丙氨酸转氨酶水平与胰岛素抵抗及胰岛β细胞功能的关系

目的 探讨血清丙氨酸转氨酶(ALT)水平与胰岛素抵抗(IR)及胰岛β细胞功能之间的关系.方法 收集2型糖尿病(T2DM)一级亲属351例,所有受试者均行75 g口服葡萄糖耐量试验(OGTT),检测体质指数(BMI)、腰臀比、血压、血脂、ALT、天冬氨酸转氨酶(AST)、血糖、真胰岛素(TI)及胰岛素原(PI),采用稳态模式( HOMA)评价胰岛素抵抗(HOMA-IR)及胰岛β细胞功能(HOMA-β).根据ALT四分间距,分为ALT 1组(＜12.9 U/L)、ALT 2组(12.9 ～ 17.3 U/L)、ALT 3组(17.4～24.2 U/L)、ALT4组(≥24.2 U/L).结果 随着ALT水平升高,ALT4组与ALT1组比较,BMI (26.3±2.9)kg/m2比(23.2±3.7) kg/m2,P＜0.01]、HOMA-IR1.93(1.21 ～ 3.26)比1.06(0.65 ～1.54),P＜0.01]、LnHOMA-β(2.00±0.32比1.87±0.28,P＜0.05)均升高,血压、血脂、血糖、TT、PI亦升高(P＜0.05或P＜0.01);随着代谢紊乱数目增多(无代谢紊乱与3～4个代谢紊乱数目组间比较),ALT 23.3( 16.3 ～ 37.6) U/L比14.3(10.3 ～18.5)U/L,P＜0.01]和AST 21.5( 18.3 ～32.8)U/L比17.9(15.5 ～22.1)U/L,P＜0.01]水平均升高;校正性别、年龄、BMI和腰臀比后血清ALT依然与血压、血脂、血糖、TI、2 h-PI、2 h-PI/TI、HOMA-IR和代谢紊乱数目呈正相关(r=0.117 ～0.236,P＜0.05或P＜0.01);多元逐步回归分析ALT与性别、甘油三酯、HOMA-IR、总胆固醇和2 h-PI呈独立正相关(P＜0.05或P＜0.01).结论 高ALT水平与代谢综合征、IR和胰岛β细胞功能代偿性增加密切相关,ALT水平独立于IR与代谢综合征相关.

Correlations of serum alanine aminotransferase and insulin resistance, pancreatic B-cell function

Objective To explore the correlations of serum alanine aminotransferase (ALT),insulin resistance and pancreatic B-cell function.Methods A total of 351 first-degree relatives of type 2 diabetes mellitus received a standard oral glucose tolerance test (OGTT) at our outpatient clinic.All subjects were analyzed for the parameters of body mass index ( BMI),waist-hip ratio,blood pressure ( BP),serum lipids,ALT,aspartate aminotransferase (AST),plasma glucose (PG),true-insulin and proinsulin.Homeostasis model assessment (HOMA) was applied to assess the status of insulin resistance and pancreatic B-cell function. They were divided into 4 groups according to the quartiles of ALT:ALT1 group (＜12.9 U/L),ALT2 group (12.9- 17.3 U/L),ALT3 group (17.4-24.2 U/L) and ALT4 group ( ≥24.2 U/L).The diagnosis of metabolic syndrome was made according to the definition of Chinese Diabetic Society.Results With the rising serum ALT levels (ALT4 vs ALT1 ),the levels of BMI (26.3 ± 2.9) kg/m2 vs (23.2±3.7) kg/m2,P＜0.01],HOMA-IR 1.93(1.21 -3.26) vs 1.06(0.65 -1.54),P＜0.01] and LnHOMA-beta (2.00 ±0.32 vs 1.87 ±0.28,P＜0.05) were elevated; BP,serum lipids,PG,true-insulin and proinsulin also increased ( P ＜ 0.05 or P ＜ 0.01 ).The levels of serum ALT 23.3(16.3-37.6) vs 14.3 (10.3-18.5) U/L,P＜0.01] and AST 21.5 (18.3-32.8) U/L vs 17.9( 15.5 -22.1 ) U/L,P ＜0.01 ] increased with the rising number of metabolic disorders (0 vs 3 -4 metabolic disorders).After adjustments for gender,age,BMI and waist-hip ratio,serum ALT were still positively correlated with BP,serum lipids,PG,fasting true-insulin,2 h proinsulin,2 h proinsulin/true-insulin,HOMA-IR and the numbers of metabolic disorder (r=0.117 -0.236,P＜0.05 or P＜0.01).After adjustments for gender,age,BMI,waist-hip ratio and HOMA-IR,the serum ALT level remained positively correlated with the numbers of metabolic disorders (r =0.120,P ＜ 0.05).Multiple stepwise regression analysis showed that triglyceride,HOMA-IR,total cholesterol and 2 h-proinsulin were the independent risk factors for the level of serum ALT ( P ＜ 0.05 or P ＜ 0.01 ).Conclusion The elevated levels of serum ALT are significantly correlated with metabolic syndrome,insulin resistance and compensatory increases of pancreatic B-cell function.Independently of insulin resistance,the serum ALT level is correlated with metabolic syndrome.