Stem cells are unspecialized cells are characterized by the ability to renew themselves through mitotic cell division and differentiating into a diverse range of specialized cell types. They are vital to the growth, maintenance, development, and repair of our brains, bones, muscles, nerves, blood, skin, and other organ thus holds tremendous promise for the development of novel therapies for many serious diseases and injuries
Classification of stem cells on the basis of potency (extent to which they can differentiate into different cell types)
- Totipoten :The ability to differentiate into all possible cell types.e.g: cells from early (1-3 days ) days embryo
- Pluripotent : The ability to differentiate into almost all cell types. e.g: some cells f blastocyst
- Multipotent : The ability to differentiate into a closely related family of cells e.g: include hematopoietic (adult) stem cells that can become red and white blood cells or platelets.
- Oligopotent : The ability to differentiate into a few cells. e.g: adult lymphoid or myeloid stem cells
- Unipotent : The ability to only produce cells of their own type, but have the property of self renewal required to be labeled a stem cell.e.g: include (adult) muscle stem cells
Classification of stem cells on the basis of their sources
- Embryonic stem cells
Early or embryonic and mature or adult. Early stem cells, often called embryonic stem cells, are found in the inner cell mass of a blastocyst after approximately five days of development.
- Adult stem cells
Mature stem cells are found in specific mature body tissues as well as the umbilical cord and placenta after birth .The primary roles of adult stem cells in a living organism are to maintain and repair the tissue in which they are found. Unlike embryonic stem cells, which are defined by their origin (the inner cell mass of the blastocyst), the origin of adult stem cells in some mature tissues is still under investigation.
Potential Therapeutic Applications of Stem Cells
One potential application is the generation of different types of neurons for the treatment of Alzheimer’s disease, spinal cord injuries, or Parkinson’s disease. The production of heart muscle cells for heart attack survivors may also be possible. The generation of insulin-secreting pancreatic islet cells for the treatment of type-1 diabetes, and even the generation of hair follicle stem cells for the treatment of certain types of baldness, have been considered.
Stem cells could also be useful for a number of tissue engineering applications such as the production of complete organs including livers, kidneys, eyes, hearts, or even parts of the brain.. Other areas that would benefit from a better understanding and control of stem cell proliferation in vitro are drug testing, cancer research, and fundamental research on embryonic development.