The effects of a chactoid scorpion venom and its purified toxins on rat blood pressure and mast cells histamine release

Discovering Venom-Derived Drug Candidates Using Differential Gene Expression

Venoms are a diverse and complex group of natural toxins that have been adapted to treat many types of human disease, but rigorous computational approaches for discovering new therapeutic activities are scarce. We have designed and validated a new platform-named VenomSeq-to systematically identify putative associations between venoms and drugs/diseases via high-throughput transcriptomics and perturbational differential gene expression analysis. In this study, we describe the architecture of VenomSeq and its evaluation using the crude venoms from 25 diverse animal species and 9 purified teretoxin peptides. By integrating comparisons to public repositories of differential expression, associations between regulatory networks and disease, and existing knowledge of venom activity, we provide a number of new therapeutic hypotheses linking venoms to human diseases supported by multiple layers of preliminary evidence.

In vitro antischistosomal activity of venom from the Egyptian snake Cerastes cerastes

INTRODUCTION:

We studied the potential in vitro antischistosomal activity of Cerastes cerastes venom on adult Schistosoma mansoni worms.

METHODS:

Live specimens of the horned viper snake, C. cerastes were collected from the Aswan Governorate (Egypt). Venom was collected from snakes by manual milking. Worms of S. mansoni were obtained from infected hamsters by perfusion and isolated from blood using phosphate buffer. Mortality rates of worms were monitored after 3 days of exposure to snake venom at LC50 and various sublethal concentrations (10, 5, 2.5µg/ml). Scanning electron microscopy was used to investigate tegumental changes in treated worms after exposure to LC50 doses of venom.

RESULTS:

The LC50 of C. cerastes venom was 21.5µg/ml. The effect of C. cerastes venom on Schistosoma worms varied according to their sex. The mortality rate of male and female worms after 48-h exposure was 83.3% and 50%, respectively. LC50 of C. cerastes venom induced mild to severe tegumental damage in Schistosoma worms in the form of destruction of the oral sucker, shrinkage and erosion of the tegument, and loss of some tubercle spines.

CONCLUSIONS:

The present study demonstrated that C. cerastes venom exerts potential in vitro antischistosomal activity in a time and dose-dependent manner. These results may warrant further investigations to develop novel schistosomicidal agents from C. cerastes snake venom.

Role of some vasoactive mediators in scorpion envenomed children: Possible relation to envenoming outcome

Scorpion envenomation causes an autonomic storm resulting in changes in the vasoactive mediators' levels which lead to myocardial damage, cardiovascular disturbances, peripheral circulatory failure, pulmonary edema, multi-system-organ-failure and death. The study aimed to determine the circulating levels of adrenaline, noradrenaline, angiotensin converting enzyme (ACE), Angiotensin II (Ang II), kallikrein enzyme, nitric oxide (NO), aldosterone, and electrolytes Na⁺, K⁺ and Ca⁺² in scorpion envenomed children and to evaluate the potential relation between these vasoactive mediators, the severity of scorpion envenoming and the clinical outcome of envenomed children. Forty envenomed children (22 mild and 18 severe cases) along with 10 healthy control children were enrolled in the study. The circulating levels of adrenaline, noradrenaline, Ang II, ACE, kallikrein enzyme, and NO were determined by ELISA, and spectrophotometric assays on admission and 24 h later. On admission, serum aldosterone, and electrolytes; Na⁺, K⁺ and Ca⁺² were determined by RIA, Flame photometer and Flame atomic absorption respectively. All envenomed children showed significant surge of adrenaline, noradrenaline, ACE, Ang II, aldosterone, NO and Na⁺, that concomitantly faced by significant reduction in kallikrein, K⁺ and Ca⁺² on admission. Twenty four hours later, all envenomed children continued to show significant elevation of ACE, Ang II and NO. The severely envenomed children showed considerable reduction in circulating levels of adrenaline, noradrenaline, ACE and Ang II, while dramatic increase in kallikrein activity was reported in comparison to mildly envenomed children after 24 h of medical care. Also, NO exhibited considerable accumulation in non survivors, on admission, that was persistent for the subsequent 24 h and was accompanied by high kallikrein, low catecholamines and Ang II levels compared to survivors. Finally, the hypertensive cases showed substantial higher levels of catecholamine, ACE and Ang II, 24 h after admission. These findings indicated that, disturbances of the studied vasoactive mediators were common in scorpion envenomed children and may account for several inflammatory manifestations and clinical outcome. ACE inhibitors could be considered as possible therapeutic agent in victims with prominent increase in ACE and Ang II while kallikrein inhibitor and antioxidants may be effective in the treatment of late hypotensive ones.