Oxidative Stress Evaluation in Ischemia Reperfusion Models: Characteristics, Limits and Perspectives

Research on the mechanism of the anti-myocardial infarction effect of the Qiliqiangxin capsule on heart failure rats via nontargeted metabolomics and lipidomics

BACKGROUND

Qi Li Qiang Xin (QLQX) capsule has a solid theoretical basis and clinical efficacy in the treatment of chronic heart failure; however, the underlying mechanisms remain obscure. This study was designed to determine the effect of the QLQX on the treatment of heart failure and delineate the underlying mechanisms via a nontargeted metabolomics and lipidomics approach.

METHODS

A rat model of heart failure after myocardial infarction (MI) was established via permanent ligation of the anterior descending branch of the left coronary artery. The rats were then randomly divided into the SHAM group, the MI group, the QLQX group (1.3 g/kg/day), and the VAL (valsartan) group (80 mg/kg/day). Cardiac function was measured via echocardiography. The levels of serum NT-proBNP and hs-cTn-I were detected via ELISA. H&E staining and Masson's trichrome staining were used to observe cardiac morphology and myocardial fibrosis. Using the UPLC-QTOF/MS method, metabolomics and lipidomics analyses were performed on the plasma of the rats in each group to identify biomarkers and potential amino acid and lipid therapy mechanisms for heart failure after QLQX administration in rats with heart failure.

RESULTS

QLQX capsule improved the heart f unction of rats with heart failure after myocardial infarction by increasing the LVEF and LVFS, decreasing the LVIDd and LVIDs. QLQX capsule reduce the levels of NT-proBNP and hs-cTn-I, which are markers of heart failure, and improve the myocardial infarction area and degree of myocardial fibrosis. In addition, in the metabolomics analysis, a total of 17 plasma metabolites were significantly different between heart failure rats and normal rats, all of which recovered significantly after QLQX treatment. These metabolites mainly participate in the biosynthesis of unsaturated fatty acids; valine, leucine and isoleucine biosynthesis; phenylalanine, tyrosine and tryptophan biosynthesis; and glycerophospholipid metabolism. Lipid analysis revealed that FA18:2, FA18:3, FA20:5, and FA22:6 in the QLQX group were significantly altered (P < 0.01). The peak area contents of FA18:2, FA18:3, FA20:5, and FA22:6 in the sham surgery group and model group also significantly decreased (P < 0.05).

CONCLUSION

This study elucidates the therapeutic effect of QLQX on heart failure rats and elucidates its potential mechanisms, which are related mainly to the regulation of amino acid and lipid metabolism in heart failure rats through metabolomics and lipidomics experiments.

Emerging mechanisms of lipid peroxidation in regulated cell death and its physiological implications

Regulated cell death (RCD) refers to the form of cell death that can be regulated by various biomacromolecules. Each cell death modalities have their distinct morphological changes and molecular mechanisms. However, intense evidences suggest that lipid peroxidation can be the common feature that initiates and propagates the cell death. Excessive lipid peroxidation alters the property of membrane and further damage the proteins and nucleic acids, which is implicated in various human pathologies. Here, we firstly review the classical chain process of lipid peroxidation, and further clarify the current understanding of the myriad roles and molecular mechanisms of lipid peroxidation in various RCD types. We also discuss how lipid peroxidation involves in diseases and how such intimate association between lipid peroxidation-driven cell death and diseases can be leveraged to develop rational therapeutic strategies.

Polyphenols for stroke therapy: the role of oxidative stress regulation

Stroke is associated with a high incidence and disability rate, which seriously endangers human health. Oxidative stress (OS) plays a crucial role in the underlying pathologic progression of cerebral damage in stroke. Emerging experimental studies suggest that polyphenols have antioxidant potential and express protective effects after different types of strokes, but no breakthrough has been achieved in clinical studies. Nanomaterials, due to small characteristic sizes, can be used to deliver drugs, and have shown excellent performance in the treatment of various diseases. The drug delivery capability of nanomaterials has significant implications for the clinical translation and application of polyphenols. This comprehensive review introduces the mechanism of oxidative stress in stroke, and also summarizes the antioxidant effects of polyphenols on reactive oxygen species generation and oxidative stress after stroke. Also, the application characteristics and research progress of nanomaterials in the treatment of stroke with antioxidants are presented.

Neobavaisoflavone Protects H9c2 Cells Against H2O2-Induced Mitochondrial Dysfunction Through ALOX15/PGC1-α Axis

Neobavaisoflavone (NBIF) is a natural antioxidant that has a variety of pharmacological activities. To investigate the effects of NBIF on oxidative stress-induced myocardial injury, H9c2 cells were treated with H2O2. Cell counting kit-8 was used to detect cell viability. Intracellular as well as lipid radicals were detected. To measure mitochondrial function, tetramethylrhodamine ethyl ester was used to detect mitochondrial membrane potential. 12- and 15-hydroxyeicosatetraenoic acids (HETE) were measured by LC-MS/MS. ALOX15, which is the upstream protein of 12-, 15-HETE, was also measured by using western blot analysis. The results showed that H2O2 induced lipid peroxidation in cardiomyocytes and caused mitochondrial dysfunction which was relieved by NBIF treatment. Besides, H2O2 significantly increased the production of 12-HETE and 15-HETE and upregulated the expression of ALOX15 while PGC-1α was downregulated and triggered the release of cytochrome c. The treatment of NBIF decreased the expression of ALOX15 and inhibited the activation of caspase-3. NBIF protected mitochondrial membrane integrity through increasing PGC-1α and Nrf1. Our results indicated that NBIF could protect cardiomyocytes against H2O2-induced mitochondrial dysfunction via ALOX15/PGC-1α axis.

Treatment of Acute and Long-COVID, Diabetes, Myocardial Infarction, and Alzheimer's Disease: The Potential Role of a Novel Nano-Compound-The Transdermal Glutathione-Cyclodextrin Complex

Oxidative stress (OS) occurs from excessive reactive oxygen species or a deficiency of antioxidants-primarily endogenous glutathione (GSH). There are many illnesses, from acute and post-COVID-19, diabetes, myocardial infarction to Alzheimer's disease, that are associated with OS. These dissimilar illnesses are, in order, viral infections, metabolic disorders, ischemic events, and neurodegenerative disorders. Evidence is presented that in many illnesses, (1) OS is an early initiator and significant promotor of their progressive pathophysiologic processes, (2) early reduction of OS may prevent later serious and irreversible complications, (3) GSH deficiency is associated with OS, (4) GSH can likely reduce OS and restore adaptive physiology, (5) effective administration of GSH can be accomplished with a novel nano-product, the GSH/cyclodextrin (GC) complex. OS is an overlooked pathological process of many illnesses. Significantly, with the GSH/cyclodextrin (GC) complex, therapeutic administration of GSH is now available to reduce OS. Finally, rigorous prospective studies are needed to confirm the efficacy of this therapeutic approach.

Oxidative stress, defective proteostasis and immunometabolic complications in critically ill patients

Oxidative stress (OS) develops in critically ill patients as a metabolic consequence of the immunoinflammatory and degenerative processes of the tissues. These induce increased and/or dysregulated fluxes of reactive species enhancing their pro-oxidant activity and toxicity. At the same time, OS sustains its own inflammatory and immunometabolic pathogenesis, leading to a pervasive and vitious cycle of events that contribute to defective immunity, organ dysfunction and poor prognosis. Protein damage is a key player of these OS effects; it generates increased levels of protein oxidation products and misfolded proteins in both the cellular and extracellular environment, and contributes to forms DAMPs and other proteinaceous material to be removed by endocytosis and proteostasis processes of different cell types, as endothelial cells, tissue resident monocytes-macrophages and peripheral immune cells. An excess of OS and protein damage in critical illness can overwhelm such cellular processes ultimately interfering with systemic proteostasis, and consequently with innate immunity and cell death pathways of the tissues thus sustaining organ dysfunction mechanisms. Extracorporeal therapies based on biocompatible/bioactive membranes and new adsorption techniques may hold some potential in reducing the impact of OS on the defective proteostasis of patients with critical illness. These can help neutralizing reactive and toxic species, also removing solutes in a wide spectrum of molecular weights thus improving proteostasis and its immunometabolic corelates. Pharmacological therapy is also moving steps forward which could help to enhance the efficacy of extracorporeal treatments. This narrative review article explores the aspects behind the origin and pathogenic role of OS in intensive care and critically ill patients, with a focus on protein damage as a cause of impaired systemic proteostasis and immune dysfunction in critical illness.

Hypoxia-preconditioned WJ-MSC spheroid-derived exosomes delivering miR-210 for renal cell restoration in hypoxia-reoxygenation injury

BACKGROUND

Recent advancements in mesenchymal stem cell (MSC) technology have paved the way for innovative treatment options for various diseases. These stem cells play a crucial role in tissue regeneration and repair, releasing local anti-inflammatory and healing signals. However, challenges such as homing issues and tumorigenicity have led to exploring MSC-exosomes as a promising alternative. MSC-exosomes have shown therapeutic potential in conditions like renal ischemia-reperfusion injury, but low production yields hinder their clinical use.

METHODS

To address this limitation, we examined hypoxic preconditioning of Wharton jelly-derived MSCs (WJ-MSCs) 3D-cultured in spheroids on isolated exosome yields and miR-21 expression. We then evaluated their capacity to load miR-210 into HEK-293 cells and mitigate ROS production, consequently enhancing their survival and migration under hypoxia-reoxygenation conditions.

RESULTS

MiR-210 overexpression was significantly induced by optimized culture and preconditioning conditions, which also improved the production yield of exosomes from grown MSCs. The exosomes enriched with miR-210 demonstrated a protective effect by improving survival, reducing apoptosis and ROS accumulation in damaged renal cells, and ultimately promoting cell migration.

CONCLUSION

The present study underscores the possibility of employing advanced techniques to maximize the therapeutic attributes of exosomes produced from WJ-MSC spheroid for improved recovery outcomes in ischemia-reperfusion injuries.

Downregulation of IL-1β/p38 mitogen activated protein kinase pathway by diacerein protects against kidney ischemia/reperfusion injury in rats

Renal ischemia-reperfusion (I/R) can be precipitated by multiple clinical situations that lead to impaired renal function and associated mortality. The resulting tubular cell damage is the outcome of complex disorders including, an inflammatory process with an overproduction of cytokines. Here, diacerein (DIA), an inhibitor of proinflammatory cytokine interleukin-1 beta (IL-1β), was investigated against renal I/R in rats. DIA was orally administrated (50 mg/kg/day) for ten days before bilateral ischemia for 45 min with subsequent 2 hr. reperfusion. Interestingly, DIA alleviated the renal dysfunction and histopathological damage in the renal tissues. Pretreatment with DIA corrected the oxidative imbalance by prevented reduction in antioxidant levels of GSH and SOD, while it decreased the elevation of the oxidative marker, MDA. In addition, DIA downregulated IL-1β and TNF-α expression in the renal tissues. Consequent to inhibition of the oxidative stress and inflammatory cascades, DIA inhibited the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK). Therefore, downstream targets for p38 MAPK were also inhibited via DIA which prevented further increases of inflammatory cytokines and the apoptotic marker, caspase-3. Collectively, this study revealed the renoprotective role of DIA for renal I/R and highlighted the role of p38 MAPK encountered in its therapeutic application in renal disease.

Neutrophils and NADPH Oxidases Are Major Contributors to Mild but Not Severe Ischemic Acute Kidney Injury in Mice

Upregulation of free radical-generating NADPH oxidases (NOX), xanthine oxidoreductase (XOR), and neutrophil infiltration-induced, NOX2-mediated respiratory burst contribute to renal ischemia-reperfusion injury (IRI), but their roles may depend on the severity of IRI. We investigated the role of NOX, XOR, and neutrophils in developing IRI of various severities. C57BL/6 and Mcl-1ΔMyelo neutrophil-deficient mice were used. Oxidases were silenced by RNA interference (RNAi) or pharmacologically inhibited. Kidney function, morphology, immunohistochemistry and mRNA expression were assessed. After reperfusion, the expression of NOX enzymes and XOR increased until 6 h and from 15 h, respectively, while neutrophil infiltration was prominent from 3 h. NOX4 and XOR silencing or pharmacological XOR inhibition did not protect the kidney from IRI. Attenuation of NOX enzyme-induced oxidative stress by apocynin and neutrophil deficiency improved kidney function and ameliorated morphological damage after mild but not moderate/severe IRI. The IR-induced postischemic renal functional impairment (BUN, Lcn-2), tubular necrosis score, inflammation (TNF-α, F4/80), and decreases in the antioxidant enzyme (GPx3) mRNA expression were attenuated by both apocynin and neutrophil deficiency. Inhibition of NOX enzyme-induced oxidative stress or the lack of infiltration by NOX2-expressing neutrophils can attenuate reperfusion injury after mild but not moderate/severe renal IR.

Development of an adverse outcome pathway network for nephrotoxicity

Adverse outcome pathways (AOPs) were introduced in modern toxicology to provide evidence-based representations of the events and processes involved in the progression of toxicological effects across varying levels of the biological organisation to better facilitate the safety assessment of chemicals. AOPs offer an opportunity to address knowledge gaps and help to identify novel therapeutic targets. They also aid in the selection and development of existing and new in vitro and in silico test methods for hazard identification and risk assessment of chemical compounds. However, many toxicological processes are too intricate to be captured in a single, linear AOP. As a result, AOP networks have been developed to aid in the comprehension and placement of associated events underlying the emergence of related forms of toxicity-where complex exposure scenarios and interactions may influence the ultimate adverse outcome. This study utilised established criteria to develop an AOP network that connects thirteen individual AOPs associated with nephrotoxicity (as sourced from the AOP-Wiki) to identify several key events (KEs) linked to various adverse outcomes, including kidney failure and chronic kidney disease. Analysis of the modelled AOP network and its topological features determined mitochondrial dysfunction, oxidative stress, and tubular necrosis to be the most connected and central KEs. These KEs can provide a logical foundation for guiding the selection and creation of in vitro assays and in silico tools to substitute for animal-based in vivo experiments in the prediction and assessment of chemical-induced nephrotoxicity in human health.

Ginkgo biloba modulates ET-I/NO signalling in Lead Acetate induced rat model of endothelial dysfunction: Involvement of oxido-inflammatory mediators

This study investigated the modulatory effect of Ginkgo biloba extract on lead acetate-induced endothelial dysfunction. Animals were administered GBE (50 mg/kg and 100 mg/kg orally) after exposures to lead acetate (25 mg/kg orally) for 14 days. Aorta was harvested after euthanasia, the tissue was homogenised, and supernatants were decanted after centrifuging. Oxidative, nitrergic, inflammatory, and anti-apoptotic markers were assayed using standard biochemical procedure, ELISA, and immunohistochemistry, respectively. GBE reduced lead-induced oxidative stress by increasing SOD, GSH, and CAT as well as reducing MDA levels in endothelium. Pro-inflammatory cytokines (TNF-α and IL-6) were reduced while increasing Bcl-2 protein expression. GBE lowered endothelin-I and raised nitrite levels. Histological changes caused by lead acetate were normalised by GBE. Our findings suggest that Ginkgo biloba extract restored endothelin-I and nitric oxide functions by increasing Bcl-2 protein expression and reducing oxido-inflammatory stress in endothelium.

Effects and Mechanisms of Fisetin against Ischemia-reperfusion Injuries: A Systematic Review

BACKGROUND

Ischemia-reperfusion injury (IRI) is a well-known ailment that can disturb organ function.

OBJECTIVES

This systematic review study investigated fisetin's effects and possible mechanisms in attenuating myocardial, cerebral, renal, and hepatic IRIs.

METHODS

This systematic review included studies earlier than Sep 2023 by following the PRISMA statement 2020. After determining inclusion and exclusion criteria and related keywords, bibliographic databases, such as Cochrane Library, PubMed, Web of Science, Embase, and Scopus databases, were used to search the relevant studies. Studies were imported in End- Note X8, and the primary information was recorded in Excel.

RESULTS

Fisetin reduced reactive oxygen species (ROS) generation and upregulated antioxidant enzymes, such as superoxide dismutase (SOD), glutathione (GSH), catalase (CAT), and glutathione peroxidase (GPx), in ischemic tissues. Moreover, fisetin can attenuate oxidative stress by activating phosphoinositide-3-kinase-protein kinase B/Akt (PI3K/Akt) and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways. Fisetin has been indicated to prevent the activation of several pro-inflammatory signaling pathways, including NF-κB (Nuclear factor kappa-light-chain-enhancer of activated B cells) and MAPKs (Mitogen-activated protein kinases). It also inhibits the production of pro-inflammatory cytokines and enzymes like tumor necrosis factor-a (TNF-α), inducible-NO synthase (iNOS), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), interleukin-1β (IL-1β), IL-1, and IL-6. Fisetin attenuates IRI by improving mitochondrial function, anti-apoptotic effects, promoting autophagy, and preserving tissues from histological changes induced by IRIs.

CONCLUSION

Fisetin, by antioxidant, anti-inflammatory, mitochondrial protection, promoting autophagy, and anti-apoptotic properties, can reduce cell injury due to myocardial, cerebral renal, and hepatic IRIs without any significant side effects.

Design and synthesis of 3,4-seco-lupane triterpene derivatives to resist myocardial ischemia-reperfusion injury by inhibiting oxidative stress-mediated mitochondrial dysfunction via the PI3K/AKT/HIF-1α axis

In this study, 86 new seco-lupane triterpenoid derivatives were designed, synthesized, and characterized, and their protective activities against ischemia-reperfusion injury were investigated in vitro and in vivo. Structure-activity relationship studies revealed that most target compounds could protect cardiomyocytes against hypoxia/reoxygenation-induced injury in vitro, with compound 85 being the most active and exhibiting more potent protective activity than clinical first-line drugs. Furthermore, all thiophene derivatives exhibited stronger protective activity than furan, pyridine, and pyrazine derivatives, and the protective activity gradually increased with the extension of the alkyl chain and changed in the substituent. The data from the in-vitro and in-vivo experiments revealed that compound 85 protected mitochondria from damage by inhibiting excessive production of oxidative stressors, such as intracellular ROS, which in turn inhibited the apoptosis and necrotize of cardiomyocytes and reduced infarct size, thereby protecting normal cardiac function. It was associated with enhanced activation of the PI3K/AKT-mediated HIF-1α signaling pathway. Therefore, compound 85 acts as an oxidative stress inhibitor, blocks ROS production, protects mitochondria and cells from myocardial ischemia/reperfusion (MI/R) injury, and represents an effective new drug for treating MI/R injury.

Resveratrol alleviates high glucose-induced oxidative stress and apoptosis in rat cardiac microvascular endothelial cell through AMPK/Sirt1 activation

Diabetic cardiomyopathy (DCM) is a common complication of diabetes. DCM causes extensive lesions on cardiac microvasculature that is predominantly cardiac microvascular endothelial cells (CMECs). Reducing high glucose (HG)-induced damage such as oxidative damage and apoptosis could alleviate the development of DCM. The natural polyphenol resveratrol (RSV) is widely suggested as a cardioprotective agent that protect against DCM. However, limited evidence supports the protection of RSV against oxidative damage and apoptosis and study on the direct effects of RSV in CMEC is missing. Therefore, the current paper aimed to illustrate if RSV could attenuate oxidative stress and apoptosis in CMEC and to investigate the underlying mechanisms. Our data showed that HG elevated reactive oxygen species, malondialdehyde, decreased superoxide dismutase activity, increased apoptotic cell percentage in CMEC, which were reversed by RSV administration. In addition, RSV demonstrated antioxidative and anti-apoptotic effects in CMEC through AMPK/Sirt1 activation, further confirmed by AMPK inhibition or Sirt1 silencing. This study provides new evidence to support RSV as a potential cardioprotective alternative in treating DCM.

Ginkgo Biloba and Long COVID: In Vivo and In Vitro Models for the Evaluation of Nanotherapeutic Efficacy

Coronavirus infections are neuroinvasive and can provoke injury to the central nervous system (CNS) and long-term illness consequences. They may be associated with inflammatory processes due to cellular oxidative stress and an imbalanced antioxidant system. The ability of phytochemicals with antioxidant and anti-inflammatory activities, such as Ginkgo biloba, to alleviate neurological complications and brain tissue damage has attracted strong ongoing interest in the neurotherapeutic management of long COVID. Ginkgo biloba leaf extract (EGb) contains several bioactive ingredients, e.g., bilobalide, quercetin, ginkgolides A-C, kaempferol, isorhamnetin, and luteolin. They have various pharmacological and medicinal effects, including memory and cognitive improvement. Ginkgo biloba, through its anti-apoptotic, antioxidant, and anti-inflammatory activities, impacts cognitive function and other illness conditions like those in long COVID. While preclinical research on the antioxidant therapies for neuroprotection has shown promising results, clinical translation remains slow due to several challenges (e.g., low drug bioavailability, limited half-life, instability, restricted delivery to target tissues, and poor antioxidant capacity). This review emphasizes the advantages of nanotherapies using nanoparticle drug delivery approaches to overcome these challenges. Various experimental techniques shed light on the molecular mechanisms underlying the oxidative stress response in the nervous system and help comprehend the pathophysiology of the neurological sequelae of SARS-CoV-2 infection. To develop novel therapeutic agents and drug delivery systems, several methods for mimicking oxidative stress conditions have been used (e.g., lipid peroxidation products, mitochondrial respiratory chain inhibitors, and models of ischemic brain damage). We hypothesize the beneficial effects of EGb in the neurotherapeutic management of long-term COVID-19 symptoms, evaluated using either in vitro cellular or in vivo animal models of oxidative stress.

Novel, Innovative Models to Study Ischemia/Reperfusion-Related Redox Damage in Organ Transplantation

The implementation of ex vivo organ machine perfusion (MP) into clinical routine undoubtedly helped to increase the donor pool. It enables not just organ assessment, but potentially regeneration and treatment of marginal organs in the future. During organ procurement, redox-stress triggered ischemia-reperfusion injury (IRI) is inevitable, which in addition to pre-existing damage negatively affects such organs. Ex vivo MP enables to study IRI-associated tissue damage and its underlying mechanisms in a near to physiological setting. However, research using whole organs is limited and associated with high costs. Here, in vitro models well suited for early stage research or for studying particular disease mechanisms come into play. While cell lines convince with simplicity, they do not exert all organ-specific functions. Tissue slice cultures retain the three-dimensional anatomical architecture and cells remain within their naïve tissue-matrix configuration. Organoids may provide an even closer modelling of physiologic organ function and spatial orientation. In this review, we discuss the role of oxidative stress during ex vivo MP and the suitability of currently available in vitro models to further study the underlying mechanisms and to pretest potential treatment strategies.

Experimental Modeling of Damaging and Protective Hypoxia of the Mammalian Brain

Currently, there is a new surge of interest in the problem of hypoxia, almost lost in recent decades. Due to the fact that the circle of competent specialists in this field has significantly narrowed, it is necessary to carry out an intensive exchange of knowledge. In order to inform a wide range of interested researchers and doctors, this review summarizes the current understanding of hypoxia, its pathogenic and adaptogenic consequences, as well as key physiological and molecular mechanisms that implement the response to hypoxia at various levels-from cellular to organismic. The review presents a modern classification of forms of hypoxia, the understanding of which is necessary for the formation of a scientifically based approach to experimental modeling of hypoxic states. An analysis of the literature covering the history and current level of hypoxia modeling in mammals and human experiments, including methods for creating moderate hypoxia used to increase the resistance of the nervous system to severe forms of hypoxia and other extreme factors, is carried out. Special attention is paid to the discussion of the features and limitations of various approaches to the creation of hypoxia, as well as the disclosure of the potential for the practical application of moderate hypoxic effects in medicine.

How to improve results after DCD (donation after circulation death)

The shortage of organs for transplantation has led health professionals to look for alternative sources of donors. One of the avenues concerns donors who have died after circulatory arrest. This is a special situation because the organs from these donors are exposed to warm ischaemia-reperfusion lesions that are unavoidable during the journey of the organs from the donor to the moment of transplantation in the recipient. We will address and discuss the key issues from the perspective of team organization, legislation and its evolution, and the ethical framework. In a second part, the avenues to improve the quality of organs will be presented following the itinerary of the organs between the donor and the recipient. The important moments from the point of view of therapeutic strategy will be put into perspective. New connections between key players involved in pathophysiological mechanisms and implications for innate immunity and injury processes are among the avenues to explore. Technological developments to improve the quality of organs from these recipients will be analyzed, such as perfusion techniques with new modalities of temperatures and oxygenation. New molecules are being investigated for their potential role in protecting these organs and an analysis of potential prospects will be proposed. Finally, the important perspectives that seem to be favored will be discussed in order to reposition the use of deceased donors after circulatory arrest. The use of these organs has become a routine procedure and improving their quality and providing the means for their evaluation is absolutely inevitable.

Research hotspots and development trends of microRNA in ischemia-reperfusion: network analysis of academic journals oriented by bibliometric and visualization

Background

Ischemia-reperfusion (IR) injury can occur in the heart, brain, liver, lung, kidney, and other important organs, and may greatly increase disease mortality. MicroRNAs (miRNAs) have a variety of functions, including regulating cell differentiation, proliferation, and apoptosis. In the past 10 years, many studies on miRNAs in IR have been conducted. This study involved a visual analysis of these studies, and a discussion of research hotspots, trends, and frontiers of this topic.

Methods

A total of 1,518 articles published between 2012 and 2022 on the topic of miRNA and IR and listed in the Web of Science database were analyzed visually using CiteSpace. Cooperative networks, literature citations, and keyword co-occurrence were analyzed.

Results

Of the 1,518 articles, most were published after 2018, and a rapid growth in numbers of publications was seen after 2019. Articles from China numbered the highest, followed by the United States and Canada. It has been found that many miRNAs are involved in the occurrence of IR, with various regulatory mechanisms and signaling pathways. The literature clustering generated by literature co-citation analysis and the keyword co-occurrence network showed that the previous miRNA research on IR had mainly focused on the following topics: myocardial infarction, ischemic stroke, acute kidney injury, oxidative stress, and inflammatory response. More attention has been paid to long noncoding RNA (lncRNA) and exosomes, with much exploration having been conducted in these areas.

Conclusions

Although miRNA is involved in the occurrence and development of IR, as a clinical intervention target for IR, further research is still needed.

Importance of oxidative stress in the evaluation of acute pulmonary embolism severity

Background

Pulmonary embolism (PE) is a common and potentially life-threatening disorder. Our study was aimed to investigate whether oxidative stress markers can be used as clinical markers in the evaluation of acute PE (APE) severity.

Methods

47 patients with objectively documented diagnosis of APE were recorded. Of these patients, 14 had low-risk PE, 16 had moderate-risk PE, and 17 had high-risk PE. 21 healthy subjects were also enrolled in this study. Ischemia-modified albumin (IMA), prooxidants-antioxidants balance (PAB), advanced protein oxidation products (AOPPs), and ferric reducing antioxidant power (FRAP) were measured as oxidative stress parameters to evaluate the role of oxidative stress.

Results

In the low-risk and moderate-risk APE groups, AOPPs and PAB levels were significantly higher and FRAP levels were significantly lower than those in the control group. AOPPs and IMA levels in the patients with high-risk PE were significantly higher than those in both the low-risk and moderate-risk APE patients. There was a significant correlation between levels of AOPPs and the levels of both IMA (r: 0.462, p < 0.001) and PAB (r:0.378, p < 0.005). Serum FRAP levels were negatively correlated with PAB (r:− 0.683, p < 0.001) and AOPPs levels (r:− 0,384, p < 0.001). There was also a significant positive correlation between the serum IMA and PAB levels.

Conclusions

We clearly demonstrated that reactive oxygen species formation is significantly enhanced in APE. IMA and AOPPs may be used as clinical markers in the evaluation of APE severity in clinical practice. However, further studies with larger patient populations and longer follow-up periods are required to confirm the mechanisms underlying these findings.

Protective effect of fluoxetine against oxidative stress induced by renal ischemia-reperfusion injury via the regulation of miR-450b-5p/Nrf2 axis

The present study was performed to assess the protective effect of fluoxetine (FLX) on renal ischemia-reperfusion injury (IRI) via the regulation of miR-450b-5p/Nrf2 axis in male rats. In vivo, these male rats were randomly divided into different treatment groups. The rats were administered with FLX (20 mg/kg, intraperitoneally) once daily for 3 days before operation. The pathomorphological changes of renal tissues were assessed by histological examination and Masson staining. In vitro, HK-2 cells were used to detect the activity by CCK-8 assay in Hypoxia/Reoxygenation (H/R) group and Hypoxia/Reoxygenation+Fluoxetine (H/R+FLX) group. In addition, the oxidative stress biomarkers were evaluated. Subsequently, Nrf2, NF-κB, and Nrf2-dependent antioxidant enzymes, were detected by Western blot assay. In vivo, the pathological changes and serological renal function were significantly relieved in the rats with the pre-treatment of FLX, compared to IRI group. After FLX stimulation, the expression levels of oxidative stress indices significantly decreased, while tissue antioxidant indices significantly increased, compared to IRI group. The differently expressed miRNAs on renal IRI in male rats were screened out by miRNA microarray, especially showing that miR-450b-5p was selected as the target miRNA. Following miR-450b-5p agomir injection, the pathological changes and oxidative stress biomarkers significantly aggravated, whether in IRI group or IRI+FLX group. Bioinformatics analysis and double-luciferase reporter assay demonstrated that miR-450b-5p directly targeted Nrf2. The expression level of NF-κB significantly increased, while the expression levels of Nrf2 and Nrf2-dependent antioxidant enzymes significantly decreased after miR-450b-5p agomir injection. Furthermore, the expression levels of Nrf2 and it-dependent antioxidant enzymes were apparently increased in ischemic kidney after the transfection of miR-450b-5p mimic+recombination protein Nrf2, as well as the decreased expression levels of intracellular ROS and iNOS. In vitro, FLX significantly increased HK-2 cell viability, and relieved H/R HK-2 cell oxidative injury via down-regulating ROS and iNOS. In addition, H/R-induced oxidative damage was recovered with miR-450b-5p mimic and recombination protein Nrf2. Consequently, FLX played an important protective role in renal IRI-induced oxidative damage by promoting antioxidation via targeting miR-450b-5p/Nrf2 axis.

A Potential Route to Reduce Ischemia/Reperfusion Injury in Organ Preservation

The pathophysiological process of ischemia and reperfusion injury (IRI), an inevitable step in organ transplantation, causes important biochemical and structural changes that can result in serious organ damage. IRI is relevant for early graft dysfunction and graft survival. Today, in a global context of organ shortages, most organs come from extended criteria donors (ECDs), which are more sensitive to IRI. The main objective of organ preservation solutions is to protect against IRI through the application of specific, nonphysiological components, under conditions of no blood or oxygen, and then under conditions of metabolic reduction by hypothermia. The composition of hypothermic solutions includes osmotic and oncotic buffering components, and they are intracellular (rich in potassium) or extracellular (rich in sodium). However, above all, they all contain the same type of components intended to protect against IRI, such as glutathione, adenosine and allopurinol. These components have not changed for more than 30 years, even though our knowledge of IRI, and much of the relevant literature, questions their stability or efficacy. In addition, several pharmacological molecules have been the subjects of preclinical studies to optimize this protection. Among them, trimetazidine, tacrolimus and carvedilol have shown the most benefits. In fact, these drugs are already in clinical use, and it is a question of repositioning them for this novel use, without additional risk. This new strategy of including them would allow us to shift from cold storage solutions to cold preservation solutions including multitarget pharmacological components, offering protection against IRI and thus protecting today's more vulnerable organs.

ALOX15-launched PUFA-phospholipids peroxidation increases the susceptibility of ferroptosis in ischemia-induced myocardial damage

Myocardial ischemia/reperfusion (I/R) injury is a classic type of cardiovascular disease characterized by injury to cardiomyocytes leading to various forms of cell death. It is believed that irreversible myocardial damage resulted from I/R occurs due to oxidative stress evoked during the reperfusion phase. Here we demonstrate that ischemia triggers a specific redox reaction of polyunsaturated fatty acids (PUFA)-phospholipids in myocardial cells, which acts as a priming signaling that initiates the outbreak of robust oxidative damage in the reperfusion phase. Using animal and in vitro models, the crucial lipid species in I/R injury were identified to be oxidized PUFAs enriched phosphatidylethanolamines. Using multi-omics, arachidonic acid 15-lipoxygenase-1 (ALOX15) was identified as the primary mediator of ischemia-provoked phospholipid peroxidation, which was further confirmed using chemogenetic approaches. Collectively, our results reveal that ALOX15 induction in the ischemia phase acts as a “burning point” to ignite phospholipid oxidization into ferroptotic signals. This finding characterizes a novel molecular mechanism for myocardial ischemia injury and offers a potential therapeutic target for early intervention of I/R injury.

Chemistry of Hydrogen Peroxide Formation and Elimination in Mammalian Cells, and Its Role in Various Pathologies

Hydrogen peroxide (H2O2) is a compound involved in some mammalian reactions and processes. It modulates and signals the redox metabolism of cells by acting as a messenger together with hydrogen sulfide (H2S) and the nitric oxide radical (•NO), activating specific oxidations that determine the metabolic response. The reaction triggered determines cell survival or apoptosis, depending on which downstream metabolic pathways are activated. There are several ways to produce H2O2 in cells, and cellular systems tightly control its concentration. At the cellular level, the accumulation of hydrogen peroxide can trigger inflammation and even apoptosis, and when its concentration in the blood reaches toxic levels, it can lead to bioenergetic failure. This review summarizes existing research from a chemical perspective on the role of H2O2 in various enzymatic pathways and how this biochemistry leads to physiological or pathological responses.

Preservation of Organs to Be Transplanted: An Essential Step in the Transplant Process

Organ transplantation remains the treatment of last resort in case of failure of a vital organ (lung, liver, heart, intestine) or non-vital organ (essentially the kidney and pancreas) for which supplementary treatments exist. It remains the best alternative both in terms of quality-of-life and life expectancy for patients and of public health expenditure. Unfortunately, organ shortage remains a widespread issue, as on average only about 25% of patients waiting for an organ are transplanted each year. This situation has led to the consideration of recent donor populations (deceased by brain death with extended criteria or deceased after circulatory arrest). These organs are sensitive to the conditions of conservation during the ischemia phase, which have an impact on the graft’s short- and long-term fate. This evolution necessitates a more adapted management of organ donation and the optimization of preservation conditions. In this general review, the different aspects of preservation will be considered. Initially done by hypothermia with the help of specific solutions, preservation is evolving with oxygenated perfusion, in hypothermia or normothermia, aiming at maintaining tissue metabolism. Preservation time is also becoming a unique evaluation window to predict organ quality, allowing repair and/or optimization of recipient choice.

Oxidative Injury in Ischemic Stroke: A Focus on NADPH Oxidase 4

Ischemic stroke is a leading cause of disability and mortality worldwide. Thus, it is urgent to explore its pathophysiological mechanisms and find new therapeutic strategies for its successful treatment. The relationship between oxidative stress and ischemic stroke is increasingly appreciated and attracting considerable attention. ROS serves as a source of oxidative stress. It is a byproduct of mitochondrial metabolism but primarily a functional product of NADPH oxidases (NOX) family members. Nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) is most closely related to the formation of ROS during ischemic stroke. Its expression is significantly upregulated after cerebral ischemia, making it a promising target for treating ischemic stroke. Several drugs targeting NOX4, such as SCM-198, Iso, G-Rb1, betulinic acid, and electroacupuncture, have shown efficacy as treatments of ischemic stroke. MTfp-NOX4 POC provides a novel insight for the treatment of stroke. Combinations of these therapies also provide new approaches for the therapy of ischemic stroke. In this review, we summarize the subcellular location, expression, and pathophysiological mechanisms of NOX4 in the occurrence and development of ischemic stroke. We also discuss the therapeutic strategies and related regulatory mechanisms for treating ischemic stroke. We further comment on the shortcomings of current NOX4-targeted therapy studies and the direction for improvement.

Biomarkers and Utility of the Antioxidant Potential of Probiotic Lactobacilli and Bifidobacteria as Representatives of the Human Gut Microbiota

Lactobacilli and bifidobacteria are an important part of human gut microbiota. Among numerous benefits, their antioxidant properties are attracting more and more attention. Multiple in vivo and in vitro studies have demonstrated that lactobacilli and bifidobacteria, along with their cellular components, possess excellent antioxidant capacity, which provides a certain degree of protection to the human body against diseases associated with oxidative stress. Recently, lactobacilli and bifidobacteria have begun to be considered as a new source of natural antioxidants. This review summarizes the current state of research on various antioxidant properties of lactobacilli and bifidobacteria. Special emphasis is given to the mechanisms of antioxidant activity of these bacteria in the human gut microbiota, which involve bacterial cell components and metabolites. This review is also dedicated to the genes involved in the antioxidant properties of lactobacilli and bifidobacteria strains as indicators of their antioxidant potential in human gut microbiota. Identification of the antioxidant biomarkers of the gut microbiota is of great importance both for creating diagnostic systems for assessing oxidative stress and for choosing strategies aimed at restoring the normal functioning of the microbiota and, through it, restoring human health. In this review, the practical application of probiotic strains with proven antioxidant properties to prevent oxidative stress is also considered.