Multi-therapeutic strategy targeting parasite and inflammation-related alterations to improve prognosis of chronic Chagas cardiomyopathy: a hypothesis-based approach*

Chagas disease (CD), caused by infection by the protozoan parasite Trypanosoma cruzi, presents as main clinical manifestation the chronic chagasic cardiomyopathy (CCC). CCC afflicts millions of people, mostly in Latin America, and vaccine and effective therapy are still lacking. Comprehension of the host/parasite interplay in the chronic phase of T. cruzi infection may unveil targets for rational trait-based therapies to improve CCC prognosis. In the present viewpoint, I critically summarise a collection of data, obtained by our network of collaborators and other groups on CCC and preclinical studies on pathogenesis, targeting identification for intervention and the use of drugs with immunomodulatory properties to improve CCC. In the last two decades, models combining mouse lineages and T. cruzi strains allowed replication of crucial clinical, histopathological, and immunological traits of CCC. This condition includes conduction changes (heart rate changes, arrhythmias, atrioventricular blocks, prolongation of the QRS complex and PR and corrected QT intervals), ventricular dysfunction and heart failure, CD8-enriched myocarditis, tissue remodeling and progressive fibrosis, and systemic inflammatory profile, resembling "cytokine storm". Studies on Chagas' heart disease pathogenesis begins to unveil the molecular mechanisms underpinning the inflammation-related cardiac tissue damage, placing IFNγ, TNF and NFκB signaling as upstream regulators of miRNAs and mRNAs associated with critical biological pathways as cell migration, inflammation, tissue remodeling and fibrosis, and mitochondrial dysfunction. Further, data on preclinical trials using hypothesis-based tools, targeting parasite and inflammation-related alterations, opened paths for multi-therapeutic approaches in CCC. Despite the long path taken using experimental CD models replicating relevant aspects of CCC and testing new therapies and therapeutic schemes, these findings may get lost in translation, as conceptual and economical challenges, underpinning the valley of death across preclinical and clinical trials. It is hoped that such difficulties will be overcome in the near future.

Polymorphism in the catalytic subunit of the PI3Kγ gene is associated with Trypanosoma cruzi-induced chronic chagasic cardiomyopathy.

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi. During the chronic phase of disease, while most infected people do not present symptoms, characterizing the asymptomatic form, some patients develop the cardiac form or chronic chagasic cardiomyopathy, which is considered the most severe manifestation of this disease. Considering that the activation of the PI3Kγ signaling pathway is essential for an efficient immune response against T. cruzi infection, we evaluated the PIK3CG C > T (rs1129293) polymorphism in exon 3 of this gene, which encodes the catalytic subunit of PI3Kγ. The PIK3CG CT and TT genotypes were found to be associated with an increased risk of developing the cardiac form of the disease rather than the asymptomatic or digestive forms. In conclusion, the presence of the T allele at single or double doses may differentiate the cardiac from other clinical manifestations of Chagas disease. This finding should help in further studies to evaluate the mechanisms underlying the differential association of PIK3CG in Chagas disease.

IL-10-Dependent and -Independent Mechanisms Are Involved in the Cardiac Pathology Modulation Mediated by Fenofibrate in an Experimental Model of Chagas Heart Disease.

IL-10 is an anti-inflammatory cytokine that plays a significant role in the modulation of the immune response in many pathological conditions, including infectious diseases. Infection with Trypanosoma cruzi (T. cruzi), the etiological agent of Chagas disease, results in an ongoing inflammatory response that may cause heart dysfunction, ultimately leading to heart failure. Given its infectious and inflammatory nature, in this work we analyzed whether the lack of IL-10 hinders the anti-inflammatory effects of fenofibrate, a PPARα ligand, in a murine model of Chagas heart disease (CHD) using IL-10 knockout (IL-10 KO) mice. Our results show fenofibrate was able to restore the abnormal cardiac function displayed by T. cruzi-infected mice lacking IL-10. Treatment with fenofibrate reduced creatine kinase (CK) levels in sera of IL-10 KO mice infected with T. cruzi. Moreover, although fenofibrate could not modulate the inflammatory infiltrates developing in the heart, it was able to reduce the increased collagen deposition in infected IL-10 KO mice. Regarding pro-inflammatory mediators, the most significant finding was the increase in serum IL-17. These were reduced in IL-10 KO mice upon fenofibrate treatment. In agreement with this, the expression of RORγt was reduced. Infection of IL-10 KO mice increased the expression of YmI, FIZZ and Mannose Receptor (tissue healing markers) that remained unchanged upon treatment with fenofibrate. In conclusion, our work emphasizes the role of anti-inflammatory mechanisms to ameliorate heart function in CHD and shows, for the first time, that fenofibrate attains this through IL-10-dependent and -independent mechanisms.

Therapy with Cardiomyocytes Derived from Pluripotent Cells in Chronic Chagasic Cardiomyopathy.

Chagas disease discovered more than a century ago remains an incurable disease. The objective of this work was to investigate the therapeutic potential of cardiomyocytes derived from mouse embryonic stem cells (CM-mESC) in a model of chronic Chagasic cardiomyopathy (CCC). Mouse embryonic stem cells (mESC) were characterized, transduced with luciferase, and submitted to cardiac differentiation. CM-mESC were labeled with superparamagnetic iron oxide particles. To induce CCC, mice were infected with Brazil strain trypomastigotes. At 150 days post-infection (dpi), infected animals were treated with CM-mESC or PBS. Cells were detected by magnetic resonance imaging (MRI) and bioluminescence. Cardiac function was evaluated by MRI and electrocardiogram at 150 and 196 dpi. CCC mice showed significant differences in MRI and ECG parameters compared to non-infected mice. However, no differences were observed in contractile and electrical parameters between cell and PBS injected groups, 45 days after cell transplantation. Cells were detected 24 h after transplantation by MRI. CM-mESC bioluminescence tracking demonstrated over 90% decrease in signal 8 days after treatment. Nevertheless, the Infected + CM-mESC group showed a significant reduction in the percentage of collagen fibers when compared to the Infected + PBS group. In conclusion, CM-mESC therapy was not effective in reversing cardiac functional changes induced by Chagas disease despite some improvement in myocardial fibrosis.

Resonancia magnética cardíaca en la miocardiopatía chagásica crónica. Una herramienta para optimizar el diagnóstico, la estratificación de riesgo y el pronóstico / Cardiac magnetic resonance imaging in chronic chagasic cardiomyopathy. A tool to optimize diagnosis, risk stratification and prognosis

Resumen La enfermedad de Chagas es un problema de salud pública en Latinoamérica, donde afecta a aproximadamente a 6 millones de personas. En Costa Rica se ha descrito la enfermedad desde 1941, con varios reportes de casos confirmados agudos y crónicos. La miocardiopatía chagásica afecta al 30% de los individuos con infección crónica y es la manifestación más grave de la enfermedad, con una morbimortalidad mayor que otras miocardiopatías. La resonancia magnética cardíaca, debido a su capacidad de caracterización tisular permite identificar con alta correlación histopatológica la presencia de fibrosis, edema e inflamación en la miocardiopatía chagásica. Esto ha permitido una mejor comprensión de la compleja fisiopatología de la enfermedad y además permite el diagnóstico diferencial con otras patologías simuladoras como lo es la cardiopatía isquémica. En la MCh la presencia de fibrosis miocárdica predice de manera independiente eventos adversos mayores tales como taquicardia ventricular sostenida y muerte cardiovascular. Debido a lo anterior la resonancia magnética cardíaca es una robusta herramienta capaz de mejorar el diagnóstico, la estratificación de riesgo y el pronóstico de estos pacientes, con miras a mejores y oportunas intervenciones terapéuticas.

Abstract Chagas disease is a public health problem in Latin America, where it affects approximately 6 million people. In Costa Rica the disease has been described since 1941, with several reports of acute and chronic confirmed cases. Chagas cardiomyopathy affects 30% of individuals with chronic infection and is the most serious manifestation of the disease, with a higher morbidity and mortality than other cardiomyopathies. Cardiac magnetic resonance, due to its capacity for tissue characterization, identifies the presence of fibrosis, aedema and inflammation in Chagas cardiomyopathy with high histopathological correlation. This has allowed a better understanding of the complex pathophysiology of the disease and also allows differential diagnosis with other pathologies that can simulate, such as ischemic heart disease. In Chagas cardiomyopathy, the presence of myocardial fibrosis independently predicts major adverse events such as sustained ventricular tachycardia and cardiovascular death. Due to the above, cardiac magnetic resonance is a robust tool capable of improving the diagnosis, risk stratification and prognosis of these patients, with a view to better and timely therapeutic interventions.

Insuficiencia cardíaca en miocardiopatía chagásica crónica

Acorde al último reporte epidemiológico de la Organización Mundial de la Salud del año 2015, en Argentina existen 1,5 millones de personas infectadas por el Trypanosoma cruzi y alrededor de 370.000 pacientes con distintas manifestaciones de la enfermedad de Chagas. El objetivo de esta revisión es analizar una de las manifestaciones clínicas más graves e invalidantes de esta enfermedad: la miocardiopatía chagásica crónica. Esta patología, que presenta una distribución geográfica dispar en la Argentina, comparte varias características comunes con otras formas etiológicas de insuficiencia cardíaca, aunque su epidemiología, presentación clínica y respuesta al tratamiento médico, eléctrico y quirúrgico le otorgan una distinción particular y en muchos casos, poco conocida. Por tal motivo, existe en la comunidad médica, un creciente interés en alcanzar un mayor conocimiento de esta enfermedad a fin de implementar manejos y decisiones terapéuticas, que si bien demostraron beneficio en otras poblaciones de pacientes con insuficiencia cardíaca, aun no han sido adecuadamente avaladas para su aplicación en insuficiencia cardíaca chagásica. Muchas de las indicaciones e intervenciones se basan en experiencia más que evidencia científica. Es por ello que esta revisión es un desafío oportuno para optimizar el tratamiento y pronóstico de esta población.

According to the last epidemiological report of the World Health Organization in 2015, in Argentina there are 1.5 million people infected with Trypanosoma cruzi and around 370,000 patients with different manifestations of Chagas disease. The objective of this review is to analyze one of the most serious and invalidating clinical manifestations of this disease: chronic chagasic myocardiopathy. This pathology, which has a disparate geographical distribution in Argentina, shares several common characteristics with other etiological forms of heart failure, although its epidemiology, clinical presentation and response to medical, electrical and surgical treatment give it a particular distinction and in many cases, little known. For this reason, there is a growing interest in the medical community to achieve greater knowledge of this disease in order to implement management and therapeutic decisions, which although they have shown benefit in other populations of patients with heart failure, have not yet been adequately endorsed. for its application in chagasic heart failure. Many of the indications and interventions are based on experience rather than scientific evidence. That is why this review is a timely challenge to optimize the treatment and prognosis of this population.

De acordo o último relatório epidemiológico da Organização Mundial da Saúde em 2015, na Argentina existem 1,5 milhão de pessoas infectadas pelo Trypanosoma cruzi e cerca de 370.000 pacientes com manifestações diferentes da doença de Chagas. O objetivo desta revisão é analisar uma das manifestações clínicas mais graves e invalidantes dessa doença: miocardiopatia chagásica crônica. Esta condição, que tem uma distribuição geográfica desigual na Argentina, compartilha várias características comuns com outras formas etiológicos de insuficiência cardíaca, embora sua epidemiologia, apresentação clínica e resposta ao tratamento médico, elétrico e cirúrgico dar uma distinção especial e, em muitos casos, pouco conhecido. Portanto, há na comunidade médica, um crescente interesse na obtenção de uma melhor compreensão da doença, a fim de implementar as decisões de manejo e tratamento, que embora benefício mostrou em outras populações de pacientes com insuficiência cardíaca ainda não foram adequadamente apoiados para sua aplicação na insuficiência cardíaca chagásica. Muitas das indicações e intervenções são baseadas na experiência e não na evidência científica. É por isso que esta revisão é um desafio oportuno para otimizar o tratamento e o prognóstico dessa população.

A systematic review of the Trypanosoma cruzi genetic heterogeneity, host immune response and genetic factors as plausible drivers of chronic chagasic cardiomyopathy.

Chagas disease is a complex tropical pathology caused by the kinetoplastid Trypanosoma cruzi. This parasite displays massive genetic diversity and has been classified by international consensus in at least six Discrete Typing Units (DTUs) that are broadly distributed in the American continent. The main clinical manifestation of the disease is the chronic chagasic cardiomyopathy (CCC) that is lethal in the infected individuals. However, one intriguing feature is that only 30-40% of the infected individuals will develop CCC. Some authors have suggested that the immune response, host genetic factors, virulence factors and even the massive genetic heterogeneity of T. cruzi are responsible of this clinical pattern. To date, no conclusive data support the reason why a few percentages of the infected individuals will develop CCC. Therefore, we decided to conduct a systematic review analysing the host genetic factors, immune response, cytokine production, virulence factors and the plausible association of the parasite DTUs and CCC. The epidemiological and clinical implications are herein discussed.

Associação do polimorfismo de ifng +874T/A com a cardiopatia chagásica crônica / Association of ifng +874 T/A polymorphism with chronic chagas' disease

A doença de Chagas é uma zoonose causada pelo parasita hemoflagelado Trypanosoma cruzi. Atualmente afeta cerca de 10 milhões de pessoas nas Américas, e aproximadamente 90 milhões de pessoas se encontram em áreas de risco. A cardiopatia chagásica crônica (CCC) se desenvolve em um terço dos indivíduos infectados e corresponde a uma miocardite crônica fibrosante intensa e os possíveis fatores que podem contribuir para o desenvolvimento desta podem estar relacionados com a carga parasitária, a cepa do parasita, a autoimunidade e fatores genéticos do parasita e do hospedeiro. Citocinas e quimiocinas têm um importante papel no desenvolvimento de uma resposta imune protetora contra o parasita, porém esta pode estar envolvida com o aumento da inflamação encontrada no miocárdio de pacientes com CCC. O principal objetivo deste estudo foi identificar a freqüência dos genótipos e alelos para o SNP no IFNG na posição +874T/A através da técnica de ARMS - PCR, em 102 pacientes soropositivos para o T. cruzi apresentando a CCC, 86 pacientes soropositivos sem cardiopatia aparente e 179 controles soronegativos para T. cruzi. Não há diferença estatística quando pacientes com CCC foram comparados com indivíduos saudáveis, indicando que o polimorfismo para IFNG na posição +874T/A não parece ter influencia na infecção. Contudo, observamos que o genótipo AA foi mais freqüentemente encontrado em pacientes portadores da CCC do que naqueles portadores da forma indeterminada, sugerindo que indivíduos com este genótipo estão mais susceptíveis ao aparecimento de lesões cardíacas e ao adoecimento (p=0,024)...

Chagas disease is a zoonosis caused by the parasite hemoflagellate Trypanosoma cruzi. Currently affects approximately 10 millions people in the Americas, where approximately 90 millions people are at risk areas. The Chronic chagasic cardiomyopathy (CCC) develops in one third of infected individuals and represents a severe chronic myocarditi. Possible factors that may contribute to the development of several cariopathy can be related to parasite load and difference on strains, autoimmunity and the genetics of the parasite and host. Cytokines and chemokinesplay an important role in the development of a protective immune response against the parasite, but it may be involved with increased inflammation found in the myocardium of CCC. The main objective of this study was to identify the frequency of genotypes and alleles for the SNP in the IFNG position +874 T/A by ARMS-PCR technique in 102 patients seropositive for T. cruzi presenting the CCC, 86seropositive patients without apparent heart disease and 179 negative controls for T. cruzi. There was no statistical difference when CCC patients were compared withhealthy subjects, indicating that the polymorphism at the position +874 T/A does not seem to influence the infection. However, we observed that the AA genotype was more frequently found among patients with CCC than in patients without apparent heart disease, suggesting that individuals with this genotype are more susceptible to develop cardiac illness (p=0,024)...

Current and emerging therapeutic options for the treatment of chronic chagasic cardiomyopathy.

Chagas' disease is an endemic disease in Latin America caused by a unicellular parasite (Trypanosoma cruzi) that affects almost 18 million people. This condition involves the heart, causing heart failure, arrhythmias, heart block, thromboembolism, stroke, and sudden death. In this article, we review the current and emerging treatment of Chagas' cardiomyopathy focusing mostly on management of heart failure and arrhythmias. Heart failure therapeutical options including drugs, stem cells and heart transplantation are revised. Antiarrhythmic drugs, catheter ablation, and intracardiac devices are discussed as well. Finally, the evidence for a potential role of specific antiparasitic treatment for the prevention of cardiovascular disease is reviewed.