Abstract
AbstractBackgroundAdiponectin and apolipoprotein M (apoM) are adipokines indicatives of healthy adipose tissue and down-regulated with obesity. We compared circulating apoM with adiponectin regarding their relationship with metabolic parameters and insulin sensitivity and examined their gene expression patterns in adipocytes and in the adipose tissue.MethodsCirculating apoM and adiponectin were examined in 169 men with overweight in a cross-sectional study, and 13 patients with obesity during a surgery-induced slimming program. Correlations with clinical parameters including the insulin resistance index (HOMA-IR) were analyzed. Multiple regression analyses were performed on HOMA-IR. TheAPOMandADIPOQgene expression were measured in the adipose tissue from 267 individuals with obesity and a human adipocyte cell line.ResultsParticipants with type 2 diabetes had lower circulating adiponectin and apoM, while apoM was higher in individuals with dyslipidemia. Similar to adiponectin, apoM showed negative associations with HOMA-IR and hs-CRP (r>-0.2), and positive correlations with HDL markers (HDL-C and apoA-I, r>0.3). Unlike adiponectin, apoM was positively associated with LDL markers (LDL-C and apoB100, r< 0.20) and negatively correlated with insulin and age (r>-0.2). The apoM was the sole negative determinant of HOMA-IR in multiple regression models, while adiponectin not contributing significantly. After surgery, the change in HOMA-IR was negatively associated with the change in circulating apoM (r=-0.71), but not with the change in adiponectin. TheAPOMandADIPOQgene expression positively correlated in adipose tissue (r>0.44) as well as in adipocytes (r>0.81). In adipocytes,APOMwas downregulated by inflammatory factors and upregulated by adiponectin.ConclusionsThe apoM rises as a new partner of adiponectin regarding insulin sensitivity. At the adipose tissue level, the adiponectin may be supported by apoM to promote a healthy adipose tissue.
Publisher
Cold Spring Harbor Laboratory