Immunochemical analysis of polyspecific antibodies in patients exposed to bovine fibrin sealant

Intraoperative surgical sealant application during cardiac defect repair

Bleeding can occur as a sequela to cardiac surgery. Surgical products-such as conventional sutures and clips, and somewhat less conventional sealants-have been developed to prevent this event. Among these, CoSeal is a sealant used at our institution; here we report the cases of 2 patients in whom CoSeal was used successfully as either a supplement or an alternative to suture repair. This sealant was found to be useful in attaining hemostasis both in high-pressure ventricular repair and in the rupture of a friable coronary sinus adjacent to vital structures (in this instance, a left circumflex coronary artery).

Characterization of the biological effect of fish fibrin glue in experiments on rats: immunological and coagulation studies

Fibrin glues (FG) of human or bovine origin are widely used for haemostasis and wound healing. In addition FGs are studied in many biomedical areas like cell therapy or tissue engineering. As any mammalian plasma products FG-s pose risk of transmission of bacteria, viruses, or prions and may compromise patient homeostasis. In this study, we examined coagulation parameters and immunological status of rats treated with salmon-derived FG. We evaluated the changes in thrombin time, prothrombin activity, and presence of antibodies on 46 Wistar rats. This study shows that salmon-derived FG, injected intraperitoneally, does not cause coagulation disturbances in the peripheral blood. After a first challenge with salmon-derived FG there were low but detectable amounts of antibodies revealed by ELISA and immunoblot. After a second administration there was substantial elevation of antibodies to FG components and other copurifying plasma proteins. Antibody reactivity to human Factor Va, revealed in three animals, was not associated with FG application. Taken together, blood immunological and coagulation parameters support the suitability of salmon-derived FG in the development of fibrin sealants for medical use.

Hemostatic agents and tissue glues in urologic injuries and wound healing

Biosurgical preparations designed to promote surgical hemostasis and tissue adhesion are now available to the urologist and are increasingly being used across all surgical disciplines. Fibrin sealant and gelatin thrombin matrix are the two most widely used bio-surgical adjuncts in urology. Complex reconstructive, oncologic, and laparoscopic genitourinary procedures are those most appropriate for sealant use. This article details the diverse urologic applications of biosurgical products in the management of urologic injuries and the promotion of wound healing.

Fibrin Sealants and Glues

Fibrin sealants and fibrin glues have become effective instruments in the care of surgical patients. They have been used as an adjunct to hemostasis, wound healing, tissue adhesion, and drug delivery. In cardiac surgery, fibrin glues have emerged as valuable tools to improve hemostasis, decreased blood transfusions, improve tissue handling, and pretreat vascular grafts. Fibrin glues and sealants are now available commercially in the United States. This article will review the history, pharmacology, uses, and toxicity of fibrin sealants and fibrin glues.

Relative purity of thrombin-based hemostatic agents used in surgery

BACKGROUND

Hemostatic agents used in surgery contain thrombin isolated from either a bovine or human source. The use of thrombin derived from a bovine source has been associated with the development of an abnormal immune response, but a study of the immunoreactivity of the various commercially available thrombin preparations has not been conducted. This study determined the relative purity of commercially available thrombin preparations, if humans have natural antibodies that recognize these preparations, and if elicited antibodies against bovine thrombin cross-react with other bovine or human hemostatic agents.

STUDY DESIGN

The purity of hemostatic agents was determined by protein and substrate assays, electrophoresis, and immunoblotting. The natural antigenicity and cross-reactivity of elicited antibodies were measured by ELISA using serum samples from 82 donors from the Red Cross and serum collected from patients exposed to bovine thrombin, respectively.

RESULTS

All of the bovine thrombin preparations were found to contain the xenogeneic carbohydrate galactosealpha1-3galactose. The natural antigenicity of the bovine thrombin preparations was greater than that of a human thrombin preparation and similar to that of porcine aortic endothelial cells. Antibodies elicited against bovine thrombin were found to cross-react with other bovine preparations and other xenoantigens but not with human hemostatic preparations.

CONCLUSIONS

All patients have antibovine thrombin antibodies, even before exposure to bovine thrombin-containing hemostatic agents. The cross-reactivity of elicited antibovine thrombin antibodies indicates that if a patient has been sensitized to a bovine product, it is likely safer to use a human-derived product in lieu of a bovine product.

Antiphospholipid antibodies: discovery, definitions, detection and disease

Antiphospholipid antibodies (aPL) are immunoglobulins of IgG, IgM and IgA isotypes that target phospholipid (PL) and/or PL-binding plasma proteins. Detection of aPL in the laboratory is done currently by both immunoassays and functional coagulation tests. Convention defines aPL specificity in immunoassays according to the particular PL substrate present, for example aPS represents antiphosphatidylserine antibodies. This may be technically incorrect inasmuch as a particular PL may be responsible for binding and highly concentrating a specific plasma protein, the latter then becomes the target for the aPL. The binding of beta(2)GP-I (apolipoprotein H) to the negatively charged PL, cardiolipin (CL) provides a good example of this circumstance. In contrast, aPL which specifically prolong coagulation times in in vitro are called lupus anticoagulants (LA). The precise PL target(s) of the aPL responsible for LA activities are unknown and often debated. The persistent finding of aPL in patients in association with abnormal blood clotting and a myriad of neurological, obstetrical and rheumatic disorders often compounded by autoimmune diseases has led to an established clinical diagnosis termed antiphospholipid syndrome (APS). The common denominator for these APS patients is the presence of circulating aPL on two or more occasions and the observation of events attributable to abnormal or accelerated blood clotting somewhere in vivo. The purpose of this review is to collect, collate, and consolidate information concerning aPL.

Antiphospholipid antibodies after surgical exposure to topical bovine thrombin

Exposure to topical bovine thrombin during surgery frequently results in the development of antibodies to multiple protein and carbohydrate antigens. We investigated the frequency of increased levels of antibodies to cardiolipin and beta(2)-glycoprotein I (beta(2)-GPI) in two groups of patients, one exposed to bovine thrombin during cardiovascular surgery (n = 151) and a "control" group undergoing cardiovascular surgery but without exposure to bovine thrombin (n = 11). Anticardiolipin antibody levels were increased before surgery in 10 of the 151 patients exposed to topical thrombin (6.6%). Four to 8 weeks after surgery, 84 patients (55.6%) had increased anticardiolipin antibody levels (P <.0001). In the control group, an increased anticardiolipin antibody level was present in a single patient before and after surgery (9%). Increased levels of antibodies to bovine and human beta(2)-GPI were also observed after surgery in the patients exposed to topical thrombin (37.7% and 38.2%, respectively). Increased anticardiolipin levels correlated with higher levels of antibody to bovine, but not human, beta(2)-GPI. In addition, increased levels of anticardiolipin antibody were associated with higher levels of antibodies to bovine factor V and prothrombin, as well as human factor V. Antibody binding on an enzyme-linked immunosorbent assay conducted to detect anticardiolipin antibody was dependent on the presence of anionic phospholipid, indicating that binding was not linked to the fetal bovine serum in the blocking buffer alone. Seven of 8 patients with delayed thromboembolic complications had increased anticardiolipin IgG antibody levels after surgery, but this association was not statistically significant. Nevertheless, our findings support the recommendation that the clinical safety of these commonly used hemostatic agents should be reassessed.

Serological analysis of patients treated with a new surgical hemostat containing bovine proteins and autologous plasma

A randomized, controlled clinical study of the management of diffuse bleeding with CoStasis surgical hemostat, a new hemostat containing bovine thrombin and collagen with the patient's own plasma, included patients undergoing cardiac, hepatic, iliac, and general surgery. Sera from 92 patients treated with CoStasis and 84 control patients were collected preoperatively and at a post surgical follow-up of 8 weeks. Among the control group, 57 patients were treated with Instat collagen sponge in noncardiac indications. Results showed that antibody responses in the CoStasis clinical study were similar to the reported literature for all antigens screened and were not associated with any adverse reactions. The bovine thrombin preparations in CoStasis and other commercially available thrombins were compared with the use of SDS-PAGE and Western blot analyses. Within this clinical study, CoStasis was shown to be a safe and effective hemostatic product containing bovine thrombin and bovine collagen and no pooled human blood products.

Exposure of mice to topical bovine thrombin induces systemic autoimmunity

Bovine thrombin is used as an aid to hemostasis in medical and surgical procedures. At least 500,000 Americans are exposed to this therapeutic annually and reports suggest that exposure is associated with the development of autoreactive antibodies. To determine whether bovine thrombin can induce pathological autoimmunity we exposed nonautoimmune-prone galactose-alpha1-3-galactose-deficient mice to the two bovine thrombin preparations currently approved for use in the United States. We found that, like humans exposed to bovine thrombin, mice developed an immune response against the therapeutic and the xenogeneic carbohydrate galactose-alpha1-3-galactose, and some mice developed autoantibodies against clotting factors. Further, unexpectedly, a single exposure to this therapeutic also induced autoimmunity with features characteristic of systemic lupus erythematosus including antibodies against nuclear antigens, native DNA, double-stranded DNA, and cardiolipin. High levels of these autoantibodies correlated with glomerulonephritis in all mice evaluated. This autoimmune syndrome was detected in mice 15 weeks after a secondary exposure to bovine thrombin and female mice were found to develop the syndrome at a significantly greater frequency than males. Thus, these studies indicate that exposure to bovine thrombin preparations can induce a pathological systemic autoimmune syndrome with lupus-like serology.

Antiphospholipid antibodies. Risk assessments for solid organ, bone marrow, and tissue transplantation

The literature pertaining to transplantation of solid organs, bone marrow, and other tissues in aPL-positive patients has been reviewed. The effects that aPL have relative to BMT are altogether different than those ascribed to solid organs and tissues. By definition, the transplantation of allogeneic bone marrow serves to reconstitute the recipient with a completely new and genetically different repertoire of antibody-producing cells. Previously aPL-positive bone marrow recipients become aPL-negative subsequent to transplantation assuming that the marrow donor is aPL-negative. These observations are the basis for contemporary experimental approaches to curing certain autoimmune diseases with BMT. Similarly, it would follow that an aPL-negative patient provided cells from an aPL-positive donor could become aPL-positive and suffer increased risk for thrombosis. From the data provided in most of the non-bone marrow publications, the presence of aPL should be considered a grave risk factor for any potential solid organ or tissue transplant candidate. Peritoneal dialysis patients seem to be at maximal risk. Given the serious emotional and economic impact of irreversible thrombotic loss suffered by organ transplant recipients, these factors alone should justify the modest expense of pretransplant aPL screening. In the United States, the average cost of losing a kidney transplant to aPL-associated thrombosis was estimated from 1996 data to be $82,000. The cost of losing a heart or liver is measured not only in dollars but often in the patient's life. The encouraging news, however, is that once aPL are identified before transplantation, prophylactic anticoagulation seems to be capable of forestalling untoward aPL-associated allograft events. Clearly, much remains to be discovered in exploring the pathobiologic characteristics of aPL in the laboratory as well as in neutralizing their procoagulant effects at the bedside.