Experimental and clinical evidence for modification of hepatic ischaemia-reperfusion injury by N-acetylcysteine during major liver surgery

Assessment of Amniotic Fluid as a Preservation Solution in Pig Livers Undergoing Machine Perfusion

INTRODUCTION

Ischemia-reperfusion injury in organ transplantation highlights the need for advanced preservation techniques. This study evaluates the effectiveness of amniotic fluid (AF) compared to static cold storage and histidine-tryptophan-ketoglutarate (HTK) solution in preserving pig livers subjected to hypothermic oxygenated machine perfusion (HOMP) and ex vivo normothermic reperfusion.

MATERIALS AND METHODS

Fifteen pig livers underwent warm ischemia for 1 h, followed by preservation under three conditions: cold storage (group 1, n = 3), HOMP with HTK (group 2, n = 3), and HOMP with AF (group 3, n = 3). Perfusion lasted 4 h, followed by 2 h of ex vivo reperfusion. Assessments included hepatic bile production, sphingomyelin levels, reactive oxygen/nitrogen species, antioxidant capacity, tissue oxygen saturation, flow dynamics, blood gas analyses, biochemical markers, and histopathological and immunohistochemical evaluations.

RESULTS

AF-HOMP showed superior blood flow, lower vascular resistance, higher oxygen saturation, and better organ protection than HTK. Blood gas measurements demonstrated stable physiological levels after reperfusion. AF-HOMP improved bile production, sphingomyelin levels, glycogen preservation, and reduced parenchymal necrosis, hepatocyte vacuolization, and sinusoidal obstruction. Immunohistochemical analysis indicated protective effects on bile duct function, apoptosis, endothelial activation, and cell proliferation.

CONCLUSIONS

AF-HOMP outperformed HTK in preserving liver tissue during warm ischemia, HOMP, and reperfusion. AF is a promising, cost-effective, and accessible alternative for liver preservation, potentially expanding donor pools and improving transplantation outcomes. Further research is warranted to explore its broader applications.

N-Acetylcysteine Supplementation Improves Testicular Haemodynamics, Testosterone Levels, Seminal Antioxidant Capacity and Semen Quality in Heat-Stressed Goat Bucks

Heat stress (HS) disrupts testicular homeostasis because of oxidative stress. N-acetylcysteine (NAC) is a thiol compound with antioxidants, anti-inflammatory and anti-apoptotic properties. As a sequel, this research aimed to assess the ameliorative effects of NAC supplementation on the reproductive performance of goat bucks kept under environmental HS. Primarily, Doppler examination as well as semen collection and evaluation were conducted on 12 mature bucks for 2 weeks (W) as pre-heat stress control (W1 and W2) during winter (February 2023). The temperature-humidity index (THI) was 63.4-64.3 (winter season). Then during summer HS conditions (from the beginning of July till the end of August 2023) bucks were assessed before NAC supplementation (W0), afterwards they were arbitrarily assigned into two groups. The control group (CON; n = 6) received the basal diet while the NAC group (n = 6) received the basal diet in addition to oral NAC daily for 7 weeks (W1-W7). The THI was 78.1-81.6 (summer season). Testicular blood flow parameters, serum concentration of nitric oxide (NO) and testosterone were measured. Additionally, total antioxidant capacity (TAC) and malondialdehyde (MDA) content in seminal plasma and semen quality parameters were evaluated. There were marked reductions (p < 0.05) in the resistive index (RI; W1, W4 and W5), pulsatility index (PI; W2 and W4-W7), and systolic/diastolic ratio (S/D; W4-W7) in the NAC group compared to the CON group. Furthermore, testosterone and NO levels were higher (p < 0.01 and p < 0.05, respectively) in the NAC group (W2, W3, W5 and W3-W5, respectively). Seminal plasma TAC increased (p < 0.05) and MDA decreased (p < 0.05) in the NAC group (W2, W4 and W5) compared to the CON group. Moreover, there were marked improvements (p < 0.05) in semen quality parameters (mass motility, total motility, viability and normal morphology) in the NAC group. In conclusion, oral NAC supplementation could be used to enhance the reproductive performance of goat bucks during HS conditions which is supported by remarkable enhancement in testicular haemodynamics, NO, testosterone levels and semen quality parameters.

Surgical management in hepatoblastoma: points to take

Hepatoblastoma is the most common primary malignant paediatric liver tumour and surgery remains the cornerstone of its management. The aim of this article is to present the principles of surgical treatment of hepatoblastoma. All aspects of surgery in hepatoblastoma are discussed, from biopsy, through conventional and laparoscopic liver resections, to extreme resection with adjacent structures, staged hepatectomy and transplantation.

Vitamin D Receptor Regulates Autophagy to Inhibit Apoptosis and Promote Proliferation in Hepatocyte Injury

BACKGROUND

Oxidative stress is an important mechanism in liver ischemia/reperfusion (I/R) injury. Hepatocyte apoptosis and proliferation occur in parallel with liver I/R injury, and the degree of apoptosis and proliferation determines the effects on hepatocytes. Vitamin D receptor (VDR) can lessen liver I/R injury, but previous studies focused mostly on inflammation and immunity.

METHODS

H₂O₂ was used to induce hepatocyte injury. Before treatment with H₂O₂, Hep-3B cells were pretreated with paricalcitol (PC) and siRNA-VDR. Rapamycin and chloroquine were also applied in the study.

RESULTS

The number of apoptotic cells was measured with an annexin V (AV) -fluorescein isothiocyanate apoptosis detection kit. Expression of proteins was measured by western blotting. As compared with the H₂O₂+Hep-3B group, levels of AV/PI, cleaved caspase-3, and p62 were lower, and expression levels of Bcl-2, proliferating cell nuclear antigen, and VDR were higher, in the PC+H₂O₂+Hep-3B group. When the VDR gene was silenced by siRNA-VDR in the siRNA-VDR+H₂O₂+Hep-3B group, expressions of AV/PI, cleaved caspase-3, and p62 were upregulated, and expressions of Bcl-2, proliferating cell nuclear antigen, and VDR were downregulated, as compared with values for the siRNA-NC+H₂O₂+Hep-3B group. Treatment with rapamycin or chloroquine partially reversed the effect of PC and siRNA-VDR on apoptosis and proliferation.

CONCLUSIONS

VDR mediates hepatocyte apoptosis and proliferation through autophagy.

Optimization of a laparoscopic procedure for advanced intrahepatic cholangiocarcinoma based on the concept of "waiting time": a preliminary report

INTRODUCTION

Clinicians increasingly perform laparoscopic surgery for intrahepatic cholangiocarcinoma (ICC). However, this surgery can be difficult in patients with advanced-stage ICC because of the complicated procedures and difficulty in achieving high-quality results. We compared the effects of a three-step optimized procedure with a traditional procedure for patients with advanced-stage ICC.

METHODS

Forty-two patients with advanced-stage ICC who received optimized laparoscopic hemihepatectomy with lymph node dissection (LND, optimized group) and 84 propensity score-matched patients who received traditional laparoscopic hemihepatectomy plus LND (traditional group) were analyzed. Surgical quality, disease-free survival (DFS), and overall survival (OS) were compared.

RESULTS

The optimized group had a lower surgical bleeding score (P = 0.038) and a higher surgeon satisfaction score (P = 0.001). Blood loss during hepatectomy was less in the optimized group (190 vs. 295 mL, P < 0.001). The optimized group had more harvested LNs (12.0 vs. 8.0, P < 0.001) and more positive LNs (8.0 vs. 5.0, P < 0.001), and a similar rate of adequate LND (88.1% vs. 77.4%, P = 0.149). The optimized group had longer median DFS (9.0 vs. 7.0 months, P = 0.018) and median OS (15.0 vs. 13.0 months, P = 0.046). In addition, the optimized group also had a shorter total operation time (P = 0.001), shorter liver resection time (P = 0.001), shorter LND time (P < 0.001), shorter hospital stay (P < 0.001), and lower incidence of total morbidities (14.3% vs. 36.9%, P = 0.009).

CONCLUSIONS

Our optimization of a three-step laparoscopic procedure for advanced ICC was feasible, improved the quality of liver resection and LND, prolonged survival, and led to better intraoperative and postoperative outcomes.

Current evidence on posthepatectomy liver failure: comprehensive review

INTRODUCTION

Despite important advances in many areas of hepatobiliary surgical practice during the past decades, posthepatectomy liver failure (PHLF) still represents an important clinical challenge for the hepatobiliary surgeon. The aim of this review is to present the current body of evidence regarding different aspects of PHLF.

METHODS

A literature review was conducted to identify relevant articles for each topic of PHLF covered in this review. The literature search was performed using Medical Subject Heading terms on PubMed for articles on PHLF in English until May 2022.

RESULTS

Uniform reporting on PHLF is lacking due to the use of various definitions in the literature. There is no consensus on optimal preoperative assessment before major hepatectomy to avoid PHLF, although many try to estimate future liver remnant function. Once PHLF occurs, there is still no effective treatment, except liver transplantation, where the reported experience is limited.

DISCUSSION

Strict adherence to one definition is advised when reporting data on PHLF. The use of the International Study Group of Liver Surgery criteria of PHLF is recommended. There is still no widespread established method for future liver remnant function assessment. Liver transplantation is currently the only effective way to treat severe, intractable PHLF, but for many indications, this treatment is not available in most countries.

Protective effect of platinum nano-antioxidant and nitric oxide against hepatic ischemia-reperfusion injury

Therapeutic interventions of hepatic ischemia-reperfusion injury to attenuate liver dysfunction or multiple organ failure following liver surgery and transplantation remain limited. Here we present an innovative strategy by integrating a platinum nanoantioxidant and inducible nitric oxide synthase into the zeolitic imidazolate framework-8 based hybrid nanoreactor for effective prevention of ischemia-reperfusion injury. We show that platinum nanoantioxidant can scavenge excessive reactive oxygen species at the injury site and meanwhile generate oxygen for subsequent synthesis of nitric oxide under the catalysis of nitric oxide synthase. We find that such cascade reaction successfully achieves dual protection for the liver through reactive oxygen species clearance and nitric oxide regulation, enabling reduction of oxidative stress, inhibition of macrophage activation and neutrophil recruitment, and ensuring suppression of proinflammatory cytokines. The current work establishes a proof of concept of multifunctional nanotherapeutics against ischemia-reperfusion injury, which may provide a promising intervention solution in clinical use.

Shaping of Hepatic Ischemia/Reperfusion Events: The Crucial Role of Mitochondria

Hepatic ischemia reperfusion injury (HIRI) is a major hurdle in many clinical scenarios, including liver resection and transplantation. Various studies and countless surgical events have led to the observation of a strong correlation between HIRI induced by liver transplantation and early allograft-dysfunction development. The detrimental impact of HIRI has driven the pursuit of new ways to alleviate its adverse effects. At the core of HIRI lies mitochondrial dysfunction. Various studies, from both animal models and in clinical settings, have clearly shown that mitochondrial function is severely hampered by HIRI and that its preservation or restoration is a key indicator of successful organ recovery. Several strategies have been thus implemented throughout the years, targeting mitochondrial function. This work briefly discusses some the most utilized approaches, ranging from surgical practices to pharmacological interventions and highlights how novel strategies can be investigated and implemented by intricately discussing the way mitochondrial function is affected by HIRI.

Literature review of the mechanisms of acute kidney injury secondary to acute liver injury

People exposed to liver ischaemia reperfusion (IR) injury often develop acute kidney injury and the combination is associated with significant morbidity and mortality. Molecular mediators released by the liver in response to IR injury are the likely cause of acute kidney injury (AKI) in this setting, but the mediators have not yet been identified. Identifying the mechanism of injury will allow the identification of therapeutic targets which may modulate both liver IR injury and AKI following liver IR injury.

Oral N-acetylcysteine decreases IFN-γ production and ameliorates ischemia-reperfusion injury in steatotic livers

Type 1 Natural Killer T-cells (NKT1 cells) play a critical role in mediating hepatic ischemia-reperfusion injury (IRI). Although hepatic steatosis is a major risk factor for preservation type injury, how NKT cells impact this is understudied. Given NKT1 cell activation by phospholipid ligands recognized presented by CD1d, we hypothesized that NKT1 cells are key modulators of hepatic IRI because of the increased frequency of activating ligands in the setting of hepatic steatosis. We first demonstrate that IRI is exacerbated by a high-fat diet (HFD) in experimental murine models of warm partial ischemia. This is evident in the evaluation of ALT levels and Phasor-Fluorescence Lifetime (Phasor-FLIM) Imaging for glycolytic stress. Polychromatic flow cytometry identified pronounced increases in CD45+CD3+NK1.1+NKT1 cells in HFD fed mice when compared to mice fed a normal diet (ND). This observation is further extended to IRI, measuring ex vivo cytokine expression in the HFD and ND. Much higher interferon-gamma (IFN-γ) expression is noted in the HFD mice after IRI. We further tested our hypothesis by performing a lipidomic analysis of hepatic tissue and compared this to Phasor-FLIM imaging using "long lifetime species", a byproduct of lipid oxidation. There are higher levels of triacylglycerols and phospholipids in HFD mice. Since N-acetylcysteine (NAC) is able to limit hepatic steatosis, we tested how oral NAC supplementation in HFD mice impacted IRI. Interestingly, oral NAC supplementation in HFD mice results in improved hepatic enhancement using contrast-enhanced magnetic resonance imaging (MRI) compared to HFD control mice and normalization of glycolysis demonstrated by Phasor-FLIM imaging. This correlated with improved biochemical serum levels and a decrease in IFN-γ expression at a tissue level and from CD45+CD3+CD1d+ cells. Lipidomic evaluation of tissue in the HFD+NAC mice demonstrated a drastic decrease in triacylglycerol, suggesting downregulation of the PPAR-γ pathway.

Primary Nonfunction of the Liver Allograft

Severe allograft dysfunction, as opposed to the expected immediate function, following liver transplantation is a major complication, and the clinical manifestations of such that lead to either immediate retransplant or death are the catastrophic end of the spectrum. Primary nonfunction (PNF) has declined in incidence over the years, yet the impact on patient and healthcare teams, and the burden on the organ pool in case of the need for retransplant should not be underestimated. There is no universal test to define the diagnosis of PNF, and current criteria are based on various biochemical parameters surrogate of liver function; moreover, a disparity remains within different healthcare systems on selecting candidates eligible for urgent retransplantation. The impact on PNF from traditionally accepted risk factors has changed somewhat, mainly driven by the rising demand for organs, combined with the concerted approach by clinicians on the in-depth understanding of PNF, optimal graft recipient selection, mitigation of the clinical environment in which a marginal graft is reperfused, and postoperative management. Regardless of the mode, available data suggest machine perfusion strategies help reduce the incidence further but do not completely avert the risk of PNF. The mainstay of management relies on identifying severe allograft dysfunction at a very early stage and aggressive management, while excluding other identifiable causes that mimic severe organ dysfunction. This approach may help salvage some grafts by preventing total graft failure and also maintaining a patient in an optimal physiological state if retransplantation is considered the ultimate patient salvage strategy.

The Potential Role of Efficacy and Safety Evaluation of N-Acetylcysteine Administration During Liver Procurement. The NAC-400 Single Center Randomized Controlled Trial

BACKGROUND

N-acetylcysteine infusions have been widely used to reduce ischemia/reperfusion damage to the liver; however, convincing evidence of their benefits is lacking.

OBJECTIVE

To perform the largest randomized controlled trial to compare the impact of N-acetylcysteine infusion during liver procurement on liver transplant outcomes.

METHODS

Single center, randomized trial with patients recruited from La Fe University Hospital, Spain, from February 2012 to January 2016. A total of 214 grafts were transplanted and randomized to the N-acetylcysteine group (n = 113) or to the standard protocol without N-acetylcysteine (n = 101). The primary endpoint was allograft dysfunction (Olthoff criteria). Secondary outcomes included metabolomic biomarkers of oxidative stress levels, interactions between cold ischemia time and alanine aminotransferase level and graft and patient survival (ID no. NCT01866644).

RESULTS

The incidence of primary dysfunction was 34% (31% in the N-acetylcysteine group and 37.4% in the control group [P = 0.38]). N-acetylcysteine administration reduced the alanine aminotransferase level when cold ischemia time was longer than 6 h (P = 0.0125). Oxidative metabolites (glutathione/oxidized glutathione and ophthalmic acid) were similar in both groups (P > 0.05). Graft and patient survival rates at 12 mo and 3 y were similar between groups (P = 0.54 and P = 0.69, respectively).

CONCLUSIONS

N-acetylcysteine administration during liver procurement does not improve early allograft dysfunction according to the Olthoff classification. However, when cold ischemia time is longer than 6 h, N-acetylcysteine improves postoperative ALT levels.

Combating Ischemia-Reperfusion Injury with Micronutrients and Natural Compounds during Solid Organ Transplantation: Data of Clinical Trials and Lessons of Preclinical Findings

Although extended donor criteria grafts bear a higher risk of complications such as graft dysfunction, the exceeding demand requires to extent the pool of potential donors. The risk of complications is highly associated with ischemia-reperfusion injury, a condition characterized by high loads of oxidative stress exceeding antioxidative defense mechanisms. The antioxidative properties, along with other beneficial effects like anti-inflammatory, antiapoptotic or antiarrhythmic effects of several micronutrients and natural compounds, have recently emerged increasing research interest resulting in various preclinical and clinical studies. Preclinical studies reported about ameliorated oxidative stress and inflammatory status, resulting in improved graft survival. Although the majority of clinical studies confirmed these results, reporting about improved recovery and superior organ function, others failed to do so. Yet, only a limited number of micronutrients and natural compounds have been investigated in a (large) clinical trial. Despite some ambiguous clinical results and modest clinical data availability, the vast majority of convincing animal and in vitro data, along with low cost and easy availability, encourage the conductance of future clinical trials. These should implement insights gained from animal data.

The Effect of Perioperative N-acetylcysteine on the Short and Long Term Outcomes in Pediatrics Undergoing Living-Donor Liver Transplantation

BACKGROUND

Ischemia-reperfusion injury during transplantation can cause post-operative graft dysfunction.

OBJECTIVE

To assess the efficacy of N-acetylcysteine in preventing hepatic ischemia-reperfusion injury and post-transplant outcomes.

METHODS

In this retrospective study on pediatrics undergoing living-donor (from one of their parents) liver transplantation, N-acetylcysteine was administered to one group (n=20) after induction in the donors until graft harvest, and in the recipients during implantation, which was maintained for 19 hours. The second group (n=20) did not receive NAC. Early allograft dysfunction was determined in the presence of alanine aminotransferase or aspartate aminotransferase ≥2000 IU/L and bilirubin ≥10 mg/dL within the first 7 days, and an international normalized ratio ≥1.6 on day 7. Data were collected from a retrospectively maintained database.

RESULTS

The incidence of post-reperfusion syndrome was lower in N-acetylcysteine group compared with the other group (5% vs. 30%, p=0.037). Serum creatinine level was significantly (p=0.04) different in the N-acetylcysteine group during the second post-operative week (0.14 vs. 0.15 mg/dL). There was no significant difference in the incidence of early allograft dysfunction (21% vs. 14%, p=0.327), and the survival rate (p=0.409).

CONCLUSION

Peri-operative infusion of N-acetylcysteine in both donor and recipient would effectively prevent post-reperfusion syndrome and renal insufficiency. However, it might not affect the early allograft dysfunction, ICU stay, and mortality. NAC increases the chance of re-operation due to non-surgical bleeding in the first post-operative day.

Benefits of N-acetylcysteine on liver functions in living donor hepatectomy

Background and Aims:

The proportion of patients undergoing living donor liver transplantation is high especially in countries without or with limited cadaver organ sharing programs. The aim of this study was to evaluate the post-hepatectomy effect of using N-Acetylcysteine (NAC) infusion in living donors undergoing donor hepatectomy.

Methods:

In a prospective randomised non-blinded study, 50 healthy donors were enrolled; following hepatectomy patients were randomised into 2 groups: Group NC receiving NAC 150 mg/kg diluted in 100 ml glucose 5% over 40 minutes, followed by NAC 12.5 mg/kg in 500 ml glucose 5% over 4 hours. This was followed by NAC 6.25 mg/kg for 2 post-operative days, Group C (Control group) received ringer acetate infusion at same rate for 2 days. The primary outcome was serum lactate levels. Secondary outcomes were liver function tests, serum creatinine and urine output on intensive care unit (ICU) admission (0 hr.), after 24 hours and 48 hours, length of ICU stay.

Results:

Our study revealed significant reduction in serum lactate in Group NC at 0, 24 and 48 hours compared to C group (P = 0.017, 0.002, 0.014). INR values showed significant reduction after 48 hours in Group NC compared to Group C (P = 0.049). Total Bilirubin, ALT, and Creatinine, urine output and ICU stay showed no statistical difference between the 2 groups.

Conclusion:

The NAC protocol is a safe, cost-effective tool for improvement of post hepatectomy liver function and early stabilisation of the metabolic profile.

The long term effects of intrascrotal low dose and high dose N-acetylcysteine on testis damage in rat model of testicular torsion

BACKGROUND/PURPOSE

During testicular torsion, the testes face oxidative damage owing to ischemia/reperfusion. We studied the long term effects of the intrascrotal administration of N-acetylcysteine (NAC) during detorsion procedure in a rat model of testicular torsion.

METHODS

Twenty-eight rats were divided into 4 groups: (1) Control group: No procedure was done (2): Torsion-detorsion group: Testis torsion applied for 3 h (3): Low Dose Group: After testis torsion-detorsion (for 3 h) 10 mg/kg NAC was given into tunica vaginalis (4): High Dose Group: After testis torsion-detorsion (for 3 h) 100 mg/kg NAC was given into tunica vaginalis. We measured dimensions of the testes and examined pathological findings and Johnsen and Cosantino Scores.

RESULTS

For testes height and volume, high dose NAC group had better results than the torsion-detorsion group (p = 0.019, p = 0.049). Testes weight showed no difference (p = 0.204). Sertoli cell number per tubule in the high dose NAC group was statistically different than the torsion-detorsion group (p = 0.017).

CONCLUSIONS

When NAC was given intrascrotally at a dose of 100 mg/kg, it decreased the loss of testis volume and height, and Sertoli cell number per tubule was similar to the control group. These results suggest that the higher dose intrascrotal NAC administered during detorsion may have a protective effect.

Melatonin treatment of pigs with acute pancreatitis reduces inflammatory reaction of pancreatic tissue and enhances fitness score of pigs: experimental research

Background

Severe acute pancreatitis is associated with high morbidity and mortality. Melatonin is known as the activator of antioxidant enzymes. The main purpose of this study was to evaluate the clinical effect of melatonin treatment in a pig model with induced acute pancreatitis.

Methods

In this study, acute pancreatitis was induced in 38 German domestic pigs (German Hybrid). After induction of acute pancreatitis, 18 animals were treated with melatonin. Intraoperative clinical data, postoperative blood parameters, fitness, and Porcine Well-being (PWB) score, and post-mortal histopathological data were analyzed in both study groups.

Results

The matching procedure created two groups (melatonin group and control group) which were very similar. The fitness and PWB score were postoperative significantly enhanced in the melatonin group as compared to the control group (p = 0.005 and p = 0.003). Additionally, histological analysis revealed that acinar necrosis, fat tissue necrosis, and edema were significantly reduced in the melatonin group as compared to the non-melatonin group (p = 0.025, p = 0.003, and p = 0.028).

Conclusions

Pigs, which were treated with melatonin, were characterized by higher fitness and PWB scores than those of the control group. Moreover, melatonin treatment reduces the acinar necrosis, fat tissue necrosis, and edema of pancreatic tissue. Thus, melatonin might be a useful therapeutic option in severe acute pancreatitis.

N-acetylcysteine protects hepatocytes from hypoxia-related cell injury

AIM OF THE STUDY

Hepatocyte transplantation has been discussed as an alternative to liver transplantation in selected cases of acute and chronic liver failure and metabolic diseases. Immediately after infusion of hepatocytes, hypoxia-related cell injury is inevitable. N-acetylcysteine (NAC) has been suggested to attenuate hypoxic damage. This study's objective was to evaluate NAC's protective effect in a model of hypoxia-related hepatocyte injury.

MATERIAL AND METHODS

HepG2 cells were used as a model for hepatocytes and were cultured under standardized hypoxia or normoxia for 24 hours with or without NAC. Growth kinetics were monitored using trypan blue staining. The activation of apoptotic pathways was measured using quantitative real-time PCR for Bcl-2/Bax and p53. The proportions of vital, apoptotic and necrotic cells were verified by fluorescence activated cell sorting using annexin V-labelling. The expression of hypoxia inducible factor 1 (HIF-1) was measured indirectly using its downstream target vascular endothelial growth factor A (VEGF-A).

RESULTS

After NAC, cell proliferation increased under both hypoxia and normoxia by 528% and 320% (p < 0.05), while VEGF-A expression decreased under normoxia by 67% and 37% (p < 0.05). Compared to cells treated without NAC under hypoxia, the Bcl-2/Bax ratio increased significantly in cells treated with NAC. This finding was confirmed by an increased number of vital cells in FACS analysis.

CONCLUSIONS

NAC protects hepatocytes from hypoxic injury and ultimately activates anti-apoptotic pathways.

Protective Effects of Apoptosis of Kupffer Cells Induced by Zoledronate Liposomes Following Hepatic Ischemia-Reperfusion Injury

Background

The goal of this study was to observe the effect of the apoptosis of Kupffer cells (KCs) selectively induced by zoledronate liposomes following the hepatic ischemia-reperfusion injury (IRI) in the rat liver transplantation model and to explore its mechanisms.

Material/Methods

The rat liver transplantation model was established using the improved Kamada method. Male Sprague Dawley rats were randomly divided into 3 groups: no liver transplantation or drug treatment (Group A); donor rats were injected with 1 mL normal saline through the tail vein for 3 continuous days before transplantation, and the donor liver was preserved in cold for 2 hours (Group B); donor rats were injected with 1 mL zoledronate liposomes (0.001 mg/mL) through the tail vein for 3 continuous days before transplantation, and the donor liver was preserved in cold for 2 hours (Group C). At 24 hours after transplantation, the receiving rats were sacrificed for sampling.

Results

Compared with Group C and Group A, the bile secretion flow was dramatically decreased in Group B, whereas the serum liver function index [alanine aminotransferase (ALT), glutamate aminotransferase (AST), and γ-glutamyl transpeptidase (γ-GT)] was significantly increased (P<0.01), and the pathological injury area was obviously increased. Compared with Group B, the levels of serum interleukin1 (IL-1), tumor necrosis factor-α (TNF-α), and the apoptotic index in Group C were significantly decreased (P<0.05), and Suzuki scores of congestion, vacuolar degeneration, and necrosis were all reduced (P<0.05).

Conclusions

The apoptosis of KCs selectively induced by zoledronate liposomes inhibited the inflammatory cascade reaction induced by KC activation and reduced the release of cytokines and decreased the extent of IRI in the liver transplantation in animal model.

Graft Dysfunction and Management in Liver Transplantation

Graft dysfunction of the liver allograft manifests across a spectrum in both timing posttransplantation and clinical presentation. This can range from mild transient abnormalities of liver tests to acute liver failure potentially leading to graft failure. The causes of graft dysfunction can be divided into those resulting in early and late graft dysfunction. Although nonspecific, liver biochemistry abnormalities are still the mainstay investigation used in monitoring for dysfunction. This article provides a summary of the main causes and management strategies for liver graft dysfunction in the early through late posttransplant stages.

N-Acetylcysteine inhalation improves pulmonary function in patients received liver transplantation

Postoperative pulmonary complications (PPCs) following orthotopic liver transplantation (OLT) are associated with high morbidity and mortality rates. The effect of N-acetylcysteine (NAC) inhalation on the incidence of PPCs and the outcomes of patients undergoing OLT is unknown. This prospective randomized controlled clinical trial was conducted to investigate the effect of NAC inhalation during OLT on PPCs. Sixty patients were randomly assigned to the NAC group (n = 30) or the control group (n = 30) to receive inhaled NAC or sterilized water, respectively, for 30 min before surgery and 3 h after reperfusion. The incidence of early PPCs and outcomes including survival rate were assessed. Biomarkers including tumor necrosis factor (TNF)-α, interleukin (IL)-8, Clara cell secretory protein (CC16), intercellular adhesion molecule (ICAM)-1, and superoxide dismutase (SOD) were measured in exhaled breath condensate (EBC) at T1 (before surgery) and T2 (at the end of operation) as well as in serum at T1, T2, T3 (12 h after operation), and T4 (24 h after operation). A total of 42 patients (20 in the NAC group and 22 in the control group) were enrolled in the final analysis. Atomization inhaled NAC significantly reduced the incidence of PPCs after OLT. The levels of TNF-α, IL-8, CC16, and ICAM-1 in EBC were significantly lower, and SOD activity was higher, at T2 in the NAC group; similar data were found in serum at T2, T3, and T4. In summary, perioperative NAC inhalation may reduce the incidence of PPCs and improve patient outcomes after OLT.

Calcium Signaling in Liver Injury and Regeneration

The liver fulfills central roles in metabolic control and detoxification and, as such, is continuously exposed to a plethora of insults. Importantly, the liver has a unique ability to regenerate and can completely recoup from most acute, non-iterative insults. However, multiple conditions, including viral hepatitis, non-alcoholic fatty liver disease (NAFLD), long-term alcohol abuse and chronic use of certain medications, can cause persistent injury in which the regenerative capacity eventually becomes dysfunctional, resulting in hepatic scaring and cirrhosis. Calcium is a versatile secondary messenger that regulates multiple hepatic functions, including lipid and carbohydrate metabolism, as well as bile secretion and choleresis. Accordingly, dysregulation of calcium signaling is a hallmark of both acute and chronic liver diseases. In addition, recent research implicates calcium transients as essential components of liver regeneration. In this review, we provide a comprehensive overview of the role of calcium signaling in liver health and disease and discuss the importance of calcium in the orchestration of the ensuing regenerative response. Furthermore, we highlight similarities and differences in spatiotemporal calcium regulation between liver insults of different etiologies. Finally, we discuss intracellular calcium control as an emerging therapeutic target for liver injury and summarize recent clinical findings of calcium modulation for the treatment of ischemic-reperfusion injury, cholestasis and NAFLD.

Current evidence for the use of N-acetylcysteine following liver resection

BACKGROUND

N-acetylcysteine (NAC) has many uses in medicine; notable in the management of paracetamol toxicity, acute liver failure and liver surgery. The aim of this review was to critically appraise the published literature for the routine use of NAC in liver resection surgery.

METHODS

An electronic search was performed of EBSCOhost (Medline and CINAHL database), PubMed and the Cochrane Library for the period 1990-2016. MeSH headings: 'acetyl-cysteine', 'liver resection' and 'hepatectomy' were used to identify all relevant articles published in English.

RESULTS

Following the search criteria used, three articles were included. Two of these studies were randomized controlled trials. All the studies collated data on morbidity and mortality. All three studies did not show a significant difference in overall complications rates in patients that underwent hepatic resection that had NAC infusion compared with patients that did not. In one study, NAC administration was associated with a higher frequency of grade A post-hepatectomy liver failure. In another study, a significantly higher incidence of delirium was observed in the NAC group, which led to the trial to be terminated early.

CONCLUSION

The current published data do not support the routine use of NAC following liver resection.

Propofol post-conditioning alleviates hepatic ischaemia reperfusion injury via BRG1-mediated Nrf2/HO-1 transcriptional activation in human and mice

To explore the effects of propofol post-conditioning (PPC) on hepatic ischaemia/reperfusion injury (HIRI) and the potential mechanisms that might be involved in the interaction of Brahma-related gene1(BRG1) and Nuclear-related factor 2(Nrf2). Patients were randomized into PPC(n = 16) and non-PPC(NPC)( n = 21) groups. Propofol(2 mg/kg) was infused within 10 min. of the onset of liver reperfusion during liver transplantation in the PPC group. Liver function tests, as well as Brg1, Nrf2, Heme oxygenase-1(HO-1) and NADPH:quinone oxidoreductase1(NQO1) expression levels were evaluated. CMV-Brg1 mice were designed to investigate the role of Brg1 overexpression during HIRI. Brg1 and Nrf2 siRNA were used to examine the relationship between Brg1 and Nrf2/HO-1 pathways in propofol-mediated effects in a human hepatocyte(L02) hypoxia/reoxygenation(H/R) model. In patients, PPC attenuated both donor liver pathological and function injury, and reducing oxidative stress markers, compared to the NPC group, 24 hrs after surgery. PPC increased liver Brg1, Nrf2, HO-1 and NQO1 expression. In mice, PPC reduced HIRI by decreasing liver oxidative stress and activating Nrf2/HO-1 pathway, accompanied by up-regulation of BRG1 expression. BRG1 overexpression activated Nrf2/HO-1 transcription in CMV-BRG1 mice during HIRI. In vitro, PPC significantly elevated expression of Nrf2, HO-1 and NQO1, resulting in a reduction of cell DCFH-DA and 8-isoprostane levels and decreased lactate dehydrogenase levels, leading to an overall increase in cell viability. Moreover, the protective effects of propofol were partially abrogated in Nrf2-knock-down or BRG1-knock-down hepatocytes. Nrf2-knock-down drastically reduced protein expression of HO-1 and NQO1, while Brg1-knock-down decreased HO-1 expression. Propofol post-conditioning alleviates HIRI through BRG1-mediated Nrf2/HO-1 transcriptional activation.

ROS homeostasis, a key determinant in liver ischemic-preconditioning

Reactive Oxygen Species (ROS) are key mediators of ischemia-reperfusion injury but also required for the induction of the stress response that limits tissue injury and underlies the protection provided by ischemic-preconditioning protocols. Liver steatosis is an important risk factor for liver transplant failure. Liver steatosis is associated with mitochondrial dysfunction and excessive mitochondrial ROS production. Studies aiming at decreasing the sensibility of the steatotic liver to ischemia-reperfusion injury using pre-conditioning protocols, have shown that the steatotic liver has a reduced capacity to respond to these protocols. Recent studies indicate that these effects are related to a reduced capacity of the steatotic liver to respond to elevated ROS levels following reperfusion by inducing a compensatory response. This failure to respond to ROS is associated with reduced levels of antioxidants, mitochondrial damage, hepatocyte cell death, activation of the immune system and induction of pro-fibrotic mediators.

BGP-15 Protects against Oxidative Stress- or Lipopolysaccharide-Induced Mitochondrial Destabilization and Reduces Mitochondrial Production of Reactive Oxygen Species

Reactive oxygen species (ROS) play a critical role in the progression of mitochondria-related diseases. A novel insulin sensitizer drug candidate, BGP-15, has been shown to have protective effects in several oxidative stress-related diseases in animal and human studies. In this study, we investigated whether the protective effects of BGP-15 are predominantly via preserving mitochondrial integrity and reducing mitochondrial ROS production. BGP-15 was found to accumulate in the mitochondria, protect against ROS-induced mitochondrial depolarization and attenuate ROS-induced mitochondrial ROS production in a cell culture model, and also reduced ROS production predominantly at the complex I-III system in isolated mitochondria. At physiologically relevant concentrations, BGP-15 protected against hydrogen peroxide-induced cell death by reducing both apoptosis and necrosis. Additionally, it attenuated bacterial lipopolysaccharide (LPS)-induced collapse of mitochondrial membrane potential and ROS production in LPS-sensitive U-251 glioma cells, suggesting that BGP-15 may have a protective role in inflammatory diseases. However, BGP-15 did not have any antioxidant effects as shown by in vitro chemical and cell culture systems. These data suggest that BGP-15 could be a novel mitochondrial drug candidate for the prevention of ROS-related and inflammatory disease progression.

The protection effects of (1E,6E)-1,7-diphenylhepta-1,6-diene-3,5-dione, a curcumin analogue, against operative liver injury in rats

The relationship between the chemistry characteristic and the hepatoprotective effects of (1E,6E)-1,7-diphenylhepta-1,6-diene-3,5-dione (DDD), a curcumin analogue, in operative liver injury rats was investigated to reveal the mechanism of hepatic protection effects of DDD. DDD (1.2-4.8mmol/kg) was administrated 10min before reperfusion phase in hepatic ischemia-reperfusion injury (IRI) rats. DDD (4.8mmol/kg) administrated 10min before ischemia and N-acetylcysteine (NAC) (4.8mmol/kg) administrated 10min before reperfusion were included for comparative studies. The plasma liver enzyme activities, histopathological indices and markers of lipid peroxide were determined to evaluate the hepatic protection effects. Effects of DDD on succinate dehydrogenase (SDH) activity were also investigated. DDD showed dose-dependent hepatocyte protections when administrated 10min before reperfusion stages in hepatic IRI rats. DDD showed almost equivalent hepatoprotective effects when administrated 10min before ischemia phase demonstrating that DDD acted on the reperfusion stages selectively against the hepatic IRI, instead of ischemia phase. NAC was not effective against hepatic IRI when treated 10min before reperfusion because of the higher pKa of NAC. In additional, DDD had no effect on the SDH both in hepatic IRI rats and in mitochondria. In conclusion, DDD had dose-dependent hepatocyte protections in the reperfusion stages in hepatic IRI rats, while the observed hepatocyte protections of DDD did not involve SDH activities. β-Diketone structures of DDD were crucial for the hepatocyte protections. The abilities of DDD to clear up the unsaturated aldehydes related with the enolate nucleophilicity and the pKa. DDD might be a promising candidate to treat hepatic IRI.

Liver graft preconditioning, preservation and reconditioning

Liver transplantation is the successful treatment of end-stage liver disease; however, the ischaemia-reperfusion injury still jeopardizes early and long-term post-transplant outcomes. In fact, ischaemia-reperfusion is associated with increased morbidity and graft dysfunction, especially when suboptimal donors are utilized. Strategies to reduce the severity of ischaemia-reperfusion can be applied at different steps of the transplantation process: organ procurement, preservation phase or before revascularization. During the donor procedure, preconditioning consists of pre-treating the graft prior to a sustained ischaemia either by a transient period of ischaemia-reperfusion or administration of anti-ischaemic medication, although a multi-pharmacological approach seems more promising. Different preservation solutions were developed to maintain graft viability during static cold storage, achieving substantial results in terms of liver function and survival in good quality organs but not in suboptimal ones. Indeed, preservation solutions do not prevent dysfunction of poor quality organs and are burdened with inadequate preservation of the biliary epithelium. Advantages derived from either hypo- or normothermic machine perfusion are currently investigated in experimental and clinical settings, suggesting a reconditioning effect possibly improving hepatocyte and biliary preservation and resuscitating graft function prior to transplantation. In this review, we highlight acquired knowledge and recent advances in liver graft preconditioning, preservation and reconditioning.

Novel Insights into the PKCβ-dependent Regulation of the Oxidoreductase p66Shc

Dysfunctional mitochondria contribute to the development of many diseases and pathological conditions through the excessive production of reactive oxygen species (ROS), and, where studied, ablation of p66Shc (p66) was beneficial. p66 translocates to the mitochondria and oxidizes cytochrome c to yield H₂O₂, which in turn initiates cell death. PKCβ-mediated phosphorylation of serine 36 in p66 has been implicated as a key regulatory step preceding mitochondrial translocation, ROS production, and cell death, and PKCβ thus may provide a target for therapeutic intervention. We performed a reassessment of PKCβ regulation of the oxidoreductase activity of p66. Although our experiments did not substantiate Ser³⁶ phosphorylation by PKCβ, they instead provided evidence for Ser¹³⁹ and Ser²¹³ as PKCβ phosphorylation sites regulating the pro-oxidant and pro-apoptotic function of p66. Mutation of another predicted PKCβ phosphorylation site also located in the phosphotyrosine binding domain, threonine 206, had no phenotype. Intriguingly, p66 with Thr²⁰⁶ and Ser²¹³ mutated to glutamic acid showed a gain-of-function phenotype with significantly increased ROS production and cell death induction. Taken together, these data argue for a complex mechanism of PKCβ-dependent regulation of p66 activation involving Ser¹³⁹ and a motif surrounding Ser²¹³.

Effect of N-acetylcysteine on liver recovery after resection: A randomized clinical trial

BACKGROUND AND OBJECTIVES

Liver failure following hepatic resection is a multifactorial complication. In experimental studies, infusion of N-acetylcysteine (NAC) can minimize hepatic parenchymal injury.

METHODS

Patients undergoing liver resection were randomized to postoperative care with or without NAC. No blinding was performed. Overall complication rate was the primary outcome; liver failure, length of stay, and mortality were secondary outcomes. Due to safety concerns, a premature multivariate analysis was performed and included within the model randomization to NAC, preoperative ASA, extent of resection, and intraoperative vascular occlusion as factors.

RESULTS

Two hundred and six patients were randomized (110 to conventional therapy; 96 to NAC). No significant differences were noted in overall complications (32.7% and 45.7%, P = 0.06) or hepatic failure (3.6% and 5.4%, P = 0.537) between treatment groups. There was significantly more delirium within the NAC group (2.7% and 9.8%, P < 0.05) that caused early trial termination. In multivariate analysis, only randomization to NAC (OR = 2.21, 95%CI = 1.16-4.19) and extensive resections (OR = 2.28, 95%CI = 1.22-4.29) were predictive of postoperative complications.

CONCLUSIONS

Patients randomized to postoperative NAC received no benefit. There was a trend toward a higher rate of overall complications and a significantly higher rate of delirium in the NAC group. J. Surg. Oncol. 2016;114:446-450. © 2016 Wiley Periodicals, Inc.

The Effect of Intraoperative N-Acetylcysteine on Hepatocellular Injury During Laparoscopic Bariatric Surgery. A Randomised Controlled Trial

BACKGROUND

The combination of pneumoperitoneum and intraoperative retraction of the left lobe of the liver leads to hepatocellular injury during laparoscopic gastric surgery. Fatty livers are more susceptible to ischaemic insults. This trial investigated whether the antioxidant N-acetylcysteine (NAC) reduced liver injury during laparoscopic sleeve gastrectomy (LSG).

METHODS

Patients undergoing LSG were randomised (single blinded) to receive intraoperative NAC infusion or standard anaesthetic treatment. Blood samples were taken before and after surgery (days 0 to 4). Primary endpoints included serum aminotransferases. Secondary measures were C-reactive protein, weight cell count (WCC), cytokines (interleukin 6 and 10) and cytokeratin-18 as markers of apoptosis. Intraoperative liver biopsy samples were assessed using a locally developed injury score.

RESULTS

Twenty patients (14 females, mean age 44.5 (SEM ± 2.9) years, mean BMI 60.8 (SEM ± 2.4) kg/m(2)) were recruited (NAC n = 10, control n = 10). The trial was stopped early after a planned interim analysis. Baseline liver function was similar. The peak rise in liver enzymes was on day 1, but levels were not significantly different between the groups. Rates of complications and length of stay were not significantly different. Secondary outcome measures, including white cell count (WCC), cytokines and cytokeratin (CK)-18 fragments, were not different between groups. Liver injury scores did not differ significantly.

CONCLUSIONS

NAC did not reduce intraoperative liver injury in this small number of patients. The heterogenous nature of the study population, with differences in co-morbidities, body mass index and intraabdominal anatomy, leads to a varied post-operative inflammatory response. Significant hepatocyte injury occurs through both necrosis and apoptosis.

Hepatic ischemia reperfusion injury: A systematic review of literature and the role of current drugs and biomarkers

Hepatic ischemia reperfusion injury (IRI) is not only a pathophysiological process involving the liver, but also a complex systemic process affecting multiple tissues and organs. Hepatic IRI can seriously impair liver function, even producing irreversible damage, which causes a cascade of multiple organ dysfunction. Many factors, including anaerobic metabolism, mitochondrial damage, oxidative stress and secretion of ROS, intracellular Ca(2+) overload, cytokines and chemokines produced by KCs and neutrophils, and NO, are involved in the regulation of hepatic IRI processes. Matrix Metalloproteinases (MMPs) can be an important mediator of early leukocyte recruitment and target in acute and chronic liver injury associated to ischemia. MMPs and neutrophil gelatinase-associated lipocalin (NGAL) could be used as markers of I-R injury severity stages. This review explores the relationship between factors and inflammatory pathways that characterize hepatic IRI, MMPs and current pharmacological approaches to this disease.

Antioxidant, Antiapoptotic and Inflammatory Effects of Interleukin-18 Binding Protein on Kidney Damage Induced by Hepatic Ischemia Reperfusion

OBJECTIVE

Acute kidney injury (AKI) is a serious condition that can be induced by liver transplantation, major hepatic resection or prolonged portal vein occlusion. The AKI can increase the frequency of postoperative complications. In the current study, we aimed to investigate whether interleukin-18 binding protein (IL-18BP) pretreatment has a protective effect against possible kidney injury-mediated liver ischemia-reperfusion (IR) achieved by Pringle maneuver in an experimental rat model.

MATERIALS AND METHODS

A total of 21 Wistar albino rats were included in this study. Animals were equally and randomly separated into 3 groups as follows: Sham (n = 7), IR group (n = 7) and IR + IL-18BP group (n = 7). Serum aspartate transaminase, alanine aminotransaminase and lactate dehydrogenase enzyme activities and serum urea and creatinine levels were determined. Tumor necrosis factor-α, IL-6, IL-1β, interferon gamma, total oxidant status, total antioxidant status and oxidative stress index were measured in kidney tissue homogenate samples. Histopathological examination and immunohistochemical Caspase-3 staining were applied to examine the general morphologic structure and apoptosis.

RESULTS

Renal total oxidant status; oxidative stress index; IL-18 levels; serum aspartate transaminase, alanine aminotransaminase and lactate dehydrogenase activities and creatinine levels were significantly lower in IR + IL-18BP group, when compared with the IR group. Beside this, total antioxidant status levels were remarkably higher in IR + IL-18BP group, when compared with the IR group. The caspase-3 expression degree in IR group was remarkably higher than other groups.

CONCLUSIONS

It has been demonstrated that IL-18BP pretreatment may have inflammatory, antioxidant and antiapoptotic effects against AKI induced by hepatic IR.

Reactions of electrophiles with nucleophilic thiolate sites: relevance to pathophysiological mechanisms and remediation

Electrophiles are electron-deficient species that form covalent bonds with electron-rich nucleophiles. In biological systems, reversible electrophile-nucleophile interactions mediate basal cytophysiological functions (e.g. enzyme regulation through S-nitrosylation), whereas irreversible electrophilic adduction of cellular macromolecules is involved in pathogenic processes that underlie many disease and injury states. The nucleophiles most often targeted by electrophiles are side chains on protein amino acids (e.g. Cys, His, and Lys) and aromatic nitrogen sites on DNA bases (e.g. guanine N7). The sulfhydryl thiol (RSH) side chain of cysteine residues is a weak nucleophile that can be ionized in specific conditions to a more reactive nucleophilic thiolate (RS(-)). This review will focus on electrophile interactions with cysteine thiolates and the pathophysiological consequences that result from irreversible electrophile modification of this anionic sulfur. According to the Hard and Soft, Acids and Bases (HSAB) theory of Pearson, electrophiles and nucleophiles can be classified as either soft or hard depending on their relative polarizability. HSAB theory suggests that electrophiles will preferentially and more rapidly form covalent adducts with nucleophiles of comparable softness or hardness. Application of HSAB principles, in conjunction with in vitro and proteomic studies, have indicated that soft electrophiles of broad chemical classes selectively form covalent Michael-type adducts with soft, highly reactive cysteine thiolate nucleophiles. Therefore, these electrophiles exhibit a common mechanism of cytotoxicity. As we will discuss, this level of detailed mechanistic understanding is a necessary prerequisite for the rational development of effective prevention and treatment strategies for electrophile-based pathogenic states.

Effects of N-Acetylcysteine Addition to University of Wisconsin Solution on the Rate of Ischemia-Reperfusion Injury in Adult Orthotopic Liver Transplant

OBJECTIVES

One of the main concerns in liver transplant is the prolonged ischemia time, which may lead to primary graft nonfunction or delayed function. N-acetylcysteine is known as a hepato-protective agent in different studies, which may improve human hepatocyte viability in steatotic donor livers. This study investigated whether N-acetylcysteine can decrease the rate of ischemia-reperfusion syndrome and improve short-term outcome in liver transplant recipients.

MATERIALS AND METHODS

This was a double-blind, randomized, control clinical trial of 115 patients. Between April 2012 and January 2013, patients with orthotopic liver transplant were randomly divided into 2 groups; in 49 cases N-acetylcysteine was added to University of Wisconsin solution as the preservative liquid (experimental group), and in 66 cases standard University of Wisconsin solution was used (control group). We compared postreperfusion hypotension, inotrope requirement before and after portal reperfusion, intermittent arterial blood gas analysis and potassium measurement, pathological review of transplanted liver, in-hospital complications, morbidity, and mortality.

RESULTS

There was no significant difference between the groups regarding time to hepatic artery reperfusion, hospital stay, vascular complications, inotrope requirement before and after portal declamping, and blood gas analysis. Hypotension after portal reperfusion was significantly more common in experimental group compared with control group (P = .005). Retransplant and in-hospital mortality were comparable between the groups.

CONCLUSIONS

Preservation of the liver inside Univer-sity of Wisconsin solution plus N-acetylcysteine did not change the rate of ischemia reperfusion injury and short-term outcome in liver transplant recipients.

2-Acetylcyclopentanone, an enolate-forming 1,3-dicarbonyl compound, is cytoprotective in warm ischemia-reperfusion injury of rat liver

We have previously shown that 2-acetylcyclopentanone (2-ACP), an enolate-forming 1,3-dicarbonyl compound, provides protection in cell culture and animal models of oxidative stress. The pathophysiology of ischemia-reperfusion injury (IRI) involves oxidative stress, and, therefore, we determined the ability of 2-ACP to prevent this injury in a rat liver model. IRI was induced by clamping the portal vasculature for 45 minutes (ischemia phase), followed by recirculation for 180 minutes (reperfusion phase). This sequence was associated with substantial derangement of plasma liver enzyme activities, histopathological indices, and markers of oxidative stress. The 2-ACP (0.80-2.40 mmol/kg), administered by intraperitoneal injection 10 minutes prior to reperfusion, provided dose-dependent cytoprotection, as indicated by normalization of the IRI-altered liver histologic and biochemical parameters. The 2-ACP (2.40 mmol/kg) was also hepatoprotective when injected before clamping the circulation (ischemia phase). In contrast, an equimolar dose of N-acetylcysteine (2.40 mmol/kg) was not hepatoprotective when administered prior to reperfusion. Our studies to date suggest that during reperfusion the enolate nucleophile of 2-ACP limits the consequences of mitochondrial-based oxidative stress through scavenging unsaturated aldehyde electrophiles (e.g., acrolein) and chelation of metal ions that catalyze the free radical-generating Fenton reaction. The ability of 2-ACP to reduce IRI when injected prior to ischemia most likely reflects the short duration of this experimental phase (45 minutes) and favorable pharmacokinetics that maintain effective 2-ACP liver concentrations during subsequent reperfusion. These results provide evidence that 2-ACP or an analog might be useful in treating IRI and other conditions that have oxidative stress as a common molecular etiology.

Oxidative stress triggers cytokinesis failure in hepatocytes upon isolation

Primary hepatocytes are highly differentiated cells and proliferatively quiescent. However, the stress produced during liver digestion seems to activate cell cycle entry by proliferative/dedifferentiation programs that still remain unclear. The aim of this work was to assess whether the oxidative stress associated with hepatocyte isolation affects cell cycle and particularly cytokinesis, the final step of mitosis. Hepatocytes were isolated from C57BL/6 mice by collagenase perfusion in the absence and presence of N-acetyl cysteine (NAC). Polyploidy, cell cycle, and reactive oxygen species (ROS) were studied by flow cytometry (DNA, phospho-histone 3, and CellROX(®) Deep Red) and Western blotting (cyclins B1 and D1, and proliferating cell nuclear antigen). mRNA expression of cyclins A1, B1, B2, D1, and F by reverse transcription (RT)-PCR was also assessed. Glutathione levels were measured by mass spectrometry. Here we show that hepatocyte isolation enhanced cell cycle entry, increased hepatocyte binucleation, and caused marked glutathione oxidation. Addition of 5 mM NAC to the hepatocyte isolation media prevented glutathione depletion, partially blocked ROS production and cell cycle entry of hepatocytes, and avoided the blockade of mitosis progression, abrogating defective cytokinesis and diminishing the formation of binucleated hepatocytes during isolation. Therefore, addition of NAC to the isolation media decreased the generation of polyploid hepatocytes confirming that oxidative stress occurs during hepatocyte isolation and it is responsible, at least in part, for cytokinesis failure and hepatocyte binucleation.

Protective effects of N-acetylcysteine in concanavalin A-induced hepatitis in mice

This study was designed to study the protective effects and mechanisms of N-acetylcysteine (NAC) in concanavalin A-induced hepatitis in mice. In this study, pretreatment with NAC ameliorated the histopathological changes and suppressed inflammatory cytokines in ConA-induced hepatitis. The expression of IL-2, IL-6, TNF-α, and IFN-γ was significantly reduced in the NAC-treated groups. NAC activated PI3K/Akt pathway and inhibited the activation of NF-κB. Additionally, NAC reduced autophagosome formation, as assessed by detecting the expression of LC3 and Beclin 1. Our results demonstrate that NAC can alleviate ConA-induced hepatitis by regulating the PI3K/Akt pathway and reducing the late stages of autophagy. Our results described a new pharmaceutical to provide more effective therapies for immune hepatitis.

Post hepatectomy liver failure: concept of management

BACKGROUND

In literature, the reported mortality of posthepatectomy liver failure is <5 % and morbidity is 15-30 %. Around 3-8 % of patients develop liver failure after major hepatic resection.

OBJECTIVE

The objective of the study was to provide current definitions and managing posthepatectomy liver failure (PHLF) as per severity and ISGLS grading.

METHOD

A systemic search of pubmed indexed articles was done and relevant articles were selected to formulate latest guidelines for PHLF.

CONCLUSION

We were able to make an algorithm for standardizing management so as to identify and treat PHLF as early as possible.

Use of Pharmacologic Agents for Modulation of Ischaemia-Reperfusion Injury after Hepatectomy: A Questionnaire Study of the LiverMetSurvey International Registry of Hepatic Surgery Units

Objectives. This study is a questionnaire survey on the use of pharmacological agents to modify liver ischaemia-reperfusion (IR) injury in patients undergoing hepatectomy for colorectal liver metastases with the target population being those units participating in the LiverMetSurvey international registry. Methods. Members of LiverMetSurvey were sent an online questionnaire using SurveyMonkey comprising ten questions on the use of pharmacological agents to modulate hepatic IR injury in the perioperative period after hepatectomy. The questionnaire was sent to 446 clinicians registered with the LiverMetSurvey. There were 83 (19%) respondents. Results. Fifty-two (77% of 68 respondents to this question) never used pharmacological agents to modify liver IR injury during hepatectomy. Thirteen (19%) used pharmacological agents selectively. Three (4%) used these routinely. N-Acetylcysteine was the most widely used pharmacological agent with equal distribution of use around intraoperative and postoperative periods. Conclusions. This is believed to be the first survey on the use of pharmacological agents to modify liver IR injury. The target population is clinicians involved in liver resection. The results show that pharmacological modulation is used by only a minority of respondents to this questionnaire and that when this treatment is selected, N-acetylcysteine is the most frequently used.

Nrf2 activation protects the liver from ischemia/reperfusion injury in mice

OBJECTIVE

To investigate the role of Nrf2 in the pathogenesis of hepatic ischemia-reperfusion (I/R) injury.

BACKGROUND

Hepatic I/R injury is a serious complication that leads to liver failure after liver surgery. NF-E2-related factor 2 (Nrf2) is a transcription factor that plays a critical role in protecting cells against oxidative stress. Therefore, it is suggested that Nrf2 activation protects the liver from I/R injury.

METHODS

Wild-type and Nrf2-deficient mice were treated with 15-deoxy-Δ(12,14)-prostaglandin J2 (15d-PGJ2), or a vehicle. Subsequently, these mice were subjected to 60-minute hepatic 70% ischemia, followed by reperfusion. Liver and blood samples were collected to evaluate liver injury and mRNA expressions.

RESULTS

After hepatic I/R, Nrf2-deficient livers exhibited enhanced tissue damage; impaired GSTm1, NQO1, and GCLc inductions; disturbed redox state; and aggravated tumor necrosis factor α mRNA expression in comparison with wild-type livers. 15d-PGJ2 treatment protected the livers of wild-type mice from I/R injury via increased expressions of GSTm1, NQO1, and GCLc; maintained redox status; and decreased tumor necrosis factor α induction. These effects induced by 15d-PGJ2 were not seen in the livers of Nrf2(-/-) mice and were not annulled by peroxisome proliferator-activated receptor γ antagonist in Nrf2(+/+) mice, suggesting that the protective effect of 15d-PGJ2 is mediated by Nrf2-dependent antioxidant response.

CONCLUSIONS

Nrf2 plays a critical role in the mechanism of hepatic I/R injury and would be a new therapeutic target for preventing hepatic I/R injury during liver surgery.

Redox therapeutics in hepatic ischemia reperfusion injury

Ischemia-reperfusion plays a major role in the injury experienced by the liver during transplantation. Much work has been done recently investigating the role of redox species in hepatic ischemia-reperfusion. As animal models are better characterized and developed, and more insights are gained into the pathophysiology of hepatic ischemia reperfusion injury in humans the questions into exactly how oxidants participate in this injury are becoming more refined. These questions include effects of cellular location, timing of injury, and ability of therapeutics to access this site are increasing our appreciation of the complexity of ischemia reperfusion and improving attempts to ameliorate its effects. In this review, we aim to discuss the various methods to alter redox chemistry during ischemia reperfusion injury and future prospects for preventing organ injury during hepatic ischemia reperfusion.

Current knowledge on oxidative stress in hepatic ischemia/reperfusion

Ischemia/reperfusion (I/R) injury associated with hepatic resections and liver transplantation remains a serious complication in clinical practice, despite several attempts to solve the problem. The redox balance, which is pivotal for normal function and integrity of tissues, is dysregulated during I/R, leading to an accumulation of reactive oxygen species (ROS). Formation of ROS and oxidant stress are the disease mechanisms most commonly invoked in hepatic I/R injury. The present review examines published results regarding possible sources of ROS and their effects in the context of I/R injury. We also review the effect of oxidative stress on marginal livers, which are more vulnerable to I/R-induced oxidative stress. Strategies to improve the viability of marginal livers could reduce the risk of dysfunction after surgery and increase the number of organs suitable for transplantation. The review also considers the therapeutic strategies developed in recent years to reduce the oxidative stress induced by hepatic I/R, and we seek to explain why some of them have not been applied clinically. New antioxidant strategies that have yielded promising results for hepatic I/R injury are discussed.

N-acetylcysteine administration does not improve patient outcome after liver resection

BACKGROUND

Post-operative hepatic dysfunction is a major cause of concern when undertaking a liver resection. The generation of reactive oxygen species (ROS) as a result of hepatic ischaemia/reperfusion (I/R) injury can result in hepatocellular injury. Experimental evidence suggests that N-acetylcysteine may ameliorate ROS-mediated liver injury.

METHODS

A cohort of 44 patients who had undergone a liver resection and receiving peri-operative N-acetylcysteine (NAC) were compared with a further cohort of 44 patients who did not. Liver function tests were compared on post-operative days 1, 3 and 5. Peri-operative outcome data were retrieved from a prospectively maintained database within our unit.

RESULTS

Administration of NAC was associated with a prolonged prothrombin time on the third post-operative day (18.4 versus 16.4 s; P = 0.002). The incidence of grades B and C liver failure was lower in the NAC group although this difference did not reach statistical significance (6.9% versus 14%; P = 0.287). The overall complication rate was similar between groups (32% versus 25%; P = ns). There were two peri-operative deaths in the NAC group and one in the control group (P = NS).

CONCLUSION

In spite of promising experimental evidence, this study was not able to demonstrate any advantage in the routine administration of peri-operative NAC in patients undergoing a liver resection.