What are stem cells, and why are they important?
Stem cells have the remarkable potential to develop into many different cell types in the body during early life and growth. In addition, in many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.
Regulatory status in Iindia:
“National Guidelines for Stem Cell Research” jointly formulated by Department of Biotechnology and the Indian Council of Medical Research was released by the Hon’ble Minister for Health & Family Welfare on 11th October; 2017. As per the National Guidelines for Stem Cell Research (2017), at present, there are no approved indications for stem cell therapy other than the hematopoietic stem cell transplantation (HSCT) for hematological disorders. Accordingly, all stem cell therapy other than the above shall be treated as investigational and conducted only in the form of a clinical trial after obtaining necessary regulatory approvals. Use of stem cells for any other purpose outside the domain of clinical trials will be considered unethical and hence is not permissible.
Stem cells are distinguished from other cell types by two important characteristics:
First, they are unspecialized cells capable of renewing themselves through cell division, sometimes after long periods of inactivity.
Second, under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions. In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, however, such as the pancreas and the heart, stem cells only divide under special conditions.
What are the similarities and differences between Embryonic and Adult stem cells?
One major difference between adult and Embryonic stem cells is their different abilities in the number and type of differentiated cell types they can become. Embryonic stem cells can become all cell types of the body because they are pluripotent. Adult stem cells are thought to be limited to differentiating into different cell types of their tissue of origin.
Embryonic stem cells can be grown relatively easily in culture. Adult stem cells are rare in mature tissues, so isolating these cells from an adult tissue is challenging, and methods to expand their numbers in cell culture have not yet been worked out. This is an important distinction, as large numbers of cells are needed for stem cell replacement therapies.