Diabetic cardiomyopathy is a secondary complication of diabetes with an unclear etiology. Based on a functional genomic evaluation of obesity-associated cardiac gene expression, we previously identified and cloned the gene encoding apolipoprotein O (APOO), which is overexpressed in hearts from diabetic patients. Here, we generated APOO-Tg mice, transgenic mouse lines that expresses physiological levels of human APOO in heart tissue. APOO-Tg mice fed a high-fat diet exhibited depressed ventricular function with reduced fractional shortening and ejection fraction, and myocardial sections from APOO-Tg mice revealed mitochondrial degenerative changes. In vivo fluorescent labeling and subcellular fractionation revealed that APOO localizes with mitochondria. Furthermore, APOO enhanced mitochondrial uncoupling and respiration, both of which were reduced by deletion of the N-terminus and by targeted knockdown of APOO. Consequently, fatty acid metabolism and ROS production were enhanced, leading to increased AMPK phosphorylation and Ppara and Pgc1a expression. Finally, we demonstrated that the APOO-induced cascade of events generates a mitochondrial metabolic sink whereby accumulation of lipotoxic byproducts leads to lipoapoptosis, loss of cardiac cells, and cardiomyopathy, mimicking the diabetic heart-associated metabolic phenotypes. Our data suggest that APOO represents a link between impaired mitochondrial function and cardiomyopathy onset, and targeting APOO-dependent metabolic remodeling has potential as a strategy to adjust heart metabolism and protect the myocardium from impaired contractility.
This study sought to phenotype patients over 65 years old with heart failure and preserved ejection fraction (HFpEF) using clinical available comprehensive cardiovascular imaging modalities. Forty-nine patients with HFpEF and without coronary artery disease underwent clinical evaluation, electrocardiography, echocardiography, cardiac magnetic resonance (CMR) and Tc-3,3-diphosphono-1,2-propanodicarboxylic acid scintigraphy (Tc-DPD). The mean population age was 76 ± 8 years. Most of the patients (53 %) were NYHA class II. Mean NT-Pro-NBNP level was 1961 ± 2372 pg/ml. CMR exhibited a hypertrophic cardiomyopathy or infiltrative pattern in 3 (6 %) and 15 (31 %) patients, respectively. In the latter subgroup, Tc-DPD was suggestive of transthyretin-related cardiac amyloidosis for nine (18 %) patients, while AL amyloidosis was proven in five patients (10 %) by extracardiac (n = 3, 6 %) or endomyocardial (n = 2, 4 %) biopsies-one patient declined tissue biopsy. Compared to patients with unspecified cardiomyopathy (n = 31), patients with amyloid cardiomyopathy (n = 15 or n = 14/proven) had less hypertension, lower systolic blood pressure and higher NT-pro BNP level. Their electrocardiogram showed lowest QRS voltage and longer QRS duration. Left ventricular (LV) pattern was characterized by a more pronounced LV hypertrophy, a smaller ejection fraction and a decrease of global longitudinal strain associated with an increase of longitudinal strain apical-to-basal ratio. In patients over 65 years, HFpEF is a heterogeneous syndrome with at least a 29 % prevalence of amyloid cardiomyopathy. Combined CMR andTc-DPD are helpful imaging tools for accurate phenotyping of patients amenable to histopathological diagnosis or genetic testing, and should be considered for proper management of this population. Further longitudinal investigations are needed to better clarify these preliminary results.
AimsAlthough dipyridamole is a widely used pharmacological stress agent, the direct effects on myocardium are not entirely known. Diabetic cardiomyopathy can be investigated by 2D-strain echocardiography. The aim of this study was to assess myocardial functional reserve after dipyridamole infusion using speckle-tracking echocardiography.MethodsSeventy-five patients referred for dipyridamole stress myocardial perfusion gated SPECT (MPGS) were examined by echocardiography to assess a new concept of longitudinal strain reserve (LSR) and longitudinal strain rate reserve (LSRR) respectively defined by the differences of global longitudinal strain (GLS) and longitudinal strain rate between peak stress after dipyridamole and rest. Twelve patients with myocardial ischemia were excluded on the basis of MPGS as gold standard.ResultsMean LSR was −2.28±2.19% and was more important in the 28 (44%) diabetic patients (−3.27±1.93%; p = 0.001). After multivariate analyses, only diabetes improved LSR (p = 0.011) after dipyridamole infusion and was not associated with glycaemic control (p = 0.21), insulin therapy (p = 0.46) or duration of the disease (p = 0.80). Conversely, age (p = 0.002) remained associated with a decrease in LSR. LSSR was also correlated to age (p = 0.005). Patients with a LSR < 0% have a better survival after 15 months (log-rank p = 0.0012).ConclusionLSR explored by 2D speckle-tracking echocardiography after dipyridamole infusion is a simple and new concept that provides new insights into the impact of diabetes and age on the myocardium with a potential prognostic value.
ObjectiveMortality in heart failure (AHF) remains high, especially during the first days of hospitalization. New prognostic biomarkers may help to optimize treatment. The aim of the study was to determine metabolites that have a high prognostic value.MethodsWe conducted a prospective study on a training cohort of AHF patients (n = 126) admitted in the cardiac intensive care unit and assessed survival at 30 days. Venous plasmas collected at admission were used for 1H NMR
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based metabonomics analysis. Differences between plasma metabolite profiles allow determination of discriminating metabolites. A cohort of AHF patients was subsequently constituted (n = 74) to validate the findings.ResultsLactate and cholesterol were the major discriminating metabolites predicting 30-day mortality. Mortality was increased in patients with high lactate and low total cholesterol concentrations at admission. Accuracies of lactate, cholesterol concentration and lactate to cholesterol (Lact/Chol) ratio to predict 30-day mortality were evaluated using ROC analysis. The Lact/Chol ratio provided the best accuracy with an AUC of 0.82 (P < 0.0001). The acute physiology and chronic health evaluation (APACHE) II scoring system provided an AUC of 0.76 for predicting 30-day mortality. APACHE II score, Cardiogenic shock (CS) state and Lact/Chol ratio ≥ 0.4 (cutoff value with 82% sensitivity and 64% specificity) were significant independent predictors of 30-day mortality with hazard ratios (HR) of 1.11, 4.77 and 3.59, respectively. In CS patients, the HR of 30-day mortality risk for plasma Lact/Chol ratio ≥ 0.4 was 3.26 compared to a Lact/Chol ratio of < 0.4 (P = 0.018). The predictive power of the Lact/Chol ratio for 30-day mortality outcome was confirmed with the independent validation cohort.ConclusionThis study identifies the plasma Lact/Chol ratio as a useful objective and simple parameter to evaluate short term prognostic and could be integrated into quantitative guidance for decision making in heart failure care.
Background: Diagnostic biomarkers for heart failure (HF) such as the natriuretic peptides (NPs) are widely used but have limitations. Innovative biomarkers could provide improved diagnostic performance. Methods: We launched a prospective case-control proteomic study and investigated for polypeptides specific to HF through a capillary electrophoresis-mass spectrometry (CE-MS) proteomic analysis. The putative biomarker was identified by Orbitrap liquid chromatography-MS, validated by western blot, then by ELISA using plasmas from multicentric international cohorts. A rat model of HF was tested for biomarker expression levels. Results: We identified insulin like growth factor binding protein 2 (IGFBP2) as a new diagnostic biomarker for HF with a high sensitivity and specificity (AUC = 0.93; 95% CI, 0.89-0.96; p b 0.0001) in the local cohort and IGFBP2 levels provided an AUC of 0.943 (95% CI, 0.860-1.026) which gave a 87 % sensitivity in AHF and 90 % specificity at the cut off value previously determined in the discovery cohort, i.e. 556 ng/ml. ROC curve analysis of IGFBP2 and NTproBNP showed an AUC of 0.784 (95% CI, 0.744-0.820) for IGFBP2 and a significantly higher AUC of 0.927 (95% CI, 0.900-0.949) for NT-proBNP, p b 0.0001 in a Dutch cohort. In this cohort, the optimal cut off value for IGFBP2 gave a sensibility of 71% (95% CI, 66-76) and a specificity of 75% (95% CI, 65-83). Conclusion: IGFBP2 is a new biomarker to diagnose HF which could be used to provide additional information to the NPs. Animals models will help in the evaluation of the putative IGFBP2 regulated mechanisms in HF. Clinical Trial Registration: ClinicalTrials.gov NCT01024049.
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