FGF21 protects against ischaemia reperfusion injury in normal and fatty livers

BACKGROUND

Liver ischaemia/reperfusion (I/R) injury, which is an inevitable clinical problem of liver resection, liver transplantation and haemorrhagic shock. Fibroblast growth factor 21 (FGF21) was intimately coupled with multiple metabolic processes and proved to protect against apoptosis and inflammatory response in hepatocytes during hepatic I/R injury. However, the regulatory mechanisms of FGF21 in hepatic I/R injury remains unknown. Therefore, we hypothesize that FGF21 protects hepatic tissues from I/R injury.

METHODS

Blood samples were available from haemangiomas patients undergoing hepatectomy and murine liver I/R model and used to further evaluate the serum levels of FGF21 both in humans and mice. We further explored the regulatory mechanisms of FGF21 in murine liver I/R model by using FGF21-knockout mice (FGF21-KO mice) and FGF21-overexpression transgenic mice (FGF21-OE mice) fed a high-fat or ketogenic diet.

RESULTS

Our results show that the circulating levels of FGF21 were robustly decreased after liver I/R in both humans and mice. Silencing FGF21 expression with FGF21-KO mice aggravates liver injury at 6 h after 75 min of partial liver ischaemia, while FGF21-OE mice display alleviated hepatic I/R injury and inflammatory response. Compared with chow diet mice, exogenous FGF21 decreases the levels of aminotransferase, histological changes, apoptosis and inflammatory response in hepatic I/R injury treatment mice with a high-fat diet. Meanwhile, ketogenic diet mice are not sensitive to hepatic I/R injury.

CONCLUSIONS

The circulating contents of FGF21 are decreased during liver warm I/R injury and exogenous FGF21 exerts hepatoprotective effects on hepatic I/R injury. Thus, FGF21 regulates hepatic I/R injury and may be a key therapeutic target.

Characterizing Metabolic Heterogeneity of Hepatocellular Carcinoma with Hyperpolarized 13C Pyruvate MRI and Mass Spectrometry

Purpose To characterize the metabolomic profiles of two hepatocellular carcinoma (HCC) rat models, track evolution of these profiles to a stimulated tumor state, and assess their effect on lactate flux with hyperpolarized (HP) carbon 13 (13C) MRI. Materials and Methods Forty-three female adult Fischer rats were implanted with N1S1 or McA-RH7777 HCC tumors. In vivo lactate-to-pyruvate ratio (LPR) was measured with HP 13C MRI at 9.4 T. Ex vivo mass spectrometry was used to measure intratumoral metabolites, and Ki67 labeling was used to quantify proliferation. Tumors were first compared with three normal liver controls. The tumors were then compared with stimulated variants via off-target hepatic thermal ablation treatment. All comparisons were made using the Mann-Whitney test. Results HP 13C pyruvate MRI showed greater LPR in N1S1 tumors compared with normal liver (mean [SD], 0.564 ± 0.194 vs 0.311 ± 0.057; P < .001 [n = 9]), but not for McA-RH7777 (P = .44 [n = 8]). Mass spectrometry confirmed that the glycolysis pathway was increased in N1S1 tumors and decreased in McA-RH7777 tumors. The pentose phosphate pathway was also decreased only in McA-RH7777 tumors. Increased proliferation in stimulated N1S1 tumors corresponded to a net increase in LPR (six stimulated vs six nonstimulated, 0.269 ± 0.148 vs 0.027 ± 0.08; P = .009), but not in McA-RH7777 (eight stimulated vs six nonstimulated, P = .13), despite increased proliferation and metastases. Mass spectrometry demonstrated relatively increased lactate production with stimulation in N1S1 tumors only. Conclusion Two HCC subtypes showed divergent glycolytic dependency at baseline and during transformation to a high proliferation state. This metabolic heterogeneity in HCC should be considered with use of HP 13C MRI for diagnosis and tracking. Keywords: Molecular Imaging-Probe Development, Liver, Abdomen/GI, Oncology, Hepatocellular Carcinoma © RSNA, 2024 See also commentary by Ohliger in this issue.

ASK1/ p38 axis inhibition blocks the release of mitochondrial "danger signals" from hepatocytes and suppresses progression to cirrhosis and liver cancer

BACKGROUND AND AIMS

Apoptosis Signal-regulating Kinase 1 (ASK1) is activated by various pathological stimuli and induces cell apoptosis through downstream p38 activation. We studied the effect of pharmacological ASK1 inhibition on cirrhosis and its sequelae using comprehensive preclinical in vivo and in vitro systems.

APPROACH AND RESULTS

Short-term (4-6 wk) and long-term (24-44 wk) ASK1 inhibition using small molecule GS-444217 was tested in thioacetamide-induced and BALB/c. Mdr2-/- murine models of cirrhosis and HCC, and in vitro using primary hepatocyte cell death assays. Short-term GS-444217 therapy in both models strongly reduced phosphorylated p38, hepatocyte death, and fibrosis by up to 50%. Profibrogenic release of mitochondrial DAMP mitochondrial deoxyribonucleic acid from dying hepatocytes was blocked by ASK1 or p38 inhibition. Long-term (24 wk) therapy in BALBc.Mdr2 - / - model resulted in a moderate 25% reduction in bridging fibrosis, but not in net collagen deposition. Despite this, the development of cirrhosis was effectively prevented, with strongly reduced p21 + hepatocyte staining (by 72%), serum ammonia levels (by 46%), and portal pressure (average 6.07 vs. 8.53 mm Hg in controls). Extended ASK1 inhibition for 44 wk in aged BALB/c. Mdr2-/- mice resulted in markedly reduced tumor number and size by ~50% compared to the control group.

CONCLUSIONS

ASK1 inhibition suppresses the profibrogenic release of mitochondrial deoxyribonucleic acid from dying hepatocytes in a p38-dependent manner and protects from liver fibrosis. Long-term ASK1 targeting resulted in diminished net antifibrotic effect, but the progression to liver cirrhosis and cancer in BALBc/ Mdr2- / - mice was effectively inhibited. These data support the clinical evaluation of ASK1 inhibitors in fibrotic liver diseases.

Ciliated foregut cysts involving the hepatopancreaticobiliary system: a clinicopathological evaluation with focus on atypical features

AIMS

Foregut cystic malformations are rare developmental abnormalities, which may involve the hepatopancreaticobiliary tract (HPBT). These cysts are composed of inner ciliated epithelium; subepithelial connective tissue layer; smooth muscle layer; and an outer fibrous layer. While radiopathologic findings are often diagnostic, atypical location and histologic features can pose a diagnostic challenge. We aimed to study ciliated foregut cysts (CFCs) in the HPBT, assess their clinicopathological features with a focus on atypical features.

METHODS

We collected cases of CFCs involving the HPBT from three large academic medical centres. H&E-stained slides and immunohistochemical stains (where available) were reviewed for each case. Relevant demographic, clinical and pathological information was collected from the medical records.

RESULTS

21 cases were identified. The median age was 53 years (range, 3-78 years). 17 cysts were identified within the liver (segment 4 was the most common location, n=10) and 4 in the pancreas. Cysts were mostly identified incidentally (n=13), abdominal pain was a common symptom (n=5). Cyst size ranged from 0.7 to 17.0 cm (median, 2.5 cm). Radiological findings were available in 17 cases. Cilia were identified in all cases. 19 of 21 cases demonstrated the presence of a smooth muscle layer (thickness, <0.1 mm to 3.0 mm). Three cases showed gastric metaplasia, while one case revealed additional low-grade dysplasia, with features similar to intraductal papillary neoplasm of the bile duct.

CONCLUSIONS

We highlight clinicopathological features of CFCs in the HPBT. The histomorphology is usually straightforward; however, unusual location and atypical features can pose a diagnostic challenge.

PFKFB3-mediated Pro-glycolytic Shift in Hepatocellular Carcinoma Proliferation

BACKGROUND & AIMS

Metabolic reprogramming, in particular, glycolytic regulation, supports abnormal survival and growth of hepatocellular carcinoma (HCC) and could serve as a therapeutic target. In this study, we sought to identify glycolytic regulators in HCC that could be inhibited to prevent tumor progression and could also be monitored in vivo, with the goal of providing a theragnostic alternative to existing therapies.

METHODS

An orthotopic HCC rat model was used. Tumors were stimulated into a high-proliferation state by use of off-target liver ablation and were compared with lower-proliferating controls. We measured in vivo metabolic alteration in tumors before and after stimulation, and between stimulated tumors and control tumors using hyperpolarized 13C magnetic resonance imaging (MRI) (h13C MRI). We compared metabolic alterations detected by h13C MRI to metabolite levels from ex vivo mass spectrometry, mRNA levels of key glycolytic regulators, and histopathology.

RESULTS

Glycolytic lactate flux increased within HCC tumors 3 days after tumor stimulation, correlating positively with tumor proliferation as measured with Ki67. This was associated with a shift towards aerobic glycolysis and downregulation of the pentose phosphate pathway detected by mass spectrometry. MRI-measured lactate flux was most closely coupled with PFKFB3 expression and was suppressed with direct inhibition using PFK15.

CONCLUSIONS

Inhibition of PFKFB3 prevents glycolytic-mediated HCC proliferation, trackable by in vivo h13C MRI.

Heme oxygenase-1 mitigates liver injury and fibrosis via modulation of LNX1/Notch1 pathway in myeloid cells

Activation of resident macrophages (Mϕ) and hepatic stellate cells is a key event in chronic liver injury. Mice with heme oxygenase-1 (HO-1; Hmox1)-deficient Mϕ (LysM-Cre:Hmox1 ^flfl ) exhibit increased inflammation, periportal ductular reaction, and liver fibrosis following bile duct ligation (BDL)-induced liver injury and increased pericellular fibrosis in NASH model. RiboTag-based RNA-sequencing profiling of hepatic HO-1-deficient Mϕ revealed dysregulation of multiple genes involved in lipid and amino acid metabolism, regulation of oxidative stress, and extracellular matrix turnover. Among these genes, ligand of numb-protein X1 (LNX1) expression is strongly suppressed in HO-1-deficient Mϕ. Importantly, HO-1 and LNX1 were expressed by hepatic Mϕ in human biliary and nonbiliary end-stage cirrhosis. We found that Notch1 expression, a downstream target of LNX1, was increased in LysM-Cre:Hmox1 ^flfl mice. In HO-1-deficient Mϕ treated with heme, transient overexpression of LNX1 drives M2-like Mϕ polarization. In summary, we identified LNX1/Notch1 pathway as a downstream target of HO-1 in liver fibrosis.

Differential Associations of Circulating MicroRNAs With Pathogenic Factors in NAFLD

Nonalcoholic fatty liver disease (NAFLD) is a heterogeneous disease driven by genetic and environmental factors. MicroRNAs (miRNAs) serve as pleiotropic post‐transcriptional regulators of cellular pathways. Although several miRNAs have been associated with NAFLD and fibrosis, there are limited studies in humans examining their differential association with pathogenic factors or histological features of NAFLD. We examined the differential relationships of five of the best‐described circulating microRNAs (miR‐34a, miR‐122, miR‐191, miR‐192, and miR‐200a) with histological features and pathogenic factors of NAFLD. A cross‐sectional study was conducted to examine the relationship between relative levels of circulating microRNAs standardized by z‐scores and histological features of NAFLD, common NAFLD genetic polymorphisms, and insulin resistance measured by the enhanced lipoprotein insulin resistance index in 132 subjects with biopsy‐proven NAFLD. We found that miR‐34a, miR‐122, miR‐192, miR‐200a, but not miR‐191, strongly correlate with fibrosis in NAFLD by increases of 0.20 to 0.40 SD (P < 0.005) with each stage of fibrosis. In multivariate analysis, miR‐34a, miR‐122, and miR‐192 levels are independently associated with hepatic steatosis and fibrosis, but not lobular inflammation or ballooning degeneration, whereas miR‐200a is only associated with fibrosis. Among the four miRNAs, miR‐34a, miR‐122, and miR‐192 are associated with pathogenic factors of NAFLD, including insulin resistance measured by eLP‐IR, patatin‐like phospholipase domain containing 3 I148M, and transmembrane 6 superfamily 2 (TM6SF2) E167K polymorphisms. In contrast, miR‐200a is only associated with the TM6SF2 E167K variant. Finally, miR‐34a has the strongest predictive value for various stages of fibrosis, with C‐statistic approximates–combined predictive score for miRNAs. Conclusion: miR‐34a, miR‐122, miR‐192, and miR‐200a demonstrate strong associations with NAFLD severity by histology, but differential associations with pathogenic factors.

Comparison of murine steatohepatitis models identifies a dietary intervention with robust fibrosis, ductular reaction, and rapid progression to cirrhosis and cancer

Progressive fibrosis, functional liver failure, and cancer are the central liver-related outcomes of nonalcoholic steatohepatitis (NASH) but notoriously difficult to achieve in mouse models. We performed a direct, quantitative comparison of hepatic fibrosis progression in well-defined methionine- and choline-deficient (MCD) and choline-deficient, amino-acid defined (CDAA) diets with increasing fat content (10-60% by calories) in C57Bl/6J and BALB/cAnNCrl mice. In C57Bl/6J mice, MCD feeding resulted in moderate fibrosis at week 8 (up to twofold increase in total hepatic collagen content) and progressive weight loss irrespective of dietary fat. In contrast, CDAA-fed mice did not lose weight and developed progressive fibrosis starting from week 4. High dietary fat in the CDAA diet model induced the lipid metabolism genes for sterol regulatory element-binding protein and stearoyl-CoA desaturase-2 and increased ductular reaction and fibrosis in a dose-dependent manner. Longitudinal analysis of CDAA with 60% fat (HF-CDAA) feeding revealed pronounced ductular reaction and perisinusoidal bridging fibrosis, with a sevenfold increase of hepatic collagen at week 12, which showed limited spontaneous reversibility. At 24 wk, HF-CDAA mice developed signs of cirrhosis with pan-lobular "chicken wire" fibrosis, 10-fold hydroxyproline increase, regenerative nodules, portal hypertension and elevated serum bilirubin and ammonia levels; 80% of mice (8/10) developed multiple glypican-3- and/or glutamine synthetase-positive hepatocellular carcinomas (HCC). High-fat (60%) supplementation of MCD in C57Bl/6J or feeding the HF-CDAA diet fibrosis-prone BALB/cAnNCrl strain failed to result in increased fibrosis. In conclusion, HF-CDAA feeding in C57Bl/6J mice was identified as an optimal model of steatohepatitis with robust fibrosis and ductular proliferations that progress to cirrhosis and HCC within 24 wk. This robust model will aid the testing of interventions and drugs for severe NASH.NEW & NOTEWORTHY Via quantitative comparison of several dietary models, we report HF-CDAA feeding in C57Bl/6 mice as an excellent model recapitulating several key aspects of fibrotic NASH: 1) robust, poorly reversible liver fibrosis, 2) prominent ductular reaction, and 3) progression to cirrhosis, portal hypertension, and liver cancer within 24 wk. High fat dose-dependently activates SREBP2/SCD2 genes and drives liver fibrosis in e HF-CDAA model. These features qualify the model as a robust and practical tool to study mechanisms and novel treatments addressing severe human NASH.

A Pathophysiologic Approach Combining Genetics and Insulin Resistance to Predict the Severity of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a complex disease dictated by both genetic and environmental factors. While insulin resistance (IR) is a key pathogenic driver, two common genetic variants in patatin‐like phospholipase domain containing 3 (PNPLA3) and transmembrane 6 superfamily member 2 (TM6SF2) also impart significant risk for disease progression. Traditional approaches to NAFLD risk stratification rely on biomarkers of fibrosis, an end result of disease progression. We hypothesized that by combining genetics and a novel measurement for IR we could predict disease progression by the NAFLD activity score (NAS) and histologic presence of significant fibrosis. A total of 177 patients with biopsy‐proven NAFLD were enrolled in this cross‐sectional study. PNPLA3 I148M and TM6SF2 E167K genotypes were determined by TaqMan assays. The enhanced lipoprotein IR index (eLP‐IR) was calculated from serum biomarkers using nuclear magnetic resonance (NMR) spectroscopy. Multivariate regression models were used to study the relationships between genetics, IR, and histologic features of NAFLD. In the multivariate analysis, the eLP‐IR was strongly associated with histologic features of NAFLD activity and hepatic fibrosis (P < 0.001 to 0.02) after adjustment for potential confounders. PNPLA3 148M and TM6SF2 E167K genotypes were significantly associated with steatosis (P = 0.003 and P = 0.02, respectively). A combination of the eLP‐IR and genetic score was able to predict the presence of NAS ≥3 with an area under the receiver operating characteristic curve (AUROC) of 0.74. Adding age to this model predicted stages 3‐4 liver fibrosis with an AUROC of 0.82. Conclusion: This proof‐of‐concept study supports the hypothesis that genetics and IR are major determinants of NAFLD severity and demonstrates the feasibility of a new risk stratification paradigm using exclusively pathogenic factors.

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.

A genomic case study of mixed fibrolamellar hepatocellular carcinoma

We report the first comprehensive genomic analysis of a case of mixed conventional and fibrolamellar HCC (mFL-HCC). This study confirms the expression of DNAJB1:PRKACA, a fusion previously associated with pure FL-HCC but not conventional HCC, in mFL-HCC. These results indicate the DNAJB1:PRKACA fusion has diagnostic utility for both pure and mixed FL-HCC.

Background

Mixed fibrolamellar hepatocellular carcinoma (mFL-HCC) is a rare liver tumor defined by the presence of both pure FL-HCC and conventional HCC components, represents up to 25% of cases of FL-HCC, and has been associated with worse prognosis. Recent genomic characterization of pure FL-HCC identified a highly recurrent transcript fusion (DNAJB1:PRKACA) not found in conventional HCC.

Patients and Methods

We performed exome and transcriptome sequencing of a case of mFL-HCC. A novel BAC-capture approach was developed to identify a 400 kb deletion as the underlying genomic mechanism for a DNAJB1:PRKACA fusion in this case. A sensitive Nanostring Elements assay was used to screen for this transcript fusion in a second case of mFL-HCC, 112 additional HCC samples and 44 adjacent non-tumor liver samples.

Results

We report the first comprehensive genomic analysis of a case of mFL-HCC. No common HCC-associated mutations were identified. The very low mutation rate of this case, large number of mostly single-copy, long-range copy number variants, and high expression of ERBB2 were more consistent with previous reports of pure FL-HCC than conventional HCC. In particular, the DNAJB1:PRKACA fusion transcript specifically associated with pure FL-HCC was detected at very high expression levels. Subsequent analysis revealed the presence of this fusion in all primary and metastatic samples, including those with mixed or conventional HCC pathology. A second case of mFL-HCC confirmed our finding that the fusion was detectable in conventional components. An expanded screen identified a third case of fusion-positive HCC, which upon review, also had both conventional and fibrolamellar features. This screen confirmed the absence of the fusion in all conventional HCC and adjacent non-tumor liver samples.

Conclusion

These results indicate that mFL-HCC is similar to pure FL-HCC at the genomic level and the DNAJB1:PRKACA fusion can be used as a diagnostic tool for both pure and mFL-HCC.

Intrahepatic distribution of hepatitis B virus antigens in patients with and without hepatocellular carcinoma

AIM: To study the intrahepatic expression of hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) in chronic hepatitis B patients with and without hepatocellular carcinoma.

METHODS: A total of 33 chronic hepatitis B patients (mean age of 40.3 ± 2.5 years), comprising of 14 HBeAg positive and 19 HBeAg negative patients; and 13 patients with hepatitis B virus related hepatocellular carcinoma (mean age of 49.6 ± 4.7 years), were included in our study. Immunohistochemical staining for HBcAg and HBsAg was done using standard streptavidin-biotin-immunoperoxidase technique on paraffin-embedded liver biopsies. The HBcAg and HBsAg staining distributions and patterns were described according to a modified classification system.

RESULTS: Compared to the HBeAg negative patients, the HBeAg positive patients were younger, had higher mean HBV DNA and alanine transaminases levels. All the HBeAg positive patients had intrahepatic HBcAg staining; predominantly with “diffuse” distribution (79%) and “mixed cytoplasmic/nuclear” pattern (79%). In comparison, only 5% of the HBeAg-negative patients had intrahepatic HBcAg staining. However, the intrahepatic HBsAg staining has wider distribution among the HBeAg negative patients, namely; majority of the HBeAg negative cases had “patchy” HBsAg distribution compared to “rare” distribution among the HBeAg positive cases. All but one patient with HCC were HBeAg negative with either undetectable HBV DNA or very low level of viremia. Intrahepatic HBcAg and HBsAg were seen in 13 (100%) and 10 (77%) of the HCC patients respectively. Interestingly, among the 9 HCC patients on anti-viral therapy with suppressed HBV DNA, HBcAg and HBsAg were detected in tumor tissues but not the adjacent liver in 4 (44%) and 1 (11%) patient respectively.

CONCLUSION: Isolated intrahepatic HBcAg and HBsAg can be present in tumors of patients with suppressed HBV DNA on antiviral therapy; that may predispose them to cancer development.

Poor Inter-test Reliability Between CK18 Kits as a Biomarker of NASH

BACKGROUND AND AIM

Nonalcoholic fatty liver disease (NAFLD) affects 15-40% of the general population; 10-20% of those patients have a more severe form of the disease known as nonalcoholic steatohepatitis (NASH). Cytokeratin-18 (CK18), released during apoptosis and one of the most studied biomarkers in NASH, can be measured by a number of commercially available kits. We compared serum measurements of the CK18 M30 from two different kits using the same cohort to evaluate the reliability between two test kits.

METHODS

We measured serum levels of CK18 M30 from 185 patients with biopsy-proven NAFLD from a single center from 2009 to 2015, using two different ELISA kits, Test 1 (T1) and Test 2 (T2). Advanced fibrosis was defined as fibrosis stages 3-4 and NASH defined by NAS score ≥ 5.

RESULTS

Mean age was 50.2 years (SD 12.6), 61.1% male and 87% White; 49.6% had NASH and 32.2% advanced fibrosis. There was no significant correlation between measurements from the two kits (p = 0.86, r = 0.01). While T2 predicted NASH and advanced fibrosis, T1 did not. The area under ROC curve for the prediction of NASH was 0.631 for T2 versus 0.500 for T1.

CONCLUSIONS

Measurements from two different CK18 M30 test kits did not correlate with each other. One kit showed statistically significantly higher levels of CK18 M30 in patients with advanced fibrosis and NASH, while the other kit did not. With the increasing use of CK18 as a biomarker in NASH, it is important to standardize the different kits as it could greatly bias the results.

Accuracy of fibroscan, compared with histology, in analysis of liver fibrosis in patients with hepatitis B or C: a United States multicenter study

BACKGROUND & AIMS

Liver biopsy is invasive and associated with complications, sampling errors, and observer variability. Vibration-controlled transient elastography (VCTE) with FibroScan can be used to immediately assess liver stiffness. We aimed to define optimal levels of liver stiffness to identify patients with chronic viral hepatitis and significant fibrosis, advanced fibrosis, or cirrhosis.

METHODS

In a prospective, 2-phase study, patients with chronic hepatitis C or B underwent VCTE followed by liver biopsy analysis from January 2005 through May 2008 at 6 centers in the United States. In phase 1 we identified optimal levels of liver stiffness for identification of patients with stage F2-F4 or F4 fibrosis (the development phase, n = 188). In phase 2 we tested these cutoff values in a separate cohort of patients (the validation phase, n = 560). All biopsies were assessed for METAVIR stage by a single pathologist in the phase 1 analysis and by a different pathologist in the phase 2 analysis. Diagnostic performances of VCTE were assessed by area under the receiver operating characteristic curve (AUROC) analyses.

RESULTS

In phase 1 of the study, liver stiffness measurements identified patients with ≥ F2 fibrosis with AUROC value of 0.89 (95% confidence interval, 0.83-0.92) and identified patients with F4 fibrosis with AUROC value of 0.92 (95% confidence interval, 0.87-0.95). Liver stiffness cutoff values (kPa) in phase 1 were 8.4 for ≥ F2 (82% sensitivity, 79% specificity) and 12.8 for F4 (84% sensitivity, 86% specificity). In the phase 2 analysis, the liver stiffness cutoff values identified patients with ≥ F2 fibrosis with 58% sensitivity (P < .0001 vs phase 1) and 75% specificity (nonsignificant difference vs phase 1); they identified patients with F4 fibrosis with 76% sensitivity (P < .0001 vs phase 1) and 85% specificity (nonsignificant differences vs phase 1). VCTE had an interobserver agreement correlation coefficient of 0.98 (n = 26) and an intraobserver agreement correlation coefficient of 0.95 (n = 34).

CONCLUSIONS

In a large U.S. multicenter study, we confirmed that VCTE provides an accurate assessment of liver fibrosis in patients with chronic viral hepatitis. Our findings are similar to those from European and Asian cohorts.

A new Mdr2(-/-) mouse model of sclerosing cholangitis with rapid fibrosis progression, early-onset portal hypertension, and liver cancer

We previously characterized the Mdr2(Abcb4)(-/-) mouse as a reproducible model of chronic biliary liver disease. However, it demonstrates relatively slow fibrosis progression, possibly due to its fibrosis-resistant genetic background. We aimed to improve the model by moving it onto a fibrosis-susceptible background. We generated novel BALB/c.Mdr2(-/-) mouse via genetic backcross onto highly fibrosis-susceptible BALB/c substrain, identified in inbred mouse strain screening. Liver fibrosis, portal pressure, and hepatic tumor burden in BALB/c.Mdr2(-/-) mice were studied up to 1 year of age in direct comparison to parental strain FVB.Mdr2(-/-). BALB/c.Mdr2(-/-) mice developed periductular onion-skin type fibrotic lesions and pronounced ductular reaction starting from 4 weeks of age. Compared to parental strain, BALB/c.Mdr2(-/-) mice demonstrated dramatically accelerated liver fibrosis, with threefold increase in collagen deposition and bridging fibrosis/early signs of cirrhosis at 12 weeks. This was accompanied by early-onset severe portal hypertension and twofold to fourfold increase in profibrogenic transcripts Col1a1 [procollagen α1(I)], Tgfb1, and Timp1. Primary liver cancers in BALB/c.Mdr2(-/-) developed earlier, with greater tumor burden compared to FVB.Mdr2(-/-). BALB/c.Mdr2(-/-) mice have unprecedented degree and rapidity of hepatic fibrosis progression and clinically relevant cirrhosis complications, such as early-onset portal hypertension and primary liver cancers. This new model will facilitate development of antifibrotic drugs and studies into mechanisms of biliary fibrosis progression.

Assessment of liver fat in an obese patient population using noncontrast CT fat percent index

OBJECTIVE

To develop a simplified method to quantify liver fat using computed tomography (CT) fat % index (CTFPI) compared to liver spleen method (CTL/S, CTL-S).

METHODS

Noncontrast CT of the liver was performed in 89 patients (overweight, obese, severely obese) to quantify fat, using the following: CTFPI=[(65-patient HU)/65]×100, normal live r=65 HU.

RESULTS

There was a strong linear correlation between CTFPI and the standard method of assessing liver fat using CTL/S (r=-0.901), CTL-S (r=-0.911). Hepatic HU and CTFPI were significantly different in the severely obese group compared to other two groups (P<.05).

CONCLUSION

Significant correlation indicates equal diagnostic accuracy of the two methods in appropriately calibrated scanners.

Response to Brosch et al

We would like to respond to Brosch et al. regarding our manuscript "Expression of the Splicing Factor Gene SFRS10 Is Reduced in Human Obesity and Contributes to Enhanced Lipogenesis" (Pihlajamäki et al., 2011b). Brosch performed RT-PCR in liver samples from 13 lean and 34 obese individuals, finding no differences in SFRS10 or LPIN1 expression. We wish to address points raised by Brosch, including experimental strategy and analysis of human SFRS10 expression.

Transient elastography for predicting clinical outcomes in patients with chronic liver disease

There is increasing interest in developing noninvasive means to evaluate liver fibrosis in patients with chronic liver disease to determine disease severity, prognosis and optimal treatment. Transient elastography (TE) has previously been demonstrated to predict the presence or absence of advanced fibrosis. The current study was conducted to determine whether TE can identify patients with chronic liver disease at risk of clinical decompensation. A total of 667 patients underwent TE and were followed for a median of 861 days and 57 patients achieved the primary outcome, a composite of clinical endpoints including death, ascites, encephalopathy, increased Child Score ≥ 2, variceal bleed, hepatocellular carcinoma or listing for transplant. Overall, TE had an area under the receiver operating characteristic curve of 0.87 for predicting clinical outcome. Using a cut-off of 10.5 kPa, TE has a sensitivity, specificity, positive predictive value and negative predictive value (NPV) of 94.7%, 63.0%, 19.3% and 99.2%, respectively. A predictive model for clinical events was developed using generalized cross-validation for clinical endpoints considering TE, liver biopsy results and multiple other predictors. Individually, TE performed better than biopsy, or any other variable, for predicting clinical outcome [Harrell's C Statistic 0.86 for TE, 0.78 for stage]. Patients with a TE score of >12.5 kPa were found to have a relative hazard for clinical event of 18.99 compared with patients with TE score <10.5. A combined variable model including TE, aspartate aminotransferase/alanine aminotransferase ratio and model for end-stage liver disease (MELD) yielded the highest predictive accuracy with Harrell's C value of 0.93. In the subset of patients with cirrhosis, TE was not found to be independently associated with clinical outcomes in univariate or multivariate analysis although it retained a high sensitivity and NPV of 97.5% and 92.3%, respectively, at a kPa cut-off of 10.5. TE can successfully identify patients with chronic liver disease who are at low risk of clinical decompensation over a time period of 2 years.

Expression of the splicing factor gene SFRS10 is reduced in human obesity and contributes to enhanced lipogenesis

Alternative mRNA splicing provides transcript diversity and may contribute to human disease. We demonstrate that expression of several genes regulating RNA processing is decreased in both liver and skeletal muscle of obese humans. We evaluated a representative splicing factor, SFRS10, downregulated in both obese human liver and muscle and in high-fat-fed mice, and determined metabolic impact of reduced expression. SFRS10-specific siRNA induces lipogenesis and lipid accumulation in hepatocytes. Moreover, Sfrs10 heterozygous mice have increased hepatic lipogenic gene expression, VLDL secretion, and plasma triglycerides. We demonstrate that LPIN1, a key regulator of lipid metabolism, is a splicing target of SFRS10; reduced SFRS10 favors the lipogenic β isoform of LPIN1. Importantly, LPIN1β-specific siRNA abolished lipogenic effects of decreased SFRS10 expression. Together, our results indicate that reduced expression of SFRS10, as observed in tissues from obese humans, alters LPIN1 splicing, induces lipogenesis, and therefore contributes to metabolic phenotypes associated with obesity.

Comparison of transient elastography, serum markers and clinical signs for the diagnosis of compensated cirrhosis

BACKGROUND AND AIMS

Non-invasive diagnosis of compensated cirrhosis is important. We therefore compared liver stiffness by transient elastography, APRI score, AST/ALT ratio, hyaluronic acid and clinical signs to determine which modality performed best at identifying compensated cirrhosis.

METHODS

Patients undergoing evaluation at a single center were recruited and had clinical, serological, endoscopy, radiological imaging, liver stiffness measurement and liver biopsy. Patients were stratified into cirrhotic and non-cirrhotic.

RESULTS

In 404 patients (124 cirrhosis), transient elastography was diagnostically superior to the other modalities yielding an AUC 0.9 +/- 0.04 compared with hyaluronic acid (AUC 0.81 +/- 0.04: P < 0.05), clinical signs (AUC 0.74 +/- 0.04: P < 0.05), APRI score (AUC 0.71 +/- 0.03: P < 0.05) and AST/ALT ratio (AUC 0.66 +/- 0.03: P < 0.05). The optimum cut-off for transient elastography was 12 kPa giving a sensitivity of 89% and specificity of 87% for cirrhosis. In 238 hepatitis C patients (87 cirrhosis), transient elastography yielded an AUC 0.899 +/- 0.02 for cirrhosis and in 166 non-HCV patients (37 cirrhosis) the results were similar with an AUC 0.928 +/- 0.03; with transient elastography being superior to HA, APRI, AST/ALT and clinical signs for all etiologies of cirrhosis (P < 0.05 for all). Importantly, transient elastography was statistically superior at identifying cirrhosis in 38 biopsy proven Childs Pugh A cirrhotics with no clinical, biochemical or radiological features of cirrhosis or portal hypertension (AUC 0.87 +/- 0.04).

CONCLUSION

Transient elastography accurately identified compensated cirrhosis; a liver stiffness of >12 kPa represents an important clinical measurement for the diagnosis of cirrhosis.

Thyroid hormone-related regulation of gene expression in human fatty liver

CONTEXT

Fatty liver is an important complication of obesity; however, regulatory mechanisms mediating altered gene expression patterns have not been identified.

OBJECTIVE

The aim of the study was to identify novel transcriptional changes in human liver that could contribute to hepatic lipid accumulation and associated insulin resistance, type 2 diabetes, and nonalcoholic steatohepatitis.

DESIGN

We evaluated gene expression in surgical liver biopsies from 13 obese (nine with type 2 diabetes) and five control subjects using Affymetrix U133A microarrays. PCR validation was performed in liver biopsies using an additional 16 subjects. We also tested thyroid hormone responses in mice fed chow or high-fat diet.

SETTING

Recruitment was performed in an academic medical center.

PARTICIPANTS

Individuals undergoing elective surgery for obesity or gallstones participated in the study.

RESULTS

The top-ranking gene set, down-regulated in obese subjects, was comprised of genes previously demonstrated to be positively regulated by T(3) in human skeletal muscle (n = 399; P < 0.001; false discovery rate = 0.07). This gene set included genes related to RNA metabolism (SNRPE, HNRPH3, TIA1, and SFRS2), protein catabolism (PSMA1, PSMD12, USP9X, IBE2B, USP16, and PCMT1), and energy metabolism (ATP5C1, COX7C, UQCRB). We verified thyroid hormone regulation of these genes in the liver after injection of C57BL/6J mice with T(3) (100 microg/100 g body weight); furthermore, T(3)-induced increases in expression of these genes were abolished by high-fat diet. In agreement, expression of these genes inversely correlated with liver fat content in humans.

CONCLUSIONS

These data suggest that impaired thyroid hormone action may contribute to altered patterns of gene expression in fatty liver.

Validation of hepascore, compared with simple indices of fibrosis, in patients with chronic hepatitis C virus infection in United States

BACKGROUND & AIMS

Biomarkers are being developed as alternatives to liver biopsy for predicting liver fibrosis in patients with chronic hepatitis C. Hepascore uses noninvasive serum markers and has been validated in Australian and European populations for predicting different degrees of fibrosis. This study validated this test in a U.S. population.

METHODS

Patients with chronic hepatitis C virus infection were assigned to training (n = 203) or validation (n = 188) sets. Liver fibrosis was staged according to the METAVIR scoring system. The Hepascore algorithm uses data on age, sex, as well as total bilirubin, gamma-glutamyl transferase, alpha2-macroglobulin, and hyaluronic acid levels.

RESULTS

The ability of Hepascore to predict significant fibrosis (F2-4) as determined by the area under the receiver operating curve was similar in training (0.83) and validation sets (0.81) and was comparable to results seen in previous studies. A cutoff score of > or =0.55 was best for predicting significant fibrosis, with a sensitivity and specificity of 82% and 65% and positive and negative predictive values of 70% and 78%. When compared with 2 simple indices, FIB-4 (age, platelets, AST, and ALT) and APRI (AST/platelet ratio index), Hepascore performed better at excluding advanced fibrosis by using a low cutoff score but worse at predicting fibrosis by using a high cutoff score. An algorithm with Hepascore followed by FIB-4 or APRI spared 103 of 391 individuals a liver biopsy and missed advanced fibrosis in only 1 patient.

CONCLUSIONS

Hepascore accurately predicted likelihood of developing fibrosis and could alleviate the need for liver biopsy in a subset of patients.

The clinical utility of biomarkers and the nonalcoholic steatohepatitis CRN liver biopsy scoring system in patients with nonalcoholic fatty liver disease

BACKGROUND AND AIMS

We identified patients with nonalcoholic fatty liver disease (NAFLD) to determine the predictive value of serum markers to diagnose histological steatohepatitis (NASH).

METHODS

Demographic, serological, radiological and histological variables on 95 consecutive patients with NAFLD were recorded. The serum markers studied were CK18, Hyaluronic acid, TIMP 1 and YKL 40. The NAS score and the metavir score were the histological scoring systems used.

RESULTS

CK18 levels were higher in the NASH group compared to the simple steatosis group (394 +/- 53 micro/L vs 194 +/- 26 micro/L; P < 0.05). In assessing clinical effectiveness, CK18 yielded an AUC of 0.8 for NASH (cut-off value 300 micro/L gives PPV 81% and NPV 85%).The fibrosis markers showed no differences between groups. We stratified the same cohort according to liver fibrosis (F0 vs F1-F4). Fibrosis was associated with advanced age, high body mass index and type 2 diabetes. The biomarkers performed relatively poorly at identifying liver fibrosis (F1-F4), with HA performing the best (AUC 0.73); performance improved for advanced fibrosis (F3/F4) - (HA: AUC 0.77). The NAS score performed the best overall at identifying liver fibrosis (AUC 0.79).

DISCUSSION

CK18 is the only biomarker studied that can identify NASH. Additionally, liver biopsy should be performed in all high risk patients to determine the standardised NAS score to identify patients at high risk of disease progression.

The clinical significance of persistently normal ALT in chronic hepatitis B infection

BACKGROUND/AIMS

Chronic hepatitis B virus (HBV) disease is caused by both necroinflammation and active viral replication. The role of ALT levels as a predictor of liver injury has recently been questioned. The aim of the study was to determine whether normal ALT is associated with liver injury in a cohort of HBV patients undergoing liver biopsy.

METHODS

This is a retrospective review of chronic HBV patients divided into 3 groups; (1) persistently normal ALT (PNALT); (2) ALT 1-1.5X ULN and (3) ALT>1.5X ULN. Multiple clinical, biochemical, virological variables were evaluated.

RESULTS

One hundred and ninety-two patients met the inclusion criteria, 59 with PNALT, 26 with ALT 1-1.5X ULN, and 107 with ALT>1.5X ULN. Increasing age, higher ALT, higher grade of inflammation on biopsy, and HBeAg positivity predicted fibrosis. 18% of patients with PNALT had stage 2+ fibrosis and 34% had grade 2 or 3 inflammation. Overall 37% of patients with PNALT had significant fibrosis or inflammation. Subgroup analysis showed the majority with fibrosis belonged to the high normal ALT group and that only a minority who were young and immune tolerant had significant findings on biopsy.

CONCLUSIONS

There is significant fibrosis and inflammation in 37% of patients with PNALT and a liver biopsy should be considered in patients older than 40 with high normal ALT.

Liver biopsy interpretation for causes of late liver allograft dysfunction

Evaluation of needle biopsies and extensive clinicopathological correlation play an important role in the determination of liver allograft dysfunction occurring more than 1 year after transplantation. Interpretation of these biopsies can be quite difficult because of the high incidence of recurrent diseases that show histopathological, clinical, and serological features that overlap with each other and with rejection. Also, more than one insult can contribute to allograft injury. In an attempt to enable centers to compare and pool results, improve therapy, and better understand pathophysiological disease mechanisms, the Banff Working Group on Liver Allograft Pathology herein proposes a set of consensus criteria for the most common and problematic causes of late liver allograft dysfunction, including late-onset acute and chronic rejection, recurrent and new-onset viral and autoimmune hepatitis, biliary strictures, and recurrent primary biliary cirrhosis and primary sclerosing cholangitis. A discussion of differential diagnosis is also presented.

Microcoil Embolization for Acute Lower Gastrointestinal Bleeding

PURPOSE

To assess outcomes after microcoil embolization for active lower gastrointestinal (GI) bleeding.

METHODS

We retrospectively studied all consecutive patients in whom microcoil embolization was attempted to treat acute lower GI bleeding over 88 months. Baseline, procedural, and outcome parameters were recorded following current Society of Interventional Radiology guidelines. Outcomes included technical success, clinical success (rebleeding within 30 days), delayed rebleeding (>30 days), and major and minor complication rates. Follow-up consisted of clinical, endoscopic, and pathologic data.

RESULTS

Nineteen patients (13 men, 6 women; mean age +/- 95% confidence interval = 70 +/- 6 years) requiring blood transfusion (10 +/- 3 units) had angiography-proven bleeding distal to the marginal artery. Main comorbidities were malignancy (42%), coagulopathy (28%), and renal failure (26%). Bleeding was located in the small bowel (n = 5), colon (n = 13) or rectum (n = 1). Technical success was obtained in 17 patients (89%); 2 patients could not be embolized due to vessel tortuosity and stenoses. Clinical follow-up length was 145 +/- 75 days. Clinical success was complete in 13 (68%), partial in 3 (16%), and failed in 2 patients (11%). Delayed rebleeding (3 patients, 27%) was always due to a different lesion in another bowel segment (0 late rebleeding in embolized area). Two patients experienced colonic ischemia (11%) and underwent uneventful colectomy. Two minor complications were noted.

CONCLUSION

Microcoil embolization for active lower GI bleeding is safe and effective in most patients, with high technical and clinical success rates, no procedure-related mortality, and a low risk of bowel ischemia and late rebleeding.

Angiotensin receptor blockade with candesartan attenuates atherosclerosis, plaque disruption, and macrophage accumulation within the plaque in a rabbit model

BACKGROUND

Little is known about whether direct angiotensin receptor blockade can reduce atherosclerosis and plaque disruption. This study evaluated the effect of angiotensin receptor blockade on both the development of atherosclerosis and the disruption of plaque in a modified Constantinides animal model.

METHODS AND RESULTS

Twenty-eight New Zealand White rabbits underwent aortic balloon injury followed by a 1% cholesterol diet for 8 weeks. Thirteen rabbits received candesartan at 0.5 mg x kg(-1) x d(-1) beginning 2 days before aortic balloon injury and continued for the total 8 weeks of the cholesterol diet. The rabbits were then pharmacologically triggered and humanely killed, and their aortas were analyzed. The degree of atherosclerosis was determined by intima-media ratio of the infrarenal portion of the aorta. The frequency of intra-aortic thrombosis, a measure of plaque disruption, and the percentages of macrophage area and collagen-staining area of the plaque were determined. Candesartan-treated rabbits had less atherosclerosis (intima-media infrarenal aorta ratio of 1.18+/-0.08 versus 1.57+/-0.08 [mean+/-SEM] for the placebo group, P<0.001); fewer thrombi (3 of 13 versus 11 of 15; P<0.05); lower percentage area of macrophages to total plaque (18.8+/-2.7% versus 27+/-2.5%, P<0.05); and higher collagen to total plaque area (45+/-3% versus 35+/-2%, P<0.01).

CONCLUSIONS

These results demonstrate that angiotensin receptor blockade attenuates the degree of atherosclerosis and reduces both plaque disruption and macrophage accumulation while increasing collagen deposition in the aortas of this animal model.

Hepatic CD1d Expression in Hepatitis C Virus Infection and Recognition by Resident Proinflammatory CD1d-Reactive T Cells

A subset of CD161(+)CD56(+/-) NKT cells can recognize glycolipids presented by CD1d and positively or negatively regulate inflammatory responses, including those implicated in several models of hepatitis. CD1d is expressed at very low levels in the healthy liver, but there is a large fraction of CD161(+)CD56(+) NKT cells. There are high levels of nonclassical proinflammatory hepatic CD1d-reactive T cells in hepatitis C virus (HCV) infection. Hepatic inflammatory cells and biliary cells adjacent to portal tract fibrotic areas of HCV-infected donors specifically up-regulated CD1d. A hepatocyte cell line expressing minimal CD1d was efficiently recognized by hepatic CD1d-reactive T cells, suggesting a role for these cells in disease. Hepatic CD1d-reactive T cells from HCV-positive as well as negative donors produced large amounts of IFN-gamma with some IL-13, but only rarely detectable IL-4. We confirmed large numbers of hepatic CD161(+) T cells, lower levels of CD56(+) T cells, and small numbers of classic invariant NKT cells. However, hepatic CD1d-reactivity was not restricted to any of these populations. We suggest virally infected hepatic cells can process potent CD1d-presented liver Ag(s), for surveillance by resident Th1 hepatic CD1d-reactive T cells. This process may be beneficial in acute viral clearance, but in chronic infection could contribute to liver injury.

Crohn's Disease of the Esophagus

Crohn's disease of the esophagus is rare but is being detected more frequently because of the use of upper endoscopy. Clinicopathologic correlation is required to establish the correct diagnosis. We present a case of esophageal Crohn's disease and review the literature to demonstrate that esophageal involvement is usually associated with disease elsewhere in the gut.

Crohn's disease of the esophagus

Crohn's disease of the esophagus is rare but is being detected more frequently because of the use of upper endoscopy. Clinicopathologic correlation is required to establish the correct diagnosis. We present a case of esophageal Crohn's disease and review the literature to demonstrate that esophageal involvement is usually associated with disease elsewhere in the gut.

Cytomorphology of verrucous carcinoma of the cervix. A case report

BACKGROUND

Verrucous carcinoma of the uterine cervix is rare. Cytology is thought not to be helpful in the diagnosis of this lesion due to its bland morphology. The cytologic features of this lesion remain poorly defined.

CASE

The cytologic findings in a Pap smear facilitated the diagnosis of verrucous carcinoma of the cervix. The features included atypical polygonal and spindle cells with abundant, keratinizing cytoplasm; atypical squamous cells with pearl formation; and frequent, nonkoilocytic cytoplasmic vacuolization.

CONCLUSION

There are 30 published reports on verrucous carcinoma involving the cervix and vagina that include the cytologic findings. In 70% of these cases, cytology was abnormal. Recognition of the cytologic characteristics may help in identifying this lesion on cytology, prevent delays in diagnosis and ensure that patients receive appropriate therapy.

Colorectal neoplasms: role of intravenous contrast-enhanced CT colonography

PURPOSE

To evaluate whether computed tomographic (CT) colonography with intravenously administered contrast material can help predict malignant differentiation of colorectal neoplasms (> or =10 mm in diameter).

MATERIALS AND METHODS

Enhancement of 29 consecutive colorectal neoplasms on pre- and postcontrast CT colonographic images was retrospectively measured. The neoplasms were subsequently resected. Enhancement was calculated by subtraction of attenuation values (in Hounsfield units) obtained with precontrast and postcontrast 45-second-delay prone CT colonographic sequences. The neoplasms were graded as follows: grade 1, adenoma; grade 2, adenoma with high-grade dysplasia; grade 3, well-differentiated adenocarcinoma; grade 4, moderately differentiated adenocarcinoma; and grade 5, poorly differentiated adenocarcinoma. Correlation among size, histologic grade, and degree of enhancement was made with Pearson and Spearman coefficients. The ability of the degree of enhancement to help predict adenocarcinoma (histologic grade, > or =3) was calculated.

RESULTS

Histologic-CT colonographic correlation was performed in 29 neoplasms (mean diameter, 27.9 mm; range, 10-65 mm). There was no correlation between size and degree of enhancement, size and histologic grade (R = -0.17, P =.33), or histologic grade and degree of enhancement (R = 0.23, P =.23). However, increasing enhancement was noted between grades 2 and 5. When an enhancement threshold of 40 HU was used for the diagnosis of adenocarcinoma (grades 3-5), sensitivity was 92%, specificity was 20%, positive predictive value was 50%, and negative predictive value was 75%.

CONCLUSION

The degree of contrast enhancement on a 45-second-delay CT colonographic image does not correlate with size or degree of histologic differentiation, although increasing enhancement with lesser degrees of differentiation was noted.

Black esophagus

Black esophagus is a rare, relatively newly described, and usually incidental finding. The differential diagnosis includes several disease states, including ischemia, which has been implicated in acute necrotizing esophagitis. Several theories have been proposed to explain its etiology.

Black Esophagus

Black esophagus is a rare, relatively newly described, and usually incidental finding. The differential diagnosis includes several disease states, including ischemia, which has been implicated in acute necrotizing esophagitis. Several theories have been proposed to explain its etiology.

Hepatic colon cancer metastases in mice: dynamic in vivo correlation with hypoechoic rims visible at US

PURPOSE

To use videomicroscopy of tumor-bearing livers of live mice to depict tumors directly to determine the exact nature of rims seen on corresponding ultrasonographic (US) scans.

MATERIALS AND METHODS

Seventy-six hepatic colorectal cancer metastases were studied in exteriorized livers of 18 mice by using intravital microscopy, US, and histologic examination of the same tumors.

RESULTS

Hypoechoic rims correlated with distended sinusoidal spaces in vivo. These spaces surrounded only locally invasive tumors (mean diameter, 0.85 mm) that had obstructed the supplying terminal portal venules. These spaces, containing adherent leukocytes and tumor cells, gave rise to new tumor vasculature. Results of histologic examination of rims (portal inflammation, congested or compressed sinusoids, cell atrophy) correlated with leukocyte endothelial adherence, occluded sinusoids, and new vessel formation in vivo.

CONCLUSION

Unlike results from previous studies, dynamic in vivo observations of peritumoral rims demonstrated distended sinusoidal spaces giving rise to new tumor-penetrating vessels. These sinusoids arose around locally invasive tumors and were associated with more advanced intrahepatic disease. These dynamic observations provide a pathophysiologic explanation for previous histologic correlates of peritumoral rims.