Use of fibrin glue in sucrose gap method

Isolated frog nerves or rabbit sinus node strips were mounted in a single sucrose gap chamber. A fibrin glue Tissucol was used in this arrangement as an intercompartment seal. Under such conditions, the specimens produced stable trans-gap action potentials of relatively high amplitude. In other experiments the gap was filled with fibrin in place of sucrose solution. The results obtained in the fibrin gap experiments resembled these mentioned above.     

Salmon fibrin glue in rats: Antibody studies

Fibrin sealants and topical thrombin preparations are often used for haemostatic and sealing applications in clinical practice. Some of these preparations contain coagulation factors from bovine sources. To minimize the risk of infection and immunogenicity connected with mammalian blood products, proteins derived from the plasma of farmed Atlantic salmon have been considered as an alternative to these mammalian sources. The purpose of this study is to characterize the immunogenicity of salmon fibrin glue in an animal model focusing on crossreactivity of IgG antibodies to host endogenous counterparts. After two immunizations with salmon fibrin glue, rats developed antibodies of IgG and IgM type to both fibrin glue components. Weak crossreactivity to endogenous fibrinogen and thrombin was seen in a subset of rats after the second application of salmon proteins. Coagulation tests showed that salmon fibrin application has no effect on coagulation profiles in mammalian hosts, consistent with previous reports that found no evidence of significant crossreactivity with host proteins. These studies support the potential suitability of salmon fibrin glue for the development of preparations with clinical impact. Before human use can be considered, however, additional data about safety of this preparation in other animal models, including large animal studies, should be obtained.     

Experimental and clinical applications of fibrin glue

A 2-year experience with laboratory and clinical applications of fibrin glue is presented. An autologous technique, which eliminates the danger of multidonor preparations, has been developed in our blood bank. While one can obtain different fibrinogen concentrations from the same amount of a patient's blood, in vitro mechanical testing demonstrated that at higher fibrinogen concentrations there is an increase in shear adhesive strength. Evaluation of skin-graft take in 16 Sprague-Dawley rats did not demonstrate significant differences in healing when adhesive use was compared with suture technique. In a clinical study, four different groups of patients (facial burns, hand burns, difficult graft sites, and miscellaneous surgical applications) benefited from autologous or single-donor fibrin glue for a total of 82 cases. There are several distinct advantages to the use of fibrin adhesive: The autologous technique eliminates the risk of transmissible viral diseases (AIDS, hepatitis); it can be used as a sealant in the treatment of seromas, dural leaks, and lymphoceles; and it improves hemostasis and early graft adherence. Face and hands are resurfaced with sheet grafts in a single procedure, obtaining a better aesthetic result with complete graft take and immediate start of physical therapy. Neither sutures nor pressure dressings are required. The minimal postoperative care associated with early return to normal activities seems to increase the satisfaction of patients and nurse personnel.     

The use of aerosolized fibrin glue in face-lift surgery

The purpose of this study was to report the use of aerosolized fibrin glue in face-lift surgery. A prospective study was conducted of 48 patients undergoing face-lift surgery sequentially assigned into two groups. The first 24 patients underwent face lifts without glue and the next 24 patients with the use of aerosolized fibrin glue. One surgeon (J.P.F.) performed all the face lifts using the same technique. Drains were only used in those patients who did not receive fibrin glue. The amount of bruising and edema was compared in the two groups, as was the incidence of complications, such as hematomas. Operating time was also assessed in the two groups. The patients in whom glue was used had significantly less bruising and swelling (p < 0.0001), with a more rapid healing response. The risk of hematoma was also less with the use of glue (0 percent) than without glue (8.3 percent), but this was not statistically significant (p = 0.489). Another benefit was that drains were not needed when glue was used. Operating times were shorter by 13.3 minutes with the use of glue (p < 0.0001). Aerosolized fibrin glue has great promise in improving face-lift results, with excellent outcomes and fewer complications. The added cost of the glue is partially offset by an expedited patient recovery period without the need for drains.     

Evaluation of fibrin glue in rat sciatic nerve repairs

Using the rat sciatic nerve model, we evaluated the merits of homologous fibrin glue in the repair of peripheral nerve transections as compared to standard epineural suture repairs. A total of four study groups were used, with 10 animals assigned to each group. In group I, the transected sciatic nerve was repaired with six interrupted 10-0 nylon sutures; in group II, only two interrupted sutures were used; in group III, a two-suture repair was reinforced with fibrin glue; and in group IV, only fibrin glue was used. All animals were sacrificed at 8 weeks, and histologic sections evaluated. When fibrin alone was used, dehiscence occurred in 80 percent of the animals, and as reinforcement of a two-suture repair, it only increased the inflammatory reaction.     

Chondrocyte aggregation in suspension culture is GFOGER-GPP- and beta1 integrin-dependent

Isolated chondrocytes form aggregates in suspension culture that maintain chondrocyte phenotype in a physiological pericellular environment. The molecular mechanisms involved in chondrocyte aggregation have not been previously identified. Using this novel suspension culture system, we performed mRNA and protein expression analysis along with immunohistochemistry for potential cell adhesion molecules and extracellular matrix integrin ligands. Inhibition of aggregation assays were performed using specific blocking agents. We found that: (i) direct cell-cell interactions were not involved in chondrocyte aggregation, (ii) chondrocytes in aggregates were surrounded by a matrix rich in collagen II and cartilage oligomeric protein (COMP), (iii) aggregation depends on a beta1-integrin, which binds a triple helical GFOGER sequence found in collagens, (iv) integrin alpha10-subunit is the most highly expressed alpha-subunit among those tested, including alpha5, in aggregating chondrocytes. Taken together, this body of evidence suggests that the main molecular interaction involved in aggregation of phenotypically stable chondrocytes is the alpha10beta1-collagen II interaction.     

Injectable tissue-engineered cartilage using a fibrin glue polymer.

The purpose of this study was to demonstrate the feasibility of using a fibrin glue polymer to produce injectable tissue-engineered cartilage and to determine the optimal fibrinogen and chondrocyte concentrations required to produce solid, homogeneous cartilage. The most favorable fibrinogen concentration was determined by measuring the rate of degradation of fibrin glue using varying concentrations of purified porcine fibrinogen. The fibrinogen was mixed with thrombin (50 U/cc in 40 mM calcium chloride) to produce fibrin glue. Swine chondrocytes were then suspended in the fibrinogen before the addition of thrombin. The chondrocyte/polymer constructs were injected into the subcutaneous tissue of nude mice using chondrocyte concentrations of 10, 25, and 40 million chondrocytes/cc of polymer (0.4-cc injections). At 6 and 12 weeks, the neocartilage was harvested and analyzed by histology, mass, glycosaminoglycan content, DNA content, and collagen type II content. Control groups consisted of nude mice injected with fibrin glue alone (without chondrocytes) and a separate group injected with chondrocytes suspended in saline only (40 million cells/cc in saline; 0.4-cc injections). The fibrinogen concentration with the most favorable rate of degradation was 80 mg/cc. Histologic analysis of the neocartilage showed solid, homogeneous cartilage when using 40 million chondrocytes/cc, both at 6 and 12 weeks. The 10 and 25 million chondrocytes/cc samples showed areas of cartilage separated by areas of remnant fibrin glue. The mass of the samples ranged from 0.07 to 0.12 g at 6 weeks and decreased only slightly by week 12. The glycosaminoglycan content ranged from 2.3 to 9.4 percent for all samples; normal cartilage controls had a content of 7.0 percent. DNA content ranged from 0.63 to 1.4 percent for all samples, with normal pig cartilage having a mean DNA content of 0.285 percent. The samples of fibrin glue alone produced no cartilage, and the chondrocytes alone produced neocartilage samples with a significantly smaller mass (0.47 g at 6 weeks and 0.46 g at 12 weeks) when compared with all samples produced from chondrocytes suspended in fibrin glue (p < 0.03). Gel electrophoreses demonstrated the presence of type II collagen in all sample groups. This study demonstrates that fibrin glue is a suitable polymer for the formation of injectable tissue-engineered cartilage in the nude mouse model. Forty million chondrocytes per cc yielded the best quality cartilage at 6 and 12 weeks when analyzed by histology and content of DNA, glycosaminoglycan, and type II collagen.     

Chondrocyte transplantation for osteochondral defects with the use of suspension culture

Cartilage graft is considered to be useful in repairing chondral or osteochondral defects. One method of the cartilage graft is achieved by autologous chondrocyte transplantation following cell culture. However, chondrocytes change their phenotype during culture. We used costal chondrocytes cultured over agarose (suspension culture) as a source of graft materials. The suspension-cultured chondrocytes formed aggregate in culture. We first examined the expressions of cartilage-specific matrices of cultured chondrocytes after two weeks in culture. The chondrocytes cultured over agarose expressed more type II collagen mRNA than those cultured on plastic dishes did after two weeks in culture. Safranin O staining showed the presence of glycosaminoglycans in the chondrocyte culture over agarose, while glycosaminoglycans were not observed in the culture on plastic dishes. We then examined the changes of rat articular osteochondral defects after transplantation of suspension-cultured chondrocytes. The aggregate of suspension-cultured chondrocytes was easily picked up with forceps and transplanted in the osteochondral defects. The defects were filled with safranin O-stained hyaline cartilage tissue two weeks after chondrocyte transplantation. On the contrary, the fibrous materials, which were not stained with safranin O, were observed in the control defects. These results suggest that the suspension-cultured chondrocytes are useful for autologous cartilage grafts by preserving chondrocyte phenotype.     

The effect of fibrin glue on skin grafts in infected sites.

Fibrin bonding of skin grafts to wounds is an essential part of the graft-adherence process. Bacteria, in concentrations greater than 10(5)/gm of tissue, are associated with graft failure. Sixty-five rats were randomly divided into three groups, dorsal split-thickness skin grafts were harvested, and the sites were inoculated with Staphylococcus aureus. After incubation, each wound was quantitatively biopsied and treated with saline, fibrin glue with aprotinin, or fibrin glue alone. We found that the addition of commercially available fibrin glue with or without the antifibrinolytic agent aprotinin is capable of restoring graft adherence to normal levels in graft sites infected with greater than 10(5) bacteria/gm of tissue. Fibrin glue may have potential for increasing skin-graft take in the clinical situation where the graft bed is infected.