Instituto Nacional Of Parasitologia

Buenos Aires, Argentina

Instituto Nacional Of Parasitologia

Buenos Aires, Argentina

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Morillo C.A.,Hamilton Health Sciences | Avezum A.,Instituto Dante Pazzanese Of Cardiologia | Sosa-Estani S.,Instituto Nacional Of Parasitologia | Rassi A.,Hospital Do Corao Anis Rassi | And 15 more authors.
New England Journal of Medicine | Year: 2015

BACKGROUND The role of trypanocidal therapy in patients with established Chagas' cardiomyopathy is unproven. METHODS We conducted a prospective, multicenter, randomized study involving 2854 patients with Chagas' cardiomyopathy who received benznidazole or placebo for up to 80 days and were followed for a mean of 5.4 years. The primary outcome in the time-to-event analysis was the first event of any of the components of the composite outcome of death, resuscitated cardiac arrest, sustained ventricular tachycardia, insertion of a pacemaker or implantable cardioverter-defibrillator, cardiac transplantation, new heart failure, stroke, or other thromboembolic event. RESULTS The primary outcome occurred in 394 patients (27.5%) in the benznidazole group and in 414 (29.1%) in the placebo group (hazard ratio, 0.93; 95% confidence interval [CI], 0.81 to 1.07; P = 0.31). At baseline, a polymerase-chain-reaction (PCR) assay was performed on blood samples obtained from 1896 patients; 60.5% had positive results for Trypanosoma cruzi on PCR. The rates of conversion to negative PCR results (PCR conversion) were 66.2% in the benznidazole group and 33.5% in the placebo group at the end of treatment, 55.4% and 35.3%, respectively, at 2 years, and 46.7% and 33.1%, respectively, at 5 years or more (P<0.001 for all comparisons). The effect of treatment on PCR conversion varied according to geographic region: in Brazil, the odds ratio for PCR conversion was 3.03 (95% CI, 2.12 to 4.34) at 2 years and 1.87 (95% CI, 1.33 to 2.63) at 5 or more years; in Colombia and El Salvador, the odds ratio was 1.33 (95% CI, 0.90 to 1.98) at 2 years and 0.96 (95% CI, 0.63 to 1.45) at 5 or more years; and in Argentina and Bolivia, the odds ratio was 2.63 (95% CI, 1.89 to 3.66) at 2 years and 2.79 (95% CI, 1.99 to 3.92) at 5 or more years (P<0.001 for interaction). However, the rates of PCR conversion did not correspond to effects on clinical outcome (P = 0.16 for interaction). CONCLUSIONS Trypanocidal therapy with benznidazole in patients with established Chagas' cardiomyopathy significantly reduced serum parasite detection but did not significantly reduce cardiac clinical deterioration through 5 years of follow-up. (Funded by the Population Health Research Institute and others; number, NCT00123916; Current Controlled Trials number, ISRCTN13967269.). © 2015 Massachusetts Medical Society. All rights reserved.

Dey N.,University of Texas Medical Branch | Sinha M.,UTMB | Gupta S.,University of Texas Medical Branch | Gonzalez M.N.,Instituto Nacional Of Parasitologia | And 4 more authors.
PLoS ONE | Year: 2014

In this study, we have utilized wild-type (WT), ASC-/-, and NLRP3-/- macrophages and inhibition approaches to investigate the mechanisms of inflammasome activation and their role in Trypanosoma cruzi infection. We also probed human macrophages and analyzed published microarray datasets from human fibroblasts, and endothelial and smooth muscle cells for T. cruzi-induced changes in the expression genes included in the RT Profiler Human Inflammasome arrays. T. cruzi infection elicited a subdued and delayed activation of inflammasome-related gene expression and IL-1β production in mQs in comparison to LPS-treated controls. When WT and ASC-/- macrophages were treated with inhibitors of caspase-1, IL-1β, or NADPH oxidase, we found that IL-1β production by caspase-1/ASC inflammasome required reactive oxygen species (ROS) as a secondary signal. Moreover, IL-1β regulated NF-κB signaling of inflammatory cytokine gene expression and, subsequently, intracellular parasite replication in macrophages. NLRP3-/- macrophages, despite an inability to elicit IL-1β activation and inflammatory cytokine gene expression, exhibited a 4-fold decline in intracellular parasites in comparison to that noted in matched WT controls. NLRP3-/- macrophages were not refractory to T. cruzi, and instead exhibited a very high basal level of ROS (>100-fold higher than WT controls) that was maintained after infection in an IL-1β-independent manner and contributed to efficient parasite killing. We conclude that caspase-1/ASC inflammasomes play a significant role in the activation of IL-1β/ROS and NF-κB signaling of cytokine gene expression for T. cruzi control in human and mouse macrophages. However, NLRP3-mediated IL-1β/NFκB activation is dispensable and compensated for by ROS-mediated control of T. cruzi replication and survival in macrophages. © 2014 Dey et al.

Pinazo M.-J.,University of Barcelona | Altclas J.,Headship of Infectology | Serra M.B.,University of Barcelona | Garcia-Otero E.C.,University of Seville | And 15 more authors.
Transplantation Reviews | Year: 2011

The substantial immigration into Spain from endemic areas of Chagas disease such as Latin America has increased the number of potential donors of organs and tissues. In addition, an increasing number of patients with advanced Chagas heart disease may eventually be eligible to receive a heart transplant, a universally accepted therapeutic strategy for the advanced stages of this disease. Therefore, it is necessary to establish protocols for disease management. This document is intended to establish the guidelines to be followed when a potential donor or a tissue or organ recipient is potentially affected by Chagas disease and summarizes the action criteria against the possibility of Chagas disease transmission through the donation of organs, tissues, or hematopoietic stem cells and aims to help professionals working in this field. A single registry of transplants in Trypanosoma cruzi infected donors and/or recipients will provide and disseminate experience in this area, which has shown a low recorded incidence to date. © 2011 Elsevier Inc.

Perez-Mazliah D.,Instituto Nacional Of Parasitologia | Perez-Mazliah D.,UK National Institute for Medical Research | Albareda M.C.,Instituto Nacional Of Parasitologia | Alvarez M.G.,Hospital Interzonal General Of Agudos Eva Peron | And 5 more authors.
Frontiers in Immunology | Year: 2012

Allopurinol is the most popular commercially available xanthine oxidase inhibitor and it is widely used for treatment of symptomatic hyperuricaemia, or gout. Although, several anti-inflammatory actions of allopurinol have been demonstrated in vivo and in vitro, there have been few studies on the action of allopurinol on T cells. In the current study, we have assessed the effect of allopurinol on antigen-specific and mitogen-driven activation and cytokine production in human T cells. Allopurinol markedly decreased the frequency of IFN-γ and IL-2-producing T cells, either after polyclonal or antigen-specific stimulation with Herpes Simplex virus 1, Influenza (Flu) virus, tetanus toxoid and Trypanosoma cruzi-derived antigens. Allopurinol attenuated CD69 upregulation after CD3 and CD28 engagement and significantly reduced the levels of spontaneous and mitogen-induced intracellular reactive oxygen species in T cells. The diminished T cell activation and cytokine production in the presence of allopurinol support a direct action of allopurinol on human T cells, offering a potential pharmacological tool for the management of cell-mediated inflammatory diseases. © 2012 Pérez-Mazliah, Albareda, Alvarez, Lococo, Bertocchi, Petti, ViottiandLaucella.

Cucunuba Z.M.,Instituto Nacional Of Salud | Valencia-Hernandez C.A.,Instituto Nacional Of Salud | Puerta C.J.,Pontifical Xavierian University | Sosa-Estani S.,Instituto Nacional Of Parasitologia | And 29 more authors.
Infectio | Year: 2014

Congenital transmission of Chagas disease has not been extensively studied in Colombia, and there are no standardized processes in the health system regarding the specific diagnosis, treatment and follow-up of this disease. In order to generate recommendations on congenital Chagas disease and Chagas in women of childbearing age in Colombia, a consensus of experts was developed. An extensive literature search through the Medline database was carried out using the MeSH terms: «Chagas disease/congenital», «prevention and control», «diagnosis», «therapeutics» and «pregnancy». Appropriate abstracts were selected and the full texts were analyzed. The relevant information was synthesized, classified, and organized into tables and figures and was presented to a panel of experts, which was composed of 30 professionals from various fields. Based on the Delphi methodology, three rounds of consultation were conducted. The first and second rounds were based on electronic questionnaires that measured the level of consensus of each question among the participants. The third round was based on a face-to-face discussion focusing on those questions without consensus in the previous consultations. The evidence was adapted to national circumstances on a case-by-case basis, and the content the final document was approved. These recommendations are proposed for use in routine medical practice by health professionals in Colombia. © 2013 ACIN. Published by Elsevier España, S.L. All rights reserved.

Garavaglia P.A.,Instituto Nacional Of Parasitologia | Cannata J.J.B.,University of Buenos Aires | Cannata J.J.B.,National University of General San Martín | Ruiz A.M.,Instituto Nacional Of Parasitologia | And 4 more authors.
Molecular and Biochemical Parasitology | Year: 2010

Drugs currently used for treatment of Trypanosoma cruzi infection, the ethiological agent of Chagas' disease, have shown side effects and variable efficiency. With the aim to describe parasite enzymes involved in the mechanisms of action of trypanocidal drugs and since it has been reported that reductases are crucial in their metabolism, we attempted to identify novel NADPH-dependent oxido-reductases from T. cruzi. The percolation of a soluble fraction of epimastigote lysates through a Cibacron Blue-Sepharose column followed by elution by NADPH yielded a predominant protein with an apparent molecular weight of 32. kDa. This protein was identified by MALDI-TOF as an aldo-keto reductase (AKR) and hence denominated TcAKR. TcAKR was mainly localized in the cytosol and was also present in trypomastigote and amastigote lysates. The recombinant TcAKR (rec. TcAKR) showed NADPH-dependent reductase activity with the AKR substrates 4-nitrobenzaldehyde and 2-dihydroxyacetone. The saturation curves for both substrates were consistent with the Michaelis-Menten model. We also tested whether rec. TcAKR may reduce naphthoquinones (NQ), since many of these compounds have displayed important trypanocidal activity. rec. TcAKR reduced o-NQ (1,2-naphthoquinone, 9,10-phenanthrenquinone and β-lapachone) with concomitant generation of free radicals but did not exhibit affinity for p-NQ (5-hydroxy-1,4-naphthoquinone, 2-hydroxy-1,4-naphthoquinone, α-lapachone and menadione). The substrate saturation curve with o-NQ fitted to a sigmoidal curve, suggesting that rec. TcAKR presents a cooperative behavior. In addition, three peaks assigned to monomers, dimers and tetramers were obtained when rec. TcAKR was submitted to a Superose 12 gel chromatography column. TcAKR is the first member of the AKR family described in T. cruzi. Our results indicate that this enzyme may participate in the mechanisms of action of trypanocidal drugs. © 2010 Elsevier B.V.

Ferrero M.R.,Instituto Nacional Of Parasitologia | Soprano L.L.,Instituto Nacional Of Parasitologia | Acosta D.M.,Instituto Nacional Of Parasitologia | Garcia G.A.,Instituto Nacional Of Parasitologia | And 3 more authors.
Acta Tropica | Year: 2014

Sulfation, a post-translational modification which plays a key role in various biological processes, is inhibited by competition with chlorate. In Trypanosoma cruzi, the agent of Chagas' disease, sulfated structures have been described as part of glycolipids and we have reported sulfated high-mannose type oligosaccharides in the C-T domain of the cruzipain (Cz) glycoprotein. However, sulfation pathways have not been described yet in this parasite. Herein, we studied the effect of chlorate treatment on T. cruzi with the aim to gain some knowledge about sulfation metabolism and the role of sulfated molecules in this parasite. In chlorate-treated epimastigotes, immunoblotting with anti-sulfates enriched Cz IgGs (AS-enriched IgGs) showed Cz undersulfation. Accordingly, a Cz mobility shift toward higher isoelectric points was observed in 2D-PAGE probed with anti-Cz antibodies. Ultrastructural membrane abnormalities and a significant decrease of dark lipid reservosomes were shown by electron microscopy and a significant decrease in sulfatide levels was confirmed by TLC/UV-MALDI-TOF-MS analysis. Altogether, these results suggest T. cruzi sulfation occurs via PAPS. Sulfated epitopes in trypomastigote and amastigote forms were evidenced using AS-enriched IgGs by immunoblotting. Their presence on trypomastigotes surface was demonstrated by flow cytometry and IF with Cz/dCz specific antibodies. Interestingly, the percentage of infected cardiac HL-1 cells decreased 40% when using chlorate-treated trypomastigotes, suggesting sulfates are involved in the invasion process. The same effect was observed when cells were pre-incubated with dCz, dC-T or an anti-high mannose receptor (HMR) antibody, suggesting Cz sulfates and HMR are also involved in the infection process by T. cruzi. © 2014 Elsevier B.V.

Galat A.,CEA Saclay Nuclear Research Center | Bua J.,Instituto Nacional Of Parasitologia
Cellular and Molecular Life Sciences | Year: 2010

Cyclosporine A (CsA) is an immunosuppressive cyclic peptide that binds with a high affinity to 18 kDa human cyclophilin-A (hCyPA). CsA and its several natural derivatives have some pharmacological potential in treatment of diverse immune disorders. More than 20 paralogues of CyPA are expressed in the human body while expression levels and functions of numerous ORFs encoding cyclophilin-like sequences remain unknown. Certain derivatives of CsA devoid of immunosuppressive activity may have some potential in treatments of Alzheimer diseases, Hepatitis C and HIV infections, amyotrophic lateral sclerosis, congenital muscular dystrophy, asthma and various parasitic infections. Here, we discuss structural and functional aspects of the human cyclophilins and their interaction with various intra-cellular targets that can be under the control of CsA or its complexes with diverse cyclophilins that are selectively expressed in different cellular compartments. Some molecular aspects of the cyclophilins expressed in parasites invading humans and causing diseases were also analyzed. © Springer Basel AG 2010.

Albareda M.C.,Instituto Nacional Of Parasitologia | Olivera G.C.,Instituto Nacional Of Parasitologia | De Rissio A.M.,Instituto Nacional Of Parasitologia | Postan M.,Instituto Nacional Of Parasitologia
American Journal of Tropical Medicine and Hygiene | Year: 2010

We previously reported that the T cell compartment in chronically Trypanosoma cruzi-infected adult subjects display functional and phenotypic signs of immune senescence. This study aimed to investigate the differentiation and the senescent profile of the overall CD8+ T cell compartment in T. cruzi-infected children at the early stage of the disease. We found a lower percentage of naive (CD27+CD28+CD45RA+) and early antigen-experienced (CD45RA-CD27+CD28+), and higher percentages of late differentiated antigen-experienced (CD45RA -CD27-CD28-) CD8+ T cells in T. cruzi-infected children as compared with age-matched uninfected controls. The expression of the interleukin (IL)-7R is also decreased on naive and on antigen-experienced total CD8+ T cells with various degrees of differentiation. Conversely, the expression of HLA-DR, caspase-3, and CD57 did not vary on the total CD8+ T cell compartment. These findings suggest that the duration of the infection is relevant in the process of immune senescent that this parasite can induce. Copyright © 2010 by The American Society of Tropical Medicine and Hygiene.

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