Canals of Hering loss relates to the progression of the histological stages of primary biliary cirrhosis

A placebo-controlled Phase 2 trial of E6011, anti-human fractalkine monoclonal antibody, in primary biliary cholangitis

BACKGROUND

While ursodeoxycholic acid (UDCA) remains the first-line therapy for primary biliary cholangitis (PBC), the autoimmune nature of PBC underscores the need for treatments targeting immunological pathways that may achieve a cure. E6011, a novel humanized anti-fractalkine monoclonal antibody, has emerged as a potential therapeutic option for PBC. We conducted a randomized, placebo-controlled, double-blind study to evaluate the efficacy and safety of E6011 in patients with PBC with an incomplete response to UDCA.

METHODS

The study was composed of 12-week Double-Blind Phase (placebo, E6011 10 mg/kg/month, 15 mg/kg/month, or 10 mg/kg/every other week [eow]) followed by a 52-week Open-Label Phase. The primary endpoint was the percent change in alkaline phosphatase (ALP) at Week 12.

RESULTS

A total of 29 patients were enrolled. Histological evaluation at screening revealed that 83 % of the enrolled patients were classified as Stage 4 according to the Nakanuma Classification. The mean percent changes in ALP at Week 12 were +0.45 % in the placebo, +0.65 % in the 10 mg/kg/month, +1.23 % in the 15 mg/kg/month and +1.19 % in the 10 mg/kg/eow, with no observed trends toward ALP reduction in the E6011 treatment. Based on the interim analysis, the study was discontinued due to a lack of the efficacy. E6011 was generally safe and well tolerated.

CONCLUSION

This study of E6011 failed to meet the primary endpoint in patients with PBC with an incomplete response to UDCA. The advanced histological severity present in more than 80 % of patients at baseline may have contributed to these findings.

The phenotypic landscape of primary biliary cholangitis and autoimmune hepatitis variants

Autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) stand as distinct diseases, yet occasionally intertwine with overlapping features, posing diagnostic and management challenges. This recognition traces back to the 1970s, with initial case reports highlighting this complexity. Diagnostic scoring systems like IAIHG and simplified criteria for AIH were introduced but are inherently limited in diagnosing variant syndromes. The so-called Paris criteria offer a diagnostic framework with high sensitivity and specificity for variant syndromes, although disagreements among international guidelines persist. Histological findings in AIH and PBC may exhibit overlapping features, rendering histology alone inadequate for a definitive diagnosis. Autoantibody profiles could be helpful, but similarly cannot be considered alone to reach a solid and consistent evaluation. Treatment strategies vary based on the predominant features observed. Individuals with overlapping characteristics favoring AIH ideally benefit from corticosteroids, while patients primarily manifesting PBC features should initially receive treatment with choleretic drugs like ursodeoxycholic acid (UDCA).

Secretin alleviates biliary and liver injury during late-stage primary biliary cholangitis via restoration of secretory processes

BACKGROUND & AIMS

Primary biliary cholangitis (PBC) is characterised by ductopenia, ductular reaction, impairment of anion exchanger 2 (AE2) and the 'bicarbonate umbrella'. Ductulo-canalicular junction (DCJ) derangement is hypothesised to promote PBC progression. The secretin (Sct)/secretin receptor (SR) axis regulates cystic fibrosis transmembrane receptor (CFTR) and AE2, thus promoting choleresis. We evaluated the role of Sct/SR signalling on biliary secretory processes and subsequent injury in a late-stage PBC mouse model and human samples.

METHODS

At 32 weeks of age, female and male wild-type and dominant-negative transforming growth factor beta receptor II (late-stage PBC model) mice were treated with Sct for 1 or 8 weeks. Bulk RNA-sequencing was performed in isolated cholangiocytes from mouse models.

RESULTS

Biliary Sct/SR/CFTR/AE2 expression and bile bicarbonate levels were reduced in late-stage PBC mouse models and human samples. Sct treatment decreased bile duct loss, ductular reaction, inflammation, and fibrosis in late-stage PBC models. Sct reduced hepatic bile acid levels, modified bile acid composition, and restored the DCJ and 'bicarbonate umbrella'. RNA-sequencing identified that Sct promoted mature epithelial marker expression, specifically anterior grade protein 2 (Agr2). Late-stage PBC models and human samples exhibited reduced biliary mucin 1 levels, which were enhanced by Sct treatment.

CONCLUSION

Loss of Sct/SR signalling in late-stage PBC results in a faulty 'bicarbonate umbrella' and reduced Agr2-mediated mucin production. Sct restores cholangiocyte secretory processes and DCJ formation through enhanced mature cholangiocyte phenotypes and bile duct growth. Sct treatment may be beneficial for individuals with late-stage PBC.

IMPACT AND IMPLICATIONS

Secretin (Sct) regulates biliary proliferation and bicarbonate secretion in cholangiocytes via its receptor, SR, and in mouse models and human samples of late-stage primary biliary cholangitis (PBC), the Sct/SR axis is blunted along with loss of the protective 'bicarbonate umbrella'. We found that both short- and long-term Sct treatment ameliorated ductular reaction, immune cell influx, and liver fibrosis in late-stage PBC mouse models. Importantly, Sct treatment promoted bicarbonate and mucin secretion and hepatic bile acid efflux, thus reducing cholestatic and toxic bile acid-associated injury in late-stage PBC mouse models. Our work perpetuates the hypothesis that PBC pathogenesis hinges on secretory defects, and restoration of secretory processes that promote the 'bicarbonate umbrella' may be important for amelioration of PBC-associated damage.

Liver stiffness measurements by 2-dimensional shear wave elastography compared to histological and ultrasound parameters in primary biliary cholangitis

BACKGROUND AND AIMS

Liver stiffness measurements (LSMs) by 2-dimensional-shear-wave elastography (LSM2D-SWE) are now widely used in hepatology. However, relevant information for primary biliary cholangitis (PBC) is scant. We compare LSM2D-SWE with liver biopsy (LB) in a cohort of PBC patients in Greece.

METHODS

Data of 68 LBs from 53 PBC patients were retrospectively analyzed and fibrosis stage was compared to LSM2D-SWE. Forty-six patients (86.8%) were females and at the time of LBx median (IQR) age was 62.6 (53.2-72.1). Demographic, UDCA treatment, histological and B-mode ultrasound data were tested for their influence on LSM2D-SWE estimates.

RESULTS

Liver fibrosis stages F0-F4 were found in 4, 19, 19, 16 and 10 cases, respectively. Across stages F0-F4, the LSM2D-SWE was 5.6 (5.1-6.1), 7.0 (5.8-7.7), 9.1 (7.3-11.5), 10.8 (9.9-12.2) and 14.5 (11.9-25.7) kPa, respectively, with highly significant difference (p<.001). The LSM2D-SWE differed also significantly between F0 vs. F1 (p=.027), F1 vs. F2 (p=.005) and F3 vs. F4 (p=.017). The discriminatory ability of LSM2D-SWE for mild, significant, severe fibrosis and cirrhosis was highly significant in all comparisons (p<.001), with AUC2D-SWE 95.3%, 87.4%, 85.3% and 95.3% and accuracy 89.7%, 85.3%, 80.9% and 86.8%, respectively. Among 21 parameters tested, significant predictors of LSM2D-SWE by multiple linear regression were fibrosis stage, portal inflammation and parenchymal heterogeneity. The portal inflammation grade accounted for 32.2% of LSM variation with adjusted R2 0.428.

CONCLUSIONS

In patients with PBC, LSM measurements by 2D-SWE can reliably discriminate between mild, significant, severe fibrosis and cirrhosis. Measurements are significantly affected by portal inflammation grade.

Autoimmune biliary diseases: primary biliary cholangitis and primary sclerosing cholangitis

Autoimmune cholestatic liver diseases are rare hepato-biliary disorders characterized by a progressive, inflammatory destruction of bile ducts. Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are the main autoimmune cholestatic liver diseases. Both may evolve into secondary biliary cirrhosis and its complications. Therapeutic options are limited and liver transplantation remains the only definitive treatment for PBC and PSC.

Most PBC and PSC patients have a typical presentation, which does not require liver biopsy. However, in routine clinical practice, important variants or specific subgroups that benefit from liver biopsy for proper management may be observed. Herein, we provide a general overview of clinical and pathological characteristic of PBC and PSC, highlighting the most important features for routine diagnostic practice.

Canal of Hering loss is an initiating step for primary biliary cholangitis (PBC): A hypothesis

The origin and initiating features of PBC remain obscure despite decades of study. However, recent papers have demonstrated loss of canals of Hering (CoH) to be the earliest histologic change in liver biopsy specimens from patients with primary biliary cholangitis (PBC). We posit that CoH loss prior to significant inflammation or evidence of bile duct injury might be a very early, perhaps even an initiating lesion of PBC. As a potential target of inflammatory or toxic injury, CoH loss may initiate rather than follow the cascade of events leading to duct injury and loss and their sequelae. Toxins may be exogenous in origin, such as environmental toxins or drug exposures, or endogenous, resulting from genetic or epigenetic alterations in canalicular bile transporters upstream from the CoH. In turn, this hypothesis suggests that loss of CoH would lead to altered bile flow and composition injurious to downstream bile ducts, because bile composition has not been modulated by normal CoH physiologic functions or because, in the absence of CoH, canalicular fluid flow into the biliary tree is disrupted interfering with soluble trophic factors important for bile duct integrity. Regardless of the pathogenic mechanism causing CoH loss, only following such loss would the characteristic diagnostic findings of PBC become evident: damage to downstream interlobular and sub-lobular bile ducts. To the extent that the causal mechanisms for CoH loss can be identified, clinical identification (as through early identification of CoH loss) and intervention (depending on the inciting cause) may offer promise for treatment of this enigmatic disease.

Liver fibrosis progression predicts survival in patients with primary biliary cirrhosis

Aim

The prognosis and natural history of primary biliary cirrhosis (PBC) has improved, and the clinical end‐point for PBC needs to be discovered. We aimed to identify surrogate markers for predicting long‐term prognosis in patients with PBC.

Methods

A total of 106 patients were divided into 53 responders and 53 non‐responders based on the median rate (69%) of decrease in γ‐glutamyl transpeptidase levels at 1 year after initiating ursodeoxycholic acid therapy. We aimed to identify the differences between ursodeoxycholic acid responders and non‐responders. Correlation of patient survival with histologic parameters based on Scheuer and Nakanuma staging systems was investigated. The Nakanuma system comprises grading for liver fibrosis and bile duct loss (BDL).

Results

The baseline pathological stage was the only factor that showed differences between the two groups. Patients in Scheuer stage 1 had a significantly better prognosis than patients in Scheuer stages 3 or 4 (P < 0.05 and P < 0.01, respectively), whereas patients in Nakanuma stage 1 had significantly better prognosis than patients in Nakanuma stage 4 (P < 0.01). Patients with Nakanuma fibrosis scores 2 and 3 had decreased survival compared with patients with fibrosis score 0 (P < 0.05 and P < 0.01, respectively), whereas patients with Nakanuma BDL score 3 had decreased survival compared with patients with BDL score 0 (P < 0.01).

Conclusion

Long‐term prognosis could be predicted by Scheuer stage 3 and Nakanuma fibrosis score 2, which were referred to as portal‐bridging fibrosis. Liver fibrosis has greater utility in predicting long‐term prognosis than BDL.