Increased plasma concentrations of lipoprotein(a) for every phenotype of apolipoprotein(a) in patients with chronic renal failure treated by hemodialysis

Background and Aims: Uremic patients on hemodialysis show high levels of lipoprotein(a) [Lp(a)]. Whereas in Japanese and Spanish hemodialysis patients high Lp(a) levels have been found for every apo(a) phenotype, in Austrian hemodialysis patients two studies showed an apo(a) phenotype-associated elevation of Lp(a) concentration In this investigation we studied the influence of apo(a) genetic polymorphism on Lp(a) concentrations in a large group of Italian patients with chronic renal failure on hemodialysis. Methods and Results: Lp(a) levels were about three times higher in patients (n=138) than in controls (n=148): 27.7 mg/dl (2.5-131) vs 10.0 mg/dl (0-64.5); p<0.001. In hemodialysis patients Lp(a) plasma concentrations were increased for every apo(a) isoform. The Lp(a) elevation was present in both patients with apo(a) isoforms of high Molecular Weight (MW) and those with apo(a) isoforms of low MW. In addition, the linear interpolation curve, which correlates each apo(a) isoform MW with the corresponding median of Lp(a) levels, in patients is shifted toward higher Lp(a) values compared with that of the controls. Conclusions: Our results indicate that in Italian patients on hemodialysis the elevation of Lp(a) involves every apo(a) phenotype. This finding suggests that the cardiovascular risk related to Lp(a) concentration might be increased in all hemodialysis patients. Moreover, we found that Lp(a) levels were not related to hemodialysis duration. Therefore, the unselective increase in Lp(a) might be the consequence of chronic renal failure. In conclusion although apo(a) phenotypes influence Lp(a) concentration, increased Lp(a) levels in hemodialysis are related in part to other non-generic factors, such as chronic renal failure. (C) 1996, Medikal Press