Stem cells are the progenitors of all the body’s cells. They are capable of differentiating to generate our blood components, muscle, cartilage, bone, and fat cells, and neurons; they also replace cells that have been sidelined due to age, disease or trauma.
Scientists have learned how to extract stem cells from blood. The most suitable blood for that purpose turned out to be umbilical cord blood that is collected after the baby is born and the cord is cut: it’s used to treat more than eighty-five maladies, including leukemia and immune disorders. The biomaterial preserved after babies are born will be usable not only for the children themselves, but for their biological siblings. However, a decision to keep a child’s stem cells must be made before the birth, since cord blood can be collected only immediately after; there won’t be another chance. Separated stem cells are frozen and sent for storage at a cord blood bank, where they are cryopreserved in liquid nitrogen. Not for free, naturally. However, once it’s paid, you have lifetime bioinsurance—a policy you can use if you become seriously ill.
At the immunity level
The possibilities of cell therapy don’t end there. Stem cells are used to treat lymphoma, to restore blood formation after knock-out doses of chemotherapy, and to treat patients with serious damage to spinal medulla. And there’s a vaccine for prostate cancer that is made by extracting immune cells from the patient’s blood, activating them against prostate cancer cells, and then returning them to the patient intravenously several times, inducing an immune reaction to the tumor. This vaccine has been registered successfully at the FDA and is already being used.
To deliver it to the heart
Cell therapy is used in treating myocardial infarction—heart attack—and its consequences. Stem cells are capable of becoming new myocardial cells and participating in the formation of new blood vessels. To deliver cells to their destination, they may be introduced into the arteries feeding the heart, injected directly into the myocardium, or infused by catheter through the femoral artery. One of the newest developments by cardiac surgeons involves both laser surgery and stem cells, performed on people with severe ischaemic heart disease when neither stenting nor ?oronary artery bypass surgery helps.
Blindness is cancelled
Ophthalmologists, too, have high hopes for stem cells. They are using the cells to try to stop loss of vision for patients with macular degeneration, a malady that strikes the retina and damages central vision. Moreover, stem cells are used during corneal transplants; they slow the rejection process and help preserve the transplant. They are used in cell therapy if hormones and cytostatics don’t work on certain patients. Efforts to create an artificial retina are also in progress. Ophthalmologists have already learned to grow pigmental epithelium, cultivate cells, and plant and replant experimentally. True, it’s still too early to talk about an artificial retina ready for clinical use, but five or six of the world’s leading laboratories are working on that problem.
The prospects for cell medicine are unlimited: stem cells can be useful in treating wounds, burns, fractures, autoimmune disorders, the consequences of strokes, hepatitis, and other severe maladies. It’s important to note that cell technologies have fundamentally squeezed out the idea of cloning, because scientists have realized that new organs can be obtained by other means. They hope that in the future it will be possible to grow organs for transplantation under laboratory conditions, in which case the need for donor tissues and organs would fall by the wayside: those that have been grown from the patient’s own cells would take root without risk of rejection. Experiments in that direction are in full swing. Scientists from the University of Texas and Columbia University Medical Center in New York City are making progress in growing lungs; bioengineers at the University of Michigan in Ann Arbor have been able to grow heart muscle tissue; and the Swiss scientists Simon Hoerstrup and Dorthe Schmidt at the University of Zurich have grown heart valves. A group led by James Wells at the Cincinnati Children’s Hospital Medical Center in Cincinnati, Ohio has grown three-dimensional structures of the human stomach “in a test tube,” and molecular biologists at the Genentech Corporation in California have succeeded in growing a prostate. A group of Japanese scientists at the University of Tokyo and Kyoto University led by Thomas Cervantes grew an ear, while a group Swiss scientists at the University of Zurich has grown human skin threaded with blood and lymphatic vessels.