Even though there’s controversy over stem cell use as a treatment for diseases, most people don’t realize stem cells are routinely used for treatment today. When you hear of stem cell therapy, immediately the thought of embryonic stem cells, but there are many treatments that use adult stem cells, called somatic stem cells, successfully for a number of diseases or conditions. The identification of an adult stem cell is its ability to renew over long periods and differentiate into specialized cells even though it’s unspecialized.
Adult stem cell treatment uses stem cells that occur in every person. Most of the cells in the body only have limited ability to reproduce. They may divide as many as six times and then die. Special cells, however, known as stem cells, are the body’s repair kit and renew indefinitely.
At one time, scientists believed that these cells were only able to develop new tissues similar to the tissue found where they originated. Newer research shows that adult stem cells have the capacity for transdiffentiation. This means that they can change to another type of cell. Adults have stem cells in many organs, including the skin, bone marrow, lungs, brain and heart.
Until recently, scientists believed these cells only repaired the tissues of that organ but now scientists find they can “coax” the cells into doing the tasks of other organs. Stem cells from livers may be able to create cells that produce insulin, similar to those found in the pancreas.
Autologous Transplants
For years, doctors have successfully used adult stem cells in bone marrow transplants. Autologous transplants come from the cells of the patient receiving the transplant and allogeneic transplants are cells, which come from another person that has a close genetic match to the patient, often requiring immunosuppressant drugs to avoid rejection of the cells.
When using autologous transplants, the doctors harvest cells from the person that’s ill, freeze them and then gives the patient high doses of chemotherapy and sometimes radiation to destroy the cancer cells.
Since this treatment involves the bone marrow, it normally destroys all the functioning marrow or most of it. The frozen cells then replace those destroyed and create new cells in the patient and blood production returns to normal. Peripheral stem cell transplants, stem cells from the blood, are also used.
The benefit of using autologous cells is the lowered rejection rate, since the cells come from the patient. However, the potential for cancer to reoccur is also higher because the blood or marrow returned to the patient may also contain some cancer cells.
Adult Stem Cells
There are documented successful treatments using adult stem cells for various diseases. Autoimmune diseases such as lupus, Crohn’s, multiple sclerosis and rheumatoid arthritis as well as leukemia and aplastic anemia respond to treatment with adult stem cells. However, a number of research projects show promise in other areas too.
Because of the newly discovered ability of adult stem cells to differentiate to other cells types, the potential use of stem cell therapy for burn victims and skin replacement is great. Scientists believe that they can produce new skin tissues for grafting with the use of a single hair plucked from the patient. Hair contains keratinocyte stem cells, skin stem cells.
The scientists believe that if they remove these cells and culture them, they can create skin tissue that will defy rejection since it comes from the patient’s own body. Clinical trials using this type of graft as alternative to surgical grafts are underway for not just burn victims but also those with venous ulcers.
Neural Stem Cells
At one time, scientists believed that neural stem cells, those that function in the brain, were only embryonic. These cells are important in research into the cure for Parkinson’s disease and brought to the attention of the public by the efforts of many, including famed victim of the disease, Michael J Fox.
Today, scientists believe there are neural adult stem cells. Some other applications for the neural stem cells would be in stroke victims, spinal cord injury and other neurodegenerative diseases.
Parkinson’s disease, one of the focused uses for stem cell therapy, comes from the loss of the neurotransmitter dopamine and the body’s inability to produce more. When scientists used fetal cells in the first double blind study, they showed the cells not only survived, they produced dopamine and the patients improved with the stem cell treatment.
However, a few of the patients had the side effect of oversensitization to the dopamine or produced too much. Regardless of the side effect, the study was successful and today more than 250 patients that received treatment via the transplantation of fetal stem cell tissues.
Fetal Cells
Other companies are using techniques that don’t require fetal cells, to help find cures for conditions that involve the brain or neurological cells. NeuroNova, for example, cultures stem cells from adults and differentiates the so they produce the dopaminergic neurons missing in patients with Parkinson’s disease. Once cultured, they transplant them into the brain of the patient.
Another company, Diacrin, is culturing fetal pig cells to create xenotransplants for stroke victims. The treatments available today require the victim receive immediate therapy. If the therapy isn’t given within the first 24 hours, it’s not effective and in some cases, dangerous.
Sometimes patients don’t show obvious signs of a stroke or others have no idea when the stroke occurred. The goal for the therapy developed by Diacrin is to be effective as long as months after the patients initial stroke.
Other Stem Cell Therapies
There are many other stem cell therapies underway. One company, Neurotech, uses genetically altered brain cells to create human Interleukin-2, these are immunotherapy for gliomas, tumor cells. Studies showed that they successfully fought tumors in rats and now the company has started clinical studies. Treatment for diabetes and spinal cord injury are also important research, using both adult stem cells and fetal cells.
While the controversy over the use of embryonic stem cells continues, the primary objection is the potential for women to become pregnant, abort and produce the fetal cells for stem cell therapy. This isn’t a viable potential. One line of stem cells can produce thousands of new lines. When cells divide, scientists can create new cell lines that also divide providing thousands of cell starts for various therapies. In other words, these cells are immortal.
Embryonic stem cells are also more difficult to predict the outcome than adult stem cells used in therapy. While some researchers believe that stem cell therapy would help patients with heart conditions, imagine the problem they’d face if they transplanted embryonic stem cells in the heart and instead of producing heart cells, they produced bone cells. The adult cells tend to be more specialized.
Whether embryonic or adult, stem cell therapy shows much promise in future medical use. It may provide a way to heal almost every conceivable disease, either by creating new tissue, providing tissue that binds to damaged areas or improving the body’s immune system. Stem cell therapy may be the 21st century medical technology that rivals the creation of antibiotics.