Genetic association analysis identifies variants associated with disease progression in primary sclerosing cholangitis.

OBJECTIVE: Primary sclerosing cholangitis (PSC) is a genetically complex, inflammatory bile duct disease of largely unknown aetiology often leading to liver transplantation or death. Little is known about the genetic contribution to the severity and progression of PSC. The aim of this study is to identify genetic variants associated with PSC disease progression and development of complications. DESIGN: We collected standardised PSC subphenotypes in a large cohort of 3402 patients with PSC. After quality control, we combined 130 422 single nucleotide polymorphisms of all patients-obtained using the Illumina immunochip-with their disease subphenotypes. Using logistic regression and Cox proportional hazards models, we identified genetic variants associated with binary and time-to-event PSC subphenotypes. RESULTS: We identified genetic variant rs853974 to be associated with liver transplant-free survival (p=6.07×10-9). Kaplan-Meier survival analysis showed a 50.9% (95% CI 41.5% to 59.5%) transplant-free survival for homozygous AA allele carriers of rs853974 compared with 72.8% (95% CI 69.6% to 75.7%) for GG carriers at 10 years after PSC diagnosis. For the candidate gene in the region, RSPO3, we demonstrated expression in key liver-resident effector cells, such as human and murine cholangiocytes and human hepatic stellate cells. CONCLUSION: We present a large international PSC cohort, and report genetic loci associated with PSC disease progression. For liver transplant-free survival, we identified a genome-wide significant signal and demonstrated expression of the candidate gene RSPO3 in key liver-resident effector cells. This warrants further assessments of the role of this potential key PSC modifier gene.

Enhanced liver fibrosis test predicts transplant-free survival in primary sclerosing cholangitis, a multi-centre study.

BACKGROUND & AIMS: Biomarkers reflecting disease activity and prognosis in primary sclerosing cholangitis (PSC) have not been firmly established. Enhanced liver fibrosis (ELF) test was previously reported to predict outcome in PSC. We aimed to validate the prognostic utility of ELF test in an independent, multi-centre, retrospective PSC study population. METHODS: We collected serum samples from PSC patients from seven countries. We estimated rates of transplant-free survival by the Kaplan-Meier method, used Cox proportional hazards regression to explore the association between ELF test and clinical outcome and determined prognostic performance of ELF test by computing the area under the receiver operating characteristic (AUC-ROC) curve. RESULTS: The final analysis included 534 PSC patients (61% males). Features of autoimmune hepatitis or concomitant inflammatory bowel disease affected 44 (8%) and 379 (71%) patients respectively. ELF test levels were higher in patients reaching the combined endpoint liver transplantation or death (median 10.9 [Interquartile range (IQR): 9.8-12.1]; n=24 deaths, 79 liver transplantations) compared to those censored (8.8 [IQR: 8.0-9.8]); P<.001. ELF test expressed as mild, moderate and severe fibrosis was significantly associated with the risk of reaching the endpoint (P<.001). ELF test independently predicted clinical outcome (Hazard ratio 1.31; 95% confidence interval [1.05-1.65]; P=.018), and enabled good discrimination between PSC patients with and without endpoint (AUC-ROC: 0.79). CONCLUSION: Our retrospective data validates the predictive utility of ELF test for clinical outcomes in PSC. The clinical utility of biomarkers for fibrosis in patients with PSC should be assessed in prospective patient cohorts.

Validation of the prognostic value of histologic scoring systems in primary sclerosing cholangitis: An international cohort study.

Histologic scoring systems specific for primary sclerosing cholangitis (PSC) are not validated. We recently determined the applicability and prognostic value of three histological scoring systems in a single PSC cohort. The aim of this study was to validate their prognostic use and reproducibility across a multicenter PSC cohort. Liver biopsies from PSC patients were collected from seven European institutions. Histologic scoring was performed using the Nakanuma, Ishak, and Ludwig scoring systems. Biopsies were independently scored by six liver pathologists for interobserver agreement. The prognostic value of clinical, biochemical, and all three histologic scoring systems on predicting composite endpoints 1 (PSC-related death and liver transplantation), 2 (liver transplantation), and 3 (liver-related events), was assessed using univariable and multivariable Cox proportional hazards modeling. A total of 119 PSC patients were identified, and the median follow-up was 142 months. During follow-up, 31 patients died (20 PSC-related deaths), 31 patients underwent liver transplantation, and 35 patients experienced one or more liver-related events. All three staging systems were independent predictors of endpoints 2 and 3 (Nakanuma system: hazard ratio [HR], 3.16 [95% confidence interval (CI), 1.49-6.68] for endpoint 2 and HR, 2.05 [95% CI, 1.17-3.57] for endpoint 3; Ishak system: HR, 1.55 [95% CI, 1.10-2.18] for endpoint 2 and HR, 1.43 [95% CI, 1.10-1.85] for endpoint 3; Ludwig system: HR, 2.62 [95% CI, 1.19-5.80] for endpoint 2 and HR, 2.06 [95% CI, 1.09-3.89] for endpoint 3). Only the Nakanuma staging system was independently associated with endpoint 1: HR, 2.14 (95% CI, 1.22-3.77). Interobserver agreement was moderate for Nakanuma stage (κ = 0.56) and substantial for Nakanuma component fibrosis (κ = 0.67), Ishak stage (κ = 0.64), and Ludwig stage (κ = 0.62). CONCLUSION: We confirm the independent prognostic value and demonstrate for the first time the reproducibility of staging disease progression in PSC using the Nakanuma, Ishak, and Ludwig staging systems. The Nakanuma staging system-incorporating features of chronic biliary disease-again showed the strongest predictive value. (Hepatology 2017;65:907-919).

Alkaline phosphatase at diagnosis of primary sclerosing cholangitis and 1 year later: evaluation of prognostic value.

BACKGROUND: Primary sclerosing cholangitis (PSC) is a slowly progressive liver disease. Reliable biomarkers to predict outcome are urgently needed to serve as surrogate endpoints and/or stratifiers in clinical trials. Reduction in serum alkaline phosphatase (ALP) has been proposed as prognostic surrogate marker in PSC. The aim of this study was to asses if ALP at diagnosis (T0), 1 year later (T1), and percentage change between both time points hold prognostic value, and to determine the optimal threshold. METHODS: We retrospectively collected ALP levels at T0 and T1 for patients included in a large PSC cohort. The association of ALP at T0, T1, and percentage change with the combined endpoint (PSC-related death, liver transplantation) was analysed. Predictive value was determined using C-statistics. RESULTS: A total of 366 patients were included, of whom 66 (18%) reached an endpoint: 26 (7%) PSC-related death, 40 (11%) liver transplantation. At T0 and T1, 84% used ursodeoxycholic acid. A positive association was observed between level of ALP at T0 and T1 and the hazard of reaching an endpoint, up to values around 2.5 times upper limit of normal (xULN). A larger decrease in ALP between T0 and T1 decreased the event rate. A range of thresholds (0.5-3×ULN) with about similar C-statistics was found. In this cohort, the optimal threshold was 1.3×ULN at T1. CONCLUSION: ALP can be used to discriminate between PSC patients with a good and a poor prognosis. These findings indicate that ALP can serve as stratifier, and potentially as surrogate endpoint for clinical trials in PSC.

Risk factors for primary sclerosing cholangitis.

BACKGROUND & AIMS: Primary sclerosing cholangitis (PSC) is a progressive cholestatic liver disease of unknown cause, but strongly associated with inflammatory bowel disease (IBD). Potential risk factors triggering PSC have never been studied on a population level. The aim of this study was to evaluate smoking, appendectomy, family history and geographical distribution in a population-based cohort of PSC patients, as compared to IBD control patients and healthy controls (HC). METHODS: For this case-control study 343 PSC patients, 370 IBD controls and 232 HC's living in a geographically defined area in the Netherlands filled-out a questionnaire concerning smoking, appendectomy and family history of IBD and autoimmune liver diseases. RESULTS: Smoking was associated with a lower risk of developing PSC in PSC-ulcerative colitis (UC) patients (adjusted OR 0.21; 95% CI 0.12-0.34; P < 0.001). Comparable results were found for PSC-Crohn's disease (CD) patients (16% former smokers) compared to CD patients (55% former smokers) (adjusted OR 0.17; 95% CI 0.08-0.39; P < 0.001). Frequency of appendectomy did not differ between PSC and HC, but PSC-UC patients had undergone appendectomy more often than UC patients (13% vs. 6%) (adjusted OR 2.51; 95%CI 1.04-6.07; P = 0.041). We found no association between family history of IBD or autoimmune liver disease and risk of PSC. Degree of urbanization was not associated with PSC incidence. CONCLUSION: In this large population-based case-control study we confirm that smoking is associated with a lower risk of developing PSC, independent of its protective effect for developing UC. Appendectomy is not associated with the risk of developing PSC.

Applicability and prognostic value of histologic scoring systems in primary sclerosing cholangitis.

BACKGROUND & AIMS: Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease. At present, there is no appropriate histologic scoring system available for PSC, evaluating both degree of necroinflammatory activity (grade) and fibrosis (stage). The aim of this study was to assess if three scoring systems, commonly used in different liver diseases could be applied for grading and/or staging of PSC. METHODS: Sixty-four PSC patients from a Dutch cohort, who underwent diagnostic liver biopsy, were included. Staging was scored using Ishak, Nakanuma, and Ludwig systems. Grading was scored using Ishak and Nakanuma systems. Three measures of outcome were defined; transplant-free survival, time to liver transplantation (LTx) and occurrence of cirrhosis related symptoms (CRS). Association of grade and stage with outcome was estimated using Kaplan-Meier log-rank test, and Cox regression analysis. Correlation with biochemistry was assessed by Spearman's rank test. RESULTS: There were strong associations between disease stage measured by Ishak, Nakanuma, and Ludwig staging systems with both outcome measuring transplant-free survival (Hazard ratio (HR) 2.56; 95% CI 1.11-5.89, HR 6.53; 95% CI 2.01-21.22, HR 1.94; 95% CI 1.00-3.79, respectively), and time to LTx (HR 4.18; 95%CI 1.51-11.56, HR 7.05; 95% CI 1.77-28.11, HR 3.13; 95%CI 1.42-6.87, respectively). Ishak and Nakanuma grading systems were not associated with CRS. Weak correlations between histopathology and liver biochemistry were shown. CONCLUSION: Applying the Nakanuma, Ishak, and Ludwig histopathological staging systems is feasible and clinically relevant given their association with transplant-free survival and time to LTx. This suggests that these staging systems could be likely candidates for surrogate endpoints and stratification purposes in clinical trials in PSC.

Biomarkers for disease progression of primary sclerosing cholangitis.

PURPOSE OF REVIEW: Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown origin. There is no medical treatment of proven benefit on survival; once patients have progressed to end-stage liver disease, the only treatment option is liver transplantation. RECENT FINDINGS: Over the last years, some progress has been made in identifying biomarkers of PSC disease progression. Categories that can be distinguished include clinical and biochemical biomarkers, histology, imaging, prognostic modelling and genetics. With this review, we summarize biomarkers for progression of PSC from these six categories, which have been studied to date. SUMMARY: Biomarkers for the progression of PSC disease course can be used for several purposes. First of all, they can be implemented as surrogate endpoints for clinical trials. Second, biomarkers of disease progression form the basis of prognostic modelling, which is needed for proper patient counselling and management. Lastly, these biomarkers may yield a better understanding of PSC pathogenesis.