Effects of plastic-adherent dermal multipotent cells on peripheral blood leukocytes and CFU-GM in rats

Multipotent cells were isolated from the dermis of newborn rats by their adherence to plastic culture dishes. Morphological observations showed that most of these elements were fibroblast-like cells described as cultured dermal multipotent cells (DMCs). These cells express CD90, CD44, CD59, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1). They display the capacity to differentiate into cells with the phenotypic properties of osteocytes, adipocytes, chondrocytes, or neurons depending upon the specific inducing media. The confluent dermal multipotent cell layer supported and promoted the in vitro growth of colony-forming unit of granulocyte/macrophage progenitors (CFU-GM) as well as hematopoietic progenitor colonies. Transplantation of dermal multipotent cells into sublethally irradiated rats led to a significant increase of peripheral blood white cells nucleated cells, and CFU-GM colonies in the bone marrow. Fluorescence in situ hybridization analysis using a Y-chromosome-specific probe showed that dermal multipotent cells could engraft into bone marrow. However, they failed to differentiate into CD45-positive hematopoietic cells and to repopulate the hematopoietic system of lethally irradiated rats. These results suggest that plastic-adherent DMCs may at least represent. an alternative source of mesenchymal stem cells to restore the marrow microenvironment and promote the survival, engraftment, and proliferation of hematopoietic cells.