• Action of glitazone on the endothelium-dependent vasodilatory effects of HDL lipoproteins [ Time Frame: 6 months ] [ Designated as safety issue: No ]
  

• Effect of glitazone therapy on Phospholipase A2 level [ Time Frame: 6 months ] [ Designated as safety issue: No ]
  
• Analyze the glycemic response to glitazones according to baseline clinical and biological characteristics [ Time Frame: 6 months ] [ Designated as safety issue: No ]
  
• Look for possible differences between pioglitazone and rosiglitazone for their effects on HDL lipoproteins and phospholipase A2 [ Time Frame: 6 months ] [ Designated as safety issue: No ]
  

The study will be performed as follows:

At baseline, before initiating glitazone treatment, clinical data will be recorded and blood samples will be obtained for biological measurements (blood glucose, HbA1c, total cholesterol, triglycerides, LDL-cholesterol, HDL-cholesterol, liver enzymes), phospholipase A2 measurement and the study of the vasodilatory effect of HDL particles.For this purpose, we will study,using rabbit aorta rings,the ability of HDL to suppress the inhibition of vasodilation that is induced by oxidised LDL.

For all the patients included into the study, a treatment by pioglitazone (at an initial dose of 30 mg/day) or rosiglitazone (at an initial dose of 4 mg/day) will be given by randomization.

A visit will be performed at week 12, in order to titrate the glitazone dose (up to 45 mg/day for pioglitazone, up to 8 mg/day for rosiglitazone)according to HbA1c level and values of self-monitoring blood glucose.

At week 24, the last visit will take place. During this visit, clinical data will be recorded and blood samples will be obtained for biological measurements (blood glucose, HbA1c, total cholesterol, triglycerides, LDL-cholesterol, HDL-cholesterol, liver enzymes), phospholipase A2 measurement and the study of the vasodilatory effect of HDL particles.