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

Assessment of cystic fibrosis related liver disease in a pediatric cohort

BACKGROUND

Cystic fibrosis (CF) is an autosomal recessive, chronic, potentially lethal genetic disease. CF manifestations are due to mutations in the CF transmembrane receptor transporter (CFTR) gene which codes for a protein (CFTR) that acts as an anion transporter, mainly chlorine, at epithelial cells where it is expressed. Cystic fibrosis related liver disease (CFRLD) includes a spectrum of hepatobiliary manifestations whose diagnosis and follow-up remains a challenge.

METHODS

Cross-sectional, descriptive study from 10 Spanish cystic fibrosis units. Clinical and biochemical data obtained. Patients categorized into 3 groups according to liver involvement based on ESPGHAN 2017 criteria. Liver stiffness assessed by transient elastography (TE) and findings from abdominal ultrasound recorded. Statistics performed using SPSS v25.0.

RESULTS

We obtained hepatic TE data from 155 pediatric CF patients. Forty-four classified as CFRLD, 38 (86%) had CFRLD without cirrhosis and 6 (14%) had cirrhosis. Fourteen patients without CFRLD (12%) had ultrasound abnormalities. Mean liver elastography value (kPa) was 4.7 (3.5-5.3) in non-CFRLD and 6.09 (4.4-6.7) in CFRLD (p=0.01; T Student [T]).

CONCLUSIONS

CFRLD is common in children with CF. Transient elastography is a useful method for diagnosis and follow-up, as higher values of TE are found in patients with CFRLD.

The Aging Patient with Cystic Fibrosis

Cystic fibrosis (CF) is an inherited condition that leads to multiorgan dysfunction, especially in the respiratory, gastrointestinal, and reproductive tracts, with associated conditions including persistent pulmonary infection, liver disease, pancreatic insufficiency, and infertility. Historically, people with CF (pwCF) suffered a shortened lifespan due to complications of the condition, namely respiratory. The emphasis on center-based, multidisciplinary care and the widespread introduction of cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy has resulted in pwCF living longer and healthier lives. Now they may encounter some of the health and social issues associated with growing older, which previously were not a typical experience for this population. In this article, we review relevant health issues for the aging CF population, including complications that arise from the condition itself, issues encountered due to treatment, and general conditions associated with aging that may manifest earlier or differently in pwCF. We discuss the recommendations for screening and treatment of relevant conditions, and considerations for the integration of healthcare professionals across disciplines into the care of this population.

The effect of elexacaftor-tezacaftor-ivacaftor on liver stiffness in children with cystic fibrosis

OBJECTIVES

Cystic fibrosis hepato-biliary involvement (CFHBI) is a common comorbidity in patients with CF and is associated with increased morbidity and mortality. The effect of the new and highly potent CF transmembrane conductance regulator modulator therapy, elexacaftor-tezacaftor-ivacaftor (ETI), on CFHBI, is still unclear. This study aimed to investigate the impact of ETI on liver stiffness in children with CF, as measured using two-dimensional (2D) shear wave elastography (SWE).

METHODS

Twenty-one children with CF were included in this retrospective study at the CF centre, Skåne University Hospital, Lund, Sweden. Twelve children of our cohort had CFHBI; none had advanced CF liver disease. 2D SWE data from annual assessments, clinical data and liver enzymes were analysed.

RESULTS

We found a significant reduction in liver stiffness after starting treatment with ETI in the total cohort. This reduction in liver stiffness could even be seen in children with CFHBI. Liver enzymes were within the normal range in both pre- and post-ETI therapy in the total cohort. In children with CFHBI, a decline in aspartate aminotransferase activity was observed after ETI was initiated. Lung function and lung clearance index improved significantly after ETI treatment commenced.

CONCLUSION

ETI treatment could positively affect CFHBI in children with CF, as demonstrated by reduced liver stiffness during treatment.

Resolution of portal hypertension in a patient with cystic fibrosis after treatment with CFTR modulator: A case report

Portal hypertension (pH) secondary to cystic fibrosis liver disease (CFLD) is the fourth most common cause for mortality (after respiratory/cardiorespiratory, transplant-related, and cancer-related) in adults with cystic fibrosis (CF) and more often occurs in the absence of cirrhosis (i.e. non-cirrhotic pH, NCPH). Here, we describe a patient with NCPH secondary to CFLD, with resolution of pH after starting a cystic fibrosis transmembrane conductance regulator (CFTR) modulator. As demonstrated in this patient, CFTR modulators may provide extra-pulmonary benefits including reversal of NCPH. Long-term use of CFTR modulators could potentially result in reductions in mortality from pH and need for future liver or combined lung-liver transplantation in patients with CFLD.

Current situation of pediatric cystic fibrosis-related liver disease: results of a Spanish nationwide study

BACKGROUND

Cystic fibrosis-related liver disease (CFRLD) is a health problem that can affect as many as 30-40% of cystic fibrosis patients by the age of 12 years. We studied the epidemiology of CFRLD thanks to the first exclusively pediatric CFRLD patient registry to date.

METHODS

Descriptive cross-sectional study. Information from medical records from January 2018 to December 2020 is collected. CFRLD was classified according to the European Society of Paediatric Gastroenterology, Hepatology and Nutrition 2017 criteria.

RESULTS

Data were collected from 168 pediatric patients diagnosed with CFRLD (90.5% liver involvement without cirrhosis and 8.5% multinodular cirrhosis).

CONCLUSION

In this national registry, including exclusively pediatric population, liver disease is diagnosed around 7 years of age. Liver involvement without cirrhosis is the most frequent finding among our patients but about 9% of the patients already had cirrhosis. CFRLD is one of the challenges faced by pediatric gastroenterologists in the future and national registries give us the opportunity to further study and broaden our knowledge.

The Frequency and Potential Implications of HFE Genetic Variants in Children With Cystic Fibrosis

BACKGROUND

Genetic modifiers have been identified that increase the risks of lung disease and other complications, such as diabetes in people with cystic fibrosis (CF). Variants in the hemochromatosis gene (HFE) were reported in a study of adults to be associated with worse lung disease.

OBJECTIVES

To ascertain the frequency of HFE variants, particularly C282Y (c.845G > A) and H63D (c.187C > G) and to determine if they are associated with variations in the onset and early severity of CF lung disease as well as abnormalities in iron status.

DESIGN

We studied with whole genome sequencing and clinical outcome measures in a cohort of 104 children with CF at 5-6 years old who were previously found to show an association between aggregated genetic modifiers and an earlier onset and a more severe lung disease phenotype.

RESULTS

In our cohort, 23% have H63D and 11% have C282Y. Lung function at age 6 years and Pseudomonas aeruginosa infections did not differ by HFE variants, but having C282Y was associated with more pulmonary exacerbations in the first 6 years of life. Three patients have H63D/C282Y genotype, and all showed phenotypic expression of hemochromatosis with abnormal iron indices.

CONCLUSION

Our study revealed that the presence of HFE variant C282Y in people with CF may lead to more severe lung disease manifestations beginning in early childhood. There is a risk of hemochromatosis in CF patients with two HFE variants, and thus they should be followed for evidence of iron overload.

Non-invasive evaluation of steatosis and fibrosis in the liver in adults patients living with cystic fibrosis

BACKGROUND & AIMS

Cystic fibrosis hepatobiliary involvement is a heterogeneous and systemic entity. The primary objective was to determine the prevalence of steatosis, by magnetic resonance-proton density fat fraction (MR-PDFF), and liver fibrosis, by magnetic resonance elastography (MRE), in a cohort of adults with cystic fibrosis. The secondary objective was to determine the diagnostic yield of widely available non-invasive liver markers for steatosis and fibrosis, and vibration controlled transitional elastography (VCTE) releasing Control Attenuation Parameter (CAP) (dB/m) and stiffness (kPa), with the aim of proposing a diagnostic algorithm.

METHODS

We conducted a cross-sectional study including 101 adult patients with cystic fibrosis seen in a multidisciplinary unit. The study encompassed a clinical evaluation, morpho-functional assessment, VCTE, non-invasive liver markers and MR-PDFF and MRE. Diagnostic accuracy was assessed using ROC curves and 2 × 2 tables.

RESULTS

MR-PDFF detected hepatic steatosis in 18 of 101 (17.8 %) patients, while MRE detected significant liver fibrosis in 15 of 101 (14.9 %). The VCTE cut-off with the best diagnostic yield, determined by the Youden index, was 222 dB/m for the presence of steatosis (AUC 0.864 (95 % CI 0.768-0.961; p < 0.001) and the VCTE cut-off was 6.65 kPa for liver fibrosis (AUC 0.951(95 % CI 0.81-1; p = 0.053). A screening algorithm for hepatic steatosis was developed using the fatty liver index (FLI) and CAP, with a negative predictive value of 83.3 %. For liver fibrosis, it was outperformed by the Hepamet Fibrosis Score (HFS) and VCTE, with a negative predictive value of 100 %.

CONCLUSIONS

The prevalence of hepatic steatosis and liver fibrosis was 17.8 % and 14.9 %, respectively. VCTE alone or in combination with FLI for steatosis or HFS for fibrosis demonstrated high diagnostic accuracy. This approach effectively allows for the exclusion of steatosis and fibrosis, thereby reducing the need for MR-PDFF and MRE studies.

Personalized therapy with CFTR modulators: Response of p.Ile148Asn variant

BACKGROUND

Elucidating the molecular and cellular effects caused by CFTR variants is crucial to understand Cystic Fibrosis (CF) disease pathophysiology, but also to predict disease severity, to provide genetic counselling, and to determine the most adequate therapeutic strategy for people with CF (pwCF). While the current CFTR modulator drugs (CFTRm) are approved mainly for pwCF with the most prevalent variant, p.Phe508del, pwCF carrying rare and/or uncharacterized CFTR variants are not eligible. However, previous studies have shown that such rare variants can be rescued by the approved CFTRm, suggesting clinical benefit for those pwCF. Here, we characterized the rare and non-eligible p.Ile148Asn CFTR variant found in Portuguese pwCF, regarding CFTR processing, traffic and function, and response to existing CFTRm.

METHODS

We used the forskolin-induced swelling (FIS) assay in intestinal organoids (IOs) from 2 CF individuals carrying p.Ile148Asn in heterozygosity with p.Phe508del and p.Gly542Ter, respectively. Additionally, a Cystic Fibrosis Bronchial Epithelial (CFBE) cell line expressing p.Ile148Asn-CFTR was generated to study the molecular defect of this variant individually.

RESULTS

Our results show that p.Ile148Asn is a CF-causing variant, impairing both CFTR plasma membrane (PM) traffic and function, albeit partially. Moreover, p.Ile148Asn-CFTR can be rescued by approved CFTRm in CFBE cells and IOs, suggesting potential clinical benefit for these individuals.

CONCLUSION

The work emphasizes the importance of testing CFTRm for rare variants not included in the drug label. It also shows that the 'theranostic' approach using IOs from pwCF, which captures the genetic background of each individual, complements theratyping in cell lines that focuses only on CFTR variants.

Integration of Non-invasive Screening for Cystic Fibrosis Related Liver Disease in the Regular Follow-Up for Cystic Fibrosis

BACKGROUND

The reported prevalence of cystic fibrosis (CF)-related liver disease (CFLD) reaches up to 40% in some cohorts. CFLD is the 3rd leading cause of mortality among patients with CF. The aims of this study were to evaluate the prevalence of CFLD in a cohort followed at a tertiary university center, to define the types of liver involvement, and to determine how non-invasive screening methods can be optimally integrated into clinical practice.

METHODS

The files of patients followed at the CF clinic of the Centre hospitalier de l'Université de Montréal (CHUM) between 2020 and 2022 were retrospectively reviewed. The NIH criteria were used to define CFLD through the presence of one major criterion (abnormal imaging) or two minor criteria (persistently abnormal laboratory values, hepatosplenomegaly, or transient elastography (TE) ≥ 7 kPa).

RESULTS

A total of 357 patients were included in this study. CFLD was observed in 46 patients (13%). Among these, major criteria led to diagnosis in 43 patients (with or without minor criteria). TE performed best in non-invasive assessment of CLFD (area under the curve (AUROC) 0.80 (0.68-0.92, p = 0.0007)). A nodular liver was detected in 27 patients (7%), and was associated with higher non-invasive markers of fibrosis. In addition, presence of a nodular liver was associated with significant short-term mortality (14.8% vs. 1.5%, p = 0.003).

CONCLUSION

Early recognition of CFLD in clinical care can potentially prevent complications of cirrhosis and portal hypertension. The use of abdominal imaging and TE seems promising for detecting CFLD.

Outcomes of a cross-sectional ultrasound- based study of cystic fibrosis related liver disease: A real world experience

AIMS

To study the prevalence of cystic fibrosis related liver disease (CFLD) as defined by ultrasound (US) and describe difference in clinical and radiological features in those with CFLD and those without CFLD (nCFLD); with and without portal hypertension (PHT and nPHT).

METHODS

Children with CF (CwCF) from our clinic who had regular screening liver US from 3 years of age were included. Liver parenchyma findings were classified into normal, homogeneous, heterogeneous and nodular. For our study, we defined PHT as US evidence of splenomegaly and/or ascites, abnormal portal flow, varices, ligamentum teres recanalization if present. Demographic, clinical, nutritional and lung function between the two groups-CFLD/nCFLD; and subgroups- PHT and nPHT were compared. Gamma glutamyl transferase (GGT)/ platelet ratio (GPR) as a marker of fibrosis was measured.

RESULTS

From 227 CwCF,40 (17 %) were excluded (below the age of 3 years or alternative cause of liver disease). Of the remaining 187, 107 (57 %) had a normal US, 80 (43 %) had CFLD; 25 (13.4 %) had PHT. There was no significant difference in demographics, BMI-z score, lung function, presence of gastrostomy or pancreatic insufficiency in CFLD vs nCFLD and PHT vs nPHT. CF related diabetes mellitus (CFRD) was significantly associated with CFLD vs nCFLD (P = 0.0086). GGT was higher and platelet count was lower in PHT vs nPHT (P = 0.0256 and P = 0.0001). Nodularity was strongly associated with an elevated GPR (P = 0.016). There was a strong association between nodularity on US and PHT (P = 0.0006).

CONCLUSION

Nodularity is a clear marker for advanced liver disease with higher scores for a non-invasive marker for fibrosis. There was no difference in nutrition and FEV1 between advanced liver disease and absent/ milder liver disease.

The ageing of people living with cystic fibrosis: what to expect now?

The prognosis of people with cystic fibrosis (pwCF) has improved dramatically with the introduction of cystic fibrosis transmembrane conductance regulator (CFTR) modulators (CFTRm). The ageing of the cystic fibrosis (CF) population is changing the disease landscape with the emergence of different needs and increasing comorbidities related to both age and long-term exposure to multiple treatments including CFTRm. Although the number of pwCF eligible for this treatment is expected to increase, major disparities in care and outcomes still exist in this population. Moreover, the long-term impact of the use of CFTRm is still partly unknown due to the current short follow-up and experience with their use, thus generating some uncertainties. The future spread and initiation of these drugs at an earlier stage of the disease is expected to reduce the systemic burden of systemic inflammation and its consequences on health. However, the prolonged life expectancy is accompanied by an increasing burden of age-related comorbidities, especially in the context of chronic disease. The clinical manifestations of the comorbidities directly or indirectly associated with CFTR dysfunction are changing, along with the disease dynamics and outcomes. Current protocols used to monitor slow disease progression will need continuous updates, including the composition of the multidisciplinary team for CF care, with a greater focus on the needs of the adult population.

Porto-Sinusoidal Vascular Disease: A New Nomenclature Different from Idiopathic Non-Cirrhotic Portal Hypertension

BACKGROUND AND AIMS

Porto-sinusoidal vascular disease (PSVD) as a novel clinical conception was modified on the basis of idiopathic non-cirrhotic portal hypertension (INCPH). This study aimed to compare the clinical, biochemical histological features and prognosis between the diagnostic criteria for PSVD and that of INCPH.

METHODS

A total of 65 patients who underwent liver biopsies were analyzed retrospectively. The clinical, pathological and prognosis date were reviewed and screened according to the latest diagnostic criteria of PSVD and INCPH.

RESULTS

A total of 65 patients were diagnosed with PSVD, of which 31 (47.69%) also fulfilled INCPH criteria. Specific histological and specific clinical portal hypertension (PH) signs were found in 34 (52.31%) and 30 (46.15%) of the patients, respectively. PSVD patients showed higher LSM levels (11.45 (6.38, 18.08) vs. 7.90 (6.70, 13.00), p = 0.039) than the INCPH patients. INCPH patients had a higher cumulative incidence of liver-related complications than the PSVD patients (86.95% vs. 35.71%, log-rank p < 0.001).

CONCLUSION

Novel PSVD criteria facilitate early diagnosis. PSVD patients with other liver diseases may have higher LSM values. Disease progression and survival outcomes are correlated with PH in PSVD patients.

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.

Genetic engineering drives the breakthrough of pig models in liver disease research

Compared with the widely used rodents, pigs are anatomically, physiologically, and genetically more similar to humans, making them high-quality models for the study of liver diseases. Here, we review the latest research progress on pigs as a model of human liver disease, including methods for establishing them and their advantages in studying cystic fibrosis liver disease, acute liver failure, liver regeneration, non-alcoholic fatty liver disease, liver tumors, and xenotransplantation. We also emphasize the importance of genetic engineering techniques, mainly the CRISPR/Cas9 system, which has greatly enhanced the utility of porcine models as a tool for substantially advancing liver disease research. Genetic engineering is expected to propel the pig as one of the irreplaceable animal models for future biomedical research.

Prominent role of gut dysbiosis in the pathogenesis of cystic fibrosis-related liver disease in mice

BACKGROUND & AIMS

Cystic fibrosis-related liver disease (CFLD) is a chronic cholangiopathy that increases morbidity and mortality in patients with CF. Current treatments are unsatisfactory, and incomplete understanding of CFLD pathogenesis hampers therapeutic development. We have previously shown that mouse CF cholangiocytes respond to lipopolysaccharide with excessive inflammation. Thus, we investigated the role of the gut-liver axis in the pathogenesis of CFLD.

METHODS

Wild-type (WT), whole-body Cftr knockout (CFTR-KO) and gut-corrected (CFTR-KO-GC) mice were studied. Liver changes were assessed by immunohistochemistry and single-cell transcriptomics (single-cell RNA sequencing), inflammatory mediators were analysed by proteome array, faecal microbiota by 16S ribosomal RNA sequencing and gut permeability by FITC-dextran assay.

RESULTS

The livers of CFTR-KO mice showed ductular proliferation and periportal inflammation, whereas livers of CFTR-KO-GC mice had no evident pathology. Single-cell RNA sequencing analysis of periportal cells showed increased presence of neutrophils, macrophages and T cells, and activation of pro-inflammatory and pathogen-mediated immune pathways in CFTR-KO livers, consistent with a response to gut-derived stimuli. CFTR-KO mice exhibited gut dysbiosis with enrichment of Enterobacteriaceae and Enterococcus spp., which was associated with increased intestinal permeability and mucosal inflammation, whereas gut dysbiosis and inflammation were absent in CFTR-KO-GC mice. Treatment with nonabsorbable antibiotics ameliorated intestinal permeability and liver inflammation in CFTR-KO mice. Faecal microbiota transfer from CFTR-KO to germ-free WT mice did not result in dysbiosis nor liver pathology, indicating that defective intestinal CFTR is required to maintain dysbiosis.

CONCLUSION

Defective CFTR in the gut sustains a pathogenic microbiota, creates an inflammatory milieu, and alters intestinal permeability. These changes are necessary for the development of cholangiopathy. Restoring CFTR in the intestine or modulating the microbiota could be a promising strategy to prevent or attenuate liver disease.

IMPACT AND IMPLICATIONS

Severe cystic fibrosis-related liver disease (CFLD) affects 10% of patients with cystic fibrosis (CF) and contributes to increased morbidity and mortality. Treatment options remain limited due to a lack of understanding of disease pathophysiology. The cystic fibrosis transmembrane conductance regulator (CFTR) mediates Cl- and HCO3- secretion in the biliary epithelium and its defective function is thought to cause cholestasis and excessive inflammatory responses in CF. However, our study in Cftr-knockout mice demonstrates that microbial dysbiosis, combined with increased intestinal permeability caused by defective CFTR in the intestinal mucosa, acts as a necessary co-factor for the development of CFLD-like liver pathology in mice. These findings uncover a major role for the gut microbiota in CFLD pathogenesis and call for further investigation and clinical validation to develop targeted therapeutic strategies acting on the gut-liver axis in CF.

Biliary fibrosis is an important but neglected pathological feature in hepatobiliary disorders: from molecular mechanisms to clinical implications

Fibrosis resulting from pathological repair secondary to recurrent or persistent tissue damage often leads to organ failure and mortality. Biliary fibrosis is a crucial but easily neglected pathological feature in hepatobiliary disorders, which may promote the development and progression of benign and malignant biliary diseases through pathological healing mechanisms secondary to biliary tract injuries. Elucidating the etiology and pathogenesis of biliary fibrosis is beneficial to the prevention and treatment of biliary diseases. In this review, we emphasized the importance of biliary fibrosis in cholangiopathies and summarized the clinical manifestations, epidemiology, and aberrant cellular composition involving the biliary ductules, cholangiocytes, immune system, fibroblasts, and the microbiome. We also focused on pivotal signaling pathways and offered insights into ongoing clinical trials and proposing a strategic approach for managing biliary fibrosis-related cholangiopathies. This review will offer a comprehensive perspective on biliary fibrosis and provide an important reference for future mechanism research and innovative therapy to prevent or reverse fibrosis.

Cystic fibrosis hepatobiliary involvement: an update on imaging in diagnosis and monitoring

Analysis of the liver using imaging for persons with cystic fibrosis (CF) continues to evolve as new medical therapies are developed improving and extending life. In the 2010s, therapies targeted at modulating protein folding became available to those with CF. Therapeutic options have continued to expand, now providing both correction of protein folding and stabilization for most gene mutations that code for the CF transmembrane receptor protein (CFTR). Today, approximately 80% of persons with CF are eligible for highly effective modulator therapy. With these advancements, the impact of CF on the liver has become more complex, adding metabolism of CFTR modulators to intrinsic CF hepatobiliary involvement (CFHBI) and adding not previously appreciated vascular changes within the liver due to increased longevity in persons with CF. A combination of serum biomarkers and imaging is needed to add clarity to the diagnosis and monitoring of the severity of liver disease. A substantial portion of persons with CF will develop at least CFHBI and a subset will develop advanced cystic fibrosis-associated liver disease (aCFLD); therefore, diagnosis and monitoring need to begin in childhood. In this review, we cover the use of and need for imaging, including elastography, ultrasound, and magnetic resonance imaging (MRI), in diagnosing and monitoring CFHBI and its associated complications.

Case Series: Hyperbilirubinemia under elexacaftor/tezacaftor/ivacaftor in the presence of Gilbert's syndrome

Liver-related side effects are a known complication of treatment with elexacaftor/tezacaftor/ivacaftor (ETI) for cystic fibrosis (CF). Gilbert's syndrome is caused by a genetic mutation that reduces activity of the enzyme UDP glucuronosyltransferase 1 polypeptide A1 (UGT1A1), causing elevated levels of unconjugated bilirubin in the blood and duodenal bile. The presence of Gilbert's syndrome and CF might represent additive risk factors for liver-related adverse events during ETI treatment. This case series describes six people with CF (pwCF) in whom previously unknown Gilbert's syndrome was unmasked after initiation of treatment with ETI. Although all patients had some level of hepatic dysfunction and/or elevated levels of bilirubin after initiation of ETI, the clinical course varied. Only one patient had to stop ETI therapy altogether, while the others were able to continue treatment (some at a reduced dosage and others at the full recommended daily dosage). All patients, even those using a lower dosage, experienced clinical benefit during ETI therapy. Gilbert's syndrome is not a contraindication for ETI therapy but may be mistaken for a risk factor for liver-related adverse events in pwCF. This is something that physicians need to be aware of in pwCF who show liver adverse events during ETI therapy.

Cystic fibrosis liver disease in the new era of cystic fibrosis transmembrane conductance regulator (CFTR) modulators

Cystic fibrosis liver disease (CFLD) is characterised by a wide heterogenity of manifestations and severity. It represents a major cause of morbidity in people with cystic fibrosis (PwCF), which will be of increasing relevance as survival increases in the new era of cystic fibrosis care. No medical therapy currently available has evidence to treat or prevent progression of liver disease. Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulators may be transformative on pulmonary, nutritional and quality of life, but direct effect on long term liver disease outcomes is not yet established. Drug-associated hepatic adverse effects may be common, and clinician familiarity with drug-monitoring recommendations is essential. Longitudinal studies are required to understand the effect of CFTR modulators on the incidence and natural history of CFLD, including with early treatment initiation, in established advanced liver disease, and post liver transplantation.

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.

Cystic fibrosis management in pediatric population-from clinical features to personalized therapy

Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations of the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR). In 1949, it's been identified as a monogenic disease and was thought to primarily affect individuals of Northern European descent. It was the most prevalent autosomal recessive disease that shortens life. With the availability of multiple testing methodologies nowadays, there is a chance to create novel and enhanced treatment options. Even in the absence of a high sweat chloride test (SCT) result, the discovery of two causal mutations is diagnostic for cystic fibrosis (CF). For a CF diagnosis, however, at least two positive E sweat chloride tests are still required. In order to achieve early and active intervention to manage cystic fibrosis (CF) and its comorbidities, treatment regimens for pediatric patients should be evaluated, improved, and closely monitored. New developments in the treatment of cystic fibrosis (CF) have led to the development of medications derived from molecules that target the pathogenetic pathway of the illness. These options are very efficient and allow pediatric patients to receive individualized care. However, in order to better direct patient care and enhance patient outcomes, it is crucial to research uncommon CF mutations, which can provide crucial information about the prognosis of the disease and the relationships between genotype and phenotype. To ensure the success of creating novel, safer, and more efficient treatment approaches, a deeper understanding of the pathogeny of the illness is required. In the age of customized medicine, genetic research will be essential to improving patient care and quality of life for those with uncommon mutations.

Addressing long-term mortality risk in patients undergoing total pancreatectomy with islet autotransplant (TPIAT): causes of death and risk factors

BACKGROUND

Total pancreatectomy with islet autotransplant (TPIAT) can improve quality of life for individuals with pancreatitis but creates health risks including diabetes, exocrine insufficiency, altered intestinal anatomy and function, and asplenia.

METHODS

We studied survival and causes of death for 693 patients who underwent TPIAT between 2001 and 2020, using the National Death Index with medical records to ascertain survival after TPIAT, causes of mortality, and risk factors for death. We used Kaplan Meier curves to examine overall survival, and Cox regression and competing-risks methods to determine pre-TPIAT factors associated with all-cause and cause-specific post-TPIAT mortality.

RESULTS

Mean age at TPIAT was 33.6 years (SD = 15.1). Overall survival was 93.1% (95% CI 91.2, 95.1%) 5 years after surgery, 85.2% (95% CI 82.0, 88.6%) at 10 years, and 76.2% (95% CI 70.8, 82.3%) at 15 years. Fifty-three of 89 deaths were possibly related to TPIAT; causes included chronic gastrointestinal complications, malnutrition, diabetes, liver failure, and infection/sepsis. In multivariable models, younger age, longer disease duration, and more recent TPIAT were associated with lower mortality.

CONCLUSIONS

For patients undergoing TPIAT to treat painful pancreatitis, careful long-term management of comorbidities introduced by TPIAT may reduce risk for common causes of mortality.

Management of liver disease and portal hypertension in cystic fibrosis: a review

INTRODUCTION

Cystic fibrosis (CF)-associated liver disease can significantly affect the quality of life and survival of people with CF. The hepatobiliary manifestations in CF are various, with focal/multilobular biliary cirrhosis more common in children and porto-sinusoidal vascular disease (PSVD) in young adults. Portal hypertensive complications, particularly bleeding from esophagogastric varices and hypersplenism are common, while liver failure is rarer and mainly linked to biliary disease.

AREAS COVERED

This review explores current therapeutic options for CF-associated liver disease, presenting ongoing studies and new insights into parthenogenesis for potential future therapies.

EXPERT OPINION

Monitoring for signs of portal hypertension is essential. Limited evidence supports ursodeoxycholic acid (UDCA) efficacy in halting CF liver disease progression. The effect of cystic fibrosis transmembrane conductance regulator (CFTR) modulators on liver outcomes lacks definitive data, since patients with CF-related liver disease were excluded from trials due to potential hepatotoxicity. A proposed approach involves using UDCA and modulators in early stages, along with anti-inflammatory agents, with further therapeutic strategies awaiting randomized trials. Prevention of portal hypertensive bleeding includes endoscopic sclerotherapy or ligation of esophageal varices. Nonselective beta-blockers may also prevent bleeding and could be cautiously implemented. Other non-etiological treatments require investigation.

Case Report: When cystic fibrosis, elexacaftor/tezacaftor/ivacaftor therapy, and alpha1 antitrypsin deficiency get together

In the last 10 years, the care of patients with cystic fibrosis (CF) has been revolutionized with the introduction of cystic fibrosis transmembrane conductance regulator (CFTR) modulator drugs, with a major impact on symptoms and life expectancy, especially considering the newest and highly effective elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) therapy. Conversely, adverse effects are relatively frequent, with some being life-threatening, such as severe hepatitis. Clinical trials on children starting CFTR modulators have reported transaminase elevations >3× upper limit of the norm in 10%-20% of patients, whereas real-life studies have reported discontinuation rates three times higher than those observed in phase 3 trials. We report the case of a 10-year-old boy with CF who developed severe acute hepatitis 2 weeks after starting ELX/TEZ/IVA therapy. An extensive screening for potential causes led to the identification of heterozygous alpha1-antitrypsin (AAT) deficiency with genotype MZ. The Z allele of SERPINA1 gene, encoding AAT, is known as a risk factor for CF liver disease. We hypothesized that it may act as a risk factor for drug-induced liver injury from CFTR modulators, notably ELX/TEZ/IVA. Therefore, checking AAT before starting CFTR modulator therapy can be suggested, in particular for children with previous, even transient, liver disease.

Cystic fibrosis and fat malabsorption: Pathophysiology of the cystic fibrosis gastrointestinal tract and the impact of highly effective CFTR modulator therapy

Cystic fibrosis (CF) is a progressive, genetic, multi-organ disease affecting the respiratory, digestive, endocrine, and reproductive systems. CF can affect any aspect of the gastrointestinal (GI) tract, including the esophagus, stomach, small intestine, colon, pancreas, liver, and gall bladder. GI pathophysiology associated with CF results from CF membrane conductance regulator (CFTR) dysfunction. The majority of people with CF (pwCF) experience exocrine pancreatic insufficiency resulting in malabsorption of nutrients and malnutrition. Additionally, other factors can cause or worsen fat malabsorption, including the potential for short gut syndrome with a history of meconium ileus, hepatobiliary diseases, and disrupted intraluminal factors, such as inadequate bile salts, abnormal pH, intestinal microbiome changes, and small intestinal bacterial overgrowth. Signs and symptoms associated with fat malabsorption, such as abdominal pain, bloating, malodorous flatus, gastroesophageal reflux, nausea, anorexia, steatorrhea, constipation, and distal intestinal obstruction syndrome, are seen in pwCF despite the use of pancreatic enzyme replacement therapy. Given the association of poor nutrition status with lung function decline and increased mortality, aggressive nutrition support is essential in CF care to optimize growth in children and to achieve and maintain a healthy body mass index in adults. The introduction of highly effective CFTR modulator therapy and other advances in CF care have profoundly changed the course of CF management. However, GI symptoms in some pwCF may persist. The use of current knowledge of the pathophysiology of the CF GI tract as well as appropriate, individualized management of GI symptoms continue to be integral components of care for pwCF.

Diagnosis, Management, and Prognosis of Cystic Fibrosis-Related Liver Disease in Children

Cystic fibrosis (CF) is a multifaceted disorder predominantly investigated for its pulmonary manifestations, yet patients with CF also exhibit a spectrum of extrapulmonary manifestations, notably those involving the hepatobiliary system. The latter constitutes the third leading cause of morbidity and mortality in individuals with CF. Cystic fibrosis-related liver disease (CFLD), with an escalating prevalence, manifests diverse clinical presentations ranging from hepatomegaly to cirrhosis and hepatopulmonary syndrome. Consequently, early detection and appropriate management are imperative for sustaining the health and influencing the quality of life of CF patients afflicted with CFLD. This review aims to consolidate existing knowledge by providing a comprehensive overview of hepatobiliary manifestations associated with CF. It delineates the clinical hepatobiliary manifestations, diagnostic methodologies, incorporating minimally invasive markers, and therapeutic approaches, encompassing the impact of novel CFTR modulators on CFLD. Given the exigency of early diagnosis and the intricate management of CFLD, a multidisciplinary team approach is essential to optimize care and enhance the quality of life for this subset of patients. In conclusion, recognizing CF as more than solely a pulmonary ailment, the authors underscore the imperative for further clinical investigations to establish a more robust evidence base for CFLD management within the continuum of this chronic disease.

Respiratory problems associated with liver disease in children

Respiratory manifestations of chronic liver disease have a profound impact on patient clinical outcomes. Certain conditions within paediatric liver disease have an associated respiratory pathology. This overlap between liver and respiratory manifestations can result in complex challenges when managing patients and requires clinicians to be able to recognise when referral to specialists is required. While liver transplantation is at the centre of treatment, it opens up further potential for respiratory complications. It is established that these complications place patients at risk of longer stays in hospital and reduced survival. Additionally, late post-transplant complications can occur, including post-transplant lymphoproliferative disease and immunosuppression-induced interstitial lung disease. Although rare, it is important for clinicians to recognise these conditions to allow for prompt management. Finally, as liver disease progresses in children, respiratory complications can occur. Hepatopulmonary syndrome can occur in the context of portal hypertension, resulting in increased mortality and poorer quality of life for patients. Another consequence is portopulmonary hypertension, which can be associated with poor survival. Failure to recognise these complications in children may result in poorer outcomes and therefore it is vital that clinicians can establish when referral to a paediatric respiratory medicine specialist is required.

Small molecule modulators of cystic fibrosis transmembrane conductance regulator (CFTR): Structure, classification, and mechanisms

The advent of small molecule modulators targeting the cystic fibrosis transmembrane conductance regulator (CFTR) has revolutionized the treatment of persons with cystic fibrosis (CF) (pwCF). Presently, these small molecule CFTR modulators have gained approval for usage in approximately 90 % of adult pwCF. Ongoing drug development endeavors are focused on optimizing the therapeutic benefits while mitigating potential adverse effects associated with this treatment approach. Based on their mode of interaction with CFTR, these drugs can be classified into two distinct categories: specific CFTR modulators and non-specific CFTR modulators. Specific CFTR modulators encompass potentiators and correctors, whereas non-specific CFTR modulators encompass activators, proteostasis modulators, stabilizers, reader-through agents, and amplifiers. Currently, four small molecule modulators, all classified as potentiators and correctors, have obtained marketing approval. Furthermore, numerous novel small molecule modulators, exhibiting diverse mechanisms of action, are currently undergoing development. This review aims to explore the classification, mechanisms of action, molecular structures, developmental processes, and interrelationships among small molecule CFTR modulators.

Liver magnetic resonance elastography and fat fraction in pediatric patients with cystic fibrosis versus healthy children

BACKGROUND

Liver involvement is an important cause of morbidity and mortality in patients with cystic fibrosis (CF). While liver biopsy is the gold standard for demonstrating involvement, its invasiveness prompts a search for noninvasive alternatives.

OBJECTIVE

To evaluate liver involvement in pediatric patients with CF (versus healthy controls) using magnetic resonance (MR) elastography/spectroscopy and to correlate the imaging findings with clinical/laboratory characteristics.

MATERIALS AND METHODS

This was a single-center, prospective cross-sectional study conducted between April 2020 and March 2022 in patients with CF versus healthy controls. Patients with CF were divided into two subgroups: those with CF-related liver disease and those without. MR images were acquired on a 1.5-tesla machine. Kilopascal (kPa) values were derived from processing MR elastography images. MR spectroscopy was used to measure liver fat fraction, as an indication of hepatosteatosis. Groups were compared using either the Student's t test or the Mann‒Whitney U test. The chi-square test or Fisher's exact test were used to compare qualitative variables.

RESULTS

Fifty-one patients with CF (12 ± 3.3 years, 32 boys) and 24 healthy volunteers (11.1 ± 2.4 years, 15 boys) were included in the study. Median liver stiffness (P=0.003) and fat fraction (P=0.03) were higher in the CF patients than in the controls. Median liver stiffness values were higher in CF patients with CF-related liver disease than in those without CF-related liver disease (P=0.002). Liver stiffness values of CF patients with high alanine aminotransferase (ALT), high gamma-glutamyl transferase, and thrombocytopenia were found to be higher than those without (P=0.004, P<0.001, P<0.001, respectively). Only the high ALT group showed a high fat fraction (P=0.002).

CONCLUSIONS

Patients with CF had higher liver stiffness than the control group, and patients with CF-related liver disease had higher liver stiffness than both the CF patients without CF-related liver disease and the control group. Patients with CF had a higher fat fraction than the control group. Noninvasive assessment of liver involvement using MR elastography/spectroscopy can support the diagnosis of CF-related liver disease and the follow-up of patients with CF.

The Role of Cystic Fibrosis Transmembrane Conductance Regulator Modulators After Liver Transplantation in Persons With Cystic Fibrosis

Despite advances in treatment for cystic fibrosis (CF), liver disease remains a major contributor to morbidity and mortality for persons with CF. Therefore, liver transplantation may be considered in end-stage CF-related liver disease. We present a young patient with CF who underwent solo liver transplantation and has successfully restarted on elexacaftor/tezacaftor/ivacaftor without significant pulmonary or hepatic complications after transplant.

One-step NGS molecular analysis of the CFTR gene on newborn dried blood spots gives a higher diagnostic sensitivity in affected and carrier subjects: A pilot study

BACKGROUND

Cystic fibrosis is the most common hereditary recessive disease with an incidence of about 1:2500/3000. It has long been known that the disease is caused by deleterious mutations in the CFTR gene. Conventionally, the disease is diagnosed in several phases. The analysis of all the possible disease-causing molecular alterations is time consuming and may not lead to a definitive diagnosis in several cases. Consequently, we propose, in this paper, a rapid sequencing method that, in a single procedural asset, reveals the presence of small mutations and also the copy number variants (CNVs) from the DNA extracted from the Guthrie Spot.

MATERIALS AND METHODS

We first sequenced 30 blood spots, then we validated the method on 100 spots that underwent both traditional analyses and this complete NGS sequencing, and lastly, we tested the strategy on patients who normally do not reach the molecular sequencing step because of low level of Immune-Reactive Trypsinogen.

RESULTS

Using this procedure, we identified 97 variants in the CFTR gene of our samples and 6 CNVs. Notably, the significant data were obtained in the group of patients with borderline or negative IRT who routinely would not undergo molecular testing. We also identified 6 carriers of "disease-causing" variants.

CONCLUSION

This method is very robust. Indeed, there was a 100% concordance with Sanger sequencing validation, and 6 mutation carriers were identified who normally escaped molecular testing with actual conventional procedure. There were also 3 duplications of almost the entire gene in heterozygosity, which were not seen with traditional methods. Being quick and easy to perform, we suggest that complete sequencing of the CFTR gene, as in this study be considered for all newborns.

Towards a Standardized Classification of the Hepatobiliary Manifestations in Cystic Fibrosis (CFHBI): A Joint ESPGHAN/NASPGHAN Position Paper

The broad spectrum of hepatobiliary involvement in cystic fibrosis (CF) has been commonly referred to as cystic fibrosis liver disease (CFLD). However, differences in the definitions of CFLD have led to variations in reported prevalence, incidence rates, and standardized recommendations for diagnosis and therapies. Harmonizing the description of the spectrum of hepatobiliary involvement in all people with CF (pwCF) is deemed essential for providing a reliable account of the natural history, which in turn supports the development of meaningful clinical outcomes in patient care and research. Recognizing this necessity, The European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) commissioned and tasked a committee to develop and propose a systematic classification of the CF hepatobiliary manifestations to increase uniformity, accuracy, and comparability for clinical, registry, and research purposes. This report describes the committee's combined expert position statement on hepatobiliary involvement in CF, which has been endorsed by NASPGHAN and ESPGHAN. We recommend using CFHBI (Cystic Fibrosis Hepato-Biliary Involvement) as the updated term to describe and classify all hepatobiliary manifestations in all pwCF. CFHBI encompasses the current extensive spectrum of phenotypical, clinical, or diagnostic expressions of liver involvement observed in pwCF. We present a schematic categorization of CFHBI, which may also be used to track and classify the changes and development of CFHBI in pwCF over time. The proposed classification for CFHBI is based on expert consensus and has not been validated for clinical practice and research purposes. Achieving validation should be an important aim for future research.

The genetics of portal hypertension: Recent developments and the road ahead

Portal hypertension (PH), defined as a pathological increase in the portal vein pressure, has different aetiologies and causes. Intrahepatic PH is mostly secondary to the presence of underlying liver disease leading to cirrhosis, characterized by parenchymal changes with deregulated accumulation of extracellular matrix and vascular abnormalities; liver sinusoidal endothelial cells and hepatic stellate cells are key players in PH progression, able to influence each other. However, PH may also develop independently of parenchymal damage, as occur in portosinusoidal vascular disorder (PSVD), a group of clinical and histological entities characterized by portal vasculature dysfunctions. In this particular group of disorders, the pathophysiology of PH is still poorly understood. In the last years, several genetic studies, based on genome-wide association studies or whole-exome sequencing analysis, have highlighted the importance of genetic heritability in PH pathogenesis, both in cirrhotic and non-cirrhotic cases. The common PNPLA3 p.I148M variant, one of the main determinants of the susceptibility to steatotic liver disease, has also been associated with decompensation in patients with PH. Genetic variations at loci influencing coagulation, mainly the ABO locus, may directly contribute to the pathogenesis of PH. Rare genetic variants have been associated with familiar cases of progressive PSVD. In this review, we summarize the recent knowledges on genetic variants predisposing to PH development, contributing to better understand the role of genetic factors in PH pathogenesis.

[Cystic fibrosis: Epidemiology, clinical manifestations, diagnosis and treatment]

Cystic fibrosis is a genetic and multisystemic disease. The main comorbidity in adulthood is respiratory involvement, with the presence of bronchiectasis, chronic bronchial infection and airflow obstruction. Until a decade ago, treatments were aimed at favoring secretion drainage, reducing respiratory exacerbations, controlling chronic bronchial infection and slowing functional deterioration, but with the advent of cystic fibrosis transmembrane conductance regulator (CFTR) modulators, the cystic fibrosis paradigm has changed. This novel treatment goes a step further in the management of this disease, it is able to improve the production of defective CFTR protein and increase its expression on the cell surface, thus achieving a better functioning of ion exchange, fluidizing respiratory secretions and reducing airflow obstruction. In addition, there are currently different lines of research aimed at correcting the genetic defect that causes cystic fibrosis.

The non-invasive evaluation of liver involvement in patients with cystic fibrosis: A prospective study

BACKGROUND AND AIMS

Porto-sinusoidal vascular disease (PSVD) has been described as the prominent pathology in liver explants of patients with cystic fibrosis (CF), but data outside the transplant setting are lacking. We aimed to investigate the prevalence of portal hypertension (PH) in CF-associated liver disease (CFLD) and develop an algorithm to classify liver involvement in CF patients.

METHODS

This is a cross-sectional study of consecutive paediatric and adult patients in a tertiary centre between 2018 and 2019, who underwent ultrasound, liver (LSM) and spleen stiffness (SSM) measurement. CFLD was defined according to physical examination, liver tests and ultrasound findings. PSVD was likely if there were PH signs in the absence of advanced chronic liver disease (CF-ACLD, LSM <10 kPa). A historical cohort was used to validate the prognostic significance of the new definitions.

RESULTS

Fifty (27.5%) patients met CFLD criteria. At least one sign of PH was found in 47 (26%) patients, but most (81%) had LSM <10 kPa and were likely to have PSVD; only 9 (5%) had CF-ACLD. PSVD and CFLD (LSM <10 kPa) co-existed in most (23/36) cases. In the historical cohort (n = 599 patients), likely PSVD and CFLD+PH were independently associated with a 2-fold and 3.5-fold increase in mortality compared to patients without PH, respectively. In 34 patients with SSM, values <21 and >50 kPa accurately diagnosed specific signs of PH.

CONCLUSIONS

PSVD is the prevailing cause of PH in CF patients. We developed a new diagnostic algorithm based on clinical and elastosonography criteria to classify liver involvement in patients with CF.

Update on Cystic Fibrosis in Pediatric Patients

PURPOSE OF REVIEW

Cystic fibrosis is an inherited, multisystem disease that affects the gastrointestinal system in numerous ways. This article reviews the nutritional, gastrointestinal, and hepatobiliary manifestations of cystic fibrosis with an emphasis on the effects of CFTR modulator therapy.

RECENT FINDINGS

The life expectancy of individuals with cystic fibrosis has increased substantially in recent years. CFTR modulator therapy improves pulmonary function and results in weight gain. An individualized approach to nutrition is encouraged. Pancreatic exocrine function may improve with intervention early in life. The use of non-invasive methods to screen for hepatobiliary involvement is recommended. Highly effective CFTR modulators lead to increased survival and improved quality of life for many individuals. Their effects on gastrointestinal symptoms and hepatobiliary disease are not fully understood. Patient-reported outcome measures and biomarkers are important clinical endpoints for studying the effects of modulators.

Mathematical models of cystic fibrosis as a systemic disease

Cystic fibrosis (CF) is widely known as a disease of the lung, even though it is in truth a systemic disease, whose symptoms typically manifest in gastrointestinal dysfunction first. CF ultimately impairs not only the pancreas and intestine but also the lungs, gonads, liver, kidneys, bones, and the cardiovascular system. It is caused by one of several mutations in the gene of the epithelial ion channel protein CFTR. Intense research and improved antimicrobial treatments during the past eight decades have steadily increased the predicted life expectancy of a person with CF (pwCF) from a few weeks to over 50 years. Moreover, several drugs ameliorating the sequelae of the disease have become available in recent years, and notable treatments of the root cause of the disease have recently generated substantial improvements in health for some but not all pwCF. Yet, numerous fundamental questions remain unanswered. Complicating CF, for instance in the lung, is the fact that the associated insufficient chloride secretion typically perturbs the electrochemical balance across epithelia and, in the airways, leads to the accumulation of thick, viscous mucus and mucus plaques that cannot be cleared effectively and provide a rich breeding ground for a spectrum of bacterial and fungal communities. The subsequent infections often become chronic and respond poorly to antibiotic treatments, with outcomes sometimes only weakly correlated with the drug susceptibility of the target pathogen. Furthermore, in contrast to rapidly resolved acute infections with a single target pathogen, chronic infections commonly involve multi-species bacterial communities, called "infection microbiomes," that develop their own ecological and evolutionary dynamics. It is presently impossible to devise mathematical models of CF in its entirety, but it is feasible to design models for many of the distinct drivers of the disease. Building upon these growing yet isolated modeling efforts, we discuss in the following the feasibility of a multi-scale modeling framework, known as template-and-anchor modeling, that allows the gradual integration of refined sub-models with different granularity. The article first reviews the most important biomedical aspects of CF and subsequently describes mathematical modeling approaches that already exist or have the potential to deepen our understanding of the multitude aspects of the disease and their interrelationships. The conceptual ideas behind the approaches proposed here do not only pertain to CF but are translatable to other systemic diseases. This article is categorized under: Congenital Diseases > Computational Models.

The natural history of cystic fibrosis liver disease a prospective cohort study

BACKGROUND

Our understanding of the natural history of cystic fibrosis liver disease (CFLD) is limited, leading to uncertainty for patients their families and clinicians when liver abnormalities are identified.

AIM

to determine the incidence of CFLD, identify risk factors and document the natural history of liver abnormalities in cystic fibrosis (CF).

METHODS

The Irish longitudinal study of CFLD (ILSCFLD) prospectively enrolled 95% of children with CF in 2007. Their liver disease status was classified as (i) advanced liver disease with portal hypertension (CFLD). (ii) nonspecific cystic fibrosis liver disease (NSCFLD) (iii) no liver disease (NoLD) RESULTS: 480/522 (91.9%) children were followed for a median 8.53 years IQR 1.28, of whom 35 (7.29%) had CFLD, 110 (22.9%) NSCFLD and 335 (69.79%) had NoLD. At follow-up 28/445 (6.29%) participants without CFLD at baseline, progressed to CFLD (Incidence 7.51/1000 person years (Pyrs) (95%CI 4.99-10.86). Of these 25/28(89.28%) were <10 years. No participant >10 years of age without clinical or radiological evidence of liver disease at baseline progressed to CFLD. During follow-up 18/35(51.43%) participants with CFLD died or received a transplant, MTx rate 7.75/100 Pyrs (95%CI 4.59-12.25) compared to NSCFLD 2.33/100 Pyrs (95%CI 1.44-3.56) and NoLD 1.13/100 Pyrs (95%CI 0.77-1.59). CFLD was an independent risk factor for mortality in CF. Children with CFLD also had a shorter life expectancy.

CONCLUSION

The incidence of CFLD was highest in children under10 years. Children over10 years, with normal hepatic function did not develop CFLD. Research to identify the cause and improve outcome should focus on young children.

Cystic fibrosis liver disease in the post-modulator era

PURPOSE OF REVIEW

Highly effective modulators of cystic fibrosis transmembrane conductance regulator (CFTR) function have had dramatic impact on pulmonary and nutritional outcomes in persons with cystic fibrosis (pwCF). The impact on liver disease in pwCF was not the focus of the registration trials. The purpose of this review is to assess the current literature on the impact of HEMT on liver disease, progression, regression, and safety.

RECENT FINDINGS

Short-term studies of HEMT in pwCF have shown that there is no significant impact on the frequency of liver enzyme abnormalities. There is no evidence for significant improvement in liver enzymes over time on HEMT therapy. There is conflicting data on improvement in liver fibrosis determined by fibrosis indices (APRI and GPR) or elastography. One study showed improvement, and another showed worsening in younger (<20 years old) pwCF. There are reports of resolution or improvement in hepatic steatosis. There are rare reports of severe acute hepatitis and one report of hepatic decompensation leading to liver transplantation due to drug-induced liver disease.

SUMMARY

HEMT have not been shown to have a significant impact on improving liver disease or preventing fibrosis with short-term therapy. Longer studies are needed to assess the impact of HEMT on liver disease in pwCF.

Nutritional management of people living with cystic fibrosis throughout life and disease continuum: Changing times, new challenges

Cystic fibrosis (CF) is a genetic disease caused by mutations in the gene encoding for the ion channel cystic fibrosis transmembrane conductance regulator (CFTR). The management of CF disease has evolved in recent decades from treating downstream disease manifestations affecting the airways, the lungs and the gastrointestinal system to addressing the CFTR gene defect. The advent of CFTR modulators, which correct the functionality of the defective CFTR, contributes to reshaping the landscape of CF demographics, prognosis and therapies, including nutritional management. A spectrum of clinical manifestations is emerging within the same patient population where undernutrition and nutritional deficiencies coexist with excessive weight gain and metabolic derangements. Such contrasting presentations challenge current practices, require adjustments to traditional approaches, and involve more individualised interventions. This narrative review examines the current state of knowledge on the nutritional management of people living with cystic fibrosis from early life to adulthood in the era of CFTR modulation.

Systemic Disease and the Liver Part 2: Pregnancy-Related Liver Injury, Sepsis/Critical Illness, Hypoxia, Psoriasis, Scleroderma/Sjogren's Syndrome, Sarcoidosis, Common Variable Immune Deficiency, Cystic Fibrosis, Inflammatory Bowel Disease, and Hematologic Disorders

The liver is involved in many multisystem diseases and commonly may manifest with abnormal liver chemistry tests. The liver test perturbations may be multifactorial in nature, however, as patients are receiving many different medications and can also have intrinsic liver disease that may be exacerbated by the systemic disorder. Some disorders have typical histologic findings that can be diagnosed on liver biopsy, whereas others will show a more nonspecific histology. Clinicians should be aware of these conditions so as to consider the performance of a liver biopsy at the most opportune time and setting to help establish the diagnosis of acute or chronic liver disease.

Recent advances in proteomic-based diagnostics of cystic fibrosis

INTRODUCTION

Cystic fibrosis (CF) is a genetic disease characterized by thick and sticky mucus accumulation, which may harm numerous internal organs. Various variables such as gene modifiers, environmental factors, age of diagnosis, and CF transmembrane conductance regulator (CFTR) gene mutations influence phenotypic disease diversity. Biomarkers that are based on genomic information may not accurately represent the underlying mechanism of the disease as well as its lethal complications. Therefore, recent advancements in mass spectrometry (MS)-based proteomics may provide deep insights into CF mechanisms and cellular functions by examining alterations in the protein expression patterns from various samples of individuals with CF.

AREAS COVERED

We present current developments in MS-based proteomics, its application, and findings in CF. In addition, the future roles of proteomics in finding diagnostic and prognostic novel biomarkers.

EXPERT OPINION

Despite significant advances in MS-based proteomics, extensive research in a large cohort for identifying and validating diagnostic, prognostic, predictive, and therapeutic biomarkers for CF disease is highly needed.

Histological evaluation in biliary diseases

PURPOSE OF REVIEW

This review focuses on recent developments of histopathology in the most common biliary disorders affecting adults. The reader is referred to other sources for the specialized topics on paediatric populations and post liver transplantation.

RECENT FINDINGS

Fibrosis stage at diagnosis is an independent predictor of liver transplant-free survival in patients with primary biliary cholangitis. Immunohistochemistry might have an important role in predicting response to treatment. New histological scoring systems with excellent correlation with long-term clinical outcomes are being developed in primary sclerosing cholangitis (PSC). Quantification of fibrosis with collagen proportionate area can improve risk stratification and could be particularly useful to assess treatment response in PSC.Gene sequencing on cytology and intrabiliary biopsy may improve risk stratification for cholangiocarcinoma. Genetic variants of ATP8B1, ABCB11 and ABCB4 are relatively common in adults with cholestatic liver disease. New causes of cholestatic liver injury have recently been described.

SUMMARY

Histology is often not necessary for the diagnosis of biliary disease, but can provide important information that may assist the clinician in patients' management. Histopathology remains crucial to confirm a diagnosis of cholangiocarcinoma, and to identify the pattern of biliary injury in immune-mediated cholangiopathies and rarer pathological entities.

Cystic fibrosis rabbits develop spontaneous hepatobiliary lesions and CF-associated liver disease (CFLD)-like phenotypes

Cystic fibrosis (CF) is an autosomal recessive genetic disease affecting multiple organs. Approximately 30% CF patients develop CF-related liver disease (CFLD), which is the third most common cause of morbidity and mortality of CF. CFLD is progressive, and many of the severe forms eventually need liver transplantation. The mechanistic studies and therapeutic interventions to CFLD are unfortunately very limited. Utilizing the CRISPR/Cas9 technology, we recently generated CF rabbits by introducing mutations to the rabbit CF transmembrane conductance regulator (CFTR) gene. Here we report the liver phenotypes and mechanistic insights into the liver pathogenesis in these animals. CF rabbits develop spontaneous hepatobiliary lesions and abnormal biliary secretion accompanied with altered bile acid profiles. They exhibit nonalcoholic steatohepatitis (NASH)-like phenotypes, characterized by hepatic inflammation, steatosis, and fibrosis, as well as altered lipid profiles and diminished glycogen storage. Mechanistically, our data reveal that multiple stress-induced metabolic regulators involved in hepatic lipid homeostasis were up-regulated in the livers of CF-rabbits, and that endoplasmic reticulum (ER) stress response mediated through IRE1α-XBP1 axis as well as NF-κB- and JNK-mediated inflammatory responses prevail in CF rabbit livers. These findings show that CF rabbits manifest many CFLD-like phenotypes and suggest targeting hepatic ER stress and inflammatory pathways for potential CFLD treatment.

Immunologic Responses and the Pathophysiology of Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is an autoimmune liver disease with a female predisposition and selective destruction of intrahepatic small bile ducts leading to nonsuppurative destructive cholangitis. It is characterized by seropositivity of antimitochondrial antibodies or PBC-specific antinuclear antibodies, progressive cholestasis, and typical liver histologic manifestations. Destruction of the protective bicarbonate-rich umbrella is attributed to the decreased expression of membrane transporters in biliary epithelial cells (BECs), leading to the accumulation of hydrophobic bile acids and sensitizing BECs to apoptosis. A recent X-wide association study reveals a novel risk locus on the X chromosome, which reiterates the importance of Treg cells.

Prevalence and characteristics of cystic fibrosis liver disease: a study highlighting the lack of histological diagnosis

BACKGROUND AND AIMS

Cystic fibrosis liver disease (CFLD) is the third leading cause of death in patients with cystic fibrosis (CF). We aim to determine the prevalence of CFLD in a cohort of adult patients with CF and to characterise liver involvement in this population highlighting the importance of histological diagnosis.

METHODS

We retrospectively studied a cohort of patients with CF. Inclusion criteria were age ≥ 18 and minimum 1 year of follow-up. We excluded lung transplant patients. CFLD was defined as having 2 out of 3 criteria: persistent elevation of transaminases and/or gamma-glutamyltransferase; abnormal ultrasound; and abnormal transient elastography. Non-invasive fibrosis biomarkers were calculated in CFLD patients. Adult-onset CFLD (Ad-CFLD) was defined as CFLD ≥18 years. Severe CFLD (s-CFLD) was defined as CFLD with cirrhosis and/or portal hypertension.

RESULTS

We included 113 patients. Median age was 29 years, 58 were male. Forty patients had CFLD. Median age at CFLD diagnosis was 10 years. Twenty-one patients had s-CFLD. Two s-CFLD patients had nodular regenerative hyperplasia, 1 had hepatocellular carcinoma and 4 underwent liver transplantation. Six patients had ad-CFLD. Both CFLD and s-CFLD groups were compared to a non-CFLD group. The CFLD group had significantly more males (p = 0.034). S-CFLD group had worse pulmonary function (p = 0.015).

CONCLUSION

Thirty five percent of adult patients with CF, mainly males, had CFLD. Nineteen percent had s-CFLD and had worse pulmonary function. With recent reports unravelling different pathophysiological mechanisms in CFLD, we believe it is important to better characterise liver involvement using liver biopsy.

Novel Substituted Cyclopropyl Compounds as CFTR Modulators for Treating Cystic Fibrosis

Provided herein are novel substituted cyclopropyl compounds as CFTR modulators, pharmaceutical compositions, use of such compounds in treating cystic fibrosis, and processes for preparing such compounds.