Adipose-Derived Stem Cells (ASCs) for Tissue Engineering

Abstract

A current challenge in the field of tissue engineering is soft tissue replacement. Techniques for soft tissue reconstruction include use of autologous fat transplantation, alloplastic implants and autologous tissue flaps. However, these approaches have disadvantages, including donor-site morbidity, implant migration, foreign body reaction and immune system rejection. The use of autologous stem cells expanded in vitro and combined with novel biomaterials for organ reconstruction offers a potential solution for replacement of tissue or whole organs. Stem cells, first identified in embryonic tissue and later in numerous adult tissues, possess the unique capacity to differentiate into wide range of tissue types. However, although embryonic cells are the most flexible of stem cell lines, they raise the problem of ethical issues. For tissue engineering, candidates of stem cells include embryonic stem cells (Ahn, et al.), induced pluripotent stem cells (iPS) (Crisan, et al.;2008, Parker, et al.;2007) and adult stem cells. The ability of adult stem cells to divide or self-renewal make them attractive source of stem cells for use in tissue engineering. A significant amount of current interest has focused on the possibility that adult human stem cells are the therapeutic alternative to embryonic stem cells because of their plasticity (Aoki, et al.;2010). The presence of self-renewing cells within the bone marrow of mice was reported in 1963 which was later known as hematopoietic stem cells (HSCs) (Becker, et al.;1963, Zhang, et al.;1999). Several years later, HSCs were identified in umbilical cord blood by other investigators (Aust, et al.; 2004, Dellavalle, et al.;2007). Furthermore, several other adult stem cell types such as neural stem cells (Dellavalle, et al.; 2007, Guilak, et al.;2010), were isolated and identified. Moreover, a population of plastic adherent cells were isolated from collagenase digests of adipose tissue. Adipose tissue derived stem cells were termed as: adipose derived stem/stromal cells (ASCs), adipose-derived adult stem (ADAS) cells, adipose-derived adult stromal cells, adipose-derived stromal cells (ADSCs), adipose stromal cells (ASCs), adipose mesenchymal stem cells (AdMSCs), lipoblast, pericyte, preadipocyte, and processed lipoaspirate (PLA) cells. To prevent the confusion in the literature, the International Fat Applied Technology