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Contains fulltext : 286832.pdf (Publisher’s version ) (Open Access) BACKGROUND: Direct evaluation of vascular inflammation in patients with COVID-19 would facilitate more efficient trials of new treatments and identify patients at risk of long-term complications who might respond to treatment. We aimed to develop a novel artificial intelligence (AI)-assisted image analysis platform that quantifies cytokine-driven vascular inflammation from routine CT angiograms, and sought to validate its prognostic value in COVID-19. METHODS: For this prospective outcomes validation study, we developed a radiotranscriptomic platform that uses RNA sequencing data from human internal mammary artery biopsies to develop novel radiomic signatures of vascular inflammation from CT angiography images. We then used this platform to train a radiotranscriptomic signature (C19-RS), derived from the perivascular space around the aorta and the internal mammary artery, to best describe cytokine-driven vascular inflammation. The prognostic value of C19-RS was validated externally in 435 patients (331 from study arm 3 and 104 from study arm 4) admitted to hospital with or without COVID-19, undergoing clinically indicated pulmonary CT angiography, in three UK National Health Service (NHS) trusts (Oxford, Leicester, and Bath). We evaluated the diagnostic and prognostic value of C19-RS for death in hospital due to COVID-19, did sensitivity analyses based on dexamethasone treatment, and investigated the correlation of C19-RS with systemic transcriptomic changes. FINDINGS: Patients with COVID-19 had higher C19-RS than those without (adjusted odds ratio [OR] 2·97 [95% CI 1·43-6·27], p=0·0038), and those infected with the B.1.1.7 (alpha) SARS-CoV-2 variant had higher C19-RS values than those infected with the wild-type SARS-CoV-2 variant (adjusted OR 1·89 [95% CI 1·17-3·20] per SD, p=0·012). C19-RS had prognostic value for in-hospital mortality in COVID-19 in two testing cohorts (high [≥6·99] vs low [

Aims Recent clinical trials indicate that sodium-glucose cotransporter 2 (SGLT2) inhibitors improve cardiovascular outcomes in heart failure patients, but the underlying mechanisms remain unknown. We explored the direct effects of canagliflozin, an SGLT2 inhibitor with mild SGLT1 inhibitory effects, on myocardial redox signalling in humans. Methods and results Study 1 included 364 patients undergoing cardiac surgery. Right atrial appendage biopsies were harvested to quantify superoxide (O2.−) sources and the expression of inflammation, fibrosis, and myocardial stretch genes. In Study 2, atrial tissue from 51 patients was used ex vivo to study the direct effects of canagliflozin on NADPH oxidase activity and nitric oxide synthase (NOS) uncoupling. Differentiated H9C2 and primary human cardiomyocytes (hCM) were used to further characterize the underlying mechanisms (Study 3). SGLT1 was abundantly expressed in human atrial tissue and hCM, contrary to SGLT2. Myocardial SGLT1 expression was positively associated with O2.− production and pro-fibrotic, pro-inflammatory, and wall stretch gene expression. Canagliflozin reduced NADPH oxidase activity via AMP kinase (AMPK)/Rac1signalling and improved NOS coupling via increased tetrahydrobiopterin bioavailability ex vivo and in vitro. These were attenuated by knocking down SGLT1 in hCM. Canagliflozin had striking ex vivo transcriptomic effects on myocardial redox signalling, suppressing apoptotic and inflammatory pathways in hCM. Conclusions We demonstrate for the first time that canagliflozin suppresses myocardial NADPH oxidase activity and improves NOS coupling via SGLT1/AMPK/Rac1 signalling, leading to global anti-inflammatory and anti-apoptotic effects in the human myocardium. These findings reveal a novel mechanism contributing to the beneficial cardiac effects of canagliflozin., Graphical Abstract Proposed mechanism of canagliflozin-induced improvement of myocardial redox state. Canagliflozin increases intracellular AMP/ATP ratio through inhibition of SGLT1, which can activate AMPK/NOS signalling and increase NO that suppresses pro-inflammatory signalling. AMPK activation also inhibits activation of Rac1 and membrane translocation of Rac1 and p47phox, which decrease NADPH oxidase activity and superoxide (O2.−) production, attenuates inflammatory and apoptotic pathways and increasing the bioavailability of tetrahydrobiopterin (BH4), a key factor for NOS coupling.

IntroductionBrain injury is common following open heart valve surgery. Carbon dioxide insufflation (CDI) has been proposed to reduce the incidence of brain injury by reducing the number of air microemboli entering the bloodstream in surgery. The CO2 Study will evaluate the efficacy and safety of CDI in patients undergoing planned left-sided open heart valve surgery.Methods and analysisThe CO2 Study is a multicentre, blinded, placebo-controlled, randomised controlled trial. Seven-hundred and four patients aged 50 years and over undergoing planned left-sided heart valve surgery will be recruited to the study, from at least eight UK National Health Service hospitals, and randomised in a 1:1 ratio to receive CDI or medical air insufflation (placebo) in addition to standard de-airing. Insufflation will be delivered at a flow rate of 5 L/min from before the initiation of cardiopulmonary bypass until 10 min after cardiopulmonary bypass weaning. Participants will be followed up until 3 months post-surgery. The primary outcome is acute ischaemic brain injury within 10 days post-surgery based on new brain lesions identified with diffusion-weighted MRI or clinical evidence of permanent brain injury according to the current definition of stroke.Ethics and disseminationThe study was approved by the East Midlands–Nottingham 2 Research Ethics Committee in June 2020 and the Medicines and Healthcare products Regulatory Agency in May 2020. All participants will provide written informed consent prior to undertaking any study assessments. Consent will be obtained by the principal investigator or a delegated member of the research team who has been trained in the study and undergone Good Clinical Practice training. Results will be disseminated through peer-reviewed publications and presentations at national and international meetings. Study participants will be informed of results through study notifications and patient organisations.Trial registration numberISRCTN30671536.

Aims Systemic inflammation and increased activity of atrial NOX2-containing NADPH oxidases have been associated with the new onset of atrial fibrillation (AF) after cardiac surgery. In addition to lowering LDL-cholesterol, statins exert rapid anti-inflammatory and antioxidant effects, the clinical significance of which remains controversial. Methods and results We first assessed the impact of cardiac surgery and cardiopulmonary bypass (CPB) on atrial nitroso-redox balance by measuring NO synthase (NOS) and GTP cyclohydrolase-1 (GCH-1) activity, biopterin content, and superoxide production in paired samples of the right atrial appendage obtained before (PRE) and after CPB and reperfusion (POST) in 116 patients. The effect of perioperative treatment with atorvastatin (80 mg once daily) on these parameters, blood biomarkers, and the post-operative atrial effective refractory period (AERP) was then evaluated in a randomized, double-blind, placebo-controlled study in 80 patients undergoing cardiac surgery on CPB. CPB and reperfusion led to a significant increase in atrial superoxide production (74% CI 71–76%, n = 46 paired samples, P, Graphical Abstract

Supplemental Digital Content is available in the text., Background: Why some but not all patients with severe aortic stenosis (SevAS) develop otherwise unexplained reduced systolic function is unclear. We investigate the hypothesis that reduced creatine kinase (CK) capacity and flux is associated with this transition. Methods: We recruited 102 participants to 5 groups: moderate aortic stenosis (ModAS) (n=13), SevAS, left ventricular (LV) ejection fraction ≥55% (SevAS-preserved ejection fraction, n=37), SevAS, LV ejection fraction 0.99). Accompanying the fall in CK flux, total CK and citrate synthase activities and the absolute activities of mitochondrial-type CK and CK-MM isoforms were also lower (P

Reperfusion-induced calcium overload profoundly affects the extent of myocardial injury following ischemia, impacting long-term morbidity and mortality. Reactive oxygen species play a crucial role in shaping the amplitude and spatiotemporal patterns of the intracellular calcium signal, but the mechanism governing this interplay remain unclear. Here we show that, in vivo, myocardial ischemia and reperfusion (I/R) potently induce formation of an intermolecular-disulfide within the type I regulatory subunits of protein kinase A (PKARIα), both in mice and in humans. This conformation does not increase intrinsic PKA catalytic activity, but rather promotes AKAP-mediated subcellular compartmentalization of PKARIα to the lysosome, where it inhibits calcium release from two-pore channels and prevents global calcium release from nearby ryanodine receptors. This regulatory mechanism is shown to be crucial for limiting I/R-induced cell death, as ‘redox dead’ Cys17Ser PKARIα knock-in mice, which are incapable of undergoing RIα disulfide formation, display substantially larger infarct sizes with concomitant reductions in left ventricular contractile recovery, both of which are prevented by inhibition of lysosomal calcium release at the time of reperfusion. These findings reveal a hitherto unknown role for PKARIα, in its disulfide-activated state, to regulate calcium homeostasis and, in this way, potently protect the myocardium from post-ischemic injury.

Supplemental Digital Content is available in the text., Background: Kinase oxidation is a critical signaling mechanism through which changes in the intracellular redox state alter cardiac function. In the myocardium, PKARIα (type-1 protein kinase A) can be reversibly oxidized, forming interprotein disulfide bonds in the holoenzyme complex. However, the effect of PKARIα disulfide formation on downstream signaling in the heart, particularly under states of oxidative stress such as ischemia and reperfusion (I/R), remains unexplored. Methods: Atrial tissue obtained from patients before and after cardiopulmonary bypass and reperfusion and left ventricular (LV) tissue from mice subjected to I/R or sham surgery were used to assess PKARIα disulfide formation by immunoblot. To determine the effect of disulfide formation on PKARIα catalytic activity and subcellular localization, live-cell fluorescence imaging and stimulated emission depletion super-resolution microscopy were performed in prkar1 knock-out mouse embryonic fibroblasts, neonatal myocytes, or adult LV myocytes isolated from “redox dead” (Cys17Ser) PKARIα knock-in mice and their wild-type littermates. Comparison of intracellular calcium dynamics between genotypes was assessed in fura2-loaded LV myocytes, whereas I/R-injury was assessed ex vivo. Results: In both humans and mice, myocardial PKARIα disulfide formation was found to be significantly increased (2-fold in humans, P=0.023; 2.4-fold in mice, P

Atrial fibrillation, the most common cardiac arrhythmia, is an important contributor to mortality and morbidity, and particularly to the risk of stroke in humans1. Atrial-tissue fibrosis is a central pathophysiological feature of atrial fibrillation that also hampers its treatment; the underlying molecular mechanisms are poorly understood and warrant investigation given the inadequacy of present therapies2. Here we show that calcitonin, a hormone product of the thyroid gland involved in bone metabolism3, is also produced by atrial cardiomyocytes in substantial quantities and acts as a paracrine signal that affects neighbouring collagen-producing fibroblasts to control their proliferation and secretion of extracellular matrix proteins. Global disruption of calcitonin receptor signalling in mice causes atrial fibrosis and increases susceptibility to atrial fibrillation. In mice in which liver kinase B1 is knocked down specifically in the atria, atrial-specific knockdown of calcitonin promotes atrial fibrosis and increases and prolongs spontaneous episodes of atrial fibrillation, whereas atrial-specific overexpression of calcitonin prevents both atrial fibrosis and fibrillation. Human patients with persistent atrial fibrillation show sixfold lower levels of myocardial calcitonin compared to control individuals with normal heart rhythm, with loss of calcitonin receptors in the fibroblast membrane. Although transcriptome analysis of human atrial fibroblasts reveals little change after exposure to calcitonin, proteomic analysis shows extensive alterations in extracellular matrix proteins and pathways related to fibrogenesis, infection and immune responses, and transcriptional regulation. Strategies to restore disrupted myocardial calcitonin signalling thus may offer therapeutic avenues for patients with atrial fibrillation.

Introduction: Kinase oxidation is a critical signaling mechanism through which changes in the intracellular redox state alter cardiac function. In the myocardium, the regulatory Iα subunit of Protein Kinase A (PKARIα) can be reversibly oxidised, forming interprotein disulfide bonds within the holoenzyme complex. However, the impact of disulfide formation on kinase function, and its influence on PKA signaling in the context of heart disease remains unknown. Methods & Results: Myocardial ischemia-reperfusion (I/R) was found to be a potent inducer of PKARIα disulfide formation in vivo , both in mice and in humans. Using imaging modalities with high spatial and temporal resolution, we found that this conformation did not increase intrinsic PKA catalytic activity, but rather facilitated enhanced AKAP-dependent compartmentation of PKARIα in the adult mouse left ventricular (LV) myocyte, with preferential localization to the lysosome under oxidized conditions (n=38-41 myocytes, N=3 animals, p Conclusions: Oxidised PKARIα acts as a potent inhibitor of intracellular calcium release in the heart through its redox-dependent interaction with the lysosome. In the setting of I/R, where PKA oxidation is induced, this regulatory mechanism is critical for protecting the heart from injury and offers a novel target for the design of cardioprotective therapeutics.

Based on current guidelines, 15% to 20% of patients undergoing mitral valve repair for regurgitation develop left ventricular dysfunction (ejection fraction

Recent clinical trials have revealed that aggressive insulin treatment has a neutral effect on cardiovascular risk in patients with diabetes despite improved glycemic control, which may suggest confounding direct effects of insulin on the human vasculature. We studied 580 patients with coronary atherosclerosis undergoing coronary artery bypass surgery (CABG), finding that high endogenous insulin was associated with reduced nitric oxide (NO) bioavailability ex vivo in vessels obtained during surgery. Ex vivo experiments with human internal mammary arteries and saphenous veins obtained from 94 patients undergoing CABG revealed that both long-acting insulin analogs and human insulin triggered abnormal responses of post-insulin receptor substrate 1 downstream signaling ex vivo, independently of systemic insulin resistance status. These abnormal responses led to reduced NO bioavailability, activation of NADPH oxidases, and uncoupling of endothelial NO synthase. Treatment with an oral dipeptidyl peptidase 4 inhibitor (DPP4i) in vivo or DPP4i administered to vessels ex vivo restored physiological insulin signaling, reversed vascular insulin responses, reduced vascular oxidative stress, and improved endothelial function in humans. The detrimental effects of insulin on vascular redox state and endothelial function as well as the insulin-sensitizing effect of DPP4i were also validated in high-fat diet-fed ApoE-/- mice treated with DPP4i. High plasma DPP4 activity and high insulin were additively related with higher cardiac mortality in patients with coronary atherosclerosis undergoing CABG. These findings may explain the inability of aggressive insulin treatment to improve cardiovascular outcomes, raising the question whether vascular insulin sensitization with DPP4i should precede initiation of insulin treatment and continue as part of a long-term combination therapy.

Coronary occlusion is a rare but well-described complication of heart valve surgery. The left circumflex coronary artery, especially when it is dominant, is particularly at risk owing to the proximity of the mitral valve annulus. We report three cases of acute coronary complications of different valvular surgical procedures diagnosed and treated in the cardiac catheterization laboratory. Intracoronary optical coherence tomography was used to identify the cause of coronary flow impairment and provided important insights into the mechanism of intraoperative vascular damage.

Introduction Myocardial creatine kinase (CK) activity represents an important metabolic reserve: it correlates closely with contractile reserve and post-ischaemic function, keeps cytosolic [ADP] low, and optimises the free energy for ATP hydrolysis. It may also contribute to the transition to failure in the heart hypertrophied by chronic haemodynamic overload; modest up-regulation has been shown to be cardio-protective. Total CK activity measurement requires chemical freeze-and-extract methods, which destroy tissue, precluding repeated measures. To date, non-invasive assessments of human myocardial CK flux (calculated as kf × [PCr], where kf is the pseudo-first-order forward rate constant measured by 31P-magnetic resonance spectroscopy (MRS) have not assessed creatine content or total CK activity. Thus we aimed to validate kf measurement against total CK activity and investigate predictors of CK activity. Methods 39 subjects (median age 71, range 43–84) undergoing clinically indicated cardiac surgery had CK total activity measured from LV biopsy. 31 had severe AS (10 with impaired LVEF); 2 had severe primary MR; 5 had severe mitral stenosis (2 with impaired LVEF) and 1 had an LA mass. 35 of 39 contributed triplicate datasets: CK total activity, kf (31P-MRS TRiST sequence at 3T) and LV volumes (cine-MRI, 3T Siemens). 27 had severe AS (8 with impaired LVEF); other groups were the same. Exclusion criteria were prior myocardial infarction and flow-limiting coronary disease. Flash-frozen LV biopsies obtained within 15 min of cardiopulmonary bypass were analysed for CK total activity, total creatine, and citrate synthase (CS) activity (a marker of oxidative phosphorylation capacity). Results Multiple, novel correlations were observed between CK total activity (IU/mg protein) and CS activity (r=0.87, p=9e-13), total creatine (r=0.59, p=8e-5), kf (r=0.42, p=0.013), total creatine × kf (r=0.64, p=4e-5), LVESVi (r=−0.52, p=8e-4), LVEF (r=0.48, p=0.002) and LVMi (r=−0.42, p=0.009) (Panels A-E) (LVEDVi and non-indexed counterparts were also significant correlates.) The most predictive linear regression model incorporating elements of the CK rate equation included total creatine (nmol/mg protein), kf (/s), and kf × LVESVi (ml/m2) (adjusted R2=0.56, beta=0.426, 0.618, −1.968 and p=0.001, 5e-5, 0.003 respectively, Panel F). Figure 1 Conclusions These results are the first evidence of agreement between non-invasive estimates of human cardiac CK activity (kf) and freeze-extracted chemical methods. The key original finding is that it is feasible to attempt to predict CK capacity in vivo by using a combination of techniques (creatine by 1H MRS, CK kf by 31P-MRS and LVESVi by cine imaging). The key insight is that CK capacity is best estimated not simply from what the rate equation would predict (creatine and kf), but that other factors relating to failing contractility reduce CK activity independently from creatine content and enzyme kf. Acknowledgement/Funding British Heart Foundation Clinical Research Training Fellowship (FS/15/80/31803) and Programme Grant (RG/18/12/34040).

Introduction The transition to systolic failure in severe aortic stenosis (AS) increases mortality. There are currently no reliable markers of transition, and the guideline LVEF Methods 19 patients with severe AS, LVEF ≥55% (AS-pEF, mean±SD LVEF 63±5%, mean gradient 48±14 mmHg) and 10 with severe AS, LVEF Results When compared to controls, both CK total activity and CS activity were lower in AS-pEF (by 27% and 23% respectively, both p AS-rEF was associated with further reduction in both CK and CS activities (by 32% and 22% respectively, both p When median mitochondria-sarcomere ATP diffusion distances were plotted against CK total activity a strong positive correlation was observed (r=0.86, p=0.003, Panel F). This suggests a compensatory reduction in diffusion distance develops when CK activity falls. Conclusions Transition to failure in severe AS is associated with lower oxidative capacity and maximal ATP delivery capacity through CK. Despite compensatory falls in ATP diffusion distance and altered CK isozyme expression, these changes may underlie susceptibility to EF decline in AS. Acknowledgement/Funding British Heart Foundation Clinical Research Training Fellowship (FS/15/80/31803) and Programme Grant (RG/18/12/34040).

Background Wnt5a is a non-canonical Wnt ligand with potential vascular effects, but its mechanistic role in atherosclerosis progression and the underlying downstream mechanisms are poorly explored. Purpose To address the hypothesis that Wnt5a induces vascular NADPH-oxidases activity, endothelial dysfunction and detrimental downstream redox signalling which could propagate atherosclerosis in humans. Methods Study 1 included 70 patients with coronary artery disease (CAD) versus age- and sex-matched non-CAD controls. Study 2 included 1,003 CAD patients undergoing cardiac surgery; internal mammary artery (IMA) and saphenous vein (SV) segments were harvested and used for ex vivo experiments. Study 3 included 68 individuals undergoing two cardiac computed tomography scans 3–5 years apart; calcified plaque burden was assessed by coronary calcium score (CCS). Superoxide (O2·−) generation was measured by lucigenin chemiluminescence with NADPH 100μM stimulation as indicator of NADPH-oxidases activity. Activation of Rac1, a key NADPH-oxidases subunit, was evaluated by a commercially available kit. Primary vascular smooth muscle cells (VSMCs) and HeLa cells were used for in vitro experiments. Circulating Wnt5a and Sfrp5 (a Wnt5a antagonist) were measured by ELISA in fasting plasma samples. Results In Study 1, the presence of CAD was independently linked with increased circulating Wnt5a bioavailability (A), which was, in turn, associated with increased IMA NADPH-oxidases activity in Study 2 (B). Recombinant Wnt5a directly stimulated NADPH-oxidases activity (C) via Rac1 activation (not shown) in human IMA, while inducing endothelial dysfunction evidenced by impaired SV endothelium-dependent acetylcholine (Ach) vasorelaxations (D). Transcriptomic analysis in Wnt5a-treated primary VSMCs versus controls identified USP17, a deubiquitinating enzyme implicated in Rac1 activation, as the top differentially regulated hit (not shown). Indeed, Wnt5a stimulated USP17 upregulation in VSMCs which was reversed by PEGylated superoxide dismutase (peg-SOD) 300U/mL (E), suggesting a redox sensitive effect. USP17 knockdown abolished the ability of Wnt5a to induce Rac1 activation in HeLa cells (F). At a clinical level, plasma Wnt5a was a predictor of plaque progression (defined as ΔCCS≥1, G) and new onset calcification (H) in Study 3. Conclusions We demonstrate for the first time that Wnt5a is elevated in CAD and causally associated with increased vascular oxidative stress and endothelial dysfunction in humans. We further reveal USP17 to be a novel, previously undescribed, link between Wnt5a, Rac1 activation and NADPH-oxidase activity induction in humans. We finally propose that circulating Wnt5a may have a clinically relevant role in predicting atherosclerosis progression. Our findings identify Wnt5a as rational therapeutic target in vascular disease. Acknowledgement/Funding British Heart Foundation; Alexandros S Onassis Public Benefit Foundation

Background NADPH oxidase activity is a major source of superoxide anions (O2·−) in the human myocardium, linked with adverse short-term clinical outcomes after cardiac surgery, but its prognostic value for the long-term clinical outcome of these patients is unknown. Purpose To explore the association between NADPH oxidase activity in the human myocardium and the clinical outcome of patients undergoing cardiac surgery. Methods A total of 216 patients from the Oxford Heart Vessels and Fat (OxHVF) cohort were enrolled. Myocardial tissue samples were collected during cardiac surgery and used for RNA isolation and myocardial O2·− quantification using lucigenin-enhanced chemiluminescence (5μmol/L). The specific contribution of NADPH oxidase activity to myocardial O2·− production was quantified as the Vas287021 (40 μmol/L)-inhibitable signal following NADPH (100μmol/L) stimulation (Vas2870 is a NADPH oxidases inhibitor). Malonyldialdehyde and hsCRP levels were measured in plasma isolated from peripheral blood collected pre-operatively. Patients were followed-up for a mean of 2.9±1.4 years for the primary endpoint of cardiovascular mortality. Results Myocardial NADPH oxidase activity was not correlated with systemic oxidative stress (evidenced by malonyldialdehyde, panel A) or systemic inflammation (reflected by hsCRP levels, panel B). NADPH oxidase activity was significantly higher in the cardiovascular death group (panel C) and was associated with cardiovascular (HR [95% CI]: 1.53 [1.10–2.13], p=0.01 per SD increase) but not all-cause mortality (HR [95% CI]: 1.32 [0.96–1.80], p=0.08 per SD increase). This association remained significant after adjustment for EuroscoreII (HR [95% CI]: 1.80 [1.14–2.82], p=0.01 per SD increase). For an optimal cut-off value of 7,920 RLU/sec/mg tissue, patient survival was significantly poorer in the high vs. low NADPH oxidase activity subgroup (panel D). Adding NADPH oxidase activity to the baseline clinical model significantly improved model's performance (panel E). Interestingly, myocardial NOX gene expression levels didn't show any significance in mortality prediction, highlighting the fact that NADPH oxidase activity, rather than enzyme levels, is the key outcomes regulator. Conclusion Increased NADPH oxidase activity in the human myocardium independently predicts high cardiovascular mortality in patients with advanced coronary atherosclerosis. Targeting NADPH oxidase in the human heart may be a rational therapeutic approach. Acknowledgement/Funding BHF, EPSRC

Obesity is associated with changes in the secretome of adipose tissue (AT), which affects the vasculature through endocrine and paracrine mechanisms. Wingless-related integration site 5A (WNT5A) and secreted frizzled-related protein 5 (SFRP5), adipokines that regulate noncanonical Wnt signaling, are dysregulated in obesity. We hypothesized that WNT5A released from AT exerts endocrine and paracrine effects on the arterial wall through noncanonical RAC1-mediated Wnt signaling. In a cohort of 1004 humans with atherosclerosis, obesity was associated with increased WNT5A bioavailability in the circulation and the AT, higher expression of WNT5A receptors Frizzled 2 and Frizzled 5 in the human arterial wall, and increased vascular oxidative stress due to activation of NADPH oxidases. Plasma concentration of WNT5A was elevated in patients with coronary artery disease compared to matched controls and was independently associated with calcified coronary plaque progression. We further demonstrated that WNT5A induces arterial oxidative stress and redox-sensitive migration of vascular smooth muscle cells via Frizzled 2-mediated activation of a previously uncharacterized pathway involving the deubiquitinating enzyme ubiquitin-specific protease 17 (USP17) and the GTPase RAC1. Our study identifies WNT5A and its downstream vascular signaling as a link between obesity and vascular disease pathogenesis, with translational implications in humans.

Objectives Early saphenous vein graft (SVG) occlusion is typically attributed to technical factors. We aimed at exploring clinical, anatomical, and operative factors associated with the risk of early SVG occlusion (within 12 months postsurgery). Methods Published literature in MEDLINE was searched for studies reporting the incidence of early SVG occlusion. Individual patient data (IPD) on early SVG occlusion were used from the SAFINOUS-CABG Consortium. A derivation (n = 1492 patients) and validation (n = 372 patients) cohort were used for model training (with 10-fold cross-validation) and external validation respectively. Results In aggregate data meta-analysis (48 studies, 41,530 SVGs) the pooled estimate for early SVG occlusion was 11%. The developed IPD model for early SVG occlusion, which included clinical, anatomical, and operative characteristics (age, sex, dyslipidemia, diabetes mellitus, smoking, serum creatinine, endoscopic vein harvesting, use of complex grafts, grafted target vessel, and number of SVGs), had good performance in the derivation (c-index = 0.744; 95% confidence interval [CI], 0.701-0.774) and validation cohort (c-index = 0.734; 95% CI, 0.659-0.809). Based on this model. we constructed a simplified 12-variable risk score system (SAFINOUS score) with good performance for early SVG occlusion (c-index = 0.700, 95% CI, 0.684-0.716). Conclusions From a large international IPD collaboration, we developed a novel risk score to assess the individualized risk for early SVG occlusion. The SAFINOUS risk score could be used to identify patients that are more likely to benefit from aggressive treatment strategies.

Myocardial perfusion reserve is impaired in aortic stenosis (AS) even in the absence of epicardial coronary stenosis [(1)][1], which may be due to reduced capillary density and endothelial dysfunction [(2,3)][2]. However, the relationship between histopathological abnormalities of the vasculature

OBJECTIVES To identify clinical and procedural practice predictors of avoidable complications during transcatheter aortic valve replacement (TAVR). BACKGROUND TAVR is evolving as a viable strategy for treatment of aortic stenosis (AS). Vascular complications, major bleeding, or pericardial tamponade may be influenced by procedural practice. METHODS The Oxford TAVR (OxTAVI) prospective registry was retrospectively analyzed to identify predictors of avoidable procedural complications in a contemporary cohort of transfemoral TAVR between January 2015 and September 2018. The primary endpoint was defined as a hierarchic composite of in-hospital mortality, pericardial effusion/cardiac tamponade, major bleeding, and vascular access complications. Individual components of the primary endpoint have been analyzed separately. RESULTS Five-hundred-twenty-nine patients underwent transfemoral TAVR using contemporary techniques during the study period and were enrolled in the OxTAVI registry. Female sex and high frailty were associated with a higher risk of death, major bleeding, vascular complication or pericardial tamponade. The use of ultrasound (US) guidance for vascular access management was independently associated with a reduced composite primary endpoint (OR = 0.35, CI:0.14-0.86, p = .02) after adjustment for clinical confounders, largely driven by a threefold reduction in vascular access complication (OR = 0.29, CI:0.15-0.55, p

Background Impaired myocardial perfusion reserve occurs in pressure overload hypertrophy such as in severe aortic stenosis (AS) despite unobstructed epicardial coronaries. However the pathological mechanisms underlying this are poorly understood. We sought to assess myocardial perfusion reserve in severe AS by stress perfusion cardiovascular magnetic resonance (CMR), and examine the findings in relation to the histological evidence of vascular changes in the myocardium. Methods Fourteen patients with severe AS and unobstructed epicardial coronaries underwent adenosine stress perfusion CMR before and 6 months after surgical aortic valve replacement (AVR). Myocardial biopsies were obtained during AVR and stained using CD31 +for endothelium, smooth muscle actin (SMA) for smooth muscle, and picrosirius red for fibrosis. Nine age- and sex- matched post-mortem myocardial samples served as histological controls. Results When compared to controls, the myocardium of patients with severe AS had reduced vessel density, total quantity of SMA +ve and CD31 +ve, in addition to the expected increase in fibrosis. There was absence of CD31 +ve endothelium in SMA +ve arterioles, indicating endothelial loss. (Figure 1) Importantly, patients with an aortic valve area (AVA) ≤0.8cm2 had greater endothelial loss compared to those with an AVA >0.8 and≤1.0cm2 (1.34%±0.44% vs 2.84±1.03%, p=0.006), and endothelial loss also correlated with myocardial perfusion reserve index (MPRI), r=0.66, p=0.019. MPRI improved significantly post AVR (from 0.95±0.17 to 1.50±0.43, p=0.018). Conclusion In severe AS, there is microvascular rarefaction and loss of endothelium, which is more pronounced in patients with the most severe aortic valve narrowing. This appears to be an underlying mechanism for reduced myocardial perfusion reserve, which may be reversible post AVR.

Type A aortic dissection is a rare but important cardiac surgical emergency. Few reports exist in the literature describing anterior spinal artery syndrome as a presenting feature. We report a case of anterior spinal artery syndrome due to aortic dissection in a patient with Marfan syndrome caused by a novel fibrillin mutation. A 53-year old female presented with chest pain and sudden-onset paralysis. Neurological examination revealed normal upper limb examination, reduced lower limb power and reflexes but normal sensation. CT scanning revealed type A acute aortic dissection which was treated with emergent cardiac surgical repair. At clinic follow up 3 years later, signs of Marfan syndrome were opportunistically noted and genetic testing revealed a novel mutation in the Fibrillin 1 gene. This case emphasises the importance of a good initial clinical assessment, including thorough neurological examination, as well as a low threshold of clinical suspicion for an aortic dissection in such a constellation of symptoms. The importance of family history should also be emphasised given the coincidental diagnosis of Marfan syndrome in a first-degree relative. Furthermore, this case illustrates the classical signs of anterior spinal artery syndrome.

Background Insulin may have protective roles in vascular cells, but its vascular effects in patients with atherosclerosis are unknown. Dipeptidyl peptidase 4 (DPP4) inhibitors are a class of insulin-sensitising agents that may regulate vascular responses to insulin in humans. We attempted to determine the direct vascular effects of insulin in humans with atherosclerosis, and explore the effect of DPP4 inhibition on vascular insulin signalling. Methods The study included 613 patients undergoing coronary bypass surgery. Vascular segments (internal mammary arteries (IMA), saphenous veins (SV)) were collected and incubated with insulin glargine active metabolite M1 (insulin), insulin degludec (DEG) and human insulin (HI) (1–100 nM as stated), with or without pre-incubation with KR62436 (a DPP4 inhibitor) at 70 µM. Vascular superoxide (O2.-) was quantified by lucigenin chemiluminescence, while nitric oxide bioavailability was evaluated by quantifying the vasorelaxations to acetylcholine. Circulating DPP4 activity was measured in fasting serum using commercially available kits. Downstream signalling was evaluated by Western blotting for protein phosphorylation. Results Insulin increased NADPH-oxidases-derived O2.- in vessels from patients with or without diabetes, an effect reversed in vascular segments from diabetic patients pre-treated with an oral DPP4 inhibitor (A). In contrast, insulin reduced O2.- in vessels of healthy mice used as controls (not shown). Circulating DPP4 activity was associated with increased vascular NADPH-oxidases activity in the study population (not shown), while ex vivo pre-incubation of human vessels with KR62436 (DPP4-i) reversed the effect of insulin on vascular O2.-, supressing NADPH-oxidases activity (B), improving eNOS coupling (C) and ameliorating endothelial dysfunction in human vessels (D). This was a class effect, replicated using DEG and HI (data not shown). DPP4 inhibition improved downstream insulin signalling by reducing insulin receptor substrate 1 (IRS1) phosphorylation at Ser307, a site linked to molecular insulin resistance (E). The vascular effects of DPP4 inhibition may be regulated via AMPK, since DPP4-i increased AMPK Thr172 phosphorylation while AMPK inhibition with compound C reversed the protective vascular effects of DPP4-I (F). Conclusions We demonstrate for the first time that insulin induces oxidative stress and endothelial dysfunction in vascular segments from patients with atherosclerosis, independently of systemic insulin resistance. This may partially explain the inability of insulin treatment to improve cardiovascular outcomes in patients with moderately elevated blood glucose. Pre-treatment with a DPP4 inhibitor restores local insulin sensitivity modulating the vascular responses to insulin. These findings suggest that vascular sensitisation may be crucial when treating of diabetic patients in secondary prevention.

Biological age is a better measure of functional capacity than chronological age.1 One of the measures of biological age is telomere length. Telomeres are nucleoprotein complexes that protect chromosome ends from damage. The DNA component of telomeres progressively shortens as biological age increases and thus acts as a read out for ‘miles on the biological clock’. 2 Telomere length progressively shortens as biological age increases. Within health care, ageing is almost exclusively described in terms of chronological age. Recent studies explored using biological age to stratify patients and predict outcomes.3 This project acts as a pilot study to investigate whether biological age is related to intensive care unit (ICU) outcomes and whether ICU patients age biologically at an accelerated rate. This project used blood samples from a previous study where patients underwent cardiac surgery and were admitted to the ICU. Blood samples were obtained before surgery and on days 1, 2, and 3 after surgery. The database contained the following physiological parameters: haemoglobin, urea, creatinine, RIFLE score, length of ICU stay, and whether renal replacement therapy was required. Information on co-morbidities and medication was also provided. DNA was isolated using a Maxwell machine and telomere length determined via quantitative PCR. One hundred and fifty-five blood samples from 46 patients underwent analysis. Telomere length did not differ significantly over the 4 days (P=0.662). No relationship was found between telomere length and any physiological parameter, co-morbidity, or medication. There was a trend towards significance with RIFLE score at day 3 increasing as telomere length decreased, although this was not statistically significant (P=0.09). No relationship between telomere length and the available physiological parameters, comorbidities, or medication was found. Telomere length did not vary during ICU stay. This study was limited by its small sample size. Future studies would benefit from a larger sample size; in addition, blood samples could also be obtained at 6 months after discharge to allow gradual alterations in biological age to be determined. Recent studies give evidence that telomere length is a weak biomarker of ageing,3 and that more meaningful data might be obtained using superior markers, such as CDKN2A expression or expression levels of non-coding RNAs.3

Background: Non-invasive detection of vascular inflammation remains an unmet goal. We hypothesized that phenotypic changes in perivascular adipose tissue (PVAT) induced by vascular inflammation can be quantified using a new computed tomography angiography (CTA) methodology. Methods: In Arm 1, human PVAT adipocytes were cultured +/- inflammatory cytokines (n=7) or co-cultured with vascular tissue (+/-Angiotensin-II, n=6) to assess the effects of vascular inflammation on PVAT differentiation. In Arm 2, AT explants (epicardial, subcutaneous and thoracic AT) from 453 cardiac surgery patients were used in histology and gene expression studies to relate the ex vivo images with in vivo CT scan information (n=105) on the biology of the explants. In Arm 3, in 267 patients undergoing diagnostic CTA, PVAT attenuation (Fat Attenuation Index (FAI) defined as the average CT attenuation of AT), was analysed around the proximal right coronary artery. In Arm 4, PVAT FAI around unstable (culprit) and stable coronary plaques was calculated in 22 CAD patients undergoing CTA. Results: In Arm 1, Angiotensin-II (A) and proinflammatory cytokines (B) prevented lipid accumulation and adipocyte differentiation in cultured PVAT. In Arm 2, adipocyte size by histology was inversely correlated with FAI in vivo (C). Both FAI of AT explants (not shown) and FAI in-vivo (n=105) were negatively associated with epicardial AT differentiation as assessed by FABP4 expression (D). In Arm 3, PVAT FAI change over distance from RCA wall was significantly different in CAD compared to no CAD patients (E). In Arm 4, PVAT FAI was significantly increased around unstable plaques (F). Conclusions: Human vessels exert paracrine effects on surrounding PVAT, affecting local intracellular lipid accumulation in preadipocytes, which can then be monitored using a CT imaging approach. This novel methodology can be implemented in clinical practice to detect unstable plaques in the human coronary vasculature.

Background / Purpose The Lotus valve (Boston Scientific, Natick, MA, USA) is a contemporary transcatheter aortic valve implantation (TAVI) device that is fully repositionable and retrievable to aid implantation and optimise procedural results. The ability to implant the device without routine pre-dilatation is another possible advantage reducing associated risks and procedure times. The aim of this study is to report procedural and 30-day outcomes following TAVI in a consecutive patient group presenting with severe symptomatic aortic stenosis with the Lotus valve system without routine pre-dilatation. Methods / Materials 146 consecutive patients that underwent TAVI at the John Radcliffe Hospital, Oxford between January 2015 – December 2016 were retrospectively analysed. Results The mean age was 81.1 ± 7.4 years and the mean logistic EuroSCORE was 14.6 ± 10. 134 (91.8%) of patients were treated under conscious sedation. 144 (98.6%) of procedures were successful. Two patients (1.4%) died during the follow-up period. None or mild residual aortic regurgitation was achieved in 98.6% of patients. The mean and peak transvalvular gradients were 8.6 ± 3.6mmHg and 16.6 ± 6.6mmHg respectively. Eight patients (5.5%) suffered a stroke. Over time, there was a reduction in major vascular complications (14.3% vs. 2.2%, p = 0.03) and a trend toward shorter procedure times (97.6 ± 44.3 vs. 86.8 ± 31.4 minutes, p = 0.14) and the administration of less contrast (104.4 ± 45.2 vs. 91.7 ± 37.6 millilitres, p = 0.16). The overall new pacemaker implantation rate was 36.3%. Conclusions The use of the Lotus valve as a ‘workhorse’ device without routine pre-dilatation is safe and efficacious and is associated with a very low incidence of residual aortic regurgitation and acceptable transvalvular haemodynamics.

Early detection of vascular inflammation is a long-standing goal that would allow deployment of targeted strategies for the prevention or treatment of multiple disease states. Since vascular inflammation is not detectable with commonly used imaging modalities, we hypothesized that phenotypic changes in perivascular adipose tissue (PVAT) induced by vascular inflammation could be quantified using a new computerized tomography angiography (CTA) methodology. We show that inflamed human vessels release cytokines that prevent lipid accumulation in PVAT-derived preadipocytes in vitro, ex vivo and in vivo. We developed a 3D PVAT analysis method and studied CT images of human adipose tissue explants from 453 patients undergoing cardiac surgery, relating the ex vivo images with in vivo CT scan information on the biology of the explants. We have developed a new imaging biomarker, CT Fat attenuation index (FAI), that describes adipocyte lipid content and size. FAI has excellent sensitivity and specificity for detecting tissue inflammation as assessed by tissue uptake of 18FFDG in positron emission tomography (PET). In a validation cohort of 273 subjects, the FAI gradient around the human coronary arteries identified early subclinical coronary artery disease in vivo, and detected dynamic changes of PVAT in response to variations of vascular inflammation, and inflamed, vulnerable atherosclerotic plaques during acute coronary syndromes. Our study revealed that human vessels exert paracrine effects on the surrounding PVAT, affecting local intracellular lipid accumulation in preadipocytes, which can then be monitored using a CT imaging approach. This methodology can be implemented in clinical practice to allow the non-invasive detection of unstable plaques in the human coronary vasculature.

OBJECTIVE: Transcatheter aortic valve implantation (TAVI) has been adopted rapidly in Europe. TAVI national registries can augment understanding of technologies and represent real-world experience, providing further clinical insights. We undertook a meta-analysis of published European national TAVI registries to assess current results following TAVI in Europe.METHODS: Electronic databases were searched. The review focused on the comparison of the following TAVI strategies: transfemoral (TF) and transapical (TA) SAPIEN and CoreValve implantation. Individual event rates for outcomes of interest were pooled using a mixed effect model.RESULTS: Seven European national TAVI registries (UK, Swiss, Belgium, Italy, Spain, France, Germany) were identified, including a total of 9786 patients who received TF-SAPIEN (n = 2885), TA-SAPIEN (n = 2252) and CoreValve (n = 4649) implantation. Pooled incidence of 30-day mortality was 0.08% [95% Confidence Interval (CI): 0.05-0.11], 0.12% [95% CI: 0.07-0.19] and 0.06% [95% CI: 0.03-0.11] for TF-SAPIEN, TA-SAPIEN and CoreValve respectively (test for subgroup difference P = 0.18); there was high heterogeneity across European countries. Pooled incidence of stroke was comparable among the TAVI strategies (test for subgroup difference P = 0.79); the incidence of post-procedural moderate paravalvular leak ≥ 2 (P = 0.9) was similar across groups. CoreValve implantation was associated with an increased risk of pacemaker implantation (0.22 [95% CI: 0.19-0.26]; test for subgroup difference P CONCLUSIONS: Transarterial TAVI approaches were associated with a low early mortality regardless of the type of device used. There was marked heterogeneity among European countries for early mortality.

Background Tetrahydrobiopterin (BH4), a critical endothelial nitric oxide synthase (eNOS) cofactor, is an important determinant of endothelial function. Oral BH4 therapy has been proposed as a treatment for vascular disease. We investigated the pharmacokinetics and pharmacodynamics of oral BH4 in both plasma and vascular tissue to determine whether oral BH4 therapy would improve vascular function in patients with established atherosclerosis and oxidative stress. Methods In a double-blind, randomised trial, 49 patients with coronary artery disease (CAD) awaiting coronary artery bypass graft surgery received oral BH4 700 mg/d (n=16) or 400 mg/d (n=14), or placebo (n=19), for a mean duration of 30 days prior to surgery. Biopterin levels were measured in plasma at baseline and after the treatment period, and in saphenous vein (SV) and internal mammary artery (IMA) tissue collected at the time of surgery. Vascular superoxide and endothelial function were measured ex vivo. Cardiovascular MRI was used to determine brachial artery flow-mediated dilatation and indices of arterial stiffness before and after treatment. Results Plasma BH4 levels were elevated threefold by both low- and high-dose BH4 treatment compared to placebo (p ex vivo , or in MRI indices of vascular function. Conclusion Although absolute BH4 levels in plasma and SV are increased, chronic oral BH4 therapy does not alter biopterin redox status (BH4:BH2 ratio) in either plasma or vascular tissue. Accordingly, oral BH4 does not improve vascular function or oxidative stress in patients with established CAD.

Background The management of atrial fibrillation remains a challenge. This condition remodels atrial electrical properties, which promote resistance to treatment. Although remodelling has long been a therapeutic target in atrial fibrillation, its causes remain incompletely understood. We aimed to evaluate the role of miR-31-dependent reduction in dystrophin and neuronal nitric oxide synthase (nNOS, also known as NOS1) on atrial electrical properties and atrial fibrillation inducibility. Methods We recruited 258 patients (209 patients in sinus rhythm and 49 with permanent atrial fibrillation) from the John Radcliffe Hospital, Oxford, UK; written informed consent was obtained from each participant. We also used a goat model of pacing-induced atrial fibrillation (24 with atrial fibrillation vs 20 controls in normal sinus rythm) and nNos-knock-out mice (n=28 compared with 27 wild-type littermates). Gene expression of miR-31, dystrophin, and nNOS was assessed by quantitative RT-PCR; protein content was measured by immunoblotting; NOS activity was evaluated with high-performance liquid chromatography; action potential duration (APD) and rate dependent adaptation were assessed by single-cell patch-clamping, and atrial fibrillation inducibility was evaluated by transoesophageal atrial burst stimulation. Findings We found that atrial-specific upregulation of miR-31 in human atrial fibrillation caused dystrophin ( DYS ) translational repression and accelerated mRNA degradation of nNOS leading to a profound reduction in atrial DYS and nNOS protein content and in nitric oxide availability. In human atrial myocytes obtained from patients in sinus rhythm, nNOS inhibition was sufficient to recapitulate hallmark features of remodelling induced by atrial fibrillation, such as shortening of APD and loss of APD rate-dependency, but had no effect in patients with atrial fibrillation. In mice, nNos gene deletion or inhibition shortened atrial APD and increased atrial fibrillation inducibility in vivo. Inhibition of miR-31 in human atrial fibrillation recovered DYS and nNOS, and normalised APD and APD rate-dependency. Prevention of miR-31 binding to nNOS 3′UTR recovered both nNOS protein and gene expression but had no effect on the DYS protein or mRNA level (consistent with the mRNA degradation of nNOS by miR-31). Prevention of miR-31 binding to DYS 3′UTR increased DYS protein but not mRNA is consistent with translation repression of DYS by miR-31; recovery of DYS protein increased nNOS protein but not mRNA in keeping with a stabilising effect of DYS on nNOS protein. In goats, a reduction in dystrophin and nNOS protein content was associated with upregulation of miR-31 in the atria but not in the ventricles. Interpretation The findings suggest that atrial-specific upregulation of miR-31 in human atrial fibrillation is a key mechanism causing atrial loss of dystrophin and nNOS; this loss leads to the electrical phenotype induced by atrial fibrillation. Funding British Heart Foundation (BHF) Programme grant (for BC and XL), BHF Centre of Excellence in Oxford (SR), Leducq Foundation (in part for BC and SR), the European Union's seventh Framework Programme Grant Agree.

Background— The endothelial nitric oxide synthase cofactor tetrahydrobiopterin (BH4) plays a pivotal role in maintaining endothelial function in experimental vascular disease models and in humans. Augmentation of endogenous BH4 levels by oral BH4 treatment has been proposed as a potential therapeutic strategy in vascular disease states. We sought to determine the mechanisms relating exogenous BH4 to human vascular function and to determine oral BH4 pharmacokinetics in both plasma and vascular tissue in patients with coronary artery disease. Methods and Results— Forty-nine patients with coronary artery disease were randomized to receive low-dose (400 mg/d) or high-dose (700 mg/d) BH4 or placebo for 2 to 6 weeks before coronary artery bypass surgery. Vascular function was quantified by magnetic resonance imaging before and after treatment, along with plasma BH4 levels. Vascular superoxide, endothelial function, and BH4 levels were determined in segments of saphenous vein and internal mammary artery. Oral BH4 treatment significantly augmented BH4 levels in plasma and in saphenous vein (but not internal mammary artery) but also increased levels of the oxidation product dihydrobiopterin (BH2), which lacks endothelial nitric oxide synthase cofactor activity. There was no effect of BH4 treatment on vascular function or superoxide production. Supplementation of human vessels and blood with BH4 ex vivo revealed rapid oxidation of BH4 to BH2 with predominant BH2 uptake by vascular tissue. Conclusions— Oral BH4 treatment augments total biopterin levels in patients with established coronary artery disease but has no net effect on vascular redox state or endothelial function owing to systemic and vascular oxidation of BH4. Alternative strategies are required to target BH4-dependent endothelial function in established vascular disease states. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00423280.

Experimental evidence suggests that telomere length (TL) is shortened by oxidative DNA damage, reflecting biological aging. We explore the value of blood (BTL) and vascular TL (VTL) as biomarkers of systemic/vascular oxidative stress in humans and test the clinical predictive value of BTL in acute myocardial infarction (AMI).In a prospective cohort of 290 patients surviving recent AMI, BTL measured on admission was a strong predictor of all-cause [hazard ratio (HR) [95% confidence interval (CI)]: 3.21 [1.46-7.06], P = 0.004] and cardiovascular mortality (HR [95% CI]: 3.96 [1.65-9.53], P = 0.002) 1 year after AMI (for comparisons of short vs. long BTL, as defined by a T/S ratio cut-off of 0.916, calculated using receiver operating characteristic analysis; P adjusted for age and other predictors). To explore the biological meaning of these findings, BTL was quantified in 727 consecutive patients undergoing coronary artery bypass grafting (CABG), and superoxide (O2.-) was measured in peripheral blood mononuclear cells (PBMNC). VTL/vascular O2.- were quantified in saphenous vein (SV) and mammary artery (IMA) segments. Patients were genotyped for functional genetic polymorphisms in P22ph°x (activating NADPH-oxidases) and vascular smooth muscle cells (VSMC) selected by genotype were cultured from vascular tissue. Short BTL was associated with high O2.- in PBMNC (P = 0.04) but not in vessels, whereas VTL was related to O2.- in IMA (ρ = -0.49, P = 0.004) and SV (ρ = -0.52, P = 0.01). Angiotensin II (AngII) incubation of VSMC (30 days), as a means of stimulating NADPH-oxidases, increased O2.- and reduced TL in carriers of the high-responsiveness P22ph°x alleles (P = 0.007).BTL predicts cardiovascular outcomes post-AMI, independently of age, whereas VTL is a tissue-specific (rather than a global) biomarker of vascular oxidative stress. The lack of a strong association between BTL and VTL reveals the importance of systemic vs. vascular factors in determining clinical outcomes after AMI.

Background: Systemic inflammation and increased myocardial production of reactive oxygen species (ROS) are associated with the development of postoperative atrial fibrillation (AF) and low cardiac output syndrome in patients undergoing cardiac surgery. Statins have been shown to exert rapid anti-inflammatory and antioxidant effects by inhibiting myocardial NOX2 oxidases and by increasing the bioavailability of nitric oxide (NO). Methods and Results: We first assessed the impact of cardiac surgery and cardiopulmonary bypass (CPB) on the atrial nitroso-redox balance in 116 patients and then investigated the effect of perioperative treatment with atorvastatin (80 mg once daily, for up to 6 days before surgery and 5 days thereafter) on nitric oxide synthase (NOS) activity, biopterin content, and the sources of ROS production (all by HPLC) in samples of the right atrial appendage obtained before and after CPB and reperfusion and on the postoperative atrial effective refractory period (AERP; by programmed electrical stimulation delivered using right atrial epicardial leads) in a placebo-controlled double-blind trial (ClinicalTrials.gov Identifier: NCT01780740) in 80 patients undergoing first-time elective cardiac surgery. Our findings show that increased ROS production by NOX2 and mitochondrial oxidases and uncoupling of the endothelial NOS isoform (eNOS), secondary to enzyme’s S-glutathionylation, are the main mechanism underlying the atrial nitroso-redox imbalance after CPB and reperfusion. Compared with placebo, atorvastatin prevented the rise in atrial NOX2 activity and maintained the functionally coupled status of eNOS. The AERP lengthened progressively over first four postoperative days and did not differ between the treatment groups (n= 29). Conclusions: Short-term statin therapy, at the dose conventionally used to lower LDL-cholesterol, prevents NOS uncoupling and nitroso-redox imbalance in the atrial myocardium of patients undergoing on-pump cardiac surgery. However, these changes have no significant impact on atrial refractoriness.

Background: Insulin resistance (IR) is associated with increased cardiovascular risk. Given that plasma endothelin (ET) is elevated in IR, we explored whether the variations in ET levels mediate the vascular complications of type 2 diabetes (T2DM), by exploring its links with vascular redox state in human vessels. Methods: The study population consisted of 383 patients undergoing coronary bypass surgery (CABG), 30% with T2DM. Levels of ET, insulin growth factor 1 (IGF1), insulin and glucose (to calculate HOMA-IR as an index of insulin resistance) were measured in plasma, while vascular superoxide (O2) was measured in saphenous vein segments obtained during surgery. Results: Patients with untreated T2DM had elevated plasma ET, contrary to treated patients with T2DM (A). A positive association was observed between plasma endothelin and IGF1 levels in non-T2DM, which was reversed in T2DM (B). Elevated plasma ET was associated with increased NADPH-stimulated O2- (indicative of higher NADPH oxidase activity) and more LNAME inhibitable O2- (suggestive of more eNOS uncoupling) in human vessels (C, D). Conclusions: We demonstrate that circulating ET is elevated in untreated T2DM but its levels are normalised after intensive glycaemic control. We also document a striking effect of DM on the balance between ET and IGF1, and we demonstrate for the first time in humans, that elevated plasma ET is associated with increased O2- generation in the vascular wall through activation of NADPH-oxidase and uncoupling of eNOS. This study shows that ET and its interplay with IGF1 is possibly a key mechanism linking T2DM with its vascular complications in humans