Ian D. McGilvray

Intestinal microbiota in patients with nonalcoholic fatty liver disease

Despite evidence that the intestinal microbiota (IM) is involved in the pathogenesis of obesity, the IM composition of patients with nonalcoholic fatty liver disease (NAFLD) has not been well characterized. This prospective, cross‐sectional study was aimed at identifying differences in IM between adults with biopsy‐proven NAFLD (simple steatosis [SS] or nonalcoholic steatohepatitis [NASH]) and living liver donors as healthy controls (HC). Fifty subjects were included: 11 SS, 22 NASH, and 17 HC. One stool sample was collected from each participant. Quantitative real‐time polymerase chain reaction was used to measure total bacterial counts, Bacteroides/Prevotella (herein referred to as Bacteroidetes), Clostridium leptum, C. coccoides, bifidobacteria, Escherichia coli and Archaea in stool. Clinical and laboratory data, food records, and activity logs were collected. Patients with NASH had a lower percentage of Bacteroidetes (Bacteroidetes to total bacteria counts) compared to both SS and HC (P = 0.006) and higher fecal C. coccoides compared to those with SS (P = 0.04). There were no differences in the remaining microorganisms. As body mass index (BMI) and dietary fat intake differed between the groups (P < 0.05), we performed linear regression adjusting for these variables. The difference in C. coccoides was no longer significant after adjusting for BMI and fat intake. However, there continued to be a significant association between the presence of NASH and lower percentage Bacteroidetes even after adjusting for these variables (P = 0.002; 95% confidence interval = −0.06 to −0.02).

Biliary Strictures in 130 Consecutive Right Lobe Living Donor Liver Transplant Recipients: Results of a Western Center

Biliary strictures remain the most challenging aspect of adult right lobe living donor liver transplantation (RLDLT). Between 04/2000 and 10/2005, 130 consecutive RLDLTs were performed in our center and followed prospectively. Median follow‐up was 23 months (range 3–67) and 1‐year graft and patient survival was 85% and 87%, respectively. Overall incidence of biliary leaks (n = 19) or strictures (n = 22) was 32% (41/128) in 33 patients (26%). A duct‐to‐duct (D‐D) or Roux‐en‐Y (R‐Y) anastomosis were performed equally (n = 64 each) with no difference in stricture rate (p = 0.31). The use of ductoplasty increased the number of grafts with a single duct for anastomosis and reduced the biliary complication rate compared to grafts ≥2 ducts (17% vs. 46%; p = 0.02). Independent risk factors for strictures included older donor age and previous history of a bile leak. All strictures were managed nonsurgically initially but four patients ultimately required conversion from D‐D to R‐Y. Ninety‐six percent (123/128) of patients are currently free of any biliary complications. D‐D anastomosis is safe after RLDLT and provides access for future endoscopic therapy in cases of leak or stricture. When presented with multiple bile ducts, ductoplasty should be considered to reduce the potential chance of stricture.

Accuracy of staging as a predictor for recurrence after liver transplantation for hepatocellular carcinoma

Background. Tumor number, size, and macrovascular invasion (MacroVI) are the most widely used predictors of survival after liver transplantation (LT) for hepatocellular carcinoma (HCC). We analyzed all patients undergoing LT for HCC at our center to establish the accuracy of preoperative clinical staging and to determine which patients have a higher probability of being understaged. Methods. In all, 118 patients with confirmed HCC after LT from April 1991 to October 2004 at our institution were reviewed. All patients were monitored with serial imaging every 3 months to ensure their eligibility for LT within Milan criteria. Understaging in the 118 patients was defined as evidence on explant pathology that Milan criteria (TNM stage pT1 or pT2) had been exceeded. Results. Five-year DFS was 78% with a recurrence rate of 15% after a median follow-up after LT of 30 months. On explant pathology, 43% (51/118) of patients exceeded Milan criteria and had a worse DFS (1 year, 95% vs. 87%; 3 year, 87% vs. 64%; P=0.03) compared to those who met LT criteria. Understaging was more likely in patients with imaging characteristics of ≥2 tumor nodules (P=0.005) and tumor growth >0.25 cm/month (P=0.02) and pathologic findings of vascular invasion (P=0.001) and bilobar tumors (P=0.002). Conclusions. Preoperative imaging every 3 months while on the waiting list frequently understages HCC as assessed by explant pathology. Recurrence after LT often occurred in patients that were understaged. Improving the accuracy of clinical staging and inclusion parameters will ensure proper organ allocation and acceptable outcomes after LT.

Cell-Type Specific Gene Expression Signature in Liver Underlies Response to Interferon Therapy in Chronic Hepatitis C Infection

BACKGROUND & AIMS Chronic hepatitis C virus (CHC) infection is treated with interferon/ribavirin, but only a subset of patients respond. Treatment nonresponders have marked pretreatment up-regulation of a subset of interferon stimulated genes (ISGs) in their livers, including ISG15. We here study how the nonresponder gene expression phenotype is influenced by clinical factors and uncover the cellular basis of the phenotype through ISG15 protein expression. METHODS Seventy-eight CHC patients undergoing treatment were classified by clinical (gender, viral genotype, viral load, treatment outcome) and histologic (inflammation, fibrosis) factors and subjected to gene expression profiling on their pretreatment liver biopsies. An analysis of variance model was used to study the influence of individual factors on gene expression. ISG15 immunohistochemistry was performed on a subset of 31 liver biopsy specimens. RESULTS One hundred twenty-three genes were differentially expressed in the 78 CHC livers when compared with 20 normal livers (P < .001; fold change, > or =1.5-fold). Of genes influenced by a single factor, genotype (1 vs 2/3) influenced more genes (17) than any other variable; when treatment outcome was included in the analysis, this became the predominant influence (24 genes), and the effect of genotype was diminished. Treatment response was linked to cell-specific activation patterns: ISG15 protein up-regulation was more pronounced in hepatocytes in treatment nonresponders but in Kuppfer cells in responders. CONCLUSIONS Genotype is a surrogate marker for the nonresponder phenotype. This phenotype manifests as differential gene expression and is driven by activation of different cell types: hepatocytes in treatment nonresponders and macrophages in treatment responders.

ISG15, a ubiquitin-like interferon-stimulated gene, promotes hepatitis C virus production in vitro: implications for chronic infection and response to treatment

Upregulation of interferon (IFN)-stimulated genes (ISGs), including IFN-stimulated gene 15 (ISG15) and other members of the ISG15 pathway, in pre-treatment liver tissue of patients chronically infected with hepatitis C virus (HCV) is associated with subsequent treatment failure (pegylated IFN-alpha/ribavirin). This study assessed the effect of ISG15 on HCV production in vitro. The levels of ISG15 and of its conjugation to target proteins (ISGylation) were increased by plasmid transfection, but ISGylation was inhibited by small interfering RNA directed against the E1 activating enzyme, Ube1L, in Huh7.5 cells. Cells were infected with HCV FL-J6/JFH virus, and HCV RNA and viral titres were determined. Levels of both HCV RNA and virus increased when levels of ISG15 and ISGylation were increased, and decreased when ISGylation was inhibited. The effects of ISGylation on HCV were independent of upstream IFN signalling: IFN-alpha-induced ISG expression was not altered by Ube1L knockdown. Thus, although ISG15 has antiviral activity against most viruses, ISG15 promotes HCV production. HCV might exploit ISG15 as a host immune evasion mechanism, and this may in part explain how increased expression of ISGs, especially ISG15, correlates with subsequent IFN-based treatment failure.

n -acetyl Cysteine Attenuates Acute Lung Injury In The Rat

&NA; The development of the adult respiratory distress syndrome (ARDS) in the critically ill patient is associated with a significant morbidity and mortality. The pulmonary dysfunction in ARDS is largely secondary to neutrophil‐mediated oxidant injury. The purpose of these studies is to examine the effect of the antioxidant N‐acetyl cysteine (NAC) on a rodent model of lung injury. We postulated that NAC might attenuate lung injury following intratracheal challenge with endotoxin (lipopolysaccharide; LPS). Male Sprague‐Dawley rats were administered NAC systemically either before or after intratracheal administration of LPS. Lung injury was assessed by measuring the transpulmonary leakage of 125l‐labeled albumin, pulmonary myeloperoxidase content, bronchoalveolar lavage fluid cell counts, pulmonary lipid peroxidation and histology. NAC administration significantly attenuated the LPS‐induced increases in lung permeability (LPS: .24 ± .08 vs. LPS + NAC: .12 ± .03, p < .05) and reduced the LPS‐dependent increase in lipid peroxidation. However, total and differential bronchoalveolar lavage cell counts and myeloperoxidase content were not affected by NAC pretreatment. Although neutrophil influx was unaffected, neutrophil activation as assessed by surface CD11b expression and chemiluminescence was significantly down‐regulated by NAC. Importantly, NAC administration up to 2 h after endotoxin challenge was still able to significantly ameliorate LPS‐induced lung injury. Our data suggests that the attenuation of acute lung injury by NAC in our rodent model is related to free radical scavenging and inhibition of the neutrophil oxidative burst, rather than by an effect on inflammatory cell migration. These results suggest novel approaches for therapeutic interventions in acute lung injury.

Live donor liver transplantation in high MELD score recipients.

Background:In 2002, the New York State Committee on Quality Improvement in Living Liver Donation prohibited live liver donation for potential recipients with Model for End-stage Liver Disease (MELD) scores greater than 25. Despite the paucity of evidence to support this recommendation, many centers in North America remain reluctant to offer living donor (LD) to patients with moderate to high MELD scores. Methods:We analyzed 271 consecutive adult-to-adult right lobe LD liver transplants performed at our institution between 2002 and 2008 to study the relationship, between recipient MELD scores and the outcome of LD liver transplantation. The recipients were categorized according to their MELD score into a low (Low: <25)and high (Hi: ≥25) MELD group. We compared short-term donor morbidity, graft loss within 30 days, length of hospital stay, biochemical markers of hepatocyte injury and graft function, and 90 day posttransplant complications including infection, rejection, bleeding, and renal failure. Long-term posttransplant outcome was measured by graft and patient survival after 1-, 3-, and 5-years. Results:Donor and recipient characteristics were similar between groups. Donor outcomes were similar in both groups. Peak recipient aspartat aminotransferase, alanine aminotransferase, and length of hospital stay were similar between both groups. The proportional decrease in postoperative INR and creatinine within the first week was greater in the high versus low MELD score group. High MELD score recipients had more frequent postoperative pneumonia (Low: 2.2% vs. Hi: 14%, P = 0.003), while no differences were observed in rates of biliary complications, rejection, renal failure, or overall infections. Recipients with a MELD <25 versus ≥25 had a similar 1-year (Low: 92% vs. Hi: 83%), 3-year (Low: 86% vs. Hi: 80%), and 5-year (Low: 78% vs. Hi: 80%) graft survival after LD liver transplantation (P = 0.51). Conclusion:LD liver transplantation can provide excellent graft function and survival rates in high MELD score recipients. Thus, when deceased donor organs are scare, a high MELD score alone should not be an absolute contraindication to living liver donation.

Living-Donor Right Hepatectomy with or without Inclusion of Middle Hepatic Vein: Comparison of Morbidity and Outcome in 56 Patients

Venous congestion of segments V and VIII is observed frequently in living‐donor right lobe liver transplants without middle hepatic vein (MHV) drainage, and can be a cause of graft dysfunction and failure. Inclusion of the MHV with the graft is controversial, however, because of the perceived potential for increased donor morbidity.

Adult living liver donors have excellent long-term medical outcomes: the University of Toronto liver transplant experience.

Right lobe living donor liver transplantation is an effective treatment for selected individuals with end‐stage liver disease. Although 1 year donor morbidity and mortality have been reported, little is known about outcomes beyond 1 year. Our objective was to analyze the outcomes of the first 202 consecutive donors performed at our center with a minimum follow‐up of 12 months (range 12–96 months). All physical complications were prospectively recorded and categorized according to the modified Clavien classification system. Donors were seen by a dedicated family physician at 2 weeks, 1, 3 and 12 months postoperatively and yearly thereafter. The cohort included 108 males and 94 females (mean age 37.3 ± 11.5 years). Donor survival was 100%. A total of 39.6% of donors experienced a medical complication during the first year after surgery (21 Grade 1, 27 Grade 2, 32 Grade 3). After 1 year, three donors experienced a medical complication (1 Grade 1, 1 Grade 2, 1 Grade 3). All donors returned to predonation employment or studies although four donors (2%) experienced a psychiatric complication. This prospective study suggests that living liver donation can be performed safely without any serious late medical complications and suggests that long‐term follow‐up may contribute to favorable donor outcomes.

Normothermic Acellular Ex Vivo Liver Perfusion Reduces Liver and Bile Duct Injury of Pig Livers Retrieved After Cardiac Death

We compared cold static with acellular normothermic ex vivo liver perfusion (NEVLP) as a novel preservation technique in a pig model of DCD liver injury. DCD livers (60 min warm ischemia) were cold stored for 4 h, or treated with 4 h cold storage plus 8 h NEVLP. First, the livers were reperfused with diluted blood as a model of transplantation. Liver injury was determined by ALT, oxygen extraction, histology, bile content analysis and hepatic artery (HA) angiography. Second, AST levels and bile production were assessed after DCD liver transplantation. Cold stored versus NEVLP grafts had higher ALT levels (350 ± 125 vs. 55 ± 35 U/L; p < 0.0001), decreased oxygen extraction (250 ± 65 mmHg vs. 410 ± 58 mmHg, p < 0.01) and increased hepatocyte necrosis (45% vs. 10%, p = 0.01). Levels of bilirubin, phospholipids and bile salts were fivefold decreased, while LDH was sixfold higher in cold stored versus NEVLP grafts. HA perfusion was decreased (twofold), and bile duct necrosis was increased (100% vs. 5%, p < 0.0001) in cold stored versus NEVLP livers. Following transplantation, mean serum AST level was higher in the cold stored versus NEVLP group (1809 ± 205 U/L vs. 524 ± 187 U/L, p < 0.05), with similar bile production (2.5 ± 1.2 cc/h vs. 2.8 ± 1.4 cc/h; p = 0.2). NEVLP improved HA perfusion and decreased markers of liver duct injury in DCD grafts.