Efficacy of the Benznidazole+Posaconazole combination therapy in parasitemia reduction: An experimental murine model of acute Chagas

Abstract INTRODUCTION: Benznidazole (BZL) and Nifurtimox (NFX) are the pharmacological treatment for acute phase Chagas Disease (CD); however, therapy resistance and residual mortality development remain important unresolved issues. Posaconazole (POS) has shown a trypanocidal effect in vivo and in vitro. Thus, this study aimed at comparing the T. Cruzi parasitic load-reducing effect of the combination of BZL+POS against that of monotherapy with either, during acute phase CD, in an experimental murine model. METHODS Nineteen Wistar rats were randomly allocated to four groups and inoculated with the trypomastigotes of T. cruzi strain´s JChVcl1. The rats were administered anti-parasites from day 20-29 post-infection. The Pizzi and Brener method was used for parasitemia measurement. Longitudinal data analysis for the continuous outcome of repeated measures was performed using parasitemia as the outcome measured at days 20, 22, 24, 27, and 29 post-infection. RESULTS All four groups had similar parasitic loads (p=0.143) prior to therapy initiation. Among the three treatment groups, the BZL+POS (n=5) group showed the highest mean parasitic load reduction (p=0.000) compared with the control group. Likewise, the BZL+POS group rats showed an earlier therapeutic effect and were the only ones without parasites in their myocardial samples. CONCLUSIONS: Treatment of acute phase CD with BZL+POS was more efficacious at parasitemia and myocardial injury reduction, compared with monotherapy with either.

Factores asociados con la participación de pacientes en ensayos clínicos en cáncer / Some reasons why patients take part in cancer clinical trials Abstract

Resumen Introducción: El desarrollo de ensayos clínicos (ECA) en cáncer requiere fundamentalmente de la participación voluntaria de pacientes; sin embargo, no todos están dispuestos a hacerlo y de esto afecta su desarrollo. Los factores más influyentes identificados en otros estudios sobre la decisión de participar han sido: falta de información sobre el diseño del estudio, métodos de aleatorización, tipos de tratamiento, uso de placebos, toxicidad y efectos adversos asociados. Objetivo: Determinar en una muestra de pacientes enfermos de cáncer la disposición a participar en un ensayo clínico y establecer los factores relacionados con la decisión. Métodos: Se realizó un estudio observacional de corte transversal en una muestra de pacientes enfermos de cáncer que incluyó un análisis de regresión logística teniendo como variable dependiente, si la persona estaría dispuesta a participar en un ensayo clínico y un conjunto de variables explicativas. Resultados: Se entrevistaron 366 pacientes, el 84% manifestó no tener conocimiento sobre los ensayos clínicos, el 63% estuvo dispuesto a participar y el porcentaje restante argumentaron factores para no participar como: el temor, el desconocimiento, los riesgos y la posible afectación a su estado de salud. Los factores que más se asociaron con la disposición a participar en un ECA fueron: conocer los aspectos sobre los ECA sobre riesgos y beneficios, así como los derechos de participar y el consentimiento informado. Conclusiones: Se requieren estudios adicionales que permitan identificar los factores asociados con la participación de pacientes enfermos de cáncer en los ECA. Sin embargo, es necesario realizar estrategias conducentes a mejorar la comunicación y la información hacia los pacientes. © 2017 Instituto Nacional de Cancerología.

Abstract Background: Cancer clinical trials require the voluntary participation of patients for their adequate development. Not all patients wish to do this, thus affecting their development. In other studies, the most important identified reasons in that influence the decision have been lack of information about study design, randomisation methods, and kind of treatment, use of placebos, toxicity, and side effects of the investigational medicinal product. Objective: To evaluate the volition to participate in clinical trials, as well as to establish the reasons associated with this in a sample of patients. Methods: A cross-sectional observational study was conducted on a sample of cancer patients. This included a logistic regression analysis, taking the volition to participate in clinical trials as the dependent variable, along with a group of explanatory variables. Results: A total of 366 patients were interviewed. Although 84% did not know about clinical trials, 63% were willing to participate. The reasons the remaining percentage gave for declining to participate were fear, lack of information about risks and benefits, rights, and informed consent. Conclusion: Additional studies are required to identify the reasons associated with participation in cancer clinical trials. Furthermore, strategies are required for improving the information and communication for patients to take part in clinical trials.

Expresión diferencial entre estadios de Trypanosoma cruzi I en el aislamiento de un paciente con cardiomiopatía chagásica crónica de zona endémica de Santander, Colombia / Differential protein expression in developmental stages of Trypanosoma cruzi I isolated from a patient with chronic chagasic cardiomyopathy

Introducción. Trypanosoma cruzi es el agente causal de la enfermedad de Chagas. Durante la infección en los huéspedes mamíferos, se observan dos formas del parásito: tripomastigotes y amastigotes. En el curso de la diferenciación del parásito cada estadio expresa un patrón de proteínas específicas de fase, las cuales son responsables de sus características morfológicas, bioquímicas y biológicas, que podrían estar determinando un papel importante en la capacidad infecciosa, virulencia y supervivencia del parásito. Objetivo. Analizar la expresión diferencial entre los estadios tripomastigote y amastigote de un aislamiento de T. cruzi I, utilizando la electroforesis en dos dimensiones y la identificación de las proteínas diferencialmente expresadas mediante espectrometría de masas. Materiales y métodos. Se utilizó un clon del aislamiento MHOM/07/338 de T. cruzi I y, mediante electroforesis en dos dimensiones, se compararon los perfiles proteicos de los estadios tripomastigote y amastigote del parásito. Las imágenes se analizaron con el software PDQuest y las proteínas diferencialmente expresadas se identificaron por MALDI TOF o LC MS/MS. Resultados. Los geles bidimensionales mostraron un promedio de 325 manchas proteicas en cada estadio. En los análisis comparativos se detectaron 21 manchas "sobre expresadas" en el estadiotripomastigote y 30, en el estadio amastigote. Se seleccionaron 16 proteínas para identificación por espectrometría de masas y se clasificaron en diferentes categorías funcionales. Conclusiones. Las proteínas exclusivas de T. cruzi relacionadas, principalmente, con metabolismo glucolítico y ensamble del citoesqueleto, fueron las que presentaron una mayor expresión diferencial entre los estadios tripomastigote y amastigote del parásito. Estas proteínas podrían ser utilizadas para el diseño de fármacos.

Introduction. Trypanosoma cruzi is the causative agent of Chagas disease. During infection inmammalian hosts, two main forms of the parasite are observed: trypomastigotes and amastigotes. During differentiation, each stage of the parasite expresses a pattern of proteins specific to each phase-proteins which are responsible for the cell’s morphological, biochemical and biological properties. These properties ultimately govern the infectivity, virulence and survival of the parasite. Objective. A differential expression analysis was conducted to compare trypomastigote and amastigote stages of T. cruzi I isolate, and to identify proteins differentially expressed by means of mass spectrometry. Materials and methods. A T. cruzi clone of the strain MHOM/07/338 was used to analyze the differential expression between trypomastigote stages of a T. cruzi isolate, using two-dimensional electrophoresis and identification of diferentially expressed proteins by mass spectrometry. The protein profiles of the stages of the parasite were obtained by two-dimensional gel electrophoresis and visualized in gels dyed with Coomassie blue. The images were analyzed with PDQuest software and the differential expression of the proteins was identified by MALDI TOF or LC MS/MS. Results. The two-dimensional gels revealed an average of 325 protein spots in each stage. The comparative analyses detected 21 spots that were over expressed in the trypomastigote stage and 30 in the amastigote stage. Sixteen of the over expressed proteins were selected for identification by mass spectrometry and classified in several functional categories. Mass spectrophotometry determined that the proteins were associated mainly with glucolytic metabolism and assembly of the cytoskeleton constituents. Conclusions. The differential expression between trypomastigote and amastigote stages consisted of proteins specific to T. cruzi and are potential targets for the design of treatment drugs.