Y. Denizot et al., PAF AND HEMATOPOIESIS .3. PRESENCE AND METABOLISM OF PLATELET-ACTIVATING-FACTOR IN HUMAN BONE-MARROW, Biochimica et biophysica acta. Molecular cell research, 1265(1), 1995, pp. 55-60
Platelet-activating factor (PAF) is a phospholipid compound with major
immunoregulatory activities. The present study shows that human bone
marrow contains 576 +/- 39 pg PAF/ml (n = 35). Bone marrow-derived PAF
exhibits the same biophysical and biological properties that syntheti
c PAF. PAF concentrations in bone marrow are correlated with the granu
locyte (r = 0.4, P = 0.02) but not with the lymphocyte (r = 0.24, P =
0.17) and the monocyte(r = 0.12, P = 0.48) counts. In bone marrow PAF
is inactivated by a plasma PAF acetylhydrolase activity (48.0 +/- 2.3
nmol/min per mi, n = 34). Experiments with [H-3]PAF indicate that huma
n bone marrow cells actively metabolize this potent molecule by the de
acetylation-transacylation pathway. Results of this investigation indi
cate the permanent presence of significant amounts of PAF in bone marr
ow suggesting its putative involvement in the processes of bone marrow
cell proliferation and maturation.