The study of biliary disease has been constrained by a lack of primary human cholangiocytes. Here we present an efficient, serum-free protocol for directed differentiation of human induced ...pluripotent stem cells into cholangiocyte-like cells (CLCs). CLCs show functional characteristics of cholangiocytes, including bile acids transfer, alkaline phosphatase activity, γ-glutamyl-transpeptidase activity and physiological responses to secretin, somatostatin and vascular endothelial growth factor. We use CLCs to model in vitro key features of Alagille syndrome, polycystic liver disease and cystic fibrosis (CF)-associated cholangiopathy. Furthermore, we use CLCs generated from healthy individuals and patients with polycystic liver disease to reproduce the effects of the drugs verapamil and octreotide, and we show that the experimental CF drug VX809 rescues the disease phenotype of CF cholangiopathy in vitro. Our differentiation protocol will facilitate the study of biological mechanisms controlling biliary development, as well as disease modeling and drug screening.
Summary
Background
Despite considerable advances over the last two decades in the molecular understanding of cholestasis and cholestatic liver disease, little improvement has been made in diagnostic ...tools and therapeutic strategies.
Aims
To critically review controversial aspects of the scientific basis for common clinical practice in primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) and to discuss key ongoing challenges to improve patient management.
Methods
We performed a literature search using PubMed and by examining the reference lists of relevant review articles related to the clinical management of PBC and PSC. Articles were considered on the background of the European Association for the Study of the Liver (EASL) and the American Association for the Study of Liver Diseases (AASLD) practice guidelines and clinical experience of the authors.
Results
Ongoing challenges in PBC mainly pertain to the improvement of medical therapy, particularly for patients with a suboptimal response to ursodeoxycholic acid. In PSC, development of medical therapies and sensitive screening protocols for cholangiocarcinoma represent areas of intense research. To rationally improve patient management, a better understanding of pathogenesis, including complications like pruritis and fatigue, is needed and there is a need to identify biomarker end‐points for treatment effect and prognosis. Timing of liver transplantation and determining optimal regimens of immunosuppression post‐liver transplantation will also benefit from better appreciation of pre‐transplant disease mechanisms.
Conclusion
Controversies in the management of PBC and PSC relate to topics where evidence for current practice is weak and further research is needed.
Cancer remains one of the most serious long‐term complications after liver transplantation (LT). Data for all adult LT patients between 1982 and 2013 were extracted from the Nordic Liver Transplant ...Registry. Through linkage with respective national cancer‐registry data, we calculated standardized incidence ratios (SIRs) based on country, sex, calendar time, and age‐specific incidence rates. Altogether 461 cancers were observed in 424 individuals of the 4246 LT patients during a mean 6.6‐year follow‐up. The overall SIR was 2.22 (95% confidence interval CI, 2.02‐2.43). SIRs were especially increased for colorectal cancer in recipients with primary sclerosing cholangitis (4.04) and for lung cancer in recipients with alcoholic liver disease (4.96). A decrease in the SIR for cancers occurring within 10 years post‐LT was observed from the 1980s: 4.53 (95%CI, 2.47‐7.60), the 1990s: 3.17 (95%CI, 2.70‐3.71), to the 2000s: 1.76 (95%CI, 1.51‐2.05). This was observed across age‐ and indication‐groups. The sequential decrease for the SIR of non‐Hodgkin lymphoma was 25.0‐12.9‐7.53, and for nonmelanoma skin cancer 80.0‐29.7‐10.4. Cancer risk after LT was found to be decreasing over time, especially for those cancers that are strongly associated with immunosuppression. Whether immunosuppression minimization contributed to this decrease merits further study.
This multicenter study from four countries finds that overall cancer incidence after liver transplantation has decreased over time relative to the general population, especially for immunosuppression‐related cancer types.
We sought to identify factors that are predictive of liver transplantation or death in patients with primary sclerosing cholangitis (PSC), and to develop and validate a contemporaneous risk score for ...use in a real‐world clinical setting. Analyzing data from 1,001 patients recruited to the UK‐PSC research cohort, we evaluated clinical variables for their association with 2‐year and 10‐year outcome through Cox‐proportional hazards and C‐statistic analyses. We generated risk scores for short‐term and long‐term outcome prediction, validating their use in two independent cohorts totaling 451 patients. Thirty‐six percent of the derivation cohort were transplanted or died over a cumulative follow‐up of 7,904 years. Serum alkaline phosphatase of at least 2.4 × upper limit of normal at 1 year after diagnosis was predictive of 10‐year outcome (hazard ratio HR = 3.05; C = 0.63; median transplant‐free survival 63 versus 108 months; P < 0.0001), as was the presence of extrahepatic biliary disease (HR = 1.45; P = 0.01). We developed two risk scoring systems based on age, values of bilirubin, alkaline phosphatase, albumin, platelets, presence of extrahepatic biliary disease, and variceal hemorrhage, which predicted 2‐year and 10‐year outcomes with good discrimination (C statistic = 0.81 and 0.80, respectively). Both UK‐PSC risk scores were well‐validated in our external cohort and outperformed the Mayo Clinic and aspartate aminotransferase‐to‐platelet ratio index (APRI) scores (C statistic = 0.75 and 0.63, respectively). Although heterozygosity for the previously validated human leukocyte antigen (HLA)‐DR*03:01 risk allele predicted increased risk of adverse outcome (HR = 1.33; P = 0.001), its addition did not improve the predictive accuracy of the UK‐PSC risk scores. Conclusion: Our analyses, based on a detailed clinical evaluation of a large representative cohort of participants with PSC, furthers our understanding of clinical risk markers and reports the development and validation of a real‐world scoring system to identify those patients most likely to die or require liver transplantation.
Objectives
Recent metabolomic, experimental and clinical studies have demonstrated that trimethylamine‐N‐oxide (TMAO), a microbiota‐dependent metabolite from dietary phosphatidylcholine and ...carnitine, is a strong predictor of coronary artery disease (CAD). This finding suggests a link between the gut microbiota and atherosclerosis. The potential impact of TMAO in chronic heart failure (HF) is unknown. We hypothesized that TMAO levels would provide prognostic information about adverse outcomes in chronic HF.
Design
Prospective, observational study including 155 consecutive patients with chronic HF. In addition, 100 patients with stable CAD without HF and 33 matched healthy individuals were included as controls. Plasma levels of TMAO and its precursors choline and betaine were measured, and associations with symptoms, aetiology and transplant‐free survival in the patients with HF were explored.
Results
Plasma levels of TMAO (P = 0.01), choline (P < 0.001) and betaine (P < 0.001) were elevated in patients with chronic HF compared to control subjects, with the highest levels in patients with New York Heart Association (NYHA) classes III and IV. Furthermore, TMAO levels were highest in individuals with ischaemic HF, followed by those with stable CAD and nonischaemic HF. TMAO, but not choline or betaine, was associated with reduced transplant‐free survival: approximately 50% of patients in the upper tertile of TMAO levels died or received a heart transplant during 5.2 years of follow‐up (unadjusted Cox‐regression: hazard ratio 2.24, 95% confidence interval 1.28–3.92, P = 0.005).
Conclusions
TMAO levels were elevated in patients with HF and associated with NYHA class, ischaemic aetiology and adverse outcomes. Future studies should focus on gut microbiota, dietary composition and intestinal dysfunction in relation to TMAO levels and clinical outcome in HF.
Human gut microbiota is an important determinant for health and disease, and recent studies emphasize the numerous factors shaping its diversity. Here we performed a genome-wide association study ...(GWAS) of the gut microbiota using two cohorts from northern Germany totaling 1,812 individuals. Comprehensively controlling for diet and non-genetic parameters, we identify genome-wide significant associations for overall microbial variation and individual taxa at multiple genetic loci, including the VDR gene (encoding vitamin D receptor). We observe significant shifts in the microbiota of Vdr
mice relative to control mice and correlations between the microbiota and serum measurements of selected bile and fatty acids in humans, including known ligands and downstream metabolites of VDR. Genome-wide significant (P < 5 × 10
) associations at multiple additional loci identify other important points of host-microbe intersection, notably several disease susceptibility genes and sterol metabolism pathway components. Non-genetic and genetic factors each account for approximately 10% of the variation in gut microbiota, whereby individual effects are relatively small.
Common variable immunodeficiency (CVID) patients have reduced gut microbial diversity compared to healthy controls. The reduced diversity is associated with gut leakage, increased systemic ...inflammation and ten "key" bacteria that capture the gut dysbiosis (dysbiosis index) in CVID. Rifaximin is a broad-spectrum non-absorbable antibiotic known to reduce gut leakage (lipopolysaccharides, LPS) in liver disease. In this study, we explored as a 'proof of concept' that altering gut microbial composition could reduce systemic inflammation, using CVID as a disease model. Forty adult CVID patients were randomized, (1:1) to twice-daily oral rifaximin 550 mg versus no treatment for 2 weeks in an open-label, single-centre study. Primary endpoints were reduction in plasma/serum levels of soluble (s) CD14, sCD25, sCD163, neopterin, CRP, TNF, LPS and selected cytokines measured at 0, 2 and 8 weeks. Secondary endpoint was changes in intra-individual bacterial diversity in stool samples. Rifaximin-use did not significantly change any of the inflammation or gut leakage markers, but decreased gut microbial diversity compared with no treatment (p = 0.002). Importantly, the gut bacteria in the CVID dysbiosis index were not changed by rifaximin. The results suggest that modulating gut microbiota by rifaximin is not the chosen intervention to affect systemic inflammation, at least not in CVID.
Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency characterized by low immunoglobulin (Ig)G and IgA, and/or IgM. In addition to bacterial infections, a ...large subgroup has noninfectious inflammatory and autoimmune complications. We performed 16S ribosomal RNA-based profiling of stool samples in 44 CVID patients, 45 patients with inflammatory bowel disease (disease controls), and 263 healthy controls. We measured plasma lipopolysaccharide (LPS) and markers of immune cell activation (i.e., soluble (s) CD14 and sCD25) in an expanded cohort of 104 patients with CVID and in 30 healthy controls. We found a large shift in the microbiota of CVID patients characterized by a reduced within-individual bacterial diversity (alpha diversity, P<0.001) without obvious associations to antibiotics use. Plasma levels of both LPS (P=0.001) and sCD25 (P<0.0001) were elevated in CVID, correlating negatively with alpha diversity and positively with a dysbiosis index calculated from the taxonomic profile. Low alpha diversity and high dysbiosis index, LPS, and immune markers were most pronounced in the subgroup with inflammatory and autoimmune complications. Low level of IgA was associated with decreased alpha diversity, but not independently from sCD25 and LPS. Our findings suggest a link between immunodeficiency, systemic immune activation, LPS, and altered gut microbiota.
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