Apolipoprotein, C-reactive protein and oxidative stress parameters in dyslipidemic type 2 diabetic patients treated...

Oxidative stress is considered an important factor in the development of diabetic complications that causes a variety of changes such as oxidative modification of membrane lipids, nucleic acids and cellular proteins. Dyslipidemia is frequently associated with diabetes and cardiovascular disease. In this context, the objective of this study was to evaluate oxidative modifications of plasma proteins and lipids in non dyslipidemic type 2 diabetic (T2D) patients, in dyslipidemic T2D patients treated or not with simvastatin and in healthy subjects to investigate whether treatment with low doses of simvastatin plays a protective role on the lipid and protein oxidative damage in these patients.

We determined oxidative damage of plasma proteins by carbonyl assay and total thiol group determination. We also characterized the membrane damage in terms of lipid peroxidation by measuring malonaldehyde (MDA) in nondyslipidemic T2D patients, dyslipidemic T2D patients treated with simvastatin (20 mg/day), dyslipidemic T2D patients not treated with simvastatin and in healthy age-matched control subjects.

Our results showed that dyslipidemic T2D patients not treated with simvastatin had significantly higher plasma protein carbonyl groups and MDA when compared to dyslipidemic T2D patients treated with simvastatin and control group. Thiol concentrations from dyslipidemic T2D patients not treated with simvastatin were significantly lower than treated patients and controls. It was verified that the thiols groups were inversely correlated with apolipoprotein B and positively correlated with apolipoprotein A-I.

These results demonstrated that treatment with low doses of simvastatin can minimize the protein and lipid oxidative damage in dyslipidemic T2D patients.