MEF2C repressor variant deregulation leads to cell cycle re-entry and development of heart failure.

BACKGROUND: A pathophysiological link exists between dysregulation of MEF2C transcription factors and heart failure (HF), but the underlying mechanisms remain elusive. Alternative splicing of MEF2C exons α, ß and γ provides transcript diversity with gene activation or repression functionalities. METHODS: Neonatal and adult rat ventricular myocytes were used to overexpress MEF2C splicing variants γ+ (repressor) or γ-, or the inactive MEF2Cγ+23/24 (K23T/R24L). Phenotypic alterations in cardiomyocytes were determined by confocal and electron microscopy, flow cytometry and DNA microarray. We used transgenic mice with cardiac-specific overexpression of MEF2Cγ+ or MEF2Cγ- to explore the impact of MEF2C variants in cardiac phenotype. Samples of non-infarcted areas of the left ventricle from patients and mouse model of myocardial infarction were used to detect the expression of MEF2Cγ+ in failing hearts. FINDINGS: We demonstrate a previously unrealized upregulation of the transrepressor MEF2Cγ+ isoform in human and mouse failing hearts. We show that adenovirus-mediated overexpression of MEF2Cγ+ downregulates multiple MEF2-target genes, and drives incomplete cell-cycle reentry, partial dedifferentiation and apoptosis in the neonatal and adult rat. None of these changes was observed in cardiomyocytes overexpressing MEF2Cγ-. Transgenic mice overexpressing MEF2Cγ+, but not the MEF2Cγ-, developed dilated cardiomyopathy, correlated to cell-cycle reentry and apoptosis of cardiomyocytes. INTERPRETATION: Our results provide a mechanistic link between MEF2Cγ+ and deleterious abnormalities in cardiomyocytes, supporting the notion that splicing dysregulation in MEF2C towards the selection of the MEF2Cγ+ variant contributes to the pathogenesis of HF by promoting cardiomyocyte dropout. FUNDING: São Paulo Research Foundation (FAPESP); Brazilian National Research Council (CNPq).

Right and left ventricular function and myocardial scarring in adult patients with sickle cell disease: a comprehensive magnetic resonance assessment of hepatic and myocardial iron overload.

BACKGROUND: Patients with Sickle cell disease (SCD) who receive regular transfusions are at risk for developing cardiac toxicity from iron overload. The aim of this study was to assess right and left cardiac volumes and function, late gadolinium enhancement (LGE) and iron deposits in patients with SCD using CMR, correlating these values with transfusion burden, ferritin and hemoglobin levels. METHODS: Thirty patients with SCD older than 20 years of age were studied in a 1.5 T scanner and compared to age- and sex-matched normal controls. Patients underwent analysis of biventricular volumes and function, LGE and T2* assessment of the liver and heart. RESULTS: When compared to controls, patients with SCD presented higher left ventricular (LV) volumes with decreased ejection fraction (EF) with an increase in stroke volume (SV) and LV hypertrophy. The right ventricle (RV) also presented with a decreased EF and hypertrophy, with an increased end-systolic volume. Although twenty-six patients had increased liver iron concentrations (median liver iron concentration value was 11.83 ± 9.66 mg/g), only one patient demonstrated an abnormal heart T2* < 20 msec. Only four patients (13%) LGE, with only one patient with an ischemic pattern. CONCLUSIONS: Abnormal heart iron levels and myocardial scars are not a common finding in SCD despite increased liver iron overload. The significantly different ventricular function seen in SCD compared to normal suggests the changes in RV and LV function may not be due to the anemia alone. Future studies are necessary to confirm this association.

Left and right ventricular function and volume assessment in young thalassemia major patients with no related myocardial iron overload.

Thalassemia major (TM) patients have altered ventricular volumes and ejection fraction compared to normals, although evidence for these findings stem from restricted patient groups and has never been reproduced. We sought to evaluate cardiac parameters by cardiovascular magnetic resonance (CMR) in a group of young TM patients not covered by previous studies that are more representative of the TM population in many countries. Seventy patients including 40 TM with normal myocardial iron concentrations, and 30 age- and gender-matched normal (NL) volunteers underwent a CMR study for assessment of left and right ventricle volumes and function using a 1.5-T scanner. Left and right ventricle ejection fraction, indexed systolic and diastolic volumes, and indexed mass were compared between the two groups. Mean age of TM patients was 18.2 ± 7.1 versus 17.5 ± 8.5 years in NL with no significant differences (P = 0.73). There was no difference in left ventricular (LV) ejection fraction between the groups (TM 64.9 ± 5.7 %, NL 64.9 ± 5.2 %; P = 0.97). LV normalized end-diastolic and end-systolic volumes were significantly higher in patients with TM compared to NL volunteers (76.8 ± 19.4 versus 66.6 ± 11.7 mL/m², P = 0.008, and 27.0 ± 8.8 versus 23.6 ± 5.0 mL/m², P = 0.045). LV indexed mass was also higher in TM patients compared to NL (51.2 ± 11.9 versus 42.0 ± 8.5 g/m², P < 0.001). No significant differences were observed in right ventricular parameters. In conclusion, younger patients with TM do not present different left or right ventricular function values compared to normal controls despite having increased left ventricular volumes and mass.

Heart and liver T2 assessment for iron overload using different software programs.

OBJECTIVES: To assess the level of agreement and interchangeability among different software programs for calculation of T2 values for iron overload. METHODS: T2 images were analysed in 60 patients with thalassaemia major using the truncation method in three software programs. Levels of agreement were assessed using Pearson correlation and Bland-Altman plots. Categorical classification for levels of iron concentration by each software program was also compared. RESULTS: For the heart, all correlation coefficients were significant among the software programs (P < 0.001 for all coefficients). The mean differences and 95% limits of agreement were 0.2 (-4.73 to 5.0); 0.1 (-4.0 to 3.9); and -0.1 (-4.3 to 4.8). For the liver all correlations were also significant with P < 0.001. Bland-Altman plots showed differences of -0.02 (-0.7 to 0.6); 0.01 (-0.4 to 0.4); and -0.02 (-0.6 to 0.6). There were no significant differences in clinical classification among the software programs. CONCLUSIONS: All tools used in this study provided very good agreement among heart and liver T2 values. The results indicate that interpretation of T2 data is interchangeable with any of the software programs tested. KEY POINTS: Magnetic resonance imaging in iron overload assessment has become an essential tool. Post processing options to establish T2 values have not been compared. No differences were found on T2 of the liver or heart using 3 different techniques. Availability of these methods should allow more widespread interpretation of iron overload by MRI.

Comparison of inhaled nitric oxide versus oxygen on hemodynamics in patients with mitral stenosis and severe pulmonary hypertension after mitral valve surgery.

Pulmonary hypertension represents an important cause of morbidity and mortality in patients with mitral stenosis who undergo cardiac surgery, especially in the postoperative period. The aim of this study was to test the hypothesis that inhaled nitric oxide (iNO) would improve the hemodynamic effects and short-term clinical outcomes of patients with mitral stenosis and severe pulmonary hypertension who undergo cardiac surgery in a randomized, controlled study. Twenty-nine patients (4 men, 25 women; mean age 46 ± 2 years) were randomly allocated to receive iNO (n = 14) or oxygen (n = 15) for 48 hours immediately after surgery. Hemodynamic data, the use of vasoactive drugs, duration of stay, and short-term complications were assessed. No differences in baseline characteristics were observed between the groups. After 24 and 48 hours, patients receiving iNO had a significantly greater increase in cardiac index compared to patients receiving oxygen (p <0.0001). Pulmonary vascular resistance was also more significantly reduced in patients receiving iNO versus oxygen (-117 dyne/s/cm(5), 95% confidence interval -34 to -200, vs 40 dyne/s/cm(5), 95% confidence interval -34 to 100, p = 0.005) at 48 hours. Patients in the iNO group used fewer systemic vasoactive drugs (mean 2.1 ± 0.14 vs 2.6 ± 0.16, p = 0.046) and had a shorter intensive care unit stay (median 2 days, interquartile range 0.25, vs median 3 days, interquartile range 7, p = 0.02). In conclusion, iNO immediately after surgery in patients with mitral stenosis and severe pulmonary hypertension improves hemodynamics and may have short-term clinical benefits.

Preoperative B-type natriuretic peptide, and not the inflammation status, predicts an adverse outcome for patients undergoing heart surgery.

OBJECTIVES: B-type natriuretic peptide (BNP) and inflammatory markers are implicated in the pathophysiology of both ischemic cardiomyopathy and complications after cardiac surgery with cardiopulmonary bypass (CPB). The purpose of this study was to assess preoperative and postoperative levels of BNP, interleukin-6 (IL-6), interleukin-8 (IL-8), P-selectin, intercellular adhesion molecule (ICAM), C-reactive protein (CRP) in patients undergoing cardiac surgery with CPB and investigate their variation and ability to correlate with immediate outcome. METHODS: Plasma levels of these markers were measured preoperatively, 6 and 24 h after CBP in 62 patients. Main endpoints were requirements for intra-aortic balloon pump, intensive care unit (ICU) stay longer than five days, ventilator dependence >24 h, requirement for dobutamine, hospital stay >10 days, clinical complications (infection, myocardial infarction, renal failure, stroke and ventricular arrhythmias) and in-hospital mortality. RESULTS: Preoperative BNP levels correlate with longer ICU stay (P = 0.003), longer ventilator use (P = 0.018) and duration of dobutamine use (P < 0.001). The receiver-operating characteristic curve demonstrated BNP levels >190 pg/ml as predictor of ICU >5 days and BNP levels >20.5 pg/ml correlated with dobutamine use, with areas under the curve of 0.712 and 0.842, respectively. Preoperative levels of ICAM-1 were associated with in-hospital mortality (P = 0.042). In the postoperative period, was found association between CRP, IL-6 and P-selectin with ventilation duration (P = 0.013, P = 0.006, P < 0.001, respectively) and P-selectin with ICU stay (P = 0.009). CONCLUSIONS: BNP correlates with clinical endpoints more than inflammatory markers and can be used as a predictor of early outcome after heart surgery.

Reduced expression of systemic proinflammatory and myocardial biomarkers after off-pump versus on-pump coronary artery bypass surgery: a prospective randomized study.

BACKGROUND: The effects of off-pump (OffPCABG) and on-pump (OnPCABG) coronary artery bypass grafting (CABG) on myocardium and inflammation are unclear. OBJECTIVE: Compare the inflammatory response and myocardial injury from patients (pts) submitted to OffPCABG with those that undergo OnPCABG. METHODS: Patients with normal left ventricular function were assigned to OffPCABG (n = 40) and OnPCABG (n = 41). Blood samples were collected before and 24 hours after surgery for determination of creatine kinase (CK)-MB (CK-MB), troponin I (cTnI), interleukin (IL)-6, IL-8, P-selectin, intercellular adhesion molecule (ICAM)-1 and C-reactive protein (CRP). Mortalities were registered at 12 months. RESULTS: Preoperative CK-MB and cTnI levels were 3.1 +/- 0.6 IU and 1.2 +/- 0.5 ng/mL for OffPCABG and 3.0 +/- 0.5 IU and 1.0 +/- 0.2 ng/mL for OnPCABG pts. Postoperative CK-MB and cTnI levels were 13.9 +/- 6.5 IU and 19.0 +/- 9.0 ng/mL for OffPCABG vs 29.5 +/- 11.0 IU and 31.5 +/- 10.1 ng/mL for OnPCABG (P < .01). OffPCABG and OnPCABG pts had similar preoperative IL-6 (10 +/- 7 and 9 +/- 13 pg/mL), IL-8 (19 +/- 7 and 17 +/- 7 pg/mL), soluble P-selectin (70 +/- 21 and 76 +/- 23 pg/mL), soluble ICAM-1 (117 +/- 50 and 127 +/- 52 ng/mL), and CRP (0.09 +/- 0.05 and 0.11 +/- 0.07 mg/L). At 24 hours, for OffPCABG and OnPCABG: IL-6 was 37 +/- 38 and 42 +/- 41 g/mL; IL-8, 33 +/- 31 and 60 +/- 15 pg/mL; soluble P-selectin, 99 +/- 26 and 172 +/- 30 pg/mL; soluble ICAM-1, 227 +/- 47 and 236 +/- 87 ng/mL; and CRP, 10 +/- 11 and 14 +/- 13 mg/L (P < .01 vs preoperation; P < .01 vs OffPCABG). Increased 24-hour postoperative CRP levels was the only marker to have significant positive correlations with events and occurred just for the OnPCABG pts. In-hospital and 1-year mortalities for the OnPCABG and OffPCABG pts were 2.0% and 2.2% (P = .1) and 2.7% and 4.7% (P = .06), respectively. CONCLUSIONS: Thus, the absence of CPB during CABG preserves better the myocardium and attenuates inflammation-however, without improving survival.

Importância da área de fibrose na evolução em médio prazo de pacientes submetidos à reconstrução ventricular / Importance of the area of fibrosis at midterm evolution of patients submitted to ventricular reconstruction / Importancia del área de fibrosis en la evolución a mediano plazo de pacientes sometidos a reconstrucción ventricular

Fundamento: Embora se reconheça que a cirurgia de reconstrução ventricular (CRV) promova remodelamento reverso, são necessários novos estudos para definir a influência da área de fibrose do ventrículo esquerdo (VE). Objetivo: Avaliar se a extensão da área de fibrose do VE é importante na recuperação funcional ventricular após CRV e correlacionar com fatores clínicos. Método: Análise prospectiva de 82 pacientes com disfunção ventricular submetidos à CRV. Analisou-se a importância das características clínicas e foram avaliadas as quantidades de fibrose, mensuradas por ressonância magnética em pequena, média e grande. Resultados: Todos os pacientes foram acompanhados por 36 meses, com mortalidade de 6 por cento. A quantidade de fibrose média foi de 25,8 por cento ± 13,6 por cento. Houve melhora da fração de ejeção do VE (FEVE), de 36,9 por cento ± 6,8 por cento para 48,2 por cento ± 8,2 por cento (p < 0,001). Houve relação inversa entre a quantidade de fibrose o incremento da FEVE (r = -0,83, p < 0,0001). Houve diminuição do volume sistólico final do VE de 43,3 ± 8,2ml/m² (p < 0,001). Houve melhora dos sintomas de insuficiência cardíaca, exceto nos pacientes com grande área de fibrose (p = 0,45). Os preditores independentes para eventos foram: área fibrótica (p = 0,01), idade (p = 0,01), volume sistólico final do VE (p = 0,03) e fração de ejeção (p = 0,02). O seguimento livre de evento foi diferente em relação à área de fibrose (p < 0,01). Conclusão: Em pacientes com disfunção ventricular, a extensão da área fibrótica foi um preditor independente da recuperação funcional do VE após CRV. A combinação de RMC e parâmetros clínicos podem auxiliar na indicação para CRV.

Background: Although it is acknowledged that the ventricular reconstruction surgery (VRS) can promote reverse remodeling, new studies are necessary to define the influence of the left ventricular (LV) area of fibrosis. Objective: To evaluate whether the extension of the area of fibrosis of the LV is important in the LV functional recovery after the surgery and correlate it with clinical factors. Methods: Prospective analysis of 82 patients with ventricular dysfunction submitted to VRS. We analyzed the importance of the clinical characteristics and the amount of fibrosis was assessed, measured by cardiac magnetic resonance (CMR) as small, medium and large. Results: All patients were followed for 36 months, with a mortality of 6 percent. The amount of medium fibrosis was 25.8 percent ± 13.6 percent. There was improvement in the left ventricular ejection fraction (LVEF), from 36.9 percent ± 6.8 percent to 48.2 percent ± 8.2 percent (p < 0.001). There was an inverse association between the amount of fibrosis and the increase in LVEF (r = -0.83, p < 0.0001). There was a decrease in the LV end-systolic volume of 43.3 ± 8.2ml/m² (p < 0.001). There was an improvement in heart failure symptoms, except in patients with large areas of fibrosis (p = 0.45). The independent predictors for events were: fibrotic area (p = 0.01), age (p = 0.01), LV end-systolic volume (p = 0.03) and LVEF (p = 0.02). The event-free follow-up was different in relation to the area of fibrosis (p < 0.01). Conclusion: In patients with ventricular dysfunction, the extension of the area of fibrosis was an independent predictor of the LV functional recovery after the VRS. The combination of cardiac MRI and clinical parameters can help in the indication for VRS.

Fundamento: Si bien se reconoce que la cirugía de reconstrucción ventricular (CRV) promueve remodelación reversa, son necesarios nuevos estudios para definir la influencia del área de fibrosis del ventrículo izquierdo (VE). Objetivo: Evaluar si la extensión del área de fibrosis del VI es importante en la recuperación funcional ventricular tras la CRV y correlacionarlo con factores clínicos. Método: Análisis prospectivo de 82 pacientes con disfunción ventricular sometidos a CRV. Se analizó la importancia de las características clínicas y se evaluaron las áreas de fibrosis, medidas por resonancia magnética y ponderadas como pequeña, mediana y grande. Resultados: Se realizó un seguimiento de 36 meses a todos los pacientes, con mortalidad del 6 por ciento. La cantidad de fibrosis promedio fue del 25,8 por ciento ± 13,6 por ciento. Existió una mejora de la fracción de eyección del VI (FEVI), del 36,9 por ciento ± 6,8 por ciento al 48,2 por ciento ± 8,2 por ciento (p < 0,001). Existió relación inversa entre la cantidad de fibrosis y el incremento de la FEVI (r = -0,83, p < 0,0001). Hubo una disminución del volumen de fin de sístole del VI de 43,3 ± 8,2ml/m² (p < 0,001). Se produjo una mejoría en los síntomas de insuficiencia cardiaca, excepto en los pacientes con gran área de fibrosis (p = 0,45). Los predictores independientes para eventos fueron: área de fibrosis (p = 0,01), edad (p = 0,01), volumen de fin de sístole del VI (p = 0,03) y fracción de eyección (p = 0,02). El seguimiento libre de eventos fue diferente en relación con el área de fibrosis (p < 0,01). Conclusión: En pacientes con disfunción ventricular, la extensión del área de fibrosis fue un predictor independiente de la recuperación funcional del VI luego de la CRV. La combinación de RMC y parámetros clínicos puede auxiliar en la indicación de CRV.

Importance of the area of fibrosis at midterm evolution of patients submitted to ventricular reconstruction.

BACKGROUND: Although it is acknowledged that the ventricular reconstruction surgery (VRS) can promote reverse remodeling, new studies are necessary to define the influence of the left ventricular (LV) area of fibrosis. OBJECTIVE: To evaluate whether the extension of the area of fibrosis of the LV is important in the LV functional recovery after the surgery and correlate it with clinical factors. METHODS: Prospective analysis of 82 patients with ventricular dysfunction submitted to VRS. We analyzed the importance of the clinical characteristics and the amount of fibrosis was assessed, measured by cardiac magnetic resonance (CMR) as small, medium and large. RESULTS: All patients were followed for 36 months, with a mortality of 6%. The amount of medium fibrosis was 25.8% +/- 13.6%. There was improvement in the left ventricular ejection fraction (LVEF), from 36.9% +/- 6.8% to 48.2% +/- 8.2% (p < 0.001). There was an inverse association between the amount of fibrosis and the increase in LVEF (r = -0.83, p < 0.0001). There was a decrease in the LV end-systolic volume of 43.3 +/- 8.2 ml/m(2) (p < 0.001). There was an improvement in heart failure symptoms, except in patients with large areas of fibrosis (p = 0.45). The independent predictors for events were: fibrotic area (p = 0.01), age (p = 0.01), LV end-systolic volume (p = 0.03) and LVEF (p = 0.02). The event-free follow-up was different in relation to the area of fibrosis (p < 0.01). CONCLUSION: In patients with ventricular dysfunction, the extension of the area of fibrosis was an independent predictor of the LV functional recovery after the VRS. The combination of cardiac MRI and clinical parameters can help in the indication for VRS.

Serial changes in plasma levels of cytokines in patients with coronary artery disease.

OBJECTIVES: Inflammation is known to be a major determinant of the progression of coronary artery disease (CAD). In the present study we have evaluated the plasma levels of cytokines-tumor necrosis factor-alpha (TNF), interleukin- 1 alpha (IL-1), interleukin-6 (IL-6), interferon-gamma (IFN), and interleukin-10 (IL-10)- to examine the association between these cytokines and C-reactive protein (CRP) in patients with CAD. METHODS: Patients with acute coronary syndromes (ACS; n = 20) were compared with patients with stable angina (SA; n= 20) and with control volunteers (C; n= 20). Blood samples were collected at the time of admission from all patients and 15 and 30 days thereafter. RESULTS: CRP levels (20.8+/-8.8 mg/L) (mean+/-SEM) were higher at baseline in ACS than SA patients (4.1+/-0.8mg/L) or the control subjects (5.1+/-1.8mg/L) (p<0.05). At admission, IL-6 was detected in 50% of the ACS patients and 5% of the SA patients or control subjects, while TNF was detected in 35% of the ACS and SA patients but only in 5% of control subjects. Subsequently, IL-6 levels declined and were no longer detectable, while TNF levels increased among ACS patients at all time periods tested when compared with other patients. The presence of IL-1 and IL-10 were not detectable in the blood samples examined, and IFN could only be detected in the ACS group. A significant correlation was observed between IL-6 and CRP levels (r=0.4; p<0.01) in all groups. There were no correlations among any of the other cytokines and CRP levels. CONCLUSIONS: Our study demonstrates raised levels of TNF, IL-6, IFN, and CRP in patients with ACS and a positive correlation between IL-6 and CRP but not with the other cytokines.