Regenerative medicine

Regenerative medicine is a branch of medicine and bioengineering that tries to restore the structure and function of damaged or diseased tissues and organs, rather than only managing symptoms. Its main tools are cell therapy, in which living cells are given to a patient; tissue engineering, in which cells are grown on scaffolds that imitate the extracellular matrix to build new tissue; biomaterials and growth factors that coax the body's own repair; and, more and more, gene therapy and gene-edited cells.

Adult humans regenerate poorly compared with salamanders or zebrafish, which can regrow limbs or heart muscle, so the field tries to boost or replace this capacity. Stem cells are central to it: multipotent cells such as hematopoietic and mesenchymal stem cells, and pluripotent embryonic and induced pluripotent stem cells, which can be turned into almost any cell type. The bone marrow transplant is a long-standing example. Approved products also include engineered skin substitutes for burns and chronic wounds and implants of a patient's own cultured cartilage cells to repair the knee.

Researchers are testing lab-grown cells for Parkinson's disease, type 1 diabetes and heart damage, along with organoids, 3D-printed tissues and ways of growing whole organs for transplant. Many approaches remain experimental, and regulators such as the US FDA must approve such products before sale.