| ObjectiveBetatrophin,a newly identified secreted protein,has been recently found to be significantly increased under insulin resistance.This study measured for the first time serum betatrophin levels in newly diagnosed patients with type 2 diabetes mellitus(T2DM)with transient continuous subcutaneous insulin infusion(CSII)therapy and explored the correlations between its levels and insulin resistance,type 2 diabetes mellitus.MethodsA total of 120 subjects were recruited in this study,60 newly diagnosed T2 DM patients(T2DM)and 60 age-,sex-,and BMI-matched normal control subjects(NC).Anthropometric characteristics were measured.Oral glucose tolerance test(OGTT)and insulin releasing test were performed and glucose,glycosylated hemoglobin(HbA1c),insulin and blood lipids were measured in all of the included participants.Insulin resistance was estimated by index of homeostasis modelassessment of insulin resistance(HOMA-IR).?-cell functions were assessed by homeostasis model assessment of insulin secretion(HOMA-?).We analyzed the concentrations of betatrophin by ELISA.The patients should retest the above index after CSII therapy for two weeks in T2 DM group.Results(1)Compared with the NC group,HbA1 c,fasting plasma glucose(Glu0),2 h post-OGTT glucose(Glu120),HOMA-IR,triglyceride(TG),total cholesterol(TC),low density lipoprotein cholesterin(LDL-C)in T2 DM group were significantly increased(P(27)0.05 or P(27)0.01),while fasting insulin(Ins0),high density lipoprotein cholesterin(HDL-C)and HOMA-? were significantly decreased(P(27)0.05 or P(27)0.01).(2)Serum betatrophin levels were significantly higher in T2 DM patients than in normal control subjects(P(27)0.01).(3)In T2 DM group,serum betatrophin levels correlated positively with Glu0,Glu120,HbA1 c and HOMA-IR(P(27)0.05).(4)After treatment,Glu0,30 min post-OGTT glucose(Glu30),1 h post-OGTT glucose(Glu60),Glu120,3 h post-OGTT glucose(Glu180),TG,TC,HDL-C,LDL-C and HOMA-IR were lower than the levels before in T2 DM patients(P(27)0.05 or P(27)0.01),while 30 min post-OGTT insulin(Ins30),1 h post-OGTT insulin(Ins60),2 h post-OGTT insulin(Ins120),3 h post-OGTT insulin(Ins180),30 min post-OGTT C-peptide(C-P30),1 h post-OGTT C-peptide(C-P60),2 h post-OGTT C-peptide(C-P120),3 h post-OGTT C-peptide(C-P180)and HOMA-? were higher than prior treatment.(5)After 2 weeks' intensive treatment,the levels of betatrophin in T2 DM patients were respectively significantly higher than the levels before treatment,[448.83(229.89-719.68)vs.393.79(168.51-577.63)pg/m,P(27)0.05].(6)In T2 DM group,the levels of serum betatrophin before treatment negatively correlated with the change of fasting glucose(?Glu0),1 h post-OGTT glucose(?Glu60)and HOMA-IR(?HOMA-IR),while positively correlated with the change of 30 min post-OGTT insulin(?Ins30),1 h post-OGTT insulin(?Ins60),2 h post-OGTT insulin(?Ins120),C-P30(?C-P30),C-P60(?C-P60),C-P120(?C-P120)and C-P180(?C-P180)(P(27)0.05).In the patients of T2 DM,the change of betatrophin before and after therapy positively correlated with the change of C-P0(?C-P0)and Ins0(?Ins0)(P(27)0.05).(7)In T2 DM group,multivariate regression models were fit for the change of betatrophin before and after treatment as a dependent variable,including all variables of interest at the same time as independent variables to demonstrate the relative contribution to the outcome ones.The results showed that ?C-P0(?=172.03,P=0.016)was independently related factor influencing serum ?Betatrophin(R2=0.103,P(27)0.05).Conclusions(1)Our results indicate that circulating betatrophin concentrations were significantly increased in patients with newly diagnosed T2 DM and associated with glucose,lipid homeostasis,insulin resistance.(2)The concentration of serum betatrophin was elevated after two weeks of CSII in newly diagnosed T2 DM.The ?Betatrophin positively correlated with ?C-P0 and ?Ins0.The ?C-P0 was the independently related factor influencing the ?Betatrophin levels(R2=0.103,P(27)0.05).(3)Betatrophin may play an important role in the pathogenesis of T2 DM. |
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