Systematic review of randomized controlled trials of pharmacological interventions to reduce ischaemia-reperfusion injury in elective liver resection with vascular occlusion

Protective Effects of Trimetazidine and Dexmedetomidine on Liver Injury in a Mesenteric Artery Ischemia-Reperfusion Rat Model via Endoplasmic Reticulum Stress

BACKGROUND/OBJECTIVES

Acute mesenteric ischemia can lead to severe liver damage due to ischemia-reperfusion (I/R) injury. This study investigated the protective effects of trimetazidine (TMZ) and dexmedetomidine (DEX) against liver damage induced by mesenteric artery I/R via endoplasmic reticulum stress (ERS) mechanisms.

METHODS

Twenty-four rats were divided into four groups: control, I/R, I/R+TMZ, and I/R+DEX. TMZ (20 mg/kg) was administered orally for seven days, and DEX (100 µg/kg) was given intraper-itoneally 30 min before I/R induction. Liver tissues were analyzed for creatinine, alanine ami-notransferase (ALT), aspartate aminotransferase (AST), thiobarbituric acid reactive substances (TBARS), and total thiol (TT) levels.

RESULTS

Compared with the control group, the I/R group presented significantly increased AST, ALT, TBARS, and TT levels. TMZ notably reduced creatinine levels. I/R caused significant liver necrosis, inflammation, and congestion. TMZ and DEX treatments reduced this histopathological damage, with DEX resulting in a more significant reduction in infiltrative areas and vascular congestion. The increase in the expression of caspase-3, Bax, 8-OHdG, C/EBP homologous protein (CHOP), and glucose-regulated protein 78 (GRP78) decreased with the TMZ and DEX treatments. In addition, Bcl-2 positivity decreased both in the TMZ and DEX treatments.

CONCLUSIONS

Both TMZ and DEX have protective effects against liver damage. These effects are likely mediated through the reduction in ERS and apoptosis, with DEX showing slightly superior protective effects compared with TMZ.

Effect of inferior vena cava respiratory variability-guided fluid therapy after laparoscopic hepatectomy: a randomized controlled clinical trial

BACKGROUND

After major liver resection, the volume status of patients is still undetermined. However, few concerns have been raised about postoperative fluid management. We aimed to compare gut function recovery and short-term prognosis of the patients after laparoscopic liver resection (LLR) with or without inferior vena cava (IVC) respiratory variability-directed fluid therapy in the anesthesia intensive care unit (AICU).

METHODS

This randomized controlled clinical trial enrolled 70 patients undergoing LLR. The IVC respiratory variability was used to optimize fluid management of the intervention group in AICU, while the standard practice of fluid management was used for the control group. The primary outcome was the time to flatus after surgery. The secondary outcomes included other indicators of gut function recovery after surgery, postoperative length of hospital stay (LOS), liver and kidney function, the severity of oxidative stress, and the incidence of severe complications associated with hepatectomy.

RESULTS

Compared with patients receiving standard fluid management, patients in the intervention group had a shorter time to anal exhaust after surgery (1.5 ± 0.6 days vs. 2.0 ± 0.8 days) and lower C-reactive protein activity (21.4 [95% confidence interval (CI): 11.9-36.7] mg/L vs. 44.8 [95%CI: 26.9-63.1] mg/L) 24 h after surgery. There were no significant differences in the time to defecation, serum concentrations of D-lactic acid, malondialdehyde, renal function, and frequency of severe postoperative complications as well as the LOS between the groups.

CONCLUSION

Postoperative IVC respiratory variability-directed fluid therapy in AICU was facilitated in bowel movement but elicited a negligible beneficial effect on the short-term prognosis of patients undergoing LLR.

TRIAL REGISTRATION

ChiCTR-INR-17013093.

Impact of perioperative steroid administration in patients undergoing elective liver resection: meta-analysis

BACKGROUND

Perioperative steroid administration may improve postoperative outcomes in major abdominal surgery by reducing the systemic inflammatory response. The aim of this systematic review was to evaluate the impact of perioperative steroid administration on outcomes after elective liver resection.

METHODS

PubMed, Cochrane Library, and Web of Science were systematically searched for randomized clinical trials (RCTs) comparing perioperative steroid administration with placebo, standard of care, or no steroids with respect to postoperative outcomes, particularly postoperative complications. Two independent reviewers critically appraised the studies and extracted data. Meta-analyses were performed using a random-effects model with ORs calculated for dichotomous outcomes and mean differences (MDs) for continuous outcomes.

RESULTS

Ten RCTs comprising 930 patients were included. Perioperative steroid administration significantly reduced the overall postoperative complication rate (OR 0.61, 95 per cent c.i. 0.43 to 0.87; P = 0.006; I2 = 26 per cent). No significant differences were shown for individual complications. Several postoperative laboratory parameters were positively affected, like total serum bilirubin (MD -0.46; 95 per cent c.i. -0.74 to -0.18; P = 0.001; I2 = 80 per cent), interleukin 6 (MD -48.99; 95 per cent c.i. -60.72 to -37.27; P < 0.001; I2 = 0 per cent) and C-reactive protein (MD -5.20; 95 per cent c.i. -7.62 to -2.77; P < 0.001; I2 = 71 per cent). There were no signs of an increase in potential steroid-induced adverse events, namely infectious complications, thromboembolic events, or bleeding.

CONCLUSIONS

Perioperative steroid administration significantly reduces the overall complication rate after elective liver resection without an increased risk of adverse effects.

S-15176 Difumarate Salt Can Impair Mitochondrial Function through Inhibition of the Respiratory Complex III and Permeabilization of the Inner Mitochondrial Membrane

S-15176 difumarate salt, a derivative of the anti-ischemic metabolic drug trimetazidine, has been intensively studied for its impact on cellular metabolism in animal models of ischemia-reperfusion injury of the liver, heart, spinal cord, and other organs. Despite evidence of some reduction in oxidative damage to cells, the results of therapy with S-15176 have been mostly disappointing, possibly because of the lack of data on its underlying mechanisms. Here, we aimed to investigate in more detail the role of complexes I-IV of the electron transport chain and membrane permeability transition in mitochondrial toxicity associated with S-15176. Using rat thymocyte and liver mitochondria, we demonstrated that: (1) acute exposure to S-15176 (10 to 50 μM) dose-dependently decreased the mitochondrial membrane potential; (2) S-15176 suppressed the ADP-stimulated (State 3) and uncoupled (State 3UDNP) respiration of mitochondria energized with succinate or malate/glutamate, but not ascorbate/TMPD, and increased the resting respiration (State 4) when using all the substrate combinations; (3) S-15176 directly inhibited the activity of the respiratory complex III; (4) low doses of S-15176 diminished the rate of H2O2 production by mitochondria; (5) at concentrations of above 30 μM, S-15176 reduced calcium retention capacity and contributed to mitochondrial membrane permeabilization. Taken together, these findings suggest that S-15176 at tissue concentrations reached in animals can impair mitochondrial function through suppression of the cytochrome bc1 complex and an increase in the nonspecific membrane permeability.

Methods of Attenuating Ischemia-Reperfusion Injury in Liver Transplantation for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most frequent indications for liver transplantation. However, the transplantation is ultimately associated with the occurrence of ischemia-reperfusion injury (IRI). It affects not only the function of the graft but also significantly worsens the oncological results. Various methods have been used so far to manage IRI. These include the non-invasive approach (pharmacotherapy) and more advanced options encompassing various types of liver conditioning and machine perfusion. Strategies aimed at shortening ischemic times and better organ allocation pathways are still under development as well. This article presents the mechanisms responsible for IRI, its impact on treatment outcomes, and strategies to mitigate it. An extensive review of the relevant literature using MEDLINE (PubMed) and Scopus databases until September 2020 was conducted. Only full-text articles written in English were included. The following search terms were used: “ischemia reperfusion injury”, “liver transplantation”, “hepatocellular carcinoma”, “preconditioning”, “machine perfusion”.

Interpatient heterogeneity in hepatic microvascular blood flow during vascular inflow occlusion (Pringle manoeuvre)

BACKGROUND

Vascular inflow occlusion (VIO) during liver resections (Pringle manoeuvre) can be applied to reduce blood loss, however may at the same time, give rise to ischemia-reperfusion injury (IRI). The aim of this study was to assess the characteristics of hepatic microvascular perfusion during VIO in patients undergoing major liver resection.

METHODS

Assessment of hepatic microcirculation was performed using a handheld vital microscope (HVM) at the beginning of surgery, end of VIO (20 minutes) and during reperfusion after the termination of VIO. The microcirculatory parameters assessed were: functional capillary density (FCD), microvascular flow index (MFI) and sinusoidal diameter (SinD).

RESULTS

A total of 15 patients underwent VIO; 8 patients showed hepatic microvascular perfusion despite VIO (partial responders) and 7 patients showed complete cessation of hepatic microvascular perfusion (full responders). Functional microvascular parameters and blood flow levels were significantly higher in the partial responders when compared to the full responders during VIO (FCD: 0.84±0.88 vs. 0.00±0.00 mm/mm2, P<0.03, respectively, and MFI: 0.69-0.22 vs. 0.00±0.00, P<0.01, respectively).

CONCLUSIONS

An interpatient heterogeneous response in hepatic microvascular blood flow was observed upon VIO. This may explain why clinical strategies to protect the liver against IRI lacked consistency.

Ischemia/Reperfusion Injury Revisited: An Overview of the Latest Pharmacological Strategies

Ischemia/reperfusion injury (IRI) permeates a variety of diseases and is a ubiquitous concern in every transplantation proceeding, from whole organs to modest grafts. Given its significance, efforts to evade the damaging effects of both ischemia and reperfusion are abundant in the literature and they consist of several strategies, such as applying pre-ischemic conditioning protocols, improving protection from preservation solutions, thus providing extended cold ischemia time and so on. In this review, we describe many of the latest pharmacological approaches that have been proven effective against IRI, while also revisiting well-established concepts and presenting recent pathophysiological findings in this ever-expanding field. A plethora of promising protocols has emerged in the last few years. They have been showing exciting results regarding protection against IRI by employing drugs that engage several strategies, such as modulating cell-surviving pathways, evading oxidative damage, physically protecting cell membrane integrity, and enhancing cell energetics.

Perioperative Management in Hepatic Resections: Comparative Effectiveness of Neuraxial Anesthesia and Disparity of Care Patterns

BACKGROUND

Complication rates after hepatic resection can be affected by management decisions of the hospital care team and/or disparities in care. This is true in many other surgical populations, but little study has been done regarding patients undergoing hepatectomy.

METHODS

Data from the claims-based national Premier Perspective database were used for 2006 to 2014. The analytical sample consisted of adults undergoing partial hepatectomy and total hepatic lobectomy with anesthesia care consisting of general anesthesia (GA) only or neuraxial and GA (n = 9442). The key independent variable was type of anesthesia that was categorized as GA versus GA + neuraxial. The outcomes examined were clinical complications and health care resource utilization. Unadjusted bivariate and adjusted multivariate analyses were conducted to examine the effects of the different types of anesthesia on clinical complications and health care resource utilization after controlling for patient- and hospital-level characteristics.

RESULTS

Approximately 9% of patients were provided with GA + neuraxial anesthesia during hepatic resection. In multivariate analyses, no association was observed between types of anesthesia and clinical complications and/or health care utilization (eg, admission to intensive care unit). However, patients who received blood transfusions were significantly more likely to have complications and intensive care unit stays. In addition, certain disparities of care, including having surgery in a rural hospital, were associated with poorer outcomes.

CONCLUSIONS

Neuraxial anesthesia utilization was not associated with improvement in clinical outcome or cost among patients undergoing hepatic resections when compared to patients receiving GA alone. Future research may focus on prospective data sources with more clinical information on such patients and examine the effects of GA + neuraxial anesthesia on various complications and health care resource utilization.

Cytidine-5'-Diphosphocholine Protects the Liver From Ischemia/Reperfusion Injury Preserving Mitochondrial Function and Reducing Oxidative Stress

Cytidine-5'-diphosphocholine (CDP-choline) participates as an intermediary in the synthesis of phosphatidylcholine, an essential component of cellular membranes. Citicoline treatment has shown beneficial effects in cerebral ischemia, but its potential to diminish reperfusion damage in liver has not been explored. In this work, we evaluated the hepatoprotective effect of citicoline and its possible association with inflammatory/oxidative stress and mitochondrial function because they are the main cellular features of reperfusion damage. Ischemia/reperfusion (I/R) in rat livers was performed with the Pringle's maneuver, clamping the 3 elements of the pedicle (hepatic artery, portal vein, and biliary tract) for 30 minutes and then removing the clamp to allow hepatic reperfusion for 60 minutes. The I/R + citicoline group received the compound before I/R. Liver injury was evaluated by measuring aspartate aminotransferase and alanine aminotransferase as well as lactic acid levels in serum; proinflammatory cytokines, proresolving lipid mediators, and nuclear factor kappa B content were determined as indicators of the inflammatory response. Antioxidant effects were evaluated by measuring markers of oxidative stress and antioxidant molecules. Oxygen consumption and the activities of the respiratory chain were used to monitor mitochondrial function. CDP-choline reduced aspartate aminotransferase (AST), alanine aminotransferase (ALT), as well as lactic acid levels in blood samples from reperfused rats. Diminution in tumor necrosis factor alpha (TNF-α) and increase in the proresolving lipid mediator resolvin D1 were also observed in the I/R+citicoline group, in comparison with the I/R group. Oxidative/nitroxidative stress in hepatic mitochondria concurred with deregulation of oxidative phosphorylation, which was associated with the loss of complex III and complex IV activities. In conclusion, CDP-choline attenuates liver damage caused by ischemia and reperfusion by reducing oxidative stress and maintaining mitochondrial function. Liver Transplantation XX XX-XX 2018 AASLD.

Unacylated ghrelin prevents mitochondrial dysfunction in a model of ischemia/reperfusion liver injury

Ischemia/reperfusion (I/R) injury is a common cause of liver dysfunction during hepatectomy, liver transplantation procedures and in generalized shock. Although effort has been dedicated to rescuing tissue damage in these clinical settings, there is still an urgent need for an effective treatment to protect the liver from the burden of I/R injury. In this study, we have investigated the potential clinical impact of unacylated-ghrelin (UnAG) in a liver I/R rat model. Particular attention has been paid to mitochondria. We demonstrate that UnAG was able to reduce the lag-phase time in response to ADP administration and increase oxygen consumption in ex vivo experiments using liver mitochondria recovered from rats subjected to I/R. Moreover, we found that UnAG rescued the expression of a key regulator of mitochondrial morphology and electron transport chain function; the optic atrophy 1 (Opa1) protein. Cytochrome c oxidase (COX), ATP synthase (complex V) activity and mitochondrial permeability transition pore (mPTP) opening were also affected by UnAG administration in vivo. An in vitro, hepatic I/R model was used to validate these data. We demonstrate that UnAG upregulates the expression of Cox subunit IV (CoxIV) and increases cellular ATP content. This results in Bcl-2 upregulation and protection against apoptosis. Opa1 silencing shows that Opa1 is crucial for a UnAG-induced increase in cellular ATP content, apoptosis resistance, Bcl-2 and CoxIV expression. Finally, we show that UnAG improves Opa1's interaction with MIC60 in the I/R setting, hinting at its role in cristae shape regulation. Our results demonstrate that UnAG administration rescues the intrinsic mitochondrial pathway triggered by I/R damage. Opa1's contribution in mediating this effect is also reported. This suggests that UnAG can interfere with mitochondrial dysfunction, via Opa1, in a preclinical liver I/R model. We therefore provide the rationale for exploiting UnAG as an alternative means to rescuing mitochondrial damage and organ dysfunction.

microRNA-183 Mediates Protective Postconditioning of the Liver by Repressing Apaf-1

AIMS

Ischemic postconditioning (iPoC) is known to mitigate ischemia-reperfusion (IR) injury of the liver, the mechanisms of which remain to be elucidated. This study explored the role of microRNA-183 (miR-183) in the protective mechanism of iPoC.

RESULTS

Microarray analysis showed miR-183 was robustly expressed in rats' livers with iPoC. miR-183 repressed the mRNA expression of Apaf-1, which is an apoptosis promoting factor. Using an oxygen-glucose deprivation (OGD) injury model in Clone 9 cells, hypoxic postconditioning (HPoC) and an miR-183 mimetic significantly decreased cell death after OGD, but miR-183 inhibitors eliminated the protection of HPoC. The increased expression of Apaf-1 and the downstream activation of capsase-3/9 after OGD were mitigated by HPoC or the addition of miR-183 mimetics, whereas miR-183 inhibitor diminished the effect of HPoC on Apaf-1-caspase signaling. In the in vivo experiment, iPoC and agomiR-183 decreased the expression of serum ALT after liver IR in the mice, but antagomiR-183 mitigated the effect of iPoC. The results of hematoxylin and eosin and TUNEL staining were compatible with the biochemical assay. Moreover, iPoC and agomiR-183 decreased the expression of Apaf-1 and 4-HNE after IR injury in mouse livers, whereas the antagomiR-mediated prevention of miR-183 expression led to increased protein expression of Apaf-1 and 4-HNE in the postischemic livers.

INNOVATION

Our experiment showed the first time that miR-183 was induced in protective postconditioning and reduced reperfusion injury of the livers via the targeting of apoptotic signaling.

CONCLUSION

miR-183 mediated the tolerance induced by iPoC in livers via Apaf-1 repressing. Antioxid. Redox Signal. 26, 583-597.

The hypoxanthine-xanthine oxidase axis is not involved in the initial phase of clinical transplantation-related ischemia-reperfusion injury

The hypoxanthine-xanthine oxidase (XO) axis is considered to be a key driver of transplantation-related ischemia-reperfusion (I/R) injury. Whereas interference with this axis effectively quenches I/R injury in preclinical models, there is limited efficacy of XO inhibitors in clinical trials. In this context, we considered clinical evaluation of a role for the hypoxanthine-XO axis in human I/R to be relevant. Patients undergoing renal allograft transplantation were included (n = 40) and classified based on duration of ischemia (short, intermediate, and prolonged). Purine metabolites excreted by the reperfused kidney (arteriovenous differences) were analyzed by the ultra performance liquid chromatography-tandem mass spectrometer (UPLCMS/MS) method and tissue XO activity was assessed by in situ enzymography. We confirmed progressive hypoxanthine accumulation (P < 0.006) during ischemia, using kidney transplantation as a clinical model of I/R. Yet, arteriovenous concentration differences of uric acid and in situ enzymography of XO did not indicate significant XO activity in ischemic and reperfused kidney grafts. Furthermore, we tested a putative association between hypoxanthine accumulation and renal oxidative stress by assessing renal malondialdehyde and isoprostane levels and allantoin formation during the reperfusion period. Absent release of these markers is not consistent with an association between ischemic hypoxanthine accumulation and postreperfusion oxidative stress. On basis of these data for the human kidney we hypothesize that the role for the hypoxanthine-XO axis in clinical I/R injury is less than commonly thought, and as such the data provide an explanation for the apparent limited clinical efficacy of XO inhibitors.

Continuous infusion of high-dose ulinastatin during surgery does not improve early postoperative clinical outcomes in patients undergoing radical lung cancer surgery: A pilot study

Background

Ulinastatin can prevent the perioperative increase in proinflammatory cytokines for lung resection surgery; however, its impact on early clinical outcomes remains unknown.

Methods

The study enrolled 108 non‐small cell lung cancer (NSCLC) patients who were randomly allocated into two groups: ulinastatin (group U) and control (group C). Patients in group U (n = 52) were continuously intravenously infused with ulinastatin at a rate of 20 000 U/kg/hour for the first hour after anesthesia induction, and then at a rate of 5000 U/kg/hour until the conclusion of surgery. Patients in group C (n = 56) received an equivalent volume of normal saline. The primary outcome was to record the postoperative pulmonary complications that occurred during hospital stay. Other clinical courses, such as hospital mortality, blood loss, respiratory parameters, postoperative chest drainage, and duration of intensive care unit and postoperative hospital stay, were also observed and analyzed.

Results

There were no significant differences between the two groups in early postoperative pulmonary complications, hospital mortality, blood loss, or other perioperative laboratory values, except for the duration of postoperative chest drainage and serum creatinine level. The frequency of pulmonary complications was lower in patients treated with ulinastatin compared with the control (38.46% in group U vs. 48.21% in group C).

Conclusion

Administration of high‐dose ulinastatin during surgery did not reduce postoperative pulmonary complications, hospital mortality, or hospital stay for patients undergoing lung radical thoracotomy. However, a protective trend of ulinastatin was observed.

Hypoxemic reperfusion of ischemic states: an alternative approach for the attenuation of oxidative stress mediated reperfusion injury

Ischemia and reperfusion (I/R) - induced injury has been described as one of the main factors that contribute to the observed morbidity and mortality in a variety of clinical entities, including myocardial infarction, ischemic stroke, cardiac arrest and trauma. An imbalance between oxygen demand and supply, within the organ beds during ischemia, results in profound tissue hypoxia. The subsequent abrupt oxygen re-entry upon reperfusion, may lead to a burst of oxidative aggression through production of reactive oxygen species by the primed cells. The predominant role of oxidative stress in the pathophysiology of I/R mediated injury, has been well established. A number of strategies that target the attenuation of the oxidative burst have been tested both in the experimental and the clinical setting. Despite these advances, I/R injury continues to be a major problem in everyday medical practice. The aim of this paper is to review the existing literature regarding an alternative approach, termed hypoxemic reperfusion, that has exhibited promising results in the attenuation of I/R injury, both in the experimental and the clinical setting. Further research to clarify its underlying mechanisms and to assess its efficacy in the clinical setting is warranted.

Role of ischemic preconditioning in hepatic ischemia-reperfusion injury

BACKGROUND

Investigation into less traumatic method of vascular occlusion during liver resection is the actual problem in hepatic surgery because of high level of complications such as liver failure. In this connection, the goal of our study was to determine the optimal model of vascular clamping. The research showed that vascular occlusion with ischemic preconditioning in the mode 5/10/15 the most delicate technique.

METHODS

Forty white giant rabbits were divided randomly into four groups (n=10 in each group). In group I we used continuous Pringle maneuver by 30 min. In group II we used intermittent Pringle maneuver: 15 min of clamping/5 min of unclamping (reperfusion)/15 min of clamping. In group III we used intermittent Pringle maneuver with ischemic precondition: 5 min of ischemia/5 min of reperfusion, 10 min of ischemia/5 min of reperfusion/15 min of ischemia. Group IV (control group) is without hepatic ischemia. All animals were performed a liver biopsy at the end of the surgery. Five rabbits from each group underwent re-laparotomy on day 3 after surgery with biopsy samples being taken for studying reparative processes in liver parenchyma.

RESULTS

Results of morphometric analysis were the best to illustrate different level of liver injury in the groups. Thus, there were 95.5% damaged hepatocytes after vascular occlusion in hepatic preparations in group I, 70.3% damaged hepatocytes in group II, and 42.3% damaged hepatocytes in group III. There were 5.3% damaged hepatocytes in the control group.

CONCLUSIONS

Vascular occlusion with ischemic preconditioning in the mode 5/10/15 the most delicate technique that does not involve major structural injuries and functional disorders in the remnant liver. Thus, it is amenable to translation into clinical practice and may improve outcomes in liver resection with inflow vascular occlusion.

Magnesium isoglycyrrhizinate protects hepatic L02 cells from ischemia/reperfusion induced injury

Human liver ischemia/reperfusion injury (IRI) is a common and major clinical problem complicating liver surgery and transplantation. The pathogenesis underlying IRI is complex, involving a series of signaling mediators and mechanisms. This study aimed to investigate the effects of Magnesium Isoglycyrrhizinate (MgIG) on the changes of oxidant stress and apoptosis induced by IRI in human hepatic L02 cells. L02 cells with IRI were treated with or without MgIG and mitoKATP (Mitochondrial adenosine triphosphate-dependent potassium) channel modulators. Cell viability was assessed using CCK-8 assay. Cell apoptosis was quantified by flow cytometry. The activity of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were measured. Effects of MgIG on the expression of Bax, Bcl-2, Caspase 3, PARP (poly ADP-ribose polymerase), Akt, and ERK in L02 cells with IRI were examined. Our results showed that MgIG treatment significantly reduced the population of apoptotic cells and the expression of apoptosis-related proteins in hepatic L02 cells with IRI. MgIG also counteract ischemia reperfusion induced oxidative challenge as it effectively reduced malondialdehyde (MDA) and increased the activities of SOD and GSH-Px. L02 cells treated with MgIG showed increased expression of p-Akt and p-ERK, indicating that the protective effect of MgIG might be associated with the activation of Akt and ERK pathways. Moreover, the addition of Diazoxide (DE), a mitoKATP channel opener, enhanced the cytoprotective activity of MgIG, while the mitoKATP blocker 5-hydroxydecanoate (5-HD) reduced the cytoprotective activity of MgIG.

Rodent models of hepatic ischemia-reperfusion injury: time and percentage-related pathophysiological mechanisms

Ischemia and reperfusion (IR) injury remains one of the major problems in liver surgery and transplantation, which determines the viability of the hepatic tissue after resection and of the grafted organ. This review aims to elucidate the mechanisms involved in IR injury of the liver in rodent experimental studies and the preventative methods and pharmacologic agents that have been applied. Many time- and percentage-related liver IR injury rodent models have been used to examine the pathophysiological mechanisms and the parameters implicated with different morbidity, mortality, and pathology findings. The most preferred experimental rodent model of liver IR is the induction of 70% IR for 45 min, which is associated with almost 100% survival. In this model, plasma levels of several parameters such as alanine transaminase, aspartate aminotransferase, gamma-glutamyltransferase, endothelin-1, malonodialdehyde, tumor necrosis factor α, interleukin 1b, inducible nitric oxide synthase, and caspases are increased. The increase of caspases is associated with the initiation of hepatic cellular apoptosis. The main injuries observed 24 h after reperfusion are nuclear pyknosis, cytoplasmic hypereosinophilia, severe necrosis, and loss of intercellular borders. Both ischemic pre- and post-conditioning preventative methods and pharmacologic agents are successfully applied to alleviate the IR injuries. The selection of the time- and percentage-related liver IR injury rodent model and the potential preventative method should be related to the clinical question being answered.

Epigallocatechin gallate does not accelerate the early phase of liver regeneration after partial hepatectomy in rats

BACKGROUND

Two-thirds partial hepatectomy (PHx) is an established model for the study of liver regeneration after resection. This process is accompanied by oxidative stress.

AIMS

In our study, we tested the effect of epigallocatechin gallate (EGCG), a green tea antioxidant, on the early phase of liver regeneration after PHx.

METHODS

Male Wistar rats were divided into five groups: (I) laparotomy + water for intraperitoneal injections, (II) laparotomy + EGCG 50 mg/kg body weight, (III) PHx + water for injections, (IV) PHx + EGCG 20 mg/kg and (V) PHx + EGCG 50 mg/kg, for 3 consecutive days. The rats were killed 24 h after surgery. Biochemical analysis of rat sera was performed. Histological samples were stained with hematoxylin & eosin and bromodeoxyuridine (BrdU). In hepatectomized rats, we also measured plasma malondialdehyde, tissue malondialdehyde, glutathione and cytokines levels, the activity of caspases 3/7, expression of Nqo-1 and HO-1 genes at the mRNA level, and expression of p21, p-p27 and p-p53 genes at the protein level.

RESULTS

We observed lower accumulation of BrdU in group V when compared to groups III and IV. The activity of caspases 3/7 and expression of p-p53 were lower in group V than in groups III and IV. Tissue levels of IL-6 were lower in group V when compared to group III. Significant differences were not noted in other parameters.

CONCLUSIONS

Administration of EGCG did not stimulate early phase liver regeneration in rats after PHx. There was even lower DNA synthesis in the group treated with a high dose of EGCG.

Use of pre-operative steroids in liver resection: a systematic review and meta-analysis

BACKGROUND

By attenuating the systemic inflammatory response to major surgery, the pre-operative administration of steroids may reduce the incidence of complications.

METHODS

A systematic review was conducted to identify randomized controlled trials (RCT) comparing pre-operative steroid administration with placebo during a liver resection. Meta-analyses were performed.

RESULTS

Five RCTs were identified including a total of 379 patients. Pre-operative steroids were associated with statistically significant reductions in the levels of serum bilirubin and interleukin 6 (IL-6) on post-operative day one. There was a trend towards a lower incidence of post-operative complications and prothrombin time (PT), but this did not reach statistical significance.

CONCLUSION

Pre-operative steroids may be associated with a clinically significant benefit in liver resection.

Ulinastatin attenuates oxidation, inflammation and neural apoptosis in the cerebral cortex of adult rats with ventricular fibrillation after cardiopulmonary resuscitation

OBJECTIVE

The role of Ulinastatin in neuronal injury after cardiopulmonary resuscitation has not been elucidated. We aim to evaluate the effects of Ulinastatin on inflammation, oxidation, and neuronal injury in the cerebral cortex after cardiopulmonary resuscitation.

METHODS

Ventricular fibrillation was induced in 76 adult male Wistar rats for 6 min, after which cardiopulmonary resuscitation was initiated. After spontaneous circulation returned, the rats were split into two groups: the Ulinastatin 100,000 unit/kg group or the PBS-treated control group. Blood and cerebral cortex samples were obtained and compared at 2, 4, and 8 h after return of spontaneous circulation. The protein levels of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) were assayed using an enzyme-linked immunosorbent assay, and mRNA levels were quantified via real-time polymerase chain reaction. Myeloperoxidase and Malondialdehyde were measured by spectrophotometry. The translocation of nuclear factor-κB p65 was assayed by Western blot. The viable and apoptotic neurons were detected by Nissl and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL).

RESULTS

Ulinastatin treatment decreased plasma levels of TNF-α and IL-6, expression of mRNA, and Myeloperoxidase and Malondialdehyde in the cerebral cortex. In addition, Ulinastatin attenuated the translocation of nuclear factor-κB p65 at 2, 4, and 8 hours after the return of spontaneous circulation. Ulinastatin increased the number of living neurons and decreased TUNEL-positive neuron numbers in the cortex at 72 h after the return of spontaneous circulation.

CONCLUSIONS

Ulinastatin preserved neuronal survival and inhibited neuron apoptosis after the return of spontaneous circulation in Wistar rats via attenuation of the oxidative stress response and translocation of nuclear factor-κB p65 in the cortex. In addition, Ulinastatin decreased the production of TNF-α, IL-6, Myeloperoxidase, and Malondialdehyde.

Perioperative ischaemia-induced liver injury and protection strategies: An expanding horizon for anaesthesiologists

Liver resection is an effective modality of treatment in patients with primary liver tumour, metastases from colorectal cancers and selected benign hepatic diseases. Its aim is to resect the grossly visible tumour with clear margins and to ensure that the remnant liver mass has sufficient function which is adequate for survival. With the advent of better preoperative imaging, surgical techniques and perioperative management, there is an improvement in the outcome with decreased mortality. This decline in postoperative mortality after hepatic resection has encouraged surgeons for more radical liver resections, leaving behind smaller liver remnants in a bid to achieve curative surgeries. But despite advances in diagnostic, imaging and surgical techniques, postoperative liver dysfunction of varied severity including death due to liver failure is still a serious problem in such patients. Different surgical and non-surgical techniques like reducing perioperative blood loss and consequent decreased transfusions, vascular occlusion techniques (intermittent portal triad clamping and ischaemic preconditioning), administration of pharmacological agents (dextrose, intraoperative use of methylprednisolone, trimetazidine, ulinastatin and lignocaine) and inhaled anaesthetic agents (sevoflurane) and opioids (remifentanil) have demonstrated the potential benefit and minimised the adverse effects of surgery. In this article, the authors reviewed the surgical and non-surgical measures that could be adopted to minimise the risk of postoperative liver failure following liver surgeries with special emphasis on ischaemic and pharmacological preconditioning which can be easily adapted clinically.

Hepatic ischemia and reperfusion injury and trauma: current concepts

Context

Ischemia-reperfusion injury is a fascinating topic which has drawn a lot of interest in the last several years. Hepatic ischemia reperfusion injury may occur in a variety of clinical situations. These include transplantation, liver resection, trauma, and vascular surgery.

Evidence Acquisition

The purpose of this review was to outline the molecular mechanisms underlying hepatic I/R injury and present the latest approaches, both surgical and pharmacological, regarding the prevention of it. A comprehensive electronic literature search in MEDLINE/PubMed was performed to identify relative articles published within the last 2 years.

Results

The basic mechanism of hepatic ischemia – reperfusion injury is one of blood deprivation during ischemia, followed by the return of flow during reperfusion. It involves a complex series of events, such as mitochondrial deenergization, adenosine-5'-triphosphate depletion, alterations of electrolyte homeostasis, as well as Kupffer cell activation, oxidative stress changes and upregulation of proinflammatory cytokine signaling. The great number of variable pathways, with several mediators interacting with each other, leads to a high number of candidates for potential therapeutic intervention. As far as surgical approaches are concerned, the modification of existing clamping techniques and the ischemic preconditioning are the most promising techniques till recently. In the search for novel techniques of protecting against hepatic ischemia reperfusion injury, many different strategies have been used in experimental models. The biggest part of this research lies around antioxidant therapy, but other potential solutions have been explored as well.

Conclusions

The management of hepatic trauma, in spite of the fact that it has become increasingly nonoperative, there still remains the possibility of hepatic resection in the hepatic trauma setting, especially in severe injuries. Hence, clinicians should be familiar with the concept of hepatic ischemia-reperfusion injury and respond appropriately and timely.