Advances in Viable Ice-free Cryopreservation of Heart Valves

Abstract

Investigation of heart valve cryopreservation has been employed as a model for development of new methods of tissue preservation based upon vitrification and nanowarming using Fe nanoparticles. Cryoprotectant cytotoxicity can be reduced by performing the last cryoprotectant/nanoparticle exposure step below zero degrees centigrade at -10C. Tissue viability outcomes can be improved by supplementation of cryoprotectant formulations with disaccharides and nanowarming can rewarm such complex tissues with retention of cell viability from storage temperatures below -135oC to -25oC in 80-100 seconds. It is anticipated that ice-free tissue cryopreservation methods for tissues up to 50 mLs can be developed that do not require the use of nanowarming, since we are already close to achieving this with heart valves at 30 mL volumes. However, at larger volumes nanowarming will likely continue to be the best warming method for retention of tissue cell viability. Further studies to optimize cryopreservation of cardiac muscle, the somewhat fibrous muscle band at the base of heart valves, and pulmonary and aortic arteries need to be performed since it is clear that different heart valve components vary in their preservation requirements. It is anticipated that other complex tissues may also have components with different cryopreservation requirements including nanowarming.