Resumo em Inglês:

Abstract The genus Conus includes over 900 species of marine invertebrates known as cone snails, whose venoms are among the most powerful described so far. This potency is mainly due to the concerted action of hundreds of small bioactive peptides named conopeptides, which target different ion channels and membrane receptors and thus interfere with crucial physiological processes. By swiftly harpooning and injecting their prey and predators with such deadly cocktails, the slow-moving cone snails guarantee their survival in the harsh, competitive marine environment. Each cone snail species produces a unique venom, as the mature sequences of conopeptides from the venoms of different species share very little identity. This biochemical diversity, added to the numerous species and conopeptides contained in their venoms, results in an immense biotechnological and therapeutic potential, still largely unexplored. That is especially true regarding the bioprospection of the venoms of cone snail species found off the Brazilian coast - a region widely known for its biodiversity. Of the 31 species described in this region so far, only four - Conus cancellatus, Conus regius, Conus villepinii, and Conus ermineus - have had their venoms partially characterized, and, although many bioactive molecules have been identified, only a few have been actually isolated and studied. In addition to providing an overview on all the cone snail species found off the Brazilian coast to date, this review compiles the information on the structural and pharmacological features of conopeptides and other molecules identified in the venoms of the four aforementioned species, paving the way for future studies.

Resumo em Inglês:

Abstract Several regions of the world frequently use the species Moringa oleifera Lam. (Moringaceae) in traditional medicine. This situation is even more common in African countries. Many literature reports point to the antimalarial potential of this species, indicating the efficacy of its chemical compounds against malaria-causing parasites of the genus Plasmodium. From this perspective, the present study reviews the ethnobotanical, pharmacological, toxicological, and phytochemical (flavonoids) evidence of M. oleifera, focusing on the treatment of malaria. Scientific articles were retrieved from Google Scholar, PubMed®, ScienceDirect®, and SciELO databases. Only articles published between 2002 and 2022 were selected. After applying the inclusion and exclusion criteria, this review used a total of 72 articles. These documents mention a large use of M. oleifera for the treatment of malaria in African and Asian countries. The leaves (63%) of this plant are the main parts used in the preparation of herbal medicines. The in vivo antimalarial activity of M. oleifera was confirmed through several studies using polar and nonpolar extracts, fractions obtained from the extracts, infusion, pellets, and oils obtained from this plant and tested in rodents infected by the following parasites of the genus Plasmodium: P. berghei, P. falciparum, P. yoelii, and P. chabaudi. Extracts obtained from M. oleifera showed no toxicity in preclinical tests. A total of 46 flavonoids were identified in the leaves and seeds of M. oleifera by different chromatography and mass spectrometry methods. Despite the scarcity of research on the antimalarial potential of compounds isolated from M. oleifera, the positive effects against malaria-causing parasites in previous studies are likely to correlate with the flavonoids that occur in this species.

Resumo em Inglês:

Abstract This overview aimed to describe the situation of healthcare access in sub-Saharan Africa, excluding South Africa, during the COVID-19 pandemic. A PubMed® search from March 31, 2020, to August 15, 2022, selected 116 articles. Healthcare access and consequences of COVID-19 were assessed based on comparisons with months before its onset or an identical season in previous years. A general reduction of healthcare delivery, associated with the decline of care quality, and closure of many specialty services were reported. The impact was heterogeneous in space and time, with an increase in urban areas at the beginning of the pandemic (March-June 2020). The return to normalcy was gradual from the 3rd quarter of 2020 until the end of 2021. The impact of COVID-19 on the health system and its use was attributed to (a) conjunctural factors resulting from government actions to mitigate the spread of the epidemic (containment, transportation restrictions, closures of businesses, and places of entertainment or worship); (b) structural factors related to the disruption of public and private facilities and institutions, in particular, the health system; and (c) individual factors linked to the increase in costs, impoverishment of the population, and fear of contamination or stigmatization, which discouraged patients from going to health centers. They have caused considerable socio-economic damage. Several studies emphasized some adaptability of the healthcare offer and resilience of the healthcare system, despite its unpreparedness, which explained a return to normal activities as early as 2022 while the COVID-19 epidemic persisted. There appears to be a strong disproportion between the moderate incidence and severity of COVID-19 in sub-Saharan Africa, and the dramatic impact on healthcare access. Several articles make recommendations for lowering the socioeconomic consequences of future epidemics to ensure better management of health issues.

Resumo em Inglês:

Abstract This synoptic review aims to bring some general information on fossil scorpions, namely those trapped in amber - fossilized resin - ranging from Lower Cretaceous through the Palaeocene and up to the Miocene. The question to be addressed is how the study of these fossils can be connected with possible present scorpionism problems. A precise knowledge of these ancient lineages provides information about the evolution of extant lineages, including the buthoids, which contain most known noxious species. Among the Arthropods found trapped in amber, scorpions are considered rare. A limited number of elements have been described from the Late Tertiary Dominican and Mexican amber, while the most ancient Tertiary amber from the Baltic region produced more consistent results in the last 30 years, primarily focusing on a single limited lineage. Contrarily, the Cretaceous amber from Myanmar, also called Burmite, has yielded and continues to yield a significant number of results represented by several distinct lineages, which attest to the considerable degree of diversity that existed in the Burmese amber-producing forests. As in my previous similar contributions to this journal, the content of this note is primarily addressed to non-specialists whose research embraces scorpions in various fields such as venom toxins and public health. An overview knowledge of at least some fossil lineages can eventually help to clarify why some extant elements associated with the buthoids represent dangerous species while others are not noxious.

Resumo em Inglês:

ABSTRACT Snake venom disintegrins are low molecular weight, non-enzymatic proteins rich in cysteine, present in the venom of snakes from the families Viperidae, Crotalidae, Atractaspididae, Elapidae, and Colubridae. This family of proteins originated in venom through the proteolytic processing of metalloproteinases (SVMPs), which, in turn, evolved from a gene encoding an A Disintegrin And Metalloprotease (ADAM) molecule. Disintegrins have a recognition motif for integrins in their structure, allowing interaction with these transmembrane adhesion receptors and preventing their binding to proteins in the extracellular matrix and other cells. This interaction gives disintegrins their wide range of biological functions, including inhibition of platelet aggregation and antitumor activity. As a result, many studies have been conducted in an attempt to use these natural compounds as a basis for developing therapies for the treatment of various diseases. Furthermore, the FDA has approved Tirofiban and Eptifibatide as antiplatelet compounds, and they are synthesized from the structure of echistatin and barbourin, respectively. In this review, we discuss some of the main functional and structural characteristics of this class of proteins and their potential for therapeutic use.

Resumo em Inglês:

Abstract Venomous animals and their venom have always been of human interest because, despite species differences, coevolution has made them capable of targeting key physiological components of our bodies. Respiratory failure from lung injury is one of the serious consequences of envenomation, and the underlying mechanisms are rarely discussed. This review aims to demonstrate how toxins affect the pulmonary system through various biological pathways. Herein, we propose the common underlying cellular mechanisms of toxin-induced lung injury: interference with normal cell function and integrity, disruption of normal vascular function, and provocation of excessive inflammation. Viperid snakebites are the leading cause of envenomation-induced lung injury, followed by other terrestrial venomous animals such as scorpions, spiders, and centipedes. Marine species, particularly jellyfish, can also inflict such injury. Common pulmonary manifestations include pulmonary edema, pulmonary hemorrhage, and exudative infiltration. Severe envenomation can result in acute respiratory distress syndrome. Pulmonary involvement suggests severe envenomation, thus recognizing these mechanisms and manifestations can aid physicians in providing appropriate treatment.

Resumo em Inglês:

Abstract Aflatoxins are toxic secondary metabolites that often contaminate food and animal feed, causing huge economic losses and serious health hazards. Aflatoxin contamination has become a major concern worldwide. Biological methods have been used to reduce aflatoxins in food and feed by inhibiting toxin production and detoxification. Among biological methods, lactic acid bacteria are of significant interest because of their safety, efficiency, and environmental friendliness. This study aimed to review the mechanisms by which lactic acid bacteria degrade aflatoxins and the factors that influence their degradation efficiency, including the action of the lactic acid bacteria themselves (cell wall adsorption) and the antifungal metabolites produced by the lactic acid bacteria. The current applications of lactic acid bacteria to food and feed were also reviewed. This comprehensive analysis provided insight into the binding mechanisms between lactic acid bacteria and aflatoxins, facilitating the practical applications of lactic acid bacteria to food and agriculture.

Resumo em Inglês:

Abstract Background: Echinometra lucunter is a sea urchin commonly found on America’s rocky shores. Its coelomic fluid contains molecules used for defense and biological processes, which may have therapeutic potential for the treatment of amyloid-based neurodegenerative diseases, such as Alzheimer's, that currently have few drug options available. Methods: In this study, we incubated E. lucunter coelomic fluid (ELCF) and fractions obtained by solid phase extraction in SH-SY5Y neuron-like cells to evaluate their effect on cell viability caused by the oligomerized amyloid peptide 42 (Aβ42o). Moreover, the Aβ42o was quantified after the incubation with ELCF fractions in the presence or not of cells, to evaluate if samples could cause amyloid peptide disaggregation. Antioxidant activity was determined in ELCF fractions, and cells were evaluated to check the oxidative stress after incubation with samples. The most relevant fraction was analyzed by mass spectrometry for identification of molecules. Results: ELCF and certain fractions could prevent and treat the reduction of cell viability caused by Aβ42o in SH-SY5Y neuron-like cells. We found that one fraction (El50) reduced the oligomerized Aβ42 and the oxidative stress caused by the amyloid peptide through its antioxidant molecules, which in turn reduced cell death. Mass spectrometry analysis revealed that El50 comprises small molecules containing flavonoid antioxidants, such as phenylpyridazine and dihydroquercetin, and two peptides. Conclusion: Our results suggest that sea urchin molecules may interact with Aβ42o and oxidative stress, preventing or treating neurotoxicity, which may be useful in treating dementia.

Resumo em Inglês:

Abstract Snakebite envenoming is a significant global health challenge, and for over a century, traditional plasma-derived antivenoms from hyperimmunized animals have been the primary treatment against this infliction. However, these antivenoms have several inherent limitations, including the risk of causing adverse reactions when administered to patients, batch-to-batch variation, and high production costs. To address these issues and improve treatment outcomes, the development of new types of antivenoms is crucial. During this development, key aspects such as improved clinical efficacy, enhanced safety profiles, and greater affordability should be in focus. To achieve these goals, modern biotechnological methods can be applied to the discovery and development of therapeutic agents that can neutralize medically important toxins from multiple snake species. This review highlights some of these agents, including monoclonal antibodies, nanobodies, and selected small molecules, that can achieve broad toxin neutralization, have favorable safety profiles, and can be produced on a large scale with standardized manufacturing processes. Considering the inherent strengths and limitations related to the pharmacokinetics of these different agents, a combination of them might be beneficial in the development of new types of antivenom products with improved therapeutic properties. While the implementation of new therapies requires time, it is foreseeable that the application of biotechnological advancements represents a promising trajectory toward the development of improved therapies for snakebite envenoming. As research and development continue to advance, these new products could emerge as the mainstay treatment in the future.

Resumo em Inglês:

Abstract Background: Bivalent freeze-dried neurotoxic (FN) antivenom has been the primary treatment since the 1980s for Taiwan cobra (Naja atra) envenomation in Taiwan. However, envenomation-related wound necrosis is a significant problem after cobra snakebites. In the present study, we analyzed the changes in serum venom concentration before and after antivenom administration to discover their clinical implications and the surgical treatment options for wound necrosis. Methods: The patients were divided into limb swelling and wound necrosis groups. The clinical outcome was that swelling started to subside 12 hours after antivenom treatment in the first group. Serum venom concentrations before and after using antivenoms were measured to assess the antivenom's ability to neutralize the circulating cobra venom. The venom levels in wound wet dressing gauzes, blister fluids, and debrided tissues were also investigated to determine their clinical significance. We also observed the evolutional changes of wound necrosis and chose a better wound debridement timing. Results: We prospectively enrolled 15 Taiwan cobra snakebite patients. Males accounted for most of this study population (n = 11, 73%). The wound necrosis group received more antivenom doses than the limb swelling group (4; IQR:2-6 vs 1; IQR:1-2, p = 0.05), and less records of serum venom concentrations changed before/after antivenom use (p = 0.0079). The necrotic wound site may release venom into circulation and cause more severe envenomation symptoms. Antivenom can efficiently diminish limb swelling in cobra bite patients. However, antivenom cannot reduce wound necrosis. Patients with early debridement of wound necrosis had a better limb outcome, while late or without debridement may have long-term hospital stay and distal limb morbidity. Conclusions: Antivenom can efficiently eliminate the circulating cobra venom in limb swelling patients without wound necrosis. Early debridement of the bite site wound and wet dressing management are suggestions for preventing extended tissue necrosis and hospital stay.

Resumo em Inglês:

Abstract Background: Propolis exhibits huge potential in the pharmaceutical industry. In the present study, its effects were investigated on dendritic cells (DCs) stimulated with a tumor antigen (MAGE-1) and retinoic acid (RA) and on T lymphocytes to observe a possible differential activation of T lymphocytes, driving preferentially to Th1 or Treg cells. Methods: Cell viability, lymphocyte proliferation, gene expression (T-bet and FoxP3), and cytokine production by DCs (TNF-α, IL-10, IL-6 and IL-1β) and lymphocytes (IFN-γ and TGF-β) were analyzed. Results: MAGE-1 and RA alone or in combination with propolis inhibited TNF-α production and induced a higher lymphoproliferation compared to control, while MAGE-1 + propolis induced IL-6 production. Propolis in combination with RA induced FoxP3 expression. MAGE-1 induced IFN-γ production while propolis inhibited it, returning to basal levels. RA inhibited TGF-β production, what was counteracted by propolis. Conclusion: Propolis affected immunological parameters inhibiting pro-inflammatory cytokines and favoring the regulatory profile, opening perspectives for the control of inflammatory conditions.

Resumo em Inglês:

Abstract Background: Serological evaluation performed by double agar gel immunodiffusion test (DID) is used for diagnosis, evaluation of severity, management of paracoccidioidomycosis patients, and development of new clinical studies. For these reasons, the Botucatu Medical School of UNESP maintains a serum bank at the Experimental Research Unit with patient clinical data. This study aimed to evaluate the influence of the freeze-thaw cycle and different blood matrices on the titration of circulating antibodies. Methods: The study included 207 patients with confirmed (etiology-demonstrated) or probable (serology-demonstrated) paracoccidioidomycosis, and DID was performed with culture filtrate from Paracoccidioides brasiliensis B339 as antigen. First experiment: the antibody levels were determined in serum samples from 160 patients with the chronic form and 20 with the acute/subacute form, stored at -80oC for more than six months. Second experiment: titers of 81 samples of serum and plasma with ethylenediaminetetraacetic acid (EDTA) or heparin, from 27 patients, were compared according to matrix and effect of storage at -20oC for up to six months. Differences of titers higher than one dilution were considered discordant. Results: First experiment: test and retest presented concordant results in serum stored for up to three years, and discordant titers in low incidence in storage for four to six years but high incidence when stored for more than six years, including conversion from reagent test to non-reagent retest. Second experiment: serum, plasma-EDTA and plasma-heparin samples showed concordant titers, presenting direct correlation, with no interference of storage for up to six months. Conclusions: Storage at -80oC for up to six years has no or little influence on the serum titers determined by DID, permitting its safe use in studies depending on this parameter. The concordant titrations in different blood matrices demonstrated that the plasma can be used for immunodiffusion test in paracoccidioidomycosis, with stability for at least six months after storage at -20oC.

Resumo em Inglês:

Abstract Background: Phonotimpus pennimani (Araneae, Phrurolithidae) is a small-sized (3-5 mm) spider endemic to the Tacaná volcano in Chiapas, Mexico, where it is found in soil litter of cloud forests and coffee plantations. Its venom composition has so far not been investigated, partly because it is not a species of medical significance. However, it does have an important impact on the arthropod populations of its natural habitat. Methods: Specimens were collected in Southeastern Mexico (Chiapas) and identified taxonomically by morphological characteristics. A partial sequence from the mitochondrial gene coxI was amplified. Sequencing on the Illumina platform of a transcriptome library constructed from 12 adult specimens revealed 25 toxin or toxin-like genes. Transcripts were validated (RT-qPCR) by assessing the differential expression of the toxin-like PpenTox1 transcript and normalising with housekeeping genes. Results: Analysis of the coxI-gene revealed a similarity to other species of the family Phrurolithidae. Transcriptome analysis also revealed similarity with venom components of species from the families Ctenidae, Lycosidae, and Sicariidae. Expression of the toxin-like PpenTox1 gene was different for each developmental stage (juvenile or adult) and also for both sexes (female or male). Additionally, a partial sequence was obtained for the toxin-like PpenTox1 from DNA. Conclusion: Data from the amplification of the mitochondrial coxI gene confirmed that P. pennimani belongs to the family Phrurolithidae. New genes and transcripts coding for venom components were identified.

Resumo em Inglês:

Abstract Background: Isoliquiritigenin (ISL) presents antitumor effects against melanoma cells. It is known that various circular RNAs (circRNAs) are involved in the development of melanoma. Therefore, the present study aims to investigate the molecular mechanisms of ISL and circ_0002860. Methods: Circ_0002860, microRNA-431-5p (miR-431-5p) and member RAS oncogene family (RAB9A) were detected through reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assay. Cell viability was examined via cell counting kit-8 assay. The proliferation ability was assessed using colony formation assay. Cell apoptosis and cell cycle were determined by flow cytometry. Transwell assay was used for detection of migration and invasion. Western blot was conducted for protein analysis. Target binding was confirmed via dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. In vivo research was performed through xenograft tumor assay. Results: Circ_0002860 was downregulated by ISL in melanoma cells. ISL-induced inhibitory effects on cell proliferation, cell cycle progression, migration and invasion were alleviated by circ_0002860 overexpression. MiR-431-5p was a target of circ_0002860. Circ_0002860 eliminated the ISL-induced tumor inhibition via sponging miR-431-5p in melanoma cells. Circ_0002860 elevated the RAB9A level by targeting miR-431-5p. The function of ISL was related to miR-431-5p/RAB9A axis in melanoma progression. Tumor growth was reduced by ISL in vivo through downregulating circ_0002860 to regulate miR-431-5p and RAB9A levels. Conclusion: The current data indicates that ISL suppressed cell malignant progression of melanoma via targeting the circ_0002860/miR-431-5p/RAB9A pathway.

Resumo em Inglês:

Abstract Background: Conotoxins exhibit great potential as neuropharmacology tools and therapeutic candidates due to their high affinity and specificity for ion channels, neurotransmitter receptors or transporters. The traditional methods to discover new conotoxins are peptide purification from the crude venom or gene amplification from the venom duct. Methods: In this study, a novel O1 superfamily conotoxin Tx6.7 was directly cloned from the genomic DNA of Conus textile using primers corresponding to the conserved intronic sequence and 3’ UTR elements. The mature peptide of Tx6.7 (DCHERWDWCPASLLGVIYCCEGLICFIAFCI) was synthesized by solid-phase chemical synthesis and confirmed by mass spectrometry. Results: Patch clamp experiments on rat DRG neurons showed that Tx6.7 inhibited peak calcium currents by 59.29 ± 2.34% and peak potassium currents by 22.33 ± 7.81%. In addition, patch clamp on the ion channel subtypes showed that 10 μM Tx6.7 inhibited 56.61 ± 3.20% of the hCaV1.2 currents, 24.67 ± 0.91% of the hCaV2.2 currents and 7.30 ± 3.38% of the hNaV1.8 currents. Tx6.7 had no significant toxicity to ND7/23 cells and increased the pain threshold from 0.5 to 4 hours in the mouse hot plate assay. Conclusion: Our results suggested that direct cloning of conotoxin sequences from the genomic DNA of cone snails would be an alternative approach to obtaining novel conotoxins. Tx6.7 could be used as a probe tool for ion channel research or a therapeutic candidate for novel drug development.

Resumo em Inglês:

Abstract Background: Twenty-minute whole blood clotting test (20WBCT) and Modified Lee and White (MLW) method are the most routinely employed bedside tests for detecting coagulopathic snake envenomation. Our study compared the diagnostic utility of MLW and 20WBCT for snakebite victims at a tertiary care hospital in Central Kerala, South India. Methods: This single-center study recruited 267 patients admitted with snake bites. 20WBCT and MLW were performed simultaneously at admission along with the measurement of Prothrombin Time (PT). The diagnostic utility of 20WBCT and MLW was determined by comparing the sensitivity (Sn), specificity (Sp), positive and negative predictive values, likelihood ratios, and accuracy at admission with an INR value > 1.4. Results: Out of 267 patients, 20 (7.5%) patients had VICC. Amongst those who had venom-induced consumption coagulopathy (VICC), MLW was prolonged for 17 patients, (Sn 85% 95% confidence interval [CI]: 61.1-96.0) whereas 20WBCT was abnormal for 11 patients (Sn 55%, 95% CI: 32.04-76.17). MLW and 20WBCT were falsely positive for the same patient (Sp 99.6%, 95% CI: 97.4-99.9%). Conclusion: MLW is more sensitive than 20WBCT to detect coagulopathy at the bedside amongst snakebite victims. However, further studies are necessary for standardizing bedside coagulation tests in snakebite cases.

Resumo em Inglês:

Abstract Background: Bungarus multicinctus is one of the most dangerous venomous snakes prone to cardiopulmonary damage with extremely high mortality. In our previous work, we found that glutamine (Gln) and glutamine synthetase (GS) in pig serum were significantly reduced after Bungarus multicinctus bite. In the present study, to explore whether there is a link between the pathogenesis of cardiopulmonary injury and Gln metabolic changes induced by Bungarus multicinctus venom. We investigated the effect of Gln supplementation on the lung and heart function after snakebite. Methods: We supplemented different concentrations of Gln to mice that were envenomated by Bungarus multicinctus to observe the biological behavior, survival rate, hematological and pathological changes. Gln was supplemented immediately or one hour after the venom injection, and then changes in Gln metabolism were analyzed. Subsequently, to further explore the protective mechanism of glutamine on tissue damage, we measured the expression of heat-shock protein70 (HSP70), NF-κB P65, P53/PUMA by western blotting and real-time polymerase in the lung and heart. Results: Gln supplementation delayed the envenoming symptoms, reduced mortality, and alleviated the histopathological changes in the heart and lung of mice bitten by Bungarus multicinctus. Additionally, Gln increased the activity of glutamine synthetase (GS), glutamate dehydrogenase (GDH) and glutaminase (GLS) in serum. It also balanced the transporter SLC7A11 expression in heart and lung tissues. Bungarus multicinctus venom induced the NF-κB nuclear translocation in the lung, while the HO-1 expression was suppressed. At the same time, venom activated the P53/PUMA signaling pathway and the BAX expression in the heart. Gln treatment reversed the above phenomenon and increased HSP70 expression. Conclusion: Gln alleviated the glutamine metabolism disorder and cardiopulmonary damage caused by Bungarus multicinctus venom. It may protect lungs and heart against venom by promoting the expression of HSP70, inhibiting the activation of NF-κB and P53/PUMA, thereby delaying the process of snake venom and reducing mortality. The present results indicate that Gln could be a potential treatment for Bungarus multicinctus bite.

Resumo em Inglês:

Abstract Background: The composition of the venom from solitary wasps is poorly known, although these animals are considered sources of bioactive substances. Until the present moment, there is only one proteomic characterization of the venom of wasps of the family Pompilidae and this is the first proteomic characterization for the genus Pepsis. Methods: To elucidate the components of Pepsis decorata venom, the present work sought to identify proteins using four different experimental conditions, namely: (A) crude venom; (B) reduced and alkylated venom; (C) trypsin-digested reduced and alkylated venom, and; (D) chymotrypsin-digested reduced and alkylated venom. Furthermore, three different mass spectrometers were used (Ion Trap-Time of Flight, Quadrupole-Time of Flight, and Linear Triple Quadruple). Results: Proteomics analysis revealed the existence of different enzymes related to the insect’s physiology in the venom composition. Besides toxins, angiotensin-converting enzyme (ACE), hyaluronidase, and Kunitz-type inhibitors were also identified. Conclusion: The data showed that the venom of Pepsis decorata is mostly composed of proteins involved in the metabolism of arthropods, as occurs in parasitic wasps, although some classical toxins were recorded, and among them, for the first time, ACE was found in the venom of solitary wasps. This integrative approach expanded the range of compounds identified in protein analyses, proving to be efficient in the proteomic characterization of little-known species. It is our understanding that the current work will provide a solid base for future studies dealing with other Hymenoptera venoms.

Resumo em Inglês:

Abstract Background: Diabetic kidney disease (DKD) is a serious microvascular complication of diabetes that affects both type 1 and type 2 diabetes patients at a high incidence rate. Naja Naja atra venom (NNAV) has been shown to have protective effects and improved renal function in diabetic rats. However, its mechanism of action is still unclear. This study aims to unravel the effectiveness and mechanisms of NNAV on DKD. Methods: We conducted in vitro experiments in which Human Kidney-2 (HK-2) cells were stimulated with high glucose, and exposed to varying concentrations of NNAV. Cell morphology, as well as α-SMA, TGF-β1, and E-cadherin levels, were analyzed using immunofluorescence and western blot. In vivo experiments involved a diabetic rat model, where varying concentrations of cobra α-neurotoxin (CTX) were administrated via gastric treatment. We observed and noted pathomorphological changes, measured biochemical and oxidative stress indices, and used western blot to assess podocin and nephrin levels. Results: High glucose levels can induce a decrease in E-cadherin expression and an increase in α-SMA and transforming growth factor-β1 (TGF-β1) expression in HK-2 cells. NNAV can inhibit the transdifferentiation of HK-2 cells to myofibroblast (MyoF) in a high glucose environment and reduce the expression of TGF-β1. Cobra α-neurotoxin (CTX) can reduce urine protein in diabetes model rats at an early stage, which is dose-independent and has a time application range. CTX can regulate the expression of nephrin and podocin. Conclusion: The present study indicates that CTX and NNAV attenuate STZ and high glucose-induced DKD. Its mechanisms of action are associated with inhibiting oxidative stress and TEMT. The study suggests that NNAV and CTX might be a potential therapeutic drug for treating DKD.

Resumo em Inglês:

Abstract Background: Domestic cats have been implicated as accidental hosts of Leishmania sp. However, in recent years, the recurrent description of new cases in endemic and nonendemic areas draw attention to the potential epidemiological role of cats as reservoir hosts. Although dogs are considered urban reservoirs, cats could act as a secondary natural reservoirs in these areas. Thus, feline leishmaniasis has become an emerging disease in several countries worldwide. Case presentation: This study aimed to describe the first case of feline leishmaniasis in a stray animal that presented lesions compatible with the disease in Belém, Pará, Brazil, an important urban area in eastern Amazon. Serological tests for Leishmania infantum (ELISA and IFA) were nonreactive, whereas histopathological examination indicated infectious dermatitis caused by Leishmania spp. or Toxoplasma gondii. Cytopathological study of lesion aspirate confirmed the presence of Leishmania sp. amastigotes within macrophages. Finally, molecular analyses revealed that the feline infection was caused by Leishmania (Leishmania) infantum chagasi. Conclusion: To the best of the authors’ knowledge, this study reports the first case of natural infection by Leishmania (Leishmania) infantum chagasi in a feline from eastern Amazon. These findings suggest domestic cats as potential secondary reservoir hosts of Leishmania spp. in Belém, which reinforces the importance of further epidemiological investigation of feline leishmaniasis, especially in urban areas with human cases.