[Effects of bone marrow endothelial cell conditioned medium and its ultrafiltration-prepared components on the growth of CFU-GM].

In this study, we obtained the serum-free conditioned medium from subcultures of murine bone-marrow-derived endothelial cell line which has been established recently by ourselves. And then, molecular weight (MW) > 10 kD, 3-10 kD, 1-3 kD, 0.5-1 kD and < 0.05 kD components were sifted out from the conditioned medium (mBMEC-CM) by means of serial ultrafiltration. Assays of granulocyte-macrophage colony-forming cell (CFU-GM) were performed to examine the effects of mBMEC-CM and its ultrafiltration-prepared components. It was not observed that mBMEC-CM and MW 3-10 kD component had any significant influence on the growth of CFU-GM. However, MW > 10 kD and 0.5-1 kD components enhanced the proliferation of CFU-GM, whereas MW 1-3 kD and < 0.5 kD ones inhibited it. All these four components exerted their effects on the growth of CFU-GM in dose-dependent way. Our observations suggest that under the conditions of in vitro, murine bone marrow endothelial cells produce several active components which have promoting or inhibitory effects on the growth of CFU-GM.