THE EFFECTS OF HEPARIN ON LIPOPROTEINS IN HIGH-RESOLUTION ELECTROPHORESIS OF SERUM

Sera from heparinized patients commonly display anodal slurring of bot h the alpha and beta lipoproteins when they are examined by high-resol ution electrophoresis (HRE). In this study, the authors examined the e ffect of heparin and lipoprotein lipase on the electrophoretic migrati on of alpha and beta lipoproteins in sera. The addition of 10 to 1,000 units of heparin/mL to normal sera resulted in a concentration-depend ent anodal slurring of the beta lipoproteins. At 40 units/mL, the beta lipoprotein band was not visible when the Paragon blue protein stain was used. The beta lipoprotein could be seen as a wide, faintly staini ng band with lipoprotein stain. The alpha lipoprotein band on the same gel was unaffected by the added heparin. High-resolution electrophore sis of other sera from patients who were therapeutically heparinized d emonstrated anodal slurring of both alpha and beta lipoproteins indepe ndent of heparin concentration. Immunofixation electrophoresis (IFE) s tudies confirmed that apolipoproteins A and B were slurred within thei r respective bands. Heparin activates lipoprotein lipase with release of free fatty acids (FFA) from very low density lipoproteins and chylo microns. To test this effect on migration, sera were incubated with li poprotein lipase in vitro. The anodal slurring of both the alpha and b eta lipoprotein was associated with the amount of FFA production. Indi viduals interpreting electrophoretic patterns should be aware that bot h the alpha and beta lipoproteins can migrate and slur anodally in hep arinized patients. In addition, when the beta lipoprotein band interfe res with the identification of monoclonal gammopathies, its migration can be selectively altered by the addition of 40 units/mL heparin to t he sample.