Metabolic diseases such as diabetes and obesity are becoming a major concern for all countries. In developing countries such as South Asia, which are affected by the highest rate of population growth, the social system cannot afford the corresponding expenses. One of the major consequences linked to the occurrence of these metabolic diseases is the rapid increase in cardiovascular events leading to death (1). Therefore, in Western countries, where metabolic diseases are firmly established, as well as in Eastern countries, where diabetes and obesity are strongly emerging, there is a crucial need to identify the risk factors of diabetes and obesity and to find new therapeutic targets.
What is Type I Diabetes?
In Type I Diabetes, the body’s immune system attacks part of its own pancreas. In fact, the immune system ,more specifically T cells — which are a type of immune cells that destroys foreign particles, recognizes the insulin-producing cells in the pancreas as foreign and destroys them. This type of attack is known as autoimmunity. The insulin-producing cells, also called “islets”, are the cells that sense glucose in the blood and, in response, produce the necessary amount of insulin to normalize blood sugars. Without insulin, sugar builds up in the blood. If left untreated, the high level of blood sugar can damage the eyes, kidneys, nerves, and heart (2).
Gut Microbiota and Diabetes
A high incidence of Type I Diabetes has now plagued developed countries for several decades, where environmental conditions have dramatically changed (3).
Recent research has shown the critical role of the gastrointestinal microbiota in both the protection and development of Type I Diabetes. The discovery of the role of intestinal microbiota came from the observation that the incidence of spontaneous Type I Diabetes in a certain type of mouse colony can be affected by the microbial environment in the animal housing facility or by exposure to microbial stimuli such as injection with mycobacterium (a type of bacteria) or various microbial products (4).
Studies on rats have shown that bacterial species such as Lactobacillus johnsonii and Lactobacillus reuters prevented the development of Type I Diabetes. Moreover, observations following the administration of antibiotics in Type I Diabetic rat models showed that the occurrence of the disease was reduced, strengthening the hypothesis that a specific intestinal microbiota composition can induce autoimmune diseases, including Type I Diabetes.
Thus, prevention of Type I Diabetes can, in the future, be based on interventions targeting the gut microbiota.