Cystic Fibrosis-associated Liver Disease Research Articles

Non-invasive liver elastography (Fibroscan) for detection of cystic fibrosis-associated liver disease

Background Cystic fibrosis-associated liver disease (CFLD) is the second cause of mortality in CF. The prevalence is estimated to be 26–45%, but sensitive diagnostic tools are lacking. We investigated whether non-invasive liver elastography (Fibroscan) could serve as a screening tool. Methods Fibroscan measurements were performed in 66 CF patients. Age-specific cutoff values were determined in a control population ( n = 59). The measurements were compared to clinical data, biyearly biochemistry and ultrasound. Results Fibroscan was easy to perform in this patient population. There were 14 patients (21%) with abnormal liver stiffness measurements. Liver stiffness was significantly increased in patients with clinical CFLD (11.2 kPa versus 5.1 kPa), biochemical CFLD (7.4 kPa versus 5.4 kPa) or ultrasonographical CFLD (8.2 versus 4.3 kPa) ( p < 0.02 for all). Conclusions Fibroscan is an objective measure and is easy to perform in CF patients, even in children and could provide a valuable tool to detect, and quantify CFLD.

Immunity in CF associated liver disease

Immunity in CF associated liver disease

MBL serum levels in children with CF-associated liver disease

MBL serum levels in children with CF-associated liver disease

Plasma oxysterols in normal and cholestatic children as indicators of the two pathways of bile acid synthesis

Background No information is available on the hepatic and extrahepatic pathways of bile acid synthesis in normal children and in pediatric cholestatic liver diseases. Methods To explore the changes of the two pathways of bile acid synthesis during development, plasma concentrations of 7α-hydroxycholesterol and 27-hydroxycholesterol were measured in 50 healthy children (1 month–14 years) and compared to 18 adult controls. We also measured plasma oxysterols in 31 patients with pediatric cholestatic liver disease. Results A progressive increase of plasma concentrations of both 27-hydroxycholesterol and 7α-hydroxycholesterol was found with age. In children with cystic fibrosis-associated liver disease plasma concentrations of 27-hydroxycholesterol were significantly lower compared to age-matched controls (5.6 ± 0.5 vs. 12.8 ± 1.1 μg/dl; p < 0.001) and paralleled significantly lower concentrations of total cholesterol. In infants with biliary atresia plasma concentrations of 27-hydroxycholesterol were significantly higher compared to age-matched controls (8.8 ± 0.8 vs. 4.4 ± 0.6 μg/dl, p < 0.001) paralleling significantly higher concentrations of total cholesterol while 7α-hydroxycholesterol resulted significantly lower (1.2 ± 0.2 vs. 2.3 ± 0.3 μg/100 mg of total cholesterol; p = 0.011). Conclusions Our data suggest that both pathways of bile acid synthesis reach a state of maturity only after the age of 4 years and are significantly influenced also in children by liver function and intestinal absorption of cholesterol.

Liver disease in cystic fibrosis

This review highlights recent developments in liver disease associated with cystic fibrosis. The broad spectrum of hepatobiliary problems in cystic fibrosis includes specific alterations ascribable to the underlying defect as well as lesions of iatrogenic origin or that reflect the effects of a disease process occurring outside the liver. Focal biliary cirrhosis, resulting from biliary obstruction and progressive periportal fibrosis, is the most clinically relevant problem, because extension of the initially focal fibrogenic process may lead to multilobular biliary cirrhosis, portal hypertension and eventually liver failure. Cystic fibrosis associated liver disease is presently classified among genetic cholangiopathies and results from lack or dysfunction of the cystic fibrosis transmembrane regulator at the apical membrane of bile duct cells. Major advances have been achieved regarding characterization of natural history, risk factors, diagnostic modalities and treatment options. Liver disease is a relatively frequent and early complication of cystic fibrosis. The pathogenesis is apparently multifactorial, with contributions from environmental and genetic determinants. Its impact on quality of life and survival will increase in future years, and its early detection and treatment will become increasingly important issues. Ursodeoxycholic acid is the only treatment currently available, but novel therapeutic options are being evaluated.

Long-term docosahexaenoic acid therapy in a congenic murine model of cystic fibrosis

We used a congenic C57Bl/6J cystic fibrosis transmembrane conductance regulator (Cftr)(-/-) mouse model, which develops cystic fibrosis (CF)-like pathology in all organs, to evaluate the short- and long-term therapeutic effects of dietary docosahexaenoic acid (DHA). Thirty-day-old Cftr(-/-) mice and wild-type littermates were randomized to receive a liquid diet with or without DHA (40 mg/day). Animals were killed for histological and lipid analysis after 7, 30, and 60 days of therapy. DHA had no significant therapeutic or harmful effect on the lung, pancreas, or ileum of the Cftr(-/-) mice or their wild-type littermates. In contrast, dietary DHA resulted in highly significant amelioration of the severity of liver disease in the Cftr(-/-) mice, primarily a reduction in the degree of peri-portal inflammation. Additionally, these detailed measurements confirm our previous findings that Cftr(-/-) mice have significant alterations in the pancreas (except external acinar diameter), ileum, liver, lung, and salivary (except sublingual) glands at all ages compared with their age-matched wild-type littermates. In conclusion, inhibition of cytokines and/or eicosanoid metabolism and release of endogenous inhibitors of inflammation by DHA may account for the anti-inflammatory effects in the liver of this congenic murine model of CF. The potential therapeutic benefits of DHA in severe CF-associated liver disease remain to be explored.

Liver involvement in cystic fibrosis

The hepatobiliary manifestations of cystic fibrosis (CF) encompass a broad clinical spectrum, from mild steatosis, associated with poor nutrition, to multilobular cirrhosis and the complications of portal hypertension. The factor(s) responsible for the development and progression of liver disease in a subset of patients with CF are unknown. Liver disease can be silent and progressive, manifesting only with complications associated with cirrhosis and portal hypertension. Clinical evaluation for detecting and monitoring the progression of liver disease includes the following: physical examination of the liver, biochemical tests of liver function and injury, and radiological imaging with abdominal ultrasonography. Careful monitoring should take place in all patients with CF, as currently, there are no sensitive and/or specific historical or biochemical markers to predict who is at risk for the development of liver disease. Current treatment options for CF-associated liver disease are very limited. The bile acid ursodeoxycholic acid may improve biochemical parameters of liver disease, but its long-term efficacy in preventing the progression of liver disease in CF is unproven. Treatment therefore rests on optimizing nutritional status; correcting fat-soluble vitamin, essential fatty acid, and other mineral deficiencies; and treating complications of end-stage liver disease, such as pruritus, ascites, and portal hypertension.

Elevated hepatic SULT1E1 activity in mouse models of cystic fibrosis alters the regulation of estrogen responsive proteins

Background Previous studies with cystic fibrosis transmembrane conductance regulator (CFTR) ΔF508 mice indicate that estrogen levels may play a role in the occurrence or severity of CF-associated liver disease. However, the underlying mechanisms of liver disease in CF are poorly understood. Methods The levels of SULT1E1 (estrogen sulfotransferase) were measured in livers of control and CFTR-knockout (KO) mice. The impact of increased SULT1E1 activity on hepatic protein expression was assessed by immunoblot and MALDI mass spectrometric analysis. Results SULT1E1 expression was significantly elevated in livers of several CFTR-KO mice. SULT1E1 and CFTR were specifically detected in hepatocytes and cholangiocytes, respectively. Elevated SULT1E1 activity may result in lower levels of free β-estradiol thereby altering estrogen-responsive hepatic protein expression. Estrogen receptors (ER)-α and β were differentially regulated in CFTR-KO and CFTR-ΔF508 mice. ERα expression was reduced in mice with high SULT1E1 activity. Glutathione S-transferase-P1 and carbonic anhydrase III were significantly decreased in CFTR (−/−) mice with high SULT1E1 activity. Furthermore, cytochrome P450 2B9, also estrogen regulated, was significantly induced in the livers of CFTR (−/−) mice with high SULT1E1 activity. Conclusions Elevated SULT1E1 levels and associated alterations in estrogen-regulated hepatic protein expression may play an important role in CF liver disease.

Symposium summaries

First paragraph:Liver disease is a major complication for patients with cystic fibrosis (CF), where the principal cause of morbidity and mortality is hepatic fibrosis and cirrhosis. Significant morbidity from CF-associated liver disease (CFLD) occurs in up to 17% of children with CF and cirrhosis is detected in up to 10%. Clinically significant fibrosis during life is difficult to determine as no adequate diagnostic test is available and thus diagnosis is frequently not established until serious complications such as portal hypertension are already established. Liver biopsy has for many years been the standard method for diagnosing and quantifying fibrosis, however, it can potentially be confounded by sampling error due to the focal periportal fibrosis and focal biliary cirrhosis which are characteristic of CFLD. While the precise pathobiological mechanisms responsible for liver disease in CF remain to be determined, the activated hepatic stellate cell (HSC) has been demonstrated as the cellular source of increased procollagen a1(I)mRNA expression in CFLD and thus responsible for fibrillar collagen deposition and ensuing hepatic fibrosis and cirrhosis seen in CF. The deposition of excess extracellular matrix including fibrillar collagens in hepatic fibrosis is due to an imbalance between the synthesis and degradation of these matrix components (ie., matrix re-modelling) by HSCs. Measuring the products of HSC fibrogenic activity is one of the more recent innovative approaches for monitoring fibrosis progression in chronic liver disease.

Cystic fibrosis–associated liver disease: a population-based study

Objectives The aim of this study was to explore the clinical factors associated with the development of cystic fibrosis–associated liver disease (CFALD). Study design This was a case-control study of all children (age 5–18 years) with established CFALD in the Republic of Ireland between January 1999 and June 2000. Each child was pair matched for age and sex with a patient with cystic fibrosis (CF) without evidence of liver disease. Only children with clinically overt liver disease were enrolled in the disease group. Results Patients with established CFALD (n = 42; 26 boys) were enrolled. Children with CFALD had worse forced expiratory volume in 1 second values than those without CFALD. However, chest radiography and clinical scores did not differ between groups. Height (mean difference, −4.2 cm [95% confidence interval [CI], −7.41 to −0.90], P = .014), weight (mean difference, −3.21 kg [95% CI, −6.03 to −0.40], P = .026), and mid-upper arm circumference (mean difference, −1.23 cm [95% CI, −2.35 to −0.12], P = .031) were significantly lower among children with CFALD. Children with CFALD were given diagnoses of CF later than children without liver disease. There were more children with meconium ileus in the control group (14 vs 4) than among those with CFALD. Conclusions Children with established CFALD have impaired growth and nutrition, altered body composition, and worse forced expiratory volume in 1 second values. CFALD is associated with later age of diagnosis of CF.

Cystic fibrosis-associated liver disease (CFALD): what is the risk?

As life expectancy for patients with cystic fibrosis (CF) is extended through improved nutritional and pulmonary care, hepatobiliary lesions are recognized more frequently and are being characterized more precisely. Currently, liver disease is the most common nonpulmonary cause of death in patients with CF. Given the increasing prevalence with age, the question arises whether liver disease is an inevitable consequence of CF. The answer is no—this was recognized as early as 1956 by DiSant'Agnese and Blanc who reported that “liver disease has a variable occurrence despite the propensity for most patients to develop inspissated secretions; this suggests additional factors contribute.” So, why does only a subset of patients with CF develop liver disease? A partial explanation relates to the variable and inconsistent definition of “liver disease” in various centers and in the sensitivity of detection. CFALD is not easy to detect; clinical identification of the developing fibrotic liver lesion is difficult due to a lack of symptoms until portal hypertension is obvious. There are also likely to be factors intrinsic to the patient that determine whether liver disease will develop. A recent study found elevated endogenous biliary concentrations of ursodeoxycholic acid (UDCA) in patients with CF but without liver disease compared with those with CFALD. This suggests a possible protective role of UDCA against liver injury (Smith et al. Hepatology 2004;39:1673). What about specific risk factors for CFALD? No mutation in the CF gene is more frequent in patients with CFALD; however, liver disease is confined to patients with severe mutations (those associated with pancreatic insufficiency) (Colombo et al. JPediatr 1994;124:393, and Hepatology 2002;36:1374). These studies also cited male sex, a history of meconium ileus (MI), and certain HLA types as risk factors. In this issue of The Journal, Corbett et al report a case-controlled study of all children with CF in the Republic of Ireland in whom a diagnosis of CFALD was established over an 18-month period. They sought clinical factors associated with the onset of liver disease. Delayed diagnosis seemingly predisposed the development of CFALD, and children with liver disease had early evidence of impaired growth and nutrition, altered body compositions, and worsened pulmonary status. MI was not a risk factor in their patients. These new data add support to the recommendation for enhanced CF screening programs and may add some insight into the risk factors for development of CFALD.

Liver biopsy size matters in chronic hepatitis: Bigger is better

Improved survival of children with CF has increased our need to understand the relevance of cystic fibrosis-associated liver disease (CFLD). We assessed the impact of liver disease and disease severity on the survival of children with cystic fibrosis.A real life, single center cohort study with 27 years follow up was conducted. Mild CFLD was diagnosed as children with abnormal serum liver function tests and abnormal ultrasound. Advanced CFLD was established by detection of cirrhosis or portal hypertension. A directed acyclic graph, Kaplan-Meier (KM) and Cox regression analysis were used to model survival.290 patients were enrolled, 48 (16.5%) had mild CFLD and 55 (19%) had advanced CFLD. Ten children with advanced CFLD and 1 with mild CFLD died. Based on the KM analysis, the mean (SE) overall survival age of all CF children was 29.1 years (0.50). The mean (SE) survival among females with advanced CFLD was 24.7 years (1.58) compared to 30.4 years (0.66) for females without advanced CFLD (p = 0.0027). Advanced CFLD was a predictor of decreased survival when adjusted for sex and diabetes (HR 2.54, 95%CI 1.05–6.15, p = 0.039). Mild CFLD was not associated with decreased survival. The effect of advanced CFLD on survival was mainly borne by females (HR = 6.37, 95%CI 1.62–25.06 vs. males, HR = 1.00, 95%CI 0.25–4.01).Advanced but not mild CFLD was associated with an increased risk of death when adjusted for sex and diabetes, and resulted in premature death in females with cystic fibrosis by approximately 6 years.

Detection of CF-associated liver disease

Detection of CF-associated liver disease

The Role of Hepatic Stellate Cells and Transforming Growth Factor-β 1 in Cystic Fibrosis Liver Disease

Liver disease causes significant morbidity and mortality from multilobular cirrhosis in patients with cystic fibrosis. Abnormal bile transport and biliary fibrosis implicate abnormal biliary physiology in the pathogenesis of cystic fibrosis-associated liver disease (CFLD), yet the mediators linking biliary events to fibrosis remain unknown. Activated hepatic stellate cells (HSCs) are the pre-eminent mediators of fibrosis in a range of hepatic disorders. The dominant stimulus for matrix production by HSCs is the cytokine transforming growth factor (TGF)-beta(1). In CFLD, the role of HSCs and the source of TGF-beta(1) have not been evaluated. Liver biopsy tissue obtained from 38 children with CFLD was analyzed. Activated HSCs, identified by co-localization of procollagen alpha(1)(I) mRNA and alpha-smooth muscle actin, were demonstrated as the cellular source of excess collagen production in the fibrosis surrounding the bile ducts and the advancing edge of scar tissue. TGF-beta protein and TGF-beta(1) mRNA expression were shown to be predominantly expressed by bile duct epithelial cells. TGF-beta(1) expression was significantly correlated with both hepatic fibrosis and the percentage of portal tracts showing histological abnormalities associated with CFLD. This study demonstrates a definitive role for HSCs in fibrogenesis associated with CFLD and establishes a potential mechanism for the induction of HSC collagen gene expression through the production of TGF-beta(1) by bile duct epithelial cells.

Use of ursodeoxycholic acid in patients with liver disease

Ursodeoxycholic acid (UDCA), the 7beta-epimer of chenodeoxycholic acid, has multiple hepatoprotective activities. UDCA modifies the bile acid pool, decreasing levels of endogenous, hydrophobic bile acids while increasing the proportion of nontoxic hydrophilic bile acids. UDCA has a choleretic effect, increasing hepatocellular bile acid excretion, as well as cytoprotective, antiapoptotic, and immunomodulatory properties. UDCA has been shown to delay development of gastroesophageal varices and progression to cirrhosis as well as to improve long-term survival in patients with primary biliary cirrhosis. Significant improvement of abnormal liver tests may be achieved during UDCA therapy in patients with primary sclerosing cholangitis, intrahepatic cholestasis of pregnancy, cystic fibrosis-associated liver disease, nonalcoholic fatty liver disease, graft-versus-host disease of the liver, total parenteral nutrition-induced cholestasis, and in some pediatric cholestatic liver diseases. However, unlike the effects of UDCA in primary biliary cirrhosis, the long-term effects of UDCA in disease progression and survival in these other conditions remain to be established.

Treatment of vitamin K deficiency in cystic fibrosis: Effectiveness of a daily fat-soluble vitamin combination

Objective: Patients with cystic fibrosis (CF) and pancreatic insufficiency (PI) commonly have vitamin K deficiency, and those with CF-associated liver disease (CFLD) have universal vitamin K deficiency. We evaluated the effectiveness of an oral fat-soluble vitamin combination (ADEKs®) to treat patients with vitamin K deficiency. Study design: Patients with PI and CF (mean age, 15 years; range, 0.6 to 46 years) including 6 with advanced CFLD were prospectively enrolled in a study of a fat-soluble vitamin combination taken on a daily basis. None had received vitamin K supplementation for at least 4 months before the study. Fat-soluble vitamin combination supplementation was given for a minimum of 4 months; the mean vitamin K intake was 0.18 mg/d (SD = 0.1, range, 0 to 0.3). The primary outcome was change in plasma PIVKA-II (prothrombin in vitamin K absence). Results: Before supplementation 58 (81%) of 72 patients had abnormal PIVKA-II levels (>2.9 ng/mL). After supplementation 29 (40%) had abnormal PIVKA-II levels (P =.001). All 6 patients with advanced CFLD had abnormal PIVKA-II levels (median, range of 20.8, 5.5 to 55 ng/mL) before treatment, which corrected to normal in 50% (4.1, 2.1 to 65 ng/mL). Four patients, 2 with CFLD, had a prolonged prothrombin time (>13.5 seconds) at both time periods. Conclusions: An oral fat-soluble vitamin combination with a modest amount of vitamin K can, as a daily supplement, improve the PIVKA-II levels in patients with PI and CF. (J Pediatr 2001;138:851-5)

Cholangiocyte biology and cystic fibrosis liver disease.

Cystic fibrosis (CF) is one of the most common inherited diseases in the white population. The disease results from mutations in the gene for the cystic fibrosis transmembrane conductance regulator (CFTR). How this gene defect leads to the clinical manifestations of the disease, however, is not entirely clear. CFTR functions as a Cl(-) channel in the apical membrane of most secretory epithelia, including biliary epithelial cells, or cholangiocytes. In cholangiocytes, CFTR appears to be an important determinant of biliary secretion and bile flow. Additionally, recent evidence suggests that CFTR regulates other membrane transporters, channels, and proteins. Improving life expectancy has led to an increasing recognition of hepatobiliary complications from CF. The true prevalence of CF liver disease is unknown, but may affect up to 17-25% of CF patients. Clinical manifestations include hepatic steatosis, neonatal cholestasis, focal nodular cirrhosis, multilobular cirrhosis, and biliary tract complications. Why only a subset of CF patients develops severe liver disease and others with the same genotype do not is one of the many scientific curiosities of this disease. This review focuses on the function of CFTR in cholangiocytes with emphasis on ductular bile formation as well as the clinical consequences of abnormal CFTR, namely CF-associated liver disease. Data on the pathogenesis, prevalence, clinical course, and treatment of CF liver disease will be reviewed.

Expression of cystic fibrosis transmembrane conductance regulator in liver tissue from patients with cystic fibrosis

The authors examined the expression of cystic fibrosis transmembrane conductance regulator (CFTR) and its relationship to histopathological changes in cystic fibrosis (CF) liver tissue. Immunohistochemistry was used to examine expression of CFTR, intercellular adhesion molecule-1 (ICAM-1) and liver cell-type markers in liver cryosections in 11 patients with CF-associated liver disease, and non-CF controls with (n = 17) and without (n = 3) liver disease. In CF patients prominent inflammatory infiltrates were not found, yet hepatic stellate cells were identified within fibrotic areas around bile ducts. Proliferating bile ducts displayed ICAM-1 immunoreactivity in 3 cases, but bile ducts were otherwise negative. In 2 patients homozygous for R764X and for 1112delT no CFTR immunoreactivity was detected. Bile-duct epithelial cells in patients carrying the ΔF508 mutation displayed aberrant cytoplasmic immunolocalization of CFTR, as determined with confocal laser scanning microscopy, in contrast to the distinct CFTR expression at the luminal surface seen in controls. No clear relationship between CFTR expression and fibrosis or inflammation was evidenced in CF patients. In conclusion, these findings are consistent with an impairment of ΔF508 CFTR processing in intrahepatic biliary epithelium. ICAM-1 expression on bile-duct epithelial cells and inflammatory infiltrates were rare findings in CF liver tissue, indicating that immunological mechanisms are unlikely to be involved in initiation of CF-associated liver disease. (Hepatology 2000;32:334-340.)

Natural history of liver disease in cystic fibrosis.

The median age of the population with cystic fibrosis (CF) has increased worldwide, which has led to the suggestion that the prevalence of liver disease would increase. The aim of this study was to evaluate the natural history of CF-associated liver disease over a 15-year period in a well-controlled population of patients with CF. During the years 1976 through 1993, 124 patients were followed up by yearly liver function tests (LFTs). Fifteen patients were followed up with liver biopsies throughout the whole study period. More than 50% of the patients had pathological LFTs in infancy, later being normalized. Approximately 25% of children 4 years of age or older had biochemical markers of liver disease during the study period. In about 10% of the patients, cirrhosis or advanced fibrosis was confirmed at biopsy and 4% of patients had cirrhosis with clinical liver disease. Severe liver disease developed mainly during prepuberty and puberty. Of the 15 patients prospectively followed up with liver biopsies, only 3 had progressive fibrosis. No specific risk factor was identified, but deficiency of essential fatty acids was found more often in patients with marked steatosis (P <.05). No patient developed clinical liver disease in adulthood and the histological changes in the liver biopsies were usually not progressive. Liver disease was no more frequent at the end of the study period although the median age of the patient population had increased. Modern treatment might positively influence liver disease because it seemed less common, less progressive, and less serious than previously reported.

Delayed intestinal visualization at hepatobiliary scintigraphy is associated with response to long-term treatment with ursodeoxycholic acid in patients with cystic fibrosis-associated liver disease

Background/Aims: Abnormalities of biliary drainage have been documented at hepatobiliary scintigraphy in many but not all patients studied with cystic fibrosisassociated liver disease. Ursodeoxycholic acid was shown to be beneficial in this disease, mainly by improving biliarysecretion. Therefore, patients with impaired biliary drainage are expected to obtain the greatest benefit from this treatment.Methods: We evaluated the effects of long-term treatment with ursodeoxycholic acid in 36 patients with cystic fibrosis-associated liver disease, and compared the response in patients presenting a normal (n=18) or delayed time of intestinal visualization (n=18) at baseline hepatobiliary scintigraphy.Results: The mean treatment duration was 58±26 (S.D.) months and 63±29 months in the groups with normal or delayed time of intestinal visualization, respectively. The time of intestinal visualization decreased (57±23%, p<0.001) from baseline in patients with initially abnormal values and became normal in four (22%). Treatment failure, i.e. lack of sustained normalization of serum liver enzymes or the occurrence of a clinically relevant adverse event, was more frequently observed in patients with a normal time of intestinal visualization at baseline (OR, 5.50; 95% CI, 1.32–22.7). When only clinically relevant adverse events were considered, they occurred in six of the latter patients (liver transplantation in one case, development of ultrasographic or endoscopic signs of portal hypertension in six cases), but in only one patient (development of portal hypertension) in the group with delayed time of intestinal visualization (OR, 10.82; 95% CI, 1.17–100.4).Conclusions: Delayed intestinal visualization at hepatobiliary scintigraphy in patients with cystic fibrosisassociated liver disease seems to predict a better response to ursodeoxycholic acid.