Activation of M1 muscarinic acetylcholine receptors by proline-rich oligopeptide 7a (

Background: The bioactive peptides derived from snake venoms of the Viperidae family species have been promising as therapeutic candidates for neuroprotection due to their ability to prevent neuronal cell loss, injury, and death. Therefore, this study aimed to evaluate the cytoprotective effects of a synthetic proline-rich oligopeptide 7a (PRO-7a; <EDGPIPP) from Bothrops jararaca snake, on oxidative stress-induced toxicity in neuronal PC12 cells and astrocyte-like C6 cells. Methods: Both cells were pre-treated for four hours with different concentrations of PRO-7a, submitted to H2O2-induced damage for 20 h, and then the oxidative stress markers were analyzed. Also, two independent neuroprotective mechanisms were investigated: a) L-arginine metabolite generation via argininosuccinate synthetase (AsS) activity regulation to produce agmatine or polyamines with neuroprotective properties; b) M1 mAChR receptor subtype activation pathway to reduce oxidative stress and neuron injury. Results: PRO-7a was not cytoprotective in C6 cells, but potentiated the H2O2-induced damage to cell integrity at a concentration lower than 0.38 μM. However, PRO-7a at 1.56 µM, on the other hand, modified H2O2-induced toxicity in PC12 cells by restoring cell integrity, mitochondrial metabolism, ROS generation, and arginase indirect activity. The α-Methyl-DL-aspartic acid (MDLA) and L-NΩ-Nitroarginine methyl ester (L-Name), specific inhibitors of AsS and nitric oxide synthase (NOS), which catalyzes the synthesis of polyamines and NO from L-arginine, did not suppress PRO-7a-mediated cytoprotection against oxidative stress. It suggested that its mechanism is independent of the production of L-arginine metabolites with neuroprotective properties by increased AsS activity. On the other hand, the neuroprotective effect of PRO-7a was blocked in the presence of dicyclomine hydrochloride (DCH), an M1 mAChR antagonist. Conclusions: For the first time, this work provides evidence that PRO-7a-induced neuroprotection seems to be mediated through M1 mAChR activation in PC12 cells, which reduces oxidative stress independently of AsS activity and L-arginine bioavailability.(AU)

Boletim informativo de toxicologia: acidentes ofídicos / Toxicology Fact Sheet: Snakebites

Os acidentes por animais peçonhentos, especialmente os acidentes ofídicos, foram incluídos pela Organização Mundial da Saúde (OMS) na lista das doenças tropicais negligenciadas que acometem, na maioria das vezes, populações pobres que vivem em áreas rurais, devido à gravidade constituem um problema de saúde pública. O sucesso no tratamento do paciente para que os mesmos não gerem sequelas graves, podendo chegar ao óbito, requer atendimento de forma rápida, com o uso adequado do soro específico quando necessário para cada espécie de serpentes e na quantidade recomendada. Em Goiás as principais serpentes que causam acidente são dos gêneros: Bothrops (jararacas), Crotalus (cascavéis) e Micrurus (coral), são considerados acidentes graves que demandam o uso de soros antivenenos específicos

Accidents by venomous animals, especially snakebites, were included by the World Health Organization (WHO) in the list of neglected tropical diseases that affect, most of the time, poor people living in rural areas, due to the seriousness of a public health problem. . Successful treatment of the patient so that they do not generate serious sequelae, which can lead to death, requires quick care, with the appropriate use of specific serum when necessary for each species of snakes and in the recommended amount. In Goiás, the main snakes that cause accidents are of the genera: Bothrops (jararacas), Crotalus (rattlesnakes) and Micrurus (coral), are considered serious accidents that require the use of specific antivenom serums

Venom composition of Trimeresurus albolabris, T. insularis, T. puniceus and T. purpureomaculatus from Indonesia

Background: Several studies have been published on the characterization of Trimeresurus venoms. However, there is still limited information concerning the venom composition of Trimeresurus species distributed throughout Indonesia, which contributes to significant snakebite envenomation cases. The present study describes a comparative on the composition of T. albolabris, T. insularis, T. puniceus, and T. purpureomaculatus venoms originated from Indonesia. Methods: Protein content in the venom of four Trimeresurus species was determined using Bradford assay, and the venom proteome was elucidated using one-dimension SDS PAGE nano-ESI- LCMS/MS shotgun proteomics. Results: The venom of T. albolabris contained the highest protein content of 11.1 mg/mL, followed by T. puniceus, T. insularis and T. purpureomaculatus venom with 10.7 mg/mL, 8.9 mg/mL and 5.54 mg/mL protein, respectively. In total, our venomic analysis identified 65 proteins belonging to 16 protein families in T. purpureomaculatus; 64 proteins belonging to 18 protein families in T. albolabris; 58 different proteins belonging to 14 protein families in T. puniceus; and 48 different proteins belonging to 14 protein familiesin T. insularis. Four major proteins identified in all venoms belonged to snake venom metalloproteinase, C-type lectin, snake venom serine protease, and phospholipase A2. There were 11 common proteins in all venoms, and T. puniceus venom has the highest number of unique proteins compared to the other three venoms. Cluster analysis of the proteins and venoms showed that T. puniceus venom has the most distinct venom composition. Conclusions: Overall, the results highlighted venom compositional variation of four Trimeresurus spp. from Indonesia. The venoms appear to be highly similar, comprising at least four protein families that correlate with venom's toxin properties and function. This study adds more information on venom variability among Trimeresurus species within the close geographic origin and may contribute to the development of optimum heterologous antivenom.(AU)

Acidentes crotálicos no Brasil: atualidades e perspectivas / Crotalic accidents in Brazil: actualities and perspectives

Introdução: Os acidentes ofídicos são eventos negligenciados em países tropicais e em desenvolvimento, incluindo o Brasil. Serpentes do gênero Crotalus são aquelas que produzem os quadros de maior letalidade no país. Objetivos: Abordar os principais aspectos do acidente por Crotalus, com ênfase na biologia das serpentes, na condução clínica dos eventos mórbidos e nas propriedades terapêuticas da peçonha destes animais. Métodos: Revisão da literatura com estratégia de busca definida, a partir da utilização das bases PubMed, LILACS e SciELO. Resultados: A inoculação da peçonha crotálica produz sinais locais discretos, mas repercussões sistêmicas podem ocorrer, especialmente alterações neurológicas e insuficiência renal aguda. A avaliação laboratorial é importante para auxiliar na distinção de outros acidentes ofídicos e para estimar a gravidade do quadro. O soro anticrotálico precisa ser administrado o mais brevemente possível, a partir da estimativa da quantidade de peçonha inoculada. A maior parte dos agravos ocorre no período chuvoso, acometendo principalmente homens jovens que trabalham na zona rural. A adoção de medidas de proteção e a educação em saúde são estratégias pertinentes para a prevenção e a redução do número de casos. As peçonhas de Crotalus possuem ações antimicrobianas, antiagregantes plaquetárias e aplicabilidade em oftalmologia (estrabismo). Conclusão: O conhecimento dos diferentes aspectos dos acidentes crotálicos é essencial para a adequada abordagem diagnóstica e terapêutica de tais condições mórbidas. As propriedades farmacológicas de componentes da peçonha crotálica deverão ser melhor investigadas nos próximos anos, dadas as possibilidades de utilização para o tratamento de diferentes enfermidades humanas

Introduction: Ophidian accidents are neglected events in tropical and in developing countries, including Brazil. Serpents of the Crotalus genus (rattlesnakes) are those that produce the highest case-fatality in the country. Purpose: to address the main aspects of the accident caused by Crotalus, with emphasis on the snakes biology, the clinical approach to snake bites and the therapeutic properties of the venom of these animals. Methods: literature review with a defined search strategy, using the PubMed, LILACS and SciELO databases. Results: Inoculation of crotalic venom produces discrete local signs, but systemic repercussions can occur, especially neurological alterations and acute renal failure. Laboratory evaluation is important to help distinguish from other ophidian accidents and to estimate the severity of the condition. Anticrotalic serum must be administered as soon as possible, based on the estimated amount of inoculated venom. Most of the morbid events occur in the rainy season (higher temperature), mainly affecting young men who work in rural areas. The adoption of protective measures and health education, aimed at the population most commonly involved, are relevant strategies for preventing and reducing the number of cases. In addition, crotalic venoms have antimicrobial actions, antiplatelets functions and ophthalmological applicability (strabismus). Conclusion: Knowledge of the different aspects of crotalic injuries is essential for an adequate diagnostic and therapeutic approach to such morbid conditions. The pharmacological properties of crotalic venom components should be better investigated in the next few years, given the possibilities of their use for the treatment of different human diseases.

Neutralization of toxic activities of Bothrops asper snake venom by ethnomedicinal plants used in Central America, with emphasis in Guatemala: a review / Neutralización de actividades tóxicas del veneno de la serpiente Bothrops asper por plantas etnomedicinales utilizadas en Centroamérica, con énfasis en Guatemala: Revisión

There are few scientific studies that explore the use of medicinal plants for snakebite envenoming in Central America, although plant-based therapies have been traditionally used in the region. This work reviews the studies conducted in Central America to assess the ability of extracts obtained from plants of local ethnomedical use to inhibit toxic activities of the venom of Bothrops asper, the snake responsible for approximately half of the snakebite envenomings in these countries. The search prioritized the description of the plants used in Guatemala, since most of the studies described in this work were conducted in that country, although references to other countries are included. Information concerning secondary metabolites and other pharmacological activities of these plant species, relevant to the treatment of snakebites, was also described. The literature search was conducted in the Google Scholar, PubMed and Scopus databases and completed with locally available literature. It was found that extracts of 12 plant species inhibited the hemorrhagic effect of the venom and three neutralized the edema-forming activity, while inhibition of proteolytic and phospholipase A2 (PLA2) activities was achieved by three and one plant species, respectively. Only Brownea rosa-de-monte was able to effectively counteract the in vitro coagulant effect of the venom. Some plant extracts screened in Guatemala demonstrated procoagulant or anti-thrombin intrinsic effects that might aggravate the coagulopathy induced by the venom. These findings underscore the need of carrying out scientific studies aimed to validate the inhibitory potential of Central American plant extracts and their metabolites against B. asper venom.

Pocos estudios científicos han explorado el uso de plantas medicinales para el tratamiento del envenenamiento ofídico en Centroamérica, a pesar de que las terapias basadas en plantas son de uso tradicional en la región. Este trabajo recopiló información sobre los estudios realizados en Centroamérica para evaluar la capacidad de extractos de plantas de uso etno-médico para inhibir las actividades tóxicas del veneno de Bothrops asper, la serpiente responsable de aproximadamente la mitad de los envenenamientos ofídicos en Centroamérica. La búsqueda priorizó la descripción de plantas utilizadas en Gua-temala, ya que la mayoría de los estudios aquí descritos fueron realizados en ese país. También se incluyó la descripción de los metabolitos secundarios y otras actividades farmacológicas de las especies evaluadas, que podrían explicar su uso como antiofídicos. La búsqueda de literatura se realizó en las bases de datos de Google Scholar, PubMed, Scopus, y se completó con literatura disponible localmente. Se determinó que 12 extractos de plantas inhibieron el efecto hemorrágico del veneno y tres el efecto edematígeno; la actividad proteolítica fue inhibida por extractos de tres especies y la fosfolipasa A2 (PLA2) por una especie. Solamente Brownea rosa-de-monte demostró inhibir efectivamente el efecto coagulante del veneno in vitro. Algunos extractos de las plantas tamizadas en Guatemala demostraron efectos procoagulantes o anti-trombina intrínsecos, que podrían agravar las alteraciones inducidas por el veneno en la coagulación. Estos hallazgos enfatizan la necesidad de validar el potencial de extractos de plantas centroamericanas y sus metabolitos secundarios para neutralizar el veneno de B. asper.

A novel activity on thymocytes cells exerted by the rattlesnake (Crotalus durissus cumanensis) venom / Nueva actividad de los timocitos estimulada por el veneno de la serpiente de cascabel (Crotalus durissus cumanensis)

Abstract. Introduction: The thymus is active mainly during the neonatal and pre-adolescent periods. Objective: To test naïve thymocytes proliferation and monocytes stimulation. Materials and methods: We collected fresh thymus tissue from neonate mice after surgery. Suspension cells were coated onto Ficoll-Hypaque support. The obtained cells (thymocytes) were cultured measuring the proliferation of naïve T cells stimulated by Crotalus durissus cumanensis (Cdc) venom at sub-lethal doses (20 ng). Then, we supplemented the wells with AlamarBlue™ and incubated them for 5 h to test their proliferation. Mononuclear cells from mice peripheral blood were collected and layered onto the support of the Ficoll-Hypaque solution. We added the thymocytes actively dividing (25 x 105 cells) from cultures stimulated with Cdc venom at 20 ng/well to cultured monocytes freshly obtained from the Ficoll-Hypaque separation. Both cell populations were incubated for 36 h until monocytes matured to macrophages. Results: The naïve thymocytes rapidly proliferated after stimulation with the Cdc venom (NTCdc) and these successively induced the maturation and function of monocytes progenitor cells to mature macrophages, which ingested Chinese ink. Conclusions: The naïve thymocytes proliferated by stimulation with the Cdc venom and subsequently the NT/Cdc induced the rapid maturation and function of monocytes progenitor cells becoming mature macrophages with their phenotypic characteristics.

Resumen. Introducción. El timo es activo principalmente durante los períodos neonatal y preadolescente. Objetivo. Probar la proliferación de los timocitos tempranos y la estimulación de monocitos que producen. Materiales y métodos. Se recogió tejido de timo fresco después de la cirugía de ratones recién nacidos. La suspensión de células se colocó sobre un soporte de Ficoll-Hypaque. Las células obtenidas (timocitos) se cultivaron y se midió la proliferación de células T vírgenes estimuladas por el veneno de Crotalus durissus cumanensis (Cdc) en dosis subletales (20 ng). A continuación, se agregó AlamarBlue™ a los pocillos y se incubaron durante 5 horas para evaluar la proliferación. Se recogieron células mononucleares de sangre periférica de ratones y se colocaron sobre un soporte de solución de Ficoll-Hypaque. Los timocitos que se dividieron activamente (25 x 105 células) a partir de los cultivos estimulados con veneno de Cdc (20 ng/pocillo) y se agregaron a los cultivos de monocitos recién obtenidos de la separación en la solución de Ficoll-Hypaque. Ambas poblaciones celulares se incubaron durante 36 horas hasta que los monocitos maduraron a macrófagos. Resultados Los timocitos tempranos experimentaron una rápida proliferación estimulada por el veneno de Cdc (NTCdc) y, posteriormente, indujeron la maduración y la función de las células progenitoras de monocitos, los cuales maduraron a macrófagos, que se tiñeron con tinta china. Conclusiones. Los timocitos tempranos proliferaron con la estimulación del veneno de Cdc y, posteriormente, el NT/Cdc indujo la maduración rápida y la función de las células progenitoras de monocitos, transformándose en macrófagos con sus características fenotípicas.

P-I metalloproteinases and L-amino acid oxidases from Bothrops species inhibit angiogenesis

Snake venoms are composed of pharmacologically active proteins that are evolutionarily diverse, stable and specific to targets. Hence, venoms have been explored as a source of bioactive molecules in treating numerous diseases. Recent evidences suggest that snake venom proteins may affect the formation of new blood vessels. Excessive angiogenesis has been implicated in several pathologies including tumours, diabetic retinopathy, arthritis, inter alia. In the present study, we have examined the effects of P-I metalloproteinases isolated from Bothrops moojeni (BmMP-1) and Bothrops atrox (BaMP-1) and L-amino acid oxidases (LAAO) isolated from B. moojeni (BmLAAO) and B. atrox (BaLAAO) on biochemical and functional aspects of angiogenesis. Methods: P-I metalloproteinases and LAAO were purified from venom by molecular size exclusion and ion-exchange chromatography and subsequently confirmed using mass spectrometry. The P-I metalloproteinases were characterized by azocaseinolytic, fibrinogenolytic and gelatinase activity and LAAO activity was assessed by enzyme activity on L-amino acids. Influence of these proteins on apoptosis and cell cycle in endothelial cells was analysed by flow cytometry. The angiogenic activity was determined by in vitro 3D spheroid assay, Matrigel tube forming assay, and in vivo agarose plug transformation in mice. Results: P-I metalloproteinases exhibited azocaseinolytic activity, cleaved α and partially β chain of fibrinogen, and displayed catalytic activity on gelatin. LAAO showed differential activity on L-amino acids. Flow cytometry analysis indicated that both P-I metalloproteinases and LAAO arrested the cells in G0/G1 phase and further induced both necrosis and apoptosis in endothelial cells. In vitro, P-I metalloproteinases and LAAO exhibited significant anti-angiogenic properties in 3D spheroid and Matrigel models by reducing sprout outgrowth and tube formation. Using agarose plug transplants in mice harbouring P-I metalloproteinases and LAAO we demonstrated a marked disruption of vasculature at the periphery. Conclusion: Our research suggests that P-I metalloproteinases and LAAO exhibit anti-angiogenic properties in vitro and in vivo.(AU)

In vivo and in vitro prospection of the anti-ophidic properties exercised by the extracts of Jacaranda decurrens L

The research and development of alternative treatments for snakebites (e.g., medicinal plants) is necessary due to the high costs of the existing ones. The effects of the aqueous extracts from Jacaranda decurrens leaves, roots, and xylopodium were analyzed upon the venom-induced (Bothrops spp. and Crotalus spp.) systemic and local toxicity. The extracts were able to partially inhibit the phospholipase activity of the venoms from Bothrops jararacussu and Crotalus durissus terrificus. The myotoxic, edema-inducing, coagulant, and hemorrhagic activities were also inhibited. The SDS-PAGE showed that the venom proteins were intact after their incubation with the extracts. This suggests that the possible mechanism of inhibition is not related to the degradation of the protein but rather to their binding to specific sites of the enzymes. The extracts significantly prolonged the survival time of animals in the lethality assay performed with Crotalus durissus terrificus venom and its toxin (crotoxin). The anti-ophidic activity of medicinal plants may aid in the management of snakebites in distant locations by reducing the victim’s local effects and time to heal.

Inhibición de las actividades proteolítica y fosfolipasa A2 del veneno de Bothrops asper por el extracto etanólico de Neurolaena lobata (L) Cass / Inhibition of proteolytic and phospholipase A2 activities of Bothrops asper venom by the ethanolic extract of Neurolaena lobata (L) Cass

Neurolaena lobata es utilizada tradicionalmente en Centroamérica para tratar la mordedura de serpiente, pero su efectividad para contrarrestar el envenenamiento producido por Bothrops asper ha sido poco estudiada. Se evaluó la capacidad del extracto etanólico de sus hojas para inhibir las actividades proteolítica, fosfolipasa A2 (PLA2; evaluada como hemólisis indirecta) y coagulante del veneno in vitro. El material vegetal fue colectado en Izabal, Guatemala, secado, se hicieron extracciones con etanol y se evaluó la presencia de actividades proteolítica, PLA2 y coagulante in-trínsecas en ensayos de concentración-actividad. Los efectos inhibitorios de la actividad proteolítica y PLA2 del veneno se evaluaron después de pre-incubar concentraciones variables del extracto con concentraciones fijas de veneno. La inhibición de la actividad coagulante del veneno no fue evaluada porque el extracto presentó actividad anticoagulante intrínseca dependiente de la concentración. El extracto inhibió completamente las actividades proteolítica (CE50 = 15.7 µg/µl) y PLA2 (CE50 = 32.5 µg/µl) del veneno. El análisis fitoquímico utilizando ensayos macro y semimicrométricos de cromatografía en capa fina, demostró la presencia de flavonoides, cumarinas, saponinas, taninos, sesquiterpenlactonas y aceites esenciales en el extracto. Su efecto sobre las proteínas del veneno se evaluó por electroforesis SDS-PAGE, mostrando cambios en el patrón electroforético atribuidos a la formación de complejos moleculares con los metabo-litos del extracto. Los resultados indican que el extracto podría inhibir los efectos tóxicos del veneno inducidos por las metaloproteinasas dependientes de zinc (SVMPs) y PLA2s, pero podría afectar las alteraciones en la coagulación, coadyuvando en la desfibrinogenación inducida por el veneno.

Neurolaena lobata has been used by traditional healers in Central America to treat snakebite, but its ability to neutralize Bothrops asper envenomations needs to be proved. This study evaluated the inhibitory potential of the ethanolic extract of the leaves of N. lobata against proteolytic, phospholipase A2 (PLA2) and coagulant activities of the venom in vitro. Leaves were collected in Izabal, Guatemala, dried, extracted with ethanol and concentration-response assays were conducted to detect intrinsic proteolytic, PLA2 (evaluated as indirect hemolysis) and coagulant activities. Assays for anti-proteolytic and anti-PLA2 activities were performed after pre-incubation of several amounts of extract with a fixed concentration of venom. Inhibition assay for the coagulant effect of the venom was not tested because pre-incubation of thrombin with the extract prolonged the clotting time of plasma in a concentration-dependent manner. Proteolytic (EC50 = 15.7 µg/µl) and PLA2 (EC50 = 32.5 µg/µl) activities of the venom resulted completely inhibited by the extract. Phytochemical profiles, determined by micrometric assays and semi microanalysis by thin layer chro-matography, showed the presence of flavonoids, coumarins, saponins, tannins, sesquiterpene lactones and essential oils in the extract. SDS-PAGE was used to assess the action of the extract on the venom proteins. Results showed changes in the electrophoretic profile, probably due to the formation of insoluble complexes with plant specialized metabolites. These findings demonstrated that the extract could be able to inhibit toxic effects triggered by zinc-dependent snake venom metalloproteinases (SVMPs) y PLA2s but might aggravate the alterations induced by the venom in coagulation.

Severe tissue complications in patients of Bothrops snakebite at a tertiary health unit in the Brazilian Amazon: clinical characteristics and associated factors

Abstract INTRODUCTION: Snakebites in the Brazilian Amazon are caused mostly by snakes from the Bothrops genus and envenomated patients may suffer from tissue complications. METHODS: This study aimed to identify risk factors for severe tissue complications (STC) in patients with Bothrops snakebite in the Amazonas state, Brazil. RESULTS: Snakebites that were classified as severe and affected female patients with comorbidities presented greater risks of developing STCs. In addition, hospitalizations of patients with STC exceeded 5 days. CONCLUSIONS: Clinical and epidemiological characteristics can prove essential for assessing the evolution of STC and clinical prognosis of patients with Bothrops snakebites.

Neutralización de la actividad letal del veneno de serpiente Bothrops atrox por suero hiperinmune de llama (Lama glama) / Neutralization of the lethal activity from Bothrops atrox venom by hyperimune llama serum (Lama glama)

RESUMEN Objetivos: Evaluar la capacidad del suero hiperinmune de llama (Lama glama) para neutralizar la letalidad del veneno de la serpiente Bothrops atrox en ratones de laboratorio. Materiales y métodos: Se calculó la dosis letal media (DL50) de un pool de venenos de serpientes de Bothrops atrox de Perú, y se midieron los títulos de anticuerpos por ensayo ELISA; así como la potencia de neutralización del suero inmune por el cálculo de la dosis efectiva media (DE50) durante el periodo de inmunización. Resultados: La DL50 del veneno fue de 3,96 µg/g, similar a otros trabajos realizados en Bothrops atrox en Perú. Los títulos de anticuerpos contra el veneno se incrementan rápidamente en la llama mostrando una rápida respuesta inmune; sin embargo, la capacidad de neutralización se incrementa más lentamente y requiere de varias dosis y refuerzos de las inmunizaciones alcanzado una DE50 de 3,30 µL/g ratón y una potencia de neutralización 3,6 mg/mL después de 15 inmunizaciones. Conclusiones: El suero hiperinmune de llama es capaz de neutralizar la letalidad del veneno de la serpiente Bothrops atrox de Perú en ratones de laboratorio.

ABSTRACT Objectives: To evaluate the capacity of the hyperimmune llama serum (Lama glama) to neutralize the lethal activity of Bothrops atrox venom in laboratory mice. Materials and methods: Mean lethal dose (LD50) was calculated from a Bothrops atrox venom sample pool from Peru. The antibody titers were measured by ELISA assay; and the immune serum neutralization potency was measured by calculating the mean effective dose (ED50) during the immunization period. Results: The venom's LD50 was 3.96 μg/g; similar to what was found in other studies about Bothrops atrox carried out in Peru. The titers of antibodies against the venom increased rapidly in the llama, demonstrating a fast immune response; however, the neutralization capacity increased slowly and required several doses and immunization reinforcements, obtaining a ED50 of 3.30 μL/g mouse and a neutralization potency of 3.6 mg/mL after 15 immunizations. Conclusions: The hyperimmune llama serum is able to neutralize the lethality of the Bothrops atrox venom from Peru in laboratory mice.

Envenomation by Trimeresurus stejnegeri stejnegeri: clinical manifestations, treatment and associated factors for wound necrosis

Trimeresurus stejnegeri stejnegeri bite induces tissue swelling, pain, thrombocytopenia, rhabdomyolysis, and acute renal failure. However, the incidence of coagulopathy, factors associated with wound necrosis, and the appropriate management of this condition have not been well characterized yet. Materials: This study included patients bitten by T. s. stejnegeri that were admitted to the study hospitals from 2001 to 2016. Patient characteristics, laboratory data, and management approaches were compared in victims with and without wound necrosis. Results: A total of 185 patients were evaluated: three patients (1.6%) were asymptomatic; whereas tissue swelling and pain, local ecchymosis, wound necrosis, coagulopathy, thrombocytopenia, rhabdomyolysis, and renal impairment were present in 182, 53, 13, 15, 10, 1, and 3 patients, respectively. One patient died from coagulopathy and hemorrhagic shock. Antivenom was administered to all envenomed patients at a median time of 1.8 h after the bite. The median total dose of antivenom was five vials. Chi-square analysis showed that bitten fingers, using cold packs during first aid, presence of bullae or blisters, lymphangitis or lymphadenitis, local numbness and suspected infection to be significantly associated with wound necrosis. After adjustment using a multivariate logistic regression model, only cold packs as first aid, bulla or blister formation, and wound infection remained significant. Conclusions: The main effects of T. s. stejnegeri envenomation are tissue swelling, pain, and local ecchymosis. We do not recommend the use of cold packs during first aid to reduce wound pain, as this may be a risk factor for wound necrosis. In addition, patients with bulla or blister formation should be carefully examined for subsequent wound necrosis. Antiplatelet use may worsen systemic bleeding. No severe rhabdomyolysis or renal failure was observed in this large case series, we therefore considered that they were not prominent effects of T. s. stejnegeri bite.(AU)

Clinical assessment and pathophysiology of Bothrops venom-related acute kidney injury: a scoping review

Bothrops are one of the most common medically important snakes found in Latin America. Its venom is predominantly hemotoxic and proteolytic, which means that local lesion (edema and redness) and hemorrhagic symptoms are recurrent in envenoming by this snake. Although hemorrhage is usually the major cause of death, snakebite-related acute kidney injury is another potentially fatal clinical complication that may lead to chronic kidney disease. The present review highlights the main studies on Bothrops venom-related acute kidney injury, including observational, cross-sectional, case-control and cohort human studies available up to December 2019. The following descriptors were used according to Medical Subject Headings (MeSH): on Medline/Pubmed and Google Scholar "acute kidney injury" or "kidney disease" and "Bothrops"; on Lilacs and SciELO "kidney disease" or "acute kidney injury" and "Bothrops". Newcastle-Ottawa quality assessment scale was used to appraise the quality of the cross-sectional and cohort studies included. The selection of more severe patients who looked for health care units and tertiary centers is a risk of bias. Due to the methodological heterogeneity of the studies, a critical analysis of the results was performed based on the hypothesis that the design of the included studies influences the incidence of acute kidney injury. Fifteen human studies (total participants 4624) were included according to stablished criteria. The coagulation abnormalities (hemorrhagic symptoms, abnormal fibrinogen and activated partial thromboplastin time) were associated with acute kidney injury in the most recent studies reported. The findings observed in this review provide up-to-date evidence about the acute kidney injury pathogenesis following Bothrops syndrome. Studies pointed out that coagulation abnormalities comprise the major pathway for acute kidney injury development. This review may improve patient management by primary healthcare providers, allowing earlier diagnosis and treatment of Bothrops venom-related acute kidney injury.(AU)

In-depth transcriptome reveals the potential biotechnological application of Bothrops jararaca venom gland

Lack of complete genomic data of Bothrops jararaca impedes molecular biology research focusing on biotechnological applications of venom gland components. Identification of full-length coding regions of genes is crucial for the correct molecular cloning design. Methods: RNA was extracted from the venom gland of one adult female specimen of Bothrops jararaca. Deep sequencing of the mRNA library was performed using Illumina NextSeq 500 platform. De novo assembly of B. jararaca transcriptome was done using Trinity. Annotation was performed using Blast2GO. All predicted proteins after clustering step were blasted against non-redundant protein database of NCBI using BLASTP. Metabolic pathways present in the transcriptome were annotated using the KAAS-KEGG Automatic Annotation Server. Toxins were identified in the B. jararaca predicted proteome using BLASTP against all protein sequences obtained from Animal Toxin Annotation Project from Uniprot KB/Swiss-Pro database. Figures and data visualization were performed using ggplot2 package in R language environment. Results: We described the in-depth transcriptome analysis of B. jararaca venom gland, in which 76,765 de novo assembled isoforms, 96,044 transcribed genes and 41,196 unique proteins were identified. The most abundant transcript was the zinc metalloproteinase-disintegrin-like jararhagin. Moreover, we identified 78 distinct functional classes of proteins, including toxins, inhibitors and tumor suppressors. Other venom proteins identified were the hemolytic lethal factors stonustoxin and verrucotoxin. Conclusion: It is believed that the application of deep sequencing to the analysis of snake venom transcriptomes may represent invaluable insight on their biotechnological potential focusing on candidate molecules.(AU)

Neutrophils activated by BJcuL, a C-type lectin isolated from Bothrops jararacussu venom, decrease the invasion potential of neuroblastoma SK-N-SH cells in vitro

Neuroblastoma is a pediatric tumor with a mortality rate of 40% in the most aggressive cases. Tumor microenvironment components as immune cells contribute to the tumor progression; thereby, the modulation of immune cells to a pro-inflammatory and antitumoral profile could potentialize the immunotherapy, a suggested approach for high-risk patients. Preview studies showed the antitumoral potential of BJcuL, a C- type lectin isolated from Bothrops jararacussu venom. It was able to induce immunomodulatory responses, promoting the rolling and adhesion of leukocytes and the activation of neutrophils. Methods: SK-N-SH cells were incubated with conditioned media (CM) obtained during the treatment of neutrophils with BJcuL and fMLP, a bacteria-derived peptide highly effective for activating neutrophil functions. Then we evaluated the effect of the same stimulation on the co-cultivation of neutrophils and SK-N-SH cells. Tumor cells were tested for viability, migration, and invasion potential. Results: In the viability assay, only neutrophils treated with BJcuL (24 h) and cultivated with SK-N-SH were cytotoxic. Migration of tumor cells decreased when incubated directly (p < 0.001) or indirectly (p < 0.005) with untreated neutrophils. When invasion potential was evaluated, neutrophils incubated with BJcuL reduced the total number of colonies of SK-N-SH cells following co-cultivation for 24 h (p < 0.005). Treatment with CM resulted in decreased anchorage-free survival following 24 h of treatment (p < 0.001). Conclusion: Data demonstrated that SK-N-SH cells maintain their migratory potential in the face of neutrophil modulation by BJcuL, but their invasive capacity was significantly reduced.(AU)

Comparative gender peptidomics of Bothrops atrox venoms: are there differences between them?

Bothrops atrox is known to be the pit viper responsible for most snakebites and human fatalities in the Amazon region. It can be found in a wide geographical area including northern South America, the east of Andes and the Amazon basin. Possibly, due to its wide distribution and generalist feeding, intraspecific venom variation was reported by previous proteomics studies. Sex-based and ontogenetic variations on venom compositions of Bothrops snakes were also subject of proteomic and peptidomic analysis. However, the venom peptidome of B. atrox remains unknown. Methods: We conducted a mass spectrometry-based analysis of the venom peptides of individual male and female specimens combining bottom-up and top-down approaches. Results: We identified in B. atrox a total of 105 native peptides in the mass range of 0.4 to 13.9 kDa. Quantitative analysis showed that phospholipase A2 and bradykinin potentiating peptides were the most abundant peptide families in both genders, whereas disintegrin levels were significantly increased in the venoms of females. Known peptides processed at non-canonical sites and new peptides as the Ba1a, which contains the SVMP BATXSVMPII1 catalytic site, were also revealed in this work. Conclusion: The venom peptidomes of male and female specimens of B. atrox were analyzed by mass spectrometry-based approaches in this work. The study points to differences in disintegrin levels in the venoms of females that may result in distinct pathophysiology of envenomation. Further research is required to explore the potential biological implications of this finding.(AU)

Envenenamientos por mordedura de serpiente en Guatemala: revisión de literatura / Snakebite envenomings in Guatemala: literature review

El accidente ofídico es una enfermedad tropical desatendida que ocasiona un problema de salud pública en el mundo, siendo una de las principales causas de morbilidad y mortalidad en las áreas empobrecidas de América Latina. En Guatemala se distribuyen 23 especies de serpientes venenosas de importancia médica. La composición de los venenos es compleja y diversa, resultando en una variedad de manifestaciones clínicas. Los departamentos con mayor incidencia de ofidismo son Petén, Alta Verapaz, Quiché, Escuintla e Izabal. Estos accidentes afectan más a hombres que a mujeres, siendo la mayoría agricultores; el rango de edad más comprometido es de 10-19 años y principalmente ocurren en miembros inferiores. El tiempo medio que tarda la víctima en llegar al hospital es de 5.6 h, siendo el retraso en la atención médica, un factor de riesgo para severidad y mortalidad. Los servicios de salud en ocasiones no cuentan con recursos idóneos para atender a las víctimas, brindando tratamiento sintomático. Simultáneamente, el tratamiento empírico tiene gran aceptación, sin embargo, los resultados de investigaciones realizadas con algunas plantas de uso común en casos de ofidismo, concluyeron que no es recomendable su uso aislado en el tratamiento del envenenamiento. Dada la falta de información se debe promover más investigación sobre el ofidismo en el país, siendo indispensable la elaboración de una ficha de reporte obligatoria. Además, deben elaborarse guías de tratamiento e identificación de serpientes para uso del personal médico, incluyendo programas de educación a nivel comunitario.

Snakebite envenoming is a neglected tropical disease that causes a public health problem in the world, being one of the main causes of morbidity and mortality in impoverished areas of Latin America. 23 species of poi-sonous snakes of medical importance are distributed in Guatemala. The composition of venoms is complex and diverse, resulting in a variety of clinical manifestations. The departments with the highest incidence of snakebites are Petén, Alta Verapaz, Quiché, Escuintla and Izabal. These accidents affect more men than women, the majo-rity being farmers; the most compromised age range is 10-19 years and they mainly occur in the lower limbs. The average time it takes for the victim to reach the hospital is 5.6 hours, with delay in medical care being a risk factor for severity and mortality. Health services sometimes do not have adequate resources to care for victims, providing symptomatic treatment. Simultaneously, empirical treatment is widely accepted, however, the results of research carried out with some plants commonly used in cases of envenoming concluded that their isolated use is not recommended in the treatment. Given the lack of information, more research on snakebite envenoming in the country should be promoted, making the preparation of a mandatory report form essential. In addition, snake identification and treatment guides should be developed for use by medical personnel, including education pro-grams at the community level.

Crotamine in Crotalus durissus: distribution according to subspecies and geographic origin, in captivity or nature

Abstract Background: Crotalus durissus is considered one of the most important species of venomous snakes in Brazil, due to the high mortality of its snakebites. The venom of Crotalus durissus contains four main toxins: crotoxin, convulxin, gyroxin and crotamine. Venoms can vary in their crotamine content, being crotamine-negative or -positive. This heterogeneity is of great importance for producing antivenom, due to their different mechanisms of action. The possibility that antivenom produced by Butantan Institute might have a different immunorecognition capacity between crotamine-negative and crotamine-positive C. durissus venoms instigated us to investigate the differences between these two venom groups. Methods: The presence of crotamine was analyzed by SDS-PAGE, western blotting and ELISA, whereas comparison between the two types of venoms was carried out through HPLC, mass spectrometry analysis as well as assessment of antivenom lethality and efficacy. Results: The results showed a variation in the presence of crotamine among the subspecies and the geographic origin of snakes from nature, but not in captive snakes. Regarding differences between crotamine-positive and -negative venoms, some exclusive proteins are found in each pool and the crotamine-negative pool presented more phospholipase A2 than crotamine-positive pool. This variation could affect the time to death, but the lethal and effective dose were not affected. Conclusion: These differences between venom pools indicate the importance of using both, crotamine-positive and crotamine-negative venoms, to produce the antivenom.(AU)

Alteraciones hemostáticas provocadas por el veneno de la culebra mapanare (Porthidium lansbergii hutmanni) en pacientes venezolanos / Haemostatic alterations caused by the venom of Lansberg's hognosed pitviper (Porthidium lansbergii hutmanni) in Venezuelan patients

Objective: to describe the haemostatic characteristics of the venom as well as the potency appraisal of the polyvalent antiophidic serum against haemotoxicity from Porthidium lansbergii hutmani experimental envenomation. Methods: Evaluation was performed of the venom's lethality, haemorrhagic activity, effects on coagulation and platelet aggregation, proteolytic activity, and neutralization by the commercial antivenom available in the country. Results: Several components with haemostatic activities were found in Porthidium l. hutmanni venom when a study of fibrinogenolytic, haemorrhagic and proteolytic activities was conducted of a pool of P.l.h venom. Porthidium l. hutmanni venom lacked the coagulant and defibrinating activities that are characteristic of bothropic venoms. Porthidium l. hutmanni venom showed very high haemorrhagic and anticoagulant activities. These findings could be related to the presence of multiple metalloproteases, which was evidenced in this study, and also the possible presence of phospholipases or other anticoagulant activity proteins that were not defined here. They inhibited platelet aggregation, suggesting that the venom had some proteins with marked effects on haemostasis. The commercial antivenom proved to be of little effectiveness in neutralizing the crude venom haemorrhagic activity. Conclusions: These toxins cause many physiopathological alterations in bitten patients, creating a clinical picture characterized by oedema, local and systemic haemorrhages, and even necrosis, comparable to that seen in bothropic envenomation. Porthidium l. hutmanni venom has no in vitro procoagulant activity, typical of bothropic venoms, suggesting there are variances in its protein conformation. Porthidium l. hutmanni venom is used for horse immunization. However, in order to preserve the patient's life, it is necessary to improve the immunization process to produce antivenom containing high avidity and specificity antibodies against the major toxins present in this venom. Porthidium l. hutmanni venom has demonstrated being a venom with high lethal, haemorrhagic, proteolytic and procoagulant activities, whose description will have enormous utility among clinicians who deal with these accidents in its geographical distribution areas(AU)

Objetivo: Describir las características hemostáticas del veneno y evaluar la potencia del suero polivalente antiofídico contra la hemotoxicidad provocada por el envenenamiento experimental por Porthidium lansbergii hutmanni. Métodos: Se realizó una evaluación de la letalidad, actividad hemorrágica, efectos en la coagulación y agregación plaquetaria, actividad proteolítica y neutralización por el antiveneno disponible comercialmente en el país. Resultados: Se encontraron varios componentes con actividad hemostática en el veneno de Porthidium l. hutmanni al realizarse un estudio de la actividad fibrinogenolítica, hemorrágica y proteolítica de una muestra de veneno de Porthidium l. hutmanni. El veneno de Porthidium l. hutmanni no mostró la actividad coagulante o defibrinante característica de los venenos botrópicos. El veneno de Porthidium l. hutmanni mostró una elevada actividad hemorrágica y anticoagulante. Estos resultados podrían estar relacionados con la presencia de múltiples metaloproteasas, la que quedó demostrado en el estudio, y también a la posible presencia de fosfolipasas u otras proteínas de actividad anticoagulante que no se definen en el mismo. La inhibición de la agregación plaquetaria sugiere que el veneno contiene algunas proteínas con un marcado efecto sobre la hemostasis. El antiveneno comercial mostró poca efectividad en la neutralización de la actividad hemorrágica del veneno crudo. Conclusiones: Estas toxinas provocan muchas alteraciones fisiopatológicas en las víctimas de mordeduras, creando un cuadro clínico caracterizado por edema, hemorragias locales y sistémicas e incluso necrosis comparable con la que ocurre en el envenenamiento botrópico. El veneno de Porthidium l. hutmanni no tiene la actividad procoagulante in vitro típica de los venenos botrópicos, lo que apunta a variaciones en su conformación proteica. El veneno de Porthidium l. hutmanni de utiliza en la inmunización de los caballos. Sin embargo, para preservar la vida del paciente, es necesario mejorar el proceso de inmunización con vistas a producir un antiveneno que contenga anticuerpos de elevada avidez y especificidad contra las principales toxinas presentes en el veneno. El veneno de Porthidium l. hutmanni ha mostrado ser un veneno de elevada actividad letal, hemorrágica, proteolítica y procoagulante, cuya descripción tendrá una enorme utilidad para los médicos que atienden esos accidentes en sus áreas de distribución geográfica(AU)

Bothrops alternatus snake venom induces apoptosis of skeletal muscle cells in a rabbit model / O veneno da serpente Bothrops alternatus induz apoptose nas células musculares de coelhos

Este estudo objetiva reportar a ocorrência de apoptose in vivo induzida pelo veneno da serpente Bothrops alternatus em células musculares esqueléticas. Cinco coelhos machos, adultos, receberam 150µg/kg de veneno no músculo vasto lateral, enquanto outros cinco animais receberam 0,1% de BSA diluído em PBS no mesmo local. Após 12 horas, os animais foram eutanasiados, e amostras do local de inoculação foram coletadas para análise histopatológica. Foram evidenciadas necrose e hemorragia nas células musculares. Além disso, a análise imuno-histoquímica para identificação de caspase-3 ativada revelou marcações granulares e agregadas no citoplasma das células musculares, compatíveis com o processo de apoptose. Este é o primeiro relato que confirma o veneno de B. alternatus como causador de apoptose in vivo em células musculares esqueléticas.(AU)