Regenerative medicine is a broad definition for innovative medical therapies that will enable the body to repair, replace, restore and regenerate damaged or diseased cells, tissues and organs. Regenerative medicine promises to extend healthy life spans and improve the quality of life by supporting and activating the body s natural healing. This broad field encompasses a variety of research areas including cell therapy, tissue engineering, biomaterials engineering, growth factors (induction of regeneration by biologically active molecules) and transplantation science.
Cell therapy describes the process of introducing new cells into a tissue in order to treat a disease. The FDA defines cell therapy as, The prevention, treatment, cure or mitigation of disease or injuries in humans by the administration of autologous, allogeneic or xenogeneic cells that have been manipulated or altered ex vivo. The goal of cell therapy, overlapping with that of regenerative medicine, is to repair, replace or restore damaged tissues or organs.
There are two ideas behind the use of cells as a medical treatment. The first is to provide a source of missing cells, say to heal a tissue that is injured or to renew a population of cells that are killed off by a disease such as Alzheimer’s. The second notion is to manipulate cells to produce a missing substance, such as the protein that is missing in boys affected by Duchenne muscular dystrophy. There are many potential forms of cell therapy:
- The transplantation of stem cells that are autologous or allogeneic
- The transplantation of mature, functional cells.
- The application of modified human cells that are used to produce a needed substance.
- The xenotransplantation of non-human cells that are used to produce a needed substance.
- The transplantation of transdifferentiated cells derived from the patient’s own differentiated cells.
Increasingly, mesenchymal stem cells are being proposed as agents for cell-based therapies, due to their plasticity, established isolation procedures, and capacity for ex vivo expansion.
Cell therapy may take the form of a stem cell transplant such as a hematopoietic cell transplant that is used to restore the blood and immune system of patients with leukemia, lymphoma or other blood disorders.
Activation of the body s own immune system to fight cancer is referred to as adoptive immunotherapy. This type of cell therapy is most commonly used in the fight against cancer. One type of adoptive immunotherapy treatment artificially increases the number of T killer cells (a form of white blood cell) in the patient and involves collection of patient T cells, ex vivo expansion, then reinfusion to the patient. The result is an increase in the number of T cells and a stronger patient immune response to the cancer.
Regardless of the type of cellular therapy, production of the therapeutic product may require several complex techniques to alter or manipulate the cell. Cell engineering techniques may include:
- Propagation of cells
- Expansion of cells
- Selection of cells
- Pharmacological treatment of cells
- Alteration of biological characteristics of cells