Cryopreservation Increases Availability and Usability of Ovine Adipose-tissue Derived Stem Cells for Regenerative Medicine Search
Aim: Our long-term aim is to develop a living valvular substitute using Regenerative Medicine principles, by seeding decellularized porcine heart valve scaffolds with adult stem cells and conditioning them in bioreactors before implantation. In this study, adult stem cells were isolated from sheep adipose tissue (ADSCs). However, we found it impractical to use cells immediately after propagation and thus, in order to extend their availability in time, a preservation method was needed. Methods: Adipose tissue was harvested from 6 sheep. ADSCs were isolated using enzymatic agents and cultured. The cells were tested for plasticity using chondrogenic, adipogenic and osteogenic differentiation kits and then cryopreserved in DMSO at -1400C. Viability was tested after a 3 week storage using Trypan Blue Staining. Results: Ovine ADSCs exhibited excellent plasticity and differentiation potential. An average of 18 million ADSCs were obtained from each ovine, exhibiting more than 88% viability after a 3-week cryopreservation period followed by thawing. Conclusions: DSMO cryopreservation represents a suitable method for ovine ADSCs for regenerative medicine. This method expands the usage of stem cells in vitro before they are differentiated into more specialized cells, offering large numbers of usable ADSCs with minimal cell loss at any desired time point.