Hemopoiesis on skin-derived fibroblasts in vitro.

Bone marrow fibroblasts have been shown to have a role in the support and regulation of hemopoiesis, both in vivo and in vitro. In this study we examine the ability of skin-derived fibroblasts to interact with hemopoiesis in vitro. Murine skin and bone marrow-derived fibroblasts were similar with respect to their abilities to support granulopoiesis and release colony-stimulating activity. Detailed analysis of skin fibroblast cultures 1 week after seeding with stromal cell-depleted bone marrow demonstrated that both multipotential hemopoietic stem cells and erythroid stem cells were maintained, while granulocyte/macrophage colony-forming units far exceeded inoculum values. Immunostaining demonstrated the presence of foci of T200 positive hemopoietic cells on the surface of the fibroblasts with less frequent scattered M1/70 and F4/80 positive macrophages. The majority of cells (greater than 90%) released from the stromal layer were of the granulocytic series. These findings demonstrate that the hemopoietic regulatory properties previously attributed to bone marrow-derived fibroblasts are not unique to fibroblasts derived from hemopoietic tissues.