Association between lipoprotein(a), LPA genetic risk score, aortic valve disease, and subsequent major adverse cardiovascular events.

AIMS: Cohort studies have demonstrated associations between calcific aortic valve disease (CAVD) and Lp(a). As Lp(a) is almost entirely genetically determined, in this study, we aim to determine whether Lp(a), when predicted from genetic data, is associated with CAVD and major adverse cardiovascular events (MACEs). METHODS AND RESULTS: Patients undergoing coronary angiography between January 2012 and May 2013 were invited to participate in the study. Of 752 analysable participants, 446 had their Lp(a) measured and 703 had a calculable LPA genetic risk score (GRS). The primary outcomes were the presence of CAVD at baseline and MACE over a 7-year follow-up. The GRS explained 45% of variation in Lp(a). After adjustment for cardiac risk factors and coronary artery disease (CAD), the odds of CAVD increased with increasing Lp(a) [odds ratio (OR) 1.039 per 10-unit increase, 95% confidence interval (CI) 1.022-1.057, P < 0.001] and GRS (OR 1.054 per 10-unit increase, 95% CI 1.024-1.086; P < 0.001). Lipoprotein(a) and the GRS as continuous variables were not associated with subsequent MACEs. A dichotomized GRS (>54) was associated with MACE, but this relationship became non-significant when CAD classification was added into the model (OR 1.333, 95% CI 0.927-1.912; P = 0.12). CONCLUSION: An LPA GRS can explain 45% of variation in Lp(a) levels, and both Lp(a) and the GRS are associated with CAVD. An elevated GRS is associated with future cardiac events in a secondary risk setting, but, if the CAD status is known, it does not provide additional prognostic information.

Lipoprotein (a) [Lp(a)] is a type of cholesterol that is determined almost entirely by genetics. It is associated with heart disease and also stiffening of the heart valves. Recent advancements have made it possible to predict Lp(a) levels by analysing a person's DNA. This study examines the association between genetically predicted Lp(a) and adverse outcomes. Genetically predicted Lp(a) accounts for 45% of the variability in the actual Lp(a) level.Both actual and genetically predicted Lp(a) are associated with heart valve disease and adverse heart outcomes. If the degree of narrowing of the arteries in the heart is already known, genetically predicted Lp(a) does not help further predict risk.

Outcomes of patients with early calcific aortic valve disease detected by clinically indicated echocardiography.

AIMS: Previous studies have demonstrated relatively slow rates of progression of early calcific aortic valve disease (CAVD), which encompasses aortic sclerosis (ASc) and mild aortic stenosis (AS). The potential evolution to clinically significant AS is unclear, and we therefore examined the long-term outcomes of patients with ASc and mild AS detected at the time of clinically indicated echocardiography. METHODS AND RESULTS: Data from initial clinically indicated echocardiograms performed between 2010 and 2018 in patients aged ≥18 years were extracted and linked to nationally collected outcome data. Those with impaired right or left systolic ventricular function or other significant left-sided valve disease were excluded. A time to first event analysis was performed with a composite primary outcome of cardiovascular death and aortic valve intervention (AVI). Of the 13 313 patients, 8973 had no CAVD, 3436 had ASc, and 455 had mild AS. The remainder had moderate or worse stenosis. Over a median follow-up period of 4.2 (interquartile range 1.8-6.7) years (and after adjustment for age and sex), those with ASc were at greater risk of the primary outcome [hazard ratio (HR) 2.9, 95% confidence interval (CI) 2.1-4.0] and need for AVI (HR 26.8, 95% CI 9.1-79.1) compared with those with no CAVD. Clinical event rates accelerated after ∼5 years in those with mild AS. CONCLUSION: Patients with ASc are >25 times more likely to require AVI than those with no CAVD, and follow-up echocardiography should be considered within 3-4 years in those with mild AS.

Upper-Limb High-Intensity Interval Training or Passive Heat Therapy to Optimize Cardiorespiratory Fitness Prior to Total Hip or Knee Arthroplasty: A Randomized Controlled Trial.

OBJECTIVE: Preoperative exercise training, or prehabilitation, aims to optimize cardiorespiratory fitness before surgery to reduce the risk of adverse perioperative events and delayed recovery. However, traditional exercise such as walking and cycling can be difficult for people with degenerative joint diseases of the lower limbs, such as osteoarthritis. The purpose of this study was to compare the effect of three low-impact interventions on cardiorespiratory fitness, physical function, and subjective health before total hip or knee arthroplasty. METHODS: This was a randomized controlled trial involving 93 participants with severe knee or hip osteoarthritis awaiting joint replacement surgery. Participants underwent cardiopulmonary exercise testing (to measure peak oxygen consumption [ V ̇ $$ \dot{V} $$ O2 ]), then were randomized to heat therapy (Heat; 20-30 min immersed in 40°C water followed by ~15 min light-resistance exercise), high-intensity interval training (HIIT; 6-8 × 60 s intervals on a cross-trainer or arm ergometer at ~90%-100% peak V ̇ $$ \dot{V} $$ O2 ), or home-based exercise (Home; ~15 min light-resistance exercise); for up to 36 sessions (3 sessions per week for 12 weeks). RESULTS: Peak V ̇ $$ \dot{V} $$ O2 increased by 16% across HIIT and to a greater extent than Heat (+2.5 mL × min-1 × kg-1 [95% CI: 0.5-4.4], P = 0.009) and Home (+3.2 mL × min-1 × kg-1 [1.2-5.2], P = 0.001). The anaerobic threshold increased across HIIT (+1.5 mL × min-1 × kg-1 [0.7-2.3], P < 0.001) and Heat (+1.2 mL × min-1 × kg-1 [0.4-1.9], P = 0.004), but not Home (-0.5 mL × min-1 × kg-1 [-1.3 to 0.3], P = 0.248). Subjective severity of osteoarthritis was unchanged with any intervention (P ≥ 0.250). CONCLUSION: Heat therapy and HIIT improved indices of cardiorespiratory fitness preoperatively in patients who have difficulty performing lower-limb exercise.

Plasminogen Receptors Promote Lipoprotein(a) Uptake by Enhancing Surface Binding and Facilitating Macropinocytosis.

BACKGROUND: High levels of Lp(a) (lipoprotein(a)) are associated with multiple forms of cardiovascular disease. Lp(a) consists of an apoB100-containing particle attached to the plasminogen homologue apo(a). The pathways for Lp(a) clearance are not well understood. We previously discovered that the plasminogen receptor PlgRKT (plasminogen receptor with a C-terminal lysine) promoted Lp(a) uptake in liver cells. Here, we aimed to further define the role of PlgRKT and to investigate the role of 2 other plasminogen receptors, annexin A2 and S100A10 (S100 calcium-binding protein A10) in the endocytosis of Lp(a). METHODS: Human hepatocellular carcinoma (HepG2) cells and haploid human fibroblast-like (HAP1) cells were used for overexpression and knockout of plasminogen receptors. The uptake of Lp(a), LDL (low-density lipoprotein), apo(a), and endocytic cargos was visualized and quantified by confocal microscopy and Western blotting. RESULTS: The uptake of both Lp(a) and apo(a), but not LDL, was significantly increased in HepG2 and HAP1 cells overexpressing PlgRKT, annexin A2, or S100A10. Conversely, Lp(a) and apo(a), but not LDL, uptake was significantly reduced in HAP1 cells in which PlgRKT and S100A10 were knocked out. Surface binding studies in HepG2 cells showed that overexpression of PlgRKT, but not annexin A2 or S100A10, increased Lp(a) and apo(a) plasma membrane binding. Annexin A2 and S100A10, on the other hand, appeared to regulate macropinocytosis with both proteins significantly increasing the uptake of the macropinocytosis marker dextran when overexpressed in HepG2 and HAP1 cells and knockout of S100A10 significantly reducing dextran uptake. Bringing these observations together, we tested the effect of a PI3K (phosphoinositide-3-kinase) inhibitor, known to inhibit macropinocytosis, on Lp(a) uptake. Results showed a concentration-dependent reduction confirming that Lp(a) uptake was indeed mediated by macropinocytosis. CONCLUSIONS: These findings uncover a novel pathway for Lp(a) endocytosis involving multiple plasminogen receptors that enhance surface binding and stimulate macropinocytosis of Lp(a). Although the findings were produced in cell culture models that have limitations, they could have clinical relevance since drugs that inhibit macropinocytosis are in clinical use, that is, the PI3K inhibitors for cancer therapy and some antidepressant compounds.

Acute and adaptive cardiovascular and metabolic effects of passive heat therapy or high-intensity interval training in patients with severe lower-limb osteoarthritis.

Exercise is painful and difficult to perform for patients with severe lower-limb osteoarthritis; consequently, reduced physical activity contributes to increased cardiometabolic disease risk. The aim of this study was to characterize the acute and adaptive cardiovascular and metabolic effects of two low or no impact therapies in patients with severe lower-limb osteoarthritis: passive heat therapy (Heat) and high-intensity interval training (HIIT) utilizing primarily the unaffected limbs, compared to a control intervention of home-based exercise (Home). Participants completed up to 12 weeks of either Heat (20-30 min immersed in 40°C water followed by ~15-min light resistance exercise), HIIT (6-8 × 60-s intervals on a cross-trainer or arm ergometer at ~90-100% peak V ̇ $$ \dot{V} $$ O2 ) or Home (~15-min light resistance exercise); all 3 sessions/week. Reductions in systolic (12 & 10 mm Hg), diastolic (7 & 4 mm Hg), and mean arterial (8 & 6 mm Hg) blood pressure (BP) were observed following one bout of Heat or HIIT exposure, lasting for the duration of the 20-min monitoring period. Across the interventions (i.e., 12 weeks), resting systolic BP and diastolic BP decreased with Heat (-9 & -4 mm Hg; p < 0.001) and HIIT (-7 & -3 mm Hg; p ≤ 0.011), but not Home (0 & 0 mm Hg; p ≥ 0.785). The systolic and diastolic BP responses to an acute exposure of Heat or HIIT in the first intervention session were moderately correlated with adaptive responses across the intervention (r ≥ 0.54, p ≤ 0.005). Neither intervention improved indices of glycemic control (p = 0.310). In summary, both Heat and HIIT induced potent immediate and adaptive hypotensive effects, and the acute response was moderately predictive of the long-term response.

Childhood Social Isolation as a Predictor of Retinal Neuronal Thickness in Middle Age: A Lifecourse Birth Cohort Study.

OBJECTIVE: We investigated whether childhood social isolation was associated with retinal neural layer changes in adulthood, and whether this association was independent of other childhood or adulthood risk factors, including adult social isolation. METHODS: Participants were members of the Dunedin Multidisciplinary Health and Development Study, a longitudinal population-based birth cohort from Aotearoa New Zealand ( n = 1037), born 1972 to 1973 and followed until age 45 years, with 94% of the living cohort still participating. Social isolation was recorded prospectively at ages 5, 7, 9, and 11 years, from teacher and parent report. Retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer thicknesses were measured via optical coherence tomography at age 45 years. RESULTS: Childhood social isolation was associated with thinner average RNFL ( B = -0.739, p = .02), nasal RNFL ( B = -1.118, p = .005), and inferior RNFL ( B = -1.524, p = .007), although only nasal RNFL remained significant after adjustment. These associations were not fully explained by other psychosocial or physical health risk factors in childhood or adulthood, nor were they mediated by adult loneliness or social support. CONCLUSIONS: Childhood social isolation was an independent predictor of RNFL thickness in middle age. Highlighting prospective links between childhood psychosocial adversity and retinal neuronal measures will help to inform future research into the utility of retinal neuronal thickness as a biomarker for neurodegeneration.

Therapeutic knockdown of miR-320 improves deteriorated cardiac function in a pre-clinical model of non-ischemic diabetic heart disease.

Non-ischemic diabetic heart disease (NiDHD) is characterized by diastolic dysfunction and decreased or preserved systolic function, eventually resulting in heart failure. Accelerated apoptotic cell death because of alteration of molecular signaling pathways due to dysregulation in microRNAs (miRNAs) plays a significant role in the development of NiDHD. Here, we aimed to determine the pathological role of cardiomyocyte-enriched pro-apoptotic miR-320 in the development of NiDHD. We identified a marked upregulation of miR-320 that was associated with downregulation of its target protein insulin growth factor-1 (IGF-1) in human right atrial appendage tissue in the late stages of cardiomyopathy in type 2 diabetic db/db mice and high-glucose-cultured human ventricular cardiomyocytes (AC-16 cells). In vitro knockdown of miR-320 in high-glucose-exposed AC-16 cells using locked nucleic acid (LNA) anti-miR-320 markedly reduced high-glucose-induced apoptosis by restoring IGF-1 and Bcl-2. Finally, in vivo knockdown of miR-320 in 24-week-old type 2 diabetic db/db mice reduced cardiomyocyte apoptosis and interstitial fibrosis while restoring vascular density. This resulted in partial recovery of the impaired diastolic and systolic function. Our study provides evidence that miR-320 is a late-responding miRNA that aggravates apoptosis and cardiac dysfunction in the diabetic heart, and that therapeutic knockdown of miR-320 is beneficial in partially restoring the deteriorated cardiac function.

Survival in Patients With Suspected Myocardial Infarction With Nonobstructive Coronary Arteries: A Comprehensive Systematic Review and Meta-Analysis From the MINOCA Global Collaboration.

BACKGROUND: Suspected myocardial infarction (MI) with nonobstructive coronary arteries (MINOCA) occurs in ≈5% to 10% of patients with MI referred for coronary angiography. The prognosis of these patients may differ to those with MI and obstructive coronary artery disease (MI-CAD) and those without a MI (patients without known history of MI [No-MI]). The primary objective of this study is to evaluate the 12-month all-cause mortality of patients with MINOCA. METHODS: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, the terms "MI," "nonobstructive," "angiography," and "prognosis" were searched in PubMed and Embase databases from inception to December 2018, including original, English language MINOCA studies with >100 consecutive patients. Publications with a heterogeneous cohort, unreported coronary stenosis, or exclusively focusing on MINOCA-mimicking conditions, were excluded. Unpublished data were obtained from the MINOCA Global Collaboration. Data were pooled and analyzed using Paule-Mandel, Hartung, Knapp, Sidik & Jonkman, or restricted maximum-likelihood random-effects meta-analysis methodology. Heterogeneity was assessed using Cochran's Q and I2 statistics. The primary outcome was 12-month all-cause mortality in patients with MINOCA, with secondary comparisons to MI-CAD and No-MI. RESULTS: The 23 eligible studies yielded 55 369 suspected MINOCA, 485 382 MI-CAD, and 33 074 No-MI. Pooled meta-analysis of 14 MINOCA studies accounting for 30 733 patients revealed an unadjusted 12-month all-cause mortality rate of 3.4% (95% CI, 2.6%-4.2%) and reinfarction (n=27 605; 10 studies) in 2.6% (95% CI, 1.7%-3.5%). MINOCA had a lower 12-month all-cause mortality than those with MI-CAD (3.3% [95% CI, 2.5%-4.1%] versus 5.6% [95% CI, 4.1%-7.0%]; odds ratio, 0.60 [95% CI, 0.52-0.70], P<0.001). In contrast, there was a statistically nonsignificant trend towards increased 12-month all-cause mortality in patients with MINOCA (2.6% [95% CI, 0%-5.9%]) compared with No-MI (0.7% [95% CI, 0.1%-1.3%]; odds ratio, 3.71 [95% CI, 0.58-23.61], P=0.09). CONCLUSIONS: In the largest contemporary MINOCA meta-analysis to date, patients with suspected MINOCA had a favorable prognosis compared with MI-CAD, but statistically nonsignificant trend toward worse outcomes compared to those with No-MI. Registration: URL: https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42020145356.

Thiamine increases resident endoglin positive cardiac progenitor cells and atrial contractile force in humans: A randomised controlled trial.

BACKGROUND: The heart has an intrinsic ability to regenerate, orchestrated by progenitor or stem cells. However, the relative complexity of non-resident cardiac progenitor cell (CPC) therapy makes modulation of resident CPCs a more attractive treatment target. Thiamine analogues improve resident CPC function in pre-clinical models. In this double blinded randomised controlled trial (identifier: ACTRN12614000755639), we examined whether thiamine would improve CPC function in humans. METHODS AND RESULTS: High dose oral thiamine (one gram twice daily) or matching placebo was administered 3-5 days prior to coronary artery bypass surgery (CABG). Right atrial appendages were collected at the time of CABG, and CPCs isolated. There was no difference in the primary outcome (proliferation ability of CPCs) between treatment groups. Older age was not associated with decreased proliferation ability. In exploratory analyses, isolated CPCs in the thiamine group showed an increase in the proportion of CD34-/CD105+ (endoglin) cells, but no difference in CD34-/CD90+ or CD34+ cells. Thiamine increased maximum force developed by isolated trabeculae, with no difference in relaxation time or beta-adrenergic responsiveness. CONCLUSION: Thiamine does not improve proliferation ability of CPC in patients undergoing CABG, but increases the proportion of CD34-/CD105+ cells. Having not met its primary endpoint, this study provides the impetus to re-examine CPC biology prior to any clinical outcome-based trial examining potential beneficial cardiovascular effects of thiamine.

Long-chain acylcarnitine 18:1 acutely increases human atrial myocardial contractility and arrhythmia susceptibility.

Long-chain acylcarnitines (LCACs) are known to directly alter cardiac contractility and electrophysiology. However, the acute effect of LCACs on human cardiac function is unknown. We aimed to determine the effect of LCAC 18:1, which has been associated with cardiovascular disease, on the contractility and arrhythmia susceptibility of human atrial myocardium. Additionally, we aimed to assess how LCAC 18:1 alters Ca2+ influx and spontaneous Ca2+ release in vitro. Human right atrial trabeculae (n = 32) stimulated at 1 Hz were treated with LCAC 18:1 at a range of concentrations (1-25 µM) for a 45-min period. Exposure to the LCAC induced a dose-dependent positive inotropic effect on myocardial contractility (maximal 1.5-fold increase vs. control). At the 25 µM dose (n = 8), this was paralleled by an enhanced propensity for spontaneous contractions (50% increase). Furthermore, all LCAC 18:1 effects on myocardial function were reversed following LCAC 18:1 washout. In fluo-4-AM-loaded HEK293 cells, LCAC 18:1 dose dependently increased cytosolic Ca2+ influx relative to vehicle controls and the short-chain acylcarnitine C3. In HEK293 cells expressing ryanodine receptor (RyR2), this increased Ca2+ influx was linked to an increased propensity for RyR2-mediated spontaneous Ca2+ release events. Our study is the first to show that LCAC 18:1 directly and acutely alters human myocardial function and in vitro Ca2+ handling. The metabolite promotes proarrhythmic muscle contractions and increases contractility. The exploratory findings in vitro suggest that LCAC 18:1 increases proarrhythmic RyR2-mediated spontaneous Ca2+ release propensity. The direct effects of metabolites on human myocardial function are essential to understand cardiometabolic dysfunction.NEW & NOTEWORTHY For the first time, the fatty acid metabolite, long-chain acylcarnitine 18:1, is shown to acutely increase the arrhythmia susceptibility and contractility of human atrial myocardium. In vitro, this was linked to an influx of Ca2+ and an enhanced propensity for spontaneous RyR2-mediated Ca2+ release.

Obesity and All Cause Mortality Following Acute Coronary Syndrome (ANZACS-QI 53).

BACKGROUND: Some studies have suggested a lower mortality in obese subjects with cardiovascular disease. The aim of this study was to evaluate the relationship between body mass index (BMI) and outcomes in patients with acute coronary syndrome (ACS). METHODS: The study included 13,742 patients undergoing coronary angiography for ACS between 2012 and 2016 from the All New Zealand Acute Coronary Syndrome-Quality Improvement (ANZACS-QI) registry. Patients were categorised by BMI (kg/m2) as: underweight <18.5, normal 18.5 to <25, overweight 25 to <30, mildly obese 30 to <35, moderately obese 35 to <40, and severely obese ≥40. The primary endpoint of the study was all cause mortality with secondary endpoints of cardiovascular disease (CVD) and non-CVD mortality within 4 years of discharge. RESULTS: Unadjusted all cause mortality was lowest in the mildly obese but no different to normal or overweight after adjustment for multiple confounders. Adjusted all cause mortality was higher in the moderately (hazard ratio [HR] 1.39, 95% CI: 1.10-1.75) and severely obese (2.06, 95% CI: 1.57-2.70) compared to the mildly obese. Non-CVD mortality (HR 1.58, 95% CI: 1.12-2.23) was the major contributor to higher all cause mortality in moderately obese patients. Both CVD mortality (HR 2.36, 95% CI: 1.67-3.32) and non-CVD mortality (HR 1.67, 95% CI: 1.07-2.61) contributed to higher all cause mortality in the severely obese. CONCLUSIONS: Moderate and severe obesity is associated with worse survival post ACS influenced by higher non-CVD mortality in moderate/severe obesity and higher CVD mortality in severe obesity.

Diabetes induces dysregulation of microRNAs associated with survival, proliferation and self-renewal in cardiac progenitor cells.

AIMS/HYPOTHESIS: Diabetes mellitus causes a progressive loss of functional efficacy in stem cells, including cardiac progenitor cells (CPCs). The underlying molecular mechanism is still not known. MicroRNAs (miRNAs) are small, non-coding RNA molecules that regulate genes at the post-transcriptional level. We aimed to determine if diabetes mellitus induces dysregulation of miRNAs in CPCs and to test if in vitro therapeutic modulation of miRNAs would improve the functions of diabetic CPCs. METHODS: CPCs were isolated from a mouse model of type 2 diabetes (db/db), non-diabetic mice and human right atrial appendage heart tissue. Total RNA isolated from mouse CPCs was miRNA profiled using Nanostring analysis. Bioinformatic analysis was employed to predict the functional effects of altered miRNAs. MS analysis was applied to determine the targets, which were confirmed by western blot analysis. Finally, to assess the beneficial effects of therapeutic modulation of miRNAs in vitro and in vivo, prosurvival miR-30c-5p was overexpressed in mouse and human diabetic CPCs, and the functional consequences were determined by measuring the level of apoptotic cell death, cardiac function and mitochondrial membrane potential (MMP). RESULTS: Among 599 miRNAs analysed in mouse CPCs via Nanostring analysis, 16 miRNAs showed significant dysregulation in the diabetic CPCs. Using bioinformatics tools and quantitative real-time PCR (qPCR) validation, four altered miRNAs (miR-30c-5p, miR-329-3p, miR-376c-3p and miR-495-3p) were identified to play an important role in cell proliferation and survival. Diabetes mellitus significantly downregulated miR-30c-5p, while it upregulated miR-329-3p, miR-376c-3p and miR-495-3p. MS analysis revealed proapoptotic voltage-dependent anion-selective channel 1 (VDAC1) as a direct target for miR-30c-5p, and cell cycle regulator, cyclin-dependent protein kinase 6 (CDK6), as the direct target for miR-329-3p, miR-376c-3p and miR-495-3p. Western blot analyses showed a marked increase in VDAC1 expression, while CDK6 expression was downregulated in diabetic CPCs. Finally, in vitro and in vivo overexpression of miR-30c-5p markedly reduced the apoptotic cell death and preserved MMP in diabetic CPCs via inhibition of VDAC1. CONCLUSIONS/INTERPRETATION: Our results demonstrate that diabetes mellitus induces a marked dysregulation of miRNAs associated with stem cell survival, proliferation and differentiation, and that therapeutic overexpression of prosurvival miR-30c-5p reduced diabetes-induced cell death and loss of MMP in CPCs via the newly identified target for miR-30c-5p, VDAC1.

Activation of the cardiac non-neuronal cholinergic system prevents the development of diabetes-associated cardiovascular complications.

BACKGROUND: Acetylcholine (ACh) plays a crucial role in the function of the heart. Recent evidence suggests that cardiomyocytes possess a non-neuronal cholinergic system (NNCS) that comprises of choline acetyltransferase (ChAT), choline transporter 1 (CHT1), vesicular acetylcholine transporter (VAChT), acetylcholinesterase (AChE) and type-2 muscarinic ACh receptors (M2AChR) to synthesize, release, degrade ACh as well as for ACh to transduce a signal. NNCS is linked to cardiac cell survival, angiogenesis and glucose metabolism. Impairment of these functions are hallmarks of diabetic heart disease (DHD). The role of the NNCS in DHD is unknown. The aim of this study was to examine the effect of diabetes on cardiac NNCS and determine if activation of cardiac NNCS is beneficial to the diabetic heart. METHODS: Ventricular samples from type-2 diabetic humans and db/db mice were used to measure the expression pattern of NNCS components (ChAT, CHT1, VAChT, AChE and M2AChR) and glucose transporter-4 (GLUT-4) by western blot analysis. To determine the function of the cardiac NNCS in the diabetic heart, a db/db mouse model with cardiac-specific overexpression of ChAT gene was generated (db/db-ChAT-tg). Animals were followed up serially and samples collected at different time points for molecular and histological analysis of cardiac NNCS components and prosurvival and proangiogenic signaling pathways. RESULTS: Immunoblot analysis revealed alterations in the components of cardiac NNCS and GLUT-4 in the type-2 diabetic human and db/db mouse hearts. Interestingly, the dysregulation of cardiac NNCS was followed by the downregulation of GLUT-4 in the db/db mouse heart. Db/db-ChAT-tg mice exhibited preserved cardiac and vascular function in comparison to db/db mice. The improved function was associated with increased cardiac ACh and glucose content, sustained angiogenesis and reduced fibrosis. These beneficial effects were associated with upregulation of the PI3K/Akt/HIF1α signaling pathway, and increased expression of its downstream targets-GLUT-4 and VEGF-A. CONCLUSION: We provide the first evidence for dysregulation of the cardiac NNCS in DHD. Increased cardiac ACh is beneficial and a potential new therapeutic strategy to prevent or delay the development of DHD.

Both Small and Large Infrarenal Aortic Size is Associated with an Increased Prevalence of Ischaemic Heart Disease.

OBJECTIVE: Past studies have suggested a potential "J shaped" relationship between infrarenal aortic diameter and both cardiovascular disease (CVD) prevalence and all cause mortality. However, screening programmes have focused primarily on large (aneurysmal) aortas. In addition, aortic diameter is rarely adjusted for body size, which is particularly important for women. This study aimed to investigate specifically the relationship between body size adjusted infrarenal aortic diameter and baseline prevalence of CVD. METHODS: A retrospective analysis was performed on a total of 4882 elderly (>50 years) participants (mean age 69.4 ± 8.9 years) for whom duplex ultrasound to assess infrarenal abdominal aortic diameters had been performed. History of CVDs, including ischaemic heart disease (IHD), and associated risk factors were collected at the time of assessment. A derivation cohort of 1668 participants was used to select cut offs at the lower and upper 12.5% tails of the aortic size distributions (aortic size index of <0.84 and >1.2, respectively), which was then tested in a separate cohort. RESULTS: A significantly elevated prevalence of CVD, and specifically IHD, was observed in participants with both small and large aortas. These associations remained significant following adjustment for age, sex, diabetes, hypertension, dyslipidaemia, obesity (body mass index), and smoking. CONCLUSION: The largest and smallest infrarenal aortic sizes were both associated with prevalence of IHD. In addition to identifying those with aneurysmal disease, it is hypothesised that screening programmes examining infrarenal aortic size may also have the potential to improve global CVD risk prediction by identifying those with small aortas.

Inotropic and lusitropic, but not arrhythmogenic, effects of adipocytokine resistin on human atrial myocardium.

The adipocytokine resistin is released from epicardial adipose tissue (EAT). Plasma resistin and EAT deposition are independently associated with atrial fibrillation. The EAT secretome enhances arrhythmia susceptibility and inotropy of human myocardium. Therefore, we aimed to determine the effect of resistin on the function of human myocardium and how resistin contributes to the proarrhythmic effect of EAT. EAT biopsies were obtained from 25 cardiac surgery patients. Resistin levels were measured by ELISA in 24-h EAT culture media (n = 8). The secretome resistin concentrations increased over the culture period to a maximal level of 5.9 ± 1.2 ng/mL. Coculture with ß-adrenergic agonists isoproterenol (n = 4) and BRL37344 (n = 13) had no effect on EAT resistin release. Addition of resistin (7, 12, 20 ng/mL) did not significantly increase the spontaneous contraction propensity of human atrial trabeculae (n = 10) when given alone or in combination with isoproterenol. Resistin dose-dependently increased trabecula-developed force (maximal 2.9-fold increase, P < 0.0001), as well as the maximal rates of contraction (2.6-fold increase, P = 0.002) and relaxation (1.8-fold increase, P = 0.007). Additionally, the postrest potentiation capacity of human trabeculae was reduced at all resistin doses, suggesting that the inotropic effect induced by resistin might be due to altered sarcoplasmic reticulum Ca2+ handling. EAT resistin release is not modulated by common arrhythmia triggers. Furthermore, exogenous resistin does not promote arrhythmic behavior in human atrial trabeculae. Resistin does, however, induce an acute dose-dependent positive inotropic and lusitropic effect.

Upregulation of microRNA-532 enhances cardiomyocyte apoptosis in the diabetic heart.

Type 2 diabetes has a strong association with the development of cardiovascular disease, which is grouped as diabetic heart disease (DHD). DHD is associated with the progressive loss of cardiovascular cells through the alteration of molecular signalling pathways associated with cell death. In this study, we sought to determine whether diabetes induces dysregulation of miR-532 and if this is associated with accentuated apoptosis. RT-PCR analysis showed a significant increase in miR-532 expression in the right atrial appendage tissue of type 2 diabetic patients undergoing coronary artery bypass graft surgery. This was associated with marked downregulation of its anti-apoptotic target protein apoptosis repressor with caspase recruitment domain (ARC) and increased TUNEL positive cardiomyocytes. Further analysis showed a positive correlation between apoptosis and miR-532 levels. Time-course experiments in a mouse model of type 2 diabetes showed that diabetes-induced activation of miR-532 occurs in the later stage of the disease. Importantly, the upregulation of miR-532 preceded the activation of pro-apoptotic caspase-3/7 activity. Finally, inhibition of miR-532 activity in high glucose cultured human cardiomyocytes prevented the downregulation of ARC and attenuated apoptotic cell death. Diabetes induced activation of miR-532 plays a critical role in accelerating cardiomyocytes apoptosis. Therefore, miR-532 may serve as a promising therapeutic agent to overcome the diabetes-induced loss of cardiomyocytes.

DNA methylation profiling identifies a high effect genetic variant for lipoprotein(a) levels.

Changes in whole blood DNA methylation levels at several CpG sites have been associated with circulating blood lipids, specifically high-density lipoprotein and triglycerides. This study performs a discovery and validation epigenome-wide association study (EWAS) for circulating lipoprotein(a) [Lp(a)], an independent risk factor for cardiovascular diseases. Whole-blood DNA methylation profiles were assessed in a cohort of 1020 elderly individuals using the Illumina EPIC array and independent validation in 359 elderly males using the Illumina 450 k array. Plasma Lp(a) was measured using an apolipoprotein(a)-size-independent ELISA. Epigenome-wide rank regression analysis identified and validated a single CpG site, cg17028067 located in intron 1 of the LPA gene, that was significantly associated with plasma Lp(a) levels after correction for multiple testing. Genotyping of the site identified a relatively uncommon SNP (rs76735376, MAF <0.02) at the CpG site that largely explained the observed methylation effect. Rs76735376 is an expression quantitative trait loci for the LPA gene and could affect expression by altering enhancer activity. This EWAS for plasma Lp(a) identified a single CpG site within LPA. This association is due to an uncommon, but highly effective genetic variant, which was not in significant linkage disequilibrium with other variants known to influence Lp(a) levels or apo(a) isoform size. This study highlights the utility of CpG site methylation to identify potentially important genetic associations that would not be readily apparent in a comparable size genetic association study.

Frailty in Elderly Patients Undergoing Cardiac Surgery Increases Hospital Stay and 12-Month Readmission Rate.

BACKGROUND: Cardiac surgery risk scoring systems predict operative mortality but not outcomes related to preoperative frailty. The aim of this study was to assess frailty in a cohort of older cardiac surgery patients as a predictor of postoperative outcomes. METHODS: Prospective data was collected on patients 65 years of age and older undergoing cardiac surgery between September 2015 and October 2016 at Dunedin Hospital. Frailty was assessed with the Edmonton frail scale and five-metre gait speed. The primary endpoint was length of hospital stay. Secondary outcomes included postoperative complications, major adverse events, death and 12-month readmission rate. RESULTS: Among the 96 patients, median age was 74 (interquartile range 10.5) and 65 (68%) were males. Of the sample 64 (67%) were scored as not frail, 22 (23%) as vulnerable, and 10 (10%) as frail. The median (interquartile range) postoperative days' stay were: not frail 6 (2), vulnerable 9.5 (8), and frail 15 (13). Survival analysis adjusting for EuroSCORE II, age, sex and surgery type showed that greater Edmonton Frail Scale scores were independently predictive of longer post-surgery hospital stay with a hazard ratio for discharge of 0.83 (95% confidence interval 0.76-0.91, p<0.001) per point. The Edmonton Frail Scale score was associated with the 12-month post discharge number of readmissions (adjusted incidence rate ratio 1.24 (95% confidence interval 1.13-1.37, p<0.001) per point. CONCLUSIONS: The Edmonton Frail Scale score predicts length of hospital stay post cardiac surgery and 12-month readmission rate in patients older than 65 years of age.

Acute interaction between human epicardial adipose tissue and human atrial myocardium induces arrhythmic susceptibility.

Epicardial adipose tissue (EAT) deposition has a strong clinical association with atrial arrhythmias; however, whether a direct functional interaction exists between EAT and the myocardium to induce atrial arrhythmias is unknown. Therefore, we aimed to determine whether human EAT can be an acute trigger for arrhythmias in human atrial myocardium. Human trabeculae were obtained from right atrial appendages of patients who have had cardiac surgery (n = 89). The propensity of spontaneous contractions (SCs) in the trabeculae (proxy for arrhythmias) was determined under physiological conditions and during known triggers of SCs (high Ca2+, ß-adrenergic stimulation). To determine whether EAT could trigger SCs, trabeculae were exposed to superfusate of fresh human EAT, and medium of 24 h-cultured human EAT treated with ß1/2 (isoproterenol) or ß3 (BRL37344) adrenergic agonists. Without exposure to EAT, high Ca2+ and ß1/2-adrenergic stimulation acutely triggered SCs in, respectively, 47% and 55% of the trabeculae that previously were not spontaneously active. Acute ß3-adrenergic stimulation did not trigger SCs. Exposure of trabeculae to either superfusate of fresh human EAT or untreated medium of 24 h-cultured human EAT did not induce SCs; however, specific ß3-adrenergic stimulation of EAT did trigger SCs in the trabeculae, either when applied to fresh (31%) or cultured (50%) EAT. Additionally, fresh EAT increased trabecular contraction and relaxation, whereas media of cultured EAT only increased function when treated with the ß3-adrenergic agonist. An acute functional interaction between human EAT and human atrial myocardium exists that increases the propensity for atrial arrhythmias, which depends on ß3-adrenergic rather than ß1/2-adrenergic stimulation of EAT.

Associations between lung and endothelial function in early middle age.

BACKGROUND AND OBJECTIVE: Chronic lung disease is associated with impaired endothelial function and this may be a risk factor for poor cardiovascular health. It is unknown if there is an association between lung and endothelial function in the general population. We investigated associations between lung and endothelial function in a population-based cohort of 38-year-old men and women. METHODS: Systemic endothelial function was measured using peripheral arterial tonometry to calculate the Framingham reactive hyperaemia index. Lung function was assessed using spirometry, plethysmographic lung volumes, airway conductance and gas transfer. Associations between lung and endothelial function were assessed with and without adjustment for potential confounding factors using regression analyses. RESULTS: Sex modified the association between lung and endothelial function. Among women, lower values of pre- and post-bronchodilator spirometry, total lung capacity and functional residual capacity (FRC) were associated with worse endothelial function (P < 0.05). These associations persisted after adjustment for smoking, asthma diagnoses, fitness and body mass index. Associations were weaker among men: only FRC, airway conductance and post-bronchodilator forced expiratory volume in 1 s (FEV1 )/forced vital capacity (FVC) ratios were associated with endothelial function. Endothelial function was not associated with gas transfer in either sex. CONCLUSION: Lower lung volumes and airflow obstruction are associated with endothelial dysfunction among women. There is weaker evidence for an association between airway and endothelial function in men. These findings may partly explain the increased risk of cardiovascular disease among people with poor lung function, but suggest that there are sex differences in this association.