Tumor necrosis factor-alpha and interleukin-6 reduce bile canalicular contractions of rat hepatocytes

ICAM-1 nanoclusters regulate hepatic epithelial cell polarity by leukocyte adhesion-independent control of apical actomyosin

Epithelial intercellular adhesion molecule (ICAM)-1 is apically polarized, interacts with, and guides leukocytes across epithelial barriers. Polarized hepatic epithelia organize their apical membrane domain into bile canaliculi and ducts, which are not accessible to circulating immune cells but that nevertheless confine most of ICAM-1. Here, by analyzing ICAM-1_KO human hepatic cells, liver organoids from ICAM-1_KO mice and rescue-of-function experiments, we show that ICAM-1 regulates epithelial apicobasal polarity in a leukocyte adhesion-independent manner. ICAM-1 signals to an actomyosin network at the base of canalicular microvilli, thereby controlling the dynamics and size of bile canalicular-like structures. We identified the scaffolding protein EBP50/NHERF1/SLC9A3R1, which connects membrane proteins with the underlying actin cytoskeleton, in the proximity interactome of ICAM-1. EBP50 and ICAM-1 form nano-scale domains that overlap in microvilli, from which ICAM-1 regulates EBP50 nano-organization. Indeed, EBP50 expression is required for ICAM-1-mediated control of BC morphogenesis and actomyosin. Our findings indicate that ICAM-1 regulates the dynamics of epithelial apical membrane domains beyond its role as a heterotypic cell-cell adhesion molecule and reveal potential therapeutic strategies for preserving epithelial architecture during inflammatory stress.

Atazanavir-induced unconjugated hyperbilirubinemia prevents vascular hyporeactivity during experimental human endotoxemia

Objective

Inflammation-induced free radical release is important in the pathogenesis of several diseases, including atherosclerosis and sepsis. Heme oxygenase (HO) breaks down heme into carbon monoxide, iron, and biliverdin. Biliverdin IXα is directly converted to bilirubin by biliverdin reductase. Unconjugated bilirubin is a powerful antioxidant, and elevated levels have beneficial effects in preclinical models and human cardiovascular disease. However, its impact during acute inflammation in humans is unknown. In the present study, we investigated the impact of atazanavir-induced (unconjugated) hyperbilirubinemia on antioxidant capacity, inflammation, and vascular dysfunction in human experimental endotoxemia.

Approach and results

Following double-blinded four-day treatment with atazanavir 2dd300 mg (or placebo), twenty healthy male volunteers received 2 ng/kg Escherichia coli lipopolysaccharide intravenously. Blood was drawn to determine the bilirubin levels, antioxidant capacity, and cytokine response. It was demonstrated that following atazanavir treatment, total bilirubin concentrations increased to maximum values of 4.67 (95%CI 3.91-5.59) compared to 0.82 (95%CI 0.64-1.07) mg/dL in the control group (p<0.01). Furthermore, the anti-oxidant capacity, as measured by the ferric-reducing ability of plasma (FRAP), was significantly increased with 36% in hyperbilirubinemia subjects (p<0.0001), and FRAP concentrations correlated strongly to bilirubin concentrations (R2 = 0.77, p<0.001). Hyperbilirubinemia attenuated the release of interleukin-10 from 377 (95%CI 233-609) to 219 (95%CI 152-318) pg/mL (p=0.01), whereas the release of pro-inflammatory cytokines remained unaltered. In vitro, in the absence of hyperbilirubinemia, atazanavir did not influence lipopolysaccharide-induced cytokine release in a whole blood assay. Vascular function was assessed using forearm venous occlusion plethysmography after intra-arterial infusion of acetylcholine and nitroglycerin. Hyperbilirubinemia completely prevented the LPS-associated blunted vascular response to acetylcholine and nitroglycerin.

Conclusions

Atazanavir-induced hyperbilirubinemia increases antioxidant capacity, attenuates interleukin-10 release, and prevents vascular hyporesponsiveness during human systemic inflammation elicited by experimental endotoxemia.

Clinical trial registration

http://clinicaltrials.gov, identifier NCT00916448.

Non-amyloid liver involvement in familial Mediterranean fever: A systematic literature review

INTRODUCTION

Familial Mediterranean fever (FMF), the most frequent autoinflammatory disease, is caused by mutations in the MEFV gene. It is characterized by recurrent febrile attacks of polyserositis. Liver abnormalities may develop during its course, but they remain poorly defined.

OBJECTIVE

To describe liver involvement in FMF patients.

METHODS

A systematic search was conducted through PubMed/Medline and Embase from 1946 to January 2020. All articles describing children and adults with FMF and liver involvement were included. Patients with amyloidosis were excluded. The selected full-text articles were independently reviewed by three investigators.

RESULTS

Forty-three articles were identified, of which 20 articles with a total of 99 patients were included: 74 adults, 23 children and two patients of unknown age. Ten patients had cryptogenic cirrhosis, 48 had nonalcoholic fatty liver disease (NAFLD), four had Budd-Chiari syndrome (BCS), 12 had isolated hyperbilirubinaemia and 25 had elevated liver enzymes.

CONCLUSION

Despite a low prevalence of metabolic risk factors, FMF may be associated with NAFLD and cryptogenic cirrhosis as a consequence of chronic or recurrent inflammation. FMF patients should be regularly screened for liver injury. The latter may be prevented and treated by daily colchicine intake. The evidence was insufficient to establish an association with BCS, hyperbilirubinaemia or autoimmune hepatitis.

Severe liver involvement in two patients with long-term history of fever: remember familial Mediterranean fever

Familial Mediterranean fever (FMF) is characterised by recurrent, self-limited fever attacks and serositis. Severe liver involvement has rarely been reported. We present two FMF cases of a 55-year-old man and a 20-year-old woman in whom the prevailing manifestations were recurrent unexplained episodes of anicteric hepatitis (man) and recurrent severe jaundice (woman). A long-term history of recurrent self-limited episodes of fever was also claimed in both. After exclusion of infectious, malignant, autoimmune, and liver and biliary diseases, a diagnosis of FMF as confirmed by molecular analysis was established. The patients started colchicine 1 mg/day with immediate resolution of symptoms. During follow-up, no new episodes of fever and exacerbation of liver biochemical parameters have been recorded for 5 and 1 years. Physicians must keep FMF in mind in patients with recurrent episodes of unexplained severe liver impairment and fever and especially in regions like Mediterranean basin where hereditary periodic fever syndromes are common.

TGF-β-SMAD3 signaling mediates hepatic bile acid and phospholipid metabolism following lithocholic acid-induced liver injury

Transforming growth factor-β (TGFβ) is activated as a result of liver injury, such as cholestasis. However, its influence on endogenous metabolism is not known. This study demonstrated that TGFβ regulates hepatic phospholipid and bile acid homeostasis through MAD homolog 3 (SMAD3) activation as revealed by lithocholic acid-induced experimental intrahepatic cholestasis. Lithocholic acid (LCA) induced expression of TGFB1 and the receptors TGFBR1 and TGFBR2 in the liver. In addition, immunohistochemistry revealed higher TGFβ expression around the portal vein after LCA exposure and diminished SMAD3 phosphorylation in hepatocytes from Smad3-null mice. Serum metabolomics indicated increased bile acids and decreased lysophosphatidylcholine (LPC) after LCA exposure. Interestingly, in Smad3-null mice, the metabolic alteration was attenuated. LCA-induced lysophosphatidylcholine acyltransferase 4 (LPCAT4) and organic solute transporter β (OSTβ) expression were markedly decreased in Smad3-null mice, whereas TGFβ induced LPCAT4 and OSTβ expression in primary mouse hepatocytes. In addition, introduction of SMAD3 enhanced the TGFβ-induced LPCAT4 and OSTβ expression in the human hepatocellular carcinoma cell line HepG2. In conclusion, considering that Smad3-null mice showed attenuated serum ALP activity, a diagnostic indicator of cholangiocyte injury, these results strongly support the view that TGFβ-SMAD3 signaling mediates an alteration in phospholipid and bile acid metabolism following hepatic inflammation with the biliary injury.

Liver involvement in children with Familial Mediterranean fever

AIM

Familial Mediterranean fever is characterised by recurrent, febrile, inflammatory attacks of the serosal membranes. Prolonged inflammatory response is triggered secondary to cytokine stimulation due to reduced activity of pyrin. Inflammatory cytokines play major role in the pathogenesis of acute liver injury; and chronic, recurrent cytokine production may cause chronic hepatitis/cirrhosis. We aimed to analyse liver involvement in children with Familial Mediterranean fever.

PATIENTS

The study included 58 patients with Familial Mediterranean fever. Patients with liver involvement were examined in detail.

RESULTS

Liver involvement was seen in 11 of 58 patients (18.9%). Two patients (3.4%) had abnormal liver enzymes during the diagnostic evaluation, whilst 9 patients (15.5%) were admitted with the features of liver diseases, and had final diagnosis of Familial Mediterranean fever (2 had Budd-Chiari syndrome, 5 had chronic hepatitis/cirrhosis, 2 had acute hepatitis). None of the demographic factors or laboratory findings was different between the patients with or without liver involvement M694V allele was more common in patients with liver involvement but did not reach significant difference (50% vs. 33.6%, p=0.21). All the patients showed clinical and laboratory improvement after colchicine.

CONCLUSION

Paediatric hepatologists must keep Familial Mediterranean fever in mind in the patients with cryptogenic hepatitis/cirrhosis especially in regions where hereditary inflammatory diseases are common.

Changes in the liver function tests during the attacks of familial Mediterranean fever

The present study aims to investigate whether or not FMF patients display abnormal liver functions during attack periods. About 41 consecutive FMF patients with attacks were enrolled on this study. Bilirubin levels, liver transaminases, erythrocyte sedimentation rate and C-reactive protein (C-RP) levels were determined within the first 72 h after the onset of attacks. This procedure could be performed on only 28 of these 41 FMF patients, 4 weeks after the attack of the patients' had completely disappeared. As for the disease control group, 44 patients were determined to be eligible for the study. Another 31 healthy individuals were also included. Hyperbilirubinemia was determined in 11 of the 41 patients (26.8%) with FMF. The number of FMF patients with hyperbilirubinemia was significantly higher than in DC and HC (P < 0.001, P = 0.03, respectively). Levels of liver transaminases slightly increased in four patients with FMF during the attack and two of these four patients had also mild hyperbilirubinemia. A significant correlation was found between C-RP levels and total and unconjugated bilirubin levels in FMF patients with attack (r = 0.43, P = 0.01; r = 0.40, P = 0.02, respectively). In conclusion, mild hyperbilirubinemia may occur in one-fourth of the patients with FMF during the attack period.

Sepsis and cholestasis

Sepsis-associated cholestasis should always be considered as part of the differential diagnosis of jaundice in the hospitalized or critically ill patient. The development of a disproportionate elevation of serum bilirubin in comparison with serum alkaline phosphatase and serum aminotransferases should be considered an early warning sign of an underlying infection, even in the absence of fever,leukocytosis, or other signs or symptoms. Prompt recognition and appropriate medical and surgical intervention may reduce morbidity and mortality.