Could Microbes Protect Against Type 1 Diabetes?
The human body is a haven for countless numbers of microbes, including bacteria, that can be detrimental, causing a wide range of diseases, or act as protection against illness. An international team of researchers recently reported that a certain category of microbes have been shown to protect against type 1 diabetes.
The team consisted of experts from Inserm, Paris Descartes University, and the French National Centre for Scientific Research, who collaborated with teams from Sweden and China. Their focus was on cathelicidins, a type of antimicrobial peptides (two or more amino acids linked together), which are known to destroy disease-causing bacteria.
Cathelicidins also have demonstrated immunoregulatory abilities in a number of autoimmune diseases, which prompted the researchers to investigate whether these peptides could be helpful in controlling type 1 diabetes. In this autoimmune disease, the immune system attacks and destroys the beta cells, which produce insulin, leaving individuals dependent on an outside source of insulin for the rest of their lives.
Once the researchers noted that nondiabetic mice produce cathelicidins while diabetic mice do not, they injected the diseased mice with the peptides. According to one of the study’s authors, Julien Diana, “Injecting cathelicidins inhibits the development of pancreatic inflammation and, as such, suppresses the development of autoimmune disease in these mice.”
The team also observed that diabetic mice have less short-chain fatty acids than do healthy mice. Because cathelicidin production is regulated by short-chain fatty acids, which are produced by gut bacteria, the team is now investigating whether these bacteria may be behind the deficiency of cathelicidin in the diseased mice.
In fact, the investigators transferred gut bacteria from healthy mice to those with diabetes to encourage normal cathelicidin levels. This step resulted in a reduction in the occurrence of diabetes in the mice.
Other research to protect against type 1 diabetes
Much research has been conducted on ways to stop or prevent type 1 diabetes. For example:
- A study from Scripps Research Institute in Florida and St. Louis University School of Medicine found that blocking two receptors in mouse models resulted in stopping the destruction of insulin-producing beta cells
- At the University of Copenhagen, experts discovered that very low doses of cancer drugs called lysine deacetylase inhibitors resulted in a 38 to 45 percent reduction in the development of type 1 diabetes in mice
- A University of Alabama animal study found that use of the blood pressure drug verapamil can stop the production of a protein that causes the destruction of beta cells in the pancreas
Will this discovery concerning cathelicidin levels apply to humans and type 1 diabetes? Future studies will hopefully answer this question. For now, the authors concluded that their research “is further evidence of the undeniable role microbiota plays in autoimmune diseases, particularly in controlling the development of autoimmune diabetes.”
Also Read: Type 2 diabetes linked to gut bacteria
Sun J et al. Pancreatic beta-cells limit autoimmune diabetes via an immunoregulatory antimicrobial peptide expressed under the influence of the gut microbiota. Immunity 2015 August 4