Fasting plasma glucose (FPG, mmol/L), total cholesterol (TC, mmol/L), high-density lipoprotein cholesterol (HDL, mmol/L), and triglyceride (TG, mmol/L) levels were determined for all subjects, using standard laboratory methods and commercially available test kits (Roche Diagnostics GmbH, Mannheim, Germany). Low-density lipoprotein (LDL, mmol/L) cholesterol values were obtained using the Friedewald formula. Insulin levels (μU/mL) were measured using an enzyme-linked immunoassay kit (DRG Instruments GmbH, Marburg, Germany), with a lower limit of sensitivity of 1.76 μU/mL, and intra- and interassay coefficients of variation of 2.2% and 4.4%, respectively.
The index of IR, HOMA-IR, was calculated according to the homeostasis model formula as follows23 (link): HOMA-IR = insulin × FPG / 22.5, where insulin is the fasting insulin level (μU/mL), and FPG is the fasting plasma glucose level (mmol/L).
Chemerin was measured in serum using a sandwich enzyme-linked immunosorbent assay (ELISA) (Human Chemerin DuoSet ELISA Kit, catalog No. DY2324, R&D Systems, Inc, Minneapolis, MN, USA) following the manufacturer’s instructions. The respective intra- and interassay coefficients of variation were 4.5% and 4%. The sensitivity of the ELISA assay was 0.0625 to 2 ng/mL.
The index of IR, HOMA-IR, was calculated according to the homeostasis model formula as follows23 (link): HOMA-IR = insulin × FPG / 22.5, where insulin is the fasting insulin level (μU/mL), and FPG is the fasting plasma glucose level (mmol/L).
Chemerin was measured in serum using a sandwich enzyme-linked immunosorbent assay (ELISA) (Human Chemerin DuoSet ELISA Kit, catalog No. DY2324, R&D Systems, Inc, Minneapolis, MN, USA) following the manufacturer’s instructions. The respective intra- and interassay coefficients of variation were 4.5% and 4%. The sensitivity of the ELISA assay was 0.0625 to 2 ng/mL.