Progress has been made in the field of stem cell research over the last several decades, and the future looks even brighter. Stem cell research began with embryonic stem cells, but adult stem cells are gaining ground as the future of stem cell therapy. Adult stem cells offer several advantages therapeutically, but they do not pose the ethical concerns that embryonic stem cells do.
Functionality
Adult stem cells are undifferentiated, or non-specialized, cells found in a majority of human tissues that are capable of self-renewing and developing into specialized cell types, or differentiated, such as muscle-contraction or nerve-signaling cells. They primarily function to maintain and repair the tissue in which they reside. Therefore, the ability of these cells to differentiate into specialized cell types makes them a strong candidate for use in therapies in which new cells are needed for proper function.
Numerous Locations
The four main types of adult stem cells include hematopoietic, mesenchymal, neural and epithelial stem cells. The primary locations in the body to access adult stems cells include the bone marrow, umbilical cord blood and placental tissue, peripheral blood and blood vessels, spinal cord, skeletal muscle, fat, epithelium, and the liver and pancreas. This allows researchers and physicians a variety of avenues to collect, harvest, grow, study and therapeutically use adult stem cells.
Fewer Ethical Concerns
The controversy surrounding the use of embryonic stem cells continues, which increases the popularity of adult stem cells. Human embryonic stem cells are derived from the inner cell mass of a human blastocyst, which is a four- to five-day-old pre-implantation embryo formed after fertilization. It has the ability to form life, leading to the ethical debate over whether life is destroyed. On the other hand, adult stem cells are extracted from various human tissues or umbilical cord blood and do not require the destruction of cells that could potentially become human life.
Pluripotency
Induced pluripotent stem cells, or iPSCs, are adult stem cells that have been genetically reprogrammed to be pluripotent, which is the ability to differentiate into any cell type. This groundbreaking technology uses viruses to express the genes and factors necessary to reprogram the cells. The first iPSC from a human adult stem cell occurred in 2007, but much more research is needed for this technology to be used therapeutically in humans, according to the National Institutes of Health. However, this technology is a tool in drug development and disease modeling.
Established Procedure
One well-established therapy using stem cells in the body is a bone marrow transplant procedure. A bone marrow transplant is used to treat a variety of conditions, including leukemia and lymphoma, sickle cell anemia and to replace the loss of bone marrow in individuals undergoing chemotherapy or radiation. Bone marrow is a soft, spongy tissue on the inside of bones that contains stem cells that develop into all types of blood cells. These stem cells are extracted from a donor or from the patient's own body and transplanted into individuals lacking blood cells due to various diseases or therapies. The stem cells then differentiate into a new population of blood cells.
