Effects of sevoflurane preconditioning and postconditioning on rat myocardial stunning in ischemic reperfusion injury

Protective Effect of Sevoflurane Preconditioning on Cardiomyocytes Against Hypoxia/Reoxygenation Injury by Modulating Iron Homeostasis and Ferroptosis

To investigate the mechanism whereby sevoflurane (Sev) protects cardiomyocytes from hypoxia/reoxygenation (H/R) injury. The rat cardiomyocyte line H9C2 was exposed to hypoxia (1% oxygen) for 24 h, followed by reoxygenation for 2 h to construct a model of H/R injury. H9C2 was exposed to 2.4% Sev for 45 min before creating a hypoxic environment to observe the effect of Sev. MTT was taken to assess the viability of each group of cells, flow cytometry to detect cell apoptosis, and qRT-PCR or western blot to detect the expression of iron metabolism-related proteins and apoptosis-related proteins in the cells. And the kit determined the levels of total Fe and Fe²⁺ as well as factors related to oxidative stress in the cells. Administration of Sev significantly increased the cell viability of the H/R group while decreasing the expression of apoptosis-related proteins (Bax, cleaved caspase-3). Ferroportin 1 and mitochondrial ferritin, which are associated with iron metabolism, were considerably up-regulated by Sev, while iron regulatory protein 1, divalent metal transporter 1, and transferrin receptor 1 were significantly down-regulated in H/R cells. Additionally, Sev substantially reduced the levels of total Fe and Fe²⁺, reactive oxygen species, malondialdehyde, and 4-hydroxynonenal in H/R cells. In conclusion, Sev relieves H/R-induced cardiomyocyte injury by regulating iron homeostasis and ferroptosis.

Effects of Sevoflurane on Apoptosis of Myocardial Cells in IRI Rats

Background

Cardiomyocyte apoptosis functions essentially in ischemia/reperfusion- (I/R-) induced myocardial injury. It is suggested that autophagy is widely implicated in the regulation of cell survival and death. Sevoflurane, as a largely used inhalational general anesthetic, has been shown to have a protective effect on cardiomyocytes. However, it was yet elusive on the underlying mechanisms.

Aim

The objective of this study is to investigate the association of sevoflurane-mediated cardioprotective effects with autophagy regulation.

Methods

An in vitro hypoxia model was established in primary cardiomyocytes from fresh myocardial tissue of the rats. The apoptosis rate of myocardial cells treated with hypoxia and treated with sevoflurane was measured. Western blot and immunocytochemical assay were used to measure the protein expression. The cell proliferation rate and cell apoptosis were measured using the MTT assay and flow cytometry, respectively.

Results

The expression of apoptotic proteins including B cell lymphoma-2 (Bcl-2), CCAAT/enhancer-binding protein homologous protein (CHOP), glucose-regulated protein 78 (GRP78), and Bcl-2-associated X protein (BAX) in myocardium treated with sevoflurane was significantly lower than that in myocardium treated with hypoxia. The expression of adhesion proteins such as intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin in myocardium treated with sevoflurane was higher than that in myocardium treated with hypoxia, suggesting better connectivity of the myocardium.

Conclusion

Sevoflurane treatment reduced the apoptosis of myocardial cells after hypoxia treatment.

Sevoflurane inhibits the apoptosis of hypoxia/reoxygenation-induced cardiomyocytes via regulating miR-27a-3p-mediated autophagy

INTRODUCTION

Sevoflurane (Sevo) prevents hypoxia/reoxygenation (H/R)-induced cardiomyocytes apoptosis. MiR-27a-3p expression is up-regulated in Sevo-treated hippocampal neurons.

OBJECTIVE

This study explored whether the effect of Sevo on cardiomyocytes was mediated by miR-27a-3p.

METHODS

The cardiomyocytes were cultured under H/R condition or pre-treated with Sevo, and further transfected with miR-27a-3p inhibitor or treated with an autophagy inhibitor 3-methyladenine (3-MA). Then the cell morphology was observed under an optical microscope. The cell viability and apoptosis were measured by MTT and flow cytometry. Expressions of miR-27a-3p, apoptosis-related, and autophagy-related factors were determined by western blot or RT-qPCR.

KEY FINDINGS

Sevo improved the abnormal morphology, promoted the cell viability and the expressions of Bcl-2 and miR-27a-3p, but reduced the apoptosis and Bax and C-caspase-3 levels of H/R-induced cardiomyocytes. MiR-27a-3p inhibitor had an effect opposite to Sevo on the cardiomyocytes and further counteracted the effect of Sevo on the H/R-induced cardiomyocytes. Downregulation miR-27a-3p increased the expression of Beclin 1 and the ratio of LC3B-II to LC3B-I in H/R-induced cardiomyocytes. Furthermore, 3-MA had an opposite effect to miR-27a-3p inhibitor and further counteracted the effect of the miR-27a-3p inhibitor on H/R-induced cardiomyocytes.

CONCLUSION

Sevo inhibited the apoptosis of H/R-induced cardiomyocytes via regulating miR-27a-3p-mediated autophagy.

Comparison of the effects of sevoflurane and propofol anesthesia on pulmonary function, MMP-9 and postoperative cognition in patients receiving lung cancer resection

Effects of sevoflurane and propofol anesthesia on pulmonary function, matrix metalloproteinase-9 (MMP-9) and postoperative cognition were compared in patients undergoing simple resection of lower lobe of left lung. Retrospective method was used to analyze 58 cases of lung cancer patients treated by simple resection of lower lobe of left lung in the Second Hospital of Dalian Medical University from October 2016 to October 2017, and they were divided into two groups: Sevoflurane group (n=32) with sevoflurane anesthesia and propofol group (n=26) with propofol anesthesia. In the present study, the moment before induction of anesthesia (T1), before the start of one-lung ventilation (T2), before the end of one-lung ventilation (T3), after closed chest surgery (T4), 24 h after surgery (T5), calculate alveolar-arterial oxygen difference (A-aDO2), respiratory index (RI) and intrapulmonary shunt ratio (Qs/Qt), were compared between the two groups. The serum MMP-9 concentration at T1, T4 and T5 were detected by enzyme linked immunosorbent assay. The cognitive function of two groups was assessed by Mini-Mental State Examination (MMSE) 1 day before surgery and 1 and 10 days after surgery. The A-aDO2 level at T4 in sevoflurane group was significantly higher than that in propofol group (P<0.05). The RI level at T3, T4, the Qs/Qt and the MMP-9 level at T4 in the sevoflurane group was significantly higher than that in the propofol group (P<0.05). The MMSE score in sevoflurane group was significantly lower than that in propofol group 1 and 10 days after surgery (P<0.05). Propofol has little effect on pulmonary function and can decrease inflammatory factor MMP-9. Both sevoflurane and propofol have an effect on cognitive function after lung cancer resection, but propofol can reduce cognitive impairment in patients with lung cancer.

Stable perfluorocarbon emulsions for the delivery of halogenated ether anesthetics

BACKGROUND

Research into injectable volatile anesthetics has been ongoing for approximately 40 years, with limited success, in an attempt to address the deficiencies of inhalational anesthesia. The purpose of this work was to formulate and optimize volatile anesthetic carrier emulsions based on our prior work in perfluorocarbon emulsions.

METHODS

Perfluorocarbons were screened for their volatilty and emulsion stability. Optimal anesthetic emulsions were manufactured by high pressure homogenization of a select, clinically relevant perfluorocarbon, isoflurane and a surfactant-containing aqueous phase. Longitudinal particle size, polydispersity and isoflurane content analysis was performed. Observational studies of in vivo efficacy and safety were performed in 225-300 g Lewis Rats (n = 34) with blood chemistry and post study tissue pathology analysis.

RESULTS

Emulsion particle size and isolflurane content in select emulsions were stable at room temperature greater than 300 days. This stability was depedent on perfluorocarbon molecular weight and boiling point. in vivo, emulsions demonstrated a rapid onset and offset. Variability in onset metrics (loss of righting reflex, pain reflexes and time to recovery) was less than 40% amongst individual emulsion preparations (n = 9) utilized in induction trials. No adverse effects due to the intravenous administration of emulsions were observed in blood chemistry results or post-study pathological examination.

CONCLUSIONS

These formulations showed stability, safety and efficacy. In addition to induction and general anesthesia, these emulsions could have utility in global health or in military applications where equipment and resources are limited.

Safety Evaluation of Sevoflurane as Anesthetic Agent in Mouse Model of Myocardial Ischemic Infarction

The selection of anesthetics for patients with myocardial infarction is critically challenging. Sevoflurane is a volatile anesthetic gradually used in recent years. The intraoperative hemodynamic stability of sevoflurane was supported by several studies with some suggestions for its use for patients with cardiac events. The present study was undertaken to investigate the effect of sevoflurane on mice with myocardial infarction to evaluate the safety issue of this agent for possible application in patients with myocardial infarction. Mice of 7-12 weeks old were subjected to left anterior descending artery ligation to introduce acute myocardial infarction. The effect of sevoflurane on the hemodynamics was examined in comparison with that of currently available agent etomidate at low and moderate doses. The results showed that sevoflurane caused unstable hemodynamic changes in mice with myocardial infarction at both low and moderate inhaled concentrations relative to low and moderate doses of etomidate. In addition, the relative safety margin estimated from therapeutic index was decreased by 50 % when sevoflurane was used for mice with myocardial infarction relative to control mice, but only decreased by 20 % for etomidate. These analyses indicate that in comparison with currently available agent etomidate, sevoflurane should not be applied to patients with myocardial infarction or other cardiac events.

Wnt/Glycogen Synthase Kinase 3β/β-catenin Signaling Activation Mediated Sevoflurane Preconditioning-induced Cardioprotection

Background:

Sevoflurane preconditioning (SP) has been shown to invoke potent myocardial protection in animal studies and clinical trials. However, the mechanisms underlying SP are complex and not yet well understood. We investigated the hypothesis that the cardioprotection afforded by SP is mediated via the Wnt/glycogen synthase kinase 3β (GSK3β)/β-catenin signaling pathway.

Methods:

Two models were established: A Langendorff perfused rat heart model and the H9C2 cell hypoxia/reoxygenation model. Both rats and H9C2 cells were randomly divided into 6 groups as follows: S group, ischemia-reperfusion (I/R) group, DMSO group, IWP group, SP group, and SP + IWP group. Hemodynamic parameters, lactate dehydrogenase (LDH) activity in coronary effluent and cell culture supernatant, and the infarct size were measured to evaluate myocardial ischemia-reperfusion injuries. To determine the activity of Wnt/GSK3β/β-catenin signaling pathway, the expressions of Wnt3a, phospho-GSK3β, and β-catenin were measured by Western blotting.

Results:

SP improved cardiac function recovery, reduced infarct size (18 ± 2% in the SP group compared with 35 ± 4% in the I/R group; P < 0.05), decreased LDH activity in coronary effluent, and culture supernatant. IWP-2, an inhibitor of Wnt, abolished the cardioprotection by SP. In addition, Western blotting analysis demonstrated that the expressions of Wnt3a, phospho-GSK3β, and β-catenin significantly (P < 0.05) increased in the I/R group, compared with the S group; and compared to I/R group, SP significantly (P < 0.05) increased Wnt3a, phospho-GSK3β, and β-catenin expressions. Pretreatment with IWP-2 significantly (P < 0.05) abolished SP-induced Wnt/GSK3β/β-catenin signaling activation.

Conclusions:

The results showed for the first time that cardioprotection afforded by SP may be mediated partly via the Wnt/GSK3β/β-catenin signaling pathway.

The mechanisms of cardio-protective effects of desflurane and sevoflurane at the time of reperfusion: anaesthetic post-conditioning potentially translatable to humans?

Myocardial conditioning is actually an essential strategy in the management of ischaemia-reperfusion injury. The concept of anaesthetic post-conditioning is intriguing, its action occurring at a pivotal moment (that of reperfusion when ischaemia reperfusion lesions are initiated) where the activation of these cardio-protective mechanisms could overpower the mechanisms leading to ischaemia reperfusion injuries. Desflurane and sevoflurane are volatile anaesthetics frequently used during cardiac surgery. This review focuses on the efficacy of desflurane and sevoflurane administered during early reperfusion as a potential cardio-protective strategy. In the context of experimental studies in animal models and in human atrial tissues in vitro, the mechanisms underlying the cardio-protective effect of these agents and their capacity to induce post-conditioning have been reviewed in detail, underlining the role of reactive oxygen species generation, the activation of the cellular signalling pathways, and the actions on mitochondria along with the translatable actions in humans; this might well be sufficient to set the basis for launching randomized clinical studies, actually needed to confirm this strategy as one of real impact.

Meta-analysis of the cardioprotective effect of sevoflurane versus propofol during cardiac surgery

BACKGROUND

To evaluate the cardioprotective effects of sevoflurane versus propofol anesthesia in patients undergoing cardiac surgery.

METHODS

Studies were retrieved through searching several databases. Study quality was evaluated by Jadad scale. Meta-analysis was performed with RevMan5.0 software. Publication bias was tested by funnel plot.

RESULTS

As a result, 15 studies were included. Compared with propofol, sevoflurane anesthesia significantly improved postoperative (WMD (weighted mean difference) = 0.62, 95% CI: 0.33 to 0.92; P < 0.0001) and postoperative 12 hour cardiac index (WMD = 0.18, 95% CI: 0.03 to 0.33; P = 0.02), postoperative cardiac output (WMD = 1.14, 95% CI: 0.74 to 1.54; P < 0.00001), and reduced postoperative 24 hour cardiac troponin I concentration (WMD = -0.86, 95% CI:-1.49 to -0.22; P = 0.008), postoperative inotropic drug usage (OR (odds ratio) = 0.31, 95% CI: 0.22 to 0.44; P < 0.00001), vasoconstrictor drug usage (OR = 0.30, 95% CI:0.21 to 0.43; P < 0.00001), ICU stay (WMD = -15.53, 95% CI: -24.29 to -6.58; P = 0.0007) and a trial fibrillation incidence (OR = 0.25, 95% CI: 0.07 to 0.85; P = 0.03). However, no significant differences were found in other indexes. Subgroup analysis indicated the similar results.

DISCUSSION

The sevoflurane-induced cTnI reduction is associated with lower incidence of late adverse cardiac events, accounting for its roles in cardiac protection. Several limitations existed such as the small sample size and the lack use of blind design.

CONCLUSIONS

Sevoflurane may exhibit a more favorable cardioprotective effect during cardiac surgery than propofol.

Late Post-Conditioning with Sevoflurane after Cardiac Surgery--Are Surrogate Markers Associated with Clinical Outcome?

Introduction

In a recent randomized controlled trial our group has demonstrated in 102 patients that late post-conditioning with sevoflurane performed in the intensive care unit after surgery involving extracorporeal circulation reduced damage to cardiomyocytes exposed to ischemia reperfusion injury. On the first post-operative day the sevoflurane patients presented with lower troponin T values when compared with those undergoing propofol sedation. In order to assess possible clinical relevant long-term implications in patients enrolled in this study, we performed the current retrospective analysis focusing on cardiac and non-cardiac events during the first 6 months after surgery.

Methods

All patients who had successfully completed the late post-conditioning trial were included into this follow-up. Our primary and secondary endpoints were the proportion of patients experiencing cardiac and non-cardiac events, respectively. Additionally, we were interested in assessing therapeutic interventions such as initiation or change of drug therapy, interventional treatment or surgery.

Results

Of 102 patients analyzed in the primary study 94 could be included in this follow-up. In the sevoflurane group (with 41 patients) 16 (39%) experienced one or several cardiac events within 6 months after cardiac surgery, in the propofol group (with 53 patients) 19 (36%, p=0.75). Four patients (9%) with sevoflurane vs. 7 (13%) with propofol sedation had non-cardiac events (p=0.61). While a similar percentage of patients suffered from cardiac and/or non-cardiac events, only 12 patients in the sevoflurane group compared to 20 propofol patients needed a therapeutic intervention (OR: 0.24, 95% CI: 0.04-1.43, p=0.12). A similar result was found for hospital admissions: 2 patients in the sevoflurane group had to be re-admitted to the hospital compared to 8 in the propofol group (OR 0.23, 95% CI: 0.04-1.29, p=0.10).

Conclusions

Sevoflurane does not seem to provide protection with regard to the occurrence of cardiac and non-cardiac events in the 6-month period following cardiac surgery with the use of extracorporeal circulation. However, there was a clear trend towards fewer interventions (less need for treatment, fewer hospital admissions) associated with sevoflurane post-conditioning in patients experiencing any event. Such results might encourage launching large multicenter post-conditioning trials with clinical outcome defined as primary endpoint.

Pharmacological postconditioning with diazoxide attenuates ischemia/reperfusion-induced injury in rat liver

It has been demonstrated that ischemic postconditioning (IPO) is capable of attenuating ischemia/reperfusion (I/R) injury in the heart. However, the novel role of pharmacological postconditioning in the liver remains unclear. In this study, the hypothesis that diazoxide postconditioning reduces I/R-induced injury in rat liver was tested. Rats were assigned randomly to the sham-operated control, I/R (occlusion of the porta hepatis for 60 min, followed by a persistent reperfusion for 120 min), diazoxide ischemic postconditioning (DIPO; occlusion of the porta hepatis for 60 min, then treatment with diazoxide for 10 min reperfusion, followed by a persistent reperfusion for 110 min) or 5-hydroxydecanoate (5-HD)+DIPO (occlusion of the porta hepatis for 60 min, then treatment with diazoxide and 5-HD for 10 min reperfusion, followed by a persistent reperfusion for 110 min) groups. The alanine aminotransferase (ALT) and aspartate transaminase (AST) levels were assayed. The expression levels of protein kinase c-ε (pkc-ε), cytochrome c (cyt-c), caspase-3 and bcl-2 protein were determined by western blotting. The serum levels of ALT and AST and expression levels of cyt-c and caspase-3 were significantly lower in the DIPO group (P<0.05). However, the protein expression levels of pkc-ε and bcl-2 were markedly increased in the DIPO group (P<0.05). 5-HD abrogated the protective effects of DIPO. The data of the present study provide the first evidence that DIPO protects the liver from I/R injury by opening the mitochondrial K_ATP channels, activating and upregulating pkc-ε and inhibiting the activation of the apoptotic pathway by decreasing the release of cyt-c and the expression of caspase-3 and increasing bcl-2 expression.

Myocardial postconditioning: next step to cardioprotection

Myocardial ischemia is a condition in which lack of blood flow to the cardiac muscle occurs resulting in deficient oxygen and nutrient supply to the heart. The restoration of blood flow to an organ or tissue is termed reperfusion. Brief episodes of ischemia and reperfusion given after prolonged ischemia and at the onset of reperfusion denotes postconditioning. Myocardial postconditioning is a phenomenon in which myocardium from lethal ischemia-reperfusion injury is protected. However, numerous experimental studies reveal that the cardioprotective effects of postconditioning are suppressed in various pathological states. This review critically discusses the mechanisms involved in the cardioprotective effects of postconditioning and factors affecting the cardioprotective potential of myocardial postconditioning.