Purification of salmon clotting factors and their use as tissue sealants

Fibrin sealant prepared from the blood of farmed Atlantic salmon (Salmo salar) represents a potential source of well-controlled natural material with utility in a variety of clinical settings. A potential advantage of this material is a lower probability of viral or bacterial infection that has limited general approval of fibrin glues made from human or bovine proteins. This report describes the purification of fibrinogen from salmon blood, the use of fibrin glues derived from this material to promote wound healing in rats, and the antigenic response to this material. While the low ambient temperature of these cold water fish significantly lessens the probability of infectious transmission to humans, fibrinogen and factor XIII derived from S. salar are activated by human thrombin at 25 degrees C and 37 degrees C to form clots equivalent to those formed by human fibrin. We compare the reactivity of salmon and human fibrinogen with human and bovine thrombin and the structure and viscoelastic properties of the resulting fibrin gels over a range of pH and salt concentrations. The efficacy of salmon fibrin glues in a wound healing assay and the low antigenic response to salmon fibrinogen suggest that this material may substitute for proteins derived from mammalian sources with lower probability of infections.

Intensive blood and plasma exchange for treatment of coagulopathy in meningococcemia

Eight pediatric patients with fulminant meningococcemia, purpura, and disseminated intravascular cogulation who by multiple prognostic scoring systems were anticipated to have a poor outcome underwent intensive plasma exchange (IPE) or whole blood exchange (WBE) in addition to standard medical therapy. IPE/WBE was initiated shortly after admission with a mixture of both fresh frozen plasma and cryoprecipitate as the replacement solution. All IPE procedures were performed using a continuous flow system and a red cell prime. The mean fibrinogen level increased from 62 to 192 mg/dl, the prothrombin time (PT) decreased from a mean of 32.4 seconds to 15.1 seconds, and the mean activated partial thromboplastin time (APTT) decreased from 89.5 seconds to 40.1 seconds following completion of the initial IPE/WBE. There was a corresponding improvement in all coagulation factor levels but only slight improvement in antithrombin III (ATIII) and protein C levels. Seven of eight patients survived (87.5%) their initial presentation with the sole early death attributed to meningitis with cerebral edema. Mean fluid balance after the procedure was +10.8 +/- 5.87 cc/kg. There were no significant bleeding or cardiovascular complications during the procedure. There was no clinical or radiographic evidence of fluid overload after the procedure. This experience demonstrates that IPE/WBE may be conducted safely in critically ill, unstable pediatric patients and is effective in rapidly improving coagulopathy without fluid overload.

Autosomal recessive transmission of hemophilia A due to a von Willebrand factor mutation

The differential diagnosis of the genetic bleeding disorders, hemophilia A and von Willebrand disease, is occasionally confounded by the close molecular relationship of coagulation factor VIII and von Willebrand factor (vWF). This report describes the autosomal inheritance of a hemophilia A phenotype due to a mutation of vWF that results in defective factor VIII binding. The proband was a female patient with low levels of factor VIII activity. Polymerase chain reaction (PCR) amplification and DNA sequencing were employed to examine exons encoding the putative factor VIII binding domain of vWF. The patient was found to be homozygous for a single point mutation causing a Thr-->Met substitution at amino acid position 28 in the mature vWF subunit. The phenotypic expression of the mutation was determined to be recessive because heterozygous family members were clinically unaffected. Recombinant vWF containing the observed amino acid substitution was expressed in COS-1 cells. The mutant vWF was processed and secreted normally, and was functionally equivalent to wild-type vWF in its ability to bind to platelets. However, the mutant failed to bind factor VIII, demonstrating that the mutation was functionally related to the observed hemophilia phenotype. The family we describe demonstrates the recessive inheritance of a recently recognized class of genetic bleeding disorders, we call "autosomal hemophilia." We conclude that vWF mutation may be an under recognized cause of hemophilia, especially in cases where the inheritance pattern is not consistent with X-linked transmission.