The Usage of Stem Cells in Medicine
Raw material in the human body generates stem cells that may perform acts of biological resurrection. They divide, forming more cells (daughter cells), which either self-renew and create more cells or become specialized to function as brain cells, blood cells, bone, or heart muscle. Adult stem cells are tested in degenerative diseases, including heart failure. Clinical trials for blood-related diseases and cancer, using cord blood stem cells, have been very successful.
Bone marrow (hematopoietic) transplants, using adult stem cells, have been performed in the U.S. since the late 1960s. Once marrow blood cells mature, they enter the bloodstream. Umbilical cord blood stem cells are also hematopoietic. Stem cells that originate in the bloodstream are called peripheral blood stem cells (PBSCs). Cells from these three sources are used in transplants.
Categories of transplants are autologous, syngeneic, and allogeneic. The patient’s specific medical condition and donor availability help to determine which type is performed. Treatments require dedicated medical care to both the patient and donor, if applicable.
Patients receive their own stem cells, removed and frozen until the transplant occurs, in autologous transplants. Thawed after chemotherapy and/or radiation, the stem cells are then returned by infusion to the patient’s blood.
Syngeniec transplants are rare since they occur between identical twins. The risk of transplant rejection is considerably less due to identical genes and antigens.
Allogeneic transplants often come from a sibling or a volunteer whose cells closely match the patient’s. Donors receive injections for five days prior to the transplant to multiply blood-forming cells. The patient undergoes chemotherapy and/or radiation to kill as many cancer cells as possible before the transplant. Donor stem cells, collected by an apheresis machine, create immune cells which may destroy any remaining cancer cells. This is referred to as “graft-versus-cancer” effect. After the 1-5 hour infusion through an IV line, the donor cells travel from the patient’s bloodstream to the bone marrow. New white and red blood cells and platelets are produced in a process called “engraftment.” The engraftment usually takes between 2-4 weeks and is confirmed by frequent blood counts.
Risks for the bone marrow donor may include anesthesia complications, fatigue, or soreness at the removal site. PBSC donors require no anesthetic but may develop hand tingling or cramping, chills, or lightheadedness. Rejection is also a possibility with a donor transplant. Graft-versus-host disease occurs when donor cells attack the patient’s body.
Stem Cell Therapy greatly benefits many diseases, including:
- Kidney function
- Neuroblastoma (brain cancer in small children and infants)
- Leukemia and lymphoma
- Multiple myeloma
- Regenerative medical therapy
- Cardiovascular disease