Cardiac iron concentration in relation to systemic iron status and disease severity in non-ischaemic heart failure with reduced ejection fraction.

AIMS: Low cardiac iron levels promote heart failure in experimental models. While cardiac iron concentration (CI) is decreased in patients with advanced heart failure with reduced ejection fraction (HFrEF), CI has never been measured in non-advanced HFrEF. We measured CI in left ventricular (LV) endomyocardial biopsies (EMB) from patients with non-advanced HFrEF and explored CI association with systemic iron status and disease severity. METHODS AND RESULTS: We enrolled 80 consecutive patients with non-ischaemic HFrEF with New York Heart Association class II or III symptoms and a median (interquartile range) LV ejection fraction of 25 (18-33)%. CI was 304 (262-373) µg/g dry tissue. CI was not related to immunohistological findings or the presence of cardiotropic viral genomes in EMBs and was not related to biomarkers of systemic iron status or anaemia. Patients with CI in the lowest quartile (CIQ1 ) had lower body mass indices and more often presented with heart failure histories longer than 6 months than patients in the upper three quartiles (CIQ2-4 ). CIQ1 patients had higher serum N-terminal pro-B-type natriuretic peptide levels than CIQ2-4 patients [3566 (1513-6412) vs. 1542 (526-2811) ng/L; P = 0.005]. CIQ1 patients also had greater LV end-diastolic (P = 0.001) and end-systolic diameter indices (P = 0.003) and higher LV end-diastolic pressures (P = 0.046) than CIQ2-4 patients. CONCLUSION: Low CI is associated with greater disease severity in patients with non-advanced non-ischaemic HFrEF. CI is unrelated to systemic iron homeostasis. The prognostic and therapeutic implications of CI measurements in EMBs should be further explored.

Diagnostic and prognostic value of sex- and age-specific cutpoints for high-sensitivity Troponin T in non-ST-elevation acute coronary syndrome.

INTRODUCTION: Sex- and age-specific high-sensitivity Troponin T (hs-cTnT) cutpoints for the diagnosis and prognosis in acute coronary syndromes are not well established. We evaluated the use of such dichotomous thresholds for calculation of the GRACE score. METHODS: We analyzed a retrospective cohort study of 1146 patients with non-ST-elevation acute coronary syndrome (NSTE-ACS). Sex-dependent hs-cTnT cutpoints comprised 15.5 ng/L for men and 9.0 ng/L for women, while the sex-/age-specific cutpoints comprised 17 ng/L for 50-64-year-old men and ≥65-year-old women, 31 ng/L for ≥65-year-old men and 14 ng/L for the remainder of patients. RESULTS: For the diagnosis of NSTEMI using sex-specific hs-cTnT cutpoints, in women, the positive likelihood ratio (LR+) was 2.04 (1.68-2.47) while in men, the negative likelihood ratio (LR-) was 0.05 (0.04-0.07). Using sex-/age-specific hs-cTnT cutpoints, in ≥65-year-old women the LR- was 0.09 (0.06-0.15), in 50 to 64-year-old men the LR- was 0.08 (0.04-0.13) while in ≥65-year-old men the LR- was 0.32 (0.28-0.37). Sex-specific hs-cTnT cutpoints achieved an NRI of -0.020 (95% CI, -0.101-0.118) for women and 0.030 (95% CI, -0.013-0.079) for men, and the sex-/age-specific hs-cTnT cutpoints achieved an NRI of 0.061 (95% CI, -0.019-0.132) for women and 0.021 (95% CI, -0.062-0.108) for men, while net benefit and clinical utility were highest for women using the sex-/age-specific hs-cTnT cutpoints. CONCLUSIONS: Sex-dependent hs-cTNT cutpoints imply increasing diagnostic sensitivity for women at the cost of specificity. Considering age for hs-cTNT cutoffs slightly improves risk reclassification, although the overall gain in terms of the clinical management appears negligible.

Growth-differentiation factor 15 for long-term prognostication in patients with non-ST-elevation acute coronary syndrome: an Invasive versus Conservative Treatment in Unstable coronary Syndromes (ICTUS) substudy.

BACKGROUND: No five-year long-term follow-up data is available regarding the prognostic value of GDF-15. Our aim is to evaluate the long-term prognostic value of admission growth-differentiation factor 15 (GDF-15) regarding death or myocardial infarction (MI) in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS). METHODS: This is a subanalysis from the ICTUS (Invasive versus Conservative Treatment in Unstable coronary Syndromes) trial, including troponin positive NSTE-ACS patients. The main outcome for the current analysis was 5-year death or spontaneous MI. GDF-15 samples were available in 1151 patients. The prognostic value of GDF-15, categorized into <1200 ng/L, 1200-1800 ng/L and >1800 ng/L, was assessed in unadjusted and adjusted Cox regression models. Adjustments were made for identified univariable risk factors. The additional discriminative and reclassification value of GDF-15 beyond the independent risk factors was assessed by the category-free net reclassification improvement (1/2 NRI(>0)) and the integrated discrimination improvement (IDI) RESULTS: Compared to GDF-15<1200 ng/L, a GDF-15>1800 ng/L was associated with an increased hazard ratio for death or spontaneous MI, mainly driven by mortality. GDF-15 levels were predictive after adjustments for other identified predictors. Additional discriminative value was shown with the IDI, not with the NRI. CONCLUSION: In patients presenting with NSTE-ACS and elevated troponin T, GDF-15 provides prognostic information in addition to identified predictors for mortality and spontaneous MI and can be used to identify patients at high risk during long-term follow-up.

Incremental prognostic value of biomarkers beyond the GRACE (Global Registry of Acute Coronary Events) score and high-sensitivity cardiac troponin T in non-ST-elevation acute coronary syndrome.

BACKGROUND: Guidelines recommend the use of validated risk scores and a high-sensitivity cardiac troponin assay for risk assessment in non-ST-elevation acute coronary syndrome (NSTE-ACS). The incremental prognostic value of biomarkers in this context is unknown. METHODS: We calculated the Global Registry of Acute Coronary Events (GRACE) score and measured the circulating concentrations of high-sensitivity cardiac troponin T (hs-cTnT) and 8 selected cardiac biomarkers on admission in 1146 patients with NSTE-ACS. We used an hs-cTnT threshold at the 99th percentile of a reference population to define increased cardiac marker in the score. The magnitude of the increase in model performance when individual biomarkers were added to GRACE was assessed by the change (Δ) in the area under the receiver-operating characteristic curve (AUC), integrated discrimination improvement (IDI), and category-free net reclassification improvement [NRI(>0)]. RESULTS: Seventy-eight patients reached the combined end point of 6-month all-cause mortality or nonfatal myocardial infarction. The GRACE score alone had an AUC of 0.749. All biomarkers were associated with the risk of the combined end point and offered statistically significant improvement in model performance when added to GRACE (likelihood ratio test P ≤ 0.015). Growth differentiation factor 15 [ΔAUC 0.039, IDI 0.049, NRI(>0) 0.554] and N-terminal pro-B-type natriuretic peptide [ΔAUC 0.024, IDI 0.027, NRI(>0) 0.438] emerged as the 2 most promising biomarkers. Improvements in model performance upon addition of a second biomarker were small in magnitude. CONCLUSIONS: Biomarkers can add prognostic information to the GRACE score even in the current era of high-sensitivity cardiac troponin assays. The incremental information offered by individual biomarkers varies considerably, however.

Growth differentiation factor 15 predicts future insulin resistance and impaired glucose control in obese nondiabetic individuals: results from the XENDOS trial.

OBJECTIVE: Growth differentiation factor-15 (GDF-15) is a stress-responsive cytokine that is increased in obesity and established type 2 diabetes. We assessed whether GDF-15 can predict future insulin resistance and impaired glucose control in obese nondiabetic individuals. DESIGN AND METHODS: Plasma GDF-15 concentrations were measured with an automated electrochemiluminescent immunoassay at baseline and after 4 years in 496 obese nondiabetic individuals (52% men, median age 48 years, median body mass index (BMI) 37.6 kg/m(2)) enrolled in the XENical in the prevention of Diabetes in Obese subjects (XENDOS) trial. RESULTS: The median GDF-15 concentration at baseline was 869 ng/l (interquartile range 723-1064 ng/l). GDF-15 was related to body weight, BMI, waist-to-hip ratio, and insulin resistance (homeostasis model assessment of insulin resistance (HOMA-IR)) (all P < 0.01). Changes in GDF-15 from baseline to 4 years were related to changes in body weight, BMI, waist-to-hip ratio, and HOMA-IR (all P < 0.05). Baseline GDF-15 was associated with the risk to have prediabetes or diabetes at 4 years by univariate analysis (odds ratio (OR) FOR 1 unit increase in ln GDF-15, 3.2; 95% confidence interval (CI): 1.7-6.1; P<0.001), and after multivariate adjustment for age, gender, treatment allocation (orlistat vs placebo), BMI, waist-to-hip ratio, and glucose control at baseline (OR 2.2; 95% CI: 1.1-4.7; P=0.026). Similarly, baseline GDF-15 was independently associated with HOMA-IR at 4 years (P=0.024). CONCLUSIONS: This first longitudinal study of GDF-15 in a large cohort of obese individuals indicates that GDF-15 is related to abdominal obesity and insulin resistance and independently associated with future insulin resistance and abnormal glucose control.

Growth-differentiation factor-15 for risk stratification in patients with stable and unstable coronary heart disease: results from the AtheroGene study.

BACKGROUND: Growth-differentiation factor-15 (GDF-15) is a stress-responsive transforming growth factor-beta-related cytokine that has emerged as a prognostic biomarker in acute coronary syndrome trial populations. Its predictive role in stable coronary heart disease (CHD) has never been assessed. METHODS AND RESULTS: The circulating levels of GDF-15 were measured by immunoradiometric assay in patients with stable angina pectoris (n=1352) or acute coronary syndrome (n=877) who were followed up for a median of 3.6 years. Stable angina pectoris patients presenting with normal (<1200 ng/L), moderately elevated (1200 to 1800 ng/L), or markedly elevated (>1800 ng/L) GDF-15 levels had 3.6-year CHD mortality rates of 1.4%, 2.7%, and 15.0%, respectively (P<0.001). By backward stepwise Cox-regression analysis, which adjusted for age and gender, clinical variables, the number of diseased vessels, renal function, the levels of C-reactive protein, cardiac troponin I, and N-terminal pro-B-type natriuretic peptide, GDF-15 remained an independent predictor of CHD mortality (P<0.001). Addition of GDF-15 improved the prognostic accuracy of a clinical risk prediction model concerning CHD mortality (c-statistic, 0.84 versus 0.74; P=0.005). Analysis of the acute coronary syndrome part of the study population confirmed GDF-15 as an independent predictor of CHD mortality (P<0.001). The circulating levels of GDF-15 did not predict the future risk of nonfatal myocardial infarction in patients with stable angina pectoris or acute coronary syndrome. CONCLUSIONS: This study identifies GDF-15 as a strong and independent predictor of CHD mortality across the broad spectrum of patients with stable and unstable CHD.

Growth-differentiation factor-15 is an independent marker of cardiovascular dysfunction and disease in the elderly: results from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) Study.

AIMS: Growth-differentiation factor-15 (GDF-15) is emerging as an independent prognostic biomarker in patients with cardiovascular (CV) disease. Little is known about the pathophysiological basis for the close association of GDF-15 to future CV events. We hypothesized that GDF-15 is related to underlying CV pathologies. METHODS AND RESULTS: To relate the levels of GDF-15 to indices of CV dysfunction and disease in elderly individuals, serum levels of GDF-15 were measured in 1004 subjects aged 70 years from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. Carotid intima-media thickness and plaque burden, and left ventricular (LV) geometry and function were assessed by ultrasound. Endothelial function was evaluated in forearm resistance vessels and in the brachial artery by venous occlusion plethysmography and ultrasound imaging, respectively. Elevated levels of GDF-15 were related to several CV risk factors (male gender, current smoking, body mass index, waist circumference, diabetes, fasting glucose, triglycerides, and low HDL cholesterol). After adjustment for CV risk factors, increased levels of GDF-15 were associated with reduced endothelium-dependent vasodilation in resistance vessels, plaque burden, LV mass and concentric LV hypertrophy, reduced LV ejection fraction, and clinical manifestations of coronary artery disease and heart failure. CONCLUSION: GDF-15 carries information on CV dysfunction and disease that is not captured by traditional CV risk factors in elderly individuals.

A cathepsin D-cleaved 16 kDa form of prolactin mediates postpartum cardiomyopathy.

Postpartum cardiomyopathy (PPCM) is a disease of unknown etiology and exposes women to high risk of mortality after delivery. Here, we show that female mice with a cardiomyocyte-specific deletion of stat3 develop PPCM. In these mice, cardiac cathepsin D (CD) expression and activity is enhanced and associated with the generation of a cleaved antiangiogenic and proapoptotic 16 kDa form of the nursing hormone prolactin. Treatment with bromocriptine, an inhibitor of prolactin secretion, prevents the development of PPCM, whereas forced myocardial generation of 16 kDa prolactin impairs the cardiac capillary network and function, thereby recapitulating the cardiac phenotype of PPCM. Myocardial STAT3 protein levels are reduced and serum levels of activated CD and 16 kDa prolactin are elevated in PPCM patients. Thus, a biologically active derivative of the pregnancy hormone prolactin mediates PPCM, implying that inhibition of prolactin release may represent a novel therapeutic strategy for PPCM.

Lack of JunD promotes pressure overload-induced apoptosis, hypertrophic growth, and angiogenesis in the heart.

BACKGROUND: The Jun family of activator protein 1 (AP-1) transcription factors (c-Jun, JunB, and JunD) is involved in fundamental biological processes such as proliferation, apoptosis, tumor angiogenesis, and hypertrophy. The role of individual AP-1 transcription factors in the stressed heart is not clear. In the present study we analyzed the role of JunD in survival, hypertrophy, and angiogenesis in the pressure-overloaded mouse heart after thoracic aortic constriction. METHODS AND RESULTS: Mice lacking JunD (knockout [KO]) showed increased mortality and enhanced cardiomyocyte apoptosis and fibrosis associated with increased levels of hypoxia-induced factor-1alpha, vascular endothelial growth factor (VEGF), p53, and Bax protein and reduced levels of Bcl-2 protein after 7 days of severe pressure overload compared with wild-type (WT) siblings. Cardiomyocyte hypertrophy in surviving KO mice was enhanced compared with that in WT mice. Chronic moderate pressure overload for 12 weeks caused enhanced left ventricular hypertrophy in KO mice, and survival and interstitial fibrosis were comparable with WT mice. Cardiac function, 12 weeks after operation, was comparable among shams and pressure-overloaded mice of both genotypes. In addition, KO mice exposed to chronic pressure overload showed higher cardiac capillary density associated with increased protein levels of VEGF. CONCLUSIONS: Thus, JunD limits cardiomyocyte hypertrophy and protects the pressure-overloaded heart from cardiac apoptosis. These beneficial effects of JunD, however, are associated with antiangiogenic properties.

Increased collagen deposition and diastolic dysfunction but preserved myocardial hypertrophy after pressure overload in mice lacking PKCepsilon.

Overexpression and activation of protein kinase C-epsilon (PKCepsilon) results in myocardial hypertrophy. However, these observations do not establish that PKCepsilon is required for the development of myocardial hypertrophy. Thus, we subjected PKCepsilon-knockout (KO) mice to a hypertrophic stimulus by transverse aortic constriction (TAC). KO mice show normal cardiac morphology and function. TAC caused similar cardiac hypertrophy in KO and wild-type (WT) mice. However, KO mice developed more interstitial fibrosis and showed enhanced expression of collagen Ialpha1 and collagen III after TAC associated with diastolic dysfunction, as assessed by tissue Doppler echocardiography (Ea/Aa after TAC: WT 2.1+/-0.3 versus KO 1.0+/-0.2; P<0.05). To explore underlying mechanisms, we analyzed the left ventricular (LV) expression pattern of additional PKC isoforms (ie, PKCalpha, PKCbeta, and PKCdelta). After TAC, expression and activation of PKCdelta protein was increased in KO LVs. Moreover, KO LVs displayed enhanced activation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK), whereas p42/p44-MAPK activation was attenuated. Under stretch, cultured KO fibroblasts showed a 2-fold increased collagen Ialpha1 (col Ialpha1) expression, which was prevented by PKCdelta inhibitor rottlerin or by p38 MAPK inhibitor SB 203580. In conclusion, PKCepsilon is not required for the development of a pressure overload-induced myocardial hypertrophy. Lack of PKCepsilon results in upregulation of PKCdelta and promotes activation of p38 MAPK and JNK, which appears to compensate for cardiac hypertrophy, but in turn, is associated with increased collagen deposition and impaired diastolic function.