Stem cells are uncategorized cells in the body that are capable of assuming the specific role of any other cell, depending on the body’s need at a particular time.
Stem cells are also capable of producing more cells of the same type (through a process called ‘self-renewal’), or of a specific type based on what the body requires (through a process called ‘differentiation’).
Stem Cells in Medical Research
Due to their unique properties, stem cells are used extensively in medical research to:
- Understand diseases and their causes better – by observing stem cells as they mature into cells in different parts of the body
- Generate healthy cells for the field of regenerative medicine – to regenerate, repair or replace diseased and damaged tissues
- Advance the knowledge available on how stem cells can be applied – for transplants and other forms of treatment
- Learn how stem cells develop into heart muscle cells – so that we could possibly induce heart muscles to repair themselves after a heart attack
- Test investigational drugs for quality, safety, effectiveness and toxic side effects – by using them on stem cells that have been programmed into tissue-specific cells, before using them on people
Stem Cells in Medical Treatment
Stem cells can be used in the treatment of certain diseases. A stem cell transplant, where an embryonic stem cell is first made to specialise into a necessary cell type, can help replace damaged or lost tissues that were affected by an injury or disease. Such a transplant can also be used to replace neurons damaged by spinal cord injury, stroke, Alzheimer’s disease, Parkinson’s disease or other neurological problems, and produce insulin for the treatment of diabetic patients.
Bone marrow transplants, due to the presence of somatic stem cells in the bone marrow, are used routinely to treat a variety of blood and bone marrow diseases, blood cancers, and immune system disorders. More recently, peripheral blood stem cells (found in the bloodstream) and umbilical cord stem cells (from new-born babies) are also being used in the treatment of these blood-based diseases.
Blood stem cells, when transplanted, also become a source of healthy blood cells for persons with blood-related diseases like thalassaemia and even cancer.
Stem Cell Transplant in Cancer Treatment
In cancer treatment, stem cell transplants are carried out to replace the cells which have either been destroyed by the cancer, or by the chemotherapy and/or radiation used to treat the disease. Most often, stem cell transplants are required for patients with cancers like leukaemia and lymphoma. Less frequently, they are also used in the treatment of other types of cancers, like multiple myeloma and neuroblastoma. These transplants also help patients with cancer recover faster from the severe effects of chemotherapy or radiation.
Typically, there are two types of transplants:
Autologous (AUTO) transplant: The healthy stem cells from the patient’s bone marrow are used for this transplant. However, these stem cells are first removed from the body and stored in a frozen state. Then, the patient undergoes chemotherapy and/or radiation to destroy the cancer cells. When the treatment ends, the stored stem cells are returned to the patient’s body through the bloodstream. Once they find their way back to the bone marrow, they begin to produce healthy blood cells and help in the recovery of the patient.
Allogeneic (ALLO) transplant: In this type of transplant, the healthy stem cells are received from a donor. Before the transplant, the patient would have undergone chemotherapy and/or radiation, both of which can kill off all existing stem cells along with the cancer cells in their body.
However, it is important to note that the donor stem cells must match the patient’s blood type and other parameters – else, the body will reject it. Usually, a stem cell donor is a family member. In relatively rare cases, the donor of the transplant is the identical twin of the patient and this is known as syngeneic transplant.
On the other hand, stem cells for allogeneic transplants can also be taken from the umbilical cord of a baby. These are usually easier to match because stem cells from umbilical cords have not yet developed characteristics that will be accepted or rejected by the patient’s body.
Although the primary method of cancer treatment remains chemotherapy and/radiation, sometimes, an allogeneic transplant can also help in enhancing the success of the treatment. This happens through a condition known as ‘Graft vs. Tumour’ where the stem cells received from the donor attack any cancerous cells that may be remaining in the patient’s body.
The type of transplant that is best suited for a patient depends on a number of factors and will be determined by the doctor. Both types of transplants come with their own set of side effects. This could range from bleeding, nausea/vomiting, fatigue and increased risk of infections for autologous transplants, and ‘Graft vs. Host’ disease (an internal conflict between cells of the donor and patient) for allogeneic transplants. The side effects may be more difficult to manage in older persons, although the doctors will prescribe medication and special diets to counter them.
Transplants, especially in patients with solid tumour cancers, are still considered only experimental and are used as part of clinical trials. What works for one patient may not work for another. Moreover, transplants are extremely expensive and still not within the purview of the common man.
Other Studies Related to Stem Cells & Cancer Cure
Some researchers have recently discovered a new type of cells, known as cancer stem cells. These are a type of cancer-causing cell, capable of dividing themselves just like ordinary stem cells. However, unlike healthy stem cells, these cells increase the number of cancer cells in the body, thus advancing the disease. Once this discovery is confirmed, treatment methods will shift their focus from shrinking tumours to finding ways to kill this new type of cells and keep them from reproducing.
According to another recent study by the University of California, it has been found that human bone marrow stem cells can be programmed to identify cancerous tissues, selectively target, and kill them through activated therapeutics. Through further study and development, this method could even emerge into an alternative to chemotherapy, eliminating the several complications and side effects that patients currently face.
Venkataeswara Hospitals has a super-speciality cancer care unit with advanced treatment facilities and experienced oncologists. To book an appointment, call 044 4511 1111.