Marc Bilodeau

Variability in hepatic iron concentration measurement from needle-biopsy specimens

BACKGROUND/AIM Quantitative measurement of hepatic iron by biochemical analysis of liver biopsy samples is required to assess hepatic iron stores accurately. Cirrhotic livers, however, contain variable amounts of fibrous tissue and the distribution of iron within the hepatic parenchyma is not always uniform. The aim of this study was to assess the variability in hepatic iron concentration measurement from needle-biopsy specimens. METHODS The livers from eight patients with cirrhosis selected because of elevated serum ferritin were obtained at the time of liver transplantation (n = 6) or at autopsy (n = 2). Multiple needle biopsies were done, and hepatic iron concentration was measured by atomic absorption spectroscopy. The hepatic iron index was calculated as iron concentration divided by age. RESULTS Four cases had a mean hepatic iron index above 2.0, in the range of that reported in patients with homozygous genetic hemochromatosis, whereas the other four had an hepatic iron index of less than 2.0. The intra-individual coefficient of variation for hepatic iron concentration ranged from 11.3 to 43.7%, averaging 24.9%. The coefficient of variation was smaller in biopsy samples > 4 mg dry weight than in samples < 4 mg (19.8% vs 28.6%, p < 0.05). Histological examination of surgical biopsies from these livers showed large amounts of fibrous tissue, and inhomogeneous distribution or iron in the hepatic parenchyma. CONCLUSIONS This study demonstrates an important variability in the measurement of hepatic iron content from needle biopsy specimens in patients with severe cirrhosis.

Historical epidemiology of hepatitis C virus (HCV) in selected countries

Chronic infection with hepatitis C virus (HCV) is a leading indicator for liver disease. New treatment options are becoming available, and there is a need to characterize the epidemiology and disease burden of HCV. Data for prevalence, viremia, genotype, diagnosis and treatment were obtained through literature searches and expert consensus for 16 countries. For some countries, data from centralized registries were used to estimate diagnosis and treatment rates. Data for the number of liver transplants and the proportion attributable to HCV were obtained from centralized databases. Viremic prevalence estimates varied widely between countries, ranging from 0.3% in Austria, England and Germany to 8.5% in Egypt. The largest viremic populations were in Egypt, with 6 358 000 cases in 2008 and Brazil with 2 106 000 cases in 2007. The age distribution of cases differed between countries. In most countries, prevalence rates were higher among males, reflecting higher rates of injection drug use. Diagnosis, treatment and transplant levels also differed considerably between countries. Reliable estimates characterizing HCV‐infected populations are critical for addressing HCV‐related morbidity and mortality. There is a need to quantify the burden of chronic HCV infection at the national level.

Strategies to manage hepatitis C virus (HCV) disease burden

The number of hepatitis C virus (HCV) infections is projected to decline while those with advanced liver disease will increase. A modeling approach was used to forecast two treatment scenarios: (i) the impact of increased treatment efficacy while keeping the number of treated patients constant and (ii) increasing efficacy and treatment rate. This analysis suggests that successful diagnosis and treatment of a small proportion of patients can contribute significantly to the reduction of disease burden in the countries studied. The largest reduction in HCV‐related morbidity and mortality occurs when increased treatment is combined with higher efficacy therapies, generally in combination with increased diagnosis. With a treatment rate of approximately 10%, this analysis suggests it is possible to achieve elimination of HCV (defined as a >90% decline in total infections by 2030). However, for most countries presented, this will require a 3–5 fold increase in diagnosis and/or treatment. Thus, building the public health and clinical provider capacity for improved diagnosis and treatment will be critical.

Sinusoidal endothelial cell and hepatocyte death following cold ischemia‐warm reperfusion of the rat liver

Cold ischemia‐warm reperfusion (CI‐WR) injury of the liver is characterized by marked alterations of sinusoidal endothelial cells (SECs), whereas hepatocytes appear to be relatively unscathed. However, the time course and mechanism of cell death remain controversial: early versus late phenomenon, necrosis versus apoptosis? We describe the occurrence and nature of cell death after different periods of CI with University of Wisconsin (UW) solution and after different periods of WR in the isolated perfused rat liver model. After 24‐ and 42‐hour CI (viable and nonviable livers, respectively), similar patterns of liver cell death were seen: SEC necrosis appeared early after WR (10 minutes) and remained stable for up to 120 minutes. After 30 minutes of WR, apoptosis increased progressively with WR length. Based on morphological criteria, apoptotic cells were mainly hepatocytes within liver plates or extruded in the sinusoidal lumen. In addition, only after 42‐hour CI were large clusters of necrotic hepatocytes found in areas of congested sinusoids. In these same livers, the hepatic microcirculation, evaluated by means of the multiple‐indicator dilution technique, revealed extracellular matrix disappearance with no‐flow areas. In conclusion, different time courses and mechanisms of cell death occur in rat livers after CI‐WR, with early SEC necrosis followed by delayed hepatocyte apoptosis. These processes do not appear to be of major importance in the mechanism of graft failure because they are similar under both nonlethal and lethal conditions; this is not the case for the loss of the extracellular matrix found only under lethal conditions and associated with hepatocyte necrosis. (HEPATOLOGY 2004;39:1110–1119.)

An Update on the Management of Chronic Hepatitis C: 2015 Consensus Guidelines from the Canadian Association for the Study of the Liver

Chronic hepatitis C remains a significant medical and economic burden in Canada, affecting nearly 1% of the population. Since the last Canadian consensus conference on the management of chronic hepatitis C, major advances have occurred that warrant a review of recommended management approaches for these patients. Specifically, direct-acting antiviral agents with dramatically improved rates of virological clearance compared with standard therapy have been developed and interferon-free, all-oral antiviral regimens have been approved. In light of this new evidence, an update to the 2012 Canadian Association for the Study of the Liver consensus guidelines on the management of hepatitis C was produced. The present document reviews the epidemiology of hepatitis C in Canada, preferred diagnostic testing approaches and recommendations for the treatment of chronically infected patients with the newly approved antiviral agents, including those who have previously failed peginterferon and ribavirin-based therapy. In addition, recommendations are made regarding approaches to reducing the burden of hepatitis C in Canada.

Treatment of chronic bleeding from gastric antral vascular ectasia (GAVE) with estrogen-progesterone in cirrhotic patients: an open pilot study.

Objective:Gastric antral vascular ectasia (GAVE) is a rare cause of chronic bleeding in cirrhotic patients. Treatment of GAVE with surgical or nonsurgical portal decompression, β-blockers, or endoscopic therapy provides disappointing results. In the present study, we evaluated the efficacy of estrogen-progesterone therapy, which has been reported to control chronic bleeding in gastrointestinal vascular malformations, such as Osler-Weber Rendu disease or angiodysplasia, in GAVE-related chronic bleeding.Methods:Six cirrhotic patients who bled chronically from GAVE were included. Three had alcoholic cirrhosis, two cryptogenic cirrhosis, and one primary biliary cirrhosis. Grade 1 esophageal varices were noted in four patients. Bleeding could not be controlled by β-blockers, and endoscopic therapy was not considered given the extension of the antral vascular lesions.Results:Before the start of therapy, transfusion requirements averaged 3.5 units/month over a 1.5–11 month period of observation. Patients were then treated with a combination of ethynil estradiol 30 μg and noretisterone 1.5 mg daily. During follow-up (range 3–12 months), bleeding did not recur in four patients; in one patient, treatment with estrogen progesterone decreased the need for transfusions from 4 units/month to 1.4 unit/month; this patient stopped the treatment inadvertently after 6 months and severe anemia recurred with a need for 4 units of blood in the following month; reintroduction of the treatment resulted in an increase of hemoglobin levels without the need for blood transfusions during the following 4 months. In the last patient, a 5-month treatment did not improve chronic bleeding.Conclusion:The present study suggests that estrogen-progesterone therapy is useful in the treatment of chronic bleeding related to GAVE; however, these findings require confirmation by a controlled trial.

Hepatic artery buffer response following left portal vein ligation: its role in liver tissue homeostasis

Occlusion of a lobar portal vein is known to induce atrophy of downstream liver lobes and hypertrophy of contralateral lobes. Changes in portal flow are known to be compensated by changes in hepatic arterial flow, thus defining the hepatic artery buffer response (HABR). To understand the role of liver flow in liver atrophy, we measured portal flow and hepatic artery flow after different degrees of left portal vein stenosis (LPVS). Surgery was performed to obtain 0, 43, 48, 59, 68, 72, 78, and 100% LPVS. Systemic and splanchnic blood flows were measured at 4 h or 7 days after surgery using radiolabeled microspheres. At 4 h, LPVS produced no changes in systemic hemodynamics. Increasing degrees of LPVS produced a significant decrease in left portal flow (P < 0.0001) and a fully compensatory increase in right portal flow (P < 0.0001) without significantly affecting total portal flow. Left hepatic artery flow increased by 210% (P = 0.002), and right hepatic artery flow decreased by 67% (P = 0.05) after full LPVS. There was a significant inverse correlation between portal and arterial flow changes induced by different degrees of LPVS in the left (r(2) = 0. 61) and right (r(2) = 0.41) lobes. Despite this HABR, we observed a reduction in left liver flow (-45%; P = 0.01) and an increase in right liver flow (+230%; P = 0.01) with 100% LPVS. At 7 days, a significant decrease in the weight of left liver lobes (-75%; P < 0. 0001) and a compensatory increase in the weight of the right lobes (+210%; P < 0.0001) were observed with 100% LPVS. Left and right liver flows were similar to results measured at 4 h, and HABR was still present. However, when expressed per gram of liver, liver flows were identical to results obtained with sham animals. Reduction in lobar portal flow is accompanied by an increase in ipsilateral hepatic artery flow and a compensatory increase in portal flow to the rest of the liver. In a given lobe, when compensatory HABR is overcome, liver weight changes occur so that at the end total liver flow per gram of liver tissue is restored. This suggests that in normal conditions liver flow is a major regulator of liver volume.Occlusion of a lobar portal vein is known to induce atrophy of downstream liver lobes and hypertrophy of contralateral lobes. Changes in portal flow are known to be compensated by changes in hepatic arterial flow, thus defining the hepatic artery buffer response (HABR). To understand the role of liver flow in liver atrophy, we measured portal flow and hepatic artery flow after different degrees of left portal vein stenosis (LPVS). Surgery was performed to obtain 0, 43, 48, 59, 68, 72, 78, and 100% LPVS. Systemic and splanchnic blood flows were measured at 4 h or 7 days after surgery using radiolabeled microspheres. At 4 h, LPVS produced no changes in systemic hemodynamics. Increasing degrees of LPVS produced a significant decrease in left portal flow ( P < 0.0001) and a fully compensatory increase in right portal flow ( P < 0.0001) without significantly affecting total portal flow. Left hepatic artery flow increased by 210% ( P = 0.002), and right hepatic artery flow decreased by 67% ( P = 0.05) after full LPVS. There was a significant inverse correlation between portal and arterial flow changes induced by different degrees of LPVS in the left ( r 2 = 0.61) and right ( r 2 = 0.41) lobes. Despite this HABR, we observed a reduction in left liver flow (-45%; P = 0.01) and an increase in right liver flow (+230%; P = 0.01) with 100% LPVS. At 7 days, a significant decrease in the weight of left liver lobes (-75%; P < 0.0001) and a compensatory increase in the weight of the right lobes (+210%; P < 0.0001) were observed with 100% LPVS. Left and right liver flows were similar to results measured at 4 h, and HABR was still present. However, when expressed per gram of liver, liver flows were identical to results obtained with sham animals. Reduction in lobar portal flow is accompanied by an increase in ipsilateral hepatic artery flow and a compensatory increase in portal flow to the rest of the liver. In a given lobe, when compensatory HABR is overcome, liver weight changes occur so that at the end total liver flow per gram of liver tissue is restored. This suggests that in normal conditions liver flow is a major regulator of liver volume.

Burden of disease and cost of chronic hepatitis C virus infection in Canada

BACKGROUND: Chronic infection with hepatitis C virus (HCV) is a major cause of cirrhosis, hepatocellular carcinoma and liver transplantation.

Metabolic insights into the hepatoprotective role of N‐acetylcysteine in mouse liver

The hepatoprotective mechanisms of N‐acetylcysteine (NAC) in non–acetaminophen‐induced liver injury have not been studied in detail. We investigated the possibility that NAC could affect key pathways of hepatocellular metabolism with or without changes in glutathione (GSH) synthesis. Hepatocellular metabolites and high‐energy phosphates were quantified from mouse liver extracts by 1H‐ and 31P‐NMR (nuclear magnetic resonance) spectroscopy. 13C‐NMR‐isotopomer analysis was used to measure [U‐13C]glucose metabolism through pyruvate dehydrogenase (PDH) and pyruvate carboxylase (PC). NAC (150‐1,200 mg/kg) increased liver concentrations of GSH from 8.60 ± 0.48 to a maximum of 12.95 ± 1.03 μmol/g ww, whereas hypotaurine (HTau) concentrations increased from 0.05 ± 0.02 to 9.95 ± 1.12 μmol/g ww. The limited capacity of NAC to increase GSH synthesis was attributed to impaired glucose metabolism through PC. However, 300 mg/kg NAC significantly increased the fractional 13C‐enrichment in Glu (from 2.08% ± 0.26% to 4.00% ± 0.44%) synthesized through PDH, a key enzyme for mitochondrial energy metabolism. This effect could be uncoupled from GSH synthesis and was associated with the prevention of liver injury induced by tert‐butylhydroperoxide and 3‐nitropropionic acid. In conclusion, NAC (1) has a limited capacity to elevate GSH synthesis; (2) increases HTau formation linearly; and (3) improves mitochondrial tricarboxylic acid (TCA) cycle metabolism by stimulation of carbon flux through PDH. This latter effect is independent of the capacity of NAC to replete GSH stores. These metabolic actions, among other yet unknown effects, are critical for NACs therapeutic value and should be taken into account when deciding on a wider use of NAC. (HEPATOLOGY 2006;43:454–463.)

Evaluation of hepatocyte injury following partial ligation of the left portal vein

BACKGROUND/AIMS Total ligation of the left portal vein is thought to induce both hepatocyte apoptosis and necrosis. The pathological impact of partial ligation of a branch of the portal vein has not yet been evaluated. METHODS We studied the degree of hepatocyte injury following 0, 43, 48, 59, 68, 72, 78 and 100% left portal vein stenosis in 200-g Sprague-Dawley male rats. Serum alanine aminotransferase levels, total body weight, and left and right liver lobe weights were measured at 2 and 7 days. Mitosis and 3H-thymidine labelling indices were measured as markers of proliferation; the apoptotic index and TUNEL stain were used as markers to measure apoptotic cell death. Necrosis was assessed morphologically. All these parameters were evaluated 2 days after ligation. RESULTS There was a direct relation between the increase in weight of the right lobes and the reduction in weight of the left lobes. The degree of weight change correlated significantly with the degree of stenosis. In the right lobes, mitosis and 3H-thymidine labelling were increased in proportion to the degree of stenosis. In the left lobes, the decrease in volume of hepatocytes correlated with the degree of ligation, especially in the pericentral areas. Necrosis was identified only when ligation was > or = 68%, this being associated with an increase in alanine aminotransferase levels. On the other hand, apoptotic cells were identified in increasing numbers, starting from the lowest degree of ligation to 100% ligation. This was found both morphologically and with TUNEL stain. CONCLUSIONS Partial ligation of the left portal vein induces left liver atrophy through hepatocyte volume loss and apoptosis. Necrosis is found only when the degree of ligation is severe.