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Repaglinide is a short-acting insulin secretagogue, which often results in considerable interindividual variability in therapeutic efficacy when widely used in a clinical setting. Among various reasons under discussion is genetic polymorphism, especially the genes related to insulin secretion and resistance. Recent studies have described the importance of PPARD in regulating the secretion and resistance of insulin. However, little is known about the impacts of PPARD genetic polymorphism on the efficacy of repaglinide. Therefore, the current study was designed to investigate the associations of PPARD rs2016520 polymorphism with type 2 diabetes mellitus (T2DM) susceptibility and repaglinide therapeutic efficacy in Chinese Han T2DM patients. A total of 338 T2DM patients and 200 healthy subjects were genotyped for PPARD rs2016520 polymorphism by polymerase chain reaction-restriction fragment length polymorphism assay. A total of 84 patients with the same genotypes of CYP2C8*3 139Arg and OATP1B1 521TT were randomized to orally take repaglinide for 8 weeks. Then the pharmacodynamic parameters of repaglinide and biochemical indicators were determined before and after repaglinide treatment. No significant difference was found in either allelic frequency (P = 0.298) or genotype distribution (P = 0.151) of PPARD rs2016520 between T2DM patients and healthy subjects. However, T2DM patients carrying genotype TC showed a significantly lower increase in postprandial serum insulin (mU/L) than those with wild-type TT (P < 0.05). These findings suggest that PPARD rs2016520 polymorphism might influence the therapeutic effect of repaglinide rather than T2DM susceptibility in Chinese Han T2DM patients., (© 2014 Wiley Publishing Asia Pty Ltd.)

Study Objective: To investigate the associations of NOS1AP rs12742393 polymorphism with the risk of type 2 diabetes mellitus (T2DM) and repaglinide therapeutic efficacy in Chinese patients with T2DM., Design: Prospective case-control study., Setting: Academic medical center., Patients: A total of 300 patients with T2DM and 200 healthy volunteers were enrolled to identify NOS1AP rs12742393 genotypes using the polymerase chain reaction-restriction fragment length polymorphism assay. Eighty-four patients with various genotypes were randomly selected to receive oral repaglinide as a single-agent therapy (3 mg/day) for 8 weeks., Measurements and Main Results: Anthropometric measurements and fasting plasma glucose (FPG), postprandial plasma glucose, hemoglobin A1c , fasting serum insulin (FINS), postprandial serum insulin, homeostasis model assessment for insulin resistance (HOMA-IR), triglyceride, total cholesterol, low-density lipoprotein-cholesterol, and high-density lipoprotein-cholesterol tests were obtained before and after repaglinide treatment. The risk C allelic frequency of NOS1AP rs12742393 was higher in patients with T2DM than in healthy volunteers (p<0.001). Patients with T2DM and genotypes AA and AC at NOS1AP rs12742393 had a significant reduction in FPG (mmol/l) compared with those with genotype CC (p<0.01). Patients with CC homozygotes and AC heterozygotes had a greater increase in FINS (mU/l) than those with wild-type AA (p<0.05). In addition, the carriers of genotype CC at NOS1AP rs12742393 had higher differential values of HOMA-IR compared with genotypes AC and AA carriers (p<0.001). The effects of repaglinide treatment on FPG (p<0.01), FINS (p<0.05) and HOMA-IR (p<0.001) were reduced in patients with T2DM carrying the NOS1AP rs12742393 risk C allele compared with the AA genotype carriers., Conclusion: The NOS1AP rs12742393 polymorphism is associated with therapeutic efficacy of repaglinide in Chinese T2DM patients., (© 2013 Pharmacotherapy Publications, Inc.)