Hepatic graft-versus-host disease: what we know, when to biopsy, and how to diagnose

Graft-versus-host disease (GVHD) is one of the serious complications that may develop after hematopoietic cell transplantation (HCT), for hematologic malignancies, solid organ transplantation, and other hematologic disorders. GVHD develops due to T lymphocytes present in the graft attacking the host antigens, which results in tissue damage. A significant number of HCT patients develop acute or chronic GVHD, which may affect multiple organs including the liver. The diagnosis of hepatic GVHD (hGVHD) is challenging as many other conditions in HCT patients may lead to liver dysfunction. Particularly challenging among the various conditions that give rise to liver dysfunction is differentiating sinusoidal obstruction syndrome and drug-induced liver injury (DILI) from hGVHD on clinical grounds and laboratory tests. Despite the minimal risks involved in performing a liver biopsy, the information gleaned from the histopathologic changes may help in the management of these very complex patients. There is a spectrum of histologic features found in hGVHD, and most involve histopathologic changes affecting the interlobular bile ducts. These include nuclear and cytoplasmic abnormalities including dysmorphic bile ducts, apoptosis, and cholangiocyte necrosis, among others. The hepatitic form of hGVHD typically shows severe acute hepatitis. With chronic hGVHD, there is progressive bile duct loss and eventually fibrosis. Accurate diagnosis of hGVHD is paramount so that timely treatment and management can be initiated. Techniques to prevent and lower the risk of GVHD from developing have recently evolved. If a diagnosis of acute GVHD is made, the first-line of treatment is steroids. Recurrence is common and steroid resistance or dependency is not unusual in this setting. Second-line therapies differ among institutions and have not been uniformly established. The development of GVHD, particularly hGVHD, is associated with increased morbidity and mortality.

Subtype, Frequency, and Associated Background Histology in Males Diagnosed with Hepatocellular Adenomas: A Single Institution Study

Introduction/Objective

Hepatocellular adenomas (HCAs) are rare, benign hepatic neoplasms arising from noncirrhotic livers, most commonly diagnosed in reproductive-age women using oral contraception with female:male ratio of 10:1. These tumors are also associated with anabolic steroid use, obesity, and diabetes. HCA subtypes and their incidence in the general population are as follows: inflammatory (HCA-I) accounting for approximately 50% of cases, HNF1A- inactivated (HCA-H) in 35-40%, β-catenin-activated (HCA-B) in 10-15%, and unclassified HCA in <5-10%. We aimed to determine HCA subtype frequency in male-only cases and their associated background liver histologies.

Methods/Case Report

We performed a retrospective review of all HCAs diagnosed in males from 2000–June 2022 at Mount Sinai Hospital using keywords “hepatocellular adenomas” and “hepatic adenomas;” a total of 54 cases fulfilled the criteria. Liver biopsies and resection specimens were included; duplicate cases were eliminated, and only those cases with a definitive diagnosis of HCA were included.

Results (if a Case Study enter NA)

There were 31 patients (age range 17-73 years) included with a total number of 41 HCAs (17 from resections and 14 from biopsies). HCA-I comprised 23/31 cases (74%), HCA-H and HCA-B each encompassed 2/31 cases (6%, respectively), one HCA-I had coexistent β-catenin mutation (3%, 1/31), and one unclassified HCA had mixed HCA-I and HCA-H features (3%, 1/31). Twelve cases were diagnosed as HCA without further subtype specification (NOS) (38%). Background liver histology was available in 24 cases. Fatty liver disease (steatosis and steatohepatitis) was found in five cases, of which four were classified as HCA-I. Of seven hepatocellular carcinomas diagnosed, four arose from NOS HCAs with either unremarkable or steatohepatitis backgrounds. Three of five HCA-I showed background nonspecific chronic hepatitis while two had glycogen storage disease. The remaining ten cases had unremarkable liver backgrounds and were found involving all HCA subtypes.

Conclusion

In this cohort of male-only patients, HCA-I was the most common subtype, the frequency of which is significantly higher than is reported in the general population. Only 6% of cases were HNF1A-inactivated and β- catenin-activated, far less than the reported incidence of 35-40% and 10-15%, respectively. Additionally, our findings show that the majority of HCAs had an unremarkable liver background. Further studies are necessary to determine the neoplastic drivers among male patients that develop hepatocellular adenomas.

COVID Cholangiopathy Can Occur Despite Mild COVID

Introduction/Objective

Post-COVID-19 cholangiopathy is a novel entity first noted in patients recovering from critical COVID-19 infection. Since its initial description in May 2021, all cases reported to date have been in patients with a history of critical COVID-19, defined as requiring ICU admission, the development of respiratory or circulatory failure requiring intubation or ECMO, or vasopressor support. Here we report three cases of post-COVID-19 cholangiopathy arising in patients who recovered from non-severe COVID-19.

Methods/Case Report

Six cases of COVID-19-related cholangiopathy were identified by retrospective review, three of which involved patients who verifiably did not develop critical COVID-19. Histology slides for each case were reviewed and all showed features of secondary sclerosing cholangitis. Patient 1 is a 41yo female who developed COVID-19 after liver transplant (LT). Despite administration of monoclonal antibodies, she required re-transplantation 6 weeks later. Explant histology showed bile infarcts, severe hepatocytic and canalicular cholestasis, ductular reaction, organizing portal vein thrombi, and necrotic bile ducts accompanied by bile lakes. Patient 2 is a 47yo male with alcoholic cirrhosis who was diagnosed with COVID-19 at the time of LT workup, and underwent LT 90 days later. In addition to alcohol-related cirrhosis, explant histology showed dilated bile ducts with periductal fibrosis, as well as severe ductular reaction with proliferating ductules containing thick, inspissated bile. Patient 3 is a 54yo male with history of LT for PSC who developed mild COVID-19 five years after LT. Allograft function subsequently worsened and biopsy 6 months later showed bile duct damage and loss of ~35% of bile ducts; repeat biopsy 14 months after his COVID diagnosis showed periportal fibrosis with edema, ductular reaction, marked hepatocellular and canalicular cholestasis, and ductopenia with loss of 60% bile ducts. Average time between COVID-19 diagnosis and onset of COVID-related cholangiopathy was 3 months (range: 6 weeks-6 months). These patients were also all immunocompromised with two due to prior LT and one being cirrhotic.

Results (if a Case Study enter NA)

NA.

Conclusion

Although previously reported only in patients with severe COVID-19, the cases described represent the first evidence that cholangiopathy, manifested by sclerosing cholangitis, can arise even in patients who were not critically ill, although this may require an immunocompromised state to develop.

The Quantification and Significance of Extramedullary Hematopoiesis Seen on Liver Biopsy Specimens

OBJECTIVES

Extramedullary hematopoiesis (EMH) may occur in the liver and is often considered pathologic in adults. Many hematologic and nonhematologic disorders are associated with the development of EMH. However, it is unclear whether the presence of EMH is always pathologic. At present, no formal grading system for EMH in the liver exists.

METHODS

We reviewed 42 liver biopsy specimens with EMH and developed a novel grading system to quantify the degree of EMH from 1 to 3 based on the number of EMH foci in 10 high-power fields.

RESULTS

Most patients had nonhematologic conditions (n = 25). Seventeen patients had a hematologic condition, most frequently a myeloproliferative neoplasm (n = 9). Patients with an underlying hematologic condition had a significantly higher EMH grade compared with those without a hematologic condition (P < .0001). All patients with grade 3 EMH had an underlying hematologic diagnosis, and most (86%) patients with grade 1 EMH had a nonhematologic disorder.

CONCLUSIONS

Our data suggest that EMH grading in the liver is feasible and can identify patients who may have an underlying hematologic condition, which can guide further diagnostic workup.

The use of transient elastography in identifying sub-clinical chronic ductopenic rejection in adult liver transplant recipients: A case series

BACKGROUND

Transient elastography has become a standard tool for the accurate non-invasive assessment of liver stiffness and fat content. Liver transplant recipients can develop allograft fibrosis during long-term follow-up despite normal or mildly abnormal liver chemistries. Tapering of immunosuppression in long-term liver transplant survivors is performed relying solely on liver chemistries. It is important to know if underlying liver histology would be abnormal or if rejection was present as this would alter the desire to decrease stable maintenance doses of immunosuppression.

METHODS

We present our experience of five liver transplant recipients who had transient elastography performed prior to consideration of weaning of their immunosuppression.

RESULTS

All five patients showed signs of elevated liver stiffness on transient elastography in the setting of normal to slightly abnormal liver tests with very stable immunosuppressant doses. This prompted the performance of liver biopsies which demonstrated immune-mediated liver injury and thus negated the immunosuppression withdrawal.

CONCLUSION

Transient elastography has utility as a non-invasive method to evaluate allograft health in long-term liver transplant survivors and can be useful in the decision-making process for immunosuppression weaning.

Assessment of HCC response to Yttrium-90 radioembolization with gadoxetate disodium MRI: correlation with histopathology

BACKGROUND AND AIMS

Transarterial ⁹⁰Y radioembolization (TARE) is increasingly being used for hepatocellular carcinoma (HCC) treatment. However, tumor response assessment after TARE may be challenging. We aimed to assess the diagnostic performance of gadoxetate disodium MRI for predicting complete pathologic necrosis (CPN) of HCC treated with TARE, using histopathology as the reference standard.

METHODS

This retrospective study included 48 patients (M/F: 36/12, mean age: 62 years) with HCC treated by TARE followed by surgery with gadoxetate disodium MRI within 90 days of surgery. Two radiologists evaluated tumor response using RECIST1.1, mRECIST, EASL, and LI-RADS-TR criteria and evaluated the percentage of necrosis on subtraction during late arterial, portal venous, and hepatobiliary phases (AP/PVP/HBP). Statistical analysis included inter-reader agreement, correlation between radiologic and pathologic percentage of necrosis, and prediction of CPN using logistic regression and ROC analyses.

RESULTS

Histopathology demonstrated 71 HCCs (2.8 ± 1.7 cm, range: 0.5-7.5 cm) including 42 with CPN, 22 with partial necrosis, and 7 without necrosis. EASL and percentage of tumor necrosis on subtraction at the AP/PVP were independent predictors of CPN (p = 0.02-0.03). Percentage of necrosis, mRECIST, EASL, and LI-RADS-TR had fair to good performance for diagnosing CPN (AUCs: 0.78 - 0.83), with a significant difference between subtraction and LI-RADS-TR for reader 2, and in specificity between subtraction and other criteria for both readers (p-range: 0.01-0.04). Radiologic percentage of necrosis was significantly correlated to histopathologic degree of tumor necrosis (r = 0.66 - 0.8, p < 0.001).

CONCLUSIONS

Percentage of tumor necrosis on subtraction and EASL criteria were significant independent predictors of CPN in HCC treated with TARE. Image subtraction should be considered for assessing HCC response to TARE when using MRI.

KEY POINTS

• Percentage of tumor necrosis on image subtraction and EASL criteria are significant independent predictors of complete pathologic necrosis in hepatocellular carcinoma treated with⁹⁰Y radioembolization. • Subtraction, mRECIST, EASL, and LI-RADS-TR have fair to good performance for diagnosing complete pathologic necrosis in hepatocellular carcinoma treated with⁹⁰Y radioembolization.

Impaired central tolerance induces changes in the gut microbiota that exacerbate autoimmune hepatitis

Medullary thymic epithelial cells (mTECs) induce T cell tolerance in the thymus through the elimination of self-reactive thymocytes. Commensal bacteria are also critical for shaping T cell responses in the gut and distal organs. We previously showed that mice depleted of mTECs (Traf6ΔTEC) generated autoreactive T cells and developed autoimmune hepatitis (AIH). In this report, we found that Toll-like receptor (TLR)-mediated microbial sensing on liver hematopoietic cells and the gut microbiota contributed to AIH development in Traf6ΔTEC mice. While adoptive transfer of thymic Traf6ΔTEC T cells in immune-deficient mice was sufficient for AIH development, colonization of germ-free mice with Traf6ΔTEC microbiota failed to induce AIH, suggesting that the gut microbiota contributes to but is not sufficient for AIH development. Microbiota-mediated exacerbation of AIH associated with increased numbers of hepatic Foxp3+ T cells and their increase was proportional to the degree of inflammation. The contribution of the gut microbiota to AIH development associated with an altered microbial signature whose composition was influenced by the qualitative nature of the thymic T cell compartment. These results suggest that aberrant selection of T cells in the thymus can induce changes in the gut microbiota that lead to exacerbation of organ-specific autoimmunity and AIH. Our results add to our understanding of the mechanisms of AIH development and create a platform towards developing novel therapeutic approaches for treating this disease.

Recurrent Liver Allograft Injury in Patients With Donor-Derived Malignancy Treated With Immunosuppression Cessation and Retransplantation

OBJECTIVES

Donor-derived malignancy of the liver allograft is a rare but serious condition in the setting of necessary immunosuppression. Retransplantation after abrupt immunosuppression cessation has been performed with durable cancer-free survival.

METHODS

We present 2 cases of patients with donor-derived malignancy who were treated with complete immunosuppression cessation, which induced rapidly progressive liver allograft rejection and failure, with a need for subsequent retransplantation. We reviewed all serial liver biopsies and explants from both patients and performed C4d immunostaining.

RESULTS

Initial explants of both patients showed severe allograft rejection, with unusual features of sinusoidal obstruction syndrome and C4d positivity. Malignant tumors in the explants were necrotic, related to rejection of donor-derived cancer cells and tissue. Follow-up of both patients has shown long-term cancer-free survival but issues with recurrent allograft failure requiring a third transplant. The reasons for retransplantation in both cases were related to allograft failure from antibody-mediated rejection.

CONCLUSIONS

Clinicians should be aware of a potentially increased risk of rejection and recurrent allograft failure when strategizing treatment of donor-derived malignancy with immunosuppression cessation and retransplantation.

N-Glycosylation Patterns Correlate with Hepatocellular Carcinoma Genetic Subtypes

Hepatocellular carcinoma (HCC) is the second leading cause of cancer deaths globally, and the incidence rate in the United States is increasing. Studies have identified inter- and intratumor heterogeneity as histologic and/or molecular subtypes/variants associated with response to certain molecular targeted therapies. Spatial HCC tissue profiling of N-linked glycosylation by matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS) may serve as a new method to evaluate the tumor heterogeneity. Previous work has identified significant changes in the N-linked glycosylation of HCC tumors but has not accounted for the heterogeneous genetic and molecular nature of HCC. To determine the correlation between HCC-specific N-glycosylation changes and genetic/molecular tumor features, we profiled HCC tissue samples with MALDI-IMS and correlated the spatial N-glycosylation with a widely used HCC molecular classification (Hoshida subtypes). MALDI-IMS data displayed trends that could approximately distinguish between subtypes, with subtype 1 demonstrating significantly dysregulated N-glycosylation versus adjacent nontumor tissue. Although there were no individual N-glycan structures that could identify specific subtypes, trends emerged regarding the correlation of branched glycan expression to HCC as a whole and fucosylated glycan expression to subtype 1 tumors specifically. IMPLICATIONS: Correlating N-glycosylation to specific subtypes offers the specific detection of subtypes of HCC, which could both enhance early HCC sensitivity and guide targeted clinical therapies.

Antibody-mediated rejection of the liver allograft: An update and a clinico-pathological perspective

Antibody-mediated rejection after liver transplantation is an under-recognised cause of allograft injury. While definitions of acute and chronic antibody-mediated rejection have increased clinical awareness, timely identification and management of antibody-mediated rejection remain difficult because of complexities in diagnosis and histopathology, lack of treatment protocols, and unclear long-term outcomes. While recent cohort studies assessing the importance of donor-specific antibodies have aided in its diagnosis, literature on the treatment of antibody-mediated rejection in liver transplantation remain limited to case reports and small series. Further increasing the awareness and timely recognition of antibody-mediated rejection post-liver transplantation is crucial in order to stimulate future research and the development of protocols for its diagnosis and treatment. This review will summarise recent advances in the clinical diagnosis and treatment of antibody-mediated rejection in liver transplantation, as well as some of the histopathologic features (on liver biopsy tissue) of acute and chronic antibody-mediated rejection.

Hemophagocytic lymphohistiocytosis occurring after liver transplantation: A case series and review of the literature

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disease characterized by excessive inflammation and tissue destruction due to a dysregulated immune response. Its secondary form is most commonly triggered by viral infection or malignancy. There have previously been 11 cases of acquired HLH described following liver transplantation in adult transplant recipients, most occurring within the first year following transplantation. Herein, we describe two cases of HLH in liver transplant recipients that both occurred remotely following transplantation. In the first case, HLH was thought to be triggered by the development of a post-transplant lymphoproliferative disorder in a patient who was initially diagnosed with recurrent autoimmune hepatitis. In the second, it was thought to be triggered by a newly acquired human herpesvirus-8 infection. In both cases, the syndrome was not recognized until treatment for the initial putative diagnoses was unsuccessful. Despite treatment, both patients unfortunately died from multiorgan failure. HLH in the post-liver transplant setting is likely under-recognized and has a high mortality; early diagnosis and intervention may lead to improved outcomes.

The role of endoscopy in the small intestinal transplant recipient: A review

Intestinal transplantation (ITx) is the treatment of choice for patients with intestinal failure who have developed life-threatening complications related to long-term parenteral nutrition. Patients may also undergo ITx as part of a combined liver-intestine or multivisceral transplant for a variety of indications, most commonly intestinal failure-associated liver disease or porto-mesenteric thrombosis. Endoscopy plays a critical role in the posttransplant management of these patients, most commonly in the diagnosis and management of rejection, which occurs in up to 30-40% of patients within the first-year posttransplant. With a lack of noninvasive biomarkers to identify the presence of rejection, endoscopy and biopsy remain the gold standard for its diagnosis. Endoscopic evaluation of the graft is also important in the identification of other complications post-ITx, including posttransplant lymphoproliferative disorder, graft-versus-host disease, and enteric infections. Each patient's posttransplant anatomy may be slightly different, making endoscopy sometimes technically challenging and necessitating clear and frequent communication with the surgical team in order to help identify the highest yield approach. Herein, we review the most common pathologies found endoscopically in the post-ITx patient and describe some of the unique challenges the endoscopist faces when evaluating these complex patients.

Evaluation of the fibrosis-4 index for detection of advanced fibrosis among individuals at risk for intestinal failure-associated liver disease

BACKGROUND

Intestinal failure-associated liver disease (IFALD) refers to the spectrum of liver injury secondary to IF and parenteral nutrition use. Our aim was to evaluate the use of noninvasive indices of liver fibrosis to detect advanced fibrosis among individuals at risk for IFALD.

METHODS

We performed a secondary analysis of a retrospective study, including all liver biopsies performed on individuals undergoing intestinal transplantation (ITx) between January 2000 and May 2014. To determine the clinical utility of detecting advanced fibrosis, receiver operating characteristic curves were developed. Comparison between the area under the curves was performed by DeLong test.

RESULTS

Fifty-three patients had a liver biopsy performed at the time of ITx; 13 of 53 (24.5%) patients had advanced fibrosis. The fibrosis-4 (FIB-4) index positively correlated to the stage of fibrosis on liver biopsy (r = 0.426, P = .002). When compared against the FIB-4 index, the aspartate aminotransferase to platelet ratio index had a significantly decreased ability to correctly identify the presence of advanced fibrosis (P = .019). When determining the cutoff value with 90% specificity for the detection of advanced fibrosis, a FIB-4 index of ≥4.4 had a sensitivity of 0.462 and a positive predictive value of 0.6.

CONCLUSION

In this retrospective cohort study, we found a positive correlation between the FIB-4 index and the liver fibrosis stage as characterized by the Brunt classification. This evaluation of the FIB-4 index against liver biopsies supports the use of the FIB-4 index in the detection of liver fibrosis in IF.

Consensus report from the 9th International Forum for Liver Magnetic Resonance Imaging: applications of gadoxetic acid-enhanced imaging

Objectives

The 9th International Forum for Liver Magnetic Resonance Imaging (MRI) was held in Singapore in September 2019, bringing together radiologists and allied specialists to discuss the latest developments in and formulate consensus statements for liver MRI, including the applications of gadoxetic acid–enhanced imaging.

Methods

As at previous Liver Forums, the meeting was held over 2 days. Presentations by the faculty on days 1 and 2 and breakout group discussions on day 1 were followed by delegate voting on consensus statements presented on day 2. Presentations and discussions centered on two main meeting themes relating to the use of gadoxetic acid–enhanced MRI in primary liver cancer and metastatic liver disease.

Results and conclusions

Gadoxetic acid–enhanced MRI offers the ability to monitor response to systemic therapy and to assist in pre-surgical/pre-interventional planning in liver metastases. In hepatocellular carcinoma, gadoxetic acid–enhanced MRI provides precise staging information for accurate treatment decision-making and follow-up post therapy. Gadoxetic acid–enhanced MRI also has potential, currently investigational, indications for the functional assessment of the liver and the biliary system. Additional voting sessions at the Liver Forum debated the role of multidisciplinary care in the management of patients with liver disease, evidence to support the use of abbreviated imaging protocols, and the importance of standardizing nomenclature in international guidelines in order to increase the sharing of scientific data and improve the communication between centers.

Key Points

• Gadoxetic acid–enhanced MRI is the preferred imaging method for pre-surgical or pre-interventional planning for liver metastases after systemic therapy.

• Gadoxetic acid–enhanced MRI provides accurate staging of HCC before and after treatment with locoregional/biologic therapies.

• Abbreviated protocols for gadoxetic acid–enhanced MRI offer potential time and cost savings, but more evidence is necessary. The use of gadoxetic acid–enhanced MRI for the assessment of liver and biliary function is under active investigation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-020-07637-4.

A subset of liver resident natural killer cells is expanded in hepatitis C-infected patients with better liver function

Viral hepatitis leads to immune-mediated liver injury. The rate of disease progression varies between individuals. We aimed to phenotype immune cells associated with preservation of normal liver function during hepatitis C virus (HCV) infection. Clinical data and specimens were obtained from 19 HCV-infected patients undergoing liver transplantation. Liver and peripheral blood mononuclear cells were isolated and eight subsets of innate immune cells were delineated by multiparameter flow cytometry. Cytokine assays and microarrays were performed. Intrahepatic CD56^Bright/CD16^- natural killer (NK) cells comprised the only subset correlating with better liver function, i.e., lower bilirubin (p = 0.0002) and lower model for end stage of liver disease scores (p = 0.03). The signature of liver NK cells from HCV-infected patients included genes expressed by NK cells in normal liver and by decidual NK cells. Portal vein blood had a higher concentration of interleukin (IL)-10 than peripheral blood (p = 0.03). LMCs were less responsive to toll-like receptor (TLR) stimulation than PBMCs, with fewer pro-inflammatory gene-expression pathways up-regulated after in vitro exposure to lipopolysaccharide and a TLR-7/8 agonist. Hepatic CD56^Bright/CD16^- NK cells may be critical for maintaining liver homeostasis. Portal vein IL-10 may prime inhibitory pathways, attenuating TLR signaling and reducing responsiveness to pro-inflammatory stimuli.

Modeling dysbiosis of human NASH in mice: Loss of gut microbiome diversity and overgrowth of Erysipelotrichales

Background & aim

Non-alcoholic steatohepatitis (NASH) is a severe form of non-alcoholic fatty liver disease (NAFLD) that is responsible for a growing fraction of cirrhosis and liver cancer cases worldwide. Changes in the gut microbiome have been implicated in NASH pathogenesis, but the lack of suitable murine models has been a barrier to progress. We have therefore characterized the microbiome in a well-validated murine NASH model to establish its value in modeling human disease.

Methods

The composition of intestinal microbiota was monitored in mice on a 12- or 24-week NASH protocol consisting of high fat, high sugar Western Diet (WD) plus once weekly i.p injection of low-dose CCl₄. Additional mice were subjected to WD-only or CCl₄-only conditions to assess the independent effect of these variables on the microbiome.

Results

There was substantial remodeling of the intestinal microbiome in NASH mice, characterized by declines in both species diversity and bacterial abundance. Based on changes to beta diversity, microbiota from NASH mice clustered separately from controls in principal coordinate analyses. A comparison between WD-only and CCl₄-only controls with the NASH model identified WD as the primary driver of early changes to the microbiome, resulting in loss of diversity within the 1^st week. A NASH signature emerged progressively at weeks 6 and 12, including, most notably, a reproducible bloom of the Firmicute order Erysipelotrichales.

Conclusions

We have established a valuable model to study the role of gut microbes in NASH, enabling us to identify a new NASH gut microbiome signature.

Prenatal Exposure to Gutkha, a Globally Relevant Smokeless Tobacco Product, Induces Hepatic Changes in Adult Mice

Maternal exposures during pregnancy affect the onset and progression of adult diseases in the offspring. A prior mouse study indicated that maternal tobacco smoke exposure affects hepatic fibrosis in adult offspring. Gutkha, a broadly used smokeless tobacco (ST) product, is widely used by pregnant woman in many countries. The objective of this murine study was to evaluate whether oral maternal exposure to gutkha during pregnancy alters non-alcoholic fatty liver disease (NAFLD) in adult offspring: risk factors for the progression of NAFLD to cirrhosis in adults remain elusive. Buccal cavity 'painting' of pregnant mice with gutkha began on gestational days (GD) 2-4 and continued until parturition. Beginning at 12 weeks of age, a subset of offspring were transitioned to a high-fat diet (HFD). Results demonstrated that prenatal exposure to gutkha followed by an HFD in adulthood significantly increased the histologic evidence of fatty liver disease only in adult male offspring. Changes in hepatic fibrosis-related cytokines (interleukin (IL)-1b and IL-6) and in hepatic collagen mRNA expression were observed when comparing adult male offspring exposed to gutkha in utero to those not exposed. These findings indicate that maternal use of gutkha during pregnancy affects NAFLD in adult offspring in a sex-dependent manner.

Interobserver study on histologic features of idiopathic non-cirrhotic portal hypertension

Background

Histologic features of idiopathic non-cirrhotic portal hypertension (INCPH) may overlap with those without INCPH. Recently, these features have been recognized as part of the larger spectrum of porto-sinusoidal vascular disease (PSVD). We assessed interobserver agreement on histologic features that are commonly associated with INCPH and studied whether a provision of relevant clinical history improves interobserver agreement.

Methods

The examined histologic features include lobular (such as anisocytosis, nodular regeneration, sinusoidal dilatation, increased parenchymal draining veins, and incomplete fibrous septa) and portal tract changes (such as paraportal shunting vessel(s), portal tract remnant, increased number of portal vessels, and obliterative portal venopathy). Thirty-four archived liver samples from patients with (group A) and without (group B) INCPH were retrieved. A total of 90 representative images of lobules (L) and portal tracts (P) were distributed among 9 liver pathologists blinded to true clinical history. Each pathologist answered multiple choice questions based on the absence (Q1) or presence (Q2) of clinical history of portal hypertension. Fleiss’ kappa coefficient analysis (unweighted) was performed to assess interobserver agreement on normal versus abnormal diagnosis, in L and P, based on Q1 and Q2.

Results

The kappa values regarding normal versus abnormal diagnosis were 0.24, 0.24, 0.18 and 0.18 for L-Q1, L-Q2, P-Q1, and P-Q2, respectively. With true clinical history provided, the kappa values were L- 0.32, P-0.17 for group A and L-0.12, P-0.14 for group B. Four pathologists changed their assessments based on the provided history. Interobserver agreement on the interpretation of L and P as normal versus abnormal was slight to fair regardless of provision of clinical history.

Conclusions

Our findings indicate that the histologic features of INCPH/PSVD are not limited to patients with portal hypertension and are subject to significant interobserver variation.

Supplementary information

The online version contains supplementary material available at 10.1186/s13000-020-01049-0.

Findings of Hepatic Severe Acute Respiratory Syndrome Coronavirus-2 Infection

BACKGROUND & AIMS

Liver injury due to coronavirus disease 2019 (COVID-19) is being increasingly recognized. Abnormal liver chemistry tests of varying severities occur in a majority of patients. However, there is a dearth of accompanying liver histologic studies in these patients.

METHODS

The current report details the clinical courses of 2 patients having severe COVID-19 hepatitis. Liver biopsies were analyzed under light microscopy, portions of liver tissue were hybridized with a target probe to the severe acute respiratory syndrome coronavirus-2 S gene, and small sections from formalin-fixed paraffin-embedded liver tissue were processed for electron microscopy.

RESULTS

The liver histology of both cases showed a mixed inflammatory infiltrate with prominent bile duct damage, endotheliitis, and many apoptotic bodies. In situ hybridization and electron microscopy suggest the intrahepatic presence of severe acute respiratory syndrome coronavirus-2, the findings of which may indicate the possibility of direct cell injury.

CONCLUSIONS

On the basis of the abundant apoptosis and severe cholangiocyte injury, these histopathologic changes suggest a direct cytopathic injury. Furthermore, some of the histopathologic changes may resemble acute cellular rejection occurring after liver transplantation. These 2 cases demonstrate that severe COVID-19 hepatitis can occur even in the absence of significant involvement of other organs.

Aberrant von Willebrand factor expression of sinusoidal endothelial cells and quiescence of hepatic stellate cells in nodular regenerative hyperplasia and obliterative portal venopathy

AIMS

Nodular regenerative hyperplasia (NRH) and obliterative portal venopathy (OPV), entities that comprise idiopathic non-cirrhotic portal hypertension (INCPH), are under-recognised diseases of uncertain aetiology and the diagnosis can be easily missed on liver biopsy. The expression of CD34 and von Willebrand factor (vWF) in liver sinusoidal endothelial cells (LSEC) and alpha-smooth muscle actin (ASMA) in hepatic stellate cells (HSCs) is unknown in NRH and OPV. We sought to investigate the pathogenesis and potential immunomarkers that might aid in making the diagnosis of NRH and OPV.

METHODS AND RESULTS

Immunohistochemical (IHC) staining for CD34, vWF and ASMA was performed in clinically and histologically well-characterised NRH (n = 15) and OPV (n = 47) liver specimens. Among the 47 OPV cases, 37 (78.7%) had concurrent features of NRH. CD34 positive staining was mainly confined to small vessels in the portal tracts and LSECs in periportal areas, a finding similar to that in non-NRH/OPV livers. However, expression of vWF in LSECs was positive in the compressed sinusoids of NRH and in a patchy or geographic pattern, particularly prominent in the perivenular areas and dilated sinusoids of OPV cases. HSCs were negative for ASMA in all NRH and OPV cases.

CONCLUSION

Our findings indicate that NRH may be a subtle but common concurrent morphological feature in OPV. The aberrant expression of vWF in LSECs suggests that endothelial injury may play a role in the pathogenesis, which may thus aid in the recognition and diagnosis of NRH and OPV, particularly when confronted with otherwise apparent normal liver histology on needle biopsy.

Mannose Phosphate Isomerase and Mannose Regulate Hepatic Stellate Cell Activation and Fibrosis in Zebrafish and Humans

The growing burden of liver fibrosis and lack of effective antifibrotic therapies highlight the need for identification of pathways and complementary model systems of hepatic fibrosis. A rare, monogenic disorder in which children with mutations in mannose phosphate isomerase (MPI) develop liver fibrosis led us to explore the function of MPI and mannose metabolism in liver development and adult liver diseases. Herein, analyses of transcriptomic data from three human liver cohorts demonstrate that MPI gene expression is down-regulated proportionate to fibrosis in chronic liver diseases, including nonalcoholic fatty liver disease and hepatitis B virus. Depletion of MPI in zebrafish liver in vivo and in human hepatic stellate cell (HSC) lines in culture activates fibrotic responses, indicating that loss of MPI promotes HSC activation. We further demonstrate that mannose supplementation can attenuate HSC activation, leading to reduced fibrogenic activation in zebrafish, culture-activated HSCs, and in ethanol-activated HSCs. Conclusion: These data indicate the prospect that modulation of mannose metabolism pathways could reduce HSC activation and improve hepatic fibrosis.

Diagnosis of Liver Neoplasms by Computational and Statistical Image Analysis

Background

Distinguishing well-differentiated hepatocellular carcinoma (WD-HCC), hepatocellular adenoma (HA) and non-neoplastic liver tissue (NNLT) solely on morphology is often challenging. The purpose of this study was to evaluate the use of computational image analysis to distinguish WD-HCC, HA and NNLT.

Methods

Seventy-seven cases comprising of WD-HCC (n = 26), HA (n = 23) and NNLT (n = 28) were retrieved and reviewed. A total of 485 hematoxylin and eosin (H&E) photomicrographs (× 400, 0.09 µm²) of WD-HCC (n = 183), HA (n = 173), NNLT (n = 129) and nine whole-slide scans (three of each diagnosis) were obtained, color deconvoluted and digitally transformed. Quantitative data including nuclear density, nuclear sphericity, nuclear perimeter, and nuclear eccentricity from each image were acquired. The data were analyzed by one-way analysis of variance (ANOVA) with Tukey post hoc test, followed by unsupervised and supervised (Chi-square automatic interaction detection (CHAID)) cluster analysis.

Results

Unsupervised cluster analysis identified three well defined clusters of WD-HCC, HA and NNLT. Employing the four most discriminating nuclear features, supervised analysis was performed on a training set of 383 images, and validated on the remaining 102 test images. The analysis identified WD-HCC (sensitivity 100%, specificity 98%), HA (sensitivity 71%, specificity 85%) and NNLT (sensitivity 70%, specificity 86%). An analysis of whole-slide images identified WD-HCC with sensitivity and specificity of 100%.

Conclusions

We have successfully demonstrated that computational image analysis of nuclear features can differentiate WD-HCC from non-malignant liver with high accuracy, and can be used to assist in the histopathological diagnosis of hepatocellular carcinoma.

Resolution of HCV-Autoimmune Hepatitis Overlap Syndrome With Antiviral TreatmentA Paired Liver Biopsy Study

OBJECTIVES

To evaluate histologic changes occurring in patients having chronic hepatitis C and autoimmune hepatitis overlap (HCV-AIH), and who achieved virologic cure using direct-acting antiviral agents (DAA).

METHODS

Characteristics of HCV-AIH patients who underwent paired liver biopsies before and after receiving DAA treatment from 2011 to 2018 were evaluated.

RESULTS

Five HCV-AIH patients (three male; mean age, 60.4 years) underwent paired liver biopsies (average interval, 2.3 years) before and after achieving cure with DAA treatment. All patients showed virologic response, while four showed decreased inflammation, and three cases showed features of fibrosis regression. Immunohistochemical staining demonstrated significant decrease in plasma cell count in three patients (20.6 vs 11.9 plasma cells/high power field; P = .02, t test).

CONCLUSIONS

Histologic improvements in inflammation and fibrosis are noted in most HCV-AIH patients after DAA treatment, suggesting that the autoimmune component of the HCV-AIH overlap syndrome is merely a secondary phenomenon of viral infection.

Recurrent Idiopathic Liver Allograft Failure

OBJECTIVES

Many transplant programs have had patients who develop idiopathic recurrent liver allograft failure, necessitating serial transplants, and are deemed to have refractory or recurrent rejection. The frequency and the etiology of this immunologic dysfunction have not been well characterized.

METHODS

Herein, we illustrate the case of a patient who required three retransplants over a period of 20 years for recurrent liver allograft failure. By extensively compiling the patient's many liver biopsy specimens and explants over time, we demonstrate that antibody-mediated rejection (AMR) was a major contributing factor from the outset. We conducted a review of the Scientific Registry for Transplant Recipients database to estimate the potential frequency of AMR.

RESULTS

As illustrated by this case, AMR has varied histologic findings in the setting of elevated donor-specific antibody titers.

CONCLUSIONS

The cause of recurrent allograft failure in this patient was likely a combination of acute cellular rejection and AMR, manifestations of likely underlying immune dysregulation. Pathologists and transplant physicians should recognize the variable histologic presentations of AMR, which is imperative for its timely intervention. This case demonstrates how difficult the diagnosis of AMR can be to make, highlighting the need for strong clinical suspicion in patients having difficult-to-treat rejection and recurrent allograft failure.

Individual liver plasmacytoid dendritic cells are capable of producing IFNα and multiple additional cytokines during chronic HCV infection

Plasmacytoid dendritic cells (pDCs) are "natural" interferon α (IFNα)-producing cells. Despite their importance to antiviral defense, autoimmunity, and ischemic liver graft injury, because DC subsets are rare and heterogeneous, basic questions about liver pDC function and capacity to make cytokines remain unanswered. Previous investigations failed to consistently detect IFNα mRNA in HCV-infected livers, suggesting that pDCs may be incapable of producing IFNα. We used a combination of molecular, biochemical, cytometric, and high-dimensional techniques to analyze DC frequencies/functions in liver and peripheral blood mononuclear cells (PBMCs) of hepatitis C virus (HCV)-infected patients, to examine correlations between DC function and gene expression of matched whole liver tissue and liver mononuclear cells (LMCs), and to determine if pDCs can produce multiple cytokines. T cells often produce multiple cytokines/chemokines but until recently technical limitations have precluded tests of polyfunctionality in individual pDCs. Mass cytometry (CyTOF) revealed that liver pDCs are the only LMC that produces detectable amounts of IFNα in response TLR-7/8 stimulation. Liver pDCs secreted large quantities of IFNα (~2 million molecules of IFNα/cell/hour) and produced more IFNα than PBMCs after stimulation, p = 0.0001. LMCs secreted >14-fold more IFNα than IFNλ in 4 hours. Liver pDC frequency positively correlated with whole liver expression of "IFNα-response" pathway (R2 = 0.58, p = 0.007) and "monocyte surface" signature (R2 = 0.54, p = 0.01). Mass cytometry revealed that IFNα-producing pDCs were highly polyfunctional; >90% also made 2-4 additional cytokines/chemokines of our test set of 10. Liver BDCA1 DCs, but not BDCA3 DCs, were similarly polyfunctional. pDCs from a healthy liver were also polyfunctional. Our data show that liver pDCs retain the ability to make abundant IFNα during chronic HCV infection and produce many other immune modulators. Polyfunctional liver pDCs are likely to be key drivers of inflammation and immune activation during chronic HCV infection.

HIV infection modulates IL-1β response to LPS stimulation through a TLR4-NLRP3 pathway in human liver macrophages

IL-1β is an important mediator of innate inflammatory responses and has been shown to contribute to liver injury in a number of etiologies. HIV patients have increased necroinflammation and more rapid fibrosis progression in chronic liver injury compared to non-HIV-infected patients. As the resident liver macrophage is critical to the IL-1β response to microbial translocation in chronic liver disease, we aim to examine the impact of HIV-1 and LPS stimulation on the IL-1β response of the resident hepatic macrophages. We isolated primary human liver macrophages from liver resection specimens, treated them with HIV-1_BaL and/or LPS ex vivo, examined the IL-1β response, and then studied underlying mechanisms. Furthermore, we examined IL-1β expression in liver tissues derived from HIV-1 patients compared to those with no underlying liver disease. HIV-1 up-regulated TLR4 and CD14 expression on isolated primary CD68+ human liver macrophages and contributed to the IL-1β response to LPS stimulation as evidenced by TLR4 blocking. Nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) was shown to be involved in the IL-1β response of liver macrophages to HIV-1 infection and NLRP3 blocking experiments in primary CD68+ liver macrophages confirmed the contribution of the NLRP3-caspase 1 inflammatory signaling pathway in the IL-1β response. High in situ IL-1β expression was found in CD68⁺ cells in human liver tissues from HIV-1-infected patients, suggesting a critical role of IL-1β responses in patients infected by HIV. HIV infection sensitizes the IL-1β response of liver macrophages to LPS through up-regulation of CD14 and TLR4 expression and downstream activation of the NLRP3-caspase 1 pathway. These findings have implications for enhanced immune activation in HIV⁺ patients and mechanisms for rapid fibrosis progression in patients with chronic liver injury.

Autophagy is a gatekeeper of hepatic differentiation and carcinogenesis by controlling the degradation of Yap

Activation of the Hippo pathway effector Yap underlies many liver cancers, however no germline or somatic mutations have been identified. Autophagy maintains essential metabolic functions of the liver, and autophagy-deficient murine models develop benign adenomas and hepatomegaly, which have been attributed to activation of the p62/Sqstm1-Nrf2 axis. Here, we show that Yap is an autophagy substrate and mediator of tissue remodeling and hepatocarcinogenesis independent of the p62/Sqstm1-Nrf2 axis. Hepatocyte-specific deletion of Atg7 promotes liver size, fibrosis, progenitor cell expansion, and hepatocarcinogenesis, which is rescued by concurrent deletion of Yap. Our results shed new light on mechanisms of Yap degradation and the sequence of events that follow disruption of autophagy, which is impaired in chronic liver disease.

Increased levels of the Yap oncoprotein stimulate liver growth and promote hepatocarcinogenesis. Here the authors show that hepatocyte-specific loss of Atg7 in mice leads to decreased autophagic degradation of Yap and liver overgrowth, and further establish this association in human liver cancer tissues.

A simple diet- and chemical-induced murine NASH model with rapid progression of steatohepatitis, fibrosis and liver cancer

BACKGROUND AND AIMS

Although the majority of patients with non-alcoholic fatty liver disease (NAFLD) have only steatosis without progression, a sizeable fraction develop non-alcoholic steatohepatitis (NASH), which can lead to cirrhosis and hepatocellular carcinoma (HCC). Many established diet-induced mouse models for NASH require 24-52 weeks, which makes testing for drug response costly and time consuming.

METHODS

We have sought to establish a murine NASH model with rapid progression of extensive fibrosis and HCC by using a western diet (WD), which is high-fat, high-fructose and high-cholesterol, combined with low weekly dose of intraperitoneal carbon tetrachloride (CCl₄), which serves as an accelerator.

RESULTS

C57BL/6J mice were fed a normal chow diet ± CCl₄ or WD ± CCl₄ for 12 and 24 weeks. Addition of CCl₄ exacerbated histological features of NASH, fibrosis, and tumor development induced by WD, which resulted in stage 3 fibrosis at 12 weeks and HCC development at 24 weeks. Furthermore, whole liver transcriptomic analysis indicated that dysregulated molecular pathways in WD/CCl₄ mice and immunologic features were similar to those of human NASH.

CONCLUSIONS

Our mouse NASH model exhibits rapid progression of advanced fibrosis and HCC, and mimics histological, immunological and transcriptomic features of human NASH, suggesting that it will be a useful experimental tool for preclinical drug testing.

LAY SUMMARY

A carefully characterized model has been developed in mice that recapitulates the progressive stages of human fatty liver disease, from simple steatosis, to inflammation, fibrosis and cancer. The functional pathways of gene expression and immune abnormalities in this model closely resemble human disease. The ease and reproducibility of this model make it ideal to study disease pathogenesis and test new treatments.

A pilot study of ultra-deep targeted sequencing of plasma DNA identifies driver mutations in hepatocellular carcinoma

Cellular components of solid tumors including DNA are released into the bloodstream, but data on circulating-free DNA (cfDNA) in hepatocellular carcinoma (HCC) are still scarce. This study aimed at analyzing mutations in cfDNA and their correlation with tissue mutations in patients with HCC. We included 8 HCC patients treated with surgical resection for whom we collected paired tissue and plasma/serum samples. We analyzed 45 specimens, including multiregional tumor tissue sampling (n = 24), peripheral blood mononuclear cells (PMBC, n = 8), plasma (n = 8) and serum (n = 5). Ultra-deep sequencing (5500× coverage) of all exons was performed in a targeted panel of 58 genes, including frequent HCC driver genes and druggable mutations. Mutations detected in plasma included known HCC oncogenes and tumor suppressors (e.g., TERT promoter, TP53, and NTRK3) as well as a candidate druggable mutation (JAK1). This approach increased the detection rates previously reported for mutations in plasma of HCC patients. A thorough characterization of cis mutations found in plasma confirmed their tumoral origin, which provides definitive evidence of the release of HCC-derived DNA fragments into the bloodstream. This study demonstrates that ultra-deep sequencing of cfDNA is feasible and can confidently detect somatic mutations found in tissue; these data reinforce the role of plasma DNA as a promising minimally invasive tool to interrogate HCC genetics.

Development of a novel histologic diagnostic algorithm for hepatic graft-versus-host disease

The histopathologic diagnosis of hepatic graft-versus-host disease post bone marrow and stem cell transplantation can be challenging, but timely and unambiguous diagnosis is essential for appropriate patient management. To address this diagnostic dilemma, we identified histologic features specific for hepatic graft-versus-host disease and developed a diagnostic algorithm. Two hepatopathologists blindly evaluated 40 liver biopsies from patients with clinically and biologically confirmed graft-versus-host disease, as well as 44 controls, for percent bile duct loss, bile duct damage, intraepithelial lymphocytes, ductular reaction, acidophilic bodies/10 high power fields (HPF), cholestasis, portal and lobular inflammation, and endotheliitis. Compared with controls, graft-versus-host disease cases had significantly more bile duct loss (P<0.0001), bile duct damage (P=0.0002), cholestasis (P<0.0001), and acidophilic bodies/10 HPF (P=0.0006), as well as significantly less ductular reaction (P<0.0001). Significance was maintained with a drug-induced liver injury-only control group. No histologic differences were noted in acute versus chronic graft-versus-host disease, nor cholestatic versus hepatitic types. An algorithm to predict likelihood of graft-versus-host disease was developed, with a three-tiered scoring system: 1-2 not, 3-4 probable, and 5-8 unequivocal graft-versus-host disease. This algorithm had a sensitivity of 93%, specificity of 93%, and accuracy of 92%. We identified histologic features with specificity for hepatic graft-versus-host disease and developed a simple algorithm for pathologists to predict its likelihood, distinguishing this critical diagnosis promptly from mimickers having vastly different treatments and prognoses.

Histological assessment of the liver explant in transplanted hepatitis C virus patients achieving sustained virological response with direct-acting antiviral agents

AIMS

The use of direct-acting anti-viral agents (DAAs) has resulted in extremely high sustained virological response (SVR) rates in patients being treated while on liver transplantation (LT) waiting lists. The aim of this study was to evaluate the histological findings of hepatitis C virus (HCV) patients who achieved SVR after receiving DAA treatment [SVR(+)] prior to LT, and compare them with HCV patients who had not achieved SVR [SVR(-)].

METHODS AND RESULTS

Fifty-eight adult HCV patients who underwent LT at our institution from 2014 to 2016 were included in the study. Two pathologists, blinded to SVR status, simultaneously evaluated the histological sections. Assessment included the Histology Activity Index (HAI/modified Knodell score), fibrosis stage (Ishak score), and Laennec cirrhosis stage. The study group comprised 25 SVR(+) patients (56% male; mean age, 63.8 years), and the control group comprised 33 SVR(-) patients (69% male; mean age, 61.7 years). There was no significant difference in HAI between the groups (P = 0.414). Patients who achieved SVR also did not show less portal inflammation (P = 0.787), interface hepatitis (P = 0.999), confluent necrosis (P = 0.627) or spotty necrosis (P = 0.093) than the control group. There was a trend towards a higher degree of inflammation in patients who achieved SVR in <24 weeks (P = 0.07). The degree of focal lytic necrosis/apoptosis and portal inflammation was more prominent in SVR(+) patients with shorter SVR-LT intervals.

CONCLUSIONS

Our study is the first to report persistent inflammation in HCV patients who received DAAs prior to LT. This supports the notion that inflammation is immunologically driven and that inflammation persists despite the absence of virus.

Osteopontin deletion drives hematopoietic stem cell mobilization to the liver and increases hepatic iron contributing to alcoholic liver disease

The aim of this study was to investigate the role of osteopontin (OPN) in hematopoietic stem cell (HPSC) mobilization to the liver and its contribution to alcoholic liver disease (ALD). We analyzed young (14-16 weeks) and old (>1.5 years) wild-type (WT) littermates and global Opn knockout (Opn-/- ) mice for HPSC mobilization to the liver. In addition, WT and Opn-/- mice were chronically fed the Lieber-DeCarli diet for 7 weeks. Bone marrow (BM), blood, spleen, and liver were analyzed by flow cytometry for HPSC progenitors and polymorphonuclear neutrophils (PMNs). Chemokines, growth factors, and cytokines were measured in serum and liver. Prussian blue staining for iron deposits and naphthol AS-D chloroacetate esterase staining for PMNs were performed on liver sections. Hematopoietic progenitors were lower in liver and BM of young compared to old Opn-/- mice. Granulocyte colony-stimulating factor and macrophage colony-stimulating factor were increased in Opn-/- mice, suggesting potential migration of HPSCs from the BM to the liver. Furthermore, ethanol-fed Opn-/- mice showed significant hepatic PMN infiltration and hemosiderin compared to WT mice. As a result, ethanol feeding caused greater liver injury in Opn-/- compared to WT mice. Conclusion: Opn deletion promotes HPSC mobilization, PMN infiltration, and iron deposits in the liver and thereby enhances the severity of ALD. The age-associated contribution of OPN to HPSC mobilization to the liver, the prevalence of PMNs, and accumulation of hepatic iron, which potentiates oxidant stress, reveal novel signaling mechanisms that could be targeted for therapeutic benefit in patients with ALD. (Hepatology Communications 2018;2:84-98).

A pilot systematic genomic comparison of recurrence risks of hepatitis B virus-associated hepatocellular carcinoma with low- and high-degree liver fibrosis

BACKGROUND

Chronic hepatitis B virus (HBV) infection leads to liver fibrosis, which is a major risk factor in hepatocellular carcinoma (HCC) and an independent risk factor of recurrence after HCC tumor resection. The HBV genome can be inserted into the human genome, and chronic inflammation may trigger somatic mutations. However, how HBV integration and other genomic changes contribute to the risk of tumor recurrence with regards to the different degree of liver fibrosis is not clearly understood.

METHODS

We sequenced mRNAs of 21 pairs of tumor and distant non-neoplastic liver tissues of HBV-HCC patients and performed comprehensive genomic analyses of our RNAseq data and public available HBV-HCC sequencing data.

RESULTS

We developed a robust pipeline for sensitively identifying HBV integration sites based on sequencing data. Simulations showed that our method outperformed existing methods. Applying it to our data, 374 and 106 HBV host genes were identified in non-neoplastic liver and tumor tissues, respectively. When applying it to other RNA sequencing datasets, consistently more HBV integrations were identified in non-neoplastic liver than in tumor tissues. HBV host genes identified in non-neoplastic liver samples significantly overlapped with known tumor suppressor genes. More significant enrichment of tumor suppressor genes was observed among HBV host genes identified from patients with tumor recurrence, indicating the potential risk of tumor recurrence driven by HBV integration in non-neoplastic liver tissues. We also compared SNPs of each sample with SNPs in a cancer census database and inferred samples' pathogenic SNP loads. Pathogenic SNP loads in non-neoplastic liver tissues were consistently higher than those in normal liver tissues. Additionally, HBV host genes identified in non-neoplastic liver tissues significantly overlapped with pathogenic somatic mutations, suggesting that HBV integration and somatic mutations targeting the same set of genes are important to tumorigenesis. HBV integrations and pathogenic mutations showed distinct patterns between low and high liver fibrosis patients with regards to tumor recurrence.

CONCLUSIONS

The results suggest that HBV integrations and pathogenic SNPs in non-neoplastic tissues are important for tumorigenesis and different recurrence risk models are needed for patients with low and high degrees of liver fibrosis.

Hepatitis C virus double-stranded RNA is the predominant form in human liver and in interferon-treated cells

Hepatitis C virus (HCV) is unique among RNA viruses in its ability to establish chronic infection in the majority of exposed adults. HCV persists in the liver despite interferon (IFN)-stimulated gene (ISG) induction; robust induction actually predicts treatment failure and viral persistence. It is unclear which forms of HCV RNA are associated with ISG induction and IFN resistance during natural infections. To thoroughly delineate HCV RNA populations, we developed conditions that fully separate the strands of long double-stranded RNA (dsRNA) and allow the released RNAs to be quantified in reverse transcription/polymerase chain reaction assays. These methods revealed that dsRNA, a pathogen-associated molecular pattern (PAMP), comprised 52% (standard deviation, 28%) of the HCV RNA in the livers of patients with chronic infection. HCV dsRNA was proportionally higher in patients with the unfavorable IL28B TT (rs12979860) genotype. Higher ratios of HCV double-stranded to single-stranded RNA (ssRNA) correlated positively with ISG induction. In Huh-7.5 cells, IFN treatment increased the total amount of HCV dsRNA through a process that required de novo viral RNA synthesis and shifted the ratio of viral dsRNA/ssRNA in favor of dsRNA. This shift was blocked by ribavirin (RBV), an antiviral drug that reduces relapse in HCV patients. Northern blotting established that HCV dsRNA contained genome-length minus strands.

CONCLUSION

HCV dsRNA is the predominant form in the HCV-infected liver and has features of both a PAMP and a genomic reservoir. Interferon treatment increased rather than decreased HCV dsRNA. This unexpected finding suggests that HCV produces dsRNA in response to IFN, potentially to antagonize antiviral defenses. (Hepatology 2017;66:357-370).

Mixed hepatocellular cholangiocarcinoma tumors: Cholangiolocellular carcinoma is a distinct molecular entity

BACKGROUND & AIMS

Mixed hepatocellular cholangiocarcinoma (HCC-CCA) is a rare and poorly understood type of primary liver cancer. We aimed to perform a comprehensive molecular characterization of this malignancy.

METHODS

Gene expression profiling, DNA copy number detection, and exome sequencing using formalin-fixed samples from 18 patients with mixed HCC-CCA were performed, encompassing the whole histological spectrum of the disease. Comparative genomic analysis was carried out, using independent datasets of HCC (n=164) and intrahepatic cholangiocarcinoma (iCCA) (n=149).

RESULTS

Integrative genomic analysis of HCC-CCAs revealed that cholangiolocellular carcinoma (CLC) represents a distinct biliary-derived entity compared with the stem-cell and classical types. CLC tumors were neural cell adhesion molecule (NCAM) positive (6/6 vs. 1/12, p<0.001), chromosomally stable (mean chromosomal aberrations 5.7 vs. 14.1, p=0.008), showed significant upregulation of transforming growth factor (TGF)-β signaling and enrichment of inflammation-related and immune response signatures (p<0.001). Stem-cell tumors were characterized by spalt-like transcription factor 4 (SALL4) positivity (6/8 vs. 0/10, p<0.001), enrichment of progenitor-like signatures, activation of specific oncogenic pathways (i.e., MYC and insulin-like growth factor [IGF]), and signatures related to poor clinical outcome. In the classical type, there was a significant correlation in the copy number variation of the iCCA and HCC components, suggesting a clonal origin. Exome sequencing revealed an average of 63 non-synonymous mutations per tumor (2 mean driver mutations per tumor). Among those, TP53 was the most frequently mutated gene (6/21, 29%) in HCC-CCAs.

CONCLUSIONS

Mixed HCC-CCA represents a heterogeneous group of tumors, with the stem-cell type characterized by features of poor prognosis, and the classical type with common lineage for HCC and iCCA components. CLC stands alone as a distinct biliary-derived entity associated with chromosomal stability and active TGF-β signaling.

LAY SUMMARY

Molecular analysis of mixed hepatocellular cholangiocarcinoma (HCC-CCA) showed that cholangiolocellular carcinoma (CLC) is distinct and biliary in origin. It has none of the traits of hepatocellular carcinoma (HCC). However, within mixed HCC-CCA, stem-cell type tumors shared an aggressive nature and poor outcome, whereas the classic type showed a common cell lineage for both the HCC and the intrahepatic CCA component. The pathological classification of mixed HCC-CCA should be redefined because of the new molecular data provided.

Imaging-based surrogate markers of transcriptome subclasses and signatures in hepatocellular carcinoma: preliminary results

OBJECTIVES

In this preliminary study, we examined whether imaging-based phenotypes are associated with reported predictive gene signatures in hepatocellular carcinoma (HCC).

METHODS

Thirty-eight patients (M/F 30/8, mean age 61 years) who underwent pre-operative CT or MR imaging before surgery as well as transcriptome profiling were included in this IRB-approved single-centre retrospective study. Eleven qualitative and four quantitative imaging traits (size, enhancement ratios, wash-out ratio, tumour-to-liver contrast ratios) were assessed by three observers and were correlated with 13 previously reported HCC gene signatures using logistic regression analysis.

RESULTS

Thirty-nine HCC tumours (mean size 5.7 ± 3.2 cm) were assessed. Significant positive associations were observed between certain imaging traits and gene signatures of aggressive HCC phenotype (G3-Boyault, Proliferation-Chiang profiles, CK19-Villanueva, S1/S2-Hoshida) with odds ratios ranging from 4.44-12.73 (P <0.045). Infiltrative pattern at imaging was significantly associated with signatures of microvascular invasion and aggressive phenotype. Significant but weak associations were also observed between each enhancement ratio and tumour-to-liver contrast ratios and certain gene expression profiles.

CONCLUSIONS

This preliminary study demonstrates a correlation between phenotypic imaging traits with gene signatures of aggressive HCC, which warrants further prospective validation to establish imaging-based surrogate markers of molecular phenotypes in HCC.

KEY POINTS

• There are associations between imaging and gene signatures of aggressive hepatocellular carcinoma. • Infiltrative type is associated with gene signatures of microvascular invasion and aggressiveness. • Infiltrative type may be a surrogate marker of microvascular invasion gene signature.

Frontline Science: HIV infection of Kupffer cells results in an amplified proinflammatory response to LPS

End-stage liver disease is a common cause of non-AIDS-related mortality in HIV⁺ patients, despite effective anti-retroviral therapies (ARTs). HIV-1 infection causes gut CD4 depletion and is thought to contribute to increased gut permeability, bacterial translocation, and immune activation. Microbial products drain from the gut into the liver via the portal vein where Kupffer cells (KCs), the resident liver macrophage, clear translocated microbial products. As bacterial translocation is implicated in fibrogenesis in HIV patients through unclear mechanisms, we tested the hypothesis that HIV infection of KCs alters their response to LPS in a TLR4-dependent manner. We showed that HIV-1 productively infected KCs, enhanced cell-surface TLR4 and CD14 expression, and increased IL-6 and TNF-α expression, which was blocked by a small molecule TLR4 inhibitor. Our study demonstrated that HIV infection sensitizes KCs to the proinflammatory effects of LPS in a TLR4-dependent manner. These findings suggest that HIV-1-infected KCs and their dysregulated innate immune response to LPS may play a role in hepatic inflammation and fibrosis and represent a novel target for therapy.

2016 Comprehensive Update of the Banff Working Group on Liver Allograft Pathology: Introduction of Antibody-Mediated Rejection

The Banff Working Group on Liver Allograft Pathology reviewed and discussed literature evidence regarding antibody-mediated liver allograft rejection at the 11th (Paris, France, June 5-10, 2011), 12th (Comandatuba, Brazil, August 19-23, 2013), and 13th (Vancouver, British Columbia, Canada, October 5-10, 2015) meetings of the Banff Conference on Allograft Pathology. Discussion continued online. The primary goal was to introduce guidelines and consensus criteria for the diagnosis of liver allograft antibody-mediated rejection and provide a comprehensive update of all Banff Schema recommendations. Included are new recommendations for complement component 4d tissue staining and interpretation, staging liver allograft fibrosis, and findings related to immunosuppression minimization. In an effort to create a single reference document, previous unchanged criteria are also included.

Prospective comparison of magnetic resonance imaging to transient elastography and serum markers for liver fibrosis detection

BACKGROUND & AIMS

Establishing accurate non-invasive methods of liver fibrosis quantification remains a major unmet need. Here, we assessed the diagnostic value of a multiparametric magnetic resonance imaging (MRI) protocol including diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE)-MRI and magnetic resonance elastography (MRE) in comparison with transient elastography (TE) and blood tests [including ELF (Enhanced Liver Fibrosis) and APRI] for liver fibrosis detection.

METHODS

In this single centre cross-sectional study, we prospectively enrolled 60 subjects with liver disease who underwent multiparametric MRI (DWI, DCE-MRI and MRE), TE and blood tests. Correlation was assessed between non-invasive modalities and histopathologic findings including stage, grade and collagen content, while accounting for covariates such as age, sex, BMI, HCV status and MRI-derived fat and iron content. ROC curve analysis evaluated the performance of each technique for detection of moderate-to-advanced liver fibrosis (F2-F4) and advanced fibrosis (F3-F4).

RESULTS

Magnetic resonance elastography provided the strongest correlation with fibrosis stage (r = 0.66, P < 0.001), inflammation grade (r = 0.52, P < 0.001) and collagen content (r = 0.53, P = 0.036). For detection of moderate-to-advanced fibrosis (F2-F4), AUCs were 0.78, 0.82, 0.72, 0.79, 0.71 for MRE, TE, DCE-MRI, DWI and APRI, respectively. For detection of advanced fibrosis (F3-F4), AUCs were 0.94, 0.77, 0.79, 0.79 and 0.70, respectively.

CONCLUSIONS

Magnetic resonance elastography provides the highest correlation with histopathologic markers and yields high diagnostic performance for detection of advanced liver fibrosis and cirrhosis, compared to DWI, DCE-MRI, TE and serum markers.

Intravoxel incoherent motion diffusion-weighted imaging of hepatocellular carcinoma: Is there a correlation with flow and perfusion metrics obtained with dynamic contrast-enhanced MRI?

PURPOSE

To assess the correlation between intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) metrics in hepatocellular carcinoma (HCC) and liver parenchyma.

MATERIALS AND METHODS

Twenty-five patients with HCC (M/F 23/2, mean age 58 years) underwent abdominal MRI at 1.5 or 3.0T, including IVIM-DWI (with 16 b-values) and DCE-MRI (3D FLASH sequence, mean temporal resolution of 2.3 sec). IVIM-DWI parameters (pseudodiffusion coefficient, D*, diffusion coefficient, D, and perfusion fraction, PF) were quantified in HCC lesions and liver parenchyma using a Bayesian fitting algorithm. DCE-MRI parameters (arterial flow, Fa , portal flow, Fp , total flow, Ft , mean transit time, MTT, distribution volume, DV, and arterial fraction, ART) were quantified using a dual-input single-compartment model. Correlations between IVIM-DWI and DCE-MRI parameters were assessed using a Spearman correlation test.

RESULTS

Thirty-three HCC lesions (average size 5.0 ± 3.6 cm) were analyzed. D, D*, and PF were all significantly lower in HCC vs. liver (P < 0.05). Significantly higher Fa and ART and lower Fp were observed in HCC vs. liver (P < 0.001). Significant moderate to strong negative correlations were observed between ART and D* (r = -0.443, P = 0.028), ART and PF (r = -0.536, P = 0.006), ART and PFxD* (r = -0.655, P < 0.001), Fa and PF (r = 0.455, P = 0.023), and Fa and PFxD* (r = -0.475, P = 0.018) in liver parenchyma. There was no significant correlation between IVIM-DWI and DCE-MRI metrics in HCC lesions.

CONCLUSION

IVIM-DWI and DCE-MRI provide nonredundant information in HCC, while they correlate in liver parenchyma. These findings may be secondary to predominant portal inflow in the liver and tortuous vasculature and tissue heterogeneity in tumors. J. MAGN. RESON. IMAGING 2016;44:856-864.

Autologous Tumor Cell Lysate-Loaded Dendritic Cell Vaccine Inhibited Tumor Progression in an Orthotopic Murine Model for Hepatocellular Carcinoma

The immune status of the tumor microenvironment influences tumor progression, and hepatocellular carcinoma (HCC) with an immunosuppressive signature often is associated with a poor prognosis. This study examined the impact of a bone marrow-derived dendritic cell (DC) vaccine loaded with autologous tumor cell lysate on tumor progression and the tumor microenvironment using an orthotopic murine HCC model. An orthotopic murine HCC was established by implantation of Hepa1-6 cells in the liver. The impact of DC vaccine loaded with Hepa1-6 cell lysate on tumor progression, survival, and tumor-infiltrating lymphocytes and cytokines was examined. Treating mice with DC vaccine loaded with Hepa1-6 cell lysate inhibited the progression of murine HCC generated through orthotopic implantation of Hepa1-6 cells and resulted in a 90 % survival rate by day 60 compared with a survival rate lower than 5 % for untreated mice. This anti-tumor response was associated with inhibition of STAT3 phosphorylation within the tumor. The DC vaccine reduced accumulation of Foxp3⁺CD4⁺ regulatory T cells within the tumor microenvironment and prevented TGF-β production from the tumor tissue. Tumor cell lysate-loaded DC vaccine prevented HCC progression in a clinically relevant orthotopic murine HCC model. The effect of DC vaccine on the accumulation of Foxp3⁺CD4⁺ regulatory T cells within the tumor microenvironment and on the production of TGF-β suggests that tumor regression by DC vaccination may be associated with an altered immunosuppressive tumor microenvironment.

Idiopathic Noncirrhotic Portal Hypertension: An Appraisal

Idiopathic noncirrhotic portal hypertension is a poorly defined clinical condition of unknown etiology. Patients present with signs and symptoms of portal hypertension without evidence of cirrhosis. The disease course appears to be indolent and benign with an overall better outcome than cirrhosis, as long as the complications of portal hypertension are properly managed. This condition has been recognized in different parts of the world in diverse ethnic groups with variable risk factors, resulting in numerous terminologies and lack of standardized diagnostic criteria. Therefore, although the diagnosis of idiopathic noncirrhotic portal hypertension requires clinical exclusion of other conditions that can cause portal hypertension and histopathologic confirmation, this entity is under-recognized clinically as well as pathologically. Recent studies have demonstrated that variable histopathologic entities with different terms likely represent a histologic spectrum of a single entity of which obliterative portal venopathy might be an underlying pathogenesis. This perception calls for standardization of the nomenclature and formulation of widely accepted diagnostic criteria, which will facilitate easier recognition of this disorder and will highlight awareness of this entity.

The Severity of Liver Fibrosis Influences the Prognostic Value of Inflammation-Based Scores in Hepatitis B-Associated Hepatocellular Carcinoma

BACKGROUND

This study was designed to evaluate the prognostic value of three systemic inflammation markers, neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and prognostic nutritional index (PNI), for hepatocellular carcinoma (HCC) associated with hepatitis B (HBV).

METHODS

This analysis included 234 HBV-HCC patients who underwent primary surgical resection at the Mount Sinai Medical Center between 1988 and 2013. Serum albumin and circulating neutrophil, lymphocyte, and platelet counts immediately before surgery were obtained to calculate NLR, PLR, and PNI.

RESULTS

Patients with larger tumor size (>3 cm) had higher NLR, higher PLR, and lower PNI. Stratified analysis showed that the impact of three markers on outcome depends on the severity of liver fibrosis. High NLR, high PLR, or low PNI was associated with poor outcome only in patients without end-stage fibrosis (Ishak stage 0-5) and not in those with cirrhosis (Ishak stage 6). Multivariate analysis in Ishak stage 0-5 patients showed that only high NLR was associated with poor outcome independent of tumor size. Of the three markers, only NLR correlated with PD-L1 expression in center of tumor, but not in nonneoplastic liver.

CONCLUSIONS

The prognostic value of these three markers following surgery was only significant for HBV-HCC patients without end-stage fibrosis, and among the three markers, only NLR remained a significant prognostic indicator independent of tumor size. The correlation of NLR with intratumoral PD-L1 expression raises a hypothesis for shared pathways leading to PD-L1-mediated local tolerance within tumor and systemic inflammatory responses represented by elevated NLR in HBV-HCC.