A NEW BIOLOGICAL GLUE FOR CARTILAGE-CARTILAGE INTERFACES - TISSUE TRANSGLUTAMINASE

In this study, we used an in vitro model to test the capacity of tissu e transglutaminase to increase the adhesive strength at a cartilage-ca rtilage interface. Full-thickness cartilage-bone cylinders were prepar ed from fresh adult bovine shoulder joints, and the superficial half o f the hyaline cartilage was then removed to provide a plane surface, T issue transglutaminase was applied to the freshly cut surface of one c ylinder, and a calcium-chloride solution (to act as an activating agen t) was applied to that of the other. The cartilage surfaces were immed iately apposed, one on top of the other, and an eighty-gram weight was applied to the upper cylinder for ten minutes at 37 degrees Celsius u nder defined humidity conditions, A measured force was then applied tr ansversely to the upper cylinder until it was displaced from the lower one (which was clamped in a holding device), and the force recorded a t this point was taken as a measure of the adhesive strength achieved at the cartilage-cartilage interface. The adhesive strength increased linearly with an increasing concentration of tissue transglutaminase ( 0.25 to 2.75 milligrams per milliliter) and was enhanced by increasing the duration of incubation, but it was not influenced by the level of humidity, The adhesive strength was improved by as much as 40 per cen t when the cartilage surfaces had been pretreated with chondroitinase AC or hyaluronidase to remove glycosaminoglycan chains of proteoglycan s, which are largely responsible for the intrinsic anti-adhesive prope rties of cartilage. CLINICAL RELEVANCE: The mechanical fixation of car tilage fragments in diarthrodial joints and the fixation and immobiliz ation of cartilage transplant materials or biodegradable matrices cont aining chondrogenic cells pose serious problems for the orthopaedic su rgeon, In the present study, the adhesive strength achieved with use o f tissue transglutaminase at the cartilage-cartilage interface was gre ater than that obtained with use of Tissucol, a commercially available fibrin sealant, Tissue transglutaminase thus has great promise for pr actical application in clinical orthopaedics. Because this material ha s a relatively simple single-polypeptide-chain structure, production o f the substance in large quantities with use of recombinant DNA techno logy is feasible, As a biological adhesive, it thus offers new possibi lities for improving the repertoire for the treatment of chondral lesi ons.