不同糖代谢状态人群胰岛素抵抗和胰岛β细胞功能研究

目的探讨从正常糖耐量到糖尿病(DM)不同糖代谢水平,胰岛素抵抗(IR)与胰岛β细胞功能的演变.方法青岛市区30～74岁的正常糖耐量(NGT)447例;空腹血糖受损(IFG)142例;糖耐量受损(IGT)93例;IFG合并IGT(IFG+IGT)42例;新诊DM 153例.采用HOMA-IR评价IR,HOMA-β、ΔI30/ΔG30分别评价基础状态下及糖负荷后的早期胰岛β细胞功能.结果 IFG组HOMA-IR为1.14±0.06,明显高于NGT组的0.93±0.03(P＜0.05),IFG组HOMA-β为4.53±0.06,低于NGT组5.10±0.04(P＜0.05),两组间△I30/△G30差异无显著性(4.86±0.11 vs 4.99±0.11);IGT组HOMA-IR为1.12±0.07,明显高于NGT(P＜0.05),两组间HOMA-β差异无显著性,IGT组△I30/△G30 为4.62±0.14,低于NGT组的4.99±0.11(P＜0.05);DM组HOMA-IR为1.55±0.05,明显高于NGT、IGT和IFG组(P＜0.05),DM组HOMA-β和△I30/△G30 分别为3.94±0.06、3.93±0.12,明显低于其他各组(P＜0.05),DM组基础与糖负荷后的胰岛β细胞功能均明显受损.结论 IFG患者主要表现β细胞功能缺陷,IGT为胰岛素早期分泌受损,DM患者兼有严重的IR和β细胞缺陷.从NGT到DM,随着糖代谢的不断恶化,IR逐渐加重,胰岛β细胞功能进行性减退,最终发生胰岛β细胞功能衰竭.     

沈阳地区糖耐量受损者胰岛β细胞功能和胰岛素抵抗

2003年美国糖尿病学会（ADA）糖尿病诊断和分型专家委员会提出将空腹血糖受损（IFG）的空腹血糖（FPG）切点由6．1mmol／L下调至5．6mmol／L。按新标准划分的中国的糖代谢异常者是否存在着糖尿病前期阶段的代谢特征？本研究运用能精确测定胰岛素抵抗程度的正血糖高胰岛素钳夹技术和能反映胰岛素早期分泌缺陷的静脉葡萄糖耐量试验（IVGTT），来研究比较新旧切点下不同糖耐量的胰岛素抵抗程度和β细胞分泌功能的异同。     

空腹血糖受损人群胰岛素抵抗和胰岛β细胞功能特点分析

目的　探讨我国空腹血糖受损 (IFG)人群胰岛素抵抗 (IR)和胰岛 β细胞功能的特点。 方法　根据口服 75g葡萄糖耐量试验将 13 0 45例≥ 2 5岁的中国人群分为糖耐量正常 (NGT)组 ,IFG组 ,糖耐量低减 (IGT)组和IFG/IGT组 ,利用HOMA胰岛素抵抗指数 (HOMA IR)、HOMAβ细胞功能指数 (HBCI)、第 1和第 2时相胰岛素释放指数等进行组间比较和多因素分析。结果　 (1)与NGT组相比 ,IFG组体重指数、腰臀围比值、空腹胰岛素、血清甘油三酯、血压、HOMA IR明显升高 ,而HBCI、第 1和第 2时相胰岛素释放指数明显降低 (P <0 .0 1～P <0 .0 0 1)。Logistic回归分析显示 :HOMA IR与IFG发生的一致性高达 0 .66～ 0 .79(均P <0 .0 0 1)。 (2 )与IGT组相比 ,IFG组OGTT 2h胰岛素水平显著低于IGT(P <0 .0 0 1)。Logistic回归分析显示 :HOMA IR、第 1和第 2时相胰岛素分泌指数与IFG发病显著正相关 ,HBCI与IFG发病显著负相关 ,各方程预测IFG发生的一致性高达 0 .5 6～ 0 .74(均P <0 .0 0 1)。结论　IFG者空腹状态下的胰岛素敏感性和 β细胞功能均较NGT和IGT者差 ,而糖负荷后的胰岛素分泌状态比NGT者差 ,但明显好于IGT者 ,因此 ,IFG者可能存在空腹及餐后IR和 β细胞功能的分离状态 ,是一组有别于IGT的糖稳态受损人群。     

孕妇在不同糖耐量状态下胰岛素抵抗和胰岛β细胞功能的改变

目的 研究孕妇在不同糖耐量状态下胰岛素抵抗(IR)和胰岛β细胞功能的改变.方法 分析51例妊娠糖尿病(GDM)孕妇、45例糖耐量低减(GIGT)孕妇和119例糖耐量正常(NGT)孕妇的IR和胰岛β细胞分泌功能,采用稳态模式胰岛素抵抗指数(HOMA-IR)评价胰岛素抵抗,稳态模式胰岛B细胞功能指数(HBCI)和30分钟净增胰岛素/30分钟净增血糖(△130/△G30)评价胰岛β细胞分泌功能.结果 从NGT、GIGT到GDM,HOMA-IR呈递增,而HBCI和△DO/△G30呈递减倾向,差异均有统计学意义(P＜0.05～0.01);HBCI、△130/△G30与2hPG呈明显负相关(r分别=0.144,0.258,P均＜0.01);HBCI与△130/△G30呈明显正相关(r=0.144,P＜0.05).结论 妊娠期胰岛素抵抗增加和胰岛β细胞分泌功能下降是GDM的发病原因,且在GIGT阶段胰岛素早期分泌功能已受损.     

不同糖耐量者血清游离脂肪酸与胰岛素抵抗的关系

以口服糖耐量试验(OGTT)确定受试者为正常人,糖耐量低减(IGT)和2型糖尿病,并测定空腹和OGTT 2h的游离脂肪酸(FFA)、血糖和胰岛素浓度,计算胰岛素敏感指数(IAI)。2型糖尿病和IGT患者的空腹和OGTT 2 h FFA、血糖和胰岛素浓度均明显高于正常组(均P<0.05),IAI均明显低于正常对照组(均P<0.01)。空腹及OGTT 2 h FFA与IAI之间呈显著负相关(分别为r=-0.38,P<0.01和r=-0.32,P<0.05),体重指数与IAI呈显著负相关(r=-0.39,P<0.05)。上述结果提示脂毒性在2型糖尿病的发病机制中有重要作用。     

游离脂肪酸与胰岛素抵抗、胰岛B细胞功能障碍述要

游离脂肪酸在糖耐量异常和2型糖尿病发生中发挥着重要作用.现就游离脂肪酸增多与胰岛素抵抗和胰岛B细胞功能障碍关系进行综述.     

社区老年正常糖耐量人群胰岛素抵抗和胰岛β细胞功能研究

入选老年正常糖耐量(NGT)者2 929名、糖耐量受损(IGT)者448例和2型糖尿病(T2DM)患者1143例.NGT者根据空腹血糖(FBG)四分位数和十分位数分别分为4个亚组和10个亚组.结果显示,中国老年NGT人群随着血糖升高,空腹胰岛素和稳态模型评估的胰岛素抵抗指数(HOMA-IR)逐渐升高.以HOMA-IR的75％位点2.15为切割点,≥2.15者在4个NGT亚组、IGT组、T2DM组中的比例逐渐升高;超重或肥胖、高血压和高甘油三酯组HOMA-IR≥2.15比例明显升高;相反,中国老年NGT人群中随着血糖升高,稳态模型评估的胰岛β细胞功能指数(HOMA-β)逐渐下降,以HOMA-β 25％位点41.79为切割点,＜41.79者在4个NGT亚组、IGT组、T2DM组中的比例逐渐升高;非肥胖、正常血压和正常甘油三酯血症患者HOMA-β＜41.79的比例明显升高.logistic回归分析显示年龄和处置指数是影响老年2型糖尿病独立的危险因素.     

黑龙江省不同糖代谢人群胰岛素抵抗和胰岛β细胞功能调查

通过评价143例空腹血糖受损患者,333例糖耐量受损患者,113例空腹血糖受损合并糖耐量受损患者,265例糖尿病患者与2 204名正常糖调节者的稳态模型评估的胰岛素抵抗指数(HOMA-IR)和稳态模型评估的胰岛β细胞功能指数(HOMA-β)情况,发现从正常糖调节到糖尿病.胰岛素抵抗逐渐加重[In(HOMA-IR):0.27±0.26、0.41±0.24、0.59±0.30],胰岛β细胞功能进行性减退[In(HOMA-β):2.00±0.27、1.94±0.22、1.76±0.30].空腹血糖受损、糖耐量受损、空腹血糖受损合并糖耐量受损三者可能具有不同的发病机制,提示在预防其发展为糖尿病时,应采取不同措施.     

原发性高血压患者胰岛β细胞功能和胰岛素抵抗研究

目的:探讨不同糖代谢状态下原发性高血压(EH)患者空腹胰岛β细胞功能(FBCI)和胰岛素抵抗(IR)状况。方法:选取符合入选标准的150例EH患者,分为伴糖尿病组与不伴糖尿病组,以健康者50例作为对照组,分别进行OGTT试验和同步胰岛素释放试验,计算胰岛素抵抗指数(HOMA-IR)和FBCI。结果:不伴糖尿病的EH患者FBCI和HOMA-IR高于对照组;伴糖尿病的EH患者FBCI和HOMA-IR显著升高,与不伴糖尿病的EH者比较,差异有统计学意义(P<0.01)。结论:不同糖代谢状态下EH患者均存在糖代谢紊乱和IR,简单的FBCI计算公式不能够反映真实EH患者的胰岛β细胞功能。     

胰岛β细胞的胰岛素抵抗

近年发现胰岛β细胞同样具有胰岛素的信号转导途径，同时也存在胰岛素抵抗。β细胞自身的胰岛素抵抗会导致葡萄糖刺激的一相胰岛素分泌异常，抑制β细胞增殖，促进β细胞凋亡。肥胖可以促进胰岛β细胞胰岛素抵抗的发生发展。胰岛β细胞自身胰岛素抵抗可能是2型糖尿病发病的中心环节。     

Comparison of measured and estimated indices of insulin sensitivity and beta cell function: impact of ethnicity on insulin sensitivity and beta cell function in glucose-tolerant and normotensive subjects

Type 2 diabetes mellitus is the result of an imbalance between insulin sensitivity and beta cell function. Although the assessment of these 2 parameters is critical for various studies, the current methods are time consuming and labor intensive. Recently, new estimated indices have been proposed. We examined the impact of ethnicity on the indices of insulin sensitivity and beta cell function measured from the hyperglycemic clamp and compared the results to the estimated indices, proposed by Matsuda and DeFronzo and Stumvoll et al., from a standard oral glucose tolerance test in 105 healthy, glucose-tolerant, and normotensive subjects from 4 ethnic groups. Among the ethnic groups, differences were noted in the measured insulin sensitivity (P = 0.0006) and beta cell function (P = 0.006 for the first phase insulin response, P = 0.0002 for the second phase insulin response). Although the estimated indices correlated with the measured indices (r(2) = 0.5184--0.3014), the estimated indices barely detected the differences among the ethnic groups. Multivariate analysis confirmed that ethnicity had an independent impact for the measured indices, but had only a modest impact on the estimated insulin sensitivity indices and had no impact on the estimated indices of beta cell function. We conclude that although the estimated indices of insulin sensitivity and beta cell function from the oral glucose tolerance test correlated with the measured ones in a wide spectrum of healthy, glucose-tolerant, and normotensive subjects, they were much less likely to detect the differences than measured ones among the ethnic groups.     

Acute elevation of free fatty acid levels leads to hepatic insulin resistance in obese subjects

Raised levels of free fatty acids (FFA) compete with glucose for utilization by insulin-sensitive tissues, and, therefore, they may induce insulin resistance in the normal subject. The influence of experimental elevations in FFA levels on glucose metabolism in native insulin-resistant states is not known. We studied seven women with moderate obesity (63% above their ideal body weight) but normal glucose tolerance with the use of the insulin clamp technique with or without an infusion of Intralipid + heparin. Upon raising plasma insulin levels to approximately 60 microU/mL while maintaining euglycemia, whole body glucose utilization (3H-3-glucose) rose similarly without (from 66 +/- 7 to 113 +/- 11 mg/min m2, P less than .02) or with (from 70 +/- 7 to 137 +/- 19 mg/min m2, P less than .02) concomitant lipid infusion. In contrast, endogenous glucose production was considerably (73%) suppressed (from 66 +/- 7 to 15 +/- 8 mg/min m2, P less than .001) during the clamp without lipid, but declined only marginally (from 70 +/- 7 to 48 +/- 7 mg/min m2, NS) with lipid administration. The difference between the control and the lipid study was highly significant (P less than .02), and amounted to an average of 3.8 g of relative glucose overproduction during the second hour of the clamp. Blood levels of lactate rose by 34 +/- 15% (.1 greater than P greater than .05) in the control study but only by 17 +/- 10% (NS) during lipid infusion. Blood pyruvate concentrations fell in both sets of experiments (by approximately 45% at the end of the study) with similar time courses.(ABSTRACT TRUNCATED AT 250 WORDS)     

代谢综合征与自由脂肪酸的关系

目的探讨代谢综合征及其不同组分与自由脂肪酸（free fatty acid,FFA）的关系。方法1999年9月至10月,在北京市自然人群中采用分层随机抽样方法进行危险因素的横断面调查。分析了997名35～64岁男女两性的血浆FFA浓度与代谢综合征及其组分的关系。结果（1）代谢综合征的患病率随着FFA的升高而升高。（2）采用多因素logistic回归调整了年龄、性别、吸烟、饮酒、体重指数（BMI）和胰岛素抵抗后,FFA四分位分层的第二、三、四层的OR值分别为3．1、3．1和4．1,均有统计学意义（P 〈 0．01）。（3）在相关分析中,FFA与甘油三酯（TG）、血糖、收缩压、舒张压和腰围的相关均有统计学意义（P 〈 0．01）,其中与TG的相关性最强,与血糖的相关性其次。FFA与高密度脂蛋白胆固醇（HDL-C）的相关无统计学意义。（4）用多因素logistic分析调整了BMI和胰岛素抵抗等因素后,FFA仍与代谢综合征5个组分中的腹部肥胖、高TG血症、高血压、高血糖4个组分相关,与低HDL-C血症的关系无统计学意义。（5）调整了FFA和BMI等因素的作用后,胰岛素抵抗也与代谢综合征及其5个组分中的腹部肥胖、高TG血症、高血糖和低HDL-C血症相关,而与高血压的关系无统计学意义。结论FFA与代谢综合征和代谢综合征5个组分中的腹部肥胖、高TG血症、高血压、高血糖4个组分均相关,提示FFA是代谢综合征的发病基础或危险因素之一。FFA和胰岛素抵抗可能通过不同的机制共同导致代谢综合征。     

Insulin regulation of plasma free fatty acid concentrations is abnormal in healthy subjects with muscle insulin resistance

This study evaluated the ability of insulin to regulate free fatty acid (FFA) concentrations in healthy nondiabetic subjects selected to be either insulin-resistant or -sensitive on the basis of insulin-mediated glucose disposal by muscle. Comparisons of steady-state plasma glucose (SSPG), insulin (SSPI), and FFA concentrations were made at the end of 3 infusion periods: (1) under basal insulin conditions (approximately 10 microU/mL), (2) in response to isoproterenol-induced stimulation of lipolysis at the same basal insulin concentration, and (3) following inhibition of isoproterenol-induced lipolysis by a 2-fold increase in the insulin concentration. The results showed that steady-state FFA concentrations were significantly higher under basal conditions (360 +/- 73 v 158 +/- 36 microEq/L, P = .02), in response to isoproterenol-induced lipolysis (809 +/- 92 v433 +/- 65 microEq/L, P = .005), and following insulin inhibition of isoproterenol-induced lipolysis (309 +/- 65 v 159 +/- 37 microEq/L, P = .06). These differences were found despite the fact that SSPG concentrations were also higher in insulin-resistant individuals during all 3 infusion periods. These results demonstrate that the ability of insulin to regulate plasma FFA concentrations is impaired in healthy subjects with muscle insulin resistance, indicating that insulin-resistant individuals share defects in the ability of insulin to stimulate muscle glucose disposal and to inhibit adipose tissue lipolysis.     

Association between insulin resistance and reduced coronary vasoreactivity in healthy subjects

BACKGROUND: Insulin resistance appears to be an important risk factor for coronary artery disease. OBJECTIVE: To examine the role of insulin resistance on coronary vasoreactivity in healthy subjects. PATIENTS AND METHODS: Myocardial blood flow was quantitated using positron emission tomography and oxygen-15-labelled water in 10 healthy, nonobese men. The perfusion measurements were performed basally and during adenosine infusion, which has been used as a measure of coronary vasoreactivity. After perfusion measurements were taken, whole-body glucose uptake was determined using the euglycemic hyperinsulinemic clamp technique. RESULTS: Basal myocardial blood flow was 0.89+/-0.21 mL.g(-1).min(-1); adenosine significantly increased the flow to 4.00+/-1.13 mL.g(-1).min(-1). Adenosine-stimulated myocardial blood flow was inversely associated with fasting serum insulin concentration (r=-0.69, P<0.05). Concordantly, hyperemic blood flow was associated with whole-body glucose uptake during euglycemic hyperinsulinemic conditions (r=0.64, P<0.05). Basal myocardial blood flow was not affected by insulin resistance. CONCLUSION: The results of the present study demonstrate the novel finding that insulin resistance is associated with reduced coronary vasoreactivity, even in healthy subjects.     

Association between insulin resistance and plasma amino acid profile in non‐diabetic Japanese subjects

Aims/Introduction

Elevation of the branched-chain amino acids (BCAAs), valine, leucine and isoleucine; and the aromatic amino acids, tyrosine and phenylalanine, has been observed in obesity-related insulin resistance. However, there have been few studies on Asians, who are generally less obese and less insulin-resistant than Caucasian or African-Americans. In the present study, we investigated the relationship between homeostasis model assessment of insulin resistance (HOMA-IR) and plasma amino acid concentration in non-diabetic Japanese participants.

Materials and Methods

A total of 94 healthy men and women were enrolled, and plasma amino acid concentration was measured by liquid chromatography/mass spectrometry after overnight fasting. The associations between HOMA-IR and 20 amino acid concentrations, and anthropometric and clinical parameters of lifestyle-related diseases were evaluated.

Results

The mean age and body mass index were 40.1 ± 9.6 years and 22.7 ± 3.9, respectively. Significantly positive correlations were observed between HOMA-IR and valine, isoleucine, leucine, tyrosine, phenylalanine and total BCAA concentration. Compared with the HOMA-IR ≤ 1.6 group, the HOMA-IR > 1.6 group showed significantly exacerbated anthropometric and clinical parameters, and significantly elevated levels of valine, isoleucine, leucine, tyrosine, phenylalanine and BCAA.

Conclusions

The present study shows that the insulin resistance-related change in amino acid profile is also observed in non-diabetic Japanese subjects. These amino acids include BCAAs (valine, isoleucine and leucine) and aromatic amino acids (tyrosine and phenylalanine), in agreement with previous studies carried out using different ethnic groups with different degrees of obesity and insulin resistance.     

体重减轻对肝脏中游离脂肪酸摄取和肝胰岛素抵抗的影响

肥胖通常与肝脏中脂肪积聚有关,而肝脏脂肪又与全身及肝脏局部的胰岛素抵抗有关.低热卡饮食可改善脂肪肝,增加胰岛素敏感性.     

体重减轻对肝脏中游离脂肪酸摄取和肝胰岛素抵抗的影响

肥胖通常与肝脏中脂肪积聚有关,而肝脏脂肪又与全身及肝脏局部的胰岛素抵抗有关.低热卡饮食可改善脂肪肝,增加胰岛素敏感性.