Study On The Association Of OCT1,MATE1 And ATM Polymorphisms With IR In Patients With Type 2 Diabetes On Metformin Treatment

Backround:Insulin resistance(IR)is a status of decreased response of muscle and adipose tissues to the effects of insulin.IR is not only the basis of the onset of type 2 diabetes mellitus,but also the common pathological basis of obesity,hypertension,hyperlipidemia and atherosclerosis.Therefore,improving IR is of great significance for the treatment of type 2 diabetes mellitus and cardiovascular diseases.Metformin,which increases the binding of insulin to receptors,enhance the sensitivity of peripheral tissues to insulin,improve IR,thereby reducing the risk of cardiovascular complications in patients with diabetes,is currently recommended as a first-line treatment for type 2 diabetes mellitus by multinational guidelines.Organic cation transporter 1(OCT1)and multidrug and toxin extrusion 1(MATE1)are encoded by the OCT1 and MATE1 genes,respectively,and are responsible for the absorption,uptake and excretion of metformin.OCT1 and MATE1 genes mutations lead to changes in the transporter functions of OCT1 and MATE1,thus affecting the blood concentration of metformin in vivo and leading to differences in metformin efficacy.Ataxia telangiectasia mutated gene(ATM)is one of the members of the phosphatidylinositol 3 kinase family,which can affect the glycemic response of metformin by regulating the activation of adenosine monophosphate-activated protein kinase(AMPK).The effect of OCT1,MATE1 and ATM gene polymorphisms on the efficacy of metformin may lead to differences in IR in patients with type 2 diabetes mellitus treated with metformin.At present,there are limited studies on the association between OCT1,MATE1 and ATM gene polymorphisms and IR in patients with type 2 diabetes mellitus treated with metformin,and further research is needed-Objectives:The purpose of this study was to understand the situation of IR after metformin treatment in patients with type 2 diabetes mellitus in china,and to explore the association between OCT1 rs622342,MATEI rs2252281,MATE1 rs2289669 and ATM rs1 1212617 gene polymorphisms and IR in patients with type 2 diabetes mellitus treated with metformin.In order to find genetic predictors of improved IR and provide data reference for clinical individualized treatment of metformin.Methods:Inpatients diagnosed with type 2 diabetes mellitus at the Department of Endocrinology in the First Affiliated Hospital of Shandong First Medical University from April 2018 to May 2019 and received metformin treatment for at least 6 months were recruited in the study.Basic information(Name,age,gender,weight,height,body mass index(BMI),age of onset,and duration),biochemical indicators(Blood pressure,blood lipids,fasting plasma glucose(FPG),liver and kidney function,glycated hemoglobin(HbA1c),insulin and C-peptide),combined medications and combined diseases of the study subjects were querying through the hospital case system.OCT1 rs622342,MATE1 rs2252281,MATE1 rs2289669 and ATMrs11212617 variants were performed by the dideoxy chain-termination method.Chi-square test was used to validate whether the genotype frequency of these four loci followed Hardy-Weinberg equilibrium.Homeostasis model assessment for IR(HOMA-IR)and HOMA for beta cell function(HOMA-BCF)were used to evaluate IR and β cell function of the patients.Linear regression model and generalized multifactor dimensionality reduction(GMDR)were used to analyze the single gene polymorphism of OCT1 rs622342,MATE1 rs2252281,MATE1 rs2289669 and ATM rs1 1212617 and the correlation between gene-gene interaction and HOMA-IR and HOMA-BCF,respectively.Meanwhile,the interference of potential confounders such as gender,duration,body mass index(BMI),FPG,HbAlc and insulin were adjusted.Results:A total of 111 subjects with type 2 diabetes mellitus were included in this study.Hardy-Weinberg equilibrium test showed that the four loci all follow the Hardy-Weinberg equilibrium among this study subjects(rs622342:χ2=0.088,P-0.767;rs2252281:x2=0.662,P=0.338;rs2289669:χ2=0.003,P=0.954;rs11212617:x2=0.705,P=0.401).Analysis of the association between genetic polymorphisms and IR showed that patients carrying the OCT1 rs622342 AA genotype had significantly higher FPG(P=0.014),HbA1c(P=0.046),and HOMA-IR(P=0.004)than those carrying the AC/CC genotype.There was no significant difference in insulin levels,C-peptide levels,and HOMA-BCF index between patients carrying the rs622342 AA genotype and those carrying the C allele.No significant relationship was observed between the three loci of rs2252281,rs2289669 and rs1 1212617 and FPG,HbA1c,insulin,C-peptide,HOMA-IR,and HOMA-BCF.Further analysis showed that the effect of OCT1 rs622342 mutation on HOMA-IR was gender-related.HOMA-IR in males carrying rs622342 AA genotype was significantly higher than those carrying the AC/CC genotype(P=0.021).There was no significant difference in HOMA-IR between females with rs622342 AA genotype and those with AC/CC genotype.Moreover,the effect of ATM rs11212617 variation on HOMA-BCF was also gender-related.Females with rs 11212617 CC genotype had significantly higher HOMA-BCF than those with AA/AC genotype(P=0.038).However,this significant difference was not observed in males.Gene-gene interaction analysis shows that in the HOMA-IR interaction model,the third-order of rs622342-rs 11212617-rs2252281 and the fourth-order of rs622342-rs 11212617-rs2289669-rs2252281 interaction model are statistically significant(P=0.0010),other interaction models have no statistical significance(P>0.05).The fourth-order interaction model of rs622342-rs11212617-rs2289669-rs2252281 has the maximum balance accuracy(0.7782)and the cross-validation consistency is 10/10,which is the best model.The best gene-gene interaction model of HOMA-BCF is the rs2289669-rs2252281 second-order interaction model.It had a maximum test balance accuracy of 0.6313 and a cross-validation consistency of 10/10.However,this model and other interaction models are not statistically significant(P>0.05).Conclusions:In patients with type 2 diabetes who had been treated with metformin for a long time,those with OCT1 rs622342 C allele had significantly lower IR than other genotypes,but β-cell function was not significantly different among patients with different genotypes.Therefore,rs622342 C allele can be used as a predictor for improved IR in patients with type 2 diabetes treated with metformin.The association between rs622342 polymorphism and HOMA-IR,as well as the association between rs 11212617 polymorphism and HOMA-BCF were both gender-related.The third-order interactions of rs622342-rs11212617-rs2252281 and the fourth-order interactions of rs622342-rs11212617-rs2289669-rs2252281 may have a significant effect on IR in patients with type 2 diabetes on metformin treatment.However,the interaction between these four loci rs622342,rs2252281,rs2289669,and rs 11212617 has no significant effect on β-cell function in patients with type 2 diabetes treated with metformin.