Burden of pediatric hepatitis C

Hepatitis C virus(HCV)is a major health burden infecting 170-210 million people worldwide.Additional 3-4millions are newly-infected annually.Prevalence of pediatric infection varies from 0.05%-0.36%in the United States and Europe;up to 1.8%-5.8%in some developing countries.The highest prevalence occurs in Egypt,sub-Saharan Africa,Amazon basin and Mongolia.HCV has been present in some populations for several centuries,notably genotypes 1 and 2 in West Africa.Parenteral anti-schistosomal therapy practiced in the 1960s until the early 1980s had spread HCV infection throughout Egypt.Parenteral acquisition of HCV remains a major route for infection among Egyptian children.Insufficient screening of transfusions,unsterilized injection equipment and re-used needles and syringes continue to be major routes of HCV transmission in developing countries,whereas vertical transmission and adolescent high-risk behaviors(e.g.,injection drug abuse)are the major routes in developed countries.The risk of vertical transmission from an infected mother to her unborn/newborn infant is approximately 5%.Early stages of HCV infection in children do not lead to marked impairment in the quality of life nor to cognitive,behavioral or emotional dysfunction;however,caregiver stress and family system strain may occur.HCV slowly progresses to serious complications as cirrhosis(1%-2%)and hepatocellular carcinoma(HCC)especially in the presence of risk factors as hemolytic anemias,obesity,treated malignancy,and concomitant human immune deficiency and/or hepatitis B virus co-infection.HCV vaccine remains elusive to date.Understanding the immune mechanisms in patients who successfully cleared the infection is essential for vaccine development.The pediatric standard of care treatment consists of pegylated interferon-α2a or b plus ribavirin for 24-48 wk.The new oral direct acting antivirals,approved for adults,need further evaluation in children.Sustained virologic response varies depending on the viral load,genotype,duration of infection,degree of aminotransferase elevation,adiposity and single nucleotide polymorphisms of interleukin(IL)-28B locus.The goals of treatment in individual patients are virus eradication,prevention of cirrhosis and HCC,and removing stigmatization;meanwhile the overall goal is decreasing the global burden of HCV.IL-28B polymorphisms have been also associated with spontaneous clearance of vertically acquired HCV infection.The worldwide economic burden of HCV for children,families and countries is estimated to be hundreds of millions of US dollars per year.The United States,alone,is estimated to spend 199-336 million dollars in screening,monitoring and treatment during one decade.The emotional burden of having an HCV infected child in a family is more difficult to estimate.

Pediatric hepatocellular carcinoma

Pediatric hepatocellular carcinoma (HCC) is the second common malignant liver tumor in children after hepato-blastoma. It differs from the adult HCC in the etiological predisposition, biological behavior and lower frequency of cirrhosis. Perinatally acquired hepatitis-B virus, hepa-torenal tyrosinemia, progressive familial intrahepatic cho-lestasis, glycogen storage disease, Alagille's syndrome and congenital portosystemic shunts are important predis-posing factors. Majority of children (87%) are older than 5 years of age. Following mass immunization against hepatitis-B, there has been a drastic fall in the incidence of new cases of pediatric HCC in the Asia-Pacific region. Management is targeted on complete surgical removal either by resection or liver transplantation. There is a trend towards improving survival of children transplanted for HCC beyond Milan criteria. Chemotherapeutic regi-mens do not offer good results but may be helpful for down-staging of advanced HCC. Surveillance of children with chronic liver diseases with ultrasound and alpha-fetoprotein may be helpful in timely detection, intervention and overall improvement in outcome of HCC.

Transient elastography compared to liver biopsy and morphometry for predicting fibrosis in pediatric chronic liver disease: Does etiology matter?

AIM: To evaluate transient elastography (TE) as a noninvasive tool in staging liver fibrosis compared with liver biopsy and morphometry in children with different chronic liver diseases.METHODS: A total of 90 children [50 with chronic hepatitis C virus (HCV), 20 with autoimmune hepatitis (AIH) and 20 with Wilson disease] were included in the study and underwent liver stiffness measurement (LSM) using TE. Liver biopsies were evaluated for fibrosis, qualitatively, by Ishak score and quantitatively by fibrosis area fraction (FAF) using digital image analysis (morphometry). LSM was correlated with fibrosis and other studied variables using spearman correlation. A stepwise multiple regression analysis was also performed to examine independent factors associated with LSM. Different cut-off values of LSM were calculated for predicting individual fibrosis stages using receiver-operating characteristic curve. Cut-off values with optimal clinical performance (optimal sensitivity and specificity simultaneously) were selected.RESULTS: The majority of HCV group had minimal activity (80%) and no/mild fibrosis (72%). On the other hand, the majority of AIH group had mild to moderate activity (70%) and moderate to severe fibrosis (95%) and all Wilson disease group had mild to moderate activity (100%) and moderate to severe fibrosis (100%). LSM correlated significantly with both FAF and Ishak scores and the correlation appeared better with the latter (r = 0.839 vs 0.879, P < 0.0001 for both). LSM discriminated individual stages of fibrosis with high performance. Sensitivity ranged from 81.4% to 100% and specificity ranged from 75.0% to 97.2%. When we compared LSM values for the same stage of fibrosis, they varied according to the different etiologies. Higher values were in AIH (16.15 ± 7.23 kPa) compared to Wilson disease (8.30 ± 0.84 kPa) and HCV groups (7.43 ± 1.73 kPa). Multiple regression analysis revealed that Ishak fibrosis stage was the only independent variable associated with higher LSM (P < 0.0001).CONCLUSION: TE appears reliable in distinguishing different stages of liver fibrosis in children. However, its values vary according to the disease type. For that, a disease-specific estimation of cut-off values for fibrosis staging is worthy.

Intestinal ascariasis at pediatric emergency room in a developed country

Ascaris lumbricoides infection is rare among children in developed countries.Although large numbers of adult Ascaris in the small intestine can cause various abdominal symptoms,this infection remains asymptomatic until the number of worms in the intestine considerably increases in most cases.Ascaris causing bilious vomiting suggesting ileus is rare,especially in developed countries.A 6-year-old boy who lived in Japan,presented with abdominal colic,bilious vomiting at the pediatric emergency room.He appeared pale,and had no abdominal distention,tenderness,palpable abdominal mass,or findings of dehydration.He experienced bilious vomiting again during a physical examination.Laboratory tests showed mild elevation of white blood cells and C-reactive protein levels.Antigens of adenovirus,rotavirus,and norovirus were not detected from his stool,and stool culture showed normal flora.Ultrasonography showed multiple,round-shaped structures within the small intestine,and a tubular structure in a longitudinal scan of the small intestine.Capsule endoscopy showed a moving worm of Ascaris in the jejunum.Intestinal ascariasis should be considered as a cause of bilious vomiting in children,even at the emergency room in industrial countries.Ultrasound examination and capsule endoscopy are useful for diagnosis of pediatric intestinal ascariasis.

Serum proinflammatory cytokines and nutritional status in pediatric chronic liver disease

AIM: To evaluate the nutritional status and its association with proinflammatory cytokines in children with chronic liver disease.METHODS: We performed a cross-sectional study with 43 children and adolescents, aged 0 to 17 years, diagnosed with chronic liver disease. All patients regularly attended the Pediatric Hepatology Unit and were under nutritional follow up. The exclusion criteria were fever from any etiology at the time of enrollment, inborn errors of the metabolism and any chronic illness. The severity of liver disease was assessed by Child-Pugh, Model for End-stage Liver Disease(MELD) and Pediatric End Stage Liver Disease(PELD) scores. Anthropometric parameters were height/age, body mass index/age and triceps skinfold/age according to World Health Organization standards. The cutoff points for nutritional status were risk of malnutrition(Z-score <-1.00) and malnutrition(Z-score <-2.00). Interleukin-1β(IL-1β), IL-6 and tumor necrosis factor-α levels were assessed by commercial ELISA kits. For multivariate analysis, linear regression was applied to assess the association between cytokine levels, disease severity and nutritional status. RESULTS: The median(25th-75 th centile) age of the study population was 60(17-116)-mo-old, and 53.5% were female. Biliary atresia was the main cause of chronic liver disease(72%). With respect to Child-Pugh score, cirrhotic patients were distributed as follows: 57.1% Child-Pugh A, a mild presentation of the disease, 34.3% Child-Pugh B, a moderate stage of cirrhosis and 8.6% Child-Pugh C, were considered severe cases. PELD and MELD scores were only above the cutoff point in 5 cases. IL-6 values were increased in patients at nutritional risk(34.9%) compared with those who were well-nourished [7.12(0.58-34.23) pg/m L vs 1.63(0.53-3.43) pg/m L; P = 0.02], correlating inversely with triceps skinfold-for-age z-score(rs =-0.61; P < 0.001). IL-6 levels were associated with liver disease severity assessed by Child-Pugh score(P = 0.001). This association remained significant after adjusting for nutritional status in a linear regression model. CONCLUSION: High IL-6 levels were found in children with chronic liver disease at nutritional risk. Inflammatory activity may be related to nutritional status deterioration in these patients.

Impact of donor-specific antibodies on long-term graft survival with pediatric liver transplantation

BACKGROUND In a previous paper,we reported a high prevalence of donor-specific antibody(DSA)in pediatric patients with chronic rejection and expressed the need for confirmation of these findings in a larger cohort.AIM To clarify the importance of DSAs on long-term graft survival in a larger cohort of pediatric patients.METHODS We performed a retrospective analysis of 123 pediatric liver transplantation(LT)recipients who participated in yearly follow-ups including Luminex testing for DSA at our center.The cohort was split into two groups according to the DSA status(DSA-positive n=54,DSA-negative n=69).Groups were compared with regard to liver function,biopsy findings,graft survival,need for re-LT and immunosuppressive medication.RESULTS DSA-positive pediatric patients showed a higher prevalence of chronic rejection(P=0.01),fibrosis(P<0.001)and re-transplantation(P=0.018)than DSA-negative patients.Class II DSAs particularly influenced graft survival.Alleles DQ2,DQ7,DQ8 and DQ9 might serve as indicators for the risk of chronic rejection and/or allograft fibrosis.Mean fluorescence intensity levels and DSA number did not impact graft survival.Previous episodes of chronic rejection might lead to DSA development.CONCLUSION DSA prevalence significantly affected long-term liver allograft performance and liver allograft survival in our cohort of pediatric LT.Screening for class II DSAs in combination with assessment of protocol liver biopsies for chronic antibodymediated rejection improved early identification of patients at risk of graft loss.

Current therapy of pediatric Crohn's disease

Inflammatory bowel diseases(IBD), including Crohn's disease(CD) and ulcerative colitis, are chronic relapsing and remitting diseases of the bowel, with an unknown etiology and appear to involve interaction between genetic susceptibility, environmental factors and the immune system. Although our knowledge and understanding of the pathogenesis and causes of IBD have improved significantly, the incidence in the pediatric population is still rising. In the last decade more drugs and treatment option have become available including 5-aminosalicylate,antibiotics, corticosteroids, immunomodulators and biological agents. Before the use of anti-tumor necrosis factor(TNF)-α became available to patients with IBD, the risk for surgery within five years of diagnosis was very high, however, with anti-TNF-α treatment the risk of surgery has decreased significantly. In the pediatric population a remission in disease can be achieved by exclusive enteral nutrition. Exclusive enteral nutrition also has an important role in the improvement of nutritional status and maintained growth. In this review we summarize the current therapeutic treatments in CD. The progress in the treatment options and the development of new drugs has led to optimized tactics for achieving the primary clinical goals of therapy- induction and maintenance of remission while improving the patient's growth and overall well-being.

Breakthroughs and challenges in the management of pediatric viral hepatitis

Chronic infections by hepatitis B virus(HBV)and hepatitis C virus(HCV)major causes of advanced liver disease and mortality worldwide.Although regarded as benign infections in children,their persistence through adulthood is undoubtedly of concern.Recent advances in HCV treatment have restored the visibility of these conditions and raised expectations for HBV treatment,which is currently far from being curative.Herein we describe direct-acting antivirals available for pediatric HCV(sofosbuvir/ledipasvir,sofosbuvir/velpatasvir,glecaprevir/pibrentasvir)and their real-world use.A critical review of the HBV pediatric classification is provided.Anti-HBV investigational compounds are reviewed in light of the pathophysiology in the pediatric population,including capsid assembly modulators,antigen secretion inhibitors,silencing RNAs,and immune modifiers.Recommendations for screening and management of immunosuppressed children or those with other risk factors or comorbidities are also summarized.

Transient elastography and diffusion-weighted magnetic resonance imaging for assessment of liver fibrosis in children with chronic hepatitis C

BACKGROUND Chronic hepatitis C(CHC)is a health burden with consequent morbidity and mortality.Liver biopsy is the gold standard for evaluating fibrosis and assessing disease severity and prognostic purposes post-treatment.Noninvasive altern-atives for liver biopsy such as transient elastography(TE)and diffusion-weighted magnetic resonance imaging(DW-MRI)are critical needs.AIM To evaluate TE and DW-MRI as noninvasive tools for predicting liver fibrosis in children with CHC.METHODS This prospective cross-sectional study initially recruited 100 children with CHC virus infection.Sixty-four children completed the full set of investigations including liver stiffness measurement(LSM)using TE and measurement of apparent diffusion coefficient(ADC)of the liver and spleen using DW-MRI.Liver biopsies were evaluated for fibrosis using Ishak scoring system.LSM and liver and spleen ADC were compared in different fibrosis stages and correlation analysis was performed with histopathological findings and other laboratory parameters.RESULTS Most patients had moderate fibrosis(73.5%)while 26.5%had mild fibrosis.None had severe fibrosis or cirrhosis.The majority(68.8%)had mild activity,while only 7.8%had moderate activity.Ishak scores had a significant direct correlation with LSM(P=0.008)and were negatively correlated with both liver and spleen ADC but with no statistical significance(P=0.086 and P=0.145,respectively).Similarly,histopatho-logical activity correlated significantly with LSM(P=0.002)but not with liver or spleen ADC(P=0.84 and 0.98 respectively).LSM and liver ADC were able to significantly discriminate F3 from lower fibrosis stages(area under the curve=0.700 and 0.747,respectively)with a better performance of liver ADC.CONCLUSION TE and liver ADC were helpful in predicting significant fibrosis in children with chronic hepatitis C virus infection with a better performance of liver ADC.

Use of mesenchymal stem cells to treat liver fibrosis:Current situation and future prospects

Progressive liver fibrosis is a major health issue for which no effective treatment is available,leading to cirrhosis and orthotopic liver transplantation.However,organ shortage is a reality.Hence,there is an urgent need to find alternative therapeutic strategies.Cellbased therapy using mesenchymal stem cells(MSCs) may represent an attractive therapeutic option,based ontheir immunomodulatory properties,their potential to differentiate into hepatocytes,allowing the replacement of damaged hepatocytes,their potential to promote residual hepatocytes regeneration and their capacity to inhibit hepatic stellate cell activation or induce their apoptosis,particularly via paracrine mechanisms.The current review will highlight recent findings regarding the input of MSC-based therapy for the treatment of liver fibrosis,from in vitro studies to pre-clinical and clinical trials.Several studies have shown the ability of MSCs to reduce liver fibrosis and improve liver function.However,despite these promising results,some limitations need to be considered.Future prospects will also be discussed in this review.

Stem cells for liver tissue repair:Current knowledge and perspectives

Stem cells from extra-or intrahepatic sources have been recently characterized and their usefulness for the generation of hepatocyte-like lineages has been demonstrated. Therefore, they are being increasingly considered for future applications in liver cell therapy. In that field, liver cell transplantation is currently regarded as a possible alternative to whole organ transplantation, while stem cells possess theoretical advantages on hepatocytes as they display higher in vitro culture performances and could be used in autologous transplant procedures. However, the current research on the hepatic fate of stem cells is still facing difficulties to demonstrate the acquisition of a full mature hepatocyte phenotype, both in vitro and in vivo. Furthermore, the lack of obvious demonstration of in vivo hepatocyte-like cell functionality remains associated to low repopulation rates obtained after current transplantation procedures. The present review focuses on the current knowledge of the stem cell potential for liver therapy. We discuss the characteristics of the principal cell candidates and the methods to demonstrate their hepatic potential in vitro and in vivo. We finally address the question of the future clinical applications of stem cells for liver tissue repair and the technical aspects that remain to be investigated.

Hepatic fibrosis： It is time to go with hepatic stellate cell-specifictherapeutic targets

Hepatic fibrosis is a pathological lesion, characterized by the progressive accumulation of extracellularmatrix （ECM） in the perisinusoidal space and it is a major problem in chronic liver diseases. Phenotypicactivation of hepatic stellate cells （HSC） plays a central role in the progression of hepatic fibrosis. Retardation of proliferation and clearance of activated HSCs from the injured liver is an appropriate therapeuticstrategy for the resolution and treatment of hepatic fibrosis. Clearance of activated HSCs from the injuredliver by autophagy inhibitors, proapoptotic agents and senescence inducers with the high affinity towardthe activated HSCs may be the novel therapeutic strategy for the treatment of hepatic fibrosis in the nearfuture.

Safety and utility of capsule endoscopy for infants and young children

AIM:To assess the safety and utility of capsule endoscopy(CE)for children who are unable to swallow the capsule endoscope.METHODS:The medical records of all of the children who underwent CE between 2010 and 2012 were retrospectively reviewed.The patients were divided into 2groups:group A included patients who were unable to swallow the capsule endoscope,and group B included patients who were able to swallow it.For the patients who were unable to swallow the capsule endoscope,it was placed in the duodenum endoscopically.The small bowel transit time,endoscopic diagnosis and complications of the 2 groups were compared.RESULTS:During the study period,28 CE procedures were performed in 26 patients.Group A included 11patients with a median age of 2 years(range 10 mo-9years),and group B included 15 patients with a median age of 12 years(range 8 years-16 years).The lightest child in the study weighed 7.9 kg.The detection rates did not differ between the 2 groups.The median small bowel transit time was 401 min(range 264-734 min)in group A and 227 min(range 56-512 min)in group B(P=0.0078).No serious complications,including capsule retention,occurred.No significant mucosal trauma occurred in the pharynx,esophagus,stomach or duodenum when the capsule was introduced using an endoscope.CONCLUSION:CE is a safe and useful procedure for infants and young children who are unable to swallow the capsule endoscope.

Liver cell transplantation for Crigler-Najjar syndrome type Ⅰ: Update and perspectives

Liver cell transplantation is an attractive technique to treat liver-based inborn errors of metabolism. The feasibility and efficacy of the procedure has been demonstrated, leading to medium term partial metabolic control of various diseases. Crigler-Najjar is the paradigm of such diseases in that the host liver is lacking one function with an otherwise normal parenchyma. The patient is at permanent risk for irreversible brain damage. The goal of liver cell transplantation is to reduce serum bilirubin levels within safe limits and to alleviate phototherapy requirements to improve quality of life. Preliminary data on Gunn rats, the rodent model of the disease, were encouraging and have led to successful clinical trials. Herein we report on two additional patients and describe the current limits of the technique in terms of durability of the response as compared to alternative therapeutic procedures. We discuss the future developments of the technique and new emerging perspectives.

SOX9 in biliary atresia: New insight for fibrosis progression

Background:Liver fibrosis is a hallmark determinant of morbidity in biliary atresia(BA)even in successfully operated cases.Responsible factors for this rapid progression of fibrosis are not completely defined.Aberrant expression of the transcription factor SOX9 and hepatic progenitor cells(HPCs)proliferation have roles in fibrogenesis in cholestatic disorders.However,they were not investigated sufficiently in BA.We aimed to delineate the relation of SOX9 and HPCs to fibrosis and its progression in BA.Methods:Forty-eight patients with BA who underwent an initial diagnostic liver biopsy(LB)and consequent intraoperative LB were recruited and compared to 28 cases with non-BA cholestasis that had an LB in their diagnostic workup.Liver fibrosis,tissue SOX9 and HPC expressions were studied in both BA and non-BA-cholestasis cases.Liver fibrosis,SOX9,and HPCs’dynamic changes in BA cases were assessed.Relation of fibrosis and its progression to SOX9 and HPCs in BA was assessed.Results:SOX9 and HPCs in ductular reaction(DR)form were expressed in 100%of BA and their grades increased significantly in the second biopsy.The rapidly progressive fibrosis in BA,represented by fibrosis grade of the intraoperative LB,correlated significantly to SOX9-DR and HPC-DR at the diagnostic(r=0.420,P=0.003 and r=0.405,P=0.004,respectively)and the intraoperative(r=0.460,P=0.001 and r=0.467,P=0.001,respectively)biopsy.On the other hand,fibrosis,SOX9-DR,and HPC-DR were significantly lower in non-BA cases at a comparable age(P<0.001,P=0.006,and P=0.014,respectively).Conclusions:Fibrosis in BA is rapidly progressive within a short time and is significantly correlated to SOX9 and HPCs.Assessment of targeting SOX9 and HPCs on fibrosis progression is warranted.

Management of portal hypertension in children

Portal hypertension can be caused by a wide variety of conditions.It frequently presents with bleeding from esophageal varices.The approach to acute variceal hemorrhage in children is a stepwise progression from least invasive to most invasive.Management of acute variceal bleeding is straightforward.But data on primary prophylaxis and long term management prevention of recurrent variceal bleeding in children is scarce,therefore prospective multicenter trials are needed to establish best practices.

Neurological manifestations of hepatitis E virus infection:An overview

Hepatitis E virus(HEV)is an important cause of repeated waterborne outbreaks of acute hepatitis.Recently,several extrahepatic manifestations(EHMs)have been described in patients with HEV infection.Of these,neurological disorders are the most common EHM associated with HEV.The involvement of both the peripheral nervous system and central nervous system can occur together or in isolation.Patients can present with normal liver function tests,which can often be misleading for physicians.There is a paucity of data on HEV-related neurological manifestations;and these data are mostly described as case reports and case series.In this review,we analyzed data of 163 reported cases of HEV-related neurological disorders.The mechanisms of pathogenesis,clinico-demographic profile,and outcomes of the HEV-related neurological disorders are described in this article.Nerve root and plexus disorder were found to be the most commonly reported disease,followed by meningoencephalitis.

Serum complement C4a and its relation to liver fibrosis in children with chronic hepatitis C

AIM:To evaluate serum complement C4a and its relation to liver fibrosis in children with chronic hepatitis C virus(HCV)infection.METHODS:The study included 30 children with chronic HCV infection before receiving antiviral therapy.Chronic HCV infection was defined by positive anti-HCV,a positive polymerase chain reaction for HCV-RNA for more than 6 mo with absence of any associated liver disease.A second group of 30 age-and sex-matched healthy children served as controls.Serum C4a levels were measured by enzyme-linked immunosorbent assay.Liver fibrosis stage and inflammatory grade were assessed using Ishak scoring system.Serum C4a levels were compared according to different clinical,laboratory and histopathological parameters.Statistical significance for quantitative data was tested by MannWhitney U non-parametric tests.For qualitative data,significance between groups was tested by 2test.Correlation was tested by Spearman’s test.Results were considered significant if P value≤0.05.RESULTS:The age of the patients ranged from 3.5to 18 years and that of controls ranged from 4 to 17years.C4a mean levels were merely lower in patients(153.67±18.69 mg/L)than that in the controls(157.25±11.40 mg/L)with no statistical significance(P=0.378).It did not differ significantly in patients with elevated vs those with normal transaminases(152.25±16.62 vs 155.36±21.33;P=0.868)or with different HCV viremia(P=0.561).Furthermore,there was no statistical significant difference in serum levels between those with no/mild fibrosis and those with moderate fibrosis(154.65±20.59 vs 152.97±17.72;P=0.786)or minimal and mild activity(155.1±21.93 vs 152.99±17.43;P=0.809).Though statistically not significant,C4a was highest in fibrosis score 0(F0),decreasing in F1 and F2 to be the lowest in F3.When comparing significant fibrosis(Ishak score≥3)vs other stages,C4a was significantly lower in F3 compared to other fibrosis scores(143.55±2.33 mg/L vs 155.26±19.64 mg/L;P=0.047)and at a cutoff value of less than 144.01 mg/L,C4a could discriminate F3 with 76.9%sensitivity and75%specificity from other stages of fibrosis.CONCLUSION:Serum complement C4a did not correlate with any of transaminases,HCV viremia or with the histopathological scores.Although C4a decreased with higher stages of fibrosis,this change was not significant enough to predict individual stages of fibrosis.Yet,it could predict significant fibrosis with acceptable clinical performance.

Epithelial cells with hepatobiliary phenotype:Is it another stem cell candidate for healthy adult human liver?

AIM： To investigate the presence and role of liver epithelial cells in the healthy human adult liver. METHODS： Fifteen days after human hepatocyte primary culture, epithelial like cells emerged and started proliferating. Cell colonies were isolated and sub- cultured for more than 160 d under specific culture conditions. Cells were analyzed for each passage using immunofluorescence, flow cytometry and reverse transcription-polymerase chain reaction （RT-PCR）. RESULTS： Flow cytometry analysis demonstrated that liver epithelial cells expressed common markers for hepatic and stem cells such as CD90, CD44 and CD29 but were negative for CD34 and CDl17. Using immunofluorescence we demonstrated that liver epithelial cells expressed not only immature （α-fetoprotein） but also differentiated hepatocyte （albumin and CK-18） and biliary markers （CK-7 and 19）, whereas they were negative for OV-6. RT-PCR analysis confirmed immunofluorescence data and revealed that liver epithelial cells did not express mature hepatocyte markers such as CYP2B6, CYP3A4 and tyrosine amino-transferase. Purified liver epithelial cells were transplanted into SCID mice. One month after transplantation, albumin positive cell foci were detected in the recipient mouse parenchyma. CONCLUSION： According to their immature and bipotential phenotype, liver epithelial cells might represent a pool of precursors in the healthy human adult liver other than oval cells.

Silibinin induces hepatic stellate cell cycle arrest via enhancing p53/p27 and inhibiting Akt downstream signaling protein expression

BACKGROUND： Proliferation of hepatic stellate cells （HSCs） plays a pivotal role in the progression of liver fibrosis conse- quent to chronic liver injury. Silibinin, a flavonoid compound, has been shown to possess anti-fibrogenic effects in animal models of liver fibrosis. This was attributed to an inhibition of cell proliferation of activated HSCs. The present study was to gain insight into the molecular pathways involved in silibinin anti-fibrogenic effect. METHODS： The study was conducted on LX-2 human stellate cells treated with three concentrations of silibinin （10, 50 and 100 μmol/L） for 24 and 96 hours. At the end of the treatment cell viability and proliferation were evaluated. Protein expression of p27, p21, p53, Akt and phosphorylated-Akt was evaluated by Western blotting analysis and Ki-67 protein expression was by immunocytochemistry. Sirtuin activity was evaluated by chemiluminescence based assay. RESULTS： Silibinin inhibits LX-2 cell proliferation in doseand time-dependent manner; we showed that silibinin upregulated the protein expressions of p27 and p53. Such regulation was correlated to an inhibition of both downstream Akt and phosphorylated-Akt protein signaling and Ki-67 protein expression. Sirtuin activity also was correlated to silibinin- inhibited proliferation of LX-2 cells. CONCLUSION： The anti-proliferative effect of silibinin on LX-2 human steUate cells is via the inhibition of the expres- sions of various cell cycle targets including p27, Akt and sir- tuin signaling.