Comparison on the plasma apolipoprotein-A5,insulin resistance and the secretion function of islet β-cell between the subjects with impaired fasting glucose and impaired glucose tolerance

Abstract

Objective To compare the levels of apolipoprotein A5(apoA5),insulin resistance(IR) and the secretion function of islet β-cells between subjects with impaired fasting glucose and impaired glucose tolerance,and to investigate the underlying pathogenesis.Methods Twenty-three patients with impaired fasting glucose(IFG group),24 with impaired glucose tolerance(IGT group),and 30 individuals with normal glucose tolerance(NGT group,as control) were enrolled in present study.All subjects underwent intravenous glucose tolerance test(IVGTT).Fasting apoA5 was assayed by ELISA.Fasting free fatty acid and the free fatty acid at 120 min after glucose loading were measured by colorimetry.Triglyeride(TG),high density lipoprotein cholesterol(HDL-C),low density lipoprotein cholesterol(LDL-C),total cholesterol(TC),fasting plasma glucose(FPG) and plasma glucose at 2 hours after glucose loading(2hPG) were determined.Homeostasis model assessments for insulin resistance(HOMA-IR) and for β-cell function(HOMA-B) were calculated.The relationships between apoA5 and those indexes mentioned above were analyzed.Results The levels of apoA5,AIR0-10,HOMA-B were significantly lower in IFG and IGT groups than in NGT group(P < 0.05),the levels of TG,FFA,2hFFA,HOMA-IR and FINS were significantly higher in IFG and IGT groups than in NGT group(P < 0.05).The levels of apoA5,AIR0-10,HOMA-B,FINS and 2hPG were significantly lower in IFG group than in IGT group(P < 0.05),the levels of TG,FFA,2hFFA,HOMA-IR and FPG increased significantly in IFG group than in IGT group(P < 0.05).ApoA5 was positively correlated with AIR0-10,HOMA-B and HDL-C,and negatively correlated with TG,FFA,2hFFA,LDL-C,FPG,2hPG,FINS,HOMA-IR,BMI and WHR.Stepwise multiple regression analysis showed that AIR0-10,TG,FFA and HOMA-IR were independent factors of apoA5.Conclusions The insulin resistance and impaired secretion function of islet β-cell are more severe in the subjects with IFG than those with IGT.It is conjectured that the subjects with IFG have lower level of plasma apoA5,thus by raising the level of plasma apoA5 might be a possible pathway to prevent and delay IFG to develop into diabetes mellitus.