Circulating markers of inflammation and their link to indices of adiposity

Adipose tissue produces a number of inflammatory mediators. Circulating concentrations of these inflammatory markers are increasingly used as markers of local or systemic inflammation. This study compares results for 3 inflammatory adipokines measured using 2 techniques, (multiplex and ELISA), and determines the relationships with C-reactive protein (CRP), obesity, and the impact of moderate weight loss.

Fasting blood samples were collected at baseline and after a 24-week weight loss intervention. Interleukin 6 (IL-6), tumour necrosis factor alpha(TNF-alpha), and monocyte chemoattractant protein 1 (MCP-1) were measured using a standard ELISA technique or a new multiplex technique. A total of 54 women with complete data were included in this analysis.

Multiplex showed poor correlation with ELISA results, and were not significantly correlated with CRP. Using ELISA data, IL-6 and CRP were significantly correlated with body mass index (BMI) (r = 0.42 and r = 0.55), but MCP-1 and TNF-alpha were not (r = - 0.07 and r = 0.06). Changes in MCP-1, TNF-alpha, and IL-6 were not significantly different between control and weight loss groups. CRP was significantly reduced in weight loss vs. control group (p < 0.05), and change in CRP correlated with change in BMI (r = 0.31).

Circulating IL-6 and CRP, but not MCP-1 and TNF-alpha, are significantly associated with indices of adiposity in obese women. This study suggests that circulating IL-6 and CRP, but not MCP-1 and TNF-alpha, are useful markers of obesity-related inflammation.