Characterization and treatment of persistent hepatocellular secretory failure

Hepatitis E virus infection-triggered intrahepatic cholestasis: A case report

BACKGROUND

Genetic disorders affecting hepatobiliary transporters can be triggered by various factors, resulting in marked cholestasis.

CASE SUMMARY

We report two patients who experienced a severe episode of intrahepatic cholestasis triggered by an acute hepatitis E virus infection. Following an extensive clinical examination that ruled out common causes of cholestatic liver damage, we conducted next-generation sequencing to determine the genetic profiles of the patients. The analysis revealed several known and unknown variants in genes associated with hepatobiliary transporters and bile salt regulation, including ATP8B1, ABCB11, ABCB4, MYO5B, and FXR. For a comprehensive understanding of the pathophysiology, we performed ClinVar analysis and utilized PolyPhen for bioinformatic prediction of functional impact. Both patients exhibited rapid symptom improvement and a decrease in hyperbilirubinemia when treated with either rifampicin or bezafibrate.

CONCLUSION

Our findings introduce hepatitis E viral infection as a novel trigger for intrahepatic cholestasis, and we categorize the significance of the various genetic variants based on the current state of research.

Persistent hepatocyte secretory failure in lopinavir/ritonavir related to drug-induced liver injury: a case report

Lopinavir/ritonavir, an anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) drug, may be associated with the development of liver injury. In this paper, we reported an elderly female patient with drug-induced liver injury secondary to lopinavir/ritonavir, which was evaluated for their causality using the updated Roussel Uclaf Causality Assessment Method (RUCAM) of 2016. She had a RUCAM score of 8 which was equivalent to a probable causality grading. Her clinical course was complicated by persistent hepatocyte secretion failure (PHSF), followed by septic shock and SARS-CoV-2 re-infection during her hospitalization. Her response to any medical intervention, including ursodeoxycholic acid, glutathione, methylprednisolone sodium succinate, rifampicin, artificial liver support, and endoscopic nasobiliary drainage (ENBD) was very poor, and her family members refused liver transplantation. Finally, she died. In summary, this case suggests the possibility that lopinavir/ritonavir can cause DILI and even PHSF in our clinical practice.

Cyclosporine-A induced cytotoxicity within HepG2 cells by inhibiting PXR mediated CYP3A4/CYP3A5/MRP2 pathway

Cyclosporine-A (CsA) is currently used to treat immune rejection after organ transplantation as a commonly used immunosuppressant. Liver injury is one of the most common adverse effects of CsA, whose precise mechanism has not been fully elucidated. Pregnane X receptor (PXR) plays a critical role in mediating drug-induced liver injury as a key regulator of drug and xenobiotic clearance. As a nuclear receptor, PXR transcriptionally upregulates the expression of drug-metabolizing enzymes and drug transporters, including cytochrome P4503A (CPY3A) and multidrug resistance-associated protein 2 (MRP2). Our study established CsA-induced cytotoxic hepatocytes in an in vitro model, demonstrating that CsA dose-dependently increased the aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) level secreted in the HepG2 cell supernatant, as well as viability and oxidative stress of HepG2 cells. CsA also dose-dependently decreased the PXR, CYP3A4, CPY3A5, and MRP2 levels of HepG2 cells. Mechanistically, altering the expression of PXR, CYP3A4, CYP3A5, and MRP2 affected the impact of CsA on AST and LDH levels. Moreover, altering the expression of PXR also changed the level of CYP3A4, CPY3A5, and MRP2 of HepG2 cells treated by CsA. Our presented findings provide experimental evidence that CsA-induced liver injury is PXR tightly related. We suggest that PXR represents an attractive target for therapy of liver injury due to its central role in the regulation of the metabolizing enzymes CYP3A and MRP2-mediated bile acid transport and detoxification.

Identifying chemicals based on receptor binding/bioactivation/mechanistic explanation associated with potential to elicit hepatotoxicity and to support structure activity relationship-based read-across

The liver is the most common target organ in toxicology studies. The development of chemical structural alerts for identifying hepatotoxicity will play an important role in in silico model prediction and help strengthen the identification of analogs used in structure activity relationship (SAR)- based read-across. The aim of the current study is development of an SAR-based expert-system decision tree for screening of hepatotoxicants across a wide range of chemistry space and proposed modes of action for clustering of chemicals using defined core chemical categories based on receptor-binding or bioactivation. The decision tree is based on ∼ 1180 different chemicals that were reviewed for hepatotoxicity information. Knowledge of chemical receptor binding, metabolism and mechanistic information were used to group these chemicals into 16 different categories and 102 subcategories: four categories describe binders to 9 different receptors, 11 categories are associated with possible reactive metabolites (RMs) and there is one miscellaneous category. Each chemical subcategory has been associated with possible modes of action (MOAs) or similar key structural features. This decision tree can help to screen potential liver toxicants associated with core structural alerts of receptor binding and/or RMs and be used as a component of weight of evidence decisions based on SAR read-across, and to fill data gaps.

A historical review of jaundice: May the golden oriole live forever

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Case Report: A Rare Heterozygous ATP8B1 Mutation in a BRIC1 Patient: Haploinsufficiency?

Benign recurrent intrahepatic cholestasis (BRIC) is an autosomal recessive disorder characterized by recurrent cholestasis. ATPase class I, type 8B, member 1 (ATP8B1) encodes familial intrahepatic cholestasis 1 (FIC1), which acts as a phosphatidylserine reversing enzyme in the tubule membrane of hepatocytes to mediate the inward translocation of phosphatidylserine (PS). At present, dozens of ATP8B1 pathogenic mutations have been identified that mainly cause BRIC1 and progressive familial intrahepatic cholestasis 1 (PFIC1). The diagnosis of BRIC1 is based on symptoms, laboratory tests, imaging, liver histology, and genetic testing. BRIC1 treatment seeks to prevent recurrence and reduce disease severity. At present, the main treatment methods include ursodeoxycholic acid (UDCA), rifampin, cholestyramine and haemofiltration, and endoscopic nasobiliary drainage (ENBD). Here, we report a 17-year-old patient with cholestasis who has a rare heterozygous ATP8B1 gene mutation (p.T888K). The patient was treated with UDCA, glucocorticoids and haemofiltration, after which bilirubin levels gradually returned to normal. This case was thought to be caused by an ATP8B1 heterozygous mutation, which may be related to haploinsufficiency (HI).

Natural product-based screening led to the discovery of a novel PXR agonist with anti-cholestasis activity

Cholestasis is a major cause of a series of bile flow malfunction-related liver diseases. Pregnane X receptor (PXR) is a key regulator in endo- and xeno-biotics metabolism, which has been considered as a promising therapeutic target for cholestasis. In this study we conducted human PXR (hPXR) agonistic screening using dual-luciferase reporter gene assays, which led to discovering a series of potent hPXR agonists from a small Euphorbiaceae diterpenoid library, containing 35 structurally diverse diterpenoids with eight different skeleton types. The most active compound 6, a lathyrane diterpenoid (5/11/3 ring system), dose-dependently activated hPXR with a high selectivity, and significantly upregulated the expression of hPXR downstream genes CYP3A4 and UGT1A1. In LCA-induced cholestasis mouse model, administration of compound 6 (50 mg· kg^-1. d^-1, ip) for 7 days significantly suppressed liver necrosis and decreased serum levels of AST, ALT, Tbili, ALP, and TBA, ameliorating LCA-induced cholestatic liver injury. We further revealed that compound 6 exerted its anti-cholestatic efficacy via activation of PXR pathway, accelerating the detoxification of toxic BAs and promoting liver regeneration. These results suggest that lathyrane diterpenoids may serve as a promising scaffold for future development of anti-cholestasis drugs.

Efficacy and safety of rifampicin in patients with persistent hepatocellular secretory failure

BACKGROUND AND AIM

Persistent hepatocellular secretory failure (PHSF) is a rare condition of severe cholestasis caused by drugs, toxins, infection, or temporary biliary obstruction. Real-world data on rifampicin in cholestasis, particularly among patients with deep jaundice, are scarce. We aimed to expand the knowledge on the efficacy and safety of rifampicin treatment in PHSF patients.

METHODS

Sixteen patients with PHSF who had received rifampicin treatment (150-300 mg/d) at our institution from September 2016 to July 2020 were included. Treatment efficacy was assessed by 20% improvement in serum total bilirubin (TBIL) concentration at 4 weeks. Follow-up was continued until the concentration of TBIL returned to normal.

RESULTS

Among the 16 enrolled patients, 12 had predisposing factors (drugs, infection, or transient biliary obstruction). ATP8B1 or ABCB11 mutations were detected in the other four patients without trigger events. UGT1A1 mutations were found in 7/10 patients. Before rifampicin treatment, the median TBIL level was 352 μmol/L (range 171-591 μmol/L). TBIL > 20% improvement was observed in 14 patients at 4 weeks. TBIL levels of 14 patients eventually returned to normal after 6-12 weeks of rifampicin treatment. The remaining two patients who did not respond to rifampicin finally recovered after nasobiliary drainage. Except for one patient with transient drug-induced hepatitis, no other serious adverse events were observed.

CONCLUSIONS

Rifampicin could be a promising option for most PHSF patients. Most PHSF patients have UGT1A1 deficiency, which may be the target of rifampicin.

Lathyrane Diterpenoids as Novel hPXR Agonists: Isolation, Structural Modification, and Structure-Activity Relationships

Pregnane X receptor (PXR) that orchestrates the intricate network of xeno- and endobiotic metabolism is considered as a promising therapeutic target for cholestasis. In this study, the human PXR (hPXR) agonistic bioassay-guided isolation of Euphorbia lathyris followed by the structural modification led to the construction of a lathyrane diterpenoid library (1-34). Subsequent assay of this library led to the identification of a series of potent hPXR agonists, showing better efficacy than that of typical hPXR agonist, rifampicin. The most active compound, 8, could dose-dependently activate hPXR at micromolar concentrations and significantly up-regulate the expressions of PXR downstream genes CYP3A4, CYP2B6, and MDR1. The structure-activity relationships (SARs) studied in combination with molecular modeling suggested that acyloxy at C-7 and the presence of 14-carbonyl were essential to the activity. These findings suggested that lathyrane diterpenoids could serve as a new type of hPXR agonist for future anticholestasis drug development.

Carriers of ABCB4 gene variants show a mild clinical course, but impaired quality of life and limited risk for cholangiocarcinoma

BACKGROUND AND AIMS

Adenosine triphosphate-binding cassette subfamily B member 4 (ABCB4) deficiency may lead to progressive familial intrahepatic cholestasis type 3 (PFIC3), biliary cirrhosis, low phospholipid-associated cholelithiasis (LPAC), intrahepatic cholestasis of pregnancy (ICP), oral contraceptive-induced cholestasis (CIC) or may remain asymptomatic. The long-term course, quality of life and histology were investigated in ABCB4 deficiency.

METHODS

Adult carriers of ABCB4 gene variants from two regional academic centres were analysed by history taking, electronic patient files, physical examination, blood analysis, abdominal ultrasound (US) and liver elastography. Patients completed a 36-Item Short Form Health Survey (SF-36) for quality of life and a Visual Analogue Scale (VAS) for pruritus. Available liver specimens were re-classified according to the Nakanuma scoring system, so far validated for primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) only. Quality of life data were compared to published data of patients with PBC, PSC and the general population.

RESULTS

Sixty-seven patients were identified, 64 (96%) were alive at the time of analysis and 62 (93%) were (at some time) treated with ursodeoxycholic acid (UDCA). Two patients died of cholangiocarcinoma (CCA), and one of decompensated biliary cirrhosis. Three additional deaths of CCA were reported in first-degree relatives. Transplant-free survival was 91% (median follow-up 14 years). Liver stiffness was normal (<6.3 kPa) in 75%, intrahepatic stones were detected at ultrasound (US) in 33% and microcalcifications in 22% of cases. Quality of life (n = 48) was lower than in the general population particularly in energy/fatigue and general health domains and comparable to that in PSC. Staging according to Nakanuma in 15 specimens reflected the clinical course.

CONCLUSIONS

ABCB4 deficiency has a mild clinical course, but impaired quality of life and limited risk of CCA. The Nakanuma scoring system appears feasible for histological evaluation in ABCB4 deficiency.

Mechanism of Hydrophobic Bile Acid-Induced Hepatocyte Injury and Drug Discovery

Cholestatic liver disease is caused by the obstruction of bile synthesis, transport, and excretion in or outside the liver by a variety of reasons. Long-term persistent cholestasis in the liver can trigger inflammation, necrosis, or apoptosis of hepatocytes. Bile acid nuclear receptors have received the most attention for the treatment of cholestasis, while the drug development for bile acid nuclear receptors has made considerable progress. However, the targets regulated by bile acid receptor drugs are limited. Thus, as anticipated, intervention in the expression of bile acid nuclear receptors alone will not yield satisfactory clinical results. Therefore, this review comprehensively summarized the literature related to cholestasis, analyzed the molecular mechanism that bile acid damages cells, and status of drug development. It is hoped that this review will provide some reference for the research and development of drugs for cholestasis treatment in the future.

Mechanism of Hydrophobic Bile Acid-Induced Hepatocyte Injury and Drug Discovery

Cholestatic liver disease is caused by the obstruction of bile synthesis, transport, and excretion in or outside the liver by a variety of reasons. Long-term persistent cholestasis in the liver can trigger inflammation, necrosis, or apoptosis of hepatocytes. Bile acid nuclear receptors have received the most attention for the treatment of cholestasis, while the drug development for bile acid nuclear receptors has made considerable progress. However, the targets regulated by bile acid receptor drugs are limited. Thus, as anticipated, intervention in the expression of bile acid nuclear receptors alone will not yield satisfactory clinical results. Therefore, this review comprehensively summarized the literature related to cholestasis, analyzed the molecular mechanism that bile acid damages cells, and status of drug development. It is hoped that this review will provide some reference for the research and development of drugs for cholestasis treatment in the future.

ABCB4/MDR3 in health and disease – at the crossroads of biochemistry and medicine

Several ABC transporters of the human liver are responsible for the secretion of bile salts, lipids and cholesterol. Their interplay protects the biliary tree from the harsh detergent activity of bile salts. Among these transporters, ABCB4 is essential for the translocation of phosphatidylcholine (PC) lipids from the inner to the outer leaflet of the canalicular membrane of hepatocytes. ABCB4 deficiency can result in altered PC to bile salt ratios, which led to intrahepatic cholestasis of pregnancy, low phospholipid associated cholelithiasis, drug induced liver injury or even progressive familial intrahepatic cholestasis type 3. Although PC lipids only account for 30–40% of the lipids in the canalicular membrane, 95% of all phospholipids in bile are PC lipids. We discuss this discrepancy in the light of PC synthesis and bile salts favoring certain lipids. Nevertheless, the in vivo extraction of PC lipids from the outer leaflet of the canalicular membrane by bile salts should be considered as a separate step in bile formation. Therefore, methods to characterize disease causing ABCB4 mutations should be considered carefully, but such an analysis represents a crucial point in understanding the currently unknown transport mechanism of this ABC transporter.

Cholestasis in the Baby and Infant

Cholestasis in children is a serious condition due to various aetiologic factors. If children with jaundice present with acholic stool, dark urine colour, or direct hyperbilirubinaemia, the patient should be evaluated urgently. Early and timely diagnosis and initiation of appropriate treatment are extremely important determinants of morbidity and mortality. In the neonatal period, idiopathic neonatal cholestasis, alpha-1 antitrypsin deficiency, cholestasis from infections, and biliary atresia are the most common causes of cholestasis. Nowadays, with the development of genetic and molecular biological studies, the diagnosis of many diseases that have previously been evaluated as ‘idiopathic‘ can be made. It is the aetiological factor that determines the prognosis. The treatment plan is created in accordance with aetiological causes and in response to symptoms such as pruritus and malabsorption: this can be surgical treatment across a diverse spectrum, from biliary diversion to liver transplantation. In this study, the aetiology, diagnosis, and treatment of cholestasis in babies and infants are reviewed in the light of current literature.

Progressive familial intrahepatic cholestasis: diagnosis, management, and treatment

Progressive familial intrahepatic cholestasis (PFIC) is a group of autosomal recessive cholestatic liver diseases which are subgrouped according to the genetic defect, clinical presentation, laboratory findings and liver histology. Progressive liver fibrosis, cirrhosis, and end stage liver disease (ESLD) may eventually develop. PFIC was first described in Amish descendants of Jacob Byler, therefore it was originally called Byler disease. But it can be seen anywhere on the globe. This review summarizes the main features of the subtypes of the disease and discusses the current available diagnosis, conservative and surgical therapeutic options.

Low risk of hepatotoxicity from rifampicin when used for cholestatic pruritus: a cross-disease cohort study

BACKGROUND

The use of rifampicin for cholestatic pruritus is accompanied by concerns over safety, but the availability of real-world prescribing data is relatively limited.

AIM

We sought to describe the rate and characteristics of rifampicin-induced hepatitis in a mixed aetiology cohort of patients with established liver disease and cholestatic pruritus.

METHODS

Retrospective review of records for out-patients commenced on rifampicin for pruritus 2012-2016 inclusive. Rifampicin-induced hepatitis was recorded where alanine aminotransferase activity (ALT) increased to both ≥5 × baseline and ≥5 × upper limit of normal (ULN), or to both ≥3 × baseline and ≥3 × ULN with concurrent elevation in serum bilirubin to ≥2 × baseline and ≥2 × ULN, in addition to a Roussel-Uclaf Causality Assessment Method score of "probable" or "highly probable" for rifampicin causality.

RESULTS

After exclusions, we reviewed 105 patients who took rifampicin for a median of 131 days. Most had primary biliary cholangitis or primary sclerosing cholangitis; 40 (38.1%) were men and median age was 44 years (IQR: 32-57). 44 (41.9%) patients had baseline serum bilirubin ≥2 × ULN and 28 (26.7%) ALT ≥3 × ULN. 5 (4.8%) developed rifampicin-induced hepatitis at a median of 70(range 27-130) days after drug initiation. No individual or laboratory baseline characteristics were significantly associated with subsequent development of hepatitis. All cases of hepatitis recovered after drug cessation, although one patient was hospitalised and received corticosteroids.

CONCLUSIONS

Given the efficacy of rifampicin for an important sub-group of those with cholestatic pruritus, adult patients, including those with jaundice, can be counselled that 95% of prescriptions are safe, and where hepatitis occurs, including at long latency, drug cessation appears effective.

New therapies target the toxic consequences of cholestatic liver disease

In most cholestatic liver diseases the primary cholestasis-causing lesions are located in the biliary tree and may be of (auto)immune origin. Bile salts are responsible for the secondary toxic consequences. Bile salt and nuclear hormone directed therapies primarily aim at improving this secondary toxic injury. In primary biliary cholangitis, trials show statistically significant responses on biochemical endpoints. Preclinical studies suggest that FXR- and PPAR-agonists, inhibitors of the apical sodium-dependent bile salt transporter (ASBT-inhibitors) and the C₂₃ UDCA derivative nor-UDCA are promising agents for the treatment of primary sclerosing cholangitis (PSC). Area covered: Pharmaceuticals that interfere with bile salt signaling in humans for the treatment of chronic cholestatic liver disease are reviewed. Expert commentary: Nuclear hormone receptors, bile salt transport proteins and receptors provide targets for novel therapies of cholestatic liver disease. These drugs show positive results on biochemical endpoints. For histological endpoints, survival and transplant-free survival, long-term trials are needed. For relief of symptoms, such as fatigue and pruritus, these drugs have yet to prove their value.

Nuclear receptor FXR, bile acids and liver damage: Introducing the progressive familial intrahepatic cholestasis with FXR mutations

The nuclear receptor farnesoid X receptor (FXR) is the master regulator of bile acids (BAs) homeostasis since it transcriptionally drives modulation of BA synthesis, influx, efflux, and detoxification along the enterohepatic axis. Due to its crucial role, FXR alterations are involved in the progression of a plethora of BAs associated inflammatory disorders in the liver and in the gut. The involvement of the FXR pathway in cholestasis development and management has been elucidated so far with a direct role of FXR activating therapy in this condition. However, the recent identification of a new type of genetic progressive familial intrahepatic cholestasis (PFIC) linked to FXR mutations has strengthen also the bona fide beneficial effects of target therapies that by-pass FXR activation, directly promoting the action of its target, namely the enterokine FGF19, in the repression of hepatic BAs synthesis with reduction of total BA levels in the liver and serum, accomplishing one of the major goals in cholestasis. This article is part of a Special Issue entitled: Cholangiocytes in Health and Diseaseedited by Jesus Banales, Marco Marzioni and Peter Jansen.

[Chronic cholestatic liver diseases : Differential diagnosis, pathogenesis and current treatment in adults]

In the long-term course chronic cholestasis regularly leads to fibrotic restructuring and ultimately to functional failure of the liver, independent of the cause. Cholestatic diseases are often clinically asymptomatic. In order to avoid progression, early diagnosis of the underlying disease and a targeted therapy are therefore decisive. The differential diagnoses of chronic cholestasis are broad; therefore, algorithms are of assistance in the diagnostic work-up. A better understanding of the pathogenesis is now leading to the development of new therapeutic agents in addition to ursodeoxycholic acid, which has long been known for its anticholestatic effects. Obeticholic acid and, in the near future, bezafibrate are therapeutic options. The possibilities for genetic diagnostics of unclear cholestasis syndromes improve the understanding of the pathogenesis of many diseases and are being introduced increasingly earlier into the clinical routine.

Liver resection for cancer: New developments in prediction, prevention and management of postresectional liver failure

Hepatic failure is a feared complication that accounts for up to 75% of mortality after extensive liver resection. Despite improved perioperative care, the increasing complexity and extensiveness of surgical interventions, in combination with an expanding number of resections in patients with compromised liver function, still results in an incidence of postresectional liver failure (PLF) of 1-9%. Preventive measures aim to enhance future remnant liver size and function. Numerous non-invasive techniques to assess liver function and predict remnant liver volume are being developed, along with introduction of novel surgical strategies that augment growth of the future remnant liver. Detection of PLF is often too late and treatment is primarily symptomatic. Current therapeutic research focuses on ([bio]artificial) liver function support and regenerative medicine. In this review we discuss the current state and new developments in prediction, prevention and management of PLF, in light of novel insights into the aetiology of this complex syndrome.

LAY SUMMARY

Liver failure is the main cause of death after partial liver resection for cancer, and is presumably caused by an insufficient quantity and function of the liver remnant. Detection of liver failure is often too late, and current treatment focuses on relieve of symptoms. New research initiatives explore artificial support of liver function and stimulation of regrowth of the remnant liver.