Can a selective PPARγ modulator improve glycemic control in patients with type 2 diabetes with fewer side effects compared with pioglitazone?

OBJECTIVE: INT131 besylate is a potent, nonthiazolidinedione, selective peroxisome proliferator-activated receptor γ (PPARγ) modulator (SPPARM) designed to improve glucose metabolism while minimizing the side effects of full PPARγ agonists. This placebo-controlled study compared the efficacy and side effects of INT131 besylate versus 45 mg pioglitazone HCl in subjects with type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS: This was a 24-week randomized, double-blind, placebo- and active-controlled study of 0.5-3.0 mg INT131 versus 45 mg pioglitazone or placebo daily in 367 subjects with T2D on sulfonylurea or sulfonylurea plus metformin. The primary efficacy analysis was the comparison of change from baseline to week 24 in hemoglobin A1c (HbA1c) across treatment groups. Fluid status was assessed with a prospective scoring system for lower-extremity pitting edema. RESULTS: INT131 had a steep dose response for efficacy as measured by changes in HbA1c. After 24 weeks' treatment, the 0.5-mg dose demonstrated minimal efficacy (HbA1c -0.3 ± 0.12%) and the 2-mg dose demonstrated near-maximal efficacy (HbA1c -1.1 ± 0.12%), which was not statistically different from the efficacy of 45 mg pioglitazone (HbA1c -0.9 ± 0.12%; P < 0.01 for noninferiority). With the 1-mg dose, INT131 provided significant improvements in glycemic control (HbA1c 0.8 ± 0.12; P < 0.001 vs. placebo) but with less edema, weight gain, and hemodilution than observed with 45 mg pioglitazone. CONCLUSIONS: INT131 demonstrated dose-dependent reductions in HbA1c, equivalent to 45 mg pioglitazone, but with less fluid accumulation and weight gain, consistent with its SPPARM design.

Influence of upper and lower body adipose tissue on insulin sensitivity in South Asian men.

BACKGROUND: South Asians have a high prevalence of insulin resistance, which predisposes to type 2 diabetes. RATIONALE: In the current study, we examined whether insulin sensitivity in South Asian men and men of European descent (Europids) relates to truncal and lower body fat, number of adipocytes, and cell size distribution. RESULTS: Fifteen South Asian men and 15 Europid young men with comparable body mass indexes completed assessments of insulin sensitivity, body composition analysis by dual-energy x-ray absorptiometry, and measurement of adipocyte cellularity in the subcutaneous abdominal (truncal) and gluteal (lower body) adipose tissue. The South Asians and the Europids had similar total body fat and fat contents in truncal and lower body regions. Compared to the Europids, the South Asians had a greater insulin resistance shown by fasting insulin, area-under-the-curve for postprandial insulin, oral glucose insulin sensitivity, homeostatic model assessment of insulin resistance, ß-cell index, and triglyceride-to-high-density lipoprotein ratio. The South Asians had similar number of adipocytes to the Europids, but the South Asians had significantly higher ratios of small-to-larger adipocytes. The South Asians further had a higher fraction of very large adipocytes. In both South Asians and Europids, truncal fat was positively associated with insulin resistance. In the South Asians but not in the Europids, lower body fat was associated with severity of insulin resistance. CONCLUSIONS: The results suggest first, a higher ratio of small-to-larger adipocytes in the South Asians consistent with a lesser lipid storage capacity of adipose tissue; and second, the positive association of lower body fat with insulin resistance in the South Asians implies that fat in their lower body worsens insulin resistance. This association was not observed in the Europids.

U500 regular insulin use in insulin-resistant type 2 diabetic veteran patients.

OBJECTIVE: To evaluate the use of U500 regular insulin therapy in insulin-resistant patients with type 2 diabetes mellitus who were previously treated with high-dosage U100 insulin regimens. METHODS: At a large Veterans Affairs medical center, a retrospective chart review was performed of all patients whose U100 insulin regimens were converted to U500 regular insulin regimens using a protocol to ensure patient safety. Patients were followed up for longer than 6 months. Data reviewed included total daily dosage of insulin before and after regimen conversion and changes in hemoglobin A1c, body weight, lipids, and episodes of severe hypoglycemia. RESULTS: Fifty-three patients met inclusion criteria. Average hemoglobin A1c level on U100 insulin regimens was 9.1 ± 1.7%, which decreased to 8.1 ± 1.3% (P<.001) after an average of 20 months (range, 6-52 months) on U500 insulin. The total daily insulin dosage at study end was not significantly greater on U500 (415 ± 166 units/day) than on U100 insulin (391 ± 120 units/day) (P = .34). Body weight did not change significantly (134 ± 29 kg vs 136 ± 30 kg, P = .18). There was a 20-mg/dL decrease in total cholesterol (P = .014). Triglyceride values decreased by 97 mg/dL (P = .005). Eight episodes of severe hypoglycemia were documented in patients treated with U500 insulin, but this was similar to the incidence in these same patients while treated with U100 insulin. CONCLUSION: We conclude that U500 insulin can be safely and effectively used in insulin-resistant patients with type 2 diabetes followed up at a large Veterans Affairs medical center using a protocol that ensures patients are thoroughly educated and carefully monitored.

Effect of colesevelam hydrochloride on glycemia and insulin sensitivity in men with the metabolic syndrome.

Colesevelam hydrochloride (colesevelam) lowers low-density lipoprotein (LDL) cholesterol and glycated hemoglobin in patients with type 2 diabetes mellitus. The present study examined the effects of colesevelam treatment in nondiabetic men with metabolic syndrome. Twenty men completed the study, which consisted of two 8-week phases of treatment with colesevelam (3.75 g/day) or placebo and a 6-week washout between study phases. Of the 20 men, 17 took statins throughout. The fasting plasma LDL cholesterol, triglyceride, glucose, and glycated hemoglobin levels were measured in the last 2 weeks of each study phase. Nonesterified fatty acids and 3-hydroxybutyrate, insulin, and glucose were measured hourly for 5 hours during fasting and during an extended glucose tolerance test. The colesevelam treatment reduced LDL cholesterol from 96 ± 28 mg/dl to 78 ± 32 mg/dl (p <0.006) and non-high-density lipoprotein cholesterol by 8.2% (p = 0.07). Triglycerides increased by 17% (p <0.02). The fasting plasma glucose was reduced by 5 mg/dl (p <0.03), and glycated hemoglobin remained unchanged by colesevelam. No significant treatment changes were noted for the 2-hour glucose test or insulin sensitivity. The fasting nonesterified fatty acid level was significantly reduced with treatment but the 3-hydroxybutyrate level was unchanged. Insulin-mediated suppression of nonesterified fatty acids during extended glucose tolerance test was significantly less effective during treatment than during placebo. In conclusion, colesevelam significantly reduced the LDL cholesterol levels, even though the baseline LDL cholesterol level was low owing to statin treatment. The fasting and postprandial blood glucose level but not the glycated hemoglobin level was lowered by colesevelam therapy. The effect on fasting glucose was unrelated to the changes in insulin resistance or fatty acid oxidation. Finally, an increase in triglycerides with colesevelam therapy might have been related to a lesser suppression of nonesterified fatty acids levels in the postprandial state.

Selective modulation of PPARγ activity can lower plasma glucose without typical thiazolidinedione side-effects in patients with Type 2 diabetes.

OBJECTIVE: INT131 besylate is a potent non-thiazolidinedione selective peroxisome proliferator-activated receptor γ (PPARγ) modulator (SPPARM) designed to improve insulin sensitivity and glucose metabolism while minimizing the side effects of full agonist thiazolidinediones. This study was conducted to determine short-term efficacy and safety of INT131 besylate in patients with Type 2 diabetes mellitus (T2DM). RESEARCH DESIGN AND METHODS: This was a 4-week randomized, double-blind, placebo-controlled multi-center study with 1 or 10mg INT131 besylate or placebo daily in subjects with T2DM not receiving pharmacotherapy for their hyperglycemia. The primary efficacy analysis was the comparison of treatment groups with respect to least square mean change from baseline to Week 4 of fasting plasma glucose (FPG). RESULTS: Baseline mean (± S.D.) FPG for the study population was 171 ± 42 mg/dl. Change in FPG (± S.E., mg/dl) from baseline after 4 weeks was 8 ± 8 (P=NS) with placebo, -22 ± 8 with 1mg INT131 besylate (P=.0056) and -46 ± 7 with 10mg INT131 besylate (P<.0001). Modeling of available data from the literature of the effect of rosiglitazone under similar study conditions suggested that 1 mg of INT131 besylate had a similar reduction in FPG as expected with 8 mg of rosiglitazone. INT131 besylate was well tolerated, and the 1 mg dose demonstrated no evidence of fluid retention or weight gain. CONCLUSIONS: INT131 besylate demonstrated a dose dependent reduction in FPG. The FPG reduction with 1mg INT131 besylate was comparable to the modeled 8 mg dose of rosiglitazone, and did not cause fluid retention or weight gain. These results are consistent with the INT131 SPPARM design.

Management of dyslipidemia in people with type 2 diabetes mellitus.

Cardiovascular disease is a major complication of type 2 diabetes mellitus, and this is partly due to associated abnormalities of plasma lipid and lipoprotein metabolism. Although glycemic control improves plasma lipoprotein abnormalities and may have an independent benefit on cardiovascular risk reduction, the magnitude of this benefit is less than cholesterol lowering therapy. Current treatment guidelines for the management of dyslipidemia in people with type 2 diabetes are based on the results of cardiovascular outcome clinical trials. Primary emphasis of treatment should be on lowering LDL-C to < 100 mg/dl with statins. If cardiovascular disease is present, then high dose statins should be used, and an optional LDL-C goal < 70 is recommended. If triglycerides are > 200 mg/dl, then a secondary goal is to lower non-HDL-C < 130 mg/dl (< 100 mg/dl if cardiovascular disease is present) is recommended. Low HDL-C levels are common in type 2 diabetes but are not currently recommended as a target for treatment because of the lack of definitive cardiovascular outcome studies supporting this goal, and because of the difficulty in raising HDL-C. The additional benefit of combination therapy with fibrates, ezetimibe or niacin added to a statin on cardiovascular risk is uncertain pending the results of on-going cardiovascular outcome studies.

Impaired hepatic ketogenesis in moderately obese men with hypertriglyceridemia.

BACKGROUND: Several studies suggest that increased nonesterified fatty acid flux and increased de novo lipogenesis may contribute to hypertriglyceridemia, but few studies have examined fatty acid oxidation as a factor. RATIONALE: Endogenous hypertriglyceridemia (increased very low density lipoprotein triglyceride) could result from (a) re-esterification of excess nonesterified fatty acids entering the liver, (b) activation of hepatic lipogenesis, and/or (c) defective oxidation of hepatic fatty acids leading to greater triglyceride synthesis. Therefore, this study used plasma levels of 3-hydroxybutyrate as a marker for fatty acid oxidation. The study was carried out in hypertriglyceridemic and normotriglyceridemic subjects under 3 conditions: (a) in the fasting state, (b) after a fatty meal that should enhance fatty acid oxidation, and (c) after an oxandrolone challenge, which we recently showed increases fatty acid oxidation. RESULTS: In the fasting state, 3-hydroxybutyrate concentrations in hypertriglyceridemic patients were only 53% of levels in normotriglyceridemic subjects. After a fatty meal, moderate increases in 3-hydroxybutyrate were observed, but values for patients with hypertriglceridemia remained 62% of the levels in the normotriglyceridemic group. A similar pattern of response was observed with oxandrolone challenge. There were no significant changes in fasting or postprandial levels of nonesterfified fatty acids, glycerol, or triglycerides before and during the oxandrolone challenge. CONCLUSION: Patients with endogenous hypertriglyceridemia seem to have a defect in fatty acid oxidation as indicated by reduced levels of 3-hydroxybutyrate. This defect was observed during fasting, postprandially, and during oxandrolone challenge. We propose that this defect contributes to the development of hypertriglyceridemia.

Oxandrolone enhances hepatic ketogenesis in adult men.

BACKGROUND: Immediate administration of oxandrolone markedly increases hepatic lipase activity and reduces levels of plasma high-density lipoprotein. RATIONALE FOR THE STUDY: We postulated that oxandrolone should increase hepatic lipase and that the nonesterified fatty acids generated would enhance hepatic ketogenesis during an extended fat tolerance test. MAIN RESULTS: Eighteen men participated in the study using short-term administration of oxandrolone (10 mg/d) over a week. Subjects had evaluation of hepatic ketogenesis at baseline and after 7 days of administration of oxandrolone. Ketogenesis was assessed by measuring plasma levels of 3-hydroxybutyrate during a fat tolerance test. Oxandrolone increased fasting levels of 3-hydroxybutyrate by 70%, and increased the area under the curve during an FFT by 53% above pretreatment levels without affecting the areas under the curve for nonesterified fatty acids, glycerol, or triglycerides. Fasting 3-hydroxybutyrate levels correlated with nonesterified fatty acids and with triglycerides; however, there were no significant correlations with any other parameter. CONCLUSIONS: This study shows that short-term administration of oxandrolone results in marked increases in hepatic ketogenesis. This finding is consistent with an increased influx of fatty acids into the liver secondary to lipoprotein lipolysis by increased hepatic lipase. However, the possibility cannot be ruled out that oxandrolone acts directly in the liver to stimulate fatty acid oxidation. Therefore, the observation of increased ketogenesis will require further studies to determine the molecular basis of the response.