Truncal fat mass as a contributor to inflammation in end-stage renal disease

Background: An activated inflammatory response is a common feature of end-stage renal disease (ESRD) and predicts outcome. Adipose tissue is an endocrine organ that may contribute to an inflammatory burden by secreting adipocytokines such as interleukin 6 (IL-6). Objective: The objective was to relate plasma concentrations of IL-6 in ESRD patients to body composition, regional fat mass distribution, and blood lipid profiles. Design: One hundred ninety-seven ESRD patients (123 men; (x) over bar +/- SE age: 52 +/- 1 y) were evaluated shortly before dialysis started. Lean body mass and truncal and nontruncal fat mass were estimated by dual-energy X-ray absorptiometry. Nutritional status was evaluated on the basis of subjective global assessment and handgrip strength. Inflammatory biomarker and blood lipid concentrations were also evaluated. Results: Median IL-6 (8.5 compared with 4.5 pg/mL; P < 0.001) concentrations were significantly greater in malnourished than in well-nourished patients. Moreover, negative correlations were observed between IL-6 and serum creatinine (rho = -0.19, P < 0.01), handgrip strength (rho = -0.24, P < 0.001), and serum albumin (rho = -0.34, P < 0.001). A significantly higher truncal fat mass (12.8 +/- 0.7 compared with 10.5 +/- 0.4 kg; P < 0.005) was observed in ESRD patients with inflammation (C-reactive protein greater than or equal to 10 mg/L). Inverse correlations were observed between plasma IL-6 and HDL cholesterol (rho = -0.16, P < 0.05) and apolipoprotein A (rho = -0.23, P < 0.001). Conclusions: Plausible relations exist between inflammatory biomarkers, such as IL-6 and high-sensitivity C-reactive protein, and regional fat distribution in ESRD patients. Moreover, the strong inverse relations between HDL cholesterol and apolipoprotein A and biomarkers of inflammation suggest that the chronic inflammatory response observed in ESRD patients is an important contributor to the atherogenic lipoprotein profile in uremia.