Australian scientists have established for the first time that the cause of obesity and insulin resistance is a malfunction of the lymphatic system of the mesentery, with which the abdominal cavities are connected in the back wall of the abdomen.

And Nature Metabolism reports that scientists from Monasha University’s Melbourne Institute of Pharmaceutical Sciences, along with colleagues from other Australian universities, have discovered that a high-fat diet stimulates the development of a tortuous network of lymphatic vessels in the mesentery. These vessels allow the infiltration of lymph fluid rich in intestinal fat metabolites and inflammatory mediators into the visceral adipose tissue in the abdominal cavity, causing the accumulation of abdominal fat and leading to insulin resistance.

“For the first time in this study, we were able to discover the biological cause of fat accumulation around the abdomen, with higher rates of metabolic diseases, such as type 2 diabetes, compared to fat accumulation in other areas of the body,” says lead researcher Natalie Trevaskis. A high-fat diet leads to mesenteric lymphatic vessel dysfunction, which in turn promotes abdominal fat accumulation and insulin resistance.

In addition, the researchers present empirical evidence that interfering with this cycle by inhibiting pathways associated with lymphatic dysfunction may be a treatment for obesity and related diseases. It turned out that when lab mice were injected with a COX-2 inhibitor, the structure of their mesenteric vessels improved, their weight stopped increasing, and glucose intolerance and elevated blood insulin levels, conditions associated with type 2 diabetes, were eliminated.

The researchers have achieved this success, thanks to an innovative method of delivering the inhibitor directly to the mesenteric lymphatic vessels with a special drug, which the researchers hope, after clinical trials, will become an effective drug in the treatment of obesity and related diseases.