The field of organ transplantation has made great strides from 1954, when the first organ transplant occurred in the United States. Without immunosuppressive drugs to prevent the rejection by the recipient of the organ, the only possible transplant was a kidney from a living donor to an identical twin recipient. Today, the list of patients in need of an organ for transplantation far exceeds the available supply.
Although the annual number of people in the United States who receive a kidney transplant is about 17,000, the number of people awaiting a transplant in 2011 was in excess of 87,000. The total number of people waiting for an organ transplant of any type in the United States exceeds 110,000. In fact, the issue of a shortage of available organs for transplantation is a worldwide problem.
The ethical issues surrounding organ donation have sparked debate. Surgeons struggle to reconcile the lives of their patients with issues such as gifting an organ for money or the issue of donors being compelled to give their consent to an organ donation.
Physicians and researchers such as Dr. Alan Russell, working in the field of tissue engineering and regenerative medicine, and Dr. Susan Lim, who is exploring the transplantation of cells instead of organs, are looking for substitutes for how we currently respond to disease. Cell transplantation could circumvent the issues posed by whole organ transplantation.
Susan Lim, who pioneered liver transplantation in Asia, has turned her focus to cells. Implanting stem cells that can grow and cause the body to heal itself could replace whole organ transplants. Her early research using human fat stem cells harvested from adults focused on creating insulin-producing cells for the treatment of diabetes.
Embryonic stem cells were considered the most appropriate cells because of their ability to release growth factors to repair organs, muscles or other parts of the human body damaged by disease. Embryonic stem cell research comes with its own controversies. Although they offer the greatest ability to regenerate when transplanted, harvesting stem cells from human embryos has been at the center of controversy and debate in the United States and elsewhere.
Researchers are now exploring fat stem cells harvested from adults. The limitation with adult stem cells is that mature cells are more restrictive in their behaviors than embryonic stem cells. Restrictive behavior meant that the mature cells might not offer the growth factors needed to repair damaged organs.
Fortunately, other researchers working with mature stem cells have succeeded in reprogramming adult stem cells to produce the same results associated with embryonic stem cells. Reprogrammed adult cells eliminate the controversy that has delayed scientific studies dependent upon the collection of embryonic stem cells from human embryos.
The search to find the key to unlocking the secret to regenerating tissue and organs continues with stem cell research. Stem cells appear to offer the greatest hope for the development of less invasive ways to treat disease.