Stem cells have the potential to develop into most tissues found in the body. They are undifferentiated cells with the potential to renew themselves, or under certain conditions, to differentiate into various tissues or organs. Stem cells have the ability to proliferate or renew themselves for many generations without a problem. They are thought to have the ability to regenerate injured or damaged tissue in the human body, possibly curing a number of chronic diseases.
Infection
Stem cells derived from donors, animals or grown under experimental conditions have the potential of causing infection in the recipient. In the September 2007 issue of "Haematologica," Marie Robin and her colleagues showed that infection with adenovirus is a significant source of post-transplant problems. Further, cells grown in the laboratory are often cultured in media with factors derived from animals, which can result in potential infection from the animals. Stem cells can be reprogrammed to develop into different cell types. This often requires insertion of viruses to express certain genes, which could potentially cause problems.
Tumors
Stem cells derived from embryonic or fetal tissue can result in the growth of tumors. Research does not indicate tumor development after treatment with adult stem cells, however. Bone marrow transplants have been used for many decades to treat a number of conditions without the formation of cancer. A number of cancers have been recently shown to have developed from stem cells found naturally in the body. These stem cells derive mutations and generate a large number of differentiated cancer cells. Further, a review from the University of Pittsburgh, published in "Tissue Engineering: Part B Reviews" in 2010, suggests that stem cell treatment following cancer treatment may promote the growth of an active, aggressive tumor, particularly if the cancer is not in remission.
Rejection
Stem cells from a donor have the potential to be matched to the recipient, reducing the risk of rejection. However, it may still be required for the recipient to be on immunosuppressive drugs for the rest of his life. It is possible to remove the patient's own cells and culture them in the laboratory to increase their number, though culturing in the laboratory can increase the risk of infection.
References
- "Haematologica"; Disseminated Adenovirus Infections After Allogenic Hematopoietic Stem Cell Transplantation: Incidence, Risk Factors and Outcome; Marie Robin et al.; September 2007
- "Current Opinion in Hematology"; Reprogramming Adult Hematopoietic Stem Cells; S. Kaneko et al.; July 2010
- "PLoS Medicine"; Donor-Derived Brain Tumor Following Neural Stem Cell Transplantation in an Ataxia Telangiectasia Patient; Ninette Amariglio et al.; February 2009
- "Cancer Cell International"; Role of Stem Cells in Cancer Therapy and Cancer Stem Cells: A Review; J. Sagar et al.; June 2007
