Mechanism of Trypanosoma cruzi Placenta Invasion and Infection: The Use of Human Chorionic Villi Explants

Congenital Chagas disease, a neglected tropical disease, endemic in Latin America, is associated with premature labor and miscarriage. During vertical transmission the parasite Trypanosoma cruzi (T. cruzi) crosses the placental barrier. However, the exact mechanism of the placental infection remains unclear. We review the congenital transmission of T. cruzi, particularly the role of possible local placental factors that contribute to the vertical transmission of the parasite. Additionally, we analyze the different methods available for studying the congenital transmission of the parasite. In that context, the ex vivo infection with T. cruzi trypomastigotes of human placental chorionic villi constitutes an excellent tool for studying parasite infection strategies as well as possible local antiparasitic mechanisms

Antiparasitic Mechanisms of the Human Placenta

Trypanosoma cruzi, during vertical transmission, crosses the placental barrier. The trophoblast, a continuous renewing epithelium, is the first tissue of this anatomical barrier to have contact with the parasite. The epithelial turnover, including the trophoblast, is part of the innate immune response due to the fact that pathogens attach to the surface of cells prior invasion. Cellular processes such as proliferation, differentiation, and apoptotic cell death are part of the trophoblast turnover. Interestingly, T. cruzi induces all of them. In addition, the placenta expresses TLRs, whose activation leads to the secretion of pro-inflammatory and immunomodulating cytokines. T. cruzi is recognized by TLR-2, TLR-4, TLR-7, and TLR-9. In the present review, we analyze the current evidence about the trophoblast epithelial turnover, the induction of a specific cytokine profile as a local placental innate immune response, as well as other possible defense mechanisms against the parasite

Congenital Transmission of Trypanosoma cruzi: A Review About the Interactions Between the Parasite, the Placenta, the Maternal and the Fetal/Neonatal Immune Responses

Chagas disease (CD), caused by the protozoan parasite Trypanosoma cruzi, is considered a neglected tropical disease by the World Health Organization. Congenital transmission of CD is an increasingly relevant public health problem. It progressively becomes the main transmission route over others and can occur in both endemic and non-endemic countries. Though most congenitally infected newborns are asymptomatic at birth, they display higher frequencies of prematurity, low birth weight, and lower Apgar scores compared to uninfected ones, and some suffer from severe symptoms. If not diagnosed and treated, infected newborns are at risk of developing disabling and life-threatening chronic pathologies later in life. The success or failure of congenital transmission depends on interactions between the parasite, the placenta, the mother, and the fetus. We review and discuss here the current knowledge about these parameters, including parasite virulence factors such as exovesicles, placental tropism, potential placental defense mechanisms, the placental transcriptome of infected women, gene polymorphism, and the maternal and fetal/neonatal immune responses, that might modulate the risk of T. cruzi congenital transmission.This work was supported by the ERANET-LAC grants ELAC2014/HID-0328 and ERANet17/HLH-0142 (to UK, AO, AS, and CT), FONDECYT 1190341 (Conicyt, Chile to UK), and PICT 2015-0074 (FONCyT, Argentina to AS)

Alteraciones en la proliferación celular y muerte celular programada tipo apoptosis en muestras de carcinoma de células escamosas de mucosa oral

56 p.El carcinoma de células escamosas de la cavidad oral (CCECO) representa el 90% de las neoplasias malignas bucales. La carcinogénesis oral se ha vinculado a daños genéticos no letales, especialmente en secuencias de genes supresores de tumores y oncogenes. Estas mutaciones y otros mecanismos permiten a las células proliferar a un ritmo que supera la muerte celular, especialmente la de tipo apoptosis. Este desbalance se debe tanto al aumento en la proliferación como a una disminución de la muerte celular. Así, la desregulación de la muerte celular tipo apoptosis también juega un rol fundamental en el proceso de carcinogénesis.El objetivo del presente estudio fue analizar la posible desregulación de proliferación tumoral (determinada mediante la expresión de marcadores de proliferación tumoral) y muerte celular tipo apoptosis en el CCECO. Se estudiaron 5 muestras correspondientes a biopsias incisionales de CCECO obtenidas de la Unidad de Diagnostico Oral e Histopatología de las Clínicas Odontológicas de la Facultad de Ciencias de la Salud, Universidad de Talca. Éstas fueron sometidas a análisis inmunohistoquímico para el antígeno de proliferación celular nuclear (PCNA) y el gen supresor de tumores p53. Las muestras fueron analizadas adicionalmente con el método histoquímico de detección de Regiones Organizadoras de Nucléolos (Técnica AgNOR). La posible muerte celular tipo apoptosis fue determinada mediante el método de TUNEL (TdT-mediated dUTP Nick-End Labeling). Los resultados de nuestro estudio confirman que el CCECO presenta una desregulación de procesos celulares básicos, específicamente: 1) Aumento de la proliferación celular 2) Presencia de genes supresores de tumores mutados (p53) 3) Alteración en el patrón de maduración epitelial, manifestado por una alteración en la expresión normal de células TUNEL+ en el epitelio./ABSTRACT:Oral squamous cell carcinoma (OSCC) represents the 90% of the oral malignant neoplasms. The oral carcinogenesis has been related to non-lethal genetic damage, especially in tumor-supressor genes and oncogenes. These mutations and other deregulated mechanisms results in an increased cellular proliferation rate that overtake the cell death rate, the latter one is additionally decreased. Therefore, cell death deregulation, specially apoptotic cell death, plays a fundamental role in the oral carcinogenesis.The principal aim of the present study was to analyze the possible deregulation of cellular proliferation (determined by proliferation markers) and the apoptotic cell death in OSCC. We analyzed five samples of incisional biobsies of OSCC from the “Unidad de Diagnostico Oral e Histopatología de las Clínicas Odontológicas de la Facultad de Ciencias de la Salud, Universidad de Talca”. Immunohistochemistry for the proliferating celular nuclear antigen (PCNA) and the p53 tumor suppressor gene was performed. Additionally, nucleolar organizer regions (AgNORs) were analyzed histochemically and DNA fragmentation was determined by the TUNEL (TdT-mediated dUTP Nick- End Labeling) method.Our results confirm that OSCC present deregulation of basic cellular processes, specifically: 1) Increase in cell proliferation 2) Mutation of tumor suppressor genes 3) Alteration in normal epithelial differentiation, evidenced by altered expression of TUNEL+ cell

Determinación del efecto quimiopreventivo de quercetina en un modelo de carcinogénesis oral en ratones CF-1 expuestos a 4-nitroquinolina 1- oxido

104 p.El cáncer es un problema de salud pública a nivel mundial, afectando por igual a países desarrollados, como a los en vías en desarrollo. El cáncer orofaríngeo es una de las neoplasias más prevalentes (5,7%), afectando anualmente aproximadamente a 400.000 personas. En particular el carcinoma de células escamosas de la cavidad oral (CCECO) representa el 80% de estas neoplasias. El tratamiento de este tipo de cáncer es sumamente costoso y radical, lo que conlleva graves secuelas para el paciente durante toda su vida. La detección temprana de esta neoplasia es la mejor alternativa para impedir estas consecuencias.Quercetina es uno de los flavonoides más comunes y ampliamente distribuido en frutas y hortalizas. Es un potente antioxidante, que podría inducir respuestas celulares que contribuyan a disminuir la severidad de las neoplasias, convirtiéndolo en un candidato a ser un agente quimiopreventivo. Sin embargo, en la literatura se han reportado que la quercetina podría tener efectos oxidantes in vitro y que las dosis necesarias para obtener efectos antioxidantes in vivo son difícilmente aplicables.El objetivo de este estudio fue determinar el posible efecto quimiopreventivo de quercetina en CCECO inducido por 4-NQO. Para esto se utilizó un modelo de carcinogénesis químico murino determinando el efecto de quercetina sobre las lesiones preneoplásicas y neoplásicas, nivel de lipoperoxidación y glutatión reducido en sangre de ratones tratados. Además, se evaluó el potencial efecto tóxico del compuesto en cultivos celulares de fibroblastos pulmonares (MCR-5).Quercetina a bajas concentraciones previene la disminución de la viabilidad celular causada por 4-NQO, pero no mejora la sobrevida, ni la incidencia, ni la severidad de las lesiones preneoplásicas y de CCECO de ratones tratados con 4-NQO. Además mantiene bajos los niveles de GSH sanguíneo en ratones expuestos a 4-NQO y quercetina. Se concluye que Quercetina no presenta un efecto quimiopreventivo sobre las lesiones en la mucosa lingual de ratones sometidos a carcinogénesis experimental inducida por 4-NQO./ ABSTRACT: Cancer is a worldwide public health problem, affecting both developed and developing countries. Oropharyngeal cancer is one of the most prevalent carcinomas (5.7%), affecting approximately 400000 individuals annually. Squamous cell carcinoma of the oral cavity (SCCOC) represents 80% of these tumors. Treatment of this type of cancer is extremely expensive and radical, and has serious consequences for the patient throughout their lives. Early detection of this neoplasm is the best alternative to prevent these consequences. Quercetin is one of the most common and widely distributed flavonoids in fruits and vegetables. It is a powerful antioxidant which could induce cellular responses that might contribute to reduce the severity of tumors, making it a candidate as a chemopreventive agent. However, the scientific reports indicates that Quercetin may have oxidant effects in vitro and that the doses required for in vivo antioxidant effects are hardly applicable.The objetive of this study was to determine the potential chemopreventive effect of Quercetin over 4-NQO induced SCCOC in mice. We determined the effect of Quercetin on preneoplastic and neoplastic lesions, lipoperoxidation levels and reduced glutathione levels in the blood of treated animals. Additionally, the potential toxic effects on lung fibroblast cell cultures (MCR-5) was assessed. Quercetin at low concentrations prevent the decrease of cell viability caused by 4-NQO, but does not improve survival, nor the incidence or severity of preneoplastic lesions and SCCOC in mice treated with 4-NQO. Quercetin also maintains low blood GSH levels in CF-1 mice exposed to 4-NQO and quercetin. We conclude, that Quercetin has no chemopreventive effect on lesions in the lingual mucosa in mice subjected to experimental carcinogenesis with 4-NQO

Expresion de cambios histopatologicos reaccionales, pre-neoplasicos y/o neoplasicos en el epitelio de la mucosa lingual de ratones cf-1 expuestos a 4-nitroquinolina-1-oxido.

77 p.INTRODUCCIÓN: El cáncer oral es una enfermedad que afecta a 400.000 personas cada año. El CCECO representa aproximadamente el 90% de los casos. El desarrollo de modelos de carcinogénesis experimental en animales juega un papel fundamental para su estudio y el desarrollo de terapias. OBJETIVO: Inducir cambios histopatológicos reaccionales, pre-neoplásicos y/o neoplásicos en el epitelio de la mucosa lingual de ratones CF-1 al exponerlos a 4- nitroquinolina-1-oxido (4-NQO). MATERIALES Y MÉTODOS: Se aplicó una solución de 4NQO más propilenglicol diluido en el agua de bebida a 20 ratones, a una concentración de 100 μg/ml y se mantuvo un grupo control de igual tamaño solo con agua y propilenglicol. Esta sustancia se aplicó por un periodo de 16 semanas, después del cual se suspendió, esperando hasta las 28 semanas para realizar la biopsia de la lengua. Se analizó la presentación de lesiones clínicas (leucoplasia, eritroplasia y lesiones mixtas). Se procesó la totalidad de la lengua para estudio histopatológico de hematoxilina-eosina convencional, buscando la presencia de focos de lesiones reaccionales, pre-neoplásicos y neoplásicos. RESULTADOS: Se encontró un total de 58 lesiones macroscópicamente detectables, localizadas principalmente en la zona dorsal-medial de la lengua, de apariencia leucoplásica, de tamaños < a 1 mm hasta 3 mm, y de forma sésil. En el estudio histopatológico, las lesiones de mayor incidencia, en orden decreciente, fueron las hiperqueratosis, la hiperplasia, el carcinoma invasor y la displasia severa o CA in situ. CONCLUSIÓN: El 4-nitroquinolina 1-óxido es capaz de inducir cambios histopatológicos reaccionales, pre-neoplásicos y neoplásicos en el epitelio de la mucosa lingual de ratones CF-1 en forma similar a otros modelos animales ya sea de otras especies o cepa

Chemical and biological analysis of 4-acyloxy-3-nitrocoumarins as trypanocidal agents

Chagas disease is the most widespread contagious tropical disease in Latin America, being an important public health problem. Treatments against this disease are still very ineffective, presenting several side effects. Therefore, the search for alternative therapeutic solutions is urgent. In the present work, we evaluate the trypanocidal activity and the mechanism of action of a select series of synthetic 4-acyloxy-3-nitrocoumarins. All the coumarin derivatives showed moderate trypanocidal activity in trypomastigotes, along with low cytotoxicity. In addition, compound 1 decreased the number of infected Vero cells in an intracellular T. cruzi model. Electron spin resonance and electrochemical studies showed the formation of nitro radical anions. The Fukui index provided additional information to elucidate the proposed reduction mechanism. Furthermore, in vitro radical formation studies demonstrated the potential of these compounds to achieve higher concentrations of intracellular free radicals, proposing oxidative stress as a possible trypanocidal mechanism. Furthermore, no correlation was observed between the diffusion of these compounds, which shows that lipophilicity is not a predominant factor for activity. Elsevier Ltd. All rights reservedThis project was partially supported by the University of Porto and University of Santiago de Compostela. MJM would like to thank Xunta de Galicia (Galician Plan of Research, Innovation and Growth 2011–2015, Plan I2C, ED481B 2014/086–0 and ED481B 2018/007) and Fundação para a Ciência e Tecnologia (CEECIND/02423/2018 and UIDB/00081/2020). FS would like to thank FONDECYT 1190340 and REDES170126, COA would like to thank FONDECYT 1190340, JDM would like to thank FONDECYT 1170126 and ANID/PCI REDES 170126, and MMB would like to thank FONDECYT Postdoctoral 3190449S

Host–Pathogen Interaction Involved in <i>Trypanosoma cruzi</i> Infection

Chagas disease, or American trypanosomiasis, caused by the protozoan parasite Trypanosoma cruzi (T. cruzi) [...