Tissue engineering (also called “Regenerative
Medicine”) refers to the attempt to create functional human tissue from cells in a laboratory. Its ultimate goal is to be a cure, not merely
treatment – by repairing or replacing tissues and organs that fail due to disease, genetic
errors, congenital abnormalities, or traumatic injury. Tissue engineering relies on four important
factors: the right cells to do the job, the right environment, such as a scaffold, to
support the cells, the right biomolecules, like growth factors, to make those cells healthy
and productive, and physical and mechanical forces to influence the development of the
cells. The cells can be directly harvested from the
target organ, developed from precursor—or stem—cells, or taken from lines grown in
the lab all, ideally, from the patient, as that limits problems with rejection. The supporting structures can be derived from
donor tissue from natural or synthetic polymers made to order for their strength or endurance. Biomolecules can be added directly, or coaxed
from the cells that take up residence on the scaffold. Sometimes the scaffolds dissolve
over time, but others remain to provide support to the organ. Some examples of tissues and organs that have
already been successfully tissue engineered and implanted in humans include bladders,
small arteries, skin grafts, cartilage and even a full trachea.