Study Of The Role Of RBP4 And FFA In The Pathogenesis Of GDM

Objectives:To investigate the change level of serum retinol binding protein 4 and free fatty acid and to analyze the relationship of retinol binding protein 4 and free fatty acid to metabolic and clinical biochemical indicators in the subjects of normal gestational test,GIGT and GDM,in order to explore the role of RBP4 which was discovered as another adipokine recently and FFA in the pathogenesis of insulin resistance and GDM in gestational women.MethodsBased on the results of GDM screening and 75g oral glucose tolerance at weeks 24-28,80 subjects were stratified into three groups according to different blood glucose in different times:normal glucose tolerance(NGT),gestational impaired glucose tolerance(GIGT) and gestational diabetes mellitus GDM).And groupde the pregnant women into normal weight cases and obesity cases.Anthropometric measurements included:height,weight,body mass index(BMI=kg/m~2).Blood sample for measurements of total cholesterol(TC),triglyceride(TG),fasting blood glucose(FBG),fasting insulin(FINS).The concentrarion of serum retinol binding protein 4(RBP4)was measured by ELISA method and free fatty acid(FFA) was measred by colorimetric method.The homeostasis model(HOMA) was adopted to estimated the index of insulin resistance:HOMA-IR=FBG×FINS /22.5.These clinical indicators were analyzed by SPSS 11.5 software for windows.Results(1)The level of serum retinol binding protein 4 was gradually increased from NGT group,GIGTgroup to GDM group,and the difference between theses groups was significant(P＜0.001);Meanwhile serum retinol binding protein 4 in obsety group was significantly higher than normal weight group and the difference was significance.(2)Serum free fatty acid(FFA)in NGT group was lowest and GDM group was highest and the differences among these groups were significant(P＜0.05).(3)The concentration of fasting insulin in NGT group was gradually increased from NGT group,GIGT group to GDM group[NGT:13.76±3.427 GIGT:18.67±4.243 GDM:16.04±3.712(mIU/l)]and the difference was signifance(P＜0.05).(4)The insulin resistance of index HOMA-IR gradully icrease from NGT group,GIGT group to GDM group(2.83±0.476,3.72±0.916,3.89±0.681),and the difference among NGT and two other groups was significant(P＜0.05).however,fhe difference between GIGT and GDM was ignored.Pearson correlation analyze indicates that HOMA-IR was correlated with the BMI of gestation(r=0.427 P＜0.05).(5)Pearson correlation analyze indicates that the serum RBP4 level positively correlated with gestational BMI(r=0.407 P＜0.001) and HOMA-IR(r=0.353 P＜0.05),fasting blood glucose(r=0.340 P=0.005),and did not correlate with gestational weeks,TC,TG.Multiple stepwise regression analysis indicate that gestational BMI and fasting blood glucose were dependently correlation with RBP4.Meanwhile,the correlation analysis manifestde that there was little relationship between FFA and fasting insulin in NGT group.however,FFA was negatively correlated with fasting insulin in GDM group(r=-0.340 P=0.042).Conclusions(1)The gestational BMI and insulin resistance in GIGT and GDM are higer than NGT,and obesity and overweight may degrade the sensitivity of insulin.Otherwise GDM subjects has increased insulin resistance and the potency of insulin secretion is difficult to offset the increase of insulin resistance in gestational women and result GDM.(2)Serum RBP4 levels significantly increased in GDM and overweight subjects and remarkably correlations with BMI and HOMA-IR.These reveal that RBP4 may contribute to the pathogenesis of gestational insulin resistance and GDM.(3)The serum level of FFA is highest in GDM group and negtively con-elation with FINS,suggesting that insulin resistance in gestation may relate to the increased FFA.However,there is no relationship between FFA and HOMA-IR and whether FFA contribute to the pathogenesis of insulin resistance in gestatinal women requirs advanced study and research.