Wild Brazilian yellow fever virus infection in Syrian hamsters (Mesocricetus auratus): Clinical and histopathological analyses.

The Yellow Fever virus (YFV) wild-type strains studied until now have little or no ability to evade the Syrian hamster interferon antiviral response. Thus, evaluating the susceptibility of this model to new YFV isolates is paramount to aid in the understanding of their viscerotropic phenotype. To this end, Syrian hamsters were inoculated intraperitoneally with two Brazilian wild-type YFV isolates originated from dying or dead howler monkeys obtained during outbreaks in the states of Rio Grande do Sul in 2008 (PR4408) and Rio de Janeiro in 2019 (RJ155). The results were compared with a YFV experimental vaccine strain (17DDexp). The main findings observed for animals infected with the PR4408 strain were progressive weight loss and persistent viremia (at least up to day seven post-infection), associated with viral RNA detection in the liver, and hepatic, splenic, and pancreatic histological alterations consistent with YF. The infection was eliminated seven days post-infection in animals inoculated with the RJ155 strain. No changes were observed for animals infected with 17DDexp virus. The findings indicate that both Brazilian isolates are able to infect Syrian hamsters, resulting in histopathological changes compatible with the YF pathology observed in humans. Furthermore, the PR4408 strain exhibited increased virulence in this mammalian model, despite causing a non-fatal infection.

Entamoeba histolytica-induced NETs are highly cytotoxic on hepatic and colonic cells due to serine proteases and myeloperoxidase activities.

During intestinal and liver invasion by the protozoan parasite Entamoeba histolytica, extensive tissue destruction linked to large neutrophil infiltrates is observed. It has been proposed that microbicidal components of neutrophils are responsible for the damage, however, the mechanism by which they are released and act in the extracellular space remains unknown. In previous studies, we have shown that E. histolytica trophozoites induce NET formation, leading to the release of neutrophil granule content into extruded DNA. In this work, we evaluate the possible participation of NETs in the development of amoeba-associated pathology and analyze the contribution of anti-microbial components of the associated granules. E. histolytica-induced NETs were isolated and their effect on the viability and integrity of HCT 116 colonic and Hep G2 liver cultures were evaluated. The results showed that simple incubation of cell monolayers with purified NETs for 24 h resulted in cell detachment and death in a dose-dependent manner. The effect was thermolabile and correlated with the amount of DNA and protein present in NETs. Pretreatment of NETs with specific inhibitors of some microbicidal components suggested that serine proteases, are mostly responsible for the damage caused by NETs on HCT 116 cells, while the MPO activity was the most related to Hep G2 cells damage. Our study also points to a very important role of DNA as a scaffold for the activity of these proteins. We show evidence of the development of NETs in amoebic liver abscesses in hamsters as a preamble to evaluate their participation in tissue damage. In conclusion, these studies demonstrate that amoebic-induced NETs have potent cytotoxic effects on target cells and, therefore, may be responsible for the intense damage associated with tissue invasion by this parasite.

Detached epithelial cell plugs from the upper respiratory tract favour distal lung injury in Golden Syrian hamsters (Mesocricetus auratus) when experimentally infected with the A.2 Brazilian SARS-CoV-2 strain.

BACKGROUND: The Golden Syrian hamster (Mesocricetus auratus), Ferrets (Mustela putorius furo), and macaques have been described as useful laboratory animals naturally susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. OBJECTIVES: To study the mechanism of lung injury, we describe the histopathological features of SARS-CoV-2 infection in Golden Syrian hamsters inoculated intranasally with the A.2 Brazilian strain. METHODS: Hamsters were intranasally inoculated with the A.2 variant and euthanised at 3-, 5-, 10- and 15-days post-inoculation. The physical examination and body weight were recorded daily. Neutralising antibodies and viral RNA load of the respiratory tract were assessed during necropsies. FINDINGS: The coronavirus disease 2019 (COVID-19) model presented body weight loss, high levels of respiratory viral RNA load, severe segmentary pneumonitis, and bronchial fistula besides lymphatic trapping and infiltration, like the human SARS-COV-2 pathogenesis. The presence of subepithelial lymphoeosinophilic infiltrate was highlighted in our results; it contributed to the detachment of SARS-CoV-2 nucleocapsid-positive epithelial cells resulting in the infectious cell plugs. MAIN CONCLUSIONS: The SARS-CoV-2 caused segmentary pneumonia and vascular damage. In our comprehension, the infectious cell plugs, as being aspirated from the upper respiratory tract into the terminal bronchial lumen, work as a "Trojan horse", thus contributing to the dissemination of the SARS-CoV-2 infection into specific regions of the deep lung parenchyma.

Toxicological Evaluation of Kaempferol and Linearolactone as Treatments for Amoebic Liver Abscess Development in Mesocricetus auratus.

Several studies with kaempferol (KP) and linearolactone (LL) have demonstrated their antiparasitic activity. However, the toxicity of these treatments is unknown. Therefore, this study aimed to evaluate the possible toxicological effects of intraperitoneal (i.p.) administration of KP or LL on the amoebic liver abscess model (ALA) in Mesocricetus auratus. An ALA was induced in male hamsters with 1.5 × 105Entamoeba histolytica (E. histolytica) trophozoites inoculated in the left hepatic lobe. The lesion evolved for 4 days, and then KP (5 mg/kg body weight/day) or LL (10 mg/kg body weight/day) was administered for 4 consecutive days. Then, magnetic resonance imaging (MRI), paraclinical analyses, and necropsy for histopathological evaluation were performed. There was similar ALA inhibition by KP (19.42%), LL (28.16%), and metronidazole, the antiamoebic control (20.87%) (p ≤ 0.05, analysis of variance [ANOVA]). There were hepatic and renal biochemical alterations in all treatment groups, mainly for KP (aspartate aminotransferase: 347.5 ± 37.5 U/L; blood urea nitrogen: 19.4 ± 1.9 g/dL; p ≤ 0.05, ANOVA). Lesions found in the organs were directly linked to the pathology. In conclusion, KP and LL decreased ALA development and exerted fewer toxicological effects compared with metronidazole. Therefore, both compounds exhibit therapeutic potential as an alternative treatment of amoebiasis caused by E. histolytica. However, additional clinical studies in different contexts are required to reaffirm this assertion.

Production of recombinant cytokines and polyclonal antibodies for analysis of cellular immune response in golden Syrian hamster.

BACKGROUND: The development of therapies and vaccines for various diseases often necessitates the analysis of cellular immunity. However, unlike other rodents, the limited availability of reagents for Syrian hamsters restricts immunological analysis, particularly in the determination of serum effector molecules such as cytokines. In this study, we aim to produce and characterize the cytokines IFN-γ, TGF-ß, IL-6, IL-10, and TNF-α from Syrian hamsters in recombinant form and to generate polyclonal antibodies against them in rats. METHODS AND RESULTS: Cytokine transcript sequences were cloned into expression vectors in E. coli. Recombinant proteins were produced, purified through affinity chromatography, and characterized by Western blot using an anti-6xHis monoclonal antibody. Rats were immunized with the recombinant proteins to generate polyclonal antibodies (pAbs). These pAbs were characterized by Western blot and titrated by indirect ELISA. The recombinant cytokines rTNF-α, rIL-10, rIFN-γ, rTGF-ß, and rIL-6 were produced and specifically recognized at their expected molecular weights of 22.3 kDa, 19.8 kDa, 18.9 kDa, 11.8 kDa, and 22.9 kDa. pAbs were produced and demonstrated the ability to specifically recognize their target proteins with titers of 409,600 (rIL-10), 204,800 (rTNF-α), 102,400 (rIL-10), 51,200 (rTGF-ß), and 25,600 (rIFN-É£). CONCLUSIONS: The reagents produced represent a starting point for developing immunoassays to detect hamster cytokines, facilitating the analysis of cellular immunity in this biomodel.

Exercise Training Reduces Inflammation and Fibrosis and Preserves Myocardial Function and Perfusion in a Model of Chronic Chagas Cardiomyopathy. / Treinamento Físico Reduz a Inflamação e a Fibrose e Preserva a Função e a Perfusão Miocárdica em um Modelo de Cardiomiopatia Chagásica Crônica.

BACKGROUND: Chronic Chagas cardiomyopathy (CCC) is caused by an inflammatory process induced by Trypanosoma cruzi, which leads to myocarditis with reactive and reparative fibrosis. CCC progresses with myocardial perfusion abnormalities and histopathological events that affect cardiorespiratory fitness (CRF). OBJECTIVES: We evaluated the effects of aerobic physical training (APT) on myocardial perfusion and on morphological and functional impairments related with inflammation and fibrosis in Syrian hamsters with CCC. As a secondary objective, we analyzed the cross-sectional areas of the skeletal muscle. METHODS: Hamsters with CCC and their respective controls were divided into four groups: CCC sedentary, CCC-APT, sedentary control and APT control. Seven months after infection, the animals underwent echocardiography, myocardial perfusion scintigraphy and cardiopulmonary exercise testing. Moderate-intensity APT was performed for fifty minutes, five times a week, for eight weeks. Subsequently, the animals were reassessed. Histopathological analysis was conducted after the above-mentioned procedures. The level of significance was set at 5% in all analyses (p<0.05). RESULTS: CCC sedentary animals presented worse myocardial perfusion defects (MPD) over time, reduced left ventricle ejection fraction (LVEF) and showed more inflammation and fibrosis when compared to other groups (mixed ANOVA analysis). Conversely, APT was able to mitigate the progression of MPD, ameliorate inflammation and fibrosis and improve CRF efficiency in CCC-APT animals. CONCLUSIONS: Our study demonstrated that APT ameliorated cardiac dysfunction, MPD, and reduced inflammation and fibrosis in CCC hamster models. Additionally, CCC-SED animals presented skeletal muscle atrophy while CCC-APT animals showed preserved skeletal muscle CSA. Understanding APT's effects on CCC's pathophysiological dimensions is crucial for future research and therapeutic interventions.

FUNDAMENTO: A Cardiomiopatia Chagásica Crônica (CCC) é causada por um processo inflamatório induzido pelo Trypanosoma cruzi, que leva à miocardite com fibrose reativa e reparativa. A CCC progride com alterações de perfusão miocárdica e eventos histopatológicos que afetam a Aptidão Cardiorrespiratória (ACR). OBJETIVOS: Avaliamos os efeitos do Treinamento Físico Aeróbico (TFA) na perfusão miocárdica e nos comprometimentos morfológicos e funcionais relacionados à inflamação e fibrose em hamsters sírios com CCC. Como objetivo secundário, analisamos as áreas de secção transversa do músculo esquelético. MÉTODOS: Hamsters com CCC e seus respectivos controles foram divididos em quatro grupos: CCC sedentário, CCC-TFA, controle sedentário e controle TFA. Sete meses após a infecção, os animais foram submetidos à ecocardiografia, à cintilografia de perfusão miocárdica e ao teste de esforço cardiopulmonar. TFA de intensidade moderada foi realizado durante cinquenta minutos, cinco vezes por semana, por oito semanas. Posteriormente, os animais foram reavaliados. A análise histopatológica foi realizada após os procedimentos acima mencionados. O nível de significância foi estabelecido em 5% em todas as análises (p<0,05). RESULTADOS: Animais com CCC sedentários apresentaram piores Defeitos de Perfusão Miocárdica (DPM) ao longo do tempo, Fração de Ejeção do Ventrículo Esquerdo (FEVE) reduzida, e apresentaram mais inflamação e fibrose quando comparados aos demais grupos (análise ANOVA mista). Por outro lado, o TFA foi capaz de mitigar a progressão do DPM, atenuar a inflamação e a fibrose e melhorar a eficiência da ACR em animais CCC-TFA. CONCLUSÃO: Nosso estudo demonstrou que o TFA melhorou a disfunção cardíaca, DPM e reduziu a inflamação e a fibrose em modelos de hamster com CCC. Além disso, os animais CCC-SED apresentaram atrofia do músculo esquelético, enquanto os animais CCC-TFA apresentaram a AST do músculo esquelético preservada. Compreender os efeitos da TFA nas dimensões fisiopatológicas da CCC é crucial para futuras pesquisas e intervenções terapêuticas.

Unveiling the Enigmatic nature of six neglected Amazonian Leishmania (Viannia) species using the hamster model: Virulence, Histopathology and prospection of LRV1.

American tegumentary leishmaniasis (ATL) is highly endemic in the Amazon basin and occurs in all South American countries, except Chile and Uruguay. Most Brazilian ATL cases are due to Leishmania (Viannia) braziliensis, however other neglected Amazonian species are being increasingly reported. They belong to the subgenus L. (Viannia) and information on suitable models to understand immunopathology are scarce. Here, we explored the use of the golden hamster Mesocricetus auratus and its macrophages as a model for L. (Viannia) species. We also studied the interaction of parasite glycoconjugates (LPGs and GIPLs) in murine macrophages. The following strains were used: L. (V.) braziliensis (MHOM/BR/2001/BA788), L. (V.) guyanensis (MHOM/BR/85/M9945), L. (V.) shawi (MHOM/BR/96/M15789), L. (V.) lindenbergi (MHOM/BR/98/M15733) and L. (V.) naiffi (MDAS/BR/79/M5533). In vivo infections were initiated by injecting parasites into the footpad and were followed up at 20- and 40-days PI. Parasites were mixed with salivary gland extract (SGE) from wild-captured Nyssomyia neivai prior to in vivo infections. Animals were euthanized for histopathological evaluation of the footpads, spleen, and liver. The parasite burden was evaluated in the skin and draining lymph nodes. In vitro infections used resident peritoneal macrophages and THP-1 monocytes infected with all species using a MOI (1:10). For biochemical studies, glycoconjugates (LPGs and GIPLs) were extracted, purified, and biochemically characterized using fluorophore-assisted carbohydrate electrophoresis (FACE). They were functionally evaluated after incubation with macrophages from C57BL/6 mice and knockouts (TLR2-/- and TLR4-/-) for nitric oxide (NO) and cytokine/chemokine production. All species, except L. (V.) guyanensis, failed to generate evident macroscopic lesions 40 days PI. The L. (V.) guyanensis lesions were swollen but did not ulcerate and microscopically were characterized by an intense inflammatory exudate. Despite the fact the other species did not produce visible skin lesions there was no or mild pro-inflammatory infiltration at the inoculation site and parasites survived in the hamster skin/lymph nodes and even visceralized. Although none of the species caused severe disease in the hamster, they differentially infected peritoneal macrophages in vitro. LPGs and GIPLs were able to differentially trigger NO and cytokine production via TLR2/TLR4 and TLR4, respectively. The presence of a sidechain in L. (V.) lainsoni LPG (type II) may be responsible for its higher proinflammatory activity. After Principal Component analyses using all phenotypic features, the clustering of L. (V.) lainsoni was separated from all the other L. (Viannia) species. We conclude that M. auratus was a suitable in vivo model for at least four dermotropic L. (Viannia) species. However, in vitro studies using peritoneal cells are a suitable alternative for understanding interactions of the six L. (Viannia) species used here. LRV1 presence was found in L. (V.) guyanensis and L. (V.) shawi with no apparent correlation with virulence in vitro and in vivo. Finally, parasite glycoconjugates were able to functionally trigger various innate immune responses in murine macrophages via TLRs consistent with their inflammatory profile in vivo.

Hepatic endotheliitis in Golden Syrian hamsters (Mesocricetus auratus) experimentally infected with SARS-CoV-2.

Hepatic injuries in COVID-19 are not yet fully understood and indirect pathways (without viral replication in the liver) have been associated with the activation of vascular mechanisms of liver injury in humans infected with SARS-CoV-2. Golden Syrian hamsters are an effective model for experimental reproduction of moderate and self-limiting lung disease during SARS-CoV-2 infection. As observed in humans, this experimental model reproduces lesions of bronchointerstitial pneumonia and pulmonary vascular lesions, including endotheliitis (attachment of lymphoid cells to the luminal surface of endothelium). Extrapulmonary vascular lesions are well documented in COVID-19, but such extrapulmonary vascular lesions have not yet been described in the Golden Syrian hamster model of SARS-CoV-2 infection. The study aimed to evaluate microscopic liver lesions in Golden Syrian hamsters experimentally infected with SARS-CoV-2. In total, 38 conventional Golden Syrian hamsters, divided into infected group (n=24) and mock-infected group (n=14), were euthanized at 2-, 3-, 4-, 5-, 7-, 14-, and 15-days post infection with SARS-CoV-2. Liver fragments were evaluated by histopathology and immunohistochemical detection of SARS-CoV-2 Spike S2 antigens. The frequencies of portal vein endotheliitis, lobular activity, hepatocellular degeneration, and lobular vascular changes were higher among SARS-CoV-2-infected animals. Spike S2 antigen was not detected in liver. The main results indicate that SARS-CoV-2 infection exacerbated vascular and inflammatory lesions in the liver of hamsters with pre-existing hepatitis of unknown origin. A potential application of this animal model in studies of the pathogenesis and evolution of liver lesions associated with SARS-CoV-2 infection still needs further evaluation.

Protective effects of Ruscus extract in combination with ascorbic acid and hesperidine methylchalcone on increased leukocyte-endothelial interaction and macromolecular permeability induced by ischemia reperfusion injury.

BACKGROUND: Despite the well-recognized effectiveness of Ruscus aculetus extract combined or not with ascorbic acid (AA) and hesperidine methyl chalcone (HMC) on ischemia reperfusion (I/R) injury protection, little is known about the contribution of each constituent for this effect. OBJECTIVE: To investigate the effects of AA and HMC combined or not with Ruscus extract on increased macromolecular permeability and leukocyte-endothelium interaction induced by I/R injury. METHODS: Hamsters were treated daily during two weeks with filtered water (placebo), AA (33, 100 and 300 mg/kg/day) and HMC (50, 150 and 450 mg/kg/day) combined or not with Ruscus extract (50, 150 and 450 mg/kg/day). On the day of experiment, the cheek pouch microcirculation underwent 30 min of ischemia, and the number of rolling and adherent leukocytes and leaky sites were evaluated before ischemia and during 45 min of reperfusion. RESULTS: Ruscus extract combined with AA and HMC (Ruscus extract mixture) significantly prevented post-ischemic increase in leukocyte rolling and adhesion and macromolecular permeability compared to placebo and these effects were more prominent than AA and HMC alone on leukocyte adhesion and macromolecular leakage. CONCLUSION: Ruscus extract mixture were more effective than its isolated constituents in protect the hamster cheek pouch microcirculation against I/R injury.

Rapid development and mass production of SARS-CoV-2 neutralizing chicken egg yolk antibodies with protective efficacy in hamsters.

Despite the record speed of developing vaccines and therapeutics against the SARS-CoV-2 virus, it is not a given that such success can be secured in future pandemics. In addition, COVID-19 vaccination and application of therapeutics remain low in developing countries. Rapid and low cost mass production of antiviral IgY antibodies could be an attractive alternative or complementary option for vaccine and therapeutic development. In this article, we rapidly produced SARS-CoV-2 antigens, immunized hens and purified IgY antibodies in 2 months after the SARS-CoV-2 gene sequence became public. We further demonstrated that the IgY antibodies competitively block RBD binding to ACE2, neutralize authentic SARS-CoV-2 virus and effectively protect hamsters from SARS-CoV-2 challenge by preventing weight loss and lung pathology, representing the first comprehensive study with IgY antibodies. The process of mass production can be easily implemented in most developing countries and hence could become a new vital option in our toolbox for combating viral pandemics. This study could stimulate further studies, optimization and potential applications of IgY antibodies as therapeutics and prophylactics for human and animals.

Piperine, quercetin, and curcumin identified as promising natural products for topical treatment of cutaneous leishmaniasis.

Leishmania braziliensis (L. braziliensis) causes cutaneous leishmaniasis (CL) in the New World. The costs and the side effects of current treatments render imperative the development of new therapies that are affordable and easy to administer. Topical treatment would be the ideal option for the treatment of CL. This underscores the urgent need for affordable and effective treatments, with natural compounds being explored as potential solutions. The alkaloid piperine (PIP), the polyphenol curcumin (CUR), and the flavonoid quercetin (QUE), known for their diverse biological properties, are promising candidates to address these parasitic diseases. Initially, the in vitro cytotoxicity activity of the compounds was evaluated using U-937 cells, followed by the assessment of the leishmanicidal activity of these compounds against amastigotes of L. braziliensis. Subsequently, a golden hamster model with stationary-phase L. braziliensis promastigote infections was employed. Once the ulcer appeared, hamsters were treated with QUE, PIP, or CUR formulations and compared to the control group treated with meglumine antimoniate administered intralesionally. We observed that the three organic compounds showed high in vitro leishmanicidal activity with effective concentrations of less than 50 mM, with PIP having the highest activity at a concentration of 8 mM. None of the compounds showed cytotoxic activity for U937 macrophages with values between 500 and 700 mM. In vivo, topical treatment with QUE daily for 15 days produced cured in 100% of hamsters while the effectiveness of CUR and PIP was 83% and 67%, respectively. No failures were observed with QUE. Collectively, our data suggest that topical formulations mainly for QUE but also for CUR and PIP could be a promising topical treatment for CL. Not only the ease of obtaining or synthesizing the organic compounds evaluated in this work but also their commercial availability eliminates one of the most important barriers or bottlenecks in drug development, thus facilitating the roadmap for the development of a topical drug for the management of CL caused by L. braziliensis.

Optimization and comparative analysis of LAMP and PCR techniques for the detection of leptospiral DNA in Golden Syrian hamsters.

Leptospirosis is a zoonotic disease with significant public health and economic impact worldwide. Rapid and accurate diagnosis is essential for effective prevention and treatment. This study optimized a loop-mediated isothermal amplification (LAMP) assay using BFo isothermal DNA polymerase with different colorimetric indicators. LAMP was able to detect DNA from pathogenic and intermediate leptospires, while non-pathogenic leptospires and other non-leptospiral microorganisms were negative. LAMP assay combined with calcein showed a tenfold higher limit of detection (1 ng of leptospiral DNA per reaction) than LAMP combined with hydroxynaphthol blue or end-point PCR lipL32 (10 ng of DNA per reaction). Animal samples were collected from infected and non-infected Golden Syrian hamsters (Mesocricetus auratus) to evaluate and compare the performance of LAMP and PCR. These techniques showed a substantial agreement according to Cohen's kappa statistic, being both useful techniques for detecting leptospiral DNA in clinical samples. Overall, this study demonstrates that the LAMP assay is a sensitive, specific, rapid, and simple tool for the detection of leptospiral DNA. It has the potential to facilitate the diagnosis of leptospirosis, particularly in low-income regions with limited diagnosis resources.

Anti-Leishmania compounds can be screened using Leishmania spp. expressing red fluorescence (tdTomato).

The main challenges associated with leishmaniasis chemotherapy are drug toxicity, the possible emergence of resistant parasites, and a limited choice of therapeutic agents. Therefore, new drugs and assays to screen and detect novel active compounds against leishmaniasis are urgently needed. We thus validated Leishmania braziliensis (Lb) and Leishmania infantum (Li) that constitutively express the tandem tomato red fluorescent protein (tdTomato) as a model for large-scale screens of anti-Leishmania compounds. Confocal microscopy of Lb and Li::tdTomato revealed red fluorescence distributed throughout the entire parasite, including the flagellum, and flow cytometry confirmed that the parasites emitted intense fluorescence. We evaluated the infectivity of cloned promastigotes and amastigotes constitutively expressing tdTomato, their growth profiles in THP-1 macrophages, and susceptibility to trivalent antimony, amphotericin, and miltefosine in vitro. The phenotypes of mutant and wild-type parasites were similar, indicating that the constitutive expression of tdTomato did not interfere with the evaluated parameters. We applied our validated model to a repositioning strategy and assessed the susceptibility of the parasites to eight commercially available drugs. We also screened 32 natural plant and fungal extracts and 10 pure substances to reveal new active compounds. The infectivity and Glucantime treatment efficacy of BALB/c mice and golden hamsters infected with Lb and Li::tdTomato mutant lines, respectively, were very similar compared to animals infected with wild-type parasites. Standardizing our methodology would offer more rapid, less expensive, and easier assays to screen of compounds against L. braziliensis and L. infantum in vitro and in vivo. Our method could also enhance the discovery of active compounds for treating leishmaniasis.

Temporal Evaluation of the Surface Area of Treated Skin Ulcers Caused by Cutaneous Leishmaniasis and Relation with Optical Parameters in an Animal Model: A Proof of Concept.

Cutaneous leishmaniasis (CL) is a neglected disease caused by an intracellular parasite of the Leishmania genus. CL lacks tools that allow its understanding and treatment follow-up. This article presents the use of metrical and optical tools for the analysis of the temporal evolution of treated skin ulcers caused by CL in an animal model. Leishmania braziliensis and L. panamensis were experimentally inoculated in golden hamsters, which were treated with experimental and commercial drugs. The temporal evolution was monitored by means of ulcers' surface areas, as well as absorption and scattering optical parameters. Ulcers' surface areas were obtained via photogrammetry, which is a procedure that allowed for 3D modeling of the ulcer using specialized software. Optical parameters were obtained from a spectroscopy study, representing the cutaneous tissue's biological components. A one-way ANOVA analysis was conducted to identify relationships between both the ulcers' areas and optical parameters. As a result, ulcers' surface areas were found to be related to the following optical parameters: epidermis thickness, collagen, keratinocytes, volume-fraction of blood, and oxygen saturation. This study is a proof of concept that shows that optical parameters could be associated with metrical ones, giving a more reliable concept during the assessment of a skin ulcer's healing.

Andes Virus Genome Mutations That Are Likely Associated with Animal Model Attenuation and Human Person-to-Person Transmission.

We performed whole-genome sequencing with bait enrichment techniques to analyze Andes virus (ANDV), a cause of human hantavirus pulmonary syndrome. We used cryopreserved lung tissues from a naturally infected long-tailed colilargo, including early, intermediate, and late cell culture, passages of an ANDV isolate from that animal, and lung tissues from golden hamsters experimentally exposed to that ANDV isolate. The resulting complete genome sequences were subjected to detailed comparative genomic analysis against American orthohantaviruses. We identified four amino acid substitutions related to cell culture adaptation that resulted in attenuation of ANDV in the typically lethal golden hamster animal model of hantavirus pulmonary syndrome. Changes in the ANDV nucleocapsid protein, glycoprotein, and small nonstructural protein open reading frames correlated with mutations typical for ANDV strains associated with increased virulence in the small-animal model. Finally, we identified three amino acid substitutions, two in the small nonstructural protein and one in the glycoprotein, that were only present in the clade of viruses associated with efficient person-to-person transmission. Our results indicate that there are single-nucleotide polymorphisms that could be used to predict strain-specific ANDV virulence and/or transmissibility. IMPORTANCE Several orthohantaviruses cause the zoonotic disease hantavirus pulmonary syndrome (HPS) in the Americas. Among them, HPS caused by Andes virus (ANDV) is of great public health concern because it is associated with the highest case fatality rate (up to 50%). ANDV is also the only orthohantavirus associated with relatively robust evidence of person-to-person transmission. This work reveals nucleotide changes in the ANDV genome that are associated with virulence attenuation in an animal model and increased transmissibility in humans. These findings may pave the way to early severity predictions in future ANDV-caused HPS outbreaks.

Thymic alterations resulting from experimental visceral leishmaniasis in a Syrian hamster (Mesocricetus auratus).

BACKGROUND: The thymus is a lymphoid organ responsible for the development and maturation of T cells, which are part of the Th1, Th2, Th17, and Treg immune responses triggered by visceral leishmaniasis. The maturation and immunological development of T lymphocytes require a bidirectional interaction between the thymic microenvironment of epithelial cells, dendritic cells, and macrophages and the extracellular matrix with differentiating lymphocytes. OBJECTIVES: We evaluated the morphological characteristics and tissue distribution of hematopoietic and stromal cells in the thymuses of hamsters experimentally infected with Leishmania infantum, aiming to gain an insight into the pathophysiology of the disease. METHODS: Fifteen hamsters were subjected to intraperitoneal experimental infection with 107L. infantum promastigotes (MHOM/BR/1972/BH46). The animals were divided into three groups, each comprising five infected hamsters, and were then euthanized 15, 60, and 120 days postinfection. The control groups consisted of three groups of five healthy hamsters euthanized simultaneously with the infected ones. Thymic morphology was evaluated through histopathology and the cell composition through immunohistochemistry. We used antibodies to mark mesenchymal cells (anti-vimentin), epithelial cells (anti-cytokeratin), macrophages (anti-MAC387), B lymphocytes (anti-CD79a), and T lymphocytes (anti-CD3). Immunohistochemistry was also used to mark the parasite in the thymus. RESULTS: Infected and control hamsters showed no difference in thymic morphology and degree of atrophy. After 15 days of infection, CD3 + T lymphocytes in the thymus showed an increase that stabilized over time. At 120 days of infection, we detected a significant decrease in CD79a+ B lymphocytes. The parasite was present in the medullary and corticomedullary regions of 9 out of 15 hamsters. These findings confirm that the presence of a parasite can cause changes in a thymus cell population. However, further studies are needed to evaluate these changes' effects on the immune response of infected animals.

The chromatographic constitution of andiroba oil and his healing effects, compared to the LLLT outcomes, in oral mucositis induced in golden Syrian hamsters: a new treatment option.

The oral mucositis is a mucosal alteration that usually arises from oncological treatments, such as chemotherapy, and it is characterized as an inflammatory process. The aim of this study is to demonstrate the chromatographic constitution of Andiroba oil, comparing and evaluating Andiroba oil and laser scarring efficiency in treatments of oral mucositis in hamsters. These animals were submitted to 5-Fluorouracil. A total of 122 animals were used, randomized and divided into the following groups: (a) positive control; (b) laser associated to andiroba oil; (c) laser; (d) andiroba oil; (e) negative control; (f) cyclophosphamide (genotoxicity control). The induction of oral mucositis occurred by the administration of intraperitoneal Fluorouracila (60 mg/kg) and trauma to the mucosa. The laser protocol was performed once a day and the andiroba oil applied 3 times a day (1,5 ml/day). The mucosae were photographed and removed for clinical and histopathological analysis on day 4, 8, 12 and 15. The analysis was based in OM severity, in specific scoring for the clinical and histopathological aspect. Toxicity was evaluated on day 15 using comet assay and it was performed by variant DNA damage parameters. The data were analysed using analysis of variance (ANOVA) Tukey post-test and Kruskal-Wallis Dunn post-test. The "andiroba oil" and "laser" groups presented better results when compared to the control groups and the treatment associations. The andiroba oil presented the best scarring results, even considering its efficiency proximity to the laser treatment. Andiroba and laser, separately, did not present genotoxicity, however their association evidences damage to DNA.

Use of ozonized sunflower oil in the treatment of skin injury in golden hamster (Mesocricetus auratus): case report / Uso de óleo de girassol ozonizado no tratamento de lesão cutânea em hamster sírio (Mesocricetus auratus): relato de caso

Hamster breeding is becoming increasingly popular, mainly because of the simplicity of breeding, low cost, and characteristics of these animals: they are small, quiet, and do not require a large space. Because of this ease of keeping, some people choose to keep more than one animal of the same species in a single enclosure. In some cases, this sociability can lead to fights, because hamsters are extremely territorial animals, which can cause significant injuries. Knowledge of the most efficient methods for wound healing is essential in medicine for wild and exotic animals, as it allows faster clinical treatment and thus, stress reduction. The present case report refers to the therapeutic treatment of an extensive skin lesion in a golden hamster (Mesocricetus auratus) using ozonized sunflower oil. The treatment, which lasted 23 days, allowed complete healing of the lesion.

A criação de hamsters tem se tornado cada vez mais popular, especialmente pela facilidade de criação, pelo baixo custo e pelas características desses animais: são pequenos, silenciosos, e não necessitam de um grande espaço. Por essa facilidade de manejo, algumas pessoas decidem manter mais de um animal da mesma espécie em um único recinto. Em alguns casos, esse convívio pode causar brigas, visto que hamsters são animais extremamente territorialistas, podendo resultar em injúrias cutâneas significativas. O conhecimento sobre os métodos mais eficientes para a cicatrização de lesões é fundamental na medicina de animais silvestres e exóticos, possibilitando um manejo clínico mais rápido, consequentemente, redução do estresse. O presente relato refere-se ao manejo terapêutico de uma extensa lesão cutânea em um hamster sírio (Mesocricetus auratus) com o uso do óleo de girassol ozonizado. O tratamento, que teve 23 dias de duração, possibilitou a cicatrização total da lesão.

Effects of different routes of administration and doses of Sulodexide on leukocyte-endothelium interaction and tissue perfusion on an animal model of low flow and high pressure in veins.

OBJECTIVES: To assess the effects of different doses and routes of Sulodexide on leukocyte-endothelium interaction and tissue perfusion in a model of venous hypertension and low blood flow. METHODS: Six weeks after venous hypertension induction, through external iliac vein ligature male hamsters (Mesocricetus auratus) received Sulodexide at 1, 2, or 4 mg/kg/day or saline (placebo) by subcutaneous or intramuscular routes during 2 or 4 weeks. After treatments, leukocyte rolling and adhesion, functional capillary density (FCD), and venular diameter were evaluated on the affected hindlimb. RESULTS: Subcutaneous and intramuscular treatments with Sulodexide after 2 and 4 weeks, significantly reduced leukocyte rolling and adhesion and increased FCD. Sulodexide did not affect venular diameter and intramuscular treatment was more effective in reducing leukocyte adhesion than the subcutaneous one. CONCLUSION: This preliminary study demonstrated that Sulodexide significantly decreased leukocyte-endothelium interaction and improved tissue perfusion in hamsters subjected to venous hypertension and low blood flow.

Different inoculum of Leishmania braziliensis concentrations influence immunopathogenesis and clinical evolution in the ear dermis hamster model of cutaneous leishmaniasis.

The golden hamster (Mesocricetus auratus) is commonly used as a promising model for Leishmania braziliensis infection developing skin-ulcerated lesions. However, different protocols using high concentration of parasites inoculated in the footpad result in severe clinical disease. Here, we further investigate the outcome of the site of infection and concentration of L. braziliensis parasites inoculated on the immunopathogenesis and clinical evolution. Initially, hamsters were infected in the ear dermis or hind footpad with a concentration of 1 × 105 parasites. Animals infected in the ear dermis developed a disease, with an increased parasite load that more closely resembled human cutaneous leishmaniasis lesions comparing to the group infected in the footpad. Next, we evaluated if different parasite concentrations (104 , 105 and 106 ) inoculated in the ear dermis would impact the course and clinical aspects of infection. Hamsters infected with 104 and 105 parasites developed mild lesions compared to the group infected with 106 that presented severe and persistent lesions. The parasite load varied between the different parasite concentrations. The inflammatory response was more intense when infection was initiated with 106 parasites accompanied by an increased initial expression of IL-4, IL-10 and arginase in the lymph node followed by expression of both pro-and anti-inflammatory cytokines comparing to groups infected with 104 and 105 parasites. In conclusion, the number of parasites inoculated, and the initial site of infection could influence the inflammatory response, and clinical presentation. Our results suggest that the ear dermis infection model induces a chronic disease that relates to immunopathological aspects of CL natural infection.