Air Pollution's Impact on Cardiac Remodeling in an Experimental Model of Chagas Cardiomyopathy.

Background: Chagas disease is characterized by intense myocardial fibrosis stimulated by the exacerbated production of inflammatory cytokines, oxidative stress, and apoptosis. Air pollution is a serious public health problem and also follows this same path. Therefore, air pollution might amplify the inflammatory response of Chagas disease and increase myocardial fibrosis. Methods: We studied groups of Trypanosoma cruzi infected Sirius hamsters (Chagas=CH and Chagas exposed to pollution=CH+P) and 2 control groups (control healthy animals=CT and control exposed to pollution=CT+P). We evaluated acute phase (60 days post infection) and chronic phase (10 months). Echocardiograms were performed to assess left ventricular systolic and diastolic diameter, in addition to ejection fraction. Interstitial collagen was measured by morphometry in picrosirius red staining tissue. The evaluation of inflammation was performed by gene and protein expression of cytokines IL10, IFN-γ, and TNF; oxidative stress was quantified by gene expression of NOX1, MnSOD, and iNOS and by analysis of reactive oxygen species; and apoptosis was performed by gene expression of BCL2 and Capsase3, in addition to TUNEL analysis. Results: Chagas groups had increased collagen deposition mainly in the acute phase, but air pollution did not increase this deposition. Also, Chagas groups had lower ejection fraction in the acute phase (p = 0.002) and again air pollution did not worsen ventricular function or dilation. The analysis of the inflammation and oxidative stress pathways were also not amplified by air pollution. Apoptosis analysis showed increased expression of BCL2 and Caspase3 genes in chagasic groups in the acute phase, with a marginal p of 0.054 in BCL2 expression among infected groups, and TUNEL technique showed amplified of apoptotic cells by pollution among infected groups. Conclusions: A possible modulation of the apoptotic pathway was observed, inferring interference from air pollution in this pathway. However, it was not enough to promote a greater collagen deposition, or worsening ventricular function or dilation caused by air pollution in this model of Chagas cardiomyopathy.

Influence of Angiotensin-converting Enzyme Insertion/Deletion Gene Polymorphism in Progression of Chagas Heart Disease.

INTRODUCTION: Chagas disease (CD) is a neglected disease caused by the parasite Trypanosoma cruzi. One-third of infected patients will develop the cardiac form, which may progress to heart failure (HF). However, the factors that determine disease progression remain unclear. Increased angiotensin II activity is a key player in the pathophysiology of HF. A functional polymorphism of the angiotensin-converting enzyme (ACE) gene is associated with plasma enzyme activity. In CD, ACE inhibitors have beneficial effects supporting the use of this treatment in chagasic cardiomyopathy. METHODS: We evaluated the association of ACE I/D polymorphism with HF, performing a case-control study encompassing 343 patients with positive serology for CD staged as non-cardiomyopathy (stage A; 100), mild (stage B1; 144), and severe (stage C; 99) forms of Chagas heart disease. For ACE I/D genotyping by PCR, groups were compared using unconditional logistic regression analysis and adjusted for nongenetic covariates: age, sex, and trypanocidal treatment. RESULTS: A marginal, but not significant (p=0.06) higher prevalence of ACE I/D polymorphism was observed in patients in stage C compared with patients in stage A. Patients in stage C (CD with HF), were compared with patients in stages A and B1 combined into one group (CD without HF); DD genotype/D carriers were prevalent in the HF patients (OR = 2; CI = 1.013.96; p = 0.04). CONCLUSIONS: Our results of this cohort study, comprising a population from the Northeast region of Brazil, suggest that ACE I/D polymorphism is more prevalent in the cardiac form of Chagas disease with HF.

Influence of Angiotensin-converting Enzyme Insertion/Deletion Gene Polymorphism in Progression of Chagas Heart Disease

Abstract INTRODUCTION: Chagas disease (CD) is a neglected disease caused by the parasite Trypanosoma cruzi. One-third of infected patients will develop the cardiac form, which may progress to heart failure (HF). However, the factors that determine disease progression remain unclear. Increased angiotensin II activity is a key player in the pathophysiology of HF. A functional polymorphism of the angiotensin-converting enzyme (ACE) gene is associated with plasma enzyme activity. In CD, ACE inhibitors have beneficial effects supporting the use of this treatment in chagasic cardiomyopathy. METHODS: We evaluated the association of ACE I/D polymorphism with HF, performing a case-control study encompassing 343 patients with positive serology for CD staged as non-cardiomyopathy (stage A; 100), mild (stage B1; 144), and severe (stage C; 99) forms of Chagas heart disease. For ACE I/D genotyping by PCR, groups were compared using unconditional logistic regression analysis and adjusted for nongenetic covariates: age, sex, and trypanocidal treatment. RESULTS: A marginal, but not significant (p=0.06) higher prevalence of ACE I/D polymorphism was observed in patients in stage C compared with patients in stage A. Patients in stage C (CD with HF), were compared with patients in stages A and B1 combined into one group (CD without HF); DD genotype/D carriers were prevalent in the HF patients (OR = 2; CI = 1.013.96; p = 0.04). CONCLUSIONS: Our results of this cohort study, comprising a population from the Northeast region of Brazil, suggest that ACE I/D polymorphism is more prevalent in the cardiac form of Chagas disease with HF.

Dysregulation of insulin levels in Chagas heart disease is associated with altered adipocytokine levels.

Metabolic, inflammatory, and autonomic nervous system (ANS) dysfunction are present in patients with heart failure. However, whether these changes are due to left ventricular dysfunction or heart failure etiology is unknown. We evaluated metabolism and inflammatory activity in patients with idiopathic dilated cardiomyopathy (IDC) and Chagas cardiomyopathy (CHG) and their correlation with the ANS. Forty-six patients were divided into 3 groups: IDC, CHG, and control. We evaluated adiponectin, leptin, insulin, interleukin-6, and tumor necrosis factor-alpha. ANS were analyzed by heart rate variability in time and frequency domains on a 24-hour Holter monitor. Levels of glucose, cholesterol, leptin, and adiponectin did not show differences between groups. Insulin levels were lower in CHG group (5.4 ± 3.3 µU/mL) when compared with control (8.0 ± 4.9 µU/mL) and IDC (9.9 ± 5.0 µU/mL) groups (p = 0.007). Insulin was positively associated with LFr/HFr ratio (r = 0.562; p = 0.029) and with the LFr component (r = 0.562; p = 0.029) and negatively associated with adiponectin (r = -0.603; p = 0.017) in CHG group. The addition of an adiponectin unit reduced average insulin by 0.332 µg/mL. Insulin levels were decreased in the CHG group when compared with the IDC group and were associated with ANS indexes and adiponectin levels.

Erythropoietin reduces collagen deposition after myocardial infarction but does not improve cardiac function.

Myocardial remodeling includes inappropriate collagen deposition in the interstitium. Erythropoietin (EPO) may have cardioprotective effects. We aimed to assess the role of EPO on myocardial remodeling during the chronic phase. We studied 60 Wistar rats divided into the following groups: control (CT), control + EPO (CT + EPO), myocardial infarction + EPO (MI + EPO), and myocardial infarction (MI). The interstitial collagen volume fraction (ICVF) was quantified and echocardiography was performed. We quantified asymmetric dimethylarginine and glutathione by ELISA, and used real-time PCR to assess apoptosis and inflammation. Western blotting was used to evaluate inflammatory proteins and tissue inhibitors of metalloproteinases (TIMPs), and TUNEL staining was used to detect apoptosis. For matrix metalloproteinases (MMPs), we performed zymography. Parametric and nonparametric analyses were performed according to normality testing. ICVF was greater in MI groups (p < 0.001) and was attenuated by EPO (p = 0.05). The MMP-2 did not show any difference between groups. The TIMP-1 and TIMP-2 did not have difference between groups. The MI groups had worse fraction shortening (p < 0.001), without EPO protection (p = 0.666). The MI groups had increased left ventricle diastolic dimension (p < 0.001) without EPO attenuation (p = 0.79). EPO did not act on oxidative stress. Apoptosis and inflammation were not modulated by EPO. We concluded that EPO attenuated interstitial collagen accumulation, but did not protect from heart dilation or dysfunction.

Papel da eritropoetina na atenuação da fibrose miocárdica / The role of erythropoietin upon myocardial fibrosis

Introdução: No processo de remodelamento miocárdico ocorre hipertrofia de miócitos e deposição exacerbada de colágeno no interstício, promovendo alteração na geometria e na função do coração. A eritropoetina (EPO) tem sido amplamente estudada nesse cenário, pois exerce efeitos cardioprotetores. Objetivo: Avaliar o papel da EPO na atenuação do remodelamento estrutural, geométrico e funcional do coração, em modelo experimental de infarto do miocárdio. Materiais e Métodos: Estudados 60 ratos Wistar machos divididos em 4 grupos (Controle; Controle+EPO; Infartado; Infartado+EPO). A fração do volume de colágeno intersticial do ventrículo esquerdo (FVCI-VE) e do ventrículo direito (FVCI-VD) foi determinada em cortes histológicos, corados com picrosirus red utilizando-se o programa QWIN Image Processing and Analysis Software (Leica Microsystems Cambridge Ltd.). Essas mesmas lâminas e o software foram utilizados para a medida do tamanho da área de infarto. A análise anatômica e funcional foi realizada por ecocardiograma, avaliando-se a fração de encurtamento do VE (FE) e o diâmetro diastólico do VE (DDVE). Para o estresse oxidativo, dois kits comerciais foram utilizados na determinação da glutationa e do ADMA. A sobrecarga ventricular, apoptose e inflamação foram realizadas por PCR, em tempo real. Na avaliação da angiogênese, utilizamos a técnica de imunohistoquímica. A análise hematológica foi realizada por exames laboratoriais para dosagem de hemoglobina e hematócrito. Resultados: A FVCI-VE (%) foi maior nos grupos infartados em relação aos grupos controles (p < 0,001), e atenuada pela EPO (p < 0,001, IAM vs IAM+EPO) (CT = 0,76 ± 0,21; CT+EPO = 0,63 ± 0,15; IAM+EPO = 1,43 ± 0,92; IAM= 3,47 ± 2,5). A FVCI-VD (%) também foi maior nos infartados em relação aos grupos controles (CT = 0,60 ± 0,2; CT+EPO = 0,83 ± 0,3; IAM+EPO = 1,01 ± 0,55; IAM = 1,60 ± 1,15) (p < 0,001), mas sem diferença estatística quando comparados os grupos IAM vs IAM+EPO....

Introduction: The process of myocardial remodeling include inappropriate collagen deposition in the interstitium developing an overall process of structural and geometric remodeling of the heart. Erythropoietin (EPO) may have a cardioprotective effects including inflammatory and oxidative stress modulation. Objective: The aim of this study was to assess the role of EPO upon structural, geometric and functional remodeling at the heart. Materials and Methods: 60 Wistar rats were divided into 4 groups: Control, Control+EPO, Infarcted, Infarcted+EPO. Interstitial collagen volume fraction in the left (LV-ICVF) and right ventricle (RV-ICVF) was quantified by videomorphometry using a QWIN Image Processing and Analysis Software (Leica Microsystems Cambridge Ltd.). These same slides and software were also used to measure the size of the infarct area. The analyzed echocardiographic parameters were the left ventricle shortening fraction (LVFS) and diastolic diameter (LVDD). For oxidative stress, two commercial kits were used in to quantify ADMA and glutathione. RT-PCR was used to assess ventricular overload, apoptosis and inflammatory cytokines. For angiogenesis we used immunohistochemistry and hematological analysis was performed by laboratory tests for hemoglobin and hematocrit. Non parametric analysis was performed and p <=0.05 was considered significant. Results: LV-ICVF (%) was greater in the infarcted groups compared to controls (p < 0.001), and attenuated by EPO (p = 0.05, MI vs MI+EPO) (CT = 0.76 ± 0.20; CT+EPO = 0.62 ± 0.16; MI+EPO = 1.22 ± 0.86; MI = 3.80 ± 2.6). The RV-ICVF (%) was also greater in the infarcted groups compared to controls (CT = 0.60 ± 0.2; CT+EPO = 0.82 ± 0.28; MI+EPO = 1.02 ± 0.58; IAM = 1.62 ± 1.20) (p = 0.007) but without statistical difference between MI vs MI+EPO. Regarding infarct size we did not observe any difference. The infarcted groups had a worsening shortening fraction compared to controls (CT = 45.65% ± 6.4;...

Effect of colchicine on myocardial injury induced by Trypanosoma cruzi in experimental Chagas disease.

BACKGROUND: The hallmark of Chagas disease (CD) is multifocal myocarditis and extensive fibrosis. We investigated the potential effect of colchicine on myocardial remodeling in experimental CD. METHODS AND RESULTS: One hundred Syrian hamsters were randomly divided into noninfected untreated control (CG), noninfected control treated with colchicine (COLG 0.4 mg kg(-1) d(-1) by gavage), infected (IG), and infected treated with colchicine (ICOLG, 0.4 mg kg(-1) d(-1)) groups. The interstitial collagen volume fraction (ICVF) was evaluated by videomorphometry with picrosirius red staining. The gelatinolytic activities of matrix metalloproteinase (MMP) 2 were examined with the use of zymography. Myocarditis was described according to the Dallas criteria. Statistical comparisons were performed with parametric analysis of variance and Tukey test. ICVF (%) accumulation was attenuated in infected colchicine-treated animals in the left (CG 0.81 ± 0.13, COLG 0.85 ± 0.13, IG: 1.35 ± 0.31,* ICOLG 1.06 ± 0.19; *P < .05 compared with ICOLG) and right ventricles (CG 1.4 ± 0.36, COLG 1.26 ± 0.14, IG 1.97 ± 0.058,* ICOLG: 1.52 ± 0.23; *P < .05 compared with ICOLG). A significant increase in MMP-2 enzymatic activity (UA) was observed in ICOLG (17,432.8*) compared with GC (3731.6), COLG (2,792.6), and IG (4,286.3; *P < .001). In IG, 66% of animals had myocarditis compared with only 49% in ICOLG. CONCLUSIONS: Colchicine had a protective effect on myocardium, indicated by decreased interstitial myocardial fibrosis, increased intensity of MMP-2, and attenuated myocardial inflammation.