Apolipoprotein(a) phenotypes and lipoprotein(a) concentrations in patientswith renal failure

Patients with renal failure have an increased incidence of atherosclerotic disease. Numerous studies have shown that these patients show increased ser um lipoprotein(a) [Lp(a)] concentrations compared with the control populati on. However, variable alleles at the apolipoprotein(a) [apo(a)] gene locus determine to a large extent the Lp(a) concentration in the general populati on. We therefore undertook the present study to evaluate apo(a) phenotypes and Lp(a) serum concentrations in a large number of patients with renal dis ease. Seventy-nine patients treated by hemodialysis (HD), 47 patients treat ed by continuous ambulatory peritoneal dialysis (CAPD), 68 patients with mi ld/moderate chronic renal failure (CRF) and serum creatinine levels of 1.8 to 8 mg/dL, and 73 healthy controls were studied. All patients showed signi ficantly elevated median serum Lp(a) concentrations in comparison with cont rols: HD patients, 15.7 mg/dL (P < 0.01); CAPD patients, 20 mg/dL (P < 0.00 5); CRF patients, 15.1 mg/dL (P < 0.01) versus controls, 7 mg/dL. The great er Lp(a) values in all groups were not explained by differences in isoform frequencies, whereas their increase was apo(a)-type specific. Thus, patient s in all groups with high-molecular weight (HMW) apo(a) isoforms showed a s ignificant elevation of Lp(a) levels, whereas serum Lp(a) concentrations in patients with low-molecular-weight (LMW) isoforms were not significantly d ifferent from controls, except for CAPD patients, who presented increased s erum Lp(a) concentrations. We conclude that in patients with renal failure, even of mild/moderate degree, as well as in patients with end-stage renal disease undergoing HD or CAPD, elevated Lp(a) concentrations are mainly obs erved in those with HMW apo(a) phenotypes. (C) 1999 by the National Kidney Foundation, Inc.