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1.
J Avian Med Surg ; 36(1): 63-69, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35526166

RESUMO

Envenomation in avian species can result in death, with few cases of successful treatment described. A juvenile, wild-caught, intact female red-tailed hawk (Buteo jamaicensis) used in falconry was presented for emergency evaluation after being bitten by a Northern Pacific rattlesnake (Crotalus oreganus) approximately 2 hours before presentation. On presentation, the bird was quiet, alert, and responsive, with moderate swelling and discomfort of the digits on the right foot. Complete blood count (CBC) and plasma biochemistry abnormalities included a regenerative left shift, severe lymphopenia, and a moderate hypoproteinemia characterized by moderate hypoalbuminemia. Analgesic and antibiotic medications were administered during hospitalization. In addition, 5 mL of VenomVet was administered intravenously with crystalloid fluids over 60 minutes; no adverse effects were noted secondary to infusion. Improvement in the swelling was observed immediately after antivenom administration and nearly resolved within 12 hours. Complete resolution of digital swelling with no discomfort on palpation of that foot was observed 1 week after initial presentation. Blood collected at the 1 week reexamination was submitted for a CBC and plasma biochemistry panel. The results of the CBC revealed a reduced regenerative left shift, increased heterophil count, and a moderate monocytosis; the lymphopenia was resolved. A mild hypoalbuminemia still persisted. Ten months after presentation, the bird was reported to be doing well with no changes in function of the right foot and subsequently released from captivity.


Assuntos
Doenças das Aves , Crotalinae , Falcões , Hipoalbuminemia , Linfopenia , Mordeduras de Serpentes , Animais , Antivenenos/uso terapêutico , Doenças das Aves/tratamento farmacológico , Feminino , Hipoalbuminemia/tratamento farmacológico , Hipoalbuminemia/veterinária , Linfopenia/tratamento farmacológico , Linfopenia/veterinária , Mordeduras de Serpentes/tratamento farmacológico , Mordeduras de Serpentes/veterinária
2.
Toxins (Basel) ; 14(4)2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35448838

RESUMO

Snake envenoming causes rapid systemic and local effects that often result in fatal or long-term disability outcomes. It seems likely that acute phase and inflammatory responses contribute to these haemorrhagic, coagulopathic, neurotoxic, nephrotoxic and local tissue destructive pathologies. However, the contributory role of acute phase/inflammatory responses to envenoming is under-researched and poorly understood-particularly for envenoming by sub-Saharan African venomous snakes. To provide data to help guide future studies of human patients, and to explore the rationale for adjunct anti-inflammatory medication, here we used an in vivo murine model to systematically assess acute phase and inflammatory responses of mice to ten African snake venoms. In addition to investigating snake species-specific effects of venom on the cardiovascular system and other key organs and tissues, we examined the response to intravascular envenoming by acute phase reactants, including serum amyloid A, P-selectin and haptoglobin, and several cytokines. Venoms of the spitting (Naja nigricollis) and forest (N. melanoleuca) cobras resulted in higher acute phase and inflammatory responses than venoms from the other cobras, mambas and vipers tested. Naja nigricollis venom also stimulated a 100-fold increase in systemic interleukin 6. Thin blood films from venom-treated mice revealed species-specific changes in red blood cell morphology, indicative of membrane abnormalities and functional damage, lymphopenia and neutrophil leukocytosis. Our ex vivo assays with healthy human blood treated with these venoms identified that N. nigricollis venom induced marked levels of haemolysis and platelet aggregation. We conclude that African snake venoms stimulate very diverse responses in this mouse model of acute systemic envenoming, and that venoms of the African cobras N. nigricollis and N. melanoleuca, in particular, cause marked inflammatory and non-specific acute phase responses. We also report that several African snake venoms cause haemolytic changes. These findings emphasise the importance of understanding acute responses to envenoming, and that further research in this area may facilitate new diagnostic and treatment approaches, which in turn may lead to better clinical outcomes for snakebite patients.


Assuntos
Mordeduras de Serpentes , Animais , Antivenenos/farmacologia , Antivenenos/uso terapêutico , Venenos Elapídicos/uso terapêutico , Elapidae , Hemólise , Humanos , Camundongos , Mordeduras de Serpentes/tratamento farmacológico , Venenos de Serpentes/uso terapêutico
3.
Toxins (Basel) ; 14(4)2022 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-35448844

RESUMO

In Colombia, on average 2.9% of the nearly 5600 snakebite events that occur annually involve the rattlesnake Crotalus durissus cumanensis. The envenomation by this snake is mainly characterized by neurotoxicity and the main toxin is crotoxin (~64.7% of the total venom). The Instituto Nacional de Salud (INS) produces a polyvalent antivenom aimed at the treatment of bothropic, crotalid, and lachesic envenomations; nonetheless, its immune reactivity profile and neutralizing capacity over biological activities of the C. d. cumanensis venom has been poorly evaluated. In this sense, the study aims: (1) to describe an in-depth exploration of its immunoreactivity through second-generation antivenomics and HPLC fraction-specific ELISA immunoprofiles; and (2) to evaluate the neutralization pattern of the rattlesnake venom in vitro and in vivo biological activities. The results obtained showed a variable recognition of crotoxin subunits, in addition to a molecular mass-dependent immunoreactivity pattern in which the disintegrins were not recognized, and snake venom metalloproteinases and L-amino acid oxidases were the most recognized. Additionally, a high neutralization of proteolytic and coagulant activities was observed, but not over the PLA2 activity. Further, the median effective dose against C. d. cumanensis venom lethality was 962 µL of antivenom per mg of venom. In conclusion, (1) the antivenom recognition over the crotoxin and the disintegrins of the C. d. cumanensis should be improved, thus aiming upcoming efforts for the exploration of new techniques and approaches in antivenom production in Colombia, and (2) the neutralization activity of the antivenom seems to follow the molecular mass-dependent recognition pattern, although other explanations should be explored.


Assuntos
Venenos de Crotalídeos , Crotoxina , Animais , Antivenenos , Colômbia , Venenos de Crotalídeos/toxicidade , Crotalus , Desintegrinas
4.
Toxins (Basel) ; 14(4)2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35448862

RESUMO

Sea snake venom is extremely toxic, and it can induce severe respiratory failure and cause high mortality. The most effective first aid treatment for sea snake bites is to inject antivenom as soon as possible. However, in China, there are only four types of terrestrial snake antivenoms, none of which are effective in the treatment of sea snake bites. In order to develop an antivenom for the dominant species of sea snakes in Chinese seas, Hydrophis curtus venom (HcuV) was chosen as the antigen to immunize horses. From immune plasma, a high-titer Hydrophis curtus antivenom (HcuAV) was prepared. In vitro assessment showed that HcuAV had a cross-neutralizing capacity against HcuV and Hydrophis cyanocinctus venom (HcyV). In vivo assessment indicated that HcuAV injection could significantly improve the survival rates of the HcuV and HcyV envenomated mice (0% to 100% and 87.5%, respectively) when it was injected at a sufficient amount within the shortest possible time. In addition, HcuAV could also effectively alleviate multiple organ injuries caused by HcuV. These results provide experimental support for the future clinical application of HcuAV.


Assuntos
Hydrophiidae , Mordeduras de Serpentes , Animais , Antivenenos/farmacologia , Venenos Elapídicos/toxicidade , Cavalos , Soros Imunes , Camundongos , Mordeduras de Serpentes/tratamento farmacológico
5.
Toxins (Basel) ; 14(4)2022 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-35448869

RESUMO

Russell's viper (Daboia russelii), one of the 'Big Four' venomous snakes in India, is responsible for the majority of snakebite-induced deaths and permanent disabilities. Russell's viper bites are known to induce bleeding/clotting abnormalities, as well as myotoxic, nephrotoxic, cytotoxic and neurotoxic envenomation effects. In addition, they have been reported to induce rare envenomation effects such as priapism, sialolithiasis and splenic rupture. However, Russell's viper bite-induced pseudoaneurysm (PA) has not been previously reported. PA or false aneurysm is a rare phenomenon that occurs in arteries following traumatic injuries including some animal bites, and it can become a life-threatening condition if not treated promptly. Here, we document two clinical cases of Russell's viper bites where PA has developed, despite antivenom treatment. Notably, a non-surgical procedure, ultrasound-guided compression (USGC), either alone, or in combination with thrombin was effectively used in both the cases to treat the PA. Following this procedure and additional measures, the patients made complete recoveries without the recurrence of PA which were confirmed by subsequent examination and ultrasound scans. These data demonstrate the development of PA as a rare complication following Russell's viper bites and the effective use of a simple, non-surgical procedure, USGC for the successful treatment of PA. These results will create awareness among healthcare professionals on the development of PA and the use of USGC in snakebite victims following bites from Russell's vipers, as well as other viper bites.


Assuntos
Falso Aneurisma , Síndromes Neurotóxicas , Víbora de Russell , Mordeduras de Serpentes , Falso Aneurisma/diagnóstico por imagem , Falso Aneurisma/etiologia , Falso Aneurisma/terapia , Animais , Antivenenos/uso terapêutico , Humanos , Masculino , Síndromes Neurotóxicas/tratamento farmacológico , Mordeduras de Serpentes/complicações , Mordeduras de Serpentes/diagnóstico , Mordeduras de Serpentes/terapia , Ultrassonografia de Intervenção , Venenos de Víboras/uso terapêutico
6.
Toxins (Basel) ; 14(4)2022 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-35448874

RESUMO

In Colombia, the genus Micrurus includes 30 species, of which M. mipartitus and M. dumerilii are the most widely distributed. Micrurus causes less than 3% of the approximately 5000 cases of snakebite per year. The elapid envenomation caused by the snakes from the Micrurus genus, are characterized by the severity of their clinical manifestations, due to the venom neurotoxic components such as three-finger toxins (3FTx) and phospholipases (PLA2). The treatment for snakebites is the administration of specific antivenoms, however, some of them have limitations in their neutralizing ability. A strategy proposed to improve antivenoms is to produce antibodies against the main components of the venom. The aim of this work was to produce an antivenom, using an immunization protocol including the main 3FTx and PLA2 responsible for M. mipartitus lethality. The antibody titers were determined by ELISA in rabbits' serum. The immunized animals elicited a response against toxins and whole venom. The Immunoglobulin G (IgGs) obtained were able to neutralize the lethal effect of their homologous toxins. A combination of antivenom from M. mipartitus with antitoxins improved their neutralizing ability. In the same way, a mixture of anti 3FTx and PLA2 protected the mice from a 1.5 median lethal dose (LD50) of M. mipartitus venom. The results showed that this might be a way to improve antibody titers specificity against the relevant toxins in M. mipartitus venom and indicated that there is a possibility to develop and use recombinant 3FTx and PLA2 toxins as immunogens to produce antivenoms. Additionally, this represents an alternative to reduce the amount of venom used in anti-coral antivenom production.


Assuntos
Cobras Corais , Mordeduras de Serpentes , Toxinas Biológicas , Animais , Antivenenos/farmacologia , Venenos Elapídicos/toxicidade , Elapidae , Camundongos , Neurotoxinas/toxicidade , Fosfolipases A2 , Coelhos
7.
Toxins (Basel) ; 14(4)2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-35448886

RESUMO

Despite antivenoms being the only established specific treatment for neuromuscular paralysis arising from snake envenoming, their ability to reverse the post-synaptic neurotoxicity in snake envenoming is poorly understood. We investigated the ability of five commercial antivenoms i.e., King cobra monovalent, Thai cobra monovalent, Thai neuro polyvalent, Indian polyvalent and Australian polyvalent antivenoms to reverse neurotoxicity induced by the venoms of King cobra (Ophiophagus hannah, 3 µg/mL), Indian cobra (Naja naja, 5 µg/mL) and Thai cobra (Naja kaouthia, 3 µg/mL) using the in vitro chick-biventer cervicis nerve-muscle preparation. All three venoms displayed post-synaptic neurotoxicity, which was prevented by all tested antivenoms (40 µL/mL) added to the bath prior to venom. All antivenoms partially reversed the established post-synaptic neuromuscular block after the addition of the three venoms during a 180 min observation period, but to varying degrees and at different rates. The neurotoxic effects of O. hannah venom recovered to a greater magnitude (based on twitch height restoration) and faster than the neurotoxicity of N. kaouthia venom, which recovered to a lower magnitude more slowly. The recovery of post-synaptic neurotoxicity by N. naja venom was hindered due to the likely presence of cytotoxins in the venom, which cause direct muscle damage. The observations made in this study provide further evidence that the commercial antivenoms are likely to actively reverse established α-neurotoxin-mediated neuromuscular paralysis in snake envenoming, and there is cross-neutralisation with different antivenoms.


Assuntos
Síndromes Neurotóxicas , Mordeduras de Serpentes , Animais , Antivenenos/farmacologia , Austrália , Venenos Elapídicos/toxicidade , Elapidae , Naja , Naja naja , Síndromes Neurotóxicas/etiologia , Paralisia , Mordeduras de Serpentes/tratamento farmacológico , Venenos de Serpentes
8.
Toxins (Basel) ; 14(4)2022 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-35448894

RESUMO

Antivenom immunotherapy is the mainstay of treatment for snakebite envenoming. Most parts of the world affected by snakebite envenoming depend on broad-spectrum polyspecific antivenoms that are known to contain a low content of case-specific efficacious immunoglobulins. Thus, advances in toxin-specific antibodies production hold much promise in future therapeutic strategies of snakebite envenoming. We report anti-3FTxs monoclonal antibodies developed against N. ashei venom in mice. All the three test mAbs (P4G6a, P6D9a, and P6D9b) were found to be IgG antibodies, isotyped as IgG1. SDS-PAGE analysis of the test mAbs showed two major bands at approximately 55 and 29 kDa, suggestive of immunoglobulin heavy and light chain composition, respectively. The immunoaffinity-purified test mAbs demonstrated higher binding efficacy to the target antigen compared to negative control. Similarly, a cocktail of the test mAbs was found to induce a significantly higher inhibition (p-value < 0.0001) compared to two leading commercial brands of antivenoms on the Kenyan market, implying a higher specificity for the target antigen. Both the test mAbs and 3FTxs polyclonal antibodies induced comparable inhibition (p-value = 0.9029). The inhibition induced by the 3FTxs polyclonal antibodies was significantly different from the two antivenoms (p-value < 0.0001). Our results demonstrate the prospects of developing toxin-specific monoclonal-based antivenoms for snakebite immunotherapy.


Assuntos
Antineoplásicos Imunológicos , Mordeduras de Serpentes , Animais , Anticorpos Monoclonais/farmacologia , Antivenenos/uso terapêutico , Venenos Elapídicos , Imunoglobulina G , Quênia , Camundongos , Naja/metabolismo , Mordeduras de Serpentes/tratamento farmacológico
9.
Emerg Med Clin North Am ; 40(2): 313-326, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35461625

RESUMO

This review discusses the distinct envenomation syndromes produced by North American species of snakes and arthropods, specifically the Crotalinae subfamily of snakes, which includes cottonmouths, copperheads, and rattlesnakes; coral snakes; Latrodectus and Loxosceles species of arachnid; and Centruroides sculpturatus, the only species of North American scorpion capable of producing an envenomation syndrome. The authors discuss the epidemiology, pathophysiology, and presentation of these syndromes and emphasize the varying degrees to which these syndromes can manifest clinically. Finally, the management of each envenomation syndrome is addressed. Special attention is paid to available antivenoms, their indications for use, and their side effects.


Assuntos
Artrópodes , Mordeduras de Serpentes , Animais , Antivenenos/uso terapêutico , Humanos , América do Norte , Mordeduras de Serpentes/diagnóstico , Mordeduras de Serpentes/epidemiologia , Mordeduras de Serpentes/terapia , Síndrome
10.
Artigo em Inglês | MEDLINE | ID: mdl-35457571

RESUMO

Snakebite envenoming causes more than 140,000 deaths annually and at least triple this number of disabilities. The World Health Organization classified snakebite as a Neglected Tropical Disease in 2017 and developed a strategy to halve death and disability from snakebite by 2030. To achieve this goal, snakebite victims need to receive safe and effective treatment. This descriptive, cross-sectional study surveyed student health professionals (N = 312) in Dar es Salaam, Tanzania, and was designed to identify major gaps in community practices and hospital resources for snakebite treatment. Participants reported using traditional community practices (44%, 95% confidence interval (CI) = 39-50%), allopathic practices (7%, 95% CI = 5-11%), or a combination of both (49%, 95% CI = 43-54%) to treat snakebite. Harmful practices included tight arterial tourniquets (46%, 95% CI = 41-52%) and wound incisions (15%, 95% CI = 11-19%). Many participants (35%, 95% CI = 29-40%) also turned to traditional healers. Students who treated snakebite injuries within the last 5 years (N = 69) also reported their general experiences with snakebite in hospitals. Hospitals often lacked essential resources to treat snakebite victims, and 44% (95% CI = 30-59%) of snakebite victims arrived at a hospital only three or more hours after the bite. A significant percentage of snakebite victims experienced lasting damage (32%, 95% CI = 20-47%) or death (14%, 95% CI = 7-25%). Snakebite outcomes could likely be improved if hospitals were universally and consistently equipped with the essential resources to treat snakebite victims, such as antivenoms. Educational interventions aimed at communities should focus on discouraging tourniquet use and tampering with the wound. Collaboration between the allopathic and traditional health system could further boost snakebite outcomes because traditional healers are often the first health workers to see snakebite victims.


Assuntos
Mordeduras de Serpentes , Antivenenos/uso terapêutico , Estudos Transversais , Hospitais , Humanos , Doenças Negligenciadas , Mordeduras de Serpentes/epidemiologia , Mordeduras de Serpentes/terapia , Tanzânia/epidemiologia
11.
Protein Sci ; 31(5): e4296, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35481650

RESUMO

Each year, thousands of people fall victim to envenomings caused by cobras. These incidents often result in death due to paralysis caused by α-neurotoxins from the three-finger toxin (3FTx) family, which are abundant in elapid venoms. Due to their small size, 3FTxs are among the snake toxins that are most poorly neutralized by current antivenoms, which are based on polyclonal antibodies of equine or ovine origin. While antivenoms have saved countless lives since their development in the late 18th century, an opportunity now exists to improve snakebite envenoming therapy via the application of new biotechnological methods, particularly by developing monoclonal antibodies against poorly neutralized α-neurotoxins. Here, we describe the use of phage-displayed synthetic antibody libraries and the development and characterization of six synthetic antibodies built on a human IgG framework and developed against α-cobratoxin - the most abundant long-chain α-neurotoxin from Naja kaouthia venom. The synthetic antibodies exhibited sub-nanomolar affinities to α-cobratoxin and neutralized the curare-mimetic effect of the toxin in vitro. These results demonstrate that phage display technology based on synthetic repertoires can be used to rapidly develop human antibodies with drug-grade potencies as inhibitors of venom toxins.


Assuntos
Proteínas Neurotóxicas de Elapídeos , Naja naja , Animais , Antivenenos/farmacologia , Proteínas Neurotóxicas de Elapídeos/farmacologia , Cavalos , Humanos , Naja naja/metabolismo , Neurotoxinas/química , Neurotoxinas/metabolismo , Ovinos
12.
Toxicon ; 212: 49-54, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35413335

RESUMO

BACKGROUND: Rattlesnake envenomation may lead to a multitude of clinical effects, including a late onset hemorrhage. Laboratory values such as platelets and fibrinogen are commonly used to assess the risk of developing a life-threatening bleed. To date, no specific threshold has been identified that links a lab value to the risk of bleeding. This has led to widespread practice variability among clinicians managing snake bites. In assessing risk for patients, we apply the concept that the more abnormal the lab values are, the higher the risk probably is. Late onset coagulopathies pose a unique clinical challenge because they indicate the potential risk for a life-threatening hemorrhage, yet they have been identified after hospital discharge. There are currently two antivenom (AV) products on the US market to treat rattlesnake envenomations, a Fab product, CroFab® (BTG, UK) and a F (ab')2 product, Anavip® (Bioclon, Mexico). OBJECTIVE: This study intended to characterize the incidence and severity of late coagulopathies reported to a Regional Poison Center (RPC) and hypothesized that late coagulopathies occur at rates higher than previously reported in the literature. Additionally, we sought to compare rates of late coagulopathy between Fab and F (ab')2 AV. METHODS: The investigators performed an in-depth review of all suspected snakebite envenomations from 2018 to 2020 that presented to an Arizona healthcare facility in the RPC's catchment area between January 2018 through December of 2020. Patients were excluded from analysis if they did not receive any antivenom, had an incomplete medical record with the APDIC, were diagnosed as something other than a rattlesnake bite or had a known medical history that clouded the diagnosis or assessment of a rattlesnake envenomation. RESULTS: In total, 522 records were reviewed of which 283 patients met the inclusion criteria. There were 149 patients who received Fab AV and 134 who received F (ab')2. No significant baseline or demographic differences existed between the groups. 95 of the 283 patients developed a late onset coagulopathy. 39% of the late onset coagulopathies were delayed, 32% were recurrent and 29% were persistent. When comparing the two different AV products, delayed or recurrent coagulopathies occurred in 36% of Fab AV- and 10% of F (ab')2 treated patients. Persistent coagulopathies occurred in 17% of Fab AV- and 8% of F (ab')2 treated patients. Interestingly, there were zero cases of late hypofibrinogenemia in any of the 134 F (ab')2 treated patients compared to 26% of all Fab treated ones. The average onset of late coagulopathy post-bite was 8 days for Fab AV and 7 for F (ab')2. CONCLUSION: The results from this study suggest the total rate of late onset coagulopathies may be underestimated. Additionally, our results suggest the potential that F (ab')2 AV may be associated with fewer late onset coagulopathies, especially late onset hypofibrinogenemia.


Assuntos
Afibrinogenemia , Transtornos da Coagulação Sanguínea , Venenos de Crotalídeos , Mordeduras de Serpentes , Antivenenos/uso terapêutico , Transtornos da Coagulação Sanguínea/tratamento farmacológico , Transtornos da Coagulação Sanguínea/epidemiologia , Venenos de Crotalídeos/toxicidade , Hemorragia/tratamento farmacológico , Humanos , Fragmentos Fab das Imunoglobulinas/uso terapêutico , Mordeduras de Serpentes/complicações , Mordeduras de Serpentes/tratamento farmacológico , Mordeduras de Serpentes/epidemiologia
13.
Toxins (Basel) ; 14(3)2022 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-35324665

RESUMO

Snake envenoming afflicts the Indian subcontinent with the highest rates of mortality (47,000) and morbidity globally. The only effective treatment for snakebites is the administration of antivenom, which is produced by the hyperimmunisation of equines. Commercial Indian antivenoms, however, have been shown to exhibit a poor preclinical performance in neutralising venom, as a result of inter- and intrapopulation snake venom variation. Additionally, their poor dose effectiveness necessitates the administration of larger volumes of antivenom for treatment, leading to several harmful side effects in snakebite victims, including serum sickness and fatal anaphylaxis. In this study, we employed chromatographic purification to enhance the dose efficacy of commercial Indian antivenoms. The efficacy of this 'second-generation' antivenom was comparatively evaluated against six other marketed antivenoms using a number of in vitro and in vivo preclinical assays, which revealed its superior venom recognition capability. Enhanced purity also resulted in significant improvements in dose effectiveness, as the 'second-generation' antivenom exhibited a 3 to 4.5 times increased venom neutralisation potential. Furthermore, preclinical assays revealed the increased effectiveness of the 'second-generation' antivenom in countering morbid effects inflicted by the 'big four' Indian snakes. Thus, we demonstrate the role of simpler purification steps in significantly enhancing the effectiveness of snakebite therapy in regions that are most affected by snakebites.


Assuntos
Antivenenos , Mordeduras de Serpentes , Animais , Antivenenos/química , Antivenenos/uso terapêutico , Cavalos , Índia , Mordeduras de Serpentes/tratamento farmacológico , Venenos de Serpentes/química , Serpentes
14.
Toxins (Basel) ; 14(3)2022 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-35324668

RESUMO

PIVL is a Kunitz-type serine protease inhibitor that was previously characterized from Tunisian snake venom, Macrovipera lebetina transmediterranea. It reduced glioblastoma cells' development and significantly blocked angiogenesis in in-vitro and ex-vivo models. PIVL exerted these effects by interfering with αvß3 integrin. In order to produce a biological active recombinant, the cDNA cloning and expression of PIVL was performed in Escherichia coli (BL21)-DE3 cells using pET-22b (+) vector. The recombinant PIVL protein (rPIVL) was purified by nickel affinity chromatography and has recognized monoclonal anti-His antibody. Functionally, rPIVL exhibited potent anti-tumor cell effects as well as anti-angiogenesis properties. Interestingly, we found that both native PIVL (nPIVL) and rPIVL modulated PI3/AKT and MAPK signaling pathways. In all, our results showed that we have successfully expressed the first active anti-oncogenic snake venom Kunitz-type protease inhibitor that can be a potential therapeutic drug against glioblastoma, in its native or recombinant form.


Assuntos
Antivenenos , Glioblastoma , Glioblastoma/tratamento farmacológico , Humanos , Serina , Inibidores de Serino Proteinase/química , Inibidores de Serino Proteinase/genética , Inibidores de Serino Proteinase/farmacologia , Venenos de Serpentes
15.
PLoS Negl Trop Dis ; 16(3): e0010292, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35344557

RESUMO

Envenoming by the hump-nosed pit viper (Hypnale hypnale) raises concern as it inflicts significant debilitation and death in the Western Ghats of India and in the adjacent island nation of Sri Lanka. In India, its medical significance was realized only during 2007 due to its misidentification as Echis carinatus and sometimes as Daboia russelii. Of late, several case reports have underlined the ineptness of the existing polyvalent anti-venom therapy against H. hypnale envenoming. Currently, H. hypnale bite has remained dreadful in India due to the lack of neutralizing anti-venom therapy. Hence, this study was undertaken to establish a systematic comparative, biochemical, pathological, and immunological properties of Sri Lankan H. hypnale venom alongside Indian E. carinatus, and D. russelii venoms. All three venoms differed markedly in the extent of biochemical activities including proteolytic, deoxyribonuclease, L-amino acid oxidase, 5'-nucleotidase, hyaluronidase, and indirect hemolytic activities. The venoms also differed markedly in their pathological properties such as edema, hemorrhage, myotoxic, cardiotoxic, and coagulant activities. The venoms showed stark differences in their protein banding pattern. Strikingly, the affinity-purified rabbit monovalent anti-venoms prepared against H. hypnale, E. carinatus, and D. russelii venoms readily reacted and neutralized the biochemical and pathological properties of their respective venoms, but they insignificantly cross-reacted with, and thus failed to show paraspecific neutralization of any of the effects of the other two venoms, demonstrating the large degree of variations between these venoms. Further, the Indian therapeutic polyvalent anti-venoms from VINS Bioproducts, and Bharath Serums and Vaccines failed to protect H. hypnale venom-induced lethal effects in mice.


Assuntos
Crotalinae , Víbora de Russell , Viperidae , Animais , Antivenenos/farmacologia , Antivenenos/uso terapêutico , Humanos , Camundongos , Coelhos , Venenos de Víboras
16.
Adv Protein Chem Struct Biol ; 129: 435-477, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35305724

RESUMO

Snakebite envenoming (SBE) leads to significant morbidity and mortality, resulting in over 90,000 deaths and approximately 400,000 amputations annually. In sub-Saharan Africa (SSA) alone, SBE accounts for over 30,000 deaths per annum. Since 2017, SBE has been classified as a priority Neglected Tropical Disease (NTD) by the World Health Organisation (WHO). The major species responsible for mortality from SBE within SSA are from the Bitis, Dendroaspis, Echis and Naja genera. Pharmacologically active toxins such as metalloproteinases, serine proteinases, 3-finger toxins, kunitz-type toxins, and phospholipase A2s are the primary snake venom components. These toxins induce cytotoxicity, coagulopathy, hemorrhage, and neurotoxicity in envenomed victims. Antivenom is currently the only available venom-specific treatment for SBE and contains purified equine or ovine polyclonal antibodies, collected from donor animals repeatedly immunized with low doses of adjuvanted venom. The resulting plasma or serum contains a high titre of specific antibodies, which can then be collected and stored until required. The purified antibodies are either whole IgG, monovalent fragment antibody (Fab) or divalent fragment antibody F(ab')2. Despite pharmacokinetic and pharmacodynamic differences, all three are effective in the treatment of SBE. No antivenom is without adverse reactions but, the level of their impact and severity varies from benign early adverse reactions to the rarely occurring fatal anaphylactic shock. However, the major side effects are largely reversible with immediate administration of adrenaline and corticosteroids. There are 16 different antivenoms marketed within SSA, but the efficacy and safety profiles are only published for less than 50% of these products.


Assuntos
Mordeduras de Serpentes , Viperidae , África ao Sul do Saara , Animais , Antivenenos/farmacologia , Antivenenos/uso terapêutico , Cavalos , Fatores Imunológicos/uso terapêutico , Imunoterapia , Ovinos , Mordeduras de Serpentes/tratamento farmacológico
17.
Artigo em Inglês | MEDLINE | ID: mdl-35248757

RESUMO

The viperid snake genus Bothriechis consists of eleven species distributed among Central and South America, living across low and high-altitude habitats. Despite Bothriechis envenomations being prominent across the Central and South American region, the functional effects of Bothriechis venoms are poorly understood. Thus, the aim of this study was to investigate the coagulotoxic and neurotoxic activities of Bothriechis venoms to fill this knowledge gap. Coagulotoxic investigations revealed Bothriechis nigroviridis and B. schlegelii to have pseudo-procoagulant venom activity, forming weak clots that rapidly break down, thereby depleting fibrinogen levels and thus contributing to a net anticoagulant state. While one sample of B. lateralis also showed weaker pseudo-procoagulant activity, directly clotting fibrinogen, two samples of B. lateralis venom were anticoagulant through the inhibition of thrombin and factor Xa activity. Differential efficacy of PoliVal-ICP antivenom was also observed, with the pseudo-procoagulant effect of B. nigroviridis venom poorly neutralised, despite this same activity in the venom of B. schlegelii being effectively neutralised. Significant specificity of these fibrinogen cleaving toxins was also observed, with no activity upon model amphibian, avian, lizard or rodent plasma observed. However, upon avian plasma the venom of B. nigroviridis exerted a complete anticoagulant effect, in contrast to the pseudo-procoagulant effect seen on human plasma. Neurotoxic investigations revealed B. schlegelii to be unique among the genus in having potent binding to the orthosteric site of the alpha-1 postsynaptic nicotinic acetylcholine receptor (with B. lateralis having a weaker but still discernible effect). This represents the first identification of postsynaptic nAChR neurotoxic activity for Bothriechis. In conclusion this study identifies notable differential activity within the coagulotoxic and postsynaptic neurotoxic activity of Bothriechis venoms, supporting previous research, and highlights the need for further studies with respect to antivenom efficacy as well as coagulotoxin specificity for Bothriechis venoms.


Assuntos
Venenos de Crotalídeos , Viperidae , Animais , Anticoagulantes/toxicidade , Antivenenos/farmacologia , Venenos de Crotalídeos/toxicidade , Fibrinogênio/metabolismo , Árvores/metabolismo , Viperidae/metabolismo
18.
Toxicon ; 211: 36-43, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35317993

RESUMO

Deficient skeletal muscle regeneration, which often leads to permanent sequelae, is a common clinical finding in envenomations caused by snakes of the family Viperidae, such as those of Bothrops alternatus and B. diporus in South America. The causes of such poor muscle regenerative outcome are still incompletely understood. Using a murine experimental model of envenomation by the venoms of these two species, we assessed whether traces of venom components that remain in muscle tissue days after envenomation affect myoblasts and myotube formation in culture. The kinetics of drop in venom concentration in the tissue was assessed by ELISA and Western blot, and by the quantification of venom phospholipase A2 activity. A rapid drop of venom components was observed in muscle, although a band of 58-63 kDa remained even 168 h after venom injection, and venom phospholipase A2 activity was detected in muscle tissue days after envenomation. Muscle homogenates from envenomated animals were cytotoxic to myoblasts in culture and inhibited the formation of myotubes even in conditions where homogenates were devoid of cytotoxicity. These deleterious effects were abrogated when homogenates were incubated with antivenom. Our findings agree with previous observations with the venom of Bothrops asper and provide further evidence that one of the causes of the poor skeletal muscle regeneration after Bothrops sp venom-induced myonecrosis is the deleterious action on myogenic cells of traces of venom components remaining in the tissue.


Assuntos
Bothrops , Venenos de Crotalídeos , Animais , Antivenenos , Venenos de Crotalídeos/toxicidade , Camundongos , Fibras Musculares Esqueléticas , Venenos de Serpentes
19.
Toxicon ; 211: 44-49, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35317994

RESUMO

Mexico is home to an extreme diversity of herpetofauna, with venomous snakes imposing a significant burden upon public health. However, little is known about the pathophysiological venom actions of a number of potentially medically important species, including those from the genera Mixcoatlus and Ophryacus. Our study aimed to fill this knowledge gap by ascertaining the effects of Mixcoatlus melanurus, Ophryacus smaragdinus and Ophryacus sphenophrys venoms upon the coagulation cascade utilising a series of well-validated coagulation assays. While M. melanurus venom exhibited no significant coagulotoxic activities, both O. smaragdinus and O. sphenophrys venoms exerted multiple coagulotoxic activities upon the coagulation cascade which would be contributing towards a net anticoagulant venom activity. O. sphenophrys significantly inhibited the spontaneous clotting of plasma but O. smaragdinus did not. They differed in that O. sphenophrys inhibited the clotting enzymes factor IXa and factor XIa. However, O. smaragdinus was able to inhibit factor Xa in isolation-assays. Both O. smaragdinus and O. sphenophrys degraded fibrinogen, with O. smaragdinus venom causing a significantly weaker fibrinogen clot than O. sphenophrys. In vitro antivenom efficacy assays were undertaken to ascertain the efficacy of Antivipmyn-Tri antivenom (which is made using Bothrops, Crotalus, and Lachesis venoms). This antivenom was chosen due to the phylogenetic uncertain position of the Ophryacus, but with some molecular genetics' studies placing it as sister to Lachesis. Despite the complexity of the antivenom immunising mixture, the anticoagulant activity of O. sphenophrys venom was relatively poorly neutralised by the antivenom. This work contributes to the understanding of the functional activity of Mixcoatlus and Ophryacus venoms, laying a foundation for future work investigating the coagulotoxins present within Ophryacus venoms in addition to providing data useful for the evidence-based design of clinical management strategies for the envenomed patient.


Assuntos
Crotalinae , Viperidae , Animais , Anticoagulantes/farmacologia , Antivenenos/farmacologia , Humanos , Filogenia
20.
Int J Biol Macromol ; 208: 275-287, 2022 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-35331793

RESUMO

The Indian monocled cobra (Naja kaouthia) is one of the most prevalent venomous snakes in northeast India (NEI) and is the cause of many fatalities. The composition of NEI N. kaouthia venom (NkV) was deciphered using two different proteomic approaches: (i) 1D SDS-PAGE coupled to label-free quantification of protein bands using stringent identification criteria and (ii) reversed-phase high-performance liquid chromatography (RP-HPLC) followed by quantification based on area under the RP-HPLC peaks. The proteomic data from both strategies were compared. Proteomic analyses from both workflows identified 32 proteins (toxins) distributed over 10-14 snake venom protein families in NEI NkV. The relative abundances of the venom proteins determined from the analytical workflows coincided with the densitometry band intensities of the NEI NkV. Phospholipase A2 (13.1-16.0%) and three-finger toxins (58.5-64.2%) represented the most abundant enzymatic and non-enzymatic proteins in NEI NkV, respectively. Immuno-cross-reactivity studies by enzyme-linked immunoassay and immunoblot analyses pointed to the poor efficacy of commercial PAVs in recognizing the low molecular mass (<15 kDa) toxins of NEI NkV. Spectrofluorometric titration determined the presence of NEI NkV-specific antibodies in commercial PAV, at a level that was higher than that previously reported for eastern India NkV-specific antibodies in commercial antivenom.


Assuntos
Naja naja , Toxinas Biológicas , Animais , Antivenenos , Venenos Elapídicos/química , Índia , Naja naja/metabolismo , Proteoma/metabolismo , Proteômica/métodos , Toxinas Biológicas/metabolismo , Fluxo de Trabalho
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