Effect of pravastatin on erythrocyte rheological and biochemical properties in poorly controlled Type 2 diabetic patients.

AIMS: The rheological properties of erythrocytes are impaired in diabetes mellitus, especially because of changes in their membrane lipid composition. In hypercholesterolaemic patients, lowering plasma cholesterol is associated with an improvement of the erythrocyte rheological parameters. The aim of this study was to investigate the relationship between erythrocyte deformability, plasma lipids, lipid membrane composition and cytosolic cations in poorly controlled Type 2 diabetic patients and to test the effects of a cholesterol-lowering treatment on these parameters. METHODS: We compared 37 poorly controlled Type 2 diabetic patients with 26 controls. In 22 of the diabetic patients who showed an impairment in erythrocyte deformability (filtration index >10.5 on the Hanss' haemorheometer), a double-blind randomized trial compared the effect of the inhibitor of HMG CoA reductase pravastatin 20 mg per day for 4 months vs. placebo on the erythrocyte parameters. RESULTS: Compared with controls, diabetic patients had higher filtration index (FI), erythrocyte sodium and calcium contents and lower free cholesterol-phospholipids ratio in erythrocyte membranes. Erythrocyte sodium content correlated positively with the FI and the membrane free cholesterol-phospholipids ratio. In the pravastatin-treated group (11 patients), fibrinogen decreased significantly, FI reached a normal value (<10) in six patients. Four of the five other patients who still had abnormal FI after 4 months of treatment had either a high plasma triglycerides (> or =4.60 mmol/l) or a high plasma fibrinogen (> or =4 g/l) level at baseline. Only two of the 11 placebo-treated patients achieved a normal FI. CONCLUSION: These data suggest that in poorly controlled Type 2 diabetic patients there is a link between the chemical composition and the rheological properties of erythrocytes. Erythrocyte deformability may be improved by lowering plasma cholesterol with a statin.

[Erythrocyte rheology and heart hypertrophy in diabetes mellitus]. / Rhéologie erythrocytaire et hypertrophie cardiaque au cours du diabète sucré.

Reduced red cell filtration and increased aggregation have been reported in diabetic patients. Heart enlargement is a classical complication of high blood pressure but is also frequently encountered in diabetics. The aim of this work was to explore the relationship between rheological disorders and heart enlargement in diabetics and in an animal model of genetically diabetic rats. 1. Among a series of 92 patients with insulin-dependent or non-insulin-dependent diabetes mellitus, silent myocardial ischemia was evidenced in 28. Coronarography in 24 of these patients was strictly normal in 15. In the patients with angiographically normal coronary arteries, the coronary reserve was perturbed by intracoronary injection of papaverine. The left ventricular mass was normal in 79 patients. In patients with silent myocardial ischemia and angiographically normal coronary arteries, there was a positive correlation between left ventricular mass and red cell filtration index using the Hanss hemorheometer (n = 8, r = 0.954, p = 0.001). 2. Red cell stiffness was studied sequentially from 3 to 18 months in diabetic rats Goto Kakisaki (GK). In these rats, cardiac index (heart weight/body weight) was significantly higher than that in Wistors control rats (0.27 +/- 0.02% vs. 0.17 +/- 0.01%, p < 0.001) and was significantly correlated with erythrocyte magnesium (r = 0.920, p 0.026). Overall, the cardiac index in the rats was significantly correlated with red cell filtration (r = 0.370, p = 0.044). In GK rats, heart rate was significantly slower and systolic blood pressure was slightly higher than in control rats (telemetric measures). These findings show that in diabetes mellitus, heart enlargement may be determined by factors other than hypertension or sensitivity to sympathetic stimulation and might be favored by rheological changes and/or excessive intracellular magnesium. In patients with diabetes, the reduced coronary reserve could result in left ventricular hypertrophy but also rheological changes.