Serum Cholesterol—Lowering Activity of Granulocyte-Macrophage Colony-Stimulating Factor

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) is a glycoprotein hormone that stimulates the growth of hematopoietic progenitor cells and enhances the functional activity of mature myeloid effector cells. Granulocyte-macrophage colony-stimulating factor was administered to eight patients with severe aplastic anemia in an attempt to restore adequate hematopoiesis. Profound decreases in serum cholesterol concentrations were observed during GM-CSF therapy that were not dependent on changes in the patients' peripheral blood cell counts. Serum cholesterol levels decreased by an average of 37% during treatment, reaching levels of less than 4.40 mmol/L in all patients. Serum cholesterol concentrations returned to baseline in all patients after discontinuation of GM-CSF therapy. Treatment with GM-CSF prominently alters cholesterol homeostasis in vivo, although the mechanism of this effect is unknown. Our results suggest that GM-CSF may be potentially useful in the treatment of hypercholesterolemia and, possibly, in the prevention and treatment of atherosclerosis.