Lipoprotein metabolism in normal and uremic patients

Abnormalities in circulating lipoprotein concentrations are a characteristic finding both in patients with uremia and in patients undergoing dialysis. These patients tend to have elevated triglyceride (TG) concentrations and low concentrations of high-density lipoprotein (HDL) cholesterol. Elevations of low-density lipoprotein (LDL) are not usually observed unless the patients have undergone renal transplantation and are receiving therapy with immune suppressive medications. Hypertriglyceridemia and low HDL may be the consequence of decreased actions of lipoprotein lipase (LPL), the endothelial cell-bound enzyme that degrades circulating lipoprotein triglyceride. A poorly characterized circulating inhibitor to this enzyme is found in uremic plasma. Preliminary data suggest that high-flux dialysis with polysulfone (PS) membranes improves the lipoprotein abnormalities and decreases circulating LPL inhibitors. Whether such therapy will alter the incidence of coronary morbidity and mortality in patients with end-stage renal failure remains to be tested.