Proposal of fibrosis index using image analyzer as a quantitative histological evaluation of liver fibrosis in biliary atresia

Quantification of Liver Fibrosis—A Comparative Study

Liver disease has been targeted as the fifth most common cause of death worldwide and tends to steadily rise. In the last three decades, several publications focused on the quantification of liver fibrosis by means of the estimation of the collagen proportional area (CPA) in liver biopsies obtained from digital image analysis (DIA). In this paper, early and recent studies on this topic have been reviewed according to these research aims: the datasets used for the analysis, the employed image processing techniques, the obtained results, and the derived conclusions. The purpose is to identify the major strengths and “gray-areas” in the landscape of this topic.

Quantitative Liver Fibrosis Using Collagen Hybridizing Peptide to Predict Native Liver Survival in Biliary Atresia: A Pilot Study

BACKGROUND/RATIONALE

Biliary atresia (BA) is a cholangiopathy characterized by bile flow obstruction due to destruction of the biliary tree. Without surgical correction with Kasai portoenterostomy (KPE), BA leads to death or liver transplant (LTx). Early-onset, progressive liver fibrosis is a defining characteristic of BA. Collagen hybridizing peptide (CHP) is a synthetic peptide which binds to denatured collagen strands allowing quantification of fibrosis. This technique has not been used on human liver tissue. The aim of this pilot study was to evaluate the utility of CHP as a measurement of quantitative fibrosis to allow earlier survival with native liver prognostication.

RESULTS

We identified 21 patients with wedge liver biopsies available, of which 14 required LTx. No deaths occurred. Patients requiring LTx tended to be girls with a significantly different mean bilirubin (P = 0.002), albumin (P = 0.001), and alanine aminotransferase (P = 0.03) at 3 months post-KPE. By 1 year post-KPE, 50% of patients in the high CHP intensity group required LTx versus 27% in the low CHP. Overall, fibrosis as quantified by CHP at time of KPE was associated with more than 3 times the risk of requiring LTx by 4 years of age (hazard ratio 3.6, 95% confidence interval 1.15-10.93, P = 0.03). When controlling for sex and total bilirubin >2 mg/dL and albumin at 3 months post-KPE, it predicted nearly 7 times the risk of LTx (hazard ratio 6.89, 95% confidence interval 1.38-34.32, P = 0.02).

CONCLUSION

Our results suggest that quantitative assessment of fibrosis at the time of KPE holds promise as an earlier predictor of LTx requirement in BA. A larger study is justified to assess quantitative fibrosis as a BA prognostic tool.

Inhibition of the Activin Receptor Type-2B Pathway Restores Regenerative Capacity in Satellite Cell-Depleted Skeletal Muscle

Degenerative myopathies typically display a decline in satellite cells coupled with a replacement of muscle fibers by fat and fibrosis. During this pathological remodeling, satellite cells are present at lower numbers and do not display a proper regenerative function. Whether a decline in satellite cells directly contributes to disease progression or is a secondary result is unknown. In order to dissect these processes, we used a genetic model to reduce the satellite cell population by ~70–80% which leads to a nearly complete loss of regenerative potential. We observe that while no overt tissue damage is observed following satellite cell depletion, muscle fibers atrophy accompanied by changes in the stem cell niche cellular composition. Treatment of these mice with an Activin receptor type-2B (AcvR2B) pathway blocker reverses muscle fiber atrophy as expected, but also restores regenerative potential of the remaining satellite cells. These findings demonstrate that in addition to controlling fiber size, the AcvR2B pathway acts to regulate the muscle stem cell niche providing a more favorable environment for muscle regeneration.

Transplantation of Human Amniotic Membrane over the Liver Surface Reduces Hepatic Fibrosis in a Cholestatic Model in Young Rats

Purpose

Biliary atresia precedes liver cirrhosis and liver transplantation. Amniotic membrane (AM) promotes tissue regeneration, inhibits fibrosis, and reduces inflammation. Here, we test amniotic membrane potential as a therapeutic tool against cholestatic liver fibrosis.

Methods

Three groups of rats were used: sham surgery (SS), bile duct ligature (BDL), and bile duct ligature plus human amniotic membrane (BDL + AM). After surgery, animals were sacrificed at different weeks. Biochemical and histopathological analyses of liver tissue were performed. Collagen was expressed as a percentage of total liver tissue area. qPCR was performed to analyse gene expression levels of transforming growth factor-β1 (Tgfb1) and apelin (Apln). Statistical analysis performed considered p < 0.05 was significant.

Results

Groups undergoing BDL developed cholestasis. Biochemical markers from BDL + AM group improved compared to BDL group. Ductular reaction, portal fibrosis, and bile plugs were markedly reduced in the BDL + AM group compared to BDL group. Collagen area in BDL + AM group was statistically decreased compared to BDL group. Finally, expression levels of both Apln and Tgfb1 mRNA were statistically downregulated in BDL + AM group versus BDL group.

Conclusion

AM significantly reduces liver fibrosis in a surgical animal model of cholestasis. Our results suggest that AM may be useful as a therapeutic tool in liver cirrhosis.

The limited prognostic value of liver histology in children with biliary atresia

Background and rationale for the study. The aim of the study was to determine the prognostic value of histopathological findings with special care to the severity of liver fibrosis at the moment of hepatoportoenterostomy (HPE) in children with biliary atresia (BA). We performed analysis of 142 wedge liver biopsies taken at the time of HPE. All patients were operated by the same surgical team between 1995 and 2007. According to the outcome 6 months after HPE patients were divided into prognostic groups: group 1-bilirubin level < 2 mg% (n = 65), group 2-bilirubin level > 2 mg% (n = 77). Liver biopsies were re-evaluated according to the extended histopathological protocol and then were compared between the prognostic groups. Survival with native liver (SNL) estimates were performed in regard to severity of liver fibrosis.

RESULTS

Survival with native liver estimates after 2, 5 and 10 years in patients after successful operation were 96%, 91%, 75% vs. 30%, 11%, and 5% if operation failed (p < 0.001). There was no difference between groups in the following variables: fibrosis (p = 0.69), portal inflammation (p = 0.99), lobular inflammation (p = 0.95), cholangiolitis (p = 0.23), accumulation of bile pigments (zone 1:p = 0.49; zone 2:p = 0.51; zone 3:p = 0.48), bile plugs in canaliculi (p = 0.12), bile plugs in ducts (p = 0.32), bilirubinostasis in hepatocytes (p = 0.45), bile ductular proliferation (p = 0.59), ductal plate malformation (p = 0.12), focal necrosis (p = 0.44), giant cell transformation (p = 0.45), haematopoesis (p = 0.52), ductopenia (p = 0.46), microabscesses (p = 0.49), ballooning of hepatocytes (p = 0.08). The actuarial 5/10-year SNL was not dependent on severity of liver fibrosis (log-rank test p = 0.84). The severity of fibrosis corresponded neither with the age at HPE nor with the laboratory findings before operation but increased the risk of portal hypertension.

CONCLUSION

Liver histology at the time of HPE is of limited value in prognosis making in BA.

Premature expression of a muscle fibrosis axis in chronic HIV infection

Background

Despite the success of highly active antiretroviral therapy (HAART), HIV infected individuals remain at increased risk for frailty and declines in physical function that are more often observed in older uninfected individuals. This may reflect premature or accelerated muscle aging.

Methods

Skeletal muscle gene expression profiles were evaluated in three uninfected independent microarray datasets including young (19 to 29 years old), middle aged (40 to 45 years old) and older (65 to 85 years old) subjects, and a muscle dataset from HIV infected subjects (36 to 51 years old). Using Bayesian analysis, a ten gene muscle aging signature was identified that distinguished young from old uninfected muscle and included the senescence and cell cycle arrest gene p21/Cip1 (CDKN1A). This ten gene signature was then evaluated in muscle specimens from a cohort of middle aged (30 to 55 years old) HIV infected individuals. Expression of p21/Cip1 and related pathways were validated and further analyzed in a rodent model for HIV infection.

Results

We identify and replicate the expression of a set of muscle aging genes that were prematurely expressed in HIV infected, but not uninfected, middle aged subjects. We validated select genes in a rodent model of chronic HIV infection. Because the signature included p21/Cip1, a cell cycle arrest gene previously associated with muscle aging and fibrosis, we explored pathways related to senescence and fibrosis. In addition to p21/Cip1, we observed HIV associated upregulation of the senescence factor p16INK4a (CDKN2A) and fibrosis associated TGFβ1, CTGF, COL1A1 and COL1A2. Fibrosis in muscle tissue was quantified based on collagen deposition and confirmed to be elevated in association with infection status. Fiber type composition was also measured and displayed a significant increase in slow twitch fibers associated with infection.

Conclusions

The expression of genes associated with a muscle aging signature is prematurely upregulated in HIV infection, with a prominent role for fibrotic pathways. Based on these data, therapeutic interventions that promote muscle function and attenuate pro-fibrotic gene expression should be considered in future studies.

Liver fibrosis in biliary atresia

Biliary atresia (BA) is the most common cholestatic liver disorder requiring liver transplantation in children. Hepatic fibrosis is not only a universal and prominent feature of BA, it is also the most important predictor of outcome following portoenterostomy (PE). Without PE, the progression of hepatic fibrosis is quite dramatic, such that liver cirrhosis is established within a few weeks after birth. Etiologies and molecular networks underpinning such an expeditious fibrogenic process have not been well established. However, immune and nonimmune factors implicated in the pathogenesis of BA, and the resultant cholestasis and oxidative stress, appear to be the main triggers of hepatic fibrosis in BA. Owing to a lack of validated noninvasive tools to monitor liver fibrosis, current prognostic models of BA entail clinical and biochemical variables reflecting liver dysfunction rather than hepatic fibrogenesis. Further work is necessary to validate the results of preliminary studies indicating a good relationship between liver fibrosis determined by transient elastography and other clinical and routinely performed biochemical parameters in pediatric patients. Although a prime candidate for a number of antifibrotic therapies on the horizon, owing to poor understanding of molecular mechanisms, a clear framework of antifibrotic targets has not been outlined in BA. Similarly, specific antifibrotic therapies have not yet been incorporated in clinical practice, limiting these measures to prompt diagnosis and PE operation, prevention and treatment of cholangitis and optimal nutritional support including the administration of fat-soluble vitamins.

Prognostic value of computerized quantification of liver fibrosis in children with biliary atresia

Biliary atresia (BA) is the leading indication for liver transplantation (LTx) during childhood. Predictive markers for progression are lacking. We investigated the correlation between quantified fibrosis of the liver at the time of Kasai hepatic portoenterostomy (KPE) and the clinical course. Liver tissue was obtained at the time of KPE in 53 children and stained with Picrosirius red. The mean volume of fibrosis per number of periportal fields (Vfib) and the Ishak score were calculated. Vfib was 3.9%. Transplant-free survival was significantly higher in those patients with Vfib < 2.5% (P < 0.05, Kaplan-Meier analysis). Vfib < 2.5% predicted transplant-free survival with a sensitivity of 100% and a specificity of 48% (positive predictive value: 100%, negative predictive value: 17%). Vfib was correlated with bilirubin 6 months after KPE (Bili6m). The negative predictive value could be enhanced to 23% if Vfib < 2.5% was combined with Bili6m < 20 micromol/L. The Ishak score showed no correlation with transplant-free survival or Vfib. Detection of Vfib at the time of KPE is a valid marker in predicting transplant-free survival in children with BA. This method should be considered an integral part of scoring systems predicting the indication for LTx. Liver Transpl 15:876-882, 2009. (c) 2009 AASLD.

Biliary atresia: recent progress

Extrahepatic biliary atresia (EHBA), an inflammatory sclerosing cholangiopathy, is the leading indication for liver transplantation in children. The cause is still unknown, although possible infectious, genetic, and immunologic etiologies have received much recent focus. These theories are often dependent on each other for secondary or coexisting mechanisms. Concern for EHBA is raised by a cholestatic infant, but the differential diagnosis is large and the path to diagnosis remains varied. Current treatment is surgical with an overall survival rate of approximately 90%. The goals of this article are to review the important clinical aspects of EHBA and to highlight some of the more recent scientific and clinical developments contributing to our understanding of this condition.

Prognostic value of portal pressure at the time of Kasai operation in patients with biliary atresia

AIM

To examine the prognostic value of portal pressure at the time of Kasai operation in patients with biliary atresia (BA).

PATIENTS AND METHODS

All 127 patients with BA, born between 1991 and 1996, who underwent a Kasai operation in Bicêtre Hospital were studied. Intraoperatively, the umbilical vein was catheterised and a portal pressure index (PPI), defined by the height of the physiologic saline column above the liver surface level, was measured. Overall patient survival, survival with native liver (SNL) and, in patients living with their native liver, survival without significant portal hypertension (SwsPHT) were calculated by Kaplan-Meier method and compared by univariate and multivariate analyses.

RESULTS

Measurement of PPI was successful in 113/127 patients (89%) without complication. Median PPI was 15 cm (range, 5-35). Portal pressure index was positively correlated with age at surgery and histological severity of liver fibrosis. Ten-year overall patient survival was 78.2%; 10-year SNL was 35.7%. In patients living with their native liver, 5- and 10-year SwsPHT were 65.3% and 43.6%, respectively. Portal pressure index >15 cm, complete extrahepatic BA and polysplenia were independently associated with a worse SNL. Portal pressure index >15 cm and the absence of postoperative normalisation of bilirubin were independently associated with a worse SwsPHT.

CONCLUSION

Biliary atresia patients with elevated portal pressure at the time of Kasai operation have lower chances of success of this procedure and a higher risk of developing portal hypertension, even if bilirubin levels normalise after the operation. Measurement of PPI was simple and safe and better predicted the postoperative outcome than did the histological scores of liver fibrosis.

Biliary atresia

Biliary atresia (BA) is a rare disease characterised by a biliary obstruction of unknown origin that presents in the neonatal period. It is the most frequent surgical cause of cholestatic jaundice in this age group. BA occurs in approximately 1/18,000 live births in Western Europe. In the world, the reported incidence varies from 5/100,000 to 32/100,000 live births, and is highest in Asia and the Pacific region. Females are affected slightly more often than males. The common histopathological picture is one of inflammatory damage to the intra- and extrahepatic bile ducts with sclerosis and narrowing or even obliteration of the biliary tree. Untreated, this condition leads to cirrhosis and death within the first years of life. BA is not known to be a hereditary condition. No primary medical treatment is relevant for the management of BA. Once BA suspected, surgical intervention (Kasai portoenterostomy) should be performed as soon as possible as operations performed early in life is more likely to be successful. Liver transplantation may be needed later if the Kasai operation fails to restore the biliary flow or if cirrhotic complications occur. At present, approximately 90% of BA patients survive and the majority have normal quality of life.

Management of patients with biliary atresia in France: results of a decentralized policy 1986-2002

This study analyzed the results of the decentralized management of biliary atresia (BA) in France, where an improved collaboration between centers has been promoted since 1997. Results were compared to those obtained in England and Wales, where BA patients have been centralized in three designated centers since 1999. According to their birth dates, BA patients were divided into two cohorts: cohort A, with patients born between 1986 and 1996, had 472 patients; and cohort B, with patients born between 1997 and 2002, had 271 patients. Survival rates were calculated according to the Kaplan-Meier method and compared by using the log rank test and the Cox model. Four-year overall BA patient survival was 73.6% (95% CI 69.5%-77.7%) and 87.1% (CI 82.6%-91.6%) in cohorts A and B, respectively (P < .001). Median age at time of the Kasai operation was 61 and 57 days in cohorts A and B, respectively (NS). Four-year survival with native liver after the Kasai operation was 40.1% and 42.7% in cohorts A and B, respectively (NS): 33.9% (cohort A) and 33.4% (cohort B) in the centers with two or fewer caseloads a year, 30.9% (cohort A) and 44.5% (cohort B) in the centers with 3-5 cases/year, 47.8% (cohort A) and 47.7% (cohort B) in the center with more than 20 caseloads a year. In cohorts A and B, 74 (15.7%) and 19 (7%) patients, respectively, died without liver transplantation (LT). Four-year survival after LT was 75.1% and 88.8% in cohorts A and B, respectively (P = .006). In conclusion, BA patients currently have the same chance of survival in France as in England and Wales. The early success rate of the Kasai operation remains inferior in the centers with limited caseloads in France, leading to a greater need for LTs in infancy and early childhood.