Autologous Approaches to Tissue Engineering

Stem cells have added a new thrust to tissue engineering. Their distinctive self-renewal and plasticity have not only optimized many tissue engineering developments, but also rendered feasible some applications which would otherwise be unattainable with somatic cells. This review focuses on general aspects of autologous tissue engineering based on so-called adult stem cells, which not only allow for a number of the therapeutic strategies envisioned for reprogrammed and embryonic stem cells, but also tend to be genetically more stable than the latter, not to mention less restrained by regulatory hurdles and ethical controversy. While the breadth of stem cell-based tissue engineering has yet to be defined in various large scale clinical applications, numerous experimental reports and the early human experience underwrite its potential. The field continues to advance robustly in an ever expanding number of laboratories around the world, yet much remains to be learned and developed, not only by scientists and clinicians, but also entrepreneurs and regulatory agencies. Nevertheless, given its scientific premises, the potential magnitude of its impact to society, and what has been achieved thus far, the perspective of stem cell-based tissue engineering reaching the mainstream of clinical practice has become a justifiable realistic expectation. Introduction The promise of tissue engineering has predictably gained renewed impetus with the addition of stem cells to its armamentarium. While the broader definition of tissue engineering includes a few non cell-based methods, the vast majority of its processes comprise different forms of cell therapies, for which stem cells, with their distinctive selfrenewal and plasticity, are particularly suitable. In addition, stem cells allow for certain engineering strategies that would be impossible with other cell types. For example, the fact that it has been difficult to expand a sizeable proportion of somatic cells in sufficiently large numbers ex vivo for the engineering of many tissues or organ substitutes can, often times, be overcome by the use of stem cells. Indeed, the virtually limitless conceptual viability of autologous approaches to tissue engineering is one of the most direct consequences of this very principle. While the breadth of stem cell-based tissue engineering has yet to be defined in different large scale clinical applications, numerous experimental reports and the initial clinical experience underwrite its potential. Still, perhaps Copyright: c © 2012 Beatrice Dionigi and Dario O. Fauza. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. *To whom correspondence should be addressed. E-mail: dario.fauza@childrens.harvard. edu Last revised August 28, 2012. Published December 10, 2012. This chapter should be cited as: Dionigi, B. and Fauza, D.O. , Autologous Approaches to Tissue Engineering (December 10, 2012), StemBook, ed. The Stem Cell Research Community, StemBook, doi/10.3824/stembook.1. 90.1, http://www.stembook. org.