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

Background: Spider venoms are rich natural sources of bioactive chemicals ranging from low-molecular-mass compounds to larger molecules such as low molecular mass peptides, proteins, and enzymes. Some compounds have been reported to exhibit neuroactivity and show potential as therapeutic agents against neurological disorders. Thus, this study analyzed the neurobehavioral effects of selected venom fractions from Philippine tarantula species compared to FDA-approved drugs targeting neuroreceptors, ion channels, and enzymes.

Methods: The venom was collected from the tarantula by electrostimulation and fractionated by reverse-phase high-performance liquid chromatography (RP-HPLC). Nine of the eleven fractions were subjected to neurobehavioral analysis using zebrafish (Danio rerio) as the animal model. The fractions were administered intraperitoneally, and their neurobehavioral effects were examined using the novel tank test, fear response, social interaction, and mirror biting tests. Donepezil, lidocaine, and diazepam were used as positive controls, and normal saline solution (NSS) as the negative control of the study. The swimming patterns and trajectories of the zebrafish were monitored using idTracker and were graphed using GraphPad Prism v.9.0. Components of the most polar fraction were further analyzed by Ultra Performance Liquid Chromatography - Quadrupole Time of Flight Data Dependent Analysis to identify the components structurally.

Results: Preliminary screening of all the fractions revealed that Fraction 1 with 0.1 µg/µL exhibited donepezil-like behavior based on similar rapid-swimming movement from 0 to 31 time intervals, Fraction 4 with 0.1 µg/µL concentration exhibited diazepam-like behavior due to non-significant differences in its time spent on top of the tank ranging from20 to 40 minutes, and Fraction 8 with 0.1 µg/µL concentration exhibited lidocaine-like behavior based on both rapid swimming movement and time spent on top of the tank. Fractions 1, 4, and 8 were further evaluated by determining their dose-dependent response, which follows the effect of their corresponding positive control. Analysis of Fraction 1 resulted in the annotation of several non-peptidic components 4-OH-PhLac434 and its isomer using VenoMS and isopimaric acid, palmitamide, 9-octadecenamide, and 13-docosenamide as putative compounds present in this spider venom using GNPS.

Conclusion: Overall, the fractions of venom from the Orphnaecus tarantula species appear to induce distinct neurobehavioral effects, which may include hyperactivity, anxiolytic-like responses, and potential antinociceptive properties.

Background: Bothrops snakebite is common in the Amazon region and can lead to severe complications in the affected limb, including secondary bacterial infections, blisters, necrosis, and acute compartment syndrome (ACS) in extreme cases. Many of these patients reside in remote areas with limited resources, where early recognition of clinical indicators is decisive for the timely identification of ACS and subsequent decision-making by healthcare professionals. The aim of this study was to identify risk factors associated with ACS following Bothrops atrox envenomation in the Brazilian Amazon.

Methods: A case-control study was conducted in three health units of Manaus, Western Brazilian Amazon. The allocation ratio was 1:3, with cases defined as B. atrox-envenomed patients developing ACS, and a control group consisting of patients who did not develop ACS.

Results: A total of 37 ACS cases and 111 controls were included in the study. Living in rural areas [OR = 4.59 (95%CI = 1.51-20.0; p = 0.017)], bites in the lower limbs [OR = 7.6 (95%CI = 3.18-19.3; p < 0.001)], time to medical care of 7-12 hours [OR = 4.23 (95%CI = 1.63-11.1; p = 0.003)], blisters [OR = 3.24 (95%CI = 1.12-9.25; p = 0.027)], and secondary bacterial infection [OR = 15 (95%CI = 3.54-103; p < 0.001)] were associated with ACS. Mean values of creatine kinase were significantly higher in ACS patients on the first (p = 0.022) and second (p = 0.013) days of hospitalization.

Conclusion: This study presents, for the first time, the factors associated with ACS from B. atrox envenomation, providing a basis for early diagnosis and treatment, and enabling prompt medical intervention. This may reduce adverse events, promote faster recovery, and lower the rate of disability.

Cnidarian venom toxins have attracted increasing interest due to their remarkable molecular diversity and pharmacological potential. Omics technologies - such as genomics, transcriptomics, proteomics, and metabolomics - have facilitated the identification of toxin-encoding genes, providing key insights into their evolutionary trajectories and structure-function relationships, which are essential for understanding their mechanisms of action and therapeutic value. Nevertheless, the functional validation and production of complex toxins remain challenging, particularly for those requiring intricate folding or post-translational modifications. Recombinant expression has emerged as a strategic alternative to traditional purification methods, enabling controlled toxin production and the possibility of modifying their properties through genetic engineering. In parallel, advances in synthetic biology, such as cell-free protein synthesis systems, are creating new opportunities for toxin characterization, although their industrial scalability remains limited. Computational tools, including those based on artificial intelligence, are beginning to support the prioritization and functional analysis of toxins identified through omics approaches. This review provides an updated overview of the advances, limitations, and future perspectives in cnidarian toxin research, highlighting their promising role as a valuable source of bioactive compounds with therapeutic and biotechnological applications.

Background: The COVID-19 pandemic exposed vulnerabilities in traditional disease surveillance systems, particularly in data reporting and contact tracing. Telemedicine emerged as a promising approach to expand remote access to healthcare. This study aimed to evaluate a newly implemented telemedicine system designed to manage patients with COVID-19, reduce hospital overload, enable early case detection and isolation, ensure rapid response to clinical deterioration, simplify medical records, and provide ongoing patient support.

Methods: A prospective cohort study was conducted using the E-care telemedicine system to assist adult patients presenting with COVID-19 symptoms at a Brazilian university between June 2021 and June 2024.

Results: The E-care system delivered care to 6,129 patients, predominantly female, white university students. Physicians attended over 80% (4,903/6,129) of patients and prescribed medications to nearly 28% (1,411/5,041). Medical certificates for time off work were issued to 43% (2,635/6,129) of participants. COVID-19 tests were recommended for approximately 24% of patients, with a positivity rate above 81% among those who returned results. Only 66 patients (1.2%) required in-person care, and no COVID-19-related deaths were reported. Patient satisfaction was high, with 96% (5,584/6,129) expressing satisfaction or high satisfaction with the service.

Conclusions: This study provides robust evidence supporting the successful implementation of a telemedicine system for managing COVID-19 cases. The large number of users highlights an unmet demand for virtual healthcare. Telemedicine was rapidly adopted, achieved high patient satisfaction, and contributed to reducing hospital burden, promoting early detection, and minimizing in-person consultations. These findings reinforce the value of telemedicine as an essential tool for health systems and policymakers to strengthen care delivery beyond the pandemic.

Background: Paracoccidioidomycosis (PCM) is a systemic mycosis endemic to Latin America, with the acute/subacute form predominantly affecting children and young adults. Cases of cecal appendicitis caused by Paracoccidioides spp. have rarely been reported. This study aimed to describe the clinical manifestations and evolution of a case of cecal appendicitis due to PCM and to conduct a systematic literature review.

Case presentation: We present the case of a 20-year-old male with generalized lymphadenopathy who was diagnosed with PCM and treated with oral trimethoprim-sulfamethoxazole. After the initial improvement, the patient returned with clinical deterioration. The treatment was changed to liposomal amphotericin B. Six days later; the patient developed an acute abdomen and underwent exploratory laparotomy with appendectomy. Histopathological examination confirmed acute granulomatous appendicitis due to PCM, and the patient showed postoperative clinical improvement. A systematic review were conducted using Embase, Web of Science, Lilacs, Medline, LIEPCS, PubMed, SciELO, and Gray Literature databases. Of the ten identified articles included in the systematic review, most case reports with a low risk of bias were found in South American countries. Seven patients were confirmed appendicitis due to PCM through biopsy, whereas one had confirmed PCM at another site. Two patients were initially misdiagnosed with Crohn's. Most studies have reported favorable outcomes.

Conclusion: Appendicitis caused by PCM is rare, even in endemic countries. It has a benign course when properly treated with both clinical and surgical management. This should be considered in the differential diagnosis of acute abdomen with lymphadenopathy in endemic regions.

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.