T-lymphocyte infiltration in visceral adipose tissue: a primary event in adipose tissue inflammation and the development of obesity-mediated insulin resistance.

Description

Although the role of macrophage infiltration in adipose tissue in promoting obesity-mediated insulin resistance is well established, the role of other inflammatory cells such as T-lymphocytes has not been examined. In order to investigate the relationship between T-lymphocyte infiltration of intra-abdominal (visceral) adipose tissue and the development of insulin resistance, Kintscher et al. induced insulin resistance in a mouse model of obesity after 5 weeks of high-fat diet feeding, a phenomenon that was associated with T-lymphocyte infiltration in intra-abdominal adipose tissue, but not with macrophage infiltration, the latter having been detected 10 weeks after the beginning of the high-fat diet. The role of T-lymphocyte infiltration of intra-abdominal adipose tissue was also examined in patients with type 2 diabetes who underwent adipose tissue biopsies. The authors showed that the lymphocyte content of adipose tissue correlated positively with waist circumference, a crude marker of intra-abdominal obesity. Macrophages were also detected in the adipose tissue of those patients. These results lend initial weight to the role of T-lymphocytes in promoting insulin resistance associated with an expanded intra-abdominal adipose tissue depot.