Stem cells are unspecialised cells of the body, which are capable of renewing themselves through cell division. Under certain conditions they can be induced to differentiate into organ specific cells capable of a specific function. In some organs such as the gut, stems cells regularly divide in order to repair and replace damaged tissue. In other organs such as the pancreas, stem cells will only divide under special conditions. Clinical scientists are currently researching the possibility that stem cells can be produced to secrete insulin and therefore provide a potential cure for diabetes.
The source of stem cells for research has been an area of great debate and discussion of ethical issues. Scientists generate human embryonic stem cells from embryos created for reproductive purposes during in vitro fertilisation. These cells can divide in cell culture to generate millions of potential cells for transplantation. For diabetes research the key is to engineer them to produce insulin and then for these cells to avoid being destroyed by the immune cells of the recipient.
Adult stem cells are also a potential source of transplant material and these can be found in many organs including the pancreas. They are unspecialised cells thought to be capable of differentiating into cells involved in damage repair in that particular tissue. Their capacity to divide in the laboratory is quite limited and this makes the generation of large quantities of stem cells difficult.
Even though cell based therapies cannot at present offer a cure for patients with diabetes, the science in this area is moving fast. It is now possible to reprogram adult stem cells to become embryonic stem cells with their high capacity to divide in cell culture. This could, for example, provide a source of insulin producing cells that are specific to the person needing treatment and thereby avoid the problem of immune rejection when the cells are transplanted back into that person.
For any patient exploring the idea that stem cell transplants will eventually provide a cure for diabetes it must be understood that there are currently many potential barriers. The generation of sufficient stem cells and the differentiation of the cells into insulin secreting cells is still a scientific discipline, which is relatively in its infancy. The science behind the survival of the stem cells after transplant and the long-term integration into the recipient's body needs much more study in order to overcome what are significant technical hurdles. We really don't know at this stage if stem cell transplants will function appropriately for the duration of the patient's life.
Perhaps the one salient point always to remember in medicine is that while we strive to help our patients we should avoid doing harm in any way. The genetic manipulation of cells throws into the mix the potential to induce neoplastic cancer cells. When the opportunity arise to offer a cure for diabetes using this technology life long monitoring of patients will not only need to be intensive and vigilant to study the benefits but also the potential complications. It is understandable if patients are constantly bombarded by Internet newsflashes of possible cures to be tempted to explore further. It is unnatural not to want the very latest in treatment. This subject, and particularly because of the risks, should be considered an area of medicine that demands the very highest standards of scientific rigor. The clinical results and risk-benefit assessments must be supported by peer reviewed evidence based research.