Stem cells are the body's raw materials. They are special cells that can develop into many different cell types ranging from muscle cells to brain cells. In some cases, as when we use blood stem cells for transplantation, they can also fix, heal, or replace damaged tissues.
Stem cells are divided into two main forms: pluripotent stem cells and adult stem cells. Pluripotent stem cells can become more than one type of cell – possibly nerve cells or liver cells – making them of great interest to medical researchers. Adult stem cells can be divided further into fully developed tissues and multipotent cells, including:
Fully developed tissues, such as the nervous system, skin, and bone marrow, generate a limited range of additional cells needed for that organ or tissue to function. For example, blood stem cells are immature cells that can only become blood cells (red blood cells, white blood cells, and platelets) to replace the cells that are used up. The human body produces approximately 200 billion new blood cells every day! But the actual percentage of these stem cells in the bone marrow is typically small, so individuals preparing to donate peripheral blood stem cells receive a course of Neupogen before donating, to encourage more of the stem cells to enter the bloodstream for collection.
Induced pluripotent stem cells are adult stem cells changed in a lab to have pluripotent qualities. Scientists first reported that human stem cells could be changed into pluripotent cells in 2006. Induced pluripotent stem cells are being tested as possible treatments for diabetes, Parkinson’s disease, and other conditions. But scientists have not yet found a way to develop every kind of cell and tissue from pluripotent stem cells.
The only stem cells currently approved by the FDA to treat disease are hematopoietic stem cells (HSC), the blood-forming adult stem cells found in bone marrow that Gift of Life collects for transplant. The use of these cells to cure blood cancer and related diseases was first discovered through bone marrow transplants in the 1950s, which also led to the identification of the immune system components needed to match donors with recipients.
HSC transplants are more commonly called peripheral blood stem cells (PBSC) or marrow transplants, and are used to treat many types of blood cancer, and inherited diseases such as sickle cell and Fanconi anemia.
HSC transplants are infused through an IV into the patient’s blood where they naturally find their way into the recipient's bones where they begin creating new bone marrow, blood cells, and immune cells that are healthy and free of disease, in a process called engraftment. They also help to remove any remaining cancer cells that may have escaped earlier chemotherapy and radiation therapy the patient received.
Gift of Life donors may sometimes be invited to donate cells in support of medical research. Researchers hope that stem cell studies will increase our understanding of how diseases occur by observing how stem cells mature to become adult tissue cells. By understanding the conditions needed for stem cells to develop, researchers hope to learn more about how and why different diseases occur.
Regenerative medicine is also an area of incredible interest. The objective is to generate healthy cells to regenerate and repair tissues. Researchers hope to develop therapies for those with conditions as diverse as spinal cord injuries, diabetes, Parkinson’s disease, Alzheimer’s disease, burns, stroke, cancers, degenerative eye conditions, and more.
Researchers also use stem cells to test new drugs for safety, quality, and effectiveness before the drugs are used in human trials. For example, nerve cells could be generated from nerve stem cells to test a new drug designed to treat nerve damage, and testing could show if and how the generated cells were affected by the drug. Techniques to program stem cells into these specific tissue cells are under study.
Gift of Life is proud to be participating with research institutions and biotechnology firms in the development of new cellular and gene therapies. Donors on our registry may be invited to participate in such research, by donating either blood stem cells or mononuclear cells. Click here to learn more about donating for research at Gift of Life.