1992 Volume 34 Issue 9 Pages 987-991
Hyperlipidemia may contribute to the progression of focal glomerular sclerosis (FGS) in humans and obese Zucker rats. Zucker rats undergo an increase in their plasma low density lipoprotein (LDL), very low density lipoprotein (VLDL) and oxidized lipids, resulting in the development of FGS. We examined the effects of such hyperlipidemic serum on thymidine uptake into cultured mesangial cells. LDL and VLDL both stimulated the overnight uptake of 3H-thymidine at a concentration of below 10μg/ml and inhibited this uptake at over 50μg/ml in the medium. Modified LDL and VLDL after oxidation, however, inhibited this uptake at a concentration of 1 ig/ml in the medium. Although 20% serum-containing medium stimulated the thymidine uptake by the mesangial cells, the lipoprotein fraction inhibited the uptake, while the lipoprotein-free fraction markedly stimulated it. We conclude therefore that the lipoproteins in hyperlipidemic serum suppress and the lipoprotein-free fraction stimulates mesangial growth. Both may play a role in the development of FGS in rats.
