HDL subfractions distribution in renal transplant recipients: Lack of evidence of a reduction of HDL2 particles

Since the high rate of cardiovascular disease in renal transplant recipients, alterations of lipoprotein profile in such patients were extensively evaluated, but the HDL subclass profile was not completely clarified. Renal transplant recipients usually show normal to high plasma levels of HDL cholesterol, even if some investigations suggested a persistence of low HDL2 levels: this was not useful in terms of cardiovascular protection. We designed this study in order to evaluate HDL subfractions distribution in renal transplant recipients. We studied 55 renal transplant recipients, treated with prednisone, azathioprine and/or cyclosporine, and 34 healthy normolipidemics as controls. In all subjects cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, apolipoproteins A-I and B levels and HDL subfractions, as determined by nondenaturing polyacrylamide gradient gel electrophoresis, were assayed. Renal transplant recipients had cholesterol, triglycerides, LDL cholesterol and apolipoproteins A-I and B levels significantly higher than controls; HDL cholesterol levels were slightly, but not significantly, increased in comparison with controls (respectively 51.1 ± 15.5 and 46.1 ± 10.8 mg/dl). Multivariate analysis showed that only the time since transplantation was significantly associated with HDL cholesterol levels. When HDL subfractions were analyzed, renal transplant recipients presented significantly lower levels of HDL(3a), and HDL(3b) and, in males, higher levels of HDL(2b) than controls. HDL cholesterol levels were positively correlated with HDL(2b) levels in both renal transplant recipients and controls, and negatively correlated with HDL(3b) in controls. In conclusion, in renal transplant recipients, we failed to demonstrate any decrease of HDL2 particles. On the basis of a nonatherogenic HDL profile, we suggest that the increased cardiovascular risk in renal transplant recipients might be accounted for by other risk factors.