Abstract Background: Chagas disease is considered important and presents intense inflammatory and fibrotic processes induced by the perpetuation of the parasite in the affected tissues and organs. Therefore, it is necessary to inquire about the host defense and attack mechanisms to have a more detailed knowledge about Chagas disease. Micro-RNAs are found in blood, tissues and extracellular vesicles. These small regulators of gene expression are involved in physiological and pathological processes in both mammals and parasites. Several microRNAs have deregulated expression in chagasic heart disease, although little is known about their extracellular expression. Our main objective was to evaluate the involvement of miR-21, miR-146a and miR-155 in several samples from mice infected with the TcI Ninoa strain from the acute and indeterminate phases. We also explored a potential functional association of the selected microRNAs using STRING software. This software identified 23 pathways associated with Trypanosoma cruzi infection. In addition, eleven genes were identified through bioinformatics analysis, and we found that SMAD family member 5 was downregulated in both phases. This gene serves as a mediator in the TGF-β signaling pathway. Thus, forty female mice of the CD1 strain were distributed into 4 groups and the expression levels of miR-21, miR-146a and miR-155 were measured in samples of heart tissue, total plasma and plasma extracellular vesicles by quantitative real-time polymerase chain reaction. Results: Overexpression of miR-21, miR-146a and miR-155 was observed in heart and plasma in both phases. Moreover, in extracellular vesicles miR-21 and miR-146a were also overexpressed in the acute phase, whereas in the indeterminate chronic phase we found only miR-146a up-regulated. Conclusions: The expression of inflammatory microRNAs miR-21, miR-146a and miR-155 were up-regulated in each of the samples from acutely and chronically infected mice. The relevant finding was that miR-146a was up-regulated in each sample in both phases; therefore, this miRNA could be a possible candidate biomarker in Chagas disease.

The case of a 50 years old man, coming from an endemic Chagas' disease zone, is reported. This patient came with a dilated cardiomyopathy, likely of Chagasic etiology, and heart failure. He died in our Institute, were it was possible to register an ECG, and perform the necropsy, on the same day of his death. The ECG showed signs of heart chambers dilatation, inactive myocardium in subendocardial anterolateral regions of the left ventricle, and extensive subepicardial injury. The anatomical study demonstrated the four heart chambers dilatation, and a subendocardial fibrosis essentially located in anterolateral portions of the left ventricle. The histological examination proved that the distribution of injured zones corresponded to location of the inflammatory foci. Furthermore, Trypanosoma cruzi inoculation in mice produced inflammatory foci, predominantly located in the ventricular epicardial and subepicardial regions.

Se presenta el caso de un hombre de 50 años, campesino proveniente de una zona endémica de enfermedad chagásica, que padecía de miocardiopatía dilatada, verosímilmente chagásica. Este enfermo llegó en insuficiencia cardíaca y falleció a los pocos días. En el mismo día de su defunción, pudo registrarse un ECG y efectuar la necropsia. El ECG proporcionó signos de dilatación de las cámaras cardíacas, de miocardio inactivable con localización subendocárdica, en regiones anterolaterales del ventrículo izquierdo, y de lesión subepicárdica extensa. El examen anatómico demostró la dilatación de las cuatro cavidades cardíacas y la existencia de fibrosis subendocárdica localizada esencialmente en porciones anterolaterales del ventrículo izquierdo. El estudio histológico reveló la correspondencia de la distribución de los focos inflamatorios con la de la lesión mencionada: regiones epicárdicas y subepicárdicas del ventrículo izquierdo. A su vez la inoculación de Trypanosoma cruzien ratones provocó la formación de focos de inflamación linfocitaria netamente predominantes en regiones epicárdicas y subepicárdicas de los ventrículos.

Iatrogenous transmission of Trypanosoma cruziby blood transfusion was suggested as a potential risk by Pellegrino (1949). Seropositive blood donors in Mexico were first reported in 1978, however, limited information is available due to small sampling, the use of heterogeneous serologic assays, and geographically limited studies. A wide survey carried out in 18 out of the 32 states of Mexico, showed a national mean of 1.6% seropositive among 64,969 donors, ranging from 0.2 to 2.8%. In the present study, we have screened 43,048 voluntary blood donors in a period of five years at the Instituto Nacional de Cardiología I. Chávez, a concentration hospital located in Mexico city which serves mainly the metropolitan area and accepts from all over the country. Standardized ELISA and IIF were used to identify seropositive individuals in addition to hemoculture, PCR and standard 12 lead ECG tests that were applied to a group of seropositive patients (29/161). The result showed a seropositivity of 0.37% (161/43,048). From the group of seropositive individuals 40% (12/29) were potential carriers of T. cruzi at the donation time and 5/29 had subclinical ECG abnormalities. Parasitological tests performed in 70 erythrocyte and platelet fractions from seropositive units (70/161) showed negative results. Our findings strongly support T. cruzi screening in the transfusion medicine practice and identify subclinical heart disease among seropositive blood donors.

Foi feito um estudo sorológico em quatro zonas geográficas do estado de Chiapas México. Foram colhidas 1333 amostras dos habitantes das 13 comunidades situadas na costa, na região central montanhosa, na floresta lacandona e na região chamada mesochiapas. Cento cinqüenta e uma pessoas (11,3%) foram identificadas como soropositivas. A infecção pelo Trypanosoma cruzi teve a influência da geografia local. Na floresta lacandona nas montanhas centrais, foi encontrada uma prevalência de 32,1 e 13,8% respectivamente, mais que na costa 1,2%. Na zona de mesochiapas não foi encontrada nenhuma pessoa com sorologia positiva entre 137 estudadas. Como encontramos sorologia positiva em crianças menores de 10 anos, pensamos que exista uma transmissão ativa contínua. Na costa foi reconhecido o vetor Triatoma dimidiata e na floresta Lacandona o Rhodnius prolixus.

A serologic survey was carried out in four different geographic zones of Chiapas, Mexico. A total of 1,333 samples were collected from residents of thirteen communities located on the Coast, Central Mountain, Lacandon Forest and a zone called Mesochiapas. One hundred and fifty one seropositive individuals (11.3%) were identified. Human Trypanosoma cruzi infection was influenced by geography. In the Lacandon Forest and Central Mountains there was a higher seroprevalence 32.1 and 13.8% respectively, than on the coast (1.2%). In Mesochiapas there were no seropositive individuals among the 137 persons tested. An active transmission is probably continuing because seropositive cases (13.8%) were detected in children under 10 years of age. The vector recognized on the Coast was Triatoma dimidiata while in the Lacandon Forest it was Rhodnius prolixus.