Cardioprotection against ischaemia/reperfusion by vitamins C and E plus n-3 fatty acids: molecular mechanisms and potential clinical applications. Clin Sci (Lond). 2013;124:1-15. [PMID: 22963444 DOI: 10.1042/cs20110663]

Ionizing Radiation-Induced Oxidative Stress in Computed Tomography-Effect of Vitamin C on Prevention of DNA Damage: PREVIR-C Randomized Controlled Trial Study Protocol

Exposure to ionizing radiation (IR) is inevitable in various X-ray imaging examinations, with computed tomography (CT) being a major contributor to increased human radiation exposure. Ionizing radiation may cause structural damage to macromolecules, particularly DNA, mostly through an indirect pathway in diagnostic imaging. The indirect pathway primarily involves the generation of reactive oxygen species (ROS) due to water radiolysis induced by IR, leading to DNA damage, including double-strand breaks (DSB), which are highly cytotoxic. Antioxidants, substances that prevent oxidative damage, are proposed as potential radioprotective agents. This Study Protocol article presents the rationale for selecting vitamin C as a preventive measure against CT-associated IR-induced DNA damage, to be investigated in a randomized placebo-controlled trial, with a full in vivo design, using an oral easy-to-use schedule administration in the outpatient setting, for the single CT examination with the highest total global IR dose burden (contrast-enhanced abdomen and pelvis CT). The study also aims to explore the mediating role of oxidative stress, and it has been written in adherence to the Standard Protocol Items recommendations.

Effect of high-dose vitamin C on renal ischemia-reperfusion injury

Acute kidney injury frequently occurs after cardiac surgery, and is primarily attributed to renal ischemia-reperfusion (I/R) injury and inflammation from surgery and cardiopulmonary bypass. Vitamin C, an antioxidant that is often depleted in critically ill patients, could potentially mitigate I/R-induced oxidative stress at high doses. We investigated the effectiveness of high-dose vitamin C in preventing I/R-induced renal injury. The ideal time and optimal dosage for administration were determined in a two-phase experiment on Sprague-Dawley rats. The rats were assigned to four groups: sham, IRC (I/R + saline), and pre- and post-vitC (vitamin C before and after I/R, respectively), with vitamin C administered at 200 mg/kg. Additional groups were examined for dose modification based on the optimal timing determined: V100, V200, and V300 (100, 200, and 300 mg/kg, respectively). Renal I/R was achieved through 45 min of ischemia followed by 24 h of reperfusion. Vitamin C administration during reperfusion significantly reduced renal dysfunction and tubular damage, more than pre-ischemic administration. Doses of 100 and 200 mg/kg during reperfusion reduced oxidative stress markers, including myeloperoxidase and inflammatory responses by decreasing high mobility group box 1 release and nucleotide-binding and oligomerization domain-like receptor 3 inflammasome. Overall beneficial effect was most prominent with 200 mg/kg. The 300 mg/kg dose, however, showed no additional benefits over the IRC group regarding serum blood urea nitrogen and creatinine levels and histological evaluation. During reperfusion, high-dose vitamin C administration (200 mg/kg) significantly decreased renal I/R injury by effectively attenuating the major triggers of oxidative stress and inflammation.

The role of ferroptosis in cardio-oncology

With the rapid development of new generations of antitumor therapies, the average survival time of cancer patients is expected to be continuously prolonged. However, these therapies often lead to cardiotoxicity, resulting in a growing number of tumor survivors with cardiovascular disease. Therefore, a new interdisciplinary subspecialty called "cardio-oncology" has emerged, aiming to detect and treat cardiovascular diseases associated with tumors and antitumor therapies. Recent studies have highlighted the role of ferroptosis in both cardiovascular and neoplastic diseases. The balance between intracellular oxidative stress and antioxidant defense is crucial in regulating ferroptosis. Tumor cells can evade ferroptosis by upregulating multiple antioxidant defense pathways, while many antitumor therapies rely on downregulating antioxidant defense and promoting ferroptosis in cancer cells. Unfortunately, these ferroptosis-inducing antitumor therapies often lack tissue specificity and can also cause injury to the heart, resulting in ferroptosis-induced cardiotoxicity. A range of cardioprotective agents exert cardioprotective effects by inhibiting ferroptosis. However, these cardioprotective agents might diminish the efficacy of antitumor treatment due to their antiferroptotic effects. Most current research on ferroptosis only focuses on either tumor treatment or heart protection but rarely considers both in concert. Therefore, further research is needed to study how to protect the heart during antitumor therapies by regulating ferroptosis. In this review, we summarized the role of ferroptosis in the treatment of neoplastic diseases and cardiovascular diseases and also attempted to propose further research directions for ferroptosis in the field of cardio-oncology.

Potential Role of Natural Antioxidants in Countering Reperfusion Injury in Acute Myocardial Infarction and Ischemic Stroke

Stroke and acute myocardial infarction are leading causes of mortality worldwide. The latter accounts for approximately 9 million deaths annually. In turn, ischemic stroke is a significant contributor to adult physical disability globally. While reperfusion is crucial for tissue recovery, it can paradoxically exacerbate damage through oxidative stress (OS), inflammation, and cell death. Therefore, it is imperative to explore diverse approaches aimed at minimizing ischemia/reperfusion injury to enhance clinical outcomes. OS primarily arises from an excessive generation of reactive oxygen species (ROS) and/or decreased endogenous antioxidant potential. Natural antioxidant compounds can counteract the injury mechanisms linked to ROS. While promising preclinical results, based on monotherapies, account for protective effects against tissue injury by ROS, translating these models into human applications has yielded controversial evidence. However, since the wide spectrum of antioxidants having diverse chemical characteristics offers varied biological actions on cell signaling pathways, multitherapy has emerged as a valuable therapeutic resource. Moreover, the combination of antioxidants in multitherapy holds significant potential for synergistic effects. This study was designed with the aim of providing an updated overview of natural antioxidants suitable for preventing myocardial and cerebral ischemia/reperfusion injuries.

Oxidative Stress in Type 2 Diabetes: Impacts from Pathogenesis to Lifestyle Modifications

Oxidative stress is a critical factor in the pathogenesis and progression of diabetes and its associated complications. The imbalance between reactive oxygen species (ROS) production and the body's antioxidant defence mechanisms leads to cellular damage and dysfunction. In diabetes, chronic hyperglycaemia and mitochondrial dysfunction contribute to increased ROS production, further exacerbating oxidative stress. This oxidative burden adversely affects various aspects of diabetes, including impaired beta-cell function and insulin resistance, leading to disrupted glucose regulation. Additionally, oxidative stress-induced damage to blood vessels and impaired endothelial function contribute to the development of diabetic vascular complications such as retinopathy, nephropathy, and cardiovascular diseases. Moreover, organs and tissues throughout the body, including the kidneys, nerves, and eyes, are vulnerable to oxidative stress, resulting in diabetic nephropathy, neuropathy, and retinopathy. Strategies to mitigate oxidative stress in diabetes include antioxidant therapy, lifestyle modifications, and effective management of hyperglycaemia. However, further research is necessary to comprehensively understand the underlying mechanisms of oxidative stress in diabetes and to evaluate the efficacy of antioxidant interventions in preventing and treating diabetic complications. By addressing oxidative stress, it might be possible to alleviate the burden of diabetes and improve patient outcomes.

Antioxidant Protection against Trastuzumab Cardiotoxicity in Breast Cancer Therapy

Breast cancer is the most frequent malignant neoplastic disease in women, with an estimated 2.3 million cases in 2020 worldwide. Its treatment depends on characteristics of the patient and the tumor. In the latter, characteristics include cell type and morphology, anatomical location, and immunophenotype. Concerning this latter aspect, the overexpression of the HER2 receptor, expressed in 15-25% of tumors, is associated with greater aggressiveness and worse prognosis. In recent times some monoclonal antibodies have been developed in order to target HER2 receptor overexpression. Trastuzumab is part of the monoclonal antibodies used as targeted therapy against HER2 receptor, whose major problem is its cardiac safety profile, where it has been associated with cardiotoxicity. The appearance of cardiotoxicity is an indication to stop therapy. Although the pathophysiological mechanism is poorly known, evidence indicates that oxidative stress plays a fundamental role causing DNA damage, increased cytosolic and mitochondrial ROS production, changes in mitochondrial membrane potential, intracellular calcium dysregulation, and the consequent cell death through different pathways. The aim of this review was to explore the use of antioxidants as adjuvant therapy to trastuzumab to prevent its cardiac toxicity, thus leading to ameliorate its safety profile in its administration.

Myocardial infarction and oxidative damage in animal models: objective and expectations from the application of cysteine derivatives

Reactive oxygen species (ROS) and associated oxidative stress are the main contributors to pathophysiological changes following myocardial infarction (MI), which is the principal cause of death from cardiovascular disease. The glutathione (GSH)/glutathione peroxidase (GPx) system appears to be the main and most active cardiac antioxidant mechanism. Hence, enhancement of the myocardial GSH system might have protective effects in the setting of MI. It follows that by increasing antioxidant capacity, the heart will be able to reduce the damage associated with MI and even prevent/weaken the occurrence of oxidative stress, which is highly ranked among the factors responsible for the occurrence of acute MI. For these reasons, the primary goal of future investigations should be to address the effects of different antioxidative compounds and especially cysteine derivatives like N-acetyl cysteine (NAC) and L-2-oxothiazolidine-4-carboxylic acid (OTC) as precursors responsible for the enhancement of the GSH-related antioxidant system's capacity. It is assumed that this will lay down the basis for elucidation of the mechanisms throughout which applicable doses of OTC will manifest a potentially positive impact in the reduction of adverse effects of acute MI. The inclusion of OTC in the models for prediction of the distribution of oxygen in infarcted animal hearts can help to upgrade existing computational models. Such a model would be based on computational geometries of the heart, but the inclusion of biochemical redox features in addition to angiogenic therapy, despite improvement of the post-infarcted oxygenated outcome could enhance the accuracy of the predictive values of oxygenation.

Potential Antioxidant Multitherapy against Complications Occurring in Sepsis

Septic shock currently represents one of the main causes of mortality in critical patient units with an increase in its incidence in recent years, and it is also associated with a high burden of morbidity in surviving patients. Within the pathogenesis of sepsis, oxidative stress plays an important role. The excessive formation of reactive oxygen species (ROS) leads to mitochondrial damage and vasomotor dysfunction that characterizes those patients who fall into septic shock. Currently, despite numerous studies carried out in patients with septic shock of different causes, effective therapies have not yet been developed to reduce the morbidity and mortality associated with this pathology. Despite the contribution of ROS in the pathophysiology of sepsis and septic shock, most studies performed in humans, with antioxidant monotherapies, have not resulted in promising data. Nevertheless, some interventions with compounds such as ascorbate, N-acetylcysteine, and selenium would have a positive effect in reducing the morbidity and mortality associated with this pathology. However, more studies are required to demonstrate the efficacy of these therapies. Taking into account the multifactorial features of the pathophysiology of sepsis, we put forward the hypothesis that a supplementation based on the association of more than one antioxidant compound should result in a synergistic or additive effect, thus improving the beneficial effects of each of them alone, potentially serving as a pharmacological adjunct resource to standard therapy to reduce sepsis complications. Therefore, in this review, it is proposed that the use of combined antioxidant therapies could lead to a better clinical outcome of patients with sepsis or septic shock, given the relevance of oxidative stress in the pathogenesis of this multi-organ dysfunction.

Shrimp Lipid Prevents Endoplasmic Reticulum-Mediated Endothelial Cell Damage

Shrimp contains a fat that benefits cardiovascular function and may help in the prevention of diseases. The stress of essential cellular organelle endoplasmic reticulum (ER) is linked to endothelial dysfunction and damage. This research aimed at investigating the effect of shrimp lipid (SL) on endothelial cells in response to ER stress, as well as the underlying mechanisms. Human endothelial cells were pretreated with SL (250 and 500 μg/mL) for 24 h, and treated with 0.16 μg/mL of Thapsigargin (Tg) for 24 h. The apoptosis and necrosis were detected by Hoechst 33342/propidium iodide (PI) co-staining. Cellular signaling pathways and ER stress markers were evaluated by Western blot analysis and immunofluorescence. SL protected against ER-induced endothelial cell apoptosis. According to the results, the viability of EA.hy926 cells treated with Tg alone was 44.97 ± 1%, but SL (250 μg/mL) pretreatment increased cell viability to 77.26 ± 3.9%, and SL (500 μg/mL) increased to 72.42 ± 4.3%. SL suppressed the increase in ER stress regulator glucose-regulated protein 78 (GRP78) and attenuated the RNA-dependent protein kinase-like ER eukaryotic initiation factor-2α kinase (PERK) and inositol-requiring ER-to-nucleus signaling protein 1 (IRE1) pathways. SL could inhibit cell damage by reducing the ER-related apoptosis protein, C/EBPα-homologous protein (CHOP), induced by ER stress. Taken together, we found the protective effect and mechanism of SL in protecting ER stress-induced endothelial cell apoptosis through suppression of the ER stress pathway. The findings may support the potential use of SL as an approach with a protective effect on endothelial cells.

Cardioprotective Antioxidant and Anti-Inflammatory Mechanisms Induced by Intermittent Hypobaric Hypoxia

More than 80 million people live and work (in a chronic or intermittent form) above 2500 masl, and 35 million live in the Andean Mountains. Furthermore, in Chile, it is estimated that 100,000 people work in high-altitude shifts, where stays in the lowlands are interspersed with working visits in the highlands. Acute exposure to high altitude has been shown to induce oxidative stress in healthy human lowlanders due to increased free radical formation and decreased antioxidant capacity. However, intermittent hypoxia (IH) induces preconditioning in animal models, generating cardioprotection. Here, we aim to describe the responses of a cardiac function to four cycles of intermittent hypobaric hypoxia (IHH) in a rat model. The twelve adult Wistar rats were randomly divided into two equal groups, a four-cycle of IHH and a normobaric hypoxic control. Intermittent hypoxia was induced in a hypobaric chamber in four continuous cycles (1 cycle = 4 days of hypoxia + 4 days of normoxia), reaching a barometric pressure equivalent to 4600 m of altitude (428 Torr). At the end of the fourth cycle, cardiac structural and functional variables were also determined by echocardiography; furthermore, cardiac oxidative stress biomarkers (4-Hydroxynonenal, HNE; nitrotyrosine, NT), antioxidant enzymes, and NLRP3 inflammasome panel expression are also determined. Our results show a higher ejection and a shortening fraction of the left ventricle function by the end of the fourth cycle. Furthermore, cardiac tissue presented a decreased expression of antioxidant proteins. However, a decrease in IL-1β, TNF-αn, and oxidative stress markers is observed in IHH compared to normobaric hypoxic controls. Non-significant differences were found in protein levels of NLRP3 and caspase-1. IHH exposure determines structural and functional heart changes. These findings suggest that initial states of IHH are beneficial for cardiovascular function and protection.

Antioxidant Cardioprotection against Reperfusion Injury: Potential Therapeutic Roles of Resveratrol and Quercetin

Ischemia-reperfusion myocardial damage is a paradoxical tissue injury occurring during percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) patients. Although this damage could account for up to 50% of the final infarct size, there has been no available pharmacological treatment until now. Oxidative stress contributes to the underlying production mechanism, exerting the most marked injury during the early onset of reperfusion. So far, antioxidants have been shown to protect the AMI patients undergoing PCI to mitigate these detrimental effects; however, no clinical trials to date have shown any significant infarct size reduction. Therefore, it is worthwhile to consider multitarget antioxidant therapies targeting multifactorial AMI. Indeed, this clinical setting involves injurious effects derived from oxygen deprivation, intracellular pH changes and increased concentration of cytosolic Ca²⁺ and reactive oxygen species, among others. Thus, we will review a brief overview of the pathological cascades involved in ischemia-reperfusion injury and the potential therapeutic effects based on preclinical studies involving a combination of antioxidants, with particular reference to resveratrol and quercetin, which could contribute to cardioprotection against ischemia-reperfusion injury in myocardial tissue. We will also highlight the upcoming perspectives of these antioxidants for designing future studies.

An antioxidant system through conjugating superoxide dismutase onto metal-organic framework for cardiac repair

Acute myocardial infarction (AMI) remains a dominant origin of morbidity, mortality and disability worldwide. Increases in reactive oxygen species (ROS) are key contributor to excessive cardiac injury after AMI. Here we developed an immobilized enzyme with Superoxide Dismutase (SOD) activity cross-link with Zr-based metal-organic framework (ZrMOF) (SOD-ZrMOF) for mitigate ROS-caused injury. In vitro and in vivo evidence indicates that SOD-ZrMOF exhibits excellent biocompatibility. By efficiently scavenging ROS and suppressing oxidative stress, SOD-ZrMOF can protect the function of mitochondria, reduce cell death and alleviate inflammation. More excitingly, long-term study using an animal model of AMI demonstrated that SOD-ZrMOF can reduce the infarct area, protect cardiac function, promote angiogenesis and inhibit pathological myocardial remodeling. Therefore, SOD-ZrMOF holds great potential as an efficacious and safe nanomaterial treatment for AMI.

Ferroptosis: Opportunities and Challenges in Myocardial Ischemia-Reperfusion Injury

Ferroptosis is a newly discovered form of regulated cell death dependent on iron and reactive oxygen species (ROS). It directly or indirectly affects the activity of glutathione peroxidases (GPXs) under the induction of small molecules, causing membrane lipid peroxidation due to redox imbalances and excessive ROS accumulation, damaging the integrity of cell membranes. Ferroptosis is mainly characterized by mitochondrial shrinkage, increased density of bilayer membranes, and the accumulation of lipid peroxidation. Myocardial ischemia-reperfusion injury (MIRI) is an unavoidable risk event for acute myocardial infarction. Ferroptosis is closely associated with MIRI, and this relationship is discussed in detail here. This review systematically summarizes the process of ferroptosis and the latest research progress on the role of ferroptosis in MIRI to provide new ideas for the prevention and treatment of MIRI.

Combating Ischemia-Reperfusion Injury with Micronutrients and Natural Compounds during Solid Organ Transplantation: Data of Clinical Trials and Lessons of Preclinical Findings

Although extended donor criteria grafts bear a higher risk of complications such as graft dysfunction, the exceeding demand requires to extent the pool of potential donors. The risk of complications is highly associated with ischemia-reperfusion injury, a condition characterized by high loads of oxidative stress exceeding antioxidative defense mechanisms. The antioxidative properties, along with other beneficial effects like anti-inflammatory, antiapoptotic or antiarrhythmic effects of several micronutrients and natural compounds, have recently emerged increasing research interest resulting in various preclinical and clinical studies. Preclinical studies reported about ameliorated oxidative stress and inflammatory status, resulting in improved graft survival. Although the majority of clinical studies confirmed these results, reporting about improved recovery and superior organ function, others failed to do so. Yet, only a limited number of micronutrients and natural compounds have been investigated in a (large) clinical trial. Despite some ambiguous clinical results and modest clinical data availability, the vast majority of convincing animal and in vitro data, along with low cost and easy availability, encourage the conductance of future clinical trials. These should implement insights gained from animal data.

Effect of pinolenic acid on oxidative stress injury in HepG2 cells induced by H2O2

To investigate the effect and mechanism of pinolenic acid (PNA) on H2O2-induced oxidative stress injury in HepG2 cells. Methods: PNA was used to regulate oxidative stress injury of HepG2 cells induced by H2O2. Quantification of cell survival rate, accumulation of intracellular reactive oxygen species (ROS), and expression levels of anti-oxidation-related genes were determined using MTT, fluorescent probe technology (DCFH-DA), and real-time quantitative reverse transcription polymerase chain technology (qRT-PCR) method, respectively. Meanwhile, the activity of intracellular antioxidant enzymes was determined by biochemical methods. The results showed that PNA improved the survival rate of HepG2 cells induced by H2O2 (29.59%, high-dose group), reduced the accumulation of intracellular ROS (65.52%, high-dose group), and reduced the level of intracellular malondialdehyde (MDA; 65.52%, high-dose group). All these results were dose-dependent, which indicated that PNA can improve oxidative stress damage of cells. Furthermore, the mechanism of PNA regulating oxidative stress was investigated from the gene level. Results showed that under supplementation of PNA, the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) had been improved (39.74%, 17.58%, and 23.83%, high-dose group). Further studies on gene expression which controls the activity of antioxidant enzymes showed that under the regulation of PNA, the expression level of Keap1 gene was decreased, while Nrf2 gene was increased. The expression levels of HO-1 and NQO1 in the downstream of Nrf2 were increased. Results indicated that under the regulation of PNA, Nrf2 was separated from Keap1, entered the nucleus, bound to ARE, and up-regulated the expression levels of HO-1 and NQO1 genes. Conclusion: PNA has a conspicuous improvement effect on oxidative stress damage induced by H2O2 in HepG2 cells. We also found the antioxidant mechanisms of PNA where it protected cells from oxidative stress damage by causing nuclear translocation of Nrf2 gene and up-regulated the expression levels of antioxidant enzymes in the downstream. This shows that PNA prevented oxidative stress by mediating the Keap1/Nrf2 transcriptional pathway and down-regulating enzyme activities.

Joint Cardioprotective Effect of Vitamin C and Other Antioxidants against Reperfusion Injury in Patients with Acute Myocardial Infarction Undergoing Percutaneous Coronary Intervention

Percutaneous coronary intervention (PCI) has long remained the gold standard therapy to restore coronary blood flow after acute myocardial infarction (AMI). However, this procedure leads to the development of increased production of reactive oxygen species (ROS) that can exacerbate the damage caused by AMI, particularly during the reperfusion phase. Numerous attempts based on antioxidant treatments, aimed to reduce the oxidative injury of cardiac tissue, have failed in achieving an effective therapy for these patients. Among these studies, results derived from the use of vitamin C (Vit C) have been inconclusive so far, likely due to suboptimal study designs, misinterpretations, and the erroneous conclusions of clinical trials. Nevertheless, recent clinical trials have shown that the intravenous infusion of Vit C prior to PCI-reduced cardiac injury biomarkers, as well as inflammatory biomarkers and ROS production. In addition, improvements of functional parameters, such as left ventricular ejection fraction (LVEF) and telediastolic left ventricular volume, showed a trend but had an inconclusive association with Vit C. Therefore, it seems reasonable that these beneficial effects could be further enhanced by the association with other antioxidant agents. Indeed, the complexity and the multifactorial nature of the mechanism of injury occurring in AMI demands multitarget agents to reach an enhancement of the expected cardioprotection, a paradigm needing to be demonstrated. The present review provides data supporting the view that an intravenous infusion containing combined safe antioxidants could be a suitable strategy to reduce cardiac injury, thus improving the clinical outcome, life quality, and life expectancy of patients subjected to PCI following AMI.

Polymer Conjugation of Docosahexaenoic Acid Potentiates Cardioprotective Therapy in Preclinical Models of Myocardial Ischemia/Reperfusion Injury

While coronary angioplasty represents an effective treatment option following acute myocardial infarction, the reperfusion of the occluded coronary artery can prompt ischemia-reperfusion (I/R) injury that significantly impacts patient outcomes. As ω-3 polyunsaturated fatty acids (PUFAs) have proven, yet limited cardioprotective abilities, an optimized polymer-conjugation approach is reported that improves PUFAs bioavailability to enhance cardioprotection and recovery in animal models of I/R-induced injury. Poly-l-glutamic acid (PGA) conjugation improves the solubility and stability of di-docosahexaenoic acid (diDHA) under physiological conditions and protects rat neonatal ventricular myocytes from I/R injury by reducing apoptosis, attenuating autophagy, inhibiting reactive oxygen species generation, and restoring mitochondrial membrane potential. Enhanced protective abilities are associated with optimized diDHA loading and evidence is provided for the inherent cardioprotective potential of PGA itself. Pretreatment with PGA-diDHA before reperfusion in a small animal I/R model provides for cardioprotection and limits area at risk (AAR). Furthermore, the preliminary findings suggest that PGA-diDHA administration in a swine I/R model may provide cardioprotection, limit edema and decrease AAR. Overall, the evaluation of PGA-diDHA in relevant preclinical models provides evidence for the potential of polymer-conjugated PUFAs in the mitigation of I/R injury associated with coronary angioplasty.

Targeting Ferroptosis against Ischemia/Reperfusion Cardiac Injury

Ischemic heart disease is a leading cause of death worldwide. Primarily, ischemia causes decreased oxygen supply, resulting in damage of the cardiac tissue. Naturally, reoxygenation has been recognized as the treatment of choice to recover blood flow through primary percutaneous coronary intervention. This treatment is the gold standard therapy to restore blood flow, but paradoxically it can also induce tissue injury. A number of different studies in animal models of acute myocardial infarction (AMI) suggest that ischemia-reperfusion injury (IRI) accounts for up to 50% of the final myocardial infarct size. Oxidative stress plays a critical role in the pathological process. Iron is an essential mineral required for a variety of vital biological functions but also has potentially toxic effects. A detrimental process induced by free iron is ferroptosis, a non-apoptotic type of programmed cell death. Accordingly, efforts to prevent ferroptosis in pathological settings have focused on the use of radical trapping antioxidants (RTAs), such as liproxstatin-1 (Lip-1). Hence, it is necessary to develop novel strategies to prevent cardiac IRI, thus improving the clinical outcome in patients with ischemic heart disease. The present review analyses the role of ferroptosis inhibition to prevent heart IRI, with special reference to Lip-1 as a promising drug in this clinicopathological context.

Role of Muscle-Specific Histone Methyltransferase (Smyd1) in Exercise-Induced Cardioprotection against Pathological Remodeling after Myocardial Infarction

Pathological remodeling is the main detrimental complication after myocardial infarction (MI). Overproduction of reactive oxygen species (ROS) in infarcted myocardium may contribute to this process. Adequate exercise training after MI may reduce oxidative stress-induced cardiac tissue damage and remodeling. SET and MYND domain containing 1 (Smyd1) is a muscle-specific histone methyltransferase which is upregulated by resistance training, may strengthen sarcomere assembly and myofiber folding, and may promote skeletal muscles growth and hypertrophy. However, it remains elusive if Smyd1 has similar functions in post-MI cardiac muscle and participates in exercise-induced cardioprotection. Accordingly, we investigated the effects of interval treadmill exercise on cardiac function, ROS generation, Smyd1 expression, and sarcomere assembly of F-actin in normal and infarcted hearts. Adult male rats were randomly divided into five groups (n = 10/group): control (C), exercise alone (EX), sham-operated (S), MI induced by permanent ligation of left anterior descending coronary artery (MI), and MI with interval exercise training (MI + EX). Exercise training significantly improved post-MI cardiac function and sarcomere assembly of F-actin. The cardioprotective effects were associated with increased Smyd1, Trx1, cTnI, and α-actinin expression as well as upregulated ratio of phosphorylated AMP-activated protein kinase (AMPK)/AMPK, whereas Hsp90, MuRF1, brain natriuretic peptide (BNP) expression, ROS generation, and myocardial fibrosis were attenuated. The improved post-MI cardiac function was associated with increased Smyd1 expression. In cultured H9C2 cardiomyoblasts, in vitro treatment with H₂O₂ (50 µmol/L) or AMP-activated protein kinase (AMPK) agonist (AICAR, 1 mmol/L) or their combination for 4 h simulated the effects of exercise on levels of ROS and Smyd1. In conclusion, we demonstrated a novel role of Smyd1 in association with post-MI exercise-induced cardioprotection. The moderate level of ROS-induced upregulation of Smyd1 may be an important target for modulating post-MI cardiac function and remodeling.

The Anti-Inflammatory and Antioxidant Properties of n-3 PUFAs: Their Role in Cardiovascular Protection

Polyunsaturated fatty acids (n-3 PUFAs) are long-chain polyunsaturated fatty acids with 18, 20 or 22 carbon atoms, which have been found able to counteract cardiovascular diseases. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in particular, have been found to produce both vaso- and cardio-protective response via modulation of membrane phospholipids thereby improving cardiac mitochondrial functions and energy production. However, antioxidant properties of n-3 PUFAs, along with their anti-inflammatory effect in both blood vessels and cardiac cells, seem to exert beneficial effects in cardiovascular impairment. In fact, dietary supplementation with n-3 PUFAs has been demonstrated to reduce oxidative stress-related mitochondrial dysfunction and endothelial cell apoptosis, an effect occurring via an increased activity of endogenous antioxidant enzymes. On the other hand, n-3 PUFAs have been shown to counteract the release of pro-inflammatory cytokines in both vascular tissues and in the myocardium, thereby restoring vascular reactivity and myocardial performance. Here we summarize the molecular mechanisms underlying the anti-oxidant and anti-inflammatory effect of n-3 PUFAs in vascular and cardiac tissues and their implication in the prevention and treatment of cardiovascular disease.

Vitamin C for Cardiac Protection during Percutaneous Coronary Intervention: A Systematic Review of Randomized Controlled Trials

Percutaneous coronary intervention (PCI) is the preferred treatment for acute coronary syndrome (ACS) secondary to atherosclerotic coronary artery disease. This nonsurgical procedure is also used for selective patients with stable angina. Although the procedure is essential for restoring blood flow, reperfusion can increase oxidative stress as a side effect. We address whether intravenous infusion of vitamin C (VC) prior to PCI provides a benefit for cardioprotection. A total of eight randomized controlled trials (RCT) reported in the literature were selected from 371 publications through systematic literature searches in six electronic databases. The data of VC effect on cardiac injury biomarkers and cardiac function were extracted from these trials adding up to a total of 1185 patients. VC administration reduced cardiac injury as measured by troponin and CK-MB elevations, along with increased antioxidant reservoir, reduced reactive oxygen species (ROS) and decreased inflammatory markers. Improvement of the left ventricular ejection fraction (LVEF) and telediastolic left ventricular volume (TLVV) showed a trend but inconclusive association with VC. Intravenous infusion of VC before PCI may serve as an effective method for cardioprotection against reperfusion injury.

Perspective: Methionine Restriction-Induced Longevity-A Possible Role for Inhibiting the Synthesis of Bacterial Quorum Sensing Molecules

Methionine restriction (MR) extends lifespans in multiple species through mechanisms that include enhanced oxidative stress resistance and inhibition of insulin/insulin-like growth factor I (IGF-I) signaling. Methionine and S-adenosylmethionine (SAM) are the essential precursors of bacterial quorum sensing (QS) molecules, and therefore, MR might also affect bacterial communication to prevent enteric bacterial infection as well as chronic inflammation, which contributes to lifespan prolongation. Here, we discuss the influence of MR on oxidative stress resistance and inhibition of insulin/IGF-I cell signaling and further propose a potential mechanism involving bacterial QS inhibition for lifespan extension. Unraveling the connection between MR and inhibition of QS provides new strategies for combating infectious diseases, resulting in enriched understanding of MR-induced lifespan extension.

Preoperative Ascorbic Acid Levels in Proximal Femur Fracture Patients Have No Postoperative Clinical Impact, While Ascorbic Acid Levels upon Discharge Have a Major Effect on Postoperative Outcome

Proximal femur fractures show a high prevalence in elderly patients and are associated with an elevated risk of multimorbidity and early mortality. Recovery is impaired by malnutrition and oxidative stress, which is affected by antioxidants such as ascorbic acid (AA). This study monitored AA levels during hospitalization of patients with a proximal femur to investigate the influence of AA status to the clinical outcome. AA levels of 25 elderly patients with a proximal femur fracture were measured during hospitalization using high performance liquid chromatography. Plasma samples were collected preoperatively, on the first day after surgery, on the third day after surgery and on the day of discharge. Nutritional Risk Screening 2002 (NRS) and Mini Nutritional Assessment (MNA) were assessed to evaluate the nutritional status. In patients with proximal femoral fractures, preoperative AA concentrations were significantly lower compared to elderly patients without an acute fracture. A significant decrease of 33.8% in AA plasma level was measured on the day after surgery with a significant recovery up to the time of discharge. The preoperative AA status did not have any significant effect on clinical outcome. However, inadequate AA levels (<50 µmol/L) upon discharge significantly increased the incidence and the severity of postoperative complications. These results indicate that the AA status upon discharge has a greater impact on clinical outcome than assumed, and therefore, AA supplementation during hospitalization should be considered.

The Neuroprotective Effects of Astaxanthin: Therapeutic Targets and Clinical Perspective

As the leading causes of human disability and mortality, neurological diseases affect millions of people worldwide and are on the rise. Although the general roles of several signaling pathways in the pathogenesis of neurodegenerative disorders have so far been identified, the exact pathophysiology of neuronal disorders and their effective treatments have not yet been precisely elucidated. This requires multi-target treatments, which should simultaneously attenuate neuronal inflammation, oxidative stress, and apoptosis. In this regard, astaxanthin (AST) has gained growing interest as a multi-target pharmacological agent against neurological disorders including Parkinson’s disease (PD), Alzheimer’s disease (AD), brain and spinal cord injuries, neuropathic pain (NP), aging, depression, and autism. The present review highlights the neuroprotective effects of AST mainly based on its anti-inflammatory, antioxidative, and anti-apoptotic properties that underlies its pharmacological mechanisms of action to tackle neurodegeneration. The need to develop novel AST delivery systems, including nanoformulations, targeted therapy, and beyond, is also considered.

Plasma Malondialdehyde and Risk of New-Onset Diabetes after Transplantation in Renal Transplant Recipients: A Prospective Cohort Study

New-onset diabetes after transplantation (NODAT) is a frequent complication in renal transplant recipients (RTR). Although oxidative stress has been associated with diabetes mellitus, data regarding NODAT are limited. We aimed to prospectively investigate the long-term association between the oxidative stress biomarker malondialdehyde (measured by high-performance liquid chromatography) and NODAT in an extensively phenotyped cohort of non-diabetic RTR with a functioning graft ≥1 year. We included 516 RTR (51 ± 13 years-old, 57% male). Median plasma malondialdehyde (MDA) was 2.55 (IQR, 1.92-3.66) µmol/L. During a median follow-up of 5.3 (IQR, 4.6-6.0) years, 56 (11%) RTR developed NODAT. In Cox proportional-hazards regression analyses, MDA was inversely associated with NODAT, independent of immunosuppressive therapy, transplant-specific covariates, lifestyle, inflammation, and metabolism parameters (HR, 0.55; 95% CI, 0.36-0.83 per 1-SD increase; p < 0.01). Dietary antioxidants intake (e.g., vitamin E, α-lipoic acid, and linoleic acid) were effect-modifiers of the association between MDA and NODAT, with particularly strong inverse associations within the subgroup of RTR with relatively higher dietary antioxidants intake. In conclusion, plasma MDA concentration is inversely and independently associated with long-term risk of NODAT in RTR. Our findings support a potential underrecognized role of oxidative stress in post-transplantation glucose homeostasis.

Potential Role of Vitamin C Intracoronary Administration in Preventing Cardiac Injury After Primary Percutaneous Coronary Intervention in Patients with ST-Elevation Myocardial Infarction

Objective:

The aim of the present study was to determine the effects of intravenous (IV) and intracoronary administration of Vitamin C on the incidence of periprocedural myocardial injury in patients undergoing primary percutaneous coronary intervention (PCI).

Methods:

In this prospective, double-blind, randomized clinical trial, that was conducted in Tehran Heart Center, Iran, between October 2016 and March 2017, 252 patients undergoing primary PCI were enrolled to receive either 3 g of IV Vitamin C before PCI and 100 mg of intracoronary Vitamin C during PCI in addition to the routine treatment (n = 126) or just the routine treatment (n = 126). Cardiac biomarkers were measured before and then 6 and 12 h postprocedurally. We determined the occurrence of contrast-induced acute kidney injury (CI-AKI), according to the levels of serum creatinine, neutrophil gelatinase-associated lipocalin, and platelet activation biomarker (P-selectin) in a subset of 119 patients before and 6 h after PCI.

Findings:

In the patients who received Vitamin C, the serum levels of troponin T after 12 h and creatine kinase-MB after 6 h were significantly lower than those in the placebo group (P = 0.003 andP = 0.00, respectively). CI-AKI occurred in 6 (4.7%) patients in the study group and 8 (6.3%) patients in the control group; there was no significant reduction in CI-AKI in the study group. In addition, the two groups were statically similar as regards the changes in the level of P-selectin.

Conclusion:

In primary PCI patients, the prophylactic use of IV and intracoronary Vitamin C can confer additional clinical benefits such as cardioprotection.

Myocardial reperfusion injury and oxidative stress: Therapeutic opportunities

Acute myocardial infarction (AMI) is the leading cause of death worldwide. Its associated mortality, morbidity and complications have significantly decreased with the development of interventional cardiology and percutaneous coronary angioplasty (PCA) treatment, which quickly and effectively restore the blood flow to the area previously subjected to ischemia. Paradoxically, the restoration of blood flow to the ischemic zone leads to a massive production of reactive oxygen species (ROS) which generate rapid and severe damage to biomolecules, generating a phenomenon called myocardial reperfusion injury (MRI). In the clinical setting, MRI is associated with multiple complications such as lethal reperfusion, no-reflow, myocardial stunning, and reperfusion arrhythmias. Despite significant advances in the understanding of the mechanisms accounting for the myocardial ischemia reperfusion injury, it remains an unsolved problem. Although promising results have been obtained in experimental studies (mainly in animal models), these benefits have not been translated into clinical settings. Thus, clinical trials have failed to find benefits from any therapy to prevent MRI. There is major evidence with respect to the contribution of oxidative stress to MRI in cardiovascular diseases. The lack of consistency between basic studies and clinical trials is not solely based on the diversity inherent in epidemiology but is also a result of the methodological weaknesses of some studies. It is quite possible that pharmacological issues, such as doses, active ingredients, bioavailability, routes of administration, co-therapies, startup time of the drug intervention, and its continuity may also have some responsibility for the lack of consistency between different studies. Furthermore, the administration of high ascorbate doses prior to reperfusion appears to be a safe and rational therapy against the development of oxidative damage associated with myocardial reperfusion. In addition, the association with N-acetylcysteine (a glutathione donor) and deferoxamine (an iron chelator) could improve the antioxidant cardioprotection by ascorbate, making it even more effective in preventing myocardial reperfusion damage associated with PCA following AMI.

Vitamin C to Improve Organ Dysfunction in Cardiac Surgery Patients-Review and Pragmatic Approach

The pleiotropic biochemical and antioxidant functions of vitamin C have sparked recent interest in its application in intensive care. Vitamin C protects important organ systems (cardiovascular, neurologic and renal systems) during inflammation and oxidative stress. It also influences coagulation and inflammation; its application might prevent organ damage. The current evidence of vitamin C's effect on pathophysiological reactions during various acute stress events (such as sepsis, shock, trauma, burn and ischemia-reperfusion injury) questions whether the application of vitamin C might be especially beneficial for cardiac surgery patients who are routinely exposed to ischemia/reperfusion and subsequent inflammation, systematically affecting different organ systems. This review covers current knowledge about the role of vitamin C in cardiac surgery patients with focus on its influence on organ dysfunctions. The relationships between vitamin C and clinical health outcomes are reviewed with special emphasis on its application in cardiac surgery. Additionally, this review pragmatically discusses evidence on the administration of vitamin C in every day clinical practice, tackling the issues of safety, monitoring, dosage, and appropriate application strategy.

Effect of Water-Soluble Echinochrome Analog on Arrhythmia Severity in Experimental Model of Acute Myocardial Ischemia

The effects of therapeutic or preventive-therapeutic administration of water-soluble echinochrome analog U-441 on arrhythmia severity assessed by a set of myocardial spatio-temporal depolarization and repolarization parameters were examined on the model of acute myocardial ischemia in cats. Coronary occlusion increased activation time and decreased repolarization time in the ischemic zone; in addition, it increased both global and borderline (local) dispersions of repolarization. The linear regression model showed that only activation time values measured at the initial state and at termination of occlusion were associated with total arrhythmia score during ischemia (regression coefficient β=0.338, 95%CI=0.074-0.602, p=0.015 and β=0.720, 95%CI=0.323-1.117, p=0.001, respectively). The study revealed no association between administration of echinochrome analog U-441 and arrhythmia severity.

Essential role for smooth muscle cell stromal interaction molecule-1 in myocardial infarction

OBJECTIVES

Stromal interacting molecule-1 (STIM1) plays a role in coordinating calcium signaling in different cell types. The increase or deletion of STIM1 expression in cardiomyocyte causes cardiac complication. Moreover, the deletion of STIM1 in endothelial cell causes vascular endothelial dysfunction. However, the disruption of STIM1 in smooth muscle cells (SMC) has no effect on endothelial function but protects vascular function when mice are infused with angiotensin-II. Nevertheless, the role of SMC-STIM1 in acute and chronic myocardial infarction (MI) induced by acute ischemia-reperfusion injury and permanent coronary artery occlusion is unknown.

METHODS AND RESULTS

Stim1 were generated and crossed into the SM22α-Cre backgrounds. SM22α-Cre causes deletion of STIM1 floxed genes in adult SMC (Stim1). Control and Stim1 mice were subjected to acute ischemia-reperfusion injury. Hearts were then harvested and incubated with triphenyltetrazolium chloride to determine the infarct size. In control mice which are subjected to ischemia-reperfusion, the heart developed a significant infarct associated with an increase in STIM1 expression. Interestingly, the infarct size was substantially reduced in Stim1 mice. The protection in Stim1 mice against ischemia-reperfusion injury involves the modulation of endoplasmic reticulum stress, apoptosis, oxidative stress, protein kinase B, and mitogen-activated protein (MAP) kinase (ERK1/2 and p38) signaling, and inflammation. Furthermore, in another model of chronic MI induced by permanent coronary artery occlusion, SMC-STIM1 disruption significantly reduced myocardial infarct size and improved cardiac function.

CONCLUSION

Our results provide new evidence that SMC-STIM1 disruption is a novel mechanism that protects the heart from MI through reduction of endoplasmic reticulum stress, oxidative stress, MAP-Kinase, apoptosis, and inflammation.

Propofol attenuates H2O2-induced oxidative stress and apoptosis via the mitochondria- and ER-medicated pathways in neonatal rat cardiomyocytes

Previous studies have shown that propofol, an intravenous anesthetic commonly used in clinical practice, protects the myocardium from injury. Mitochondria- and endoplasmic reticulum (ER)-mediated oxidative stress and apoptosis are two important signaling pathways involved in myocardial injury and protection. The present study aimed to test the hypothesis that propofol could exert a cardio-protective effect via the above two pathways. Cultured neonatal rat cardiomyocytes were treated with culture medium (control group), H₂O₂ at 500 μM (H₂O₂ group), propofol at 50 μM (propofol group), and H₂O₂ plus propofol (H₂O₂ + propofol group), respectively. The oxidative stress, mitochondrial membrane potential (ΔΨm) and apoptosis of the cardiomyocytes were evaluated by a series of assays including ELISA, flow cytometry, immunofluorescence microscopy and Western blotting. Propofol significantly suppressed the H₂O₂-induced elevations in the activities of caspases 3, 8, 9 and 12, the ratio of Bax/Bcl-2, and cell apoptosis. Propofol also inhibited the H₂O₂-induced reactive oxygen species (ROS) generation, lactic dehydrogenase (LDH) release and mitochondrial transmembrane potential (ΔΨm) depolarization, and restored the H₂O₂-induced reductions of glutathione (GSH) and superoxide dismutase (SOD). In addition, propofol decreased the expressions of glucose-regulated protein 78 kDa (Grp78) and inositol-requiring enzyme 1α (IRE1α), two important signaling molecules in the ER-mediated apoptosis pathway. Propofol protects cardiomyocytes from H₂O₂-induced injury by inhibiting the mitochondria- and ER-mediated apoptosis signaling pathways.

Serum ω-3 Polyunsaturated Fatty Acids and Potential Influence Factors in Elderly Patients with Multiple Cardiovascular Risk Factors

Recent clinical trials failed to demonstrate that ω-3 polyunsaturated fatty acid (PUFA) supplement reduced cardiovascular events, which contradicted previous evidence. However, serum ω-3 PUFA concentrations of participants remained unclear in those studies. We aimed to investigate the definite relationship between serum concentrations of ω-3 PUFAs and coronary artery disease (CAD), and to explore the potential influence factors of ω-3 PUFAs. We selected Chinese in-patients (n = 460) with multiple cardiovascular risk factors or an established diagnosis of CAD. Serum ω-3 PUFAs, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were measured by liquid chromatography mass spectrometry. Serum concentrations of ω-3 PUFAs in CAD patients were lower than that in patients with cardiovascular risk factors. Furthermore, high serum DHA concentration was an independent protective factor of CAD after adjustment for confounding factors (OR: 0.52, p = 0.014). Alcohol intake (p = 0.036) and proton pump inhibitor (PPI) usage (p = 0.027) were associated with a decreased serum ω-3 PUFA concentration. We conclude that serum concentrations of ω-3 PUFAs may associate with a decreased CAD proportion, and DHA may serve as a protective factor of CAD. Serum ω-3 PUFA concentrations may be reduced by alcohol intake and certain drugs like PPIs.

Oligomeric proanthocyanidins protect myocardium by mitigating left ventricular remodeling in isoproterenol-induced postmyocardial infarction

Extracellular matrix (ECM) remodeling is a major pathophysiological process during post-myocardial infarction (MI). The activation, differentiation, and proliferation of cardiac fibroblasts to myofibroblasts regulate the expression of ECM proteins. The signaling by bone morphogenetic protein (BMP-4), an extracellular ligand of the TGF-β family, has recently been identified as an essential pathway in regulating cardiovascular dysfunctions including myocardial fibrosis. Oligomeric proanthocyanidins (OPC) are well known for their cardioprotective activity. The primary aim of the study was to investigate BMP-4-mediated ECM turnover in cardiac fibrosis during isoproterenol-induced post-MI and its downregulation by OPC. Myocardial injury was evaluated by assaying serum markers LDH and CK. Oxidative stress and the enzymatic and nonenzymatic antioxidant levels were assessed to support the cardioprotective nature of OPC. The total collagen level was analyzed by measuring hydroxyproline levels. The ISO-induced group showed a significant decrease in the levels of antioxidants due to severe oxidative stress and increased expression of BMP-4 which reflects the increased expression of MMP 2 and 9 with a concomitant increase and deposition of fibrillary collagens type I and III responsible for the fibrotic scar formation as evidenced in the histological analysis.BMP-4 activation, thus, is strongly associated with cardiac fibrosis which was downregulated upon OPC supplementation. This study provides an evidence supporting the antifibrotic effect of OPC via regulation of BMP-4-mediated ECM turnover and also substantiates the remarkable antioxidant efficacy of OPC against isoproterenol induced severe oxidative stress and subsequent post-MI cardiac fibrosis.

Antioxidant Therapeutic Strategies for Cardiovascular Conditions Associated with Oxidative Stress

Oxidative stress (OS) refers to the imbalance between the generation of reactive oxygen species (ROS) and the ability to scavenge these ROS by endogenous antioxidant systems, where ROS overwhelms the antioxidant capacity. Excessive presence of ROS results in irreversible damage to cell membranes, DNA, and other cellular structures by oxidizing lipids, proteins, and nucleic acids. Oxidative stress plays a crucial role in the pathogenesis of cardiovascular diseases related to hypoxia, cardiotoxicity and ischemia-reperfusion. Here, we describe the participation of OS in the pathophysiology of cardiovascular conditions such as myocardial infarction, anthracycline cardiotoxicity and congenital heart disease. This review focuses on the different clinical events where redox factors and OS are related to cardiovascular pathophysiology, giving to support for novel pharmacological therapies such as omega 3 fatty acids, non-selective betablockers and microRNAs.

Bio-tea prevents membrane destabilization during Isoproterenol-induced myocardial injury

The present study was undertaken to determine the membrane-stabilizing effect of Bio-tea in the prevention of myocardial injury caused by isoproterenol in rats. The efficiency of Bio-tea pretreatment was compared against black tea pretreatment and the positive control (rats with isoproterenol-induced myocardial infarction) and negative control (normal control rats). For this purpose, biochemical analysis of the in vivo antioxidants (superoxide dismutase, catalase, and reduced glutathione), glycoprotein components (hexose, hexosamine, sialic acid, and fucose), lipids (total, ester and free cholesterol, triglycerides, free fatty acids, and phospholipids), and transmembrane protein activities (Na+/K+ ATPase, Ca2+ ATPase, and Mg2+ ATPase) was carried out along with the histological and ultrastructural study of the myocardial tissue. Induction of myocardial infarction using isoproterenol resulted in a significant decrease in tissue antioxidants and an increase in the levels of total, ester and free cholesterol, triglycerides, free fatty acids, and glycoprotein components in plasma and heart. The phospholipid content showed an increase in plasma and a simultaneous decrease in the heart tissue, while the Na+/K+ ATPase activity decreased and Ca2+ ATPase and Mg2+ ATPase activities increased, resulting in destabilization of the membranes. Pretreatment with Bio-tea was able to bring these components to near normal, indicating its reactive-oxygen-species-scavenging, lipid-lowering, membrane-stabilizing and glycoprotein-modulating effects and lending credibility to the regular use of Bio-tea.

Role of levothyroxine and vitamin E supplementation in the treatment of oxidative stress-induced injury and apoptosis of myocardial cells in hypothyroid rats

OBJECTIVE

To explore the underlying mechanism and treatment of myocardial injury caused by hypothyroidism, we evaluated oxidative stress in serum and myocardial tissue of hypothyroid rats. The effect of levothyroxine (LT4) replacement therapy and vitamin E (VitE) supplementation on oxidative stress-induced injury and apoptosis of myocardial tissue is examined.

METHODS

Male Sprague-Dawley rats were divided into five groups: normal control group, propylthiouracil group (PTU group), LT4 treatment group (PTU + LT4 group), vitamin E treatment group (PTU + VitE group), and combined treatment group (PTU + LT4 + VitE group). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) expression in serum and myocardium were determined. Myocardial apoptosis index (AI) in each group was determined by TUNEL assay.

RESULTS

SOD levels in serum were significantly increased in PTU + VitE and PTU + LT4 + Vit E groups, as compared to that in PTU and PTU + LT4 groups (P < 0.05). MDA levels in serum and myocardial tissue were significantly lower in PTU + LT4, PTU + VitE, and PTU + LT4 + VitE groups, as compared to that in the PTU group (P < 0.05). Myocardial apoptosis was significantly increased in PTU and PTU + VitE groups as compared to that in the normal control group (P < 0.05), while it was significantly lower in PTU + LT4 and PTU + LT4 + VitE groups, as compared to that in the PTU group (P < 0.05).

CONCLUSION

In this study, levothyroxine replacement therapy and vitamin E supplementation appeared to ameliorate myocardial apoptosis in hypothyroid rats, the mechanism of which appears to be related to improved thyroid function and reduced oxidative stress.

Effects of a novel ascorbate-based protocol on infarct size and ventricle function in acute myocardial infarction patients undergoing percutaneous coronary angioplasty

INTRODUCTION

This study was designed to test the hypothesis that high-dose ascorbate prior to reperfusion followed by low chronic oral doses ameliorate myocardial reperfusion injury (MRI) in acute myocardial infarction patients subjected to primary percutaneous coronary angioplasty (PCA).

MATERIAL AND METHODS

A randomized double-blind placebo-controlled and multicenter clinical trial was performed on acute myocardial infarction (AMI) patients who underwent PCA. Sodium ascorbate (320 mmol/l, n = 53) or placebo (n = 46) was infused 30 min prior to PCA. Blood samples were drawn at enrolment (M1), after balloon deflation (M2), 6-8 h after M2 (M3) and at discharge (M4). Total antioxidant capacity of plasma (ferric reducing ability of plasma - FRAP), erythrocyte reduced glutathione (GSH) and plasma ascorbate levels were determined in blood samples. Cardiac magnetic resonance (CMR) was performed at 7-15 days and 2-3 months following PCA. Ninety-nine patients were enrolled. In 67 patients, the first CMR was performed, and 40 patients completed follow-up.

RESULTS

The ascorbate group showed significantly higher ascorbate and FRAP levels and a decrease in the GSH levels at M2 and M3 (p < 0.05). There were no significant differences in the infarct size, indexed end-systolic volume and ejection fraction at both CMRs. There was a significant amelioration in the decreased ejection fraction between the first and second CMR in the ascorbate group (p < 0.05).

CONCLUSIONS

Ascorbate given prior to reperfusion did not show a significant difference in infarct size or ejection fraction. However, it improved the change in ejection fraction determined between 7-15 days and 2-3 months. This result hints at a possible functional effect of ascorbate to ameliorate MRI.

Sulforaphane improves oxidative status without attenuating the inflammatory response or cardiac impairment induced by ischemia–reperfusion in rats

Sulforaphane, a natural isothiocyanate, demonstrates cardioprotection associated with its capacity to stimulate endogenous antioxidants and to inhibit inflammation. The aim of this study was to investigate whether sulforaphane is capable of attenuating oxidative stress and inflammatory responses through the TLR4/MyD88/NFκB pathway, and thereby could modulate post-ischemic ventricular function in isolated rat hearts submitted to ischemia and reperfusion. Male Wistar rats received sulforaphane (10 mg·kg−1·day−1) or vehicle i.p. for 3 days. Global ischemia was performed using isolated hearts, 24 h after the last injection, by interruption of the perfusion flow. The protocol included a 20 min pre-ischemic period followed by 20 min of ischemia and a 20 min reperfusion. Although no changes in mechanical function were observed, sulforaphane induced a significant increase in superoxide dismutase and heme oxygenase-1 expression (both 66%) and significantly reduced reactive oxygen species levels (7%). No differences were observed for catalase and glutathione peroxidase expression or their activities, nor for thioredoxin reductase, glutaredoxin reductase and glutathione-S-transferase. No differences were found in lipid peroxidation or TLR4, MyD88, and NF-κB expression. In conclusion, although sulforaphane was able to stimulate endogenous antioxidants modestly, this result did not impact inflammatory signaling or cardiac function of hearts submitted to ischemia and reperfusion.

Pharmacological models and approaches for pathophysiological conditions associated with hypoxia and oxidative stress

Hypoxia is the failure of oxygenation at the tissue level, where the reduced oxygen delivered is not enough to satisfy tissue demands. Metabolic depression is the physiological adaptation associated with reduced oxygen consumption, which evidently does not cause any harm to organs that are exposed to acute and short hypoxic insults. Oxidative stress (OS) refers to the imbalance between the generation of reactive oxygen species (ROS) and the ability of endogenous antioxidant systems to scavenge ROS, where ROS overwhelms the antioxidant capacity. Oxidative stress plays a crucial role in the pathogenesis of diseases related to hypoxia during intrauterine development and postnatal life. Thus, excessive ROS are implicated in the irreversible damage to cell membranes, DNA, and other cellular structures by oxidizing lipids, proteins, and nucleic acids. Here, we describe several pathophysiological conditions and in vivo and ex vivo models developed for the study of hypoxic and oxidative stress injury. We reviewed existing literature on the responses to hypoxia and oxidative stress of the cardiovascular, renal, reproductive, and central nervous systems, and discussed paradigms of chronic and intermittent hypobaric hypoxia. This systematic review is a critical analysis of the advantages in the application of some experimental strategies and their contributions leading to novel pharmacological therapies.

Involvement of Glycogen Synthase Kinase-3β and Oxidation Status in the Loss of Cardioprotection by Postconditioning in Chronic Diabetic Male Rats

PURPOSE

Diabetes mellitus as a main risk-factor of ischemic heart disease may interfere with postconditioning'scardioprotective effects. This study aimed to investigate the involvement of glycogen synthase kinase-3β (GSK-3β) and oxidation status in chronic diabetes-induced loss of cardioprotective effect of ischemic-postconditioning (IPostC) in Wistar rats.

METHODS

After 8 weeks of induction of diabetes by streptozotocin (50mg/kg), hearts of control and diabetic rats were isolated and mounted on a constant-pressure Langendorff system. All hearts were subjected to 30min regional ischemia followed by 60min reperfusion (by occluding and re-opening of left anterior descending coronary artery, respectively). IPostC was applied immediately at the onset of reperfusion. At the end of reperfusion, the infarct size of myocardium was measured via computerized planimetry. Myocardial contents of malondealdehyde and glutathione as indices of oxidative status were assayed spectrophotometrically and the total and phosphorylated forms of myocardial GSK-3β were quantified through western blotting.

RESULTS

IPostC reduced the infarct size of control hearts from 41±2.9% to 28±1.9% (P<0.05), whereas it could not induce significant changes in infarct size of diabetic animals (35±1.8% vs. 39±3.1%). IPostC-induced reduction in malondealdehyde and elevation in glutathione contents were significant only in control not in diabetic hearts. The total forms of GSK-3β were similar in all groups; however, the phosphorylation of GSK-3β (at Ser9) by IPostC was greater in control hearts than diabetics (P<0.01).

CONCLUSION

The failure of cardioprotection by IPostC in diabetic hearts may be attributed to the loss of phosphorylation of GSK-3β and thereby increase in oxidative stress in diabetic states.

Non-targeted metabolomics analysis of cardiac Muscle Ring Finger-1 (MuRF1), MuRF2, and MuRF3 in vivo reveals novel and redundant metabolic changes

The muscle-specific ubiquitin ligases MuRF1, MuRF2, MuRF3 have been reported to have overlapping substrate specificities, interacting with each other as well as proteins involved in metabolism and cardiac function. In the heart, all three MuRF family proteins have proven critical to cardiac responses to ischemia and heart failure. The non-targeted metabolomics analysis of MuRF1-/-, MuRF2-/-, and MuRF3-/- hearts was initiated to investigate the hypothesis that MuRF1, MuRF2, and MuRF3 have a similarly altered metabolome, representing alterations in overlapping metabolic processes. Ventricular tissue was flash frozen and quantitatively analyzed by GC/MS using a library built upon the Fiehn GC/MS Metabolomics RTL Library. Non-targeted metabolomic analysis identified significant differences (via VIP statistical analysis) in taurine, myoinositol, and stearic acid for the three MuRF-/- phenotypes relative to their matched controls. Moreover, pathway enrichment analysis demonstrated that MuRF1-/- had significant changes in metabolite(s) involved in taurine metabolism and primary acid biosynthesis while MuRF2-/- had changes associated with ascorbic acid/aldarate metabolism (via VIP and t-test analysis vs. sibling-matched wildtype controls). By identifying the functional metabolic consequences of MuRF1, MuRF2, and MuRF3 in the intact heart, non-targeted metabolomics analysis discovered common pathways functionally affected by cardiac MuRF family proteins in vivo. These novel metabolomics findings will aid in guiding the molecular studies delineating the mechanisms that MuRF family proteins regulate metabolic pathways. Understanding these mechanism is an important key to understanding MuRF family proteins' protective effects on the heart during cardiac disease.