VEGF-A plasma levels are associated with microvascular obstruction in patients with ST-segment elevation myocardial infarction.

BACKGROUND: Microvascular obstruction (MVO) is associated with poor outcome after ST-segment elevation myocardial infarction (STEMI). Vascular endothelial growth factor-A (VEGF-A) is a vascular permeability inducer playing a key role in MVO pathogenesis. We aimed to assess whether VEGF-A levels are associated with MVO, when evaluated by magnetic resonance imaging (MRI) in STEMI patients. METHODS: The multicenter prospective PREGICA study included a CMR substudy with all consecutive patients with a first STEMI who had undergone cardiac MRI at baseline and at 6-month follow-up. Patients with initial TIMI flow >1 were excluded. VEGF-A levels were measured in blood samples drawn at inclusion. RESULTS: Between 2010 and 2017, 147 patients (mean age 57 ±â€¯10 years; 84% males) were included. MVO was present in 65 (44%) patients. After multivariate analysis, higher troponin peak (OR 1.005; 95% CI 1.001-1.008; p = 0.007) and VEGF-A levels (OR 1.003; 95% CI 1.001-1.005; p = 0.015) were independently associated with MVO. When considering only patients with successful percutaneous coronary intervention (final TIMI flow 3, n = 130), higher troponin peak (p = 0.004) and VEGF-A levels (p = 0.03) remained independently predictive of MVO. Moreover, MVO was associated with adverse left ventricular (LV) remodeling and VEGF-A levels were significantly and inversely correlated with LV ejection fraction (EF) at 6-month follow-up. CONCLUSION: Our results show that VEGF-A levels were independently associated with MVO during STEMI and correlated with mid-term LVEF alteration. VEGF-A could therefore be considered as a biomarker of MVO in STEMI patients and be used to stratify patient prognosis.

Sequential alterations in Akt, GSK3ß, and calcineurin signalling in the mouse left ventricle after thoracic aortic constriction.

Left ventricular hypertrophy (LVH) is an adaptive response to chronic biomechanical stress that generally progresses to maladaptive hypertrophy and heart failure (HF). We studied the activation of protein kinase B (Akt/PKB), glycogen synthase kinase 3 beta (GSK3ß), and calcineurin (Cn) at 3, 7, 15, 30, and 60 days following transverse aortic constriction (TAC) in 4-week-old mice. Following TAC, GSK3ß inactivation at day 3 was associated with Akt activation, whereas at days 15 and 30, it appeared to be controlled by other kinases. Moderate nonsignificant Cn activation occurred at the early stages, and peak activation at day 30, concomitant with GSK3ß inactivation and overt LVH and HF. At the latest stage (day 60), despite further progression of LVH and HF, Cn activation appeared attenuated. Early stages of LVH were associated with Ca2+-handling protein upregulation, whereas major Cn activation, associated with GSK3ß inactivation, appeared to engage maladaptive hypertrophy and progression to HF associated with Ca2+-handling protein downregulation.

Percutaneous intracoronary delivery of SERCA gene increases myocardial function: a tissue Doppler imaging echocardiographic study.

The aim of this study was to examine the efficiency of adenovirus-mediated overexpression of sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA1a) gene in a realistic model based on percutaneous intracoronary delivery and on noninvasive functional monitoring. Catheter-based selective coronary delivery of saline or adenoviruses (Ad.CMV.SERCA1a or Ad.CMV.lacZ, 10(10) plaque-forming units) was performed in the circumflex artery of rabbits. Effects were assessed and compared by using serial Doppler echocardiography, hemodynamics, and measurements of SERCA protein and Ca(2+) uptake activity. On day 3, a 21% increase in SERCA proteins and a 37% increase in the maximal rate of Ca(2+) uptake were observed in the transfected left ventricular (LV) walls of Ad.CMV.SERCA1a rabbits. Baseline hemodynamics and conventional echographic measurements of global LV function were poorly affected. In contrast, tissue Doppler imaging (TDI) was able to assess a strong increase in the baseline function of transfected LV walls, as assessed with maximal wall velocities (+32% and +43%, respectively) and strain rates (+18% and +30%, respectively). TDI parameters were closely related to the maximal rate of Ca(2+) uptake (r(2) = 0.68 for the systolic strain rate). Serial TDI analysis during follow-up showed that the effects lasted for 7 days and were no longer detectable 15 days after adenoviruses injection. In conclusion, LV function can be increased by adenovirus-mediated overexpression of SERCA in a clinically relevant model, and TDI provides an accurate and noninvasive tool for monitoring effects on global as well as regional myocardial function.

Left ventricular SERCA2a gene down-regulation does not parallel ANP gene up-regulation during post-MI remodelling in rats.

BACKGROUND: In most animal models of chronic hemodynamic overload of the left ventricle (LV) as well as in human end stage heart failure, the sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA2a) mRNA levels are decreased in parallel with increased atrial natriuretic peptide (ANP) mRNA levels. The situation in the remote myocardium following myocardial infarction (MI) is unclear. AIMS: (1) To examine SERCA2a mRNA levels in the non-infarcted LV myocardium of rats at the chronic stage of experimental MI and (2) To examine whether a negative linear correlation exists between SERCA2a and ANP mRNA levels in this model. METHODS: Anesthetized adult male Wistar rats underwent left coronary artery ligation or sham operation. Three months later, the rats were divided into three groups: sham-operated rats (sham, n=21), HF-free rats with MI (non-failing (NF)-MI, n=29) and rats with both MI and HF (congestive heart failure (CHF)-MI, n=14). LV remodelling and function were assessed by echocardiography and hemodynamic measurements. SERCA2a and ANP mRNA levels were determined by Northern and dot blot analysis with specific cDNA probes. RESULTS: LV SERCA2a mRNA levels varied markedly in sham-operated rats (0.9-1.8). Mean ANP mRNA level increased markedly and mean SERCA2a mRNA level decreased moderately in the remote myocardium. In some NF-MI rats, SERCA2a mRNA levels were higher than those in some sham controls. Whereas ANP mRNA levels correlated well with MI severity (r2=0.79, p<0.001), this was not the case for SERCA2a mRNA levels (r2=0.42, p<0.01). We found no negative correlation between ANP and SERCA2a mRNA levels. CONCLUSION: SERCA2a gene down-regulation in the non-infarcted myocardium of rats with MI does not correlate with ANP gene up-regulation, suggesting that the two genes are not antithetically regulated.

The plasminogen-MMP system is more activated in the scar than in viable myocardium 3 months post-MI in the rat.

Left ventricular (LV) remodeling following myocardial infarction (MI) is a complex process involving extracellular matrix degradation and fibrosis. While early remodeling is beneficial, chronic remodeling leads to decompensated heart failure (HF). We assessed the hypothesis that activation of the plasminogen-MMP system is involved in the remodeling of the infarct scar and compared it to the remaining viable myocardium. MI was induced by coronary artery ligature in 42 male Wistar rats. Three months following surgery, animals were divided into compensated (n=26) or decompensated (n=16) groups and compared to sham-operated rats (n=17). Scar and remaining viable LV myocardium (LVM) were separately analyzed for MMP-2, -7, -9, urokinase type and tissue type plasminogen activator (uPA and tPA) mRNA levels by RT-PCR. Their protein or activity levels, plus those of plasminogen/plasmin, tissue inhibitor of metalloproteinase-1, -2, -4 (TIMP-1, -2, -4) and plasminogen activator inhibitor-1 (PAI-1) were analyzed in tissue conditioned media by Western blot, ELISA and/or zymography. MMP and plasmin proteolytic activities were increased in the scar as compared to paired LVM thus indicating that activation of plasminogen and pro-MMPs is a key event in scar tissue remodeling. MMP and plasminogen activators (uPA, tPA) mRNAs were increased accordingly. Furthermore, inhibitors of the proteolytic enzymes, TIMP-1 and PAI-1 were increased in the scars from failing hearts and LVM thus suggesting a dynamic interplay between proteolysis and its inhibitors. This study shows a high degree of activation of the MMP-plasminogen system and the balance with their inhibitors in the infarcted myocardium, and suggests that this activation participates more to the remodeling of the scar tissue than to the remaining myocardium.

Constitutive cardiac overexpression of sarcoplasmic/endoplasmic reticulum Ca2+-ATPase delays myocardial failure after myocardial infarction in rats at a cost of increased acute arrhythmias.

BACKGROUND: Heart failure often complicates myocardial infarction (MI), and sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA2a) is underexpressed in the failing myocardium. We examined the effect of preexisting cardiac SERCA2a protein overexpression on rat survival and left ventricular (LV) remodeling after MI. METHODS AND RESULTS: Baseline myocardial SERCA2a expression was 37% higher in transgenic (TG) rats than in their wild-type (WT) controls, consistent with enhanced myocardial function. The mortality rate of TG rats during the 24 hours after surgical MI was higher than that of WT rats (71% versus 35%, P<0.001), associated with a higher frequency of ventricular arrhythmias, and was normalized by lidocaine treatment. The increased acute-phase mortality in TG rats was not accompanied by increased 6-month mortality. Function of the noninfarcted myocardium, as assessed by tissue Doppler imaging, was higher in TG rats than in WT rats for up to 1 month after MI, a beneficial effect no longer observed at 3 months. LV remodeling and global function were similar in TG and WT rats. No difference in papillary muscle function was found at 6 months. CONCLUSIONS: Constitutive cardiac SERCA2a overexpression has a transient beneficial effect on remote myocardium function in rat MI, with no improvement in LV global function or prevention of LV remodeling and failure. This benefit is associated with a higher risk of acute mortality, which is prevented by lidocaine treatment.

Pulmonary endothelium as a site of synthesis and storage of interleukin-6 in experimental congestive heart failure.

BACKGROUND: Pulmonary endothelium is an early upstream hemodynamic target of left ventricular dysfunction. Interleukin 6 (IL-6) is a pro-inflammatory cytokine reported to increase in congestive heart failure (CHF) patients. AIMS: We sought to determine the origin of IL-6, IL-6 receptor (IL-6R) and gp130 in experimental CHF. METHODS: We used rats with coronary artery ligation as an experimental model of either compensated or decompensated heart failure. Lung and aorta samples were analysed by RT-PCR, ELISA and immunohistochemistry for IL-6 and its receptors. RESULTS: IL-6 mRNA expression increased in the lung of rats with decompensated heart failure and was positively correlated with infarct severity whereas IL-6R mRNA decreased in the lung of myocardial infarction rats and gp130 mRNA remained unchanged. In contrast, there were no changes in IL-6 mRNA expression in the aorta and left ventricular myocardium. IL-6 peptide content as determined by ELISA and Western Blot in lung tissue was 2-fold higher in decompensated heart failure as compared to control rats. These data were confirmed by immunohistochemistry showing a preferential endothelial localization of IL-6 in the CHF lung. IL-6 peptide was also present in the pleural effusion of decompensated heart failure and was positively correlated with IL-6 mRNA expression in the lungs of decompensated HF rats. Pulmonary IL-6 overexpression was associated with nuclear translocation of NF-kappaB and cytosolic degradation of IkappaB. CONCLUSION: Dysfunctional pulmonary endothelium is a source of synthesis and storage of IL-6 in an experimental model of CHF.

Doppler echocardiographic estimation of left ventricular end-diastolic pressure after MI in rats.

The spectral Doppler mitral flow pattern, alone or combined with tissue Doppler mitral annulus velocity, can be used to predict left ventricular (LV) filling pressure in humans, whereas invasive hemodynamic measurements are still required in the rat. This study was undertaken to assess whether LV end-diastolic pressure (LVEDP) can be estimated using Doppler echocardiography in the rat after myocardial infarction (MI). Thirty-seven rats (23 rats with MI after left coronary artery ligation and 14 sham-operated rats) were evaluated 3 mo after surgery with echo-Doppler and invasive hemodynamic measurements. Pulse wave spectral Doppler at the mitral valve tip was used to measure the E wave, the E wave deceleration time (DT), and the A wave; spectral Doppler tissue imaging was used to measure the early diastolic lateral mitral annulus velocity (E(a)). We found weak correlations between LVEDP and the peak velocity of the early mitral inflow (E), E/peak velocity of the late mitral inflow, and DT, and strong correlations with E(a) and especially with E/E(a) [R(2) = 0.89, LVEDP (in mmHg) = 0.987E/E(a) - 4.229]. Longitudinal followup of a subgroup of rats with MI revealed a marked rise of E/E(a) between days 7 and 21 in rats with heart failure only. We conclude that Doppler echocardiography can be used for serial assessment of LV diastolic function in rats with MI.