Therapeutic responses to different anti-Trypanosoma cruzi drugs in experimental infection by benznidazole-resistant parasite stock

This study describes the role of parasite clearance time induced by benznidazole, fexinidazole and posaconazole treatments upon mice infection with a benznidazole-resistant Trypanosoma cruzi strain in the pathological outcomes. Trypanosoma cruzi-infected mice were treated with different drugs and parasite clearance time was detected by blood and tissue qPCR, to determine the dynamic relationship between the efficacy of the treatments and the intensity of heart lesion/serum inflammatory mediators. Our results indicate that anti-T. cruzi treatments were able to reduce parasite replication and consequently induce immunomodulatory effects, where the degree of the immunopathology prevention was related to the time of parasite clearance induced by different treatments. Nevertheless, in benznidazole and posaconazole treatments, parasite rebounding was detected with parasitism reaching levels similar to infected and non-treated mice; the time for parasitic rebound being earlier among benznidazole-treated mice. In parallel, an increase of cardiac lesions and plasma chemokine levels was also detected and was more accentuated in benznidazole-treated animals. Interestingly, in the presence of parasitological cure (fexinidazole treatment), basal levels of these inflammatory mediators were evidenced as well as an absence of cardiac inflammation or fibrosis. Overall, our data indicate that all treatments have positive effects on the clinical evolution of T. cruzi infection, with success in preventing cardiac alterations being drug-dependen

Natural trypanocidal product produced by endophytic fungi through co-culturing

Endophytic fungi live inside vegetal tissues without causing damage to the host plant and may provide lead compounds for drug discovery. The co-culture of two or more endophytic fungi can trigger silent gene clusters, which could lead to the isolation of bioactive compounds. In this study, two endophytic strains isolated from Handroanthus impetiginosus leaves, identified as Talaromyces purpurogenus H4 and Phanerochaete sp. H2, were grown in mixed and axenic cultures. The meroterpenoid austin was detected only in the extracts from the mixed culture. Once isolated, austin displayed very interesting trypanocidal activity, with an IC50 value of 36.6 ± 1.2 μg/mL against Trypanosoma cruzi in the epimastigote form. The results obtained highlight the importance of the co-culturing of endophytic fungi to obtain natural bioactive products. The findings also enhance our understanding of the ecological relationships between endophytic fungi.Fil: do Nascimento, Jainara Santos. Universidade Federal da Bahia; BrasilFil: Silva, Felipe Moura. Universidade Federal da Bahia; BrasilFil: Magallanes Noguera, Cynthia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Investigaciones en Tecnología Química. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Química; ArgentinaFil: Kurina Sanz, Marcela Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Investigaciones en Tecnología Química. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Química; ArgentinaFil: dos Santos, Elda Gonçalves. Universidade Federal da Bahia; BrasilFil: Caldas, Ivo Santana. Universidade Federal da Bahia; BrasilFil: Luiz, Jaine Honorata Hortolan. Universidade Federal da Bahia; BrasilFil: Silva, Eliane de Oliveira. Universidade Federal da Bahia; Brasi

Resistin and visfatin concentrations are related to central obesity and inflammation in Brazilian children.

Background: The evidence that cardiovascular disease begins in childhood and adolescence, especially in the presence of excess weight, is associated with dysfunction on adipokine pro-inflammatory secretion. These affect glucose metabolism and lead to other complications related to insulin resistance and cardiovascular disease. This study assessed the association of anthropometric and metabolic parameters related to obesity, cardiovascular risk, and insulin resistance with concentrations of resistin and visfatin, in children. Methods: A cross-sectional study was developed with 178 children of 6?10 years old enrolled in public city schools. Anthropometric data, composition body, clinical, and biochemical were measured according to standard procedures. We used multiple regression models by stepwise method to evaluate the associations of resistin and visfatin with variables of interest. Results: In healthy weight children, resistin was associated with LDL cholesterol, visfatin, atherogenic index, and waist-to-height ratio, whereas in obese children resistin was associated with visfatin and interaction between conicity index and HOMA-AD. Furthermore, in healthy weight children, visfatin was associated to resistin and triceps skinfold thickness and negatively associated to HOMA-AD, while in obese ones visfatin was associated with waistto- height ratio, atherogenic index, resistin, and interaction between trunk adiposity index and adiponectin and was negatively associated with the HOMA-IR index. Conclusions: Our study shows an association between anthropometric and biochemical variables related to visceral fat and inflammation. These results suggest the resistin and visfatin as good pro-inflammatory markers. In addition, both adipokines are strongly related to central obesity, in children

Hematological alterations during experimental canine infection by Trypanosoma cruzi

To confirm that Beagle dogs are a good experimental model for Chagas disease, we evaluated hematological alterations during the acute and chronic phases in Beagle dogs infected with the Y, Berenice-78 (Be-78) and ABC strains of Trypanosoma cruzi, correlating clinical signs with the parasitemia curve. We demonstrate that the acute phase of infection was marked by lethargy and loss of appetite. Simultaneously, we observed anemia, leukocytosis and lymphocytosis. Also,we describe hematological alterations and clinical signs that were positively correlated with the parasitemia during the experimental infection with the three strains of T cruzi, and demonstrate that experimental infection of Beagle is a trustworthy model for Chagas disease.Research Support Foundation of the State of Minas Gerais (FAPEMIG)Research Support Foundation of the State of Minas Gerais (FAPEMIG)National Research Council for Scientific and Technological Development (CNPq)National Research Council for Scientific and Technological Development (CNPq)Coordination Office for Advancement of Universitylevel Personnel (CAPES)Coordination Office for Advancement of University-level Personnel (CAPES

IgG isotype profile is correlated with cardiomegaly in Beagle dogs infected with distinct Trypanosoma cruzi strains.

A systematic study following infection by various strains of the protozoan parasite, Trypanosoma cruzi, and the simultaneous monitoring of the humoral immune response together with the elicited cellular response, could add greatly to our understanding of differences between strains of this important human pathogen. In that sense, acute and chronic infections with distinct T. cruzi strains (Y, Berenice-78 and ABC) in Beagle dogs were studied through a longitudinal evaluation of immunoglobulin G (IgG), IgG1 and IgG2 isotypes (by ELISA and flow cytometry (FC)), as well as measurements of peripheral blood mononuclear cell (PBMC) proliferation over a 100-week period, and their correlation with cardiomegaly. Our results show that infected animals presenting cardiomegaly showed lower or absent levels of IgG1 during the chronic phase of the infection, when compared to those that did not show an increase in heart weight. In that manner, our results suggest that IgG1 could be used as a marker for cardiac pathogenicity in Chagas disease

Avaliação da eficácia do tratamento específico com Benznidazol na progressão da doença de Chagas Experimental e a correlação entre a eficácia do tratamento nos modelos canino e murino.

Neste trabalho foi avaliado o benefício do tratamento precoce da doença de Chagas experimental na diminuição das lesões cardíacas de cães e camundongos inoculados com cepas sensíveis (Be-78), parcialmente sensíveis (Y, ABC e AAS) e resistentes (VL10) ao Benznidazol. Em adição, foi avaliada a influência do tratamento específico na evolução dos anticorpos da classe IgG e das subclasses IgG1 e IgG2 (cães) e IgG1, IgG2a e IgG2b (camundongos) na tentativa de identificar um novo marcador sorológico para ser utilizado no controle de cura da doença de Chagas. O tratamento com Benznidazol previniu a inflamação e a fibrose no miocárdio de todos os cães e camundongos experimentalmente infectados que alcançaram a cura parasitológica, exceto nos cães inoculados com a cepa Y do T.cruzi, que apresentaram fibrose. Entre os cães tratados e não curados o tratamento induziu a diferentes padrões de resposta: (1) não foi observada redução da inflamação e nem da fibrose no tecido cardíaco dos animais inoculados com as cepas ABC e VL10, (2) redução das lesões cardíacas dos cães não curados inoculados com a cepa AAS. De forma diferente, o tratamento específico não foi capaz de diminuir a intensidade de inflamação no miocárdio de nenhum camundongo tratado e não curado inoculado com as cepas ABC, AAS e VL10, entretanto preveniu a fibrose entre os animais inoculados com a cepa VL10. Os resultados da dosagem de anticorpos específicos mostraram que a intensidade da inflamação no miocárdio dos animais inoculados com as diferentes cepas do T. cruzi e não tratados pode ser correlacionada com os níveis de IgG1 nos dois modelos experimentais usados neste estudo. Foi observado que quanto maior é o infiltrado inflamatório no miocárdio de camundongos e cães inoculados com as cepas Be-78, Y, ABC, AAS e VL10 do T.cruzi, maiores são os níveis de IgG1 detectados no soro. O tratamento específico induziu uma redução nos níveis de todas as classes e subclasses de imunoglobulinas avaliadas. Entretanto a negativação da sorologia foi observada apenas nos animais tratados e curados, nos tratados que não alcançaram a cura parasitológica os níveis de todas as classes e subclasses de imunoglobulinas avaliadas atingiram níveis próximos ao observado nos soros dos animais controle infectado.In this present work, it was evaluated the benefit of precocious Benznidazole (Bz) treatment of experimental Chagas disease in reduce cardiac lesions in dogs and mice previously inoculated with sensitive (Be-78), partially sensitive (Y, ABC and AAS) and resistant (VL-10) strains of Trypanosoma cruzi. In addition, it was also evaluated the interference of this specific Bz treatment on the standard of mice (IgG, IgG1 and IgG2) and dogs (IgG1, IgG2a and IgG2b) antibodies in the attempt to correlate them with suggestive circulating markers of cure criteria during Chagas disease. Bz treatment was able to prevent inflammation and fibrosis in heart from infected dogs and mice that reached parasitological cure, except in those treated dogs inoculated with Y strain of T. cruzi that presented cardiac fibrosis. Among Bz treated and not cured dogs, it was observed: (i) no reduction on the inflammation and fibrosis in those animals inoculated with ABC and VL-10 strains; (ii) reduction on cardiac lesions in those inoculated with AAS strain. On the other hand, in murine model, the specific treatment was not able to reduce the inflammation intensity in those mice treated and not cured previously infected with ABC, AAS and VL-10 strains. In this case, Bz effectively prevented cardiac fibrosis in all mice inoculated with VL-10 strain. Interestingly, serological investigation demonstrated a close relation between high levels of IgG1 and intensity of cardiac inflammation in all not-treated animals (dogs and mice) when they were infected with different T. cruzi strains. The specific Bz treatment induced a significant reduction in levels all immunoglobulins investigated. However, a negative serological data was just observed in those treated and cured animals while similar results were observed between immunoglobulins from those treated and not-cured and infected control animals. Our data suggest that specific Benznidazole treatment prevents cardiac lesions in animals that reached parasitological cure and circulating immunoglobulins appears as promising markers of “cure criteria” during experimental Chagas disease

Impacto do tratamento com Benznidazol na evolução da doença de Chagas experimental - análise imunopatológica e funcional.

Considerando as controvérsias sobre a eficácia do tratamento específico com Benznidazol (Bz) na prevenção ou redução das lesões cardíacas crônicas, este projeto propôs avaliar a influência do tratamento específico na evolução da cardiopatia chagásica, utilizando como modelo experimental cães infectados por cepas do Trypanosoma cruzi sensíveis e resistentes ao Bz. As avaliações imunopatológicas e clínicas foram realizadas utilizando: (i) a avaliação da área ocupada pela inflamação e pela fibrose no músculo cardíaco (ii) avaliação dos níveis de expressão mRNA para citocinas no tecido cardíaco; (iii) avaliação da resposta proliferativa e morte por apoptose de células mononucleares do sangue periférico (CMSP) e quantificação da produção de citocinas no sobrenadante das CMSP dos animais ao longo da infecção; (iv) avaliação das possíveis interferências do tratamento com Bz sobre a evolução clínica da cardiopatia experimental, através da detecção das alterações eletrocardiográficas, em cães chagásicos tratados e não tratados. Nossos resultados mostraram que o tratamento específico induziu 100% de cura nos animais infectados pela cepa Berenice-78, e que não houve cura parasitológica entre os infectados pelas cepas VL-10 e AAS. O tratamento específico, de maneira geral, preveniu as lesões cardíacas dos animais curados, bem como as alterações eletrocardiográficas. De forma interessante, entre os animais não curados foi observado um padrão de resposta variável de acordo com a população do T. cruzi. Nos animais infectados pela cepa AAS foi detectada redução significativa do processo inflamatório e da fibrose no tecido cardíaco acompanhado de ausência de alterações eletrocardiográficas. De forma diferente, entre os animais infectados pela cepa VL-10, o tratamento não foi eficaz em reduzir tanto as lesões cardíacas quanto as alterações eletrocardiográficas. Os parâmetros imunológicos avaliados durante as fases aguda e crônica da infecção foram marcadamente influenciados tanto pela cepa do parasito quanto pelo tratamento específico. Foi possível correlacionar a intensidade das lesões cardíacas e a produção de imunoglobulinas (IgG, IgG1, IgG2) no soro e de citocinas (TNF-, IFN- e IL-10) no sobrenadante de CMSP, além da expressão de mRNA dessas citocinas no tecido cardíaco dos animais submetidos ou não à quimioterapia com o Bz. De forma geral, nossos resultados contribuirão para uma melhor compreensão do benefício do tratamento específico na evolução clínica e nos mecanismos imunopatológicos envolvidos na doença de Chagas.Based on the divergences concerning the efficacy of anti-Trypanosoma cruzi treatment with Benznidazol (Bz) in the prevention and reduction of cardiac chronic lesions, the aim of this study was evaluate the influence of Bz in the evolvement of the Chagas cardiopathy using dog models infected with Bz-resistent and – susceptible strains of parasites. Clinical and immunopathology parameters were performed through evaluation of the: (i) inflammation and fibrosis area in cardiac muscle; (ii) mRNA expression of cytokines in cardiac tissue; (iii) proliferative response, apoptosis and quantification of cytokines in peripheral blood mononuclear cells (PBMC) and their supernatant, respectively; and (iv) interferences of Bz on the clinical evolving thought electrocardiography (ECG) alterations in infected dogs treated or not with Bz. Our data showed that Bz-treatment induced 100% of cure in animals infected with Berenice-78 strain and absence of cure in those infected with VL-10 and AAS strains of parasite. In the presence of cure, there were prevention of cardiac lesions and ECG alterations and, among not cured animals, it was observed a variable pattern of immunopathology and clinical aspects according to the T. cruzi genetic population. Interestingly, AAS strain was associated with reduction of inflammatory infiltration and fibrosis in heart tissue as well as absence of ECG alterations while VL-10 strain was not able to ameliorate these parameters. Immune aspects evaluated during acute and chronic phases were influenced by parasite strains and by Bz-treatment. Following this, intensity of cardiac lesions was correlated with high serum production of immunoglobulins (IgG, IgG1, IgG2) and with the release and expression of cytokines (TNF-, IFN- e IL-10) in CMSP supernatant and cardiac tissue, respectively, in those animals submitted or not to Bz-treatment. In summary, our data will contribute to define the benefits of Bz-treatment to the clinical evolving as well as to comprehend the immunopahtological mechanisms associated with Chagas disease

Outcome of E1224-Benznidazole combination treatment for infection with a multidrug-resistant Trypanosoma cruzi strain in mice.

Combination therapy has been proposed as an alternative therapeutic approach for the treatment of Chagas disease. In this study, we evaluated the effect of treatment with benznidazole combined with E1224 (ravuconazole prodrug) in an experimental murine model of acute infection. The first set of experiments assessed the range of E1224 doses required to induce parasitological cure using Trypanosoma cruzi strains with different susceptibilities to benznidazole (Y and Colombian). All E1224 doses were effective in suppressing the parasitemia and preventing death; however, parasitological cure was observed only in mice infected with Y strain. Considering these results, we evaluated the effect of combined treatment against Colombian, a multidrug-resistant T. cruzi strain. After exclusion of antagonistic effects using in vitro assays, infected mice were treated with E1224 and benznidazole in monotherapy or in combination at day 4 or 10 postinoculation. All treatments were well tolerated and effective in suppressing parasitemia; however, parasitological and PCR assays indicated no cure among mice treated with monotherapies. Intriguingly, the outcome of combination therapy was dependent on treatment onset. Early treatment using optimal doses of E1224-benznidazole induced a 100% cure rate, but this association could not eliminate a well-established infection. The beneficial effect of combination therapy was evidenced by further reductions of the patent parasitemia period in the group receiving combined therapy compared with monotherapies. Our results demonstrated a positive interaction between E1224 and benznidazole against murine T. cruzi infection using a multidrug-resistant strain and highlighted the importance of a stringent experimental model in the evaluation of new therapies

Benznidazole therapy during acute phase of chagas disease reduces parasite load but does not prevent chronic cardiac lesions.

The goals of this study were to evaluate the efficacy of benznidazole (Bz) treatment in decreasing of the parasitic load during the acute phase of experimental Chagas disease and to analyze its influence in the development of cardiac chronic alterations in mice inoculated with drug-resistant Trypanosoma cruzi strains. Our results showed that the early Bz treatment (started at 4th day of infection) was efficient in reducing the parasite load in animals from both acute and chronic phase of the infection. Moreover, this reduction in the parasite load could not be associated with the intensity of the cardiac chronic lesions. The histopathological evaluation of cardiac tissue of Bz-treated mice showed three different patterns of response: (1) presence of a small number of inflammatory cells and fibrotic area similar to noninfected mice; (2) similar intensity of inflammatory infiltrate and smaller fibrotic area in relation to nontreated animals; (3) similar intensity of inflammatory infiltrated and fibrosis area among the Bz-treated and nontreated animals. Each specific pattern was obtained with different T. cruzi strain, suggesting that the pattern of the heart lesions in chronic phase of Bz-treated animals was T. cruzi strain dependent but not related with drug resistance levels

Therapeutic responses to different anti-Trypanosoma cruzi drugs in experimental infection by benznidazole-resistant parasite stock.

upon mice infection with a benznidazole-resistant Trypanosoma cruzi strain in the pathological outcomes. Trypanosoma cruzi-infected mice were treated with different drugs and parasite clearance time was detected by blood and tissue qPCR, to determine the dynamic relationship between the efficacy of the treatments and the intensity of heart lesion/serum inflammatory mediators. Our results indicate that anti-T. cruzi treatments were able to reduce parasite replication and consequently induce immunomodulatory effects, where the degree of the immunopathology prevention was related to the time of parasite clearance induced by different treatments. Nevertheless, in benznidazole and posaconazole treatments, parasite rebounding was detected with parasitism reaching levels similar to infected and non-treated mice; the time for parasitic rebound being earlier among benznidazole-treated mice. In parallel, an increase of cardiac lesions and plasma chemokine levels was also detected and was more accentuated in benznidazole-treated animals. Interestingly, in the presence of parasitological cure (fexinidazole treatment), basal levels of these inflammatory mediators were evidenced as well as an absence of cardiac inflammation or fibrosis. Overall, our data indicate that all treatments have positive effects on the clinical evolution of T. cruzi infection, with success in preventing cardiac alterations being drug-dependent