Jørgen Gravning

Mechanisms of novel cardioprotective functions of CCN2/CTGF in myocardial ischemia-reperfusion injury

CCN2/connective tissue growth factor (CTGF), a CCN family matricellular protein repressed in healthy hearts after birth, is induced in heart failure of various etiologies. Multiple cellular and biological functions have been assigned to CCN2/CTGF depending on cellular context. However, the functions and mechanisms of action of CCN2/CTGF in the heart as well as its roles in cardiac physiology and pathophysiology remain unknown. Transgenic mice with cardiac-restricted overexpression of CTGF (Tg-CTGF) were generated and compared with nontransgenic littermate control (NLC) mice. Tg-CTGF mice displayed slightly lower cardiac mass and inconspicuous increase of myocardial collagen compared with NLC mice but no evidence of contractile dysfunction. Analysis of the myocardial transcriptome by DNA microarray revealed activation of several distinct gene programs in Tg-CTGF hearts involved in cardioprotection and growth inhibition. Indeed, Tg-CTGF mice subjected to ischemia-reperfusion injury by in situ transient occlusion of the left anterior descending coronary artery in vivo displayed reduced vulnerability with markedly diminished infarct size. These findings were recapitulated in isolated hearts perfused with recombinant human (h)CTGF before the ischemia-reperfusion procedure. Consistently, Tg-CTGF hearts, as well as isolated adult cardiac myocytes exposed to recombinant hCTGF, displayed enhanced phosphorylation and activity of the Akt/p70S6 kinase/GSK-3β salvage kinase pathway and induction of several genes with reported cardioprotective functions. Inhibition of Akt activities also prevented the cardioprotective phenotype of hearts from Tg-CTGF mice. This report provides novel evidence that CTGF confers cardioprotection by salvage phosphokinase signaling leading to inhibition of GSK-3β activities, activation of phospho-SMAD2, and reprogramming of gene expression.

Soluble Glycoprotein 130 Predicts Fatal Outcomes in Chronic Heart Failure Analysis From the Controlled Rosuvastatin Multinational Trial in Heart Failure (CORONA)

Background— Glycoprotein 130 (gp130) is the common signal-transducing receptor subunit of the interleukin-6 (IL-6) family, which may be involved in the progression of heart failure (HF). We hypothesized that soluble gp130 would provide prognostic information beyond that of IL-6 in a population with HF from the Controlled Rosuvastatin Multinational Trial in Heart Failure (CORONA). Methods and Results— The associations of soluble gp130 and IL-6 with morbidity, mortality, and mode of death were assessed by immunoassays in a subset of 1452 patients enrolled in the CORONA trial, which included patients with HF, aged ≥60 years, in New York Heart Association classes II to IV, who had ischemic heart disease and a reduced left ventricular ejection fraction. In multivariable analyses, including C-reactive protein, IL-6, troponin T, and N-terminal pro-B-type natriuretic peptide, elevated soluble gp130 (fifth quintile versus all lower quintiles) was associated with all-cause mortality (hazard ratio, 1.47 [1.11–1.93]; P =0.006), cardiovascular mortality (hazard ratio, 1.38 [1.01–1.87]; P =0.042), and death from worsening HF (hazard ratio, 1.85 [1.09–3.14]; P =0.002), but not with the primary end point (composite of death from cardiovascular causes, nonfatal myocardial infarction, and nonfatal stroke; hazard ratio, 1.12 [0.84–1.50]; P =0.44). Plasma IL-6 was not associated with outcomes in multivariable analyses. Conclusions— Marked elevations in soluble gp130 are associated with total and cardiovascular mortality, as well as deaths from worsening HF, in elderly patients with HF of ischemic cause Clinical Trial Registration— URL: . Unique identifier: [NCT00206310][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00206310&atom=%2Fcirchf%2F6%2F1%2F91.atomBackground— Glycoprotein 130 (gp130) is the common signal-transducing receptor subunit of the interleukin-6 (IL-6) family, which may be involved in the progression of heart failure (HF). We hypothesized that soluble gp130 would provide prognostic information beyond that of IL-6 in a population with HF from the Controlled Rosuvastatin Multinational Trial in Heart Failure (CORONA). Methods and Results— The associations of soluble gp130 and IL-6 with morbidity, mortality, and mode of death were assessed by immunoassays in a subset of 1452 patients enrolled in the CORONA trial, which included patients with HF, aged ≥60 years, in New York Heart Association classes II to IV, who had ischemic heart disease and a reduced left ventricular ejection fraction. In multivariable analyses, including C-reactive protein, IL-6, troponin T, and N-terminal pro-B-type natriuretic peptide, elevated soluble gp130 (fifth quintile versus all lower quintiles) was associated with all-cause mortality (hazard ratio, 1.47 [1.11–1.93]; P=0.006), cardiovascular mortality (hazard ratio, 1.38 [1.01–1.87]; P=0.042), and death from worsening HF (hazard ratio, 1.85 [1.09–3.14]; P=0.002), but not with the primary end point (composite of death from cardiovascular causes, nonfatal myocardial infarction, and nonfatal stroke; hazard ratio, 1.12 [0.84–1.50]; P=0.44). Plasma IL-6 was not associated with outcomes in multivariable analyses. Conclusions— Marked elevations in soluble gp130 are associated with total and cardiovascular mortality, as well as deaths from worsening HF, in elderly patients with HF of ischemic cause Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00206310.

Myocardial Connective Tissue Growth Factor (CCN2/CTGF) Attenuates Left Ventricular Remodeling after Myocardial Infarction

Aims Myocardial CCN2/CTGF is induced in heart failure of various etiologies. However, its role in the pathophysiology of left ventricular (LV) remodeling after myocardial infarction (MI) remains unresolved. The current study explores the role of CTGF in infarct healing and LV remodeling in an animal model and in patients admitted for acute ST-elevation MI. Methods and Results Transgenic mice with cardiac-restricted overexpression of CTGF (Tg-CTGF) and non-transgenic littermate controls (NLC) were subjected to permanent ligation of the left anterior descending coronary artery. Despite similar infarct size (area of infarction relative to area at risk) 24 hours after ligation of the coronary artery in Tg-CTGF and NLC mice, Tg-CTGF mice disclosed smaller area of scar tissue, smaller increase of cardiac hypertrophy, and less LV dilatation and deterioration of LV function 4 weeks after MI. Tg-CTGF mice also revealed substantially reduced mortality after MI. Remote/peri-infarct tissue of Tg-CTGF mice contained reduced numbers of leucocytes, macrophages, and cells undergoing apoptosis as compared with NLC mice. In a cohort of patients with acute ST-elevation MI (n = 42) admitted to hospital for percutaneous coronary intervention (PCI) serum-CTGF levels (s-CTGF) were monitored and related to infarct size and LV function assessed by cardiac MRI. Increase in s-CTGF levels after MI was associated with reduced infarct size and improved LV ejection fraction one year after MI, as well as attenuated levels of CRP and GDF-15. Conclusion Increased myocardial CTGF activities after MI are associated with attenuation of LV remodeling and improved LV function mediated by attenuation of inflammatory responses and inhibition of apoptosis.

Plasma CCN2/connective tissue growth factor is associated with right ventricular dysfunction in patients with neuroendocrine tumors

BackgroundCarcinoid heart disease, a known complication of neuroendocrine tumors, is characterized by right heart fibrotic lesions. Carcinoid heart disease has traditionally been defined by the degree of valvular involvement. Right ventricular (RV) dysfunction due to mural involvement may also be a manifestation. Connective tissue growth factor (CCN2) is elevated in many fibrotic disorders. Its role in carcinoid heart disease is unknown. We sought to investigate the relationship between plasma CCN2 and valvular and mural involvement in carcinoid heart disease.MethodsEchocardiography was performed in 69 patients with neuroendocrine tumors. RV function was assessed using tissue Doppler analysis of myocardial systolic strain. Plasma CCN2 was analyzed using an enzyme-linked immunosorbent assay. Mann-Whitney U, Kruskal-Wallis, Chi-squared and Fishers exact tests were used to compare groups where appropriate. Linear regression was used to evaluate correlation.ResultsMean strain was -21% ± 5. Thirty-three patients had reduced RV function (strain > -20%, mean -16% ± 3). Of these, 8 had no or minimal tricuspid and/or pulmonary regurgitation (TR/PR). Thirty-six patients had normal or mildly reduced RV function (strain ≤ -20%, mean -25% ± 3). There was a significant inverse correlation between RV function and plasma CCN2 levels (r = 0.47, p < 0.001). Patients with reduced RV function had higher plasma CCN2 levels than those with normal or mildly reduced RV function (p < 0.001). Plasma CCN2 ≥ 77 μg/L was an independent predictor of reduced RV function (odds ratio 15.36 [95% CI 4.15;56.86]) and had 88% sensitivity and 69% specificity for its detection (p < 0.001). Plasma CCN2 was elevated in patients with mild or greater TR/PR compared to those with no or minimal TR/PR (p = 0.008), with the highest levels seen in moderate to severe TR/PR (p = 0.03).ConclusionsElevated plasma CCN2 levels are associated with RV dysfunction and valvular regurgitation in NET patients. CCN2 may play a role in neuroendocrine tumor-related cardiac fibrosis and may serve as a marker of its earliest stages.

CCN2/CTGF attenuates myocardial hypertrophy and cardiac dysfunction upon chronic pressure-overload

BACKGROUND Myocardial CCN2/CTGF (connective tissue growth factor) is strongly induced in heart failure (HF) and acts as a cardioprotective factor in ischemia/reperfusion injury. However, its functional role in myocardial hypertrophy remains unresolved. METHODS AND RESULTS Transgenic mice with cardiac-restricted overexpression of CTGF (Tg-CTGF) and non-transgenic littermate control (NLC) mice were subjected to chronic pressure-overload by abdominal aortic banding. After 4weeks of persistent pressure-overload, a time point at which compensatory hypertrophy of the left ventricle (LV) prevails, Tg-CTGF mice displayed diminished increase of LV mass compared with NLC. At study end-point after 12 weeks of sustained aortic constriction, the mice displayed LV dilatation and reduced cardiac function. Repeated transthoracic echocardiography during the 12 weeks of chronic pressure-overload, revealed attenuation of LV dilatation and virtually sustained systolic function in Tg-CTGF mice compared with NLC mice. Also, increase of LV mass was blunted in Tg-CTGF versus NLC mice at study end-point. Consistently, increases of myocardial ANP, BNP and skeletal α-actin mRNA levels were blunted in Tg-CTGF mice subjected to chronic pressure-overload. Furthermore, cardiac myocytes from Tg-CTGF mice displayed increased phospho-NFATc2 levels and attenuated hypertrophic response upon stimulation with α1-adrenoceptor agonist, indicating that CTGF attenuates hypertrophic signaling in cardiac myocytes. Increase of myocardial collagen contents in mice subjected to aortic banding was similar in Tg-CTGF and NLC mice, indicating that CTGF have minimal impact on myocardial collagen deposition. CONCLUSION This study provides novel evidence that CTGF attenuates cardiac hypertrophy upon chronic pressure-overload due to inhibition of signaling mechanisms that promote pathologic myocardial hypertrophy.

Prognostic Effect of High-Sensitive Troponin T Assessment in Elderly Patients With Chronic Heart Failure Results From the CORONA Trial

Background— The incremental prognostic value of high-sensitive troponin T (hs-cTnT) in heart failure (HF) beyond that of high-sensitivity C-reactive protein and amino-terminal probrain natriuretic peptide is debated. We examined the prognostic value of hs-cTnT in a subgroup of patients from the Controlled Rosuvastatin Multinational Trial in HF (CORONA) study. Methods and Results— Hs-cTnT as a risk factor for the primary end point (cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke; n=356), as well as all-cause mortality (n=366), cardiovascular mortality (n=299), and the composite of cardiovascular mortality and hospitalization from worsening of HF (n=465), was investigated in 1245 patients (≥60 years; New York Heart Association [NYHA] class II–IV, ischemic systolic HF) randomly assigned to 10 mg rosuvastatin or placebo. In multivariable analyses, adjusting for left ventricular ejection fraction, NYHA class, age, body mass index, diabetes mellitus, sex, intermittent claudication, heart rate, estimated glomerular filtration rate, apolipoprotein B/apolipoprotein A-1 ratio, amino-terminal probrain natriuretic peptide, high-sensitivity C-reactive protein, and hs-cTnT (both dichotomized according to the 99th percentile and as a continuous variable) was associated with all end points (primary end point: hazard ratio, 1.87 and 1.51, respectively, per SD change; P<0.001; all other end points: hazard ratio, 1.39–1.70). However, improved discrimination as assessed by C-statistics was only seen for the primary end point and all-cause mortality. Conclusions— Elevated hs-cTnT levels provide strong and independent prognostic information in older patients with chronic ischemic HF. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00206310.

Sensitive troponin assays and N-terminal pro–B-type natriuretic peptide in acute coronary syndrome: Prediction of significant coronary lesions and long-term prognosis

BACKGROUND Sensitive troponin assays have substantially improved early diagnosis of myocardial infarction. However, the role of sensitive cardiac troponin (cTn) assays in prediction of significant coronary lesions and long-term prognosis in non-ST-elevation acute coronary syndrome (NSTE-ACS) remains unresolved. METHODS This prospective study includes 458 consecutive patients with NSTE-ACS admitted for coronary angiography. Serum levels of 4 commercial available sensitive troponin assays were analyzed (Roche high-sensitive cTnT [hs-cTnT; Roche Diagnostics, Basel, Switzerland], Siemens cTnI Ultra [Siemens, Munich, Germany], Abbott-Architect cTnI [Abbott, Abbott Park, IL], Access Accu-cTnI [Beckman Coulter, Nyon, Switzerland]), as well as a standard assay (Roche cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), before coronary angiography. RESULTS The relationship between the analyzed biomarkers and significant coronary lesions on coronary angiography, as quantified by area under the receiver operating characteristic curve, was significantly higher with Roche hs-cTnT, Siemens cTnI Ultra, and Access Accu-cTnI as compared with standard troponin T assay (P < .001 for all comparisons). This difference was mainly caused by increased sensitivity below the 99th percentile. Also, NT-proBNP was associated with the presence of significant coronary lesions. Cardiac troponin values were correlated with cardiac death (primary end point) during 1373 (1257-1478) days of follow-up. In both univariate and multivariate Cox regression analyses, NT-proBNP was superior to both hs-cTnT and cTnI in prediction of cardiovascular mortality. Troponin values with all assays were correlated with the need for repeated revascularization (secondary end point) during follow-up. CONCLUSIONS Sensitive cTn assays are superior to standard cTnT assay in prediction of significant coronary lesions in patients with NSTE-ACS. However, this improvement is primary caused by increased sensitivity below the 99th percentile. N-terminal pro-B-type natriuretic peptide is superior to cTns in prediction of long-term mortality.

Gene therapy with hypoxia-inducible factor 1 alpha in skeletal muscle is cardioprotective in vivo

AIMS Gene therapy of a peripheral organ to protect the heart is clinically attractive. The transcription factor hypoxia-inducible factor 1 alpha (HIF-1α) transactivates cardioprotective genes. We investigated if remote delivery of DNA encoding for HIF-1α is protective against myocardial ischemia-reperfusion injury in vivo. MAIN METHODS DNA encoding for human HIF-1α was delivered to quadriceps muscles of mice. One week later myocardial infarction was induced and four weeks later its size was measured. Echocardiography and in vivo pressure-volume analysis was performed. Coronary vascularization was evaluated through plastic casting. HL-1 cells, transfected with either HIF-1α or HMOX-1 or administered bilirubin or the carbon monoxide (CO) donor CORM-2, were subjected to lipopolysacharide (LPS)-induced cell death to compare the efficacy of treatments. KEY FINDINGS After four weeks of reperfusion post infarction, animals pretreated with HIF-1α showed reduced infarct size and left ventricular remodeling (p<0.05, respectively). Fractional shortening was preserved in mice pretreated with HIF-1α (p<0.05). Invasive hemodynamic parameters indicated preserved left ventricular function after HIF-1α (p<0.05), which also induced coronary vascularization (p<0.05). HIF-1α downstream target heme oxygenase 1 (HMOX-1) was upregulated in skeletal muscle, while serum bilirubin was increased. Transfection of HL-1 cells with HIF-1α or HMOX-1 and administration of bilirubin or CORM-2 comparably salvaged cells from lipopolysacharide (LPS)-induced cell death (all p<0.05). SIGNIFICANCE HIF-1α gene delivery to skeletal muscle preceding myocardial ischemia reduced infarct size and postischemic remodeling accompanied by an improved cardiac function and vascularization. Similar to HIF-1α, HMOX-1, bilirubin and CO were protective against LPS-induced injury. This observation may have clinical potential.

Prognostic Effect of High-Sensitive Troponin T Assessment in Elderly Patients With Chronic Heart FailureClinical Perspective

Background— The incremental prognostic value of high-sensitive troponin T (hs-cTnT) in heart failure (HF) beyond that of high-sensitivity C-reactive protein and amino-terminal probrain natriuretic peptide is debated. We examined the prognostic value of hs-cTnT in a subgroup of patients from the Controlled Rosuvastatin Multinational Trial in HF (CORONA) study. Methods and Results— Hs-cTnT as a risk factor for the primary end point (cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke; n=356), as well as all-cause mortality (n=366), cardiovascular mortality (n=299), and the composite of cardiovascular mortality and hospitalization from worsening of HF (n=465), was investigated in 1245 patients (≥60 years; New York Heart Association [NYHA] class II–IV, ischemic systolic HF) randomly assigned to 10 mg rosuvastatin or placebo. In multivariable analyses, adjusting for left ventricular ejection fraction, NYHA class, age, body mass index, diabetes mellitus, sex, intermittent claudication, heart rate, estimated glomerular filtration rate, apolipoprotein B/apolipoprotein A-1 ratio, amino-terminal probrain natriuretic peptide, high-sensitivity C-reactive protein, and hs-cTnT (both dichotomized according to the 99th percentile and as a continuous variable) was associated with all end points (primary end point: hazard ratio, 1.87 and 1.51, respectively, per SD change; P<0.001; all other end points: hazard ratio, 1.39–1.70). However, improved discrimination as assessed by C-statistics was only seen for the primary end point and all-cause mortality. Conclusions— Elevated hs-cTnT levels provide strong and independent prognostic information in older patients with chronic ischemic HF. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00206310.

Cardiomyocyte-restricted inhibition of G protein-coupled receptor kinase-3 attenuates cardiac dysfunction after chronic pressure overload

Transgenic mice with cardiac-specific expression of a peptide inhibitor of G protein-coupled receptor kinase (GRK)3 [transgenic COOH-terminal GRK3 (GRK3ct) mice] display myocardial hypercontractility without hypertrophy and enhanced α(1)-adrenergic receptor signaling. A role for GRK3 in the pathogenesis of heart failure (HF) has not been investigated, but inhibition of its isozyme, GRK2, has been beneficial in several HF models. Here, we tested whether inhibition of GRK3 modulated evolving cardiac hypertrophy and dysfunction after pressure overload. Weight-matched male GRK3ct transgenic and nontransgenic littermate control (NLC) mice subjected to chronic pressure overload by abdominal aortic banding (AB) were compared with sham-operated (SH) mice. At 6 wk after AB, a significant increase of cardiac mass consistent with induction of hypertrophy was found, but no differences between GRK3ct-AB and NLC-AB mice were discerned. Simultaneous left ventricular (LV) pressure-volume analysis of electrically paced, ex vivo perfused working hearts revealed substantially reduced systolic and diastolic function in NLC-AB mice (n = 7), which was completely preserved in GRK3ct-AB mice (n = 7). An additional cohort was subjected to in vivo cardiac catheterization and LV pressure-volume analysis at 12 wk after AB. NLC-AB mice (n = 11) displayed elevated end-diastolic pressure (8.5 ± 3.1 vs. 2.9 ± 1.2 mmHg, P < 0.05), reduced cardiac output (3,448 ± 323 vs. 4,488 ± 342 μl/min, P < 0.05), and reduced dP/dt(max) and dP/dt(min) (both P < 0.05) compared with GRK3ct-AB mice (n = 16), corroborating the preserved cardiac structure and function observed in GRK3ct-AB hearts assessed ex vivo. Increased cardiac mass and myocardial mRNA expression of β-myosin heavy chain confirmed the similar induction of cardiac hypertrophy in both AB groups, but only NLC-AB hearts displayed significantly elevated mRNA levels of brain natriuretic peptide and myocardial collagen contents as well as reduced β(1)-adrenergic receptor responsiveness to isoproterenol, indicating increased LV wall stress and the transition to HF. Inhibition of cardiac GRK3 in mice does not alter the hypertrophic response but attenuates cardiac dysfunction and HF after chronic pressure overload.