CRYOPRESERVATION OF LIGAMENTS AND TENDONS

THE WORLDWIDE POTENTIAL MARKET FOR LIGAMENT AND TENDON IMPLANTS IS IN EXCESS OF 100,000 UNITS ANNUALLY. THE CURRENTLY AVAILABLE PROSTHETIC IMPLANTS ARE CLINICALLY UNSATISFACTORY AND AUTOLOGOUS GRAFTS MAY COMPROMISE THE SITE OF TISSUE ORIGIN. THE LONG TERM OBJECTIVE OF THIS PROJECT IS TO DEVELOP METHODS FOR PROCUREMENT, TRANSPORTATION, PRESERVATION, AND TRANSPLANTATION OF ALLOGRAFT LIGAMENTS AND TENDONS IN A LIVING, VIABLE STATE. VIABLE TISSUE TRANSPLANTATION SHOULD RESULT IN ENHANCED PATIENT REHABILITATION AND LONG-TERM GRAFT FUNCTION. THE SPECIFIC AIMS OF THIS PHASE I STUDY ARE TO INVESTIGATE IN ANEXPERIMENTAL CANINE MODEL THE EFFECTS OF ISCHEMIA UPON ANTERIOR CRUCIATE LIGAMENT (ACL) VIABILITY, AND TO DEVELOP THE PROTOCOL FOR CRYOPRESERVATION, THAWING AND TRANSPLANTATION OF ACLS. ISCHEMIA STUDIES WILL BE PERFORMED WITH INTACT ACLS FROM DOGS, USING RADIO-LABELED AMINO ACID INCORPORATION INTO PROTEINS, AND HISTOLOGY FOR ASSESSMENT OF VIABILITY. INVESTIGATIONS OF CRYOPRESERVATIONWILL INITIALLY BE PERFORMED USING CULTURED ACL-DERIVED FIBROBLASTS IN ORDER TO RAPIDLY ASSESS THE OPTIMAL RANGES FOR CRYOBIOLOGICAL VARIABLES, SUCH AS FREEZING RATE AND CRYOPROTECTANT TYPE. CELLS AND TISSUES WILL BE ANALYZED HISTOLOGICALLY, ULTRASTRUCTURALLY, AND BY BIOCHEMICAL METHODS. FINALLY, AN INITIAL PRECLINICAL TEST OF CRYOPRESERVED ACL FUNCTION WILL BE MADE BY REPLACING THE ACL IN DOGS EXPERIMENTALLY. IN PHASE II WE WILL INITIATE A MULTICENTER, LONG-TERM (2 YEARS) STUDY OF CRYOPRESERVED ACL FUNCTION AND EXTEND THE INVESTIGATION TO INCLUDE ALTERNATIVE LIGAMENTS AND TENDONS.