Pathogenic roles of post-heparin lipases in lipid abnormalities in hemodialysis patients.

The relative roles of hepatic lipase and lipoprotein lipase in the pathogenesis of uremic lipid abnormalities were studied in 92 hemodialysis patients. Fasting serum cholesterol, triglyceride, and HDL-cholesterol concentrations were measured. Plasma lipoprotein electrophoretic patterns were determined in all patients. Hepatic lipase and lipoprotein lipase activities were selectively measured in post-heparin plasma in 59 patients. Hemodialysis patients had higher serum triglyceride and lower HDL-cholesterol concentrations than did their age and sex-matched control subjects. Both hepatic and lipoprotein lipase activities were reduced in hemodialysis patients. An inverse relation between lipoprotein lipase activities and serum triglyceride concentrations emerged. Lipoprotein lipase activities correlated with in vivo post-heparin fractional clearance rates of Intralipid. A positive correlation between lipoprotein lipase activities and HDL-cholesterol concentrations probably reflected impaired catabolism of triglyceride-rich lipoproteins being responsible for the low HDL-cholesterol concentrations. Hemodialysis patients (41.3%) had an abnormal lipoprotein (the 'mid-band'). While hepatic lipase activities did not correlate with any parameters of lipid metabolism, patients with 'low' hepatic lipase activities had a significantly higher prevalence of 'mid-bands' than did those with 'normal' activities. No evidence was developed to prove that the 'mid-band' lipoproteins were remnant particles.