Regenerative medicine is the restoration of normal function to diseased, injured or lost tissues using therapies consisting of living human cells, tissues, or organs with or without specialized materials. The concept of using tissues to replace damaged tissues has been around for centuries. However, the field of regenerative medicine as it currently stands began to develop following the discovery of human stem cells or more specifically embryonic stem cells, in the late 1990s. Stem cells are cells capable of developing or differentiating into more specialized cells such as heart, lung, skin, pancreas and many more. Because of their capacity to generate cells from multiple lineages, researchers have begun to investigate their potential for regenerative medicine. In theory, stem cells could be harvested from a patient and used to generate many different types of healthy tissue. The tissue would then be implanted in the patient to replace the damaged or diseased tissues. Stem cells and bio-materials are the corner stone of regenerative medicine, below is a breif overview of both. Stem Cells In the human body there are two categories of stem cells: adult stem cells (ASCs) and embryonic stem cells (ESCs). ASCs are located in every tissue of the human body and give rise to new cells throughout adulthood to maintain and repair their tissue of origin.

Advantages of Regenerative Medicine  Novel Treatment for Diseases and Injuries: The long term goal of regenerative medicine is to provide permanent cures for ailments by generating functional cells, tissues and organs that can be used to replace, repair or improve lost, damaged and diseased tissue. Currently most diseases are treated with medications, surgery, and other pharmacological therapies. Regenerative medicine could revolutionize the medical industry and how we treat diseases. Having the ability to regenerate organs opens the door to increase longevity and reduce the effects of aging by replacing older malfunctioning organs with healthier functioning organs. Although this level of regenerative medicine may be several years or decades away from becoming a standard practice, successful engineering and transplantation of healthy organs are currently being performed. In a study by Atala et al (2006), urothelial and muscle cells biopsied from patients with end-stage bladder disease were expanded and seeded on to a scaffold to generate bladder constructs. These constructs were then used to reconstruct a healthy bladder. The bladders were implanted into the patients and returned normal bowel function to the patients. Personalized Medicine and Gene Therapy: Regenerative medicine offers the opportunity to use cells as vehicles for gene therapy and/or for the correction of gene mutations by replacing mutants with corrected genes.

Current Therapies Several regenerative medicine therapies are currently approved by the Food and Drug Administration (FDA) and are commercially available. These include biologics, cell-based medical devices and biopharmaceuticals. These treatments are capable of healing at a level similar or better than other standard therapies on the market. Autologous Cells: Some treatments involve the use of autologous cells harvested from the patient. The FDA recently approved use of Carticel, a treatment for defects in the focal articular cartilage that involves harvesting chondrocytes from the articular cartilage of the patient, culturing and expanding the cells ex vivo, and then implanting them into the site of injury. The treatment results in recovery that is similar to other standard treatments including microfracture and mosaicplasty (Dewan, Gibson, Elisseeff, & Trice, 2014). Some drawbacks to this form of medicine is that it typically creates a new wound and there is a delay in treatment while the cells are expanded in culture. Allogenic Cells: Other therapies use allogenic cells, or cells from sources other than the patient and that are thus immunologically incompatible. Allogenic cells with low antigenicity tend to be used for these types of treatments. The benefit is that they can be mass produced, while having a low risk of causing an adverse immune reaction.