MacRophage-Adipocyte Cross-Talk : ROLE OF ADIPONECTIN IN THE INITIATION OF OBESITY-RELATED INSULIN RESISTANCE AND TYPE 2 DIABETES

Recent studies suggest that chronic inflammation of adipose tissues with macrophage infiltration and enhanced expression of pro-inflammatory cytokines plays a significant role in the development of obesity-related metablic disorders, such as type 2 diabetes. It was demonstrated that adenovirus- mediated over-expression of adiponectin, an anti- inflammatory insulin-sensitizing adipokine with reduced expression in obesity, resulted in a marked down-regulation of several inflammation-related genes, including F4/80 and CD68 (macrophage markers), and monocyte chemotactic protein-1 (MCP- 1), in the white AT of 12 weeks old db/db diabetic mice. It was hypothesized that the reduced expression of adiponectin might play an important role in initiating macrophage-adipocyte cross-talk which leads to obesity-related insulin resistance and diabetes. This study aimed at determining the time course and magnitude of macrophage infiltration and inflammatory activation in AT, in relation to changes in the AT level of adiponectin, glucose tolerance and insulin sensitivity, in db/db diabetic mice.