Australian Brown Snake Pseudonaja Textilis Research Articles

Hemostatic properties of a venomic protein in rat organ trauma

Previous in vitro work characterized the protease Q8009 isolated from the venom of the Australian brown snake Pseudonaja textilis textilis with Factor Xa-like activity and hemostatic properties. The purpose of the work described here characterizes the in vivo hemostatic properties in a rat model of parenchymatous organ injury. The key parameters of activity included reduction in time-to-hemostasis and total volume of blood loss in spleen, liver and kidney wound models in rats. The surgical protocols involved exposure of the organs via a midline abdominal laparotomy. Using a clean metal template with 6, 6.5, 9 mm holes for spleen, liver and kidney, respectively, a predetermined volume of the organ was gently extruded through the template hole and excised with a razor blade. About 50 to 75 μL of collagen matrix with the different test solutions was applied to the wounds. Blood was collected and at the end of the procedure animals were humanely sacrificed with an anesthetic overdose. Determination of blood was performed using the hematin assay using a standard curve. Blood loss per minute and total blood loss were calculated. Results from the studies demonstrated that the application of Q8009 and collagen matrix to surgical wounds significantly reduced the total amount of blood loss and the time-to-hemostasis. In the spleen wound model, Q8009 at 100, 250 and 1000 μg/ml significantly reduced ( p < 0.001) the total volume of blood lost relative to thrombin and reduced the time-to-hemostasis by 25-50%, as compared to 7% by thrombin. In the liver wound model, Q8009 at 250 and 1000 μg/ml significantly reduced ( p < 0.001) the total volume of blood lost relative to thrombin and reduced the time-to-hemostasis from 10.5 min by thrombin to 5.6 min with Q8009. In the kidney wound model, Q8009 at 250 μg/ml significantly reduced ( p < 0.05) the total volume of blood lost and reduced the time-to-hemostasis by 25% when compared to thrombin. The hemostasis levels were consistent with previous findings in skin wound rat models where Q8009 consistently reduced the total volume of blood lost and shortened time-to-hemostasis. Application of Q8009 plus collagen matrix significantly reduced the volume of total blood loss and time-to-hemostasis in rat surgical organ wound models induced bleeding, as compared to a commercially available hemostat device. The protein Q8009 has greater capacity to reduce blood loss and shorten time-to-hemostasis; highly desirable properties where rapid hemostasis is needed in surgical wounds in parenchymatous organs.

Hemostatic Properties of a Venomic Protein (Q8009) in Rodent Organ Injuries

Previous in vitro work characterized the protease Q8009 from the venom of the Australian brown snake Pseudonaja textilis textilis with hemostatic properties and Factor Xa-like activity. In vivo studies indicate that Q8009 applied to surgical injury sites is superior to thrombin in blood loss reduction and time-to-hemostasis. The spleen, liver and kidney protocols involved excision of a predetermined portion of the organ and the application of 50 to 75 μL of collagen matrix and test solutions. Blood was collected for 12 one-minute intervals and blood loss measured by hematin determination. In the spleen excision model, Q8009 at 100, 250 and 1000 μg/ml significantly reduced (p<0.001) total volume of blood lost, relative to thrombin and reduced time-to-hemostasis between 25–50%, as compared to 7% by thrombin. In the liver excision model, Q8009 at 250 and 1000 μg/ml significantly reduced (p<0.001) total volume of blood lost, relative to thrombin and reduced time-to-hemostasis from 10.5 minutes by thrombin to 5.6 minutes with Q8009. In the kidney excision model, Q8009 at 250 μg/ml significantly reduced (p<0.05) total volume of blood lost, relative to thrombin and reduced time-to-hemostasis by 25% when compared to thrombin. Therefore, application of Q8009 to injured organs significantly reduced total blood loss and shortened the time-to-hemostasis, when compared to thrombin. This work was supported by QRxPharma.

Hemostatic Properties of Topically Applied Q8009 a Snake Venom Protease

Previous in vitro work characterized the protease Q8009 from the venom of the Australian brown snake Pseudonaja textilis textilis with hemostatic properties and Factor Xa-like activity. In vivo studies reported herein indicate that Q8009 mixed with collagen matrix and applied to surgical injury sites is superior to thrombin in blood loss reduction and a shorter time-to-hemostasis. The dermal injury model involved a dermal incision (1 mm deep x 5 mm in length) on each hind limb manus between digits 2 and 3. The tail-tip model utilized transection of the last 2 mm of the tail-tip. Blood was collected for 12 one-minute intervals or until hemostasis, and blood loss was measured by quantifying hematin concentration. In the dermal injury model, Q8009 at concentrations of 100 [mu]g/mL, 250 [mu]g/mL and 1,000 [mu]g/mL significantly reduced (p<0.001) blood loss, compared to thrombin and reduced the time-to-hemostasis to ~ 2.0 minutes compared to 4.77 minutes with thrombin. In the tail-tip transection model, Q8009 and collagen matrix did not significantly reduce blood loss relative to thrombin. However, Q8009 (1,000 [mu]g/mL) without collagen matrix, significantly reduced (p<0.001) blood loss from the tail wound. When the Tail-Tip and Dermal models were averaged together, thrombin reduced overall blood loss by 72%, Q8009 at 100 [mu]g/mL, 250 [mu]g/mL and 1,000 [mu]g/mL reduced blood loss by 75%, 90% and 83%, respectively. Therefore, topical application of Q8009 significantly reduced total blood loss and shortened the time-to-hemostasis, when compared to thrombin. This work was supported by QRxPharma.