Abstract
M.Tech.
Stem cells possess self-renewal capacity, long-term viability, and multilineage potential. Stem cells play important roles in normal physiological and disease processes, they also have great therapeutic potential. However, there have been controversies surrounding stem cells in political, religious and ethical arenas. Although the use of certain stem cells (i.e. embryonic stem cells) and the means by which they are obtained contravene certain basic ethical laws, researchers have developed methods with which to ethically obtain and create stem cell lines. Stem cells can be classified as either: totipotent, pluripotent, multipotent, oligopotent and unipotent (Moore, 2007). Totipotent cells have the ability to differentiate into all cell types of an embryo, including the extra-embryonic and post embryonic tissues and organs. Pluripotent cells have the potential to differentiate into almost all tissues found in an embryo (including germ cells), but are not capable of giving rise to supporting cells and tissues. Multipotent stem cells have progeny of several differentiated cell types - but all within a particular tissue, organ, or physiological system. A good example of multipotent cells, are the haematopoietic stem cells that produce blood cell-restricted progenitors, as well as all cell types and elements, such as platelets, that are normal components of blood. Oligopotent stem cells produce two or more lineages within a specific tissue, such as neural stem cells that are able to produce subsets of neurons in the brain. Unipotent cells self-renew, as well as give rise to a single mature cell type, a prime example being the spermatogonial stem cells, that give rise to spermatozoa (Moore, 2007).
Adult human subcutaneous adipose tissue contains cells with multilineage developmental plasticity like marrow-derived mesenchymal stem cells (Strem et al., 2005, Tong et al., 2000). Adipose derived stem cells can be obtained in abundance and can differentiate into osteogenic, adipogenic,
myogenic and chondrogenic lineages when treated with appropriate growth factors.