Toxinological profile and histopathological alterations induced by Bothrocophias campbelli venom from Colombia.

Snakebite envenomings most frequently reported in Colombia are caused by snakes of the genera Bothrops, Bothriechis, Bothrocophias, and Porthidium. Their venoms induce local and systemic pathophysiological effects, sometimes leading to permanent sequelae such as reduced mobility of the limbs, amputations, besides the risk of death. The genus Bothrocophias includes nine species, among which B. campbelli has a distribution restricted to the department of Nariño in Colombia. In this work we determined the toxinological profile its venom, by performing assays for the lethal, hemorrhagic, edematogenic, and myotoxic activities in mouse models, as well as for in vitro coagulant activity on human plasma. The lethal toxicity of the venom was 142.7 µg venom/mouse (111.4-179.8 µg/mouse; 6.6-10.6 µg/g body weight) by intraperitoneal route. Its hemorrhagic activity (minimum hemorrhagic dose: 12.7 ± 2.3 µg) is generally weaker compared to other South American vipers, but edematogenic (minimum edematogenic dose 1.0 ± 0.3 µg), and myotoxic (minimum myotoxic dose 3.9 ± 2.5 µg) activities are very potent. Histopathological examination of the injected mouse gastrocnemius muscle showed prominent disorganization of the myofibrils, myonecrosis, and an intense inflammatory leukocyte infiltrate. In vitro, the minimal coagulant dose was 12.3 ± 0.5 µg. Overall, this toxinological profile would predict that the clinical picture of envenomings by B. campbelli might be characterized by moderate disturbances in the coagulation cascade, mild local hemorrhage, and, conversely, severe myonecrosis and edema, which could potentially lead to compartment syndrome and gangrene.

Half a century of research on Bothrops asper venom variation: biological and biomedical implications.

Snake venoms are a complex biological mixture of proteins with or without enzymatic activity, peptides, and nucleotides, among other components. It is produced in specialized secretory glands located in the maxillary region, being the result of millions of years of evolution and whose biological functions are defense, immobilization, and digestion of prey. Venoms present intraspecific (i.e., individual, ontogenetic, geographical) and interspecific (i.e., between sympatric and allopatric species) variation, and the study of this variability has become the focus of toxinological research. Bothrops asper is responsible for highest incidence, morbimortality and severe cases of envenoming in Mesoamerica and northern South America. Given its clinical importance, its venom has been characterized and compared qualitatively and quantitatively across the species range. More than 50 years of research show that B. asper venom is endowed with an interesting intraspecific variability. Knowing this variation has allowed advances in the elucidation of the biological role of the venom, a better understanding of the clinical signs and symptoms in patients envenomed by B asper, the immunological implications in the context of antivenoms production, and the generation of new ideas that could be useful to solve different biological and evolutionary questions of one of the venomous snakes with the greatest distribution and strongest public health impact in Latin America.

What's in a mass?

This short essay pretends to make the reader reflect on the concept of biological mass and on the added value that the determination of this molecular property of a protein brings to the interpretation of evolutionary and translational snake venomics research. Starting from the premise that the amino acid sequence is the most distinctive primary molecular characteristics of any protein, the thesis underlying the first part of this essay is that the isotopic distribution of a protein's molecular mass serves to unambiguously differentiate it from any other of an organism's proteome. In the second part of the essay, we discuss examples of collaborative projects among our laboratories, where mass profiling of snake venom PLA2 across conspecific populations played a key role revealing dispersal routes that determined the current phylogeographic pattern of the species.

Antivenomics and in vivo preclinical efficacy of six Latin American antivenoms towards south-western Colombian Bothrops asper lineage venoms.

BACKGROUND: Bothrops asper represents the clinically most important snake species in Central America and Northern South America, where it is responsible for an estimated 50-80% of snakebites. Compositional variability among the venom proteomes of B. asper lineages across its wide range mirrors clinical differences in their envenomings. Bothropic antivenoms generated in a number of Latin American countries commonly exhibit a certain degree of paraspecific effectiveness in the neutralization of congeneric venoms. Defining the phylogeographic boundaries of an antivenom's effectivity has implications for optimizing its clinical use. However, the molecular bases and impact of venom compositions on the immune recognition and neutralization of the toxic activities of across geographically disparate populations of B. asper lineages has not been comprehensively studied. METHODOLOGY/PRINCIPAL FINDINGS: Third-generation antivenomics was applied to quantify the cross-immunorecognizing capacity against the individual components of venoms of three B. asper lineages (B. asper (sensu stricto), B. ayerbei and B. rhombeatus) distributed in south-western (SW) Colombia, of six Latin American antivenoms, produced against homologous (Colombia, INS-COL and PROBIOL) and Costa Rica (ICP)), and heterologous (Argentina (BIOL), Perú (INS-PERU) and Venezuela (UCV)) bothropic venoms. In vivo neutralization assays of the lethal, hemorrhagic, coagulant, defibrinogenating, myotoxic, edematogenic, indirect hemolytic, and proteolytic activities of the three SW Colombian B. asper lineage venoms were carried to compare the preclinical efficacy of three (Colombian INS-COL and PROBIOL, and Costa Rican ICP) antivenoms frequently used in Colombia. Antivenomics showed that all the six antivenom affinity matrices efficiently immunoretained most of the B. asper lineages venom proteins and exhibited impaired binding towards the venoms' peptidomes. The neutralization profile of the INS-COL, PROBIOL and ICP antivenoms towards the biological activities of the venoms of SW Colombian B. asper (sensu stricto), B. ayerbei and B. rhombeatus lineages was coherent with the antivenomics outcome. In addition, the combination of in vitro (antivenomics) and in vivo neutralization results allowed us to determine their toxin-specific and venom neutralizing antibody content. Noteworthy, heterologous INS-PERU, BIOL, and UCV bothropic antivenoms had equal or higher binding capacity towards the venoms components of SW Colombian B. asper lineages that the homologous Colombian and Costa Rican antivenoms. CONCLUSIONS/SIGNIFICANCE: The combined in vitro and in vivo preclinical outcome showed that antivenoms manufactured in Colombia and Costa Rica effectively neutralize the major toxic activities of SW Colombian B. asper lineage venoms. The antivenomics profiles of the heterologous antivenoms manufactured in Argentina, Venezuela, and Perú strongly suggests their (pre)clinical adequacy for the treatment of B. asper lineage envenomings in SW Colombia. However, their recommendation in the clinical setting is pending on in vivo neutralization testing and clinical testing in humans. Bothrops asper is a highly adaptable snake species complex, which is considered the most dangerous snake throughout much of its distribution range from the Atlantic lowland of eastern México to northwestern Perú. Antivenoms are the only scientifically validated treatment of snakebite envenomings. Venom variation is particularly common in wide ranging species, such as B. asper, and may result in variable clinical presentations of envenomings, as is the case for the B. asper species complex, potentially undermining the efficacy of snakebite treatments depending on the immunization mixture used in the generation of the antivenom. Conversely, phylogenetic conservation of antigenic determinants confers an unpredictable degree of paraspecificity to homologous antivenoms produced for a geographic area, but also to heterologous congeneric antivenoms, towards the venom components of allopatric conspecific populations. This work aimed at comparing the preclinical profile of a panel of Latin American homologous and heterologous antivenoms against the venoms of B. asper lineages distributed in SW Colombia. The outcome of this study strongly suggests the suitability of considering the heterologous antivenoms BIOL (Argentina), UCV (Venezuela) and INS-PERU (Perú) as alternatives to homologous Colombian INS-COL and PROBIOL and Costa Rican ICP antivenoms for the treatment of envenomings by B. asper (sensu stricto) in W Colombia and Ecuador, B. ayerbei in Cauca and Nariño (Colombia), and B. rhombeatus in Cauca river valley, SW Colombia.

What's in a mass?

This short essay pretends to make the reader reflect on the concept of biological mass and on the added value that the determination of this molecular property of a protein brings to the interpretation of evolutionary and translational snake venomics research. Starting from the premise that the amino acid sequence is the most distinctive primary molecular characteristics of any protein, the thesis underlying the first part of this essay is that the isotopic distribution of a protein's molecular mass serves to unambiguously differentiate it from any other of an organism's proteome. In the second part of the essay, we discuss examples of collaborative projects among our laboratories, where mass profiling of snake venom PLA2 across conspecific populations played a key role revealing dispersal routes that determined the current phylogeographic pattern of the species.

Venom variation in Bothrops asper lineages from North-Western South America.

Bothrops asper is a venomous pitviper that is widely distributed and of clinical importance in Mesoamerica and northern South America, where it is responsible for 50-80% of all envenomations by Viperidae species. Previous work suggests that B. asper has a complex phylogeographic structure, with the existence of multiple evolutionarily distinct lineages, particularly in the inter-Andean valleys of north South America. To explore the impact of the evolutionary history of B. asper on venom composition, we have investigated geographic variation in the venom proteome of this species from the populations from the Pacific side of Ecuador and south-western Colombia. Among the 21 classes of venom components identified, proteins from mainly four major toxin families, snake venom metalloproteases (PI- and PII-SVMP), phospholipases A2 (K49- and D49-PLA2s), serine proteinases (SVSP), and C-type lectins-like (CTL) proteins are major contributors to the geographic variability in venom. Principal component analyses demonstrate significant differences in venom composition between B. asper lineages previously identified through combination of molecular, morphological and geographical data, and provide additional insights into the selection pressures modulating venom phenotypes on a geographic scale. In particular, altitudinal zonation within the Andean mountain range stands out as a key ecological factor promoting diversification in venom. In addition, the pattern of distribution of PLA2 molecules among B. asper venoms complements phylogenetic analysis in the reconstruction of the dispersal events that account for the current biogeographic distribution of the present-day species' phylogroups. Ontogenic variation was also evident among venoms from some Ecuadorian lineages, although this age-related variation was less extreme than reported in B. asper venoms from Costa Rica. The results of our study demonstrate a significant impact of phylogenetic history on venom composition in a pitviper and show how analyses of this variation can illuminate the timing of the cladogenesis and ecological events that shaped the current distribution of B. asper lineages. BIOLOGICAL SIGNIFICANCE: Bothrops asper, called "the ultimate pitviper" due to its defensive behavior, large body size, and medical importance, represents a species complex that is widely distributed from southern México southwards across north-western South America to north-western Perú. This work reports the characterization of the venom proteomes of B. asper lineages from the Pacific sides of Ecuador and south-western Colombia. Multivariate analyses indicate that variability in venom composition among the B. asper lineages is driven by proteins from four major toxin families, presumably in response to selection pressures created by recent and historical ecological conditions created by geological and climatic events from the Pliocene-Pleistocene to the present along the Central and South American Continental Divide. The emerging biogeographic pattern of venom variation, interpreted in the context of the current phylogenetic hypotheses, support and complement previously proposed evolutionary Plio-Pleistocene dispersal events that shaped the present-day distribution range of B. asper lineages. In addition, our venomics data indicate the occurrence of genetic exchange between Colombian and Pacific Costa Rican populations, which may have occurred during the second wave of B. asper migration into Mesoamerica. Our work represents a foundation for a future broader sampling and more complete "-omics" analyses to deepen our understanding of the patterns and causes of venom variation in this medically important pitviper.

Snakebite in the department of Nariño, Colombia: a retrospective analysis, 2008-2017 / Accidente ofídico en el departamento de Nariño, Colombia: análisis retrospectivo, 2008-2017

Introduction. Snakebite envenoming is a relevant public health problem, and, in Colombia, it was included as a mandatory notification event since 2004. Because it is a tropical country with great ecosystem diversity, it occupies third place in Latin America, after Mexico and Brazil, reaching the highest number of snakebites. Objective. To carry out a retrospective analysis of snakebites in the department of Nariño based on the notifications reported to the Instituto Departamental de Salud de Nariño and the Sistema de Vigilancia en Salud Pública de Colombia between the years 2008 and 2017. Materials and methods. A descriptive and retrospective analysis was carried out based on the study, and interpretation of the information contained in the notification sheets for ophidian accidents of the Instituto Departamental de Salud de Nariño between the years 2008 and 2017. The snakebite frequency at the municipal level was represented by the elaboration of a map and the responsible genus were identified. Results. A total of 1,110 cases were reported for ophidian accidents. Seventy- eight point thirteen per cent of the municipalities made some notification. A pattern of constant increase in the case number during the 10 years is evident, with exception of 2017; the sociodemographic characteristics are maintained. Conclusions. The municipality of San Andrés de Tumaco, the masculine gender and the rural areas are mostly affected by snakebites, caused mainly by the Bothrops genus and the highest snakebite incidence was seen in July.

Introducción. El ofidismo es un relevante problema de salud pública y, en Colombia, se incluyó como un evento de notificación obligatoria desde el año 2004. Por ser un país tropical con gran diversidad ecosistémica, ocupa el tercer puesto en Latinoamérica, después de México y Brasil, en presentar el mayor número de accidentes ofídicos. Objetivo. Realizar un análisis retrospectivo del accidente ofídico en el departamento de Nariño, con base en los eventos notificados entre los años 2008 y 2017 al Instituto Departamental de Salud de Nariño y al Sistema de Vigilancia en Salud Pública de Colombia. Materiales y métodos. Se hizo un análisis de tipo descriptivo y retrospectivo a partir de la recopilación e interpretación de la información consignada en las fichas de notificación para accidente ofídico del Instituto Departamental de Salud de Nariño, entre los años 2008 y 2017. Se representó la frecuencia del accidente ofídico a nivel municipal mediante la elaboración de un mapa y se identificaron los géneros responsables del mismo. Resultados. Se reporta un total de 1.110 casos. El 78,13 % de los municipios hizo alguna notificación. Se observa un patrón de aumento constante en el número de casos durante los 10 años, a excepción de 2017. Las características sociodemográficas se mantuvieron durante el periodo de estudio. Conclusiones. El municipio de San Andrés de Tumaco, el sexo masculino y las áreas rurales son los principales afectados por el ofidismo causado, en mayor medida, por el género Bothrops. La mayor incidencia se presentó en el mes de julio.

Accidente ofídico en el departamento de Nariño, Colombia: análisis retrospectivo, 2008-2017 / Snakebite in the department of Nariño, Colombia: a retrospective analysis, 2008-2017

Introducción. El ofidismo es un relevante problema de salud pública y, en Colombia, se incluyó como un evento de notificación obligatoria desde el año 2004. Por ser un país tropical con gran diversidad ecosistémica, ocupa el tercer puesto en Latinoamérica, después de México y Brasil, en presentar el mayor número de accidentes ofídicos. Objetivo. Realizar un análisis retrospectivo del accidente ofídico en el departamento de Nariño, con base en los eventos notificados entre los años 2008 y 2017 al Instituto Departamental de Salud de Nariño y al Sistema de Vigilancia en Salud Pública de Colombia. Materiales y métodos. Se hizo un análisis de tipo descriptivo y retrospectivo a partir de la recopilación e interpretación de la información consignada en las fichas de notificación para accidente ofídico del Instituto Departamental de Salud de Nariño, entre los años 2008 y 2017. Se representó la frecuencia del accidente ofídico a nivel municipal mediante la elaboración de un mapa y se identificaron los géneros responsables del mismo. Resultados. Se reporta un total de 1.110 casos. El 78,13 % de los municipios hizo alguna notificación. Se observa un patrón de aumento constante en el número de casos durante los 10 años, a excepción de 2017. Las características sociodemográficas se mantuvieron durante el periodo de estudio. Conclusiones. El municipio de San Andrés de Tumaco, el sexo masculino y las áreas rurales son los principales afectados por el ofidismo causado, en mayor medida, por el género Bothrops. La mayor incidencia se presentó en el mes de julio.

Introduction. Snakebite envenoming is a relevant public health problem, and, in Colombia, it was included as a mandatory notification event since 2004. Because it is a tropical country with great ecosystem diversity, it occupies third place in Latin America, after Mexico and Brazil, reaching the highest number of snakebites. Objective. To carry out a retrospective analysis of snakebites in the department of Nariño based on the notifications reported to the Instituto Departamental de Salud de Nariño and the Sistema de Vigilancia en Salud Pública de Colombia between the years 2008 and 2017. Materials and methods. A descriptive and retrospective analysis was carried out based on the study, and interpretation of the information contained in the notification sheets for ophidian accidents of the Instituto Departamental de Salud de Nariño between the years 2008 and 2017. The snakebite frequency at the municipal level was represented by the elaboration of a map and the responsible genus were identified. Results. A total of 1,110 cases were reported for ophidian accidents. Seventy- eight point thirteen per cent of the municipalities made some notification. A pattern of constant increase in the case number during the 10 years is evident, with exception of 2017; the sociodemographic characteristics are maintained. Conclusions. The municipality of San Andrés de Tumaco, the masculine gender and the rural areas are mostly affected by snakebites, caused mainly by the Bothrops genus and the highest snakebite incidence was seen in July.

Síndrome de Brugada. Aspectos fisiopatológicos, clínicos y su asociación con enfermedades infecciosas / Brugada syndrome. Physiopathological, clinical aspects and association with infectious diseases

RESUMEN El síndrome de Brugada (SBr) es una enfermedad cardiaca no estructural que afecta los canales iónicos cardiacos, caracterizado por manifestaciones clínicas como arritmias, taquicardia, síncope y muerte súbita, entre otras. Su diagnóstico es netamente electrocardiográfico, con un patrón altamente sugestivo pero no patognomónico, por lo que existen diagnósticos diferenciales desde el punto de vista electrocardiográfico. Existen tres patrones electrocardiográficos en los pacientes con SBr, de los cuales el tipo I es el patrón más característico. Actualmente, múltiples genes se han relacionado con la presentación de este síndrome, entre los cuales se destaca el gen SCN5A, el más descrito en la literatura. Se conoce que este síndrome es más frecuente en el género masculino; sin embargo, no existen estudios epidemiológicos en Latinoamérica que lo confirmen. Pese a que la investigación alrededor de los mecanismos causales del síndrome ha avanzado, existen varias cuestiones sin resolver, como su desenmascaramiento por los signos que producen algunas enfermedades infecciosas causadas principalmente por virus. Por lo tanto, dada la relevancia clínica del tema para el médico general y para el especialista, el objetivo de esta revisión es describir no solo aspectos fisiopatológicos y clínicos de la enfermedad, sino también resaltar casos de pacientes con enfermedades infecciosas quienes posteriormente han sido diagnosticados con el síndrome de Brugada.

SUMMARY Brugada syndrome (BrS) is a non-structural cardiac disease that affects cardiac ion channels; it is characterized by clinical manifestations such as arrhythmias, tachycardia, syncope and sudden death, among others. Its diagnosis is mainly electrocardiographic, with a highly suggestive but not pathognomonic pattern, thus, there could be differential diagnoses from the electrocardiographic point of view. There are three electrocardiographic patterns in patients with BrS, of which type I is the most characteristic pattern. Currently, multiple genes have be linked to the presentation of this syndrome, among which the SCN5A gene is the most described in the literature. It is know that this syndrome is more frequent in males; however, there are not epidemiological studies in Latin America that confirm it. Although research around the causal mechanisms of the syndrome has advanced, there are several unresolved issues, for example, its unmasking by the signs produced for some infectious diseases caused mainly by viruses. Therefore, given the clinical relevance of the topic, for the medical general practitioner and the specialist, the objective of this review is to describe not only the physiopathological and clinical aspects of the disease, but also highlight cases of patients with infectious diseases, who subsequently have been diagnosed with Brugada syndrome.

Virus de Epstein-Barr y su relación con el desarrollo del cáncer / Relationship between Epstein-Barr virus and cancer development / O Vírus de Epstein-Barr e sua relação com o desenvolvimento do cáncer

RESUMEN El virus de Epstein-Barr (VEB) es un agente infeccioso que tiene tropismo por células linfoides y ocasionalmente por células epiteliales. La Agencia Internacional para la Investigación sobre Cáncer (IARC, por su sigla en inglés) lo clasificó hace 20 años como carcinógeno de tipo I, porque durante la infección latente expresa diferentes proteínas o micro-ARN con capacidad oncogénica, por lo que las células infectadas tendrían el potencial de desarrollar cáncer. Esto se ha demostrado en algunos tipos de cáncer como linfomas, carcinoma nasofaríngeo y cáncer gástrico, mientras que la asociación no es completamente clara en los cánceres de mama y pulmón. La presente revisión describe, profundiza y analiza la relación del VEB con dichos tipos de cáncer, así como los métodos diagnósticos empleados para su detección. Finalmente, se plantean preguntas cuyas respuestas podrían contribuir al conocimiento de los mecanismos moleculares involucrados en la relación VEB-cáncer.

SUMMARY Relationship between Epstein-Barr virus and cancer development Epstein-Barr virus (EBV) is an infectious agent with tropism for lymphoid cells and occasionally for epithelial cells. Twenty years ago it was classified by the International Agency for Research on Cancer (IARC) as type I carcinogen, because during latent infection it expresses different proteins or microRNAs with oncogenic ability, so that infected cells could potentially develop cancer. This association has been shown in some cancers such as lymphoma, nasopharyngeal carcinoma and gastric cancer, while the association has not been completely clear in breast and lung cancer. This review describes, deepens and analyzes the relationship between EVB and the aforementioned types of cancer, as well as diagnostic methods for its detection. Finally, this paper poses different questions whose answers could contribute to understand the molecular mechanisms involved in the EVB-cancer relationship.

RESUMO O vírus de Epstein-Barr (VEB) é um agente infeccioso que tem tropismo pelas células linfóides e, ocasionalmente, por células epiteliais. A Agência Internacional de Investigação do Câncer (IARC, por sua sigla do Inglês) classificou-o há 20 anos como substância cancerígena tipo I, devido a que durante a infecção latente expressa diferentes proteínas ou micro-ARN com capacidade oncogênica, de modo que as células infectadas têm o potencial de desenvolver câncer. Isto tem sido demonstrado em alguns tipos de câncer tais como linfomas, carcinoma da nasofaringe e câncer gástrico, enquanto que a associação não é inteiramente claro nos câncer da mama e do pulmão. Esta revisão descreve, analisa os aprofunda a relação do VEB com os mencionados tipos de câncer, bem como os métodos de diagnóstico para a sua detecção. Finalmente, planteiam se questões cujas respostas poderiam contribuir na compreensão dos mecanismos moleculares envolvidos na relação VEB-câncer.

Infección por el virus linfotrópico humano de células T tipo 1 (HTLV-1) y paraparesia espástica. Avances y diagnóstico 35 años después de su descubrimiento / Human T-lymphotropic virus type 1 (HTLV-1) infection and spastic paraparesis. Advances and diagnosis 35 years after its Discovery / Infecção pelo vírus linfotrópico humano de células T tipo 1 (HTLV-1) e paraparesia espástica. Avanços e diagnóstico depois de 35 anos do seu descobrimento

RESUMEN El virus linfotrópico humano tipo 1 (HTLV-1) genera trastornos como la mielopatía inflamatoria crónica y progresiva conocida como mielopatía asociada al HTLV-1 (MAH), caracterizada por un cuadro clínico de paraparesia espástica. Inicialmente, el virus fue reportado en zonas tropicales y actualmente está presente en diferentes regiones del mundo. El HTLV-1 se puede transmitir tanto horizontal como verticalmente y permanecer latente en los pacientes; se calcula que de 1 % a 5 % de los infectados desarrollan leucemia/linfoma de células T en el adulto (LTA) y de 3 % a 5 %, MAH. Esta revisión, por medio de la búsqueda sistemática en bases de datos, es una compilación de la información más sobresaliente acerca de este retrovirus y la paraparesia espástica, aporta al conocimiento básico de la enfermedad, difunde un problema de salud poco conocido y genera la necesidad de hacer un diagnóstico temprano a fin de intervenir en la cadena de transmisión del virus y evitar su propagación silenciosa en la población.

SUMMARY Human T-lymphotropic virus type 1 (HTLV-1) causes disorders such as chronic inflammatory progressive myelopathy, which is known as HTLV-1associated myelopathy (MAH), characterized by spastic paraparesis symptoms. Originally, the virus was reported in tropical zones and is currently distributed in different regions of the world. HTLV-1 can be transmitted both horizontally and vertically, and remains latent in patients; between 1 % and 5 % of those infected develop adult T cell leukemia/lymphoma (LTA) and 3 % to 5 %, MAH. This review, carried out through systematic search of databases, compiles the most outstanding information about this retrovirus and the spastic paraparesis, provides basic knowledge on the disease, illustrates on an unknown health problem and creates the need for early diagnosis in order to stop the chain of viral infection and prevent its silent propagation among the population.

RESUMO O vírus linfotrópico humano tipo 1 (HTLV-1) gera transtornos como a mielopatia inflamatória crônica e progressiva conhecida como mielopatia associada ao HTLV-1 (MAH), caracterizada por um quadro clínico de paraparesia espástica. Inicialmente, o vírus foi reportado em zonas tropicais e atualmente está presente em diferentes regiões do mundo. O HTLV-1 se pode transmitir tanto horizontal como verticalmente e permanecer latente nos pacientes; calculase que de 1% a 5% dos infectados desenvolvem leucemia/linfoma de células T no adulto (LTA) e de 3% a 5%, MAH. Esta revisão, por meio da pesquisa sistemática em bases de dados, é uma compilação da informação mais sobressalente sobre este retrovírus e a paraparesia espástica, aporta ao conhecimento básico da doença, difunde um problema de saúde pouco conhecido e gera a necessidade de fazer um diagnóstico precoce com o fim de intervir na cadeia de transmissão do vírus e evitar a sua propagação silenciosa na população.

First crotoxin-like phospholipase A(2) complex from a New World non-rattlesnake species: nigroviriditoxin, from the arboreal Neotropical snake Bothriechis nigroviridis.

Bothriechis nigroviridis is an arboreal Neotropical pitviper found in Costa Rica and Panamá. A previous proteomic profiling of its venom revealed the presence of proteins with homology to the A and B subunits of crotoxin/Mojave toxin, a heterodimeric phospholipase A2 (PLA2) complex only described in rattlesnake venoms (genera Crotalus and Sistrurus). The native crotoxin-like heterodimer, named nigroviriditoxin, and its A and B subunits were isolated in the present work, and the complete amino acid sequence of the B subunit was determined. The purified A and B components were demonstrated to form a complex when reconstituted under native conditions. Nigroviriditoxin presents features similar to crotoxin, albeit displaying lower toxicity: the A component decreases the PLA2 activity of the B component, and increases its lethal potency in mice. Also in similarity to crotoxin B, nigroviriditoxin B induces myonecrosis. Its 122 amino acid sequence presents 81% identity with crotoxin B. Accordingly, nigroviriditoxin B was cross-recognized by equine antibodies from a Crotalus durissus terrificus antivenom. Phylogenetic analysis shows that the novel PLA2 from B. nigroviridis venom is basal to the branch including all the homologous PLA2 enzymes described in rattlesnakes, and more distant from PLA2s from Bothriechis species. Nigroviriditoxin is the first heterodimeric PLA2 complex found in a non-rattlesnake, Neotropical viperid venom, which displays structural, functional, and immunochemical similarities to crotoxin. The present findings are compatible with the existence of the particular structural trait of crotoxin-like molecules in New World pitvipers before the split of the Meso-South American and the Nearctic clades.

Proteomic and functional analyses of the venom of Porthidium lansbergii lansbergii (Lansberg's hognose viper) from the Atlantic Department of Colombia.

The venom of the Lansberg's hognose pitviper, Porthidium lansbergii lansbergii, a species found in the northern region of Colombia, is poorly known. Aiming to increase knowledge on Porthidium species venoms, its proteomic analysis and functional evaluation of in vitro and in vivo activities relevant to its toxicity were undertaken. Out of 51 protein components resolved by a combination of RP-HPLC and SDS-PAGE, 47 were assigned to 12 known protein families. In similarity with two previously characterized venoms from species within this genus, Porthidium nasutum and Porthidium ophryomegas, that of P. lansbergii lansbergii was dominated by metalloproteinases, although in lower proportion. A common feature of the three Porthidium venoms appears to be a high content of disintegrins. Proteins not previously observed in Porthidium venoms belong to the vascular endothelium growth factor, phosphodiesterase, and phospholipase B families. P. lansbergii lansbergii venom showed relatively weak lethal activity to mice, and induced a moderate local myotoxicity, but considerable hemorrhage. Its isolated VEGF component showed potent edema-inducing activity in the mouse footpad assay. Significant thrombocytopenia, but no other major hematological changes, were observed in envenomed mice. In vitro, this venom lacked coagulant effect on human plasma, and induced a potent inhibition of platelet aggregation which was reproduced by its purified disintegrin components. Phospholipase A2 and proteolytic activities were also demonstrated. Overall, the compositional and functional data herein described for the venom of P. lansbergii lansbergii may contribute to a better understanding of envenomings by this pitviper species, for which specific clinical information is lacking. BIOLOGICAL SIGNIFICANCE: Porthidium lansbergii lansbergii is estimated to be responsible for nearly 20% of snakebite envenoming cases at the Atlantic Department of Colombia, but the identity and functional properties of its venom components are largely unknown. This study provides the first combined proteomic and functional analyses of the venom of this pitviper, which may contribute to a better understanding of the features of envenomings by this species.

Synergism between basic Asp49 and Lys49 phospholipase A2 myotoxins of viperid snake venom in vitro and in vivo.

Two subtypes of phospholipases A2 (PLA2s) with the ability to induce myonecrosis, 'Asp49' and 'Lys49' myotoxins, often coexist in viperid snake venoms. Since the latter lack catalytic activity, two different mechanisms are involved in their myotoxicity. A synergism between Asp49 and Lys49 myotoxins from Bothrops asper was previously observed in vitro, enhancing Ca2+ entry and cell death when acting together upon C2C12 myotubes. These observations are extended for the first time in vivo, by demonstrating a clear enhancement of myonecrosis by the combined action of these two toxins in mice. In addition, novel aspects of their synergism were revealed using myotubes. Proportions of Asp49 myotoxin as low as 0.1% of the Lys49 myotoxin are sufficient to enhance cytotoxicity of the latter, but not the opposite. Sublytic amounts of Asp49 myotoxin also enhanced cytotoxicity of a synthetic peptide encompassing the toxic region of Lys49 myotoxin. Asp49 myotoxin rendered myotubes more susceptible to osmotic lysis, whereas Lys49 myotoxin did not. In contrast to myotoxic Asp49 PLA2, an acidic non-toxic PLA2 from the same venom did not markedly synergize with Lys49 myotoxin, revealing a functional difference between basic and acidic PLA2 enzymes. It is suggested that Asp49 myotoxins synergize with Lys49 myotoxins by virtue of their PLA2 activity. In addition to the membrane-destabilizing effect of this activity, Asp49 myotoxins may generate anionic patches of hydrolytic reaction products, facilitating electrostatic interactions with Lys49 myotoxins. These data provide new evidence for the evolutionary adaptive value of the two subtypes of PLA2 myotoxins acting synergistically in viperid venoms.

Role of enzymatic activity in muscle damage and cytotoxicity induced by Bothrops asper Asp49 phospholipase A2 myotoxins: are there additional effector mechanisms involved?

Viperid venoms often contain mixtures of Asp49 and Lys49 PLA2 myotoxin isoforms, relevant to development of myonecrosis. Given their difference in catalytic activity, mechanistic studies on each type require highly purified samples. Studies on Asp49 PLA2s have shown that enzyme inactivation using p-bromophenacyl bromide (p-BPB) drastically affects toxicity. However, based on the variable levels of residual toxicity observed in some studies, it has been suggested that effector mechanisms independent of catalysis may additionally be involved in the toxicity of these enzymes, possibly resembling those of the enzymatically inactive Lys49 myotoxins. A possibility that Lys49 isoforms could be present in Asp49 PLA2 preparations exists and, if undetected in previous studies, could explain the variable residual toxicity. This question is here addressed by using an enzyme preparation ascertained to be free of Lys49 myotoxins. In agreement with previous reports, inactivation of the catalytic activity of an Asp49 myotoxin preparation led to major inhibition of toxic effects in vitro and in vivo. The very low residual levels of myotoxicity (7%) and cytotoxicity (4%) observed can be attributed to the low, although detectable, enzyme remaining active after p-BPB treatment (2.7%), and would be difficult to reconcile with the proposed existence of additional catalytic-independent toxic mechanisms. These findings favor the concept that the effector mechanism of toxicity of Asp49 PLA2 myotoxins from viperids fundamentally relies on their ability to hydrolyze phospholipids, arguing against the proposal that membrane disruption may also be caused by additional mechanisms that are independent of catalysis.

Proteomic and toxicological profiling of the venom of Bothrocophias campbelli, a pitviper species from Ecuador and Colombia.

Detailed snake venom proteomes for nearly a hundred species in different pitviper genera have accumulated using 'venomics' methodologies. However, venom composition for some lineages remains poorly known. Bothrocophias (toad-headed pitvipers) is a genus restricted to the northwestern portion of South America for which information on venom composition is lacking. Here, we describe the protein composition, toxicological profiling, and antivenom neutralization of the venom of Bothrocophias campbelli, a species distributed in Colombia and Ecuador. Our analyses show that its venom mainly consists of phospholipases A2 (43.1%), serine proteinases (21.3%), and metalloproteinases (15.8%). The low proportion of metalloproteinases and high amount of a Lys49 phospholipase A2 homologue correlate well with the low hemorrhagic and high myotoxic effects found. Overall, B. campbelli venom showed a simpler composition compared to other crotalines in the region. A polyvalent antivenom prepared with a mixture of Bothrops asper, Crotalus simus, and Lachesis stenophrys venoms cross-recognized B. campbelli venom and neutralized its lethal effect in mice, albeit with a lower potency than for B. asper venom. Additional work comparing B. campbelli venom properties with those of related species could help understand the evolution of different venom protein families during the South American radiation of New World pitvipers.

Two color morphs of the pelagic yellow-bellied sea snake, Pelamis platura, from different locations of Costa Rica: snake venomics, toxicity, and neutralization by antivenom.

The yellow-bellied sea snake, Pelamis platura, is the most broadly distributed snake species. Despite being endowed with a highly lethal venom, a proteomic analysis of its toxin composition was unavailable. The venoms of specimens collected in Golfo de Papagayo and Golfo Dulce (Costa Rica), where two distinctive color morphs occur, were chromatographically compared. The latter inhabits a fjord-like gulf where the transit of oceanic sea snakes into and from the basin is restricted, thus possibly affecting gene flow. RP-HPLC evidenced a conserved venom protein profile in both populations, despite their divergent color phenotypes. Following a trend observed in other sea snakes, P. platura venom is relatively simple, being composed of proteins of the three-finger toxin (3FTx), phospholipase A2 (PLA2), cysteine-rich secretory protein (CRISP), 5'-nucleotidase, and metalloproteinase families. The first three groups represent 49.9%, 32.9%, and 9.1% of total venom protein, respectively. The most abundant component (~26%) is pelamitoxin (P62388), a short-chain 3FTx, followed by a major basic PLA2 (~20%) and a group of three isoforms of CRISPs (~9%). Whereas isolated pelamitoxin was highly lethal to mice, neither the PLA2 nor the CRISP fraction caused death. However, the PLA2 rapidly increased plasma creatine kinase activity after intramuscular injection, indicating its myotoxic action. Differing from myotoxic PLA2s of viperids, this PLA2 was not cytolytic to murine myogenic cells in vitro, suggesting possible differences in its mechanism of action. The median lethal dose (LD50) estimates for P. platura crude venom in mice and in three species of fishes did not differ significantly. The sea snake antivenom manufactured by CSL Ltd. (Australia), which uses Enhydrina schistosa as immunogen, cross-recognized the three major components of P. platura venom and, accordingly, neutralized the lethal activity of crude venom and pelamitoxin, therefore being of potential usefulness in the treatment of envenomations by this species. BIOLOGICAL SIGNIFICANCE: Integrative analyses of animal venoms that combine the power of proteomics (venomics) with the characterization of their functional and immunological properties are significantly expanding knowledge on these remarkable bioweapons, both from a basic and a medical perspective. Costa Rica harbors a unique population of the yellow-bellied sea snake, Pelamis platura, that is restricted to a fjord-like gulf (Golfo Dulce). This population differs markedly from oceanic populations found elsewhere along the Pacific coast of this country, by presenting a patternless bright yellow coloration, instead of the typical bicolored or tricolored pattern of this species. It has been suggested that the dominance of this yellow-morph in Golfo Dulce might reflect gene flow restrictions, caused by the oceanographic conditions at this location. The present study demonstrates that the remarkable phenotypic variation between the two color morphs inhabiting Golfo Dulce and Golfo de Papagayo, respectively, is not associated with differences in the expression of venom components, as shown by their conserved RP-HPLC profiles. Proteomic analysis revealed the relatively simple toxin composition of P. platura venom, which contains three predominant types of proteins: three-finger toxins (protein abundance: 49.9%), phospholipases A2 (32.9%), and cysteine-rich secretory proteins (9.1%), together with few minor components. Further, the involvement of these most abundant proteins in the toxic effects of the venom, and their cross-recognition and neutralization by a sea snake antivenom produced against the venom of Enhydrina schistosa, were analyzed.

Venomics of New World pit vipers: genus-wide comparisons of venom proteomes across Agkistrodon.

We report a genus-wide comparison of venom proteome variation across New World pit vipers in the genus Agkistrodon. Despite the wide variety of habitats occupied by this genus and that all its taxa feed on diverse species of vertebrates and invertebrate prey, the venom proteomes of copperheads, cottonmouths, and cantils are remarkably similar, both in the type and relative abundance of their different toxin families. The venoms from all the eleven species and subspecies sampled showed relatively similar proteolytic and PLA2 activities. In contrast, quantitative differences were observed in hemorrhagic and myotoxic activities in mice. The highest myotoxic activity was observed with the venoms of A. b. bilineatus, followed by A. p. piscivorus, whereas the venoms of A. c. contortrix and A. p. leucostoma induced the lowest myotoxic activity. The venoms of Agkistrodon bilineatus subspecies showed the highest hemorrhagic activity and A. c. contortrix the lowest. Compositional and toxicological analyses agree with clinical observations of envenomations by Agkistrodon in the USA and Central America. A comparative analysis of Agkistrodon shows that venom divergence tracks phylogeny of this genus to a greater extent than in Sistrurus rattlesnakes, suggesting that the distinct natural histories of Agkistrodon and Sistrurus clades may have played a key role in molding the patterns of evolution of their venom protein genes. BIOLOGICAL SIGNIFICANCE: A deep understanding of the structural and functional profiles of venoms and of the principles governing the evolution of venomous systems is a goal of venomics. Isolated proteomics analyses have been conducted on venoms from many species of vipers and pit vipers. However, making sense of these large inventories of data requires the integration of this information across multiple species to identify evolutionary and ecological trends. Our genus-wide venomics study provides a comprehensive overview of the toxic arsenal across Agkistrodon and a ground for understanding the natural histories of, and clinical observations of envenomations by, species of this genus.

Proteomic and functional profiling of the venom of Bothrops ayerbei from Cauca, Colombia, reveals striking interspecific variation with Bothrops asper venom.

Bothrops ayerbei, a pitviper inhabiting the Patía River's basin (Valle Alto del Río Patía) in the Southwestern Department of Cauca, Colombia, was considered as a variant form of Bothrops asper prior to being proposed as a new species in 2010, on the basis of subtle morphological differences. This study reports the proteomic and functional profiling of B. ayerbei venom. Its most striking feature is an almost complete absence (0.7%) of phospholipases A2 (PLA2), which is in contrast to the high proportion of these enzymes (25.3%) in the venom of B. asper from Cauca, as well as in other species of Bothrops. The predominant proteins in B. ayerbei venom are metalloproteinases (53.7%), in agreement with its higher hemorrhagic and lethal activities compared to B. asper venom. Moreover, the negligible content of PLA2s in B. ayerbei venom correlates with its weaker myotoxic effect, in contrast to B. asper venom, here shown to contain abundant Asp49- and Lys49-type PLA2s responsible for its strong myotoxic activity. Other components identified in B. ayerbei venom include bradykinin-potentiating-like peptides and proteins belonging to the C-type lectin/lectin-like, serine proteinase, l-amino acid oxidase, disintegrin, cysteine-rich secretory protein, nerve growth factor, and phosphodiesterase families. The venom composition of B. ayerbei resembles that of neonate specimens of B. asper, which shows a predominance of metalloproteinases, with only low amounts of PLA2s. Therefore, the present findings suggest that the expression of venom proteins in B. ayerbei, in contrast to B. asper, might retain a marked 'paedomorphic' condition. Altogether, the proteomic and toxicological characterization of the venom of B. ayerbei here reported argues in favor of its taxonomical separation from B. asper in Cauca, Colombia. BIOLOGICAL SIGNIFICANCE: B. ayerbei, a pitviper found in Cauca, Colombia, had been considered as a variant form of B. asper, but was recently described as a new species on the basis of subtle morphological differences. Our study provides the first detailed proteomic and functional analysis of the venom of B. ayerbei, revealing striking interspecific variation from B. asper, thus arguing in favor of their taxonomical separation. In addition, the observed composition of the venom of B. ayerbei correlates well with its functional and toxicological properties, helping to predict the main clinical manifestations in envenomings by this species, which inflicts a considerable number of snakebites in the Southwestern regions of Colombia.