FIBRIN GLUE: BIOLOGICAL PROPERTIES AND EXPERIMENTAL APPLICATION ON SCIATIC NERVE

Fibrin glue is a natural, biocompatible and biodegradable topical tissue adhesive, resembling the final step of the coagulation cascade, it compose from cryoprecipitate and thrombin that form a fibrin clot by conversion of fibrinogen(in the cryoprecipitate ) to fibrin upon mixing these two components during application to the appliedsite. This glue has been used for many years in a wide range of clinical applications for suture support, tissue adhesion, and hemostasis. In contrast to some synthetic tissue adhesives, fibrin clots will be resorbed by the physiological process of fibrinolysis. Primarily, this process is induced by proteolytic cleavage and activation of plasminogen to plasmin. Premature lysis of fibrin glue is prevented by supplementation with fibrinolysis inhibitors like tranexamic acid. Platelets play important role in all stages of the physiological hemostasis, so to mimic this task and to use its biological characteristics; platelets were added to formula of the fibrin glue. The clinical performance of fibringlue is influenced by time need for clotting (important for manipulation of the field by the surgeon) and duration for clot lysis which should be delayed until wound healing, also the performanceis influenced by the biomechanical properties such as tensile strength and elasticity.The optimization of these parameters is important to both the manufacturers and surgeons. The aims of the study are: 1-Synthesis of the fibrin glue with different concentrations and additions(tranexamic acid and/ or platelets) with monitoring of clotting times and durations need for clot lysis. 2- Explore the biomechanical behavior to stretching (elasticity) and tension of the synthesized glue. 3-Animals' application to evaluate its clinical usefulness. Synthesis of the glue revealed significant increased clotting times and durations need for clot lysis when cryoprecipitate concentration was increased (had caused non significant decreased clotting time at optimized cryoprecipitate level) or when tranexamic acid and/or platelets were added. Theelasticity tests clarified that the increase of cryoprecipitateconcentration oraddition oftranexamic acidto fibrin glue formula had caused significant higher results, which decrease over time. On the other hand, platelets alone or in combination with tranexamic acid additionhad caused significant decrease elasticity results, which increase over time.
The tension tests revealed that the increase of cryoprecipitate concentration or additions of platelets alone or in combination with tranexamic acid had caused significant higher results, which decrease overtime,in contrast to the used oftranexamic acid addition, which caused significant decrease in tension results, thatdecreaseover time. A rat models with severed sciatic nerveswere employed to evaluate the clinical efficacy and usefulnessof the glue, the results showedgradual clinical improvement of the paralyzed legsin operated rats with symmetrical bilateral movements at 2 months duration. Use of the fibrin glue for suturing was easy, timesaving and without side effects or complications. in conclusion,increasecryoprecipitateconcentration and change in thetypeand theamount of additions(tranexamicacid and/orplatelets)hadcausedchanges in characteristics of thegluewhichshould be monitared and optimizedaccordingtotheneed of theapplicationfield.