Alteration of the lipid and apolipoprotein contents of lipoprotein(a) in haemodialysis patients

Background. To examine the possible alteration in Lp(a) composition, protein and lipid contents of Lp (a) were determined in 10 haemodialysis patients (HD) matched with 10 controls (C) for apo(a) phenotypes. Methods. All subjects (HD and C) had Lp(a) concentrations greater than 30 mg/dl (mean +/- SD : 82.3 +/- 41.4 vs 49.3 +/- 22.5 mg/dl), a concentration which has been determined to be associated with an elevated cardiovascular risk. Apo(a)-containing particles were isolated by immunoaffinity chromatography using a monoclonal anti-apo(a) antibody. Results. The molar concentrations of lipid and protein constituents of immunoaffinity isolated Lp(a) were expressed as number of moles per mole of apo(a). Lp(a) from HD patients were significantly richer in apo C111 (P<0.05) and triglycerides (TG) (P<0.05), compared to those of controls. Molar ratios of apo B, apo E, cholesterol and phospholipids per apo(a)-containing particles were in the same range in both groups. Conclusion. Lp(a) from HD patients is characterized by an elevated content in TG and apo C111 in comparison with those of controls. Further studies are needed to evaluate in HD patients the contribution of changes in Lp(a) composition towards the metabolism of these particles.