Elevated adipose tissue expression of CCL19 in obese individuals with or without type-2 diabetes: Its association with metabolic inflammation

Abstract

Abstract Adipose tissue produces inflammatory molecules considered to be involved in the development of chronic low-grade inflammation in obesity and type 2 diabetes (T2D). The adipose tissue expression of CCL19 or macrophage inflammatory protein (MIP)-3β in obesity is poorly understood. We, therefore, determined CCL19 gene expression in the adipose tissue samples from lean, overweight, and obese individuals with or without T2D. Subcutaneous adipose samples were collected from 58 non-diabetic (ND) (27-obese, 21-overweight, and 10-lean) and 49 T2D (34-obese, 11-overweight, and 4-lean) individuals. Gene expression of CCL19 and other inflammatory markers was determined using real-time RT-PCR. Plasma CRP and adiponectin were measured by ELISA. CCL19 expression was significantly higher in obese compared with lean individuals (ND: P<0.04; T2D: P<0.02). Notably, CCL19 expression was relatively higher in T2D than ND individuals regarding each body mass index (BMI) group. CCL19 expression correlated with BMI (ND: r=026, p=0.04; T2D: r=0.45, P=0.001). In relation to immune markers, CCL19 expression had association with CXCL10, IL-12A, and TLR2 in ND individuals, and with IL-6, IL-1β, TGF-β, TNF-α, TLR9, CCL11 and IRAK-1 in T2D individuals, while it associated with MyD88, CCL5, CCR2, and CRP in both populations. However, CCL19 gene expression associated negatively with adiponectin in ND individuals. With regard to clinical markers, in both populations, CCL19 expression correlated positively with triglycerides, fasting blood glucose, and HbA1C, whereas it had negative association with HDL cholesterol. These data support that increased adipose tissue expression of CCL19 may represent an immune signature of metabolic inflammation.