046 Society for Cryobiology: Science, application and relevance of cryobiology today

Abstract

Cryobiology was established necessarily as an interdisciplinary endeavor bringing together the biological and physical sciences to solve problems seemingly impossible to many lay observers. As Peter Mazur has described, difficulties in cryopreservation stem from a “complex concatenation of conflicting variables”. No single discipline is adequately equipped on its own to resolve the problems encountered in the field. As a result, many advances have been made based on fundamental understanding and application of cryobiology. Through manipulating variables such as the type and concentration of cryoprotectant, addition and removal methods, the use of controlled rate cooling combined with induction of ice nucleation and predictions of intracellular ice formation, these advances have culminated in the widespread use of cryobiology to facilitate research, agriculture and medicine. Indeed, application of the basic science of cryobiology readily lends itself to translation. Any cell or tissue of relevance benefits from the flexibility of shelf life that cryobiology can offer. This requires cryobiologists to interact with practitioners in many technical areas. The recently emerging field of regenerative medicine demonstrates such an example. The large scale manufacturing and banking of cells has been the backbone of this evolving discipline. The current technology for laboratory scale manufacturing and cryopreserved storage of cells has been convincingly successful; yet many important technical and medical issues remain. Many cell types of interest to cellular therapy still exhibit exquisite sensitivity to the thermal stresses they experience during the cryopreservation process, and existing approaches for preserving cells are labor-intensive and operator-dependent; consequently, as allogeneic “off-the-shelf” clinical transplantation or transfusion applications continue to be developed, large-scale manufacturing methods with appropriate quality assurance and quality control has become paramount. Despite its promise, however, the development of efficient and commercially viable processes for industrial scale cell manufacturing and banking is still in its infancy. And while manufacturing or processing of patient-specific cells may not have the same scale-up requirements that large allogeneic production requires, the same quality issues with respect to traceability, documentation, and the ultimate functional viability are just as imperative. The traditional understanding of cryopreservation damage is often focused on immediate post-thaw structural preservation, whereas cryopreservation-induced stress may increase over time, often resulting in the delayed onset of cell death. Since apoptotic cell death takes at least 24 h post-thaw to manifest the “true” or “functional” viability, the development of methods to evaluate this, and subsequently mitigate it are also needed. This is of particular importance where the cells may not succumb until hours or days post-transplant, resulting in seemingly acceptable post thaw results but yielding poor clinical efficacy. Other technical considerations involve the sample container, which must be scalable and should be at least a functionally closed system to meet safety and regulatory requirements. New strategies involving injectable cryoprotectants are also highly desirable for successful application of therapeutic cells. For cell based regenerative medicine to reach its potential in mainstream clinical applications, solutions based in sound scientific understanding of the biology and physical systems will need to continue through translation to ultimately solve these technical issues. Source of funding: None declared. Conflict of interest: None declared. Erik.Woods@CookGBT.com