Plasma cholesterol-lowering activity of monocyte colony-stimulating factor (M-CSF)

We investigated the action of monocyte colony-stimulating factor (M-CSF) on plasma cholesterol metabolism. Recombinant human monocyte colony-stimulating factor (rhM-CSF) was intravenously injected into Watanabe heritable hyperlipidemic (WHHL) rabbits that were deficient in LDL receptor. The treated rabbits showed decreases in plasma total cholesterol levels from 493 +/- 39 to 416 +/- 45 mg/dl (about 15%) during the treatment. The decrease in total plasma cholesterol level was due to decreased levels of lipoproteins containing apo B 100 such as VLDL, IDL, and LDL. The effect of M-CSF on the LDL-receptor-deficient animal in vivo and evidence from Northern blot analysis of liver suggested that M-CSF lowers plasma cholesterol level through activated uptake of lipoproteins containing apo B 100 via pathways other than the hepatic LDL receptor. We have started a clinical study to evaluate the plasma cholesterol-lowering effect of M-CSF in patients with familial hypercholesterolemia, and have observed a decreased in total plasma cholesterol level in one of three patients treated with M-CSF. M-CSF may provide new insight into plasma cholesterol metabolism and a possible new tool to treat patients with hypercholesterolemia and atherosclerosis.