Current Status of Liver Transplantation for Primary Biliary Cholangitis

Treatment of Primary Biliary Cholangitis including Transplantation

Ursodeoxycholic acid (UDCA) is the first-line treatment of primary biliary cholangitis (PBC). Long-term UDCA use significantly reduces progression to cirrhosis. UDCA improves liver enzymes and transplant-free survival rates. Despite the association between PBC and hyperlipidemia, treatment is indicated under specific circumstances with statins and fibrates being safe options. Osteoporosis, which is frequently seen, is usually managed based on data from postmenopausal women. Sicca syndrome is treated similarly to its standalone condition with the use of hydroxypropyl methylcellulose eye drops and anticholinergic drugs.

Sex differences in chronic liver disease and benign liver lesions

The epidemiology, natural history, and therapeutic responses of chronic liver diseases and liver lesions often vary by sex. In this review, we summarize available clinical and translational data on these aspects of the most common liver conditions encountered in clinical practice, including the potential contributions of sex hormones to the underlying pathophysiology of observed differences. We also highlight areas of notable knowledge gaps and discuss sex disparities in access to liver transplant and potential strategies to address these barriers. Given established sex differences in immune response, drug metabolism, and response to liver-related therapies, emerging clinical trials and epidemiological studies should prioritize dedicated analyses by sex to inform sex-specific approaches to liver-related care.

Primary biliary cholangitis: Epidemiology, prognosis, and treatment

Primary biliary cholangitis (PBC) is a chronic cholestatic autoimmune liver disease characterized by a destructive, small duct, and lymphocytic cholangitis, and marked by the presence of antimitochondrial antibodies. The incidence and prevalence of PBC vary widely in different regions and time periods, and although disproportionally more common among White non-Hispanic females, contemporary data show a higher prevalence in males and racial minorities than previously described. Outcomes largely depend on early recognition of the disease and prompt institution of treatment, which, in turn, are directly influenced by provider bias and socioeconomic factors. Ursodeoxycholic acid remains the initial treatment of choice for PBC, with obeticholic acid and fibrates (off-label therapy) reserved as add-on therapy for the management of inadequate responders or those with ursodeoxycholic acid intolerance. Novel and repurposed drugs are currently at different stages of clinical development not only for the treatment of PBC but also for its symptomatic management. Here, we summarize the most up-to-date data regarding the epidemiology, prognosis, and treatment of PBC, providing clinically useful information for its holistic management.

Post-Transplant Immunosuppression in Autoimmune Liver Disease

Autoimmune liver diseases (AILDs) are a group of conditions where immune-mediated liver damage can lead to the need for transplantation. Collectively, they account for almost a quarter of all liver transplants. Outcomes in terms of graft and patient survival for all liver transplants have improved markedly over decades with improvements in patient selection, surgical techniques and longer-term care and this is also seen in patients with AILDs. The current five- and ten-year survival rates post-transplant in autoimmune disease are excellent, at 88% and 78%, respectively. A key factor in maintaining good outcomes post liver transplant for these autoimmune conditions is the immunosuppression strategy. These patients have increased the rates of rejection, and autoimmune conditions can all recur in the graft ranging from 12 to 60% depending on the population studied. Immunosuppressive regimens are centred on calcineurin inhibitors, often combined with low dose corticosteroids, with or without the addition of antimetabolite therapy. There is no clear evidence-based immunosuppressive regimen for these conditions, and a tailored approach balancing the individuals' immunological profile against the risks of immunosuppression is often used. There are disease-specific considerations to optimised graft function including the role of ursodeoxycholic acid in both primary biliary cholangitis and primary sclerosing cholangitis and the role and timing of colectomy in primary sclerosing cholangitis in inflammatory bowel disease patients. However, unmet needs still exist in the management of AILDs post liver transplantation particularly in building the evidence base for optimal immunosuppression as well as mitigating the risk of recurrent disease.

Pretransplant Evaluation and Liver Transplantation Outcome in PBC Patients

Primary biliary cholangitis (PBC) is an autoimmune chronic cholestatic liver disease characterized by progressive cholangiocyte and bile duct destruction leading to fibrosis and finally to liver cirrhosis. The presence of disease-specific serological antimitochondrial antibody (AMA) together with elevated alkaline phosphatase (ALP) as a biomarker of cholestasis is sufficient for diagnosis. Ursodeoxycholic acid (UDCA) is the first treatment option for PBC. Up to 40% of patients have an incomplete response to therapy, and over time disease progresses to liver cirrhosis. Several risk scores are proposed for better evaluation of patients before and during treatment to stratify patients at increased risk of disease progression. GLOBE score and UK PBC risk score are used for the evaluation of UDCA treatment and Mayo risk score for transplant-free survival. Liver transplantation (LT) is the only treatment option for end-stage liver disease. More than 10 years after LT, 40% of patients experience recurrence of the disease. A liver biopsy is required to establish rPBC (recurrent primary biliary cholangitis). The only treatment option for rPBC is UDCA, and data show biochemical and clinical improvement, plus potential beneficial effects for use after transplantation for the prevention of rPBC development. Additional studies are required to assess the full impact of rPBC on graft and recipient survival and for treatment options for rPBC.

Excess liver transplant waitlist mortality for patients with primary biliary cholangitis under MELD-Na allocation

BACKGROUND

Historically, patients with primary biliary cholangitis (PBC) experience waitlist mortality and low rates of liver transplant (LT). Herein, the impact of MELD-Na based allocation on PBC waitlist mortality was examined.

METHODS

Adult patients with PBC were compared to those with alcohol-related liver disease (ALD) or non-alcoholic steatohepatitis (NASH) listed for LT from 2013 to 2019 in OPTN. Competing risk regression evaluated waitlist mortality in the MELD and MELD-Na eras using propensity score weights.

RESULTS

Overall, 1508 patients with PBC, 13581 with ALD, and 10455 with NASH were examined. In the MELD-Na era, 24-month cumulative incidence of waitlist mortality for PBC was 23.0% (95%CI 19.7-26.5%), ALD 13.9% (95%CI 13.1-14.8%), and NASH 20.0% (95%CI 18.9-21.2%). Using propensity score weights, adjusted risk of waitlist mortality was higher for PBC versus ALD (HR = 1.45, 95%CI 1.22-1.71) and NASH (HR = 1.32, 95%CI 1.14-1.55). Furthermore, among PBC, waitlist mortality risk per five-point elevation in MELD-Na (HR = 1.22, 95%CI 1.11-1.35) and Karnofsky score ≤30% (HR = 2.02, 95%CI 1.39-2.92) was significantly higher than among ALD (HR = 1.08, 95%CI 1.04-1.13; HR = 1.28, 95%CI 1.10-1.49) and NASH (HR = 1.05, 95%CI 1.00-1.09; HR = 1.16, 95%CI .99-1.37; all P-interactions < .05).

CONCLUSIONS

The MELD-Na score continues to underestimate risk of waitlist death for patients with PBC relative to ALD and NASH and highlights need for additional score modifications or exceptions.

Identification of the Representative Primary Biliary Cholangitis Cohort in Taiwan: A Comparison of Four Nationwide Cohorts

BACKGROUND/PURPOSE

The rates and outcomes of primary biliary cholangitis (PBC) in Taiwan remain unclear.

METHODS

A nationwide population-based cohort study (Taiwan National Health Insurance Research Database, 2002-2015) was conducted. Data from four PBC cohorts with various definitions were compared (cohort 1 (C1): ICD-9-CM (571.6); C2: alkaline phosphatase (Alk-P) and antimitochondrial antibody (AMA) measurements; C3: Alk-p and AMA measurements and ursodeoxycholic acid (UDCA) treatment; C4: ICD-9-CM (571.6), Alk-p and AMA measurements and UDCA treatment).

RESULTS

The average prevalence rate ranged from 9.419/10⁵ (C4) to 307.658/10⁵ (C2), and the female-to-male ratio ranged from 1.192 (C1) to 3.66 (C4). Prevalence rates increased over time in all cohorts. The average incidence rates ranged from 1.456/10⁵ (C4) to 66.386/10⁵ (C2). Incidence rates decreased over time in C1 (-9.09%, p < 0.0001) and C4 (-6.68%, p < 0.0001) and remained steady in the others. C4 had the lowest prevalence and incidence rates and highest female-to-male ratio. Cirrhosis rates ranged from 7.21% (C2) to 39.34% (C4), hepatoma rates ranged from 2.77%(C2) to 6.66%(C1), liver transplantation (LT) rates ranged from 1.07% (C2) to 6.77% (C4), and mortality rates ranged from 18.24% (C2) to 47.36% (C1). C4 had the highest LT (6.77%), osteoporosis (13.87%) and dyslipidemia rates (17.21%).

CONCLUSIONS

Based on the reported ranges of reasonable rates, female predominance and characteristic outcomes, C4 was the most representative Taiwanese PBC cohort, with average prevalence and incidence rates of 9.419/10⁵ and 1.456/10⁵, respectively, and a female-to-male ratio of 3.66. In a 14-year period, cirrhosis, hepatoma, LT, and mortality were noted in 39.34%, 5.52%, 6.77%, and 34.22% of C4 patients, respectively.

Management of Autoimmune Liver Diseases after Liver Transplantation

Autoimmune liver diseases are characterized by immune-mediated inflammation and eventual destruction of the hepatocytes and the biliary epithelial cells. They can progress to irreversible liver damage requiring liver transplantation. The post-liver transplant goals of treatment include improving the recipient’s survival, preventing liver graft-failure, and decreasing the recurrence of the disease. The keystone in post-liver transplant management for autoimmune liver diseases relies on identifying which would be the most appropriate immunosuppressive maintenance therapy. The combination of a steroid and a calcineurin inhibitor is the current immunosuppressive regimen of choice for autoimmune hepatitis. A gradual withdrawal of glucocorticoids is also recommended. On the other hand, ursodeoxycholic acid should be initiated soon after liver transplant to prevent recurrence and improve graft and patient survival in primary biliary cholangitis recipients. Unlike the previously mentioned autoimmune diseases, there are not immunosuppressive or disease-modifying agents available for patients with primary sclerosing cholangitis. However, colectomy and annual colonoscopy are key components during the post-liver transplant period.

CXCL12-CXCR4-Mediated Chemotaxis Supports Accumulation of Mucosal-Associated Invariant T Cells Into the Liver of Patients With PBC

Objectives: To explore the potential role of CD3⁺CD8⁺CD161^high TCRVα7.2⁺ mucosal-associated invariant T (MAIT) cells in the pathogenesis of primary biliary cholangitis (PBC).

Methods: We enrolled 55 patients with PBC, 69 healthy controls (HCs), and 8 patients with hepatic hemangioma. Circulating MAIT cells and their chemokine receptor profiles and cytokine production were quantified using flow cytometry. Liver-resident MAIT cells were examined by immunofluorescence staining. CXCL12-mediated chemotaxis of MAIT cells was measured using a transwell migration assay. Plasma interleukin (IL)-18 was measured using ELISA, and cytokine production in IL-18-stimulated MAIT cells was detected using flow cytometry.

Result: Peripheral MAIT cells were found to be significantly lower in patients with PBC (3.0 ± 3.2% vs. 9.4 ± 8.0%, p < 0.01) and negatively correlated with alkaline phosphatase (ALP) levels (r = −0.3209, p < 0.05). Liver immunofluorescence staining suggested that MAIT cells might accumulate in PBC liver. MAIT cells from patients with PBC expressed higher levels of CXCR4 (84.8 ± 18.0% vs. 58.7 ± 11.4%, p < 0.01), and the expression of CXCL12 was higher in PBC liver. CXCL12 promoted MAIT cell chemotaxis (70.4 ± 6.8% vs. 52.2 ± 3.5%, p < 0.01), which was attenuated by CXCR4 antagonist. MAIT cells from PBC produced significantly more interferon-γ (IFN-γ) (88.3 ± 4.2% vs. 64.2 ± 10.1%, p < 0.01), tumor necrosis factor-α (TNF-α) (93.0 ± 1.1% vs. 80.1 ± 5.3%, p < 0.01), Granzyme B (89.3 ± 3.3% vs. 72.1 ± 7.0%, p < 0.01), and perforin (46.8 ± 6.6% vs. 34.8 ± 7.7%, p < 0.05). MAIT cells from PBC expressed higher levels of IL18-Rα (83.8 ± 10.2% vs. 58.3 ± 8.7%, p < 0.01). Plasma IL-18 was more abundant in patients with PBC (286.8 ± 75.7 pg/ml vs. 132.9 ± 78.1 pg/ml, p < 0.01). IL-18 promoted IFN-γ production in MAIT cells (74.9 ± 6.6% vs. 54.7 ± 6.7%, p < 0.01), which was partially attenuated by blocking IL-18R (68.6 ± 8.3% vs. 43.5 ± 4.2%, p < 0.01).

Conclusion: Mucosal-associated invariant T cells from patients with PBC accumulated in the liver via CXCL12-CXCR4-mediated chemotaxis, produced pro-inflammatory cytokines, and contributed to portal inflammation, which was potentially mediated by elevated IL-18. Targeting MAIT cells might be a therapeutic approach for PBC.

A Clinical Review of Primary Biliary Cholangitis

Primary biliary cholangitis is a slowly progressive immune-mediated cholestatic disease that causes a destruction of the intrahepatic bile ducts and may lead to cirrhosis of the liver, end-stage liver disease, and the need for liver transplantation. The disease is among the most common reasons why adults require liver transplantation. The primary signs of the disease include the presence of antimitochondrial and antinuclear antibodies, elevated alkaline phosphatase, hyperbilirubinemia, hypercholesterolemia, and histologic features, such as intense inflammation with a florid duct lesion and hepatic fibrosis. The patient's quality of life is impacted by fatigue, pruritus, malabsorption syndrome, sicca syndrome, osteoporosis, and challenges coping with chronic illness. Advanced practice registered nurses need to understand the pathophysiology, clinical presentation, diagnostic approaches, disease and symptom management, and priority nursing assessment and care in patients with this rare disease to differentiate it from primary sclerosing cholangitis, autoimmune hepatitis, obstructed bile duct lesions, drug-induced cholestasis, cholestasis in pregnancy, cholangiocarcinoma, hepatic malignancy, and peptic ulcer disease.

Primary biliary cholangitis

Primary biliary cholangitis is an autoimmune liver disease that predominantly affects women. It is characterised by a chronic and destructive, small bile duct, granulomatous lymphocytic cholangitis, with typical seroreactivity for antimitochondrial antibodies. Patients have variable risks of progressive ductopenia, cholestasis, and biliary fibrosis. Considerations for the cause of this disease emphasise an interaction of chronic immune damage with biliary epithelial cell responses and encompass complex, poorly understood genetic risks and environmental triggers. Licensed disease-modifying treatment focuses on amelioration of cholestasis, with weight-dosed oral ursodeoxycholic acid. For patients who do not respond sufficiently, or patients with ursodeoxycholic acid intolerance, conditionally licensed add-on therapy is with the FXR (NR1H4) agonist, obeticholic acid. Off-label therapy is recognised as an alternative, notably with the pan-PPAR agonist bezafibrate; clinical trial agents are also under development. Baseline characteristics, such as young age, male sex, and advanced disease, and serum markers of liver injury, particularly bilirubin and ALP, are used to stratify risk and assess treatment responsiveness. Parallel attention to the burden of patient symptoms is paramount, including pruritus and fatigue.

Synthesis and characterization of new impurities in obeticholic acid

Novel and efficient synthetic strategies are developed for the first synthesis of two new impurities found in obeticholic acid. The synthetic routes to the impurities are designed without column purification using 4-nitrobenzoyl chloride as a selective protecting group. The impurities, which are obtained in good yields and high purity, are identified and characterized using high-resolution mass spectrometry, Fourier transform infrared, one-dimensional nuclear magnetic resonance (1H, 13C, distortionless enhancement by polarization transfer), and two-dimensional nuclear magnetic resonance (Correlated Spectroscopy, heteronuclear single quantum coherence, heteronuclear multiple bond correlation, and rotating-frame Overhauser effect spectroscopy) techniques.