The Efficacy of Fibrinogen Concentrates in Relation to Cryoprecipitate in Restoring Clot Integrity and Stability against Lysis.

Loss of fibrinogen is a feature of trauma-induced coagulopathy (TIC), and restoring this clotting factor is protective against hemorrhages. We compared the efficacy of cryoprecipitate, and of the fibrinogen concentrates RiaSTAP® and FibCLOT® in restoring the clot integrity in models of TIC. Cryoprecipitate and FibCLOT® produced clots with higher maximal absorbance and enhanced resistance to lysis relative to RiaSTAP®. The fibrin structure of clots, comprising cryoprecipitate and FibCLOT®, mirrored those of normal plasma, whereas those with RiaSTAP® showed stunted fibers and reduced porosity. The hemodilution of whole blood reduced the maximum clot firmness (MCF) as assessed by thromboelastography. MCF could be restored with the inclusion of 1 mg/mL of fibrinogen, but only FibCLOT® was effective at stabilizing against lysis. The overall clot strength, measured using the Quantra® hemostasis analyzer, was restored with both fibrinogen concentrates but not cryoprecipitate. α2antiplasmin and plasminogen activator inhibitor-1 (PAI-1) were constituents of cryoprecipitate but were negligible in RiaSTAP® and FibCLOT®. Interestingly, cryoprecipitate and FibCLOT® contained significantly higher factor XIII (FXIII) levels, approximately three-fold higher than RiaSTAP®. Our data show that 1 mg/mL fibrinogen, a clinically achievable concentration, can restore adequate clot integrity. However, FibCLOT®, which contained more FXIII, was superior in normalizing the clot structure and in stabilizing hemodiluted clots against mechanical and fibrinolytic degradation.

Partial purification and identification of a metalloproteinase with anticoagulant activity from Rhizostoma pulmo (Barrel Jellyfish).

Rhizostoma pulmo (Barrel Jellyfish) is one of the commonly found jellyfishes on the South-Goan coast of India. Here we present characterization of R. pulmo tentacle extract. The tentacle extracts were found to be capable of affecting the hemostatic system at three different levels, as it exhibited fibrinogenolysis, fibrinolysis and inhibition of ADP induced platelet aggregation. It preferentially cleaved the Aα chain of fibrinogen, followed by the Bß chain and the γ chain. The tentacle extract also showed significant hemolytic activity against human RBCs and strong proteolytic activity for substrates like (azo) casein and gelatin. However, this proteolytic activity was completely inhibited by EDTA (metalloproteinase inhibitor) but not by PMSF (serine proteinase inhibitor). The extract was devoid of phospholipase activity. A semi-purified protein possessing fibrinogenolytic activity was obtained by a combination of ammonium sulphate precipitation and size exclusion HPLC. Atomic absorption analysis of this protein indicated presence of Zn2+ and treatment with metalloproteinase inhibitor caused complete loss of activity. A 95 kDa metalloproteinase was identified in this fraction and was named Rhizoprotease. Protein Mass Fingerprinting of Rhizoprotease indicates it to be a novel protein.

Anticoagulant activity of Moon jellyfish (Aurelia aurita) tentacle extract.

Moon jellyfish (Aurelia aurita) tentacle extract was studied for its anticoagulant activity in vitro. The Jellyfish Tentacle Extract (JFTE) showed very strong fibrinogenolytic activity by cleaving Aα and Bß chain of fibrinogen molecule. The fibrinogenolytic activity was found to be stronger than some snake venom derived anticoagulants. JFTE also completely liquefied fibrin clots in 24 h. JFTE was found to contain both high and low molecular weight proteins/peptides. The fibrinogenolysis appears to be caused by high molecular weight fractions of the extract. It has been also noted that PMSF significantly reduced fibrinogenolytic activity and heating totally abolished it. Autolytic degradation of the high molecular weight protein was also noted. Autolysis slowed down, but did not abolish the fibrinogenolytic activity of the extract.