Journal of Venomous Animals and Toxins Including Tropical Diseases最新文献

Elephantiasis, also known as lymphatic filariasis (LF), is a debilitating condition characterized by the thickening of the skin and muscles, primarily affecting the limbs, genitalia, and female breasts. Lymphatic filariasis is a major global health concern, affecting approximately 120 million people worldwide and having a significant impact on people's quality of life, mobility, and socio-economic status. Although LF is endemic in many parts of the world, including Africa, it is a neglected issue in Southern Africa, with little information available. According to the World Health Organisation, approximately 882.5 million people in 44 countries worldwide are at risk of contracting LF, making it the second most common vector-borne disease after malaria. The primary goal of this review was to assess the prevalence of elephantiasis in the Southern African Development Community (SADC) region. Lymphatic filariasis is endemic in four of the sixteen SADC countries, three countries have administered MDA to the population that required it and they are now under post-intervention surveillance, while LF is no longer a public health problem in Malawi. Global efforts to eliminate LF have been hampered by the non-availability of MDA in some SADC countries such as Angola, Mozambique, Zambia, and Zimbabwe. Despite the implementation of mass drug administration programs, a review of the literature reveals gaps in knowledge about LF prevalence cases in SADC countries. Each country faces unique challenges and successes in combating LF due to varying levels of available data and healthcare infrastructure. Some SADC countries continue to bear the burden of LF-related diseases, necessitating ongoing disease prevention and elimination efforts. This review emphasizes the importance of ongoing research, data collection, and novel policies to combat the spread of elephantiasis disease in the SADC region and beyond.

Glioblastoma (GB) is the most common type of malignant tumor of the central nervous system, responsible for significant morbidity and with a 5-year overall relative survival of only 6.8%. Without advances in treatment in the last twenty years, the standard of care continues to be maximum safe resection, Temozolomide (TMZ), and radiotherapy. Many new trials are ongoing, and despite showing increased progression-free survival, these trials did not improve overall survival. They did not consider the adverse effects of these therapies. Therefore, an increasing number of bioprospecting studies have used snake venom molecules to search for new strategies to attack GB selectively without producing side effects. The present review aims to describe GB characteristics and current and new approaches for treatment considering their side effects. Besides, we focused on the antitumoral activity of snake venom proteins from the Viperidae family against GB, exploring the potential for drug design based on in vitro and in vivo studies. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. In January 2024, a systematic search was performed in the PubMed, EMBASE, and Web of Science databases from January 2000 to December 2023. Search terms were selected based on the population/exposure/outcome (PEO) framework and combined using Boolean operators ("AND", "OR"). The search strategy used these terms: glioblastoma, glioma, high-grade glioma, WHO IV glioma, brain cancer, snake venom, Viperidae, and bioprospection. We identified 10 in vivo and in vitro studies with whole and isolated proteins from Viperidae venom that could have antitumor activity against glioblastoma. Studies in bioprospecting exploring the advantage of snake venom proteins against GB deserve to be investigated due to their high specificity, small size, inherent bioactivity, and few side effects to cross the blood-brain barrier (BBB) to reach the tumor microenvironment.

Background: Pathophysiological mechanisms of rheumatoid arthritis arise because of a proinflammatory environment, generated by the interaction of autoreactive lymphocytes and proinflammatory mediators. Current strategies to mitigate the progression of the disease produce adverse effects, so there is a need for new therapeutic strategies and molecular targets to treat this disease. In this context, evidence suggests that scorpion venoms could modulate the immune response and some important cellular mechanisms of pharmacological interest. To evaluate the immunomodulatory effect of the venom of Tityus sp. (a possible new species close to Tityus metuendus) peripheral blood mononuclear cells of women diagnosed with RA were compared to cells of a control group.

Methods: A case-control study was conducted with a sample of 10 women with a confirmed diagnosis of RA and controls matched by sex and age. The cytotoxicity of the venom was evaluated to find sublethal concentrations of the venom, and subsequently, their immunomodulatory capacity in terms of percentage of proliferation, cell activation, and cytokines production.

Results: the venom of Tityus sp. produced a decrease in the percentage of proliferation in the CD3⁺, CD3⁺CD4⁺, and CD3⁺CD8⁺ cell subpopulations of RA patients and healthy controls, at concentrations of 252 and 126 µg/mL. However, the venom did not induce significant differences in the percentage of cell activation markers. The venom caused a decrease in IL-10 at a concentration of 252 µg/mL compared to untreated cells from patients and controls. The remaining cytokines did not show significant differences.

Conclusion: the venom of Tityus sp. is a potential source of molecules with immunomodulatory ability in CD4 and CD8 T lymphocytes. This result directs venom characterization studies to identify pharmacological targets with immunomodulatory capacity in T lymphocytes to enhance research in the treatment of autoimmune disorders such as RA.

The effect of peptide toxins on voltage-gated ion channels can be reliably assessed using electrophysiological assays, such as the patch-clamp technique. However, much of the toxinological research done in Central and South America aims at purifying and characterizing biochemical properties of the toxins of vegetal or animal origin, lacking electrophysiological approaches. This may happen due to technical and infrastructure limitations or because researchers are unfamiliar with the techniques and cellular models that can be used to gain information about the effect of a molecule on ion channels. Given the potential interest of many research groups in the highly biodiverse region of Central and South America, we reviewed the most relevant conceptual and methodological developments required to implement the evaluation of the effect of peptide toxins on mammalian voltage-gated ion channels using patch-clamp. For that, we searched MEDLINE/PubMed and SciELO databases with different combinations of these descriptors: "electrophysiology", "patch-clamp techniques", "Ca²⁺ channels", "K⁺ channels", "cnidarian venoms", "cone snail venoms", "scorpion venoms", "spider venoms", "snake venoms", "cardiac myocytes", "dorsal root ganglia", and summarized the literature as a scoping review. First, we present the basics and recent advances in mammalian voltage-gated ion channel's structure and function and update the most important animal sources of channel-modulating toxins (e.g. cnidarian and cone snails, scorpions, spiders, and snakes), highlighting the properties of toxins electrophysiologically characterized in Central and South America. Finally, we describe the local experience in implementing the patch-clamp technique using two models of excitable cells, as well as the participation in characterizing new modulators of ion channels derived from the venom of a local spider, a toxins' source less studied with electrophysiological techniques. Fostering the implementation of electrophysiological methods in more laboratories in the region will strengthen our capabilities in many fields, such as toxinology, toxicology, pharmacology, natural products, biophysics, biomedicine, and bioengineering.

Background: Acid-sensing ion channel 1a (ASIC1a) plays a critical role in physiological and pathological processes. To further elucidate the biological functions of ASICs and their relationships with disease occurrence and development, it is advantageous to investigate and develop additional regulatory factors for ASICs.

Methods: In this study, cation exchange chromatography was used to separate seven chromatographic components from Naja naja atra venom. Capillary electrophoresis was employed to detect that Ⅶ peak component containing a main protein Ⅶ-2, which could bind to ASIC1a. The analgesic effects of Ⅶ-2 protein were determined using hot plate methods, and ASIC1a expression in spinal cord tissue from rats with inflammatory pain was detected using western blot.

Results: The purified Ⅶ-2 protein named Naja naja atra venom-Ⅶ-2 (NNAV-Ⅶ-2) was obtained by Sephadex G-50 gel filtration, which exhibited a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a molecular weight of 6.7 kD. Remarkably, the NNAV-Ⅶ-2 protein demonstrated a significant analgesic effect and downregulated ASIC1a expression in the spinal cord tissue of rats with inflammatory pain.

Conclusions: The analgesic mechanism of the NNAV-Ⅶ-2 protein may be associated with its binding to ASIC1a, consequently downregulating ASIC1a expression in neural tissues.

Background: Members of the genus Cupiennius Simon, 1891 are categorized as wandering spiders and are part of the family Trechaleidae. The genomics and proteomics of Cupiennius spiders from North America remain uncharacterized. The present study explores for the first time molecular data from the endemic species Cupiennius chiapanensis Medina, 2006, and also presents new data for Cupiennius salei (Keyserling, 1878), both collected in southern Mexico.

Methods: In total, 88 Cupiennius specimens were collected from southern Mexico and morphologically identified. DNA was extracted and the mitochondrial COI fragment was amplified. COI sequences were analyzed, and a phylogenetic tree was inferred for species from the Americas. Genetic diversity was analyzed using haplotype networks and gene distances. Venom was obtained from C. chiapanensis and C. salei by electrostimulation. The venom was separated by HPLC, visualized using SDS-PAGE, and quantified for use in toxicity bioassays in mice and insects.

Results: Analysis of COI sequences from C. chiapanensis showed 94% identity with C. salei, while C. salei exhibited 94-97% identity with sequences from Central and South American conspecifics. The venom from C. chiapanensis exhibited toxic activity against crickets. Venoms from C. chiapanensis and C. salei caused death in Anastrepha obliqua flies. Analysis of venom fractions from C. salei and C. chiapanensis revealed molecular masses of a similar size as some previously reported toxins and neurotoxic components. We determined the amino acid sequences of ChiaTx1 and ChiaTx2, toxins that are reported here for the first time and which showed toxicity against mice and insects.

Conclusion: Our work is the first to report COI-based DNA barcoding sequences from southern Mexican Cupiennius spiders. Compounds with toxic activity were identified in venom from both species.

Background: Loxoscelism refers to a set of clinical manifestations caused by the bite of spiders from the Loxosceles genus. The classic clinical symptoms are characterized by an intense inflammatory reaction at the bite site followed by local necrosis and can be classified as cutaneous loxoscelism. This cutaneous form presents difficult healing, and the proposed treatments are not specific or effective. This study aimed to evaluate the protective effect of mesenchymal stromal cells-derived secretome on dermonecrosis induced by Loxosceles intermedia spider venom in rabbits.

Methods: Sixteen rabbits were distributed into four groups (n = 4). Except for group 1 (G1), which received only PBS, the other three groups (G2, G3, and G4) were initially challenged with 10 μg of L. intermedia venom, diluted in 100 μL of NaCl 0.9%, by intradermic injection in the interscapular region. Thirty minutes after the challenge all groups were treated with secretome, except for group 2. Group 1 (G1-control group) received intradermal injection (ID) of 60 μg of secretome in 0.15 M PBS; Group 2 (G2) received 0.9% NaCl via ID; Group 3 (G3) received 60 μg of secretome, via ID and Group 4 (G4), received 60 μg of secretome by intravenous route. Rabbits were evaluated daily and after 15 days were euthanized, necropsied and skin samples around the necrotic lesions were collected for histological analysis.

Results: Rabbits of G1 did not present edema, erythema, hemorrhagic halo, or necrosis. In animals from G2, G3, and G4, edema appeared after 6h. However, minor edema was observed in the animals of G2 and G3. Hemorrhagic halo was observed in animals, six hours and three days after, on G2, G3, and G4. Macroscopically, in G4, only one animal out of four had a lesion that evolved into a dermonecrotic wound. No changes were observed in the skin of the animals of G1, by microscopic evaluation. All animals challenged with L. intermedia venom showed similar alterations, such as necrosis and heterophilic infiltration. However, animals from G4 showed fibroblast activation, early development of connective tissue, neovascularization, and tissue re-epithelialization, indicating a more prominent healing process.

Conclusion: These results suggest that secretome from mesenchymal stromal cells cultured in a xeno-free and human component-free culture media can be promising to treat dermonecrosis caused after Loxosceles spiders bite envenoming.

Background: Paracoccidioidomycosis (PCM) is a severe granulomatous disease. The hallmark of this mycosis is fibrin degradation and granuloma formation as a result of a wound-healing process in the context of excessive inflammation. Therefore, as the content of collagen can be assessed by the methodology described in this manuscript, we propose that the content of hydroxyproline (HYP) be employed as a new and efficient measurement of granulomatous lesions developed. To estimate the level of HYP the major byproduct of the degradation process, we hypothesized that this simple and efficient technique could serve as a marker of disease severity.

Methods: Five B10.A female mice were infected with P. brasiliensis and, after 15 days, the omentum was removed, subjected to histopathological analysis or processed (i.e. deproteinized and derivatized), and further analyzed on a reverse phase HPLC using a C-18 column. The omentum of five uninfected controls was also collected and similarly analyzed.

Results: Infected mice showed numerous, disseminated paracoccidioidomycotic lesions, as well as marked collagen deposits, as observed in histopathologic analysis, and high levels of HYP. Normal uninfected mice showed no granulomas, little or no deposits of collagen fibers, and very low levels of HYP, as evaluated by HPLC. Our results show that the disease intensity as evaluated number and the morphology of the granulomatous lesions were correlated to the HYP levels using small tissue samples from the omentum, the main target organ of P. brasiliensis.

Conclusions: Here we propose an alternative methodology to follow disease evolution and, to some extent, fungal load in experimental P. brasiliensis infection and suggest its usefulness to other diseases with pronounced fibrin degradation.

Background: Parkinson's disease (PD) is the second most prevalent neurodegenerative disease. There is no effective treatment for neurodegenerative diseases. Snake venoms are a cocktail of proteins and peptides with great therapeutic potential and might be useful in the treatment of neurodegenerative diseases. Crotapotin is the acid chain of crotoxin, the major component of Crotalus durissus collilineatus venom. PD is characterized by low levels of neurotrophins, and synaptic and axonal degeneration; therefore, neurotrophic compounds might delay the progression of PD. The neurotrophic potential of crotapotin has not been studied yet.

Methods: We evaluated the neurotrophic potential of crotapotin in untreated PC12 cells, by assessing the induction of neurite outgrowth. The activation of the NGF signaling pathway was investigated through pharmacological inhibition of its main modulators. Additionally, its neuroprotective and neurorestorative effects were evaluated by assessing neurite outgrowth and cell viability in PC12 cells treated with the dopaminergic neurotoxin MPP⁺ (1-methyl-4-phenylpyridinium), known to induce Parkinsonism in humans and animal models.

Results: Crotapotin induced neuritogenesis in PC12 cells through the NGF-signaling pathway, more specifically, by activating the NGF-selective receptor trkA, and the PI3K/Akt and the MAPK/ERK cascades, which are involved in neuronal survival and differentiation. In addition, crotapotin had no cytotoxic effect and protected PC12 cells against the inhibitory effects of MPP⁺ on cell viability and differentiation.

Conclusion: These findings show, for the first time, that crotapotin has neurotrophic/neuroprotective/neurorestorative potential and might be beneficial in Parkinson's disease. Additional studies are necessary to evaluate the toxicity of crotapotin in other cell models.

Background: In this experimental protocol, we evaluated the immediate and delayed repair of the buccal branch of the facial nerve (BBFN) with heterologous fibrin biopolymer (HFB) as a coaptation medium and the use of photobiomodulation (PBM), performing functional and histomorphometric analysis of the BBFN and perioral muscles.

Methods: Twenty-eight rats were divided into eight groups using the BBFN bilaterally (the left nerve was used for PBM), namely: G1 - control group, right BBFN (without injury); G2 - control group, left BBFN (without injury + PBM); G3 - Denervated right BBFN (neurotmesis); G4 - Denervated left BBFN (neurotmesis + PBM); G5 - Immediate repair of right BBFN (neurotmesis + HFB); G6 - Immediate repair of left BBFN (neurotmesis + HFB + PBM); G7 - Delayed repair of right BBFN (neurotmesis + HFB); G8 - Delayed repair of left BBFN (neurotmesis + HFB + PBM). Delayed repair occurred after two weeks of denervation. All animals were sacrificed after six weeks postoperatively.

Results: In the parameters of the BBFN, we observed inferior results in the groups with delayed repair, in relation to the groups with immediate repair, with a significant difference (p < 0.05) in the diameter of the nerve fiber, the axon, and the thickness of the myelin sheath of the group with immediate repair with PBM compared to the other experimental groups. In measuring the muscle fiber area, groups G7 (826.4 ± 69.90) and G8 (836.7 ± 96.44) were similar to G5 (882.8 ± 70.51). In the functional analysis, the G7 (4.10 ± 0.07) and G8 (4.12 ± 0.08) groups presented normal parameters.

Conclusion: We demonstrated that delayed repair of BBFN is possible with HFB, but with worse results compared to immediate repair, and that PBM has a positive influence on nerve regeneration results in immediate repair.