Pharmacological treatment of insulin resistance at two different stages in the evolution of type 2 diabetes: impact on glucose tolerance and beta-cell function

The purpose of this study was to compare the impact of treating insulin resistance with a thiazolidinedione drug before vs. at the onset of diabetes on glucose levels and beta-cell function.Nondiabetic Hispanic women of Mexican or Central American descent with prior gestational diabetes mellitus (GDM) were randomized to troglitazone (early intervention), 400 mg/d, or placebo (later intervention). Women who developed diabetes were placed on open-label troglitazone. Glucose tolerance, insulin resistance, and beta-cell function were measured at randomization, at the diagnosis of diabetes, and 8 months post trial to determine the long-term impact of the two treatment strategies on glucose levels and beta-cell function. During a mean follow-up of 4.3 yr between baseline and posttrial tests, glucose tolerance (oral glucose tolerance test glucose area, P = 0.04) and insulin resistance (MINMOD SI, P = 0.02) worsened more in women randomized to late intervention (n = 69) than to early intervention (n = 57). Insulin secretion (acute insulin response in the iv glucose tolerance test, P = 0.09) and beta-cell compensation for insulin resistance (disposition index, P = 0.07) also tended to worsen more in the late intervention group. Among women in the late intervention group who developed diabetes, oral glucose tolerance test glucose area (P = 0.0001) and beta-cell function (P < or = 0.04) deteriorated significantly during development of diabetes on placebo and then did not change significantly (P > 0.50) during treatment with troglitazone and posttreatment washout. In high-risk Hispanic women, amelioration of insulin resistance can stabilize glycemia at the time diabetes develops. These findings highlight the role of insulin resistance in the genesis of progressive beta-cell dysfunction during the evolution of type 2 diabetes.     

Influence of insulin treatment on insulin sensitivity in insulin requiring type 2 diabetes patients

Insulin resistance in type 2 diabetes subjects was investigated before and 6 months after insulin administration in 43 type 2 diabetes patients (28 females and 15 males). Their age was 56.1+/-8.6 years, diabetes duration 11.7+/-6.8 years, BMI 29.5+/-5.3 kg/m2. All patients were on maximal dosage of oral hypoglycaemic agents and had poor metabolic control (HbA1c 11.2+/-1.6%). Insulin sensitivity was measured by euglycaemic clamp (insulin infusion rate 1 mU kg-1 min-1). The glucose disposal rate (M-value) was considerably lower in patients (2.4+/-1.6 mg kg-1 min-1, 0.2-8.1) compared with healthy subjects (7.1+/-0.2 mg kg-1 min-1, p<0.01). M-value was strongly associated with WHR (r=-0.41, p<0.05). The patients with poorest insulin sensitivity had the highest level of total cholesterol (r=-0.41, p=0.02) and LDL-cholesterol (r=-0.38, p=0.03). After 6 months of insulin treatment BMI was 30.3+/-4.2 kg/m2 (p<0.05), mean weight increase was 2.7+/-0.8 kg. M-value was substantially increased to 4.5+/-2.3 mg kg-1 min-1 (p<0.001), the degree of improvement depended on basal insulin sensitivity (r=-0.55, p<0.01). HbA1c was reduced to 7.7+/-1.4% (p<0.01), the correlation M-value with change of HbA1c (r=-0.59, p<0.01) was shown. Total cholesterol decreased from 6.3+/-1.1 to 5.4+/-1.1 mmol/l, LDL-cholesterol from 4.1+/-1.1 to 3.4+/-1.0 mmol/l, triglycerides from 2.6+/-1.6 to 1.6+/-0.7 mmol/l (p<0.001). In conclusion, insulin treatment of type 2 diabetes patients leads to decrease in insulin resistance due to reduction in glucose toxicity and plasma atherogenicity despite weight gain.     

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.     

罗格列酮对初发2型糖尿病患者糖耐量的影响及相关因素

113例初发2型糖尿病患者经罗格列酮治疗16周,46例糖耐量缓解,67例未缓解.与未缓解组比,缓解组年龄较轻、病程较短、体重指数较小,基线及治疗后的稳态模型评估的胰岛β细胞指数(HOMA-β)、早时相胰岛素分泌指数(△I30/△G30)好于未缓解组,基线胰岛素抵抗指数(HOMA-IR)低于未缓解组(均P＜0.05).提示罗格列酮通过改善2型糖尿病患者的稳态模型评估的胰岛素抵抗而促进β细胞分泌功能及糖耐量恢复,影响糖耐量缓解的因素包括年龄、病程、体重指数、HbA1C、β细胞分泌功能及胰岛素抵抗程度.     

Improved beta-cell function after intensive insulin treatment in severe non-insulin-dependent diabetes

In Type II, non-insulin-dependent diabetes, insulin secretion is often reduced to the point where oral hypoglycaemic agents fail to control the plasma glucose level. We studied 12 patients (age 41-66 years; 4 lean, 8 obese) with Type II diabetes mellitus for 1-25 years who were uncontrolled despite maximal dose glibenclamide and metformin. After withdrawal of medication, blood glucose control was determined by measuring glucose before and 2 h after each meal for 48 h, and beta-cell function by insulin or C-peptide response to glucagon and to iv glucose. Following these tests, intensive insulin treatment (CSII) was initiated, and near-euglycaemia (mean of 7 daily glucose determinations less than 7.7 mmol/l) was maintained for 16.6 +/- 1.5 days, at which time the tests were repeated. Mean daily insulin requirement was 61 +/- 9 IU (0.81 +/- 0.09 IU/kg). Glucose control was improved after cessation of CSII (mean glucose 12.7 +/- 0.6 mmol/l after vs 20 +/- 1.5 mmol/l before, P less than 0.005). Maximum incremental C-peptide response improved both to glucagon (214 +/- 32 after vs 134 +/- 48 pmol/l before, P = 0.05) and to glucose iv bolus injection (284 +/- 53 vs 113 +/- 32 pmol/l, P less than 0.05). Peak insulin response, measured after iv glucose infusion, also tended to be higher in the post-CSII test (42 +/- 18 vs 22 +/- 5.6 mU/l). Basal and stimulated proinsulin concentrations were high relative to C-peptide levels during the pre-treatment period, but returned to normal after CSII.(ABSTRACT TRUNCATED AT 250 WORDS)     

Staged diabetes management according to individual patient insulin resistance and beta-cell function ameliorates glycaemic control in type 2 diabetes mellitus

Objective The current consensus algorithm for management of type 2 diabetes is based on the fasting glucose concentration and glycated haemoglobin A_1c (HbA_1c) level. We applied a new therapeutic strategy by assessing insulin secretion and insulin resistance, in addition to glucose concentrations in individual patients. Design and patients We enrolled 193 patients with type 2 diabetes. The patients were assigned to one of six groups according to insulin secretion measured by the serum fasting C‐peptide concentration and insulin resistance measured by an insulin tolerance test (ITT). The two groups were treated differently: 108 patients were treated using a new staged diabetes management (SDM) strategy and 85 patients continued with conventional therapy. Measurements We compared metabolic variables in the two groups at baseline and 12 months after enrolment. Results In patients treated with the SDM strategy, fasting glucose concentration decreased from 9·8 ± 2·1 to 8·2 ± 1·7 mmol/l (P < 0·001). Postprandial 2‐h glucose concentration decreased from 14·19 ± 3·34 to 12·27 ± 3·24 mmol/l (P < 0·001). HbA_1c level decreased from 8·37 ± 1·42% to 7·72 ± 1·39% (P < 0·001). About 43% of the new SDM group achieved an HbA_1c of < 7·0% compared with 25% of patients in the conventional treatment group. Conclusions The new SDM strategy, based on individual data on insulin resistance and insulin secretion, may provide valuable clinical benefits in non‐obese Korean patients with type 2 diabetes.     

双相门冬胰岛素强化治疗对初诊2型糖尿病患者胰岛β细胞功能的影响

目的观察预混双相门冬胰岛素30(BIAsp30)对初诊2型糖尿病患者血糖控制及其对胰岛β细胞功能的影响。方法对122例初诊2型糖尿病患者,分为BIAsp30治疗组和口服降糖药(OHD)治疗组,治疗6个月,检测两组中层得治疗前后空腹及75克葡萄糖负荷后血糖、胰岛素、C肽、糖化血红蛋白(HbA1c)、胰岛β细胞功能指数(△I/△G)、胰岛素抵抗指数(HomaIR)等指标,比较两组患者血糖控制及胰岛β细胞功能恢复情况。结果BIAsp30和OHD具有降低血糖、改善胰岛β细胞功能的作用,治疗前后比较,差异有非常显著性(P<0.01);两组之间比较,BI-Asp30组在改善患者胰岛β细胞功能、降低胰岛素抵抗方面,明显优于OHD组(P<0.01),且血糖达标所需时间短于OHD组,差异有非常显著性(P<0.01)。结论对新诊断的2型糖尿病患者,早期给予每日两次注射BIAsp30强化治疗能更好的控制血糖,改善和恢复胰岛β细胞功能、降低胰岛素抵抗。     

Plasma relaxin concentration is related to beta-cell function and insulin sensitivity in women with type 2 diabetes mellitus

The aim of the study was to assess whether HbA_1c levels reflected mean blood glucose (MBG) levels in Type 2 diabetes. Despite the good correlation between HbA_1c and MBG, one-third of the patients had consistently higher HbA_1c or lower HbA_1c levels than that expected under the hypothesis that HbA_1c is solely determined by MBG, suggesting the existence of different haemoglobin glycation phenotypes. The use of HbA_1c alone for glycemic control monitoring in these patients could be insufficient to clearly trace their risk of complications.     

Associations of glucose control with insulin sensitivity and pancreatic beta-cell responsiveness in newly presenting type 2 diabetes.

We examined the ability of indices of insulin sensitivity and pancreatic beta-cell responsiveness to explain interindividual variability of clinical measures of glucose control in newly presenting type 2 diabetes. Subjects with newly presenting type 2 diabetes (n = 65; 53 males and 12 females; age, 54 +/- 1 yr; body mass index, 30.5 +/- 0.7 kg/m(2); mean +/- SE) underwent an insulin-modified iv glucose tolerance test to determine minimal model-derived insulin sensitivity (S(I)), glucose effectiveness, first-phase insulin secretion, and disposition index. Subjects also underwent a standard meal tolerance test (MTT) to measure fasting/basal (M(0)) and postprandial (M(I)) pancreatic beta-cell responsiveness. Stepwise linear regression used these indices to explain interindividual variability of fasting and postprandial plasma glucose and insulin concentrations and glycated hemoglobin (HbA(1C)). All measures of pancreatic beta-cell responsiveness (M(0), M(I), and first-phase insulin secretion) were negatively correlated with fasting plasma glucose (P < 0.01) and positively correlated with fasting plasma insulin (FPI) and insulin responses to MTT (P < 0.05). S(I) demonstrated negative correlation with FPI (P < 0.001) but failed to correlate with any glucose variable. M(I) followed by disposition index (composite index of insulin sensitivity and pancreatic beta-cell responsiveness) were most informative in explaining interindividual variability. It was possible to explain 70-80% interindividual variability of fasting plasma glucose, FPI, HbA(1C), and insulin responses to MTT, and only 25-40% interindividual variability of postprandial glucose. In conclusion, postprandial insulin deficiency is the most powerful explanatory factor of deteriorating glucose control in newly presenting type 2 diabetes. Indices of insulin sensitivity and pancreatic beta-cell responsiveness explain fasting glucose and HbA(1C) well but fail to explain postprandial glucose.     

罗格列酮对2型糖尿病大鼠胰岛β细胞的影响

目的小剂量链脲佐菌素注射加高脂饮食诱导的2型糖尿病大鼠罗格列酮治疗8周,胰岛β细胞形态学及功能等明显改善,说明罗格列酮不仅改善胰岛素抵抗,也保护了胰岛β细胞功能。     

Insulin resistance causes increased beta-cell mass but defective glucose-stimulated insulin secretion in a murine model of type 2 diabetes

Aims/hypothesis Although insulin resistance induces compensatory increases in beta cell mass and function to maintain normoglycaemia, it is not clear whether insulin resistance can precipitate beta cell dysfunction and hyperglycaemia without a pre-existing beta cell susceptibility. We therefore examined the beta cell phenotype in the MKR mouse, a model in which expression of a dominant-negative IGF 1 receptor (IGF1R) in skeletal muscle leads to systemic insulin resistance and diabetes. Materials and methods Circulating glucose, insulin and glucagon concentrations were measured. Insulin sensitivity, glucose tolerance and insulin release in vivo were assessed by i.p. insulin and glucose tolerance tests. Beta cell function was assessed via insulin secretion from isolated islets and the glucose gradient in the perfused pancreas. Beta cell morphology was examined via immunohistochemistry. MKR mice were fed a high-fat diet containing sucrose (HFSD) to test metabolic capacity and beta cell function. Results Insulin-resistant MKR mice developed hyperglycaemia and a loss of insulin responsiveness in vivo. Basal insulin secretion from the perfused pancreas was elevated, with no response to glucose. Despite the demand on insulin secretion, MKR mice had increased pancreatic insulin content and beta cell mass mediated through hyperplasia and hypertrophy. The HFSD worsened hyperglycaemia in MKR mice but, despite increased food intake in these mice, failed to induce the obesity observed in wild-type mice. Conclusions/interpretation Our studies demonstrate that insulin resistance of sufficient severity can impair glucose-stimulated insulin secretion, thereby undermining beta cell compensation and leading to hyperglycaemia. Moreover, because insulin stores were intact, the secretory defects reflect an early stage of beta cell dysfunction. Electronic supplementary material Electronic supplementary material is available for this article at Asghar and Chan contributed equally to this work. An erratum to this article can be found at     

Effects of insulin glargine versus metformin on glycemic variability, microvascular and beta-cell function in early type 2 diabetes

We investigated whether basal insulin as first-line treatment in recently diagnosed type 2 diabetes (T2D) can improve glucose control, microvascular function and preserve insulin secretion in comparison with metformin (MET). In this open-label, randomized, prospective 36-week study, 75 patients (44 m, 31 f, mean age 60.7 ± 9.2 year) were allocated to treatment with either MET 1,000 mg b.i.d. (n = 36) or insulin glargine (GLA) at bedtime (n = 39). At baseline and study end, we performed a continuous glucose monitoring for assessment of interstitial glucose (IG) and measured microvascular function using Laser-Doppler fluxmetry. GLA versus MET treatment resulted in a more pronounced reduction in FPG (Δ: 3.1 ± 2.5 vs. 1.4 ± 1.5 mmol/l; p < 0.001) and overall IG (Δ AUC. 671 ± 507 vs. 416 ± 537 mmol/l min; p = 0.04). Postprandial PG and IG differences after a standardized test meal did not reach significance. Proinsulin/C-peptide and HOMA B as marker of endogenous insulin secretion were significantly more improved by GLA. Microvascular blood flow improved only in MET-treated patients. Early basal insulin treatment with GLA in T2D patients provided a better control of FPG, overall IG load and biomarker of beta-cell function compared to the standard treatment with MET. MET treatment resulted in an improvement of microvascular function. Studies of longer duration are needed to evaluate the durability of glucose control and β cell protection with early GLA treatment.     

Basal insulin treatment in type 2 diabetes

Insulin glargine is the first 24-h recombinant DNA insulin analog introduced to the market. Substitution of glycine for asparagine and addition of two arginine residues raise the isoelectric point of insulin glargine and result in microprecipitates, delaying absorption from subcutaneous tissue. This delayed absorption result in fairly flat 24-h insulin concentration profiles with no discernible peak. Large, multicenter, randomized, controlled trials in patients with type 2 diabetes show that although NPH insulin and insulin glargine are equally effective in lowering glycosylated hemoglobin (A1c) and fasting blood glucose, there is a clear advantage of insulin glargine over NPH insulin in reducing nocturnal and overall hypoglycemia. Lower risk of hypoglycemia with glargine was also consistently demonstrated by trials comparing insulin glargine and premixed analog insulins. These studies also showed greater reduction in A1c with twice-daily premixed insulins compared with glargine, when insulin glargine was administered without mealtime insulin coverage. Insulin glargine was also compared with another insulin analog, insulin detemir. Trials showed that both insulin analogs are equally effective in lowering A1c and have comparable risk of hypoglycemia. Trials comparing insulin glargine with glucagon-like peptide-1 agonists showed comparable significant reductions in A1c with both regimens. Insulin glargine is well tolerated, has low immunogenicity, reduced risks for acute myocardial infarction, and a lower risk of hypoglycemia compared with NPH insulin in individuals with type 2 diabetes.     

短期诺和锐强化治疗对初诊2型糖尿病患者胰岛β细胞功能的影响

目的　探讨短期诺和锐强化治疗对初诊2型糖尿病(T2DM)患者胰岛β细胞功能和血糖控制的影响。　方法　对45例初诊T2DM患者进行为期两周的诺和锐强化治疗,分析比较治疗前后空腹(FPG)及餐后2 h血糖(2 hPG)、糖化血红蛋白(HbA1c)、静脉葡萄糖耐量试验时第一时相胰岛素及C肽分泌和胰岛素及C肽曲线下面积、胰岛素抵抗指数、胰岛素分泌指数、胰岛素敏感指数、空腹胰岛素(FIns)与FPG比值。　结果　诺和锐强化治疗后,FPG、2 hPG、HbA1c均较治疗前明显下降(P<0.01);空腹及第一时相胰岛素和C肽的分泌、胰岛素和C肽曲线下面积、FIns与FPG比值、胰岛素分泌指数、胰岛素敏感指数均较治疗前明显升高(P<0.01)。胰岛素抵抗指数较治疗前明显下降(P<0.01)。　结论　短期诺和锐强化治疗可显著改善初诊T2DM患者胰岛β细胞功能。     

罗格列酮治疗2型糖尿病的疗效分析

目的:观察罗格列酮(商品名文迪雅)对胰岛素抵抗的2型糖尿病患者的降糖疗效。方法:160例2型糖尿病曾应用胰岛素、其它类型降糖药或加强运动等基础治疗而血糖控制不理想的患者,加用罗格列酮4mg,每日1次;共观察24周,治疗前、后进行空腹、餐后2小时血糖及糖化血红蛋白测定。结果:罗格列酮治疗后患者空腹、餐后2小时血糖及糖化血红蛋白均有明显下降(P<0.01)。结论:罗格列酮能有效长期地控制血糖。