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.

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.

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.

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.