Epidemiology of liver disease in cystic fibrosis: a longitudinal study

Pharmacokinetics of Ivacaftor, Tezacaftor, Elexacaftor, and Lumacaftor in Special Cystic Fibrosis Populations: A Systematic Review

BACKGROUND AND OBJECTIVE

Following the development of cystic fibrosis transmembrane conductance regulator (CFTR) modulators (ivacaftor, tezacaftor, elexacaftor, and lumacaftor), the prognosis for people diagnosed with cystic fibrosis (pwCF) has improved. Understanding the pharmacokinetics (PK) of CFTR modulators is crucial to provide optimal care, particularly in special cystic fibrosis (CF) populations such as pwCF with hepatic impairment, pancreatic insufficiency, those who are pregnant or lactating, or who are children. We aim to provide an overview of the PK of CFTR modulators in these populations.

METHODS

A systematic literature search was carried out in PubMed and Embase on 20 June 2024. Studies were considered relevant when information on PK or exposure of CFTR-modulating drugs was available.

RESULTS

PwCF with mild/moderate hepatic impairment do not exhibit substantially higher exposure to CFTR modulators compared with those without liver involvement or healthy individuals. Similarly, exocrine pancreatic insufficiency has no effect on the PK of CFTR modulators in adult pwCF. In contrast, pediatric pwCF are exposed to higher levels of CFTR modulators relative to adults, as children receive higher weight-based doses (mg/kg) to ensure equivalent therapeutic efficacy.

CONCLUSIONS

The PK of CFTR modulators have been more extensively studied in adults, pwCF with mild/moderate hepatic impairment, and children. However, ensuring adequate dosing remains challenging. Knowledge gaps persist for adults with severe hepatic impairment (Child-Pugh Class C), children with CF-induced hepatic impairment, and pregnant or lactating pwCF. Future research addressing these gaps, through incorporating routine clinical data, is crucial for improving clinical guidelines and optimizing dosing regimens, thereby advancing towards evidence-based utilization of CFTR modulators.

Identifying Gaps and Disparities in Screening for Cystic Fibrosis Associated Liver Disease: Insights From a CF Center Analysis

BACKGROUND

New 2023 CF liver disease (CFLD) guidelines advocate for additional screening in people with cystic fibrosis (PwCF), including biennial abdominal ultrasound. As a first step towards effective and equitable guidelines implementation, we examined our current practice of CFLD screening and hepatobiliary involvement (HBI) evaluation. We identified characteristics of PwCF at-risk for incomplete screening and factors affecting evaluation.

METHODS

We retrospectively reviewed medical records of PwCF aged 0-21 years, with native liver and ≥ 2 outpatient CF clinic visits 2017-2023. Logistic regression was used to identify characteristics associated with incomplete screening and with HBI.

RESULTS

Amongst 112 PwCF at our center: 37% (n = 42) self-reported as mixed race, 27% (n = 30) as Hispanic; 53% (n = 59) had public insurance. Incomplete lab screening was identified in 19% of our cohort. GGT was the most frequently missed component (14%, n = 16). Hispanics and publicly insured people were more likely to have incomplete screening. Of the 112, 45 met criteria for HBI. Demographics did not predict HBI. Five with CF and HBI had the full hepatitis workup recommended by the new guidelines. Those with HBI documented (42%, n = 19) were more likely to receive additional workup. PwCF who were seen by a gastroenterologist were more likely to have additional diagnostic work-up for HBI.

CONCLUSION

One in five PwCF at our center were incompletely screened for CFLD, with Hispanics and publicly insured at higher risk. Accurate diagnosis and adequate documentation are the first steps to identifying HBI in PwCF. A dedicated CF gastroenterologist is key to completing CFLD screening and liver diagnosis.

Early detection of hepatobiliary involvement in cystic fibrosis: Biomarkers, radiologic methods, and genetic influences

Cystic fibrosis-related hepatobiliary involvement (CFHBI) is a term used to describe a spectrum of hepatobiliary involvement ranging from a transient elevation of transaminase levels to advanced cystic fibrosis-associated liver disease (aCFLD). While CFHBI is common among people with cystic fibrosis (PwCF), aCFLD is rare impacting only approximately 5%-10% of the CF population. After respiratory/cardiorespiratory issues and transplant-related complications, aCFLD is now the 4th leading cause of mortality among PwCF. Additionally, aCFLD is an independent predictor of all-cause mortality and is associated with significant morbidity. Despite this recognition, our ability to predict those patients at greatest risk for aCFLD, identify early aCFLD, and monitor the incremental progression of CFHBI is lacking. Here, we review the strengths and weaknesses of the common biomarkers and imaging modalities used in the evaluation and monitoring of CFHBI, as well as the current understanding of genetic modifiers related to aCFLD.

Advanced cystic fibrosis liver disease: Endovascular, endoscopic, radiologic, and surgical considerations

Up to 90% of people with CF (pwCF) will have some form of hepatobiliary involvement. This manuscript aims to explore the different endovascular, endoscopic, radiological and surgical procedures available to diagnose and manage the most severe form of CF hepatobiliary involvement (CFHBI) known as advanced cystic fibrosis liver disease (aCFLD), seen in 10% of pwCF. These procedures and interventions include liver biopsy, hepatic venous pressure gradient measurement, gastrostomy tube placement to optimize nutrition, paracentesis, endoscopic variceal control of bleeding and portosystemic shunting before liver transplantation. By utilizing advanced diagnostic or surgical techniques, healthcare professionals of pwCF can more effectively manage patients with CFHBI and aCFLD and potentially improve patient outcomes.

Single-cell RNA sequencing of cystic fibrosis liver disease explants reveals endothelial complement activation

BACKGROUND & AIMS

Cystic fibrosis (CF) is considered a multisystemic disorder in which CF-associated liver disease (CFLD) is the third most common cause of mortality. Currently, no effective treatment is available for CFLD because its pathophysiology is still unclear. Interestingly, CFLD exhibits identical vascular characteristics as non-cirrhotic portal hypertension, recently classified as porto-sinusoidal vascular disorders (PSVD).

METHODS

Since endothelial cells (ECs) are an important component in PSVD, we performed single-cell RNA sequencing (scRNA-seq) on four explant livers from CFLD patients to identify differential endothelial characteristics which could contribute to the disease. We comprehensively characterized the endothelial compartment and compared it with publicly available scRNA-seq datasets from cirrhotic and healthy livers. Key gene signatures were validated ex vivo on patient tissues.

RESULTS

We found that ECs from CF liver explants are more closely related to healthy than cirrhotic patients. In CF patients we also discovered a distinct population of liver sinusoidal ECs-coined CF LSECs-upregulating genes involved in the complement cascade and coagulation. Finally, our immunostainings further validated the predominant periportal location of CF LSECs.

CONCLUSIONS

Our work showed novel aspects of human liver ECs at the single-cell level thereby supporting endothelial involvement in CFLD, and reinforcing the hypothesis that ECs could be a driver of PSVD. Therefore, considering the vascular compartment in CF and CFLD may help developing new therapeutic approaches for these diseases.

SHIFTing goals in cystic fibrosis-managing extrapulmonary disease in the era of CFTR modulator therapy; Proceedings of the International Shaping Initiatives and Future Trends (SHIFT) Symposium

BACKGROUND

Cystic fibrosis (CF) is a life-shortening multisystem genetic disease. Although progressive pulmonary disease is the predominant cause of morbidity and mortality, improvements in treatment for CF-related lung disease, with associated increase in longevity, have increased the prevalence of extrapulmonary manifestations1.

METHODS

To discuss these issues, a multidisciplinary meeting of international leaders and experts in the field was convened in November 2021 at the Shaping Initiatives and Future Trends  Symposium with the goal of highlighting shifting management paradigms in CF. The main topics covered were: (1) nutrition and obesity, (2) exocrine pancreas, (3) CF-related diabetes, (4) CF liver disease, (5) CF-related bone disease, and (6) post-lung transplant care. This document summarizes the proceedings, highlighting the key priorities and important research questions that were discussed.

RESULTS

Improved life expectancy, the advent of cystic fibrosis transmembrane conductance regulator modulators, and the increasing appreciation of the heterogeneity or spectrum of disease are leading to a shift in management for patients with cystic fibrosis. Care should be individualized to ensure that increased longevity is accompanied by improved extra-pulmonary care and reduced morbidity.

A Unique Mutation in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Gene Causing Cystic Fibrosis in a Pakistani Child: A Case Highlighting the Need for More Awareness

Cystic fibrosis (CF) is a recessively inherited disease most commonly seen in Caucasians. The mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene are responsible for the condition, and to date, more than 2000 mutations have been published in the literature. The most common mutation worldwide is F508del. Here, we reported a five-year-old child who presented to the clinic with a chronic cough. Her newborn screening for CF was negative, including 139 mutation panels done in India. The sweat chloride test was positive, and CF gene sequencing was reported as c.2489dup p. (Glu831GLYFS *5) homozygotes mutation in the CFTR gene (Online Mendelian Inheritance in Man (OMIM) *602421). To the best of our knowledge, this gene was first described and published in the literature.

A Gastroenterologist's Guide to Care Transitions in Cystic Fibrosis from Pediatrics to Adult Care

Cystic Fibrosis is a chronic disease affecting multiple systems, including the GI tract. Clinical manifestation in patients can start as early as infancy and vary across different age groups. With the advent of new, highly effective modulators, the life expectancy of PwCF has improved significantly. Various GI aspects of CF care, such as nutrition, are linked to an overall improvement in morbidity, lung function and the quality of life of PwCF. The variable clinical presentations and management of GI diseases in pediatrics and adults with CF should be recognized. Therefore, it is necessary to ensure efficient transfer of information between pediatric and adult providers for proper continuity of management and coordination of care at the time of transition. The transition of care is a challenging process for both patients and providers and currently there are no specific tools for GI providers to help ensure a smooth transition. In this review, we aim to highlight the crucial features of GI care at the time of transition and provide a checklist that can assist in ensuring an effective transition and ease the challenges associated with it.

Lung transplantation for cystic fibrosis complicated by cirrhosis: A case report

A 16-year-old girl with a genetic diagnosis of cystic fibrosis was referred to us for consideration of lung transplantation. She had been hospitalized repeatedly for pneumonia and pneumothoraxes and her respiratory function had worsened progressively. Although she also had liver cirrhosis, she was considered a candidate for lung transplantation because her liver disease was compensated and only slowly progressive. After bilateral lung transplantation from a brain-dead donor, she developed ascites that was well controlled with diuretics. Otherwise, her post-operative course was uneventful and she was transferred to another hospital for rehabilitation 39 days after lung transplantation.

Cystic fibrosis-related liver disease is an independent risk factor for mortality and increased health care resource utilization in hospitalized pediatric patients with cystic fibrosis

BACKGROUND

Cystic fibrosis-related liver disease (CFLD) is more prevalent in recent decades due to the increasing life expectancy of patients with cystic fibrosis (CF). There is paucity of population-level data on the impact of CFLD on hospital outcomes.

METHODS

We interrogated nonoverlapping years (2003-2016) of the National Inpatient Sample and Kids' Inpatient Database to include all hospitalized patients <21 years of age with a primary diagnosis of CF within the United States. A concomitant diagnosis of cirrhosis, liver fibrosis, chronic liver disease, portal hypertension, hepatomegaly, splenomegaly, hypersplenism, and liver transplant status was considered as surrogates for the diagnosis of CFLD and was compared with CF-related hospitalizations without these diagnoses (controls) for demographics, comorbid conditions, in-hospital mortality, length-of-stay, and hospital charges.

RESULTS

We evaluated 94,374 CF-related hospitalizations. The prevalence of CFLD was 5.8%. The prevalence increased from 3.1% (2003) to a peak of 7.3% (2014) with an overall increasing trend, p < 0.001. Hospitalizations with CFLD had an increased prevalence of significant comorbidities: respiratory failure,lung transplant, pulmonary hypertension, diabetes mellitus, malnutrition, Clostridioides difficile infection, cholelithiasis, anemia, and need for parenteral nutrition, p < 0.001. Multivariate regression models showed CFLD as independently associated with 2.1 (95% confidence interval [CI]: 1.5 to 2.8) times increased risk of inpatient mortality, contributed to 1.1 (95% CI: 0.89 to 1.37) additional days of hospitalization, and incurring $14,852 (95% CI: 12,204 to 17,501) excess hospital charges, p < 0.001.

CONCLUSION

CFLD is associated with multiple comorbidities and is independently associated with increased risk of mortality and increased health care resource utilization in pediatric CF-related hospitalizations.

Pancreatic, hepatobiliary, and gastrointestinal manifestations of children with cystic fibrosis: A 10-year experience from a tertiary care center in southern India

OBJECTIVES

To describe the demography and spectrum of pancreatic, hepatobiliary, and gastrointestinal (GI) manifestations in children with cystic fibrosis (CF) from the Indian subcontinent.

METHODS

In this retrospective study, relevant information from the database of all children with CF below 18 years of age was collected and analyzed.

RESULTS

Among the total 109 children, 58 (53%) were from the southern states of India. The most common manifestation was pancreatic insufficiency (PI) in 85 (83%) children. Those with PI presented at an earlier age (1.8 vs. 6.9 years). Cirrhosis with portal hypertension was documented in only one patient and meconium ileus in three (2.8%). There was significant malnutrition in the PI cohort with a mean weight-for-age Z-score of - 3.17 ± 1.79 at diagnosis. Twenty-one (19%) patients had died during the follow-up and 18 (90%) of them had PI. There was no difference in the prevalence of selected pulmonary manifestations in the PI and pancreatic sufficient (PS) groups. Among children with PI, 78 were screened for ΔF508 mutation, 16 (21%) were homozygous, and 17 (22%) were heterozygous. In the PS group, only 2 (14%) were heterozygous for ΔF508 mutation. The median duration of follow-up of the patients was 1.8 (1.5) years.

CONCLUSION

PI is the most common GI manifestation of children with CF and is associated with severe malnutrition and poor outcome. Timely identification and management of the comorbidities involving the digestive system are essential for better growth and quality of life in these children.

Cystic fibrosis related liver disease and endocrine considerations

Cystic fibrosis-liver disease (CFLD) is one of the most common non-pulmonary complications in the CF population, is associated with significant morbidity and represents the third leading cause of mortality in those with CF. CFLD encompasses a broad spectrum of hepatobiliary manifestations ranging from mild transaminitis, biliary disease, hepatic steatosis, focal biliary cirrhosis and multilobular biliary cirrhosis. The diagnosis of CFLD and prediction of disease progression remains a clinical challenge. The identification of novel CFLD biomarkers as well as the role of newer imaging techniques such as elastography to allow for early detection and intervention are active areas of research focus. Biliary cirrhosis with portal hypertension represents the most severe spectrum of CFLD, almost exclusively develops in the pediatric population, and is associated with a decline in pulmonary function, poor nutritional status, and greater risk of hospitalization. Furthermore, those with CFLD are at increased risk for vitamin deficiencies and endocrinopathies including CF-related diabetes, CF-related bone disease and hypogonadism, which can have further implications on disease outcomes and management. Effective treatment for CFLD remains limited and current interventions focus on optimization of nutritional status, identification and treatment of comorbid conditions, as well as early detection and management of CFLD specific sequelae such as portal hypertension or variceal bleeding. The extent to which highly effective modulator therapies may prevent the development or modify the progression of CFLD remains an active area of research. In this review, we discuss the challenges with defining and evaluating CFLD and the endocrine considerations and current management of CFLD.

Understanding Cystic Fibrosis Comorbidities and Their Impact on Nutritional Management

Cystic fibrosis (CF) is a chronic, multisystem disease with multiple comorbidities that can significantly affect nutrition and quality of life. Maintaining nutritional adequacy can be challenging in people with cystic fibrosis and has been directly associated with suboptimal clinical outcomes. Comorbidities of CF can result in significantly decreased nutritional intake and intestinal absorption, as well as increased metabolic demands. It is crucial to utilize a multidisciplinary team with expertise in CF to optimize growth and nutrition, where patients with CF and their loved ones are placed in the center of the care model. Additionally, with the advent of highly effective modulators (HEMs), CF providers have begun to identify previously unrecognized nutritional issues, such as obesity. Here, we will review and summarize commonly encountered comorbidities and their nutritional impact on this unique population.

Cystic fibrosis-related liver disease: Clinical presentations, diagnostic and monitoring approaches in the era of CFTR modulator therapies

Cystic fibrosis (CF) is the most common autosomal recessive disease in the Caucasian population. Cystic fibrosis-related liver disease (CFLD) is defined as the pathogenesis related to the underlying CFTR defect in biliary epithelial cells. CFLD needs to be distinguished from other liver manifestations that may not have any pathological significance. The clinical/histological presentation and severity of CFLD vary. The main histological presentation of CFLD is focal biliary fibrosis, which is usually asymptomatic. Portal hypertension develops in a minority of cases (about 10%) and may require specific management including liver transplantation for end-stage liver disease. Portal hypertension is usually the result of the progression of focal biliary fibrosis to multilobular cirrhosis during childhood. Nevertheless, non-cirrhotic portal hypertension as a result of porto-sinusoidal vascular disease is now identified increasingly more frequently, mainly in young adults. To evaluate the effect of new CFTR modulator therapies on the liver, the spectrum of hepatobiliary involvement must first be precisely classified. This paper discusses the phenotypic features of CFLD, its underlying physiopathology and relevant diagnostic and follow-up approaches, with a special focus on imaging.

Cystic fibrosis and noninvasive liver fibrosis assessment methods in children

BACKGROUND

Noninvasive assessments of liver fibrosis are currently used to evaluate cystic fibrosis (CF)-related liver disease. However, there is scarce data regarding their repeatability and reproducibility, especially in children with CF. The present study aimed to evaluate the repeatability and reproducibility of transient elastography (TE) (FibroScan®) and point shear-wave elastography using virtual touch quantification (pSWE VTQ) in children with CF.

METHODS

TE and pSWE VTQ were performed in 56 children with CF by two different operators. Analysis of repeatability and reproducibility was available in 33 patients for TE and 46 patients for pSWE VTQ. Intra- and interobserver agreement were assessed using the intraclass correlation coefficient (ICC) and their 95% confidence interval (CI), and Bland and Altman graphs.

RESULTS

For TE, ICC was 0.91 (0.83-0.95) for intraobserver agreement and 0.92 (95% CI: 0.86-0.96) for interobserver agreement. For pSWE VTQ, ICC was 0.83 (0.72-0.90) for intraobserver agreement and 0.67 (0.48-0.80) for interobserver agreement.

CONCLUSIONS

Both technics can be proposed in the follow-up of patients, according to their availability in CF centers.

IMPACT

This study shows that TE and pSWE VTQ are reliable methods to evaluate liver fibrosis in children with CF. This study shows for the first time that TE and pSWE VTQ are both repeatable and reproducible in children with CF. These data indicate that both TE and pSWE VTQ can be proposed for the follow-up of patients with CF, according to their availability in each CF center.

Cystic fibrosis associated liver disease in children

Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the CF transmembrane conductance regulator gene. CF liver disease develops in 5%-10% of patients with CF and is the third leading cause of death among patients with CF after pulmonary disease or lung transplant complications. We review the pathogenesis, clinical presentations, complications, diagnostic evaluation, effect of medical therapies especially CF transmembrane conductance regulator modulators and liver transplantation in CF associated liver disease.

Characteristics and Outcomes of Children With Cystic Fibrosis Hospitalized With Cirrhosis in the United States

INTRODUCTION

To describe the characteristics and outcomes of children with cystic fibrosis (CF) hospitalized with cirrhosis in the United States.

METHODS

We conducted a population-based cohort study of hospitalizations among children with CF using the 2016 Kid's Inpatient Database.

RESULTS

In total, 9,615 admissions were analyzed. Diagnosis of cirrhosis was present in 509 (5.3%) and was significantly associated with increased mortality, length of stay, and hospital charges compared with those without cirrhosis. Hepatic encephalopathy was significantly associated with death in children with cirrhosis.

DISCUSSION

Future interventions should be designed to support children with CF who have cirrhosis to improve clinical outcomes.

Early intrahepatic duct defects in a cystic fibrosis porcine model

Hepatobiliary disease causes significant morbidity and mortality in people with cystic fibrosis (CF), yet this problem remains understudied. Previous studies in the newborn CF pig demonstrated decreased bile flow into the small intestine and a microgallbladder with increased luminal mucus and fluid secretion defects. In this study, we examined the intrahepatic bile ducts of the newborn CF pig. We assessed whether our findings from the gallbladder are present elsewhere in the porcine biliary tract and if CF pig cholangiocytes have fluid secretion defects. Immunohistochemistry demonstrated apical CFTR expression in non-CF pig intrahepatic bile ducts of a variety of sizes; CF pig intrahepatic bile ducts lacked CFTR expression. Assessment of serum markers did not reveal significant signs of hepatobiliary disease except for an elevation in direct bilirubin. Quantitative histology demonstrated that CF pigs had smaller bile ducts that more frequently contained luminal mucus. CF intrahepatic cholangiocyte organoids were smaller and lacked cAMP-mediated fluid secretion. Together these data suggest that cholangiocyte fluid secretion is decreased in the CF pig, contributing to structural changes in bile ducts and decreased biliary flow.

Combined Liver-Lung-Kidney Transplant in a Patient with Cystic Fibrosis

BACKGROUND Individuals with cystic fibrosis (CF) constituted approximately 10% of organ transplants in 2019, with the majority of transplants consisting of bilateral lung transplant. Multiorgan transplantation in individuals with cystic fibrosis (CF) is rare, and usually involves the liver and lung combined. Since kidney disease is not a common sequela of CF, the need for renal transplant in individuals who have not previously undergone lung transplant is uncommon. CASE REPORT We report a case of successful liver-lung-kidney transplant in a 23-year-old man with CF-related liver and lung disease, who developed renal failure due to IgA nephropathy. He required renal replacement therapy during the months before transplantation. After discussions among the liver, lung, and renal transplant teams, the patient was listed for multiorgan transplantation. An appropriate single donor for all organs was identified, and the patient underwent transplantation. The patient required extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT) perioperatively, with total operative time of 23 h and 1 min. Postoperative course was notable for hemothorax and medication-induced acute tubular necrosis, which resolved without the need for renal replacement therapy. Liver and lung graft function was normal at 6 months, and renal function was minimally reduced. CONCLUSIONS Triple organ transplantation in CF is a viable option for individuals with multiorgan failure who may otherwise not qualify for single/dual organ transplantation. Use of ECMO and CRRT can be necessary during the long operative procedure. Optimal immunosuppression protocols for this group of patients has not yet been established, and ethical concerns regarding multiorgan transplantation exist.

A review of liver dysfunction in the lung transplant patient

Liver dysfunction is an increasingly common finding in patients evaluated for lung transplantation. New or worsening dysfunction in the perioperative period, defined by presence of clinical ascites/encephalopathy, high model for end-stage liver disease (MELD) score, and/or independent diagnostic criteria, is associated with high short- and long-term mortality. Therefore, a thorough liver function assessment is necessary prior to listing for lung transplant. Unfortunately, identification and intraoperative monitoring remain the only options for prevention of disease progression with isolated lung transplantation. Combined lung and liver transplantation may provide an option for definitive long-term management in selecting patients with known liver disease at high risk for postoperative progression. However, experience with the combined operation is extremely limited and indications for combined lung and liver transplant remain unclear. Herein, we present a comprehensive literature review of patients with liver dysfunction undergoing lung transplantation with and without concurrent liver transplant in an effort to illuminate the risks, benefits, and clinical judgement surrounding decision to pursue combined lung-liver transplantation (CLLT). We also argue description of liver function is currently a weakness of the current lung allocation scoring system. Additional algorithms incorporating liver function may aid in risk stratification and decision to pursue combined transplantation.

Ursodeoxycholic acid and liver disease associated with cystic fibrosis: A multicenter cohort study

BACKGROUND

The efficacy and safety of ursodeoxycholic acid (UDCA) for the treatment of liver disease associated with cystic fibrosis (CF) are under discussion, and clinical practice varies among centers. The study aimed at evaluating if the incidence of severe liver disease differs between CF centers routinely prescribing or not prescribing UDCA.

METHODS

We carried out a retrospective multicenter cohort study including 1591 CF patients (1192 patients from UDCA-prescribing centers and 399 from non-prescribing centers) born between 1990 and 2007 and followed from birth up to 31 December 2016. We computed the crude cumulative incidence (CCI) of portal hypertension (PH) at the age of 20 years in the two groups and estimated the subdistribution hazard ratio (HR) through a Fine and Gray model.

RESULTS

Over the observation period, 114 patients developed PH: 90 (7.6%) patients followed-up in UDCA prescribing centers and 24 (6.0%) in non-prescribing centers. The CCI of PH at 20 years was 10.1% (95% CI: 7.9-12.3) in UDCA-prescribing and 7.7% (95% CI: 4.6-10.7) in non-prescribing centers. The HR among patients followed in prescribing centers indicated no significant difference in the rate of PH either in the unadjusted model (HR: 1.21, 95% CI: 0.69-2.11) or in the model adjusted for pancreatic insufficiency (HR: 1.28, 95% CI: 0.77-2.12).

CONCLUSIONS

CF patients followed-up in UDCA prescribing centers did not show a lower incidence of PH as compared to those followed in centers not prescribing UDCA. These results question the utility of UDCA in reducing the occurrence of severe liver disease in CF.

Cystic fibrosis liver disease in Newfoundland and Labrador: a prevalence study

Background: Liver disease in patients with cystic fibrosis (CF) is an understudied and increasingly common concern. The prevalence of cystic fibrosis liver disease (CFLD) in Canada has not been clearly established, although it is now the third leading cause of death among patients with CF. The current literature identifies a range in prevalence from 4% to 65%, which implies the need for further research. This study aimed to determine the prevalence of CFLD among adult patients with CF in Newfoundland and Labrador. Methods: Charts of patients with CF from the St. John’s, Newfoundland, CF clinics were reviewed retrospectively for the presence of elevated liver enzymes, imaging or biopsy of the liver, and other etiologies of liver disease. Prevalence was determined for patients meeting the criteria for CFLD in the population as a whole and for those who had undergone all pertinent investigations. Results: The diagnostic guidelines for CFLD were met in 14 of 57 cases (24.6% prevalence). Severe CFLD was present in 9 patients (15.8%). Among all patients with CF, 33 (57.9%) had isolated liver enzyme elevation. Eleven patients had not had the requisite imaging performed for accurate diagnosis. Among the subset who had undergone imaging, the prevalence of CFLD was 30%. Conclusions: This study attempted to fill the gap in Canadian CFLD prevalence data by examining the population with CF in Newfoundland and Labrador. The prevalence of CFLD was found to be between 25% and 30%. More accurate determination of prevalence could be done with future cross-sectional or prospective studies.

Current Treatment Options for Cystic Fibrosis-Related Liver Disease

Cystic Fibrosis-related liver disease (CFLD) has become a leading cause of morbidity and mortality in patients with Cystic Fibrosis (CF), and affects children and adults. The understanding of the pathogenesis of CFLD is key in order to develop efficacious treatments. However, it remains complex, and has not been clarified to the last. The search for a drug might be additionally complicated due to the diverse clinical picture and lack of a unified definition of CFLD. Although ursodeoxycholic acid has been used for decades, its efficacy in CFLD is controversial, and the potential of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulators and targeted gene therapy in CFLD needs to be defined in the near future. This review focuses on the current knowledge on treatment strategies for CFLD based on pathomechanistic viewpoints.

Extended Screening for Cystic Fibrosis-related Liver Disease Including Elastography in Children and Adolescents

OBJECTIVES

Advances in treatment of cystic fibrosis (CF) have increased survival and thereby prevalence of patients with liver disease, making chronic liver disease one of the major complications of CF. We describe the prevalence of liver fibrosis, portal hypertension, and liver decompensation by extended screening for cystic fibrosis-related liver disease (CFLD) including ultrasound, elastography, and an extended panel of biochemical markers.

METHODS

A cross sectional study of CFLD in all pediatric CF patients (1-18 years) from the Copenhagen CF Center. Screening for liver disease included physical examination, biochemical analysis, Vibration-Controlled Transient Elastography (FibroScan), conventional ultrasound, and Real-Time Shear Wave elastography (SWE). Patients were scored according to Williams ultrasound scoring scale (WUSS) within 6 months.

RESULTS

A total of 84 consecutive patients (male sex 46.4%, median age 10.4 years) were included. Eight patients (9.5%) had both ≥2 abnormal results of sonographic methods and ≥2 abnormal biochemical results and were in this study categorized as having manifest CFLD. Manifest CFLD patients were significantly older and had a higher mean value of APRI, but no differences in gender, z-height, z-weight, z-BMI, FEV1%, or mean value of bilirubin or albumin were found.

CONCLUSIONS

In total, 8 patients (9.5%) in this pediatric CF population were categorized as having CFLD according to both biochemical and sonographic tests. Consistency was found among the results of FibroScan and SWE. We suggest WUSS and either FibroScan or SWE, combined with GGT as diagnostic markers for CFLD.

Early pathogenesis of cystic fibrosis gallbladder disease in a porcine model

Hepatobiliary disease causes significant morbidity in people with cystic fibrosis (CF), yet this problem remains understudied. We previously found that newborn CF pigs have microgallbladders with significant luminal obstruction in the absence of infection and consistent inflammation. In this study, we sought to better understand the early pathogenesis of CF pig gallbladder disease. We hypothesized that loss of CFTR would impair gallbladder epithelium anion/liquid secretion and increase mucin production. CFTR was expressed apically in non-CF pig gallbladder epithelium but was absent in CF. CF pig gallbladders lacked cAMP-stimulated anion transport. Using a novel gallbladder epithelial organoid model, we found that Cl- or HCO3- was sufficient for non-CF organoid swelling. This response was absent for non-CF organoids in Cl-/HCO3--free conditions and in CF. Single-cell RNA-sequencing revealed a single epithelial cell type in non-CF gallbladders that coexpressed CFTR, MUC5AC, and MUC5B. Despite CF gallbladders having increased luminal MUC5AC and MUC5B accumulation, there was no significant difference in the epithelial expression of gel-forming mucins between non-CF and CF pig gallbladders. In conclusion, these data suggest that loss of CFTR-mediated anion transport and fluid secretion contribute to microgallbladder development and luminal mucus accumulation in CF.

Encephalopathy in cystic fibrosis

Cystic fibrosis liver disease (CFLD) affects a large proportion of cystic fibrosis (CF) patients; however encephalopathy is a rare complication. While classical hepatic encephalopathy can be a feature of end-stage liver disease, "hyperammonemic encephalopathy" can be precipitated in previously stable CFLD by various triggers including systemic corticosteroids. We describe one such case and review the relevant literature.

Epithelial vectorial ion transport in cystic fibrosis: Dysfunction, measurement, and pharmacotherapy to target the primary deficit

Cystic fibrosis patients display multi-organ system dysfunction (e.g. pancreas, gastrointestinal tract, and lung) with pathogenesis linked to a failure of Cl^- secretion from the epithelial surfaces of these organs. If unmanaged, organ dysfunction starts early and patients experience chronic respiratory infection with reduced lung function and a failure to thrive due to gastrointestinal malabsorption. Early mortality is typically caused by respiratory failure. In the past 40 years of newborn screening and improved disease management have driven the median survival up from the mid-teens to 43-53, with most of that improvement coming from earlier and more aggressive management of the symptoms. In the last decade, promising pharmacotherapies have been developed for the correction of the underlying epithelial dysfunction, namely, Cl^- secretion. A new generation of systemic drugs target the mutated Cl^- channels in cystic fibrosis patients and allow trafficking of the immature mutated protein to the cell membrane (correctors), restore function to the channel once in situ (potentiators), or increase protein levels in the cells (amplifiers). Restoration of channel function prior to symptom development has the potential to significantly change the trajectory of disease progression and their evidence suggests that a modest restoration of Cl^- secretion may delay disease progression by decades. In this article, we review epithelial vectorial ion and fluid transport, its quantification and measurement as a marker for cystic fibrosis ion transport dysfunction, and highlight some of the recent therapies targeted at the dysfunctional ion transport of cystic fibrosis.

Cystic Fibrosis-related Liver Disease is Associated With Increased Disease Burden and Endocrine Comorbidities

BACKGROUND

Cystic fibrosis-related liver disease (CFLD) is the leading nonpulmonary cause of mortality in cystic fibrosis (CF). We evaluated and compared the burden of disease and nonrespiratory comorbidities of those with severe CFLD and those without (noCFLD).

METHODS

A retrospective nationwide (Australia) longitudinal review (from 1998 to 2016) of severe CFLD patients compared with noCFLD controls (matched 1 : 1 for age, genotype, pancreatic insufficiency, and center).

RESULTS

One hundred sixty-six patients with severe CFLD and 166 with noCFLD were identified. Forced expiratory volume in 1 second percentage of predicted (FEV1%) was significantly lower in CFLD than noCFLD across all ages (estimate [SE] -6.05% [2.12]; P = 0.004). Median (IQR) hospitalizations per patient per year were higher in CFLD than noCFLD for: respiratory indications (0.6 [0.2-1.3] vs 0.4 [0.1-0.9]; P = 0.002); gastrointestinal indications (0.09 [0-0.2] vs 0 [0-0.05]; P < 0.001); and other indications (0.05 [0-0.2] vs 0 [0-0.1]; P = 0.03). In the CFLD cohort, there was increased use of nasogastric (12.6% vs 5.4%; OR 2.51 [95% CI 1.06-6.46]; P = 0.03) and gastrostomy nutritional supplementation (22.9% vs 13.2%; OR 1.93 [95% CI 1.05-3.63]; P = 0.03). Additionally, the CFLD cohort had a higher frequency of bone diseases, osteopenia (26.5% vs 16.8%; OR 1.77 [95%CI 1.01-3.15]; P = 0.04) and osteoporosis (16.2% vs 8.4%; OR 2.1 [95% CI 1.01-4.52]; P = 0.04), as well as CF-related diabetes (38.5% vs 19.2%; OR 2.61 [95% CI 1.55-4.47]; P = 0.001).

CONCLUSIONS

Patients with severe CFLD have greater disease burden, with higher number of hospitalizations (both respiratory and nonrespiratory indications), nutritional interventions, and are at higher risk of CF-related bone disease and diabetes.

A longitudinal assessment of non-invasive biomarkers to diagnose and predict cystic fibrosis-associated liver disease

BACKGROUND & AIMS

A practical, inexpensive, and non-invasive biomarker of liver fibrosis is needed as a reliable screening test for cystic fibrosis-associated liver disease (CFLD). Studies have shown the utility of AST to Platelet Ratio Index (APRI), fibrosis index based on 4 factors (FIB-4), and gamma-glutamyl transferase (GGT) as good biomarkers for identifying CFLD. The goal of the study was to evaluate the effectiveness of APRI, FIB-4, AST/ALT ratio, platelet count, GGT, and GGT platelet ratio (GPR) in predicting CFLD development.

METHODS

Data was collected from CF Foundation Patient Registry for patients aged 3-21 years at Johns Hopkins from January 1, 2002 to December 31, 2014. Collected data included demographic characteristics, presence of splenomegaly, hepatomegaly, ascites, and variceal bleeding, AST, ALT, GGT, platelet count, and FEV₁. The sensitivity and specificity of each biomarker were analyzed and reported by the area under receiver operating characteristic (AUROC) curve.

RESULTS

By the end of the study, 144 "healthy" CF, 12 CFLD, 19 CF-associated pulmonary disease (CFPD), and 4 CFLD with CFPD cases were identified. APRI scores were higher in CFLD, 0.85 versus 0.28 in "healthy" CF and 0.23 in CFPD groups (p<0.001). GPR had the highest AUROC curve at 0.91.

CONCLUSIONS

GPR, GGT, APRI score, and platelet count were potentially useful biomarkers while FIB-4 did not predict CFLD development. Cost-effectiveness studies are needed to analyze the utility of these biomarkers in clinical practice.

Cystic fibrosis-associated liver disease in children

As improvements in nutritional and pulmonary care increase the life expectancy of cystic fibrosis (CF) patients, CF-associated liver disease (CFLD) is emerging as a cause of mortality. CFLD is the third leading cause of death in CF patients. We performed a search on PubMed and Google Scholar for published articles on CFLD. We reviewed the articles found in the literature search and gave priority to recent publications and studies with larger sample sizes. The prevalence of CFLD in the CF population is around 23% with a range of 2-62% and that prevalence increases linearly with age from 3.7% at age 5 to 32.2% at age 30. CFLD can present clinically in various ways such as hepatomegaly, variceal hemorrhage, persistent elevation of liver enzymes, and micro-gallbladder. Due to the focal nature of fibrosis in majority cases of CFLD, liver biopsies are sparsely performed for diagnosis or the marker of liver fibrosis. Although the mechanism of CFLD development is still unknown, many potential factors are reported. Some mutations of CFTR such as having a homozygous F508del mutation has been reported to increase the risk of developing CFLD and its severity. Having the SERPINA1 Z allele, a history of pancreatic insufficiency, a history meconium ileus, CF-related diabetes, or being male increases the risk of developing CFLD. Environmental factors do not appear to have significant effect on modulating CFLD development. Ursodeoxycholic acid is commonly used to treat or prevent CFLD, but the efficacy of this treatment is questionable.

Interventions for preventing and managing advanced liver disease in cystic fibrosis

BACKGROUND

Cystic fibrosis is an autosomal recessive inherited defect in the cystic fibrosis transmembrane conductance regulator (CFTR) gene resulting in abnormal regulation of salt and water movement across the membranes. In the liver this leads to focal biliary fibrosis resulting in progressive portal hypertension and end-stage liver disease in some individuals. This can be asymptomatic, but may lead to splenomegaly and hypersplenism, development of varices and variceal bleeding, and ascites; it has negative impact on overall nutritional status and respiratory function in this population. Prognosis is poor once significant portal hypertension is established. The role and outcome of various interventions for managing advanced liver disease (non-malignant end stage disease) in people with cystic fibrosis is currently unidentified. This is an updated version of a previously published review.

OBJECTIVES

To review and assess the efficacy of currently available treatment options for preventing and managing advanced liver disease in children and adults with cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Date of last search: 19 November 2019. We also searched the reference lists of relevant articles and reviews and online trials registries. Date of last search: 01 January 2020.

SELECTION CRITERIA

Any published and unpublished randomised controlled trials and quasi-randomised controlled trials of advanced liver disease in cystic fibrosis with cirrhosis or liver failure, portal hypertension or variceal bleeding (or both).

DATA COLLECTION AND ANALYSIS

Authors independently examined titles and abstracts to identify potentially relevant trials, but none were eligible for inclusion in this review.

MAIN RESULTS

A comprehensive search of the literature did not identify any published eligible randomised controlled trials.

AUTHORS' CONCLUSIONS

In order to develop the best source of evidence, there is a need to undertake randomised controlled trials of interventions for preventing and managing advanced liver disease in adults and children with cystic fibrosis.

Impaired Intestinal Farnesoid X Receptor Signaling in Cystic Fibrosis Mice

BACKGROUND & AIMS

The bile acid (BA)-activated farnesoid X receptor (FXR) controls hepatic BA synthesis and cell proliferation via the intestinal hormone fibroblast growth factor 19. Because cystic fibrosis (CF) is associated with intestinal dysbiosis, anomalous BA handling, and biliary cirrhosis, we investigated FXR signaling in CF.

METHODS

Intestinal and hepatic expression of FXR target genes and inflammation markers was assessed in Cftr null mice and controls. Localization of the apical sodium-dependent BA transporter was assessed, and BAs in gastrointestinal tissues were analyzed. The CF microbiota was characterized and FXR signaling was investigated in intestinal tissue and organoids.

RESULTS

Ileal murine fibroblast growth factor 19 ortholog (Fgf15) expression was strongly reduced in CF mice, compared with controls. Luminal BA levels and localization of apical sodium-dependent BA transporter was not affected, and BAs induced Fgf15 up to normal levels in CF ileum, ex vivo, and CF organoids. CF mice showed a dysbiosis that was associated with a marked up-regulation of genes involved in host-microbe interactions, including those involved in mucin glycosylation, antimicrobial defense, and Toll-like receptor signaling. Antibiotic treatment reversed the up-regulation of inflammatory markers and restored intestinal FXR signaling in CF mice. Conversely, FXR-dependent gene induction in ileal tissue and organoids was repressed by bacterial lipopolysaccharide and proinflammatory cytokines, respectively. Loss of intestinal FXR activity was associated with a markedly blunted hepatic trophic response to oral BA supplementation, and with impaired repression of Cyp7a1, the gene encoding the rate-limiting enzyme in BA synthesis.

CONCLUSIONS

In CF mice, the gut microbiota represses intestinal FXR activity, and, consequently, FXR-dependent hepatic cell proliferation and feedback control of BA synthesis.

Cystic fibrosis liver disease: A condition in need of structured transition and continuity of care

Liver disease affects one-third of patients with cystic fibrosis (CF) and it is one of the major causes of morbidity and mortality in these patients. Historically considered a disease of childhood, its impact is now seen more often in adulthood. The heterogeneous pattern of CF liver disease and its rapid progression to cirrhosis remain a diagnostic challenge and new questions pertaining to the nature of liver involvement have recently been raised. Non-invasive measures to stratify the severity of liver involvement are increasingly used to predict clinical outcomes. A single treatment, ursodeoxycholic acid, has been used to slow progression of liver disease while recent advances in the field of CF treatments are promising. Management of portal hypertension remains challenging but outcomes after liver transplantation are encouraging. While many questions remain unanswered, a growing number of CF patients reach adulthood and will require care for CF liver disease.

Pathophysiology of Cystic Fibrosis Liver Disease: A Channelopathy Leading to Alterations in Innate Immunity and in Microbiota

Cystic fibrosis (CF) is a monogenic disease caused by mutation of Cftr. CF-associated liver disease (CFLD) is a common nonpulmonary cause of mortality in CF and accounts for approximately 2.5%-5% of overall CF mortality. The peak of the disease is in the pediatric population, but a second wave of liver disease in CF adults has been reported in the past decade in association with an increase in the life expectancy of these patients. New drugs are available to correct the basic defect in CF but their efficacy in CFLD is not known. The cystic fibrosis transmembrane conductance regulator, expressed in the apical membrane of cholangiocytes, is a major determinant for bile secretion and CFLD classically has been considered a channelopathy. However, the recent findings of the cystic fibrosis transmembrane conductance regulator as a regulator of epithelial innate immunity and the possible influence of the intestinal disease with an altered microbiota on the liver complication have opened new mechanistic insights on the pathogenesis of CFLD. This review provides an overview of the current understanding of the pathophysiology of the disease and discusses a potential target for intervention.

Hepatic Manifestations of Cystic Fibrosis

Cystic fibrosis liver disease (CFLD) remains the third leading cause of death in patients with cystic fibrosis. Although most patients with CFLD present in childhood, recent studies suggest a second wave of liver disease in adulthood. There are no clear guidelines for diagnosing CFLD. Treatment options for CFLD remain limited, and while UDCA is widely used, its long-term benefit is unclear. Those who develop hepatic decompensation or uncontrolled variceal bleeding may benefit from liver transplant, either alone, or in combination with lung transplant.

The emerging burden of liver disease in cystic fibrosis patients: A UK nationwide study

Objective

Cystic fibrosis associated liver disease (CFLD) is the third largest cause of mortality in CF. Our aim was to define the burden of CFLD in the UK using national registry data and identify risk factors for progressive disease.

Methods

A longitudinal population-based cohort study was conducted. Cases were defined as all patients with CFLD identified from the UK CF Registry, 2008–2013 (n = 3417). Denominator data were derived from the entire UK CF Registry. The burden of CFLD was characterised. Regression analysis was undertaken to identify risk factors for cirrhosis and progression.

Results

Prevalence of CFLD increased from 203.4 to 228.3 per 1000 patients during 2008–2013. Mortality in CF patients with CFLD was more than double those without; cirrhotic patients had higher all-cause mortality (HR 1.54, 95% CI 1.09 to 2.18, p = 0.015). Median recorded age of cirrhosis diagnosis was 19 (range 5–53) years. Male sex, Pseudomonas airway infection and CF related diabetes were independent risk factors for cirrhosis. Ursodeoxycholic acid use was associated with prolonged survival in patients without cirrhosis.

Conclusions

This study highlights an important changing disease burden of CFLD. The prevalence is slowly increasing and, importantly, the disease is not just being diagnosed in childhood. Although the role of ursodeoxycholic acid remains controversial, this study identified a positive association with survival.

Cystic Fibrosis Liver Disease: Outcomes and Risk Factors in a Large Cohort of French Patients

Cystic fibrosis (CF)-related liver disease (CFLD) is a common symptom in patients with CF. However, its prevalence, risk factors, and evolution are unclear. We analyzed a large database of patients with CF to investigate the incidence of CFLD, its related risk factors, and the use and effect of ursodeoxycholic acid (UDCA) treatment. We retrospectively analyzed 3,328 CF patients with pancreatic insufficiency born after 1985 and recruited into the French CF Modifier Gene Study since 2004. We determined liver status, age at CFLD and severe CFLD onset, sex, CFTR genotype, history of meconium ileus, treatment with UDCA, and respiratory and nutritional status. The incidence of CFLD increased by approximately 1% every year, reaching 32.2% by age 25. The incidence of severe CFLD increased only after the age of 5, reaching 10% by age 30. Risk factors for CFLD and severe CFLD were male sex, CFTR F508del homozygosity, and history of meconium ileus. Increasingly precocious initiation of UDCA treatment did not change the incidence of severe CFLD. Finally, patients with severe CFLD had worse lung function and nutritional status than other CF patients. Conclusion: CFLD occurs not only during childhood but also later in the lifetime of patients with CF; male sex, CFTR F508del homozygosity, and history of meconium ileus are independent risk factors for CFLD development; earlier use of UDCA over the last 20 years has not changed the incidence of severe CFLD, leading to questions about the use of this treatment in young children given its possible adverse effects.

Modifier genes in cystic fibrosis-related liver disease

PURPOSE OF REVIEW

Cystic fibrosis (CF; OMIM 219700) is caused by variations in the cystic fibrosis transmembrane conductance regulator gene. CF-related liver disease (CFLD) affects approximately one-third of patients with CF, but the severity of CFLD is highly variable. This review provides the latest knowledge in the pathophysiology and CF genetic modifier research in CFLD.

RECENT FINDINGS

So far, the only modifier gene validated in CFLD is SERPINA1 (α-1-antitrypsin) Z allele. Recent studies support the view that cholangiopathy arising in CF is the result of an ill-adapted innate immune response to endotoxins coming from the intestine and triggering a pro-inflammatory response.

SUMMARY

The pathophysiology of liver disease remains uncertain and so far, no therapy has proven effective to prevent the progression of CFLD. A better understanding of the pathophysiology and the effect of environmental and non-cystic fibrosis transmembrane conductance regulator genetic influences in the context of CFLD development would help improve management and develop new drug therapies.

Hepatic Steatosis Is Prevalent Following Orthotopic Liver Transplantation in Children With Cystic Fibrosis

OBJECTIVES

Systematic study of allograft liver histology in children undergoing orthotopic liver transplantation (LT) for cystic fibrosis-related liver disease (CFLD).

METHODS

Retrospective clinicopathologic review of explants and allograft liver biopsies from 13 children and adolescents with CFLD.

RESULTS

In this study, the median age at LT for CFLD was 15.7 years. Notably, 10 of 13 (77%) CF explants had >5% steatosis and 8 of 13 (61.5%) demonstrated variable fibrosis. The median age, sex, type of transplant (liver vs liver-lung), pancreatic insufficiency status, body mass index (BMI) percentile, genotype, and prevalence of diabetes were comparable in those with and without explant steatosis. More than half of allograft biopsies showed significant steatosis (17/31, 54.8%) and lobular inflammation (16/31, 51.6%). Hepatocyte ballooning was less frequent (5/31, 16.1%). Overall, 6 patients (46.2%) had allograft steatosis that worsened over time in 2 patients (33%). None had advanced fibrosis (≥stage 3). Patients with allograft steatosis had significantly more biopsies, were more likely to be "liver only" recipients, had a shorter interval since transplant and higher body mass index percentile (although <85). Patients without explant steatosis never demonstrated allograft steatosis, whereas 60% of patients with explant steatosis (n = 6) developed varying degrees of allograft steatosis. The degree of explant steatosis did not predict its severity in allografts (P = 0.3).

CONCLUSION

This is the first study highlighting the development of allograft steatosis in CF patients. Our findings suggest that allograft steatosis in patients with CF may be related to pre-existing steatosis in native livers, regardless of other risk factors and may have implications on patient management and long-term graft/patient survival.

MicroRNA Sequencing Identifies a Serum MicroRNA Panel, Which Combined With Aspartate Aminotransferase to Platelet Ratio Index Can Detect and Monitor Liver Disease in Pediatric Cystic Fibrosis

Cystic fibrosis (CF)-associated liver disease (CFLD) is a hepatobiliary complication of CF. Current diagnostic modalities rely on nonspecific assessments, whereas liver biopsy is the gold standard to assess severity of fibrosis. MicroRNAs (miRNAs) regulate liver disease pathogenesis and are proposed as diagnostic biomarkers. We investigated the combined use of serum miRNAs and aspartate aminotransferase (AST) to platelet ratio (APRI) to diagnose and assess CFLD severity. This was a cross-sectional cohort study of the circulatory miRNA signature of 124 children grouped by clinical, biochemical, and imaging assessments as follows: CFLD (n = 44), CF patients with no evidence of liver disease (CFnoLD; n = 40), and healthy controls (n = 40). Serum miRNAs were analyzed using miRNA sequencing (miRNA-Seq). Selected differentially expressed serum miRNA candidates were further validated by qRT-PCR and statistical analysis performed to evaluate utility to predict CFLD and fibrosis severity validated by liver biopsy, alone or in combination with APRI. Serum miR-122-5p, miR-365a-3p, and miR-34a-5p levels were elevated in CFLD compared to CFnoLD, whereas miR-142-3p and let-7g-5p were down-regulated in CFLD compared to CFnoLD. Logistic regression analysis combining miR-365a-3p, miR-142-3p, and let-7g-5p with APRI showed 21 times greater odds of accurately predicting liver disease in CF with an area under the receiver operating characteristics curve (AUROC) = 0.91 (sensitivity = 83%, specificity = 92%; P < 0.0001). Expression levels of serum miR-18a-5p were correlated with increasing hepatic fibrosis (HF) stage in CFLD (r_s  = 0.56; P < 0.0001), showing good diagnostic accuracy for distinguishing severe (F3-F4) from mild/moderate fibrosis (F0-F2). A unit increase of miR-18a-5p showed a 7-fold increased odds of having severe fibrosis with an AUROC = 0.82 (sensitivity = 93%, specificity = 73%; P = 0.004), indicating its potential to predict fibrosis severity. Conclusion: We identified a distinct circulatory miRNA profile in pediatric CFLD with potential to accurately discriminate liver disease and fibrosis severity in children with CF.

Diet-Induced Dysbiosis and Genetic Background Synergize With Cystic Fibrosis Transmembrane Conductance Regulator Deficiency to Promote Cholangiopathy in Mice

The most typical expression of cystic fibrosis (CF)-related liver disease is a cholangiopathy that can progress to cirrhosis. We aimed to determine the potential impact of environmental and genetic factors on the development of CF-related cholangiopathy in mice. Cystic fibrosis transmembrane conductance regulator (Cftr)^-/- mice and Cftr ^+/+ littermates in a congenic C57BL/6J background were fed a high medium-chain triglyceride (MCT) diet. Liver histopathology, fecal microbiota, intestinal inflammation and barrier function, bile acid homeostasis, and liver transcriptome were analyzed in 3-month-old males. Subsequently, MCT diet was changed for chow with polyethylene glycol (PEG) and the genetic background for a mixed C57BL/6J;129/Ola background (resulting from three backcrosses), to test their effect on phenotype. C57BL/6J Cftr ^-/- mice on an MCT diet developed cholangiopathy features that were associated with dysbiosis, primarily Escherichia coli enrichment, and low-grade intestinal inflammation. Compared with Cftr ^+/+ littermates, they displayed increased intestinal permeability and a lack of secondary bile acids together with a low expression of ileal bile acid transporters. Dietary-induced (chow with PEG) changes in gut microbiota composition largely prevented the development of cholangiopathy in Cftr ^-/- mice. Regardless of Cftr status, mice in a mixed C57BL/6J;129/Ola background developed fatty liver under an MCT diet. The Cftr ^-/- mice in the mixed background showed no cholangiopathy, which was not explained by a difference in gut microbiota or intestinal permeability, compared with congenic mice. Transcriptomic analysis of the liver revealed differential expression, notably of immune-related genes, in mice of the congenic versus mixed background. In conclusion, our findings suggest that CFTR deficiency causes abnormal intestinal permeability, which, combined with diet-induced dysbiosis and immune-related genetic susceptibility, promotes CF-related cholangiopathy.

A sheep model of cystic fibrosis generated by CRISPR/Cas9 disruption of the CFTR gene

Cystic fibrosis (CF) is a genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. The major cause of limited life span in CF patients is progressive lung disease. CF models have been generated in 4 species (mice, rats, ferrets, and pigs) to enhance our understanding of the CF pathogenesis. Sheep may be a particularly relevant animal to model CF in humans due to the similarities in lung anatomy and development in the two species. Here, we describe the generation of a sheep model for CF using CRISPR/Cas9 genome editing and somatic cell nuclear transfer (SCNT) techniques. We generated cells with CFTR gene disruption and used them for production of CFTR-/- and CFTR+/- lambs. The newborn CFTR-/- sheep developed severe disease consistent with CF pathology in humans. Of particular relevance were pancreatic fibrosis, intestinal obstruction, and absence of the vas deferens. Also, substantial liver and gallbladder disease may reflect CF liver disease that is evident in humans. The phenotype of CFTR-/- sheep suggests this large animal model will be a useful resource to advance the development of new CF therapeutics. Moreover, the generation of specific human CF disease-associated mutations in sheep may advance personalized medicine for this common genetic disorder.

Hepatobiliary disease in children and adolescents with cystic fibrosis

OBJECTIVES

The aims of the study were to determine the frequency of hepatobiliary disease in patients with cystic fibrosis and to describe the sociodemographic, clinical, and laboratory profile of these patients.

METHODS

This was a retrospective, descriptive, and analytical study of 55 patients diagnosed with cystic fibrosis, aged between 3 months and 21 years, followed-up from January 2008 to June 2016 in a referral center. Medical records were consulted and sociodemographic, clinical and laboratory data, including hepatobiliary alterations, imaging studies, genetic studies, liver biopsies, and upper digestive endoscopies were registered.

RESULTS

Hepatobiliary disease was diagnosed in 16.4% of the patients and occurred as an initial manifestation of cystic fibrosis in 55.6% of these cases. The diagnosis of hepatopathy occurred before or concomitantly with the diagnosis of cystic fibrosis in 88.9% of the children. All patients with hepatobiliary disease were considered non-white, with a predominance of females (77.8%) and median (IQR) of 54 (27-91) months. Compared with the group without hepatobiliary disease, children with liver disease had a higher frequency of severe mutations identified in the CFTR gene (77.8% vs. 39.6%, p=0.033) and severe pancreatic insufficiency (88.9% vs. 31.6%, p=0.007).

CONCLUSION

The frequency of hepatobiliary disease was high, with a very early diagnosis of the disease and its complications in the studied series. A statistical association was observed between the occurrence of hepatobiliary disease and the presence of pancreatic insufficiency and severe mutations in the CFTR gene. It is emphasized that cystic fibrosis is an important differential diagnosis of liver diseases in childhood.

Assessment of Liver Disease Progression in Cystic Fibrosis Using Transient Elastography

OBJECTIVES

Cystic fibrosis-related liver disease (CFLD) can develop silently in early life and approximately 10% of children with cystic fibrosis (CF) become cirrhotic before adulthood. Clinical, biological, and ultrasound criteria used to define CFLD often reveal liver involvement at an advanced stage. The aim of this retrospective study was to assess the progression of liver stiffness measurement (LSM) in pediatric patients with CF.

METHODS

The change of LSM, expressed as kPa/year and %/year, was measured using transient elastography (Fibroscan) in 82 children with CF (median age: 6.8 years, interquartile range [IQR]: 5.8). Mean time interval between the 2 LSM was 3.5 years.

RESULTS

Median initial liver stiffness was 3.7 kPa (IQR: 1.3), and then progressed by 0.23 kPa/year, that is, 6%/year. The 7 patients who developed CFLD had a higher initial level of alanine aminotransferase (50 [IQR: 15] vs 30 [IQR: 18], P = 0.0001) and presented a more rapid progression of LSM (0.94 vs 0.23 kPa/year, P = 0.02).

CONCLUSIONS

The present study shows that the slope of worsening of liver stiffness is greater in patients who will develop CFLD, suggesting that annual transient elastography may be useful to detect risk of severe liver disease at an earlier stage.