Proposed therapies in primary biliary cholangitis

Clinical characteristics of primary biliary cirrhosis - idiopathic inflammatory myopathy overlap syndrome: A single center study

PURPOSE

Primary biliary cirrhosis-idiopathic inflammatory myopathy (PBC-IIM) overlap syndrome (OS) is a rare condition in which cardiac involvement is observed. We aimed to characterize the clinical features and associated factors of PBC-IIM OS patients with cardiac involvement.

METHODS

Patients with PBC-IIM OS that visited our hospital from January 1983 to December 2021 were enrolled. Clinical presentations and laboratory and imaging data were recorded. The clinical data of patients with and without cardiac involvement were compared. According to the first instance of a disease flare, prognostic factors were also studied.

RESULTS

Thirty-four patients with PBC-IIM OS were enrolled. A total of 58.8% of patients presented with muscle weakness at disease onset, which primarily involved skeletal muscle (85.3%). Slight liver dysfunction was discovered in this OS cohort. In patients with cardiac involvement, palpitation (63.6%) and dyspnea (36.4%) were the most common onset symptoms. Arrhythmia was a vital manifestation in OS patients, in which half of OS patients had nonsustained ventricular tachycardia (50.0%, 11/22). Compared with noncardiac involvement, myalgia (4.5%, P = 0.004) and fever (0.0%, P = 0.011) were reported relatively rarely at disease onset in the group with cardiac involvement. The prognosis analysis showed that positivity for anti-Ro52 (HR=0.00, P = 0.034) negatively correlated with relapse in OS patients.

CONCLUSION

PBC-IIM OS has unique features. Typical clinical manifestations and early worsening cardiac indicators can be used to identify cardiac involvement and predict prognosis. Anti-Ro52 may have prognostic value for PBC-IIM OS.

[Modern treatment of primary biliary cholangitis]

For nearly 30 years ursodeoxycholic acid (UDCA) represented the only pharmacological treatment option available for primary biliary cholangitis (PBC). This changed at the end of 2016 when obeticholic acid was licensed in Europe for PBC patients not responding to UDCA. Novel treatment concepts involving the modulation of nuclear receptor signaling in cholestatic and other liver diseases have led to a host of new potential options, studies and drug candidates for the treatment of PBC. The analysis of large multinational cohorts has additionally confirmed the effectiveness of UDCA in slowing PBC progression, and has led to the development of new definitions for the risk assessment of PBC patients under therapy, which will be an asset for clinical decision making. One issue that remains unresolved is the therapeutic management of extrahepatic symptoms associated with PBC, namely fatigue and pruritus, which are the main factors influencing the quality of life of affected individuals. Their pathophysiological basis is poorly understood and treatment remains unsatisfactory.

Cenicriviroc, a cytokine receptor antagonist, potentiates all-trans retinoic acid in reducing liver injury in cholestatic rodents

BACKGROUND & AIMS

Cholestatic liver injury is mediated by bile acid-induced inflammatory responses. We hypothesized that superior therapeutic effects might be achieved by combining treatments that reduce the bile acid pool size with one that blocks inflammation.

METHODS

Bile duct-ligated (BDL) rats and Mdr2(Abcb4)-/- mice were treated with all-trans retinoic acid (atRA), a potent inhibitor of bile acid synthesis, 5 mg/kg/d by gavage, or Cenicriviroc (CVC), a known antagonist of CCR2 and CCR5, 50 mg/kg/d alone or in combination for 14 days and 1 month respectively.

RESULTS

All-trans retinoic acid alone reduced bile acid pool size and liver necrosis in BDL rats. However, the combination with CVC further reduced liver to body weight ratio, bile acid pool size, plasma liver enzyme, bilirubin, liver necrosis and fibrosis when compared to the atRA treatment. The assessment of hepatic hydroxyproline content further confirmed the reduced liver injury concurrent with reduction of pro-inflammatory cytokines emphasizing the synergistic effects of these two agents. Profiling of hepatic inflammatory cells revealed that combination therapy reduced neutrophils and T cells but not macrophages. The superior therapeutic effects of combination treatment were also confirmed in Mdr2-/- mice where a significant reduction in plasma liver enzymes, bilirubin, liver fibrosis, bile duct proliferation and hepatic infiltration of neutrophils and T cells and expression of cytokines were found.

CONCLUSIONS

Multitargeted therapy is an important paradigm for treating cholestatic liver injury. The combination of CVC with atRA or other FXR activators may warrant a clinical trial in patients with cholestatic liver disease.

Junctional adhesion molecules JAM-B and JAM-C promote autoimmune-mediated liver fibrosis in mice

Fibrosis remains a serious health concern in patients with chronic liver disease. We recently reported that chemically induced chronic murine liver injury triggers increased expression of junctional adhesion molecules (JAMs) JAM-B and JAM-C by endothelial cells and de novo synthesis of JAM-C by hepatic stellate cells (HSCs). Here, we demonstrate that biopsies of patients suffering from primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) or autoimmune hepatitis (AIH) display elevated levels of JAM-C on portal fibroblasts (PFs), HSCs, endothelial cells and cholangiocytes, whereas smooth muscle cells expressed JAM-C constitutively. Therefore, localization and function of JAM-B and JAM-C were investigated in three mouse models of autoimmune-driven liver inflammation. A PBC-like disease was induced by immunization with 2-octynoic acid-BSA conjugate, which resulted in the upregulation of both JAMs in fibrotic portal triads. Analysis of a murine model of PSC revealed a role of JAM-C in PF cell-cell adhesion and contractility. In mice suffering from AIH, endothelial cells increased JAM-B level and HSCs and capsular fibroblasts became JAM-C-positive. Most importantly, AIH-mediated liver fibrosis was reduced in JAM-B^-/- mice or when JAM-C was blocked by soluble recombinant JAM-C. Interestingly, loss of JAM-B/JAM-C function had no effect on leukocyte infiltration, suggesting that the well-documented function of JAMs in leukocyte recruitment to inflamed tissue was not effective in the tested chronic models. This might be different in patients and may even be complicated by the fact that human leukocytes express JAM-C. Our findings delineate JAM-C as a mediator of myofibroblast-operated contraction of the liver capsule, intrahepatic vasoconstriction and bile duct stricture. Due to its potential to interact heterophilically with endothelial JAM-B, JAM-C supports also HSC/PF mural cell function. Together, these properties allow JAM-B and JAM-C to actively participate in vascular remodeling associated with liver/biliary fibrosis and suggest them as valuable targets for anti-fibrosis therapies.

Autoantibodies in Autoimmune Hepatitis: Can Epitopes Tell Us about the Etiology of the Disease?

Autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) are serious autoimmune liver diseases that are characterized by a progressive destruction of the liver parenchyma and/or the hepatic bile ducts and the development of chronic fibrosis. Left untreated autoimmune liver diseases are often life-threatening, and patients require a liver transplantation to survive. Thus, an early and reliable diagnosis is paramount for the initiation of a proper therapy with immunosuppressive and/or anticholelithic drugs. Besides the analysis of liver biopsies and serum markers indicating liver damage, the screening for specific autoantibodies is an indispensable tool for the diagnosis of autoimmune liver diseases. Such liver autoantigen-specific antibodies might be involved in the disease pathogenesis, and their epitope specificity may give some insight into the etiology of the disease. Here, we will mainly focus on the generation and specificity of autoantibodies in AIH patients. In addition, we will review data from animal models that aim toward a better understanding of the origins and pathogenicity of such autoantibodies.

Mesenchymal Stem Cells as New Therapeutic Agents for the Treatment of Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic autoimmune cholestatic liver disease characterized by the progressive destruction of small- and medium-sized intrahepatic bile ducts with resultant cholestasis and progressive fibrosis. Ursodeoxycholic acid and obethicholic acid are the only agents approved by the US Food and Drug Administration (FDA) for the treatment of PBC. However, for patients with advanced, end-stage PBC, liver transplantation is still the most effective treatment. Accordingly, the alternative approaches, such as mesenchymal stem cell (MSC) transplantation, have been suggested as an effective alternative therapy for these patients. Due to their immunomodulatory characteristics, MSCs are considered as promising therapeutic agents for the therapy of autoimmune liver diseases, including PBC. In this review, we have summarized the therapeutic potential of MSCs for the treatment of these diseases, emphasizing molecular and cellular mechanisms responsible for MSC-based effects in an animal model of PBC and therapeutic potential observed in recently conducted clinical trials. We have also presented several outstanding problems including safety issues regarding unwanted differentiation of transplanted MSCs which limit their therapeutic use. Efficient and safe MSC-based therapy for PBC remains a challenging issue that requires continuous cooperation between clinicians, researchers, and patients.

Chronic Autoimmune Epithelitis in Sjögren's Syndrome and Primary Biliary Cholangitis: A Comprehensive Review

Within the spectrum of autoimmune diseases, Sjögren's syndrome and primary biliary cholangitis are exemplary and can be coined as chronic epithelitis based on their frequent coexistence in clinical practice and the highly specific immune-mediated injury of the small bile ducts and the exocrine glands. The pathogenic mechanisms underlying the diseases are similar, with apoptosis being the key element leading to organ-specific immune-mediated injury directed against the small bile ducts and salivary gland epithelia, respectively along with similar epidemiological features, such as female predominance and the age of onset in the fifth decade of life. Indeed, novel insights into the pathogenesis of the diseases have been obtained in recent years, including a better definition of the role of B and T cells, particularly Th17 cells, and the mechanisms of autoantibody-mediated tissue injury, with anti-mitochondrial antibodies and SS-A/SS-B being identified as specific for primary biliary cholangitis and Sjögren's syndrome, respectively. These findings have opened the possibility to new targeted therapies, but most clinical needs remain unmet, particularly from a therapeutic standpoint where options diverge, with bile acids being the predominant treatment strategy in primary biliary cholangitis and immunomodulators being used to treat Sjögren's syndrome. Here we provide a comprehensive review of the most recent findings on the pathogenesis, clinical manifestations and therapeutic options for Sjögren's syndrome and primary biliary cholangitis, respectively, while stressing the common traits between these conditions. Our cumulative hypothesis is that similarities outnumber differences and that this may prove advantageous towards a better management of patients.

Primary Biliary Cholangitis: Disease Pathogenesis and Implications for Established and Novel Therapeutics

Primary Biliary Cholangitis is a progressive, autoimmune cholestatic liver disorder. Cholestasis with disease progression may lead to dyslipidemia, osteodystrophy and fat-soluble vitamin deficiency. Portal hypertension may develop prior to advanced stages of fibrosis. Untreated disease may lead to cirrhosis, hepatocellular cancer and need for orthotopic liver transplantation. Classically, diagnosis is made with elevation of alkaline phosphatase, demonstration of circulating antimitochondrial antibody, and if performed: asymmetric destruction/nonsupperative cholangitis of intralobular bile ducts on biopsy. Disease pathogenesis is complex and results from innate and adaptive (cell-mediated and humoral) responses that lead to inflammation of biliary duct epithelium. Ongoing damage is amplified and sustained through bile acid toxicity. Use of weight based (13-15mg/kg) ursodeoxycholic acid is well established in retarding disease progression and improving survival; however, is ineffective in achieving complete biochemical remission in many. Recently, a Farnesoid X Receptor agonist, obeticholic acid, has been approved for use. A number of ongoing clinical studies are underway to evaluate utility of fibric acid derivatives, biologics, antifibrotics, and stem cells as monotherapy or in combination with ursodeoxycholic acid for primary biliary cholangitis. The aim of this review is to discuss disease pathogenesis and highlight rationale/implications for both established and novel therapeutics.