Exercise Training Reduces Inflammation and Fibrosis and Preserves Myocardial Function and Perfusion in a Model of Chronic Chagas Cardiomyopathy. / Treinamento Físico Reduz a Inflamação e a Fibrose e Preserva a Função e a Perfusão Miocárdica em um Modelo de Cardiomiopatia Chagásica Crônica.

BACKGROUND: Chronic Chagas cardiomyopathy (CCC) is caused by an inflammatory process induced by Trypanosoma cruzi, which leads to myocarditis with reactive and reparative fibrosis. CCC progresses with myocardial perfusion abnormalities and histopathological events that affect cardiorespiratory fitness (CRF). OBJECTIVES: We evaluated the effects of aerobic physical training (APT) on myocardial perfusion and on morphological and functional impairments related with inflammation and fibrosis in Syrian hamsters with CCC. As a secondary objective, we analyzed the cross-sectional areas of the skeletal muscle. METHODS: Hamsters with CCC and their respective controls were divided into four groups: CCC sedentary, CCC-APT, sedentary control and APT control. Seven months after infection, the animals underwent echocardiography, myocardial perfusion scintigraphy and cardiopulmonary exercise testing. Moderate-intensity APT was performed for fifty minutes, five times a week, for eight weeks. Subsequently, the animals were reassessed. Histopathological analysis was conducted after the above-mentioned procedures. The level of significance was set at 5% in all analyses (p<0.05). RESULTS: CCC sedentary animals presented worse myocardial perfusion defects (MPD) over time, reduced left ventricle ejection fraction (LVEF) and showed more inflammation and fibrosis when compared to other groups (mixed ANOVA analysis). Conversely, APT was able to mitigate the progression of MPD, ameliorate inflammation and fibrosis and improve CRF efficiency in CCC-APT animals. CONCLUSIONS: Our study demonstrated that APT ameliorated cardiac dysfunction, MPD, and reduced inflammation and fibrosis in CCC hamster models. Additionally, CCC-SED animals presented skeletal muscle atrophy while CCC-APT animals showed preserved skeletal muscle CSA. Understanding APT's effects on CCC's pathophysiological dimensions is crucial for future research and therapeutic interventions.

FUNDAMENTO: A Cardiomiopatia Chagásica Crônica (CCC) é causada por um processo inflamatório induzido pelo Trypanosoma cruzi, que leva à miocardite com fibrose reativa e reparativa. A CCC progride com alterações de perfusão miocárdica e eventos histopatológicos que afetam a Aptidão Cardiorrespiratória (ACR). OBJETIVOS: Avaliamos os efeitos do Treinamento Físico Aeróbico (TFA) na perfusão miocárdica e nos comprometimentos morfológicos e funcionais relacionados à inflamação e fibrose em hamsters sírios com CCC. Como objetivo secundário, analisamos as áreas de secção transversa do músculo esquelético. MÉTODOS: Hamsters com CCC e seus respectivos controles foram divididos em quatro grupos: CCC sedentário, CCC-TFA, controle sedentário e controle TFA. Sete meses após a infecção, os animais foram submetidos à ecocardiografia, à cintilografia de perfusão miocárdica e ao teste de esforço cardiopulmonar. TFA de intensidade moderada foi realizado durante cinquenta minutos, cinco vezes por semana, por oito semanas. Posteriormente, os animais foram reavaliados. A análise histopatológica foi realizada após os procedimentos acima mencionados. O nível de significância foi estabelecido em 5% em todas as análises (p<0,05). RESULTADOS: Animais com CCC sedentários apresentaram piores Defeitos de Perfusão Miocárdica (DPM) ao longo do tempo, Fração de Ejeção do Ventrículo Esquerdo (FEVE) reduzida, e apresentaram mais inflamação e fibrose quando comparados aos demais grupos (análise ANOVA mista). Por outro lado, o TFA foi capaz de mitigar a progressão do DPM, atenuar a inflamação e a fibrose e melhorar a eficiência da ACR em animais CCC-TFA. CONCLUSÃO: Nosso estudo demonstrou que o TFA melhorou a disfunção cardíaca, DPM e reduziu a inflamação e a fibrose em modelos de hamster com CCC. Além disso, os animais CCC-SED apresentaram atrofia do músculo esquelético, enquanto os animais CCC-TFA apresentaram a AST do músculo esquelético preservada. Compreender os efeitos da TFA nas dimensões fisiopatológicas da CCC é crucial para futuras pesquisas e intervenções terapêuticas.

Vitamin D treatment distinctly modulates cytokine production by peripheral blood mononuclear cells among patients with chronic cardiac and indeterminate clinical forms of Chagas disease.

INTRODUCTION: Chagas disease is caused by the protozoan Trypanosoma cruzi and is clinically divided into acute and chronic phases. Chronic Chagas cardiomyopathy is the most studied manifestation of the disease. Vitamin D deficiency has been suggested as a risk factor for cardiovascular disease. No studies demonstrate the action of this hormone in the cells of patients with chronic Chagas heart disease. OBJECTIVE: To evaluate the in vitro immunomodulatory effect of vitamin D on peripheral blood mononuclear cells of patients with the different chronic clinical forms of Chagas disease. Evaluating vitamin D's in vitro effect on blood cells by producing cytokines. METHODS: Thirteen patients of the undetermined form (IND), 13 of the mild cardiac form (CARD1) and 14 of the severe cardiac form (CARD2) of Chagas disease, and 12 with idiopathic heart disease (CARDid) were included. The cells obtained from peripheral blood were treated in vitro with vitamin D (1 × 10-7 M) for 24 h and cytokines were dosed in the culture supernatant. RESULTS: Although it was not possible to demonstrate statistically significant differences between the groups studied, our data showed that the cells treated with vitamin D modify (p < .05) the production of interferon-γ (IFN-γ) (decrease in IND), tumor necrosis factor-α (TNF-α) (decreased in CARD1 and CARDid), interleukin (IL)-6 (increased in all groups), and IL-10 (decreased in CARD1, CARD2, and CARDid) when compared to untreated cells. CONCLUSION: In vitro treatment with vitamin D distinctly modulated the production of cytokines by mononuclear cells of peripheral blood among patients with chronic and indeterminate cardiac clinical forms of Chagas disease.

Sacubitril/Valsartan Versus Enalapril in Chronic Chagas Cardiomyopathy: Rationale and Design of the PARACHUTE-HF Trial.

Chronic Chagas cardiomyopathy (CCC) has unique pathogenic and clinical features with worse prognosis than other causes of heart failure (HF), despite the fact that patients with CCC are often younger and have fewer comorbidities. Patients with CCC were not adequately represented in any of the landmark HF studies that support current treatment guidelines. PARACHUTE-HF (Prevention And Reduction of Adverse outcomes in Chagasic Heart failUre Trial Evaluation) is an active-controlled, randomized, phase IV trial designed to evaluate the effect of sacubitril/valsartan 200 mg twice daily vs enalapril 10 mg twice daily added to standard of care treatment for HF. The study aims to enroll approximately 900 patients with CCC and reduced ejection fraction at around 100 sites in Latin America. The primary outcome is a hierarchical composite of time from randomization to cardiovascular death, first HF hospitalization, or relative change from baseline to week 12 in NT-proBNP levels. PARACHUTE-HF will provide new data on the treatment of this high-risk population. (Efficacy and Safety of Sacubitril/Valsartan Compared With Enalapril on Morbidity, Mortality, and NT-proBNP Change in Patients With CCC [PARACHUTE-HF]; NCT04023227).

The effects of inflammation on connexin 43 in chronic Chagas disease cardiomyopathy.

Background: Cardiac arrhythmias are the main cause of sudden death due to Chronic Chagasic Cardiomyopathy (CCC). Here we investigated alterations in connexin 43 (Cx43) expression and phosphorylation in cardiomyocytes as well as associations with cardiac arrhythmias in CCC. Methods: C57Bl/6 mice infected with Trypanosoma cruzi underwent cardiac evaluations at 6 and 12 months after infection via treadmill testing and EKG. Histopathology, cytokine gene expression, and distribution of total Cx43 and its phosphorylated forms Cx43S368 and Cx43S325/328/330 were investigated. Human heart samples obtained from subjects with CCC were submitted to immunofluorescence analysis. In vitro simulation of a pro-inflammatory microenvironment (IL-1ß, TNF, and IFN-γ) was performed in H9c2 cells and iPSC-derived cardiomyocytes to evaluate Cx43 distribution, action potential duration, and Lucifer Yellow dye transfer. Results: Mice chronically infected with T. cruzi exhibited impaired cardiac function associated with increased inflammation, fibrosis and upregulated IL-1ß, TNF, and IFN-γ gene expression. Confocal microscopy revealed altered total Cx43, Cx43S368 and Cx43S325/328/330 localization and phosphorylation patterns in CCC, with dispersed staining outside the intercalated disc areas, i.e., in lateral membranes and the cytoplasm. Reduced co-localization of total Cx43 and N-cadherin was observed in the intercalated discs of CCC mouse hearts compared to controls. Similar results were obtained in human CCC heart samples, which showed Cx43 distribution outside the intercalated discs. Stimulation of human iPSC-derived cardiomyocytes or H9c2 cells with IL-1ß, TNF, and IFN-γ induced alterations in Cx43 localization, reduced action potential duration and dye transfer between adjacent cells. Conclusion: Heart inflammation in CCC affects the distribution and phosphorylation pattern of Cx43, which may contribute to the generation of conduction disturbances in Chagas disease.

Predictors of Appropriate Therapies and Death in Patients with Implantable Cardioverter-Defibrillator and Chronic Chagas Heart Disease. / Preditores de Terapias Apropriadas e Óbito em Pacientes com Cardiodesfibrilador Implantável e Cardiopatia Chagásica Crônica.

BACKGROUND: There are few retrospective and prospective studies on implantable cardioverter-defibrillators (ICD) in primary and secondary prevention of sudden death in chronic Chagas heart disease (CCHD). OBJECTIVES: To describe the long-term evolution of patients with CCHD and ICD and to identify and analyze predictors of mortality and appropriate device therapy in this population. METHODS: This was a historical prospective study with 117 patients with ICD and CCHD. Devices were implanted from January 2003 to December 2021. Predictors of appropriate therapies and long-term mortality were identified and analyzed. The level of statistical significance was p < 0.05. RESULTS: Patients (n = 117) had a median follow-up of 61 months (25 to 121 months); they were predominantly male (74%), with a median age of 55 years (48 to 64 years). There were 43.6% appropriate shocks, 26.5% antitachycardia pacing (ATP), and 51% appropriate therapies. During follow-up, 46 patients (39.7%) died. Mortality was 6.2% person-years (95% confidence interval [CI]: 4.6 to 8.3), with 2 sudden deaths during follow-up. Secondary prevention (hazard ratio [HR] 2.1; 95% CI: 1.1 to 4.3; p = 0.029) and ejection fraction less than 30% (HR 1.8; 95% CI: 1.1 to 3.1; p < 0.05) were predictors of appropriate therapies. Intermediate Rassi score showed a strong association with the occurrence of ATP alone (p = 0.015). Functional class IV (p = 0.007), left ventricular ejection fraction < 30 (p = 0.010), and age above 75 years (p = 0.042) were predictors of total mortality. CONCLUSION: ICDs in CCHD showed a high incidence of appropriate activation, especially in patients with secondary prevention, low left ventricular ejection fraction, and intermediate Rassi score. Patients with congestive heart failure, elevated functional class, and age over 75 years showed elevated mortality. Survival function of patients with implantable cardioverter-defibrillators and chronic Chagas heart disease. A - According to New York Heart Association functional class; B - According to left ventricular ejection fraction; C - According to Rassi score. D - According to age. CCHD: chronic Chagas heart disease; HR: hazard ratio; ICD: implantable cardioverter-defibrillator.

Impact of cardiac structure and function on exercise intolerance in Chagas cardiomyopathy: Insights from CPET and echocardiography.

INTRODUCTION: Chronic Chagas cardiomyopathy (CCC), the most severe clinical condition of Chagas disease, often leads to a reduction in functional capacity and the appearance of symptoms such as fatigue and dyspnea on exertion. However, its determinant factors remain unclear. We aimed to evaluate the peak oxygen consumption (VO2peak) in patients with CCC and identify its determining factors. METHODS: An observational study with 97 CCC patients was conducted. Patients underwent clinical examination, cardiopulmonary exercise test (CPET), and echocardiography as part of the standard clinical evaluation. Multivariate linear regression was used to identify independent clinical and echocardiographic predictors of VO2peak and percentage of predicted VO2. RESULTS: Mean age of study patients was 55.9 ± 13.4 years, median left ventricle ejection fraction (LVEF) was 40 (26-61.5) % and median VO2peak was 16.1 (12.1-20.8) ml/Kg/min. 36 patients presented preserved LVEF and 61 presented reduced LVEF. There were significant differences in almost all CPET variables (p < 0.05) between these two groups. VO2peak was associated with age, male sex, NYHA functional class, LVEF, left atrium diameter, LV diastolic diameter, E wave, LV mass index, and pulmonary artery systolic pressure (PASP). Age, male sex, LVEF, and E wave remained independently associated with VO2peak in the multivariate analysis (R2 = 0.69), furthermore, only LVEF and E wave were associated with the predicted VO2 percentage (R2 = 0.53). CONCLUSION: In patients with CCC, disease severity, male sex, LV systolic and diastolic function influence the functional capacity.

Identification of Chagas disease biomarkers using untargeted metabolomics.

Untargeted metabolomic analysis is a powerful tool used for the discovery of novel biomarkers. Chagas disease (CD), caused by Trypanosoma cruzi, is a neglected tropical disease that affects 6-7 million people with approximately 30% developing cardiac manifestations. The most significant clinical challenge lies in its long latency period after acute infection, and the lack of surrogate markers to predict disease progression or cure. In this cross-sectional study, we analyzed sera from 120 individuals divided into four groups: 31 indeterminate CD, 41 chronic chagasic cardiomyopathy (CCC), 18 Latin Americans with other cardiomyopathies and 30 healthy volunteers. Using a high-throughput panel of 986 metabolites, we identified three distinct profiles among individuals with cardiomyopathy, indeterminate CD and healthy volunteers. After a more stringent analysis, we identified some potential biomarkers. Among peptides, phenylacetylglutamine and fibrinopeptide B (1-13) exhibited an increasing trend from controls to ICD and CCC. Conversely, reduced levels of bilirubin and biliverdin alongside elevated urobilin correlated with disease progression. Finally, elevated levels of cystathionine, phenol glucuronide and vanillactate among amino acids distinguished CCC individuals from ICD and controls. Our novel exploratory study using metabolomics identified potential biomarker candidates, either alone or in combination that if confirmed, can be translated into clinical practice.

Absolute Lymphocyte Count: a Predictor of Positive Serum PCR for Trypanosoma cruzi in Patients with Chagas Disease Undergoing Heart Transplantation. / Contagem Absoluta de Linfócitos: um Preditor de PCR Sérica Positiva para o Trypanosoma cruzi em Pacientes com Chagas Submetidos ao Transplante Cardíaco.

BACKGROUND: It is unknown whether lymphopenia is a risk factor for the reactivation of Chagas disease in heart transplantation (HTx), as recently described in the reactivation of cytomegalovirus in transplant patients. OBJECTIVE: To evaluate whether lymphopenia in the perioperative period of heart transplantation is related to early Trypanosoma cruzi parasitemia. METHODS: This observational, retrospective study analyzed a sample from January 2014 to January 2023). Parasitemia was evaluated in the first 3 months after HTx using serum polymerase chain reaction (PCR) and compared with the total lymphocyte count in the perioperative period of HTx using receiver operating characteristic curves. Baseline characteristics were compared with PCR for Chagas using independent Cox proportional hazards models. A significance level of 5% was adopted. RESULTS: The sample (n = 35) had a mean age of 52.5 ± 8.1 years, and 22 patients (62.8%) had positive PCR for Chagas. The mean lowest lymphocyte values in the first 14 days after HTx were 398 ± 189 and 755 ± 303 cells/mm3 in patients with and without parasitemia, respectively, within 3 months after HTx (area under the curve = 0.857; 95% confidence interval: 0.996 to 0.718, sensitivity and specificity of 83.3% and 86.4%). A cutoff value of less than 550 lymphocytes/mm3 was determined as a risk factor for the presence of parasitemia. Patients with lymphocytes < 550 units/mm3 in the first 14 days after HTx presented positive PCR in 80% of cases. For every increase of 100 lymphocytes/mm3, the risk of PCR positivity was reduced by 26% (hazard rate ratio = 0.74; 95% confidence interval: 0.59 to 0.93, p = 0.009). CONCLUSION: There was an association between lymphopenia in the perioperative period of HTx and early T. cruzi parasitemia detected by PCR.

FUNDAMENTO: É desconhecido se a linfopenia é fator de risco para a reativação da doença de Chagas no transplante cardíaco (TxC), como recentemente descrito na reativação de citomegalovírus em pacientes transplantados. OBJETIVO: Avaliar se a linfopenia no perioperatório do TxC está relacionada à parasitemia precoce pelo Trypanosoma cruzi. MÉTODOS: Amostra analisada (janeiro de 2014 a janeiro de 2023) em estudo observacional e retrospectivo. A parasitemia foi avaliada nos primeiros 3 meses após o TxC por meio da reação em cadeia da polimerase sérica (PCR) e comparada com a contagem total de linfócitos no perioperatório do TxC por curvas ROC. Comparadas características de base com a PCR Chagas por modelos de risco proporcionais de Cox independentes. Nível de significância adotado de 5%. RESULTADOS: Amostra (n = 35) apresentou idade média de 52,5 ± 8,1 anos e PCR Chagas positiva em 22 pacientes (62,8%). As médias dos menores valores de linfócitos nos primeiros 14 dias do TxC foram 398 ± 189 e 755 ± 303 células/mm3 em pacientes com e sem parasitemia nos 3 meses após o TxC, respectivamente (área sob a curva = 0,857; intervalo de confiança de 95%: 0,996 a 0,718, sensibilidade e especificidade de 83,3% e 86,4%). Determinado valor de corte inferior a 550 linfócitos/mm3 como fator de risco para presença de parasitemia. Pacientes com linfócitos < 550 unidades/mm3 nos primeiros 14 dias do pós-TxC apresentaram PCR positiva em 80% dos casos. Para cada aumento de 100 linfócitos/mm3, o risco de positividade da PCR é reduzido em 26% (razão de riscos = 0,74; intervalo de confiança de 95%: 0,59 a 0,93, p = 0,009). CONCLUSÃO: Houve associação entre a linfopenia no perioperatório do TxC com a parasitemia precoce pelo T. cruzi detectada por PCR.

Association between positive serology for COVID-19 and chagas cardiomyopathy progression: The SaMi-Trop project.

BACKGROUND: Chagas Disease (CD) can cause Chagas cardiomyopathy. The new coronavirus disease (COVID-19) also affects the cardiovascular system and may worsen Chagas cardiomyopathy. However, the cardiac evolution of patients with CD infected by COVID-19 is not known. Thus, the objective of this study is to assess, within one year, whether there was cardiac progression after COVID-19 in CD. METHODS: Longitudinal study with CD patients. The outcome was cardiac progression, defined as the appearance of new major changes in the current ECG compared to the previous ECG considered from the comparison of electrocardiograms (ECGs) performed with an interval of one year. Positive Anti-SARS-CoV2 Serology was the independent variable of interest. For each analysis, a final multiple model was constructed, adjusted for sociodemographic, clinical, and pandemic-related characteristics. RESULTS: Of the 404 individuals included, 22.8 % had positive serology for COVID-19 and 10.9 % had cardiac progression. In the final model, positive serology for COVID-19 was the only factor associated with cardiac progression in the group as a whole (OR = 2.65; 95 % CI = 1.27-5.53) and for new-onset cardiomyopathy in the group with normal previous ECG (OR = 3.50; 95 % CI = 1.21-10.13). CONCLUSION: Our study shows an association between COVID-19 and progression of Chagas cardiomyopathy, evaluated by repeated ECGs, suggesting that COVID-19 accelerated the natural history of CD.

Pirfenidone Prevents Heart Fibrosis during Chronic Chagas Disease Cardiomyopathy.

Cardiac fibrosis is a severe outcome of Chagas disease (CD), caused by the protozoan Trypanosoma cruzi. Clinical evidence revealed a correlation between fibrosis levels with impaired cardiac performance in CD patients. Therefore, we sought to analyze the effect of inhibitors of TGF-ß (pirfenidone), p38-MAPK (losmapimod) and c-Jun (SP600125) on the modulation of collagen deposition in cardiac fibroblasts (CF) and in vivo models of T. cruzi chronic infection. Sirius Red/Fast Green dye was used to quantify both collagen expression and total protein amount, assessing cytotoxicity. The compounds were also used to treat C57/Bl6 mice chronically infected with T. cruzi, Brazil strain. We identified an anti-fibrotic effect in vitro for pirfenidone (TGF-ß inhibitor, IC50 114.3 µM), losmapimod (p38 inhibitor, IC50 17.6 µM) and SP600125 (c-Jun inhibitor, IC50 3.9 µM). This effect was independent of CF proliferation since these compounds do not affect T. cruzi-induced host cell multiplication as measured by BrdU incorporation. Assays of chronic infection of mice with T. cruzi have shown a reduction in heart collagen by pirfenidone. These results propose a novel approach to fibrosis therapy in CD, with the prospect of repurposing pirfenidone to prevent the onset of ECM accumulation in the hearts of the patients.

The mitochondrial uncoupler 2,4-dinitrophenol modulates inflammatory and oxidative responses in Trypanosoma cruzi-induced acute myocarditis in mice.

By uncoupling oxidative phosphorylation, 2,4-dinitrophenol (DNP) attenuates reactive oxygen species (ROS) biosynthesis, which are known to aggravate infectious myocarditis in Chagas disease. Thus, the impact of DNP-based chemotherapy on Trypanosoma cruzi-induced acute myocarditis was investigated. C56BL/6 mice uninfected and infected untreated and treated daily with 100 mg/kg benznidazole (Bz, reference drug), 5 and 10 mg/kg DNP by gavage for 11 days after confirmation of T. cruzi infection were investigated. Twenty-four hours ​after the last treatment, the animals were euthanized and the heart was collected for microstructural, immunological and biochemical analyses. T. cruzi inoculation induced systemic inflammation (e.g., cytokines and anti-T. cruzi IgG upregulation), cardiac infection (T. cruzi DNA), oxidative stress, inflammatory infiltrate and microstructural myocardial damage in untreated mice. DNP treatment aggravated heart infection and microstructural damage, which were markedly attenuated by Bz. DNP (10 mg/kg) was also effective in attenuating ROS (total ROS, H2O2, and O2-), nitric oxide (NO), lipid (malondialdehyde - MDA) and protein (protein carbonyl - PCn) oxidation, TNF, IFN-γ, IL-10, and MCP-1/CCL2, anti-T. cruzi IgG, cardiac troponin I levels, as well as inflammatory infiltrate and cardiac damage in T. cruzi-infected mice. Our findings indicate that DNP aggravated heart infection and microstructural cardiomyocytes damage in infected mice. These responses were related to the antioxidant and anti-inflammatory properties of DNP, which favors infection by weakening the pro-oxidant and pro-inflammatory protective mechanisms of the infected host. Conversely, Bz-induced cardioprotective effects combined effective anti-inflammatory and antiparasitic responses, which protect against heart infection, oxidative stress, and microstructural damage in Chagas disease.

Mortality risk score for patients with Chagas cardiomyopathy and pacemaker.

BACKGROUND: Prognosis of Chronic Chagasic Cardiomyopathy (CCC) patients depends on functional and clinical factors. Bradyarrhythmia requiring pacemaker is a common complication. Prognosis of these patients is poorly studied, and mortality risk factors are unknown. We aimed to identify predictors of death and to define a risk score for mortality in a large cohort of CCC patients with pacemaker. METHODS: It was an observational, unicentric and prospective study. The endpoint was all-cause mortality. Cox regression was used to identify predictors of death and to define a risk score. Bootstrapping method was used to internal score validation. RESULTS: We included 555 patients and after a mean follow-up of 3.7±1.5 years, 100 (18%) deaths occurred. Predictors of death were: right ventricular dysfunction (HR [hazard ratio] 2.24; 95%CI 1.41-3.53; P = 0.001); heart failure class III or IV (HR 2.16; 95% confidence interval [95%CI] 1.16-4.00; P = 0.014); renal disease (HR 2.14; 95%CI 1.24-3.68; P = 0.006); left ventricular end-systolic diameter > 44mm (HR 1.97; 95%CI 1.26-3.05; P = 0.003); atrial fibrillation (HR 1.94; 95%CI 1.25-2.99; P = 0.003) and cardiomegaly on X-ray (HR 1.87; 95%CI 1.10-3.17; P = 0.020). The score identified patients with: low (0-20 points), intermediate (21-30 points) and high risk (>31points). The optimism-corrected C-statistic of the predictive model was 0.751 (95% CI 0.696-0.806). Internal validation with bootstrapping revealed a calibration slope of 0.946 (95% CI 0.920-0.961), reflecting a small degree of over-optimism and C-statistic of 0.746 (95% CI 0.692-0.785). CONCLUSIONS: This study identified predictors of mortality in CCC patients with pacemaker defining a simple, validated and specific risk score.

The usefulness of patient-reported outcome measures in decision making in Chagas cardiomyopathy: a scoping review.

Chagas cardiomyopathy (ChC) presents many biopsychosocial complexities, highlighting the need to have patient self-report questions. This study demonstrates the scope of the use of patient-reported outcome measures (PROMs) in patients with ChC and highlights the main research gaps. This is a scoping review and the search strategy was performed in the Online Medical Literature Analysis and Retrieval System (MEDLINE), Excerpta Medica database (EMBASE), Accumulated Index of Nursing and Allied Health Literature (CINAHL), Cochrane Central, Latin American Literature and Caribbean in Health Sciences (LILACS) and Diagnostic Test Accuracy (DITA). The search identified 4484 studies and 20 studies met the inclusion criteria. The Short-Form of 36 items (SF-36) had potential prognostic value and the ability to identify systolic dysfunction. The Human Activity Profile was able to screen for functional impairment, and the New York Heart Association showed potential prognostic value. The SF-36 and Minnesota Living with Heart Failure Questionnaire were responsive to interventions. The pharmaceutical care affected adherence to treatment as assessed by the Morisky score and also for SF-36. Despite the increased use of PROMs, there are still a large number of gaps in the literature, and further studies using PROMs are needed.

Identification of host antioxidant effectors as thioridazine targets: Impact on cardiomyocytes infection and Trypanosoma cruzi-induced acute myocarditis.

Phenothiazines inhibit antioxidant enzymes in trypanosomatids. However, potential interferences with host cell antioxidant defenses are central concerns in using these drugs to treat Trypanosoma cruzi-induced infectious myocarditis. Thus, the interaction of thioridazine (TDZ) with T. cruzi and cardiomyocytes antioxidant enzymes, and its impact on cardiomyocytes and cardiac infection was investigated in vitro and in vivo. Cardiomyocytes and trypomastigotes in culture, and mice treated with TDZ and benznidazole (Bz, reference antiparasitic drug) were submitted to microstructural, biochemical and molecular analyses. TDZ was more cytotoxic and less selective against T. cruzi than Bz in vitro. TDZ-pretreated cardiomyocytes developed increased infection rate, reactive oxygen species (ROS) production, lipid and protein oxidation; similar catalase (CAT) and superoxide dismutase (SOD) activity, and reduced glutathione's (peroxidase - GPx, S-transferase - GST, and reductase - GR) activity than infected untreated cells. TDZ attenuated trypanothione reductase activity in T. cruzi, and protein antioxidant capacity in cardiomyocytes, making these cells more susceptible to H2O2-based oxidative challenge. In vivo, TDZ potentiated heart parasitism, total ROS production, myocarditis, lipid and protein oxidation; as well as reduced GPx, GR, and GST activities compared to untreated mice. Benznidazole decreased heart parasitism, total ROS production, heart inflammation, lipid and protein oxidation in T. cruzi-infected mice. Our findings indicate that TDZ simultaneously interact with enzymatic antioxidant targets in cardiomyocytes and T. cruzi, potentiating the infection by inducing antioxidant fragility and increasing cardiomyocytes and heart susceptibility to parasitism, inflammation and oxidative damage.

Preclinical evaluation of combined therapy with amiodarone and low-dose benznidazole in a mouse model of chronic Trypanosoma cruzi infection.

Chagasic chronic cardiomyopathy (CCC) is the primary clinical manifestation of Chagas disease (CD), caused by Trypanosoma cruzi. Current therapeutic options for CD are limited to benznidazole (Bz) and nifurtimox. Amiodarone (AMD) has emerged as most effective drug for treating the arrhythmic form of CCC. To address the effects of Bz and AMD we used a preclinical model of CCC. Female C57BL/6 mice were infected with T. cruzi and subjected to oral treatment for 30 consecutive days, either as monotherapy or in combination. AMD in monotherapy decreased the prolonged QTc interval, the incidence of atrioventricular conduction disorders and cardiac hypertrophy. However, AMD monotherapy did not impact parasitemia, parasite load, TNF concentration and production of reactive oxygen species (ROS) in cardiac tissue. Alike Bz therapy, the combination of Bz and AMD (Bz/AMD), improved cardiac electric abnormalities detected T. cruzi-infected mice such as decrease in heart rates, enlargement of PR and QTc intervals and increased incidence of atrioventricular block and sinus arrhythmia. Further, Bz/AMD therapy ameliorated the ventricular function and reduced parasite burden in the cardiac tissue and parasitemia to a degree comparable to Bz monotherapy. Importantly, Bz/AMD treatment efficiently reduced TNF concentration in the cardiac tissue and plasma and had beneficial effects on immunological abnormalities. Moreover, in the cardiac tissue Bz/AMD therapy reduced fibronectin and collagen deposition, mitochondrial damage and production of ROS, and improved sarcomeric and gap junction integrity. Our study underlines the potential of the Bz/AMD therapy, as we have shown that combination increased efficacy in the treatment of CCC.

Signatures of CD4+ T and B cells are associated with distinct stages of chronic chagasic cardiomyopathy.

Introduction: Chagas disease is a neglected parasitic disease caused by Trypanosoma cruzi. While most patients are asymptomatic, around 30% develop Chronic Chagasic Cardiomyopathy (CCC). Methods: Here, we employed high-dimensional flow cytometry to analyze CD4+ T and B cell compartments in patients during the chronic phase of Chagas disease, presenting the asymptomatic and mild or moderate/severe cardiac clinical forms. Results: Effector CD27-CD4+ T cells were expanded in both CCC groups, and only mild CCC patients showed higher frequencies of effector memory and T follicular helper (Tfh) cells than healthy donors (CTL) and asymptomatic patients. Unsupervised analysis confirmed these findings and further revealed the expansion of a specific subpopulation composed of Tfh, transitional, and central memory CD4+ T cells bearing a phenotype associated with strong activation, differentiation, and exhaustion in patients with mild but not moderate/severe CCC. In contrast, patients with mild and moderate/severe CCC had lower frequencies of CD4+ T cells expressing lower levels of activation markers, suggesting resting status, than CTL. Regarding the B cell compartment, no alterations were found in naïve CD21-, memory cells expressing IgM or IgD, marginal zone, and plasma cells in patients with Chagas disease. However, expansion of class-switched activated and atypical memory B cells was observed in all clinical forms, and more substantially in mild CCC patients. Discussion: Taken together, our results showed that T. cruzi infection triggers changes in CD4+ T and B cell compartments that are more pronounced in the mild CCC clinical form, suggesting an orchestrated cellular communication during Chagas disease. Conclusion: Overall, these findings reinforce the heterogeneity and complexity of the immune response in patients with chronic Chagas disease and may provide new insights into disease pathology and potential markers to guide clinical decisions.