The relationship between disease activity and UDCA response criteria in primary biliary cholangitis: A cohort study

BACKGROUND

Uncertainty exists about how best to identify primary biliary cholangitis (PBC) patients who would benefit from second-line therapy. Existing, purely clinical, ursodeoxycholic acid (UDCA) response criteria accept degrees of liver biochemistry abnormality in responding patients, emerging data, however, suggest that any degree of ongoing abnormality may, in fact, be associated with an increased risk of adverse outcomes. This cohort study explores the link between response status, the biology of high-risk disease and its implications for clinical practice.

METHODS

Proteomics, exploring 19 markers previously identified as remaining elevated in PBC following UDCA therapy, were performed on 400 serum samples, from participants previously recruited to the UK-PBC Nested Cohort between 2014 and 2019. All participants had an established diagnosis of PBC and were taking therapeutic doses of UDCA for greater than 12 months. UDCA response status was assessed using Paris 1, Paris 2 and the POISE criteria, with additional analyses using normal liver blood tests stratified by bilirubin level. Statistical analysis using parametric t tests and 1-way ANOVA.

FINDINGS

Disease markers were statistically significantly higher in UDCA non-responders than in responders for all the UDCA response criteria, suggesting a meaningful link between biochemical disease status and disease mechanism. For each of the criteria, however, marker levels were also statistically significantly higher in responders with ongoing liver function test abnormality compared to those who had normalised their liver biochemistry. IL-4RA, IL-18-R1, CXCL11, 9 and 10, CD163 and ACE2 were consistently elevated across all responder groups with ongoing LFT abnormality. No statistically significant differences occurred between markers in normal LFT groups stratified by bilirubin level.

INTERPRETATION

This study provides evidence that any ongoing elevation in alkaline phosphatase levels in PBC after UDCA therapy is associated with some degree of ongoing disease activity. There was no difference in activity between patients with normal LFT when stratified by bilirubin. These findings suggest that if our goal is to completely control disease activity in PBC, then normalisation of alkaline phosphatase and bilirubin should be the treatment target. This would also simplify messaging around goals of therapy in PBC, benefiting both patients and clinicians.

FUNDING

Funding by the UK Medical Research Council (Stratified Medicine Programme) and an independent research grant by Pfizer. The study funders played no role in the study design, data collection, data analyses, data interpretation or manuscript writing.

The Serum Proteome and Ursodeoxycholic Acid Response in Primary Biliary Cholangitis

BACKGROUND AND AIMS

Stratified therapy has entered clinical practice in primary biliary cholangitis (PBC), with routine use of second-line therapy in nonresponders to first-line therapy with ursodeoxycholic acid (UDCA). The mechanism for nonresponse to UDCA remains, however, unclear and we lack mechanistic serum markers. The UK-PBC study was established to explore the biological basis of UDCA nonresponse in PBC and identify markers to enhance treatment.

APPROACH AND RESULTS

Discovery serum proteomics (Olink) with targeted multiplex validation were carried out in 526 subjects from the UK-PBC cohort and 97 healthy controls. In the discovery phase, untreated PBC patients (n = 68) exhibited an inflammatory proteome that is typically reduced in scale, but not resolved, with UDCA therapy (n = 416 treated patients). Nineteen proteins remained at a significant expression level (defined using stringent criteria) in UDCA-treated patients, six of them representing a tightly linked profile of chemokines (including CCL20, known to be released by biliary epithelial cells (BECs) undergoing senescence in PBC). All showed significant differential expression between UDCA responders and nonresponders in both the discovery and validation cohorts. A linear discriminant analysis, using serum levels of C-X-C motif chemokine ligand 11 and C-C motif chemokine ligand 20 as markers of responder status, indicated a high level of discrimination with an AUC of 0.91 (CI, 0.83-0.91).

CONCLUSIONS

UDCA under-response in PBC is characterized by elevation of serum chemokines potentially related to cellular senescence and was previously shown to be released by BECs in PBC, suggesting a potential role in the pathogenesis of high-risk disease. These also have potential for development as biomarkers for identification of high-risk disease, and their clinical utility as biomarkers should be evaluated further in prospective studies.

An international genome-wide meta-analysis of primary biliary cholangitis: Novel risk loci and candidate drugs

BACKGROUNDS & AIMS

Primary biliary cholangitis (PBC) is a chronic liver disease in which autoimmune destruction of the small intrahepatic bile ducts eventually leads to cirrhosis. Many patients have inadequate response to licensed medications, motivating the search for novel therapies. Previous genome-wide association studies (GWAS) and meta-analyses (GWMA) of PBC have identified numerous risk loci for this condition, providing insight into its aetiology. We undertook the largest GWMA of PBC to date, aiming to identify additional risk loci and prioritise candidate genes for in silico drug efficacy screening.

METHODS

We combined new and existing genotype data for 10,516 cases and 20,772 controls from 5 European and 2 East Asian cohorts.

RESULTS

We identified 56 genome-wide significant loci (20 novel) including 46 in European, 13 in Asian, and 41 in combined cohorts; and a 57th genome-wide significant locus (also novel) in conditional analysis of the European cohorts. Candidate genes at newly identified loci include FCRL3, INAVA, PRDM1, IRF7, CCR6, CD226, and IL12RB1, which each play key roles in immunity. Pathway analysis reiterated the likely importance of pattern recognition receptor and TNF signalling, JAK-STAT signalling, and differentiation of T helper (TH)1 and TH17 cells in the pathogenesis of this disease. Drug efficacy screening identified several medications predicted to be therapeutic in PBC, some of which are well-established in the treatment of other autoimmune disorders.

CONCLUSIONS

This study has identified additional risk loci for PBC, provided a hierarchy of agents that could be trialled in this condition, and emphasised the value of genetic and genomic approaches to drug discovery in complex disorders.

LAY SUMMARY

Primary biliary cholangitis (PBC) is a chronic liver disease that eventually leads to cirrhosis. In this study, we analysed genetic information from 10,516 people with PBC and 20,772 healthy individuals recruited in Canada, China, Italy, Japan, the UK, or the USA. We identified several genetic regions associated with PBC. Each of these regions contains several genes. For each region, we used diverse sources of evidence to help us choose the gene most likely to be involved in causing PBC. We used these 'candidate genes' to help us identify medications that are currently used for treatment of other conditions, which might also be useful for treatment of PBC.

Effects of Primary Biliary Cholangitis on Quality of Life and Health Care Costs in the United Kingdom

BACKGROUND & AIMS

There have been few high-quality studies of the costs, preference-based health-related quality of life (HRQoL) and cost effectiveness of treatments for primary biliary cholangitis (PBC). We aimed to estimate the marginal effects of PBC complications and symptoms, accounting for treatment, on HRQoL and the annual cost of health care in the United Kingdom (UK). These are essential components for evaluation of cost effectiveness and this information will aid in evaluation of new treatments.

METHODS

Questionnaires were mailed to 4583 participants in the UK-PBC research cohort and data were collected on HRQoL and use of the National Health Service (NHS) in the UK from 2015 through 2016. HRQoL was measured using the EQ-5D-5L instrument. The annual cost of resource use was calculated using unit costs obtained from NHS sources. We performed econometric analyses to determine the effects of treatment, symptoms, complications, liver transplantation status, and patient characteristics on HRQoL and annual costs.

RESULTS

In an analysis of data from 2240 participants (over 10% of all UK PBC patients), we found that PBC symptoms have a considerable effect on HRQoL. Ursodeoxycholic acid therapy was associated with significantly higher HRQoL regardless of response status. Having had a liver transplant and ascites were also independently associated with reduced HRQoL. Having had a liver transplant (US$4294) and esophageal varices (US$3401) were the factors with the two greatest mean annual costs to the NHS. Symptoms were not independently associated with cost but were associated with reduction in HRQoL for patients, indicating the lack of effective treatments for PBC symptoms.

CONCLUSIONS

In an analysis of data from 2240 participants in the UK PBC, we found that HRQoL and cost estimates provide greater insight into the relative importance of PBC-related symptoms and complications. These findings provide estimates for health technology assessments of new treatments for PBC.

PBC-10: a short quality of life measure for clinical screening in primary biliary cholangitis

BACKGROUND

Current guidelines in primary biliary cholangitis ( PBC) recommend routine screening for symptoms. However, at present there are no validated practical tools suitable for screening use in practice.

AIM

To develop a short quality of life questionnaire for PBC METHODS: The short PBC HRQL questionnaire was derived and validated by analysing the PBC-40 questionnaires from the UK-PBC Research Cohort. Construct validity was assessed using the European Quality of Life Five Dimensions (EQ5D) questionnaire. Test-retest analysis was done by asking a subgroup of patients to complete the questionnaire twice within 2-4 weeks.

RESULTS

A total of 2219 patients completed PBC-40 questionnaire in 2013. Stepwise regression identified 10 questions that contributed to more than 95% of the PBC-40 score variance and covered the main domains of PBC. The short HRQL questionnaire, PBC-10, had good internal consistency (Cronbach's α 0.905) and item-total correlations. PBC-10 demonstrated no ceiling effects but a floor effect was noted. Further validation on 2502 patients who completed the PBC questionnaire in 2017 confirmed the psychometric properties of PBC-10. Further analysis on 186 patients showed that PBC-10 demonstrated good internal consistency (Cronbach's α = 0.936), had good reproducibility (intra-class correlation coefficient = 0.945), good correlation with the EQ5D (r = .736), and was responsive to change. A change of 4 points in the PBC-10 score would be considered clinically important.

CONCLUSION

PBC-10 is a short and valid questionnaire for assessing the HRQL in patients with PBC in clinical practice.

A comparative study of initiation and development of embryogenic callus from haploid embryos of several barley cultivars. II. Cytophotometry of embryos and callus

Cells of haploid barley embryos (Hordeum vulgare L. 'Bruce', 'Perth', and 'Klages') and callus cells originating from embryos were cytophotometrically examined to determine the ploidy level. Specific embryo tissues regularly exhibited predictable ploidies and smaller embryos had a higher percentage of haploid cells than larger embryos of the same age. The predominantly haploid cells of the scutellar epidermis of the embryo initiated callus which generally, at least initially, was haploid. Monitoring of the ploidy evolution of these haploid calli showed that over a 6-month period each line exhibited its own unique rate of polyploidization, although lines of the same cultivar showed similar trends. Accumulation of cells at the diploid level was often a characteristic of these cultures.