Impaired beta-cell function and insulin sensitivity in Japanese subjects with normal glucose tolerance

The development of type 2 diabetes mellitus is characterized by both impaired beta-cell function and increasing insulin resistance. To clarify the roles of them in developing type 2 diabetes, we evaluated insulin resistance by HOMA-IR and insulin secretion by HOMA beta-cell in 453 Japanese subjects whose fasting plasma glucose (FPG) and HbA(1c) levels were within normal range. HOMA beta-cell was found to decrease in the over 30 years groups, while HOMA-IR increased with body mass index (BMI). To analyze the reserve capacity of insulin secretion and insulin sensitivity, the 67 of them, who underwent a standard oral glucose tolerance test and were diagnosed with normal glucose tolerance (NGT), were divided into four degrees of BMI age-adjusted to 50 years. They were compared for insulinogenic index and ISI composite proposed by Matsuda and DeFronzo across the range of BMI. ISI composite was significantly less in the highest BMI group, while insulin secretion did not increase in the higher BMI groups. The subjects with higher BMI had remarkably lower insulinogenic indices than those with lower BMI. These data suggest that insulin secretory reserve is insufficient to compensate for increased insulin resistance in Japanese people with NGT at about 50 years of age.     

糖耐量受损者胰岛素敏感性及胰岛β细胞功能的研究

目的 研究糖耐量受损(IGT)者的胰岛素抵抗(IR)及胰岛β细胞功能变化。方法 选取正常糖耐量(NGT)、IGT、2型糖尿病(T2DM)者共34例，以高胰岛素正血糖钳夹技术测定IR，行静脉葡萄糖耐量试验评估胰岛β细胞分泌功能。结果 与NGT组相比，IGT组、T2DM组的IR显著升高；IGT组胰岛素第一时相分泌明显下降，空腹胰岛素(FIns)水平及第二时相分泌水平升高；T2DM组IR与IGT组处于同一水平，FIns较NGT组显著减少。结论 由NGT向IGT的演变过程中，IR和胰岛素分泌缺陷共同起作用。     

口服葡萄糖耐量试验仅1小时高血糖人群的β细胞功能

目的 研究OGTT 1h高血糖人群的β细胞功能. 方法 将1177例受试者分为正常糖耐量(NGT)、糖调节受损(IGR)和糖尿病(DM)三组.前两组再依据OGTT 1hPG水平分为NGTN、NGT1H和IGRN、IGR1H四个亚组.将IGR组再分为空腹血糖受损(IFG)组和糖耐量受损(IGT)组以及IFG+IGT组.HOMA-IR评估胰岛素敏感性,HOMA-β、△I_(30)/△G_(30)(IGI)、葡萄糖OGTT曲线下面积(AUCg)评估胰岛β细胞分泌功能. 结果 (1)NGTN和IGRN组分别比NGT1H和IGR1H组的IGI高(P<0.05);HOMA-IR、AUCg在两亚组间均无统计学差异.(2)NGT1H组比IFG组和IGT组具有较高的AUCg,其HOMA-β比IFG组高,三组间HOMA-IR和IGI差异无统计学意义. 结论 NGT1H人群已存在胰岛β细胞功能异常,可能为胰岛素分泌缺陷尤其是早期相分泌受损所致.     

Short-term low-dose growth hormone administration in subjects with impaired glucose tolerance and the metabolic syndrome: effects on beta-cell function and post-load glucose tolerance

OBJECTIVE: Modest elevations in circulating IGF-I levels have been suggested to protect against the development of glucose intolerance in insulin-resistant subjects. To further understand the interactions of GH and IGF-I on beta-cell function and post-load glucose tolerance in glucose-intolerant subjects predisposed to diabetes, we performed a pilot study in 12 subjects with impaired glucose tolerance and the metabolic syndrome using a low GH dose (1.7 microg/kg per day) known to increase endogenous IGF-I production. DESIGN: Fourteen daily GH or placebo injections in a double-blind cross-over study. METHODS: Baseline and post-treatment oral glucose tolerance tests were performed. The homeostasis model assessment and the insulinogenic index was used to estimate fasting insulin sensitivity (S(I)) and beta-cell function respectively, whereas changes in the incremental area under the curve were used to estimate post-load glucose tolerance (DeltaAUC(glu)) and post-load insulin levels (DeltaAUC(ins)). RESULTS: GH increased total IGF-I (P<0.02), free IGF-I (P<0.04) and fasting insulin (P<0.04) levels, but did not modify plasma IGF-binding proteins (IGFBPs)-1 and -3, fasting glucose, non-esterified fatty acid and C-peptide levels, and fasting S(I). After oral glucose intake, glucose tolerance improved (P<0.03), but post-load insulin levels and beta-cell function remained unchanged. CONCLUSION: Short-term low-dose GH administration induced fasting hyperinsulinaemia possibly by reducing insulin clearance but improved post-load glucose tolerance, suggesting that increased bioavailable IGF-I enhanced post-load S(I) without altering beta-cell function. Longer-term studies are required to ascertain whether these positive effects on post-load glucose tolerance and the preservation of beta-cell function can be sustained by this GH dose in these high-risk subjects.     

Pancreatic beta-cell function and insulin sensitivity in japanese subjects with impaired glucose tolerance and newly diagnosed type 2 diabetes mellitus

To clarify whether pancreatic beta-cell function and/or insulin resistance contributes to development of glucose intolerance in Japanese subjects, we investigated 551 subjects who underwent a 75-g oral glucose tolerance test (OGTT). Subjects were divided into 3 groups: normal glucose tolerance (NGT, n = 238), impaired glucose tolerance (IGT, n = 211), and newly diagnosed type 2 diabetes mellitus (n = 102). The diabetics were subdivided into 3 subgroups as follows: diabetes with normal fasting glucose (fasting plasma glucose [FPG] < 110 mg/dL), diabetes with impaired fasting glucose (FPG 110 to 125 mg/dL), and diabetes with diabetic fasting glucose (FPG >or= 126 mg/dL). Insulinogenic index as early-phase insulin secretion, homeostasis model assessment (HOMA-beta and HOMA-resistance), and 4 different formulas of insulin sensitivity index were assessed by plasma glucose and insulin concentrations obtained at fasting or during a 75-g OGTT. Both early-phase insulin secretion and insulin sensitivity were low even in the IGT stage compared with NGT. The transition from IGT to diabetes was accompanied by a progressive deterioration of insulin reserve as well as insulin resistance. During the further progression in diabetes, insulinogenic index decreased additionally, whereas declines in insulin sensitivity were relatively small. In conclusion, both impaired insulin secretion and insulin resistance may contribute to the underlying mechanisms of glucose intolerance in Japanese subjects.     

肝硬化患者口服葡萄糖耐量试验的变化

目的　了解口服葡萄糖耐量试验的血糖值与肝硬化患者肝功能状况的关系。方法　 3 8例肝硬化患者按Child Pugh肝功能分级 ,分为A级 ( 10例 )、B级 ( 14例 )和C级 ( 14例 )三组。 11例健康者为对照组。抽取空腹血 2ml后 ,行糖耐量试验 ,以葡萄糖氧化酶法测定血糖浓度。结果　肝硬化各组的基础血糖浓度与对照组比较无显著差异 ,60和12 0分钟血糖浓度均显著高于对照组 (P <0 .0 0 2～ 0 .0 5 ) ,且随着肝硬化严重程度的增加 (即A级→B级→C级 ) ,血糖浓度有增高的趋势。肝硬化各组的血糖12 0 /0 值均显著高于对照组 (P <0 .0 0 1～ 0 .0 0 2 ) ,并随着肝硬化严重程度的增加而增高。 12 0分钟血糖及血糖12 0 /0 值与血清白蛋白浓度呈显著负相关 (P <0 .0 0 1) ,与血清总胆红素浓度、凝血酶原延长时间、R151CG及Child Pugh肝功能评分呈显著正相关 (P <0 .0 0 1～ 0 .0 0 5 )。结论　口服葡萄糖耐量试验的 2小时血糖值及血糖12 0 /0 值与肝硬化患者的肝功能状况密切相关 ,是反映肝硬化患者肝功能状况的良好指标 ,有一定的临床应用价值。     

老年冠心病合并糖耐量减低患者不同血糖水平与冠状动脉病变的研究

目的探讨老年冠心病合并糖耐量减低患者不同血糖水平与冠状动脉病变的相关性。方法回顾分析经冠状动脉造影确诊冠心病的老年患者212例临床资料,根据口服葡萄糖耐量试验结果分为糖耐量正常(NGT)组64例,糖耐量减低(IGT)患者148例,又根据餐后2h血糖水平分为IGT1组50例,IGT2组58例和IGT3组40例,比较各组的冠状动脉病变支数、弥漫性病变状况以及冠状动脉病变Gensini总积分。结果与NGT组比较,IGT1组、IGT2组、IGT3组LDL-C水平、弥漫性病变比例、Gensini积分明显升高(P<0.05);IGT1组、IGT3组双支病变比例明显升高,IGT2组双支病变比例明显下降(P<0.05)。冠状动脉Gensini积分与餐后2h血糖呈正相关(r=0.512,P<0.05)。结论 IGT加重了冠状动脉病变程度。餐后2h血糖升高的患者是动脉粥样硬化的高危人群,对于此类人群应及时早期干预、治疗。     

Effects of pioglitazone on beta-cell function in metabolic syndrome patients with impaired glucose tolerance

OBJECTIVE: To determine the potential effects of pioglitazone on beta-cell function in metabolic syndrome patients with impaired glucose tolerance and probe into the possible mechanisms. RESEARCH DESIGN AND METHODS: Twenty-two subjects were treated with pioglitazone 30 mg/day for 4 months. At baseline and after treatment, each subject underwent an IVGTT. The acute insulin response (AIRg), the glucose disappearance rates (coefficients K) and the ratio of Deltainsulin/Deltaglucose (DeltaI/DeltaG) were calculated according to IVGTT results. Hyperglycemic clamp study was conducted to determine the second-phase insulin response, insulin sensitivity index (ISI) and glucose infusion rate (GIR). Euglycemic-hyperinsulinemic clamp study was made to measure the glucose disposal rate (GDR). Plasma glucose, free fatty acids (FFAs), serum insulin and proinsulin levels were measured. RESULTS: AIRg unchanged (P = 0.25) after treatment, whereas the values of coefficients K (P < 0.01) and DeltaI/DeltaG increased (P < 0.05). The second-phase insulin response and GIR were both demonstrated marked increments (P < 0.01 and P < 0.01, respectively). Pioglitazone therapy also resulted in improvement of ISI value (P < 0.05). And the increment of GDR during the euglycemic-hyperinsulinemic clamp was also significant (P < 0.01). Furthermore, a decrease in fasting proinsulin level was observed (P < 0.001). And plasma glucose, FFAs and serum insulin levels all declined. The increase of DeltaI1/DeltaG1 was positively correlated with the improvement of GDR (r = 0.536, P = 0.089). And a positive relationship was observed between the change in the second-phase insulin response and change in K value (r = 0.682, P = 0.021). CONCLUSIONS: Short-term pioglitazone therapy improved beta-cell dysfunction, the mechanism might involve the attenuation of insulin resistance.     

Effects of pioglitazone on beta-cell function in metabolic syndrome patients with impaired glucose tolerance

ObjectiveTo determine the potential effects of pioglitazone on beta-cell function in metabolic syndrome patients with impaired glucose tolerance and probe into the possible mechanisms.Research design and methodsTwenty-two subjects were treated with pioglitazone 30 mg/day for 4 months. At baseline and after treatment, each subject underwent an IVGTT. The acute insulin response (AIRg), the glucose disappearance rates (coefficients K) and the ratio of Δinsulin/Δglucose (ΔI/ΔG) were calculated according to IVGTT results. Hyperglycemic clamp study was conducted to determine the second-phase insulin response, insulin sensitivity index (ISI) and glucose infusion rate (GIR). Euglycemic–hyperinsulinemic clamp study was made to measure the glucose disposal rate (GDR). Plasma glucose, free fatty acids (FFAs), serum insulin and proinsulin levels were measured.ResultsAIRg unchanged (P = 0.25) after treatment, whereas the values of coefficients K (P < 0.01) and ΔI/ΔG increased (P < 0.05). The second-phase insulin response and GIR were both demonstrated marked increments (P < 0.01 and P < 0.01, respectively). Pioglitazone therapy also resulted in improvement of ISI value (P < 0.05). And the increment of GDR during the euglycemic–hyperinsulinemic clamp was also significant (P < 0.01). Furthermore, a decrease in fasting proinsulin level was observed (P < 0.001). And plasma glucose, FFAs and serum insulin levels all declined. The increase of ΔI₁/ΔG₁ was positively correlated with the improvement of GDR (r = 0.536, P = 0.089). And a positive relationship was observed between the change in the second-phase insulin response and change in K value (r = 0.682, P = 0.021).ConclusionsShort-term pioglitazone therapy improved beta-cell dysfunction, the mechanism might involve the attenuation of insulin resistance.     

Population impact of increased body mass index and attenuated beta-cell function on worsening of glucose metabolism in subjects with normal glucose tolerance: a pilot study

The population attributable fraction (PAF) of risk factors for the worsening of glucose metabolism in subjects with normal glucose tolerance (NGT) has not been calculated. Our aim was to obtain the PAF of increased body mass index (BMI) and attenuated beta-cell function (BCF) on worsening of glucose metabolism in subjects with NGT. We longitudinally analyzed 604 Japanese adults. The follow-up glucose tolerance status was determined 3.7 years later: 430 participants remained in the NGT category and 102 had progressed to impaired fasting glucose, 67 to impaired glucose tolerance, and 5 to diabetes mellitus. A product of ISI_Matsuda and Stumvoll-1, i.e., oral disposition index (DI_O), was used as a measure of BCF. The optimal cutoff baseline BMI and DI_O values for the prediction of the worsening of glucose metabolism were > 23.1 and < 7.299 kg/m², respectively. Isolated increased BMI (iBMI_HIGH), isolated low DI (iDI_OLOW), and “BMI_HIGH and DI_OLOW (BMI_HIGH/DI_OLOW)” were all independently related to the worsening, and the PAF values (95 % CI) for worsening due to iBMI_HIGH, iDI_OLOW, and BMI_HIGH/DI_OLOW were 12.9 (3.2–18.4) %, 10.9 (5.0–13.9) %, and 31.4 (22.7–36.3) %, respectively. As much as 55 % of the worsening of glucose metabolism in the NGT subjects was attributable to increased BMI and/or attenuated BCF. The optimal cutoff for BMI was as low as 23.1 kg/m² in this population. We believe that these data should form the basis of future public health strategies for the prevention of diabetes in Japan.     

HDL功能检测与冠状动脉斑块的相关性

目的针对正常高密度脂蛋白胆固醇(HDLC)水平(≥1.03 mmol/L)的冠心病患者,分析其血浆高密度脂蛋白(HDL)功能与冠状动脉狭窄及斑块性质的相关性。方法选取2015年10月至2017年12月在宜昌市中医医院接受64排螺旋CT冠状动脉造影(CTA)检查,并具有正常HDLC水平的疑似冠心病患者129例为研究对象,利用CTA检测进行冠状动脉狭窄程度及斑块性质分组,统计分析血浆HDL功能指标对氧磷酶1(PON1)活性及HDL氧化/抗氧化指数与其相关性。结果与非冠心病组比较,冠心病组HDLC水平、PON1活性下降,HDL氧化/抗氧化指数升高,显示为氧化状态,而ApoAI水平没有差异。随着冠状动脉狭窄程度增加,PON1活性逐渐降低,HDL氧化/抗氧化指数逐渐增高,而HDLC水平、ApoAI水平无明显差异。不同斑块性质分组分析显示,钙化斑块组PON1活性高于软斑块组及混合斑块组。PON1活性与HDLC、HDL氧化/抗氧化指数有一定相关性。结论HDL的功能检测中PON1活性对于冠心病的斑块性质及狭窄程度有良好的评价价值。     

Correlation between baseline serum 1,5-anhydroglucitol levels and 2-hour post-challenge glucose levels during oral glucose tolerance tests

Since there is increasing evidence that postprandial hyperglycemia is a risk factor for the development of macrovascular complications, it is important to predict postprandial hyperglycemia in the early stages of glucose intolerance, and routine medical checkups provide a good opportunity to do so. The aim of this study was to evaluate the usability of 1,5-anhydroglucitol (1,5-AG) in routine medical checkups. The subjects were 77 Japanese men who participated in a routine medical checkup. First, we performed 75 g oral glucose tolerance tests (OGTTs), and examined the changes in glucose and 1,5-AG levels measured at 0, 30, 60, 90, 120, and 180 minutes (min). 1,5-AG levels did not significantly change until 90 min after the glucose load. Second, a linear regression analysis showed an inverse correlation between the 2-hour post-challenge glucose (2h-PG) and baseline 1,5-AG levels during the OGTT (P = 0.001, r(2) = 0.13), and the correlation was still significant after adjustment for age (2h-PG = 170 + 0.83 × (age in years) - 3.23 × (1,5-AG), P = 0.002, adjusted r(2) = 0.12). Finally, to investigate the test characteristics of 1,5-AG levels as a predictor of a 2h-PG level ≥200 mg/dL, we plotted a receiver operating characteristic (ROC) curve. The area under the ROC curve was 0.78, and the maximal sum of sensitivity and specificity (78% and 72%, respectively) was obtained at a 1,5-AG cutoff level of <14.2μg/mL. We conclude that 1,5-AG values may provide an ancillary predictor of 2h-PG of 75 g OGTTs in routine medical checkups.     

Short-term exercise improves beta-cell function and insulin resistance in older people with impaired glucose tolerance

BACKGROUND: There is a high prevalence of diabetes and impaired glucose tolerance (IGT) in the older population. Normal aging is associated with insulin resistance and impaired insulin secretion, with greater defects in people with IGT. Short-term exercise has been found to increase insulin sensitivity, but little is known about acute exercise effects on beta-cell function in older people with IGT. METHODS: We assessed the effects of 7 consecutive days of supervised aerobic exercise (1 h/d at 60-70% heart rate reserve) in 12 sedentary older people with IGT. Screening included oral glucose tolerance test, stress/maximal O(2) uptake test, and dual-energy x-ray absorptiometry scan. Participants had a frequently sampled iv glucose tolerance test at baseline and 15-20 h after the seventh exercise session. Insulin sensitivity (S(I)), glucose disappearance constant (Kg, a measure of iv glucose tolerance), acute insulin response to glucose (AIRg), and disposition index (AIRg x S(I)), a measure of beta-cell function in relation to insulin resistance, were calculated. RESULTS: Exercise was well tolerated. Body weight, fasting glucose, fasting insulin, and iv glucose tolerance were unchanged with exercise. S(I) increased by 59%, AIRg decreased by 12%, and disposition index increased by 31%. There was no significant change in fasting lipid, catecholamine, leptin, or adiponectin levels. CONCLUSIONS: Short-term exercise not only improved insulin resistance but also significantly enhanced beta-cell function in older people with IGT. These effects of short-term exercise on beta-cell function cannot be explained by changes in body weight or circulating levels of lipids, leptin, adiponectin, or catecholamines.     

纳格列奈-口服葡萄糖耐量试验对检测正常人胰岛β细胞功能的评价

目的 优化纳格列奈-口服葡萄糖耐量试验(NG-OGTT)评估胰岛β细胞功能的方法.方法 对24例健康志愿者进行NG-OGTT,测定各设定时间点(-15、0、10、20、30、45、60及120 min)的胰岛素和血糖水平.胰岛素测定采用放射免疫法.观察NG-OGTT中胰岛素释放的峰值,胰岛素释放倍增值(MVI),各设定时间点的胰岛素释放曲线下面积(AUCIns)、胰岛素释放速率(IRV)、胰岛素净增值与血糖净增值的比值(△I/△G),筛选出NG-OGTT中最能反映胰岛β细胞分泌与储备功能的时间点.结果 (1) 正常人在NG-OGTT中反映胰岛β细胞早期相分泌功能的胰岛素释放峰值(90.50 mU/L)与IRV(2.75 mU·L-1·min-1)的达峰时间均在糖负荷后30 min;(2)其△I/△G的达峰时间虽在糖负荷后45 min(56 mU/mmol),但45 min时该值的升高主要由血糖的快速降低引起;(3) 反映β细胞储备功能的MVI(18.8)的达峰时间亦在糖负荷后30 min;(4) 其AUCIns在60 min时与120 min具有显著性相关(r=0.901,P=0.000).结论 糖负荷后采用-15、0、30和60 min 4个采血点,能反映β细胞早期相分泌功能及储备功能,方法简便.     

糖耐量减低人群胰岛β细胞功能的变化

131例正常糖耐量,120例糖耐量减低和107例2型糖尿病患者的研究显示,胰岛素原(PI)呈递增,而胰岛素敏感指数、HOMA-β和△I30/△G30呈递减倾向。肥胖组HOMAβ-,胰岛素、C肽和胰岛素原的曲线下面积均高于非肥胖组。     

Rosiglitazone improves insulin sensitivity and glucose tolerance in subjects with impaired glucose tolerance

OBJECTIVE: This study was designed to evaluate the effects of rosiglitazone (ROS) on insulin sensitivity, beta-cell function, and glycaemic response to glucose challenge and meal in subjects with impaired glucose tolerance (IGT). METHODS: Thirty patients with IGT (ages between 30 and 75 years and BMI (body mass index) < or = 27 kg/m2) were randomly assigned to receive either placebo (n = 15) or ROS (4 mg/day) (n = 15). All participants underwent a 75-g oral glucose tolerance test (OGTT), meal test, and frequently sampled intravenous glucose tolerance test (FSIGT) before and after the 12-week treatment. RESULTS: After 12 weeks of ROS treatment, there were significant increases in total cholesterol (TC) (4.25 +/- 0.22 vs 4.80 +/- 0.17 mmol/l, P < 0.001), high-density lipoprotein cholesterol (HDL-C) (1.25 +/- 0.07 vs 1.43 +/- 0.06 mmol/l, P < 0.05), and low-density lipoprotein cholesterol (LDL-C) (2.70 +/- 0.15 vs 3.37 +/- 0.17 mmol/l, P < 0.05) without changes in triglyceride concentration, TC/HDL-C and LDL-C/HDL-C ratio. Although the acute insulin response (AIR) to intravenous glucose and disposition index (measured as the ability of pancreatic beta-cell compensation in the presence of insulin resistance) remained unchanged, the insulin sensitivity (SI) and glucose effectiveness (SG) were remarkably elevated (0.38 +/- 0.06 vs 0.54 +/- 0.09 x 10(-5) min(-1)/pmol, P < 0.05; 0.017 +/- 0.002 vs 0.021 +/- 0.001 min(-1), P < 0.05, respectively) in the ROS group. The glucose, insulin, and c-peptide areas under curve (AUC) in response to OGTT and the glucose and insulin AUC during meal were significantly ameliorated in the ROS group. Five out of 15 (33%) and two out of 15 (13%) subjects treated with ROS and placebo, respectively, reversed to normal response during OGTT (P < 0.05). CONCLUSION: Rosiglitazone treatment significantly improved insulin resistance and reduced postchallenge glucose and insulin concentrations in patients with impaired glucose tolerance without remarkable effects on beta-cell secretory function.