Paul Lucas
New York Medical College, USA
Title: Multipotent Adult Stem Cells (MASCs): Differentiation and regeneration
Biography
Biography: Paul Lucas
Abstract
Tissue regeneration in adult humans requires large numbers of cells. We are working with a unique population of adult stem cells: multipotent adult stem cells (MASCs). MASCs have properties which make them uniquely useful for tissue regeneration: 1) an apparently unlimited proliferation potential in vitro, 2) the ability to differentiate into phenotypes of all 3 dermal lineages, 3) ability to respond to local signals to differentiate to the tissues at the site and 4) do not elicit an immune rejection response.
MASCs have been isolated from embryonic chicks, adult rats, mice, rabbits, and humans. They have been isolated from skeletal muscle, bone marrow, fat, and skin. MASCs from all species and all tissues are isolated and cultured by the same protocol, and they all exhibit the same proliferative and differentiation behavior in vitro and response to local factors in vivo. Differentiated phenotypes observed in vitro include skeletal myotubes, chondrocytes, osteoblasts, adipocytes, smooth muscle cells, endothelial cells, cardiomyocytes, fibroblasts, astrocytes, neurons, oligodendrocytes, keratinocytes, hepatocytes, pancreatic islet cells, and epithelial cells. Rat MASCs have been taken to 300 cell doublings, mice to 600 cell doublings, and human to 100 cell doublings.
In vivo regeneration models where MASCs have been tested include meniscal defect in rabbits, cartilage defects in rabbits, femoral and calvarial bone defects in rats, dermal defects in rats, an open tibial defect in rats, and injection sub-q of human MASCs into young adult rats. In the open tibia defect (Fig 1), MASCs were observed to differentiate into 7 phenotypes: keratinocytes, hair follicle cells, gland cells, endothelial cells, smooth muscle cells, fibroblasts, and periosteum. When injected into young adult rats, human MASCs were observed to differentiate into endothelial, smooth muscle, and hair follicle keratinocytes.
MASCs have the potential to regenerate tissues and become a useful tool in regenerative medicine.