F. Dupuis1, Nathalie Gachard1, A Allegraud1, C. Dulery1, Vincent Praloran1, Yves Denizot1
1Laboratoire d'Hématologie Expérimentale, Faculté de Médecine, 2 rue Dr Marcland, Limoges 87025, France
Tóm tắt
We have assessed the effect of platelet‐activating factor (PAF), a biologically active phospholipid present in the human marrow, on the growth of human marrow and blood CD34+ progenitors. While the metabolization rate of PAF by CD34+ cells is low (weak acetylhydrolase and acylation processes) it is readily catabolized by the acetylhydrolase activity present in the growth medium (10% fetal calf serum + 10% 5637‐conditioned medium). Treatment of marrow CD34+ cells with the non‐metabolizable PAF agonist C‐PAF (1 nM to 100 nM) immediately before semi‐solid culture significantly (p < 0.01) decreased the number of BFU‐E but not of CFU‐GM colonies. Treatment of marrow or blood CD34+ cells with C‐PAF (10‐100 nM) for 3 days in liquid medium before semi‐solid culture significantly (p < 0.01) decreased the number of BFUE and CFU‐GM colonies. Treatment of blood CD34+ cells with the two PAF receptor antagonists CV 3988 and BN 52021 (1 μ M) had no significant effect on the number of BFU‐E and CFU‐GM colonies suggesting no role of endogenous PAF in these processes. These results show that exogenous PAF downregulates human erythropoiesis and myelopoiesis, a result that might be of importance during inflammatory states.
