Continuous 13C-methacetin breath test differentiates biliary atresia from other causes of neonatal cholestasis

mRNA and lncRNA expression profiles of liver tissues in children with biliary atresia

Progressive liver fibrosis is the most common phenotype in biliary atresia (BA). A number of pathways contribute to the fibrosis process so comprehensive understanding the mechanisms of liver fibrosis in BA will pave the way to improve patient's outcome after operation. In this study, the differentially expressed profiles of mRNAs and long non-coding RNAs from BA and choledochal cyst (CC) liver tissues were investigated and analyzed, which may provide potential clues to clarify hepatofibrosis mechanism in BA. A total of two BA and two CC liver tissue specimens were collected, the expression level of mRNAs and lncRNAs was detected by RNA sequencing. Differentially expressed mRNAs (DEmRNAs) were functionally annotated and protein-protein interaction networks (PPI) was established to predict the biological roles and interactive relationships. Differentially expressed lncRNAs (DElncRNAs) nearby targeted DEmRNA network and DElncRNA-DEmRNA co-expression network were constructed to further explore the roles of DElncRNAs in BA pathogenesis. The expression profiles of significant DEmRNAs were validated in Gene Expression Omnibus database. A total of 2,086 DEmRNAs and 184 DElncRNAs between BA and CC liver tissues were obtained. DEmRNAs were enriched in 521 Gene Ontology terms and 71 Kyoto Encyclopedia of Genes and Genomes terms which were mainly biological processes and metabolic pathways related to immune response and inflammatory response. A total of five hub proteins (TYRO protein tyrosine kinase binding protein, C-X-C motif chemokine ligand 8, pleckstrin, Toll-like receptor 8 and C-C motif chemokine receptor 5) were found in the PPI networks. A total of 31 DElncRNA-nearby-targeted DEmRNA pairs and 2,337 DElncRNA-DEmRNA co-expression pairs were obtained. The expression of DEmRNAs obtained from RNA sequencing were verified in GSE46960 dataset, generally. The present study identified key genes and lncRNAs participated in BA associated liver fibrosis, which may present a new avenue for understanding the patho-mechanism for hepatic fibrosis in BA.

European guideline on indications, performance and clinical impact of 13 C-breath tests in adult and pediatric patients: An EAGEN, ESNM, and ESPGHAN consensus, supported by EPC

INTRODUCTION

13 C-breath tests are valuable, noninvasive diagnostic tests that can be widely applied for the assessment of gastroenterological symptoms and diseases. Currently, the potential of these tests is compromised by a lack of standardization regarding performance and interpretation among expert centers.

METHODS

This consensus-based clinical practice guideline defines the clinical indications, performance, and interpretation of 13 C-breath tests in adult and pediatric patients. A balance between scientific evidence and clinical experience was achieved by a Delphi consensus that involved 43 experts from 18 European countries. Consensus on individual statements and recommendations was established if ≥ 80% of reviewers agreed and <10% disagreed.

RESULTS

The guideline gives an overview over general methodology of 13 C-breath testing and provides recommendations for the use of 13 C-breath tests to diagnose Helicobacter pylori infection, measure gastric emptying time, and monitor pancreatic exocrine and liver function in adult and pediatric patients. Other potential applications of 13 C-breath testing are summarized briefly. The recommendations specifically detail when and how individual 13 C-breath tests should be performed including examples for well-established test protocols, patient preparation, and reporting of test results.

CONCLUSION

This clinical practice guideline should improve pan-European harmonization of diagnostic approaches to symptoms and disorders, which are very common in specialist and primary care gastroenterology practice, both in adult and pediatric patients. In addition, this guideline identifies areas of future clinical research involving the use of 13 C-breath tests.

Ontogeny of Phase I Metabolism of Drugs

Capturing ontogeny of enzymes involved in phase I metabolism is crucial to improve prediction of dose-concentration and concentration-effect relationships throughout infancy and childhood. Once captured, these patterns can be integrated in semiphysiologically or physiology-based pharmacokinetic models to support predictions in specific pediatric settings or to support pediatric drug development. Although these translational efforts are crucial, isoenzyme-specific ontogeny-based models should also incorporate data on variability of maturational and nonmaturational covariates (eg, disease, treatment modalities, pharmacogenetics). Therefore, this review provides a summary of the ontogeny of phase I drug-metabolizing enzymes, indicating current knowledge gaps and recent progresses. Furthermore, we tried to illustrate that straightforward translation of isoenzyme-specific ontogeny to predictions does not allow full exploration of scenarios of potential variability related to maturational (non-age-related variability, other isoenzymes or transporters) or nonmaturational (disease, pharmacogenetics) covariates, and necessitates integration in a "systems" concept.

Breath test using 13C methacetin does not seem to be useful in the assessment of liver function in girls with anorexia nervosa: a case control study

BACKGROUND

Anorexia nervosa (AN) concerns approximately up to 1.8% of the pediatric female population. One of the complications that can occur in the course of this disease is acute liver failure. This study's objective was to assess the usefulness of the 13C labeled Methacetin Breath Test (MBT) in the diagnostics of the liver function in girls with eating disorders.

METHODS

For the study 81 girls aged 12 to 17 years were recruited, including 41 patients with confirmed diagnosis of AN (mean age 14.7 ± 1.48 years) and 40 age-matched controls. The diagnosis was based on the present Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria. Weight and height were measured in all study participants and the Body Mass Index (BMI) was calculated. In the study and control group laboratory tests assessing the liver function and the MBT were performed.

RESULTS

In all controls the anthropometric as well as laboratory liver function parameters were normal. In the study group 25 patients (61%) had BMI below the lower limit for age. The total percentage of 13CO2 recovery in the 120th minute of the test did not exceed the lower limit in patients and controls. A result of the 13CO2 cumulative recovery above the upper normal range was found in 18 girls with AN (44% of the study group) and 2 controls (5%). Patients with AN were characterized by significantly higher 13CO2 cumulative dose recovery after ingestion of the substrate in comparison to the control group in all time points of the test.

CONCLUSIONS

The obtained results confirm a significant stimulation of the liver metabolism of 13C labeled methacetin in female patients with AN. The increased cumulative dose recovery of the substrate in girls with AN impacts the credibility of this measurement and implies a risk of false negative results.

13C Methacetin Breath Test for Assessment of Microsomal Liver Function: Methodology and Clinical Application

Assessment of the liver function, and the need of constant monitoring of the organ's capacity, concerns not only patients with primary liver diseases, but also those at risk of hepatopathies secondary to other chronic diseases. Most commonly, the diagnostics is based on measurements of static biochemical parameters, which allow us to draw conclusions only indirectly about the function and the degree of damage of the organ. On the other hand, liver biopsy is an invasive procedure and therefore it is associated with a considerable risk of complications. Dynamic tests enable us to assess quantitatively the organ's functional reserve by analyzing the kinetics of the metabolization of the substrate by the liver. In practice applied are breath tests using substances such as aminopyrine, caffeine, methacetin, erythromycin (for assessment of the microsomal function); phenylalanine, galactose (for assessment of the cytosolic function); methionine, octanoate, ketoisocaproic acid (for assessment of the mitochondrial function). The test with ¹³C methacetin belongs to the best described and most widely applied methods in noninvasive liver function assessment. Due to the rising availability of this method, knowledge concerning its limitations and controversies regarding the methodology, as well as its usefulness in chosen groups of patients, seems to be vital.

Evaluation of Exalenz Bioscience's BreathID for Helicobacter pylori detection

Carbon-labeled urea breath tests, which have high sensitivity and specificity, are the preferred method used in epidemiological studies, screening dyspeptic patients and assessing eradication or recurrence of Helicobacter pylori infection. The principle of the (13)C-urea breath test relies upon the ability of the H. pylori urease to hydrolyze the orally administered (13)C-urea. The BreathID (Exalenz Bioscience Inc., Union, NJ, USA) provides a competitive solution for breath testing, including unique features such as automatic continuous breath collection and analysis. This is an unattended convenient test, with no human error as the correct part of the breath is collected and patients' assistance is not required. The test results are available in real time at the point of care and enable shortened breath testing procedures. Additionally, several studies showing expanded utility of the BreathID in pediatrics, after therapy and during proton pump inhibitors intake, further support the safety and performance of the BreathID in the diagnosis of H. pylori.

Activity of cytochrome P450 1A2 in relation to hepatic iron accumulation in transfusion-dependent β-thalassaemia major patients

BACKGROUND

Cytochrome P450 1A2 (CYP1A2) is a cytochrome enzyme with a pivotal role in hepatic drug metabolism. Data from CYP1A2((-/-)) mouse suggest that CYP1A2 plays a role in aspects of hepatic iron toxicity. The aim of this study was to assess the activity of CYP1A2 in relation to hepatic iron load in patients with transfusion-dependent β-thalassaemia major.

METHODS

The (13) C-methacetin continuous breath test was performed on 30 consecutive patients with transfusion-dependent β-thalassaemia major. CYP1A2 activity was measured by the rate at which the (13) C substrate is metabolized and exhaled expressed as percentage dose recovery (PDR) per hour. CYP1A2 activity was correlated with clinical and laboratory parameters and hepatic iron accumulation by T2* magnetic resonance imaging (T2*MRI).

RESULTS

Cytochrome P450 1A2 activity in patients with transfusion-dependent β- thalassaemia major was positivity correlated with plasma ferritin levels. No correlation was found with age, duration and amount of red blood cell transfusion and type of iron chelation therapy. Low CYP1A2 activity was negatively associated with hepatic iron accumulation (T2*MRI ≤ 6.3 ms); adjusted odds ratio (OR; 95% CI) for hepatic iron accumulation in patients with low CYP1A2 activity was 0.047 (0.003-0.72; P = 0.021). Of the six patients with decreased activity of CYP1A2, five had no hepatic iron accumulation and one had mild hepatic iron accumulation by T2*MRI.

CONCLUSION

Activity of CYP1A2 is associated with hepatic iron accumulation in patients with transfusion-depended β-thalassaemia major. Further studies are needed to assess the exact role of CYP1A2 in iron metabolism in human.

Cholestasis in the newborn and infant

Neonatal cholestasis occurs in approximately 1 in 2500 term infants, the most common underlying disease being biliary atresia, viral infections and α1-antitrypsin deficiency. The incidence of cholestasis is much higher in extremely premature newborns. The etiology of biliary atresia remains unclear, which in turn makes the search for additional treatments to surgery challenging. Reliable non-invasive tools to differentiate biliary atresia from other forms of neonatal cholestasis need to be further investigated. Despite important findings in the last decades, the pathogenesis of cholestatic liver disease in α1-antitrypsin deficiency remains to be clarified. Any such explanation would also need to explain why only a minority of individuals with PiZZ phenotype develop liver disease. For other genetic diseases causing neonatal cholestasis, such as Alagille's syndrome and progressive familial intrahepatic cholestasis the breakthrough within the field of molecular biology has definitely deepened our understanding of both etiology and pathogenesis. However, the correlation between genotype and phenotype is rarely obvious and for several patients with the seemingly correct phenotype no known genetic mutation is detected. A stepwise approach to the management of cholestasis in the newborn and infant is suggested, where percutaneous liver biopsy is of value to select patients with suspected biliary atresia for laparotomy.