Hyperammonemia is a major etiological toxic factor in the development of hepatic encephalopathy. Brain ammonia detoxification occurs primarily in astrocytes by glutamine synthetase (GS), and it has been proposed that elevated glutamine levels during hyperammonemia lead to astrocyte swelling and cerebral edema. However, ammonia may also be detoxified by the concerted action of glutamate dehydrogenase (GDH) and alanine aminotransferase (ALAT) leading to trapping of ammonia in alanine, which in vivo likely leaves the brain. Our aim was to investigate whether the GS inhibitor methionine sulfoximine (MSO) enhances incorporation of 15NH4+ in alanine during acute hyperammonemia. We observed a fourfold increased amount of 15NH4 incorporation in brain alanine in rats treated with MSO. Furthermore, co-cultures of neurons and astrocytes exposed to 15NH4Cl in the absence or presence of MSO demonstrated a dose-dependent incorporation of 15NH4 into alanine together with increased 15N incorporation in glutamate. These findings provide evidence that ammonia is detoxified by the concerted action of GDH and ALAT both in vivo and in vitro, a mechanism that is accelerated in the presence of MSO thereby reducing the glutamine level in brain. Thus, GS could be a potential drug target in the treatment of hyperammonemia in patients with hepatic encephalopathy.
alanine; hepatic encephalopathy; hyperammonemia; methionine sulfoximine
The prevalence of obesity and related conditions like non-alcoholic fatty liver disease (NAFLD) is increasing worldwide and therapeutic options are limited. Alternative treatment options are therefore intensively sought after. An interesting candidate is the natural polyphenol resveratrol (RSV) that activates adenosinmonophosphate-activated protein kinase (AMPK) and silent information regulation-2 homolog 1 (SIRT1). In addition, RSV has known anti-oxidant and anti-inflammatory effects. Here, we review the current evidence for RSV-mediated effects on NAFLD and address the different aspects of NAFLD and non-alcoholic steatohepatitis (NASH) pathogenesis with respect to free fatty acid (FFA) flux from adipose tissue, hepatic de novo lipogenesis, inadequate FFA β-oxidation and additional intra- and extrahepatic inflammatory and oxidant hits. We review the in vivo evidence from animal studies and clinical trials. The abundance of animal studies reports a decrease in hepatic triglyceride accumulation, liver weight and a general improvement in histological fatty liver changes, along with a reduction in circulating insulin, glucose and lipid levels. Some studies document AMPK or SIRT1 activation, and modulation of relevant markers of hepatic lipogenesis, inflammation and oxidation status. However, AMPK/SIRT1-independent actions are also likely. Clinical trials are scarce and have primarily been performed with a focus on overweight/obese participants without a focus on NAFLD/NASH and histological liver changes. Future clinical studies with appropriate design are needed to clarify the true impact of RSV treatment in NAFLD/NASH patients.
Non-alcoholic fatty liver disease; Non-alcoholic steatohepatitis; Steatosis; Resveratrol; AMP-activated protein kinase; Silent information regulation-2 homolog 1; Anti-oxidants; Anti-inflammatory agents; Animal studies; Clinical trial
In patients with impaired liver function and hepatic encephalopathy (HE), consistent elevations of blood ammonia concentration suggest a crucial role in the pathogenesis of HE. Ammonia and acetate are metabolized in brain both primarily in astrocytes. Here, we used dynamic [11C]acetate PET of the brain to measure the contribution of astrocytes to the previously observed reduction of brain oxidative metabolism in patients with liver cirrhosis and HE, compared to patients with cirrhosis without HE, and to healthy subjects. We used a new kinetic model to estimate uptake from blood to astrocytes and astrocyte metabolism of [11C]acetate. No significant differences of the rate constant of oxidation of [11C]acetate (k3) were found among the three groups of subjects. The net metabolic clearance of [11C]acetate from blood was lower in the group of patients with cirrhosis and HE than in the group of healthy subjects (P < 0.05), which we interpret to be an effect of reduced cerebral blood flow rather than a reflection of low [11C]acetate metabolism. We conclude that the characteristic decline of whole-brain oxidative metabolism in patients with cirrhosis with HE is not due to malfunction of oxidative metabolism in astrocytes. Thus, the observed decline of brain oxidative metabolism implicates changes of neurons and their energy turnover in patients with HE.
astrocytes; brain energy metabolism; kinetic modeling; mitochondria; positron emission tomography
AIM: To evaluate long-term complications and survival in patients with Budd-Chiari syndrome (BCS) referred to a Danish transjugular intrahepatic portosystemic shunt (TIPS) centre.
METHODS: Twenty-one consecutive patients from 1997-2008 were retrospectively included [15 women and 6 men, median age 40 years (range 17-66 years)]. Eighteen Danish patients came from the 1.8 million catchment population of Aarhus University Hospital and three patients were referred from Scandinavian hospitals. Management consisted of tests for underlying haematological, endocrinological, or hypercoagulative disorders parallel to initiation of specific treatment of BCS.
RESULTS: BCS was mainly caused by thrombophilic (33%) or myeloproliferative (19%) disorders. Forty-three percents had symptoms for less than one week with ascites as the most prevalent finding. Fourteen (67%) were treated with TIPS and 7 (33%) were manageable with treatment of the underlying condition and diuretics. The median follow-up time for the TIPS-treated patients was 50 mo (range 15-117 mo), and none required subsequent liver transplantation. Ascites control was achieved in all TIPS patients with a marked reduction in the dose of diuretics. A total of 14 TIPS revisions were needed, mostly of uncovered stents. Two died during follow-up: One non-TIPS patient worsened after 6 mo and died in relation to transplantation, and one TIPS patient died 4 years after the TIPS-procedure, unrelated to BCS.
CONCLUSION: In our BCS cohort TIPS-treated patients have near-complete survival, reduced need for diuretics and compared to historical data a reduced need for liver transplantation.
Ascites; Budd-Chiari syndrome; Myeloproliferative disorder; Thrombophilia; Thrombosis; Transjugular intrahepatic portosystemic shunt
Alcoholic hepatitis (AH) has a severe prognosis due to hepatic inflammatory injury. The cytokine interleukin-22 (IL-22) is reported to exert anti-apoptotic and proliferative effects, but IL-22 has not been studied during the course of AH. IL-22 is mainly produced by CD4+ (helper) T cells, including Th17 cells. In addition, Th17 cells produce the proinflammatory cytokine IL-17A, which has been implicated in AH.
We aimed to study the levels of circulating IL-22- and IL-17A-producing T helper cells and plasma cytokines in patients with AH and to examine the observations in relation to the short-term disease course.
We collected blood samples from 21 consecutive patients with severe AH on days 0, 14 and 30 after diagnosis, and included 10 stable alcoholic cirrhosis patients and 10 healthy subjects as controls. Analyses were performed using flow cytometry and ELISA.
We found higher frequencies of IL-22-producing T helper cells in AH patients (median 1.7%) than in cirrhosis patients (1.0%, p = 0.03) and healthy controls (1.0%, p = 0.01), and a 1.5-fold increase in the plasma concentration of IL-17A in AH compared with healthy controls (p<0.01). Those patients who markedly improved their Glasgow Alcoholic Hepatitis Score demonstrated a 2-fold higher frequency of IL-22-producing T helper cells at baseline and during follow-up than patients whose condition deteriorated (p = 0.04).
The frequency of IL-22-producing T helper cells was increased in AH patients and most so in those whose condition seemed to improve. T cell differentiation toward an IL-22-producing phenotype may thus be favourable in AH.
The cirrhosis complications hepatic encephalopathy, ascites, and variceal bleeding increase mortality but develop in random sequence. Therefore prognoses based on the presence or absence of these clinical complications are inherently inaccurate, and other determinants of the clinical course should be identified. Here we present our study of patho-etiological factors that may be causally involved in the development of specific complications to alcoholic cirrhosis; it was based on a model of cirrhosis pathophysiology encompassing hepatic metabolic capacity, continued alcohol consumption, and circulatory dysfunction.
We followed a Danish community-based cohort of 466 patients with alcoholic cirrhosis. Stratified Cox regression was used to examine the effects of GEC (a measure of hepatic metabolic capacity), alcohol consumption, and plasma sodium concentration (a measure of circulatory dysfunction) on the hazard rates of first-time hepatic encephalopathy, first-time ascites, first-time variceal bleeding, and mortality. We adjusted for confounding by comorbidity, gender, and age. Data on risk factors and confounders were updated during follow-up.
A low GEC increased the risk of first-time hepatic encephalopathy (hazard ratio [HR] 1.21 per 0.1 mmol/min GEC loss, 95% CI 1.11-1.31), but was unassociated with other adverse events. Alcohol consumption increased the risk of first-time ascites (HR 3.18, 95% CI 1.19-8.47), first-time variceal bleeding (HR 2.78, 95% CI 1.59-4.87), and mortality (HR 2.45, 95% CI 1.63-3.66), but not the risk of first-time hepatic encephalopathy. Hyponatremia increased the risk of all adverse events.
Reduced hepatic metabolic capacity, alcohol consumption, and hyponatremia were causally involved in the development of specific complications to alcoholic cirrhosis.
Alcoholic liver disease; Hepatic encephalopathy; Ascites; Variceal bleeding; Prognosis
AIM: To examine the vitamin D status in patients with alcoholic cirrhosis compared to those with primary biliary cirrhosis.
METHODS: Our retrospective case series comprised 89 patients with alcoholic cirrhosis and 34 patients with primary biliary cirrhosis who visited our outpatient clinic in 2005 and underwent a serum vitamin D status assessment.
RESULTS: Among the patients with alcoholic cirrhosis, 85% had serum vitamin D levels below 50 nmol/L and 55% had levels below 25 nmol/L, as compared to 60% and 16% of the patients with primary biliary cirrhosis, respectively (P < 0.001). In both groups, serum vitamin D levels decreased with increasing liver disease severity, as determined by the Child-Pugh score.
CONCLUSION: Vitamin D deficiency in cirrhosis relates to liver dysfunction rather than aetiology, with lower levels of vitamin D in alcoholic cirrhosis than in primary biliary cirrhosis.
Alcoholic liver cirrhosis; Child-Pugh score; Primary biliary cirrhosis; Vitamin D deficiency
Galactose elimination capacity (GEC) is used as a quantitative measure of liver metabolic function with prognostic value in adults with acute and chronic liver failure. Almost no data are available regarding GEC in children, however. This study thus aims to meet the previously unmet clinical need for age-related data on GEC in children.
Material and methods
We studied galactose elimination in 10 healthy children (median age 10.7 years; range 7 months to 16 years) and 30 children with chronic liver disease (median age 8.6 years; range 3 months to 16 years). GEC was estimated from the linear decrease in concentration of galactose in arterialized capillary blood from the ear following intravenous infusion of galactose.
In both groups of children, GEC (µmol/min/kg body weight) was highest in the youngest children and decreased with age, although at a significantly lower level in the children with liver disease (p = 0.05). GEC was significantly higher in healthy children than in healthy adults, diminishing to the adult level by the age of 16 years.
GEC was found to be higher in children than in adults until the age of 16 years. Moreover, GEC was significantly lower in children with chronic liver disease than in healthy children, underlining that GEC testing also has potential clinical usefulness as a quantitative measure of liver metabolic function in children.
Children; galactose; liver disease; liver failure; liver function test
AIM: To study complement activation in 46 patients with alcoholic cirrhosis and ascites but no spontaneous bacterial peritonitis (SBP) and 10 healthy controls.
METHODS: Complement activation was determined by the measurement of soluble membrane attack complex (sMAC) concentrations in ascites and plasma. In patients, metabolic liver function was determined by the galactose elimination capacity and the clinical status assessed by the Model of End-Stage Liver Disease and Child-Pugh scores.
RESULTS: Ascites sMAC levels were markedly higher than in the corresponding plasma sample (median (range): 596 (170 - 1519) vs 160 (77 - 848) μg/L; P < 0.01). Ascites sMAC levels correlated positively with liver status. There was no relationship between ascites sMAC and leukocyte count. No relationship between ascites sMAC and blood C-reactive protein, albumin or neutrophile count was found. Plasma sMAC concentrations were slightly higher in patients than in controls [130 μg/L (70 - 204); P = 0.04]. Neither sMAC in ascites nor plasma was related to mortality.
CONCLUSION: The increased sMAC concentration in ascites and plasma indicate an activation of the complement system in cirrhosis even in the absence of SBP. This was particularly evident in the peritoneal fluid and most marked in patients with preserved liver status. The high ascites sMAC levels may reflect transudation of membrane attack complexes from the liver. Whether this complement activation has any clinical implications remains to be clarified.
Ascites; Cirrhosis; Complement; sC5b-9; Soluble membrane attack complex
AIM: To investigate the effect of transjugular intrahepatic porto-systemic shunt (TIPS) on malnutrition in portal hypertensive cirrhotic patients.
METHODS: Twenty-one patients with liver cirrhosis and clinical indications for TIPS insertion were investigated before and 1, 4, 12, 52 wk after TIPS. For each patient we assayed body composition parameters [dry lean mass, fat mass, total body water (TBW)], routine liver and kidney function tests, and free fatty acids (FFA). Glucose and insulin were measured for the calculation of the homeostasis model assessment insulin resistance (HOMA-IR); liver function was measured by the galactose elimination capacity (GEC); the severity of liver disease was graded by model for end-stage liver disease (MELD).
RESULTS: Porto-systemic gradient decreased after TIPS (6.0 ± 2.1 mmHg vs 15.8 ± 4.8 mmHg, P < 0.001). Patients were divided in two groups according to initial body mass index. After TIPS, normal weight patients had an increase in dry lean mass (from 10.9 ± 5.9 kg to 12.7 ± 5.6 kg, P = 0.031) and TBW (from 34.5 ± 7.6 L to 40.2 ± 10.8 L, P = 0.007), as well as insulin (from 88.9 ± 49.2 pmol/L to 164.7 ± 107.0 pmol/L, P = 0.009) and HOMA-IR (from 3.36% ± 2.18% to 6.18% ± 4.82%, P = 0.023). In overweight patients only FFA increased significantly (from 0.59 ± 0.24 mmol/L to 0.93 ± 0.34 mmol/L, P = 0.023).
CONCLUSION: TIPS procedure is effective in lowering portal pressure in patients with portal hypertension and improves body composition without significant changes in metabolic parameters.
Insulin resistance; Liver cirrhosis; Malnutrition; Portal hypertension; Transjugular intrahepatic porto-systemic shunt
Despite its biologic plausibility, the association between liver function and mortality of patients with chronic liver disease is not well supported by data. Therefore, we examined whether the galactose elimination capacity (GEC), a physiological measure of the total metabolic capacity of the liver, was associated with mortality in a large cohort of patients with newly-diagnosed cirrhosis.
By combining data from a GEC database with data from healthcare registries we identified cirrhosis patients with a GEC test at the time of cirrhosis diagnosis in 1992–2005. We divided the patients into 10 equal-sized groups according to GEC and calculated all-cause mortality as well as cirrhosis-related and not cirrhosis-related mortality for each group. Cox regression was used to adjust the association between GEC and all-cause mortality for confounding by age, gender and comorbidity, measured by the Charlson comorbidity index.
We included 781 patients, and 454 (58%) of them died during 2,617 years of follow-up. Among the 75% of patients with a decreased GEC (<1.75 mmol/min), GEC was a strong predictor of 30-day, 1-year, and 5-year mortality, and this could not be explained by confounding (crude hazard ratio for a 0.5 mmol/min GEC increase = 0.74, 95% CI 0.59–0.92; adjusted hazard ratio = 0.64, 95% CI 0.51–0.81). Further analyses showed that the association between GEC and mortality was identical for patients with alcoholic or non-alcoholic cirrhosis etiology, that it also existed among patients with comorbidity, and that GEC was only a predictor of cirrhosis-related mortality. Among the 25% of patients with a GEC in the normal range (≥ 1.75 mmol/min), GEC was only weakly associated with mortality (crude hazard ratio = 0.79, 95% CI 0.59–1.05; adjusted hazard ratio = 0.80, 95% CI 0.60–1.08).
Among patients with newly-diagnosed cirrhosis and a decreased GEC, the GEC was a strong predictor of short- and long-term all-cause and cirrhosis-related mortality. These findings support the expectation that loss of liver function increases mortality.
Low socioeconomic status is a risk factor for liver cirrhosis, but it is unknown whether it is a prognostic factor after cirrhosis diagnosis. We examined whether marital status, employment, and personal income were associated with the survival of cirrhosis patients.
Using registry-data we conducted a population-based cohort study of 1,765 Danish cirrhosis patients diagnosed in 1999–2001 at age 45–59 years. Follow-up ended on 31 December 2003. With Cox regression we examined the associations between marital status (never married, divorced, married), employment (employed, disability pensioner, unemployed), personal income (0–49, 50–99, 100+ percent of the national average) and survival, controlling for gender, age, cirrhosis severity, comorbidity, and substance abuse.
Five-year survival was higher for married patients (48%) than for patients who never married (40%) or were divorced (34%), but after adjustment only divorced patients had poorer survival than married patients (adjusted hazard ratio for divorced vs. married = 1.22, 95% CI 1.04–1.42). Five-year survival was lower for disability pensioners (31%) than for employed (46%) or unemployed patients (48%), also after adjustment (adjusted hazard ratio for disability pensioners vs. employed = 1.35, 95% CI 1.09–1.66). Personal income was not associated with survival.
Marital status and employment were associated with the survival of cirrhosis patients. Specifically, divorced cirrhosis patients and cirrhosis patients who never married had a poorer survival than did married cirrhosis patients, and cirrhosis patients who were disability pensioners had a poorer survival than did employed or unemployed cirrhosis patients. The poorer survival for the divorced and for the disability pensioners could not be explained by differences in other socioeconomic factors, gender, age, cirrhosis severity, substance abuse, or comorbidity. Personal income was not associated with survival.
Liver diseases are suspected risk factors for intracerebral haemorrhage (ICH). We conducted a population-based case-control study to examine risk of ICH among hospitalised patients with liver cirrhosis and other liver diseases.
We used data from the hospital discharge registries (1991–2003) and the Civil Registration System in Denmark, to identify 3,522 cases of first-time hospitalisation for ICH and 35,173 sex- and age-matched population controls. Among cases and controls we identified patients with a discharge diagnosis of liver cirrhosis or other liver diseases before the date of ICH. We computed odds ratios for ICH by conditional logistic regressions, adjusting for a number of confounding factors.
There was an increased risk of ICH for patients with alcoholic liver cirrhosis (adjusted OR = 4.8, 95% CI: 2.7–8.3), non-alcoholic liver cirrhosis (adjusted OR = 7.7, 95% CI: 2.0–28.9) and non-cirrhotic alcoholic liver disease (adjusted OR = 5.4, 95%CI:3.1–9.5) but not for patients with non-cirrhotic non-alcoholic liver diseases (adjusted OR = 0.9, 95%CI:0.5–1.6). The highest risk was found among women with liver cirrhosis (OR = 8.9, 95%CI:2.9–26.7) and for patients younger than 70 years (OR = 6.1, 95%CI:3.4–10.9). There were no sex- or age-related differences in the association between other liver diseases (alcoholic or non-alcoholic) and hospitalisation with ICH.
Patients with liver cirrhosis and non-cirrhotic alcoholic liver disease have a clearly increased risk for ICH.
Denmark has one of the highest alcohol consumption rates in Northern Europe. The overall per capita alcohol consumption has been stable in recent decades, but surveys have indicated that consumption has decreased in the young and increased in the old. However, there is no recent information on the epidemiology of alcoholic cirrhosis. We examined time trends in incidence, prevalence, and hospitalization rates of alcoholic cirrhosis in Denmark between 1988 and 2005.
We used data from a nationwide population-based hospital registry to identify all Danish citizens with a hospital diagnosis of alcoholic cirrhosis. We computed standardized incidence rates, prevalence and hospitalization rates of alcoholic cirrhosis within the Danish population. We also computed the number of hospitalizations per alcoholic cirrhosis patient per year.
From 1988 to 1993, incidence rates for men and women of any age showed no clear trend, and after a 32 percent increase in 1994, rates were stable throughout 2005. In 2001–2005, the incidence rates were 265 and 118 per 1,000,000 per year for men and women, respectively, and the prevalence rates were 1,326 and 701 per 1,000,000. From 1994, incidence, prevalence, and hospitalization rates decreased for men and women younger than 45 years and increased in the older population, although the latter finding might be partly explained by changes in coding practice. Men and women born around 1960 or later had progressively lower age-specific alcoholic cirrhosis incidence rates than the generations before them. From 1996 to 2005, the number of hospitalizations per alcoholic cirrhosis patient per year increased from 1.3 to 1.5 for men and from 1.1 to 1.2 for women.
From 1988 to 2005, alcoholic cirrhosis put an increasing burden on the Danish healthcare system. However, the decreasing incidence rate in the population younger than 45 years from 1994 indicated that men and women born around 1960 or later had progressively lower incidence rates than the generations before them. Therefore, we expect the overall incidence and prevalence rates of alcoholic cirrhosis to decrease in the future.
Portal vein thrombosis (PVT) is increasingly frequently being diagnosed, but systematic descriptions of the natural history and clinical handling of the condition are sparse. The aim of this retrospective study was to describe risk factors, clinical presentation, complications and treatment of portal vein thrombosis in a single-centre.
Sixty-seven patients were identified in the electronic records from 1992 to 2005. All data were obtained from the patient records.
One or more risk factors (e.g. prothrombotic disorder or abdominal inflammation) were present in 87%. Symptoms were abdominalia, splenomegaly, fever, ascites, haematemesis, and weight loss. Abdominalia and fever occurred more frequently in patients with acute PVT. Frequent complications were splenomegaly, oesophageal- and gastric varices with or without bleeding, portal hypertensive gastropathy and ascites. Varices and bleeding were more frequent in patients with chronic PVT. Patients who received anticoagulant therapy more frequently achieved partial/complete recanalization. Patients with varices who were treated endoscopically in combination with β-blockade had regression of the varices. The overall mortality was 13% in one year, and was dependent on underlying causes.
Most patients had a combination of local and systemic risk factors for PVT. We observed that partial/complete recanalization was more frequent in patients treated with anticoagulation therapy, and that regression of varices was more pronounced in patients who where treated with active endoscopy combined with pharmacological treatment.
Sodium retention and ascites are serious clinical problems in cirrhosis. Urodilatin (URO) is a peptide with paracrine effects in decreasing sodium reabsorption in the distal nephron. Our aim was to investigate the renal potency of synthetic URO on urine sodium excretion in cirrhosis patients with sodium retention and ascites.
Seven cirrhosis patients with diuretics-resistant sodium retention received a short-term (90 min) infusion of URO in a single-blind, placebo-controlled cross-over study. In the basal state after rehydration the patients had urine sodium excretion < 50 mmol/24 h.
URO transiently increased urine sodium excretion from 22 ± 16 μmol/min (mean ± SD) to 78 ± 41 μmol/min (P < 0.05) and there was no effect of placebo (29 ± 14 to 44 ± 32). The increase of URO's second messenger after the receptor, cGMP, was normal. URO had no effect on urine flow or on blood pressure. Most of the patients had highly elevated plasma levels of renin, angiotensin II and aldosterone and URO did not change these.
The short-term low-dose URO infusion increased the sodium excretion of the patients. The increase was small but systematic and potentially clinically important for such patients. The small response contrasts the preserved responsiveness of the URO receptors. The markedly activated systemic pressor hormones in cirrhosis evidently antagonized the local tubular effects of URO.
In patients with cirrhosis, infection is frequent and a leading cause of death. This is secondary to various immunologic abnormalities in both the innate and the adaptive immune system. However, it remains unclear whether cirrhosis affects the inflammatory systemic component of the innate immunity, 'the acute phase response', mostly effectuated by the liver itself. We hypothesized that rats with cirrhosis raise a reduced acute phase response induced by lipopolysaccharide (LPS).
We examined the acute phase response induced by intraperitoneal injection of a low dose of LPS, in sham operated control animals and in rats with liver cirrhosis induced by bile duct ligation (BDL). We measured the serum concentrations of the most important acute phase proteins and their liver tissue gene expressions, assessed by mRNA levels. The BDL-model itself increased the serum concentration of α1-acid glycoprotein (α1AGP) and haptoglobin. LPS was lethal to 25% of the cirrhotic animals and to none of the controls. Twenty-four hours after LPS, the serum concentration of α1AGP and haptoglobin, the mRNA level of these acute phase proteins and of α2-macroglobulin and thiostatin rose to the same level in the animals with cirrhosis and in controls.
In rats with experimental cirrhosis LPS caused high mortality. In the survivors, the cirrhotic liver still synthesized acute phase proteins as the normal liver, indicating a normal hepatic contribution to this part of the acute phase response.