Tears dry up and hope gives way to forced acceptance of fate! Is there not a ray of hope for the relatives and patients of painful, physically debilitating illnesses like cancer, blood disorders, cerebral palsy, diabetes and several other diseases? The trauma of the patients and their close relatives have kept prodding the heart and mind of physicians, leading to many inventions and discoveries that can ease the pain and restore healthy normal life to the sufferers. One such discovery in the medical field is that of the potential of stem cells in curing diseases, where some important organ stopsfunctioning. Stem cell research has awakened hope in many terminally ill patients. The world is eagerly awaiting the results of this still ongoing research as scattered news of successful treatment pour in from around the world. In some part of the world young parents of a beautiful seven year old boy frantically search the net for possible stem cell treatments of cerebral palsy for their only child. Somewhere else, a young man with dreams of the future hopes to get on with life and love fighting cancer, through stem cell treatment. So many desperate, praying, tear-filled eyes are focused on this research on regenerative medicine!
What is stem cell?
Life starts with a single cell. One cell multiplies into many, forming the different parts of the body. Once the body is fully formed, the body organs and the cells within become fixed and have specialized roles/functions. For example, once a cell becomes a liver cell it can divide/multiply into liver cells only. Stem cells are different! They are also present in our body like other cells, but they are different from the specialized cells. Stem cells are ‘undifferentiated’ or ‘unspecialized’ cells which are capable of dividing themselves and still remaining unspecialized.
The characteristics of stem cells that differentiate them from other cells are-
- Stem cells are capable of dividing and renewing themselves for long periods, sometimes even after long periods of inactivity. Other cells like muscle cells, blood cells, nerve cells etc. do not normally replicate themselves. Stem cells may replicate many times.
- Stem cells are unspecialized. They do not have any tissue-specific structures that allow it to perform specialized functions.
- Stem cells can give rise to specialized cell types, by passing through several stages, known as the process of differentiation. Each new stem cell, when it divides, has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a red blood cell or a brain cell.
Stem cells are found in fetuses, umbilical cord blood and bone marrow in adults.
Umbilical cord blood
Umbilical cord blood is a rich source of stem cells. Like normal blood, the umbilical cord blood too contains red blood cells (RBC), white blood cells (WBC) and platelets. In addition to these the cord blood also contains stem cells. The umbilical cord is a medical waste after childbirth. The cord blood containing the precious stemcells can thus be easily harvested for future use from the umbilical cord. The umbilical cord blood is the blood that remains in the placenta and in the attached umbilical cord after child birth. Cord blood is obtained from the umbilical cord at the time of childbirth, after the cord has been detached from the newborn. The placenta is a much better source of stem cells because it contains ten times more stem cells than the cord blood.
Cord blood must be stored in liquid nitrogen at minus 196 degrees Celsius in cryogenic tanks. It has no shelf life and can be preserved life long. New parents can either donate cord blood or preserve it for their own child if and when the need arises. Matching becomes easier if the patient’s own or sibling’s stem cells are infused. Although some concerns have been raised that using own cord blood may pass on certain genetic problems too.
Cord blood v/s Bone Marrow
Cord blood stem cells have more benefits than adult stem cells or bone marrow cells. Adult stem cells typically generate the cell type of the tissue in which they reside. For example- a blood forming adult stem cell in the bone marrow normally gives rise to blood cells only. It cannot give rise to the cells of a very different tissue such as nerve cells in the brain. Whereas cord blood stem cells can be induced to become any tissue or organ specific cells.
Success rates of cord blood and bone marrow transplants are similar. In both cases success rate is about 70 %. But bone marrow transplants involve more risk of complications as the extracted stem cells from bone marrow are more sensitive. The stem cells in cord blood are more ‘naïve’ and tolerant than those in the bone marrow. Therefore in case of cord blood matching does not have to be as strict as that of bone marrow cells. In case of cord blood cells there is also a lower risk of graft-versus-host disease, a complication that causes the body to attack the transplanted stem cells.
Stem cell treatment
Stem cells are used as effective treatment in combating many forms of human diseases; particularly those affect the body at the cellular level. Stem cells help in regeneration of damaged tissues. When injected into the body intravenously (at the site of affected organ), the stem cells migrate to the affected area and help regenerate the damaged tissue by multiplying. The stem cells are injected in combination with standard care for the particular disease being treated.
Stem cell treatment research in various diseases
Cancer- Stem cells has been used to successfully strengthen immune system after cancer treatments. Leukemia patients require chemotherapy and radiation to kill the cancer cells and to suppress the immune system, so that the new stem cells are not rejected. Then the stem cells are injected into the patient’s body that travels to the bone marrow cavities, where they create new, healthy marrow.
Heart attack- In heart attack cases stem cell therapy is expected to reduce inflammation and promote tissue regeneration, to reverse cardiac deterioration following a severe heart attack. If stem cells can effectively prevent or repair heart muscle damage, there is potential to reduce long term complications like repeat heart attacks and heart failure.
Stroke- In Texas doctors experimented on a stroke patient who came in too late to receive clot-busting drugs. Doctors decided to use stem cells from the patient’s own bone marrow. The adult stem cells were taken from the patient’s leg and injected. The stem cells migrate to the area of injury in the brain to do the repairs.
Liver transplants- Liver transplant is the only option in liver diseases. Because matching donors for liver transplant is a huge problem, research is on for stem cells for liver regenerative treatments. A preclinical study found that infusions of human cord blood derived cells efficiently engrafted into damaged liver and gave rise to hepatocyte like cells, suggesting that cord blood stem cells may home to injured liver and stimulate tissue repair.
Cerebral Palsy- Stem cells have the potential to regenerate brain tissues and other injured cells. In Germany two ten year old boys were treated for cerebral palsy, using stem cells. Stem cells were taken from the patient’s bone marrow to turn them into brain cells, which then go up to the brain and repair sites that were damaged.
Stem cell treatment is still in the research stage. In India, stem cells have been successfully used in heart cases, but there still isn’t any case of cerebral palsy treatment. But hope never dies! Human intellect and endeavor never gives up easily. There are bright chances of the seeds of hope to grow into fruitful tree in the near future.
(References – Cryobanks International website and website of The National Institute of Health Resources for Stem Cell Research).