“Stem cell research is the key to developing cures for degenerative conditions like Parkinson’s and motor neuron disease from which I and many others suffer. The fact that the cells may come from embryos is not an objection, because the embryos are going to die anyway.”
– Stephen Hawking
There are some ways during which human stem cells are often of use in basic research and clinical research. Stem cells independent of their source represent a multi-usable medical or biological system, which may be used for answering different scientific, and medical or therapeutic questions. For a few of them, embryonic stem cells will be the simplest cellular source, whereas for other applications, one of the adult sources -from pluripotent to unipotent- will offer the needed properties.
- Studies of human embryonic stem cells may yield information about the complex in vivo events that occur during the developmental stages.
- A primary goal is to study how undifferentiated stem cells differentiate and proliferate. The regulation of the expression of various genes is central to this process. The medical conditions, like cancer and congenital disorders, are due to abnormal cell division and differentiation. A better understanding of the genetic and molecular controls of those processes may yield information about how such diseases arise and suggest new strategies for their treatment.
- Stem cells could be of use in testing new drugs. An example, researchers use neoplastic cell lines to screen potential antitumor drugs. But, the availability of pluripotent stem cells would allow drug testing in a wide range of cell types.
- Perhaps an important potential application of human stem cells is the in vitro regeneration of required cells and tissues, comparable to in vivo tissue/organ in structure and function, for cell-based therapies.
- Today, donated organs and tissues are used to replace damaged tissues, but the necessity for transplantable tissues and organs far outweighs the availability.
- Stem cells, induced to differentiate into specific cell types, offer the likelihood of a renewable source of replacement cells and tissues to treat diseases including Parkinson’s and Alzheimer’s diseases, spinal cord injury, stroke, burns, cardiovascular disease, diabetes, osteoarthritis, and autoimmune disorders. As an example, it’s going to become possible to get healthy muscle cells within the laboratory then transplant those cells into patients with chronic heart disease.
- Preliminary research in mice and other animals have indicated that bone marrow stem cells, transplanted into a damaged heart, can generate cardiac muscle cells and successfully repopulate the cardiac tissue.
- Other recent studies in cell culture systems indicate that it’s possible to direct the differentiation of embryonic stem cells or adult bone marrow cells into cardiac muscle cells.
- In type I diabetes, pancreatic islet cells that produce insulin are destroyed by the patient’s immune system. New studies indicate that it’s going to be possible to direct the differentiation of human embryonic stem cells in vitro to create insulin-producing cells that eventually can be employed in transplantation therapy of diabetic patients.
- Last but not least, the use of stem cells will also provide an ethical advantage over using animals for experimentation.
However, there are many technical hurdles in the promise of stem cells which can only be eliminated by intensive research work.
Unknowns and Challenges in Stem Cell Research
- It is uncertain that human embryonic stem cells in vitro can differentiate into all cell types of the adult body.
- Abnormalities may arise in chromosome number and structure during in vitro proliferation of stem cells.
- The possibility of immune rejection of stem cell transplants is very high.
- The use of mouse feeder cells for in vitro culture of stem cells could result in problems due to xenotransplantation.
- The is a high possibility of contamination of the culture by viruses, bacteria, fungi, and mycoplasma.
- Also, there is a lack of good scaffolding material to be used in tissue regeneration.
- Kruse, C., Danner, S., & Rapoport, D. (2008, February 26). Current Stem Cell Technology: Limitations and Realistic Expectations. Retrieved August 16, 2020, from https://onlinelibrary.wiley.com/doi/pdf/10.1002/elsc.200820226 Tanne,
- J. (2005, June 25). US stem cell research progresses despite limitations. Retrieved August 16, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC558486/