Biomarkers and Echocardiographic Predictors of Cardiovascular Outcome in Patients With Chronic Chagas Disease.

Background Chagas disease (CD) presents an ominous prognosis. The predictive value of biomarkers and new echocardiogram parameters in adjusted models have not been well studied. Methods and Results There were 361 patients with chronic CD (57.6% men, 61±11 years of age, clinical forms: indeterminate 27.1%, cardiac 56.6%, digestive 3.6%, cardiodigestive 12.7%) included in this single-center, observational, prospective longitudinal study. Echocardiographic evaluation included strain analyses of left atrial, left ventricular (LV), and right ventricular and 3-dimensional analyses of left atrial and LV volumes. Biomarkers included cardiac troponin I, brain natriuretic peptide, transforming growth factor ß1, tumor necrosis factor, matrix metalloproteinases, and Trypanosoma cruzi polymerase chain reaction. The studied end point was a composite of CD-related mortality, heart transplant, hospital admission due to worsening heart failure, or new cardiac device insertion. Event-free survival was analyzed by multivariable regression analyses adjusted for competing risks. P values <0.05 were considered significant. The composite event occurred in 79 patients after 4.9±2.0 years follow-up. LV end-diastolic volume (hazard ratio [HR], 1.01 [95% CI, 1.00-1.02]; P=0.02), peak negative global atrial strain (HR, 1.08 [95% CI, 1.00-1.17]; P=0.04), LV global circumferential strain (HR, 1.12 [95% CI, 1.04-1.21]; P=0.003), LV torsion (HR, 0.55 [95% CI, 0.35-0.81]; P=0.003), brain natriuretic peptide (HR, 2.03 [95% CI, 1.23-3.34]; P=0.005), and positive T cruzi polymerase chain reaction (HR, 1.80 [95% CI, 1.12-2.91]; P=0.01) were end point predictors independent from age, sex, 2-dimensional echocardiographic indexes, hypertension, previous cardiac device, and CD cardiac form. Conclusions Two-dimensional strain- and 3-dimensional-derived parameters, brain natriuretic peptide, and positive T cruzi polymerase chain reaction can be useful for prediction of CD cardiovascular events.

Trypanosoma cruzi Promotes Transcriptomic Remodeling of the JAK/STAT Signaling and Cell Cycle Pathways in Myoblasts.

Chagas disease is responsible for more than 10,000 deaths per year and about 6 to 7 million infected people worldwide. In its chronic stage, patients can develop mega-colon, mega-esophagus, and cardiomyopathy. Differences in clinical outcomes may be determined, in part, by the genetic background of the parasite that causes Chagas disease. Trypanosoma cruzi has a high genetic diversity, and each group of strains may elicit specific pathological responses in the host. Conflicting results have been reported in studies using various combinations of mammalian host-T. cruzi strains. We previously profiled the transcriptomic signatures resulting from infection of L6E9 rat myoblasts with four reference strains of T. cruzi (Brazil, CL, Y, and Tulahuen). The four strains induced similar overall gene expression alterations in the myoblasts, although only 21 genes were equally affected by all strains. Cardiotrophin-like cytokine factor 1 (Clcf1) was one of the genes found to be consistently upregulated by the infection with all four strains of T. cruzi. This cytokine is a member of the interleukin-6 family that binds to glycoprotein 130 receptor and activates the JAK/STAT signaling pathway, which may lead to muscle cell hypertrophy. Another commonly upregulated gene was tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein theta (Ywhaq, 14-3-3 protein Θ), present in the Cell Cycle Pathway. In the present work, we reanalyzed our previous microarray dataset, aiming at understanding in more details the transcriptomic impact that each strain has on JAK/STAT signaling and Cell Cycle pathways. Using Pearson correlation analysis between the expression levels of gene pairs in biological replicas from each pathway, we determined the coordination between such pairs in each experimental condition and the predicted protein interactions between the significantly altered genes by each strain. We found that although these highlighted genes were similarly affected by all four strains, the downstream genes or their interaction partners were not necessarily equally affected, thus reinforcing the idea of the role of parasite background on host cell transcriptome. These new analyses provide further evidence to the mechanistic understanding of how distinct T. cruzi strains lead to diverse remodeling of host cell transcriptome.