Tissue engineering, now linked with the term regenerative medicine, is a relatively new and emerging field of combined sciences. Due to its interdisciplinary approach, incorporating all specialties of medicine, engineering and basic sciences, it has resulted in extensive research and translation into medicine in a very short period. This article focuses on what tissue engineering is, what brought about the need for tissue engineering, its current status, and the promise it holds for the future.
Tissue Engineering Definition
A tissue is defined as a collection or aggregation of morphologically similar cells in an intercellular matrix acting together to perform specific targeted functions. Engineering by definition is the branch of science and technology concerned with the design, building and use of engines, machines and structures. Therefore, combining the individual definitions, tissue engineering can simply be interpreted as the design, building and use of cells and inter-cellular matrices to coordinately perform specific functions characteristic of a tissue.
Why tissue engineering came into being?
Tissue injury, damage or loss results in diminished function of the associated organ. The injury could be acute resulting in sudden loss of large amounts of tissue or chronic degeneration with ageing. Although most organs of our body have inbuilt regenerative abilities, their regenerative rate is either not capable of handling extensive damages or reduced with ageing, thereby resulting in loss of tissue. In such cases, the only solution for restoring organ function is the replacement of the lost/injured tissue with properly functioning tissue. Initially, replacement was done by obtaining excess tissue from another part of the injured individual orimmunologically matching individuals (donors) in order to prevent rejection or adverse immune responses. However, in case of repeated injuries or lack of matching donors, replacement was a problem. Tissue engineering hence emerged to address this shortage and everlasting need for healthy tissue in medicine.
Tissue engineering then and now
In the early days of tissue engineering, decellularized tissue matrices from cadavers were used to give support and growth material for seeded cells, grown in cell cultures. This then evolved to the use of engineered material, synthetic polymers, as support matrices for cell seeding. Design of engineered lungs, livers and vascular grafts are being researched using this idea.Research in tissue engineering is expanding, incorporating development of materials that deliver cells to necessary locations based on nano-scale surface topography and development of biomaterials to release bioactive factors for healing and tissue formation. The discovery of stem cells and their potential in tissue development and regeneration gives further advancing opportunities to the field of tissue engineering and regenerative medicine.Perfusion of these cells directly to the organ in need of repair is one strategy, whereas manipulating these cells chemically or genetically to migrate and differentiate into specific cell types is also being studied.
The promise that the future holds for tissue engineering and regenerative medicine is apparentfromits advance in multiple directions, involving the various specialties of science and engineering, from naturally produced stem cells to engineered biomaterials and new, creative strategies to combine the different approaches. This rapid advance of tissue engineering and regenerative medicine shows tremendous potential to health care, where in a day not too far in the future, not only acute injuries, but also chronic diseases and ageing will be combated with ease.