Jesse K. Biehl, Brenda Russel
Stem cells are a unique cell in their ability to not only replicate themselves but to specialize into specific cell types. There are two types of stem cells; pluripotent and multipotent.
Pluripotent stem cells can specialize into any cell type within the body. Multipotent stem cells are more limited in their specialization abilities and can only differentiate into specific cell types. Unipotent stem cells can only specialize into one specific cell type. This unique ability makes stem cells of particular interest to regenerative medicine practitioners and researchers.
Sources of Stem Cells
Pluripotent stem cells are most commonly derived from embryos. The cells are isolated and cultured to promote cellular proliferation.
Multipotent stem cells can specialize into all of the progenitor cells for a specific germ layer or can be limited to only one or two cell types for a certain tissue. They do not have the ability to differentiate into all three of the germ layers.
Unipotent cells, the most limited of the stem cell types, are typically found “within their organ and although their differentiation capacity is restricted, these limited progenitor cells play a vital role in maintaining tissue integrity by replenishing aging or injured cells.”
Characteristics that Identify Stem Cells
Pluripotent stem cells can be identified by their ability to increase in number perpetually in vitro and have a high ratio of cytoplasm to nucleus. They require growth factors from other live cells in order to proliferate.
Multipotent stem cells can be identified using specific cell surface markers that give insight into the lineage of the cell.
Growth factors and chemical stimulants can be used to differentiate stem cells into specialized cell types.
Stem Cell Therapy
Pluripotent stems cells are not currently used in humans due to adverse reactions seen in animal models. The most common problem is unregulated growth. There have been successful studies in animal models and further research is needed.
Multipotent cells have been used in therapy since the 1960’s. Mesenchymal stem cells are now utilized in a multitude of different treatments for a wide range of conditions and diseases.