Histopathology of Lesions in Swine Exposed to a Hemostatic Bandage Composed of Salmon Thrombin and Fibrinogen

Abstract : Hemostatic bandages composed of salmon thrombin and fibrinogen are very effective in stopping bleeding in a swine aortal injury model. However, because of concern that these foreign proteins may induce an immune response in the patients, we investigated the inflammatory response in pigs exposed to salmon thrombin/fibrinogen dressings. Two defined full-thickness skin lesions were surgically created on the backs of 25kg Yorkshire swine and one lesion was treated with a salmon protein-based dressing and the other with a control commercially-available pad. Animals were sacrificed at seven or twenty-one days and the lymphoid organs harvested for histopathological examination. The 21-day animals were given an additional boost of salmon thrombin/fibrinogen to simulate a second bandage application. Examination of the histology showed a cellular inflammatory response in treated and untreated animals that resolved by the 21-day stage. Lymph node and spleen samples showed germinal center formation in follicles, but the activity levels were higher in organs on the untreated side. Blood samples taken to assay for antibodies showed antibodies formed at low titers that recognized salmon fibrinogen and, following the booster shot, salmon thrombin.