Studies on the phenotyping system of hyperlipoproteinemias. Evaluation of a new method by enzymic staining of lipids in serum lipoproteins separated by electrophoresis on agarose.

A new electrophoresis of lipoproteins was examined as a means of defining hyperlipoproteinemia phenotypes. The serum lipoproteins of 119 patients with hyperlipoproteinemia whose serum total cholesterol (TC) concentration was more than 250 mg and/or whose triglyceride (TG) concentration exceeded 180 mg per 100 ml were determined by using a method of electrophoretic separation of lipoproteins on agarose and enzymic staining of each lipid component separately. Based on the lipoprotein-lipid profile with the acid of various parameters for distinction, i.e., Type II A, LDL-C greater than or equal to 180 mg/dl: Type IV, VLDL-TG greater than or equal to 130 mg/dl: type II B, LDL-C greater than or equal to 130 mg/dl, 119 patients were classified into Fredrickson's phenotypes of hyperlipoproteinemia. The percentages of phenotypes with those hyperlipoproteinemias were: type II A, 31.1%; II B, 33.6; IV, 29.4%; and V, 5.9% respectively. But types I and III were not observed in this survey. The characteristics of the lipoprotein profiles of each phenotype were clearly identified, and they were: type II A, high peak LDL-C and decrease of HDL-C fraction; II B, high peak of LDL-C and VLDL-TG; IV, high peak of VLDL-TG; V, prominence of chylomicrons and high VLDL-TG peak. The serial observations of the lipoprotein-lipid profiles were very useful for detecting the progressive changes in lipoproteins which occurred during the course of diseases, particularly in cases of secondary hyperlipoproteinemia. In conclusion, the new lipoprotein-lipid profile based on the agarose electrophoresis-enzymic staining method not only offers great help in classification of hyperlipoproteinemia but has contributed to therapeutic management.