Effect of Hemocoagulase on the Prevention of Bleeding after Percutaneous Renal Biopsy.

A percutaneous renal biopsy is an essential tool for the diagnosis of various renal diseases; however, post-biopsy bleeding is a major complication. Hemocoagulase is a detoxified and purified snake venom enzyme that is widely used to prevent post-procedural bleeding. In this study, we retrospectively analyzed the effect of hemocoagulase on post-renal biopsy bleeding. We included 221 patients who underwent percutaneous renal biopsy between April 2017 and December 2020 and analyzed post-renal biopsy hemoglobin (Hb) decline in patients who were administered a periprocedural hemocoagulase injection. After the renal biopsy, the mean Hb decrease in the entire patient cohort was 0.33 ± 0.84 g/dL. Periprocedural hemocoagulase injection lowered the Hb decline post-renal biopsy (0.50 ± 0.87 vs. 0.23 ± 0.80 g/dL, p = 0.0204). The propensity-matched cohort was also adjusted for factors influencing postprocedural bleeding; periprocedural hemocoagulase injection reduced the Hb decline post-renal biopsy (0.56 ± 0.89 vs. 0.17 ± 0.74 g/dL, p = 0.006). There were no adverse events (e.g., thrombosis and anaphylactic shock) due to hemocoagulase. Our study demonstrated the beneficial effect of hemocoagulase on post-renal biopsy Hb decline, suggesting its clinical value in preventing post-renal biopsy bleeding.

Acute and repeated dose (28 days) toxicity studies in rats and dogs of recombinant batroxobin, a snake venom thrombin-like enzyme expressed from Pichia pastoris.

Recombinant batroxobin is a thrombin-like enzyme of Bothrops atrox moojeni venom. To evaluate its toxicological effect, it was highly expressed in Pichia pastorisand successfully purified to homogeneity from culture broth supernatant following Good Manufacturing Practice (GMP). The maximum tolerated dose of the recombinant batroxobin was examined in Sprague-Dawley (SD) rat and Beagle dogs following Good Laboratory Practice (GLP) regulations. The approximate lethal dose of recombinant batroxobin was 10 National Institute of Health (NIH) u/kg in male and female rats. Slight test substance-related effects were clearly in male and female dogs at more than 10 NIH u/kg. The maximum tolerated dose (MTD) was considered to be greater than 30 NIH u/kg in dogs. To investigate the repeated dose toxicity of batroxobin, the test item was intravenously administered to groups of SD rat and Beagle dog every day for 4 weeks. We observed that all animals survived the duration of the study without any effects on their mortality. There were no effects in both rats and dogs regarding their clinical signs, body weight, food consumption, ophthalmological examination, urinalysis, hematology, clinical chemistry, organ weightand gross post mortem examinations. The no adverse effect level (NOAEL) of recombinant batroxobin for both males and females is considered to be greater than 2.5 NIH u/kgin rats and 1 NIH u/kg in dogs, respectively. No toxic effects were noted in target organs. In conclusion, these results show a favorable preclinical profile and may contribute clinical development of recombinant batroxobin.

Feasibility of treating hyperfibrinogenemia with intermittently administered batroxobin in patients with ischemic stroke/transient ischemic attack for secondary prevention.

This study evaluated the safety and efficacy of batroxobin in treating hyperfibrinogenemia for secondary stroke prevention. Patients with ischemic stroke or transient ischemic attack (TIA) were measured for plasma fibrinogen levels. Selected participants had concomitant hyperfibrinogenemia (plasma fibrinogen > or = 3.0 g/l). Patients enrolled between 1 July 2003 and 31 December 2004 were treated with batroxobin; patients enrolled between 1 January 2002 and 30 June 2003 were treated without batroxobin. Batroxobin was administered intermittently via intravenous injection at 3-monthly intervals. Patients in both groups were followed for 1 year. Any cerebrovascular events and suspected adverse events were recorded. In total, 112 ischemic stroke/TIA patients with concomitant hyperfibrinogenemia were enrolled, 52 being treated with batroxobin and 60 without batroxobin. Six patients (11.5%) with batroxobin and 16 patients (26.7%) without batroxobin had recurrent cerebral ischemic events during follow-up. Stroke/TIA recurrence in patients without batroxobin was higher than that in patients with batroxobin (P < 0.05). Two patients with batroxobin and two patients without batroxobin developed hemorrhagic stroke during follow-up. There were five deaths (9.6%) in the batroxobin group, and seven deaths (11.7%) in the nonbatroxobin group during follow-up (P > 0.05). Intermittent intravenous injection of batroxobin can efficiently reduce the risk for stroke/TIA recurrence in patients with concomitant hyperfibrinogenemia.

Demonstration of enhanced endogenous fibrinolysis in thrombin activatable fibrinolysis inhibitor-deficient mice.

To investigate the importance of thrombin activatable fibrinolysis inhibitor (TAFI) in the stabilization of plasma clots, we have compared fibrinolysis in TAFI-deficient (KO) and wild-type (WT) littermate mice. TAFI-deficient mice were previously generated by targeted gene disruption. The level of TAFI activity generated in plasma from WT mice in the presence of added thrombin and thrombomodulin (activatable TAFI) is twice that of plasma from TAFI heterozygous mice (HET); no activatable TAFI is detected in TAFI KO plasma. In vitro, TAFI KO plasma clots lysed faster than WT plasma clots, and HET plasma clots lysed at an intermediate rate. The rate of clot lysis for KO mice is not changed in the presence of potato carboxypeptidase inhibitor, a specific inhibitor of TAFIa, whereas the WT and HET clot lysis rates are increased in the presence of potato carboxypeptidase inhibitor. C-terminal lysine residues are preserved on partially degraded clots from KO mice, but are absent from partially degraded WT clots. In vivo, in a batroxobin-induced pulmonary embolism model, KO mice displayed a lower retention of fibrin in the lungs than did WT mice. These results are the first demonstration of enhanced endogenous fibrinolysis in an in vivo model without the addition of exogenous thrombolytic.

Efficacy of intravitreal hemocoagulase for control of bleeding in rabbit experimental model of vitrectomy.

Hemorrhage during vitrectomy for diabetic retinopathy or in the recently traumatized eye can complicate the surgical procedures and might cause termination and failure of vitrectomy in some cases. The effect of the hemocoagulase, Botropase, on the hemostasis of intraocular bleeding was evaluated in a rabbit model by cutting central retinal vessels in the medullary ray. Addition of the hemocoagulase (1 NIH unit/100 ml) to BSS Plus significantly reduced bleeding time. Immediately after vitrectomy with the use of this hemocoagulase, the average of the maximum amplitudes of the b-wave in electroretinography was normal, although the sensitivity of the electroretinogram was reduced by 0.1 log unit in the experimental eyes which were infused with hemocoagulase solution. The sensitivity showed no significant difference after the second postoperative day. The experimental eyes showed no abnormal findings histologically. Infusate containing Botropase appeared to be a useful adjunct for the control of intraocular bleeding during vitreous surgery.

Systemic haemorrhage in rats induced by a haemorrhagic fraction from Bothrops jararaca venom.

The main haemorrhagic fraction of Bothrops jararaca venom, showing in vitro fibrinogenolytic activity and an inhibitory effect on platelets aggregation induced by collagan, was studied in rats. Development of coagulopathy and/or haemorrhage was studied 2 hr after s.c. injection of batroxobin, B. jararaca whole venom and its haemorrhagic fraction. Incoagulable blood, together with low fibrinogen levels, were found only in rats injected with batroxobin and whole venom; thrombocytopenia alone was detected in rats given s.c. injections of haemorrhagin. Intravenous injection of low doses of haemorrhagin (less than 15 micrograms) resulted in significant thrombocytopenia, without any alterations in the blood coagulation mechanism. Severe damage to the vascular endothelium and skeletal muscle following s.c. injection of haemorrhagin together with signs of systemic haemorrhage in the kidneys, lungs and liver occurred. Levels of factor VIII and von Willebrand factor antigen were within the normal range in all animals. Serum levels of both whole venom and haemorrhagin were significantly correlated. This study confirms that B. jararaca haemorrhagin plays a vital role in systemic bleeding.