The correlation between adiposity and adiponectin, tumor necrosis factor alpha, interleukin-6 and high sensitivity C-reactive protein levels. Is adipocyte size associated with inflammation in adults?

Abstract

Objective: Hypertrophic obesity correlates with metabolic complications of obesity. We evaluated adipocyte volume and its relationship with tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), adiponectin and high sensitivity C-reactive protein (hs-CRP) levels.

Subjects and methods: Patients were divided into 4 groups; lean healthy controls [body mass index (BMI): 24.2+/-1.4 kg/m2], non-diabetic obese patients (30.2+/-2.9), obese (30.1+/-3.2) and non-obese (22.2+/-1.5) Type 2 diabetic patients. TNF-alpha, hs-CRP, adiponectin and IL-6 levels were measured preoperatively and sc fat specimens were obtained during operation. Semi-thin sections were stained with toluidine-blue and evaluated by light microscopy. Fat volumes were calculated by Goldrick's formulation.

Results: Mean adipocyte volumes were higher in obese diabetic patients than in other groups (p<0.0001). Mean TNF-alpha, hs-CRP and IL-6 levels were higher in obese diabetic patients than in control subjects, obese non-diabetic and non-obese diabetic patients (p<0.0001, p<0.02 and p<0.01, respectively). Mean TNF-alpha levels of non-diabetic obese patients were higher than the control group (p<0.05). Mean IL-6 levels of diabetic and non-diabetic obese patients were higher than control subjects (p<0.02 and p<0.0001, respectively). Mean adiponectin levels of control subjects were higher than non-diabetic obese, non-obese diabetic and obese-diabetic subjects (p<0.0001). Mean adiponectin levels of obese diabetic patients were lower than non-diabetic obese subjects (p<0.008). Mean hs-CRP levels were higher in diabetic patients whether they were obese or not. There was a positive correlation between adipocyte size and TNF-alpha (p<0.01), IL-6 (p<0.03) and hs-CRP levels (p<0.004), and negative correlation between adipocyte size, adiponectin levels (p<0.0001).

Conclusions: TNF-alpha, IL-6 and hs-CRP levels were positively, adiponectin negatively correlated with adipocyte size. Therefore, adiposity may be an inflammatory condition.