The small intestine is involved in chronic inflammation in obese people

INSERM: Obesity is caused by many complex factors, some of which are yet unknown. Researchers from the French National Centre for Scientific Research (CNRS), Inserm, Pierre and Marie Curie University (UPMC) and Paris Descartes University, in collaboration with clinician researchers from the Paris Public Hospitals (AP-HP), have just shown that severe obesity is accompanied by inflammation of the small intestine and a strengthening of the immune defences in that area. This phenomenon reduces enterocyte[1] sensitivity to insulin and increases nutrient absorption, thus exacerbating the disease.


Study of the mechanisms involved in human obesity is particularly interesting in the jejunum, a portion of the small intestine that plays a major role in the absorption of lipids and carbohydrates. Because of its location in the body, the jejunum is difficult to study, and its contribution to this metabolic disease was not well known. In this study, the researchers were able to obtain jejunum samples from patients during a surgical operation performed to reduce their obesity and associated diseases (gastric bypass). Samples from 185 individuals suffering from severe obesity were compared with jejunum samples from 33 non-obese individuals, who were operated on for other reasons.

The research teams, coordinated by Edith Brot-Laroche and Karine Clément, observed a state of chronic inflammation in the small intestine in these obese individuals, and colonisation of the jejunal epithelium by T lymphocytes, at a density that increased with degree of obesity. These immune system cells produce cytokines[2] that inhibit the insulin sensitivity of the absorbent cells of the intestinal epithelium. Since the action of insulin regulates nutrient absorption and blood sugar level, this immune system phenomenon thus contributes to the exacerbation of the patient’s clinical situation.