Severe cholestasis may result in end-stage liver disease with the need of liver transplantation (LTX). In children, about 10 % of LTX are necessary because of cholestatic liver diseases. Apart from ...bile duct atresia, three types of progressive familial intrahepatic cholestasis (PFIC) are common causes of severe cholestasis in children. The three subtypes of PFIC are defined by the involved genes: PFIC-1, PFIC-2, and PFIC-3 are due to mutations of P-type ATPase
ATP8B1
(familial intrahepatic cholestasis 1, FIC1), the ATP binding cassette transporter
ABCB11
(bile salt export pump, BSEP), or
ABCB4
(multidrug resistance protein 3, MDR3), respectively. All transporters are localized in the canalicular membrane of hepatocytes and together mediate bile salt and phospholipid transport. In some patients with PFIC-2 disease, recurrence has been observed after LTX, which mimics a PFIC phenotype. It could be shown by several groups that inhibitory anti-BSEP antibodies emerge, which most likely cause disease recurrence. The prevalence of severe BSEP mutations (e.g., splice site and premature stop codon mutations) is very high in this group of patients. These mutations often result in the complete absence of BSEP, which likely accounts for an insufficient auto-tolerance against BSEP. Although many aspects of this “new” disease are not fully elucidated, the possibility of anti-BSEP antibody formation has implications for the pre- and posttransplant management of PFIC-2 patients. This review will summarize the current knowledge including diagnosis, pathomechanisms, and management of “autoimmune BSEP disease.”
Intrahepatic cholestasis of pregnancy (ICP) is a common disease affecting up to 5% of pregnancies and which can cause fetal arrhythmia and sudden intrauterine death. We previously demonstrated that ...bile acid taurocholate (TC), which is raised in the bloodstream of ICP, can acutely alter the rate and rhythm of contraction and induce abnormal calcium destabilization in cultured neonatal rat cardiomyocytes (NRCM). Apart from their hepatic functions bile acids are ubiquitous signalling molecules with diverse systemic effects mediated by either the nuclear receptor FXR or by a recently discovered G-protein coupled receptor TGR5. We aim to investigate the mechanism of bile-acid induced arrhythmogenic effects in an in-vitro model of the fetal heart.
Levels of bile acid transporters and nuclear receptor FXR were studied by quantitative real time PCR, western blot and immunostaining, which showed low levels of expression. We did not observe functional involvement of the canonical receptors FXR and TGR5. Instead, we found that TC binds to the muscarinic M(2) receptor in NRCM and serves as a partial agonist of this receptor in terms of inhibitory effect on intracellular cAMP and negative chronotropic response. Pharmacological inhibition and siRNA-knockdown of the M(2) receptor completely abolished the negative effect of TC on contraction, calcium transient amplitude and synchronisation in NRCM clusters.
We conclude that in NRCM the TC-induced arrhythmia is mediated by the partial agonism at the M(2) receptor. This mechanism might serve as a promising new therapeutic target for fetal arrhythmia.
Progressive familial intrahepatic cholestasis type 2 (PFIC‐2) is caused by mutations in ABCB11, encoding the bile salt export pump (BSEP). In 2009, we described a child with PFIC‐2 who developed ...PFIC‐like symptoms after orthotopic liver transplantation (OLT). BSEP‐reactive antibodies were demonstrated to account for disease recurrence. Here, we characterize the nature of this antibody response in 7 more patients with antibody‐induced BSEP deficiency (AIBD). Gene sequencing and immunostaining of native liver biopsies indicated absent or strongly reduced BSEP expression in all 7 PFIC‐2 patients who suffered from phenotypic disease recurrence post‐OLT. Immunofluorescence, western blotting analysis, and transepithelial transport assays demonstrated immunoglobulin (Ig) G‐class BSEP‐reactive antibodies in these patients. In all cases, the N‐terminal half of BSEP was recognized, with reaction against its first extracellular loop (ECL1) in six sera. In five, antibodies reactive against the C‐terminal half also were found. Only the sera recognizing ECL1 showed inhibition of transepithelial taurocholate transport. In a vesicle‐based functional assay, transport inhibition by anti‐BSEP antibodies binding from the cytosolic side was functionally proven as well. Within 2 hours of perfusion with antibodies purified from 1 patient, rat liver showed canalicular IgG staining that was absent after perfusion with control IgG. Conclusions: PFIC‐2 patients carrying severe BSEP mutations are at risk of developing BSEP antibodies post‐OLT. The antibody response is polyclonal, targeting both extra‐ and intracellular BSEP domains. ECL1, a unique domain of BSEP, likely is a critical target involved in transport inhibition as demonstrated in several patients with AIBD manifest as cholestasis. (Hepatology 2016;63:524–537)
Background
The adjacent conditions infection, sepsis, and septic shock are among the most common causes of treatment in the emergency department (ED). Most available data come from intensive care ...units (ICU) and include nosocomial infections acquired during hospitalization. Epidemiological data from German EDs are not yet available, although the ED is one of the first points of contact for patients. The aim of this study was to investigate the epidemiology, causes, diagnosis, mortality, and treatment of patients with infections in the ED.
Materials and methods
In this retrospective, single-center observational study, routinely collected data from the patient data management system and from the hospital information system were analyzed. All adult patients who presented to the ED in connection with an infection during the study period from 01/01 to 28/02/2019 were included. Exclusion criteria were age ≤ 17 years and incomplete records. Three groups (I. Infection, II. Sepsis, and III. Septic shock) were defined according to SEPSIS-3 definitions.
Results
During the study period, a total of 6,607 patients were treated in the ED. Of these patients, 19.3% (
n
= 1,278) had an infection (mean age 56 ± 23 years, 50% female). The sites of infection were distributed as follows: Respiratory tract 35%, genitourinary tract 18%, maxillofacial/ears/nose/throat 14%, intraabdominal 13%, soft tissues 10%, central nervous system 1%, other cause 3%, or unknown cause 6%. Infection only, sepsis and septic shock were present in 86, 10, and 3%, respectively. There were significant differences in vital signs as well as in the various emergency sepsis scores across the predefined groups I vs. II vs. III: SOFA (pts.): 1 ± 1 vs. 4 ± 2 vs. 7 ± 3 (
p
< 0.0001), systolic blood pressure (mmHg): 137 ± 25 vs. 128 ± 32 vs. 107 ± 34 (
p
< 0.05), heart rate (bpm): 92 ± 18 vs. 99 ± 23 vs. 113 ± 30 (
p
< 0.05), respiratory rate (min-1): 18 ± 4 vs. 20 ± 7 vs. 24 ± 10 (
p
< 0.05). In the three groups, blood cultures were obtained in 34, 81, and 86%, of cases, respectively and antibiotics were administered in the ED in 50, 89, and 86%, of cases respectively. The 30-day mortality rate in the three groups was 1.6, 12.0, and 38.1%, respectively.
Conclusion
This study is the first to show the incidence, management, and outcome of patients classified as infection, sepsis, and septic shock in a German ED. The findings of our real-world data are important for quality management and enable the optimization of treatment pathways for patients with infectious diseases.
TGR5 (Gpbar1) is a G protein-coupled receptor responsive to bile acids (BAs), which is expressed in different non-parenchymal cells of the liver, including biliary epithelial cells, liver-resident ...macrophages, sinusoidal endothelial cells (LSECs), and activated hepatic stellate cells (HSCs). Mice with targeted deletion of TGR5 are more susceptible towards cholestatic liver injury induced by cholic acid-feeding and bile duct ligation, resulting in a reduced proliferative response and increased liver injury. Conjugated lithocholic acid (LCA) represents the most potent TGR5 BA ligand and LCA-feeding has been used as a model to rapidly induce severe cholestatic liver injury in mice. Thus, TGR5 knockout (KO) mice and wildtype (WT) littermates were fed a diet supplemented with 1% LCA for 84 h. Liver injury and gene expression changes induced by the LCA diet revealed an enrichment of pathways associated with inflammation, proliferation, and matrix remodeling. Knockout of TGR5 in mice caused upregulation of endothelin-1 (ET-1) expression in the livers. Analysis of TGR5-dependent ET-1 signaling in isolated LSECs and HSCs demonstrated that TGR5 activation reduces ET-1 expression and secretion from LSECs and triggers internalization of the ET-1 receptor in HSCs, dampening ET-1 responsiveness. Thus, we identified two independent mechanisms by which TGR5 inhibits ET-1 signaling and modulates portal pressure.
Background & Aims: Hydrophobic bile salts trigger a rapid oxidative stress response as an upstream event of CD95 activation and hepatocyte apoptosis.
Methods: The underlying mechanisms were studied ...by Western blot, immunocytochemistry, protein knockdown, and fluorescence resonance energy transfer microscopy in rat hepatocytes and human hepatoma cell line 7 (Huh7).
Results: The rapid oxidative stress formation in response to taurolithocholate-3-sulfate (TLCS) was inhibited by diphenyleneiodonium, apocynin, and neopterin, suggestive for the involvement of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases. TLCS induced a rapid serine phosphorylation of the regulatory subunit p47phox, which was sensitive to inhibition of sphingomyelinase and protein kinase Cζ (PKCζ). Inhibitors of p47phox phosphorylation and p47phox protein knockdown abolished the TLCS-induced oxidative stress response and blunted subsequent CD95 activation. Consequences of TLCS-induced oxidative stress were c-Jun-N-terminal kinase activation and Yes-dependent activation of the epidermal growth factor receptor (EGFR), followed by EGFR-catalyzed CD95 tyrosine phosphorylation, formation of the death-inducing signaling complex, and execution of apoptosis. As shown by fluorescence resonance energy transfer experiments in Huh7 cells, TLCS induced a c-Jun-N-terminal kinase–dependent EGFR/CD95 association in the cytosol and trafficking of this protein complex to the plasma membrane. Inhibition of EGFR tyrosine kinase activity by AG1478 allowed for cytosolic EGFR/CD95 association, but prevented targeting of the EGFR/CD95 complex to the plasma membrane. Both processes, and TLCS-induced Yes and EGFR activation, were sensitive to inhibition of sphingomyelinase, PKCζ, or NADPH oxidases.
Conclusions: The data suggest that hydrophobic bile salts activate NADPH oxidase isoforms with the resulting oxidative stress response triggering activation of the CD95 system and apoptosis.
Atezolizumab plus bevacizumab is the standard of care for first-line systemic therapy for advanced hepatocellular carcinoma (aHCC). Data on the efficacy and safety of atezolizumab plus bevacizumab in ...patients with aHCC who have received prior systemic therapy are not available.
Patients with aHCC who received atezolizumab plus bevacizumab after at least one systemic treatment between December 2018 and March 2022 were retrospectively identified in 13 centers in Germany and Austria. Patient characteristics, tumor response rates, progression-free survival (PFS), overall survival (OS), and adverse events (AE) were analyzed.
A total of 50 patients were identified; 41 (82%) were male. The median age at initiation of treatment with atezolizumab plus bevacizumab was 65 years, 41 (82%) patients had cirrhosis, 30 (73%) Child A, 9 (22%) B, and 2 (5%) C. A total of 34 patients (68%) received atezolizumab plus bevacizumab in the second-line setting and 16 (32%) in later lines. The best radiologic tumor responses were complete remission (2%), partial remission (30%), stable disease (36%), and progressive disease (18%), resulting in an objective response rate of 32% and a disease control rate of 68%. Median OS was 16.0 months (95% confidence interval 5.6-26.4 months), and median PFS was 7.1 months (95% confidence interval 4.4-9.8 months). AE grades 3-4 were observed in seven (14%) and resulted in death in three patients (6%). There were five (10%) bleeding events with a grade ≥ 3, including one (2%) with a fatal outcome.
Atezolizumab plus bevacizumab is effective in patients with aHCC who did not have access to this option as first-line therapy. The safety profile was consistent with previous reports.
Platelets are essential mediators of hemostasis to avoid excessive blood loss. Cirrhosis and chronic liver diseases are characterized by alterations in hemostasis. Alterations in the secondary ...hemostasis have been well studied, while defects in primary hemostasis, especially the consequences of cholestatic liver disease on platelet function are not well defined.
After bile duct ligation (BDL) platelet activation and thrombus formation were analyzed in mice.
BDL in mice had a moderate effect on platelet counts; however, intrinsic platelet activation was strongly reduced upon activation of the collagen receptor GPVI at early time points. 7 days after bile duct ligation, platelets displayed an almost complete loss of activation with reduced agonist-triggered release of alpha and dense granules and expression of integrin αIIbβ3 on the platelet surface. This activation defects resulted in strongly reduced thrombus formation under flow, reduced platelet adhesion to fibrinogen and bleeding complications in BDL mice as measured by tail bleeding experiments. Mechanistically, elevated nitric oxide and prostacyclin levels induced phosphorylation of Vasodilator-stimulated phosphoprotein (VASP), an established inhibitor of platelet activation. Furthermore increased tissue plasminogen activator in plasma of BDL mice led to enhanced plasmin levels that might be responsible for reduced glycoprotein expression of BDL platelets. Besides, high amounts of bile acids contribute to defective signal transduction as shown in platelets from mice fed with a cholic acid diet.
Cholestatic liver disease induces multiple platelet activation defects and impairs thrombus formation responsible for bleeding complications at least in mice.
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