In November 2008, history was made in Spain when scientists announced the "world's first tissue-engineered whole organ transplant using a windpipe made with the patient's own stem cells". Since then scientists all over the world have been quietly trying to emulate that achievement. Right now, in Britain, scientists are using stem cells to repair incurable brain damage in stroke patients. "Four groups of three patients will be given the treatment over the next two years, starting with a low dose of two million foetal stem cells and rising to 20 million."
The focus on stroke as the best area of embryonic stem cell research in the country is not surprising. Stroke is the largest cause of disability in Britain - affecting 150,000 people a year - and the third most common cause of death after heart disease and cancer, not to mention taking a huge slice of the National Health Service (NHS) budget. It would thus be the primary area for experiment. As far as the use of stem cells are concerned, per se, it has had slow progress until now because it is a research subject that is still in its infancy, for a variety of political and ethical reasons. However, the potential for great breakthroughs in the use of stem cells is enormous.
There are many diseases that are caused when a particular cell type in the body starts to malfunction. The basic idea is that scientists can use embryonic stem cells to repair those cells or replace them. Such cells can (theoretically) divide endlessly to replace other cells for as long as the person is still alive. Scientists have made some headway in testing their theory of potential uses, both in the lab and on animals, but they have only recently started practising on humans. However, what is so exciting about embryonic stem cells is their flexibility in becoming either muscle cells, brain cells or red blood cells. The very nature of stem cells being able to reproduce themselves easily into any kind of healthy body cells presents multifarious possibilities for curing diseases. The types of diseases involved would include degenerative genetic disorders that currently affect millions of people, such as Parkinson's disease, multiple sclerosis and muscular dystrophy.
To give examples of the possibilities, there are five known diseases for which scientists could use stem cells to make an impact on them:
1. Heart disease. This is the leading cause of death in the United States, and stem cells may provide some relief for it. Research is underway to see if injecting the cells into the heart could help regenerate damaged heart muscle caused by heart attacks. Though researchers have reported success in rodents, it has not been fully tried on any humans yet, and the limited human trials have produced mixed results, so that has still to be proven.
2. Diabetes. For the many sufferers all over the world with type 1 diabetes, in particular, whose special cells in the pancreas, called islet cells, have been destroyed by their immune system, stem cells might be an answer. In 2008, scientists reported that they had "coaxed human embryonic stem cells into becoming insulin-producing, blood sugar-regulating cells in diabetic mice." The hope is that one day soon this will also apply to people.
3. Sickle cell anemia. With this being a deadly blood disorder, it is ripe for stem cell application. Scientists would be able to replace the red blood cells in patients with their own stem cells. It seems that in current research some mice have been cured of the condition after receiving transfusions of stem cells made from their own skin cells.
4. Parkinson's disease. This degenerative disorder of the nervous system can cause tremours, stiffness, and speech problems, among other body malfunction. Research has already shown that "embryonic stem cells can give rise to the dopamine-making neurons that Parkinson's patients lack" by improving their motor function.
5. Organ failure. Naturally, the best way to ease the shortage of organs for transplants is to grow the patient's own supply. This is one area which is expected to be the most successful, and prolific, especially as they can be grown in laboratories, just like the Spanish patient's windpipe that was replaced.
Most important, stem cell grown in the lab can provide scientists with the opportunity to "engineer" their use along specialised lines when treating individual patients. However, scientists would need to overcome attempts by the patient's own immune system to reject the treatment or transplant. In this regard, scientists may be able to modify human stem cell lines in the laboratory by using gene therapy or other appropriate techniques.