Importance of early insulin secretion: comparison of nateglinide and glyburide in previously diet-treated patients with type 2 diabetes

Monitoring and management of hyperglycemia in patients with advanced diabetic kidney disease

Diabetes mellitus is the leading cause of end-stage renal disease, and uncontrolled hyperglycemia is directly related to the increased mortality in this setting. As kidney function decreases, it becomes more challenging to control blood glucose since the risk of hypoglycemia increases. Decreased appetite, changes in glycaemia homeostasis, along with reduced renal excretion of anti-hyperglycemic drugs tend to facilitate the occurrence of hypoglycemia, despite the paradoxical occurrence of insulin resistance in advanced kidney disease. Thus, in patients using insulin and/or oral anti-hyperglycemic agents, dynamic adjustments with drug dose reduction or drug switching are often necessary. Furthermore, in addition to consider these pharmacokinetics alterations, it is of utmost importance to choose drugs with proven cardio-renal benefits in this setting, such as sodium-glucose co-transporter 2 inhibitors and glucagon-like peptide 1 receptor agonists. In this review, we summarize the indications and contraindications, titration of doses and side effects of the available anti-hyperglycemic agents in the presence of advanced diabetic kidney disease (DKD) and dialysis, highlighting the risks and benefits of the different agents. Additionally, basic renal function assessment and monitoring of glycemic control in DKD will be evaluated in order to guide the use of drugs and define the glycemic targets to be achieved.

Electrogenetic cellular insulin release for real-time glycemic control in type 1 diabetic mice

Sophisticated devices for remote-controlled medical interventions require an electrogenetic interface that uses digital electronic input to directly program cellular behavior. We present a cofactor-free bioelectronic interface that directly links wireless-powered electrical stimulation of human cells to either synthetic promoter–driven transgene expression or rapid secretion of constitutively expressed protein therapeutics from vesicular stores. Electrogenetic control was achieved by coupling ectopic expression of the L-type voltage-gated channel CaV1.2 and the inwardly rectifying potassium channel Kir2.1 to the desired output through endogenous calcium signaling. Focusing on type 1 diabetes, we engineered electrosensitive human β cells (Electroβ cells). Wireless electrical stimulation of Electroβ cells inside a custom-built bioelectronic device provided real-time control of vesicular insulin release; insulin levels peaked within 10 minutes. When subcutaneously implanted, this electrotriggered vesicular release system restored normoglycemia in type 1 diabetic mice.

Sulfonylurea derivatives and cancer, friend or foe?

Type 2 diabetes mellitus (T2DM) is associated with a higher risk of cancer and cancer-related mortality. Increased blood glucose and insulin levels in T2DM patients may be, at least in part, responsible for this effect. Indeed, lowering glucose and/or insulin levels pharmacologically appears to reduce cancer risk and progression, as has been demonstrated for the biguanide metformin in observational studies. Studies investigating the influence of sulfonylurea derivatives (SUs) on cancer risk have provided conflicting results, partly due to comparisons with metformin. Furthermore, little attention has been paid to within-class differences in systemic and off-target effects of the SUs. The aim of this systematic review is to discuss the available preclinical and clinical evidence on how the different SUs influence cancer development and risk. Databases including PubMed, Cochrane, Database of Abstracts on Reviews and Effectiveness, and trial registries were systematically searched for available clinical and preclinical evidence on within-class differences of SUs and cancer risk. The overall preclinical and clinical evidence suggest that the influence of SUs on cancer risk in T2DM patients differs between the various SUs. Potential mechanisms include differing affinities for the sulfonylurea receptors and thus differential systemic insulin exposure and off-target anti-cancer effects mediated for example through potassium transporters and drug export pumps. Preclinical evidence supports potential anti-cancer effects of SUs, which are of interest for further studies and potentially repurposing of SUs. At this time, the evidence on differences in cancer risk between SUs is not strong enough to guide clinical decision making.

Once-weekly dulaglutide 1.5 mg restores insulin secretion in response to intravenous glucose infusion

AIMS

To evaluate the effects of dulaglutide 1.5 mg on first- and second-phase insulin secretion in response to an intravenous (i.v.) glucose bolus challenge, in subjects with type 2 diabetes mellitus (T2DM; primary objective) and in healthy subjects.

MATERIALS AND METHODS

In this randomized, double-blind, placebo-controlled, 2-period crossover study, subjects received a single subcutaneous injection of dulaglutide 1.5 mg or placebo on day 1 of each period. On day 3, subjects underwent a 6-hour insulin infusion, followed by an i.v. glucose bolus and a glucagon challenge during hyperglycaemia. Areas under the concentration-time curve and maximum concentrations for first- (AUC_0-10 and C_max0-10 ) and second-phase secretion (AUC_10-180 and C_max10-180 ) were calculated for insulin and C-peptide. The glucose disappearance constant (K_g ) and homeostasis model assessment of β-cell function (HOMA-β) were assessed.

RESULTS

In 20 subjects with T2DM, dulaglutide increased mean insulin AUC_0-10 by 7.92-fold and C_max0-10 by 5.40-fold vs placebo, and mean AUC_10-180 and C_max10-180 by 2.44- and 3.78- fold, respectively. In 10 healthy subjects, dulaglutide increased the mean insulin AUC_0-10 by 3.09-fold and C_max0-10 by 2.96-fold vs placebo, and mean AUC_10-180 and C_max10-180 by 2.04- and 4.15-fold, respectively. The corresponding C-peptide values also increased. Mean K_g and HOMA-β were higher after dulaglutide compared with placebo.

CONCLUSIONS

In subjects with T2DM, a single dulaglutide 1.5-mg dose restored the first-phase insulin secretion in response to an i.v. glucose bolus, increased the second-phase insulin response and enhanced β-cell function.

Rationale for treatment options for mealtime glucose control in patients with type 2 diabetes

While glycemic control is routinely assessed using HbA1c and fasting glucose measures, postprandial glucose (PPG) is also an important contributor of overall glycemia. Furthermore, PPG excursions have been linked to complications of diabetes. This review examines the effects of glucose-lowering therapies (including treatments administered at mealtime) on postprandial hyperglycemia in patients with type 2 diabetes. A PubMed search was conducted to identify clinical studies of treatments for mealtime glucose control in type 2 diabetes. Different treatments may have comparable effects on HbA1c but varying effects on PPG control and glucose fluctuations. Older classes of oral glucose-lowering treatments administered at mealtime to lower PPG include meglitinides and α-glucosidase inhibitors. Injectable therapies, including prandial insulin analogs, glucagon-like peptide-1 receptor agonists (GLP-1RAs), and the amylin analog pramlintide, all effectively target postprandial hyperglycemia. Compared with longer-acting GLP-1RAs, short-acting GLP-1RAs, such as exenatide twice daily and lixisenatide once daily, have a greater effect on PPG control, which is primarily mediated by a more pronounced effect on delayed gastric emptying. Dipeptidyl peptidase-4 inhibitors and sodium-glucose cotransporter 2 inhibitors also reduce postprandial hyperglycemia. To achieve more physiologically normal glycemic control, choice of therapy should ideally aim to address daily glucose fluctuations, including hyperglycemic peaks and hypoglycemic troughs, and long-term glycemic control.

A stable isotope method for in vivo assessment of human insulin synthesis and secretion

AIMS

In vitro, beta cells immediately secrete stored but readily releasable insulin in response to a rise of glucose. During a prolonged insulin response, this is followed by newly synthesized insulin. Our aim was to develop an in vivo test to determine the ratio between readily available and newly synthesized insulin after a stimulus in humans by labelling newly synthesized insulin.

METHODS

A stable isotope tracer of 1.0 g ¹³C leucine with C-peptide as target peptide was administered 45 min prior to 75 g glucose load of a frequently blood sampled 210-min oral glucose tolerance test (OGTT). Our OGTT also encompassed collection of urine, which has a high content of C-peptide. Prior, the optimal conditions under which the tracer ¹³C leucine was administered for enrichment of (pre) proinsulin were established. Also, techniques to obtain urinary C-peptide under highly purified circumstances were set up. Our main outcome measure was the stable isotope enrichment of de novo C-peptide, which we related to early plasma insulin and glucose AUC. Twelve healthy Caucasian individuals (M4F8, age 41.8 ± 2.3, BMI 28.3 ± 1.7) with normal glucose tolerance underwent our OGTT.

RESULTS

We found that during a 75-g OGTT, newly synthesized insulin contributed approximately 20 % of total insulin secretion. The pattern of isotope enrichment obtained by collecting multiple urine voids was suggestive that the newly synthesized insulin contributes to the late phase of insulin secretion. De novo C-peptide correlated negatively with both early plasma insulin AUC (r = -0.629, P = 0.028) and early plasma glucose AUC (r = -0.605, P = 0.037).

CONCLUSIONS

With stable isotope technique added to OGTT, we were able to measure newly synthesized insulin in healthy individuals. This new technique holds the promise that it is feasible to develop a direct in vivo beta cell function test.

Effect of nateglinide and glimepiride in reducing postprandial hyperglycaemia in patients with type 2 diabetes mellitus

Aim — The purpose of this study was to compare the effect of nateglinide on two-hour post-meal glucose levels with that of glimepiride in patients with type 2 diabetes mellitus. Methods — Glucose and insulin levels were measured during 14-hour profiles (comprising three meal challenges) and intravenous glucose tolerance tests performed before and after five-weeks of treatment with nateglinide (120 mg, a.c.) or glimepiride (1 mg, o.d.) in a randomised, two-centre, double-blind, crossover study in 26 patients with type 2 diabetes and fasting initial glucose levels < 13.9 mmol/L. Results — Mean two-hour postprandial glucose levels were significantly lower during nateglinide treatment than during glimepiride treatment (9.46 vs. 10.00 mmol/L, respectively; p<0.05). The 14-hour incremental glucose area under the curve was -2.2 mmol•h/L during nateglinide treatment and +6.2 mmol•h/L during glimepiride treatment (p<0.01). Nateglinide improved both the early insulin response during meals and the acute insulin response during intravenous glucose tolerance tests, restoring the biphasic insulin secretion pattern. Both insulin secretagogues improved intravenous glucose tolerance relative to the pre-treatment period, but only nateglinide restored a biphasic insulin profile. Conclusions — By restoring a more physiological post-load insulin response, nateglinide is more effective than glimepiride in controlling postprandial glucose excursions.

Comparison of the postprandial glucose and insulin profiles with nateglinide and gliclazide in type 2 diabetic patients

Aim

The aim of this study was to compare glucose, insulin and proinsulin profiles during nateglinide and gliclazide treatment over an extended postprandial period.

Materials and methods

This double-blind crossover trial was conducted in 23 type 2 diabetic patients (mean HbA1C 6.6%; range 6.0—7.4%) who received, for one week each, nateglinide 120 mg t.i.d., gliclazide 80 mg b.i.d. and placebo, with a one week wash out period between treatments.

Results

The 2-hour postprandial glucose concentration was markedly lower with nateglinide than with gliclazide (5.83 vs. 7.21 mmol/L; p<0.05), as was the post-meal peak glucose elevation (8.63 vs. 9.72 mmol/L; p=0.085), which was associated with earlier, higher and shorter-lived insulin and proinsulin secretory responses. However, 0—7-hour AUCs during standardised meal test for glucose and insulin between the two drugs did not statistically differ. No symptomatic hypoglycaemic events occurred during the 7-hour test period.

Conclusion

Nateglinide was more effective than gliclazide in controlling postprandial hyperglycaemia and showed a faster effect on insulin and proinsulin secretion.

WITHDRAWN: Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

The Cochrane Metabolic and Endocrine Disorders Group withdrew this review as of Issue 7, 2015 because of the involvement of one author (SS Lund) being employed in a pharmaceutical company. The authors of the review and the Cochrane Metabolic and Endocrine Disorders Group did not find that this was a breach of the rules of the Cochrane Collaboration at the time when it was published. However, after the publication of the review, the Cochrane Collaboration requested withdrawal of the review due to the employment of the author. A new protocol for a review to cover this topic will be published. This will have a new title and a markedly improved protocol fulfilling new and important developments and standards within the Cochrane Collaboration as well as an improved inclusion and search strategy making it necessary to embark on a completely new review project.

The editorial group responsible for this previously published document have withdrawn it from publication.

Effect of repaglinide, administered two or three times daily for 3 months, on glycaemic control in Japanese patients with type 2 diabetes mellitus

OBJECTIVES

To compare the efficacy, safety and compliance of repaglinide, administered either two or three times daily, regarding glycaemic control in patients with type 2 diabetes mellitus.

METHODS

Japanese adults with type 2 diabetes mellitus, who had been treated without sulphonylureas or glinides for >3 months, were randomly assigned to two groups to receive either 0.25 mg repaglinide, oral, twice daily (group A) or 0.25 mg repaglinide, oral, three times daily (group B). Glycosylated haemoglobin (HbA1c), glycoalbumin (GA) and 1,5-anhydroglucitol (1,5-AG) levels were measured at 0, 1, 2 and 3 months after treatment commenced.

RESULTS

Out of 43 patients who enrolled (group A, n = 22; group B, n = 21), 33 patients completed the trial (group A, n = 16; group B, n = 17). No significant between-group differences in HbA1c, GA, or 1,5-AG levels were seen at 1-3 months. No severe hypoglycaemic episodes or other adverse events were observed.

CONCLUSIONS

Minimal-dose repaglinide administered twice daily was similar in efficacy and safety to three-times-daily administration, in Japanese patients with type 2 diabetes mellitus. Administration of repaglinide twice daily could be an alternative regimen for patients who cannot take repaglinide three times daily.

Different antihyperglycaemic drug effects on glycaemic variability in Type 2 diabetic patients

Optimizing treatments for type 2 diabetes mellitus (T2DM) remains an urgent issue. In addition to T2DM treatment strategies, such as glycaemic goals (glucose and glycated haemoglobin ? HbА1c) among different patient populations, the influence of glycaemic variability (GV) on the prognosis of patients with T2DM is also important. According to recent data, GV is associated with cardiovascular complications arising from T2DM. However, although the influence of GV on the development of vascular complications arising from diabetes and underlying mechanisms has been extensively investigated, few studies have investigated the effects of different glucose-lowering medications on GV, and there are even fewer reviews of this topic. This type of analysis is highly relevant, particularly because new classes of antidiabetic medications with potent glucose-dependent insulinotropic effects have been developed. These include groups of drugs that mimic or enhance incretin activity, such as glucagon-like peptide (GLP)-1 analogues/mimetics and dipeptidyl peptidase (DPP)-4 inhibitors. A glucose-dependent mechanism suggests that these groups of antidiabetic medications have beneficial effects on GV. Thus, the current study focusses on the comparative analysis of drugs based on their incretin effects (GLP-1 analogues/mimetics and DPP-4 inhibitors) and оther antidiabetic medications with regard to GV in the patients with T2DM.

Effect of repaglinide versus glimepiride on daily blood glucose variability and changes in blood inflammatory and oxidative stress markers

BACKGROUND

Hemoglobin A1c is the main treatment target for patients with type 2 diabetes. It has also been shown recently that postprandial glucose and daily glucose fluctuations affect the progression of diabetic complications and atherosclerotic damages.

METHODS

Continuous glucose monitoring was performed in patients with type 2 diabetes to evaluate the efficacy of repaglinide vs. glimepiride on postprandial glucose spikes and fluctuations. A total of 10 Japanese patients with type 2 diabetes treated with glimepiride monotherapy were enrolled. After observation period for 8 weeks, glimepiride was changed to repaglinide. Continuous glucose monitoring was performed whilst consuming calorie-restricted diets for two days at baseline and at the end of the 12-week trial. Blood and urine samples were collected for measurement of glucose control parameters and inflammatory and oxidative stress markers on the last day of taking either glimepiride or repaglinide.

RESULTS

Nine patients completed the trial. Although the glucose control parameters were not significantly different between glimepiride and repaglinide, the mean amplitude of glycemic excursions measured by continuous glucose monitoring was significantly reduced by changing treatment from glimepiride to repaglinide. The levels of plasminogen activator inhibitor-1, high sensitivity C-reactive protein, and urinary 8-hydoroxydeoxyguanosine were reduced significantly by repaglinide treatment.

CONCLUSION

These results suggest that repaglinide may decrease the risk of cardiovascular disease in type 2 diabetes by minimizing glucose fluctuations thereby reducing inflammation and oxidative stress.

The glycemic/metabolic responses to meal tolerance tests at breakfast, lunch and dinner, and effects of the mitiglinide/voglibose fixed-dose combination on postprandial profiles in Japanese patients with type 2 diabetes mellitus

BACKGROUND

Meal tolerance tests (MTTs) are usually conducted at breakfast after overnight fasting in type 2 diabetes mellitus (T2DM) patients, but differences in postprandial glycemic responses between meals have been reported.

OBJECTIVE

We conducted MTTs at breakfast, lunch, and dinner to examine the effects of a fixed combination of 10 mg mitiglinide/0.2 mg voglibose (the combination) on glycemic/metabolic responses to meals during the day in T2DM patients. MTTs with unified meals were conducted in 11 T2DM patients before and after 4 weeks of treatment with the combination administered thrice daily before meals. Glycemic/metabolic profiles measured before and at 30, 60, and 120 min after each meal were compared between each meal and between the baseline and treatment periods.

RESULTS AND CONCLUSION

The combination significantly reduced postprandial hyperglycemia after each meal. Postprandial AUC0 - 120 min for insulin significantly decreased after lunch and dinner compared with after breakfast, while insulin levels significantly increased at only 30 min after breakfast and dinner. The combination also significantly increased postprandial C-peptide and active glucagon-like peptide-1 levels, and reduced free fatty acid and triglyceride levels, but did not significantly affect glucagon levels compared with baseline, confirming that treatment with the combination improves postprandial responses in Japanese T2DM patients.

Complications of diabetes therapy

Current strategies for the treatment of type 2 diabetes mellitus promote individualized plans to achieve target glucose levels on a patient-by-patient basis while minimizing treatment related risks. Maintaining glycemic control over time is a significant challenge because of the progressive nature of diabetes as a result of declining β-cell function. This article identifies complications of non-insulin treatments for diabetes. The major classes of medications are reviewed with special focus on target population, mechanism of action, effect on weight, cardiovascular outcomes and additional class-specific side effects including effects on bone. Effects on β-cell function are also highlighted.

Efficacy and safety of nateglinide plus vildagliptin combination therapy compared with switching to vildagliptin in type 2 diabetes patients inadequately controlled with nateglinide

Aims/Introduction

To investigate the efficacy and safety of vildagliptin, a potent dipeptidyl peptidase‐4 inhibitor, as add‐on to nateglinide, compared with switching to vildagliptin in Japanese type 2 diabetes patients poorly controlled with nateglinide.

Materials and Methods

A total of 40 patients inadequately controlled with nateglinide were randomized to the switching group (n = 20, switching from nateglinide to vildagliptin) or combination group (n = 20, nateglinide plus vildagliptin). A meal tolerance test was carried out at weeks 0 and 24.

Results

The mean changes in glycated hemoglobin from baseline to week 24 were −1.2 ± 0.3% and −0.3 ± 0.5% in patients of the combination and switching groups, respectively, and the difference between the groups was statistically significant (P < 0.001). The mean changes in area under the curve of glucose from 0 to 180 min (AUC_0–180 min) from baseline to week 24 was −361 ± 271.3 mmol·min/L in patients of the combination group compared with 141 ± 241.9 mmol·min/L in those of the switching group (P < 0.001). The incidence of hypoglycemic events was low (three in the combination group), and none of the patients developed severe hypoglycemia. Although the addition of vildagliptin to nateglinide did not significantly increase insulin secretion relative to glucose elevation (ISG) after meal load (ISG_0–180 min: AUC_0–180 min insulin / AUC_0–180 min glucose) in comparison with that in baseline, the mean ISG_0–30 min 24 weeks after addition of vildagliptin to nateglinide was significantly higher than that at baseline. In contrast, switching from nateglinide to vildagliptin reduced the mean ISG_0–180 min, relative to baseline.

Conclusions

The combination therapy of vildagliptin and nateglinide is effective and safe in Japanese type 2 diabetes, and the improved glycemic control is as a result of augmentation of nateglinide‐induced early phase insulin secretion. This trial was registered with UMIN (no. ID000004010).

The role of nateglinide and repaglinide, derivatives of meglitinide, in the treatment of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases worldwide, presenting a great challenge to the public health systems due to high morbidity and mortality, because of frequent micro-/macro-vascular complications. Many treatment options are now available, with different efficacy as well as mechanisms of action to improve deranged glucose metabolism. We review some of the available data on derivatives of meglitinide, namely nateglinide and repaglinide. These two compounds increase insulin secretion by a mechanism similar to the one of sulfonylureas, but with a shorter half-life. Nateglinide and repaglinide, derivatives of meglitinides, have characteristic pharmacodynamic and pharmacokinetic properties that, together with their proposed mechanism of action, make them useful for type 2 diabetes mellitus, especially when used in combination therapy.

Effects of nateglinide and acarbose on glycemic excursions in standardized carbohydrate and mixed-meal tests in drug-naïve type 2 diabetic patients

The aim of this study was to compare the effects of nateglinide and acarbose on glycemic excursions and postprandial glucose profiles with different types of meals (standardized carbohydrate and mixed meals) in drug-naïve type 2 diabetic patients. A randomized, parallel-group prospective design clinical trial was conducted and a total of 39 drug-naïve patients (16 males and 23 females, aged 56.7±10.2 years) were enrolled. The patients were randomly divided into group A [nateglinide 120 mg three times daily (t.i.d.), n=19] and group B (acarbose 50 mg t.i.d., n=20). The standardized carbohydrate and mixed-meal tests were performed at baseline and at the end of study. Continuous glucose monitoring system (CGMS) data were recorded. Various parameters that measure glucose variability were derived from the CGMS data. In the standardized carbohydrate meal tests, the postprandial glucose excursions (PPGEs) were significantly decreased in the two groups after 12 weeks of treatment (P<0.05), whereas the decrease was more prominent in the acarbose compared to the nateglinide group (P=0.138). In the mixed-meal tests, the mean sensor glucose values [24-h mean blood glucose (MBG)] were significantly decreased in the two groups after 12 weeks of treatment (P<0.05) and the parameters of glucose excursions, including standardized deviation (SD), largest amplitude of glycemic excursion (LAGE), mean of daily differences (MODD) and mean amplitude of glycemic excursion (MAGE), were reduced in the two groups. However, the decreases in SD and LAGE in the nateglinide group were statistically significant, whereas in the acarbose group only the decreases in LAGE were statistically significant. The efficiency of nateglinide or acarbose in lowering postprandial 120-min hyperglycemia were similar in the standardized carbohydrate meal test. However, acarbose was more efficient in lowering postprandial 30- and 60-min hyperglycemia (P<0.05) compared to nateglinide. The fasting and postprandial total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) had a tendency to decrease from the baseline after 12 weeks of treatment with nateglinide, whereas fasting and postprandial high-density lipoprotein cholesterol (HDL-C) had a tendency to increase. Acarbose did not affect the fasting or postprandial lipid profiles after 12 weeks of treatment (P>0.05). In conclusion, nateglinide and acarbose effectively improved postprandial glycemic control, although acarbose was shown to be more efficient in controlling early (30 and 60 min) postprandial glucose excursions in the carbohydrate meal test, whereas nateglinide was shown to be superior to acarbose in controlling postprandial glucose excursions in the mixed-meal test.

Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a growing health problem worldwide. Whether sulphonylureas show better, equal or worse therapeutic effects in comparison with other antidiabetic interventions for patients with T2DM remains controversial.

OBJECTIVES

To assess the effects of sulphonylurea monotherapy versus placebo, no intervention or other antidiabetic interventions for patients with T2DM.

SEARCH METHODS

We searched publications in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, LILACS and CINAHL (all until August 2011) to obtain trials fulfilling the inclusion criteria for our review.

SELECTION CRITERIA

We included clinical trials that randomised patients 18 years old or more with T2DM to sulphonylurea monotherapy with a duration of 24 weeks or more.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias. The primary outcomes were all-cause and cardiovascular mortality. Secondary outcomes were other patient-important outcomes and metabolic variables. Where possible, we used risk ratios (RR) with 95% confidence intervals (95% CI) to analyse the treatment effect of dichotomous outcomes. We used mean differences with 95% CI to analyse the treatment effect of continuous outcomes. We evaluated the risk of bias. We conducted trial sequential analyses to assess whether firm evidence could be established for a 10% relative risk reduction (RRR) between intervention groups.

MAIN RESULTS

We included 72 randomised controlled trials (RCTs) with 22,589 participants; 9707 participants randomised to sulphonylureas versus 12,805 participants randomised to control interventions. The duration of the interventions varied from 24 weeks to 10.7 years. We judged none of the included trials as low risk of bias for all bias domains. Patient-important outcomes were seldom reported.First-generation sulphonylureas (FGS) versus placebo or insulin did not show statistical significance for all-cause mortality (versus placebo: RR 1.46, 95% CI 0.87 to 2.45; P = 0.15; 2 trials; 553 participants; high risk of bias (HRB); versus insulin: RR 1.18, 95% CI 0.88 to 1.59; P = 0.26; 2 trials; 1944 participants; HRB). FGS versus placebo showed statistical significance for cardiovascular mortality in favour of placebo (RR 2.63, 95% CI 1.32 to 5.22; P = 0.006; 2 trials; 553 participants; HRB). FGS versus insulin did not show statistical significance for cardiovascular mortality (RR 1.36, 95% CI 0.68 to 2.71; P = 0.39; 2 trials; 1944 participants; HRB). FGS versus alpha-glucosidase inhibitors showed statistical significance in favour of FGS for adverse events (RR 0.63, 95% CI 0.52 to 0.76; P = 0.01; 2 trials; 246 participants; HRB) and for drop-outs due to adverse events (RR 0.28, 95% CI 0.12 to 0.67; P = 0.004; 2 trials; 246 participants; HRB).Second-generation sulphonylureas (SGS) versus metformin (RR 0.98, 95% CI 0.61 to 1.58; P = 0.68; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 0.92, 95% CI 0.60 to 1.41; P = 0.70; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.79 to 1.18; P = 0.72; 4 trials; 1642 participants; HRB), meglitinides (RR 1.44, 95% CI 0.47 to 4.42; P = 0.52; 7 trials; 2038 participants; HRB), or incretin-based interventions (RR 1.39, 95% CI 0.52 to 3.68; P = 0.51; 2 trials; 1503 participants; HRB) showed no statistically significant effects regarding all-cause mortality in a random-effects model. SGS versus metformin (RR 1.47; 95% CI 0.54 to 4.01; P = 0.45; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 1.30, 95% CI 0.55 to 3.07; P = 0.55; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.73 to 1.28; P = 0.80; 4 trials; 1642 participants; HRB) or meglitinide (RR 0.97, 95% CI 0.27 to 3.53; P = 0.97; 7 trials, 2038 participants, HRB) showed no statistically significant effects regarding cardiovascular mortality. Mortality data for the SGS versus placebo were sparse. SGS versus thiazolidinediones and meglitinides did not show statistically significant differences for a composite of non-fatal macrovascular outcomes. SGS versus metformin showed statistical significance in favour of SGS for a composite of non-fatal macrovascular outcomes (RR 0.67, 95% CI 0.48 to 0.93; P = 0.02; 3018 participants; 3 trials; HRB). The definition of non-fatal macrovascular outcomes varied among the trials. SGS versus metformin, thiazolidinediones and meglitinides showed no statistical significance for non-fatal myocardial infarction. No meta-analyses could be performed for microvascular outcomes. SGS versus placebo, metformin, thiazolidinediones, alpha-glucosidase inhibitors or meglitinides showed no statistical significance for adverse events. SGS versus alpha-glucosidase inhibitors showed statistical significance in favour of SGS for drop-outs due to adverse events (RR 0.48, 95% CI 0.24 to 0.96; P = 0.04; 9 trials; 870 participants; HRB). SGS versus meglitinides showed no statistical significance for the risk of severe hypoglycaemia. SGS versus metformin and thiazolidinediones showed statistical significance in favour of metformin (RR 5.64, 95% CI 1.22 to 26.00; P = 0.03; 4 trials; 3637 participants; HRB) and thiazolidinediones (RR 6.11, 95% CI 1.57 to 23.79; P = 0.009; 6 trials; 5660 participants; HRB) for severe hypoglycaemia.Third-generation sulphonylureas (TGS) could not be included in any meta-analysis of all-cause mortality, cardiovascular mortality or non-fatal macro- or microvascular outcomes. TGS versus thiazolidinediones showed statistical significance regarding adverse events in favour of TGS (RR 0.88, 95% CI 0.78 to 0.99; P = 0.03; 3 trials; 510 participants; HRB). TGS versus thiazolidinediones did not show any statistical significance for drop-outs due to adverse events. TGS versus other comparators could not be performed due to lack of data.For the comparison of SGS versus FGS no meta-analyses of all-cause mortality, cardiovascular mortality, non-fatal macro- or microvascular outcomes, or adverse events could be performed.Health-related quality of life and costs of intervention could not be meta-analysed due to lack of data.In trial sequential analysis, none of the analyses of mortality outcomes, vascular outcomes or severe hypoglycaemia met the criteria for firm evidence of a RRR of 10% between interventions.

AUTHORS' CONCLUSIONS

There is insufficient evidence from RCTs to support the decision as to whether to initiate sulphonylurea monotherapy. Data on patient-important outcomes are lacking. Therefore, large-scale and long-term randomised clinical trials with low risk of bias, focusing on patient-important outcomes are required.

Nateglinide provides tighter glycaemic control than glyburide in patients with Type 2 diabetes with prevalent postprandial hyperglycaemia

AIMS

Postprandial hyperglycaemia in patients with Type 2 diabetes mellitus has been linked to the development of cardiovascular disease. This study compared the effects of mealtime (thrice-daily) nateglinide with once-daily glyburide on postprandial glucose levels in patients with Type 2 diabetes and postprandial hyperglycaemia.

METHODS

Patients with Type 2 diabetes aged ≥ 21 years with 2-h postprandial glucose levels ≥ 11.1 mmol/l, HbA(1c) of 6.5-8.5% (48-69 mmol/mol) and BMI of 22-30 kg/m(2) were randomized to 6 weeks' double-blind treatment with nateglinide 120 mg three times daily prior to meals, or glyburide 5 mg once daily before breakfast. The primary endpoint was the baseline-adjusted change in plasma glucose from preprandial (fasting plasma glucose) to 2-h postprandial glucose levels (2-h postprandial glucose excursion) at 6 weeks.

RESULTS

Patients were randomized to nateglinide (n = 122) or glyburide (n = 110). The treatment groups were similar in terms of age, gender, BMI, fasting plasma glucose, 2-h postprandial glucose and HbA(1c). At endpoint, nateglinide recipients had significantly greater reductions than those receiving glyburide in both the 2-h (-2.4 vs. -1.6 mmol/l; P = 0.02) and 1-h (-1.7 vs. -0.9 mmol/l; P = 0.016) postprandial glucose excursions. Adverse events, most commonly symptomatic hypoglycaemia, were reported in 26% of recipients of glyburide and 22% of recipients of nateglinide. Episodes of suspected mild hypoglycaemia were reported in 24% of recipients of glyburide and 10% of recipients of nateglinide.

CONCLUSIONS

Nateglinide leads to greater reductions in postprandial glucose excursions and is associated with a lower risk of hypoglycaemia than glyburide in this selected population of patients with Type 2 diabetes.

Drug-induced hypoglycaemia: an update

Drugs are the most frequent cause of hypoglycaemia in adults. Although hypoglycaemia is a well known adverse effect of antidiabetic agents, it may occasionally develop in the course of treatment with drugs used in everyday clinical practice, including NSAIDs, analgesics, antibacterials, antimalarials, antiarrhythmics, antidepressants and other miscellaneous agents. They induce hypoglycaemia by stimulating insulin release, reducing insulin clearance or interfering with glucose metabolism. Several drugs may also potentiate the hypoglycaemic effect of antidiabetic agents. Administration of these agents to individuals with diabetes mellitus is of most concern. Many of these drugs, and depending on clinical setting, may also induce hyperglycaemia. Drug-induced hepatotoxicity and nephrotoxicity may lead in certain circumstances to hypoglycaemia. Some drugs may also induce hypoglycaemia by causing pancreatitis. Drug-induced hypoglycaemia is usually mild but may be severe. Effective clinical management can be handled through awareness of this drug-induced adverse effect on blood glucose levels. Herein, we review pertinent clinical information on the incidence of drug-induced hypoglycaemia and discuss the underlying pathophysiological mechanisms, and prevention and management.

Clinical evidence and mechanistic basis for vildagliptin's action when added to metformin

Several new oral antidiabetic agents, known as 'gliptins' or 'enzyme dipeptidyl peptidase-IV (DPP-4) inhibitors', have been developed for the treatment of type 2 diabetes and a key clinical use of the gliptins is in combination with metformin. There are important differences in the kinetics of the interaction of different gliptins with the catalytic site of DPP-4, which may lead to varying pharmacokinetics, pharmacodynamics and dosing regimens. Therefore, individual gliptins need to be characterized and here we discuss the extensively studied DPP-4 inhibitor vildagliptin, which has binding characteristics that ensure inhibition of the enzyme beyond the presence of detectable drug levels in plasma. As vildagliptin has been used most often at doses of 50 mg once or twice daily, in combination with metformin, this review focuses on these dose regimens. All clinical trials employing vildagliptin (50 mg once or twice daily) as an add-on therapy to metformin (identified by MEDLINE search using keywords vildagliptin and metformin or known by authors to be in press) are reviewed, as is current knowledge of the mechanism of action of vildagliptin. Vildagliptin added to a stable dose of metformin elicits a dose-related decrease in both HbA1c and fasting plasma glucose. The additional efficacy seen with 50 mg twice daily [ΔHbA1c ∼- 1.1% (-12.1 mmol/mol)] relative to 50 mg once daily [ΔHbA1c ∼- 0.7% (-7.7 mmol/mol)] is attributable to an overnight effect of the evening dose of vildagliptin, with prolonged DPP-4 inhibition and elevated fasting levels of the intact and insulinotropic form of glucagon-like peptide-1 (GLP-1). Vildagliptin's therapeutic actions are primarily mediated by GLP-1 and metformin enhances vildagliptin's effect to raise plasma levels of intact GLP-1. Vildagliptin is weight-neutral and has a very low hypoglycaemic potential, explained by its remarkable ability to enhance both α-cell and β-cell sensitivity to glucose. Therefore, vildagliptin offers a clinically important outcome when added to metformin with a twice daily dose regimen, taking advantage of its tight binding and slow dissociation characteristics that lead to a sustained overnight effect.

An cell-assembly derived physiological 3D model of the metabolic syndrome, based on adipose-derived stromal cells and a gelatin/alginate/fibrinogen matrix

One of the major obstacles in drug discovery is the lack of in vitro three-dimensional (3D) models that can capture more complex features of a disease.Here we established a in vitro physiological model of the metabolic syndrome (MS) using cell-assembly technique (CAT), which can assemble cells into designated places to form complex 3D structures. Adipose-derived stromal (ADS) cells were assembled with gelatin/alginate/fibrinogen. Fibrin was employed as an effective material to regulate ADS cell differentiation and self-organization along with other methods. ADS cells differentiated into adipocytes and endothelial cells, meanwhile, the cells were induced to self-organize into an analogous tissue structure. Pancreatic islets were then deposited at designated locations and constituted the adipoinsular axis with adipocytes. Analysis of the factors involved in energy metabolism showed that this system could capture more pathological features of MS. Drugs known to have effects on MS showed accordant effects in this system, indicating that the model has potential in MS drug discovery. Overall, this study demonstrated that cell differentiation and self-organization can be regulated by techniques combined with CAT. The model presented could result in a better understanding of the pathogenesis of MS and the development of new technologies for drug discovery.

Nateglinide combination therapy with basal insulin and metformin in patients with Type 2 diabetes

AIMS

To compare the effect of adding nateglinide or placebo on postprandial glucose excursions (PPGEs), glycated haemoglobin (HbA(1c)), diurnal glucose profiles and hypoglycaemia in patients with Type 2 diabetes treated with the combination of basal insulin and metformin.

RESEARCH DESIGN AND METHODS

This was an investigator-initiated, double-blind, randomized, parallel-group, study in five centres. Patients with Type 2 diabetes (n = 88, age 56.0 +/- 0.9 years, duration of diabetes 9.4 +/- 0.5 years, HbA(1c) 7.8 +/- 0.1%, body mass index 32.4 +/- 0.5 kg/m(2)) treated with basal insulin and metformin entered a 24-week period, during which basal insulin was titrated to optimize glucose control. Thereafter, the patients were randomized to receive either nateglinide (120 mg three times daily) or placebo before their main meals for 24 weeks.

RESULTS

During the optimization period, HbA(1c) decreased by -0.3 +/- 0.1 and -0.4 +/- 0.2% (NS) and insulin doses increased by 10.0 IU (2.0-32.0) [0.09 IU/kg (0.02-0.34)] and 10.0 IU (0.0-19.0) [0.11 IU/kg (0.0-0.25)] (NS) in the nateglinide and placebo groups. Mean postprandial glucose during weeks 20-24 averaged 9.0 +/- 0.3 and 10.0 +/- 0.3 mmol/l in the nateglinide and placebo groups (P = 0.025) and mean PPGE averaged 2.4 +/- 0.2 and 3.1 +/- 0.2 mmol/l, respectively (P = 0.019). At 24 weeks as compared with 0 weeks, mean HbA(1c) had decreased by 0.41 +/- 0.12% in the nateglinide group and by 0.04 +/- 0.12% in the placebo group (P = 0.023). The frequency of confirmed, symptomatic hypoglycaemia was 7.7 episodes/patient-year vs. 4.7 episodes/patient-year in the nateglinide and placebo groups (P = 0.031).

CONCLUSIONS

Addition of a short-acting insulin secretagogue at main meals improves postprandial hyperglycaemia during combination therapy with basal insulin and metformin, but increases the frequency of hypolycaemia.

Oral combination therapy: repaglinide plus metformin for treatment of type 2 diabetes

Type 2 diabetes is characterized by decreases in insulin secretion and insulin sensitivity. Several classes of oral antidiabetic medications are currently approved for the treatment of type 2 diabetes. A stepwise treatment approach from monotherapy to combination therapy is traditionally used; however, the frequency of treatment failure with monotherapy has resulted in a move towards earlier treatment with combination therapies that target the two principal defects in glycaemic control. One such combination regimen is repaglinide (a prandial glucose regulator that increases insulin release) plus metformin (an insulin sensitizer that inhibits hepatic glucose output, increases peripheral glucose uptake and utilization and minimizes weight gain). Findings from several clinical trials have shown that combination therapy with repaglinide plus metformin is well tolerated and results in greater reductions of haemoglobin A(1c) and fasting plasma glucose values compared with either monotherapy. Repaglinide may also provide a more suitable alternative to combination therapy with sulphonylureas and metformin because of its reduced propensity for hypoglycaemia. The combination regimen of repaglinide plus metformin should therefore be considered as a valuable option in the management of patients with type 2 diabetes when monotherapy is no longer adequate.

Nateglinide, alone or in combination with metformin, is effective and well tolerated in treatment-naïve elderly patients with type 2 diabetes

AIM

The aim of this work was to assess the efficacy and tolerability of nateglinide alone or in combination with metformin in elderly patients with type 2 diabetes (T2DM).

METHODS

Study 1 was a 12-week, multicentre, randomized, double blind and placebo-controlled study of nateglinide monotherapy (120 mg, before meals) in 66 drug-naïve patients with T2DM aged >or=65 years. Study 2 was a 104-week, multicentre, randomized, double blind and active-controlled study of nateglinide (120 mg, before meals) or glyburide (up to 5 mg bid) in combination with metformin (up to 1000 mg bid) in 69 treatment-naïve patients with T2DM aged >or=65 years. HbA(1c), fasting and postprandial glucose levels, and safety assessments were made.

RESULTS

In Study 1, nateglinide significantly reduced HbA(1c) from baseline (7.6 +/- 0.1% to 6.9 +/- 0.1%; Delta = -0.7 +/- 0.1%, p < 0.001) and compared with placebo (between-group difference = -0.5%, p = 0.004 vs. nateglinide). No hypoglycaemia was reported. In Study 2, combination therapy with nateglinide/metformin significantly reduced HbA(1c) from baseline (7.8 +/- 0.2% to 6.6 +/- 0.1%; Delta = -1.2 +/- 0.2%, p < 0.001), as did glyburide/metformin (7.7 +/- 0.1% to 6.5 +/- 0.1%; Delta = -1.2 +/- 0.1%, p < 0.001). There was no difference between treatments (p = 0.310). One nateglinide/metformin-treated patient experienced a mild hypoglycaemic episode compared with eight episodes in eight patients on glyburide/metformin; one severe episode led to discontinuation. Target HbA(1c) (<7.0%) was achieved by 60% of patients receiving nateglinide (Study 1) and 70% of nateglinide/metformin-treated patients (Study 2).

CONCLUSION

Initial drug treatment with nateglinide, alone or in combination with metformin, is well tolerated and produces clinically meaningful improvements in glycaemic control in elderly patients with T2DM.

Pharmacokinetics and pharmacodynamics of glimepiride in type 2 diabetic patients: compared effects of once- versus twice-daily dosing

To compare the pharmacokinetic and pharmacodynamic effects of glimepiride between once- and twice-daily dosing in type 2 diabetic patients. Eight Japanese type 2 diabetic patients, who had been treated with 2 mg glimepiride alone over 4 weeks (age 40-70, body mass index <or=25 kg/m2, hemoglobin A 1C<8.0%), were randomly assigned to the crossover study with glimepiride 2 mg once-daily and 1 mg twice-daily for 4 weeks for each regime. Serum concentrations of glimepiride, plasma glucose, insulin and C-peptide were measured over 24 h at the fixed time intervals on the last day of each crossover period, and HbA 1C was measured at the same day. Pharmacokinetic profiles in two regimens were different to each others; a single peak of serum glimepiride concentration was observed in once-daily, and double peaks in twice-daily dosing. Drug concentration increased immediately, and peaked at 2 h after administration irrespective of dosage. Cmax value in once-daily dose was higher than those in twice-daily doses. AUC values were not different between two regimens. Pharmacodynamic profiles for plasma glucoses, serum insulin and C-peptide showed no statistically significant differences between two regimens, and parameters were not different each other. Analyses of adverse events and laboratory data demonstrated a favorable safety profile of glimepiride. The present results suggest that glimepiride may be suitable for once-daily dosing with respect to clinical usefulness.

Improvement of insulin sensitivity and beta-cell function by nateglinide and repaglinide in type 2 diabetic patients - a randomized controlled double-blind and double-dummy multicentre clinical trial

AIM

To evaluate the efficacy of nateglinide vs. repaglinide in blood glucose (BG) control and the effect on insulin resistance and beta-Cell function in patients with type 2 diabetes.

METHODS

A randomized controlled double-blind and double-dummy multicentre clinical trial was conducted. A total of 230 Chinese patients with type 2 diabetes were enrolled in five clinical centres. The patients were divided randomly into group A [repaglinide 1.0 mg three times daily (t.i.d.), n = 115] or group B (nateglinide 90 mg t.i.d., n = 115). At baseline and end of the 12-week clinical trial, standard mixed meal tolerance tests were performed.

RESULTS

A total of 223 patients (96.9%) completed the trial. There was no significant difference between repaglinide and nateglinide groups in the effects of reducing fasting blood glucose (FBG), 30-, 60- and 120-min BG during 12 weeks (p > 0.05). At week 12, no significant difference was shown between the two groups in BG or haemoglobin A(1c) (HbA(1c)) (p > 0.05). However, the effect on HbA(1c) in repaglinide group was stronger than that in nateglinide group (p < 0.05). After 12-week treatment, area under the curve (AUC) of BG decreased (p < 0.05), and AUC of insulin and C-peptide (CP) increased in both groups (p < 0.05). The effects of nateglinide on AUC of BG, insulin and CP were similar to that of repaglinide (p > 0.05). There was no significant difference between the two groups in AUC of BG, insulin or CP in week 12 (p > 0.05). Furthermore, homeostasis model assessment of insulin resistance (HOMA-IR) and beta-cell function indexes measured by HOMA-beta, DeltaI(30)/DeltaG(30) and (DeltaI(30)/DeltaG(30))/HOMA-IR were improved significantly in both groups during 12 weeks (p < 0.05). The effects of improving HOMA-IR and beta-cell function indexes in nateglinide group were comparable with that of repaglinide group (p > 0.05).

CONCLUSIONS

The efficacy of repaglinide and nateglinide in FBG, postprandial glucose excursion and early-phase insulin secretion is similar. But the effect of repaglinide 1.0 mg t.i.d. on HbA(1c) is stronger than that of nateglinide 90 mg t.i.d.. This trial had shown that nateglinide and repaglinide could comparably improve insulin sensitivity and beta-cell function.

Antidiabetic medications in overweight/obese patients with type 2 diabetes: drawbacks of current drugs and potential advantages of incretin-based treatment on body weight

The vast majority of patients with type 2 diabetes are overweight or obese. Lifestyle intervention to lose weight is recommended in most diabetic patients to improve glycaemic control and reduce associated risk factors for microvascular and macrovascular complications. Even modest weight loss can significantly improve glucose homeostasis and lessen cardiometabolic risk factors, although achieving this level of weight reduction remains difficult for many patients. Complicating the matter, many agents used to target hyperglycaemia are associated with weight gain, making management of overweight or obese patients with type 2 diabetes quite challenging. Incretin-based therapies with the new classes of glucagon-like peptide-1 mimetics (e.g. exenatide, liraglutide) and dipeptidyl peptidase 4 (DPP-4) inhibitors (e.g. sitagliptin, vildagliptin) may be of particular value in the treatment of overweight/obese type 2 diabetic patients because of their efficacy in improving glycaemic control and their favourable or neutral effects on body weight. In addition, DPP-4 inhibitors have a low risk for causing hypoglycaemia, undesirable gastrointestinal effects, or other prominent adverse effects that might limit their use. These classes of drugs hold promise for the treatment of type 2 diabetes, alone or in combination with other classes of antidiabetic agents.

Meglitinide analogues for type 2 diabetes mellitus

BACKGROUND

In type 2 diabetes mellitus, impairment of insulin secretion is an important component of the disease. Meglitinide analogues are a class of oral hypoglycaemic agents that increase insulin secretion, in particular, during the early phase of insulin release.

OBJECTIVES

The aim of this review was to assess the effects of meglitinide analogues in patients with type 2 diabetes mellitus.

SEARCH STRATEGY

We searched several databases including The Cochrane Library, MEDLINE and EMBASE. We also contacted manufacturers and searched ongoing trials databases, and the American Diabetes Association (ADA) and European Association for the Study of Diabetes (EASD) websites.

SELECTION CRITERIA

We included randomised controlled, parallel or cross-over trials comparing at least 10 weeks of treatment with meglitinide analogues to placebo, head-to-head, metformin or in combination with insulin.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed trial quality.

MAIN RESULTS

Fifteen trials involving 3781 participants were included. No studies reported the effect of meglitinides on mortality or morbidity. In the eleven studies comparing meglitinides to placebo, both repaglinide and nateglinide resulted in a reductions in glycosylated haemoglobin (0.1% to 2.1% reduction in HbA1c for repaglinide; 0.2% to 0.6% for nateglinide). Only two trials compared repaglinide to nateglinide (342 participants), with greater reduction in glycosylated haemoglobin in those receiving repaglinide. Repaglinide (248 participants in three trials) had a similar degree of effect in reducing glycosylated haemoglobin as metformin. Nateglinide had a similar or slightly less marked effect on glycosylated haemoglobin than metformin (one study, 355 participants). Weight gain was generally greater in those treated with meglitinides compared with metformin (up to three kg in three months). Diarrhoea occurred less frequently and hypoglycaemia occurred more frequently but rarely severely enough as to require assistance.

AUTHORS' CONCLUSIONS

Meglitinides may offer an alternative oral hypoglycaemic agent of similar potency to metformin, and may be indicated where side effects of metformin are intolerable or where metformin is contraindicated. However, there is no evidence available to indicate what effect meglitinides will have on important long-term outcomes, particularly mortality.

Nateglinide and Mitiglinide, but Not Sulfonylureas, Induce Insulin Secretion through a Mechanism Mediated by Calcium Release from Endoplasmic Reticulum

Nateglinide and mitiglinide (glinides) are characterized as rapid-onset and short-acting insulinotropic agents. Although both compounds do not have a sulfonylurea structure, it has been postulated that insulin secretion is preceded by their binding to Kir6.2/SUR1 complex, and a mechanism of insulin secretion of glinides has been accounted for by this pathway. However, we hypothesized the involvement of additional mechanisms of insulin secretion enhanced by glinides, and we analyzed the pattern of time course of insulin secretion from MIN6 cells with the existence of agents that have specific pharmacologic actions. Dose-dependent effects of tolbutamide, glibenclamide, nateglinide, and mitiglinide were observed. Insulin secretion induced by 3 microM tolbutamide and 1 nM glibenclamide was completely inhibited by 10 microM diazoxide and 3 microM verapamil, although the latter half-component of insulin secretion profile induced by 3 microM nateglinide or 30 nM mitiglinide remained with the existence of those agents. Glinides enhanced insulin secretion even in Ca2+-depleted medium, and its pattern of secretion was same as the pattern with existence of verapamil. The latter half was suppressed by 1 microM dantrolene, and concomitant addition of verapamil and dantrolene completely suppressed the entire pattern of insulin secretion enhanced by nateglinide. Thus, we conclude that glinide action is demonstrated through two pathways, dependently and independently, from the pathway through K(ATP) channels. We also demonstrated that the latter pathway involves the intracellular calcium release from endoplasmic reticulum via ryanodine receptor activation.

Nateglinide improves postprandial hyperglycemia and insulin secretion in renal transplant recipients

BACKGROUND

Postprandial hyperglycemia (PPHG) frequently occurs among renal transplant recipients (RTR). Reduced early insulin response (EIR) after a meal leads to impaired suppression of endogenous glucose production and subsequently PPHG, which is a risk factor for cardiovascular disease. Nateglinide is a rapid acting insulin secretagogue inducing an EIR after a meal. Our main objective was to investigate the safety and effect of nateglinide treatment on postprandial plasma glucose excursions and insulin secretion in RTR with PPHG.

PATIENTS AND METHODS

A total of 14 Caucasian RTR with new-onset diabetes mellitus (NODM; n = 6) or impaired glucose tolerance (IGT; n = 8) were included. The insulin response and glucose excursions were measured for 240 min after a standardized liquid meal at baseline and after two-wk treatment with nateglinide.

RESULTS

Treatment with nateglinide was followed by a significant decrease in mean two-h plasma glucose from 10.5 mmol/L (3.1) to 7.6 mmol/L (2.1; p < 0.001) and a decline in total postprandial area under the curve (AUC) of glucose concentration (p < 0.001). Both estimated EIR and the late insulin response increased significantly (p = 0.008 and p = 0.003, respectively). No serious adverse event was observed during the study period.

CONCLUSIONS

Treating RTR with nateglinide for two-wk significantly improved PPHG, increased the insulin response following a standardized meal and was well tolerated.

A systematic review and meta-analysis of hypoglycemia and cardiovascular events: a comparison of glyburide with other secretagogues and with insulin

OBJECTIVE

Glyburide is the most widely used sulfonylurea but has unique pharmacodynamic properties that may increase harm. We hypothesized that glyburide causes more hypoglycemia and cardiovascular events than other secretagogues or insulin.

RESEARCH DESIGN AND METHODS

Data sources were Medline, Embase, Cochrane, and three other web-based clinical trial registers (1966-2005). Parallel, randomized, controlled trials in people with type 2 diabetes comparing glyburide monotherapy with monotherapy using secretagogues or insulin were selected. Outcomes were hypoglycemia, glycemic control, cardiovascular events, body weight, and death. Titles and abstracts of 1,806 publications were reviewed in duplicate and 21 relevant articles identified. Data on patient characteristics, interventions, outcomes, and validity were extracted in duplicate using predefined criteria.

RESULTS

Glyburide was associated with a 52% greater risk of experiencing at least one episode of hypoglycemia compared with other secretagogues (relative risk 1.52 [95% CI 1.21-1.92]) and with 83% greater risk compared with other sulfonylureas (1.83 [1.35-2.49]). Glyburide was not associated with an increased risk of cardiovascular events (0.84 [0.56-1.26]), death (0.87 [0.70-1.07]), or end-of-trial weight (weighted mean difference 1.69 kg [95% CI -0.41 to 3.80]) compared with other secretagogues. Limitations included suboptimal reporting of original trials. Loss to follow-up exceeded 20% in some studies, and major hypoglycemia was infrequently reported.

CONCLUSIONS

Glyburide caused more hypoglycemia than other secretagogues and other sulfonylureas. Glyburide was not associated with an increased risk of cardiovascular events, death, or weight gain.

Glucocorticoid-induced diabetes mellitus: prevalence and risk factors in primary renal diseases

BACKGROUND/AIMS

In patients with primary renal diseases the current knowledge of hyperglycemia associated with corticosteroid therapy is limited. We therefore examined the prevalence and risk factors of glucocorticoid-induced diabetes mellitus (DM) in primary renal diseases.

METHODS

Patients were recruited with primary renal diseases who were started on corticosteroids between April 2002 and June 2005. In patients with DM, an impaired fasting glucose level and/or positive urinary glucose analyses before corticosteroids therapy were excluded.

RESULTS

During corticosteroid therapy (initial dose: prednisolone 0.75 +/- 0.10 mg/kg/day), DM was newly diagnosed in 17 (40.5%) of 42 patients. All of the 17 patients were diagnosed as having DM by postprandial hyperglycemia at 2 h after lunch, although they had normal fasting blood glucose levels. Age (OR 1.40, 95% CI 1.06-1.84) and body mass index (OR 1.87, 95% CI 1.03-3.38) were determined as independent risk factors for glucocorticoid-induced DM.

CONCLUSION

Over 40% of patients with primary renal disease developed DM during treatment with corticosteroids. A high age and high body mass index are the independent risk factors for glucocorticoid-induced DM. 24-hour urinary glucose analyses and postprandial plasma glucose are useful for detecting glucocorticoid-induced DM.

Meglitinide analogues: a review of clinical data focused on recent trials

Glinides represent a chemically heterogeneous new class of insulin-secreting agents characterized by a rapid onset and short duration of action. They act by closure of the ATP-dependant K channel. Repaglinide, the only glinide available in France, has an equivalent HbA1c lowering effect to conventional sulfonylureas but reduces predominantly postprandial glucose levels. Several studies indicate a decreased risk of hypoglycaemias, particularly nocturnal or in case of a shift or omission of a meal. This drug appears particularly useful in early stage type 2 diabetes or in combination with metformin. The only significant drug-drug interaction concerns gemfibrozil. Due to its hepatic metabolism and biliary elimination, repaglinide can be used in patients with renal insufficiency. Nateglinide has a even shorter duration of action and has almost no effect on fasting plasma glucose levels. For this reason, this drug is only indicated in combination with metformin in the countries where it is licensed. Several experimental data suggest that glinides could preserve B cell function over time better than hypoglycaemic sulfonylureas, and that the improvement of post-prandial glucose levels could exert a long term protective cardiovascular effect.

Long-term effects of exenatide therapy over 82 weeks on glycaemic control and weight in over-weight metformin-treated patients with type 2 diabetes mellitus

AIM

The ability of the incretin mimetic exenatide to improve glycaemic control and reduce body weight was assessed over 82 weeks in patients with type 2 diabetes failing to achieve glycaemic control with maximally effective doses of metformin.

METHODS

In this interim 82-week analysis, 150 (total cohort) of an eligible population of 183 patients opted to continue exenatide treatment in an uncontrolled open-label extension of a 30-week double-blind, placebo-controlled trial. Of these, 92 patients (completer cohort) achieved 82 weeks of exenatide therapy. Patients continued metformin throughout the study.

RESULTS

At the end of the placebo-controlled trial, exenatide resulted in an haemoglobin A1c (HbA1c) reduction from baseline of -1.0 +/- 0.1% (mean +/- SE) (exenatide treatment arms), with durable HbA1c reductions after 82 weeks of -1.3 +/- 0.1%. The percent of patients who achieved HbA1c < or = 7% at weeks 30 and 82 was 46 and 59% respectively. After 30 weeks, exenatide caused a reduction in weight from baseline of -3.0 +/- 0.6 kg, with a progressive reduction in weight of -5.3 +/- 0.8 kg after 82 weeks. In addition, exenatide treatment produced clinically significant improvements in cardiovascular risk factors after 82 weeks. The most frequent adverse event after 30 and 82 weeks of exenatide was nausea, which was generally of mild-or-moderate intensity. It decreased in incidence after initiation in the controlled trial and the uncontrolled open-label extension. Hypoglycaemia was rare, with no severe events.

CONCLUSION

Exenatide was generally well tolerated, producing a durable reduction in HbA1c and a progressive reduction in weight over 82 weeks in patients with type 2 diabetes failing to achieve glycaemic control with metformin.

Comparison of nateglinide and gliclazide in combination with metformin, for treatment of patients with Type 2 diabetes mellitus inadequately controlled on maximum doses of metformin alone

AIM

To compare the effects of nateglinide plus metformin with gliclazide plus metformin on glycaemic control in patients with Type 2 diabetes.

METHODS

Double-blind, double-dummy, parallel group, randomized, multicentre study over 24 weeks. Patients with inadequate glucose control on maximal doses of metformin were randomized to additionally receive nateglinide (n = 133) or gliclazide (n = 129). Changes from baseline in HbA1c, fasting plasma glucose (FPG) and mealtime glucose and insulin excursions were examined.

RESULTS

HbA1c was significantly (P < 0.001) decreased from baseline in both treatment groups (mean changes: nateglinide -0.41%, gliclazide -0.57%), but with no significant difference between treatments. Proportions of patients achieving a reduction of HbA1c >or= 0.5% or an end point HbA1c < 7% were also similar (nateglinide 58.1%, gliclazide 60.2%). Changes from baseline in FPG were similarly significant in both treatment groups (nateglinide -0.63, gliclazide -0.82 mmol/l). Reduction from baseline in maximum postprandial glucose excursion were significant in the nateglinide group only (nateglinide -0.71, gliclazide -0.10 mmol/l; P = 0.037 for difference). Postprandial insulin levels were significantly higher with nateglinide compared with gliclazide. The overall rate of hypoglycaemia events was similar in the nateglinide group compared with the gliclazide group.

CONCLUSIONS

No significant difference was seen between nateglinide plus metformin and gliclazide plus metformin in terms of HbA1c. However, the nateglinide combination demonstrated better postprandial glucose control.

Efficacy and adverse effects of nateglinide in early type 2 diabetes. Comparison with voglibose in a cross-over study

An open-label prospective cross-over trial was performed to compare the efficacy and adverse effects of nateglinide with those of voglibose on Japanese early type 2 diabetes (who were oral hypoglycemic agent naïve and whose HbA(1C) levels were between 7.0 and 7.9% before treatment). Fourteen patients received 270 mg/day of nateglinide and 15 patients received 0.6 mg/day of voglibose. After 12 weeks of either therapy, the drugs were switched and treatment was continued for another 12 weeks. After 3-month treatment with each drug, HbA(1C) value decreased significantly (baseline HbA(1C) 7.24 +/- 0.42%, 6.70 +/- 0.47% with nateglinide: p<0.01, 6.93 +/- 0.62% with voglibose: p<0.05) but the difference in the effect between nateglinide and voglibose was not significant (p = 0.121). Symptoms related to hypoglycemia (e.g., increased appetite, palpitation, sweating, tremor) were scarcely observed with either voglibose or nateglinide treatments. Abdominal fullness/borborygmi was frequently reported, with variable severity, by patients on voglibose but this was absent or mild in those on nateglinide. After completion of both arms of the study, more patients favored nateglinide than voglibose. Our results suggest that nateglinide is an effective and safe drug in the treatment of early type 2 diabetes, similar to voglibose.

Beneficial effects of nateglinide on insulin resistance in type 2 diabetes

Nateglinide, a rapid insulin secretagogue, is known to facilitate the early phase of insulin secretion and has been used for the treatment of type 2 diabetic patients with postprandial hyperglycemia. The aim of this study is to evaluate the effect of nateglinide on insulin resistance as well as insulin secretory defects in type 2 diabetic patients. Insulin secretion ability was evaluated by the hyperglycemic clamp test, and insulin sensitivity was evaluated by the euglycemic hyperinsulinemic clamp test, using an artificial pancreas. The hyperglycemic clamp test showed that a 7-day treatment with nateglinide significantly increased insulin secretion in response to high glucose. Interestingly, although nateglinide is known to facilitate insulin secretion, daily urinary C-peptide excretion was decreased after nateglinide treatment. Moreover, in the euglycemic hyperinsulinemic clamp test, glucose infusion rate was significantly increased by nateglinide treatment, indicating that nateglinide functions to decrease insulin resistance. Nateglinide ameliorates insulin resistance as well as insulin secretory defects in type 2 diabetic patients.

Improved prandial glucose control with lower risk of hypoglycemia with nateglinide than with glibenclamide in patients with maturity-onset diabetes of the young type 3

OBJECTIVE

To study the effect of the short-acting insulin secretagogue nateglinide in patients with maturity-onset diabetes of the young type 3 (MODY3), which is characterized by a defective insulin response to glucose and hypersensitivity to sulfonylureas.

RESEARCH DESIGN AND METHODS

We compared the acute effect of nateglinide, glibenclamide, and placebo on prandial plasma glucose and serum insulin, C-peptide, and glucagon excursions in 15 patients with MODY3. After an overnight fast, they received on three randomized occasions placebo, 1.25 mg glibenclamide, or 30 mg nateglinide before a standard 450-kcal test meal and light bicycle exercise for 30 min starting 140 min after the ingestion of the first test drug.

RESULTS

Insulin peaked earlier after nateglinide than after glibenclamide or placebo (median [interquartile range] time 70 [50] vs. 110 [20] vs. 110 [30] min, P = 0.0002 and P = 0.0025, respectively). Consequently, compared with glibenclamide and placebo, the peak plasma glucose (P = 0.031 and P < 0.0001) and incremental glucose areas under curve during the first 140 min of the test (P = 0.041 and P < 0.0001) remained lower after nateglinide. The improved prandial glucose control with nateglinide was achieved with a lower peak insulin concentration than after glibenclamide (47.0 [26.0] vs. 80.4 [71.7] mU/l; P = 0.023). Exercise did not induce hypoglycemia after nateglinide or placebo, but after glibenclamide six patients experienced symptomatic hypoglycemia and three had to interrupt the test.

CONCLUSIONS

A low dose of nateglinide prevents the acute postprandial rise in glucose more efficiently than glibenclamide and with less stimulation of peak insulin concentrations and less hypoglycemic symptoms.

Therapeutic efficacy of mitiglinide combined with once daily insulin glargine after switching from multiple daily insulin regimen of aspart insulin and glargine in patients with type 2 diabetes mellitus

Mitiglinide is novel class of rapid-acting insulin secretagogues, which have been widely used alone or in combination with other oral hypoglycemic drugs to improve postprandial hyperglycemia in early type 2 diabetes. While mitiglinide enhances postprandial requirement of insulin, the efficacy of mitiglinide combined with insulin has yet to be established. We investigated the efficacy of mitiglinide combined with insulin glargine, the first soluble insulin analog that has a flat and prolonged effect. After control with the intensive regimen (daily aspart insulin and glargine), 30 inpatients with type 2 diabetes were switched to premeal mitiglinide combined with once daily insulin glargine (mitiglinide regimen), and daily profiles of blood glucose level were compared under each regimen. Fifteen patients showed similar control of hyperglycemia with mitiglinide regimen and intensive insulin regimen, assessed by M value (<32), while the remaining 15 showed worsening under the mitiglinide regimen. The patients who were well controlled with mitiglinide regimen were significantly younger (51.9 +/- 16.0 years, p<0.005) and heavier (body mass index: 25.7 +/- 3.3 kg/m(2), p<0.05) than those who were not (67.9 +/- 8.7 and 23.0 +/- 3.1, respectively). Moreover, insulin doses of aspart per body weight were significantly fewer in effective group than in ineffective group. Duration of diabetes was shorter in the effective group, albeit insignificantly. Previous treatment before starting intensive insulin regimen, such as insulin and sulfonylurea, was not different between the two groups. Our results suggest that mitiglinide plus insulin glargine combination therapy is useful for lowering both fasting and postprandial hyperglycemia in a subpopulation of type 2 diabetes. The long-term effects of such treatment need to be established in future studies.

Nateglinide with glibenclamide examination using the respiratory quotient (RQ)

PURPOSE

The respiratory quotient (RQ) is useful for evaluating glucose and lipid metabolism in vivo. We previously reported that the RQ value, even after fasting, was high in diabetics being treated with sulphonylurea (SU), which might explain the accumulation of fat, leading to weight gain in such individuals. In the present study, we measured the RQ in type II diabetic patients who were being treated with a rapid-onset/short-duration insulinotropic agent, nateglinide, and compared it with those being treated with SU.

METHODS

A glucose tolerance test was performed in 20 patients with type II diabetes mellitus treated with nateglinide and in 14 patients treated with SU, and the RQ was simultaneously measured.

RESULTS

The RQ values in the patients treated with nateglinide, were similar to those in healthy adults, but was lower than in those treated with SU. No weight gain was observed in patients treated with nateglinide.

CONCLUSION

A significant weight gain was reported in subjects treated with SU, accompanied by an increase in RQ. However, weight gain was less frequent in diabetics treated with nateglinide.

Nateglinide--current and future role in the treatment of patients with type 2 diabetes mellitus

Therapy for type 2 diabetes mellitus should aim to control not only fasting, but also postprandial glucose levels. Nateglinide, a d-phenylalanine derivative, restores postprandial early phase insulin secretion in a transient and glucose-sensitive manner without affecting basal insulin levels. As nateglinide is administered immediately before meals it provides greater lifestyle flexibility than agents that require patients to eat to avoid hypoglycemic events (e.g. long-acting sulfonylureas). In randomised, double-blind trials in patients with type 2 diabetes, nateglinide monotherapy (mealtime treatment of 120 mg three times daily) significantly improved long-term glycaemic control by significantly reducing glyated haemoglobin (HbA 1c) and preventing mealtime glucose spikes. The combination of nateglinide with insulin-sensitising agents, for example, metformin and thiazolidinediones, addresses the dual defects of loss of insulin secretion and insulin resistance to provide optimal management of type 2 diabetes, and more patients achieve HbA 1c goal with nateglinide combination therapy rather than with monotherapy with other oral agents. Nateglinide also restores early insulin secretion and reduces postprandial hyperglycaemia in prediabetic subjects with impaired glucose tolerance (IGT) and appears similarly effective in elderly and non-elderly populations with type 2 diabetes. It has an excellent safety and tolerability profile, with a low propensity to cause hypoglycaemia due to its transient, selective effect on early phase insulin secretion. Nateglinide as monotherapy or combination therapy is an effective option to reduce mealtime glucose in patients with type 2 diabetes. The results of ongoing research into its potential role in delaying progression to overt diabetes, and protecting against cardiovascular events, in prediabetic patients with IGT are awaited.

PRESERVE-beta: two-year efficacy and safety of initial combination therapy with nateglinide or glyburide plus metformin

OBJECTIVE

To compare long-term efficacy and safety of initial combination therapy with nateglinide/metformin versus glyburide/metformin.

RESEARCH DESIGN AND METHODS

We conducted a randomized, multicenter, double-masked, 2-year study of 428 drug-naïve patients with type 2 diabetes. Patients received 120 mg a.c. nateglinide or 1.25 mg q.d. glyburide plus 500 mg q.d. open-label metformin for the initial 4 weeks. During a subsequent 12-week titration period, glyburide and metformin were increased by 1.25- and 500-mg increments to maximum daily doses of 10 and 2,000 mg, respectively, if biweekly fasting plasma glucose (FPG) > or = 6.7 mmol/l. Nateglinide was not titrated. Blinding was maintained by use of matching placebo for nateglinide and glyburide. An 88-week monitoring period followed, during which HbA1c (A1C), FPG, and postprandial glucose excursions (PPGEs) during an oral glucose tolerance test were measured.

RESULTS

In nateglinide/metformin-treated patients, mean A1C was 8.4% at baseline and 6.9% at week 104. In glyburide/metformin-treated patients, mean A1C was 8.3% at baseline and 6.8% at week 104 (P < 0.0001 vs. baseline for both treatments, NS between treatments). The deltaPPGE averaged -96 +/- 19 (P < 0.0001) and -57 +/- 22 mmol.l(-1).min(-1) (P < 0.05) in patients receiving nateglinide/metformin and glyburide/metformin, respectively, whereas deltaFPG was -1.6 +/- 0.2 (P < 0.0001) and -2.4 +/- 0.2 mmol/l (P < 0.0001) in patients receiving nateglinide/metformin and glyburide/metformin, respectively (P < 0.01 between groups). Thus, the two treatments achieved similar efficacy with differential effects on FPG versus PPGE. Hypoglycemia occurred in 8.2 and 17.7% of patients receiving nateglinide/metformin and glyburide/metformin, respectively.

CONCLUSIONS

Similar good glycemic control can be maintained for 2 years with either treatment regimen, but nateglinide/metformin may represent a safer approach to initial combination therapy.