Liver disease in patients with cystic fibrosis

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 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.

Potential systemic effects of acquired CFTR dysfunction in COPD

Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation, respiratory symptoms, inflammation of the airways, and systemic manifestations of the disease. Genetic susceptibility and environmental factors are important in the development of the disease, particularly exposure to cigarette smoke which is the most notable risk factor. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene are the cause of cystic fibrosis (CF), which shares several pathophysiological pulmonary features with COPD, including airway obstruction, chronic airway inflammation and bacterial colonization; in addition, both diseases also present systemic defects leading to comorbidities such as pancreatic, gastrointestinal, and bone-related diseases. In patients with COPD, systemic CFTR dysfunction can be acquired by cigarette smoking, inflammation, and infection. This dysfunction is, on average, about half of that found in CF. Herein we review the literature focusing on acquired CFTR dysfunction and the potential role in the pathogenesis of comorbidities associated with COPD and chronic bronchitis.

Delayed identification of compound heterozygous (Phe508del/Arg117His) cystic fibrosis variants in a patient awaiting liver transplantation

A man in his 60s undergoing liver transplant assessment was referred to the respiratory team after a thoracic CT scan revealed diffuse tree-in-bud changes. He had a history of infertility, chronic pancreatitis and liver cirrhosis with portal hypertension. Broncho-alveolar lavage was positive for Pseudomonas aeruginosa Genetic screening found two cystic fibrosis transmembrane conductance regulator variants: Phe508del and Arg117His-7T. The patient was referred to the regional cystic fibrosis (CF) centre for follow-up but died from hepatobiliary complications. The atypical presentation with relatively late onset of pulmonary disease and hepatobiliary disease predominance created a diagnostic challenge. This case is a reminder that while CF is a monogenic disorder, its manifestation, natural history and extent can be highly variable. Taking a thorough medical history of any chronic illness is essential, and patients with the appropriate clinical presentation, regardless of age, should be investigated for CF.

Type II Abernethy malformation with cystic fibrosis in a 12-year-old girl: A case report

BACKGROUND

Abernethy malformation, also known as congenital extrahepatic portosystemic shunt, is an uncommon malformation resulting from aberrant development of the portal venous system. Cystic fibrosis (CF) is an autosomal recessive genetic disease caused by mutations in the CFTR gene. It mainly affects the exocrine glands of the respiratory, digestive and reproductive systems. It is considered extremely rare in the Asian population. We present a clinical case involving a pediatric patient of Asian descent who was diagnosed with Abernethy malformation and CF.

CASE SUMMARY

A 12-year-old girl presented with a medical history of recurring respiratory infections and hemoptysis, and chest computed tomography (CT) showed bronchiectasis. Whole exome sequencing was performed for the patient, yielding findings that revealed a compound heterozygous variant of the CFTR gene: c.233_c.234insT/p.Trp79fsTer3 (maternal origin); c.2909G>A/p.Gly970Asp (paternal origin). CF was diagnosed. The physician’s attention was drawn to the presence of splenomegaly during disease progression. Abdominal enhanced CT revealed splenomegaly, compression of the left kidney, and multiple tortuous dilated vascular shadows were seen at the splenic hilum, which flowed back into the left renal vein and portal vein, suggesting Abernethy malformation type II. Intraoperatively, the abnormal blood flow was seen to merge into the inferior vena cava through the left renal vein without hepatic processing, and the pathology of liver biopsy showed hypoplastic, dilated or absent portal vein branches, both of which supported the diagnosis of Abernethy malformation type II. This represents the initial documented instance of Abernethy malformation accompanied by a CFTR gene mutation in the existing body of literature.

CONCLUSION

Coexisting Abernethy malformation and CF are rare. Detailed medical history information, abdominal enhanced CT, venography and genetic testing contribute to diagnosis as well as differential diagnosis.

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.

Fecal Proteome Profile in Dogs Suffering from Different Hepatobiliary Disorders and Comparison with Controls

In the present study, the fecal proteomes of clinically healthy dogs (HD = n. 10), of dogs showing clinical, ultrasonographic, and/or laboratory evidence of different hepatobiliary dysfunction (DHD = n. 10), and of dogs suffering from chronic hepatitis (CHD = n. 10) were investigated with an Ultimate 3000 nanoUPLC system, coupled to an Orbitrap Fusion Lumos Tribrid mass spectrometer. Fifty-two different proteins of canine origin were identified qualitatively in the three study groups, and quantitative differences were found in 55 proteins when comparing groups. Quantitatively, a total of 41 and 36 proteins were found differentially abundant in the DHD and CHD groups compared to the control HD, and 38 proteins resulted dysregulated in the CHD group as compared to the DHD group. Among the various proteins, differently abundant fecal fibronectin and haptoglobin were more present in the feces of healthy and DHD dogs than in chronic ones, leading us to hypothesize its possible diagnostic/monitoring role in canine chronic hepatitis. On the other hand, the trefoil factor 2 was increased in DHD dogs. Our results show that the analysis of the fecal proteome is a very promising field of study, and in the case of dogs suffering from different hepatobiliary disorders, it was able to highlight both qualitative and quantitative differences among the three groups included. Results need to be confirmed with western blotting and in further studies.

Design of Crotoxin-Based Peptides with Potentiator Activity Targeting the ΔF508NBD1 Cystic Fibrosis Transmembrane Conductance Regulator

We have previously shown that the CBb subunit of crotoxin, a β-neurotoxin with phospholipase A₂ (PLA₂) activity, targets the human ΔF508CFTR chloride channel implicated in cystic fibrosis (CF). By direct binding to the nucleotide binding domain 1 (NBD1) of ΔF508CFTR, this neurotoxic PLA₂ acts as a potentiator increasing chloride channel current and corrects the trafficking defect of misfolded ΔF508CFTR inside the cell. Here, for a therapeutics development of new anti-cystic fibrosis agents, we use a structure-based in silico approach to design peptides mimicking the CBb-ΔF508NBD1 interface. Combining biophysical and electrophysiological methods, we identify several peptides that interact with the ΔF508NBD1 domain and reveal their effects as potentiators on phosphorylated ΔF508CFTR. Moreover, protein-peptide interactions and electrophysiological studies allowed us to identify key residues of ΔF508NBD1 governing the interactions with the novel potentiators. The designed peptides bind to the same region as CBb phospholipase A₂ on ΔF508NBD1 and potentiate chloride channel activity. Certain peptides also show an additive effect towards the clinically approved VX-770 potentiator. The identified CF therapeutics peptides represent a novel class of CFTR potentiators and illustrate a strategy leading to reproducing the effect of specific protein-protein interactions.

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.

Gene Polymorphism of Biotransformation Enzymes and Ciprofloxacin Pharmacokinetics in Pediatric Patients with Cystic Fibrosis

(1) Background: Ciprofloxacin (CPF) is widely used for the treatment of cystic fibrosis, including pediatric patients, but its pharmacokinetics is poorly studied in this population. Optimal CPF dosing in pediatric patients may be affected by gene polymorphism of the enzymes involved in its biotransformation. (2) Materials and Methods: a two-center prospective non-randomized study of CPF pharmacokinetics with sequential enrollment of patients (n-33, mean age 9.03 years, male-33.36%), over a period from 2016 to 2021. All patients received tablets of the original CPF drug Cyprobay® at a dose of 16.5 mg/kg to 28.80 mg/kg. Blood sampling schedule: 0 (before taking the drug), 1.5 h; 3.0 h; 4.5 h; 6.0 h; 7.5 h after the first dosing. CPF serum concentrations were analyzed by high performance liquid chromatography mass spectrometry. The genotype of biotransformation enzymes was studied using total DNA isolated from whole blood leukocytes by the standard method. (4) Results: a possible relationship between the CA genotype of the CYP2C9 gene (c.1075A > C), the GG genotype of the CYP2D6*4 gene (1846G > A), the AG genotype of the GSTP1 gene (c.313A > G), the GCLC* genotype 7/7 and the CPF concentration in plasma (increased value of the area under the concentration−time curve) was established. Conclusions: Gene polymorphism of biotransformation enzymes may affect ciprofloxacin pharmacokinetics in children.

Neutrophil dysfunction in the pathogenesis of cystic fibrosis

Polymorphonuclear neutrophils (PMNs) figure prominently in host defense against infection and in noninfectious inflammation. Mobilized early in an inflammatory response, PMNs mediate immediate cellular defense against microbes and orchestrate events that culminate in cessation of inflammation and restoration of homeostasis. Failure to terminate the inflammatory response and its causes can fuel exuberant inflammation characteristic of many human diseases, including cystic fibrosis (CF), an autosomal recessive genetic disease caused by mutations in the CF transmembrane conductance regulator. CF affects multiple end organs, with persistent bacterial infection and chronic neutrophilic inflammation in airways predominating the clinical picture. To match the diverse microbial challenges that they may encounter, PMNs possess a variety of antimicrobial systems to slow or kill invading microorganisms confined in their phagosomes. Prominent among PMN defense systems is their ability to generate hypochlorous acid, a potent microbicide, by reacting oxidants generated by the NADPH oxidase with myeloperoxidase (MPO) released from azurophilic granules in the presence of chloride (Cl-). Products of the MPO-H2O2-Cl system oxidize susceptible biomolecules and support robust antimicrobial action against many, but not all, potential human pathogens. Underscoring that the MPO-H2O2-Cl system is integral to optimal host defense and proper regulation of inflammation, individuals with defects in any component of this system, as seen in chronic granulomatous disease or MPO deficiency, incur increased rates or severity of infection and signs of dysregulated inflammatory responses. We focus attention in this review on the molecular basis for and the clinical consequences of defects in the MPO-H2O2-Cl system because of the compromised Cl transport seen in CF. We will discuss first how the MPO-H2O2-Cl system in healthy PMNs participates in host defense and resolution of inflammation and then review how a defective MPO-H2O2-Cl system contributes to the increased susceptibility to infection and dysregulated inflammation associated with the clinical manifestations of CF.

Assessment of Liver Fibrosis with the Use of Elastography in Paediatric Patients with Diagnosed Cystic Fibrosis

Background

Complications of cystic fibrosis-associated liver disease (CFLD) are a leading nonpulmonary cause of death. Noninvasive tests enabling early detection of liver changes, especially in children are sought. The aim of the study was to assess the scale of liver fibrosis with the use of elastography in paediatric patients with diagnosed cystic fibrosis (CF) and its comparison with other tests (APRI and Fibrotest).

Methods

We examined 41 children, in the age range 2-21 years, with diagnosed CF. The analysis a included clinical picture, laboratory parameters of liver damage, and cholestasis. Aspartate aminotransferase-to-platelet ratio index (APRI) and Fibrotest were done in all patients. Liver stiffness measurements were acquired using shear-wave elastography (SWE).

Results

CFLD was diagnosed in 16/41 patients (39%). Abnormal elastography was observed in 19/41 patients (46.3%), and in 5/41 (12.2%), the changes were advanced (F4). Abnormal elastography was observed in 12/16 (75%) of the patients with CFLD, and in 7/25 (28%), there were no lesions observed in the liver in the course of cystic fibrosis. In all patients with F4, we observed abnormal results of the APRI and Fibrotest. In most patients with small changes in elastography, we found normal results of the APRI and Fibrotest.

Conclusion

Elastography seems to be a noninvasive examination useful in everyday clinical work in detecting early liver changes and monitoring of progression in paediatric patients with diagnosed cystic fibrosis, ahead of changes in laboratory tests. The cost-effectiveness of this test, the possibility of its repetition, and its availability are additional benefits.

Increasing life expectancy in cystic fibrosis: Advances and challenges

Since the first description of cystic fibrosis in 1938, there have been significant advances in both quality of life and longevity for people living with this disease. In this article we describe the milestones of the last 80 years and what we perceive to be the remaining barriers to normalcy for this population.

The effect of the cystic fibrosis care center on outcomes after lung transplantation for cystic fibrosis

BACKGROUND

The purpose of this study was to evaluate outcomes in people with cystic fibrosis (CF) who underwent lung transplant (LT) at a transplant center with an accredited Cystic Fibrosis Care Center (CFCC) in the United States.

METHODS

We reviewed the Scientific Registry of Transplant Recipients for all adult patients with CF who received a first-time LT from 2005 to 2018. The primary outcome was graft failure. Unadjusted Kaplan-Meier analysis and adjusted multilevel Cox proportional hazards models were used to evaluate outcomes in CF patients undergoing lung transplantation at a CFCC.

RESULTS

2,573 patients with CF underwent a first time LT during the study period. Of the 68 lung transplantation centers, 50 were CFCCs (73.5%). After adjustment for potential confounders, patients who underwent lung transplantation at a hospital with an accredited CFCC had a 33% reduction in risk of death or re-transplantation compared to those transplanted at a hospital without an accredited CFCC (HR: 0.67, 95% CI: 0.56-0.82, p < 0.001).

CONCLUSIONS

People with CF who undergo LT at a transplant center with a CFCC have improved graft survival and decreased need for re-transplantation compared to those who undergo LT at a non-CFCC, independent of volume.

Generation of functional ciliated cholangiocytes from human pluripotent stem cells

The derivation of mature functional cholangiocytes from human pluripotent stem cells (hPSCs) provides a model for studying the pathogenesis of cholangiopathies and for developing therapies to treat them. Current differentiation protocols are not efficient and give rise to cholangiocytes that are not fully mature, limiting their therapeutic applications. Here, we generate functional hPSC-derived cholangiocytes that display many characteristics of mature bile duct cells including high levels of cystic fibrosis transmembrane conductance regulator (CFTR) and the presence of primary cilia capable of sensing flow. With this level of maturation, these cholangiocytes are amenable for testing the efficacy of cystic fibrosis drugs and for studying the role of cilia in cholangiocyte development and function. Transplantation studies show that the mature cholangiocytes generate ductal structures in the liver of immunocompromised mice indicating that it may be possible to develop cell-based therapies to restore bile duct function in patients with biliary disease.

Non-invasive tools for detection of liver disease in children and adolescents with cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is a multi-organ genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene which encodes the CFTR protein. CF-associated liver disease (CFLD) is a common complication; diagnosis is based on clinical, laboratory findings and abdominal imaging. However, non-invasive diagnostic approaches are needed to early detect CFLD, its progression and severity. Recent studies demonstrate a possible role of point shear wave elastography (p-SWE) with liver stiffness measurement (LSM) as a tool for CFLD diagnosis also in children. This non-invasive technique measures liver stiffness to assess liver fibrosis and is suggested to be less operator-dependent compared to ultrasonography. Aim of our prospective observational study is to investigate the role of p-SWE with LSM for CFLD diagnosis in children and adolescents with CF and to compare this finding with aspartate aminotransferase to platelet ratio index (APRI), fibrosis index based on four factors (FIB-4) and gamma-glutamyl-transpeptidase to platelet ratio (GPR) indices.

METHODS

Fifty-nine children with CF, who had routinely undergone abdominal imaging, were consecutively enrolled. Laboratory findings and clinical data were recorded, as abdominal ultrasound and shear wave elastography at baseline. The cases were divided into two groups based on collected data and classified as CFLD and CFnoLD (without liver disease) according to Debray criteria. APRI, FIB-4 and GPR fibrosis indices were also evaluated.

RESULTS

Twenty-four/59 (40.7%) were defined as CFLD. LSM test is superior to the APRI (P<0.001), the FIB-4 test (P=0.001) and the GPR test for early detection of liver fibrosis. LSM had an area under receiver operating characteristic (ROC) curve =0.818 (95% CI: 0.702-0.934) compared with APRI (0.571, 95% CI: 0.421-0.722), FIB-4 (0.656, 95% CI: 0.511-0.801) and GPR (0.632, 95% CI: 0.485-0.779). At a cut-off of ≥6.2 LSM show a sensitivity of 75.0% and a specificity of 88.6%.

CONCLUSIONS

LSM by transient p-SWE is a non-invasive, highly accessible, reliable, and reproducible test that can be used to assess early detection of liver fibrosis and its severity in children and adolescents with CF, limiting the use of liver biopsy. These preliminary observations point to the need of larger study population to confirm our data.

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.

Hyperinflammation and airway surface liquid dehydration in cystic fibrosis: purinergic system as therapeutic target

OBJECTIVE AND DESIGN

The exacerbate inflammatory response contributes to the progressive loss of lung function in cystic fibrosis (CF), a genetic disease that affects the osmotic balance of mucus and mucociliary clearance, resulting in a microenvironment that favors infection and inflammation. The purinergic system, an extracellular signaling pathway characterized by nucleotides, enzymes and receptors, may have a protective role in the disease, through its action in airway surface liquid (ASL) and anti-inflammatory response.

MATERIALS AND METHODS

To make up this review, studies covering topics of CF, inflammation, ASL and purinergic system were selected from the main medical databases, such as Pubmed and ScienceDirect.

CONCLUSION

We propose several ways to modulate the purinergic system as a potential therapy for CF, like inhibition of P2X7, activation of P2Y2, A2A and A2B receptors and blocking of adenosine deaminase. Among them, we postulate that the most suitable strategy is to block the action of adenosine deaminase, which culminates in the increase of Ado levels that presents anti-inflammatory actions and improves mucociliary clearance. Furthermore, it is possible to maintain the physiological levels of ATP to control the hydration of ASL. These therapies could correct the main mechanisms that contribute to the progression of CF.

[Clinical characteristics and gene variants of patients with infantile intrahepatic cholestasis]

OBJECTIVE

To explore the clinical characteristics and genetic findings of patients with infantile intrahepatic cholestasis.

METHODS

The clinical data were collected in children who were admitted to the Department of Gastroenterology in Children's Hospital, Capital Institute of Pediatrics from June 2017 to June 2019 and were suspected of inherited metabolic diseases. Next generation sequencing based on target gene panel was used for gene analysis in these children. Sanger sequencing technology was used to verify the genes of the members in this family.

RESULTS

Forty patients were enrolled. Pathogenic gene variants were identified in 13 patients (32%), including SLC25A13 gene variation in 3 patients who were diagnosed with citrin deficiency, JAG1 gene variation in 3 patients who were diagnosed with Alagille syndrome, ABCB11 gene variation in 3 patients who were diagnosed with progressive familial intrahepatic cholestasis type 2, HSD3B7 gene variation in 1 patient who was diagnosed with congenital bile acid synthesis defect type 1, AKR1D1 gene variation in 1 patient who was diagnosed with congenital bile acid synthesis defect type 1, NPC1 gene variation in 1 patient who was diagnosed with Niemann-Pick disease, and CFTR gene variation in 1 patient who was diagnosed with cystic fibrosis.

CONCLUSIONS

The etiology of infantile intrahepatic cholestasis is complex. Next generation sequencing is helpful in the diagnosis of infantile intrahepatic cholestasis.

A new era for people with cystic fibrosis

Cystic fibrosis is the most prevalent inherited disease caused by a defect in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The impaired electrolyte homeostasis caused by the mutated or absent protein leads to symptoms in multiple organ systems. However, the pulmonary manifestation with chronic infections and eventually respiratory failure remains the most important threat. Until one decade ago, only symptomatic treatment was available. However, since 2012, different combinations of CFTR modulators are available for people with cystic fibrosis (pwCF) that carry different mutations. The advent of these drugs has impressively changed life expectancy and quality of life in people with cystic fibrosis and raised new challenges regarding long-term complications and tapering of conventional therapies.Conclusion: In this review, we provide an update on the latest developments around diagnostics, treatment, and prognosis of pwCF. What is Known: • Cystic fibrosis is an incurable and life-shortening disease asking for life-long symptomatic treatment. • Three combination CFTR modulating drugs has gained marked approval over the last 10 years. What is New: • The emerge of new (modulating) therapies contribute to the increasing life expectancy. • A high unmet need to develop new therapies for people with CF who cannot access or benefit from these drugs remains. This review gives an update on the current status.

Novel therapeutic approaches for the management of cystic fibrosis

Cystic fibrosis (CF) is a genetic condition characterised by the build-up of thick, sticky mucus that can damage many of the body's organs. It is a life-long disease that results in a shortened life expectancy, often due to the progression of advanced lung disease. Treatment has previously targeted the downstream symptoms such as diminished mucus clearance and recurrent infection. More recently, significant advances have been made in treating the cause of the disease by targeting the faulty gene responsible. Hope for the development of potential therapies lies with ongoing research into new pharmacological agents and gene therapy. This review gives an overview of CF, and summarises the current evidence regarding the disease management and upcoming strategies aimed at treating or potentially curing this condition.

Assessment of Selected Parameters of Liver Fibrosis and Inflammation in Patients with Diagnosed Cystic Fibrosis

Changes in the liver and bile ducts observed in patients diagnosed with cystic fibrosis result from inflammatory processes as well as fibrosis, remodeling, apoptosis, and cholestasis. As a consequence, portal hypertension, cirrhosis, and hepatic failure may develop. So far, the complexity of these processes has not been elucidated. Study Objectives. The aim of the study was to evaluate the selected parameters of hepatitis and fibrosis (Fibrotest, Actitest, and APRI) in patients diagnosed with cystic fibrosis. Material and Methods. The study included 79 patients with cystic fibrosis, aged 1 to 20 years (mean age 9.8 years), 49 girls (62%) and 30 boys (38%). The analysis involved the following: age, sex, clinical manifestations, laboratory tests evaluating pancreas function, parameters of liver damage, and cholestasis. Fibrotest, Actitest, and APRI were performed in all subjects. Results. Elevated parameters of hepatic cell damage (hypertransaminasemia) were found in 31/79 (39.2%) patients, while abnormal cholestasis parameters in 21/79 (26.6%). The abnormal results of Fibrotest were reported in 15% of patients (12/79), while of Actitest in 10% (8/79). In contrast, elevated APRI values were found in only 7.6% (6/79) of subjects. There was a statistically significant correlation between APRI and age (higher values were observed in younger children) and between Fibrotest and Actitest and pancreatic insufficiency (higher values were found in subjects without this abnormality). Moreover, Fibrotest values were significantly higher in girls. There was no correlation between Fibrotest, Actitest, and APRI values and the type of mutation. Conclusion. It appears that Fibrotest may be used as an early marker of liver fibrosis in patients with cystic fibrosis. Increased APRI values were only found in subjects with advanced hepatic lesions, most often in the form of portal hypertension.

Gut-Liver Axis and Inflammasome Activation in Cholangiocyte Pathophysiology

The Nlrp3 inflammasome is a multiprotein complex activated by a number of bacterial products or danger signals and is involved in the regulation of inflammatory processes through caspase-1 activation. The Nlrp3 is expressed in immune cells but also in hepatocytes and cholangiocytes, where it appears to be involved in regulation of biliary damage, epithelial barrier integrity and development of fibrosis. Activation of the pathways of innate immunity is crucial in the pathophysiology of hepatobiliary diseases, given the strong link between the gut and the liver. The liver secretes bile acids, which influence the bacterial composition of the gut microbiota and, in turn, are heavily modified by microbial metabolism. Alterations of this balance, as for the development of dysbiosis, may deeply influence the composition of the bacterial products that reach the liver and are able to activate a number of intracellular pathways. This alteration may be particularly important in the pathogenesis of cholangiopathies and, in particular, of primary sclerosing cholangitis, given its strong association with inflammatory bowel disease. In the present review, we summarize current knowledge on the gut–liver axis in cholangiopathies and discuss the role of Nlrp3 inflammasome activation in cholestatic conditions.

Regulation of CFTR Biogenesis by the Proteostatic Network and Pharmacological Modulators

Cystic fibrosis (CF) is the most common lethal inherited disease among Caucasians in North America and a significant portion of Europe. The disease arises from one of many mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator, or CFTR. The most common disease-associated allele, F508del, along with several other mutations affect the folding, transport, and stability of CFTR as it transits from the endoplasmic reticulum (ER) to the plasma membrane, where it functions primarily as a chloride channel. Early data demonstrated that F508del CFTR is selected for ER associated degradation (ERAD), a pathway in which misfolded proteins are recognized by ER-associated molecular chaperones, ubiquitinated, and delivered to the proteasome for degradation. Later studies showed that F508del CFTR that is rescued from ERAD and folds can alternatively be selected for enhanced endocytosis and lysosomal degradation. A number of other disease-causing mutations in CFTR also undergo these events. Fortunately, pharmacological modulators of CFTR biogenesis can repair CFTR, permitting its folding, escape from ERAD, and function at the cell surface. In this article, we review the many cellular checkpoints that monitor CFTR biogenesis, discuss the emergence of effective treatments for CF, and highlight future areas of research on the proteostatic control of CFTR.

Effects of aerobic interval training on glucose tolerance in children and adolescents with cystic fibrosis: a randomized trial protocol

Background

Individuals with cystic fibrosis (CF) may develop CF-related diabetes (CFDR). This comorbidity is related to a poorer quality of life, microvascular complications, a decline in lung function, and an increase in exacerbations, as well as delayed growth and puberty. Evidence exists that physical exercise contributes to glycemic control in individuals with non-CF-related diabetes. This exercise is usually continuous with moderate intensity and long duration, which can cause muscle dyspnea and fatigue in CF individuals. Aerobic interval training (AIT) emerges as a safe and effective alternative for treating these individuals. The objective of this study is to evaluate the effects of AIT on glucose tolerance in children and adolescents with CF.

Methods

This study will be a two-arm, prospectively registered, randomized controlled trial with blind assessors and twenty 6- to 18-year-old individuals with cystic fibrosis (CF) from two different Brazilian states. People with CF will be randomly allocated to either the experimental or control group using block randomization, stratified by puberty stage,. Participants from both groups will receive an educational intervention and will be asked to continue their usual daily treatment for the full duration of the study. Those in the experimental group will perform AIT on a cycle ergometer at home three times a week, for 8 consecutive weeks. The sample characterization will include an assessment of puberty stage, socioeconomic status, dyspnea, and anthropometry. The primary outcome will be the change in glucose tolerance, while the secondary outcomes will include lung function, exercise tolerance, respiratory muscle strength, quality of life, and CF exacerbations. All outcomes will be assessed at baseline, week 9, and week 17.

Discussion

This is the first study to evaluate the effects of AIT on glucose tolerance in children and adolescents with CF. This study will serve as a basis for guiding clinical practice and decision-making in treating glucose intolerance and CF-related diabetes (CFRD) in children and adolescents with CF.

Trial registration

ClinicalTrials.gov Protocol Registration System: NCT03653949. Registered on August 31, 2018.

Cystic Fibrosis Liver Disease: Know More

Cystic fibrosis (CF) is a multisystem disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. CFTR is expressed in the apical surface of cholangiocytes. Homozygous CFTR gene mutation results in viscous and acidic bile secretions secondary to deficient surface fluid and bicarbonate efflux. Viscous, inspissated bile causes ductular obstruction and hepatotoxicity from retained bile components, leading to fibrosis and ultimately cirrhosis, known as CF liver disease (CFLD). CFLD is the third leading cause of death in CF patients. CFLD manifestations can take many forms. They range from asymptomatic elevation of transaminases to cirrhosis and end-stage liver disease. CFLD is diagnosed after excluding other causes of chronic liver disease. To date, there is no effective therapy to prevent or treat CFLD. Management of CFLD emphasizes on optimizing nutritional status. Ursodeoxycholic acid is the only available treatment that may prevent progression of CFLD at present. All CF patients with CFLD need annual investigations and follow-up for early detection of the disease. Liver transplantation should be considered in patients with decompensated cirrhosis and portal hypertension, with acceptable long-term outcomes. Novel therapies of CFLD are promising. This review article aims to summarize the published literature on CFLD, its pathophysiology, clinical features and complications, and management including new therapeutic options.

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.

Molecular Mechanisms in Pediatric Cholestasis

Pediatric cholestasis often results from mechanical obstruction of the biliary tract or dysfunction in the processes of forming and excreting bile. Various genetic defects with resulting molecular inaccuracies are increasingly being recognized, often with specific clinical characteristics. Identifying of the molecular abnormality can enable implementation of timely, appropriate treatment in some affected individuals and provide prognostic indicators for both families and care teams.

Recent advances in understanding liver fibrosis: bridging basic science and individualized treatment concepts

Hepatic fibrosis is characterized by the formation and deposition of excess fibrous connective tissue, leading to progressive architectural tissue remodeling. Irrespective of the underlying noxious trigger, tissue damage induces an inflammatory response involving the local vascular system and the immune system and a systemic mobilization of endocrine and neurological mediators, ultimately leading to the activation of matrix-producing cell populations. Genetic disorders, chronic viral infection, alcohol abuse, autoimmune attacks, metabolic disorders, cholestasis, alterations in bile acid composition or concentration, venous obstruction, and parasite infections are well-established factors that predispose one to hepatic fibrosis. In addition, excess fat and other lipotoxic mediators provoking endoplasmic reticulum stress, alteration of mitochondrial function, oxidative stress, and modifications in the microbiota are associated with non-alcoholic fatty liver disease and, subsequently, the initiation and progression of hepatic fibrosis. Multidisciplinary panels of experts have developed practice guidelines, including recommendations of preferred therapeutic approaches to a specific cause of hepatic disease, stage of fibrosis, or occurring co-morbidities associated with ongoing loss of hepatic function. Here, we summarize the factors leading to liver fibrosis and the current concepts in anti-fibrotic therapies.