Apolipoprotein C-III, hypertriglyceridemia and triglyceride-rich lipoproteins in uremia

Apolipoprotein C-III (ApoC-III) plays an important role in the metabolism o f triglyceride-rich lipoproteins and is known to be elevated in patients wi th uremia. To investigate the role of apoC-III in uremic dyslipidemia, we e xamined apoC-III, triglyceride levels and lipoprotein particles containing both apoB and apoC-III (LP-Bc) in 27 uremic patients prior to dialysis (pre dialysis), 30 patients on hemodialysis (HD) and 31 patients on peritoneal d ialysis (PD). All three groups of patients had elevated levels of plasma ap oC-III (20+/-7 mg/dl for predialysis, 18+/-5 for HD and 22+/-8 for PD, comp ared to 11+/-3 mg/dl for control subjects [p<0/01 for all comparisons]). Ap oC-III was positively correlated with plasma triglycerides in PD patients ( r=0.86, p<0.0001), HD patients (r=0.67, p<0.0001) and predialysis patients (r=0.60, p<0.001) as well as in all patients combined (r=0.75, p<0.0001). A poC-III was also positively correlated with levels of LP-Bc in all three gr oups of patients, although this correlation was less strong (r=0.46, p<0.00 01 for all patients combined). In predialysis and PD patients, the majority of apoC-III was found in heparin precipitable lipoproteins, whereas the ma jority of apoC-III in HD patients was found in HDL, indicating less efficie nt lipolysis in predialysis and PD patients in comparison with HD. These da ta support the hypothesis that the elevation of apoC-III in uremia can alte r the metabolism of triglyceride-rich lipoproteins, leading to an elevation in triglycerides and LP-Bc. Understanding the mechanism(s) of elevated apo C-III in uremia may help to clarify the causes of uremic dyslipidemia. Copy right (C) 2000 S. Karger AG, Basel.