ABSTRACT
BACKGROUND: With the implementation of the 11th edition of the International Classification of Diseases (ICD-11) and the publication of the metabolic dysfunction-associated fatty liver disease (MAFLD) nomenclature in 2020, it is important to establish consensus for the coding of MAFLD in ICD-11. This will inform subsequent revisions of ICD-11. METHODS: Using the Qualtrics XM and WJX platforms, questionnaires were sent online to MAFLD-ICD-11 coding collaborators, authors of papers, and relevant association members. RESULTS: A total of 890 international experts in various fields from 61 countries responded to the survey. We also achieved full coverage of provincial-level administrative regions in China. 77.1% of respondents agreed that MAFLD should be represented in ICD-11 by updating NAFLD, with no significant regional differences (77.3% in Asia and 76.6% in non-Asia, p = 0.819). Over 80% of respondents agreed or somewhat agreed with the need to assign specific codes for progressive stages of MAFLD (i.e. steatohepatitis) (92.2%), MAFLD combined with comorbidities (84.1%), or MAFLD subtypes (i.e., lean, overweight/obese, and diabetic) (86.1%). CONCLUSIONS: This global survey by a collaborative panel of clinical, coding, health management and policy experts, indicates agreement that MAFLD should be coded in ICD-11. The data serves as a foundation for corresponding adjustments in the ICD-11 revision.
Subject(s)
International Classification of Diseases , Non-alcoholic Fatty Liver Disease , Humans , Non-alcoholic Fatty Liver Disease/epidemiology , Non-alcoholic Fatty Liver Disease/classification , Surveys and Questionnaires , Global HealthABSTRACT
Liver cancer is globally the third leading cause of death from cancer. Hepatocellular carcinoma (HCC) develops in patients with underlying liver disease. The fraction of HCC attributed to nonalcoholic fatty liver disease (NAFLD) shows an accelerated increase in the last decades, being already responsible for 15% of all HCC cases. Similar to other causes of liver cirrhosis, patients with NAFLD-associated cirrhosis should be enrolled in HCC-screening programs, yet these patients are under-screened, and currently are less than half likely to be proposed for HCC screening as compared to patients with HCV-associated cirrhosis. NAFLD-associated HCC has the peculiarity of occurring in precirrhotic phases in 20-50% of the cases. Currently, HCC screening in precirrhotic NAFLD patients is not routinely recommended, since the risk of developing HCC is very low. However, because NAFLD affects one-third of the worldwide population, noncirrhotic NAFLD already accounts for 6% of HCC cases. As such, it is pressing to develop stratification tools, in order to personalize the individual risk of HCC development in a patient with NAFLD, allowing precision HCC-screening programs. This review summarizes the epidemiology of NAFLD-associated HCC with a critical analysis of current HCC-screening recommendations.
O cancro do fígado é, globalmente, a terceira causa de morte por cancro. O carcinoma hepatocelular (CHC) desenvolve-se em doentes com doença hepática crónica subjacente. A fracção de CHC atribuível ao fígado gordo não alcoólico (FGNA) tem vindo a aumentar com uma aceleração no seu crescimento nas últimas décadas, sendo atualmente responsável por 15% dos casos de CHC. À semelhança do que ocorre com outras causas de cirrose hepática, os doentes com cirrose associada a FGNA devem ser inseridos em programas de rastreio de CHC. Contudo, esses doentes são sub-rastreados, já que a probabilidade de serem incluídos em programas de rastreio de CHC é menos de metade comparando com doentes com cirrose associada a hepatite C crónica. O CHC associado ao FGNA tem a particularidade de ocorrer em fases pré-cirróticas em 20 a 50% dos casos. O rastreio de CHC em doentes com FGNA em fase pré-cirrótica não está recomendado por rotina, uma vez que, ainda assim, o risco destes doentes desenvolverem CHC é muito baixo. No entanto, uma vez que um terço da população mundial tem FGNA, o FGNA em não cirróticos corresponde a 6% de todos os casos de CHC. Assim sendo, é urgente o desenvolvimento de métodos de estratificação, por forma a personalizar o risco individual de desenvolvimento de CHC em doentes com FGNA, permitindo maior precisão nos programas de rastreio de CHC. Esta revisão sumariza a epidemiologia de CHC associado ao FGNA, com uma análise crítica das atuais recomendações de rastreio de CHC.
ABSTRACT
MASLD prevalence is growing towards the leading cause of end-stage liver disease. Up to today, the most effective treatment is weight loss. Weight loss interventions are moving from lifestyle changes to bariatric surgery or endoscopy, and, more recently, to a new wave of anti-obesity drugs that can compete with bariatric surgery. Liver-targeted therapy is a necessity for those patients who already present liver fibrosis. The field is moving fast, and in the near future, we will testify to a disruptive change in MASLD treatment, similar to the paradigm-shift that occurred for hepatitis C almost one decade ago with direct antiviral agents.
Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Non-alcoholic Fatty Liver Disease , Humans , Non-alcoholic Fatty Liver Disease/diagnosis , Non-alcoholic Fatty Liver Disease/epidemiology , Non-alcoholic Fatty Liver Disease/pathology , Carcinoma, Hepatocellular/diagnosis , Carcinoma, Hepatocellular/epidemiology , Carcinoma, Hepatocellular/pathology , Liver Neoplasms/diagnosis , Liver Neoplasms/epidemiology , Liver Neoplasms/pathology , Risk Factors , Liver Cirrhosis/pathologyABSTRACT
Celiac disease (CD) is a common autoimmune disease affecting around 1% of the population. It consists of an immune-mediated enteropathy, triggered by gluten exposure in susceptible patients. All patients with CD, irrespective of the presence of symptoms, must endure a lifelong gluten-free diet (GFD). This is not an easy task due to a lack of awareness of the gluten content in foods and the extensive incorporation of gluten in processed foods. Furthermore, a GFD imposes a sense of limitation and might be associated with decreased quality of life in CD patients. This results in gluten contamination in the diet of four out of five celiac patients adhering to a GFD. Furthermore, one in three adult patients will report persistent symptoms and two in three will not achieve full histological recovery when on a GFD. In recent years, there has been extensive research conducted in the quest to find the holy grail of pharmacological treatment for CD. This review will present a concise description of the current rationale and main clinical trials related to CD drug therapy.
Subject(s)
Celiac Disease , Adult , Humans , Celiac Disease/diagnosis , Quality of Life , Glutens , Diet, Gluten-Free , FoodABSTRACT
A 42-year-old man with no relevant past medical history presented with intermittent mild icterus and no signs of chronic liver disease. Laboratory tests were notable for hyperbilirubinemia (total 7.97 mg/dL, direct 5.37 mg/dL), bilirubinuria, no signs of hemolysis, normal liver tests and lipids profile. Abdominal ultrasound was unremarkable. A panel of chronic liver diseases was negative except for increased serum (147.4 µg/dL) and urinary (179 µg/24 h) copper, with normal ceruloplasmin. No other Leipzig criteria for Wilson's disease were found, including a negative test for ATP7B gene mutations (by exome sequencing). Total urinary coproporphyrin was normal with predominance of isomer I (86% of total urinary coproporphyrin output). Clinical and laboratorial profile was compatible with Dubin-Johnson syndrome; however, exome sequencing and search for deletions in the ABBC2 gene (encoding MRP2) only found a heterozygous potentially pathogenic variant (c.1483A>G - p.Lys495Glu). Additional extended molecular analysis of genes implicated in bilirubin metabolism found a homozygous deletion of a region encompassing exons 4-16 of SLCO1B3 gene (encoding OATP1B3) and all SLCO1B1 exons (encoding OATP1B1), thereby establishing Rotor syndrome diagnosis. Rotor and Dubin-Johnson syndromes are rare autosomal recessive liver diseases characterized by chronic conjugated hyperbilirubinemia, caused by the absence of the hepatic function OATP1B1/B3 (leading to impaired hepatic bilirubin reuptake and storage) and MRP2 transporters (leading to impaired hepatic bilirubin excretion), respectively. We report a case of compound hereditary hyperbilirubinemia with a misleading presentation with special focus on its diagnosis, particularly the advantage of extensive unbiased genetic testing by dedicated laboratories. With this case, we aim to highlight the necessity of establishing a diagnosis, reassuring the patient, and avoiding unnecessary invasive and costly diagnostic procedures.
ABSTRACT
Bilirubin, a breakdown product of heme, is normally glucuronidated and excreted by the liver into bile. Failure of this system can lead to a buildup of conjugated bilirubin in the blood, resulting in jaundice. Hyperbilirubinemia is an important clinical sign that needs to be investigated under a stepwise evaluation. Inherited non-hemolytic conjugated hyperbilirubinemic conditions include Dubin-Johnson syndrome (caused by mutations affecting ABCC2 gene) and Rotor syndrome (caused by the simultaneous presence of mutations in SLCO1B1 and SLCO1B3 genes). Although classically viewed as benign conditions requiring no treatment, they lately gained an increased interest since recent studies suggested that mutations in the responsible genes leading to hyperbilirubinemia, as well as minor genetic variants, may result in an increased susceptibility to drug toxicity. This article provides a comprehensive review on the pathophysiology of Dubin-Johnson and Rotor syndromes, presenting the current knowledge concerning the molecular details and basis of these conditions.
Subject(s)
Hyperbilirubinemia, Hereditary , Jaundice, Chronic Idiopathic , Bilirubin , Heme/metabolism , Humans , Hyperbilirubinemia/etiology , Hyperbilirubinemia/genetics , Hyperbilirubinemia, Hereditary/diagnosis , Hyperbilirubinemia, Hereditary/genetics , Jaundice, Chronic Idiopathic/diagnosis , Jaundice, Chronic Idiopathic/genetics , Liver-Specific Organic Anion Transporter 1/geneticsABSTRACT
Sedentarism is the pandemic of modern times. It is associated with several medical conditions including obesity, type 2 diabetes mellitus, cardiovascular diseases and also liver disease, particularly metabolic dysfunction associated fatty liver disease (MAFLD). In an era when MAFLD is the most prevalent chronic liver disease worldwide, whilst no pharmacological therapy has been approved for it, exercise has proved to be effective in improving liver steatosis. Interestingly, exercise decreases liver fat even in the absence of weight loss. The challenge for the clinician is to motivate the obese patient with MAFLD, and associated co-morbidities, who has crystallized a sedentary behavior, at times when every need is at the distance of a click on the Internet, and the entire world can be visited behind a screen. In this review, the aggregate evidence on the mechanisms and effects of exercise in the management of MAFLD is summarized, with simple recommendations for everyday clinical practice.
ABSTRACT
BACKGROUND: Most long-term heavy drinkers do not have clinically evident chronic liver disease (CLD). However, at any time-point, their risk of developing CLD remains unknown. We aimed to evaluate the long-term outcomes of a group of heavy drinkers, without evidence of CLD at baseline. METHODS: A cohort of 123 long-term heavy drinkers without CLD were prospectively recruited in 2002 and retrospectively followed until 2018. RESULTS: At baseline (2002), median alcohol consumption was 271±203g/day during 21.5±20 years, 65% being abstinent during the previous 1.75±5 months. Patients were followed for 14±3 years. During follow-up, 53% reported any alcohol intake. Alcohol consumption during follow-up associated weakly with either 1- or 6-months previous abstinence at baseline. Until 2018, progression to CLD occurred in 6%, associating with years of alcohol intake during follow-up (OR 1.15 [1.01-1.31]) and baseline alkaline-phosphatase (OR 1.05 [1.01-1.10]). During follow-up, being abstinent for at least 1 year positively associated with CLD-free survival. 27% died (55% of cancer-mostly oropharyngeal cancer, 27% of cardiovascular disease, and 9% of liver disease), with a mean age of 71 years [69-74] (10 years less than the expected in the Portuguese population). Achieving abstinence for at least 1 year positively associated with overall survival, while smoking, and hepatic steatosis at baseline associated negatively. CONCLUSION: Long-term heavy drinkers seemed to have a decreased life expectancy compared with the overall Portuguese population. Cancer was the main cause of death. Our results suggest that progression to CLD depends mostly on continued alcohol intake. Alcohol abstinence, even if temporary, seems to decrease the risks of CLD and mortality.
Subject(s)
Alcohol Drinking/physiopathology , Liver Diseases/mortality , Neoplasms/mortality , Alkaline Phosphatase/metabolism , Cardiovascular Diseases/metabolism , Humans , Liver Diseases/epidemiology , Neoplasms/epidemiology , Prospective Studies , Risk FactorsABSTRACT
INTRODUCTION: Frailty and sarcopenia associate with increased mortality in patients with liver cirrhosis on the transplant waitlist. We conducted a systematic review on the impact of pretransplant frailty and sarcopenia on post-transplant outcomes in adult patients with liver cirrhosis. METHODS: We performed a search in Medline, Embase and Cochrane Central. Of the 12276 references initially recovered, 34 were included. RESULTS: Frailty and sarcopenia presented a negative impact on post-transplant outcomes and seemed to associate with an overall two-fold reduction in early and 50% reduction in late survival, for severe conditions, according to the largest cohorts. These patients required longer ICU and hospitalization time, had higher rates of sepsis and respiratory complications and lower graft-survival. The reversibility of frailty depended on the severity of functional impairment and on the co-morbidities contributing to frailty. Reversibility of sarcopenia occurred in only a minority of patients, in unbiased studies. CONCLUSION: Frailty and sarcopenia are double-edged swords: patients with frailty/sarcopenia should be prioritized for liver transplantation due to increased mortality on the waitlist; however, severe frailty/sarcopenia may justify delisting because it associates with dismal prognosis post-liver transplantation. Patients presenting mild to moderate frailty/sarcopenia, should be submitted to liver transplantation before those conditions worsen to a level that significantly impacts post-liver transplantation outcomes.
Subject(s)
Frailty , Liver Transplantation , Sarcopenia , Adult , Frailty/complications , Frailty/diagnosis , Humans , Liver Cirrhosis/complications , Liver Cirrhosis/diagnosis , Liver Cirrhosis/surgery , Liver Transplantation/adverse effects , Prognosis , Sarcopenia/etiologySubject(s)
Burns, Chemical/pathology , Esophagus/pathology , Gastric Fundus/pathology , Potassium Permanganate/adverse effects , Accidents, Home , Capsules , Esophagoscopy , Esophagus/injuries , Female , Gastric Fundus/injuries , Gastroscopy , Humans , Middle Aged , Potassium Permanganate/administration & dosageABSTRACT
INTRODUCTION: Nonalcoholic fatty liver disease (NAFLD) encompasses simple steatosis and steatohepatitis (NASH) with or without fibrosis/cirrhosis and hepatocellular carcinoma. NAFLD occurs epidemically in most areas of the world, contributes to cardiovascular events and liver-related mortality and therefore exacts a major economic toll. Areas covered: Here we summarize what clinicians should know about NAFLD histopathology in adults. We report on the individual histological features and scoring systems of NAFLD: the NAFLD activity score (NAS) introduced by the NASH-Clinical Research Network, the 'Fatty Liver Inhibition of Progression' algorithm and Steatosis, Activity, and Fibrosis (SAF) score. Pros and cons of histological classifications in NASH are discussed. Special emphasis is given to liver histopathology in some high-risk patient groups, such as those with severe obesity and type 2 diabetes. Moreover, we also examine the relationship between liver histopathology and clinical features, and the impact of liver histopathology on the long-term prognosis of NAFLD. Finally, we propose an integrated diagnostic approach which utilizes both non-invasive tools and liver biopsy in those individual patients with suspected NAFLD. Expert commentary: Based on expert opinions, we conclude with a research agenda on NAFLD which focuses on the most burning topics to be addressed over the next five years.
Subject(s)
Carcinoma, Hepatocellular/pathology , Liver Cirrhosis/pathology , Liver Neoplasms/pathology , Liver/pathology , Non-alcoholic Fatty Liver Disease/pathology , Biopsy , Carcinoma, Hepatocellular/diagnostic imaging , Carcinoma, Hepatocellular/epidemiology , Humans , Liver Cirrhosis/diagnostic imaging , Liver Cirrhosis/epidemiology , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/epidemiology , Non-alcoholic Fatty Liver Disease/classification , Non-alcoholic Fatty Liver Disease/diagnostic imaging , Non-alcoholic Fatty Liver Disease/epidemiology , Predictive Value of Tests , Prognosis , Risk Factors , Severity of Illness IndexABSTRACT
Liver disease remains a leading cause of mortality worldwide despite recent successes in the field of viral hepatitis, because increases in alcohol consumption and obesity are fuelling an epidemic of chronic fatty liver disease for which there are currently no effective medical therapies. About 20% of individuals with chronic liver injury ultimately develop end-stage liver disease due to cirrhosis. Hence, treatments to prevent and reverse cirrhosis in individuals with ongoing liver injury are desperately needed. The development of successful treatments requires an improved understanding of the mechanisms controlling liver disease progression. The liver responds to diverse insults with a conserved wound healing response, suggesting that it might be generally beneficial to optimise pathways that are crucial for effective liver repair. The Hedgehog pathway has emerged as a potential target based on compelling preclinical and clinical data, which demonstrate that it critically regulates the liver's response to injury. Herein, we will summarise evidence of the Hedgehog pathway's role in liver disease and discuss how modulating pathway activity might be applied to improve liver disease outcomes.
Subject(s)
Hedgehog Proteins/physiology , Liver Diseases , Signal Transduction , Disease Management , Humans , Liver Diseases/metabolism , Liver Diseases/therapy , PrognosisABSTRACT
BACKGROUND: Obesity is associated with multiple diseases, but it is unclear how obesity promotes progressive tissue damage. Recovery from injury requires repair, an energy-expensive process that is coupled to energy availability at the cellular level. The satiety factor, leptin, is a key component of the sensor that matches cellular energy utilization to available energy supplies. Leptin deficiency signals energy depletion, whereas activating the Hedgehog pathway drives energy-consuming activities. Tissue repair is impaired in mice that are obese due to genetic leptin deficiency. Tissue repair is also blocked and obesity enhanced by inhibiting Hedgehog activity. We evaluated the hypothesis that loss of leptin silences Hedgehog signaling in pericytes, multipotent leptin-target cells that regulate a variety of responses that are often defective in obesity, including tissue repair and adipocyte differentiation. RESULTS: We found that pericytes from liver and white adipose tissue require leptin to maintain expression of the Hedgehog co-receptor, Smoothened, which controls the activities of Hedgehog-regulated Gli transcription factors that orchestrate gene expression programs that dictate pericyte fate. Smoothened suppression prevents liver pericytes from being reprogrammed into myofibroblasts, but stimulates adipose-derived pericytes to become white adipocytes. Progressive Hedgehog pathway decay promotes senescence in leptin-deficient liver pericytes, which, in turn, generate paracrine signals that cause neighboring hepatocytes to become fatty and less proliferative, enhancing vulnerability to liver damage. CONCLUSIONS: Leptin-responsive pericytes evaluate energy availability to inform tissue construction by modulating Hedgehog pathway activity and thus, are at the root of progressive obesity-related tissue pathology. Leptin deficiency inhibits Hedgehog signaling in pericytes to trigger a pericytopathy that promotes both adiposity and obesity-related tissue damage.
Subject(s)
Hepatic Stellate Cells/physiology , Leptin/genetics , Obesity/physiopathology , Smoothened Receptor/genetics , Smoothened Receptor/metabolism , Adipocytes/cytology , Adipocytes/metabolism , Adipose Tissue/cytology , Animals , Cell Differentiation , Cell Movement , Cell Proliferation , Cells, Cultured , Hedgehog Proteins/physiology , Hepatic Stellate Cells/cytology , Hepatic Stellate Cells/metabolism , Leptin/deficiency , Leptin/metabolism , Mesenchymal Stem Cells/cytology , Mesenchymal Stem Cells/metabolism , Mesenchymal Stem Cells/physiology , Mice , Mice, Obese , Myofibroblasts/cytology , Myofibroblasts/metabolism , Obesity/genetics , Paracrine Communication/genetics , Receptors, Leptin/metabolism , Smoothened Receptor/agonistsABSTRACT
Recently, the importance of the gut-liver-adipose tissue axis has become evident. Nonalcoholic fatty liver disease (NAFLD) is the hepatic disease of a systemic metabolic disorder that radiates from energy-surplus induced adiposopathy. The gut microbiota has tremendous influences in our whole-body metabolism, and is crucial for our well-being and health. Microorganisms precede humans in more than 400 million years and our guest flora evolved with us in order to help us face aggressor microorganisms, to help us maximize the energy that can be extracted from nutrients, and to produce essential nutrients/vitamins that we are not equipped to produce. However, our gut microbiota can be disturbed, dysbiota, and become itself a source of stress and injury. Dysbiota may adversely impact metabolism and immune responses favoring obesity and obesity-related disorders such as insulin resistance/diabetes mellitus and NAFLD. In this review, we will summarize the latest evidence of the role of microbiota/dysbiota in diet-induced obesity and NAFLD, as well as the potential therapeutic role of targeting the microbiota in this set.
Subject(s)
Diet , Microbiota , Non-alcoholic Fatty Liver Disease/microbiology , Obesity/microbiology , Animals , Humans , Intestines/microbiology , Non-alcoholic Fatty Liver Disease/drug therapy , Non-alcoholic Fatty Liver Disease/pathology , Obesity/pathology , Probiotics/administration & dosageABSTRACT
Nonalcoholic steatohepatitis (NASH) is a necro-inflammatory response that ensues when hepatocytes are injured by lipids (lipotoxicity). NASH is a potential outcome of nonalcoholic fatty liver (NAFL), a condition that occurs when lipids accumulate in hepatocytes. NASH may be reversible, but it can also result in cirrhosis and primary liver cancer. We are beginning to learn about the mechanisms of progression of NAFL and NASH. NAFL does not inevitably lead to NASH because NAFL is a heterogeneous condition. This heterogeneity exists because different types of lipids with different cytotoxic potential accumulate in the NAFL, and individuals with NAFL differ in their ability to defend against lipotoxicity. There are no tests that reliably predict which patients with NAFL will develop lipotoxicity. However, NASH encompasses the spectrum of wound-healing responses induced by lipotoxic hepatocytes. Differences in these wound-healing responses among individuals determine whether lipotoxic livers regenerate, leading to stabilization or resolution of NASH, or develop progressive scarring, cirrhosis, and possibly liver cancer. We review concepts that are central to the pathogenesis of NASH.
Subject(s)
Disease Progression , Hepatocytes/metabolism , Lipid Metabolism , Lipids/toxicity , Non-alcoholic Fatty Liver Disease/etiology , Humans , Liver/cytology , Liver/metabolism , Non-alcoholic Fatty Liver Disease/metabolismABSTRACT
BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is the number one cause of chronic liver disease and second indication for liver transplantation in the Western world. Effective therapy is still not available. Previously we showed a critical role for caspase-2 in the pathogenesis of nonalcoholic steatohepatitis (NASH), the potentially progressive form of NAFLD. An imbalance between free coenzyme A (CoA) and acyl-CoA ratio is known to induce caspase-2 activation. OBJECTIVES: We aimed to evaluate CoA metabolism and the effects of supplementation with CoA precursors, pantothenate and cysteine, in mouse models of NASH. METHODS: CoA metabolism was evaluated in methionine-choline deficient (MCD) and Western diet mouse models of NASH. MCD diet-fed mice were treated with pantothenate and N-acetylcysteine or placebo to determine effects on NASH. RESULTS: Liver free CoA content was reduced, pantothenate kinase (PANK), the rate-limiting enzyme in the CoA biosynthesis pathway, was down-regulated, and CoA degrading enzymes were increased in mice with NASH. Decreased hepatic free CoA content was associated with increased caspase-2 activity and correlated with worse liver cell apoptosis, inflammation, and fibrosis. Treatment with pantothenate and N-acetylcysteine did not inhibit caspase-2 activation, improve NASH, normalize PANK expression, or restore free CoA levels in MCD diet-fed mice. CONCLUSION: In mice with NASH, hepatic CoA metabolism is impaired, leading to decreased free CoA content, activation of caspase-2, and increased liver cell apoptosis. Dietary supplementation with CoA precursors did not restore CoA levels or improve NASH, suggesting that alternative approaches are necessary to normalize free CoA during NASH.
Subject(s)
Acetylcysteine/pharmacology , Liver/drug effects , Non-alcoholic Fatty Liver Disease/drug therapy , Pantothenic Acid/pharmacology , Vitamin B Complex/pharmacology , Acyl Coenzyme A/metabolism , Animals , Apoptosis/drug effects , Caspase 2/metabolism , Choline Deficiency/complications , Diet, Western , Disease Models, Animal , Liver/metabolism , Liver/pathology , Liver Cirrhosis/drug therapy , Liver Cirrhosis/metabolism , Liver Cirrhosis/pathology , Male , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/etiology , Non-alcoholic Fatty Liver Disease/metabolism , Non-alcoholic Fatty Liver Disease/pathology , Phosphotransferases (Alcohol Group Acceptor)/metabolismABSTRACT
OBJECTIVE: The ductular reaction (DR) involves mobilisation of reactive-appearing duct-like cells (RDC) along canals of Hering, and myofibroblastic (MF) differentiation of hepatic stellate cells (HSC) in the space of Disse. Perivascular cells in stem cell niches produce pleiotrophin (PTN) to inactivate the PTN receptor, protein tyrosine phosphatase receptor zeta-1 (PTPRZ1), thereby augmenting phosphoprotein-dependent signalling. We hypothesised that the DR is regulated by PTN/PTPRZ1 signalling. DESIGN: PTN-GFP, PTN-knockout (KO), PTPRZ1-KO, and wild type (WT) mice were examined before and after bile duct ligation (BDL) for PTN, PTPRZ1 and the DR. RDC and HSC from WT, PTN-KO, and PTPRZ1-KO mice were also treated with PTN to determine effects on downstream signaling phosphoproteins, gene expression, growth, and migration. Liver biopsies from patients with DRs were also interrogated. RESULTS: Although quiescent HSC and RDC lines expressed PTN and PTPRZ1 mRNAs, neither PTN nor PTPRZ1 protein was demonstrated in healthy liver. BDL induced PTN in MF-HSC and increased PTPRZ1 in MF-HSC and RDC. In WT mice, BDL triggered a DR characterised by periportal accumulation of collagen, RDC and MF-HSC. All aspects of this DR were increased in PTN-KO mice and suppressed in PTPRZ1-KO mice. In vitro studies revealed PTN-dependent accumulation of phosphoproteins that control cell-cell adhesion and migration, with resultant inhibition of cell migration. PTPRZ1-positive cells were prominent in the DRs of patients with ductal plate defects and adult cholestatic diseases. CONCLUSIONS: PTN, and its receptor, PTPRZ1, regulate the DR to liver injury by controlling the migration of resident cells in adult liver progenitor niches.