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

The treatment of cutaneous leishmaniasis (CL) is challenged by limited therapeutic options, high drug toxicity, and frequent treatment failure. In this context, iron oxide nanoparticles (IONPs) have emerged as promising therapeutic alternatives. This review summarizes experimental findings on the in vitro and in vivo anti-Leishmania activity of IONPs, highlighting their potential as a treatment for CL. A systematic search of PubMed, ScienceDirect, and Scopus identified 16 studies evaluating the anti-Leishmania effects of IONPs across various CL models. The studies assessed IONPs' physicochemical properties (size, shape, polydispersity index, and zeta potential), functionalization strategies, and efficacy against axenic and intracellular Leishmania forms, as well as in animal models. Most studies investigated spherical IONPs ranging from 5 to 90 nm, with polydispersity index values between 0.2 and 1.0 and zeta potentials from -13 mV to +35 mV. Functionalization improved dispersion and enabled antimicrobial conjugation. IONPs reduced axenic Leishmania viability, decreased intracellular parasitism, and lowered parasite loads in infected mouse lesions. In vitro, parasite death was linked to lysosomal rupture, oxidative stress, apoptosis, necrosis, and nitric oxide production by macrophages. In vivo, treated animals exhibited reduced parasite burdens, milder lesions, and enhanced IFN-γ production, suggesting improved immune responses. Despite these promising effects, issues such as formulation optimization, biocompatibility, and evaluation of pharmacokinetics and pharmacodynamics remain to be addressed. IONPs represent a novel and promising dual-action therapeutic strategy for CL, combining antiparasitic effects with immune modulation. However, important knowledge gaps persist regarding their mechanisms of action, long-term safety, efficacy across different Leishmania species and clinical scenarios. Further research is needed to advance IONPs as a safe and effective treatment for CL.

Background: Scorpion venom contains a variety of toxin molecules that are the drivers of inflammation and oxidative stress, leading to significant tissue damage. While several mechanisms underlying these responses have been studied, the involvement of the proteasome complex - a key regulator of inflammation - remains poorly understood. This study explored the role of the proteasome in modulating inflammatory and oxidative responses to envenomation by Androctonus australis hector venom.

Methods: Mice were pretreated intraperitoneally with bortezomib, a proteasome inhibitor, at low (0.05 mg/kg), medium (0.25 mg/kg), or high (0.5 mg/kg) doses, 30 minutes prior to sublethal venom administration (0.5 mg/kg, subcutaneous). Twenty-four hours after venom administration, animals were euthanized, blood and organs were collected to evaluate vascular permeability (via Evans blue dye extravasation), the extent of inflammatory cell infiltration (myeloperoxidase and eosinophil peroxidase enzymatic activities), and oxidative/nitrosative stress markers (nitric oxide, hydrogen peroxide_, malondialdehyde, catalase activity, and glutathione). Histopathological examinations were performed to identify structural alterations, such as edema, hemorrhage, and cellular infiltration. Biochemical parameters reflecting organ function, including serum levels of CPK, LDH, ALT, ALP, urea, and creatinine, were also measured to assess the degree of systemic damage.

Results: Our findings revealed a dose-dependent immune-modulatory role of the proteasome system. A medium dose of bortezomib reduced inflammatory and oxidative stress markers, such as vascular permeability, eosinophil peroxidase, neutrophil peroxidase, nitric oxide, and malondialdehyde in renal tissue, suggesting a reduction in local inflammation and oxidative damage. In contrast, a higher dose showed pronounced preventive effects in cardiopulmonary and hepatic tissues, significantly reducing inflammatory mediators and oxidative markers, restoring antioxidant enzyme activity (catalase) and glutathione, as well as, improving tissue structure and organ function.

Conclusion: These findings underscore the proteasome involvement in inflammatory regulation, likely through modulation of vascular permeability, immune cell activation, and oxidative stress, making it a key target in scorpion envenomation.

Background: Inflammation plays a critical role in the pathogenesis of limb injury caused by Deinagkistrodon acutus snakebite. Investigating its regulatory mechanisms and intervention strategies may help identify effective treatments. Recent studies have shown that pyroptosis exacerbates organ damage by amplifying inflammatory responses. Additionally, immune and matrix-regulatory cells (IMRC), a novel type of mesenchymal stem cell, and their exosomes (Exo) have demonstrated potential in mitigating inflammation-mediated injury by suppressing pyroptosis. This study aimed to evaluate whether IMRC-Exo could alleviate D. acutus venom-induced limb injury in rabbits by suppressing pyroptosis, thereby attenuating the associated inflammatory response.

Methods: Eighteen healthy male New Zealand white rabbits were randomly assigned to Sham, Model, and IMRC-Exo groups. The Model group was established by intramuscular injection of D. acutus venom (1.5 mg/kg), followed by intravenous snake antivenom (80 U/kg) after 2 hours. The IMRC-Exo group received IMRC-Exo (7.5 × 10¹⁰ particles) post-modeling. Within 24 hours, left thigh circumference, serum creatine kinase (CK), and myoglobin (Mb) were assessed. Muscle tissues were collected for histopathology, apoptosis analysis, inflammatory cytokine quantification [high-mobility group box 1 (HMGB1), IL-1β, IL-18], and pyroptosis-related protein detection [caspase-3, cleaved caspase-3, gasdermin E (GSDME), N-terminal GSDME (N-GSDME)].

Results: Compared to Sham, venom injection significantly increased thigh circumference, CK, Mb, histopathological damage, apoptosis, inflammatory cytokines, and pyroptosis-related proteins. IMRC-Exo significantly reduced these indicators, mitigating muscle injury and inflammation. Additionally, inflammatory cytokines and pyroptosis markers were significantly lower in the IMRC-Exo group than in the Model group.

Conclusion: IMRC-Exo effectively alleviates D. acutus venom-induced limb injury in rabbits, likely through inhibition of GSDME-dependent pyroptosis-mediated inflammation. These findings suggest that IMRC-Exo may serve as a promising therapeutic approach for snakebite-induced inflammatory injury.

Background: Acute kidney injury (AKI) is a serious complication associated with Daboia siamensis envenomation, primarily due to direct nephrotoxicity. This study aimed to investigate the effects of the phospholipase A₂ (RvPLA₂) fraction from D. siamensis venom on renal function and to assess whether pretreatment with ion channel blockers could mitigate these effects using an isolated perfused kidney (IPK) model.

Methods: Twenty IPKs were allocated into five groups (n = 4 each): (1) RvPLA₂ in calcium-deficient modified Krebs-Henseleit solution (MKHS), (2) RvPLA₂ in standard MKHS, (3) RvPLA₂ following pretreatment with verapamil (a voltage-gated Ca²⁺ channel blocker), (4) RvPLA₂ following pretreatment with amiloride (a Na⁺ channel blocker), and (5) RvPLA₂ following pretreatment with minoxidil (a KATP channel opener). Renal function parameters were assessed accordingly.

Results: Administration of 280 μg of RvPLA₂ in calcium-deficient MKHS caused no significant changes in renal function. In contrast, RvPLA₂ in standard MKHS (1.9 mM Ca²⁺) significantly increased perfusion pressure (PP), renal vascular resistance (RVR), and free water excretion (p < 0.05), while non-significant increases were observed in glomerular filtration rate (GFR), urinary flow rate (UF), osmolar clearance (C_osm), and the fractional excretion of sodium (FE_Na⁺) and potassium (FE_K⁺). Verapamil alone caused significant increases in GFR and C_osm (p < 0.05) and non-significant increases in PP, RVR, UF, FE_Na⁺, and free water excretion. Amiloride and minoxidil alone did not alter renal function. Pretreatment with verapamil, amiloride, or minoxidil failed to prevent the renal functional changes induced by RvPLA₂.

Conclusions: The RvPLA₂ activity requires Ca²⁺ for activation which may target distinct sites on the cell membrane, including ion channel receptors in nephrons. The effects of RvPLA₂ on glomerular and renal tubular function are independent and cannot be modified by pretreatment with different ion channel blockers.

Background: Snake venom C-type lectin-like proteins (also known as snaclecs) have anticoagulation and procoagulation effects by targeting platelet or coagulation factor IX/X, suggesting their potential as candidates for new anticoagulant drugs. Therefore, this study aims to evaluate the antiplatelet and antithrombotic effects of a new snaclec from Protobothrops mucrosquamatus venom and its potential as an anticoagulant candidate.

Methods: Promucetin was purified through sequential column chromatography, and its molecular mass was determined by SDS-PAGE. The α- and β-chains of promucetin were identified using liquid chromatography-mass spectrometry (LC-MS). In vitro analyses of platelet aggregation were performed using turbidimetric methods, thromboelastography, and coagulation activity assays. For in vivo experiments, promucetin was administered to rats at varying concentrations, and platelet changes were monitored. The antithrombotic effects of promucetin were assessed using a FeCl₃-induced rat thrombosis model.

Results: Promucetin existed as two multimers with molecular weights of 140.1 kDa and 91.9 kDa under non-reducing conditions. Sequence analysis revealed that its α-chain and β-chain shared 71% and 34% homology, respectively, with TMVA from the same snake venom. In vitro platelet aggregation assays indicated that promucetin activated platelets via glycoprotein Ib. Thromboelastography showed that promucetin inhibited both coagulation factor activity and platelet function, resulting in an anticoagulant effect. Specifically, thrombin time was prolonged, while activated partial thromboplastin time and prothrombin time remained unchanged. In vivo, promucetin administration led to a dose-dependent decrease in platelet count. At doses of 25 and 50 μg/kg, promucetin significantly inhibited thrombosis, with inhibition rates of 40.9% and 74.4%, respectively. For comparison, lysine acetylsalicylate produced an inhibition rate of 36.7%.

Conclusion: Promucetin exhibits significant ability to modulate coagulation function and effectively inhibit thrombosis by activating platelet via GPIb and reducing platelet count, which helps us understand its biological function in snake bites, it exhibits the potential to be a candidate for anticoagulant therapy.

Background: Cancer is one of the leading causes of death worldwide, with incidence rates continuously increasing, thereby posing a major healthcare challenge. Although many oncological drugs fulfill therapeutic requirements, they often show high toxicity due to their limited specificity. To address this problem, there has been a search for natural therapies, including animal venoms that harbor bioactive molecules with therapeutic potential, as well as biological models that facilitate their study. Consequently, three-dimensional culture models, such as spheroids, play a pivotal role in evaluating anticancer molecules, as they can effectively mimic in vivo tumor microenvironments.

Methods: This study aimed to establish the significance of spheroids in identifying venom-derived molecules as potential therapeutic alternatives against cancer, based on a systematic review conducted from 2010 to 2024. Following PRISMA guidelines, a systematic search was conducted in four databases using the terms "Spheroid" and "Venom". Of the 93 articles identified, 16 satisfied the inclusion criteria for this review.

Results: Notably, several bioactive molecules derived from snake, spider, scorpion, and bee venoms were evaluated using various spheroid formation methods. These molecules demonstrated cytotoxic effects that impaired spheroid formation and disrupted invasion and migration processes.

Conclusion: Overall, the findings indicate that the integration of three-dimensional culture models with venom-derived compounds constitutes a promising preclinical strategy for the development of innovative, venom-based therapeutic strategies for cancer treatment.

Background: In the biomedical field, translational science is the process of applying basic scientific knowledge to advance clinical research through the creation of new drugs, devices, medical procedures, preventive measures, and diagnostic kits. The Covid-19 pandemic exposed a shortage of professionals trained in translational research, essential for responding to global demands. To drive advancements, researchers must overcome the 'valley of death', a critical phase in clinical investigation. In response, CEVAP at São Paulo State University (UNESP), Botucatu, Brazil, has developed a strong 'knowledge industry' centered on Translational Science. As part of its research and innovation efforts, CEVAP has developed two biopharmaceuticals, the fibrin sealant and the apilic antivenom, which are currently in the final stage of development. In 2024, CEVAP began the first Brazilian Contract Development and Manufacturing Organization (CDMO) for developing and producing validated and qualified pilot-scale batches to generate clinical trial material.

Case presentation: The implementation of the optional undergraduate course in Translational Science marks a crucial step in strengthening the 'knowledge industry'. The program, developed in collaboration with São Paulo's three public universities (USP, UNESP, and UNICAMP), also involves an international partnership with the University of Oxford's Department of Pediatrics and the Oxford Research Group LATAM. The successful launch of this course underscores its importance in interdisciplinary education and institutional collaboration. By bridging gaps between research and application, the program equips professionals to meet the growing demand for expertise in translational science. Given the project's success, it will transition into a one-year 'Qualification in Translational Science', available to students enrolled in São Paulo state universities.

Conclusion: The preparation of these professionals will be strategic for transforming basic research into products for health, saving lives, and combating future pandemics that will emerge around the world.

Background: Brazilian waters are home to various venomous fish species, each with its unique venom composition. Although common, envenomation cases are largely underreported, leading to a lack of public health policies for prevention and treatment. Some of the most clinically relevant fish in Brazil include the stingray Potamotrygon orbignyi, the toadfish Thalassophryne nattereri, the scorpionfish Scorpaena plumieri, and the catfish Pseudoplatystoma fasciatum and Cathorops spixii.

Methods: We comprehensively searched reports about accidents involving venomous fish in Brazil and compared the toxic activities of some medically relevant species.

Results: From the biochemical and toxicological evaluation, we found that venoms show a hierarchy in the ability to induce local toxic effects in mice, probably related to the venom compound diversity with species-specific toxins. T. nattereri venom presents greater toxicity, causing more severe local responses than that of P. orbignyi, C. spixii, and P. fasciatum, which cause moderate reactions. The S. plumieri venom induced only a moderate level of edema and could not cause nociception or necrosis. These results highlight that envenomation by P. orbigny, C. spixii, and S. plumieri is marked by proteins with intense hemolytic/proteolytic and phospholipase activity. On the other hand, T. nattereri and P. fasciatum offered a broader panel of new toxin families.

Conclusion: Knowledge of fish venom biochemical and toxicological activities is crucial to antivenom therapy development and helps endorse the study of venomous fish and their impact on the public health system.

Background: Bufadienolides are the main secondary metabolites found in the paratoid gland secretions (PGS) of toads of the Bufonidae family. These compounds are considered the main bioactive components of PGS. The aim of this study was to develop and validate the first method for the quantification of total bufadienolides (free and esterified) in samples of paratoid secretions from toads, using the UV-Vis absorption spectrophotometry technique.

Methods: The proposed method was based on the bathochromic shift induced by the reaction of the α-pyrone group of bufadienolides (296 nm) with a 5% (w:v) aqueous solution of sodium hydroxide and detection at 356 nm, after 60 min (time defined based on the evaluation of kinetic assays).

Results: The proposed method showed wide linearity (r = 0.9999), low LOD (1.3 × 10^-4 µg/mL) and LOQ (3.9 × 10^-4 µg/mL), recovery (84%-99%), repeatability (%RSD ≤ 5), reproducibility and robustness (p > 0.05). The total bufadienolide content in PGS extracts from 12 samples of R. diptycha ranged from 478 to 801 mg of EqMB/g of extract, while the R. granulosa sample presented 661 mg of EqMB/g of extract.

Conclusion: The new developed method is innovative, simple, fast, accurate, robust, low cost, and can contribute to future research focused on the quantification of total bufadienolides in samples of toad glandular secretions. In addition to serving as a strategic tool in the selection of work matrices, optimizing time, and minimizing costs.

Background: Deinagkistrodon acutus, or the hundred-pace snake, poses severe health risks due to its venom. Envenomation by this snake leads to complications such as hemorrhage, edema, and coagulopathy. Traditional antivenoms are limited by venom variability and often contain non-neutralizing antibodies, highlighting the need for more precise and effective immunogens.

Methods: This study utilized epitope-based antibody technology to develop a targeted sera against venom metalloproteinases (MPs) and phospholipases A₂ (PLA₂s). Twelve antigenic epitopes were identified via bioinformatics, leading to the design of a composite antigen peptide, EpiMPLA. It was engineered to be expressed via two expression systems, resulting in the recombinant immunogens, ProMPLA and p2AMPLA.

Results: Immunization with ProMPLA and p2AMPLA produced robust antibody responses in mice, effectively inhibiting MPs and PLA₂s. In vitro assays demonstrated that sera from immunized mice reduced the activity of these venom enzymes, minimized venom-induced hemorrhage and edema, and restored blood coagulation. At a venom dose of 2×LD₅₀, all mice in the control group died, while survival rates were 90% for anti-ProMPLA and 70% for anti-p2AMPLA.

Conclusion: The EpiMPLA epitope represents a promising candidate for generating neutralizing antibodies against D. acutusvenom, demonstrating its potential to address critical gaps in current antivenom therapy. These findings not only validate the feasibility of epitope-based antivenom development but also pave the way for further research to optimize this strategy.