Objective: To investigate the effect of single nucleotide polymorphism (SNP) + 45 of the adiponectin (ADIPOQ) gene on the response to therapy with rosiglitazone maleate in patients with type 2 diabetes.
Methods: A total of 103 newly diagnosed type 2 diabetes patients without taking any drug were enrolled and treated with rosiglitazone maleate (4 or 8 mg/d) for 24 weeks. On scheduled time phenotype measured were height, weight, waist, hip; blood pressure; HbA1c; plasma glucose level, serum insulin level, serum proinsulin level of blood obtained at 0, 2, 4 and 6 minute during arginine stimulation test; serum lipid level including total cholesterol, triglyceride, high-density and low-density lipoprotein cholesterol. Response to the rosiglitazone maleate therapy was defined by both a > or = 20% decrease in fasting plasma glucose and a > or = 15% decrease in HbA1c values after 24 weeks of rosiglitazone maleate treatment. All patients were genotyped for the ADIPOQ SNP + 45 by PCR-RFLP.
Results: (1) Of the 103 patients, the frequencies of TT, TG and GG genotypes of ADIPOQ SNP + 45 were 0.55, 0.36 and 0.09 respectively. The T allele frequency and G allele frequency were 0.73 and 0.27 respectively. (2) There was a significant difference in the response rate to rosiglitazone maleate treatment between the TT genotype and the TG + GG genotype (P = 0.0295). Response rate of the TG + GG genotype (56.41%) was higher than that of the TT genotype (33.93%). Furthermore, multivariate Logistic regression analysis revealed that SNP + 45 of ADIPOQ gene and HbA1c were the independent risk factors for rosiglitazone maleate treatment response. (3) After 24 weeks of treatment period, the FPG, 2hPG, HbA1c and HOMA-IR were significantly decreased in comparison with pre-treatment in both genotype groups. (4) The change in the clinical parameters after 24 weeks of treatment period showed no significant difference between the SNP + 45 of ADIPOQ gene.
Conclusion: SNP + 45 of ADIPOQ gene is associated with the response rate to rosiglitazone maleate treatment in patients with type 2 diabetes and may be the major determinant of response rate. The response rate of the TG + GG genotype is higher than that of the TT genotype.