Primary biliary cholangitis: treatment

Forsythiaside-A improved bile-duct-ligation-induced liver fibrosis in mice: The involvement of alleviating mitochondrial damage and ferroptosis in hepatocytes via activating Nrf2

Liver fibrosis is a key and reversible stage in the progression of many chronic liver diseases to cirrhosis or hepatocellular carcinoma. Forsythiaside-A (FTA), a main compound isolated from Forsythiae Fructus, has an excellent liver protective activity. This study aims to investigate the efficacy of FTA in improving cholestatic liver fibrosis. Bile-duct-ligation (BDL) was conducted to induce liver fibrosis in mice. Hepatic collagen deposition was evaluated by Masson and Sirus red staining. The bile acid spectrum in the liver and serum was analyzed by mass spectrometry. Liver oxidative stress injury and mitochondria damage were observed by using Mito-Tracker Red fluorescence staining, transmission electron microscopy, etc. The level of ferrous iron (Fe2+) and the expression of ferroptosis-associated molecules were detected. The binding between FTA and its target protein was confirmed by Co-immunoprecipitation (Co-IP), cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS) and surface plasmon resonance (SPR). Our results demonstrated that FTA alleviated BDL-induced liver fibrosis in mice. FTA did not decrease the elevated amount of bile acids in BDL-treated mice, but reduced the bile acid-induced mitochondrial damage, oxidative stress and ferroptosis in hepatocytes, and also induced nuclear factor erythroid 2-related factor-2 (Nrf2) activation. In Nrf2 knock-out mice, the FTA-provided protection against BDL-induced liver fibrosis was disappeared, and FTA's inhibition on mitochondrial damage, oxidative stress and ferroptosis were lowered. Further results displayed that FTA could directly bind to Kelch-like ECH-associated protein-1 (Keap1), thereby activating Nrf2. Moreover, the BDL-induced liver fibrosis was markedly weakened in liver-specific Keap1 knockout mice. Hence, this study suggests that FTA alleviated the BDL-induced liver fibrosis through attenuating mitochondrial damage and ferroptosis in hepatocytes by activating Nrf2 via directly binding to Keap1.

Evaluating the safety and efficacy of seladelpar for adults with primary biliary cholangitis

INTRODUCTION

Seladelpar (MBX-8025) is a once-daily administered highly specific PPAR-δ agonist in Phase 3 and extension trials for use in patients with primary biliary cholangitis (PBC).

AREAS COVERED

This review provides background on current treatment options for PBC, and summarizes clinical trial data regarding the safety and effectiveness of seladelpar within the context of these treatments.

EXPERT OPINION

Clinical trials results demonstrate the safety and tolerability of seladelpar use for PBC, including in patients with cirrhosis. The primary composite endpoint (ALP <1.67 times ULN, decrease ≥ 15% from baseline, and TB ≤ULN) was met in 61.7% of the patients treated with seladelpar and in 20% receiving placebo (p < 0.001). Moreover, pruritus - a cardinal and often intractable symptom of PBC - was improved with seladelpar treatment, as were overall quality of life measurements. Improvements in markers of inflammation were likewise observed. These biochemical and clinical findings therefore represent landmark developments in PBC treatment and offer a therapeutic option for PBC.

Bile Acids as Signaling Molecules: Role of Ursodeoxycholic Acid in Cholestatic Liver Disease

Ursodeoxycholic acid (UDCA) is a natural substance physiologically produced in the liver. Initially used to dissolve gallstones, it is now successfully used in treating primary biliary cirrhosis and as adjuvant therapy for various hepatobiliary cholestatic diseases. However, the mechanisms underlying its beneficial effects still need to be clarified. Evidence suggests three mechanisms of action for UDCA that could benefit humans with cholestatic liver disease (CLD): protection of cholangiocytes against hydrophobic bile acid (BA) cytotoxicity, stimulation of hepatobiliary excretion, and protection of hepatocytes against BA-induced apoptosis. These mechanisms may act individually or together to potentiate them. At the molecular level, it has been observed that UDCA can generate modifications in the transcription and translation of proteins essential in the transport of BA, correcting the deficit in BA secretion in CLD, in addition to activating signaling pathways to translocate these transporters to the sites where they should fulfill their function. Inhibition of BA-induced hepatocyte apoptosis may play a role in CLD, characterized by BA retention in the hepatocyte. Thus, different mechanisms of action contribute to the improvement after UDCA administration in CLD. On the other hand, the effects of UDCA on tissues that possess receptors that may interact with BAs in pathological contexts, such as skeletal muscle, are still unclear. This work aims to describe the main molecular mechanisms by which UDCA acts in the human body, emphasizing the interaction in tissues other than the liver.

Potential Theranostic Roles of SLC4 Molecules in Human Diseases

The solute carrier family 4 (SLC4) is an important protein responsible for the transport of various ions across the cell membrane and mediating diverse physiological functions, such as the ion transporting function, protein-to-protein interactions, and molecular transduction. The deficiencies in SLC4 molecules may cause multisystem disease involving, particularly, the respiratory system, digestive, urinary, endocrine, hematopoietic, and central nervous systems. Currently, there are no effective strategies to treat these diseases. SLC4 proteins are also found to contribute to tumorigenesis and development, and some of them are regarded as therapeutic targets in quite a few clinical trials. This indicates that SLC4 proteins have potential clinical prospects. In view of their functional characteristics, there is a critical need to review the specific functions of bicarbonate transporters, their related diseases, and the involved pathological mechanisms. We summarize the diseases caused by the mutations in SLC4 family genes and briefly introduce the clinical manifestations of these diseases as well as the current treatment strategies. Additionally, we illustrate their roles in terms of the physiology and pathogenesis that has been currently researched, which might be the future therapeutic and diagnostic targets of diseases and a new direction for drug research and development.

Gallstone and Gallbladder Disease: Biliary Tract and Cholangiopathies

Cholestatic liver diseases are named primarily due to the blockage of bile flow and buildup of bile acids in the liver. Cholestasis can occur in cholangiopathies, fatty liver diseases, and during COVID-19 infection. Most literature evaluates damage occurring to the intrahepatic biliary tree during cholestasis; however, there may be associations between liver damage and gallbladder damage. Gallbladder damage can manifest as acute or chronic inflammation, perforation, polyps, cancer, and most commonly gallstones. Considering the gallbladder is an extension of the intrahepatic biliary network, and both tissues are lined by biliary epithelial cells that share common mechanisms and properties, it is worth further evaluation to understand the association between bile duct and gallbladder damage. In this comprehensive article, we discuss background information of the biliary tree and gallbladder, from function, damage, and therapeutic approaches. We then discuss published findings that identify gallbladder disorders in various liver diseases. Lastly, we provide the clinical aspect of gallbladder disorders in liver diseases and ways to enhance diagnostic and therapeutic approaches for congruent diagnosis. © 2023 American Physiological Society. Compr Physiol 13:4909-4943, 2023.

Gut Microbiota and Antibiotic Treatments for the Main Non-Oncologic Hepato-Biliary-Pancreatic Disorders

The gut microbiota is a pivotal actor in the maintenance of the balance in the complex interconnections of hepato-biliary-pancreatic system. It has both metabolic and immunologic functions, with an influence on the homeostasis of the whole organism and on the pathogenesis of a wide range of diseases, from non-neoplastic ones to tumorigenesis. The continuous bidirectional metabolic communication between gut and hepato-pancreatic district, through bile ducts and portal vein, leads to a continuous interaction with translocated bacteria and their products. Chronic liver disease and pancreatic disorders can lead to reduced intestinal motility, decreased bile acid synthesis and intestinal immune dysfunction, determining a compositional and functional imbalance in gut microbiota (dysbiosis), with potentially harmful consequences on the host's health. The modulation of the gut microbiota by antibiotics represents a pioneering challenge with striking future therapeutic opportunities, even in non-infectious diseases. In this setting, antibiotics are aimed at harmonizing gut microbial function and, sometimes, composition. A more targeted and specific approach should be the goal to pursue in the future, tailoring the treatment according to the type of microbiota modulation to be achieved and using combined strategies.

Cholestatic Pruritus in Children: Conventional Therapies and Beyond

Pruritus in the setting of cholestatic liver disease is difficult to treat and occurs in patients ranging in age from infancy to adulthood. Likely multifactorial in etiology, this symptom often involves multimodal therapy targeting several pathways and mechanisms proposed in the underlying etiology of cholestatic pruritus. Many patients in both the pediatric and adult populations continue to experience unrelenting pruritus despite maximal conventional therapy. Options are further limited in treating pediatric patients due to sparse data regarding medication safety and efficacy in younger patients. Conventional therapies for the treatment of cholestatic pruritus in children include ursodeoxycholic acid, cholestyramine, hydroxyzine, and rifampin. Certain therapies are more routinely used in the adult populations but with limited data available for use in child and adolescent patients, including opioid antagonists and selective serotonin reuptake inhibitors. Recently, ileal bile acid transport inhibitors have been shown to alleviate pruritus in many children with Alagille syndrome and progressive familial intrahepatic cholestasis and is an additional therapy available for consideration for these patients. Ultimately, surgical options such as biliary diversion or liver transplantation are considered in specific circumstances when medical therapies have been exhausted and pruritus remains debilitating. While further investigation regarding underlying etiologies and effective therapies are needed to better understand itch pathogenesis and treatment in pediatric cholestasis, current considerations beyond conventional management include the use of opioid antagonists, selective serotonin reuptake inhibitors, ileal bile acid transport inhibitors, and surgical intervention.

Selected Aspects of the Intricate Background of Immune-Related Cholangiopathies-A Critical Overview

Primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) are rare immune-related cholangiopathies with still poorly explained pathogenesis. Although triggers of chronic inflammation with subsequent fibrosis that affect cholangiocytes leading to obliteration of bile ducts and conversion to liver cirrhosis are unclear, both disorders are regarded to be multifactorial. Different factors can contribute to the development of hepatocellular injury in the course of progressive cholestasis, including (1) body accumulation of bile acids and their toxicity, (2) decreased food intake and nutrient absorption, (3) gut microbiota transformation, and (4) reorganized host metabolism. Growing evidence suggests that intestinal microbiome composition not only can be altered by liver dysfunction, but in turn, it actively impacts hepatic conditions. In this review, we highlight the role of key factors such as the gut-liver axis, intestinal barrier integrity, bile acid synthesis and circulation, and microbiome composition, which seem to be strongly related to PBC and PSC outcome. Emerging treatments and future therapeutic strategies are also presented.

New IMB16-4 Hot-Melt Extrusion Preparation Improved Oral Bioavailability and Enhanced Anti-Cholestatic Effect on Rats

Background

Cholestasis is challenging to treat due to lacked effective drugs. N-(3,4,5-trichlorophenyl)-2 (3-nitrobenzenesulfonamido) benzamide, abbreviated as IMB16-4, which may be effective for the treatment of cholestasis. However, its poor solubility and bioavailability seriously obstruct the research programs.

Methods

A hot-melt extrusion (HME) preparation was first applied to increase the bioavailability of IMB16-4, the oral bioavailability, anti-cholestatic effect and vitro cytotoxicity of IMB16-4 and IMB16-4-HME were evaluated. Meanwhile, the molecular docking and qRT-PCR were used to validate the mechanism behind.

Results

The oral bioavailability of IMB16-4-HME improved 65-fold compared with that of pure IMB16-4. Pharmacodynamics results demonstrated that IMB16-4-HME prominently decreased the serum levels of total bile acid (TBA) and alkaline phosphatase (ALP), but elevated the level of total bilirubin (TBIL) and direct bilirubin (DBIL). Histopathology revealed that IMB16-4-HME at lower dose exhibited stronger anti-cholestatic effect compared with pure IMB16-4. In addition, molecular docking demonstrated that IMB16-4 has great affinity with PPARα, and qRT-PCR results revealed that IMB16-4-HME significantly elevated the mRNA expression level of PPARα, but decreased the mRNA level of CYP7A1. Cytotoxicity assays demonstrated that the hepatotoxicity of IMB16-4-HME was absolutely attributed to IMB16-4, and the excipients of IMB16-4-HME may increase the drug load within HepG2 cells.

Conclusion

The HME preparation significantly increased the oral bioavailability and anti-cholestatic effect of pure IMB16-4, but caused liver injury at high dose, which require a dose balance between the curative effect and safety in the future research.

Fenofibrate improves GLOBE and UK-PBC scores and histological features in primary biliary cholangitis

BACKGROUND

Fenofibrate (FF) has been suggested as a second-line therapy for primary biliary cholangitis (PBC) with suboptimal response to ursodeoxycholic acid (UDCA). But its long-term effect is unclear.

METHODS

From a retrospective cohort (N.=838), we enrolled 106 UDCA-refractory PBC patients, among them 62 received UDCA monotherapy (UDCA group) and 44 received FF combined with UDCA (UDCA+FF group). Changes of liver biochemistries and prognosis after treatment were determined. In addition, sequential liver biopsies were used to assess the effect of FF on histological parameters.

RESULTS

We found adding FF could significantly reduce serum levels of alkaline phosphatase (ALP), but for patients with pretreatment ALP≥1.67 upper limit of normal (ULN), the significant decline of serum ALP was only observed in the UDCA+FF group after 1 year of therapy. The mean GLOBE Score and the liver transplant-free survival predicted by GLOBE Score were both improved significantly in patients receiving UDCA+FF after 1 year of therapy. The liver-related death or liver transplant calculated using UK-PBC risk score was significantly reduced in patients receiving UDCA+FF after 1 year of therapy. Although there was no marked difference in the final histological analysis after 3 years of therapy, patients receiving UDCA+FF had improvements or stabilization in fibrosis (85.7%), and bile duct loss (78.6%) were more than that of patients receiving UDCA (70.6% and 76.5%, respectively).

CONCLUSIONS

Adding FF improves GLOBE and UK-PBC scores and is also associated with the improvements or stabilization of disease features, including fibrosis and ductular injury.

Incomplete response to ursodeoxycholic acid in primary biliary cholangitis: criteria, epidemiology, and possible mechanisms

INTRODUCTION

As a common autoimmune disease with the characteristic of early complication, primary biliary cholangitis (PBC) leads to an increasing number of mortalities among people with end-stage liver disease (ESLD) waiting for liver transplantation. Ursodeoxycholic acid (UDCA) is the only approved first-line medicine for PBC, and a good response to treatment could acquire an ideal prognosis. Patients with poor UDCA response usually have more adverse outcomes and worse survival, therefore, the management of this group become a major consideration.

AREAS COVERED

Due to the complexity of race and environment for PBC, different criteria for UDCA response exhibit various predictive performances. Factors affecting UDCA response conditions include gender, age, ethnicity, serum indicators, auto-antibodies, and autoimmune comorbidities, while no agreement has been reached. In this review, we mainly focus on cellular senescence, immune-mediated damage, and vitamin D deficiency as possible mechanisms for UDCA non-responders.

EXPERT OPINION

The pathogenesis of PBC has yet to be clarified. Immunology-related mechanisms and therapy targets ought to be the main effort made for further study. Irrespective of the response condition, UDCA is recommended for routine administration in all PBC patients without contraindication. Ongoing clinical trials of second-line and additional therapy exhibit promising prospects.

Novel Therapies in Primary Biliary Cholangitis: What Is in the Pipeline?

Primary biliary cholangitis is a chronic autoimmune disease characterized by inflammation and the progressive destruction of small intrahepatic bile ducts. Current first-line treatment includes ursodeoxycholic acid; however, a significant number of patients have an inadequate response to therapy. These patients are at risk of liver failure requiring liver transplantation and experience a poor quality of life due to refractory symptoms. This manuscript aims to shed light on the current and prospective treatment options that may slow disease progression and improve these patients' symptoms.

Prediction and evaluation of high-risk patients with primary biliary cholangitis receiving ursodeoxycholic acid therapy: an early criterion

BACKGROUND AND AIMS

Current treatment guidelines recommend ursodeoxycholic acid (UDCA) as the first-line treatment for new-diagnosed primary biliary cholangitis (PBC) patients. However, up to 40% patients are insensitive to UDCA monotherapy, and evaluation of UDCA response at 12 months may result in long period of ineffective treatment. We aimed to develop a new criterion to reliably identify non-response patients much earlier.

METHODS

Five hundred sixty-nine patients with an average of 59 months (Median: 53; IQR:32-79) follow-up periods were randomly divided into either the training (70%) or the validation cohort (30%). The efficiency of different combinations of total bilirubin (TBIL), alkaline phosphatase (ALP), and aspartate aminotransferase (AST) threshold values to predict outcomes was assessed at 1, 3 or 6 month after the initiation of UDCA therapy. The endpoints were defined as adverse outcomes, including liver-related death, liver transplantation and complications of cirrhosis. Adverse outcome-free survival was compared using various published criteria and a proposed new criterion.

RESULTS

A new criterion of evaluating UDCA responses at 1 month was established as: ALP ≤ 2.5 × upper limit of normal (ULN) and AST ≤ 2 × ULN, and TBIL ≤ 1 × ULN (Xi'an criterion). The 5 year adverse outcome-free survival rate of UDCA responders, defined by Xi'an criterion, was 97%, which was significantly higher than that of those non-responders (64%). An accurate distinguishing high-risk patients' capacity of Xi'an criterion was confirmed in both early and late-stage PBC.

CONCLUSIONS

Xi'an criterion has a similar or even higher ability to distinguish high-risk PBC patients than other published criteria. Xi'an criterion can facilitate early identification of patients requiring new therapeutic approaches.

Obeticholic Acid Improves Aminotransferases Early during Treatment in Patients with Primary Biliary Cholangitis Not Responding to Ursodeoxycholic Acid: A Study in Clinical Practice

Obeticholic acid (OCA) improves cholestasis and is generally well tolerated in patients with primary biliary cholangitis (PBC) not responding, or intolerant, to ursodeoxycholic acid (UDCA). As PBC is mainly a cholestatic disorder, less attention is paid to aminotransferase behavior in the course of treatment. In this study we evaluated, in clinical practice, the efficacy of OCA treatment on both alkaline phosphatase (ALP) and alanine aminotransferase (ALT) using updated healthy ranges for aminotransferases. Fifteen PBC patients, non-responders to UDCA, were evaluated at baseline and during OCA treatment with serial measurement of cholestasis indexes and ALT, that were also assessed using updated normal ranges (<30 IU/L in males, <19 IU/L in females). Median ALP and ALT decreased from 2.16 to 1.27 × upper limit of normal (p = 0.003) and from 0.93 to 0.78 × upper limit of normal (p = 0.008), respectively, in the course of OCA treatment. At treatment day-15, median ALT decreased by 29.7% and ALP by 8.8%. Bilirubin and albumin were unmodified throughout treatment. Using updated normal ranges, ALT levels were normal in 6.7% of patients at baseline and in 33.3% of patients at 18 months of treatment. OCA treatment improves cholestasis and, also, indexes of hepatocyte necrosis, with a decline in necro-inflammatory activity even predating the improvement in cholestasis. Use of recalibrated healthy ranges for aminotransferases might be a useful tool to assess hepatic histological activity and its improvement with OCA treatment.