Plasma lipoprotein separation by discontinuous density gradient ultracentrifugation in hyperlipoproteinemic patients

Quantitative plasma lipoprotein separation is usually performed by sequential ultracentrifugation which because of the necessity of repeated ultracentrifugation is extremely time consuming and results in changes in lipoprotein composition. We describe a simple, reliable, and rapid method for quantitative plasma lipoprotein separation which is based on ultracentrifugation of the plasma in a discontinuous density gradient media consisting of a saline solution of different densities placed over a plasma solution of 1.250 g/ml (with potassium bromide). After 48 hr of ultra-centrifugation in a swinging bucket rotor excellent lipoprotein separation was demonstrated. The lipoproteins were pure and there was significantly less loss of high density lipoprotein protein to the lipoprotein deficient plasma (d greater than 1.210 g/ml) when compared to the losses incurred during the sequential flotation method. The results of separating the plasma lipoproteins from subjects with dyslipoproteinemias by this method were demonstrated. We conclude that discontinuous density gradient ultra-centrifugation is the method of choice for quantitative plasma lipoprotein separation for both clinical and research use.