Biochemical and biological characterization of the venoms of Naja kaouthia and Naja mandalayensis from Myanmar and neutralization effects of BPI cobra antivenom

Snakebite is a neglected public health issue, with many scientific and medical issues to be solved. Cobras are among the most common venomous snakes in Myanmar and are responsible for a considerable number of severe snakebite envenoming. There are three species of cobra (Naja kaouthia, Naja mandalayensis and Ophiophagus hannah) in Myanmar. The study aims to characterize the N. kaouthia and N. mandalayensis venoms and to investigate the efficacy of anti-cobra antivenom (BPI) against the two venoms. Protein components and fibrinogenolytic activity were determined by SDS-PAGE. Enzymatic activities for PLA2, protease and acetylcholinesterase were determined by spectrophotometric method. Anticoagulant activity was determined by recalcification time of citrated human plasma. Myotoxicity, necrotizing activity, median lethal dose (LD50) and median effective dose (ED50) were determined by WHO recommended methods. The SDS-PAGE displayed the proteins and enzymes containing in two venoms were different. N. kaouthia venom exhibited more in PLA2, acetylcholinesterase, anticoagulant, fibrinogenolytic and necrotizing activities than N. mandalayensis venom. N. mandalayensis venom had more protease activity and myotoxicity than N. kaouthia venom. The median lethal dose (LD50) of N. kaouthia and N. mandalayensis venom was 4.33 μg/mouse and 5.04 μg/mouse respectively. Both venoms induced fibrinogen Aα chain degradation in 30 min (N. kaouthia) and in 6 h (N. mandalayensis). The same median effective dose (ED50) (19.56 μg/mouse) showed that anti-NK antivenom can neutralize against lethal effect of N. mandalayensis venom. It can also neutralize the protease activity, anticoagulant activity and fibrinogenolytic activity of both venoms. Immunodiffusion and immunoblotting studies showed that the antivenom recognized its homologous venom (N. kaouthia) and cross-reacted against the heterologous venom (N. mandalayensis). The anti-NK antivenom is suitable to use for N. mandalayensis bite if monospecific antivenom is not available.

A Case of Cobra Bite Complicated with Basilar Artery Occlusion

Snakebite is one of the most common complaints related to wilderness medicine. Venomous snakebite manifestation is divided into local and systemic envenomation. For the Elapidae group, the most feared complication is respiratory muscle paralysis due to neurotransmitter malfunction at the neuromuscular junction level which leads to respiratory insufficiency. However, there is a lack of evidence or case report incidence to suggest that it can potentially associate with the development of stroke disorder. We present a rare case of massive posterior circulation infarct in a middle-aged gentleman following a cobra bite. He was brought to our center few hours later following the bite and antivenom was administered. He improved shortly after receiving it. However, he had an abrupt drop in his conscious level several hours later. Noncontrast-enhanced computed tomography (NCCT) brain was performed immediately, but stroke disorder was excluded prematurely. Repeated NCCT imaging which was done 12 h apart showed massive posterior circulation infarction with hydrocephalus. He succumbed to death 3 days later. Given its rarity, the evolution of his clinical condition warrants clinician's early suspicion of potential stroke-related complications that can occur following a cobra bite.

miRNAs derived from cobra venom exosomes contribute to the cobra envenomation

Currently, there is an increasing amount of evidence indicating that exosomes and the miRNAs they contain are crucial players in various biological processes. However, the role of exosomes and miRNAs in snake venom during the envenomation process remains largely unknown. In this study, fresh venom from Naja atra of different ages (2-month-old, 1-year-old, and 5-year-old) was collected, and exosomes were isolated through ultracentrifugation. The study found that exosomes with inactivated proteins and enzymes can still cause symptoms similar to cobra envenomation, indicating that substances other than proteins and enzymes in exosomes may also play an essential role in cobra envenomation. Furthermore, the expression profiles of isolated exosome miRNAs were analyzed. The study showed that a large number of miRNAs were co-expressed and abundant in cobra venom exosomes (CV-exosomes) of different ages, including miR-2904, which had high expression abundance and specific sequences. The specific miR-2094 derived from CV-exosomes (CV-exo-miR-2904) was overexpressed both in vitro and in vivo. As a result, CV-exo-miR-2904 induced symptoms similar to cobra envenomation in mice and caused liver damage, demonstrating that it plays a crucial role in cobra envenomation. These results reveal that CV-exosomes and the miRNAs they contain play a significant regulatory role in cobra envenomation. Our findings provide new insights for the treatment of cobra bites and the development of snake venom-based medicines.

Egyptian cobra (Naja haje haje) venom phospholipase A2: a promising antiviral agent with potent virucidal activity against simian rotavirus and bovine coronavirus

Viral infections are linked to a variety of human diseases. Despite the achievements made in drug and vaccine development, several viruses still lack preventive vaccines and efficient antiviral compounds. Thus, developing novel antiviral agents is of great concern, particularly the natural products that are promising candidates for such discoveries. In this study, we have purified an approximately 15 kDa basic phospholipase A2 (PLA2) enzyme from the Egyptian cobra Naja haje haje venom. The purified N. haje PLA2 showed a specific activity of 22 units/mg protein against 6 units/mg protein for the whole crude venom with 3.67-fold purification. The antiviral activity of purified N. haje PLA2 has been investigated in vitro against bovine coronavirus (BCoV) and simian rotavirus (RV SA-11). Our results showed that the CC50 of PLA2 were 33.6 and 29 µg/ml against MDBK and MA104 cell lines, respectively. Antiviral analysis of N. haje PLA2 showed an inhibition of BCoV and RV SA-11 infections with a therapeutic index equal to 33.6 and 16, respectively. Moreover, N. haje PLA2 decreased the BCoV and RV SA-11 titers by 4.25 log10 TCID50 and 2.5 log10 TCID50, respectively. Thus, this research suggests the potential antiviral activity of purified N. haje PLA2 against BCoV and RV SA-11 infections in vitro.

Validation of the COBRA nomogram for the prediction of cancer specific survival in patients treated with radical cystectomy for bladder cancer: An international wide cohort study

BACKGROUND

Recently, the Cancer of the Bladder Risk Assessment (COBRA) score has been introduced to estimate cancer specific survival (CSS) after radical cystectomy for bladder cancer.

OBJECTIVES

Aim of our study was to validate the COBRA score, assessing the effect of age, tumor stage and lymph-nodes status on CSS after cystectomy in patients with bladder cancer.

DESIGN, SETTING, AND PARTICIPANTS

A consecutive series of 2395 patients with primitive or recurrent bladder cancer treated with radical cystectomy in 4 centers were evaluated.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The role of COBRA score as predictor of CSS was assessed using the Kaplan Meier and Cox proportional hazards analyses. Accuracy of COBRA score was evaluated by Harrell's C test.

RESULTS AND LIMITATIONS

Median age was 66 (IQR 58/73) years. Overall, at a median follow-up of 48 (IQR 22/92) months, 642 patients (27%) died of bladder cancer. On Cox proportional hazards analyses, COBRA score was a significant predictor of CSS (HR 1.54, 95%CI 1.47-1.61) (Table 1). The predictive accuracy of the COBRA score was 0.71. A sub analysis including pooled COBRA score (0 vs 1-3 vs 4 vs 5-7) improved the clinical applicability with the same accuracy.

CONCLUSION

In our experience, the COBRA score is an excellent tool to predict cancer specific survival. The COBRA Score represents a practical and easy tool that may help urologists to classify the CSS of patients treated with radical cystectomy, to predict the oncological outcome and finally to counsel bladder cancer patients.

Unexpected lack of specialisation in the flow properties of spitting cobra venom

Venom spitting is a defence mechanism based on airborne venom delivery used by a number of different African and Asian elapid snake species ('spitting cobras'; Naja spp. and Hemachatus spp.). Adaptations underpinning venom spitting have been studied extensively at both behavioural and morphological level in cobras, but the role of the physical properties of venom itself in its effective projection remains largely unstudied. We hereby provide the first comparative study of the physical properties of venom in spitting and non-spitting cobras. We measured the viscosity, protein concentration and pH of the venom of 13 cobra species of the genus Naja from Africa and Asia, alongside the spitting elapid Hemachatus haemachatus and the non-spitting viper Bitis arietans By using published microCT scans, we calculated the pressure required to eject venom through the fangs of a spitting and a non-spitting cobra. Despite the differences in the modes of venom delivery, we found no significant differences between spitters and non-spitters in the rheological and physical properties of the studied venoms. Furthermore, all analysed venoms showed a Newtonian flow behaviour, in contrast to previous reports. Although our results imply that the evolution of venom spitting did not significantly affect venom viscosity, our models of fang pressure suggests that the pressure requirements to eject venom are lower in spitting cobras than in non-spitting cobras.

Illegal online pet trade in venomous snakes and the occurrence of snakebites in Brazil

Greater access to the Internet has boosted the online pet trade and especially enabled the trade in niche-targeted groups, such as venomous species. Despite their fearsome reputation, an array of venomous animals, such as snakes, spiders and scorpions arise interest among pet hobbyists, which exposes owners, sellers, and others involved in their transport and maintenance to potentially serious accidents by envenomation. To assess the potential risk to human health posed by the trade and ownership of venomous pet snakes, we examined social media posts trading or portraying native and exotic venomous species as pets (Facebook™ and YouTube™) and official seizures in Brazil between 2015 and 2020. In addition, we recorded all venomous snakebite events occurring in the country during the same period from the Brazilian Ministry of Health database. We compiled 114,931 venomous snakebite events resulting in over 600 human deaths. Bothrops spp. and Crotalus spp. were responsible for 86% and 10% of these events. We recorded 241 individual venomous snakes kept as pets of at least 16 species (seven native and nine non-native). The taxa with higher numbers of snakebites were also those most often kept as pets. Venomous pet snakes were sold at low prices, US$ 71.70 ± 18.44 on average. Our findings highlight a dangerous market, given the similarity of taxa raised as pets and those causing snakebites, combined with low availability of anti-venom for exotic species in Brazil. Additionally, several of the venomous pet snakes recorded are invasive species in many countries. Trade in venomous snakes is prohibited in Brazil, but the law is not well-enforced. To curb this illegal market and discourage consumer demand, we suggest that tougher penalties for sellers and owners should be considered, along with the development of awareness campaigns on the consequences of the snakebite injuries and the lack of antivenoms.

Using body mass index ignores the intensive training of elite special force personnel

Body mass index is a common and well-known measure in daily life. A body mass index higher than 25 is assumed to be an indicator for overweight and obesity and a high amount of total body fat. But body mass index overestimates body fat in subjects with high muscle mass and underestimates it in persons with a low lean body mass, especially in elderly and diseased persons. In the present study, we investigate the performance of the body mass index as a measure of body fatness and its ability to distinguish between well-trained and untrained subjects. Twenty-one well-trained male members of a police task force named “Cobra” and 38 non-active controls, matched by age, weight and height were participants of the study. The age range of these subjects was between 30 and 45 years. Subcutaneous adipose tissue thicknesses and body fat distributions were measured non-invasively by an optical device named the “Lipometer.” Statistics were performed with SPSS. We found that the body mass index did not show a difference between the two groups, whereas all Lipometer results were able to discriminate significantly between the trained and untrained subjects. Furthermore, the receiver operating characteristic curve analysis was calculated and all Lipometer measurements provided significant results up to a correct classification of all subjects of 86.4%, which was for the lateral thigh body site. In conclusion, the body mass index was not able to recognize the difference between trained and untrained participants, while body fat distribution measured with the Lipometer was able to distinguish more clearly the large body fat differences between these two groups.

Impact statement

Body mass index (BMI) is a common measure of body fatness but overestimates body fat in subjects with high muscle mass. We have developed previously a device named “Lipometer,” an alternative way to measure body fatness. We show herein that the Lipometer is able to distinguish more clearly (than the BMI) the large body fat differences between well-trained and untrained subjects. Thus, the Lipometer is superior to BMI with respect to body fat measurements.

Incidence of snakebites in 3 different geographic regions in Thua Thien Hue province, central Vietnam: Green pit vipers and cobras cause the majority of bites

BACKGROUND

The annual incidence of snakebites in Vietnam is not known and only few publications about snakebite envenoming and medically relevant snakes can be found in English language literature. The present community-based surveys provide data on incidence of snakebites in three different geographic regions of Thua Thien Hue (TT Hue) province, central Vietnam and snake species responsible for bites in this region.

METHODOLOGY/RESULTS

The cross-sectional community based surveys were conducted from March to July 2017. Multistage cluster sampling was applied and snakebite incidence was calculated at 58 snakebites per 100,000 person-years for the entire province, and 172, 69 and 10 snakebites per 100,000 person-years in the mountainous, coastal and urban region of TT Hue province, respectively. Thirty-one snakebite victims interviewed during the surveys reported 18 (58%) green pit viper bites (Trimeresurus species), 5 (16%) cobra bites (Naja kaouthia, Naja siamensis), 2 (7%) krait bites (Bungarus candidus, Bungarus fasciatus), 2 (7%) red-necked keelback bites (Rhabdophis subminiatus) and 4 bites from unidentified snakes (13%). The outcome was favourable for 28 snakebite victims (90%), two (6%) had minor sequelae and one (3%) victim died after a Malayan krait bite. Two hundred and twenty-one snakebite patients were treated in 9 district hospitals and one central hospital in TT Hue between 2014 and 2016. Eighty green pit vipers (84%), 12 cobras (13%) and 3 kraits (3%) were responsible for bites in 95 patients where snake identification was documented.

CONCLUSIONS

Incidence of snakebites is surprisingly low in TT Hue province in central Vietnam in comparison to other regions in Asia, particularly to neighbouring Lao PDR. However, snakebites are still a significant health problem in the mountainous region and green pit vipers and cobras cause the vast majority of bites.

Whole snake venoms: Cytotoxic, anti-metastatic and antiangiogenic properties

Currently, biological and organic substances are screened in order to find a new generation of therapeutics active against cancer. Previous research has identified promising candidate peptides in snake venom. In this study, venoms from different snake species (Naja annulifera, Naja kaouthia, Ophiophagus hannah and Echis carinatus) were screened for potential anti-cancer properties using pancreatic tumour cells as the assay system. The cells were incubated with venom and then subjected to the following analyses: (i) in vitro cell death (ii) in vitro migration (iii) in vivo dissemination and (iv) in vivo angiogenesis. For the in vivo assays, the cells, after incubation and labelling, were transplanted into the yolk sac of zebrafish embryos for motility and angiogenesis. The results showed strong effects in cells treated with venoms from Ophiophagus hannah and Echis carinatus in the in vitro assays. In the in vivo assays, venom derived from Ophiophagus hannah had the most potent effects with respect to angiogenesis. These venoms might therefore be considered as candidates for further studies.

Carbon monoxide inhibits hemotoxic activity of Elapidae venoms: potential role of heme

Envenomation by hemotoxic enzymes continues to be a major cause of morbidity and mortality throughout the world. With regard to treatment, the gold standard to abrogate coagulopathy caused by these venoms is still the administration of antivenom; however, despite antivenom therapy, coagulopathy still occurs and recurs. Of interest, this laboratory has demonstrated in vitro and in vivo that coagulopathy inducing venom derived from snakes of the family Viperidae exposed to carbon monoxide (CO) is inhibited, potentially by an attached heme. The present investigation sought to determine if venoms derived from snakes of the Elapidae family (taipans and cobras) could also be inhibited with CO or with the metheme inducing agent, O-phenylhydroxylamine (PHA). Assessing changes in coagulation kinetics of human plasma with thrombelastography, venoms from Elapidae snakes were exposed in isolation to CO (five species) or PHA (one specie) and placed in human plasma to assess changes in procoagulant or anticoagulant activity. The procoagulant activity of two taipan venoms and anticoagulant activity of three cobra venoms were significantly inhibited by CO. The venom of the inland taipan was also inhibited by PHA. In sum, these data demonstrate indirectly that the biometal heme is likely bound to these disparate venoms as an intermediary modulatory molecule. In conclusion, CO may not just be a potential therapeutic agent to treat envenomation but also may be a potential modulator of heme as a protective mechanism for venomous snakes against injury from their own proteolytic venoms.

Comparison of the primary structures, cytotoxicities, and affinities to phospholipids of five kinds of cytotoxins from the venom of Indian cobra, Naja naja

The molecular mechanism underlying the hemolytic and cytolytic processes of cobra cytotoxins (CTXs) is not yet fully elucidated. To examine this, we analyzed the amino acid sequences, hemolytic and cytotoxic activities, and affinities to phospholipids of the five major CTXs purified from the venom of Indian cobra, Naja naja. CTX2, CTX7, and CTX8 belonged to S-type, and CTX9 and CTX10 to P-type. Comparisons of CTX7 with CTX8 and CTX9 with CTX10 revealed similar primary structures and hemolytic and cytolytic activities. CTX2, whose primary structure was rather different from the others, showed several times weaker hemolytic and cytolytic biological activities than the others. The comparison of CTX2 with CTX7 suggested the importance of Lys30 in loop II for the strong hemolytic and cytolytic activities of S-type CTXs. Cloning of 12 CTX cDNAs from the Naja naja venom cDNA library revealed that 18 out of 23 substitutions found in CTX cDNAs were nonsynonymous. This clearly indicated the accelerated evolution of CTX genes. Multiple sequence alignment of 51 kinds of CTX cDNAs and calculations of nonsynonymous and synonymous substitutions indicated that the codons coding the three loops' regions, which may interact with the hydrophobic tails of phospholipids, have undergone an accelerated evolution. In contrast, the codons coding for amino acid residues considered to participate in the recognition and binding of the hydrophilic head groups of phospholipids, eight Cys residues, and those likely stabilizing β core structure, were all conserved.

Protective activity of medicinal plants and their isolated compounds against the toxic effects from the venom of Naja (cobra) species

ETHNOPHARMACOLOGICAL RELEVANCE

Various medicinal plants have protective properties against the toxicities of the venom of cobra snake (Naja species). They may be used as local first aid for the treatment of snakebite victims, and can significantly inhibit lethality, cardio-, neuro-, nephro- and myotoxicity, hemorrhage, and respiratory paralysis induced by the cobra snake venom. The plants or their extracts may also complement the benefits of conventional anti-serum treatment.

AIM OF THE REVIEW

This review provides information on the protective, anti-venom, properties of medicinal plants against snakebites from cobras. In addition, it identifies knowledge gaps and suggests further research opportunities.

METHODS

The literature was searched using databases including Google Scholar, PubMed, ScienceDirect, Scopus and Web of Science. The searches were limited to peer-reviewed journals written in English with the exception of some books and a few articles in foreign languages.

RESULTS

The plants possess neutralization properties against different cobra venom enzymes, such as hyaluronidase, acetylcholinesterase, phospholipase A2 and plasma proteases. Different active constituents that show promising activity against the effects of cobra venom include lupeol acetate, β-sitosterol, stigmasterol, rediocides A and G, quercertin, aristolochic acid, and curcumin, as well as the broad chemical groups of tannins, glycoproteins, and flavones. The medicinal plants can increase snakebite victim survival time, decrease the severity of toxic signs, enhance diaphragm muscle contraction, block antibody attachment to venom, and inhibit protein destruction. In particular, the cardiovascular system is protected, with inhibition of blood pressure decline and depressed atrial contractility and rate, and prevention of damage to heart and vessels. The designs of experimental studies that show benefits, or otherwise, of use of medicinal plants have some limitations: deficiency in identification and isolation of active constituents responsible for therapeutic activity; lack of comparison with reference drugs; and little investigation of the mechanism of anti-venom activity.

CONCLUSION

Despite some current deficiencies in experimental or clinical analysis, medicinal plants with anti-venom characteristics are effective and so are candidates for future therapeutic agents. We suggest that emphasis on identification and testing of active ingredients in research in the future will assist better understanding of their anti-venom activity.

Neutralization of cobra venom by cocktail antiserum against venom proteins of cobra (Naja naja naja)

Naja naja venom was characterized by its immunochemical properties and electrophoretic pattern which revealed eight protein bands (14 kDa, 24 kDa, 29 kDa, 45 kDa, 48 kDa, 65 kDa, 72 kDa and 99 kDa) by SDS-PAGE in reducing condition after staining with Coomassie Brilliant Blue. The results showed that Naja venom presented high lethal activity. Whole venom antiserum or individual venom protein antiserum (14 kDa, 29 kDa, 65 kDa, 72 kDa and 99 kDa) of venom could recognize N. naja venom by Western blotting and ELISA, and N. naja venom presented antibody titer when assayed by ELISA. The neutralization tests showed that the polyvalent antiserum neutralized lethal activities by both in vivo and in vitro studies using mice and Vero cells. The antiserum could neutralize the lethal activities in in-vivo and antivenom administered after injection of cobra venom through intraperitoneal route in mice. The cocktail antiserum also could neutralize the cytotoxic activities in Vero cell line by MTT and Neutral red assays. The results of the present study suggest that cocktail antiserum neutralizes the lethal activities in both in vitro and in vivo models using the antiserum against cobra venom and its individual venom proteins serum produced in rabbits.