Reduce Ischemia-reperfusion Injury Research Articles

Prostaglandin E1 administration post liver transplantation and renal outcomes: A retrospective single center experience.

Prostaglandin E1 (PGE1), or alprostadil, is a potent vasodilator that improves hepatic blood flow and reduces ischemia-reperfusion injury post-liver transplantation (LT). However, the benefits of PGE1 on renal function after LT have not yet been well described. To assess the impact of PGE1 administration on renal function in patients who underwent liver or liver-kidney transplant. This retrospective study included all patients who underwent liver or liver-kidney transplant at our institution from January, 2011 to December, 2021. Patients were classified based on whether they received PGE1. PGE1 was administered post-LT to those with transaminases > 1000 U/L in the immediate postoperative period. Demographics, post-LT treatments and/or complications, renal function, and survival were analyzed. Multivariable logistic regression analysis was performed, and a two-tailed P value < 0.05 was considered statistically significant. A total of 145 patients underwent LT, with 44 (30%) receiving PGE1. Baseline patient characteristics were comparable, except the PGE1 group had significantly higher aspartate aminotransferase (AST) (1961.9 U/L ± 1862.3 U/L vs 878 U/L ± 741.4 U/L, P = 0.000), alanine aminotransferase (1070.6 U/L ± 895 U/L vs 547.7 U/L ± 410 U/L, P = 0.000), international normalized ratio on post-LT day 1 (2 ± 0.74 vs 1.8 ± 0.4, P = 0.03), a longer intensive care unit stay (8.1 days ± 11.8 days vs 3.8 days ± 4.6 days, P = 0.003), more vasopressor use (55.53 hours ± 111 hours vs 16.33 hours ± 26.3 hours, P = 0.002), and higher immediate postoperative complications (18.6% vs 4.9%, P = 0.04). The PGE1 group also had a significantly higher 90-day readmission rate (29.6% vs 13.1%, P = 0.02) and lower 1-year liver graft survival (87.5% vs 98.9%, P = 0.005). However, 30-day readmission (31.6% vs 27.4%, P = 0.64), LT complications (hepatic artery thrombosis, biliary complications, rejection of liver graft, cardiomyopathy), 1-year patient survival (96.9% vs 97.8%, P = 0.77), overall liver graft survival, and overall patient survival were similar between the two groups (95.4% vs 93.9%, P = 0.74 and 88.4% vs 86.9%, P = 0.81 respectively). Although the PGE1 group had a significantly lower glomerular filtration rate (eGFR) on post-LT day 7 (46.3 mL/minute ± 26.7 mL/minute vs 62.5 mL/minute ± 34 mL/minute, P = 0.009), the eventual need for renal replacement therapy (13.6% vs 5.9%, P = 0.09), the number of dialysis sessions (0.91 vs 0.27, P = 0.13), and eGFR at 1-month (37.2 mL/minute ± 35.9 mL/minute vs 42 mL/minute ± 36.9 mL/minute, P = 0.49), 6-months (54.8 mL/minute ± 21.6 mL/minute vs 62 mL/minute ± 21.4 mL/minute, P = 0.09), and 12-months (63.7 mL/minute ± 20.7 mL/minute vs 62.8 mL/minute ± 20.3 mL/minute, P = 0.85) post-LT were similar to those in the non-PGE1 group. In patients who received PGE1 for ischemia-reperfusion injury, despite immediate acute renal injury post-LT, the renal function at 1-month, 6-months, and 12-months post-LT was similar compared to those without ischemia-reperfusion injury. Prospective clinical trials are needed to further elucidate the benefits of PGE1 use in renal function.

Abstract 4146302: NETosis Attenuating Nanoprobe Improves Survival after Cardiac Arrest

NETosis, the process of neutrophil cell death due to the formation and release of neutrophil extracellular traps (NETs) has been implicated in the pathogenesis of heart disease. NETs are composed of immunogenic DNA fragments and citrullinated histones. The role of NETosis in the context of cardiac arrest and resuscitation (CA/R) is however unknown. We previously reported the development of a Dextran-Thiazole Orange (DTO) nanoprobe, with nanomolar affinity for nucleic acids, that exerts acute anti-inflammatory effects and reduces ischemia-reperfusion injury in mice. We aimed here to determine whether the DTO nanoprobe would also bind to the nucleic acid in NETS, whether DTO could attenuate the intensity of NETosis, and whether this would improve outcomes and survival after cardiac arrest. C57Bl6 mice were arrested for 8 minutes before resuscitation. DTO or unmodified dextran (vehicle control) was injected at the time of resuscitation, and again 4 hours later (n=38 mice). Survival and neurological function were scored daily. Time-domain resolved (lifetime) and conventional fluorescence imaging was performed at 4 hours after resuscitation in 6 additional mice injected with DTO. NETosis was evaluated by protein blot in the hearts of cardiac arrest mice injected with DTO or control. DTO significantly (p&lt;0.05) improved 10-day survival (Fig. A), mean survival (from 4 to 7 days, Fig. B), and neurological function (Fig. C) following CA/R. Lifetime imaging (Fig. D), but not conventional fluorescence imaging (Fig. E) revealed the presence of DTO in the injured heart, liver and kidneys. In the heart, DTO signal was significantly increased in CA/R compared to sham mice injected with DTO or CA/R mice injected with control dextran (Fig. F). Citrullinated H3 and HMGB-1 (High mobility group box 1, a chromatin protein) were both upregulated in CA/R, and were significantly attenuated by DTO injection (Fig. G-I). We show for the first time that NETosis plays a key role in cardiac arrest and resuscitation. DTO is capable of detecting NETosis as well as attenuating it, likely via a reduction in HMGB-1 activity. The modulation of NETosis may provide a new avenue to improve survival after cardiac arrest.

Novel Calcitonin Gene-Related Peptide (CGRP) Interfering Migraine Therapies and Stroke-A Review.

Migraine and stroke are neurological disorders with significant global prevalence and impact. Recent advances in migraine therapy have focused on the calcitonin gene-related peptide (CGRP) pathway. This review examines the shared pathomechanisms between migraine and stroke, with emphasis on the role of CGRP. We analyze the current literature on CGRP's functions in cerebrovascular regulation, edema formation, neuroinflammation, and neuroprotection. CGRP acts as a potent vasodilator and plays a crucial role in trigeminovascular activation during migraine attacks. In stroke, CGRP has demonstrated neuroprotective effects by improving collateral circulation and reducing ischemia-reperfusion injury. Concerns have been raised about the potential impact of CGRP inhibitors on stroke risk and outcomes. Studies in animals suggest that CGRP receptor antagonists may worsen cerebral ischemia by impairing collateral flow. We discuss the implications of these findings for the use of CGRP-targeting therapies in migraine patients, especially those at increased risk of stroke. Additionally, we explore the complex interplay between CGRP, endothelial function, and platelet activity in both conditions. This review highlights the need for further research to elucidate the long-term cerebrovascular safety of CGRP pathway inhibitors and to identify potential subgroups of migraine patients who may be at higher risk of adverse cerebrovascular events with these novel therapies.

Using an Isolated Working Rat Heart Model to Test Donor Heart Preservation Strategies.

Optimization of donor heart preservation solutions has played a key role in reducing ischemia-reperfusion injury in donor hearts during organ retrieval, transportation, and transplantation. Previous work from our laboratory showed that the addition of glyceryl trinitrate and erythropoietin to donor heart preservation solutions could significantly improve cardiac functional recovery after prolonged cold storage and in donation after circulatory death hearts. This supplementation protocol has been implemented in clinical use in transplant units around Australia, Belgium, and the United Kingdom. Here, we outline a protocol for testing supplementation strategies using an ex vivo isolated working rat heart (IWRH) perfusion circuit. Using this methodology, supplementation strategies can be tested in the context of prolonged cold static storage, donation after brain death, and donation after circulatory death donor heart preservation. Cardiac functional recovery, measured by aortic flow, coronary flow, cardiac output, pulse pressure, and heart rate, can be used to determine whether a particular preservation strategy can minimize ischemia-reperfusion injury of the donor heart.

Innovative Strategies for Liver Transplantation: The Role of Mesenchymal Stem Cells and Their Cell-Free Derivatives.

Despite being the standard treatment for end-stage liver disease, liver transplantation has limitations like donor scarcity, high surgical costs, and immune rejection risks. Mesenchymal stem cells (MSCs) and their derivatives offer potential for liver regeneration and transplantation. MSCs, known for their multipotency, low immunogenicity, and ease of obtainability, can differentiate into hepatocyte-like cells and secrete bioactive factors that promote liver repair and reduce immune rejection. However, the clinical application of MSCs is limited by risks such as aberrant differentiation and low engraftment rates. As a safer alternative, MSC-derived secretomes and extracellular vesicles (EVs) offer promising therapeutic benefits, including enhanced graft survival, immunomodulation, and reduced ischemia-reperfusion injury. Current research highlights the efficacy of MSC-derived therapies in improving liver transplant outcomes, but further studies are necessary to standardize clinical applications. This review highlights the potential of MSCs and EVs to address key challenges in liver transplantation, paving the way for innovative therapeutic strategies.

Gradual Reperfusion in Cardioplegia-Induced Cardiac Arrest.

Background and Objectives: The majority of cardiac surgical procedures are performed using cardiopulmonary bypass and cardioplegia-induced cardiac arrest. Cardiac arrest and reperfusion may lead to ischemia-reperfusion injury of the myocardium. The aim of this study was to investigate whether gradual reperfusion with a slow increase in oxygen partial pressure leads to a reduction in reperfusion injury. Materials and Methods: Fifty patients undergoing elective cardiac surgery were included in this prospective randomized study. Patients in the hyperoxemic (control) group received conventional reoxygenation (paO2 250-300 mmHg). Patients in the normoxemic (study) group received gradual reoxygenation (1st-minute venous blood with paO2 30-40 mmHg, 2nd-minute arterial blood with paO2 100-150 mmHg). Periprocedural blood samples were taken serially, and markers of myocardial injury were analyzed. In addition, the influence of gradual reoxygenation on hemodynamics, inflammation, and the overall perioperative course was evaluated. Results: There was a trend toward higher CK levels in the hyperoxemia group without statistical significance; however, CK-MB and troponin T levels did not show any statistical difference between the two groups. Potassium concentrations in the coronary sinus were significantly higher in the hyperoxemia group at 3 and 8 min after opening of the aortic cross-clamp (6.88 ± 0.87 mmol/L vs. 6.30 ± 0.91 mmol/L and 5.87 ± 0.73 mmol/L vs. 5.43 ± 0.42 mmol/L, respectively; p = 0.03 and p = 0.02). All other measurements did not show a statistical difference between the two groups. Conclusions: The use of gradual reperfusion in cardiac surgery with cardiopulmonary bypass and cardiac arrest is safe. However, it does not reduce ischemia-reperfusion injury compared to standard hyperoxemic reperfusion.

Perfusate hemoglobin during normothermic liver machine perfusion as biomarker of early allograft dysfunction: Apilot study.

Normothermic machine perfusion (NMP) aims to reduce ischemia-reperfusion injury in donor livers and its clinical manifestation, early allograft dysfunction (EAD) by maintaining perfusion and oxygenation. However, there is limited data on which NMP perfusate biomarkers might be associated with such EAD and the role of perfusate hemoglobin has not been assessed. We performed a pilot retrospective analysis of adult donor livers undergoing NMP between 2020 and 2022 at our center. NMP was commenced at the recipient hospital after initial static cold storage. All NMP circuits were primed in the same manner according to the manufacturer's instructions. Livers were stratified by initial perfusate hemoglobin below (≤5.2 mmol/L) or above (>5.2 mmol/L) the median. The association between hemoglobin levels and EAD or recipient peak transaminase levels was assessed. Among 23 livers, eight were considered unsuitable for transplantation, leaving 15 livers for assessment. Higher initial hemoglobin was associated with a lower risk of EAD (0% vs. 55.6%, p = 0.04). Perfusate hemoglobin decreased after NMP initiation (p = 0.003) and negatively correlated with recipient peak transaminase levels (ALT: ρ = -0.72, p = 0.002; AST: ρ = -0.79, p < 0.001). Consistently, higher hemoglobin livers also demonstrated lower perfusate liver enzymes. Perfusate hemoglobin levels decreased during NMP, and lower perfusate hemoglobin levels were associated with a higher incidence of EAD and higher levels of liver injury markers. Maintaining higher hemoglobin levels during NMP may help reduce ischemia-reperfusion injury and prevent or attenuate EAD. Larger prospective studies are needed to validate the findings of this pilot study.

Innovations in Liver Preservation Techniques for Transplants from Donors after Circulatory Death: A Special Focus on Transplant Oncology.

Liver transplantation is the preferred treatment for end-stage liver disease. Emerging evidence suggests a potential role for liver transplantation in treating liver tumors such as colorectal liver metastases and cholangiocarcinoma. However, due to a limited donor pool, the use of marginal grafts from donation after circulatory death (DCD) donors is increasing to meet demand. Machine perfusion is crucial in this context for improving graft acceptance rates and reducing ischemia-reperfusion injury. Few studies have evaluated the role of machine perfusion in the context of transplant oncology. Perfusion machines can be utilized in situ (normothermic regional perfusion-NRP) or ex situ (hypothermic and normothermic machine perfusion), either in combination or as a complement to conventional in situ cold flush and static cold storage. The objective of this analysis is to provide an up-to-date overview of perfusion machines and their function in donation after circulatory death with particular attention to their current and likely potential effects on transplant oncology. A literature review comparing standard cold storage to machine perfusion methods showed that, so far, there is no evidence that these devices can reduce the tumor recurrence rate. However, some evidence suggests that these innovative perfusion techniques can improve graft function, reduce ischemia-reperfusion injury, and, based on this mechanism, may lead to future improvements in cancer recurrence.

Therapeutic interventions using the peritoneal and coelomic cavity in dogs, cats, and exotic pets.

To provide a video tutorial describing intraperitoneal (IP) and intracoelomic (IC) therapeutics (IP/IC fluid therapy, euthanasia, direct peritoneal resuscitation). Dogs, cats, and exotic pets. Peritoneal and coelomic centesis allows for delivery of fluids or to perform euthanasia. The peritoneal and coelomic membranes contain a vast network of capillaries and lymphatics that allow absorption of fluids and blood products. Needles are inserted aseptically IP or IC at species-specific locations to avoid iatrogenic damage. In mammals, the needle is inserted in a periumbilical location at a 1- to 2-cm radius from the umbilicus, while the needle is inserted into the ventral inguinal fossa in chelonians and lateroventrally in lizards and snakes. Direct peritoneal resuscitation is a human technique in which a dextrose/electrolyte solution infused IP reduces ischemia-reperfusion injury, edema, and tissue necrosis to improve mortality in patients with diseases like shock and sepsis or who require acute abdominal surgery. Isotonic crystalloids are given IP/IC at 10- to 20-mL/kg doses (smaller volumes in reptiles) and blood products at standard calculated doses. Sodium pentobarbital without phenytoin (3 mL/4.5 kg) is used for IP/IC euthanasia. Being aware of multiple routes for fluid and blood product administration allows treatment in animals for which intravenous or intraosseous catheterization is undesirable or impossible. While intravenous or intraosseous routes are always preferred, especially for resuscitation, familiarity with locations for IP/IC fluid and euthanasia is useful. Techniques like direct peritoneal resuscitation are not currently used in animals but might be translated to veterinary cases in the future.

Influence of Anesthetic Regimes on Extracellular Vesicles following Remote Ischemic Preconditioning in Coronary Artery Disease.

Remote ischemic preconditioning (RIPC) reduces ischemia-reperfusion injury in aortocoronary bypass surgery, potentially via extracellular vesicles (EVs) and their micro-RNA content. Clinical data implicate that propofol might inhibit the cardioprotective RIPC effect. This prospective, randomized study investigated the influence of different anesthetic regimes on RIPC efficacy and EV micro-RNA signatures. We also assessed the impact of propofol on cell protection after hypoxic conditioning and EV-mediated RIPC in vitro. H9c2 rat cardiomyoblasts were subjected to hypoxia, with or without propofol, and subsequent simulated ischemia-reperfusion injury. Apoptosis was measured by flow cytometry. Blood samples of 64 patients receiving anesthetic maintenance with propofol or isoflurane, along with RIPC or sham procedures, were analyzed, and EVs were enriched using a polymer-based method. Propofol administration corresponded with increased Troponin T levels (4669 ± 435.6 pg/mL), suggesting an inhibition of the cardioprotective RIPC effect. RIPC leads to a notable rise in miR-21 concentrations in the group receiving propofol anesthesia (fold change 7.22 ± 6.6). In vitro experiments showed that apoptosis reduction was compromised with propofol and only occurred in an EV-enriched preconditioning medium, not in an EV-depleted medium. Our study could clinically and experimentally confirm propofol inhibition of RIPC protection. Increased miR-21 expression could provide evidence for a possible inhibitory mechanism.

Quantification of treprostinil concentration in rat and human using a novel validated and rapid liquid chromatography-tandem mass spectrometry method: Experimental and clinical applications in ischemia–reperfusion injury

Treprostinil (Remodulin®) is a Food and Drug Administration (FDA) approved prostacyclin analog to treat pulmonary arterial hypertension. Recently, treprostinil has been investigated to reduce ischemia–reperfusion injury (IRI) during transplantation, which currently has no approved treatment. A validated analytical method is necessary to measure treprostinil concentrations in biological specimens. Here, a novel, sensitive, and specific method to measure treprostinil concentrations in rat serum, human serum, and human plasma has been developed using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Biological samples were processed by protein precipitation before chromatography and 6-keto Prostaglandin F1α-d4 was used as an internal standard. A gradient method was established with a total run time of 4 min. The assay was linear over the range of 0.25–75.0 ng/ml with accuracy (92.97–107.87 %), intra-assay precision (1.16–3.34 %), and inter-assay precision (1.11–4.58 %) in all biological matrices, which are within FDA acceptance criteria. No significant variation in treprostinil or 6-keto Prostaglandin F1α-d4 concentrations were observed under the investigated storage conditions. This novel, sensitive, and specific LC/MS-MS method is cost-effective and suitable for measuring treprostinil concentrations in animal studies and human biological samples for clinical applications.

Electroacupuncture for slow flow/no-reflow phenomenon in patients with acute myocardial infarction undergoing percutaneous coronary intervention: protocol for a pilot randomized controlled trial.

Slow flow/no-reflow (SF-NR) during percutaneous coronary intervention (PCI) is associated with poor prognosis of patients with acute myocardial infarction (AMI). Currently, effective treatment is not available for SF-NR. Electroacupuncture (EA) has shown significant efficacy as an adjuvant therapy for many cardiovascular diseases by improving microcirculation and reducing ischemia-reperfusion injury. However, its effects on SF-NR in the AMI patients during PCI are not clear. This pilot trial aims to determine the efficacy of intraoperative EA in alleviating SF-NR in AMI patients undergoing PCI. This prospective, single-center, randomized controlled, pilot trial will recruit 60 AMI patients scheduled for PCI at the Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, China. The patients will be randomized in a 1:1 ratio into the EA or the control groups. Patients in the control group will undergo standard PCI. Patients in the EA group will undergo intraoperative electroacupuncture while undergoing standard PCI. Incidence of SF-NR is the primary outcome for this study. This study will also assess secondary outcomes including cardiac biomarkers, inflammatory biomarkers, pain and anxiety scores, electrocardiography parameters, traditional Chinese medicine (TCM) symptom score, and major adverse cardiovascular and cerebrovascular events (MACCE). All the included patients will undergo laboratory tests including routine blood tests, levels of electrolytes, as well as liver and renal function tests. Patients will be followed up for 1 month after the procedure. This pilot trial will provide evidence for the potential benefits of intraoperative EA in improving microvascular perfusion and preventing or alleviating SF-NR during PCI in patients with AMI. If proven effective, intraoperative EA will provide a new and effective strategy against SF-NR and provide evidence for subsequent multicenter trials. ClinicalTrials.gov, identifier (ChiCTR2300072265). Registered on 8 June 2023.

UW Supplementation with AP39 Improves Liver Viability Following Static Cold Storage.

Static cold storage of donor livers at 4°C incompletely arrests metabolism, ultimately leading to decreases in ATP levels, oxidative stress, cell death, and organ failure. Hydrogen Sulfide (H2S) is an endogenously produced gas, previously demonstrated to reduce oxidative stress, reduce ATP depletion, and protect from ischemia and reperfusion injury. H2S is difficult to administer due to its rapid release curve, resulting in cellular death at high concentrations. AP39, a mitochondrially targeted, slow-release H2S donor, has been shown to reduce ischemia-reperfusion injury in hearts and kidneys. Thus, we investigated whether the addition of AP39 during 3-day static cold storage can improve liver graft viability. At the end of storage, livers underwent six hours of acellular normothermic machine perfusion, a model of transplantation. During simulated transplantation, livers stored with AP39 showed reduced resistance, reduced cellular damage (ALT and AST), and reduced apoptosis. Additionally, bile production and glucose, as well as energy charge were improved by the addition of AP39. These results indicate that AP39 supplementation improves liver viability during static cold storage.

Nontopical Nitrates in Flap Perfusion and Delay Phenomenon.

Topical nitrates have demonstrated efficacy in improving flap perfusion. However, evidence for nontopical nitrates in modulation of flap perfusion dynamics has yet to be consolidated. Here, we review evidence regarding the use of intravascular, sublingual, and oral nitrates in modulating flap perfusion. We performed a review of the literature for evidence linking nontopical nitrates and flap perfusion, and included clinical studies, animal studies, and in vitro studies. Evidence suggests that intravascular, sublingual, and oral nitrates exert vasodilatory properties, which may be harnessed for identification of perforators and improved flap perfusion. We also found evidence suggesting nitrates may facilitate ischemic preconditioning while reducing ischemia-reperfusion injury. Nitrates delivered intravascularly, sublingually, or orally may increase flap perfusion and serve as a method for ischemic preconditioning, particularly in the intraoperative setting.

Dexmedetomidine preconditioning reduces ischaemia-reperfusion injury in equine model of large colon volvulus.

Large colon volvulus is a cause of colic in horses with high morbidity and mortality when not promptly treated. More treatment options are needed to improve the outcome of these cases by protecting against the damage caused by ischaemia and reperfusion injury. To determine the effect of preconditioning with dexmedetomidine prior to induction of ischaemia-reperfusion (IR) injury in a large colon volvulus model in the horse. Randomised blinded in vivo experiments. Horses received either a dexmedetomidine (DEX) or saline (CON) constant rate infusion (CRI) immediately following induction of anaesthesia. Venous, arterial, and transmural occlusion of a section of the large colon was performed for 3 h, after which the ligatures and clamps were removed to allow for reperfusion for 3 h. Biopsies of the large colon were taken at baseline, 1 and 3 h of ischaemia, and at 1 and 3 h of reperfusion. The severity of crypt epithelial loss (DEX = 2.1 [0.8-2.8], CON = 3.1 [2.5-4], p = 0.03) and mucosal haemorrhage was decreased (DEX = 2.1 [1.3-3], CON = 3.5 [2.5-4], p = 0.03) in group DEX compared to group CON when graded on a scale of 0-4. Crypt length remained longer (DEX = 369.5 ± 91.7 μm, CON = 238.5 ± 72.6 μm, p = 0.02) and interstitium to crypt (I:C) ratio remained lower (DEX = 1.4 (1-1.7), CON = 2.6 [1.8-5.9], p = 0.03) in group DEX compared to group CON during reperfusion. Clinical applicability of pharmacologic preconditioning is limited. Preconditioning with a dexmedetomidine CRI prior to IR injury demonstrated a protective effect histologically on the large colon in the horse. Further investigation into postconditioning with dexmedetomidine is warranted as a possible intervention in colic cases suspected of being large colon volvulus.

Remote ischemic preconditioning versus sham-control for prevention of anastomotic leakage after resection for rectal cancer (RIPAL trial): a pilot randomized controlled, triple-blinded monocenter trial

PurposeRemote ischemic preconditioning (RIPC) reportedly reduces ischemia‒reperfusion injury (IRI) in various organ systems. In addition to tension and technical factors, ischemia is a common cause of anastomotic leakage (AL) after rectal resection. The aim of this pilot study was to investigate the potentially protective effect of RIPC on anastomotic healing and to determine the effect size to facilitate the development of a subsequent confirmatory trial.Materials and methodsFifty-four patients with rectal cancer (RC) who underwent anterior resection were enrolled in this prospectively registered (DRKS0001894) pilot randomized controlled triple-blinded monocenter trial at the Department of Surgery, University Medicine Mannheim, Mannheim, Germany, between 10/12/2019 and 19/06/2022. The primary endpoint was AL within 30 days after surgery. The secondary endpoints were perioperative morbidity and mortality, reintervention, hospital stay, readmission and biomarkers of ischemia‒reperfusion injury (vascular endothelial growth factor, VEGF) and cell death (high mobility group box 1 protein, HMGB1). RIPC was induced through three 10-min cycles of alternating ischemia and reperfusion to the upper extremity.ResultsOf the 207 patients assessed, 153 were excluded, leaving 54 patients to be randomized to the RIPC or the sham-RIPC arm (27 each per arm). The mean age was 61 years, and the majority of patients were male (37:17 (68.5:31.5%)). Most of the patients underwent surgery after neoadjuvant therapy (29/54 (53.7%)) for adenocarcinoma (52/54 (96.3%)). The primary endpoint, AL, occurred almost equally frequently in both arms (RIPC arm: 4/25 (16%), sham arm: 4/26 (15.4%), p = 1.000). The secondary outcomes were comparable except for a greater rate of reintervention in the sham arm (9 (6–12) vs. 3 (1–5), p = 0.034). The median duration of endoscopic vacuum therapy was shorter in the RIPC arm (10.5 (10–11) vs. 38 (24–39) days, p = 0.083), although the difference was not statistically significant.ConclusionA clinically relevant protective effect of RIPC on anastomotic healing after rectal resection cannot be assumed on the basis of these data.

Neuroprotective effect of ischemic postconditioning against hyperperfusion and its mechanisms of neuroprotection.

In recent years, stroke and ischemia-reperfusion injury has motivated researchers to find new ways to reduce the complications. Although reperfusion is essential for brain survival, it is like a double-edged sword that may cause further damage to the brain. Ischemic postconditioning (IPostC) refers to the control of blood flow in postischemia-reperfusion that can reduce ischemia-reperfusion injuries. Articles were collected by searching for the terms: Ischemic postconditioning and neuroprotective and ischemic postconditioning and hyperperfusion. Suitable articles were collected from electronic databases, including ISI Web of Knowledge, Medline/PubMed, ScienceDirect, Embase, Scopus, Biological Abstract, Chemical Abstract, and Google Scholar. New investigations show that IPostC has protection against hyperperfusion by reducing the amount of blood flow during reperfusion and thus reducing infarction volume, preventing the blood-brain barrier damage, and reducing the rate of apoptosis through the activation of innate protective systems. Numerous mechanisms have been suggested for IPostC, which include reduction of free radical production, apoptosis, inflammatory factors, and activation of endogenous protective pathways. It seems that postconditioning can prevent damage to the brain by reducing the flow and blood pressure caused by hyperperfusion. It can protect the brain against damages such as stroke and hyperperfusion by activating various endogenous protection systems. In the present review article, we tried to evaluate both useful aspects of IPostC, neuroprotective effects, and fight against hyperperfusion.

Experimental study on the preservation of amputated limb by low-temperature HTK preservation solution arterial perfusion

Objective: To evaluate the effect of HTK (Histidine-Tryptophan-Ketoglutarate solution) infusion on the protection and replantation of amputated limb. Methods: In experiment 1, the amputated limbs of male New Zealand white rabbits were preserved by different preservation methods, including low-temperature HTK solution perfusion group, low-temperature normal saline perfusion group, low-temperature preservation group and non-perfusion group at normal temperature. The homogenates of muscle tissue at different time points were collected for biochemical detection. H&amp;E (hematoxylin and eosin) staining was performed on muscle tissue. Bax, Bcl-2 protein immunohistochemical staining and Tunel method were used to detect apoptosis in muscle, nerve, and vascular tissues. The ultrastructure of cells was observed by transmission electron microscope. In experiment 2, the amputated limbs of rabbits were treated with HTK perfusion and cryopreservation without perfusion, respectively. The survival of rabbits and their limbs were observed, and detected by H&amp;E, TUNEL (Terminal deoxynucleotidyl transferase dUTP Nick End Labeling) and scanning electron microscopy. Statistical analysis was performed using SPSS 22 (SPSS Inc., Chicago, IL, USA). χ2 test, student’s t-test, and ANOVA (Analysis of Variance) were used to compare the categorical and continuous variables. Results: Experiment 1: With the extension of disconnection time, there were statistical differences between the biochemical indexes of the HTK liquid perfusion group and those of the non-low temperature non-perfusion group, while some indexes of the other groups were different. Immunohistochemical staining of tissues (muscle, nerve, and blood vessel) in each group showed that the number of cells stained by anti-apoptotic protein BCL-2 in each group significantly increased with the extension of time, while the number of cells stained by pro-apoptotic protein BAX2 in each group significantly decreased. Tunel test showed that compared with other treatment groups, the apoptosis rate of the HTK liquid group was significantly decreased. Experiment 2: The survival rate of the experimental group was 60%, and that of the control group was only 30%. H&amp;E staining, the TUNEL method and scanning electron microscopy suggested that HTK infusion could reduce ischemia-reperfusion injury in muscle tissue. Conclusion: 1. Perfusion preservation of severed limbs at 4 ℃ can effectively reduce tissue damage caused by ischemia and hypoxia, and the effect is stronger than direct preservation. 2. HTK solution and normal saline were used for one-time perfusion of the severed limbs of rabbits, and the preservation effect of HTK solution was the best. 3. HTK solution was used for one-time perfusion of severed hind limbs of rabbits, which was refrigerated at 4 ℃ and then replanted (ischemia time was 3–5 h). Compared with the replanted limbs after cold storage alone, the survival rate was higher, and the postoperative ischemia and hypoxia injury of surviving limbs were less.

Pretreatment with a dual antiplatelet and anticoagulant (APAC) reduces ischemia–reperfusion injury in a mouse model of temporary middle cerebral artery occlusion—implications for neurovascular procedures

BackgroundSeveral neurovascular procedures require temporary occlusion of cerebral arteries, leading to ischemia of unpredictable length, occasionally causing brain infarction. Experimental models of cerebral ischemia–reperfusion injury have established that platelet adhesion and coagulation play detrimental roles in reperfusion injury following transient cerebral ischemia. Therefore, in a model of cerebral ischemia–reperfusion injury (IRI), we investigated the therapeutic potential of a dual antiplatelet and anticoagulant (APAC) heparin proteoglycan mimetic which is able to bind to vascular injury sites.MethodsBrain ischemia was induced in mice by transient occlusion of the right middle cerebral artery for 60 min. APAC, unfractionated heparin (UFH) (both at heparin equivalent doses of 0.5 mg/kg), or vehicle was intravenously administered 10 min before or 60 min after the start of ischemia. At 24 h later, mice were scored for their neurological and motor behavior, and brain damage was quantified.ResultsBoth APAC and UFH administered before the onset of ischemia reduced brain injury. APAC and UFH pretreated mice had better neurological and motor functions (p < 0.05 and p < 0.01, respectively) and had significantly reduced cerebral infarct sizes (p < 0.01 and p < 0.001, respectively) at 24 h after transient occlusion compared with vehicle-treated mice. Importantly, no macroscopic bleeding complications were observed in either APAC- or UFH-treated animals. However, when APAC or UFH was administered 60 min after the start of ischemia, the therapeutic effect was lost, but without hemorrhaging either.ConclusionsPretreatment with APAC or UFH was safe and effective in reducing brain injury in a model of cerebral ischemia induced by transient middle cerebral artery occlusion. Further studies on the use of APAC to limit ischemic injury during temporary occlusion in neurovascular procedures are indicated.

Ex Vivo Optimization of Donor Lungs with Inhaled Sevoflurane during Normothermic Ex Vivo Lung Perfusion (VITALISE): A Pilot and Feasibility Study in Sheep.

Volatile anesthetics have been shown in different studies to reduce ischemia reperfusion injury (IRI). Ex vivo lung perfusion (EVLP) facilitates graft evaluation, extends preservation time and potentially enables injury repair and improvement of lung quality. We hypothesized that ventilating lungs with sevoflurane during EVLP would reduce lung injury and improve lung function. We performed a pilot study to test this hypothesis in a slaughterhouse sheep DCD model. Lungs were harvested, flushed and stored on ice for 3 h, after which EVLP was performed for 4 h. Lungs were ventilated with either an FiO2 of 0.4 (EVLP, n = 5) or FiO2 of 0.4 plus sevoflurane at a 2% end-tidal concentration (Cet) (S-EVLP, n = 5). Perfusate, tissue samples and functional measurements were collected and analyzed. A steady state of the target Cet sevoflurane was reached with measurable concentrations in perfusate. Lungs in the S-EVLP group showed significantly better dynamic lung compliance than those in the EVLP group (p = 0.003). Oxygenation capacity was not different in treated lungs for delta partial oxygen pressure (PO2; +3.8 (-4.9/11.1) vs. -11.7 (-12.0/-3.2) kPa, p = 0.151), but there was a trend of a better PO2/FiO2 ratio (p = 0.054). Perfusate ASAT levels in S-EVLP were significantly reduced compared to the control group (198.1 ± 93.66 vs. 223.9 ± 105.7 IU/L, p = 0.02). We conclude that ventilating lungs with sevoflurane during EVLP is feasible and could be useful to improve graft function.