Age related changes in hemopoietic capacity of bone marrow cells

The effect of aging on the hemopoietic capacity of bone marrow (BM) cells was investigated. No difference was found in the incidence of colony forming units-spleen (CFU-S) and granulocyte-macrophage colony forming cells (GM-CFC) present in the BM of young (2-4 months) or old (24-30 months) mice. However, increased proliferation (x3) of the old BM cells was observed when cultured in the presence of L-cell conditioned medium. The cells were also cultivated over an adherent layer of a BM stroma cell line (14F1.1, endothelial-adipocytes) and the non-adherent cells removed and tested weekly. Cells originating from the old BM proliferated to a greater extent and produced more GM-CFC than those from the young. Differentiation into T-cells after colonizing fetal thymus explants was also measured and found to be reduced in both groups, though to a greater extent in the old. Thus, under the present experimental conditions, myeloid progenitors in the old BM manifest a more pronounced self renewal and differentiation capacity than the young while for the T-cell progenitors the situation is reversed.