Comparison of the efficacy and safety of once-daily insulin degludec/insulin aspart (IDegAsp) and long-acting second-generation basal insulin (insulin degludec and insulin glargine 300 units/mL) in insulin-naïve Japanese adults with type 2 diabetes: a pilot, randomized, controlled study

To examine the efficacy and safety of once-daily insulin degludec/insulin aspart (IDegAsp) or once-daily second-generation basal insulin analogs (insulin degludec and insulin glargine 300 units/mL) in insulin-naïve Japanese adults with type 2 diabetes in routine clinical practice. A 12-week multicenter, open-label, randomized, pilot study was performed in 52 subjects with type 2 diabetes treated with oral antidiabetic drugs (OADs). Subjects were randomized to once-daily IDegAsp (n = 26) or basal insulin (n = 26). The primary endpoint was percent change in HbA1c from baseline to week 12. Furthermore, it was analyzed post hoc in subgroups stratified by baseline HbA1c. During a follow-up period, percent change in HbA1c was not significantly different between the two groups (p = 0.161). Daily insulin doses and frequency of overall hypoglycemia were also similar in the two groups. In post hoc analyses, once-daily basal insulin was more effective than IDegAsp in subjects with HbA1c more than or equal to 8.5% (p < 0.05); however, in subjects with HbA1c less than 8.5%, once-daily IDegAsp showed a significant improvement in percent change in HbA1c at week 12, compared with basal insulin (p < 0.01). Although there was no apparent difference in the HbA1c-lowering effects between two groups, when compared in subjects with HbA1c less than 8.5%, once-daily IDegAsp showed a significant effect in comparison with once-daily basal insulin. These findings suggest that the baseline HbA1c level might provide the important information for choosing IDegAsp or basal insulin in patients insufficiently controlled with OADs. This trial was registered with UMIN (no. UMIN000035431).

A 1-year, prospective, observational study of Japanese outpatients with type 1 and type 2 diabetes switching from insulin glargine or detemir to insulin degludec in basal-bolus insulin therapy (Kumamoto Insulin Degludec Observational study)

AIMS/INTRODUCTION

The aim of the present prospective observational study was to assess long-term efficacy and safety of insulin degludec as a part of a basal-bolus therapy for Japanese patients with type 1 or type 2 diabetes in routine clinical practice.

MATERIALS AND METHODS

In the present study, 93 type 1 diabetes patients and 135 type 2 diabetes patients treated with insulin glargine or detemir were switched from their basal insulin to insulin degludec. The primary end-points were the changes in glycated hemoglobin (HbA1c) from baseline at 3, 6 and 12 months. The secondary end-points were changes in body mass index, insulin dose, frequency of hypoglycemia and adverse events.

RESULTS

HbA1c levels from baseline were significantly reduced at 3, 6, and 12 months by 0.4, 0.4 and 0.3% in type 1 diabetes patients, respectively, and by 0.5, 0.5 and 0.3% in type 2 diabetes patients, respectively. Body mass index in type 1 diabetes patients increased significantly (P < 0.05), whereas that in type 2 diabetes patients did not change. Basal insulin dose decreased significantly at 3 months after switching (P < 0.05), and returned baseline dose at 12 months in type 1 diabetes and type 2 diabetes patients. The frequency of both total and nocturnal hypoglycemia decreased significantly in type 1 diabetes and type 2 diabetes patients (P < 0.05). The result of multiple regression analysis showed that baseline HbA1c was a significant independent variable of the percentage change in HbA1c with switching.

CONCLUSION

In both type 1 diabetes and type 2 diabetes patients, switching from insulin glargine or insulin detemir to insulin degludec led to improvement of glycemic control with a significant reduction of hypoglycemia.

Comparison of the efficacy of sitagliptin and glimepiride dose-up in Japanese patients with type 2 diabetes poorly controlled by sitagliptin and glimepiride in combination

Aims/Introduction

The goal of the study was to examine the effects of sitagliptin dose‐up or glimepiride dose‐up in Japanese patients with type 2 diabetes who were controlled inadequately by sitagliptin and glimepiride in combination.

Materials and Methods

A multicenter, prospective, randomized, open‐label study was carried out in 50 patients with type 2 diabetes treated with sitagliptin and low‐dose glimepiride. The patients were randomly assigned to receive the addition of 50 mg/day sitagliptin or 0.5 mg/day glimepiride. The primary end‐point was the percentage change in glycated hemoglobin (HbA1c).

Results

During a follow‐up period, the difference in the percentage changes in HbA1c between the two groups was not significant (P = 0.13). However, HbA1c was significantly decreased by glimepiride dose‐up (P < 0.01 vs baseline), but not by sitagliptin dose‐up (P = 0.74). Univariate linear regression analyses showed that the percentage change in HbA1c was significantly associated with the serum level of arachidonic acid (AA) in both groups.

Conclusions

There was no significant difference in the HbA1c‐lowering effects between the two groups. However, a significant HbA1c‐lowering effect from baseline of glimepiride dose‐up was found, and the AA level showed a negative correlation with the decrease in HbA1c in the sitagliptin dose‐up group, but a positive correlation in the glimepiride dose‐up group. These findings suggest that the AA level is associated with HbA1c reduction in response to dose‐up with these drugs in patients with type 2 diabetes in a combination therapy with sitagliptin and glimepiride. This trial was registered with UMIN (no. 000009544).

Efficacy and safety of sitagliptin as add-on therapy on glycemic control and blood glucose fluctuation in Japanese type 2 diabetes subjects ongoing with multiple daily insulin injections therapy

To assess the efficacy and safety of adding sitagliptin, an oral dipeptidyl peptidase-4 inhibitor, in subjects with type 2 diabetes inadequately controlled with multiple daily insulin injections therapy (MDI). HbA1c, 1,5-anhydroglucitol (1,5-AG), body mass index (BMI), insulin doses, six-point self-measured plasma glucose (SMPG) profiles were assessed before, after 12 weeks, and after 24 weeks of MDI with 50 mg/day of sitagliptin in 40 subjects with type 2 diabetes. Safety endpoints included hypoglycemia and any adverse events. HbA1c significantly decreased during the first 12 weeks ( -0.64±0.60%), and was sustained over 24 weeks ( -0.69±0.85%). 1,5-AG increased significantly from 7.5±4.5 μg/mL at baseline to 9.6±5.5 μg/mL after 24 weeks. The bolus insulin dose at 12 weeks was decreased, and the mean plasma glucose, the SD of daily glucose, M-value, and the mean amplitude of glycemic excursions (MAGE) also decreased significantly as compared with baseline values. BMI and frequency of hypoglycemia were not changed significantly. Univariate linear regression analyses revealed that % change in HbA1c was significantly associated with BMI, and % changes in the indexes of glycemic instability (SD of daily glucose and MAGE) were significantly associated with age. In conclusion, adding sitagliptin to MDI significantly improved glycemic control and decreased the daily glucose fluctuation in subjects with type 2 diabetes inadequately controlled with MDI, without weight gain or an increase in the incidence of hypoglycemia. This trial was registered with UMIN (no. UMIN000010157).

Ezetimibe improves glucose metabolism by ameliorating hepatic function in Japanese patients with type 2 diabetes

Aims/Introduction:  Several experimental studies have shown that ezetimibe improves steatosis and insulin resistance in the liver. This suggests that ezetimibe may improve glucose metabolism, as well as lipid metabolism, by inhibiting hepatic lipid accumulation. Therefore, we compared HbA1c levels after 3 months ezetimibe treatment with baseline levels in patients with type 2 diabetes and examined the factors associated with reductions in HbA1c following ezetimibe administration.

MATERIALS AND METHODS

  Lipid profiles, hepatic function, and HbA1c were assessed before and after 3 months treatment with 10 mg/day ezetimibe in 96 patients with type 2 diabetes and hypercholesterolemia. Regression analysis was used to investigate associations between metabolite levels and the percentage change in HbA1c.

RESULTS

  Low-density lipoprotein-cholesterol was significantly lower after 3 months treatment compared with baseline, and HbA1c decreased in approximately 50% of patients. Univariate linear regression analyses showed that changes in HbA1c were significantly associated with serum alanine aminotransferase (ALT), the aspartate aminotransferase (AST)/ALT ratio, and age. Two-tailed chi-square tests revealed that serum ALT ≥35 IU/L and an AST/ALT ratio <1.0 were significantly associated with decreases in HbA1c following ezetimibe administration.

CONCLUSIONS

  The results of the present study indicate that ezetimibe may improve glucose metabolism. Serum ALT levels and the AST/ALT ratio were useful predictors of a glucose metabolism response to ezetimibe. This trial was registered with UMIN (no. UMIN000005307). (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00147.x, 2011).

Effects of olmesartan, an angiotensin II receptor blocker, on peripheral insulin sensitivity in Japanese subjects with type 2 diabetes and hypertension

OBJECTIVE

Several studies have assessed the efficacy of angiotensin receptor blockers (ARBs) on peripheral insulin sensitivity using the euglycemic hyperinsulinemic clamp technique in hypertensive subjects. However, these subjects were mostly non-diabetic, and some studies showed that ARB treatment did not improve insulin sensitivity. Thus, it is still uncertain whether ARBs could improve insulin sensitivity in subjects with hypertension and diabetes. Therefore, we evaluated the effect of olmesartan on peripheral insulin sensitivity in subjects with type 2 diabetes and hypertension using M/I value during the euglycemic-hyperinsulinemic clamp technique.

METHODS

We enrolled 10 Japanese subjects with type 2 diabetes and hypertension who had never taken antihypertensive agents. Their blood pressure, fasting plasma glucose level, HbA1c and glucose utilization rate during euglycemic-hyperinsulinemic clamp (M/I value) were examined before and after 6 months of treatment with 10-20 mg/day olmesartan (mean: 13.0 mg/day).

RESULTS

Blood pressure decreased significantly from 156/88 mmHg before starting olmesartan to 135/76 mmHg after 6 months of olmesartan treatment. The mean M/I value increased significantly from 6.33 ± 3.19 (mg/kg/min/mU/L) × 100 to 8.11 ± 4.20 (mg/kg/min/mU/L) × 100. Peripheral insulin sensitivity improved in eight out of ten subjects. Fasting glucose levels and HbA1c levels also decreased significantly.

CONCLUSION

These results indicate that olmesartan improves glucose metabolism by improving the peripheral insulin sensitivity in subjects with type 2 diabetes.

Development of a highly responsive needle-type glucose sensor using polyimide for a wearable artificial endocrine pancreas

To produce a long-life, stable, miniature glucose sensor for a wearable artificial endocrine pancreas (WAEP), we developed a novel microneedle-type glucose sensor using polyimide, designated the PI sensor (outer diameter, 0.3 mm; length, 16 mm), and investigated its characteristics in vitro and in vivo. In the in vitro study, we tested the sensor in 0.9% NaCl solution with varying glucose concentrations and observed an excellent linear relationship between the sensor output and glucose concentration (range: 0-500 mg/100 ml). In in vivo experiments, the PI sensor was inserted into the abdominal subcutaneous tissue of beagle dogs (n = 5), and interstitial fluid glucose concentrations were monitored after sensor calibration. Simultaneously, blood glucose concentrations were also monitored continuously with another PI sensor placed intravenously. The correlation and time delay between subcutaneous tissue glucose (Y) and blood glucose concentrations (X: 30-350 mg/100 ml) were Y = 1.03X + 7.98 (r = 0.969) and 6.6 +/- 1.2 min, respectively. We applied the new WAEP system/PI sensor and an intravenous insulin infusion algorithm developed previously for glycemic control in diabetic dogs. The use of the WAEP system resulted in excellent glycemic control after an oral glucose challenge of 1.5 g/kg (post-challenge blood glucose levels: 176 +/- 18 mg/100 ml at 65 min and 93 +/- 23 mg/100 ml at 240 min), without any hypoglycemia. Thus, we confirmed that our new PI sensor has excellent sensor characteristics in vitro and in vivo. The new WAEP using this sensor is potentially suitable for clinical application.

Comparison between closed-loop portal and peripheral venous insulin delivery systems for an artificial endocrine pancreas

To establish the ideal insulin delivery route for an artificial endocrine pancreas, we examined the effectiveness of closed-loop portal insulin delivery. We investigated the effects of the route of insulin delivery on net hepatic glucose balance (NHGB) in dogs under pancreatic clamp conditions with somatostatin plus basal glucagon and insulin infusions. A constant rate of suprabasal insulin was infused via the portal vein or a peripheral vein, and glucose was infused into the portal vein for 180 min. The mean net hepatic glucose uptake (NHGU) values in the portal insulin infusion group (PI group) were significantly greater than those in the peripheral venous insulin infusion group (VI group); the changes from the baseline values at 180 min were 3.54 +/- 0.66 and 2.45 +/- 0.82 mg kg(-1) min(-1) in the PI and VI groups, respectively, P < 0.05. Furthermore, dogs under pancreatic clamp conditions were controlled after a 2-g/kg oral glucose load by applying the closed-loop intraportal (PO) or intravenous (IV) insulin infusion algorithm. There were no significant differences in glycemic control and insulin requirements between these algorithms. However, the maximum peripheral venous and arterial plasma insulin concentrations with the PO algorithm were significantly lower than those with the IV algorithm [305.1 +/- 68.9 and 468.1 +/- 66.9 pmol/l (peripheral vein) and 305.3 +/- 62.9 and 469.6 +/- 85.1 pmol/l (artery) with the PO and IV algorithms, respectively, P < 0.05]. On the other hand, the maximum portal plasma insulin concentration with the PO algorithm was significantly higher than that with the IV algorithm (619.9 +/- 101.7 and 414.3 +/- 79.9 pmol/l with the PO and IV algorithms, respectively, P < 0.05). The mean NHGU values with the PO algorithm were significantly greater than those with the IV algorithm. Our results confirmed that closed-loop portal insulin delivery is feasible with regard to both insulin profiles and hepatic glucose handling in vivo, and indicated that the portal vein is the most suitable insulin delivery route for the artificial endocrine pancreas.

Strict glycemic control in diabetic dogs with closed-loop intraperitoneal insulin infusion algorithm designed for an artificial endocrine pancreas

The ultimate goal of the development of an artificial endocrine pancreas is to achieve long-term strict glycemic regulation. To establish the physiological insulin delivery route of the artificial endocrine pancreas, intraperitoneal insulin infusion may be important. For this purpose, we tried to develop a closed-loop intraperitoneal insulin infusion algorithm by analyzing the pharmacokinetics of intraperitoneal regular insulin absorption using a mathematical model. The parameters for this algorithm were calculated to simulate the plasma insulin profile after intraperitoneal insulin injection as closely as possible. To evaluate the appropriateness of this algorithm, we tried glycemic control after an oral glucose load of 2 g/kg or a meal load of 80 kcal/kg in diabetic dogs by applying the algorithm. With the use of the subcutaneous insulin lispro infusion algorithm, which we have previously reported, alloxan-induced diabetic dogs exhibited postprandial hyperglycemia and delayed hyperinsulinemia, followed by hypoglycemia after an oral glucose load of 2 g/kg. However, by using the intraperitoneal insulin infusion algorithm, excellent glycemic control (postprandial blood glucose levels of 9.1 +/- 0.8 mmol/l at 70 min and 3.8 +/- 0.3 mmol/l at 240 min, respectively) could be achieved without any associated delayed hyperinsulinemia or hypoglycemia. Glycemic excursion after a meal load of 80 kcal/kg was also controlled from 3.9 to 10.1 mmol/l. Our results confirm that the intraperitoneal insulin infusion algorithm in vivo is feasible and that this algorithm can be superior to the subcutaneous insulin lispro infusion algorithm in the regulation of blood glucose.

An animal model of cerebral infarction. Homologous blood clot emboli in rats

An experimental model of cerebral infarction is created in rats by intracarotid injection of their homologous blood clots. This is the first small animal model in which embolization was achieved by homologous blood clots. The infarcts were produced predominantly in the territory of the middle cerebral artery. The low mortality rate and excellent reproduction rate make possible the correlative study of morphological, biochemical, and metabolic parameters at selected points in time to reconstruct the pathogenesis and natural history of focal cerebral ischemia and its relation to blood elements.