Inhibition of lipoprotein lipase by uremic plasma, a possible cause of hypertriglyceridemia.

In an attempt to define pathogenesis of the previously described impaired triglyceride (TG) removal in uremia, the effects of the addition of normal and uremic plasma on the activity of lipoprotein lipase (LPL) from rat epididymal adipose tissue were examined. Six uremic patients on chronic dialysis and 13 normals were studied. Adding increments of normal and uremic plasma increased the LPL activity to maximal levels when 0.1 ml of plasma was added. Larger aliquots of uremic plasma produced marked inhibition of LPL activity. This inhibition was not observed with the normal plasma. When increasing amounts of uremic plasma were added to an incubation mixture already maximally activated by 0.1 ml of normal plasma, inhibition of LPL was again observed. This inhibition was still present in uremic plasma which had been dialysed against cold saline. The inhibitor was in the lipoprotein-free (d greater than 1.225) fraction of the plasma. The results indicate that uremic plasma has an LPL inhibitor which is probably a protein and may play a role in the pathogenesis of uremic hypertriglyceridemia.