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Diabetes is a complex disease defined by hyperglycaemia; however, strong associations with abdominal obesity, hypertension and dyslipidaemia contribute to the high risk of cardiovascular disease. Although aggressive glycaemic control reduces microvascular complications, the evidence for macrovascular complications is less certain. The theoretical benefits of the mode of action of peroxisome proliferator-activated receptor (PPAR) agonists are clear. In clinical practice, PPAR- α agonists such as fibrates improve dyslipidaemia, while PPAR- γ agonists such as thiazolidinediones improve insulin resistance and diabetes control. However, although these agents are traditionally classed according to their target, they have different and sometimes conflicting clinical benefit and adverse event profiles. It is speculated that this is because of differing properties and specificities for the PPAR receptors (each of which targets specific genes). This is most obvious in the impact on cardiovascular outcomes-in clinical trials pioglitazone appeared to reduce cardiovascular events, whereas rosiglitazone potentially increased the risk of myocardial infarction. The development of a dual PPAR- α/ γ agonist may prove beneficial in effectively managing glycaemic control and improving dyslipidaemia in patients with type 2 diabetes. Yet, development of agents such as muraglitazar and tesaglitazar has been hindered by various serious adverse events. Aleglitazar, a balanced dual PPAR- α/ γ agonist, is currently the most advanced in clinical development and has shown promising results in phase II clinical trials with beneficial effects on glucose and lipid variables. A phase III study, ALECARDIO, is ongoing and will establish whether improvements in laboratory test profiles translate into an improvement in cardiovascular outcomes. [ABSTRACT FROM AUTHOR]

Aim: Sulphonylureas (SUs) are among the most widely used oral hypoglycaemic drugs that stimulate insulin secretion. In addition, SUs have pleiotropic effects on other tissues. Conflicting findings have been reported regarding the effects of SUs on adipocytes. We have now investigated the actions of glimepiride and glibenclamide (=glyburide) in primary human adipocytes. Methods: Primary cultured human white pre-adipocytes were differentiated in vitro according to a standard protocol. Lipid accumulation was assessed by Oil Red O staining and determination of triglyceride content; gene expression was measured by RT PCR and Western blotting. Results: Initially, we characterized the genes regulated during human pre-adipocyte differentiation by performing global microarray analysis. Treatment with glimepiride and glibenclamide caused an increased accumulation of lipid droplets and triglycerides. In addition, genes involved in lipid metabolism were induced and chemokine expression was decreased. Interestingly, the effects of SUs were generally qualitatively and quantitatively similar to those of pioglitazone. In direct comparison, glibenclamide was more potent than glimepiride with respect to the induction of fatty acid binding protein 4 (FABP4) (EC50 0.32 vs. 2.8 µM), an important adipocyte marker gene. SU-induced differentiation was virtually completely blocked by the peroxisome proliferator-activated receptor γ (PPAR γ)-antagonist T0070907 but not affected by diazoxide, indicating PPAR γ activation by SUs. Repaglinide had no effect on adipogenesis, although it causes insulin liberation like SUs. Conclusions: In primary human pre-adipocytes, glibenclamide and glimepiride strongly induced differentiation, apparently by activating PPAR γ. Thus, SUs but not repaglinide may be used to influence insulin resistance beyond their effect on insulin liberation. [ABSTRACT FROM AUTHOR]

To evaluate the effects of intensive insulin therapy alone and with added pioglitazone on body weight, fat distribution, lean body mass (LBM) and liver fat in type 2 diabetic patients. Twenty-five insulin-treated, obese patients with type 2 diabetes were randomized to addition of pioglitazone 45 mg (n = 12) or placebo (n = 13) and treated intensively for 12-16 weeks. Dual-energy X-ray absorptiometry/abdominal computed tomography scans were performed before/after treatment. LBM, visceral/subcutaneous adipose tissue (VAT/SAT) and liver/spleen (L/S) attenuation ratios were measured pre-/posttreatment (a ratio <1 represents fatty liver). Intensive insulin alone and insulin + pioglitazone significantly improved glycaemic control (7.8 ± 0.3 to 7.2 ± 0.3% and 7.6 ± 0.3 to 7.1 ± 0.4%, respectively). Body weight gain was greater with insulin + pioglitazone (4.9 ± 4.5 kg) versus insulin therapy alone (1.7 ± 0.7 kg). SAT increased significantly with pioglitazone + insulin therapy (393.9 ± 48.5 to 443.2 ± 56.7 cm, p < 0.01) compared to a non-significant increase with insulin therapy alone (412.9 ± 42.5 to 420.8 ± 43.8 cm). VAT decreased non-significantly in both groups (240.3 ± 41.7 to 223.8 ± 38.1 cm with insulin + pioglitazone and 266.6 ± 27.4 to 250.5 ± 22.2 cm with insulin therapy). LBM increased significantly by 1.92 ± 0.74 kg with insulin + pioglitazone treatment. The L/S attenuation ratio in the placebo + insulin group decreased from 1.08 ± 0.1 to 1.04 ± 0.1 (p = ns) and increased from 1.00 ± 0.1 to 1.08 ± 0.05 (p = 0.06) in the pioglitazone + insulin group. Intensification of insulin therapy in type 2 diabetic patients causes modest weight gain and no change in body fat distribution, LBM or liver fat. In contrast, the addition of pioglitazone, at equivalent glycaemia, increases weight gain, fat mass and SAT; increases LBM and tends to decrease liver fat. These changes in fat distribution may contribute to the beneficial effects of pioglitazone, despite greater weight gain. [ABSTRACT FROM AUTHOR]

Endothelial microparticles (EMPs) and endothelial progenitor cells (EPCs) are markers of endothelial injury and repair. We compared the effects of pioglitazone versus metformin on the circulating numbers of EMPs and EPCs in patients with newly diagnosed type 2 diabetes. This was a randomized, double-blind, comparator-controlled, 24-week single-centre trial conducted in a Teaching Hospital in Naples, Italy. One hundred and ten people with newly diagnosed type 2 diabetes who were never treated with antihyperglycaemic drugs and had haemoglobin A1c (HbA1c) levels between 7 and 10% were given pioglitazone hydrochloride (15-45 mg/day) (n = 55) or metformin (1000-2000 mg/day) (n = 55) as an active comparator. Absolute change from baseline to final visit in circulating EMPs and EPCs and their ratio were the main outcomes. Baseline characteristics did not differ between the study groups. The decrease in circulating EMPs CD31+ [intergroup difference, −32 counts/µl (95% CI −51 to −9)] and the increase in EPCs CD34+/KDR+ [intergroup difference, 33 cells/10 events (95% CI 13 to 55)] were greater with pioglitazone versus metformin. EMPs/EPCs ratio was reduced with pioglitazone and unchanged with metformin [difference, −1.5 (95% CI −2.6 to −0.5), p < 0.001]. Participants assigned to pioglitazone gained more weight and experienced greater improvements in some coronary risk measures [high-density lipoprotein (HDL)-cholesterol, triglycerides, adiponectin and C-reactive protein (CRP)] than did those assigned to metformin. Compared with metformin, pioglitazone treatment improved the imbalance between endothelial damage and repair capacity and led to more favourable changes in coronary risk factors in patients with newly diagnosed type 2 diabetes. [ABSTRACT FROM AUTHOR]

We conducted a three-arm, parallel-group, randomized, controlled trial to compare the effects of rosiglitazone and physical exercise on endothelial function in patients with coronary artery disease and impaired fasting glucose or impaired glucose tolerance over a 6-month period. Group A received rosiglitazone tablets 8 mg daily (n = 16), group B underwent a structured physical exercise programme (n = 15) and group C served as a control group (n = 12). At baseline and after 6 months, brachial artery ultrasound imaging was performed to assess reactive flow-mediated dilation (FMD). Rosiglitazone treatment and exercise both led to significant improvements in insulin resistance at 6 months, whereas no change was observed in control patients. FMD improved significantly in physical exercise patients, whereas no change could be observed in patients receiving rosiglitazone or in the control group. Between-group comparisons also showed a significant relative improvement in FMD in exercise patients compared with rosiglitazone. [ABSTRACT FROM AUTHOR]