PROTEIN LOSS AND GENETIC-POLYMORPHISM OF APOLIPOPROTEIN(A) MODULATE SERUM LIPOPROTEIN(A) IN CAPD PATIENTS

Lipoprotein(a) (Lp(a)) serum concentrations and apoprotein(a) isoforms were measured in 64 uraemic patients treated with continuous ambulato ry peritoneal dialysis (CAPD) and compared with those in 155 normal co ntrols. The mean Lp(a) values were 44 +/- 5 mg/dl (median 30 mg/dl) in CAPD patients and 22 +/- 3 mg/dl (9 mg/dl) in controls (P<0.01). With in the most common apo(a) isoform classes, higher concentrations of Lp (a) were seen in the CAPD patients compared with the controls (P<0.05) . These results were not influenced by differences in the frequency di stribution of the apo(a) isoforms. Twenty-six CAPD patients (41%) were suffering from coronary artery disease and 63% of these patients exhi bited low-molecular-weight isoforms less than or equal to S2, compared with 31% of the patients without coronary artery disease. Furthermore a positive correlation between the daily protein (r=0.4, P=0.02) and albumin loss (r=0.39, P=0.2) into the dialysis fluid and the Lp(a) ser um concentration was also observed. Therefore we suggest that the elev ated Lp(a) concentrations in CAPD patients are influenced by the amoun t of protein loss into the dialysate and by the allelic variation of t he apo(a) isoform. In addition to the typical dyslipidaemia found in C APD patients, high levels of Lp(a) and specific isoform patterns may i n turn contribute to the elevated risk of coronary artery disease and other cardiovascular complications.