IL-32 has inflammatory properties in human obesity

(HealthDay)—Interleukin (IL)-32 has inflammatory and remodeling properties in human obesity, according to a study published online Sept. 14 in Diabetes.

Victoria Catalán, Ph.D., from the Clínica Universidad de Navarra in Pamplona, Spain, and colleagues examined whether IL-32 could function as an inflammatory and angiogenic factor in human obesity and obesity-associated type 2 diabetes. Samples were obtained from 90 subjects.

The researchers found that increased circulating IL-32 levels in obese patients decreased after Roux-en-Y gastric bypass-induced weight loss, but not following a conventional hypocaloric diet. For obese patients, expression levels of IL-32 were higher in visceral adipose tissue as well as in subcutaneous adipose tissue and peripheral mononuclear blood cells. Expression of IL32 was mainly by stromovascular fraction cells, and expression was enhanced by inflammatory stimuli and hypoxia; no changes were seen after incubation with anti-inflammatory cytokines. In human adipocyte cultures, the addition of exogenous IL-32 induced the expression of inflammation and extracellular matrix-related genes; downregulation of inflammatory genes was seen in IL32-silenced adipocytes. Adipocyte-conditioned media from obese patients, but not from lean volunteers, increased IL32 gene expression in human monocyte cultures.

"These findings provide evidence, for the first time, about the inflammatory and remodeling properties of IL-32 in adipose tissue implicating this cytokine in obesity-associated comorbidities," the authors write.