Cryopreservation of tissue-engineered constructs in regenerative medicine

The transplantation of artificial tissues and organs is gradually becoming a part of our reality. At the same time, researchers are facing a problem common to all transplantologists, i.e. the need for a long-term storage of a biomedical product (transplant) without losing its properties. The possibility to cryopreserve cells adhered to various scaffolds' surface was first presented about 20 years ago. However, the data on the technology as a whole remains unsystematized and controversial. This review aimed to analyze the literature on tissue-engineered constructs (TEC) cryopreservation of different scientific groups to create a unified approach in assessing the technique's efficacy necessary for further regenerative medicine development. The comparison of studies on TEC cryopreservation conducted by various research groups is hampered not only by the lack of standardized protocols but also by different approaches to assessing the result. As experimental data were accumulated, the cryopreservation efficacy was reassessed from meeting the basic requirements for the structure preservation (thawed TEC retains its integrity, cells are partially alive and attached to the matrix) to focusing on the final result (thawed TEC retains its functional properties and is ready to be transplanted). Many of the currently used in vitro research methods presented in the review allow one to look for new ways of increasing the TEC cryopreservation efficacy; however, in our opinion, the next step on the way to introducing the technology into clinical practice should be research on experimental animals. Keywords: tissue engineered construction, cryopreservation, efficacy estimation