The Dual Role of Oxidative Stress in Atherosclerosis and Coronary Artery Disease: Pathological Mechanisms and Diagnostic Potential

Oxidative stress plays a pivotal role in the pathogenesis of atherosclerosis and coronary artery disease (CAD), with both beneficial and detrimental effects on cardiovascular health. On one hand, the excessive production of reactive oxygen species (ROS) contributes to endothelial dysfunction, inflammation, and vascular remodeling, which are central to the development and progression of CAD. These pathological effects drive key processes such as atherosclerosis, plaque formation, and thrombosis. On the other hand, moderate levels of oxidative stress can have beneficial effects on cardiovascular health. These include regulating vascular tone by promoting blood vessel dilation, supporting endothelial function through nitric oxide production, and enhancing the immune response to prevent infections. Additionally, oxidative stress can stimulate cellular adaptation to stress, promote cell survival, and encourage angiogenesis, which helps form new blood vessels to improve blood flow. Oxidative stress also holds promise as a source of biomarkers that could aid in the diagnosis, prognosis, and monitoring of CAD. Specific oxidative markers, such as malondialdehyde (MDA), isoprostanes (isoP), ischemia-modified albumin, and antioxidant enzyme activity, have been identified as potential indicators of disease severity and therapeutic response. This review explores the dual nature of oxidative stress in atherosclerosis and CAD, examining its mechanisms in disease pathogenesis as well as its emerging role in clinical diagnostics and targeted therapies. The future directions for research aimed at harnessing the diagnostic and therapeutic potential of oxidative stress biomarkers are also discussed. Understanding the balance between the detrimental and beneficial effects of oxidative stress could lead to innovative approaches in the prevention and management of CAD.

Anti-inflammatory effect of colchicine on organ damage during the perioperative period of cardiac surgery: a study protocol for a multicentre, randomised, double-blind, placebo-controlled clinical trial

INTRODUCTION

The systemic inflammatory response syndrome during the perioperative period of cardiac surgery can lead to serious postoperative complications and significantly increase the hospital mortality rate. Colchicine, a widely used traditional anti-inflammatory drug, has good clinical value in cardiovascular anti-inflammatory therapy. Our preliminary single-centre study had confirmed the protective value of colchicine in patients undergoing cardiac surgery with cardiopulmonary bypass. For this multicentre investigation, we aim to further validate the anti-inflammatory and organ-protective effects of low-dose colchicine during the perioperative period in a low-risk population.

METHODS AND ANALYSIS

This study is a multicentre, randomised, double-blind, placebo-controlled clinical trial. A total of 768 patients undergoing elective cardiac surgery will be enrolled from eight heart centres in China. The participants will be randomly assigned to two groups: the colchicine group will receive low-dose colchicine (0.5 mg once-a-day dosing regimen (QD) orally for 3 days before the surgery and 0.5 mg dosing frequency of every other day (QOD) continuously for 10 days after the surgery), whereas the placebo group will be given starch tablets for the same time and dosage. Primary endpoints are the occurrence of postoperative inflammatory diseases, including postoperative atrial fibrillation, acute respiratory distress syndrome, preoperative myocardial injury and post-pericardiotomy syndrome. Secondary endpoints included laboratory tests on postoperative days 1, 3, 5, 7 and 10, intensive care unit data, APACHE II score, Murray lung injury score, medication-related gastrointestinal reactions, 30-day and 90-day all-cause mortality, surgical data, chest radiograph on postoperative days 1, 2 and 3, and chest CT within 14 days after surgery.

ETHICS AND DISSEMINATION

This research has received approval from the Medical Ethics Committee of Affiliated Nanjing Drum Tower Hospital, Nanjing University Medical College (approval number 2023-366-01). The study findings will be made available by publishing them in an open access journal.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT06118034).

Strategies to attenuate maladaptive inflammatory response associated with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) initiates an intense inflammatory response due to various factors: conversion from pulsatile to laminar flow, cold cardioplegia, surgical trauma, endotoxemia, ischemia-reperfusion injury, oxidative stress, hypothermia, and contact activation of cells by the extracorporeal circuit. Redundant and overlapping inflammatory cascades amplify the initial response to produce a systemic inflammatory response, heightened by coincident activation of coagulation and fibrinolytic pathways. When unchecked, this inflammatory response can become maladaptive and lead to serious postoperative complications. Concerted research efforts have been made to identify technical refinements and pharmacologic interventions that appropriately attenuate the inflammatory response and ultimately translate to improved clinical outcomes. Surface modification of the extracorporeal circuit to increase biocompatibility, miniaturized circuits with sheer resistance, filtration techniques, and minimally invasive approaches have improved clinical outcomes in specific populations. Pharmacologic adjuncts, including aprotinin, steroids, monoclonal antibodies, and free radical scavengers, show real promise. A multimodal approach incorporating technical, circuit-specific, and pharmacologic strategies will likely yield maximal clinical benefit.

Pharmaceutical Modulation of Intracranial Aneurysm Development and Rupture

Management of intracranial aneurysms (IAs) is determined by patient age, risk of rupture, and comorbid conditions. While endovascular and microsurgical interventions offer solutions to mitigate the risk of rupture, pharmacological management strategies may complement these approaches or serve as alternatives in appropriate cases. The pathophysiology of IAs allows for the targeting of inflammation to prevent the development and rupture of IAs. The aim of this review is to provide an updated summary of different pharmaceutical management strategies for IAs. Acetylsalicylic acid and renin-angiotensin-aldosterone system (RAAS) inhibitor antihypertensives have some evidence supporting their protective effect. Studies of selective cyclooxygenase-2 (COX-2) inhibitors, statins, ADP inhibitors, and other metabolism-affecting drugs have demonstrated inconclusive findings regarding their association with aneurysm growth or rupture. In this manuscript, we highlight the evidence supporting each drug's effectiveness.

Albumin Thiolation and Oxidative Stress Status in Patients with Aortic Valve Stenosis

Recent evidence indicates that reactive oxygen species play an important causative role in the onset and progression of valvular diseases. Here, we analyzed the oxidative modifications of albumin (HSA) occurring on Cysteine 34 and the antioxidant capacity of the serum in 44 patients with severe aortic stenosis (36 patients underwent aortic valve replacement and 8 underwent a second aortic valve substitution due to a degenerated bioprosthetic valve), and in 10 healthy donors (controls). Before surgical intervention, patients showed an increase in the oxidized form of albumin (HSA-Cys), a decrease in the native reduced form (HSA-SH), and a significant reduction in serum free sulfhydryl groups and in the total serum antioxidant activity. Patients undergoing a second valve replacement showed levels of HSA-Cys, free sulfhydryl groups, and total antioxidant activity similar to those of controls. In vitro incubation of whole blood with aspirin (ASA) significantly increased the free sulfhydryl groups, suggesting that the in vivo treatment with ASA may contribute to reducing oxidative stress. We also found that N-acetylcysteine and its amide derivative were able to regenerate HSA-SH. In conclusion, the systemic oxidative stress reflected by high levels of HSA-Cys is increased in patients with aortic valve stenosis. Thiol-disulfide breaking agents regenerate HSA-SH, thus paving the way to the use these compounds to mitigate the oxidative stress occurring in the disease.

Antioxidant Properties of Oral Antithrombotic Therapies in Atherosclerotic Disease and Atrial Fibrillation

The thrombosis-related diseases are one of the leading causes of illness and death in the general population, and despite significant improvements in long-term survival due to remarkable advances in pharmacologic therapy, they continue to pose a tremendous burden on healthcare systems. The oxidative stress plays a role of pivotal importance in thrombosis pathophysiology. The anticoagulant and antiplatelet drugs commonly used in the management of thrombosis-related diseases show several pleiotropic effects, beyond the antithrombotic effects. The present review aims to describe the current evidence about the antioxidant effects of the oral antithrombotic therapies in patients with atherosclerotic disease and atrial fibrillation.

The Effect of Off-Pump Coronary Artery Bypass Grafting in Patients on Aspirin Therapy until Surgery Day

Coronary artery bypass grafting (CABG) is widely used to treat coronary artery disease, and intraoperative and postoperative bleeding is one of the major factors affecting the efficacy and mortality of CABG. To overcome the adverse effects of extracorporeal circulation (CPB), nonextracorporeal coronary artery bypass grafting (OPCABG) has become the main modality of CABG but is still prone to thromboembolic events. Whether antiplatelet agents should be clinically applied before CABG, especially OPCABG, remains controversial. Aspirin is currently the most important perioperative oral antiplatelet agent for coronary artery bypass graft surgery. In this study, we evaluated the effect of continuing aspirin therapy before OPCABG and observed perioperative performance and physiological indicators to find evidence for continuing aspirin therapy before surgery in China. The study showed that preoperative aspirin application had a positive effect on enhancing early postoperative platelet inhibition without increasing the incidence of adverse effects such as cardiovascular events. This provides an important clinical reference for whether antiplatelet agents should be applied before CABG, especially OPCABG.

A Pivotal Role of the Nrf2 Signaling Pathway in Spinal Cord Injury: A Prospective Therapeutics Study

The nuclear erythroid 2-related factor 2 (Nrf2) signaling pathway has a main role against oxidative stress and inflammation. Spinal Cord Injury (SCI) leads to the high secretion of inflammatory cytokines and reactive oxygen species, which disturbs nervous system function and regeneration. Several studies have indicated that the activation of the Nrf2 signaling pathway may be effective against inflammation after SCI. The experimental studies have indicated that many chemical and natural agents act as Nrf2 inducer, which inhibits the SCI progression. Thus, the finding of novel Nrf2- inducer anti-inflammatory agents may be a valuable approach in drug discovery. In the present review, we discussed the Nrf2 signal pathway and crosstalk with the NF-κB pathway and also the impact of this pathway on inflammation in animal models of SCI. Furthermore, we discussed the regulation of Nrf2 by several phytochemicals and drugs, as well as their effects on the SCI inhibition. Therefore, the current study presented a new hypothesis of the development of anti-inflammatory agents that mediate the Nrf2 signaling pathway for treating the SCI outcomes.

Responses of the Nrf2/Keap1 signaling pathway in Mugilogobius abei (M. abei) exposed to environmentally relevant concentration aspirin

Aspirin (ASA) is a widely used non-steroidal anti-inflammatory drug. Its high detection frequency in various waterborne and environmental residues has drawn wide attention. Limited information were provided for the effects of aspirin exposure on oxidative stress signaling pathway in fish, which is closely related to pathological and immunological process of fish. In this study, a small fish - Mugilogobius abei (M. abei) distributing widely in aquatic ecosystems in southern China, was employed as testing organism and the key genes of the detoxification metabolism were cloned for the first time. The responses of Nrf2/Keap1 signaling pathway were investigated under the environmentally relevant concentration aspirin exposure (0.5 μg L^-1, 5 μg L^-1, and 50 μg L^-1) for 24 h, 72 h, and 168 h then. The transcriptional expression of the key genes (Nrf2, Keap1, GCLC, GPx, GST, SOD, CAT, Trx2, and TrxR) as well as the changes of the related enzymatic activities (GPx, GST, SOD, and CAT) and GSH and MDA content were also determined. Results showed that Nrf2 and Keap1 gene expression displayed a negative correlation to some extent under ASA exposure, the transcriptional expressions of the downstream related genes (GCLC, GST, SOD, CAT, Trx2, and TrxR) in Nrf2/Keap1 signaling pathway showed inhibition at 24 h but induction at 72 h and 168 h. At the protein level, ASA exposure can improve the antioxidant capacity by increasing GSH synthesis and enzymatic activity of GPx, GST, SOD, and CAT to reduce the degree of lipid peroxidation. We proposed that ASA exposure may interfere with the redox balance in M. abei at an early stage but sub-chronic ASA exposure can activate the Nrf2 signaling pathway to improve the antioxidant capacity of M. abei.

A new strategy for the treatment of atherothrombosis - inhibition of inflammation

Improvement in the prognosis of patients at risk of atherothrombotic events is based on three pillars - slowing down the process of atherogenesis (i.e. the development of atherosclerotic plaque), stabilizing the current atherosclerotic plaque, and reducing the risk of thrombotic occlusion in cases with unstable atherosclerotic plaque. The current prophylaxis has so far taken into consideration the adjustment of several risk factors, including dyslipidemia, arterial hypertension, smoking, and diabetes through lifestyle changes or pharmacological therapies. An essential part of prophylaxis is the anti-thrombotic strategy, especially anti-platelet therapy. Recently, a new pathway has been developed, based on reducing the activity of the inflammatory process with NLRP3 inflammasome, specifically a monoclonal antibody against interleukin 1beta (canakinumab). The efficacy and safety of this treatment, in secondary prevention, were documented in the CANTOS study. Other therapeutic procedures, including suppression of the inflammatory component of atherogenesis, are at the stage of clinical assessment.

Aspirin inhibits osteoclast formation and wear-debris-induced bone destruction by suppressing mitogen-activated protein kinases

Excessive osteoclast recruitment and activation is the chief cause of periprosthetic osteolysis and subsequent aseptic loosening, so blocking osteolysis may be useful for protecting against osteoclastic bone resorption. We studied the effect of aspirin on titanium (Ti)-particle-induced osteolysis in vivo and in vitro using male C57BL/6J mice randomized to sham (sham surgery), Ti (Ti particles), low-dose aspirin (Ti/5 mg·kg^-1 ·d^-1 aspirin), and high-dose aspirin (Ti/30 mg·kg^-1 ·d^-1 aspirin). After 2 weeks, a three-dimensional reconstruction evaluation using micro-computed tomography and histomorphology assessment were performed on murine calvariae. Murine hematopoietic macrophages and RAW264.7 lineage cells were studied to investigate osteoclast formation and function. Aspirin attenuated Ti-particle-induced bone erosion and reduced osteoclasts. In vitro, aspirin suppressed osteoclast formation, osteoclastic-related gene expression, and osteoclastic bone erosion in a dose-dependent manner. Mechanically, aspirin reduced osteoclast formation by suppressing receptor activator of nuclear factor kappa-B ligand-induced activation of extracellular signal-related kinase, p-38 mitogen-activated protein kinase, and c-Jun N-terminal kinase. Thus, aspirin may be a promising option for preventing and curing osteoclastic bone destruction, including peri-implant osteolysis.

Aspirin suppresses neuronal apoptosis, reduces tissue inflammation, and restrains astrocyte activation by activating the Nrf2/HO-1 signaling pathway

The nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element signaling pathway plays a substantial role in preventing oxidative stress-related diseases. Aspirin has been shown to exert several pharmacological effects by inducing the expression of the heme oxygenase-1 (HO-1) protein. However, the effects of aspirin on spinal cord injury (SCI) have rarely been studied. Therefore, we sought to investigate the neuroprotective effects of aspirin after SCI. We employed a spinal cord contusion model in Sprague-Dawley rats, and aspirin was administered intraperitoneally for 7 days. Nissl staining showed that the aspirin treatment significantly reduced the loss of motor neurons after SCI compared with vehicle-treated animals. The expression of Nrf2, quinine oxidoreductase 1, and HO-1 proteins was increased in aspirin-treated animals after SCI compared with the vehicle group. In addition, aspirin simultaneously decreased the expression of inflammation-related proteins, such as tumor necrosis factor-α and interleukin-6 after SCI. Moreover, the ratio of apoptotic neurons in the anterior horn and the levels of the apoptosis-related proteins caspase-3, cleaved caspase-3, and Bax were significantly decreased in the aspirin group compared with the vehicle group. Immunofluorescence staining was used to detect the colocalization of NeuN and HO-1, and the results showed that aspirin significantly increased expression of the HO-1 protein in neurons. In addition, western blots and immunofluorescence staining showed aspirin restrained astrocyte activation. In conclusion, aspirin induces neuroprotective effects by inhibiting astrocyte activation and apoptosis after SCI through the activation of the Nrf2/HO-1 signaling pathway.

Effects of on-pump versus off-pump coronary artery bypass grafting on myocardial metabolism

BACKGROUND

On-pump coronary artery bypass grafting (ON-PCABG) and off-pump coronary artery bypass grafting (OF-PCABG) greatly affect myocardial metabolism (MCMB). However, no study has systematically explored and compared the impacts of ON-PCABG and OF-PCABG on MCMB. This study will aim to explore and to compare the effects of ON-PCABG and OF-PCABG on MCMB systematically.

METHODS

We will conduct the comprehensive literature search from the following electronic databases from inception to the present: Cochrane Library, EMBASE, MEDILINE, CINAHL, AMED and 4 Chinese databases without language restrictions. This systematic review will only concern randomized controlled trials (RCTs) and case-control studies of ON-PCABG and OF-PCABG on MCMB. The methodological quality of each entered study will be assessed by using Cochrane risk of bias tool.

RESULTS

Primary outcomes include myocardial cellular markers, myocardial lactate, oxygen utilization, pyruvate, and intramyocardial concentrations of glucose, urea and lactate. Secondary outcome comprises of glutathione, superoxide dismutase, myeloperoxidase, and oxidative stress and any other complications post surgery.

CONCLUSION

This study will provide a high-quality synthesis and will assess and compare the effects of ON-PCABG and OF-PCABG on MCMB based on the current relevant literature evidence.

DISSEMINATION AND ETHICS

The results will be submitted to peer-reviewed journals for publication. This study does not require ethic approval, because it only analyzes the data from published literature.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019125381.

Strategies to decrease oxidative stress biomarker levels in human medical conditions: A meta-analysis on 8-iso-prostaglandin F2α

The widespread detection of elevated oxidative stress levels in many medical conditions has led to numerous efforts to design interventions to reduce its effects. Efforts have been wide-ranging, from dietary changes to administration of antioxidants, supplements, e.g., omega-3-fatty acids, and many medications. However, there is still no systemic assessment of the efficacy of treatments for oxidative stress reduction across a variety of medical conditions. The goal of this meta-analysis is, by combining multiple studies, to quantitate the change in the levels of the popular oxidative stress biomarker 8-iso-prostaglandin F2α (8-iso-PGF2α) after a variety of treatment strategies in human populations. Nearly 350 unique publications with 180 distinct strategies were included in the analysis. For each strategy, the difference between pre- or placebo and post-treatment levels calculated using Hedges' g value of effect. In general, administration of antibiotics, antihyperlipidemic agents, or changes in lifestyle (g = - 0.63, - 0.54, and 0.56) had the largest effect. Administration of supplements, antioxidants, or changes in diet (g = - 0.09, - 0.28, - 0.12) had small quantitative effects. To fully interpret the effectiveness of these treatments, comparisons to the increase in g value for each medical condition is required. For example, antioxidants in populations with coronary artery disease (CAD) reduce the 8-iso-PGF2α levels by g = - 0.34 ± 0.1, which is quantitatively considered a small effect. However, CAD populations, in comparison to healthy populations, have an increase in 8-iso-PGF2α levels by g = 0.38 ± 0.04; therefore, the overall reduction of 8-iso-PGF2α levels is ≈ 90% by this treatment in this specific medical condition. In conclusion, 8-iso-PGF2α levels can be reduced not only by antioxidants but by many other strategies. Not all strategies are equally effective at reducing 8-iso-PGF2α levels. In addition, the effectiveness of any strategy can be assessed only in relation to the medical condition investigated.

Pre-operative use of aspirin in patients undergoing coronary artery bypass grafting: a systematic review and updated meta-analysis

Background

Aspirin therapy improves saphenous vein graft (SVG) patency in patients undergoing coronary artery bypass graft (CABG), however, its use in the pre-operative period remains controversial. Therefore, we conducted a systematic review and meta-analysis of randomized-controlled trials (RCTs) to update the evidence about risk and benefits of pre-operative aspirin therapy in patients undergoing CABG.

Methods

Electronic databases (Medline, Embase, PubMed, Cochrane Library, and Scopus) were searched to identify RCTs evaluating the effect of aspirin versus placebo/control before CABG. Two investigators independently and in duplicate screened citations and extracted data and rated the risk of bias. The strength of evidence was appraised using the Grading of Recommendation Assessment, Development, and Evaluation (GRADE) approach. Meta-analysis was performed using a random-effects model. The main outcomes of interest were 30-day mortality, peri-operative myocardial infarction (MI), chest tube drainage and SVG occlusion.

Results

A total of 13 RCTs involving 4,377 participants (2,266/2,111 pre-operative aspirin/control) met the inclusion criteria. Pre-operative aspirin reduced the risk of SVG occlusion [risk ratio (RR): 0.69, 95% confidence interval (CI): 0.49-0.97, P=0.03, I²=16%], but no differences in mortality (RR: 1.41, 95% Cl: 0.73-2.74, I²=0%) and MI (RR: 0.84, 95% CI: 0.69-1.03, I²=0%) were found. However, pre-operative aspirin increased chest tube drainage (MD: 100.40 mL, 95% CI: 24.32-176.47 mL, P=0.01, I²=84%) and surgical re-exploration (RR: 1.52, 95% CI: 1.02-2.27, P=0.04, I²=8%), with no significant difference in RBC transfusion (RR: 1.06, 95% CI: 0.90-1.25, I²=35%).

Conclusions

Based on trials where the rated body of evidence was of low to very-low quality, pre-operative aspirin improves SVG patency but increases chest tube drainage and need for surgical re-exploration.

Lipid peroxidation in cardiac surgery: towards consensus on biomonitoring, diagnostic tools and therapeutic implementation

This review focuses on oxidative stress and more specifically lipid peroxidation in cardiac surgery, one of the fundamental theories of perioperative complications. We present the molecular pathways leading to lipid peroxidation and integrate analytical methods that allow detection of lipid peroxidation markers in the fluid phase with those focusing on volatile compounds in exhaled breath. In order to explore the accumulated data in the literature, we present a systematic review of quantitative analysis of malondialdehyde, a widely used lipid peroxidation product at various stages of cardiac surgery. This exploration reveals major limitations of existing studies in terms of variability of reported values and significant gaps due to discrete and variable sampling times during surgery. We also appraise methodologies that allow real-time and continuous monitoring of oxidative stress. Complimentary techniques highlight that beyond the widely acclaimed contribution of the cardiopulmonary bypass technology and myocardial reperfusion injury, the use of diathermy contributes significantly to intraoperative lipid peroxidation. We conclude that there is an urgent need to implement the theory of oxidative stress towards a paradigm change in the clinical practice. Firstly, we need to acquire definite and irrefutable information on the link between lipid peroxidation and post-operative complications by building international consensus on best analytical approaches towards generating qualitatively and quantitatively comparable datasets in coordinated multicentre studies. Secondly, we should move away from routine low-risk surgeries towards higher risk interventions where there is major unmet clinical need for improving patient journey and outcomes. There is also need for consensus on best therapeutic interventions which could be tested in convincing large scale clinical trials. As future directions, we propose combination of fluid phase platforms and 'metabography', an extended form of capnography-including real-time analysis of lipid peroxidation and volatile footprints of metabolism-for better patient phenotyping prior to and during high risk surgery towards molecular prediction, stratification and monitoring of the patient's journey.

Management of severe perioperative bleeding: guidelines from the European Society of Anaesthesiology: First update 2016

: The management of perioperative bleeding involves multiple assessments and strategies to ensure appropriate patient care. Initially, it is important to identify those patients with an increased risk of perioperative bleeding. Next, strategies should be employed to correct preoperative anaemia and to stabilise macrocirculation and microcirculation to optimise the patient's tolerance to bleeding. Finally, targeted interventions should be used to reduce intraoperative and postoperative bleeding, and so prevent subsequent morbidity and mortality. The objective of these updated guidelines is to provide healthcare professionals with an overview of the most recent evidence to help ensure improved clinical management of patients. For this update, electronic databases were searched without language restrictions from 2011 or 2012 (depending on the search) until 2015. These searches produced 18 334 articles. All articles were assessed and the existing 2013 guidelines were revised to take account of new evidence. This update includes revisions to existing recommendations with respect to the wording, or changes in the grade of recommendation, and also the addition of new recommendations. The final draft guideline was posted on the European Society of Anaesthesiology website for four weeks for review. All comments were collated and the guidelines were amended as appropriate. This publication reflects the output of this work.

Prostanoids in the pathophysiology of human coronary artery

Coronary artery disease is one of the leading causes of death in wordwide. There is growing evidence that prostanoids are involved in the physiology and pathophysiology of the human coronary artery by controlling vascular tone, remodelling of the vascular wall or angiogenesis. In this review, the production of prostanoids and the expression of prostanoid receptors in human coronary artery in health or disease are described. In addition, the interactions between sex hormones and prostanoids, their participations in the development of coronary artery diseases have been addressed. Globally, most of the studies performed in human coronary artery preparations have shown that prostacyclin (PGI₂) has beneficial effects by inducing vasodilatation and promoting angiogenesis while reverse effects are confirmed by thromboxane A₂ (TxA₂). More studies are needed to determine the roles of the other prostanoids (PGE₂, PGD₂ and PGF_2α) in vascular functions of the human coronary artery. Finally, in addition to the in vitro data about the human coronary artery, myocardial infarction induced by cyclooxygenase-2 (COX-2) inhibitor and the protective effects of aspirin after coronary artery bypass surgery suggest that prostanoids are key mediators in coronary homeostasis.

Myocardial Oxidative Stress in Infants Undergoing Cardiac Surgery

Cardiac surgery for congenital heart disease often necessitates a period of myocardial ischemia during cardiopulmonary bypass and cardioplegic arrest, followed by reperfusion after aortic cross-clamp removal. In experimental models, myocardial ischemia-reperfusion is associated with significant oxidative stress and ventricular dysfunction. A prospective observational study was conducted in infants (<1 year) who underwent elective surgical repair of a ventricular septal defect (VSD) or tetralogy of Fallot (TOF). Blood samples were drawn following anesthetic induction (baseline) and directly from the coronary sinus at 1, 3, 5, and 10 min following aortic cross-clamp removal. Samples were analyzed for oxidant stress using assays for thiobarbituric acid-reactive substances, protein carbonyl, 8-isoprostane, and total antioxidant capacity. For each subject, raw assay data were normalized to individual baseline samples and expressed as fold-change from baseline. Results were compared using a one-sample t test with Bonferroni correction for multiple comparisons. Sixteen patients (ten with TOF and six with VSD) were enrolled in the study, and there were no major postoperative complications observed. For the entire cohort, there was an immediate, rapid increase in myocardial oxidative stress that was sustained for 10 min following aortic cross-clamp removal in all biomarker assays (all P < 0.01), except total antioxidant capacity. Infant cardiac surgery is associated with a rapid, robust, and time-dependent increase in myocardial oxidant stress as measured from the coronary sinus in vivo. Future studies with larger enrollment are necessary to assess any association between myocardial oxidative stress and early postoperative outcomes.

Aspirin induces Nrf2-mediated transcriptional activation of haem oxygenase-1 in protection of human melanocytes from H2 O2 -induced oxidative stress

The removal of hydrogen peroxide (H2 O2 ) by antioxidants has been proven to be beneficial to patients with vitiligo. Aspirin (acetylsalicylic acid, ASA) has antioxidant activity and has great preventive and therapeutical effect in many oxidative stress-relevant diseases. Whether ASA can protect human melanocytes against oxidative stress needs to be further studied. Here, we investigated the potential protective effect and mechanisms of ASA against H2 O2 -induced oxidative injury in human melanocytes. Human melanocytes were pre-treated with different concentrations of ASA, followed by exposure to 1.0 mM H2 O2 . Cell apoptosis, intracellular reactive oxygen species (ROS) levels were evaluated by flow cytometry, and cell viability was determined by an Cell Counting Kit-8 assay. Total and phosphorylated NRF2 expression, NRF2 nuclear translocation and antioxidant response element (ARE) transcriptional activity were assayed with or without Nrf2-siRNA transfection to investigate the possible molecular mechanisms. Concomitant with an increase in viability, pre-treatment of 10-90 μmol/l ASA resulted in decreased rate of apoptotic cells, lactate dehydrogenase release and intracellular ROS levels in primary human melanocytes. Furthermore, we found ASA dramatically induced NRF2 nuclear translocation, enhanced ARE-luciferase activity, increased both p- NRF2 and total NRF2 levels, and induced the expression of haem oxygenase-1 (HO-1) in human melanocytes. In addition, knockdown of Nrf2 expression or pharmacological inhibition of HO-1 abrogated the protective action of ASA on melanocytes against H2 O2 -induced cytotoxicity and apoptosis. These results suggest that ASA protects human melanocytes against H2 O2 -induced oxidative stress via Nrf2-driven transcriptional activation of HO-1.

Effect of Preoperative Aspirin Replacement With Enoxaparin in Patients Undergoing Primary Isolated On-Pump Coronary Artery Bypass Grafting

Management of preoperative antiplatelet therapy in coronary artery bypass grafting (CABG) is variable among surgeons: guidelines collide with prejudices because replacement of aspirin with low-molecular-weight heparin is still performed because of a presumed minor bleeding risk. This study aims to analyze postoperative bleedings and complications in patients scheduled for elective primary isolated on-pump CABG, depending on preoperative aspirin treatment or its replacement with enoxaparin. In this cohort study, we propensity score matched 200 patients in whom aspirin was stopped at least 5 days before CABG and replaced with enoxaparin and 200 patients who continued aspirin therapy until the day before surgery. Postoperative bleedings and complications were monitored during hospitalization. Among patients who continued aspirin treatment, mean overall bleeding was 701.0 ± 334.6 ml, whereas in the matched enoxaparin group, it was significantly greater (882.6 ± 64.6 ml, p value <0.001); this was associated with reduced postoperative complications, lower values of postoperative C-reactive protein in aspirin takers, and a presumed protective effect for statins. After propensity score adjustment, aspirin treatment carried a protective effect against major postoperative bleeding (odds ratio 0.312, p = 0.001). In conclusion, postoperative bleeding is reduced in patients who continued aspirin, likely due to a reduction in postoperative inflammation. The practice of empirically discontinuing aspirin and replacing it with enoxaparin before CABG should be abandoned. Patients with coronary artery disease referred to CABG should continue antiplatelet medications until the surgical procedure. Those results might be extended to patients under oral anticoagulant therapy requiring CABG.

The isoprostanes--25 years later

Isoprostanes (IsoPs) are prostaglandin-like molecules generated independent of the cyclooxygenase (COX) by the free radical-induced peroxidation of arachidonic acid. The first isoprostane species discovered were isomeric to prostaglandin F2α and were thus termed F2-IsoPs. Since the initial discovery of the F2-IsoPs, IsoPs with differing ring structures have been identified as well as IsoPs from different polyunsaturated fatty acids, including eicosapentaenoic acid and docosahexanenoic acid. The discovery of these molecules in vivo in humans has been a major contribution to the field of lipid oxidation and free radical research over the course of the past 25 years. These molecules have been determined to be both biomarkers and mediators of oxidative stress in numerous disease settings. This review focuses on recent developments in the field with an emphasis on clinical research. Special focus is given to the use of IsoPs as biomarkers in obesity, ischemia-reperfusion injury, the central nervous system, cancer, and genetic disorders. Additionally, attention is paid to diet and lifestyle factors that can affect endogenous levels of IsoPs. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance."

A high precision method for quantitative measurements of reactive oxygen species in frozen biopsies

OBJECTIVE

An electron paramagnetic resonance (EPR) technique using the spin probe cyclic hydroxylamine 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CMH) was introduced as a versatile method for high precision quantification of reactive oxygen species, including the superoxide radical in frozen biological samples such as cell suspensions, blood or biopsies.

MATERIALS AND METHODS

Loss of measurement precision and accuracy due to variations in sample size and shape were minimized by assembling the sample in a well-defined volume. Measurement was carried out at low temperature (150 K) using a nitrogen flow Dewar. The signal intensity was measured from the EPR 1st derivative amplitude, and related to a sample, 3-carboxy-proxyl (CP•) with known spin concentration.

RESULTS

The absolute spin concentration could be quantified with a precision and accuracy better than ±10 µM (k = 1). The spin concentration of samples stored at -80°C could be reproduced after 6 months of storage well within the same error estimate.

CONCLUSION

The absolute spin concentration in wet biological samples such as biopsies, water solutions and cell cultures could be quantified with higher precision and accuracy than normally achievable using common techniques such as flat cells, tissue cells and various capillary tubes. In addition; biological samples could be collected and stored for future incubation with spin probe, and also further stored up to at least six months before EPR analysis, without loss of signal intensity. This opens for the possibility to store and transport incubated biological samples with known accuracy of the spin concentration over time.

Beta-thromboglobulin as a marker of perioperative myocardial infarction in patients undergoing coronary artery bypass grafting following aspirin discontinuation

Perioperative myocardial infarction (PMI) following coronary artery bypass grafting (CABG) is associated with significant morbidity and mortality. The aim of this study was to assess platelet activation and oxidative stress in the setting of PMI in patients undergoing CABG. We studied 108 consecutive patients who stopped taking low-dose aspirin 7-10 days prior to elective isolated on- or off-pump CABG. β-thromboglobulin (β-TG), thromboxane B2 (TXB2) and 8-iso-prostaglandin F2α (8-iso-PGF2α), a marker of oxidative stress, were measured at the baseline and 5-7 days postoperatively. Aspirin (150 mg/d) was administered every morning since 12 hours after CABG. Mean baseline β-TG was 58.5 ± 10.3 IU/ml, TXB2 was 143.6 ± 28.5 ng/ml and 8-iso-PGF2α was 355.2 ± 40.7 pg/ml. Postoperatively, after administration of 4-6 doses of aspirin, β-TG increased by 16.7% and 8-iso-PGF2α increased by 17.2% 5-7 days after surgery (p = 0.005 and p < 0.001, respectively). TXB2 decreased by 99.7% to 410.3 ± 52.1 pg/ml (p < 0.001). Nine patients (8.3%) developed PMI. Baseline β-TG and TXB2, together with postoperative β-TG and 8-iso-PGF2α were higher in PMI patients than in the remaining subjects (all, p < 0.05). Multivariate analysis showed that baseline β-TG (OR: 1.28; 95% CI: 1.05-1.57, p = 0.015) was the only independent predictor of PMI. In conclusion, we demonstrated that increased platelet activation and thromboxane production, observed in patients not taking aspirin till the day of CABG, contribute to the occurrence of PMI in early postoperative period.