Molecular Biology of Apoptosis in Ischemia and Reperfusion

GAS5 silencing attenuates hypoxia-induced cardiomyocytes injury by targeting miR-21/PTEN

INTRODUCTION

Myocardial hypoxia is an important factor causing myocardial infarction (MI). Interestingly, many unknown factors in the molecular mechanism of MI remain unclear. Our study explored the role of lncRNA growth arrest-specific 5 (GAS5) in cell injury under hypoxia.

METHODS

AS5 expression was assessed in MI and human cardiomyocytes under hypoxia through RT-qPCR assay. Methyl thiazolyl tetrazolium assay, flow cytometry assay, and transwell assay was carried out for cell viability, cell apoptosis, cell migration, and invasion, respectively. The regulatory target of GAS5 was explored through a dual-luciferase reporter assay.

RESULTS

Our findings indicated that the upregulation of GAS5 was related to hypoxia. Downregulation of GAS5 expression could decrease hypoxia-induced cell apoptosis and increase cell migration and invasion. Moreover, GAS 5 targeted miR-21, which regulated the phosphatase and tension homology deleted on chromosome ten gene (PTEN) expression. Furthermore, the knockdown of miR-21 eliminated the effect of GAS5 silencing on cell injury.

CONCLUSION

These results indicated that lncRNA GAS5 silencing decreased cardiomyocyte injury by hypoxia-induced through regulating miR-21/PTEN.

Exosomes in Cardiovascular Disease: From Mechanism to Therapeutic Target

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality globally. In recent decades, clinical research has made significant advances, resulting in improved survival and recovery rates for patients with CVD. Despite this progress, there is substantial residual CVD risk and an unmet need for better treatment. The complex and multifaceted pathophysiological mechanisms underlying the development of CVD pose a challenge for researchers seeking effective therapeutic interventions. Consequently, exosomes have emerged as a new focus for CVD research because their role as intercellular communicators gives them the potential to act as noninvasive diagnostic biomarkers and therapeutic nanocarriers. In the heart and vasculature, cell types such as cardiomyocytes, endothelial cells, vascular smooth muscle, cardiac fibroblasts, inflammatory cells, and resident stem cells are involved in cardiac homeostasis via the release of exosomes. Exosomes encapsulate cell-type specific miRNAs, and this miRNA content fluctuates in response to the pathophysiological setting of the heart, indicating that the pathways affected by these differentially expressed miRNAs may be targets for new treatments. This review discusses a number of miRNAs and the evidence that supports their clinical relevance in CVD. The latest technologies in applying exosomal vesicles as cargo delivery vehicles for gene therapy, tissue regeneration, and cell repair are described.

Hydrogen sulfide and its donors for the treatment of cerebral ischaemia-reperfusion injury: A comprehensive review

As an endogenous gas signalling molecule, hydrogen sulfide (H₂S) is frequently present in a variety of mammals and plays a significant role in the cardiovascular and nervous systems. Reactive oxygen species (ROS) are produced in large quantities as a result of cerebral ischaemia-reperfusion, which is a very serious class of cerebrovascular diseases. ROS cause oxidative stress and induce specific gene expression that results in apoptosis. H₂S reduces cerebral ischaemia-reperfusion-induced secondary injury via anti-oxidative stress injury, suppression of the inflammatory response, inhibition of apoptosis, attenuation of cerebrovascular endothelial cell injury, modulation of autophagy, and antagonism of P2X7 receptors, and it plays an important biological role in other cerebral ischaemic injury events. Despite the many limitations of the hydrogen sulfide therapy delivery strategy and the difficulty in controlling the ideal concentration, relevant experimental evidence demonstrating that H₂S plays an excellent neuroprotective role in cerebral ischaemia-reperfusion injury (CIRI). This paper examines the synthesis and metabolism of the gas molecule H₂S in the brain as well as the molecular mechanisms of H₂S donors in cerebral ischaemia-reperfusion injury and possibly other unknown biological functions. With the active development in this field, it is expected that this review will assist researchers in their search for the potential value of hydrogen sulfide and provide new ideas for preclinical trials of exogenous H₂S.

Stem Cell Therapies for Restorative Treatments of Central Nervous System Ischemia-Reperfusion Injury

Ischemic damage to the central nervous system (CNS) is a catastrophic postoperative complication of aortic occlusion subsequent to cardiovascular surgery that can cause brain impairment and sometimes even paraplegia. Over recent years, numerous studies have investigated techniques for protecting and revascularizing the nervous system during intraoperative ischemia; however, owing to a lack of knowledge of the physiological distinctions between the brain and spinal cord, as well as the limited availability of testing techniques and treatments for ischemia-reperfusion injury, the cause of brain and spinal cord ischemia-reperfusion injury remains poorly understood, and no adequate response steps are currently available in the clinic. Given the limited ability of the CNS to repair itself, it is of great clinical value to make full use of the proliferative and differentiation potential of stem cells to repair nerves in degenerated and necrotic regions by stem cell transplantation or mobilization, thereby introducing a novel concept for the treatment of severe CNS ischemia-reperfusion injury. This review summarizes the most recent advances in stem cell therapy for ischemia-reperfusion injury in the brain and spinal cord, aiming to advance basic research and the clinical use of stem cell therapy as a promising treatment for this condition.

The potential value of exosomes as adjuvants for novel biologic local anesthetics

The side effects of anesthetic drugs are a key preoperative concern for anesthesiologists. Anesthetic drugs used for general anesthesia and regional blocks are associated with a potential risk of systemic toxicity. This prompted the use of anesthetic adjuvants to ameliorate these side effects and improve clinical outcomes. However, the adverse effects of anesthetic adjuvants, such as neurotoxicity and gastrointestinal reactions, have raised concerns about their clinical use. Therefore, the development of relatively safe anesthetic adjuvants with fewer side effects is an important area for future anesthetic drug research. Exosomes, which contain multiple vesicles with genetic information, can be released by living cells with regenerative and specific effects. Exosomes released by specific cell types have been found to have similar effects as many local anesthetic adjuvants. Due to their biological activity, carrier efficacy, and ability to repair damaged tissues, exosomes may have a better efficacy and safety profile than the currently used anesthetic adjuvants. In this article, we summarize the contemporary literature about local anesthetic adjuvants and highlight their potential side effects, while discussing the potential of exosomes as novel local anesthetic adjuvant drugs.

Renal Ischemia Tolerance Mediated by eIF5A Hypusination Inhibition Is Regulated by a Specific Modulation of the Endoplasmic Reticulum Stress

Through kidney transplantation, ischemia/reperfusion is known to induce tissular injury due to cell energy shortage, oxidative stress, and endoplasmic reticulum (ER) stress. ER stress stems from an accumulation of unfolded or misfolded proteins in the lumen of ER, resulting in the unfolded protein response (UPR). Adaptive UPR pathways can either restore protein homeostasis or can turn into a stress pathway leading to apoptosis. We have demonstrated that N1-guanyl-1,7-diamineoheptane (GC7), a specific inhibitor of eukaryotic Initiation Factor 5A (eIF5A) hypusination, confers an ischemic protection of kidney cells by tuning their metabolism and decreasing oxidative stress, but its role on ER stress was unknown. To explore this, we used kidney cells pretreated with GC7 and submitted to either warm or cold anoxia. GC7 pretreatment promoted cell survival in an anoxic environment concomitantly to an increase in xbp1 splicing and BiP level while eiF2α phosphorylation and ATF6 nuclear level decreased. These demonstrated a specific modulation of UPR pathways. Interestingly, the pharmacological inhibition of xbp1 splicing reversed the protective effect of GC7 against anoxia. Our results demonstrated that eIF5A hypusination inhibition modulates distinctive UPR pathways, a crucial mechanism for the protection against anoxia/reoxygenation.

Madder (Rubia cordifolia L.) Alleviates Myocardial Ischemia-Reperfusion Injury by Protecting Endothelial Cells from Apoptosis and Inflammation

Objective

Ischemia-reperfusion injury often occurs in organ transplantation, coronary heart disease, ischemic heart disease, and other diseases, which greatly reduces clinical efficacy. This study examined the effectiveness of madder as a medicine to treat ischemia-reperfusion injury.

Methods

The efficacy of madder was evaluated by measuring myocardial infarction size, coronary outflow volume, myocardial contraction rate, activation of inflammatory factors, autophagy factors, apoptosis factors, and related pathway genes in mice.

Results

The results indicated that treatment with madder can effectively reduce the area of myocardial infarction and restore arterial blood flow velocity and myocardial contractility in mice. Additionally, madder treatment inhibited the expression of inflammatory factors, autophagy factors, and apoptosis factors in mice and reduced the degree of myocardial cell injury. Studies have also shown that madder treatment can alleviate myocardial ischemia-reperfusion injury in mice and inhibit the occurrence of inflammatory response by inhibiting the activity of the NF-κB pathway.

Conclusion

The results showed that madder was effective against ischemia-reperfusion injury, thus showing potential as a clinical drug for treating ischemia-reperfusion injury.

Myosin 1b Participated in the Modulation of Hypoxia/Reoxygenation-Caused H9c2 Cell Apoptosis and Autophagy

Myocardial ischemia/reperfusion (I/R) injury seriously threats the health and life of patients with ischemia heart disease. Herein, we probed the potential influence of myosin 1b (myo1b) on hypoxia/reoxygenation- (H/R-) stimulated cardiomyocyte H9c2 cell apoptosis and autophagy. After H/R stimulation, the myo1b mRNA level in H9c2 cells was tested via qRT-PCR. Myo1b overexpression plasmid (OE-myo1b) and small interfering RNA (siRNA) targeting myo1b (si-myo1b) were transfected into H9c2 cells to alter myo1b expression in H9c2 cells. Following H/R stimulation and/or OE-myo1b (or si-myo1b) transfection, H9c2 cell apoptosis, proliferation, and autophagy were detected, respectively. We found that H/R stimulation reduced the mRNA level of myo1b in H9c2 cells and resulted in H9c2 cell apoptosis, proliferation inhibition, and autophagy. Overexpression of myo1b reversed the H/R-resulted H9c2 cell apoptosis, proliferation inhibition, and autophagy. Silence of myo1b had opposite effects, which promoted H9c2 cell apoptosis, reduced cell proliferation, and accelerated cell autophagy. Taken together, Myo1b took part in the modulation of H/R-stimulated cardiomyocyte apoptosis and autophagy, which might be serve as a potential endogenous target for prevention and therapy of I/R injury.

Effect of Diammonium Glycyrrhizinate in Improving Focal Cerebral Ischemia-Reperfusion Injury in Rats Through Multiple Mechanisms

OBJECTIVE

Acute ischemic stroke is a current major disabling and killer disease worldwide. We aimed to investigate the protective effect and mechanism of diammonium glycyrrhizinate in alleviating acute ischemic stroke.

METHODS

Ninety male Sprague Dawley (SD) rats (weighing 250-300 g) were randomly allocated into three groups: sham operation group (sham group), diammonium glycyrrhizinate group (DG group) and model group (model group) each with 30 individuals. A rat model of focal CIR injury was established by reversible middle cerebral artery occlusion.

RESULTS

Zea-Longa scores for the rats in the DG group and model group were 7-fold and 8-fold higher than those of the sham group 2 h post-surgery (2.90 ± 0.99 vs. 0.30 ± 0.53, P < .05; 2.80 ± 0.61 vs. 0.30 ± 0.53, P < .05, respectively). Three days after model establishment, the scores of DG group were 26.92% lower compared with those of the model group (1.90 ± 0.76 vs. 2.60 ± 0.62, P < .05). In addition, compared with the sham group, the number of Nissl bodies and Akt-positive cells in were 27.35% and 30.42% lower in the hippocampus of the DG group (Nissl bodies: 83.40 ± 7.01 vs. 115.60 ± 11.97, p < 0.05; Akt-positive cells: 94.70 ± 8.23 vs. 136.10 ± 10.37, P < .05) and 58.65% and 57.31% lower in the model group (Nissl bodies: 47.80 ± 4.91 vs. 115.60 ± 11.97, P < .05; Akt-positive cells: 58.10 ± 4.98 vs. 136.10 ± 10.37, P < 0.05), respectively. However, the number of Nissl bodies and Akt-positive cells in the hippocampus of DG group were 74.48% and 62.9% higher compared with the model group, respectively (Nissl bodies: 83.40 ± 7.01 vs. 47.80 ± 4, P < 0.05; Akt-positive cells: 94.70 ± 8.23 vs. 58.10 ± 4.98, P < .05). In addition, compared with the sham group, the number of caspase-3-positive cells, the expression level of p38 mitogen-activated protein kinase (MAPK) and the expression of matrix metallopeptidase 9 (MMP-9) were 2-fold, 34.38%, 64.78% higher in the DG group (caspase-3-positive cells: 78.70 ± 6.52 vs. 27.10 ±3.00, P < .05; p-38MAPK: 0.43 ± 0.15 vs. 0.32 ± 0.10, P < .05; MMP-9: 14.83 ± 1.18 vs. 9.00 ± 2.05, P < .05, respectively), and more than 3-fold, 1-fold and 1-fold higher in model group (caspase-3-positive cells: 121.10 ± 11.04 vs. 27.10 ± 3.00, P < .05; p-38MAPK: 0.70 ± 0.12 vs. 0.32 ± 0.10, P < .05; MMP-9: 19.00 ± 1.90 vs. 9.00 ± 2.05, P < .05), respectively. However, the number of caspase-3-positive cells and the expression levels of p-38MAPK and MMP-9 were 35.01%, 38.57% and 28.12% lower in DG group compared with the model group (caspase-3-positive cells: 78.70 ± 6.52 vs. 121.10 ± 11.04, P < .05; p-38MAPK: 0.43 ± 0.15 vs. 0.70 ± 0.12, P < .05; MMP-9: 14.83 ± 1.18 vs. 19.00 ± 1.90, P < .05).

CONCLUSIONS

Our study showed that diammonium glycyrrhizinate at 20 mg/kg/day had a protective effect on cerebral ischemia-reperfusion injury in rats by promoting formation of Nissl bodies and increasing protein expression of Akt while decreasing that of caspase-3, p38 MAPK and MMP-9, either directly or indirectly, by inhibiting apoptosis and reducing neuroinflammation. All these mechanisms resulted in improved overall neurological function.

Bioengineering exosomes for treatment of organ ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury is a leading cause of death worldwide. It arises from blood reflowing after tissue hypoxia induced by ischemia that causes severe damages due to the accumulation of reactive oxygen species and the activation of inflammatory responses. Exosomes are the smallest members of the extracellular vesicles' family, which originate from nearly all eukaryotic cells. Exosomes have a great potential in the treatment of I/R injury either in native or modified forms. Native exosomes are secreted by different cell types, such as stem cells, and contain components such as specific miRNA molecules with tissue protective properties. On the other hand, exosome bioengineering has recently received increased attention in context of current advances in the purification, manipulation, biological characterization, and pharmacological applications. There are various pre-isolation and post-isolation manipulation approaches that can be utilized to increase the circulation half-life of exosomes or the availability of their bioactive cargos in the target site. In this review, the various therapeutic actions of native exosomes in different I/R injury will be discussed first. Exosome bioengineering approaches will then be explained, including pre- and post-isolation manipulation methods, applicability for delivery of bioactive agents to injured tissue, clinical translation issues, and future perspectives.

Type 2 MI and Myocardial Injury in the Era of High-sensitivity Troponin

Troponin has been the cornerstone of the definition of MI since its introduction to clinical practice. High-sensitivity troponin has allowed clinicians to detect degrees of myocardial damage at orders of magnitude smaller than previously and is challenging the definitions of MI, with implications for patient management and prognosis. Detection and diagnosis are no doubt enhanced by the greater sensitivity afforded by these markers, but perhaps at the expense of specificity and clarity. This review focuses on the definitions, pathophysiology, prognosis, prevention and management of type 2 MI and myocardial injury. The five types of MI were first defined in 2007 and were recently updated in 2018 in the fourth universal definition of MI. The authors explore how this pathophysiological classification is used in clinical practice, and discuss some of the unanswered questions in this era of availability of high-sensitivity troponin.

Akt Inhibition as Preconditioning Treatment to Protect Kidney Cells against Anoxia

Lesions issued from the ischemia/reperfusion (I/R) stress are a major challenge in human pathophysiology. Of human organs, the kidney is highly sensitive to I/R because of its high oxygen demand and poor regenerative capacity. Previous studies have shown that targeting the hypusination pathway of eIF5A through GC7 greatly improves ischemic tolerance and can be applied successfully to kidney transplants. The protection process correlates with a metabolic shift from oxidative phosphorylation to glycolysis. Because the protein kinase B Akt is involved in ischemic protective mechanisms and glucose metabolism, we looked for a link between the effects of GC7 and Akt in proximal kidney cells exposed to anoxia or the mitotoxic myxothiazol. We found that GC7 treatment resulted in impaired Akt phosphorylation at the Ser473 and Thr308 sites, so the effects of direct Akt inhibition as a preconditioning protocol on ischemic tolerance were investigated. We evidenced that Akt inhibitors provide huge protection for kidney cells against ischemia and myxothiazol. The pro-survival effect of Akt inhibitors, which is reversible, implied a decrease in mitochondrial ROS production but was not related to metabolic changes or an antioxidant defense increase. Therefore, the inhibition of Akt can be considered as a preconditioning treatment against ischemia.

Multi-Aspect Optoacoustic Imaging of Breast Tumors under Chemotherapy with Exogenous and Endogenous Contrasts: Focus on Apoptosis and Hypoxia

Breast cancer is a complex tumor type involving many biological processes. Most chemotherapeutic agents exert their antitumoral effects by rapid induction of apoptosis. Another main feature of breast cancer is hypoxia, which may drive malignant progression and confer resistance to various forms of therapy. Thus, multi-aspect imaging of both tumor apoptosis and oxygenation in vivo would be of enormous value for the effective evaluation of therapy response. Herein, we demonstrate the capability of a hybrid imaging modality known as multispectral optoacoustic tomography (MSOT) to provide high-resolution, simultaneous imaging of tumor apoptosis and oxygenation, based on both the exogenous contrast of an apoptosis-targeting dye and the endogenous contrast of hemoglobin. MSOT imaging was applied on mice bearing orthotopic 4T1 breast tumors before and following treatment with doxorubicin. Apoptosis was monitored over time by imaging the distribution of xPLORE-APOFL750©, a highly sensitive poly-caspase binding apoptotic probe, within the tumors. Oxygenation was monitored by tracking the distribution of oxy- and deoxygenated hemoglobin within the same tumor areas. Doxorubicin treatment induced an increase in apoptosis-depending optoacoustic signal of xPLORE-APOFL750© at 24 h after treatment. Furthermore, our results showed spatial correspondence between xPLORE-APO750© and deoxygenated hemoglobin. In vivo apoptotic status of the tumor tissue was independently verified by ex vivo fluorescence analysis. Overall, our results provide a rationale for the use of MSOT as an effective tool for simultaneously investigating various aspects of tumor pathophysiology and potential effects of therapeutic regimes based on both endogenous and exogenous molecular contrasts.

Novel Role of miR-18a-5p and Galanin in Rat Lung Ischemia Reperfusion-Mediated Response

Lung ischemia reperfusion (IR) is known to occur after lung transplantation or cardiac bypass. IR leads to tissue inflammation and damage and is also associated with increased morbidity and mortality. Various receptors are known to partake in activation of the innate immune system, but the downstream mechanism of tissue damage and inflammation is yet unknown. MicroRNAs (miRNAs) are in the forefront in regulating ischemia reperfusion injury and are involved in inflammatory response. Here, we have identified by high-throughput approach and evaluated a distinct set of miRNAs that may play a role in response to IR in rat lung tissue. The top three differentially expressed miRNAs were validated through quantitative PCRs in the IR rat lung model and an in vitro model of IR of hypoxia and reoxygenation exposed type II alveolar cells. Among the miRNAs, miR-18a-5p showed consistent downregulation in both the model systems on IR. Cellular and molecular analysis brought to light a crucial role of this miRNA in ischemia reperfusion. miR-18a-5p plays a role in IR-mediated apoptosis and ROS production and regulates the expression of neuropeptide Galanin. It also influences the nuclear localization of transcription factor: nuclear factor-erythroid 2-related factor (Nrf2) which in turn may regulate the expression of the miR-18a gene. Thus, we have not only established a rat model for lung IR and enumerated the important miRNAs involved in IR but have also extensively characterized the role of miR-18a-5p. This study will have important clinical and therapeutic implications for and during transplantation procedures.

Ethyl pyruvate: A newly discovered compound against ischemia-reperfusion injury in multiple organs

Ischemia-reperfusion injury (IRI) is a process whereby an initial ischemia injury and subsequent recovery of blood flow, which leads to the propagation of an innate immune response and the changes of structural and functional of multiple organs. Therefore, IRI is considered to be a great challenge in clinical treatment such as organ transplantation or coronary angioplasty. In recent years, ethyl pyruvate (EP), a derivative of pyruvate, has received great attention because of its stability and low toxicity. Previous studies have proved that EP has various pharmacological activities, including anti-inflammation, anti-oxidative stress, anti-apoptosis, and anti-fibrosis. Compelling evidence has indicated EP plays a beneficial role in a variety of acute injury models, such as brain IRI, myocardial IRI, renal IRI, and hepatic IRI. Moreover, EP can not only effectively inhibit multiple IRI-induced pathological processes, but also improve the structural and functional lesion of tissues and organs. In this study, we review the recent progress in the research on EP and discuss their implications for a better understanding of multiple organ IRI, and the prospects of targeting the EP for therapeutic intervention.

The Composite of 3, 4-Dihydroxyl-Phenyl Lactic Acid and Notoginsenoside R1 Attenuates Myocardial Ischemia and Reperfusion Injury Through Regulating Mitochondrial Respiratory Chain

Aim

3,4-Dihydroxyl-phenyl lactic acid (DLA) and notoginsenoside R1 (R1) are known to protect ischemia and reperfusion (I/R) injury by targeting Sirtuin1/NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 10/the Mitochondrial Complex I (Sirt-1/NDUFA10/Complex I) and Rho-associated kinase/adenosine triphosphate (ROCK/ATP) ATP synthase δ subunit (ATP 5D), respectively. We hypothesized that a composite of the two may exhibit a more potent effect on I/R injury. The study was designed to test this hypothesis.

Materials and Methods

Male Sprague–Dawley rats underwent left anterior descending artery occlusion and reperfusion, with or without DLA, R1, or a combination of 3,4-dihydroxyl-phenyl lactic acid and notoginsenoside R1 (DR) pretreatment. Heart function, myocardial morphology, myocardial infarct, myocardial blood flow (MBF), apoptosis, vascular diameter, and red blood cell (RBC) velocity in venules were evaluated. Myeloperoxidase (MPO), malondialdehyde (MDA), and 8-oxo-deoxyguanosine (8-OHdG) were assessed. The content of ATP, adenosine diphosphate (ADP), and adenosine monophosphate (AMP), the activity of mitochondrial respiratory chain Complex I and its subunit NDUFA10, the Mitochondrial Complex V (Complex V) and its subunit ATP 5D, Sirt-1, Ras homolog gene family, member A (RhoA), ROCK-1, and phosphorylated myosin light chain (P-MLC) were evaluated. R1 binding to Sirt-1 was determined by surface plasmon resonance.

Results

DLA inhibited the expression of Sirt-1, the reduction in Complex I activity and its subunit NDUFA10 expression, the increase in MPO, MDA, and 8-OhdG, and apoptosis. R1 inhibited the increase in the expression of RhoA/ROCK-1/P-MLC, the reduction of Complex V activity and its subunit ATP 5D expression, alleviated F-actin, and myocardial fiber rupture. Both DLA and R1 reduced the myocardial infarction size, increased the velocities of RBC in venules, and improved MBF and heart function impaired by I/R. DR exhibited effects similar to what was exerted, respectively, by DLA and R1 in terms of respiratory chain complexes and related signaling and outcomes, and an even more potent effect on myocardial infarct size, RBC velocity, heart function, and MBF than DLA and R1 alone.

Conclusion

A combination of 3,4-dihydroxyl-phenyl lactic acid and notoginsenoside R1 revealed a more potent effect on I/R injury via the additive effect of DLA and R1, which inhibited not only apoptosis caused by low expression of Sirt-1/NDUFA10/Complex I but also myocardial fiber fracture caused by RhoA/ROCK-1 activation and decreased expression of ATP/ATP 5D/Complex V.

Effect of NAD+ boosting on kidney ischemia-reperfusion injury

Acute kidney injury (AKI) is associated with a very high mortality and an increased risk for progression to chronic kidney disease (CKD). Ischemia-reperfusion injury (IRI) is a model for AKI, which results in tubular damage, dysfunction of the mitochondria and autophagy, and in decreased cellular nicotinamide adenine dinucleotide (NAD⁺) with progressing fibrosis resulting in CKD. NAD⁺ is a co-enzyme for several proteins, including the NAD⁺ dependent sirtuins. NAD⁺ augmentation, e.g. by use of its precursor nicotinamide riboside (NR), improves mitochondrial homeostasis and organismal metabolism in many species. In the present investigation the effects of prophylactic administration of NR on IRI-induced AKI were studied in the rat. Bilateral IRI reduced kidney tissue NAD⁺, caused tubular damage, reduced α-Klotho (klotho), and altered autophagy flux. AKI initiated progression to CKD, as shown by induced profibrotic Periostin (postn) and Inhibin subunit beta-A, (activin A / Inhba), both 24 hours and 14 days after surgery. NR restored tissue NAD⁺ to that of the sham group, increased autophagy (reduced p62) and sirtuin1 (Sirt1) but did not ameliorate renal tubular damage and profibrotic genes in the 24 hours and 14 days IRI models. AKI induced NAD⁺ depletion and impaired autophagy, while augmentation of NAD⁺ by NR restored tissue NAD⁺ and increased autophagy, possibly serving as a protective response. However, prophylactic administration of NR did not ameliorate tubular damage of the IRI rats nor rescued the initiation of fibrosis in the long-term AKI to CKD model, which is a pivotal event in CKD pathogenesis.

New Insights Into the Role of Autophagy in Liver Surgery in the Setting of Metabolic Syndrome and Related Diseases

Visceral obesity is an important component of metabolic syndrome, a cluster of diseases that also includes diabetes and insulin resistance. A combination of these metabolic disorders damages liver function, which manifests as non-alcoholic fatty liver disease (NAFLD). NAFLD is a common cause of abnormal liver function, and numerous studies have established the enormously deleterious role of hepatic steatosis in ischemia-reperfusion (I/R) injury that inevitably occurs in both liver resection and transplantation. Thus, steatotic livers exhibit a higher frequency of post-surgical complications after hepatectomy, and using liver grafts from donors with NAFLD is associated with an increased risk of post-surgical morbidity and mortality in the recipient. Diabetes, another MetS-related metabolic disorder, also worsens hepatic I/R injury, and similar to NAFLD, diabetes is associated with a poor prognosis after liver surgery. Due to the large increase in the prevalence of MetS, NAFLD, and diabetes, their association is frequent in the population and therefore, in patients requiring liver resection and in potential liver graft donors. This scenario requires advancement in therapies to improve postoperative results in patients suffering from metabolic diseases and undergoing liver surgery; and in this sense, the bases for designing therapeutic strategies are in-depth knowledge about the molecular signaling pathways underlying the effects of MetS-related diseases and I/R injury on liver tissue. A common denominator in all these diseases is autophagy. In fact, in the context of obesity, autophagy is profoundly diminished in hepatocytes and alters mitochondrial functions in the liver. In insulin resistance conditions, there is a suppression of autophagy in the liver, which is associated with the accumulation of lipids, being this is a risk factor for NAFLD. Also, oxidative stress occurring in hepatic I/R injury promotes autophagy. The present review aims to shed some light on the role of autophagy in livers undergoing surgery and also suffering from metabolic diseases, which may lead to the discovery of effective therapeutic targets that could be translated from laboratory to clinical practice, to improve postoperative results of liver surgeries when performed in the presence of one or more metabolic diseases.

Targeting oxidative stress, a crucial challenge in renal transplantation outcome

Disorders characterized by ischemia/reperfusion (I/R) are the most common causes of debilitating diseases and death in stroke, cardiovascular ischemia, acute kidney injury or organ transplantation. In the latter example the I/R step defines both the amplitude of the damages to the graft and the functional recovery outcome. During transplantation the kidney is subjected to blood flow arrest followed by a sudden increase in oxygen supply at the time of reperfusion. This essential clinical protocol causes massive oxidative stress which is at the basis of cell death and tissue damage. The involvement of both reactive oxygen species (ROS) and nitric oxides (NO) has been shown to be a major cause of these cellular damages. In fact, in non-physiological situations, these species escape endogenous antioxidant control and dangerously accumulate in cells. In recent years, the objective has been to find clinical and pharmacological treatments to reduce or prevent the appearance of oxidative stress in ischemic pathologies. This is very relevant because, due to the increasing success of organ transplantation, clinicians are required to use limit organs, the preservation of which against oxidative stress is crucial for a better outcome. This review highlights the key actors in oxidative stress which could represent new pharmacological targets.

Upregulation of miR-499a-5p Decreases Cerebral Ischemia/Reperfusion Injury by Targeting PDCD4

MiR-499a-5p was significantly downregulated in degenerative tissues and correlated with apoptosis. Nonetheless, the biological function of miR-499a-5p in acute ischemic stroke has been still unclear. In this study, we found that the plasma levels of miR-499a-5p were significantly downregulated in 64 ischemic stroke patients and negatively correlated with the National Institutes of Health Stroke Scale score. Then, we constructed cerebral ischemia/reperfusion (I/R) injury in rats after middle cerebral artery occlusion and subsequent reperfusion and oxygen-glucose deprivation and reoxygenation (OGD/R)-treated SH-SY5Y cell model. Transfection with miR-499a-5p mimic was accomplished by intracerebroventricular injection in the in vivo I/R injury model. We further found that miR-499a-5p overexpression decreased infarct volumes and cell apoptosis in the in vivo I/R stroke model using TTC and TUNEL staining. PDCD4 was a direct target of miR-499a-5p by luciferase report assay and Western blotting. Knockdown of PDCD4 reduced the infarct damage and cortical neuron apoptosis caused by I/R injury. MiR-499a-5p exerted neuroprotective roles mainly through inhibiting PDCD4-mediated apoptosis by CCK-8 assay, LDH release assay, and flow cytometry analysis. These findings suggest that miR-499a-5p might represent a novel target that regulates brain injury by inhibiting PDCD4-mediating apoptosis.

Targeting TFE3 Protects Against Lysosomal Malfunction-Induced Pyroptosis in Random Skin Flaps via ROS Elimination

Increasing evidence indicates that pyroptosis, a new type of programmed cell death, may participate in random flap necrosis and play an important role. ROS-induced lysosome malfunction is an important inducement of pyroptosis. Transcription factor E3 (TFE3) exerts a decisive effect in oxidative metabolism and lysosomal homeostasis. We explored the effect of pyroptosis in random flap necrosis and discussed the effect of TFE3 in modulating pyroptosis. Histological analysis via hematoxylin-eosin staining, immunohistochemistry, general evaluation of flaps, evaluation of tissue edema, and laser Doppler blood flow were employed to determine the survival of the skin flaps. Western blotting, immunofluorescence, and enzyme-linked immunosorbent assays were used to calculate the expressions of pyroptosis, oxidative stress, lysosome function, and the AMPK-MCOLN1 signaling pathway. In cell experiments, HUVEC cells were utilized to ensure the relationship between TFE3, reactive oxygen species (ROS)-induced lysosome malfunction and cell pyroptosis. Our results indicate that pyroptosis exists in the random skin flap model and oxygen and glucose deprivation/reperfusion cell model. In addition, NLRP3-mediated pyroptosis leads to necrosis of the flaps. Moreover, we also found that ischemic flaps can augment the accumulation of ROS, thereby inducing lysosomal malfunction and finally initiating pyroptosis. Meanwhile, we observed that TFE3 levels are interrelated with ROS levels, and overexpression and low expression of TFE3 levels can, respectively, inhibit and promote ROS-induced lysosomal dysfunction and pyroptosis during in vivo and in vitro experiments. In conclusion, we found the activation of TFE3 in random flaps is partially regulated by the AMPK-MCOLN1 signal pathway. Taken together, TFE3 is a key regulator of ROS-induced pyroptosis in random skin flaps, and TFE3 may be a promising therapeutic target for improving random flap survival.

Metabotropic Glutamate Receptor Blockade Reduces Preservation Damage in Livers from Donors after Cardiac Death

We previously demonstrated that the blockade of mGluR5 by 2-methyl-6(phenylethynyl)pyridine (MPEP) reduces both cold and warm ischemia/reperfusion injury. Here we evaluated whether MPEP reduces the hepatic preservation injury in rat livers from cardiac-death-donors (DCDs). Livers from DCD rats were isolated after an in situ warm ischemia (30 min) and preserved for 22 h at 4 °C with UW solution. Next, 10 mg/Kg MPEP or vehicle were administered 30 min before the portal clamping and added to the UW solution (3 µM). LDH released during washout was quantified. Liver samples were collected for iNOS, eNOS, NO, TNF-α, ICAM-1, caspase-3 and caspase-9 protein expression and nuclear factor-erythroid-2-related factor-2 (Nrf2) gene analysis. Lower LDH levels were detected in control grafts versus DCD groups. An increase in eNOS and NO content occurred after MPEP treatment; iNOS and TNF-α content was unchanged. ICAM-1 expression was reduced in the MPEP-treated livers as well as the levels of caspase-3 and caspase-9. Nrf2, oxidative stress-sensitive gene, was recovered to control value by MPEP. These results suggest that MPEP can be used to reclaim DCD livers subjected to an additional period of cold ischemia during hypothermic storage. MPEP protects against apoptosis and increased eNOS, whose overexpression has been previously demonstrated to be protective in hepatic ischemia/reperfusion damage.

The Effect of Allograft Transplantation of Sertoli Cell on Expression of NF-кB, Bax Proteins, and Ischemic Tolerance in Rats with Focal Cerebral Ischemia

One of the newest methods to reduce cerebral ischemia damages is cell therapy. The aim of this study is to evaluate the effect of Sertoli cell transplantation on ischemia-induced injuries in animal models of stroke. Rats were divided into four groups: transplant+ischemia, ischemia, sham, and control. Sertoli cells were separated from the other testis of rats and cultured. Unilateral Sertoli cell transplantation was performed in the right striatum by using stereotaxic surgery. For induction of brain ischemia, middle cerebral artery occlusion surgery was used 14 days after transplantation. By using western blotting method, expression of nuclear factor kappa (NF-кB) and Bax were evaluated. In this study, a remarkable decrease in neurological deficits, infection, blood-brain barrier permeability, and brain edema was observed in the cell transplant recipient group in comparison with the ischemia group. Probably, a reduction in inflammation (NF-кB factor) and apoptosis (Bax) following injection of Sertoli cells result in amelioration of ischemic damages induced by MCAO surgery.

Knockdown lncRNA NEAT1 regulates the activation of microglia and reduces AKT signaling and neuronal apoptosis after cerebral ischemic reperfusion

Acute cerebral ischaemia may lead to serious consequences, including brain injury caused by uncontrolled reperfusion, which occurs when circulation is re-established. The long non-coding RNA (lncRNA) nuclear enriched abundant transcript 1 (NEAT1) plays an important role in the immune system. However, the potential roles and underlying molecular mechanisms of NEAT1 in cerebral ischaemia/reperfusion (I/R) injury remain unclear. The aim of the present study was to investigate the function of the lncRNA NEAT1 in cerebral I/R injury and its potential beneficial effects on neurons. In our study, oxygen-glucose deprivation (OGD)/reoxygenation (OGD/R) was induced in vitro to mimic cerebral I/R injury. Cholecystokinin-octopeptide (CCK-8) was used to measure cell viability, and flow cytometry was used to measure cell apoptosis. Real-time quantitative PCR (qRT-PCR) was used to measure the expression of phenotypic markers of classically activated (M1) and alternatively activated (M2) microglia, and western blotting was performed to detect the levels of proteins related to the AKT/STAT3 pathway. The expression of the lncRNA NEAT1 was significantly upregulated in patients with ischaemic stroke, and knockdown of the lncRNA NEAT1 alleviated OGD/R-induced apoptosis and increased neuronal viability. Furthermore, the lncRNA NEAT1 may inhibit microglial polarization towards the M1 phenotype to reduce the damage caused by OGD/R and reduce the activity of the AKT/STAT3 pathway. In conclusion, the lncRNA NEAT1 may be a potential target for new therapeutic interventions for cerebral I/R.

Attenuation of the Na/K‑ATPase/Src/ROS amplification signaling pathway by astaxanthin ameliorates myocardial cell oxidative stress injury

The 3S, 3′S-ASTaxanthin (3S, 3′S-AST) isomer has strong antioxidant activity; however, its protective roles and potential mechanisms against oxidative stress damage in cardiomyocytes have not been investigated. Na⁺/K⁺-ATPase (NKA)/Src signal activation has an important role in increasing reactive oxygen species (ROS) production. The aim of the present study was to investigate the protective effects and mechanism of 3S, 3′S-AST on hydrogen peroxide (H₂O₂)-induced oxidative stress injury in H9c2 myocardial cells. The protective effects of 3S, 3′S-AST on H₂O₂-induced H9c2 cell injury was observed by measuring lactate dehydrogenase and creatine kinase myocardial band content, cell viability and nuclear morphology. The antioxidant effect was investigated by analyzing ROS accumulation and malondialdehyde, glutathione (GSH) peroxidase, GSH and glutathione reductase activity levels. The protein expression levels of Bax, Bcl-2, caspase-3 and cleaved caspase-3 were analyzed using western blotting to determine cardiomyocyte apoptosis. Western blot analysis of the phosphorylation levels of Src and Erk1/2 were also performed to elucidate the molecular mechanism involved. The results showed that 3S, 3′S-AST reduced the release of LDH and promoted cell viability, and attenuated ROS accumulation and cell apoptosis induced by H₂O₂. Furthermore, 3S, 3′S-AST also restored apoptosis-related Bax and Bcl-2 protein expression levels in H₂O₂-treated H9c2 cells. The phosphorylation levels of Src and Erk1/2 were significantly higher in the H₂O₂ treatment group, whereas 3S, 3′S-AST pretreatment significantly decreased the levels of phosphorylated (p)-Src and p-ERK1/2. The results provided evidence that 3S, 3′S-AST exhibited a cardioprotective effect against oxidative stress injury by attenuating NKA/Src/Erk1/2-modulated ROS amplification.

Assessment of Ankaferd Blood Stopper in experimental liver ischemia reperfusion injury

Background/aim

To investigate possible protective effects of Ankaferd Blood Stopper® (ABS) in an experimental liver ischemia reperfusion injury (IRI) model.

Materials and methods

The study was carried out on 30 female rats separated into 3 groups as sham, control (IRI), and treatment (IRI + ABS) groups. In the IRI + ABS group, 0.5 mL/day ABS was given for 7 days before surgery. In the IRI and IRI + ABS groups, the hepatic pedicle was clamped for 30 min to apply ischemia. Then, after opening the clamp, 90-min reperfusion of the liver was provided. Blood and liver tissue samples were taken for biochemical and histopathological analyses.

Results

Compared to the sham group, the IRI group had significantly higher levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total oxidant status (TOS), malondialdehyde (MDA), fluorescent oxidant products (FOP) and lower expression of albumin and total antioxidant status (TAS) (P < 0.05). Compared to the IRI group, the IRI+ABS group showed lower expression of AST, ALT, TOS, MDA and FOP and higher expression of albumin and TAS (P < 0.05). In the histopathological analysis, congestion scores were statistically significantly lower in the IRI + ABS group than in the IRI group.

Conclusions

ABS has a strong hepatoprotective effect due to its antioxidant and antiinflammatory effects and could therefore be used as a potential therapeutic agent for IRI.

MiR-181d-5p Targets KLF6 to Improve Ischemia/Reperfusion-Induced AKI Through Effects on Renal Function, Apoptosis, and Inflammation

Renal tubular epithelial cell (RTEC) death and renal interstitial inflammation are the most crucial pathophysiological changes in acute kidney ischemia/reperfusion injury (IRI). The microRNA (miR)-181d family plays diverse roles in cell proliferation, apoptosis and inflammation, but its renal target and potential role in IRI are unknown. Here, we showed that the expression of miR-181d-5p decreased and Krueppel-like factor 6 (KLF6) increased in a renal cell (HK-2) model of hypoxia/reoxygenation (H/R) injury and a mouse model of renal IRI. They were mainly distributed in the renal tubules. After renal IRI, miR-181d-5p overexpression significantly inhibited inflammatory mediators, reduced apoptosis and further improved renal function. KLF6 exacerbated RTEC damage and acted as a NF-κB co-activator to aggravate the renal IRI inflammatory response. Mechanistically, KLF6 was predicted as a new potential target gene of miR-181d-5p through bioinformatic analysis and luciferase reporter assay verification. After overexpressing miR-181d-5p and inhibiting KLF6, the role of miR-181d-5p was weakened on the renal damage improvement. In conclusion, miR-181d-5p upregulation produced protective antiapoptotic and anti-inflammatory effects against IRI in kidneys in vivo and H/R injury in HK-2 cells in vitro, and these effects were achieved by targeted inhibition of KLF6. Thus, our results provide novel insights into the molecular mechanisms associated with IRI and a potential novel therapeutic target.

Cell Death Pathways in Ischemic Stroke and Targeted Pharmacotherapy

Ischemic stroke is one of the significant causes of morbidity and mortality, affecting millions of people across the globe. Cell injury in the infarct region is an inevitable consequence of focal cerebral ischemia. Subsequent reperfusion exacerbates the harmful effect and increases the infarct volume. These cellular injuries follow either a regulated pathway involving tightly structured signaling cascades and molecularly defined effector mechanisms or a non-regulated pathway, also known as accidental cell death, where the process is biologically uncontrolled. Classical cell death pathways are long established and well reported in several articles that majorly define apoptotic cell death. A recent focus on cell death study also considers investigation on non-classical pathways that are tightly regulated, may or may not involve caspases, but non-apoptotic. Pathological cell death is a cardinal feature of different neurodegenerative diseases. Although ischemia cannot be classified as a neurodegenerative disease, it is a cerebrovascular event where the infarct region exhibits aberrant cell death. Over the past few decades, several therapeutic options have been implicated for ischemic stroke. However, their use has been hampered owing to the number of limitations that they possess. Ischemic penumbral neurons undergo apoptosis and become dysfunctional; however, they are salvageable. Thus, understanding the role of different cell death pathways is crucial to aid in the modern treatment of protecting apoptotic neurons.

Proteomics Analysis for Identification of Potential Cell Signaling Pathways and Protein Targets of Actions of Atractylodin and β-Eudesmol Against Cholangiocarcinoma

Objective:

The study aimed to identify potential cell signaling pathways and protein targets of actions of atractylodin and β-eudesmol in cholangiocarcinoma, the two active compounds isolated from Atracylodes lancea using proteomics approach.

Method:

The cholangiocarcinoma cell line, CL-6, was treated with each compound for 3 and 6 hours, and the proteins from both intra- and extracellular components were extracted. LC-MS/MS was applied following the separation of the extract proteins by SDS-PAGE and digestion with trypsin. Signaling pathways and protein expression were analyzed by MASCOT and STITCH software.

Results:

A total of 4,323 and 4,318 proteins were identified from intra- and extracellular components, respectively. Six and 4 intracellular proteins were linked with the signaling pathways (apoptosis, cell cycle control, and PI3K-AKT) of atractylodin and β-eudesmol, respectively. Four and 3 extracellular proteins were linked with the signaling pathways (NF-κB and PI3K-AKT) of atractylodin and β-eudesmol, respectively.

Conclusion:

In conclusion, a total of 17 proteins associated with four cell signaling pathways that could be potential molecular targets of anticholangiocarcinoma action of atractylodin and β-eudesmol were identified through the application of proteomics approach.

Inducible Nitric Oxide Synthase and L-Arginine Optimizes Nitric Oxide Bioavailability in Ischemic Tissues Under Diabetes Mellitus Type 1

BACKGROUND

The mechanisms influencing the balance of nitric oxide (NO) bioavailability in tissues are negatively affected under diabetic and also under ischemic conditions. Free tissue transplantation for diabetic patients has to deal with both ischemic and diabetic circumstances, which lead to a significantly decrease in providing NO, thus increasing ischemia-reperfusion injury. In previous studies, we could prove that enhancing NO bioavailability leads to attenuated ischemia-reperfusion injury macrocirculatory and microcirculatory alterations in healthy and also in diabetes type 2 rats. This study is evaluating the role of inducible nitric oxide synthase in different dosages and L-arginine under diabetes type 1 conditions.

METHODS

Diabetic type 1 conditions were established via streptozotocin over a period of 4 weeks and verified via blood sugar, insulin, and C-peptide levels. Vascular pedicle isolated rat skin flap model that underwent 3 hours of ischemia was used. At 30 minutes before ischemia, normal saline, inducible nitric oxide synthase (NOS) (1/2 IE), and L-arginine (50 mg/kg body weight) were administered systemically. Ischemia/reperfusion (I/R)-induced alterations were measured 5 days after the operation.

RESULTS

The inducible NOS (iNOS) attenuated I/R-induced alterations under diabetic type 1 conditions significantly with vitality rates of 16.1% compared with control group (5.5%). Best results could be achieved with the combination of iNOS (1 IE) and L-arginine displaying vitality rates of 43%. Increased dosage of inducible nitric oxide (2 IE) led to decreased vitality rates (22.2%/27.4% without/with L-arginine).

CONCLUSIONS

Supporting the mechanisms of NO bioavailability via exogenous application of iNOS and L-arginine significantly attenuated I/R-induced alterations in a skin flap rat model. This pharmacologic preconditioning could be an easy and effective interventional strategy to uphold conversation of L-arginine to NO even on ischemic and type 1 diabetic conditions.

Combined Cyclosporin A and Hypothermia Treatment Inhibits Activation of BV-2 Microglia but Induces an Inflammatory Response in an Ischemia/Reperfusion Hippocampal Slice Culture Model

Introduction

Hypothermia attenuates cerebral ischemia-induced neuronal cell death associated with neuroinflammation. The calcineurin inhibitor cyclosporin A (CsA) has been shown to be neuroprotective by minimizing activation of inflammatory pathways. Therefore, we investigated whether the combination of hypothermia and treatment with CsA has neuroprotective effects in an oxygen-glucose deprivation/reperfusion (OGD/R) injury model in neuronal and BV-2 microglia monocultures, as well as in an organotypic hippocampal slice culture (OHSC).

Methods

Murine primary neurons, BV-2 microglia, and OHSC were pretreated with CsA and exposed to 1 h OGD (0.2% O₂) followed by reperfusion at normothermia (37°C) or hypothermia (33.5°C). Cytotoxicity was measured by lactate dehydrogenase and glutamate releases. Damage-associated molecular patterns (DAMPs) high mobility group box 1 (HMGB1), heat shock protein 70 (Hsp70), and cold-inducible RNA-binding protein (CIRBP) were detected in cultured supernatant by western blot analysis. Interleukin-6 (IL-6), Interleukin-1α and -1β (IL-1α/IL1-β), tumor necrosis factor-α (TNF-α), monocyte chemotactic protein 1 (MCP1), inducible nitric oxide synthase (iNOS), glia activation factors ionized calcium-binding adapter molecule 1 (Iba1), and transforming growth factor β1 (TGF-β1) gene expressions were analyzed by RT-qPCR.

Results

Exposure to OGD plus 10 μM CsA was sufficient to induce necrotic cell death and subsequent release of DAMPs in neurons but not BV-2 microglia. Moreover, OGD/R-induced secondary injury was also observed only in the neurons, which was not attenuated by cooling and no increased toxicity by CsA was observed. BV-2 microglia were not sensitive to OGD/R-induced injury but were susceptible to CsA-induced toxicity in a dose dependent manner, which was minimized by hypothermia. CsA attenuated IL-1β and Iba1 expressions in BV-2 microglia exposed to OGD/R. Hypothermia reduced IL-1β and iNOS expressions but induced TNF-α and Iba1 expressions in the microglia. However, these observations did not translate to the ex vivo OHCS model, as general high expressions of most cytokines investigated were observed.

Conclusion

Treatment with CsA has neurotoxic effects on primary neurons exposed to OGD but could inhibit BV-2 microglia activation. However, CsA and hypothermia treatment after ischemia/reperfusion injury results in cytotoxic neuroinflammation in the complex ex vivo OHSC.

Mitogen Activated Protein Kinases in Steatotic and Non-Steatotic Livers Submitted to Ischemia-Reperfusion

We analyzed the participation of mitogen-activated protein kinases (MAPKs), namely p38, JNK and ERK 1/2 in steatotic and non-steatotic livers undergoing ischemia-reperfusion (I-R), an unresolved problem in clinical practice. Hepatic steatosis is a major risk factor in liver surgery because these types of liver tolerate poorly to I-R injury. Also, a further increase in the prevalence of steatosis in liver surgery is to be expected. The possible therapies based on MAPK regulation aimed at reducing hepatic I-R injury will be discussed. Moreover, we reviewed the relevance of MAPK in ischemic preconditioning (PC) and evaluated whether MAPK regulators could mimic its benefits. Clinical studies indicated that this surgical strategy could be appropriate for liver surgery in both steatotic and non-steatotic livers undergoing I-R. The data presented herein suggest that further investigations are required to elucidate more extensively the mechanisms by which these kinases work in hepatic I-R. Also, further researchers based in the development of drugs that regulate MAPKs selectively are required before such approaches can be translated into clinical liver surgery.

Suppression of long noncoding RNA TTTY15 attenuates hypoxia-induced cardiomyocytes injury by targeting miR-455-5p

Myocardial infarction (MI) is a severe heart disease caused by acute, persistent ischemia or hypoxia and finally leads to heart failure and sudden death. However, the intrinsic molecular mechanisms of MI remain largely unknown. lncRNAs have also been implicated in the process of ischemic heart diseases. However, the role of lncRNA TTTY15 in MI is not elucidated. We evaluated the expression of TTTY15 in MI and human cardiomyocyte under hypoxia. We explored the role of TTTY15 in cell injury under hypoxia. We searched for potential target of TTTY15. Up-regulation of TTTY15 was associated with hypoxia. Silencing TTTY15 prevented hypoxia-induced cell apoptosis and rescued the cell migration and invasion. TTTY15 targeted miR-455-5p, which regulated the Jun dimerization protein 2 (JDP2) expression. Knocking down miR-455-5p abolished effects of TTTY-15 silencing on cell injury. Suppression of long noncoding RNA TTTY15 attenuates hypoxia-induced cardiomyocytes injury by targeting miR-455-5p.

Autophagy: novel insights into therapeutic target of electroacupuncture against cerebral ischemia/ reperfusion injury

Electroacupuncture is known as an effective adjuvant therapy in ischemic cerebrovascular disease. However, its underlying mechanisms remain unclear. Studies suggest that autophagy, which is essential for cell survival and cell death, is involved in cerebral ischemia reperfusion injury and might be modulate by electroacupuncture therapy in key ways. This paper aims to provide novel insights into a therapeutic target of electroacupuncture against cerebral ischemia/reperfusion injury from the perspective of autophagy. Here we review recent studies on electroacupuncture regulation of autophagy-related markers such as UNC-51-like kinase-1 complex, Beclin1, microtubule-associated protein-1 light chain 3, p62, and autophagosomes for treating cerebral ischemia/reperfusion injury. The results of these studies show that electroacupuncture may affect the initiation of autophagy, vesicle nucleation, expansion and maturation of autophagosomes, as well as fusion and degradation of autophagolysosomes. Moreover, studies indicate that electroacupuncture probably modulates autophagy by activating the mammalian target of the rapamycin signaling pathway. This review thus indicates that autophagy is a therapeutic target of electroacupuncture treatment against ischemic cerebrovascular diseases.

Gene Silencing With siRNA (RNA Interference): A New Therapeutic Option During Ex Vivo Machine Liver Perfusion Preservation

RNA interference (RNAi) is a natural process of posttranscriptional gene regulation that has raised a lot of attention culminating with the Nobel Prize in Medicine in 2006. RNAi-based therapeutics have been tested in experimental transplantation to reduce ischemia/reperfusion injury (IRI) with success. Modulation of genes of the innate immune system, as well as apoptotic genes, and those involved in the nuclear factor kappa B pathways can reduce liver injury in rodent liver pedicle clamping and transplantation models of IRI. However, in vivo use of RNAi faces limitations regarding the method of administration, uptake, selectivity, and stability. Machine perfusion preservation, a more recent alternative approach for liver preservation showing superior results to static cold preservation, could be used as a platform for gene interference therapeutics. Our group was the first to demonstrate uptake of small interfering RNA (siRNA) during liver machine preservation under both normothermic and hypothermic perfusion. Administering siRNA in the perfusion solution during ex vivo machine preservation has several advantages, including more efficient delivery, lower doses and cost-saving, and none/fewer side effects to other organs. Recently, the first RNAi drug was approved by the US Food and Drug Administration for clinical use, opening a new avenue for new drugs with different clinical applications. RNAi has the potential to have transformational therapeutic applications in several areas of medicine including transplantation. We believe that machine preservation offers great potential to be the ideal delivery method of siRNA to the liver graft, and future studies should be initiated to improve the clinical applicability of RNAi in solid organ transplantation.

Revascularization and endothelial progenitor cells in stroke

Stroke is one of the leading causes of death and disability worldwide. Tremendous improvements have been achieved in the acute care of stroke patients with the implementation of stroke units, thrombolytic drugs, and endovascular trombectomies. However, stroke survivors with neurological deficits require long periods of neurorehabilitation, which is the only approved therapy for poststroke recovery. With this scenario, more treatments are urgently needed, and only the understanding of the mechanisms of brain recovery might contribute to identify new therapeutic agents. Fortunately, brain injury after stroke is counteracted by the birth and migration of several populations of progenitor cells towards the injured areas, where angiogenesis and vascular remodeling play a key role providing trophic support and guidance during neurorepair. Endothelial progenitor cells (EPCs) constitute a pool of circulating bone-marrow derived cells that mobilize after an ischemic injury with the potential to incorporate into the damaged endothelium, to form new vessels, or to secrete trophic factors stimulating vessel remodeling. The circulating levels of EPCs are altered after stroke, and several subpopulations have proved to boost brain neurorepair in preclinical models of cerebral ischemia. The goal of this review is to discuss the current state of the neuroreparative actions of EPCs, focusing on their paracrine signaling mechanisms thorough their secretome and released extracellular vesicles.

The application of nanoparticles for neuroprotection in acute ischemic stroke

Stroke still represents one of the most common causes of death and disability worldwide. Acute ischemic stroke (AIS), caused by brain arterial occlusion resulting from a thrombus or embolus, is the most common form of stroke. However, current therapies in AIS are inadequate, and the only US FDA approved treatment is the thrombolytic drug Alteplase. Therefore, establishing effective therapeutic strategies for AIS is urgently needed. Using nanoparticle-based technologies to deliver neuroprotective agents to the ischemic area has attracted increasing attention of late. In this review, the important molecular pathological mechanisms in cerebral ischemia are briefly summarized, the potential of nanoparticulate drug-delivery systems for AIS intervention and recovery are introduced and problems in the medical application of nanoparticles will also be discussed.

Protective effects of phycocyanin on ischemia/reperfusion liver injuries

In this study, phycocyanin (Pc) extracted from Spirulina platensis was used to evaluate its antioxidants effects after ischemia/reperfusion injury (IRI) using the ex-vivo model of isolated perfused rat liver. The rats were divided into eight groups : Control group, where livers were directly perfused after their removal; Cold Ischemia group (CI), livers were treated in the same way as the control group, except that after their collection, they were stored for 12 h and 24 h in the Krebs Henseleit (KH) preservation solution at 4 °C and Treated group (PHY), livers were preserved in the same way as the preceding group except that the KH solution was enriched with phycocyanin at two different concentrations. Pc, a powerful antioxidant, significantly reduced ischemia/reperfusion injury in the liver. In fact, the addition of phycocyanin to the preservation solution significantly decreased the activity of liver transaminases (AST) and (ALT), alkaline phosphatase (ALP), the rate of lipid peroxidation (MDA) and the activity of certain antioxidant enzymes, essentially glutathione-S-transferase (GST) and glutathione peroxidase (GPx). On the other hand, Pc increases the level of thiol groups in hepatic tissues. In conclusion, the results show the Pc-enriched KH conservation solution is effective in preserving the hepatic graft and protecting it against IRI by acting as a potent antioxidant against the products of oxidative stress.

The HMGB1‑IL‑17A axis contributes to hypoxia/reoxygenation injury via regulation of cardiomyocyte apoptosis and autophagy

Both the high‑mobility group box 1 protein (HMGB1) and interleukin (IL)‑17A serve important roles in myocardial ischemia and reperfusion injury. The purpose of the present study was to evaluate whether HMGB1 could induce IL‑17A secretion and lead to cardiomyocyte hypoxia/reoxygenation (H/R) injury. Neonatal rat cardiomyocytes were treated with HMGB1‑neutralizing antibody, IL‑17A‑neutralizing antibody, recombinant HMGB1 (rHMGB1) and recombinant IL‑17A (rIL‑17A), respectively. Cell viabilities, lactate dehydrogenase and creatine kinase levels were measured. Apoptotic cells were assessed by flow cytometry. The expression of HMGB1, IL‑17A, microtubule‑associated proteins 1A/1B light chain 3B (LC3), Beclin‑1, B‑cell lymphoma (Bcl)‑2 and Bcl‑2‑associated X protein were assessed by western blot analysis. The results demonstrated that HMGB1 significantly increased the expression of IL‑17A. HMGB1 or IL‑17A antibody significantly ameliorated H/R‑induced cell injury and improved the cell viability. In contrast, rHMGB1 or rIL‑17A aggravated cell injury and inhibited the cell viability. Furthermore, cardiomyocytes were treated with HMGB1 or IL‑17A antibody significantly increased Bcl‑2 protein expression and had fewer apoptotic cells, whereas rHMGB1 or rIL‑17A‑treated cardiomyocytes markedly decreased Bcl‑2 protein expression and had more apoptotic cells. Moreover, HMGB1 or IL‑17A antibodies significantly inhibited H/R induced autophagy dysfunction (as determined by the inhibition of Beclin‑1 expression, a lower ratio of LC3‑II to LC3‑I), whereas rHMGB1 or rIL‑17A may promote cardiomyocyte autophagy. Together, these results suggested that the HMGB1‑IL‑17A axis contributes to H/R injury via regulation of cardiomyocyte apoptosis and autophagy.

The UCP2-866G/A Polymorphism Could be Considered as a Genetic Marker of Different Functional Prognosis in Ischemic Stroke After Recanalization

Recent studies based on experimental animal models of stroke have suggested that uncoupling protein 2 (UCP2), an inner mitochondrial membrane protein that is thought to regulate energy metabolism and reduce reactive oxygen species generation, provides protection against reperfusion damage. We aimed to investigate whether -866G/A polymorphism in the promoter of the UCP2 gene, which enhances its transcriptional activity, is associated with functional prognosis in patients with embolic ischemic stroke after early recanalization. We investigate a hospital-based prospective cohort of patients with acute ischemic stroke due to occlusion of the middle cerebral artery diagnosed by transcranial Doppler who obtained a partial/complete recanalization 24 h after administration of intravenous thrombolysis. The main end point of the study was functional independence defined as modified Rankin Scale 0-2 on day 90. A total of 80 patients were enrolled. The UCP2-866G/A polymorphism was determined by polymerase chain reaction-restriction fragment length polymorphism technique (14 genotype A/A (18%), 45 genotype A/G (56%) and 21 genotype G/G (26%). The percentage of patients with good functional outcome at 3 months was significantly higher in patients harboring the A/A genotype than in those with A/G or G/G genotypes (85 vs 41%, p = 0.01). The A/A genotype was found to be an independent marker of good prognosis after adjustment for secondary variables (age, sex, glucose level, NIHSS score at baseline, complete recanalization and early neurological improvement) in a logistic regression analysis (OR 0.05, 95% CI 0.01-0.48, p = 0.01). Our results suggest that the AA genotype of UCP2-866 may predict a better functional outcome in ischemic stroke after recanalization of proximal MCA occlusion.

Phenothiazines Enhance Mild Hypothermia-induced Neuroprotection via PI3K/Akt Regulation in Experimental Stroke

Physical hypothermia has long been considered a promising neuroprotective treatment of ischemic stroke, but the treatment's various complications along with the impractical duration and depth of therapy significantly narrow its clinical scope. In the present study, the model of reversible right middle cerebral artery occlusion (MCAO) for 2 h was used. We combined hypothermia (33-35 °C for 1 h) with phenothiazine neuroleptics (chlorpromazine & promethazine) as additive neuroprotectants, with the aim of augmenting its efficacy while only using mild temperatures. We also investigated its therapeutic effects on the Phosphatidylinositol 3 kinase/Protein kinase B (PI3K/Akt) apoptotic pathway. The combination treatment achieved reduction in ischemic rat temperatures in the rectum, cortex and striatum significantly (P < 0.01) faster than hypothermia alone, accompanied by more obvious (P < 0.01) reduction of brain infarct volume and neurological deficits. The combination treatment remarkably (P < 0.05) increased expression of p-Akt and anti-apoptotic proteins (Bcl-2 and Bcl-xL), while reduced expression of pro-apoptotic proteins (AIF and Bax). Finally, the treatment's neuroprotective effects were blocked by a p-Akt inhibitor. By combining hypothermia with phenothiazines, we significantly enhanced the neuroprotective effects of mild hypothermia. This study also sheds light on the possible molecular mechanism for these effects which involves the PI3K/Akt signaling and apoptotic pathway.

Evaluation of potential changes in liver and lung tissue of rats in an ischemia-reperfusion injury model (modified pringle maneuver)

In surgical procedures involving the liver, such as transplantation, resection, and trauma, a temporary occlusion of hepatic vessels may be required. This study was designed to analyze the lesions promoted by ischemia and reperfusion injury of the hepatic pedicle, in the liver and lung, using histopathological and immunohistochemical techniques. In total, 39 Wistar rats were divided into four groups: control group (C n = 3) and ischemia groups subjected to 10, 20, and 30 minutes of hepatic pedicle clamping (I10, n = 12; I20, n = 12; I30, n = 12). Each ischemia group was subdivided into four subgroups of reperfusion (R15, n = 3; R30, n = 3; R60, n = 3; R120, n = 3), after 15, 30, 60, and 120 minutes of reperfusion, respectively. Significant differences were observed in the liver parenchyma (P < 0.05) between the values of microvesicles and hydropic degeneration at different times of ischemia and reperfusion. However, the values of vascular congestion, necrosis, and pyknotic nuclei showed no significant differences (P > 0.05). In the lung parenchyma, a significant difference was observed (P < 0.05) between the values of alveolar septal wall thickening and inflammatory infiltration at different times of ischemia and reperfusion. However, there was no significant difference (P < 0.05) between the values of vascular congestion, bronchial epithelial degeneration, interstitial edema, and hemorrhage. The positive immunoreactivity of caspase-3 protein in the liver parenchyma (indication of ongoing apoptosis), showed no significant differences (P > 0.05) at different times of ischemia and reperfusion. In the pulmonary parenchyma, the immunoreactivity was not specific, and was not quantified. This study demonstrated that the longer the duration of ischemia and reperfusion, the greater are the morphological lesions found in the hepatic and pulmonary parenchyma.

Reactive Oxygen Species Shielding Hydrogel for the Delivery of Adherent and Nonadherent Therapeutic Cell Types<sup/>

Cell therapies suffer from poor survival post-transplant due to placement into hostile implant sites characterized by host immune response and innate production of high levels of reactive oxygen species (ROS). We hypothesized that cellular encapsulation within an injectable, antioxidant hydrogel would improve viability of cells exposed to high oxidative stress. To test this hypothesis, we applied a dual thermo- and ROS-responsive hydrogel comprising the ABC triblock polymer poly[(propylene sulfide)-block-(N,N-dimethyl acrylamide)-block-(N-isopropylacrylamide)] (PPS₁₃₅-b-PDMA₁₅₂-b-PNIPAAM₂₂₅, PDN). The PPS chemistry reacts irreversibly with ROS such as hydrogen peroxide (H₂O₂), imparting inherent antioxidant properties to the system. Here, PDN hydrogels were successfully integrated with type 1 collagen to form ROS-protective, composite hydrogels amenable to spreading and growth of adherent cell types such as mesenchymal stem cells (MSCs). It was also shown that, using a control hydrogel substituting nonreactive polycaprolactone in place of PPS, the ROS-reactive PPS chemistry is directly responsible for PDN hydrogel cytoprotection of both MSCs and insulin-producing β-cell pseudo-islets against H₂O₂ toxicity. In sum, these results establish the potential of cytoprotective, thermogelling PDN biomaterials for injectable delivery of cell therapies.

AKT2 Blocks Nucleus Translocation of Apoptosis-Inducing Factor (AIF) and Endonuclease G (EndoG) While Promoting Caspase Activation during Cardiac Ischemia

The AKT (protein kinase B, PKB) family has been shown to participate in diverse cellular processes, including apoptosis. Previous studies demonstrated that protein kinase B2 (AKT2^−/−) mice heart was sensitized to apoptosis in response to ischemic injury. However, little is known about the mechanism and apoptotic signaling pathway. Here, we show that AKT2 inhibition does not affect the development of cardiomyocytes but increases cell death during cardiomyocyte ischemia. Caspase-dependent apoptosis of both the extrinsic and intrinsic pathway was inactivated in cardiomyocytes with AKT2 inhibition during ischemia, while significant mitochondrial disruption was observed as well as intracytosolic translocation of cytochrome C (Cyto C) together with apoptosis-inducing factor (AIF) and endonuclease G (EndoG), both of which are proven to conduct DNA degradation in a range of cell death stimuli. Therefore, mitochondria-dependent cell death was investigated and the results suggested that AIF and EndoG nucleus translocation causes cardiomyocyte DNA degradation during ischemia when AKT2 is blocked. These data are the first to show a previous unrecognized function and mechanism of AKT2 in regulating cardiomyocyte survival during ischemia by inducing a unique mitochondrial-dependent DNA degradation pathway when it is inhibited.