Cholesterol effects megakaryocytopoiesis

Platelet and lipid profiles are elevated in individuals with atherosclerosis. We examined the effects of cholesterol on megakaryocytopoiesis, since megakaryocytes (MK) give rise to the platelets. Individuals with slightly elevated cholesterol (>190mg/dL; N=22) had lower mean platelet volumes, but higher platelet counts resulting in a higher platelet mass than individuals with lower cholesterol (<190mg/dL; N=19). Bone marrow (N=30) was cultured in autologous serum +/− growth factors. Moderate amounts of HDL- or LDL-cholesterol were added at days 0, 2, 5, and 8 of culture. Neither effected non-stimulated CFU-MK, nor did HDL-cholesterol alter colony formation in stimulated assays. All 15 donors with lower cholesterol had modest, but significant reductions (−41%) in MK colony formation when extra LDL-cholesterol (50-100μg) was added to stimulated cultures. Only 2/15 donors with higher cholesterol had similar reductions, but 9/15 had slight reductions (−10%) and 4/15 had slight increases (+13%) in colony formation. Cells/colony (CFU-MK) were not related to in vivo lipid profiles nor in vitro supplementation (N=8; 1200 colonies). BFU-MK; CFU-GEMM, CFU-GM, CFU-E, and BFU-E were not altered by adding either HDL- or LDL-cholesterol. CFU-MK from lower cholesterol people were more likely to be inhibited when forced to respond to stimulation. More smaller platelets were produced in people with slightly elevated cholesterol levels. Thus, changes in platelet profiles may start to develop in young (21-39 yrs), apparently healthy, non-smoking individuals in response to different lipid profiles.