NEW YORK (Reuters Health) – Certain obese people demonstrate potentially harmful proinflammatory changes in their adipose tissue, researchers report in the September issue of Arteriosclerosis, Thrombosis, and Vascular Biology.

As senior investigator Dr. Noyan Gokce told Reuters Health, “Our data demonstrate that obese subjects exhibit varying degrees of inflammation in their fat tissue, and increased inflammatory activity in fat was associated with systemic metabolic abnormalities including insulin resistance.”

Dr. Gokce of Boston University School of Medicine and colleagues studied subcutaneous abdominal fat samples from 77 obese subjects. The researchers found that 50 of the subjects had an inflamed adipose phenotype characterized by tissue macrophage accumulation in crown-like structures.

Compared to subjects with a quiescent non-inflamed phenotype, these findings were associated with systemic hyperinsulinemia and insulin resistance, as well as an impaired endothelium-dependent flow-mediated vasodilation.

In addition, macrophage retention in fat was associated with upregulated tissue CD68 and tumor necrosis factor mRNA expression and with increased plasma high sensitivity C-reactive protein.

Because adipose inflammation was linked to impaired arterial endothelial function, Dr. Gokce pointed out, “that may identify obese individuals at increased cardiovascular risk.”

Arterioscler Thromb Vasc Biol 2008;28:1654-1659.