Research Project
6991750
DESCRIPTION (provided by applicant): The overall objective of this proposal is to define the hypothermic storage conditions and shelf life for tissue engineered cartilage constructs (TECCs) required for commercial manufacturing and distribution. Preliminary studies employing TECCs have demonstrated that chondrocyte viability and construct biochemistry were significantly impacted by hypothermic storage in chondrocyte culture medium. The use of hypothermia as the principal means to suppress metabolism in a reversible way is the foundation of most of the effective methods for tissue and organ storage. In this proposal two solution designs (Unisol base formulations) that mimic the intracellular environment and the extracellular environment of cells will be tested at two temperatures (25 degrees and 4 degrees C) and compared with commercially available organ preservation solutions. These temperatures were selected on the basis of the two contrasting degrees of hypothermia and practical convenience in the clinical arena (ambient vs. refrigeration). Furthermore, the potential benefits of addition of chondrocyte growth factors (trophic factors) to the Unisol solutions will be assessed. Growth factors are often required for survival, maintenance and proliferation of specific cell types in vitro and some growth factors have been shown to have dramatic effects upon survival of organs under hypothermic conditions. The hypotheses for this study are that 1) the Unisol base formulations preserve the quality of stored TECCs better than commercially available organ preservation solutions, and 2) the quality of low temperature stored TECCs is improved in the presence of growth factors known to play a role in the normal physiology of chondrocytes. TECCS will be manufactured using polyglycolic acid felt and human chondrocytes. They will be employed to compare two organ preservation solutions with Unisol base formulations for up to eight weeks of hypothermic storage. Subsequently the effects of three chondrocyte growth factors upon short (days) and longer term (weeks) TECC hypothermic storage will be investigated. The quality of the TECCs will be determined by returning them to physiologic conditions and studying metabolic activity, viability, apoptosis and histology. Chondrocyte Phenotypic stability will also be assessed by analysis of relative matrix component mRNA expression following hypothermic exposure to growth factors. These studies will lead to the development and commercialization of Unisol formulations specifically designed for cold storage of tissue engineered cartilage constructs.
