Heterogeneous aging of macrophage-lineage cells in the capacity for TNF production and self renewal in C57BL/6 mice.

We examined age-related changes in both tumor necrosis factor-alpha (TNF) producing ability and the replicative capacity of macrophage-lineage cells from different anatomical tissues concomitantly in mice. We have previously demonstrated that alveolar macrophages of aged mice secreted decreased amounts of TNF activity compared with that of younger counterpart. In this study, it is demonstrated that peritoneal macrophages exhibited increased TNF activity with aging, while the bone marrow-derived adherent cells secreted less TNF activity. In addition, we showed that the numbers of their progenitor cells (GM-CFUs) in the bone marrow increased with age, whereas those in the spleen did not change with aging. We conclude that age associated changes in functions and proliferative capacities of macrophage-lineage cells are tissue dependent.