David A. Geller

The nuclear factor HMGB1 mediates hepatic injury after murine liver ischemia-reperfusion

High-mobility group box 1 (HMGB1) is a nuclear factor that is released extracellularly as a late mediator of lethality in sepsis as well as after necrotic, but not apoptotic, death. Here we demonstrate that in contrast to the delayed role of HMGB1 in the systemic inflammation of sepsis, HMGB1 acts as an early mediator of inflammation and organ damage in hepatic ischemia reperfusion (I/R) injury. HMGB1 levels were increased during liver I/R as early as 1 h after reperfusion and then increased in a time-dependent manner up to 24 h. Inhibition of HMGB1 activity with neutralizing antibody significantly decreased liver damage after I/R, whereas administration of recombinant HMGB1 worsened I/R injury. Treatment with neutralizing antibody was associated with less phosphorylation of c-Jun NH2-terminal kinase and higher nuclear factor–κB DNA binding in the liver after I/R. Toll-like receptor 4 (TLR4)-defective (C3H/Hej) mice exhibited less damage in the hepatic I/R model than did wild-type (C3H/HeOuj) mice. Anti-HMGB1 antibody failed to provide protection in C3H/Hej mice, but successfully reduced damage in C3H/Ouj mice. Together, these results demonstrate that HMGB1 is an early mediator of injury and inflammation in liver I/R and implicates TLR4 as one of the receptors that is involved in the process.

The International Position on Laparoscopic Liver Surgery: The Louisville Statement, 2008

Objective:To summarize the current world position on laparoscopic liver surgery. Summary Background Data:Multiple series have reported on the safety and efficacy of laparoscopic liver surgery. Small and medium sized procedures have become commonplace in many centers, while major laparoscopic liver resections have been performed with efficacy and safety equaling open surgery in highly specialized centers. Although the field has begun to expand rapidly, no consensus meeting has been convened to discuss the evolving field of laparoscopic liver surgery. Methods:On November 7 to 8, 2008, 45 experts in hepatobiliary surgery were invited to participate in a consensus conference convened in Louisville, KY, US. In addition, over 300 attendees were present from 5 continents. The conference was divided into sessions, with 2 moderators assigned to each, so as to stimulate discussion and highlight controversies. The format of the meeting varied from formal presentation of experiential data to expert opinion debates. Written and video records of the presentations were produced. Specific areas of discussion included indications for surgery, patient selection, surgical techniques, complications, patient safety, and surgeon training. Results:The consensus conference used the terms pure laparoscopy, hand-assisted laparoscopy, and the hybrid technique to define laparoscopic liver procedures. Currently acceptable indications for laparoscopic liver resection are patients with solitary lesions, 5 cm or less, located in liver segments 2 to 6. The laparoscopic approach to left lateral sectionectomy should be considered standard practice. Although all types of liver resection can be performed laparoscopically, major liver resections (eg, right or left hepatectomies) should be reserved for experienced surgeons facile with more advanced laparoscopic hepatic resections. Conversion should be performed for difficult resections requiring extended operating times, and for patient safety, and should be considered prudent surgical practice rather than failure. In emergent situations, efforts should be made to control bleeding before converting to a formal open approach. Utilization of a hand assist or hybrid technique may be faster, safer, and more efficacious. Indications for surgery for benign hepatic lesions should not be widened simply because the surgery can be done laparoscopically. Although data presented on colorectal metastases did not reveal an adverse effect of the laparoscopic approach on oncological outcomes in terms of margins or survival, adequacy of margins and ability to detect occult lesions are concerns. The pure laparoscopic technique of left lateral sectionectomy was used for adult to child donation while the hybrid approach has been the only one reported to date in the case of adult to adult right lobe donation. Laparoscopic liver surgery has not been tested by controlled trials for efficacy or safety. A prospective randomized trial appears to be logistically prohibitive; however, an international registry should be initiated to document the role and safety of laparoscopic liver resection. Conclusions:Laparoscopic liver surgery is a safe and effective approach to the management of surgical liver disease in the hands of trained surgeons with experience in hepatobiliary and laparoscopic surgery. National and international societies, as well as governing boards, should become involved in the goal of establishing training standards and credentialing, to ensure consistent standards and clinical outcomes.

World review of laparoscopic liver resection-2,804 patients.

Objective:To provide a review of the world literature on laparoscopic liver resection. Summary Background Data:Initially described for peripheral, benign tumors resected by nonanatomic wedge resections, minimally invasive liver resections are now being performed more frequently, even for larger, malignant tumors located in challenging locations. Although a few small review articles have been reported, a comprehensive review on laparoscopic liver resection has not been published. Methods:We conducted a literature search using Pubmed, screening all English publications on laparoscopic liver resections. All data were analyzed and apparent case duplications in updated series were excluded from the total number of patients. Tumor type, operative characteristics, perioperative morbidity, and oncologic outcomes were tabulated. Results:A total of 127 published articles of original series on laparoscopic liver resection were identified, and accounted for 2,804 reported minimally invasive liver resections. Fifty percent were for malignant tumors, 45% were for benign lesions, 1.7% were for live donor hepatectomies, and the rest were indeterminate. Of the resections, 75% were performed totally laparoscopically, 17% were hand-assisted, and 2% were laparoscopic-assisted open hepatic resection (hybrid) technique, with the remainder being other techniques or conversions to open hepatectomies. The most common laparoscopic liver resection was a wedge resection or segmentectomy (45%) followed by anatomic left lateral sectionectomy (20%), right hepatectomy (9%), and left hepatectomy (7%). Conversion from laparoscopy to open laparotomy and from laparoscopy to hand-assisted approach occurred in 4.1% and 0.7% of reported cases, respectively. Overall mortality was 9 of 2,804 patients (0.3%), and morbidity was 10.5%, with no intraoperative deaths reported. The most common cause of postoperative death was liver failure. Postoperative bile leak was observed in 1.5% of cases. For cancer resections, negative surgical margins were achieved in 82% to 100% of reported series. The 5-year overall and disease-free survival rates after laparoscopic liver resection for hepatocellular carcinoma were 50% to 75% and 31% to 38.2%, respectively. The 3-year overall and disease-free survival rates after laparoscopic liver resection for colorectal metastasis to the liver were 80% to 87% and 51%, respectively. Conclusion:In experienced hands, laparoscopic liver resections are safe with acceptable morbidity and mortality for both minor and major hepatic resections. Oncologically, 3- and 5-year survival rates reported for hepatocellular carcinoma and colorectal cancer metastases are comparable to open hepatic resection, albeit in a selected group of patients.

HMGB1 release induced by liver ischemia involves Toll-like receptor 4–dependent reactive oxygen species production and calcium-mediated signaling

Ischemic tissues require mechanisms to alert the immune system of impending cell damage. The nuclear protein high-mobility group box 1 (HMGB1) can activate inflammatory pathways when released from ischemic cells. We elucidate the mechanism by which HMGB1, one of the key alarm molecules released during liver ischemia/reperfusion (I/R), is mobilized in response to hypoxia. HMGB1 release from cultured hepatocytes was found to be an active process regulated by reactive oxygen species (ROS). Optimal production of ROS and subsequent HMGB1 release by hypoxic hepatocytes required intact Toll-like receptor (TLR) 4 signaling. To elucidate the downstream signaling pathways involved in hypoxia-induced HMGB1 release from hepatocytes, we examined the role of calcium signaling in this process. HMGB1 release induced by oxidative stress was markedly reduced by inhibition of calcium/calmodulin-dependent kinases (CaMKs), a family of proteins involved in a wide range of calcium-linked signaling events. In addition, CaMK inhibition substantially decreased liver damage after I/R and resulted in accumulation of HMGB1 in the cytoplasm of hepatocytes. Collectively, these results demonstrate that hypoxia-induced HMGB1 release by hepatocytes is an active, regulated process that occurs through a mechanism promoted by TLR4-dependent ROS production and downstream CaMK-mediated signaling.

Long-term survival after liver transplantation in 4,000 consecutive patients at a single center

ObjectiveTo evaluate the long-term survival outcomes of a large cohort of liver transplant recipients and to identify static and changing factors that influenced these outcomes over time. Summary Background DataLiver transplantation has been accepted as a therapeutic option for patients with end-stage liver disease since 1983, with continual improvements in patient survival as a result of advances in immunosuppression and medical management, technical achievements, and improvements in procurement and preservation. Although many reports, including registry data, have delineated short-term factors that influence survival, few reports have examined factors that affect long-term survival after liver transplantation. MethodsFour thousand consecutive patients who underwent liver transplantation between February 1981 and April 1998 were included in this analysis and were followed up to March 2000. The effect of donor and recipient age at the time of transplantation, recipient gender, diagnosis, and year of transplantation were compared. Rates of retransplantation, causes of retransplantation, and cause of death were also examined. ResultsThe overall patient survival for the entire cohort was 59%; the actuarial 18-year survival was 48%. Patient survival was significantly better in children, in female recipients, and in patients who received transplants after 1990. The rates of retransplantation for acute or chronic rejection were significantly lower with tacrolimus-based immunosuppression. The risk of graft failure and death was relatively stable after the first year, with recurrence of disease, malignancies, and age-related complications being the major factors for loss. ConclusionSignificantly improved patient and graft survival has been observed over time, and graft loss from acute or chronic rejection has emerged as a rarity. Age-related and disease-related causes of graft loss represent the greatest threat to long-term survival.

Multiple NF-κB Enhancer Elements Regulate Cytokine Induction of the Human Inducible Nitric Oxide Synthase Gene

The human inducible nitric oxide synthase (iNOS) gene is overexpressed in a number of human inflammatory diseases. Previously, we observed that the human iNOS gene is transcriptionally regulated by cytokines and demonstrated that the cytokine-responsive regions are upstream of −3.8 kilobase pairs (kb). Therefore, the purpose of this study was to further localize the functional enhancer elements and to assess the role of the transcription factor NF-κB in both human liver (AKN-1) and human lung (A549) epithelial cell lines. The addition of NF-κB inhibitors significantly suppressed cytokine-stimulated iNOS mRNA expression and NO synthesis, indicating that NF-κB is involved in the induction of the human iNOS gene. Analysis of the first 4.7 kb of the 5′-flanking region demonstrated basal promoter activity and failed to show any cytokine-inducible activity. However, promoter constructs extending to −5.8 and −7.2 kb revealed 2–3-fold and 4–5-fold induction, respectively, in the presence of cytokines. DNA sequence analysis from −3.8 to −7.2 kb identified five putative NF-κB cis-regulatory transcription factor binding sites upstream of −4.7 kb. Site-directed mutagenesis of these sites revealed that the NF-κB motif at −5.8 kb is required for cytokine-induced promoter activity, while the sites at −5.2, −5.5, and −6.1 kb elicit a cooperative effect. Electromobility shift assays using a site-specific oligonucleotide and nuclear extracts from cells stimulated with cytokine-mixture, tumor necrosis factor-α or interleukin-1β, but not interferon-γ, exhibited inducible DNA binding activity for NF-κB. These data indicate that NF-κB activation is required for cytokine induction of the human iNOS gene and identifies four NF-κB enhancer elements upstream in the human iNOS promoter that confer inducibility to tumor necrosis factor-α and interleukin-1β.

Recommendations for laparoscopic liver resection: a report from the second international consensus conference held in Morioka.

OBJECTIVE This review aims to assess the impact of implementing dedicated emergency surgical services, in particular acute care surgery, on clinical outcomes. BACKGROUND The optimal model for delivering high-quality emergency surgical care remains unknown. Acute Care Surgery (ACS) is a health care model combining emergency general surgery, trauma, and critical care. It has been adopted across the United States in the management of surgical emergencies. METHOD A systematic review was performed after PRISMA recommendations using the MEDLINE, Embase, and Psych-Info databases. Studies assessing different care models and institutional factors affecting the delivery of emergency general surgery were included. RESULTS Twenty-seven studies comprising 744,238 patients were included in this review. In studies comparing ACS with traditional practice, mortality and morbidity were improved. Moreover, time to senior review, delays to operating theater, and financial expenditure were often reduced. The elements of ACS models varied but included senior clinicians present onsite during office hours and dedicated to emergency care while on-call. Referrals were made to specialist centers with primary surgical assessments taking place on surgical admissions units rather than in the emergency department. Twenty-four-hour access to dedicated emergency operating rooms was also described. CONCLUSIONS ACS models as well as centralized units and hospitals with dedicated emergency operating rooms, access to radiology and intensive care facilities (ITU) are all factors associated with improved clinical and financial outcomes in the delivery of emergency general surgery. There is, however, no consensus on the elements that constitute an ideal ACS model and how it can be implemented into current surgical practice.

Hepatic Resection for Metastatic Colorectal Adenocarcinoma: A Proposal of a Prognostic Scoring System

BACKGROUND Hepatic resection for metastatic colorectal cancer provides excellent longterm results in a substantial proportion of patients. Although various prognostic risk factors have been identified, there has been no dependable staging or prognostic scoring system for metastatic hepatic tumors. STUDY DESIGN Various clinical and pathologic risk factors were examined in 305 consecutive patients who underwent primary hepatic resections for metastatic colorectal cancer. Survival rates were estimated by the Cox proportional hazards model using the equation: S(t) = [So(t)]exp(R-Ro), where So(t) is the survival rate of patients with none of the identified risk factors and Ro = 0. RESULTS Preliminary multivariate analysis revealed that independently significant negative prognosticators were: (1) positive surgical margins, (2) extrahepatic tumor involvement including the lymph node(s), (3) tumor number of three or more, (4) bilobar tumors, and (5) time from treatment of the primary tumor to hepatic recurrence of 30 months or less. Because the survival rates of the 62 patients with positive margins or extrahepatic tumor were uniformly very poor, multivariate analysis was repeated in the remaining 243 patients who did not have these lethal risk factors. The reanalysis revealed that independently significant poor prognosticators were: (1) tumor number of three or more, (2) tumor size greater than 8 cm, (3) time to hepatic recurrence of 30 months or less, and (4) bilobar tumors. Risk scores (R) for tumor recurrence of the culled cohort (n = 243) were calculated by summation of coefficients from the multivariate analysis and were divided into five groups: grade 1, no risk factors (R = 0); grade 2, one risk factor (R = 0.3 to 0.7); grade 3, two risk factors (R = 0.7 to 1.1); grade 4, three risk factors (R= 1.2 to 1.6); and grade 5, four risk factors (R > 1.6). Grade 6 consisted of the 62 culled patients with positive margins or extrahepatic tumor. Kaplan-Meier and Cox proportional hazards estimated 5-year survival rates of grade 1 to 6 patients were 48.3% and 48.3%, 36.6% and 33.7%, 19.9% and 17.9%, 11.9% and 6.4%, 0% and 1.1%, and 0% and 0%, respectively (p < 0.0001). CONCLUSIONS The proposed risk-score grading predicted the survival differences extremely well. Estimated survival as determined by the Cox proportional hazards model was similar to that determined by the Kaplan-Meier method. Verification and further improvements of the proposed system are awaited by other centers or international collaborative studies.

Complex regulation of human inducible nitric oxide synthase gene transcription by Stat 1 and NF-κB

The human inducible nitric oxide synthase (hiNOS) gene is expressed in several disease states and is also important in the normal immune response. Previously, we described a cytokine-responsive enhancer between −5.2 and −6.1 kb in the 5′-flanking hiNOS promoter DNA, which contains multiple nuclear factor κβ (NF-κB) elements. Here, we describe the role of the IFN-Jak kinase-Stat (signal transducer and activator of transcription) 1 pathway for regulation of hiNOS gene transcription. In A549 human lung epithelial cells, a combination of cytokines tumor necrosis factor-α, interleukin-1β, and IFN-γ (TNF-α, IL-1β, and IFN-γ) function synergistically for induction of hiNOS transcription. Pharmacological inhibitors of Jak2 kinase inhibit cytokine-induced Stat 1 DNA-binding and hiNOS gene expression. Expression of a dominant-negative mutant Stat 1 inhibits cytokine-induced hiNOS reporter expression. Site-directed mutagenesis of a cis-acting DNA element at −5.8 kb in the hiNOS promoter identifies a bifunctional NF-κB/Stat 1 motif. In contrast, gel shift assays indicate that only Stat 1 binds to the DNA element at −5.2 kb in the hiNOS promoter. Interestingly, Stat 1 is repressive to basal and stimulated iNOS mRNA expression in 2fTGH human fibroblasts, which are refractory to iNOS induction. Overexpression of NF-κB activates hiNOS promoter–reporter expression in Stat 1 mutant fibroblasts, but not in the wild type, suggesting that Stat 1 inhibits NF-κB function in these cells. These results indicate that both Stat 1 and NF-κB are important in the regulation of hiNOS transcription by cytokines in a complex and cell type-specific manner.

Molecular biology of nitric oxide synthases

Nitric oxide (NO) is a potent biologic mediator with diverse physiologic and pathophysiologic roles. NO is produced from L-arginine by the family of nitric oxide synthase (NOS) enzymes, forming the free radical NO and citrulline as byproduct. Three distinct isoforms of the NOS enzyme have been isolated and represent the products of three different genes. Two of the NOS enzymes are continuously present and are termed constitutive NOS (cNOS). One cNOS enzyme was identified in neurons, and the other in endothelial cells. The two cNOS enzymes are contrasted with the third NOS isoform, inducible NOS, which is not typically expressed in resting cells and must first be induced by certain cytokines, microbial products, or lipopolysaccharide. Since NO production has both beneficial and detrimental consequences, understanding the molecular mechanisms that regulate NOS expression is critical to the control of NO release in homeostatic and pathophysiologic conditions. The purpose of this review is to describe the molecular biology of NO synthases, with particular emphasis on the regulation of the human NO synthase genes. Transcriptional and post-transcriptional regulation of neuronal and endothelial cNOS genes will be reviewed first, followed by the molecular regulation of the inducible NOS gene.