Inorganic nitrate benefits contrast-induced nephropathy after coronary angiography for acute coronary syndromes: the NITRATE-CIN trial.

BACKGROUND AND AIMS: Contrast-induced nephropathy (CIN), also known as contrast-associated acute kidney injury (CA-AKI) underlies a significant proportion of the morbidity and mortality following coronary angiographic procedures in high-risk patients and remains a significant unmet need. In pre-clinical studies inorganic nitrate, which is chemically reduced in vivo to nitric oxide, is renoprotective but this observation is yet to be translated clinically. In this study, the efficacy of inorganic nitrate in the prevention of CIN in high-risk patients presenting with acute coronary syndromes (ACS) is reported. METHODS: NITRATE-CIN is a double-blind, randomized, single-centre, placebo-controlled trial assessing efficacy of inorganic nitrate in CIN prevention in at-risk patients presenting with ACS. Patients were randomized 1:1 to once daily potassium nitrate (12 mmol) or placebo (potassium chloride) capsules for 5 days. The primary endpoint was CIN (KDIGO criteria). Secondary outcomes included kidney function [estimated glomerular filtration rate (eGFR)] at 3 months, rates of procedural myocardial infarction, and major adverse cardiac events (MACE) at 12 months. This study is registered with ClinicalTrials.gov: NCT03627130. RESULTS: Over 3 years, 640 patients were randomized with a median follow-up of 1.0 years, 319 received inorganic nitrate with 321 received placebo. The mean age of trial participants was 71.0 years, with 73.3% male and 75.2% Caucasian; 45.9% had diabetes, 56.0% had chronic kidney disease (eGFR <60 mL/min) and the mean Mehran score of the population was 10. Inorganic nitrate treatment significantly reduced CIN rates (9.1%) vs. placebo (30.5%, P < .001). This difference persisted after adjustment for baseline creatinine and diabetes status (odds ratio 0.21, 95% confidence interval 0.13-0.34). Secondary outcomes were improved with inorganic nitrate, with lower rates of procedural myocardial infarction (2.7% vs. 12.5%, P = .003), improved 3-month renal function (between-group change in eGFR 5.17, 95% CI 2.94-7.39) and reduced 1-year MACE (9.1% vs. 18.1%, P = .001) vs. placebo. CONCLUSIONS: In patients at risk of renal injury undergoing coronary angiography for ACS, a short (5 day) course of once-daily inorganic nitrate reduced CIN, improved kidney outcomes at 3 months, and MACE events at 1 year compared to placebo.

Computed Tomography Cardiac Angiography Before Invasive Coronary Angiography in Patients With Previous Bypass Surgery: The BYPASS-CTCA Trial.

BACKGROUND: Patients with previous coronary artery bypass grafting often require invasive coronary angiography (ICA). However, for these patients, the procedure is technically more challenging and has a higher risk of complications. Observational studies suggest that computed tomography cardiac angiography (CTCA) may facilitate ICA in this group, but this has not been tested in a randomized controlled trial. METHODS: This study was a single-center, open-label randomized controlled trial assessing the benefit of adjunctive CTCA in patients with previous coronary artery bypass grafting referred for ICA. Patients were randomized 1:1 to undergo CTCA before ICA or ICA alone. The co-primary end points were procedural duration of the ICA (defined as the interval between local anesthesia administration for obtaining vascular access and removal of the last catheter), patient satisfaction after ICA using a validated questionnaire, and the incidence of contrast-induced nephropathy. Linear regression was used for procedural duration and patient satisfaction score; contrast-induced nephropathy was analyzed using logistic regression. We applied the Bonferroni correction, with P<0.017 considered significant and 98.33% CIs presented. Secondary end points included incidence of procedural complications and 1-year major adverse cardiac events. RESULTS: Over 3 years, 688 patients were randomized with a median follow-up of 1.0 years. The mean age was 69.8±10.4 years, 108 (15.7%) were women, 402 (58.4%) were White, and there was a high burden of comorbidity (85.3% hypertension and 53.8% diabetes). The median time from coronary artery bypass grafting to angiography was 12.0 years, and there were a median of 3 (interquartile range, 2 to 3) grafts per participant. Procedure duration of the ICA was significantly shorter in the CTCA+ICA group (CTCA+ICA, 18.6±9.5 minutes versus ICA alone, 39.5±16.9 minutes [98.33% CI, -23.5 to -18.4]; P<0.001), alongside improved mean ICA satisfaction scores (1=very good to 5=very poor; -1.1 difference [98.33% CI, -1.2 to -0.9]; P<0.001), and reduced incidence of contrast-induced nephropathy (3.4% versus 27.9%; odds ratio, 0.09 [98.33% CI, 0.04-0.2]; P<0.001). Procedural complications (2.3% versus 10.8%; odds ratio, 0.2 [95% CI, 0.1-0.4]; P<0.001) and 1-year major adverse cardiac events (16.0% versus 29.4%; hazard ratio, 0.4 [95% CI, 0.3-0.6]; P<0.001) were also lower in the CTCA+ICA group. CONCLUSIONS: For patients with previous coronary artery bypass grafting, CTCA before ICA leads to reductions in procedure time and contrast-induced nephropathy, with improved patient satisfaction. CTCA before ICA should be considered in this group of patients. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03736018.

Sex Differences in the Inflammatory Response: Pharmacological Opportunities for Therapeutics for Coronary Artery Disease.

Coordinated molecular responses are key to effective initiation and resolution of both acute and chronic inflammation. Vascular inflammation plays an important role in initiating and perpetuating atherosclerotic disease, specifically at the site of plaque and subsequent fibrous cap rupture. Both men and women succumb to this disease process, and although management strategies have focused on revascularization and pharmacological therapies in the acute situation to reverse vessel closure and prevent thrombogenesis, data now suggest that regulation of host inflammation may improve both morbidity and mortality, thus supporting the notion that prevention is better than cure. There is a clear sex difference in the incidence of vascular disease, and data confirm biological differences in inflammatory initiation and resolution between men and women. This article reviews contemporary opinions describing the sex difference in the initiation and resolution of inflammatory responses, with a view to explore potential targets for pharmacological intervention.

Inhaled nitric oxide suppresses neuroinflammation in experimental ischemic stroke.

Ischemic stroke is a major global health issue and characterized by acute vascular dysfunction and subsequent neuroinflammation. However, the relationship between these processes remains elusive. In the current study, we investigated whether alleviating vascular dysfunction by restoring vascular nitric oxide (NO) reduces post-stroke inflammation. Mice were subjected to experimental stroke and received inhaled NO (iNO; 50 ppm) after reperfusion. iNO normalized vascular cyclic guanosine monophosphate (cGMP) levels, reduced the elevated expression of intercellular adhesion molecule-1 (ICAM-1), and returned leukocyte adhesion to baseline levels. Reduction of vascular pathology significantly reduced the inflammatory cytokines interleukin-1ß (Il-1ß), interleukin-6 (Il-6), and tumor necrosis factor-α (TNF-α), within the brain parenchyma. These findings suggest that vascular dysfunction is responsible for leukocyte adhesion and that these processes drive parenchymal inflammation. Reversing vascular dysfunction may therefore emerge as a novel approach to diminish neuroinflammation after ischemic stroke and possibly other ischemic disorders.

The ARRIVE guidelines 2.0: Updated guidelines for reporting animal research.

Reproducible science requires transparent reporting. The ARRIVE guidelines (Animal Research: Reporting of In Vivo Experiments) were originally developed in 2010 to improve the reporting of animal research. They consist of a checklist of information to include in publications describing in vivo experiments to enable others to scrutinise the work adequately, evaluate its methodological rigour, and reproduce the methods and results. Despite considerable levels of endorsement by funders and journals over the years, adherence to the guidelines has been inconsistent, and the anticipated improvements in the quality of reporting in animal research publications have not been achieved. Here, we introduce ARRIVE 2.0. The guidelines have been updated and information reorganised to facilitate their use in practice. We used a Delphi exercise to prioritise and divide the items of the guidelines into 2 sets, the "ARRIVE Essential 10," which constitutes the minimum requirement, and the "Recommended Set," which describes the research context. This division facilitates improved reporting of animal research by supporting a stepwise approach to implementation. This helps journal editors and reviewers verify that the most important items are being reported in manuscripts. We have also developed the accompanying Explanation and Elaboration (E&E) document, which serves (1) to explain the rationale behind each item in the guidelines, (2) to clarify key concepts, and (3) to provide illustrative examples. We aim, through these changes, to help ensure that researchers, reviewers, and journal editors are better equipped to improve the rigour and transparency of the scientific process and thus reproducibility.

Reporting animal research: Explanation and elaboration for the ARRIVE guidelines 2.0.

Improving the reproducibility of biomedical research is a major challenge. Transparent and accurate reporting is vital to this process; it allows readers to assess the reliability of the findings and repeat or build upon the work of other researchers. The ARRIVE guidelines (Animal Research: Reporting In Vivo Experiments) were developed in 2010 to help authors and journals identify the minimum information necessary to report in publications describing in vivo experiments. Despite widespread endorsement by the scientific community, the impact of ARRIVE on the transparency of reporting in animal research publications has been limited. We have revised the ARRIVE guidelines to update them and facilitate their use in practice. The revised guidelines are published alongside this paper. This explanation and elaboration document was developed as part of the revision. It provides further information about each of the 21 items in ARRIVE 2.0, including the rationale and supporting evidence for their inclusion in the guidelines, elaboration of details to report, and examples of good reporting from the published literature. This document also covers advice and best practice in the design and conduct of animal studies to support researchers in improving standards from the start of the experimental design process through to publication.

Local delivery of nitric oxide prevents endothelial dysfunction in periodontitis.

AIMS: Increased cardiovascular disease risk underlies elevated rates of mortality in individuals with periodontitis. A key characteristic of those with increased cardiovascular risk is endothelial dysfunction, a phenomenon synonymous with deficiencies of bioavailable nitric oxide (NO), and prominently expressed in patients with periodontitis. Also, inorganic nitrate can be reduced to NO in vivo to restore NO levels, leading us to hypothesise that its use may be beneficial in reducing periodontitis-associated endothelial dysfunction. Herein we sought to determine whether inorganic nitrate improves endothelial function in the setting of periodontitis and if so to determine the mechanisms underpinning any responses seen. METHODS AND RESULTS: Periodontitis was induced in mice by placement of a ligature for 14 days around the second molar. Treatment in vivo with potassium nitrate, either prior to or following establishment of experimental periodontitis, attenuated endothelial dysfunction, as determined by assessment of acetylcholine-induced relaxation of aortic rings, compared to control (potassium chloride treatment). These beneficial effects were associated with a suppression of vascular wall inflammatory pathways (assessed by quantitative-PCR), increases in the anti-inflammatory cytokine interleukin (IL)-10 and reduced tissue oxidative stress due to attenuation of xanthine oxidoreductase-dependent superoxide generation. In patients with periodontitis, plasma nitrite levels were not associated with endothelial function indicating dysfunction. CONCLUSION: Our results suggest that inorganic nitrate protects against, and can partially reverse pre-existing, periodontitis-induced endothelial dysfunction through restoration of nitrite and thus NO levels. This research highlights the potential of dietary nitrate as adjunct therapy to target the associated negative cardiovascular outcomes in patients with periodontitis.

Melatonin ameliorates aging-related impaired angiogenesis in gastric endothelial cells via local actions on mitochondria and VEGF-survivin signaling.

Tissue injury healing is impaired in aging, and this impairment is caused in part by reduced angiogenesis. Melatonin, a neuroendocrine hormone that regulates sleep and circadian rhythm, is also produced in the gastrointestinal tract. The expression of melatonin receptors MT1 and MT2 in gastric endothelial cells and their roles in aging-related impairment of gastric angiogenesis have not been examined. We hypothesized that MT1 and MT2 expression is reduced in gastric endothelial cells of aging rats and that melatonin treatment can upregulate their expression and improve angiogenesis. We examined the expression of MT1 and MT2 in gastric endothelial cells (GECs) isolated from young and aging rats. We also examined the effects of melatonin treatment on angiogenesis, GEC mitochondrial function, expression of vascular endothelial growth factor (VEGF), its signaling receptor (VEGFR-2), and the inhibitor of apoptosis protein, survivin. Young and aging GECs expressed MT1 (in the cytoplasm and mitochondria) and MT2 (in nucleus and mitochondria). In aging GECs, MT1 and MT2 levels, in vitro angiogenesis, and mitochondrial membrane potential were significantly reduced (by 1.5-fold, 1.9-fold, 3.1-fold, and 1.63-fold, respectively) compared with young GECs. Melatonin treatment of aging GECs significantly increased MT1 and MT2 expression compared with the controls, induced nuclear translocation of MT1, and significantly ameliorated the aging-related impairment of angiogenesis and mitochondrial function. Aging GECs have significantly reduced MT1 and MT2 expression, angiogenesis, and mitochondrial membrane potential compared with young GECs. Treatment of aging GECs with melatonin increases expression of VEGF receptor and survivin and ameliorates aging-related impaired angiogenesis and mitochondrial function.NEW & NOTEWORTHY This study showed reduced expression of melatonin receptors MT1 and MT2, angiogenesis, and mitochondrial function in gastric endothelial cells (GECs) isolated from aging rats. Treatment of aging GECs with melatonin increases expression of VEGF receptor and survivin and ameliorates aging-related impaired angiogenesis and mitochondrial function. These studies provide new insight into the mechanisms of the aging-related impairment of angiogenesis and delayed tissue injury healing and provide a rationale for melatonin treatment to reverse these abnormalities.

The ARRIVE guidelines 2.0: updated guidelines for reporting animal research.

Reproducible science requires transparent reporting. The ARRIVE guidelines (Animal Research: Reporting of In Vivo Experiments) were originally developed in 2010 to improve the reporting of animal research. They consist of a checklist of information to include in publications describing in vivo experiments to enable others to scrutinise the work adequately, evaluate its methodological rigour, and reproduce the methods and results. Despite considerable levels of endorsement by funders and journals over the years, adherence to the guidelines has been inconsistent, and the anticipated improvements in the quality of reporting in animal research publications have not been achieved. Here, we introduce ARRIVE 2.0. The guidelines have been updated and information reorganised to facilitate their use in practice. We used a Delphi exercise to prioritise and divide the items of the guidelines into 2 sets, the 'ARRIVE Essential 10,' which constitutes the minimum requirement, and the 'Recommended Set,' which describes the research context. This division facilitates improved reporting of animal research by supporting a stepwise approach to implementation. This helps journal editors and reviewers verify that the most important items are being reported in manuscripts. We have also developed the accompanying Explanation and Elaboration document, which serves (1) to explain the rationale behind each item in the guidelines, (2) to clarify key concepts, and (3) to provide illustrative examples. We aim, through these changes, to help ensure that researchers, reviewers, and journal editors are better equipped to improve the rigour and transparency of the scientific process and thus reproducibility.

The ARRIVE guidelines 2.0: Updated guidelines for reporting animal research.

Reproducible science requires transparent reporting. The ARRIVE guidelines (Animal Research: Reporting of In Vivo Experiments) were originally developed in 2010 to improve the reporting of animal research. They consist of a checklist of information to include in publications describing in vivo experiments to enable others to scrutinise the work adequately, evaluate its methodological rigour, and reproduce the methods and results. Despite considerable levels of endorsement by funders and journals over the years, adherence to the guidelines has been inconsistent, and the anticipated improvements in the quality of reporting in animal research publications have not been achieved. Here, we introduce ARRIVE 2.0. The guidelines have been updated and information reorganised to facilitate their use in practice. We used a Delphi exercise to prioritise and divide the items of the guidelines into 2 sets, the "ARRIVE Essential 10," which constitutes the minimum requirement, and the "Recommended Set," which describes the research context. This division facilitates improved reporting of animal research by supporting a stepwise approach to implementation. This helps journal editors and reviewers verify that the most important items are being reported in manuscripts. We have also developed the accompanying Explanation and Elaboration document, which serves (1) to explain the rationale behind each item in the guidelines, (2) to clarify key concepts, and (3) to provide illustrative examples. We aim, through these changes, to help ensure that researchers, reviewers, and journal editors are better equipped to improve the rigour and transparency of the scientific process and thus reproducibility.

The ARRIVE guidelines 2.0: Updated guidelines for reporting animal research.

Reproducible science requires transparent reporting. The ARRIVE guidelines (Animal Research: Reporting of In Vivo Experiments) were originally developed in 2010 to improve the reporting of animal research. They consist of a checklist of information to include in publications describing in vivo experiments to enable others to scrutinise the work adequately, evaluate its methodological rigour, and reproduce the methods and results. Despite considerable levels of endorsement by funders and journals over the years, adherence to the guidelines has been inconsistent, and the anticipated improvements in the quality of reporting in animal research publications have not been achieved. Here, we introduce ARRIVE 2.0. The guidelines have been updated and information reorganised to facilitate their use in practice. We used a Delphi exercise to prioritise and divide the items of the guidelines into 2 sets, the "ARRIVE Essential 10," which constitutes the minimum requirement, and the "Recommended Set," which describes the research context. This division facilitates improved reporting of animal research by supporting a stepwise approach to implementation. This helps journal editors and reviewers verify that the most important items are being reported in manuscripts. We have also developed the accompanying Explanation and Elaboration document, which serves (1) to explain the rationale behind each item in the guidelines, (2) to clarify key concepts, and (3) to provide illustrative examples. We aim, through these changes, to help ensure that researchers, reviewers, and journal editors are better equipped to improve the rigour and transparency of the scientific process and thus reproducibility.

Research priorities for rehabilitation and aging with HIV: a framework from the Canada-International HIV and Rehabilitation Research Collaborative (CIHRRC).

BACKGROUND: People living with HIV are living longer, and can experience physical, mental and social health challenges associated with aging and multimorbidity. Rehabilitation is well positioned to address disability and maximize healthy aging. An international collaborative network, called the Canada-International HIV and Rehabilitation Research Collaborative (CIHRRC), works to guide this emerging field. In this article, we report findings from CIHRRC's aim to identify emerging research priorities in HIV, aging and rehabilitation from the perspectives of people living with HIV, clinicians, researchers, representatives from community organizations and policy stakeholders. METHODS: We conducted a multi-stakeholder multi-method international consultation with people living with HIV, researchers, clinicians and representatives of community-based organizations to identify research priorities in HIV, aging and rehabilitation. Stakeholders identified research priorities during a one-day International Forum comprised of presentations and facilitated discussion. We collated and analyzed data using content analytical techniques, resulting in a framework of research priorities. RESULTS: Sixty-nine stakeholders from countries including Canada (n = 62; 90%), the United Kingdom (n = 5; 7%), United States (n = 1; 1%) and Australia (n = 1; 1%) attended the International Forum on HIV, Aging and Rehabilitation Research. Stakeholders represented community-based organizations (n = 20; 29%), academic institutions (n = 18; 26%), community or institutional healthcare organizations (n = 11; 16%), research or knowledge production organizations (n = 10; 14%), and organizations representing government or industry (n = 10; 14%). The Framework of Research Priorities in HIV, Aging and Rehabilitation includes seven research priorities: (1) nature, extent and impact of disability, concurrent health conditions and chronic inflammation with HIV; (2) prevalence, severity and impact of frailty; (3) community and social participation aging with HIV; (4) strategies for chronic disease management and healthy aging with HIV; (5) facilitators and barriers to access and engagement in, rehabilitation; (6) effectiveness of rehabilitation interventions for healthy aging with HIV; and (7) advancing development and use of patient reported outcome measures in HIV and aging. The Framework highlights methodological considerations to approach the priorities and the importance of knowledge translation and exchange to apply research knowledge into practice, programs and policy. CONCLUSIONS: These priorities offer a foundation for collaboration among international and multidisciplinary teams to advance the field of HIV, aging and rehabilitation in order to promote healthy aging with HIV.

Antiinflammatory actions of inorganic nitrate stabilize the atherosclerotic plaque.

Reduced bioavailable nitric oxide (NO) plays a key role in the enhanced leukocyte recruitment reflective of systemic inflammation thought to precede and underlie atherosclerotic plaque formation and instability. Recent evidence demonstrates that inorganic nitrate (NO3-) through sequential chemical reduction in vivo provides a source of NO that exerts beneficial effects upon the cardiovascular system, including reductions in inflammatory responses. We tested whether the antiinflammatory effects of inorganic nitrate might prove useful in ameliorating atherosclerotic disease in Apolipoprotein (Apo)E knockout (KO) mice. We show that dietary nitrate treatment, although having no effect upon total plaque area, caused a reduction in macrophage accumulation and an elevation in smooth muscle accumulation within atherosclerotic plaques of ApoE KO mice, suggesting plaque stabilization. We also show that in nitrate-fed mice there is reduced systemic leukocyte rolling and adherence, circulating neutrophil numbers, neutrophil CD11b expression, and myeloperoxidase activity compared with wild-type littermates. Moreover, we show in both the ApoE KO mice and using an acute model of inflammation that this effect upon neutrophils results in consequent reductions in inflammatory monocyte expression that is associated with elevations of the antiinflammatory cytokine interleukin (IL)-10. In summary, we demonstrate that inorganic nitrate suppresses acute and chronic inflammation by targeting neutrophil recruitment and that this effect, at least in part, results in consequent reductions in the inflammatory status of atheromatous plaque, and suggest that this effect may have clinical utility in the prophylaxis of inflammatory atherosclerotic disease.

Mitochondria in gastric epithelial cells are the key targets for NSAIDs-induced injury and NGF cytoprotection.

Gastric epithelial cells are important components of mucosal protection and targets of nonsteroidal anti-inflammatory drugs (NSAIDs)-induced injury. Diclofenac (DFN) is one of the most widely used NSAIDs; however, even its short-term use can induce gastric erosions and ulcers. Nerve growth factor (NGF) has been reported to act not only on neuronal cells but also on endothelial cells; however, its action on gastric epithelial cells is unknown. This study was aimed to determine, whether NGF can protect gastric epithelial cells against DFN-induced injury, and to determine the underlying molecular mechanisms with a focus on mitochondria, survivin, and insulin-like growth factor 1 (IGF-1). Cultured normal rat gastric mucosal epithelial cells 1 (RGM1) were treated with phosphate-buffered saline (PBS; control), NGF (100 ng/mL) and/or DFN (0.25-1.00 mM) for 4 hours. We examined: (1) cell injury by confocal microscopy; (2) cell death/survival using Calcein AM live cell tracking dye; (3) mitochondrial structure and membrane potential function using MitoTracker in live cells; and (4) expression of NGF, its receptor - tropomyosin receptor kinase A (TrkA), survivin and IGF-1 by immunostaining. DFN treatment of RGM1 cells for 4 hours caused extensive cell injury, mitochondrial disintegration, reduced cell viability (from 94 ± 3% in controls to 14 ± 4% in 0.5 mM DFN-treated cells; P < 0.001), and expression of survivin and IGF-1. NGF treatment significantly increased survivin and IGF-1 expression by 41% and 75%, respectively versus PBS controls. Pretreatment with NGF before DFN treatment reduced mitochondrial damage and cell death by 73% and 82%, respectively versus treatment with DFN alone (all P < 0.001). This study also showed the presence of high-affinity TrkA receptors in the plasma membrane and mitochondria of RGM1 cells indicating novel actions of NGF.

NSAID-induced injury of gastric epithelial cells is reversible: roles of mitochondria, AMP kinase, NGF, and PGE2.

Nonsteroidal anti-inflammatory drugs (NSAIDs) such as diclofenac (DFN) and indomethacin (INDO) are extensively used worldwide. Their main side effects are injury of the gastrointestinal tract, including erosions, ulcers, and bleeding. Since gastric epithelial cells (GEPCs) are crucial for mucosal defense and are the major target of injury, we examined the extent to which DFN- and INDO-induced GEPC injury can be reversed by nerve growth factor (NGF), 16,16 dimethyl prostaglandin E2 (dmPGE2), and 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), the pharmacological activator of the metabolic sensor AMP kinase (AMPK). Cultured normal rat gastric mucosal epithelial (RGM1) cells were treated with PBS (control), NGF, dmPGE2, AICAR, and/or NSAID (DFN or INDO) for 1-4 h. We examined cell injury by confocal microscopy, cell death/survival using calcein AM, mitochondrial membrane potential using MitoTracker, and phosphorylation of AMPK by Western blotting. DFN and INDO treatment of RGM1 cells for 2 h decreased mitochondrial membrane potential and cell viability. NGF posttreatment (initiated 1 or 2 h after DFN or INDO) reversed the dissipation of mitochondrial membrane potential and cell injury caused by DFN and INDO and increased cell viability versus cells treated for 4 h with NSAID alone. Pretreatment with dmPGE2 and AICAR significantly protected these cells from DFN- and INDO-induced injury, whereas dmPGE2 and AICAR posttreatment (initiated 1 h after NSAID treatment) reversed cell injury and significantly increased cell viability and rescued the cells from NSAID-induced mitochondrial membrane potential reduction. DFN and INDO induce extensive mitochondrial injury and GEPC death, which can be significantly reversed by NGF, dmPGE2, and AICAR.NEW & NOTEWORTHY This study demonstrated that mitochondria are key targets of diclofenac- and indomethacin-induced injury of gastric epithelial cells and that diclofenac and indomethacin injury can be prevented and, importantly, also reversed by treatment with nerve growth factor, 16,16 dimethyl prostaglandin E2, and 5-aminoimidazole-4-carboxamide ribonucleotide.

Endogenously generated arachidonate-derived ligands for TRPV1 induce cardiac protection in sepsis.

The severity of cardiac dysfunction predicts mortality in sepsis. Activation of transient receptor potential vanilloid receptor type (TRPV)-1, a predominantly neuronal nonselective cation channel, has been shown to improve outcome in sepsis and endotoxemia. However, the role of TRPV1 and the identity of its endogenous ligands in the cardiac dysfunction caused by sepsis and endotoxemia are unknown. Using TRPV1-/- and TRPV1+/+ mice, we showed that endogenous activation of cardiac TRPV1 during sepsis is key to limiting the ensuing cardiac dysfunction. Use of liquid chromatography-tandem mass spectrometry lipid analysis and selective inhibitors of arachidonic metabolism suggest that the arachidonate-derived TRPV1 activator, 20-hydroxyeicosateraenoic acid (20-HETE), underlies a substantial component of TRPV1-mediated cardioprotection in sepsis. Moreover, using selective antagonists for neuropeptide receptors, we show that this effect of TRPV1 relates to the activity of neuronally released cardiac calcitonin gene-related peptide (CGRP) and that, accordingly, administration of CGRP can rescue cardiac dysfunction in severe endotoxemia. In sum activation of TRPV1 by 20-HETE leads to the release of CGRP, which protects the heart against the cardiac dysfunction in endotoxemia and identifies both TRPV1 and CGRP receptors as potential therapeutic targets in endotoxemia.-Chen, J., Hamers, A. J. P., Finsterbusch, M., Massimo, G., Zafar, M., Corder, R., Colas, R. A., Dalli, J., Thiemermann, C., Ahluwalia, A. Endogenously generated arachidonate-derived ligands for TRPV1 induce cardiac protection in sepsis.

The GTN patch: a simple and effective new approach to cardioprotection?

There remains a significant un-met need to reduce the extent of myocardial injury caused by ischaemia and reperfusion injury in patients experiencing an ST-elevation MI. Although nitric oxide is central to many cardioprotective strategies currently undergoing investigation, cardioprotection from the delivery of nitrates/nitrites has been inconsistently observed. The route of administration appears to be a critical variable. The glyceryl trinitrate (GTN) patch is commonly used as a simple and practical means of delivering nitric oxide to patients with ischaemic heart disease, but whether acute cardioprotection can be achieved by application of a GTN patch has not been investigated before. Here, we use a mouse model to demonstrate that a GTN patch is highly cardioprotective when applied immediately prior to 40 min occlusion of the left anterior coronary artery followed by 2 h reperfusion, reducing infarct size from 54 ± 4% in control mice, to 28 ± 4% (P < 0.001, N = 7). The degree of protection was similar to that achieved with a standard remote ischaemic preconditioning protocol. Furthermore, and of greater potential clinical relevance, a GTN patch was also protective when applied well after the initiation of ischaemia and 15 min prior to reperfusion (28 ± 4 vs 59 ± 4%; P < 0.01, N = 5). Confirmatory experiments verified the expected effect increase in plasma nitrite levels and decrease in blood pressure. The simplicity and rapidity of GTN patch application (easily applied in an ambulance or cardiac catheterization laboratory), and low cost (potentially relevant to low-income countries), make it attractive for further investigation.

Randomized phase 2 trial of intracoronary nitrite during acute myocardial infarction.

RATIONALE: Preclinical evidence demonstrates that inorganic nitrite, after its in situ conversion to nitric oxide, attenuates consequent myocardial reperfusion injury. OBJECTIVE: We investigated whether intracoronary injection of nitrite during primary percutaneous coronary intervention might improve infarct size in ST-elevated myocardial infarction. METHODS AND RESULTS: Patients undergoing primary percutaneous coronary intervention (n=80) were randomized to receive intracoronary (10 mL) sodium nitrite (1.8 µmol) or NaCl (placebo) before balloon inflation. The primary end point was infarct size assessed by measuring creatine kinase release. Secondary outcomes included infarct size assessed by troponin T release and by cardiac MRI on day 2. Baseline characteristics were similar between the groups. No evidence of differences in creatine kinase release (P=0.92), troponin T (P=0.85), or cardiac MRI-assessed infarct size (P=0.254) were evident. In contrast, there was an improvement [corrected] in myocardial salvage index (P=0.05) and reduction in [corrected] major adverse cardiac event at 1 year (2.6% versus 15.8%; P=0.04) in the nitrite group. In a 66-patient subgroup with thrombolysis in myocardial infarction ≤1 flow, there was reduced serum creatine kinase (P=0.030) and a 19% reduction in cardiac MRI-determined infarct size (P=0.034) with nitrite. No adverse effects of nitrite were detected. CONCLUSIONS: In this phase II study, intracoronary nitrite infusion did not alter infarct size, although a trend to improved myocardial salvage index and a significant reduction in major adverse cardiac event was evident. In a subgroup of patients with thrombolysis in myocardial infarction flow ≤1, nitrite reduced infarct size and major adverse cardiac event and improved myocardial salvage index, indicating that a phase III clinical trial assessing intracoronary nitrite administration as an adjunct to percutaneous coronary intervention in ST-elevated myocardial infarction patients is warranted. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01584453.

Activation of the Classical Mitogen-Activated Protein Kinases Is Part of the Shiga Toxin-Induced Ribotoxic Stress Response and May Contribute to Shiga Toxin-Induced Inflammation.

Infection with enterohemorrhagic Escherichia coli (EHEC) can result in severe disease, including hemorrhagic colitis and the hemolytic uremic syndrome. Shiga toxins (Stx) are the key EHEC virulence determinant contributing to severe disease. Despite inhibiting protein synthesis, Shiga toxins paradoxically induce the expression of proinflammatory cytokines from various cell types in vitro, including intestinal epithelial cells (IECs). This effect is mediated in large part by the ribotoxic stress response (RSR). The Shiga toxin-induced RSR is known to involve the activation of the stress-activated protein kinases (SAPKs) p38 and JNK. In some cell types, Stx also can induce the classical mitogen-activated protein kinases (MAPKs) or ERK1/2, but the mechanism(s) by which this activation occurs is unknown. In this study, we investigated the mechanism by which Stx activates ERK1/2s in IECs and the contribution of ERK1/2 activation to interleukin-8 (IL-8) expression. We demonstrate that Stx1 activates ERK1/2 in a biphasic manner: the first phase occurs in response to StxB1 subunit, while the second phase requires StxA1 subunit activity. We show that the A subunit-dependent ERK1/2 activation is mediated through ZAK-dependent signaling, and inhibition of ERK1/2 activation via the MEK1/2 inhibitors U0126 and PD98059 results in decreased Stx1-mediated IL-8 mRNA. Finally, we demonstrate that ERK1/2 are activated in vivo in the colon of Stx2-intoxicated infant rabbits, a model in which Stx2 induces a primarily neutrophilic inflammatory response. Together, our data support a role for ERK1/2 activation in the development of Stx-mediated intestinal inflammation.

Nerve growth factor is critical requirement for in vitro angiogenesis in gastric endothelial cells.

Angiogenesis is critical for the healing of gastric mucosal injury and is considered to be primarily regulated by vascular endothelial growth factor (VEGF), the fundamental proangiogenic factor. The role of nerve growth factor (NGF) in gastric angiogenesis is unknown. We examined the expression of NGF and its TrkA receptor in endothelial cells (ECs) isolated from gastric mucosa of rats (GMECs), the effect of NGF treatment on in vitro angiogenesis in GMECs, and, the mechanisms underlying NGF's proangiogenic actions. Isolated GMECs from Fisher rats were treated with vehicle, NGF (10-1,000 ng/ml), VEGF (20 ng/ml), or NGF+VEGF. To determine whether and to what extent NGF is critical for angiogenesis in GMECs, we silenced NGF expression using specific siRNA and examined in vitro angiogenesis with and without treatment with exogenous NGF and/or VEGF. Treatment of GMECs with NGF significantly increased in vitro angiogenesis similar to that seen in GMECs treated with VEGF. Silencing of NGF in GMECs abolished angiogenesis, and this effect was reversed only by exogenous NGF but not VEGF, which indicates a direct proangiogenic action of NGF on GMECs that is, at least in part, distinct and independent of VEGF. NGF's proangiogenic action on GMECs was mediated via PI3-K/Akt signaling. This study showed for the first time that gastric mucosal ECs express NGF and its receptor TrkA and that NGF is critical for angiogenesis in these cells.