Circulating C1q/TNF-related protein isoform 15 is a marker for the presence of metabolic syndrome

Background C1q/TNF-related protein isoform 15 (CTRP15) has been reported to be related to glucose and lipid metabolism, but the results are inconsistent. Metabolic syndrome (MetS) is a cluster of metabolic disorders. The aim of this study is to determine circulating CTRP15 levels in individuals with MetS and investigate the association among circulating CTRP15 and markers for MetS as well as insulin resistance. Methods A total of 341 individuals were recruited for this cross-sectional study. These subjects were screened for MetS. Serum CTRP15 concentrations were measured by ELISA. Results Serum CTRP15 levels were significantly higher in MetS individuals relative to those of the healthy individuals. Circulating CTRP15 correlated positively with WHR, BMI, SBP, FAT %, 2 h-BG, FIns, 2 h-Ins, TG, FFA, HbA1c, HOMA-IR, and AUC(glucose), while negatively with HDL-C and ISI. Multiple linear regression showed that HOMA-IR and HDL-C are independently related factors influencing serum CTRP15 concentrations. In addition, binary logistic regression analysis showed that serum CTRP15 concentrations were significantly related to MetS. When the mean concentrations of circulating CTRP15 in MetS subjects were stratified by the number of components of the MetS, circulating CTRP15 was found to increase progressively with increasing number of the MetS components. Finally, ROC curve analysis showed that the best cutoff values for circulating CTRP15 to predict MetS and insulin resistance were 63.6 and 64.0 mu g/L. Conclusions Serum CTRP15 concentrations were associated with the key components of MetS and insulin resistance.