Elsevier

Thrombosis Research

Volume 125, Issue 4, April 2010, Pages e149-e152
Thrombosis Research

Regular Article
The effect of different snake venoms and anti-venoms on thrombin clotting time in human plasma

https://doi.org/10.1016/j.thromres.2009.10.020Get rights and content

Abstract

Background

Crotaline snake species, or pit vipers, are distributed throughout Asia and America. While much is known about the clinical effect of these snake venoms, there is a lack of evidence related to the various anti-venoms available and their effectiveness in reversing the effect of different venoms.

Aim

This study aimed to determine the interaction of the venoms of the following species: Crotalus unicolor, Crotalus adamanteus, Crotalus vegrandis, Trimeresurus spp, Calloselasma rhodostoma, Bothriechis schlegelii and Agkistrodon and the following anti-venoms: Anticrotalico, Antivipmyn, Antibotropico, Antifidico and SAIMR by evaluating their effect on the thrombin clotting time in human plasma.

Method

The interactions of venoms and anti-venoms were evaluated using thrombin clotting time in human plasma.

Results

The results demonstrate that Anticrotalico anti-venom was most effective for the Crotalid species (Crotalus unicolor, Crotalus adamanteus, Crotalus vegrandis).

Anticrotalico extended the time to clot formation 2.7 fold for Crotalus Unicolor, 3 fold for Crotalus Adamanteus and 4.6 fold for Crotalus Vegrandis. The anti-venoms most efficient in reversing the effect of the Trimeresurus spp venom, were Anticrotalico, Antivipmyn, Antibotropico and Antifidico anti-venoms, which all completely reversed the effect of clot formation as evident by no clot formation within the 999 seconds measurement limit. Bothriechis schlegelii venom was neutralized by all anti-venoms tested. Calloselasma rhodostoma venom was neutralized by Antifidico as well as Anticrotalico. The most efficient anti-venoms against the Agkistrodon venom were Anticrotalico and Antibotropico.

In general, monovalent anti-venoms had improved efficiency for their corresponding snake species, depending highly on the composition of the snake venom.

This study confirms the importance of considering the choice of anti-venom in a clinical setting, to reverse the effect of specific snake venoms. In addition, this study suggests that some anti-venoms can be considered for use against a variety of snake-venoms.

Introduction

Snake venoms can be deadly and the only specific treatment is available through the use of anti-venoms. Therefore, understanding of the specificity of particular anti-venoms against particular snake venoms is crucial.

Previous studies have investigated the feeding behaviour, reportable events of envenomation, haematological effects, including the purification and characterization of haemorrhagic fraction of members of the crotalid snake species including Crotalus unicolor, Crotalus atrox, Crotalus adamanteus[1], [2], [3], [4]. Further investigations on the venoms of the crotalus species, including Crotalus adamanteus and Crotalus atrox, were performed, focusing on the haemorrhagic dose required to determine the LD50 using mice rodents. Anti-venoms including Anticoral were used to reverse the haemorrhagic effects of the venoms from the Crotalus species of snakes [5].

In addition, the Cortaid and Viperid species was investigated on their pro-coagulant properties, including a comparison study of the biochemical and physicochemical properties and interference in platelet functions [6] and a study on the effects of snake venoms on hemostasis [7]. The effect of snake venom pro-coagulants on snake plasma was also characterized in 2002 [8].

The effectiveness of Antivipmyn anti-venom was previously characterized in 2008 against African vipers and elapids [9] and its efficacy against two anti-venoms from North American snakes was investigated in a study in 2003 [10]. The Antivipmyn anti-venom was not previously tested against any of the venoms used in this study and has to date not been directly tested in human plasma.

A study performed in 2001 focused on Phospholipase A2 enzymes in snake venoms. Phospholipase A2 (PLA2), are enzymes which target specific tissues and organs and thereby exert their pharmacology activity according to their catalytic activity, was investigated in this study too. PLA2 enzymes are able to degrade coagulant phospholipids and therefore having an anti-coagulant activity [11].

The difference in efficiency between monovalent (Anticrotalico, Antivipmy, Antibotropico) and polyvalent (Antifidico, SAIMR) anti-venoms for treating envenomation by Crotalid (Crotalus unicolor, Crotalus adamanteus, Crotalus vegrandis) and Viperid (Calloselasma rhodostoma, Agkistrodon, Bothriechis schlegelii and Trimeresurus spp) snake venoms has not been investigated to date. This study aimed to determine the differences in the interaction of these venoms and anti-venoms by evaluating their effect on the thrombin clotting time in human plasma.

Section snippets

Venoms:

The following groups of Crotalid and Viperid snake venoms were used in the present study. The venoms which belong to the Crotalid snake family include Crotalus unicolor (Aruba island rattlesnake); Crotalus adamanteus (Eastern diamondback rattlesnake); Crotalus vegrandis (Uracoan rattlesnake). The venoms which belong to the Viperid snake family include the following venoms: Trimeresurus spp (Green pitviper); Calloselasma rhodostoma (Malayan pitviper), Bothriechis schlegeli (Eyelash viper) and

Results

In this study, five anti-venoms were used to determine their specificity and effectiveness in neutralizing the pro-coagulant effect of seven different snake-venoms in human plasma. All venoms differ in their pro-coagulant effects and the different anti-venoms therefore vary in their efficiency in neutralizing the venoms. All results were compared with a reference value, which was determined for every venom tested. Therefore venom was added to plasma until a clot was formed.

Table 1 demonstrates

Discussion

This study investigated the assumption monovalent anti-venoms are specific and effective for the venom, for which they were originally prepared. On the other hand, polyvalent anti-venoms should be effective at neutralizing the effects of every venom species they were made for, not only one species but for the family/genus, therefore, not being as specific in effect as monovalent anti-venoms.

This study demonstrates that Anticrotalico anti-venom was most effective at neutralizing the coagulant

Conflict of interest

The authors declare that there are no conflicts of interest.

Acknowledgements

The authors acknowledge Dr. Ken D. Winkel, as the head of the Australian Venom Research Unit for supplying the anti-venoms and Venom Supplies and Monash University for supplying the venoms used in this study.

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