Ronaldo Honorato Barros Santos

Myocardial Chemokine Expression and Intensity of Myocarditis in Chagas Cardiomyopathy Are Controlled by Polymorphisms in CXCL9 and CXCL10

Background Chronic Chagas cardiomyopathy (CCC), a life-threatening inflammatory dilated cardiomyopathy, affects 30% of the approximately 8 million patients infected by Trypanosoma cruzi. Even though the Th1 T cell-rich myocarditis plays a pivotal role in CCC pathogenesis, little is known about the factors controlling inflammatory cell migration to CCC myocardium. Methods and Results Using confocal immunofluorescence and quantitative PCR, we studied cell surface staining and gene expression of the CXCR3, CCR4, CCR5, CCR7, CCR8 receptors and their chemokine ligands in myocardial samples from end-stage CCC patients. CCR5+, CXCR3+, CCR4+, CCL5+ and CXCL9+ mononuclear cells were observed in CCC myocardium. mRNA expression of the chemokines CCL5, CXCL9, CXCL10, CCL17, CCL19 and their receptors was upregulated in CCC myocardium. CXCL9 mRNA expression directly correlated with the intensity of myocarditis, as well as with mRNA expression of CXCR3, CCR4, CCR5, CCR7, CCR8 and their ligands. We also analyzed single-nucleotide polymorphisms for genes encoding the most highly expressed chemokines and receptors in a cohort of Chagas disease patients. CCC patients with ventricular dysfunction displayed reduced genotypic frequencies of CXCL9 rs10336 CC, CXCL10 rs3921 GG, and increased CCR5 rs1799988CC as compared to those without dysfunction. Significantly, myocardial samples from CCC patients carrying the CXCL9/CXCL10 genotypes associated to a lower risk displayed a 2–6 fold reduction in mRNA expression of CXCL9, CXCL10, and other chemokines and receptors, along with reduced intensity of myocarditis, as compared to those with other CXCL9/CXCL10 genotypes. Conclusions Results may indicate that genotypes associated to reduced risk in closely linked CXCL9 and CXCL10 genes may modulate local expression of the chemokines themselves, and simultaneously affect myocardial expression of other key chemokines as well as intensity of myocarditis. Taken together our results may suggest that CXCL9 and CXCL10 are master regulators of myocardial inflammatory cell migration, perhaps affecting clinical progression to the life-threatening form of CCC.

MicroRNAs miR-1, miR-133a, miR-133b, miR-208a and miR-208b are dysregulated in Chronic Chagas disease Cardiomyopathy

BACKGROUND/METHODS Chagas disease is caused by an intracellular parasite, Trypanosoma cruzi, and it is a leading cause of heart failure in Latin America. The main clinical consequence of the infection is the development of a Chronic Chagas disease Cardiomyopathy (CCC), which is characterized by myocarditis, hypertrophy and fibrosis and affects about 30% of infected patients. CCC has a worse prognosis than other cardiomyopathies, like idiopathic dilated cardiomyopathy (DCM). It is well established that myocardial gene expression patterns are altered in CCC, but the molecular mechanisms underlying these differences are not clear. MicroRNAs are recently discovered regulators of gene expression, and are recognized as important factors in heart development and cardiovascular disorders (CD). We analyzed the expression of nine different miRNAs in myocardial tissue samples of CCC patients in comparison to DCM patients and samples from heart transplant donors. Using the results of a cDNA microarray database on CCC and DCM myocardium, signaling networks were built and nodal molecules were identified. RESULTS We observed that five miRNAs were significantly altered in CCC and three in DCM; importantly, three miRNAs were significantly reduced in CCC as compared to DCM. We observed that multiple gene targets of the differentially expressed miRNAs showed a concordant inverse expression in CCC. Significantly, most gene targets and involved networks belong to crucial disease-related signaling pathways. CONCLUSION These results suggest that miRNAs may play a major role in the regulation of gene expression in CCC pathogenesis, with potential implication as diagnostic and prognostic tools.

Myocardial Gene Expression of T-bet, GATA-3, Ror-γt, FoxP3, and Hallmark Cytokines in Chronic Chagas Disease Cardiomyopathy: An Essentially Unopposed TH1-Type Response

Background. Chronic Chagas disease cardiomyopathy (CCC), a late consequence of Trypanosoma cruzi infection, is an inflammatory cardiomyopathy with prognosis worse than those of noninflammatory etiology (NIC). Although the T cell-rich myocarditis is known to play a pathogenetic role, the relative contribution of each of the functional T cell subsets has never been thoroughly investigated. We therefore assessed gene expression of cytokines and transcription factors involved in differentiation and effector function of each functional T cell subset (TH1/TH2/TH17/Treg) in CCC, NIC, and heart donor myocardial samples. Methods and Results. Quantitative PCR showed markedly upregulated expression of IFN-γ and transcription factor T-bet, and minor increases of GATA-3; FoxP3 and CTLA-4; IL-17 and IL-18 in CCC as compared with NIC samples. Conversely, cytokines expressed by TH2 cells (IL-4, IL-5, and IL-13) or associated with Treg (TGF-β and IL-10) were not upregulated in CCC myocardium. Expression of TH1-related genes such as T-bet, IFN-γ, and IL-18 correlated with ventricular dilation, FoxP3, and CTLA-4. Conclusions. Results are consistent with a strong local TH1-mediated response in most samples, possibly associated with pathological myocardial remodeling, and a proportionally smaller FoxP3+CTLA4+ Treg cell population, which is unable to completely curb IFN-γ production in CCC myocardium, therefore fueling inflammation.

Polymorphism in the Alpha Cardiac Muscle Actin 1 Gene Is Associated to Susceptibility to Chronic Inflammatory Cardiomyopathy

Aims Chagas disease, caused by the protozoan Trypanosoma cruzi is endemic in Latin America, and may lead to a life-threatening inflammatory dilated, chronic Chagas cardiomyopathy (CCC). One third of T. cruzi-infected individuals progress to CCC while the others remain asymptomatic (ASY). A possible genetic component to disease progression was suggested by familial aggregation of cases and the association of markers of innate and adaptive immunity genes with CCC development. Since mutations in multiple sarcomeric genes, including alpha-cardiac actin (ACTC1) have been involved in hereditary dilated cardiomyopathy, we investigated the involvement of the ACTC1 gene in CCC pathogenesis. Methods and Results We conducted a proteomic and genetic study on a Brazilian study population. The genetic study was done on a main cohort including 118 seropositive asymptomatic subjects and 315 cases and the replication was done on 36 asymptomatic and 102 CCC cases. ACTC1 protein and mRNA levels were lower in myocardial tissue from patients with end-stage CCC than those found in hearts from organ donors. Genotyping a case-control cohort of CCC and ASY subjects for all informative single nucleotide polymorphism (SNP) in the ACTC1 gene identified rs640249 SNP, located at the 5’ region, as associated to CCC. Associations are borderline after correction for multiple testing. Correlation and haplotype analysis led to the identification of a susceptibility haplotype. Functional assays have shown that the rs640249A/C polymorphism affects the binding of transcriptional factors in the promoter regions of the ACTC1 gene. Confirmation of the detected association on a larger independent replication cohort will be useful. Conclusions Genetic variations at the ACTC1 gene may contribute to progression to chronic Chagas Cardiomyopathy among T. cruzi-infected patients, possibly by modulating transcription factor binding to ACTC1 promoter regions.

Impact of sublingual sildenafil on pulmonary hypertension in patients with heart failure

BACKGROUND Pulmonary hypertension (PH) is a factor of poor prognosis in the postoperative period of heart transplant (HT) and thus, the study of the degree of reversibility to vasodilators is mandatory during the preoperative assessment. OBJECTIVE To evaluate the pulmonary and systemic hemodynamic effects of sildenafil as a vasodilator during the PH reversibility test in patients that are candidates to HT. METHODS Patients awaiting HT were submitted to the measurement of systemic and pulmonary hemodynamic variables before and after the administration of a single sublingual dose of 100 mg of sildenafil during right heart catheterization. RESULTS Fourteen patients (age: 47+/-12 years, 71.4% men) with advanced heart failure Ejection Fraction (EF) 25 +/- 7%, Functional Class (FC - NYHA) FC III - 6 and FC IV - 8, were evaluated in this study. The acute administration of sildenafil showed to be effective in decreasing the systolic (62.4 +/- 12.1 vs 51.5 +/- 9.6 mmHg, CI=95%, p<0.05) and mean (40.7 +/- 7.3 vs 33.8 +/- 7.6 mmHg, CI=95%, p <0.05) pressures of the pulmonary artery. There was also a significant decrease in the pulmonary (4.2 +/- 3 vs 2.0 +/- 0.9 uWood, CI=95%, p<0.05) and systemic vascular resistance (22.9 +/- 6.8 vs 18.6 +/- 4.1 Wood, CI=95%, p<0.05), associated to an increase in the cardiac output (3.28 +/- 0.79 vs 4.12 +/-1.12 uWood, CI=95%, p<0.05) without, however, significantly interfering in the systemic arterial pressure (87.8 +/- 8.2 vs 83.6 +/- 9.1 mmHg, CI=95%, p=0.3). CONCLUSION The sublingual administration of sildenafil is an effective and safe alternative as a vasodilator during the PH reversibility test in patients with heart failure and awaiting a HT.FUNDAMENTO: La hipertension pulmonar (HP) se muestra factor de mal pronostico en el postoperatorio de transplante cardiaco (TC) y, de esta forma, el estudio del grado de reversibilidad a vasodilatadores se vuelve obligatorio durante evaluacion preoperatoria. OBJETIVO: Evaluar los efectos hemodinamicos pulmonares y sistemicos del Sildenafil como droga vasodilatadora durante la prueba de reversibilidad de la HP en candidatos a transplante cardiaco. METODOS: Pacientes en fila para TC fueron sometidos a la medicion de variables hemodinamicas sistemicas y pulmonares, antes y luego de la administracion de 100mg en dosificacion unica y sublingual de Sildenafil, durante cateterizacion cardiaca derecha. RESULTADOS: Se evaluaron en este estudio a 14 pacientes (edad: 47±12 anos, el 71,4% varones) con insuficiencia cardiaca avanzada, fraccion de eyeccion (FE) 25 ± 7%, clase funcional (CF-NYHA) CF III - 6 y CF IV - 8. La administracion aguda de Sildenafil se mostro eficaz en la reduccion de las presiones sistolica (62,4 ± 12,1 vs 51,5 ± 9,6 mmHg, IC=95%, p<0,05) y media (40,7 ± 7,3 vs 33,8 ± 7,6 mmHg, IC=95%, p <0,05) de la arteria pulmonar. Hubo tambien una reduccion significativa de la resistencia vascular pulmonar (4,2 ± 3 vs 2,0 ± 0,9 uWood, IC=95%, p<0,05) y sistemica (22,9 ± 6,8 vs 18,6 ± 4,1 Wood, IC=95%, p<0,05), asociada a una elevacion del debito cardiaco (3,28 ± 0,79 vs 4,12 ±1,12 uWood, IC=95%, p<0,05) sin, con todo, interferir de manera significativa en la presion arterial sistemica (87,8 ± 8,2 vs 83,6 ± 9,1 mmHg, IC=95%, p=0,3). CONCLUSION: El Sildenafil sublingual resulta una alternativa eficaz y segura como droga vasodilatadora durante la prueba de reversibilidad de la HP en portadores de insuficiencia cardiaca y en fila para transplante cardiaco.

Myocardial Infarction–Associated Transcript, a Long Noncoding RNA, Is Overexpressed During Dilated Cardiomyopathy Due to Chronic Chagas Disease

Long noncoding RNAs (lncRNAs) modulate gene expression at the epigenetic, transcriptional, and posttranscriptional levels. Dysregulation of the lncRNA known as myocardial infarction-associated transcript (MIAT) has been associated with myocardial infarction. Chagas disease causes a severe inflammatory dilated chronic cardiomyopathy (CCC). We investigated the role of MIAT in CCC. A whole-transcriptome analysis of heart biopsy specimens and formalin-fixed, paraffin-embedded samples revealed that MIAT was overexpressed in patients with CCC, compared with subjects with noninflammatory dilated cardiomyopathy and controls. These results were confirmed in a mouse model. Results suggest that MIAT is a specific biomarker of CCC.

Selective Decrease of Components of the Creatine Kinase System and ATP Synthase Complex in Chronic Chagas Disease Cardiomyopathy

Background Chronic Chagas disease cardiomyopathy (CCC) is an inflammatory dilated cardiomyopathy with a worse prognosis than other cardiomyopathies. CCC occurs in 30 % of individuals infected with Trypanosoma cruzi, endemic in Latin America. Heart failure is associated with impaired energy metabolism, which may be correlated to contractile dysfunction. We thus analyzed the myocardial gene and protein expression, as well as activity, of key mitochondrial enzymes related to ATP production, in myocardial samples of end-stage CCC, idiopathic dilated (IDC) and ischemic (IC) cardiomyopathies. Methodology/Principal Findings Myocardium homogenates from CCC (N = 5), IC (N = 5) and IDC (N = 5) patients, as well as from heart donors (N = 5) were analyzed for protein and mRNA expression of mitochondrial creatine kinase (CKMit) and muscular creatine kinase (CKM) and ATP synthase subunits aplha and beta by immunoblotting and by real-time RT-PCR. Total myocardial CK activity was also assessed. Protein levels of CKM and CK activity were reduced in all three cardiomyopathy groups. However, total CK activity, as well as ATP synthase alpha chain protein levels, were significantly lower in CCC samples than IC and IDC samples. CCC myocardium displayed selective reduction of protein levels and activity of enzymes crucial for maintaining cytoplasmic ATP levels. Conclusions/Significance The selective impairment of the CK system may be associated to the loss of inotropic reserve observed in CCC. Reduction of ATP synthase alpha levels is consistent with a decrease in myocardial ATP generation through oxidative phosphorylation. Together, these results suggest that the energetic deficit is more intense in the myocardium of CCC patients than in the other tested dilated cardiomyopathies.

A doença coronária aumenta a mortalidade hospitalar de portadores de estenose aórtica submetidos à substituição valvar

OBJECTIVES With the increase in life expectancy occurred in recent decades, it has been noted the concomitant increase in the prevalence of aortic stenosis and degenerative disease of atherosclerotic coronary artery. This study aims to evaluate the influence of atherosclerotic coronary artery disease in patients with critical aortic stenosis undergoing isolated or combined implant valve prosthesis and coronary artery by pass grafting. METHODS In the period of January 2001 to March 2006, there were analyzed 448 patients undergoing isolated implant aortic valve prosthesis (Group I) and 167 patients undergoing aortic valve prosthesis implant combined with coronary artery bypass grafting (Group II). Pre- and intra-operative variables elected for analysis were: age, gender, body mass index, stroke, diabetes mellitus, chronic obstructive pulmonary disease, rheumatic fever, hypertension, endocarditis, acute myocardial infarction, smoking, Fraction of the left ventricular ejection, critical atherosclerotic coronary artery disease, chronic atrial fibrillation, aortic valve operation prior (conservative), functional class of congestive heart failure, value serum creatinine, total cholesterol, size of the prosthesis used, length and number of distal anastomoses held in myocardial revascularization, duration of cardiopulmonary bypass and aortic clamping time. The statistical study employed invariant and multivariate analysis. RESULTS Hospital mortality was 14.3% (64 deaths) in Group I, and 14.5% (58 deaths) in patients with atherosclerotic coronary artery disease associated criticism (Group IB) and 12.8% (six deaths) in which had this association (Group IA). Hospital mortality in Group II was 17.6% (29 deaths), and 16.1% (20 deaths) in patients undergoing implantation of prosthetic aortic valve combined to complete myocardial revascularization (Group II) and 20.9% (nine deaths) in the myocardial revascularization with incomplete (Group IIB). CONCLUSIONS In patients undergoing implant isolated from aortic valve prosthesis, the presence of atherosclerotic coronary artery disease associated critical in at least two arteries, influenced the hospital mortality. In patients undergoing surgical treatment combined the number of coronary arteries with critical atherosclerotic disease and extent of coronary artery bypass grafting (complete or incomplete), did not affect the hospital mortality, but the realization of more than three anastomoses in the distal myocardial revascularization interfered.

Sildenafil vs. Nitroprussiato de Sódio durante Teste de Reatividade Pulmonar pré-transplante cardíaco

BACKGROUND: Pulmonary hypertension is associated with a worse prognosis after cardiac transplantation. The pulmonary hypertension reversibility test with sodium nitroprusside (SNP) is associated with a high rate of systemic arterial hypotension, ventricular dysfunction of the transplanted graft and high rates of disqualification from transplantation. OBJECTIVE: This study was aimed at comparing the effects of sildenafil (SIL) and SNP on hemodynamic, neurohormonal and echocardiographic variables during the pulmonary reversibility test. METHODS: The patients underwent simultaneously right cardiac catheterization, echocardiography, BNP measurement, and venous blood gas analysis before and after receiving either SNP (1 - 2 µg/kg/min) or SIL (100 mg, single dose). RESULTS: Both drugs reduced pulmonary hypertension, but SNP caused a significant systemic hypotension (mean blood pressure - MBP: 85.2 vs. 69.8 mm Hg; p < 0.001). Both drugs reduced cardiac dimensions and improved left cardiac function (SNP: 23.5 vs. 24.8%, p = 0.02; SIL: 23.8 vs. 26%, p < 0.001) and right cardiac function (SIL: 6.57 ± 2.08 vs. 8.11 ± 1.81 cm/s, p = 0.002; SNP: 6.64 ± 1.51 vs. 7.72 ± 1.44 cm/s, p = 0.003), measured through left ventricular ejection fraction and tissue Doppler, respectively. Sildenafil, contrary to SNP, improved venous oxygen saturation, measured on venous blood gas analysis. CONCLUSION: Sildenafil and SNP are vasodilators that significantly reduce pulmonary hypertension and cardiac geometry, in addition to improving biventricular function. Sodium nitroprusside, contrary to SIL, was associated with systemic arterial hypotension and worsening of venous oxygen saturation.

Can tricuspid annuloplasty of the donor heart reduce valve insufficiency following cardiac transplantation with bicaval anastomosis

BACKGROUND The aim of this study was to evaluate the degree of tricuspid valve insufficiency after orthotopic cardiac transplantation with bicaval anastomosis and prophylactic donor heart annuloplasty. METHODS At present, our cardiac transplantation experience includes 478 cases. After January 2002, we included 30 consecutive patients in this study who had undergone orthotopic cardiac transplantation and survived >6 months. The patients were divided into 2 groups: group I, 15 patients who underwent transplantation with prophylactic tricuspid annuloplasty on the donor heart with the De Vega technique; and group II, 15 patients who underwent transplantation without this procedure. Their preoperative clinical characteristics were the same. During the late postoperative follow-up, the degree of tricuspid insufficiency was evaluated by transthoracic Doppler echocardiography and assessed according to the Simpson scale: 0, absent; 1, mild; 2, moderate; and 3, severe. Hemodynamic parameters were evaluated invasively by means of a Swan-Ganz catheter during routine endomyocardial biopsies. RESULTS The mean follow-up time was 26.9 +/- 5.4 months (range, 12-36 months). In group I, 1 patient (6.6%) died from infection in the 18th month after the operation; the death was not related to the annuloplasty. In group II, 1 death (6.6%) occurred after 10 months because of rejection (P > .05). After the 24-month follow-up, the mean degree of tricuspid insufficiency was 0.4 +/- 0.5 in group I and 1.7 +/- 0.9 in group II (P < .05). Similarly, the 2 groups were significantly different with respect to the right atrium pressure, which was higher in group II. CONCLUSIONS Prophylactic tricuspid annuloplasty on the donor heart was able to reduce significantly the degree of valvular insufficiency, even in cardiac transplantation with bicaval anastomosis; however, it did not modify significantly the hemodynamic performance of the allograft during the investigation period. It is very important to extend the observation period and casuistics to verify other benefits that this technique may offer.