Identification of a novel thrombin-like phospholipase A2 from Gloydius ussuriensis snake venom

Clinical implications of coagulotoxic variations in Mamushi (Viperidae: Gloydius) snake venoms

Snake bite is currently one of the most neglected tropical diseases affecting much of the developing world. Asian pit vipers are responsible for a considerable amount of envenomations annually and bites can cause a multitude of clinical complications resulting from coagulopathic and neuropathic effects. While intense research has been undertaken for some species of Asian pit viper, functional coagulopathic effects have been neglected for others. We investigated their effects upon the human clotting cascade using venoms of four species of Gloydius and Ovophis okinavensis, a species closely to Gloydius. All species of included within this investigation displayed varying fibrinogenolytic effects, resulting in a net anticoagulant outcome. Gloydius saxatilis and Gloydius ussuriensis displayed the most variable effects from differing localities, sampled from Russia and Korea. As this Gloydius investigation includes some geographical variation, notable results indicate key variations of these species that point to possible limitations in antivenom cross-reactivities, which may have implications for the clinical care of victims envenomed by these snakes.

Carbon monoxide inhibits the anticoagulant activity of phospholipase A2 purified from Crotalus adamanteus venom

Snake venom contains a myriad of classes of enzyme which have been investigated for medicinal and toxinological purposes, including phospholipase A₂ (PLA₂), which is responsible for anticoagulant, myotoxic and neurotoxic effects. Given the importance of PLA₂, the purposes of the present investigation were to characterize the coagulation kinetic behavior of a PLA₂ purified from Crotalus adamanteus venom (Ca-PLA₂) in human plasma with thrombelastography and determine if carbon monoxide could inhibit its activity. Coagulation kinetics were determined in human plasma with a range of Ca-PLA₂ activity (0-2 U/ml) via thrombelastography. Then, using carbon monoxide releasing molecule-2 or its inactivated molecule (0 or 100 µM), the vulnerability of Ca-PLA₂ activity to carbon monoxide mediated inhibition was assessed. Lastly, the inhibitory response of Ca-PLA₂ activity to exposure to carbon monoxide releasing molecule-2 (0-100 µM) was determined. Ca-PLA₂ activity degraded the velocity of clot growth and clot strength in an activity dependent, exponential manner. Carbon monoxide inhibited Ca-PLA₂ activity in a concentration dependent fashion, with loss of detectable activity at 100 µM of carbon monoxide releasing molecule-2. These findings, while preliminary, open the possibility that other PLA₂ contained in snake venom with multiple toxicities (e.g., myotoxin, neurotoxin) may be heme bearing and CO-inhibitable, which have profound potential basic and clinical science implications.

Agkihpin, a Distinct SVTLE from the Venom of Gloydius halys Pallas: Purification, Characterization and Structure-Activity Determination

Blood clots produced by snake-venom thrombin-like enzymes (SVTLEs) are cleared rapidly, which makes SVTLEs attractive as potential candidates for antithrombotic therapy. We isolated a SVTLE, agkihpin, from the venom of Gloydius halys Pallas. Agkihpin was confirmed to a single-chain TLE with molecular mass of 25.5 kD, pI of 7.43, optimal pH of 8.0 (hydrolyzing TAME), linked carbohydrate absent, and weak fibrinogen clotting activity. It was also found that (i) G. halys might be the latest species in SVTLEs phylogenetic tree; (ii) different level of conservation was shown among the SVTLEs from the Viperidae snakes. Some of those site may account for different activities exhibited by those SVTLEs, especially position 181, at which a fibrinogenolytic activity increase was found when a basic and larger amino acid substituted by a neutral and smaller one; (iii) an extra α-helix constructed with a 'Pro + acidic amino acid + aromatic amino acid' pattern was found in the SVTLEs from Gloydius and Agkistrodon snakes, although it does not necessarily imply an effect on the fibrinogenolytic activity of the SVTLEs. This study provided some new insight into the activity of SVTLE.

Severe Coagulopathy after Ingestion of "Snake Wine"

BACKGROUND

This report describes a patient who developed coagulopathy after ingesting snake wine, which is an alcoholic libation containing an entire venomous snake.

CASE REPORT

A 68-year-old man was admitted to the hospital 19 h after ingesting snake wine. The laboratory features upon admission included unmeasurable activated partial thromboplastin (aPTT) values, prolonged prothrombin time (PT) values, increased fibrinogen levels, modestly elevated fibrin degradation product and D-dimer values, uncorrected aPTT and PT values after a mixing test, and normal levels of aspartate transaminase and alanine transaminase. No pesticides, warfarin, or superwarfarin in the patient's blood or urine were detected. His coagulation profile normalized on the 6(th) day after admission after antivenom treatment. He was discharged 10 days later without sequelae. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The physician should be aware that ingesting snake wine may lead to systemic envenomation. As for coagulopathy, which may develop by ingesting snake venom, related laboratory findings may differ from the features observed after direct envenomation by snakebite.