of dysbiosis, where specific changes in the composition of the microbiome may contribute to the disease via interaction with specific receptors on cells in the intestinal mucosa. They also discuss the possible role of molecular mimicry, superantigens (a group of toxins produced by many bacteria as well as viruses), and other potential ways they microbiota may contribute to autoimmune disease. Lastly, they discuss some ways in which dietary components and supplements (e.g., fiber, certain polyphenols, and probiotics) may improve autoimmune conditions by increasing Treg cells, which suppress other T helper cells (e.g., Th1, Th17) that are implicated in autoimmune conditions.
This recent blog post from Dr. Jill Carnahan discusses the use of low-dose naltrexone for a range of autoimmune and inflammatory disorders. At the end of the post is a video in which Dr. Carnahan discusses low-dose naltrexone in an interview.