Kinetic study of serum lipoproteins, total cholesterol and triacylglycerides in various models of experimental rodent malaria

Serum lipoproteins were studied in Swiss mice infected intraperitoneally with 1 to 5 x 106 red blood cells parasitized with mild strains of Plasmodium yoelii yoelii 17 X, P. chabaudi AJ, with intermediate virulence strains of P. y. nigeriensis, P. y. yoelii 17X YM, P. berghei Anka, with a highly virulent strain of P. vinckei. The following parameters were studied: parasitaemia, liver weight, heparin flocculation test, total cholesterol and triacylglycerides, and electrophoresis of lipoproteins in a discontinuous Polyacrylamide gradient gel. In the controls, lipoprotein electrophoresis showed primarly HDL (High Density Lipoprotein), low levels of VLDL (Very Low Density Lipoprotein), LDL (Low Density Lipoprotein). During infection there was a significant increase in triacylglyceride rich lipoprotein, chylomicrons and VLDL, and a transient increase in IDL (Intermediate Density Lipoprotein) and LDL. These increases appear only beyond a threshold of parasitaemia and are related to the increase in triacylglyceride levels, while total cholesterol does not change significantly. We observed simultaneously a transient increase in liver weights. The P. chabaudi model shows these observations perfectly. The relationship between parasitism and lipoprotein metabolism could be considered as the result of various interactions: 1. A lowered clearance of chylomicrons and VLDL by endothelial lipoprotein lipase.2. An increased synthesis of VLDL related to increased lipolysis and the subsequent catabolism of VLDL into IDL and LDL.3. A metabolic regulation of plasma HDL concentration by increased levels of triglyceride rich lipoproteins (mainly VLDL) and LDL.