RESUMO

Infection by the protozoan Trypanosoma cruzi causes Chagas disease cardiomyopathy (CCC) and can lead to arrhythmia, heart failure and death. Chagas disease affects 8 million people worldwide, and chronic production of the cytokines IFN-γ and TNF-α by T cells together with mitochondrial dysfunction are important players for the poor prognosis of the disease. Mitochondria occupy 40% of the cardiomyocytes volume and produce 95% of cellular ATP that sustain the life-long cycles of heart contraction. As IFN-γ and TNF-α have been described to affect mitochondrial function, we hypothesized that IFN-γ and TNF-α are involved in the myocardial mitochondrial dysfunction observed in CCC patients. In this study, we quantified markers of mitochondrial dysfunction and nitro-oxidative stress in CCC heart tissue and in IFN-γ/TNF-α-stimulated AC-16 human cardiomyocytes. We found that CCC myocardium displayed increased levels of nitro-oxidative stress and reduced mitochondrial DNA as compared with myocardial tissue from patients with dilated cardiomyopathy (DCM). IFN-γ/TNF-α treatment of AC-16 cardiomyocytes induced increased nitro-oxidative stress and decreased the mitochondrial membrane potential (ΔΨm). We found that the STAT1/NF-κB/NOS2 axis is involved in the IFN-γ/TNF-α-induced decrease of ΔΨm in AC-16 cardiomyocytes. Furthermore, treatment with mitochondria-sparing agonists of AMPK, NRF2 and SIRT1 rescues ΔΨm in IFN-γ/TNF-α-stimulated cells. Proteomic and gene expression analyses revealed that IFN-γ/TNF-α-treated cells corroborate mitochondrial dysfunction, transmembrane potential of mitochondria, altered fatty acid metabolism and cardiac necrosis/cell death. Functional assays conducted on Seahorse respirometer showed that cytokine-stimulated cells display decreased glycolytic and mitochondrial ATP production, dependency of fatty acid oxidation as well as increased proton leak and non-mitochondrial oxygen consumption. Together, our results suggest that IFN-γ and TNF-α cause direct damage to cardiomyocytes' mitochondria by promoting oxidative and nitrosative stress and impairing energy production pathways. We hypothesize that treatment with agonists of AMPK, NRF2 and SIRT1 might be an approach to ameliorate the progression of Chagas disease cardiomyopathy.

Assuntos

RESUMO

Infection by the protozoan Trypanosoma cruzi causes Chagas disease cardiomyopathy (CCC) and can lead to arrhythmia, heart failure and death. Chagas disease affects 8 million people worldwide, and chronic production of the cytokines IFN-γ and TNF-α by T cells together with mitochondrial dysfunction are important players for the poor prognosis of the disease. Mitochondria occupy 40% of the cardiomyocytes volume and produce 95% of cellular ATP that sustain the life-long cycles of heart contraction. As IFN-γ and TNF-α have been described to affect mitochondrial function, we hypothesized that IFN-γ and TNF-α are involved in the myocardial mitochondrial dysfunction observed in CCC patients. In this study, we quantified markers of mitochondrial dysfunction and nitro-oxidative stress in CCC heart tissue and in IFN-γ/TNF-α-stimulated AC-16 human cardiomyocytes. We found that CCC myocardium displayed increased levels of nitro-oxidative stress and reduced mitochondrial DNA as compared with myocardial tissue from patients with dilated cardiomyopathy (DCM). IFN-γ/TNF-α treatment of AC-16 cardiomyocytes induced increased nitro-oxidative stress and decreased the mitochondrial membrane potential (ΔΨm). We found that the STAT1/NF-κB/NOS2 axis is involved in the IFN-γ/TNF-α-induced decrease of ΔΨm in AC-16 cardiomyocytes. Furthermore, treatment with mitochondria-sparing agonists of AMPK, NRF2 and SIRT1 rescues ΔΨm in IFN-γ/TNF-α-stimulated cells. Proteomic and gene expression analyses revealed that IFN-γ/TNF-α-treated cells corroborate mitochondrial dysfunction, transmembrane potential of mitochondria, altered fatty acid metabolism and cardiac necrosis/cell death. Functional assays conducted on Seahorse respirometer showed that cytokine-stimulated cells display decreased glycolytic and mitochondrial ATP production, dependency of fatty acid oxidation as well as increased proton leak and non-mitochondrial oxygen consumption. Together, our results suggest that IFN-γ and TNF-α cause direct damage to cardiomyocytes’ mitochondria by promoting oxidative and nitrosative stress and impairing energy production pathways. We hypothesize that treatment with agonists of AMPK, NRF2 and SIRT1 might be an approach to ameliorate the progression of Chagas disease cardiomyopathy.

RESUMO

Prospective sampling activities of intertidal invertebrates in the Ancon Bay (Lima, Peru) were done in order to select marine bacteria producing antimicrobial substances. The study included the isolation of bacteria in marine agar, in vitro antimicrobial susceptibility testing and electronic microscopic observations. We report the isolation, phenotypical characterization and antimicrobial properties of 10 strains of marine bacteria including the genus Vibrio, Pseudomonas, and Flavobacterium, and the order Actinomycetae that inhibit human pathogens. The results indicate that the marine invertebrates would be sources of bacteria producing antibiotic substances.

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Se realizó actividades prospectivas de muestreo de invertebrados intermareales en la Bahía de Ancón (Lima - Perú) con el objetivo de seleccionar bacterias marinas productoras de sustancias antimicrobianas. El estudio comprendió el aislamiento de bacterias en agar marino, pruebas de susceptibilidad antimicrobiana in vitro y observaciones de microscopía electrónica. Se reporta el aislamiento, caracterización fenotípica y propiedades antimicrobianas de diez cepas de bacterias marinas que incluyen a los géneros Vibrio, Pseudomonas y Flavobacterium y del orden Actinomycetal que inhiben a patógenos de humanos. Los resultados indicarían que los invertebrados marinos serían fuentes de bacterias productoras de sustancias antibióticas.

Prospective sampling activities of intertidal invertebrates in the Ancon Bay (Lima, Peru) were done in order to select marine bacteria producing antimicrobial substances. The study included the isolation of bacteria in marine agar, in vitro antimicrobial susceptibility testing and electronic microscopic observations. We report the isolation, phenotypical characterization and antimicrobial properties of 10 strains of marine bacteria including the genus Vibrio, Pseudomonas, and Flavobacterium, and the order Actinomycetae that inhibit human pathogens. The results indicate that the marine invertebrates would be sources of bacteria producing antibiotic substances.

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RESUMO

OBJECTIVE: To evaluate whether prophylactic chemotherapy (P-chem) with one bolus dose of actinomycin D (Act-D) during the uterine evacuation of patients with high-risk hydatidiform mole (Hr-HM) affects reproductive outcomes in subsequent pregnancies. METHODS: From 1987 to 2006, 1090 patients with gestational trophoblastic disease (GTD) were evaluated at a Trophoblastic Disease Center in southern Brazil; 265 with Hr-HM were selected and retrospectively analyzed. From 1996 to 2006, 163 received one bolus dose of Act-D at the time of uterine evacuation (Hr-HM-chem group); 102 with the same risk factors did not get P-chem (Hr-HM-control group). In March 2009, the number of pregnancies, progression of first pregnancy, and association of low age and low parity with subsequent pregnancy were evaluated. RESULTS: The percentage of patients that became pregnant was similar in both groups (Hr-HM-control: 59.5%; Hr-HM-chem group: 45.7%; p=0.069) and independent of HM progression. Percentages of no pregnancies because of age (> or =40 years) or hysterectomy were also similar. Type of subsequent pregnancy was not statistically different between groups, and the rate of live births associated with pregnancies for which US showed a live fetus was high. Frequency of repeat GTD was unexpectedly high in both groups (4.2% and 6.3%; p=1.00). CONCLUSIONS: P-chem did not affect reproductive outcomes for patients with Hr-HM. Patients allowed to become pregnant again in both groups had high rates of live births associated with normal pregnancies. Chances of a subsequent pregnancy were higher in the low age and low parity subgroups.

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Se presenta la experiencia en el manejo de lesiones subclínicas de la glándula mamaria mediante biopsia radioquirúrgica en 31 pacientes asintomáticas entre febrero 1996 y abril 1999, en el Instituto de Clínicas y Urología Tamanaco, a quienes se les realizó mastectomía parcial previa localización con mamografía y/o ecosonograma mamario, utilizando marcajes con colorante y/o arpón. Resultados: el rango etario está comprendido entre los 35 y los 69 años, la relación de lesiones benignas/malignas es de 3,8:1, con un porcentaje de lesiones subclínicas malignas diagnósticas y tratadas del 25,80 por ciento. En el grupo etario comprendido entre los 50-59 años se presentó el mayor porcentaje de lesiones subclínicas malignas (16.12 por ciento), observándose que en el grupo de lesiones subclínicas tipo microcalcificaciones en el 42 por ciento de los casos fueron lesiones malignas de la glándula mamaria. Con respecto al tipo de tratamiento realizado en los casos de carcinoma ductal in situ y se realizaron cirugías preservadoras de la mama en los 3 pacientes, más radioterapia en 1 de los casos; en los pacientes con carcinoma ductal infiltrante el tratamiento fue tratamiento preservador de la mama que incluye mastectomía parcial oncológica, disección axilar y radioterapia a la glándula mamaria en todos los casos, observandose metástasis axilar en solamente 1 de ellos. Discusión: la utilización de la mamografía como método de pesquisa ha permitido el diagnóstico y tratamiento de un número mayor de lesiones malignas tempranas de la glándula mamaria, siendo la biopsia radioquirúrgica un procedimiento común, útil y frecuente en el manejo de éstas lesiones, con garantías de éxito en un equipo de trabajo multidisciplinario, mientras se logran desarrollar otros métodos menos invasivos en el diagnóstico de lesiones tanto benignas como malignas de la glándula mamaria

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