Modern genetic science is giving doctors and researchers an unprecedented ability to understand the human body, to repair it, and possibly even to improve it. Some of this is thanks to stem cells. The cells in the body are not all identical. As an embryo develops into a fetus, the embryonic stem cells start to specialize; by infancy, cells in each organ are specific to that organ. After a child is born, somatic stem cells are generated in bone marrow for use in repairing damaged tissue. Embryonic stem cells are pluripotent, meaning they have the potential to fit in as part of any organ, while adult stem cells are multipotent, meaning they can differentiate into many but not all cell types, depending on where they were derived from. Researchers are slowly learning to use these cells to improve treatments for people with serious illnesses.
In fact, the potential benefits of this research are tremendous. These techniques could be a boon in pharmaceutical testing, for example, enabling researchers to observe the effects of medication on actual organs—not analogues or computer simulations—without risking test subjects’ heath. This will help drug makers in creating medications that are effective while still being safe. In addition, pluripotency means these cells can replace damaged, defective, or missing cells anywhere in the body. Many genetic conditions result in a part of an organ, even the brain not functioning properly, or even not being there at all. In neurodegenerative disease, neurons die off. With stem cells both of these problems can largely be solved.
Already, researchers are looking at ways to coax stem cells into forming transplantable organs, with properly differentiated cells, that are an exact match for patients. Normally transplant patients need to be careful to avoid rejections, in which the immune system recognizes the transplanted organ as a foreign body and tries to expel it. Stem cells can make transplant organs that are not foreign and will not be rejected.
In a recent advance, scientists were able to use cells from an adult to create pluripotent stem cells, rather than merely multipotent. This means that stem cells from embryos—which are controversial and hard to come by—may not be needed for pluripotency. Though the cells created in the study are not medically useful, the technique may prove to be.