Plasma exchange and low density lipoprotein apheresis in Watanabe heritable hyperlipidemic rabbits.

Comparison of the effects of plasma exchange using lipoprotein-deficient plasma with those of LDL apheresis using a dextran sulphate column was undertaken in two groups of Watanabe heritable hyperlipidemic rabbits pre-labelled with 3H-cholesterol. Total and HDL cholesterol were reduced more by plasma exchange but HDL cholesterol rebounded higher after LDL apheresis; rises in HDL cholesterol correlated with preceding decreases in both HDL and total cholesterol. An increase in the specific activity of HDL cholesterol occurred on the day after each procedure, being more marked after plasma exchange, and was accompanied by a decrease in the cholesterol/phospholipid ratio of HDL. These results suggest that an influx of extravascular HDL into plasma occurred after both procedures, resulting in mobilization of tissue cholesterol.