Serum lipid abnormalities in heart transplant recipients: predominance of HDL 2-like particles in the HDL pattern

Abstract

Accelerated coronary atherosclerosis is a major risk limiting long-term survival after heart transplantation and is commonly associated with dyslipoproteinemia even in subjects who were not dyslipoproteinemic before intervention. The purpose of this study was to analyse the abnormalities in the lipid profiles of 2 different groups of heart-transplanted males: 18 subjects with underlying ischemic heart disease (IHD) and 19 subjects with non-obstructive cardiomyopathy of unknown aetiology (CM). Both groups were ompared to 33 healthy males. All patients were under immunosuppressive therapy including prednisone, cyclosporin A and azathioprine. A moderate hyperlipidemia was found in all transplant recipients, associated with high HDL-cholesterol concentrations in the CM group (1.80 ± 0.37 vs. 1.29 ± 0.23 mmol/1) and normal HDL-cholesterol levels in the IHD group (1.40 ± 023 mmol/1). HDL subfractionation showed a marked increase in HDL,-cholesterol (CM: 1.12 ± 0.32; IHD: 0.69 ± 0.28; control: 0.40 ± 0.17 mmol/1) while HDL,-cholesterol was significantly lower than in the control group. Analysis of HDL particle sizes showed in all transplant subjects an increase of an intermediate size particle HDL 2a (diameter 9.0 ± 0.10 nm) which is a minor form in control subjects. In the CM group, both the common HDL 2b(10.2 ± 0.13 nm) and HDL 2a were abundant in 13 of 17 patients. The pattern was more heterogeneous in the IHD group but witnessed to a high frequency of HDL 2a particles either alone ( 5 14 ) or associated with larger HDL 2b( 4 14 ) or with small HDL 3 ( 4 14 ). The coexistence in transplant patients of a high incidence of atherosclerosis with high concentrations of HDL, is in apparent disagreement with the well established negative correlation between these 2 parameters. This suggests that the increase in HDL concentration is possibly due to pharmacological mechanisms involving the immunosuppressive drugs.