José Roberto Matos Souza

Targeting Focal Adhesion Kinase With Small Interfering RNA Prevents and Reverses Load-Induced Cardiac Hypertrophy in Mice

Hypertrophy is a critical event in the onset of failure in chronically overloaded hearts. Focal adhesion kinase (FAK) has attracted particular attention as a mediator of hypertrophy induced by increased load. Here, we demonstrate increased expression and phosphorylation of FAK in the hypertrophic left ventricles (LVs) of aortic-banded mice. We used an RNA interference strategy to examine whether FAK signaling plays a role in the pathophysiology of load-induced LV hypertrophy and failure. Intrajugular delivery of specific small interfering RNA induced prolonged FAK silencing (≈70%) in both normal and hypertrophic LVs. Myocardial FAK silencing was accompanied by prevention, as well as reversal, of load-induced left ventricular hypertrophy. The function of LVs was preserved and the survival rate was higher in banded mice treated with small interfering RNA targeted to FAK, despite the persistent pressure overload. Studies in cardiac myocytes and fibroblasts harvested from LVs confirmed the ability of the systemically administered specific small interfering RNA to silence FAK in both cell types. Further analysis indicated attenuation of cardiac myocyte hypertrophic growth and of the rise in the expression of β-myosin heavy chain in overloaded LVs. Moreover, FAK silencing was demonstrated to attenuate the rise in the fibrosis, collagen content, and activity of matrix metalloproteinase-2 in overloaded LVs, as well as the rise of matrix metalloproteinase-2 protein expression in fibroblasts harvested from overloaded LVs. This study provides novel evidence that FAK may be involved in multiple aspects of the pathophysiology of cardiac hypertrophy and failure induced by pressure overload.

TyG index performs better than HOMA in a Brazilian population: A hyperglycemic clamp validated study

The TyG index was evaluated as a surrogate method for estimation of insulin resistance (IR). TyG index correlated with adiposity, metabolic and atherosclerosis markers related to IR and presented a moderate degree of agreement with hyperglycemic clamp. TyG index represents an accessible tool for assessment of IR in clinical practice.

Níveis séricos de interleucina-6 (IL-6), interleucina-18 (IL-18) e proteína C reativa (PCR) na síndrome coronariana aguda sem supradesnivelamento do ST em pacientes com diabete tipo 2

BACKGROUND Atherosclerosis is an inflammatory disease, and serum levels of inflammatory markers such as interleukin 6 (IL-6), interleukin 18 (IL-18) and C-reactive protein (CRP) are used to evaluate patients with coronary artery disease. In patients with type-2 diabetes, atherosclerosis is related to a larger number of events such as myocardial infarction and death, when compared with patients without diabetes. OBJECTIVE To evaluate the inflammatory response in patients with diabetes and acute events of coronary instability. METHODS Two groups of patients were primarily selected. The first group was comprised of diabetic outpatients with stable angina (D-CCS) and presence of coronary artery disease on coronary angiography (n=36). The second group was comprised of diabetic patients seen in the emergency room with acute coronary syndrome (D-ACS) without ST-segment elevation (n=38). Non-diabetic patients with ACS (n=22) and CCS (n=16) comprised the control group. Serum levels of CRP, IL-6 and IL-18 were determined using nephelometry (CRP) and ELISA (IL-6 and IL-18) techniques. RESULTS Higher serum IL-6 levels were found in diabetic or non-diabetic patients with ACS than in the group with CCS. On the other hand, diabetic patients with ACS had higher CRP levels in comparison with the other groups. Serum IL-18 levels were not significantly different among the patients studied. CONCLUSION our findings suggest a more intense inflammatory activity in patients with coronary instability. This inflammatory activity, as measured by CRP, seems to be even more intense in diabetic patients.

MEF2C Silencing Attenuates Load-Induced Left Ventricular Hypertrophy by Modulating mTOR/S6K Pathway in Mice

Background The activation of the members of the myocyte enhancer factor-2 family (MEF2A, B, C and D) of transcription factors promotes cardiac hypertrophy and failure. However, the role of its individual components in the pathogenesis of cardiac hypertrophy remains unclear. Methodology/Principal Findings In this study, we investigated whether MEF2C plays a role in mediating the left ventricular hypertrophy by pressure overload in mice. The knockdown of myocardial MEF2C induced by specific small interfering RNA (siRNA) has been shown to attenuate hypertrophy, interstitial fibrosis and the rise of ANP levels in aortic banded mice. We detected that the depletion of MEF2C also results in lowered levels of both PGC-1α and mitochondrial DNA in the overloaded left ventricle, associated with enhanced AMP:ATP ratio. Additionally, MEF2C depletion was accompanied by defective activation of S6K in response to pressure overload. Treatment with the amino acid leucine stimulated S6K and suppressed the attenuation of left ventricular hypertrophy and fibrosis in the aforementioned aortic banded mice. Conclusion/Significance These findings represent new evidences that MEF2C depletion attenuates the hypertrophic responses to mechanical stress and highlight the potential of MEF2C to be a target for new therapies to cardiac hypertrophy and failure.

Differential expression of cytokines, chemokines and chemokine receptors in patients with coronary artery disease.

Monocytes/macrophages and lymphocytes have a key role in the pathogenesis of atherosclerosis through the production of inflammatory and anti-inflammatory cytokines. We evaluated mRNA expression and protein production of CCL2, CXCL8, CXCL9, CXCL10, IFN-gamma and IL-10 in vitro as well as the expression of the CCR2 and CXCR3 receptors in peripheral blood mononuclear cells (PBMCs) of patients with coronary artery disease (CAD) and healthy controls in the presence or absence of oxidized LDL (oxLDL). Patients with CAD showed higher constitutive expression of CCL2, CXCL8, CXCL9, CXCL10 and IFN-gamma mRNA and, after stimulation with oxLDL, higher expression of CCL2 and CXCL8 mRNA than the control group. We also detected higher levels of CCL2 and CXCL8 in supernatants of oxLDL-stimulated PBMCs from CAD patients than in corresponding supernatants from controls. Patients with CAD had a higher percentage of constitutive CCR2(+) and CXCR3(+) cells after stimulation with oxLDL. Among CAD patients, the main differences between the stable (SA) and unstable angina (UA) groups were lower IL-10 mRNA production in the latter group. Altogether, our data suggest that PBMCs from CAD patients are able to produce higher concentrations of chemokines and cytokines involved in the regulation of monocyte and lymphocyte migration and retention in atherosclerotic lesions.

Genótipos de haptoglobina e hipertensão refratária em pacientes com diabete melito tipo 2

BACKGROUND It has been suggested that haptoglobin polymorphism may influence the pathogenesis of microvascular and macrovascular complications in diabetic patients. OBJECTIVE This cross sectional study was carried out to investigate the existence or not of an association between haptoglobin genotypes and prevalence of ischemic cardiovascular events (stable angina, unstable angina and acute myocardial infarction), systemic arterial hypertension, refractory hypertension, obesity and dyslipidemia in 120 type-2 diabetes mellitus patients followed up at Hospital de Clínicas da UNICAMP in Campinas, São Paulo state, southeastern Brazil. METHODS Haptoglobin genotyping was performed by allele-specific polymerase chain reactions. The frequencies of the haptoglobin genotypes were compared with the presence/absence of cardiovascular disease, systemic arterial hypertension, refractory hypertension, obesity and dyslipidemia; systolic and diastolic blood pressure measurements; plasma levels of glucose, cholesterol (total, high density lipoprotein-HDL and low density lipoprotein-LDL) and triglycerides; and serum creatinine levels. RESULTS Although no association between haptoglobin genotype and the presence of cardiovascular disease could be identified, we found a significant excess of patients with Hp2-1 genotype among those with refractory hypertension, who also had higher systolic and diastolic blood pressure, and total and LDL cholesterol levels. CONCLUSION Our results suggest that type-2 diabetes mellitus patients with the Hp2-1 genotype may have higher chances of developing refractory hypertension. Further studies in other diabetic populations are required to confirm these findings.FUNDAMENTO: Tem sido sugerido que o polimorfismo da haptoglobina pode influenciar na patogenese das complicacoes microvasculares e macrovasculares em pacientes diabeticos. OBJETIVO: O objetivo principal deste estudo transversal foi de realizar uma investigacao da existencia ou nao de uma associacao entre os genotipos de haptoglobina e a prevalencia de eventos isquemicos cardiovasculares (angina estavel, angina instavel e infarto agudo do miocardio), hipertensao arterial sistemica, hipertensao refrataria, obesidade e dislipidemia em 120 pacientes com diabete melito tipo 2, seguidos no Hospital Universitario da Unicamp, em Campinas, Estado de Sao Paulo. METODOS: A genotipagem da haptoglobina foi realizada por reacoes em cadeia da polimerase alelo-especificas. As frequencias dos genotipos de haptoglobina foram comparadas com a presenca/ausencia de doenca cardiovascular, hipertensao arterial sistemica, hipertensao refrataria, obesidade e dislipidemia; medicoes de pressao arterial sistolica e diastolica; glicemia, colesterol (total, lipoproteinas de alta densidade - HDL e lipoproteinas de baixa densidade - LDL) e triglicerideos; assim como niveis de creatinina serica. RESULTADOS: Embora nenhuma associacao entre o genotipo de haptoglobina e a presenca de doenca cardiovascular tenha sido identificada, encontramos um excesso significativo de pacientes com o genotipo Hp2-1 entre as pessoas com hipertensao refrataria, que tambem apresentavam uma maior pressao arterial sistolica e diastolica e niveis de colesterol total e LDL. CONCLUSAO: Nossos resultados sugerem que os pacientes com diabete melito tipo 2 com o genotipo Hp2-1 podem apresentar uma maior chance de desenvolver hipertensao refrataria. Estudos adicionais em populacoes diabeticas sao necessarios para confirmar esses achados.

Sagittal abdominal diameter as a marker for epicardial adipose tissue in premenopausal women

OBJECTIVE Accumulation of epicardial (EAT) adipose tissue is associated with the development of an unfavorable metabolic risk profile. Gold standard methods used to assess this fat depot are not routinely applicable in the clinic. Anthropometric measures, including the sagittal abdominal diameter (SAD), have emerged as surrogate markers of visceral obesity. We determined the relationship between EAT measurement and cardiometabolic risk parameters and the potential use of the SAD, compared with other anthropometric parameters, as a practical estimation of EAT. MATERIALS/METHODS Sixty-seven premenopausal women were evaluated. The anthropometric parameters that were measured included waist circumference, SAD, body mass index and waist-to-hip ratio. EAT was determined by echocardiogram. Visceral adipose tissue (VAT) was determined by abdominal ultrasound. Insulin sensitivity was assessed by the hyperglycemic clamp. RESULTS The accumulation of EAT was correlated with impaired insulin sensitivity and decreased adiponectin. All of the anthropometric measurements were correlated with EAT. Interestingly, EAT was most significantly correlated with the SAD. From the ROC analysis, we found that the SAD measurements were very accurate, presenting the highest area under the curve for EAT (0.81; p<0.01) when compared with the other measurements. In the multiple linear regression analysis, EAT was moderately predicted by the SAD (R²=0.25; p<0.001). CONCLUSION SAD, a simple anthropometric measure, accurately estimated EAT and thus represents a clinically useful non-invasive marker that can identify patients with EAT accumulation.

P-wave duration is a predictor for long-term mortality in post-CABG patients

Risk stratification in secondary prevention has emerged as an unmet clinical need in order to mitigate the Number-Needed-to-Treat and make expensive therapies both clinically relevant and cost-effective. P wave indices reflect atrial conduction, which is a sensitive marker for inflammatory, metabolic, and pressure overload myocardial cell remodeling; the three stimuli are traditional mechanisms for adverse clinical evolution. Accordingly, we sought to investigate the predictive role of P-wave indices to estimate residual risk in patients with chronic coronary artery disease (CAD). The cohort included 520 post-Coronary Artery Bypass Grafting patients with a median age of 60 years who were followed for a median period of 1025 days. The primary endpoint was long-term all-cause death. Cubic spline model demonstrated a linear association between P-wave duration and incidence rate of long-term all-cause death (p = 0.023). P-wave >110ms was a marker for an average of 425 days shorter survival as compared with P-wave under 80ms (Logrank p = 0.020). The Cox stepwise regression models retained P-wave duration as independent marker (HR:1.37; 95%CI:1.05–1.79,p = 0.023). In conclusion, the present study suggests that P-wave measurement may constitute a simple, inexpensive and accessible prognostic tool to be added in the bedside risk estimation in CAD patients.