Senescence and senotherapies in pediatric biliary cirrhosis

Premature senescence worsens the prognosis of adult chronic hepatobiliary diseases and some evidence suggests that this phenomenon also occurs in biliary atresia, which is the leading cause of pediatric liver transplantation. Since alternatives to liver transplantation are still lacking, the aim of our work was to investigate premature senescence in pediatric biliary cirrhosis and to assess senotherapies in vivo. We demonstrated that liver senescence is already present from early stage in biliary atresia and continues to progress until liver transplantation. Alagille syndrome livers displayed premature senescence as well. Human allogenic liver-derived progenitor cells decreased early senescence and improved liver disease in the bile duct ligation rat model of biliary cirrhosis. Although senotherapies are promising therapeutic tools to develop in pediatric biliary cirrhosis, such therapies will have to be further developed and improved before reaching clinical practice.(MED - Sciences médicales) -- UCL, 202

Les hépatopathies auto-immunes de l’enfant

Les hépatopathies auto-immunes de l’enfant incluent l’hépatite auto-immune (HAI) et la cholangiopathie auto-immune (CAI), qui consiste en l’association d’une HAI avec une atteinte des voies biliaires, souvent associéé à une maladie inflammatoire du tube digestif. L’HAI est particulièrement agressive chez l’enfant, et progresse rapidement en l’absence d’un traitement immunosuppresseur qui doit donc être instauré aussi précocement que possible. En cas de traitement adapté, 80% des patients présentent une rémission et une survie au long cours (1). La présente revue propose un aperçu des connaissances actuelles sur ces pathologies.[Autoimmune liver diseases of the child] The term autoimmune liver disorders in childhood refers to autoimmune hepatitis (AIH) and AIH/primary sclerosing cholangitis overlap syndrome, also termed autoimmune sclerosing cholangitis. In pedialric patients, AIH is a particularly aggressive disease that evolves rapidly, unless prompt immunosuppressant initiation. With appropriate treatment, 80% of patients achieve full remission and long-term survival [1]. This review is a state-of-the-art update on autoimmune liver disorders in childhood

An Optimized Protocol for Histochemical Detection of Senescence-associated Beta-galactosidase Activity in Cryopreserved Liver Tissue

Senescence-associated beta-galactosidase (SA-β-gal) activity assay is commonly used to evaluate the increased beta-galactosidase (β-gal) activity in senescent cells related to enhanced lysosomal activity. Although the optimal pH for β-gal is 4.0, this enzymatic activity has been most commonly investigated at a suboptimal pH by using histochemical reaction on fresh tissue material. In the current study, we optimized a SA-β-gal activity histochemistry protocol that can also be applied on cryopreserved hepatic tissue. This protocol was developed on livers obtained from control rats and after bile duct resection (BDR). A significant increase in β-gal liver activity was observed in BDR rats vs controls after 2 hr of staining at physiological pH 4.0 (6.98 ± 1.19% of stained/total area vs 0.38 ± 0.22; p<0.01) and after overnight staining at pH 5.8 (24.09 ± 6.88 vs 0.12 ± 0.08; p<0.01). Although we noticed that β-gal activity staining decreased with cryopreservation time (from 4 to 12 months of storage at -80C; p<0.05), the enhanced staining observed in BDR compared with controls remained detectable up to 12 months after cryopreservation (p<0.01). In conclusion, we provide an optimized protocol for SA-β-gal activity histochemical detection at physiological pH 4.0 on long-term cryopreserved liver tissue

Everolimus is Safe as a Second-/Third-Line Therapy in Pediatric Autoimmune Hepatitis

utoimmune hepatitis (AIH) can lead to progressive fibrosis in patients refractory to conventional therapy with prednisolone and azathioprine. The use of mammalian target of rapamycin (mTOR) inhibitors has recently emerged in refractory AIH, but no data have been published about everolimus in pediatric AIH to date. Our aim was to share our experience about everolimus as a second-/third-line therapy in pediatric AIH. Methods: Pretransplant AIH patients aged 0-18 years who received everolimus therapy from 2014 to 2021 were retrospectively identified. All patients underwent regular plasma monitoring of everolimus trough levels to avoid toxicity and assess adherence. Special attention was paid to the clinical and biochemical occurrence of everolimus-related adverse events. Results: We report six difficult-to-treat AIH patients who received everolimus therapy for 8-46 months (median 28 months). No side effects were reported when everolimus plasma trough levels were in the therapeutic range. Liver transaminases improved in 5 of 6 patients at everolimus introduction and significantly decreased at the last follow-up (FU) in our cohort (P < 0.05). None of our patients achieved complete biochemical remission at the last FU and 3 of 6 admitted to have suboptimal adherence to therapy. Conclusions: Our data bring preliminary safety for the use of everolimus as a second-/third-line therapy in pediatric AIH. Although liver transaminases improved in our cohort, prospective studies are needed to determine if everolimus can induce long-term remission

L’everolimus comme traitement de deuxième/troisième ligne dans l’hépatite auto-immune pédiatrique

Objectifs : L’hépatite auto-immune (HAI) est une maladie inflammatoire chronique qui peut mener à la cirrhose chez les patients réfractaires au traitement conventionnel. Les traitements de seconde ligne actuels ont une efficacité variable et un niveau de recommandation faible. Dans ce contexte, l’utilisation des inhibiteurs du mammalian target of rapamycin (mTOR) s’est récemment développée dans l’HAI réfractaire au traitement. L'everolimus a montré des résultats prometteurs dans une série limitée chez l'adulte, mais aucun rapport n’a été publié dans l’HAI pédiatrique à ce jour. L’objectif de notre travail était de partager notre expérience de l’everolimus comme thérapie de deuxième ou de troisième ligne dans l’HAI pédiatrique. Méthodes : Les patients âgés de 0 à 18 ans atteints d’HAI et non transplantés ayant reçu de l’everolimus entre 2014 et 2021 ont été identifiés rétrospectivement dans la base de données d’hépatologie pédiatrique des Cliniques Universitaires Saint-Luc (Bruxelles, Belgique). Tous les patients ont été soumis à un dosage régulier des taux plasmatiques d’everolimus afin d’éviter la toxicité et d’évaluer la compliance thérapeutique. Une attention particulière a été portée à la survenue d’effets secondaires cliniques et biochimiques attribuables à l’everolimus. Résultats : Six patients atteints d’HAI ont été traités par everolimus dans notre centre pour une durée comprise entre 8 et 48 mois (médiane 28 mois). Aucun effet secondaire n’a été rapporté lorsque les taux plasmatiques d’everolimus se situaient dans les normes thérapeutiques. Les transaminases hépatiques se sont améliorées chez 5/6 patients à l’instauration de l’everolimus et ont diminué significativement à la fin du suivi (p<0.05). Aucun patient n’est entré en rémission biochimique au sens strict au cours du suivi et 3/6 patients ont admis avoir une compliance suboptimale au traitement. Conclusions : Nos données préliminaires présentent l’everolimus comme une option thérapeutique de deuxième/troisième ligne sans risque en cas d’HAI réfractaire. Bien qu’une amélioration des transaminases hépatiques ait été observée dans notre cohorte, des études prospectives seront nécessaires afin de déterminer si l’everolimus peut induire une rémission clinique et biochimique au long cours

Vitamin K May Be A-OK, in Kids and Cholestatic Patients.

Comment on Routine Use of Vitamin K in the Treatment of Cirrhosis-Related Coagulopathy: Is it A-O-K? Maybe Not, We Say

Nasobiliary drainage prior to surgical biliary diversion in progressive familial intrahepatic cholestasis type II.

Progressive familial intrahepatic cholestasis (PFIC) can cause intense pruritus that is refractory to medical therapy. Surgical biliary diversion techniques, including partial internal biliary diversion (PIBD), have been developed over the years to relieve pruritus without requiring liver transplantation. No clinical or genetic features can currently predict postoperative pruritus response. We present three PFIC type 2 (PIFC 2) patients who underwent transient endoscopic nasobiliary drainage (NBD) prior to PIBD surgery. Two patients repeatedly responded to NBD and presented with complete pruritus resolution after subsequent PIBD. NBD failed technically in the third patient, and PIBD was partially successful. Mild post-endoscopic biological pancreatitis occurred in 2/6 NBD procedures and resolved spontaneously. The only adverse effect observed within 7 years post-PIBD was very mild transient osmotic diarrhea.Conclusion: Our limited data suggest that NBD is a safe and effective way to predict pruritus response before performing permanent biliary diversion surgery in PFIC patients.What is Known:• Surgical biliary diversion techniques have been developed to relieve intractable pruritus in progressive familial intrahepatic cholestasis (PFIC).• No clinical or genetic features can currently predict pruritus response to surgery.What is New: • Our data suggest that nasobiliary drainage could be a safe and effective tool to predict pruritus response to biliary diversion and avoid unnecessary surgery in PFIC patients

Alagille syndrome liver display premature senescence

Introduction: Alagille syndrome (ALGS) is an autosomal dominant disease characterized by a multisystem involvement including bile duct paucity and cholestasis, and caused by JAG1 or NOTCH2 mutations in most of the cases. Jagged1-Notch2 interactions are known to be crucial for intrahepatic biliary tract development, but the Notch signaling pathway is also involved in the juxtacrine transmission of senescence and in the induction and modulation of the senescence-associated secretory phenotype (SASP). Aim: Our aim was to investigate premature senescence in ALGS liver to better understand the involvement of Notch in senescence and SASP development. Methods: Liver tissue from ALGS patients was prospectively obtained at the time of liver transplantation (n=5) and compared to control livers (n=5). Results: We evidenced advanced premature senescence in the livers of five JAG1 mutated ALGS pediatric patients through increased senescence-associated beta-galactosidase activity (p<0.05), increased p16 and p21 gene expression (p<0.01), and increased p16 and γH2AX protein expression (p<0.01). Senescence was located in hepatocytes of the whole liver parenchyma as well as in remaining bile ducts. However, classical SASP markers (TGF-β1, IL-6, IL-8) were not overexpressed in the livers of our patients. Conclusions: We demonstrate for the first time that ALGS livers display important premature senescence despite Jagged1 mutation, but we could not evidence any increase of SASP markers in our cohort, possibly due to a disrupted SASP induction caused by abnormal Notch signaling

Premature senescence of the liver in Alagille patients

Introduction Alagille syndrome (ALGS) is an autosomal dominant disease characterized by a multisystem involvement including bile duct paucity and cholestasis, caused by JAG1 or NOTCH2 mutations in most of the cases. Jagged1-Notch2 interactions are known to be crucial for intrahepatic biliary tract development, but the Notch signaling pathway is also involved in the juxtacrine transmission of senescence and in the induction and modulation of the senescence-associated secretory phenotype (SASP). Aim Our aim was to investigate premature senescence and SASP in ALGS livers. Methods Liver tissue from ALGS patients was prospectively obtained at the time of liver transplantation (n = 5) and compared to control livers (n = 5). Results We evidenced advanced premature senescence in the livers of five JAG1 mutated ALGS pediatric patients through increased senescence-associated beta-galactosidase activity (pConclusions We demonstrate for the first time that ALGS livers display important premature senescence despite Jagged1 mutation, underlying the complexity of senescence and SASP development pathways

Liver-derived signaling cells improve senescence and modulate ductular reaction in biliary cirrhosis

Objectives: Premature senescence has been extensively characterized in adult chronic hepatobiliary diseases and worsens liver function and fibrosis evolution, generating a need for senolytic therapies that can be translated to clinical applications. Mesenchymal stem cells (MSCs), also referred as medicinal signaling cells, repeatedly demonstrated to improve liver function and histology in chronic liver disease and even reduced cardiac and skin senescence in aging rats. However, the effect of MSCs on liver senescence has never been investigated. Our aim was to study the effect of human adult liver-derived progenitor cells (HALPC), a suspension of liver-derived signaling cells obtained from healthy adult human liver, on liver senescence in a preclinical model of juvenile biliary cirrhosis. Methods: Bile duct ligation (BDL) was performed on 2-months old male Wistar rats and controls underwent sham procedure. Liver senescence was extensively characterized in the BDL model through senescence-associated beta-galactosidase (SA-β-gal) activity, p21 and p16 protein/gene expression, multiple immunofluorescence staining (p21, CK19, HNF4α) and gene expression of senescence-associated secretory phenotype (SASP) markers. HALPC were then transplanted through the penile vein of BDL rats 48 hours after the surgery at two doses (12.5 x 106 cells/kg versus 1.25 x 106 cells/kg, n=6 for each group) and compared to the vehicle (n=6). All animals were sacrificed 72 hours after the injection. Results: Our results show the progressive development of senescence in BDL livers, the earliest marker of senescence being p21, already detectable 48 hours after the surgery (p<0.05). Senescence first developed in cholangiocytes and subsequently extended to hepatocytes in the parenchyma. Gene expression of SASP markers IL6, IL1β and TGFβ1 increased in diseased livers (p<0.05). The progression of senescence strongly correlated with fibrosis and ductular reaction (DR) development in our model of biliary cirrhosis (r=0.96 and 0.97 respectively; p<0.0001). HALPC injections (high and low doses) decreased senescence in BDL rats (p21 gene expression) (p<0.05). The high dose injection also improved biliary injury (serum γGT) and DR (Sox9 gene expression) as compared to low dose and vehicle subgroups (p<0.05). Conclusions: Our data position BDL as a robust model of senescence and provide evidence that HALPC can decrease liver senescence and modulate DR in biliary cirrhosis. Those results place liver-derived signaling cells as a potential senolytic tool to develop in chronic hepatobiliary diseases in order to limit the worsening of the disease related to senescence progression