Approaches and Impacts of Replacement, Reconstruction, and Regeneration in Medical Applications

Abstract

Artificial organs and implants still have their imperative justification in today’s patient care. Also, big efforts are made in the repair of functionality by reconstruction. Over the past decades expectations have been raised by promising the creation of tissues or even total organs with big advantages: autologous cells, full physiologic function, taking part in mechanical, physical and metabolic natural processes and the ability to grow and renew itself as a healthy organ. As a model or a dream the ability of regeneration as known from certain animals as e.g. the newt was suggested [1]. So far, the high expectations have only been fulfilled to a limited extent. Even approved products like skin substitutes have been withdrawn from market.

This situation will be re-analyzed, and some approaches which have resulted in very few approved products and procedures are outlined. Therefore, stem cell based therapies and gene therapies as well as proteomic procedures are not included in this talk. Tissue engineered products essentially need a scaffold and signals directing the cells to form a living substrate which can be placed in a defect to initiate regeneration. But at present a more realistic view considers well prepared “smart” scaffolds without cells superior if the “right” cells in the implantation site are encouraged to migrate into the scaffold and assist in the remodeling process to form the desired new tissue. Some successful examples as heart valve, knee cartilage and nerve are selectively considered and will reflect the present options with marked achievements: already major steps even if the big expectations are still far away.