Hypoxic ischemic encephalopathy (HIE).

Introduction: The morbidity and mortality of acute ischemic hypoxic encephalopathy in newborns have not been dramatically modified over the last 20 years. The purpose of this review is to describe the use of hyperbaric oxygenation therapy (HBOT) in the management of acute ischemic hypoxic encephalopathy in newborns. Methods: A review of the medical literature was conducted on the use of HBOT in the pathophysiology of this condition and its impact on outcomes of patients treated at an early stage. Results: When HBOT is administered promptly, it can promote the survival of the penumbra, modulate the cytokine storm, modify inflammatory cascades, restore mitochondrial function, inhibit apoptosis, reinstate cellular communication and cytoskeleton function, reinstall the functioning of the kinase system, reduce cytotoxic and tissue edema, promote microcirculation, and provide an antioxidant effect. All these secondary mechanisms aid in saving, rescuing, and protecting the marginal tissue. Conclusion: When used promptly, HBOT is a non-invasive adjunct treatment that can preserve the marginal tissue affected by ischemia, hypoxia, meet the metabolic needs of the penumbra, reduce inflammatory cascades, prevent the extension of the damaged tissue, and modulate ischemia-reperfusion injury.

Distinct effects of intravenous bone marrow-derived mesenchymal stem cell therapy on ischemic and non-ischemic lungs after ischemia-reperfusion injury.

BACKGROUND: The preclinical efficacy of mesenchymal stem cell (MSC) therapy after intravenous infusion has been promising, but clinical studies have yielded only modest results. Although most preclinical studies have focused solely on the ischemic lung, it is crucial to evaluate both lungs after ischemia-reperfusion injury, considering the various mechanisms involved. This study aimed to bridge this gap by assessing the acute effects of bone marrow MSC(BM) infusion before ischemic insult and evaluating both ischemic and non-ischemic lungs after reperfusion. METHODS: Eighteen male Wistar rats (403 ± 23 g) were anesthetized and mechanically ventilated using a protective strategy. After baseline data collection, the animals were randomized to 3 groups (n = 6/group): (1) SHAM; (2) ischemia-reperfusion (IR), and (3) intravenous MSC(BM) infusion followed by IR. Ischemia was induced by complete clamping of the left hilum, followed by 1 h of reperfusion after clamp removal. At the end of the experiment, the right and left lungs (non-ischemic and ischemic, respectively) were collected for immunohistochemistry and molecular biology analysis. RESULTS: MSC(BM)s reduced endothelial cell damage and apoptosis markers and improved markers associated with endothelial cell integrity in both lungs. In addition, gene expression of catalase and nuclear factor erythroid 2-related factor 2 increased after MSC(BM) therapy. In the ischemic lung, MSC(BM) therapy mitigated endothelial cell damage and apoptosis and increased gene expression associated with endothelial cell integrity. Conversely, in the non-ischemic lung, apoptosis gene expression increased in the IR group but not after MSC(BM) therapy. CONCLUSION: This study demonstrates distinct effects of MSC(BM) therapy on ischemic and non-ischemic lungs after ischemia-reperfusion injury. The findings underscore the importance of evaluating both lung types in ischemia-reperfusion studies, offering insights into the therapeutic potential of MSC(BM) therapy in the context of lung injury.

Renal protection after hemorrhagic shock in rats: Possible involvement of SUMOylation.

Hemorrhagic shock (HS), a leading cause of preventable death, is characterized by severe blood loss and inadequate tissue perfusion. Reoxygenation of ischemic tissues exacerbates organ damage through ischemia-reperfusion injury. SUMOylation has been shown to protect neurons after stroke and is upregulated in response to cellular stress. However, the role of SUMOylation in organ protection after HS is unknown. This study aimed to investigate SUMOylation-mediated organ protection following HS. Male Wistar rats were subjected to HS (blood pressure of 40 ± 2 mmHg, for 90 min) followed by reperfusion. Blood, kidney, and liver samples were collected at various time points after reperfusion to assess organ damage and investigate the profile of SUMO1 and SUMO2/3 conjugation. In addition, human kidney cells (HK-2), treated with the SUMOylation inhibitor TAK-981 or overexpressing SUMO proteins, were subjected to oxygen and glucose deprivation to investigate the role of SUMOylation in hypoxia/reoxygenation injury. The animals presented progressive multiorgan dysfunction, except for the renal system, which showed improvement over time. Compared to the liver, the kidneys displayed distinct patterns in terms of oxidative stress, apoptosis activation, and tissue damage. The global level of SUMO2/3 in renal tissue was also distinct, suggesting a differential role. Pharmacological inhibition of SUMOylation reduced cell viability after hypoxia-reoxygenation damage, while overexpression of SUMO1 or SUMO2 protected the cells. These findings suggest that SUMOylation might play a critical role in cellular protection during ischemia-reperfusion injury in the kidneys, a role not observed in the liver. This difference potentially explains the renal resilience observed in HS animals when compared to other systems.

Tapping into Nature's Arsenal: Harnessing the Potential of Natural Antioxidants for Human Health and Disease Prevention.

Numerous natural antioxidants commonly found in our daily diet have demonstrated significant benefits for human health and various diseases by counteracting the impact of reactive oxygen and nitrogen species. Their chemical properties enable a range of biological actions, including antihypertensive, antimicrobial, anti-inflammatory, anti-fibrotic, and anticancer effects. Despite promising outcomes from preclinical studies, ongoing debate persists regarding their reproducibility in human clinical models. This controversy largely stems from a lack of understanding of the pharmacokinetic properties of these compounds, coupled with the predominant focus on monotherapies in research, neglecting potential synergistic effects arising from combining different antioxidants. This study aims to provide an updated overview of natural antioxidants, operating under the hypothesis that a multitherapeutic approach surpasses monotherapy in efficacy. Additionally, this study underscores the importance of integrating these antioxidants into the daily diet, as they have the potential to prevent the onset and progression of various diseases. To reinforce this perspective, clinical findings pertaining to the treatment and prevention of non-alcoholic fatty liver disease and conditions associated with ischemia and reperfusion phenomena, including myocardial infarction, postoperative atrial fibrillation, and stroke, are presented as key references.

Protective effects of Ruscus extract in combination with ascorbic acid and hesperidine methylchalcone on increased leukocyte-endothelial interaction and macromolecular permeability induced by ischemia reperfusion injury.

BACKGROUND: Despite the well-recognized effectiveness of Ruscus aculetus extract combined or not with ascorbic acid (AA) and hesperidine methyl chalcone (HMC) on ischemia reperfusion (I/R) injury protection, little is known about the contribution of each constituent for this effect. OBJECTIVE: To investigate the effects of AA and HMC combined or not with Ruscus extract on increased macromolecular permeability and leukocyte-endothelium interaction induced by I/R injury. METHODS: Hamsters were treated daily during two weeks with filtered water (placebo), AA (33, 100 and 300 mg/kg/day) and HMC (50, 150 and 450 mg/kg/day) combined or not with Ruscus extract (50, 150 and 450 mg/kg/day). On the day of experiment, the cheek pouch microcirculation underwent 30 min of ischemia, and the number of rolling and adherent leukocytes and leaky sites were evaluated before ischemia and during 45 min of reperfusion. RESULTS: Ruscus extract combined with AA and HMC (Ruscus extract mixture) significantly prevented post-ischemic increase in leukocyte rolling and adhesion and macromolecular permeability compared to placebo and these effects were more prominent than AA and HMC alone on leukocyte adhesion and macromolecular leakage. CONCLUSION: Ruscus extract mixture were more effective than its isolated constituents in protect the hamster cheek pouch microcirculation against I/R injury.

Air pollution aggravates renal ischaemia-reperfusion-induced acute kidney injury.

Chronic kidney disease (CKD) has emerged as a significant global public health concern. Recent epidemiological studies have highlighted the link between exposure to fine particulate matter (PM2.5) and a decline in renal function. PM2.5 exerts harmful effects on various organs through oxidative stress and inflammation. Acute kidney injury (AKI) resulting from ischaemia-reperfusion injury (IRI) involves biological processes similar to those involved in PM2.5 toxicity and is a known risk factor for CKD. The objective of this study was to investigate the impact of PM2.5 exposure on IRI-induced AKI. Through a unique environmentally controlled setup, mice were exposed to urban PM2.5 or filtered air for 12 weeks before IRI followed by euthanasia 48 h after surgery. Animals exposed to PM2.5 and IRI exhibited reduced glomerular filtration, impaired urine concentration ability, and significant tubular damage. Further, PM2.5 aggravated local innate immune responses and mitochondrial dysfunction, as well as enhancing cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway activation. This increased renal senescence and suppressed the anti-ageing protein klotho, leading to early fibrotic changes. In vitro studies using proximal tubular epithelial cells exposed to PM2.5 and hypoxia/reoxygenation revealed heightened activation of the STING pathway triggered by cytoplasmic mitochondrial DNA, resulting in increased tubular damage and a pro-inflammatory phenotype. In summary, our findings imply a role for PM2.5 in sensitising proximal tubular epithelial cells to IRI-induced damage, suggesting a plausible association between PM2.5 exposure and heightened susceptibility to CKD in individuals experiencing AKI. Strategies aimed at reducing PM2.5 concentrations and implementing preventive measures may improve outcomes for AKI patients and mitigate the progression from AKI to CKD. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Oncologic Outcomes of Interventions to Decrease Allograft Ischemia-Reperfusion Injury within Patients Undergoing Liver Transplantation for Hepatocellular Carcinoma: A Systematic Review.

Ischemia-reperfusion injury (IRI) during liver transplantation has been implicated in the recurrence of hepatocellular carcinoma (HCC). This systematic review aimed to evaluate interventions to reduce IRI during liver transplantation for HCC and their impact on oncologic outcomes. A comprehensive literature search retrieved four retrospective studies involving 938 HCC patients, utilising interventions such as post-operative prostaglandin administration, hypothermic machine perfusion, and normothermic machine perfusion. Overall, treated patients exhibited reduced post-operative hepatocellular injury and inflammation and significantly enhanced recurrence-free survival. Despite these promising results, the impact of these interventions on overall survival remains unclear. This underscores the imperative for further prospective research to comprehensively understand the efficacy of these interventions in HCC patients undergoing transplantation. The findings highlight the potential benefits of these strategies while emphasising the need for continued investigation into their overall impact.

Identification of potential crucial cuproptosis-related genes in myocardial ischemia-reperfusion injury through the bioinformatic analysis.

BACKGROUND: Cuproptosis is known to regulate diverse physiological functions in many diseases, but its role in regulating Myocardial Ischemia-Reperfusion Injury (MI/RI) remains unclear. METHODS: For this purpose, the MI/RI microarray datasets GSE61592 were downloaded from the Gene Expression Omnibus (GEO) database, and the Differently Expressed Genes (DEGs) in MI/RI were identified using R software. Moreover, the MI/RI mice model was established to confirm further the diagnostic value of Pyruvate Dehydrogenase B (Pdhb), Dihydrolipoamide S-acetyltransferase (Dlat), and Pyruvate dehydrogenase E1 subunit alpha 1 (Pdhα1). RESULTS: The analysis of microarray datasets GSE61592 revealed that 798 genes were upregulated and 768 were downregulated in the myocardial tissue of the ischemia-reperfusion injury mice. Furthermore, Dlat, Pdhb, Pdhα1, and cuproptosis-related genes belonged to the downregulated genes. The receiver operating characteristics curve analysis results indicated that the Dlat, Pdhb, and Pdhα1 levels were downregulated in MI/RI and were found to be potential biomarkers for MI/RI diagnosis and prognosis. Similarly, analysis of Dlat, Pdhb, and Pdhα1 levels in the MI/RI mice revealed Pdhb being the key diagnostic marker. CONCLUSIONS: This study demonstrated the prognostic value of cuproptosis-related genes (Dlat, Pdhb, and Pdhα1), especially Pdhb, MI/RI, providing new insight into the MI/RI treatment.

Genome-wide DNA methylation and transcriptomic analysis of liver tissues subjected to early ischemia/reperfusion injury upon human liver transplantation.

INTRODUCTION AND OBJECTIVES: Epigenetic changes represent a mechanism connecting external stresses with long-term modifications of gene expression programs. In solid organ transplantation, ischemia-reperfusion injury (IRI) appears to induce epigenomic changes in the graft, although the currently available data are extremely limited. The present study aimed to characterize variations in DNA methylation and their effects on the transcriptome in liver transplantation from brain-dead donors. PATIENTS AND METHODS: 12 liver grafts were evaluated through serial biopsies at different timings in the procurement-transplantation process: T0 (warm procurement, in donor), T1 (bench surgery), and T2 (after reperfusion, in recipient). DNA methylation (DNAm) and transcriptome profiles of biopsies were analyzed using microarrays and RNAseq. RESULTS: Significant variations in DNAm were identified, particularly between T2 and T0. Functional enrichment of the best 1000 ranked differentially methylated promoters demonstrated that 387 hypermethylated and 613 hypomethylated promoters were involved in spliceosomal assembly and response to biotic stimuli, and inflammatory immune responses, respectively. At the transcriptome level, T2 vs. T0 showed an upregulation of 337 and downregulation of 61 genes, collectively involved in TNF-α, NFKB, and interleukin signaling. Cell enrichment analysis individuates macrophages, monocytes, and neutrophils as the most significant tissue-cell type in the response. CONCLUSIONS: In the process of liver graft procurement-transplantation, IRI induces significant epigenetic changes that primarily act on the signaling pathways of inflammatory responses dependent on TNF-α, NFKB, and interleukins. Our DNAm datasets are the early IRI methylome literature and will serve as a launch point for studying the impact of epigenetic modification in IRI.

Puerarin protects the fatty liver from ischemia-reperfusion injury by regulating the PI3K/AKT signaling pathway

Abstract The incidence of non-alcoholic fatty liver (NAFLD) remains high, and many NAFLD patients suffer from severe ischemia-reperfusion injury (IRI). Currently, no practical approach can be used to treat IRI. Puerarin plays a vital role in treating multiple diseases, such as NAFLD, stroke, diabetes, and high blood pressure. However, its role in the IRI of the fatty liver is still unclear. We aimed to explore whether puerarin could protect the fatty liver from IRI. C57BL/6J mice were fed with a high‐fat diet (HFD) followed by ischemia reperfusion injury. We showed that hepatic IRI was more severe in the fatty liver compared with the normal liver, and puerarin could significantly protect the fatty liver against IRI and alleviate oxidative stress. The PI3K-AKT signaling pathway was activated during IRI, while liver steatosis decreased the level of activation. Puerarin significantly protected the fatty liver from IRI by reactivating the PI3K-AKT signaling pathway. However, LY294002, a PI3K-AKT inhibitor, attenuated the protective effect of puerarin. In conclusion, puerarin could significantly protect the fatty liver against IRI by activating the PI3K-AKT signaling pathway.

Middle-age abolishes cardioprotection conferred by thioredoxin-1 in mice.

Thioredoxin-1 (Trx1) has cardioprotective effects on ischemia/reperfusion (I/R) injury, although its role in ischemic postconditioning (PostC) in middle-aged mice is not understood. This study aimed to evaluate if combining two cardioprotective strategies, such as Trx1 overexpression and PostC, could exert a synergistic effect in reducing infarct size in middle-aged mice. Young or middle-aged wild-type mice (Wt), transgenic mice overexpressing Trx1, and dominant negative (DN-Trx1) mutant of Trx1 mice were used. Mice hearts were subjected to I/R or PostC protocol. Infarct size, hydrogen peroxide (H2O2) production, protein nitration, Trx1 activity, mitochondrial function, and Trx1, pAkt and pGSK3ß expression were measured. PostC could not reduce infarct size even in the presence of Trx1 overexpression in middle-aged mice. This finding was accompanied by a lack of Akt and GSK3ß phosphorylation, and Trx1 expression (in Wt group). Trx1 activity was diminished and H2O2 production and protein nitration were increased in middle-age. The respiratory control rate dropped after I/R in Wt-Young and PostC restored this value, but not in middle-aged groups. Our results showed that Trx1 plays a key role in the PostC protection mechanism in young but not middle-aged mice, even in the presence of Trx1 overexpression.

High-Density Lipoproteins at the Interface between the NLRP3 Inflammasome and Myocardial Infarction.

Despite significant therapeutic advancements, morbidity and mortality following myocardial infarction (MI) remain unacceptably high. This clinical challenge is primarily attributed to two significant factors: delayed reperfusion and the myocardial injury resulting from coronary reperfusion. Following reperfusion, there is a rapid intracellular pH shift, disruption of ionic balance, heightened oxidative stress, increased activity of proteolytic enzymes, initiation of inflammatory responses, and activation of several cell death pathways, encompassing apoptosis, necroptosis, and pyroptosis. The inflammatory cell death or pyroptosis encompasses the activation of the intracellular multiprotein complex known as the NLRP3 inflammasome. High-density lipoproteins (HDL) are endogenous particles whose components can either promote or mitigate the activation of the NLRP3 inflammasome. In this comprehensive review, we explore the role of inflammasome activation in the context of MI and provide a detailed analysis of how HDL can modulate this process.

Breviscapine alleviates myocardial ischemia-reperfusion injury in diabetes rats

Purpose: To investigate the protective effect of breviscapine on myocardial ischemia-reperfusion injury (MIRI) in diabetes rats. Methods: Forty rats were divided into control, diabetes, MIRI of diabetes, and treatment groups. The MIRI of diabetes model was established in the latter two groups. Then, the treatment group was treated with 100 mg/kg breviscapine by intraperitoneal injection for 14 consecutive days. Results: After treatment, compared with MIRI of diabetes group, in treatment group the serum fasting blood glucose, fasting insulin, homeostasis model assessment of insulin resistance, and glycosylated hemoglobin levels decreased, the serum total cholesterol, triacylglycerol, and low-density lipoprotein cholesterol levels decreased, the serum high-density lipoprotein cholesterol level increased, the heart rate decreased, the mean arterial pressure, left ventricular ejection fraction, and fractional shortening increased, the serum cardiac troponin I, and creatine kinase-MB levels decreased, the myocardial tumor necrosis factor α and interleukin-6 levels decreased, the myocardial superoxide dismutase level increased, and the myocardial malondialdehyde level decreased (all P < 0.05). Conclusions: For treating MIRI of diabetes in rats, the breviscapine can reduce the blood glucose and lipid levels, improve the cardiac function, reduce the myocardial injury, and decrease the inflammatory response and oxidative stress, thus exerting the alleviating effect.

Identification of potential crucial cuproptosis-related genes in myocardial ischemia-reperfusion injury through the bioinformatic analysis

Abstract Background: Cuproptosis is known to regulate diverse physiological functions in many diseases, but its role in regulating Myocardial Ischemia-Reperfusion Injury (MI/RI) remains unclear. Methods: For this purpose, the MI/RI microarray datasets GSE61592 were downloaded from the Gene Expression Omnibus (GEO) database, and the Differently Expressed Genes (DEGs) in MI/RI were identified using R software. Moreover, the MI/RI mice model was established to confirm further the diagnostic value of Pyruvate Dehydrogenase B (Pdhb), Dihydrolipoamide S-acetyltransferase (Dlat), and Pyruvate dehydrogenase E1 subunit alpha 1 (Pdhα1). Results: The analysis of microarray datasets GSE61592 revealed that 798 genes were upregulated and 768 were downregulated in the myocardial tissue of the ischemia-reperfusion injury mice. Furthermore, Dlat, Pdhb, Pdhα1, and cuproptosis-related genes belonged to the downregulated genes. The receiver operating characteristics curve analysis results indicated that the Dlat, Pdhb, and Pdhα1 levels were downregulated in MI/RI and were found to be potential biomarkers for MI/RI diagnosis and prognosis. Similarly, analysis of Dlat, Pdhb, and Pdhα1 levels in the MI/RI mice revealed Pdhb being the key diagnostic marker. Conclusions: This study demonstrated the prognostic value of cuproptosis-related genes (Dlat, Pdhb, and Pdhα1), especially Pdhb, MI/RI, providing new insight into the MI/RI treatment.

Precondicionamiento isquémico remoto: bases de la protección y resultados clínicos / Remote ischemic preconditioning: Bases and clinical results

El precondicionamiento isquémico remoto es una manera eficaz de disminuir el daño por isquemia y reperfusión en el corazón y otros órganos como cerebro o riñón, en modelos experimentales. Este consiste en realizar entre 3 y 5 ciclos de 5 minutos de isquemia seguidos del mismo tiempo de reperfusión, en un tejido alejado del que se quiere proteger, normalmente una extremidad. Estudios preclínicos en animales indican que la isquemia precondicionante inicia señales nerviosas y humorales en el tejido isquémico remoto, que en el corazón activan mecanismos de protección. La señal nerviosa se origina en fibras sensoriales que a nivel cerebral producen una activación del sistema parasimpático. El nervio vago activa ganglios cardíacos intrínsecos del corazón lo que induce protección. Además, desde el tejido isquémico se liberan a la circulación diferentes mediadores que viajan en forma libre o en vesículas lipídicas (exosomas) que inician vías de señalización protectoras en el corazón. A pesar del éxito del precondicionamiento isquémico remoto en animales de experimentación, su aplicación en seres humanos no ha tenido resultados claros. Esta discrepancia puede deberse a una diversidad de factores tales como la edad, la existencia de otras patologías, uso de fármacos u otros tratamientos que afectan la respuesta de los pacientes. Se requiere un mayor conocimiento de las bases moleculares de este mecanismo de protección para que su aplicación en clínica sea exitosa.

In experimental models, remote ischemic preconditioning effectively decreases ischemia reperfusion injury to the heart and other organs such as the brain or kidney. It consists of 3 to 5 cycles of 5 minutes of ischemia followed by 5 minutes of reperfusion, in a remote tissue, usually a limb. Preclinical studies in animals indicate that preconditioning ischemia initiates neural and humoral signals in the remote ischemic tissue, which activate protective mechanisms in the heart. The nervous signal originates in sensory fibers that activate the parasympathetic system in the brain. The vagus nerve activates the intrinsic cardiac ganglia of the heart, leading to protection from ischemic injury. Furthermore, mediators are released from the ischemic tissue into the circulation that travels freely or in lipid vesicles (exosomes) to the heart where they initiate protective signaling pathways. Despite the success of remote ischemic preconditioning in experimental animals, its application in humans has not produced clear results. This discrepancy may be due to a variety of factors such as age, the existence of other pathologic processes, or the use of drugs or other treatments that affect the patient´s response. An increased knowledge of the molecular bases of this protective mechanism is required for its clinical application to be successful.

The Protective Effect of Nutraceuticals on Hepatic Ischemia-Reperfusion Injury in Wistar Rats.

Nutraceuticals are bioactive compounds present in foods, utilized to ameliorate health, prevent diseases, and support the proper functioning of the human body. They have gained attention due to their ability to hit multiple targets and act as antioxidants, anti-inflammatory agents, and modulators of immune response and cell death. Therefore, nutraceuticals are being studied to prevent and treat liver ischemia-reperfusion injury (IRI). This study evaluated the effect of a nutraceutical solution formed by resveratrol, quercetin, omega-3 fatty acid, selenium, ginger, avocado, leucine, and niacin on liver IRI. IRI was performed with 60 min of ischemia and 4 h of reperfusion in male Wistar rats. Afterward, the animals were euthanized to study hepatocellular injury, cytokines, oxidative stress, gene expression of apoptosis-related genes, TNF-α and caspase-3 proteins, and histology. Our results show that the nutraceutical solution was able to decrease apoptosis and histologic injury. The suggested mechanisms of action are a reduction in gene expression and the caspase-3 protein and a reduction in the TNF-α protein in liver tissue. The nutraceutical solution was unable to decrease transaminases and cytokines. These findings suggest that the nutraceuticals used favored the protection of hepatocytes, and their combination represents a promising therapeutic proposal against liver IRI.

Exercise training and experimental myocardial ischemia and reperfusion: A systematic review and meta-analysis.

Background: Despite the success of interventional coronary reperfusion strategies, morbidity and mortality from acute myocardial infarction are still substantial. Physical exercise is a well-recognized effective non-pharmacological therapy for cardiovascular diseases. Therefore, the objective of this systematic review was to analyze studies in animal models of ischemia-reperfusion in association with physical exercise protocols. Search strategy: Articles published on the topic over a 13-year period (2010-2022) were searched in two databases (PubMed and Google Scholar) using the keywords exercise training, ischemia/reperfusion or ischemia reperfusion injury. Meta-analysis and quality assessment of the studies were performed using the Review Manager 5.3 program. Results: From the 238 articles retrieved from PubMed and 200 from Google Scholar, after screening and eligibility assessment, 26 articles were included in the systematic review and meta-analysis. For meta-analysis comparing the group of previously exercised animals with the non-exercised animals and then submitted to ischemia-reperfusion, the infarct size was significantly decreased by exercise (p < 0.00001). In addition, the group exercised had increased heart-to-body weight ratio (p < 0.00001) and improved ejection fraction as measured by echocardiography (p < 0.0004) in comparison to non-exercised animals. Conclusion: We concluded that the animal models of ischemia-reperfusion indicates that exercise reduce infarct size and preserve ejection fraction, associated with beneficial myocardial remodeling.

PPAR Alpha Activation by Clofibrate Alleviates Ischemia/Reperfusion Injury in Metabolic Syndrome Rats by Decreasing Cardiac Inflammation and Remodeling and by Regulating the Atrial Natriuretic Peptide Compensatory Response.

Metabolic syndrome (MetS) is a cluster of factors that increase the risk of developing diabetes, stroke, and heart failure. The pathophysiology of injury by ischemia/reperfusion (I/R) is highly complex and the inflammatory condition plays an important role by increasing matrix remodeling and cardiac apoptosis. Natriuretic peptides (NPs) are cardiac hormones with numerous beneficial effects mainly mediated by a cell surface receptor named atrial natriuretic peptide receptor (ANPr). Although NPs are powerful clinical markers of cardiac failure, their role in I/R is still controversial. Peroxisome proliferator-activated receptor α agonists exert cardiovascular therapeutic actions; however, their effect on the NPs' signaling pathway has not been extensively studied. Our study provides important insight into the regulation of both ANP and ANPr in the hearts of MetS rats and their association with the inflammatory conditions caused by damage from I/R. Moreover, we show that pre-treatment with clofibrate was able to decrease the inflammatory response that, in turn, decreases myocardial fibrosis, the expression of metalloprotease 2 and apoptosis. Treatment with clofibrate is also associated with a decrease in ANP and ANPr expression.

Vitamin A could be a Therapeutic Agent in Ischemia/Reperfusion Induced Kidney Injury / La vitamina A podría ser un agente terapéutico en la lesión renal inducida por isquemia/reperfusión

ABSTRACT Introduction: Renal ischemia (I) could develop due to decreased or ceased blood flow to the kidney in some clinical conditions such as shock, sepsis, and kidney transplantation. The re-supply of blood to the kidney is called reperfusion (R). Ischemia and reperfusion periods can cause severe kidney damage. Objectives: When we examined the I/R molecular progression, antioxidant molecules such as vitamin A seem promising treatment agents. This study aimed to investigate the effects of vitamin A on renal I/R injury. Material and Methods: In the study, 40 Sprague-Dawley male rats were divided into five groups (n=8): the control group, only I/R, I/R+1000, I/R+3000, and I/R+9000 IU/kg of Vitamin A groups. Vitamin A was administrated to each group for seven days via oral gavage. Blood and kidney tissue samples were collected at the end of the experiment. We took blood samples for Superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), blood urea nitrogen (BUN), and creatinine (Cr) levels, and determined their values. The tissue samples were stained with hematoxylin/eosin to examine the renal changes histopathologically and stereologically under a light microscope. Results: Histopathological changes caused by I/R were decreased with vitamin A administration in a dose-dependent manner (p<0.05). Vitamin A administration decreased MDA levels and increased SOD and CAT activities (p<0.05). The most effective dose among treatment groups was 9000 IU/kg. There was no significant difference between the controls and all other groups regarding BUN and Cr concentrations. Conclusions: Consequently, administration of vitamin A after renal I/R reduced the histological damage and ameliorated the antioxidant state. These results showed that vitamin A could be a promising agent in treating I/R-induced acute kidney injury.

RESUMEN Introducción: La isquemia renal (I) puede desarrollarse debido a la disminución o interrupción del flujo sanguíneo al riñón en algunas condiciones clínicas como shock, sepsis y trasplante renal. El reabastecimiento de sangre al riñón se denomina reperfusión (R). Tanto la isquemia como los períodos de reperfusión pueden causar graves daños renales. Objetivos: Cuando examinamos la progresión molecular I/R, las moléculas antioxidantes como la vitamina A parecen agentes de tratamiento prometedores. El objetivo de este estudio fue investigar los efectos de la vitamina A sobre la lesión renal I/R. Material y Métodos: En el estudio, 40 ratas macho Sprague-Dawley se dividieron en 5 grupos (n=8) como: control, solo I/R, I/R+1000, I/R+3000 e I/R+9000 UI/kg de la Vitamina A. La vitamina A se administró a cada grupo durante 7 días por vía oral forzada. Al final del experimento se recolectaron muestras de sangre y tejido del riñón. A partir de muestras de sangre se determinaron los niveles de superóxido dismutasa (SOD), malondialdehído (MDA), catalasa (CAT), nitrógeno ureico en sangre (BUN) y creatinina (Cr). Las muestras de tejido se tiñeron con hematoxilina/eosina y los cambios en la histología renal se examinaron histopatológicamente y estereológicamente al microscopio de luz. Resultados: Los cambios histopatológicos causados por I/R disminuyeron con la administración de la vitamina A de manera dependiente de la dosis (p<0,05). La administración de la vitamina A disminuyó los niveles de MDA, aumentó las actividades de SOD y CAT (p<0,05). La dosis más eficaz entre los grupos del tratamiento fue de 9000 UI/kg. No hubo una diferencia significativa entre el grupo control y todos los demás grupos con respecto a las concentraciones de BUN y Cr. Conclusiones: Consiguientemente, la administración de la vitamina A, después de I/R renal, redujo el daño histológico y mejoró el estado antioxidante. Estos resultados mostraron que la vitamina A puede ser un agente promisorio en el tratamiento de la lesión renal aguda (LRA) inducida por I/R.