Adipose tissue pro-inflammatory gene expression is associated with cardiovascular disease

Obese patients are at high risk of developing cardiovascular disease. Several studies suggest obesity as an independent risk factor. Adipose tissue is now accepted as an endocrine organ that produces and secretes a variety of cytokines, hormones and other metabolic players involved in the pathogenesis of atherosclerosis. Among this versatile group of mediators and effectors of inflammation and atherothrombosis, we have studied the expression of matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP-1), plasminogen activator inhibitor-1 (PAI-1), interleukin-18 (IL-18) and interleukin-6 (IL-6). All these markers, in their circulatory form, have been associated with cardiovascular disease. However, there is no much data available on their expression in adipose tissue in human subjects with and without cardiovascular disease.

We successfully isolated RNA from subcutaneous fat biopsies of 61 patients with or without cardiovascular disease. We then measured the RNA expression of MMP-9, TIMP-1, PAI-1, IL-18 and IL-6 with Real-Time PCR, using relative quantification.

Albeit not statistically significant, all inflammatory mediators - except IL-18 - were highly expressed in patients with cardiovascular disease (n = 16) compared with those without (n = 45). Pooling the gene expression data, trying to capture the overall inflammatory activity in adipose tissue in a score system, we observed a highly significant association with CVD.

Trying to capture the overall inflammatory activity, in addition to the mass of adipose tissue, could provide useful hints towards a pathogenetic link between obesity and presence of cardiovascular disease.