Stem cells are cells found in most, if not all, multi-cellular organisms. They are characterized by the ability to renew themselves through mitotic cell division and differentiating into a diverse range of specialized cell types.
Stem cells are distinguished from other cell types by two important characteristics.
Are unspecialized cells capable of renewing themselves through cell division, sometimes after long periods of inactivity. Under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions.
A. Types of Stem cells: The two broad types of mammalian stem cells –
- Embryonic stem cells that are isolated from the inner cell mass of blastocyst. In 1998, James Thomson (University of Wisconsin-Madison) isolated cells from the inner cell mass of the blastocyst, and developed the first human embryonic stem cell line in culture.
- Adult stem cells that are found in adult tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing specialized cells, but also maintain the normal turnover of regenerative organs, such as blood, skin, or intestinal tissues.
Both adult and embryonic stem cells can contribute to the development of regenerative medicine. Embryonic stem cells (ESCs) have the advantage of multipotency and have shown themselves to be readily culturable in the laboratory. Although the degree of plasticity of adult stem cells is still unknown and there are difficulties in purifying and culturing them, the only proven stem cell-based medical therapies that are currently available rely on adult- derived stem cells from bone marrow and skin.
B. Clinical Applications in Regenerative Medicine
- Mesenchymal stem cells- present in bone marrow are capable of generating cartilage and bone.
- Insulin producing islet cells- diabetes mellitus.
- Neural stem cells- treatment of Parkinson’s disease, Huntington’s, Alzheimer’s, MS and spinal cord injury.
- Hematopoietic stem cells have been used for bone marrow transplantation.
- Endothelial stem cells in the blood and marrow could be used to induce neo vascularization.
Globally, a large number of population is suffering from many untreatable conditions which affecting their quality of life. In such cases Autologous Stem cells is the only hope of treatment or it helps in improving the quality of life.