ACUTE CHANGES IN CONCENTRATIONS OF APOLIPOPROTEIN-A-I, APOLIPOPROTEIN-B, APOLIPOPROTEIN-C-II AND LIPOPROTEIN(A) IN SERUM COVERING THE PERIOD FROM DIRECTLY BEFORE TO 48 HOURS AFTER CHRONIC-HEMODIALYSIS

This study reports the changes in total cholesterol, triacylglycerols, apolipoproteins A-I, B, C-II and (a) before, directly after and 48 ho urs after chronic renal dialysis on 46 non-selected patients (20 male, 26 female; time since first dialysis 1-203 months (median 22 months), median age 52 years, range 25-82 years). Thirty six of the 46 patient s (17 men and 19 women) suffered from hypertension. There were no sex- linked differences in any analyte except cholesterol, which was signif icantly higher in women than in men at all times. The apolipoproteins were determined with immunoluminometric assays. Apolipoprotein C-II wa s determined as the apolipoprotein C-II : apolipoprotein B complex. Li poprotein(a) was determined using two antibodies directed against apol ipoprotein(a). Significant increases (p < 0.05) in serum concentration s before and after dialysis were seen for all analytes with the except ion of cholesterol (no significant change) and apolipoprotein C-II (si gnificant decrease). The median increases were: cholesterol 5%, triacy lglycerols 28%, apolipoprotein A-I 19%, apolipoprotein B 11%, apolipop rotein C-II -39%, lipoprotein(a) [all patients 21%, < 300 mg/l 8%, > 3 00 mg/l 163%]. The values 48 hours after dialysis were not significant ly different from the value before dialysis for cholesterol (-5%), apo lipoprotein B (0%) and lipoprotein(a) (-2% - all patients). Statistica lly significant lower concentrations of apolipoprotein C-II (-28%) (p < 0.01) and triacylglycerols (-19%) (p < 0.01) were observed, but not investigated further. The behaviour of lipoprotein(a) was not correlat ed with any of the other analytes except triacylglycerols, where a sta tistically significant negative correlation was seen in all groups. Ap olipoprotein B and apolipoprotein C-II, triacylglycerols and apolipopr otein C-II, and apolipoprotein B and triacylglycerol concentrations we re correlated at all three sampling times. Lipoprotein(a) correlated w ith cholesterol only directly after dialysis, whereas cholesterol and triacylglycerols correlated before and 48 hours after dialysis, but no t directly after dialysis. None of the analytes correlated with the ti me since the first dialysis, i. e. with the length of time on dialysis . The results showed that dialysis by no means had a uniform effect on the lipid analytes studied, and that those patients with elevated lip oprotein(a) were subject to elevations of this analyte directly after dialysis, which were on average more than three times those before dia lysis. The clinical relevance of these findings must be investigated f urther. The results indicate that it is important to standardise the b lood sampling time for dialysis patients as results obtained before, d uring, and immediately after dialysis may vary significantly.