Angela S. Mao, David J. Mooney
Regenerative medicine is a medical practice focused on repairing tissue damage, replacing tissue and organs, and helping diminish the effects of congenital disorders. A major complication in organ transplantation, immune rejection, may be avoided entirely with the implementation of certain regenerative techniques for repairing damaged tissue. There are numerous strategies being utilized currently by regenerative medical practitioners. Genetic materials are an important component of current regenerative medicine practices due to their ability to “mimic the native extracellular matrix of tissues and direct cell behavior, contribute to the structure and function of new tissue, and locally present growth factors.”
Therapies at the Preclinical Stage and in Clinical Testing
Recapitulating Tissue and Organ Structure
The function of an organ system is directly related to its structure. Recreating its structure is an essential component of tissue recapitulation. Donor tissue can be decellularized to remove immunogenic cells while maintaining overall composition of the extracellular matrix. The organ is then recellularized before implantation. Organ scaffolding is a synthetic version of decellularization. The organ structure is created artificially and is able to maintain some structural properties of the target tissue.
Integrating Graft Tissue by Inducing Vascularization and Innervation
Implanted tissue grafts need to be properly integrated into the body in order to be effective and successful. Engineered tissue can be integrated into the body through vascularization by utilizing the body’s own angiogenic response through the presentation of growth factors.
Vascularization can also be accomplished by vascularizing the graft itself or the target site prior to implantation.
Altering the Host Environment: Cell Infusions and Modulating the Immune System
The introduction of specific transplanted cells can therapeutically help to stabilize an injured or diseased host environment by modifying the host’s extracellular matrix, cause the secretion of growth factors, and improve tissue regeneration.
Immune engineering can reduce the likelihood of immune rejection and increase the rate of regeneration. Modification to the responses of dendritic cells and T cells increase allograft tolerance.
Existing and New Cell Sources
Finding a reliable and viable cell source is one of the many challenges a regenerative medicine practitioner must face. Currently, cells from embryonic and adult tissues are used for regenerative therapies.