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The protozoan Trypanosoma cruzi ( T. cruzi ) is a well-adapted parasite to mammalian hosts and the pathogen of Chagas disease in humans. As both host and T. cruzi are highly genetically diverse, many variables come into play during infection, making disease outcomes difficult to predict. One important challenge in the field of Chagas disease research is determining the main factors leading to parasite establishment in the chronic stage in some organs, mainly the heart and/or digestive system. Our group previously showed that distinct strains of T. cruzi (JG and Col1.7G2) acquired differential tissue distribution in the chronic stage in dually infected BALB/c mice. To investigate changes in the host triggered by the two distinct T. cruzi strains, we assessed the gene expression profiles of BALB/c mouse hearts infected with either JG, Col1.7G2 or an equivalent mixture of both parasites during the initial phase of infection. This study demonstrates the clear differences in modulation of host gene expression by both parasites. Col1.7G2 strongly activated Th1-polarized immune signature genes, whereas JG caused only minor activation of the host immune response. Moreover, JG strongly reduced the expression of genes encoding ribosomal proteins and mitochondrial proteins related to the electron transport chain. Interestingly, the evaluation of gene expression in mice inoculated with a mixture of the parasites produced expression profiles with both up- and downregulated genes, indicating the coexistence of both parasite strains in the heart during the acute phase. This study suggests that different strains of T. cruzi may be distinguished by their efficiency in activating the immune system, modulating host energy metabolism and reactive oxygen species production and decreasing protein synthesis during early infection, which may be crucial for parasite persistence in specific organs., (Copyright © 2020 Castro, Canesso, Boroni, Chame, Souza, Toledo, Tahara, Pena, Machado, Chiari, Macedo and Franco.)

Chagas disease is a neglected chronic condition that presents high morbidity and mortality burden, with considerable psychological, social, and economic impact. The disease represents a significant public health issue in Brazil, with different regional patterns. This document presents the evidence that resulted in the Brazilian Consensus on Chagas Disease. The objective was to review and standardize strategies for diagnosis, treatment, prevention, and control of Chagas disease in the country, based on the available scientific evidence. The consensus is based on collaboration and contribution of renowned Brazilian experts with vast knowledge and experience on various aspects of the disease. It is the result of close collaboration between the Brazilian Society of Tropical Medicine and the Ministry of Health. This document shall strengthen the development of integrated control measures against Chagas disease in the country, focusing on epidemiology, management, comprehensive care (including families and communities), communication, information, education, and research.

The immune response is crucial for protection against disease; however, immunological imbalances can lead to heart and digestive tract lesions in chagasic patients. Several studies have evaluated the cellular and humoral immune responses in chagasic patients in an attempt to correlate immunological findings with clinical forms of Chagas disease. Moreover, immunoglobulins and cytokines are important for parasitic control and are involved in lesion genesis. Here, cytokine and IgG isotype production were studied, using total epimastigote antigen on sera of chagasic patients with indeterminate (IND, n = 27) and cardiac (CARD, n = 16) forms of the disease. Samples from normal,uninfected individuals (NI, n = 30) were use as controls. The results showed that sera from both IND and CARD patients contained higher levels of Trypanosoma cruzi-specific IgG1 (IgG1) antibodies than sera from NI. No difference in IgG2 production levels was observed between NI, IND and CARD patients, nor was a difference in IL-10 and IFN-gamma production detected in the sera of IND, CARD and NI patients. However, IND patients displayed a positive correlation between IL-10 and IFN-gamma levels in serum, while CARD patients showed no such correlation, indicating an uncontrolled inflammatory response in CARD patients. These findings support the hypothesis that a lack of efficient regulation between IFN-gamma and IL-10 productions in CARD patients may lead to cardiac immunopathology.

The chemical transformations of eremantholide C (1), a trypanocidal sesquiterpene lactone isolated from Lychnophora trichocarpha Spreng., gave five new oxide derivatives: 3'-hydroxyeremantholide C (2), 1'-formyleremantholide C (3), 1'-carboxyeremantholide C (4), 1'-carbomethoxyeremantholide C (5) and sodium 1'-carboxylate of eremantholide C (6). The (1)H and (13)C NMR data of all these derivatives were assigned based on 1D and 2D techniques. The derivatives were evaluated against Y and CL strains of Trypanosoma cruzi. All of them were inactive against the Y strain. Compounds 2 and 5 displayed 100% activity on the CL strain while compounds 4 and 6 were partially active on the CL strain., (Copyright (c) 2007 John Wiley & Sons, Ltd.)

Chagas' disease, caused by Trypanosoma cruzi, has an acute phase characterized by blood-circulating trypomastigotes and amastigote proliferation in several cell types, especially muscle cells. In the chronic phase, around 70% of infected people are asymptomatic (latent form). The remainder develop chagasic cardiomyopathy and/or digestive syndromes. There is evidence for aggravation of the chronic cardiac pathology by endothelin-mediated vasoconstriction. Holtzman rats have proven to be a good model for Chagas' disease acute phase and latent chronic phase. Now, we investigate the effects of prolonged treatment with an endothelin ET(A) receptor antagonist, BSF 461314, during the acute phase on parasitemia, coronary flow, tissue parasitism and the inflammatory process. Using isolated heart in Langendorff's preparation, endothelial dysfunction was observed only in non-treated infected animals. Histoquantitative analyses carried out in heart and diaphragm showed higher tissue parasitism and/or inflammatory process in BSF 461314-treated animals. Our data indicate that endothelin ET(A) receptors contribute to the initial mechanisms of parasite control. Impairment of the endothelium-dependent vasodilatation favors hazardous effects. However, blocking endothelin ET(A) receptors can prevent the latter.

We aim at investigating the role of blood born macrophages on the brain reaction to Trypanosoma cruzi infection in suckling rats. This infection provoked the appearance of numerous ED1(+) cells in the neural parenchyma and increased the amount of meningeal and perivascular ED2(+) macrophages. CD8(+) and NKR(+) cells also occurred. Parenchymal blood vessels showed strong ICAM-1 and decreased occludin immunoreactivities. Selective depletion of peripheral macrophages by clodronate liposomes decreased tissue parasitism, nodular lesions, ICAM-1 upregulation and leukocyte infiltration. Occludin immunoreactivity remained as in uninfected animals. Our results indicate a role for blood-born macrophages in both parasite invasion and brain reaction. Microglia activation cannot be discarded.

In rats, CL-Brener clone caused high mortality, severe acute myocarditis, and myositis that subsided completely in surviving animals. Accordingly, no parasite kDNA could be amplified in several organs after 4 months. The monoclonal JG strain caused null mortality, acute predominantly focal myocarditis, discrete and focal myositis, and a chronic phase with sparse inflammatory foci. Double infection with both Trypanosoma cruzi populations turned mortality very low or null. At the end of the acute phase, the heart exhibited only JG strain kDNA (LSSP-PCR), while skeletal muscles and rectum exhibited only CL-Brener kDNA. Molecular and histopathological findings were accordant. In double infection chronic phase, JG strain remains in heart and appeared in organs previously parasitized by CL-Brener clone. Understanding the virulence and histotropism shifts now described could be important to clarify the variable clinical course and epidemiological peculiarities of Chagas' disease.

The complement regulatory protein (CRP) of Trypanosoma cruzi is a developmentally regulated glycosylphosphatidylinositol (GPI)-anchored membrane protein that protects the parasite from complement-mediated killing, and is an important virulence determinant of the microorganism. CRP binds human complement components C3b and C4b to restrict activation of the complement cascade. Here, we report production of functional, recombinant T. cruzi CRP in mammalian cells and a one-step purification of the recombinant protein. Exchange of the crp DNA sequence encoding the carboxy-terminal GPI signal sequence with the corresponding sequence of decay accelerating factor (DAF) was necessary for recognition, cleavage, and addition of GPI in mammalian cells. CRP production was assessed in two mammalian cell lines with crp-daf gene expression driven by three different transcription control regions: Rous sarcoma virus long terminal repeat, cytomegalovirus (CMV) immediate early gene, and chicken beta-actin promoter/CMV enhancer. We present evidence that CRP produced in transfected Chinese hamster Ovary (CHO) cells was functional and protected the cells from complement-mediated lysis. To facilitate purification of the recombinant protein, a hexahistidyl tag was incorporated at 3(') end of the cDNA upstream of the GPI anchor addition sequence. An additional histidine fusion construct was made that allowed for secretion and recovery of recombinant protein from culture supernatant fluid. Both membrane and secreted forms of the protein were purified in one step by nickel nitrilotriacetic acid. The production and purification of functionally active CRP in a non-infectious expression system will allow for structure and function studies aimed at identifying the active site(s) of this protein.

The search for a colorless, nontoxic and efficient drug to prevent transfusion-associated Chagas' disease (TACD) has been underway unsuccessfully since 1953 when gentian violet was preconized and to date is still being used as the only in vitro trypanocidal agent. The recent findings of aminoquinolone "WR6026" as a trypanocidal agent, led the authors to study the metabolism of red cells stored with this compound, the main objective of which was to define its applicability in TACD control. Ten units of human whole blood collected in CPDA-1 were divided into two equal satellite bags. One had "WR6026" (final concentration 62.5 g/mL) added and the other was used as a control, both were stored at 4 C. At baseline, day 7, 14, 21 and 28, samples were taken for the following measurements: adenosine triphosphate (ATP), hemoglobin, electrolytes (sodium and potassium), gases (pO2 and pCO2) and osmotic fragility. The results of tests and control were analyzed through parametric t-student test. The results were similar in both groups throughout the experiment except for the level of ATP on day 14, which presented significantly higher values in the tests when compared with the controls (p = 0.012). It was concluded that WR6026 does not interfere in the preservation and probably the viability of the erythrocytes also until day 28 of storage. Consequently the authors suggest that WR6026 could emerge as a colorless substitute for gentian violet in the control of TACD in endemic areas.

In the present study, we investigated the role of dogs as experimental models for acute and chronic phases of Chagas' disease, before and after therapeutic treatments. Dogs were infected with Trypanosoma cruzi strains of different susceptibilities to benznidazole (Bz) and treated with the same therapeutic scheme as used for human chagasic. The treatment with Bz was able to prevent death and induced parasitological cure in 62.5% (acute phase) and 38.7% (chronic recent phase) of the tested animals. These results were similar to those reported in clinical trials for treated human patients (cured and uncured) in both phases of the disease. We also showed that parasitologic and serologic tests for monitoring the cure were similar to those obtained for human trials. In addition, Polymerase chain reaction showed the highest sensitivity when compared with hemoculture as an indicator of parasite clearance. In conclusion, the proposed experimental model should be relevant for chemotherapy studies for the control of Chagas' disease.

Early diagnosis of the clinical reactivation of Chagas' disease in human immunodeficiency virus- and Trypanosoma cruzi-coinfected persons is fundamental for a good prognosis. Polymerase chain reaction rapidly and efficiently demonstrated the presence and elimination of T. cruzi in the cerebrospinal fluid of a patient with chagasic meningoencephalitis. Characterization of T. cruzi, directly and indirectly in blood and cerebrospinal fluid samples, demonstrated homogeneity of kinetoplast DNA and the presence of lineage 1 (T. cruzi II) in both parasite populations.