Intrahepatic Transcriptomics Differentiate Advanced Fibrosis and Clinical Outcomes in Adults With Fontan Circulation

BACKGROUND

The molecular mechanisms underlying Fontan-associated liver disease (FALD) remain largely unknown.

OBJECTIVES

This study aimed to assess intrahepatic transcriptomic differences among patients with FALD according to the degree of liver fibrosis and clinical outcomes.

METHODS

This retrospective cohort study included adults with the Fontan circulation. Baseline clinical, laboratory, imaging, and hemodynamic data as well as a composite clinical outcome (CCO) were extracted from medical records. Patients were classified into early or advanced fibrosis. RNA was isolated from formalin-fixed paraffin-embedded liver biopsy samples; RNA libraries were constructed with the use of an rRNA depletion method and sequenced on an Illumina Novaseq 6000. Differential gene expression and gene ontology analyses were performed with the use of DESeq2 and Metascape.

RESULTS

A total of 106 patients (48% male, median age 31 years [IQR: 11.3 years]) were included. Those with advanced fibrosis had higher B-type natriuretic peptide levels and Fontan, mean pulmonary artery, and capillary wedge pressures. The CCO was present in 23 patients (22%) and was not predicted by advanced liver fibrosis, right ventricular morphology, presence of aortopulmonary collaterals, or Fontan pressures on multivariable analysis. Samples with advanced fibrosis had 228 upregulated genes compared with early fibrosis. Samples with the CCO had 894 upregulated genes compared with those without the CCO. A total of 136 upregulated genes were identified in both comparisons and were enriched in cellular response to cytokine stimulus or oxidative stress, VEGFA-VEGFR2 signaling pathway, TGF-β signaling pathway, and vasculature development.

CONCLUSIONS

Patients with FALD and advanced fibrosis or the CCO exhibited upregulated genes related to inflammation, congestion, and angiogenesis.

Myeloid spatial and transcriptional molecular signature of ischemia-reperfusion injury in human liver transplantation

BACKGROUND

Ischemia-reperfusion injury (IRI) is a significant clinical concern in liver transplantation, with a key influence on short-term and long-term allograft and patient survival. Myeloid cells trigger and sustain tissue inflammation and damage associated with IRI, but the mechanisms regulating these activities are unknown. To address this, we investigated the molecular characteristics of intragraft myeloid cells present in biopsy-proven IRI- and IRI+ liver transplants.

METHODS

RNA-sequencing was performed on 80 pre-reperfusion and post-reperfusion biopsies from 40 human recipients of liver transplantation (23 IRI+, 17 IRI-). We used transcriptional profiling and computational approaches to identify specific gene coexpression network modules correlated with functional subsets of MPO+, lysozyme+, and CD68+ myeloid cells quantified by immunohistochemistry on sequential sections from the same patient biopsies.

RESULTS

A global molecular map showed gene signatures related to myeloid activation in all patients regardless of IRI status; however, myeloid cell subsets differed dramatically in their spatial morphology and associated gene signatures. IRI- recipients were found to have a natural corticosteroid production and response profile from pre-reperfusion to post-reperfusion, particularly among monocytes/macrophages. The pre-reperfusion signature of IRI+ recipients included acute inflammatory responses in neutrophils and increased translation of adaptive immune-related genes in monocytes/macrophages coupled with decreased glucocorticoid responses. Subsequent lymphocyte activation at post-reperfusion identified transcriptional programs associated with the transition to adaptive immunity found only among IRI+ recipients.

CONCLUSIONS

Myeloid subset-specific genes and related signaling pathways provide targets for the development of therapeutic strategies aimed at limiting IRI in the clinical setting of liver transplantation.

Disulfide-HMGB1 signals through TLR4 and TLR9 to induce inflammatory macrophages capable of innate-adaptive crosstalk in human liver transplantation

Ischemia-reperfusion injury (IRI) during orthotopic liver transplantation (OLT) contributes to graft rejection and poor clinical outcomes. The disulfide form of high mobility group box 1 (diS-HMGB1), an intracellular protein released during OLT-IRI, induces pro-inflammatory macrophages. How diS-HMGB1 differentiates human monocytes into macrophages capable of activating adaptive immunity remains unknown. We investigated if diS-HMGB1 binds toll-like receptor (TLR) 4 and TLR9 to differentiate monocytes into pro-inflammatory macrophages that activate adaptive immunity and promote graft injury and dysfunction. Assessment of 106 clinical liver tissue and longitudinal blood samples revealed that OLT recipients were more likely to experience IRI and graft dysfunction with increased diS-HMGB1 released during reperfusion. Increased diS-HMGB1 concentration also correlated with TLR4/TLR9 activation, polarization of monocytes into pro-inflammatory macrophages, and production of anti-donor antibodies. In vitro, healthy volunteer monocytes stimulated with purified diS-HMGB1 had increased inflammatory cytokine secretion, antigen presentation machinery, and reactive oxygen species production. TLR4 inhibition primarily impeded cytokine/chemokine and costimulatory molecule programs, whereas TLR9 inhibition decreased HLA-DR and reactive oxygen species production. diS-HMGB1-polarized macrophages also showed increased capacity to present antigens and activate T memory cells. In murine OLT, diS-HMGB1 treatment potentiated ischemia-reperfusion-mediated hepatocellular injury, accompanied by increased serum alanine transaminase levels. This translational study identifies the diS-HMGB1/TLR4/TLR9 axis as potential therapeutic targets in OLT-IRI recipients.

Immune Features of Disparate Liver Transplant Outcomes in Female Hispanics With Nonalcoholic Steatohepatitis

Background

Nonalcoholic steatohepatitis (NASH) is a severe immune-mediated stage of nonalcoholic fatty liver disease that is rapidly becoming the most common etiology requiring liver transplantation (LT), with Hispanics bearing a disproportionate burden. This study aimed to uncover the underlying immune mechanisms of the disparities experienced by Hispanic patients undergoing LT for NASH.

Methods

We enrolled 164 LT recipients in our institutional review board-approved study, 33 of whom presented with NASH as the primary etiology of LT (20%), with 16 self-reported as Hispanic (48%). We investigated the histopathology of prereperfusion and postreperfusion biopsies, clinical liver function tests, longitudinal soluble cytokines via 38-plex Luminex, and immune cell phenotypes generated by prereperfusion and postreperfusion blood using 14-color flow cytometry and enzyme-linked immunosorbent assay.

Results

Hispanic LT recipients transplanted for NASH were disproportionately female (81%) and disproportionately suffered poor outcomes in the first year posttransplant, including rejection (26%) and death (38%). Clinically, we observed increased pro-inflammatory and apoptotic histopathological features in biopsies, increased AST/international normalized ratio early posttransplantation, and a higher incidence of presensitization to mismatched HLA antigens expressed by the donor allograft. Experimental investigations revealed that blood from female Hispanic NASH patients showed significantly increased levels of leukocyte-attracting chemokines, innate-to-adaptive switching cytokines and growth factors, HMGB1 release, and TLR4/TLR8/TLR9/NOD1 activation, and produced a pro-inflammatory, pro-apoptotic macrophage phenotype with reduced CD14/CD68/CD66a/TIM-3 and increased CD16/CD11b/HLA-DR/CD80.

Conclusions

A personalized approach to reducing immunological risk factors is urgently needed for this endotype in Hispanics with NASH requiring LT, particularly in females.

This is Jeopardy! A flexible coverage-based schedule model to address wellness for pathology training programs

Scheduling rotations for a pathology training program involves balancing educational requirements, service coverage, and paid time off (PTO). Absences can affect training as residents cross-cover, managing multiple services at once. Other specialties utilize a "Jeopardy" based system for covering absences. In this system, residents on outpatient services are "jeopardized" to cover inpatient services for trainee absences. Borrowing this concept, we created a schedule model with a "Jeopardy-Elective" (JE) rotation to support resident absences. Prior to 2018-19, our residency program consisted of a 12 month-long rotation schedule. We adopted a 13 four-week block rotation model system, adding four JE rotations per resident over the course of training. The JE resident covered services during trainee absences and spent the remaining rotation on elective. We then conducted a pre- and post-intervention survey of all residents who trained in both systems. Following the change in schedule model, our results showed a statistically significant increase in resident satisfaction with taking PTO (p = 0.0014), finding coverage (p = 0.0006), and taking a sick day (p = 0.03). The mean number of days covered by the JE resident was 8.5 ± 2.7 workdays (out of 20). PTO usage increased from 16 to 20 days/resident while mean number of sick days decreased from 1.7 to 1.3 days per resident. There was overwhelming support with 82% of residents wanting to retain the new system going forward. Through use of the JE rotation, our program improved service coverage issues and resident satisfaction, with the long-term goal of enhanced resident well-being and enriched resident learning experiences.

Intrahepatic transcriptomics differentiate advanced fibrosis and clinical outcomes in adults with the Fontan circulation

Background

The molecular mechanisms underlying Fontan associated liver disease (FALD) remain largely unknown. We aimed to assess intrahepatic transcriptomic differences among patients with FALD according to the degree of liver fibrosis and clinical outcomes.

Methods

This retrospective cohort study included adults with the Fontan circulation at the Ahmanson/UCLA Adult Congenital Heart Disease Center. Clinical, laboratory, imaging and hemodynamic data prior to the liver biopsy were extracted from medical records. Patients were classified into early (F1-F2) or advanced fibrosis (F3-F4). RNA was isolated from formalin-fixed paraffin embedded liver biopsy samples; RNA libraries were constructed using rRNA depletion method and sequencing was performed on Illumina Novaseq 6000. Differential gene expression and gene ontology analyses were carried out using DESeq2 and Metascape. Medical records were comprehensively reviewed for a composite clinical outcome which included decompensated cirrhosis, hepatocellular carcinoma, liver transplantation, protein-losing enteropathy, chronic kidney disease stage 4 or higher, or death.

Results

Patients with advanced fibrosis had higher serum BNP levels and Fontan, mean pulmonary artery and capillary wedge pressures. The composite clinical outcome was present in 23 patients (22%) and was predicted by age at Fontan, right ventricular morphology and presence of aortopulmonary collaterals on multivariable analysis. Samples with advanced fibrosis had 228 up-regulated genes compared to early fibrosis. Samples with the composite clinical outcome had 894 up-regulated genes compared to those without it. A total of 136 up-regulated genes were identified in both comparisons and these genes were enriched in cellular response to cytokine stimulus, response to oxidative stress, VEGFA-VEGFR2 signaling pathway, TGF-beta signaling pathway, and vasculature development.

Conclusions

Patients with FALD and advanced liver fibrosis or the composite clinical outcome exhibit up-regulated genes including pathways related to inflammation, congestion, and angiogenesis. This adds further insight into FALD pathophysiology.

Correlation of Computed Tomography, Pathological Findings, and Clinical Outcomes for Appendicoliths in Appendicitis

Objectives

To correlate preoperative imaging of fecaliths with what is seen in surgical specimens.

Background

Early studies considered radiological findings of appendicoliths as a contraindication for nonoperative treatment of appendicitis. There is no standard definition for what is labeled as an appendicolith radiologically and little is known about the pathological correlates of these lesions.

Methods

A single center, retrospective study of a consecutive series of adult patients who underwent appendectomy for acute appendicitis from March 2021 to February 2022 was performed. The primary outcome was concordance between preoperative cross-sectional imaging description of appendicolith with postoperative gross pathology description. Images were retrospectively reviewed by an independent radiologist, and the presence and characteristics of appendicoliths and appendices were examined.

Results

Of 88 cases of appendicitis, 86 were diagnosed preoperatively by computed tomography (CT) imaging. Appendicoliths were seen either on CT or pathology in 45 (51%) patients. Of these 45 patients, a total of 38 (84%) were identified radiographically, and 28 (62%) were identified on pathology. Of the 38 appendicoliths diagnosed on preoperative imaging, only 21 (55%) were confirmed pathologically. Additionally, of the 28 appendicoliths observed on pathology, only 21 (75%) were identified preoperatively on imaging. There was no appendiceal obstruction in 10 of the 40 cases (25%) in which retrospective radiological review identified appendicoliths.

Conclusions

Discrepancies were observed between CT and pathology findings of appendicoliths. Not all appendicoliths seem to cause appendicitis. Because the presence of appendicolith influences the treatment decisions, there is a need to standardize their radiological diagnosis and better understand their pathophysiology.

Hepatocellular Adenoma Subtypes Based on 2017 Classification System: Exploratory Study of Gadoxetate Disodium-Enhanced MRI Features With Proposal of a Diagnostic Algorithm

BACKGROUND. The classification of hepatocellular adenomas (HCAs) was updated in 2017 on the basis of genetic and molecular analysis. OBJECTIVE. The purpose of this article was to evaluate features on gadoxetate disodium-enhanced MRI of HCA subtypes on the basis of the 2017 classification and to propose a diagnostic algorithm for determining subtype using these features. METHODS. This retrospective study included 56 patients (49 women, seven men; mean age, 37 ± 13 [SD] years) with histologically confirmed HCA evaluated by gadoxetate disodium-enhanced MRI from January 2010 to January 2021. Subtypes were reclassified using 2017 criteria: hepatocyte nuclear factor-1α mutated HCA (HHCA), inflammatory HCA (IHCA), β-catenin exon 3 activated HCA (β-HCA), mixed inflammatory and β-HCA (β-IHCA), sonic hedgehog HCA (shHCA), and unclassified HCA (UHCA). Qualitative MRI features were assessed. Liver-to-lesion contrast enhancement ratios (LLCERs) were measured. Subtypes were compared, and a diagnostic algorithm was proposed. RESULTS. The analysis included 65 HCAs: 16 HHCAs, 31 IHCAs, six β-HCA, four β-IHCA, five shHCA, and three UHCAs. HHCAs showed homogeneous diffuse intralesional steatosis in 94%, whereas all other HCAs showed this finding in 0% (p < .001). IHCAs showed the "atoll" sign in 58%, whereas all other HCAs showed this finding in 12% (p < .001). IHCAs showed moderate T2 hyperintensity in 52%, whereas all other HCAs showed this finding in 12% (p < .001). The β-HCAs and β-IHCAs occurred in men in 63%, whereas all other HCAs occurred in men in 4% (p < .001). The β-HCAs and β-IHCAs had a mean size of 10.1 ± 6.8 cm, whereas all other HCAs had a mean size of 5.1 ± 2.9 cm (p = .03). The β-HCAs and β-IHCAs showed fluid components in 60%, whereas all other HCAs showed this finding in 5% (p < .001). Hepatobiliary phase iso- or hyperintensity was observed in 80% of β-HCAs and β-IHCAs versus 5% of all other HCAs (p < .001). Hepatobiliary phase LLCER was positive in nine HCAs (eight β-HCAs and β-IHCAs; one IHCA). The shHCA and UHCA did not show distinguishing features. The proposed diagnostic algorithm had accuracy of 98% for HHCAs, 83% for IHCAs, and 95% for β-HCAs or β-IHCAs. CONCLUSION. Findings on gadoxetate disodium-enhanced MRI, including hepatobiliary phase characteristics, were associated with HCA subtypes using the 2017 classification. CLINICAL IMPACT. The algorithm identified common HCA subtypes with high accuracy, including those with β-catenin exon 3 mutations.

Hepatocellular Adenomas: Molecular Basis and Multimodality Imaging Update

Hepatocellular adenomas (HCAs) are a family of liver tumors that are associated with variable prognoses. Since the initial description of these tumors, the classification of HCAs has expanded and now includes eight distinct genotypic subtypes based on molecular analysis findings. These genotypic subtypes have unique derangements in their cellular biologic makeup that determine their clinical course and may allow noninvasive identification of certain subtypes. Multiphasic MRI performed with hepatobiliary contrast agents remains the best method to noninvasively detect, characterize, and monitor HCAs. HCAs are generally hypointense during the hepatobiliary phase; the β-catenin-mutated exon 3 subtype and up to a third of inflammatory HCAs are the exception to this characterization. It is important to understand the appearances of HCAs beyond their depictions at MRI, as these tumors are typically identified with other imaging modalities first. The two most feared related complications are bleeding and malignant transformation to hepatocellular carcinoma, although the risk of these complications depends on tumor size, subtype, and clinical factors. Elective surgical resection is recommended for HCAs that are persistently larger than 5 cm, adenomas of any size in men, and all β-catenin-mutated exon 3 HCAs. Thermal ablation and transarterial embolization are potential alternatives to surgical resection. In the acute setting of a ruptured HCA, patients typically undergo transarterial embolization with or without delayed surgical resection. This update on HCAs includes a review of radiologic-pathologic correlations by subtype and imaging modality, related complications, and management recommendations. ^© RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Apheresis of Deceased Donors as a New Source of Mobilized Peripheral Blood Hematopoietic Stem Cells for Transplant Tolerance

BACKGROUND

Solid organ transplantation is the therapy of choice for many patients with end-stage organ failure; however, recipients must remain on lifelong immunosuppression, leaving them susceptible to infections and cancer. The study of transplant tolerance to prolong graft survival in the absence of immunosuppression has been restricted to recipients of living donor allografts; however, deceased donors significantly outnumber living donors. Mobilization of hematopoietic stem cells (HSCs) from the bone marrow to peripheral blood (PB) could allow PB-HSCs to be used to induce tolerance in deceased donor kidney recipients; however, a major concern is the well-known concomitant mobilization of immune cells into the liver.

METHODS

We mobilized HSCs to the PD using a protocol of 2 doses of granulocyte colony-stimulating factor and 1 dose of plerixafor, followed by the collection of mobilized cells via apheresis in 3 deceased donors. The physiological, laboratory, and radiographic parameters were monitored throughout the procedure. Longitudinal biopsies were performed to assess the potential for ectopic liver mobilization.

RESULTS

The use of both agents led to the successful mobilization of peripheral blood CD34+ cells, demonstrating the potential for use in transplant tolerance protocols. Increased immune cell trafficking into the liver was not observed, and apheresis of mobilized cells resulted in a uniform decrease in all liver leukocyte subsets.

CONCLUSIONS

HSCs can be mobilized and collected from the PB of brain-dead donors. This new approach may facilitate the dissemination of immune tolerance trials beyond living-donor kidney transplantation to deceased-donor transplantation, without sacrificing the transplantability of the liver.

Operational tolerance is not always permanent: A 10-year prospective study in pediatric liver transplantation recipients

Immunosuppression withdrawal can be safely performed in select liver transplantation recipients, but the long-term outcomes and sustainability of tolerance have not been well studied. We completed a 10-year prospective, observational study of 18 pediatric liver transplantation recipients with operational tolerance to (1) assess the sustainability of tolerance over time, (2) compare the clinical characteristics of patients who maintained versus lost tolerance, (3) characterize liver histopathology findings in surveillance liver biopsies; and (4) describe immunologic markers in patients with tolerance. Comparator patients from two clinical phenotype groups termed "stable" and "nontolerant" patients were used as controls. Of the 18 patients with operational tolerance, the majority of patients were males (n = 14, 78%) who were transplanted for cholestatic liver disease (n = 12, 67%). Median age at transplantation was 1.9 (range, 0.6-8) years. Median time after transplantation that immunosuppression had been discontinued was 13.1 (range, 2.9-22.1) years. As many as 11 (61%) maintained tolerance for a median of 10.4 (range, 1.9-22.1) years, whereas 7 (39%) lost tolerance after a median of 3.2 (range, 1.5-18.6) years. Populations of T regulatory cells (%CD4⁺ CD25^hi CD127^lo ) were significantly higher in patients with tolerance (p = 0.02). Our results emphasize that spontaneous operational tolerance is a dynamic and nonpermanent state. It is therefore essential for patients who are clinically stable off immunosuppression to undergo regular follow-up and laboratory monitoring, as well as surveillance biopsies to rule out subclinical rejection.

Cytomegalovirus Hepatitis in Allograft Livers May Show Histologic Features of Acute Cellular Rejection

CONTEXT.—

Cytomegalovirus (CMV) hepatitis in allograft livers is an important infectious complication, with histology that historically has been described to overlap with that of acute cellular rejection (ACR), a diagnosis that compels a different treatment regimen.

OBJECTIVE.—

To update the clinicopathologic features of CMV hepatitis and explore its clinical and histologic relationship with ACR.

DESIGN.—

A retrospective analysis of 26 patients with a diagnosis of CMV hepatitis across 4 institutions was performed, including clinical, histologic, and immunohistochemical features.

RESULTS.—

Patients were predominantly CMV donor positive/recipient negative (D+/R-; n = 9 of 15) and received a diagnosis of CMV hepatitis at a mean age of 52 years (SD, 17 years), at a mean interval of 184 days (SD, 165 days) from transplantation. Mean CMV viral load at diagnosis was 241 000 IU/mL (SD, 516 000 IU/mL), and liver biochemical enzymes were elevated (mean alanine aminotransferase, 212 U/L [SD, 180 U/L]; mean aspartate aminotransferase, 188 U/L [SD, 151 U/L]; mean alkaline phosphatase, 222 U/L [SD, 153 U/L]). Ten cases did not show histologic features of ACR, and 16 cases demonstrated features of ACR (including marked bile duct injury and endotheliitis). Viral cytopathic change was found in all cases. All patients were treated with a combination of antiviral therapy and CMV intravenous immunoglobulin, with near resolution of biochemical enzymes in all patients with undetectable serum CMV viral titers.

CONCLUSIONS.—

CMV hepatitis and ACR are complex processes with interlinking mechanisms that are important to distinguish. A subset of transplantation patients with CMV hepatitis show histologic changes that mimic ACR but were treated successfully with antiviral therapy alone.

BRAF Rearrangements and BRAF V600E Mutations Are Seen in a Subset of Pancreatic Carcinomas With Acinar Differentiation

CONTEXT.—

Comprehensive genomic profiling has demonstrated that approximately 20% of pancreatic carcinomas with acinar differentiation harbor potentially targetable BRAF fusions that activate the MAPK pathway.

OBJECTIVES.—

To validate the above finding by BRAF break-apart fluorescence in situ hybridization (FISH) in a large series of pure acinar cell carcinomas (ACCs), evaluate tumors for the presence of BRAF V600E mutations, and compare clinicopathologic features of tumors with BRAF rearrangements with those without.

DESIGN.—

Thirty cases of pure ACC and 6 cases of mixed acinar-neuroendocrine carcinoma (ACC-NEC) were retrieved. A break-apart FISH probe was used to detect BRAF rearrangements. Immunohistochemistry for BRAF V600E was performed.

RESULTS.—

BRAF rearrangements by FISH were found in 6 of 36 cases (17%), 5 of which were pure ACC and 1 was a mixed ACC-NEC. Follow-up was available in 29 of 36 cases (81%). The median survival was 22 months for BRAF-rearranged cases and 16 months for BRAF-intact cases; the 2-year overall survival was 50% for BRAF-rearranged cases and 35% for BRAF-intact cases. No significant clinicopathologic differences were identified in cases with BRAF rearrangement compared with those without BRAF rearrangement. BRAF V600E mutation was identified in 2 of 34 cases (6%), both of which were pure ACC and were BRAF-intact by FISH.

CONCLUSIONS.—

This study supports the finding that BRAF rearrangements are present in approximately 20% of cases and identified BRAF V600E mutations in approximately 5% of cases. These cases may benefit from targeted therapy.

IgG4-related hypertensive granulomatous anterior uveitis

Purpose

To report a case of hypertensive granulomatous anterior uveitis in the setting of IgG4-related disease (IgG4-RD).

Observations

A 69-year-old man presented with no light perception vision in both eyes and bilateral granulomatous anterior uveitis with iris neovascularization and hyphema in the right eye. He also demonstrated concurrent polyuria, polydipsia, and altered mental status, and was diagnosed with new-onset diabetes mellitus. MRI revealed no orbital abnormalities, but showed bilateral occipital strokes attributed to hyperglycemic hyperosmolar syndrome. Chest CT revealed pleural-based nodules and mediastinal and abdominal lymphadenopathy, and a liver biopsy confirmed fibroinflammatory nodules with increased IgG4 positive plasma cell infiltrates, diagnostic of IgG4-RD. Serum IgG4 levels were 1381 mg/dL. The patient was treated with a combination of systemic and topical steroids, and later initiated on rituximab.

Conclusion and importance

IgG4-related ophthalmic disease may present as an isolated hypertensive granulomatous anterior uveitis without associated scleral or orbital involvement.

Donor Hepatic Occult Collagen Deposition Predisposes to Peritransplant Stress and Impacts Human Liver Transplantation

BACKGROUND AND AIMS

Environmentally triggered chronic liver inflammation can cause collagen deposits, whereas early stages of fibrosis without any specific symptoms could hardly be detectable. We hypothesized that some of the human donor grafts in clinical liver transplantation (LT) might possess unrecognizable fibrosis, affecting their susceptibility to LT-induced stress and hepatocellular damage. This retrospective study aimed to assess the impact of occult hepatic fibrosis on clinical LT outcomes.

APPROACH AND RESULTS

Human (194) donor liver biopsies were stained for collagen with Sirius red, and positive areas (Sirius red-positive area; SRA) were measured. The body mass index, aspartate aminotransferase/alanine aminotransferase ratio, diabetes score was calculated using 962 cases of the donor data at the procurement. LT outcomes, including ischemia-reperfusion injury (IRI), early allograft dysfunction (EAD), and survival rates, were analyzed according to SRA and BARD scores. With the median SRA in 194 grafts of 9.4%, grafts were classified into low-SRA (<15%; n = 140) and high-SRA (≥15%; n = 54) groups. Grafts with high SRA suffered from higher rates of IRI and EAD (P < 0.05) as compared to those with low SRA. Interestingly, high SRA was identified as an independent risk factor for EAD and positively correlated with the donor BARD score. When comparing low-BARD (n = 692) with high-BARD (n = 270) grafts in the same period, those with high BARD showed significantly higher post-LT transaminase levels and higher rates of IRI and EAD.

CONCLUSIONS

These findings from the largest clinical study cohort to date document the essential role of occult collagen deposition in donor livers on LT outcomes. High-SRA and donor BARD scores correlated with an increased incidence of hepatic IRI and EAD in LT recipients. This study provides the rationale for in-depth and prospective assessment of occult fibrosis for refined personalized LT management.

REG3α is a novel biomarker that potentially correlates with acute allograft rejection after intestinal transplantation

Monitoring of intestinal allograft function remains a challenge. While frequent endoscopies and biopsies are the gold standard, no single biomarker exists to screen for intestinal transplant rejection. The novel REG3α, an antimicrobial peptide secreted by intestinal enterocytes and Paneth cells, has been associated with inflammatory bowel disease as well as intestinal graft versus host disease. Our aim was to identify and describe a role of REG3α in monitoring or predicting acute allograft rejection after intestinal transplantation (ITx). Since 2019, we have incorporated REG3α into the standard monitoring of patients after ITx. We conducted a retrospective analysis of a prospectively maintained IRB-approved database and present, herein, the results of 2 adults with irreversible intestinal failure who underwent isolated ITx under this monitoring protocol. Increases in REG3α corresponded with acute allograft rejection in both cases and preceded acute allograft rejection by 1 week in one of the cases. We describe REG3α as a non-invasive marker of acute allograft rejection after adult isolated ITx which not only corresponded with acute allograft rejection but also preceded histopathological changes by 1 week.

Disulfide High-Mobility Group Box 1 Drives Ischemia-Reperfusion Injury in Human Liver Transplantation

BACKGROUND AND AIMS

Sterile inflammation is a major clinical concern during ischemia-reperfusion injury (IRI) triggered by traumatic events, including stroke, myocardial infarction, and solid organ transplantation. Despite high-mobility group box 1 (HMGB1) clearly being involved in sterile inflammation, its role is controversial because of a paucity of patient-focused research.

APPROACH AND RESULTS

Here, we examined the role of HMGB1 oxidation states in human IRI following liver transplantation. Portal blood immediately following allograft reperfusion (liver flush; LF) had increased total HMGB1, but only LF from patients with histopathological IRI had increased disulfide-HMGB1 and induced Toll-like receptor 4-dependent tumor necrosis factor alpha production by macrophages. Disulfide HMGB1 levels increased concomitantly with IRI severity. IRI+ prereperfusion biopsies contained macrophages with hyperacetylated, lysosomal disulfide-HMGB1 that increased postreperfusion at sites of injury, paralleling increased histone acetyltransferase general transcription factor IIIC subunit 4 and decreased histone deacetylase 5 expression. Purified disulfide-HMGB1 or IRI+ blood stimulated further production of disulfide-HMGB1 and increased proinflammatory molecule and cytokine expression in macrophages through a positive feedback loop.

CONCLUSIONS

These data identify disulfide-HMGB1 as a mechanistic biomarker of, and therapeutic target for, minimizing sterile inflammation during human liver IRI.

Ischemia-reperfusion injury and its relationship with early allograft dysfunction in liver transplant patients

Ischemia-reperfusion injury (IRI) is believed to contribute to graft dysfunction after liver transplantation (LT). However, studies on IRI and the impact of early allograft dysfunction (EAD) in IRI grafts are limited. Histological IRI was graded in 506 grafts from patients who had undergone LT and classified based on IRI severity (no, minimal, mild, moderate, and severe). Of the 506 grafts, 87.4% had IRI (no: 12.6%, minimal: 38.1%, mild: 35.4%, moderate: 13.0%, and severe: 0.8%). IRI severity correlated with the incidence of EAD and graft survival at 6 months. Longer cold/warm ischemia time, recipient/donor hypertension, and having a male donor were identified as independent risk factors for moderate to severe IRI. Among 70 grafts with moderate to severe IRI, 42.9% of grafts developed EAD, and grafts with EAD had significantly inferior survival compared to grafts without EAD. Longer cold ischemia time and large droplet macrovesicular steatosis (≥20%) were identified as independent risk factors for EAD. Our study demonstrated that increased IRI severity was correlated with inferior short-term graft outcomes. Careful consideration of IRI risk factors during donor-recipient matching may assist in optimizing graft utilization and LT outcomes. Furthermore, identification of risk factors of IRI-associated EAD may guide patient management and possible timely graft replacement.

Molecular and Immunohistochemical Analysis of Mucinous Cystic Neoplasm of the Liver

OBJECTIVES

Mucinous cystic neoplasm of the liver is characterized by neoplastic mucinous and/or biliary epithelium surrounded by ovarian-type stroma. Immunohistochemical studies have shown that the ovarian-type stroma expresses estrogen receptor, suggesting potential hormonal responsiveness. The molecular biology of mucinous cystic neoplasm of the liver remains poorly studied.

METHODS

Transcriptome sequencing and immunohistochemistry were performed on a series of mucinous cystic neoplasms.

RESULTS

Mucinous cystic neoplasm of the liver exhibited significantly increased RNA expression of ovarian stromal markers WT1, PR, and ER2 and sex cord stromal markers SF-1, inhibin-α, and calretinin compared with nonneoplastic liver. Immunohistochemistry confirmed the RNA-level data. Evidence for sex hormone biosynthesis was identified by significant overexpression of multiple estrogen biosynthetic enzymes. Expression of 17β-hydroxysteroid dehydrogenase 1 was confirmed immunohistochemically. Pathway analysis also identified significant upregulation of the hedgehog and Wnt pathways and significant downregulation of T-helper 1 and T-helper 2 pathways.

CONCLUSIONS

Mucinous cystic neoplasm of the liver recapitulates ovarian stroma at the morphologic, DNA, RNA, and protein levels. These data support the concept that this tumor likely arises from ectopic primitive gonadal tissue and/or stromal cells with capacity to transdifferentiate to ovarian cortical cells.

Helicobacter pylori infection impairs chaperone-assisted maturation of Na-K-ATPase in gastric epithelium

Helicobacter pylori infection always induces gastritis, which may progress to ulcer disease or cancer. The mechanisms underlying mucosal injury by the bacteria are incompletely understood. Here, we identify a novel pathway for H. pylori-induced gastric injury, the impairment of maturation of the essential transport enzyme and cell adhesion molecule, Na-K-ATPase. Na-K-ATPase comprises α- and β-subunits that assemble in the endoplasmic reticulum (ER) before trafficking to the plasma membrane. Attachment of H. pylori to gastric epithelial cells increased Na-K-ATPase ubiquitylation, decreased its surface and total levels, and impaired ion balance. H. pylori did not alter degradation of plasmalemma-resident Na-K-ATPase subunits or their mRNA levels. Infection decreased association of α- and β-subunits with ER chaperone BiP and impaired assembly of α/β-heterodimers, as was revealed by quantitative mass spectrometry and immunoblotting of immunoprecipitated complexes. The total level of BiP was not altered, and the decrease in interaction with BiP was not observed for other BiP client proteins. The H. pylori-induced decrease in Na-K-ATPase was prevented by BiP overexpression, stopping protein synthesis, or inhibiting proteasomal, but not lysosomal, protein degradation. The results indicate that H. pylori impairs chaperone-assisted maturation of newly made Na-K-ATPase subunits in the ER independently of a generalized ER stress and induces their ubiquitylation and proteasomal degradation. The decrease in Na-K-ATPase levels is also seen in vivo in the stomachs of gerbils and chronically infected children. Further understanding of H. pylori-induced Na-K-ATPase degradation will provide insights for protection against advanced disease.NEW & NOTEWORTHY This work provides evidence that Helicobacter pylori decreases levels of Na-K-ATPase, a vital transport enzyme, in gastric epithelia, both in acutely infected cultured cells and in chronically infected patients and animals. The bacteria interfere with BiP-assisted folding of newly-made Na-K-ATPase subunits in the endoplasmic reticulum, accelerating their ubiquitylation and proteasomal degradation and decreasing efficiency of the assembly of native enzyme. Decreased Na-K-ATPase expression contributes to H. pylori-induced gastric injury.

Something old, something new: liver injury associated with total parenteral nutrition therapy and immune checkpoint inhibitors

Drug-induced liver injury (DILI) is a challenging and constantly changing field. The pathologist plays a key role in interpreting liver biopsies by classifying the pattern of injury, grading the severity of injury, and evaluating for other possible causes. Reports of iatrogenic liver injury are reviewed here with a focus on total parenteral nutrition (ie, intestinal failure-associated liver disease [IFALD]) and immune checkpoint inhibitors (ICIs). The hallmark features of IFALD are cholestasis and steatosis. Cholestasis is more common in infants, whereas steatosis and steatohepatitis are more commonly seen in older children and adults. Infants tend to have a faster progression to fibrosis and cirrhosis. Perivenular fibrosis and ductopenia may also be seen in IFALD. Although fish oil-based lipid emulsions can reverse cholestasis, recent studies have shown persistent or progressive fibrosis. ICI-induced liver injury usually presents as an acute hepatitis with features similar to those seen in idiopathic autoimmune hepatitis and drug-induced autoimmune hepatitis. However, it lacks a prominent plasma cell infiltrate and serological markers of autoimmune hepatitis. Other features such as fibrin ring granulomas and cholangitis have also been reported in association with ICIs. Treatment for ICI-induced liver injury includes corticosteroids and other immunosuppressants.

Identification of key challenges in liver pathology: data from a multicenter study of extramural consults

Extramural consultation for challenging pathology cases is an important part of patient care. The specific reasons why liver cases are submitted in consultation are poorly understood. To study patterns in extramural consultation, data were gathered from 1360 liver/GI/pancreatobiliary consults submitted to 7 academic centers. Liver cases comprised 40% of consults and are the focus of this paper. They were submitted for questions on medical (61%) and tumor pathology (39%). A preliminary diagnosis was provided by the referring pathologist in 65% of cases. The most common questions in medical liver pathology were on general classification of a hepatitic pattern of injury (37%), primary biliary cirrhosis (14%), fatty liver disease (13%), autoimmune hepatitis (12%), and etiology of cirrhosis (10%). Most tumor consults were submitted for classification (83%). The most common final tumor consultant diagnoses for benign tumors were hepatic adenoma or focal nodular hyperplasia (52%) and for malignant tumors were metastatic malignancies (47%), hepatocellular carcinoma (32%), or cholangiocarcinoma (8%). For cases submitted with a diagnosis of malignancy, the diagnosis was concordant (43% of cases), concordant but with a generic diagnosis for which a more specific diagnosis could be rendered (37%), or discordant with a major change in diagnosis from malignant to benign or change in tumor type (17%). In conclusion, analysis of consult patterns identifies challenging areas in medical and tumor liver pathology, areas that benefit from consult services and can be focused on by continuing medical educational activities.

Metabolic factors affecting hepatocellular carcinoma in steatohepatitis

BACKGROUND & AIMS

With the rising prevalence of alcoholism, obesity and metabolic syndrome, steatohepatitis will become the leading cause of end-stage liver disease and hepatocellular carcinoma in the United States by 2025. Patients with non-alcoholic steatohepatitis and alcoholic liver disease have similar clinical and histopathological presentations, whether these similarities persist in non-alcoholic steatohepatitis and alcoholic liver disease patients with hepatocellular carcinoma remains unknown.

METHODS

A retrospective analysis of the clinical features of adult patients from a large transplant center who underwent liver transplantation for steatohepatitis due to non-alcoholic steatohepatitis and alcoholic causes (alcoholic liver disease) between 1/1/02 and 1/1/12 was performed. Clinical features, explant histopathology, and clinical outcomes were compared.

RESULTS

Hepatocellular carcinoma was present in 80 of 317 patients, who underwent liver transplantation for steatohepatitis with equivalent distribution in non-alcoholic steatohepatitis and alcoholic liver disease patients (24% vs 26%; P = 0.8). On multivariate analysis, significant predictors of hepatocellular carcinoma included age, ethnicity (Hispanic), and diabetes, but not BMI, hypertension or smoking. A lower risk of hepatocellular carcinoma was associated with a clinical history of hyperlipidemia. Clinical parameters were similar between patients with alcoholic liver disease - hepatocellular carcinoma and non-alcoholic steatohepatitis-hepatocellular carcinoma, except sex and presence of metabolic syndrome. non-alcoholic steatohepatitis-hepatocellular carcinoma livers retained histopathological features of non-alcoholic steatohepatitis such as ballooning and Mallory bodies, while alcoholic liver disease-hepatocellular carcinoma livers did not. There were no significant differences in hepatocellular carcinoma recurrence rates or post-transplant overall survival.

CONCLUSIONS

We report the largest single-center study evaluating clinical, histopathological and outcome measures of patients undergoing liver transplantation for steatohepatitis. Older patients, diabetics, and Hispanics may warrant more frequent cancer screening due to increased risk of hepatocellular carcinoma.

Propensity-Matched Analysis of Patients with Mixed Hepatocellular-Cholangiocarcinoma and Hepatocellular Carcinoma Undergoing Liver Transplantation

Mixed hepatocellular-cholangiocarcinomas (HCC-CCAs) are rare tumors with both hepatocellular and biliary differentiation. While liver transplantation (LT) is the gold standard treatment for patients with unresectable hepatocellular carcinoma (HCC), it is contraindicated in known HCC-CCA because of concerns of poor prognosis. We sought to compare posttransplant oncologic outcomes for HCC-CCA and a matched cohort of HCC LT recipients. A retrospective, single-center analysis (1984-2015) identified 12 patients with mixed HCC-CCA who were matched 1:3 to patients with HCC on both pretransplant (radiologic diameter and alpha-fetoprotein) and explant (pathologic diameter, grade/differentiation, and vascular invasion) tumor characteristics. Compared with HCC patients matched on pretransplant characteristics (n = 36), HCC-CCA had higher explant tumor grade, more poorly differentiated tumors, but similar T stage and vascular invasion. HCC-CCA recipients trended toward inferior recurrence-free survival at 5 years (28% versus 61%; P = 0.12) and greater recurrence (HCC-CCA: 50%, median time to recurrence 297 days versus HCC: 22%, median time to recurrence 347 days; P = 0.07). However, when matched to a separate HCC cohort with similar explant pathology, HCC-CCA had similar 5-year recurrence-free survival (42% versus 44%; P = 0.45) and posttransplant recurrence (50% versus 27%; P = 0.13). All 6 HCC-CCA recurrences occurred with poorly differentiated tumors (median survival 21.3 months), without a single recurrence in 5 of the 12 HCC-CCA patients with well-moderately differentiated tumors (median survival 60.2 months). Mixed HCC-CCA tumors are more likely poorly differentiated tumors compared with HCC with similar pretransplant characteristics. However, compared with HCC with similar pathologic characteristics, they display similar recurrence-free survival and are not inherently more aggressive tumors. Low-grade, well-moderately differentiated HCC-CCAs have excellent survival with a low risk for post-LT recurrence, and they should not be excluded from LT. Improved pretransplant identification of pathologic characteristics in HCC-CCA may allow for successful utilization of LT in this subset of patients.

A novel multimarker assay for the phenotypic profiling of circulating tumor cells in hepatocellular carcinoma

Current clinicopathologic staging systems and serum biomarkers poorly discriminate tumor biology in hepatocellular carcinoma (HCC), with high recurrence rates following curative-intent surgical resection and liver transplantation (LT). Identification of accurate biomarkers for improved prognostication and treatment selection is a critical unmet need. We sought to develop a novel "liquid-biopsy" assay capable of detecting HCC circulating tumor cells (CTCs) and characterizing phenotypic subpopulations with prognostic significance. Using HCC cell lines, a tissue microarray, and human blood samples, an antibody cocktail targeting the cell-surface markers asialoglycoprotein receptor (ASGPR), glypican-3, and epithelial cell adhesion molecule was optimized for HCC CTC capture using the NanoVelcro CTC Assay. The ability of HCC CTCs and vimentin (VIM)-positive CTCs (a subpopulation expressing an epithelial-to-mesenchymal phenotype) to accurately discriminate tumor stage, recurrence, progression, and overall survival (OS) was evaluated in a prospective study of 80 patients. Multimarker capture detected greater numbers of CTCs than any individual antibody alone for both cell line and patient samples (P < 0.001). HCC CTCs were identified in 59/61 (97%) patients, and HCC (median, 6 CTCs) and non-HCC patients (median, 1 CTC; area under the receiver operating characteristic curve [AUROC] = 0.92; P < 0.001; sensitivity = 84.2%; specificity = 88.5%) were accurately discriminated. VIM-positive CTCs accurately discriminated early-stage, LT eligible patients (median, 0 CTCs) from locally advanced/metastatic, LT ineligible patients (median, 6 CTCs; AUROC = 0.89; P = 0.001; sensitivity = 87.1%; specificity = 90.0%), and predicted OS for all patients (hazard ratio [HR], 2.21; P = 0.001), and faster recurrence after curative-intent surgical or locoregional therapy in potentially curable early-stage HCC (HR, 3.14; P = 0.002). In conclusion, we developed a novel multimarker CTC enrichment assay that detects HCC CTCs with high efficiency and accuracy. A phenotypic subpopulation of VIM-positive CTCs appears to signify the presence of aggressive underlying disease and occult metastases and may have important implications for treatment selection. Liver Transplantation 24 946-960 2018 AASLD.

Obliterative portal venopathy: A histopathologic finding associated with chronic antibody-mediated rejection in pediatric liver allografts

The significance of post-transplant HLA DSA and chronic AMR in LT is an emerging field of study. Although OPV has previously been described as a histopathologic finding in DSA-positive adult LT recipients, it was not included in the recent Banff criteria for chronic AMR. Our aim was to describe the association between OPV and chronic AMR in pediatric LT recipients. A retrospective review of 67 liver biopsies performed between November 2014 and April 2016 in 45 pediatric LT recipients identified four patients with OPV. Clinical status, liver biochemistry, the presence of DSA, and available non-HLA antibody testing, as well as histopathologic features of chronic AMR, were assessed. All four patients with OPV had class II DSA and histopathologic features of chronic AMR based on the Banff criteria. Two patients were noted to have non-HLA antibodies. Three patients are undergoing treatment with IVIG but have persistent DSA. Two patients have graft failure and are awaiting retransplantation. In conclusion, OPV is a histopathologic finding associated with chronic AMR in pediatric LT recipients. Further studies are needed to elucidate whether OPV is reversible and/or amenable to medical therapy.

Treponema pallidum Immunohistochemistry is positive in human intestinal Spirochetosis

BACKGROUND

Human intestinal spirochetosis (IS) has been recognized for decades, but whether it represents commensalism or a pathogenic process remains controversial. IS is diagnosed on routine stains with confirmation by silver stains but these stains are labor intensive and slow to read. We evaluated the Treponema pallidum immunostain as a diagnostic adjunct for IS.

METHODS

We retrieved biopsies from 33 patients with IS for this study. Each case was tested by Warthin-Starry (WS) and T. pallidum immunohistochemistry (IHC). Species specific genotyping was performed in 3 cases.

RESULTS

Patients with IS ranged from 22 to 82 years without gender predilection. IS involved normal (n = 15), and inflamed (n = 5) mucosa and colonic polyps (n = 13). Warthin-Starry and T. pallidum IHC were positive in all cases including both species of Brachyspira. Six (18%) symptomatic patients were treated for IS, and experienced resolution. In patients diagnosed with incidental IS on cancer screening (n = 5), follow up biopsies, without therapy, were negative for IS. T. pallidum IHC required 75 min less hands-on time than WS for performance and was faster to interpret.

CONCLUSIONS

T. pallidum IHC can be used to confirm the diagnosis of IS and is easier to perform and faster to interpret than WS.

Determination of hepatocellular carcinoma grade by needle biopsy is unreliable for liver transplant candidate selection

The objective of this article is to evaluate the utility of preoperative needle biopsy (PNB) grading of hepatocellular carcinoma (HCC) as a biomarker for liver transplantation (LT) candidate selection. Given the prognostic significance of HCC tumor grade, PNB grading has been proposed as a biomarker for LT candidate selection. Clinicopathologic characteristics of HCC LT recipients (1989-2014) with a PNB were analyzed, and the concordance of PNB grade to explant grade and vascular invasion was assessed to determine whether incorporation of PNB grade to accepted transplant criteria improved candidate selection. Of 965 patients undergoing LT for HCC, 234 (24%) underwent PNB at a median of 280 days prior to transplant. Grade by PNB had poor concordance to final explant pathology (κ = 0.22; P = 0.003), and low sensitivity (29%) and positive predictive value (35%) in identifying poorly differentiated tumors. Vascular invasion was predicted by explant pathologic grade (r_s= 0.24; P < 0.001) but not PNB grade (r_s = -0.05; P = 0.50). Increasing explant pathology grade (P = 0.02), but not PNB grade (P = 0.65), discriminated post-LT HCC recurrence risk. The incorporation of PNB grade to the established radiologic Milan criteria (MC) did not result in improved prognostication of post-LT recurrence (net reclassification index [NRI] = 0%), whereas grade by explant pathology resulted in significantly improved reclassification of risk (NRI = 19%). Preoperative determination of HCC grade by PNB has low concordance with explant pathologic grade and low sensitivity and positive predictive value in identifying poorly differentiated tumors. PNB grade did not accurately discriminate post-LT HCC recurrence and had no utility in improving prognostication compared with the MC alone. Incorporation of PNB to guide transplant candidate selection appears unjustified. Liver Transplantation 23 1123-1132 2017 AASLD.

Acute antibody-mediated rejection in ABO-compatible pediatric liver transplant recipients: case series and review of the literature

Acute AMR is well reported following ABO-incompatible LTx. However, it remains uncommon in ABO-compatible LTx. It typically presents with graft dysfunction ≤2 weeks post-LTx and is often associated with graft loss. We report the clinical presentation, treatment regimen, and outcome of six pediatric LTx recipients diagnosed with early acute AMR based on (i) clinical signs of graft dysfunction, (ii) histopathology indicative of acute injury ± C4d staining, and (iii) presence of HLA DSA. All patients developed elevated ALT and GGT ≤ 45 days post-LTx. All showed HLA class I (n=4) and/or II (n=6) DSA (peak MFI 6153-11 910). Four had de novo DSA, and two had preformed DSA. Five were initially diagnosed with ACR refractory to steroid therapy. Four exhibited resolution of graft dysfunction with AMR therapy. Two had refractory AMR-one was re-transplanted; the other was treated with eculizumab and showed improvement in graft function but later died due to a tracheostomy complication. Our case series suggests that AMR following ABO-compatible LTx may be under-diagnosed. The presentation can be variable, and treatment should be individualized. Eculizumab may be an option for refractory AMR. Ultimately, future multicenter studies are needed to better define diagnostic criteria, characterize optimal treatment, and assess long-term outcomes following liver AMR.

The Differentiation of Intestinal-Failure-Associated Liver Disease from Nonalcoholic Fatty Liver and Nonalcoholic Steatohepatitis

Intestinal failure-associated liver disease (IFALD), formerly known as parenteral nutrition-associated liver disease has often been listed in textbooks as an example of nonalcoholic fatty liver disease (NAFLD). However, the etiology, pathophysiology, epidemiology, histology, and progression differ substantially between the conditions defined as NAFLD and the disease, IFALD. Therefore, IFALD should not be defined or considered as a type or a cause of nonalcoholic fatty liver or nonalcoholic steatohepatitis, but rather as a distinct disease.

Challenges to "Classic" Esophageal Candidiasis: Looks Are Usually Deceiving

Objectives

We undertook the first case control study of histologically confirmed esophageal candidiasis (EC).

Methods

A computer search from July 2012 through February 2015 identified 1,011 esophageal specimens, including 40 cases of EC and 20 controls.

Results

The EC incidence was 5.2%; it was associated with immunosuppression and endoscopic white plaques and breaks. Smoking was a predisposing factor, and alcohol was protective. EC had no unique symptoms, and 54% of endoscopic reports did not suspect EC. Important histologic clues included superficial and detached fragments of desquamated and hyper-pink parakeratosis, acute inflammation, intraepithelial lymphocytosis, dead keratinocytes, and bacterial overgrowth. Thirty percent had no neutrophilic infiltrate. Pseudohyphae were seen on H&E in 92.5% (n = 37/40). "Upfront" periodic acid-Schiff with diastase (PAS/D) on all esophageal specimens would have generated $68,333.49 in patient charges. Our targeted PAS/D strategy resulted in $13,044.87 in patient charges (cost saving = 80.9%, $55,288.62).

Conclusions

We describe the typical morphology of EC and recommend limiting PAS/D to cases where the organisms are not readily identifiable on H&E and with at least one of the following: (1) ulcer, (2) suspicious morphology, and/or (3) clinical impression of EC.

Early cytokine signatures of ischemia/reperfusion injury in human orthotopic liver transplantation

BACKGROUND. Orthotopic liver transplant (OLT) is the primary therapy for end-stage liver disease and acute liver failure. However, ischemia/reperfusion injury (IRI) can severely compromise allograft survival. To understand the evolution of immune responses underlying OLT-IRI, we evaluated longitudinal cytokine expression profiles from adult OLT recipients before transplant through 1 month after transplant. METHODS. We measured the expression of 38 cytokines, chemokines, and growth factors in preoperative and postoperative recipient circulating systemic blood (before transplant and 1 day, 1 week, and 1 month after transplant) and intraoperative portal blood (before and after reperfusion) of 53 OLT patients and analyzed this expression in relation to biopsy-proven IRI (n = 26 IRI+; 27 IRI-), clinical liver function tests early (days 1-7) after transplant, and expression of genes encoding cytokine receptors in biopsies of donor allograft taken before and after reperfusion. RESULTS. Bilirubin and arginine transaminase levels early after transplant correlated with IRI. Fourteen cytokines were significantly increased in the systemic and/or portal blood of IRI+ recipients that shifted from innate to adaptive-immune responses over time. Additionally, expression of cognate receptors for 10 of these cytokines was detected in donor organ biopsies by RNAseq. CONCLUSION. These results provide a mechanistic roadmap of the early immunological events both before and after IRI and suggest several candidates for patient stratification, monitoring, and treatment. FUNDING. Ruth L. Kirschstein National Research Service Award T32CA009120, Keck Foundation award 986722, and a Quantitative & Computational Biosciences Collaboratory Postdoctoral Fellowship.

Allograft biopsy findings in patients with small bowel transplantation

In this study, we sought to determine the incidence of post-transplant complications including acute cellular rejection (ACR), infection, and post-transplant lymphoproliferative disease (PTLD) in mucosal allograft biopsies in patients with small bowel transplant at our institution. We retrospectively reviewed pathology reports from 5675 small bowel allograft biopsies from 99 patients and analyzed the following: indications for biopsy, frequency and grade of ACR, the presence of infectious agents, results of workup for potential PTLD, results of C4d immunohistochemistry (IHC), features of chronic mucosal injury, and findings in concurrent native bowel biopsies. Findings from 42 allograft resection specimens were also correlated with prior biopsy findings. Indeterminate, mild, moderate, and severe ACR were seen in 276 (4.9%), 409 (7.2%), 100 (1.8%), and 207 (3.6%) of biopsies, respectively. Although ACR may show histologic overlap with mycophenolate mofetil toxicity, we found the analysis of concurrent native bowel biopsies to be helpful in this distinction. Adenovirus was the most common infectious agent seen (11%), and we routinely performed adenovirus IHC on biopsies. Eighteen patients (18%) developed PTLD, 83% of which were EBV associated, but only 28% of PTLD cases were diagnosed on mucosal allograft biopsies. C4d IHC did not correlate with the presence of donor-specific antibodies in limited cases.

Intraductal Oncocytic Papillary Neoplasms of the Pancreas

Intraductal oncocytic papillary neoplasms (IOPNs) are cystic neoplasms with intraductal growth and complex papillae composed of oncocytic cells. IOPNs have been reported both in the pancreas and biliary tree, and are most likely closely related in these 2 locations. In the pancreas, these rare tumors are now considered 1 of the 4 histologic subtypes of intraductal papillary mucinous neoplasm (IPMN). Significant differences in histology, immunophenotype, and molecular genetics have been reported between IOPNs and other IPMN subtypes. However, there are limited data regarding the clinical behavior and prognosis of IOPNs in comparison to other subtypes of IPMN. We review features of pancreatic IOPNs and discuss the differential diagnosis of other intraductal lesions in the pancreas.

TLR4 Signaling via NANOG Cooperates With STAT3 to Activate Twist1 and Promote Formation of Tumor-Initiating Stem-Like Cells in Livers of Mice

BACKGROUND & AIMS

Obesity and alcohol consumption contribute to steatohepatitis, which increases the risk for hepatitis C virus (HCV)-associated hepatocellular carcinomas (HCCs). Mouse hepatocytes that express HCV-NS5A in liver up-regulate the expression of Toll-like receptor 4 (TLR4), and develop liver tumors containing tumor-initiating stem-like cells (TICs) that express NANOG. We investigated whether the TLR4 signals to NANOG to promote the development of TICs and tumorigenesis in mice placed on a Western diet high in cholesterol and saturated fat (HCFD).

METHODS

We expressed HCV-NS5A from a transgene (NS5A Tg) in Tlr4-/- (C57Bl6/10ScN), and wild-type control mice. Mice were fed a HCFD for 12 months. TICs were identified and isolated based on being CD133+, CD49f+, and CD45-. We obtained 142 paraffin-embedded sections of different stage HCCs and adjacent nontumor areas from the same patients, and performed gene expression, immunofluorescence, and immunohistochemical analyses.

RESULTS

A higher proportion of NS5A Tg mice developed liver tumors (39%) than mice that did not express HCV NS5A after the HCFD (6%); only 9% of Tlr4-/- NS5A Tg mice fed HCFD developed liver tumors. Livers from NS5A Tg mice fed the HCFD had increased levels of TLR4, NANOG, phosphorylated signal transducer and activator of transcription (pSTAT3), and TWIST1 proteins, and increases in Tlr4, Nanog, Stat3, and Twist1 messenger RNAs. In TICs from NS5A Tg mice, NANOG and pSTAT3 directly interact to activate expression of Twist1. Levels of TLR4, NANOG, pSTAT3, and TWIST were increased in HCC compared with nontumor tissues from patients.

CONCLUSIONS

HCFD and HCV-NS5A together stimulated TLR4-NANOG and the leptin receptor (OB-R)-pSTAT3 signaling pathways, resulting in liver tumorigenesis through an exaggerated mesenchymal phenotype with prominent Twist1-expressing TICs.

Qualitative and Quantitative Gadoxetic Acid-enhanced MR Imaging Helps Subtype Hepatocellular Adenomas

PURPOSE

To determine which clinical variables and gadoxetic acid disodium (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) imaging features are associated with histologically proved hepatocellular adenoma (HCA) genotypic subtypes.

MATERIALS AND METHODS

In this institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study, clinical information and MR images of 49 histologically proved HCAs from January 2002 to December 2013 (21 patients; mean age, 39 years; age range, 15-59 years) were retrospectively reviewed by two radiologists. Qualitative and quantitative imaging features, including the signal intensity ratio relative to liver in each phase, were studied. HCA tissues were stained with subtype-specific markers and subclassified by a pathologist. Clinical and imaging data were correlated with pathologic findings and compared by using Fisher exact or t test, with a Bonferroni correction for multiple comparisons.

RESULTS

Forty-nine HCAs were subclassified into 14 inflammatory, 20 hepatocyte nuclear factor (HNF)-1α-mutated, one β-catenin-activated, and 14 unclassified lesions. Intralesional steatosis was exclusively seen in HNF-1α-mutated lesions. Marked hyperintensity on T2-weighted images was seen in 12 of 14 (86%) inflammatory lesions compared with four of 21 (19%) HNF-1α-mutated, seven of 14 (50%) unclassified, and zero of one (0%) β-catenin-activated lesion. Two large lesions (one β-catenin-activated and one unclassified) transformed into hepatocellular carcinomas and were the only lesions to enhance with marked heterogeneity. In the hepatobiliary phase, all HCA subtypes were hypoenhancing compared with surrounding liver parenchyma, and they reached their nadir signal intensity by 10 minutes after the administration of contrast material before plateauing. HNF-1α-mutated lesions had the lowest lesion signal intensity ratio of 0.47 ± 0.09, compared with 0.73 ± 0.18 for inflammatory lesions (P = .0004), 0.82 for the β-catenin-activated lesion, and 0.73 ± 0.06 for the unclassified lesion (P = .00002).

CONCLUSION

In this study, all HCA subtypes were hypoenhancing at Gd-EOB-DTPA-enhanced MR imaging in the hepatobiliary phase and reached their nadir signal intensity at 10 minutes. HNF-1α-mutated lesions could be distinguished from other subtypes by having the lowest lesion signal intensity ratio.

Barrett's oesophagus diagnostic criteria: endoscopy and histology

This review summarizes the endoscopic and histologic features of Barrett's oesophagus(BO) as well as some of the recent advancements and controversies. BO represents metaplastic conversion of normal squamous epithelium of tubular oesophagus to columnar epithelium. The diagnosis of BO requires a combination of endoscopic and histopathologic findings. There is worldwide controversy regarding the exact definition of BO, particularly with regard to the requirement to histologically identify goblet cells in biopsies. The presence and detectability of goblet cells might vary depending on a variety of factors and is subject to sampling error. Therefore, a systematic biopsy sampling with sufficient number of biopsies is currently recommended to limit the likelihood of a false negative result for detection of goblet cells. There are both endoscopic and pathologic challenges in evaluating gastro-oesophageal junction biopsies in patients with irregular Z lines to determine the exact location of the sample (i.e., oesophagus versus stomach). Recently, several novel endoscopic techniques have been developed to improve BO detection. However, none have been validated yet in clinical practice. The surveillance of patients with BO relies on histologic evaluation of dysplasia. However, there are significant pathologic limitations and diagnostic variability in evaluating the presence and grading of BO dysplasia, particularly with regard to the more recently recognized non-intestinal types of dysplasia. All BO dysplasia samples should be reviewed by an expert gastrointestinal pathologist to confirm the diagnosis. Finally, it is important to emphasize that close interaction between gastroenterologists and pathologists is essential to ensure proper evaluation of endoscopic biopsies in order to optimize the surveillance and clinical management of patients with BO.

Chromophobe hepatocellular carcinoma with abrupt anaplasia: a proposal for a new subtype of hepatocellular carcinoma with unique morphological and molecular features

Hepatocellular carcinomas exhibit heterogeneous morphologies by routine light microscopy. Although some morphologies represent insignificant variations in growth patterns, others may represent unrecognized subtypes of hepatocellular carcinoma. Identification of these subtypes could lead to separation of hepatocellular carcinomas into discrete groups with unique underlying genetic changes, prognosis, or therapeutic responses. In order to identify potential subtypes, two pathologists independently screened a cohort of 219 unselected hepatocellular carcinoma resection specimens and divided cases into potential subtypes. One of these promising candidate subtypes was further evaluated using histological and molecular techniques. This subtype was characterized by a unique and consistent set of histological features: smooth chromophobic cytoplasm, abrupt focal nuclear anaplasia (small clusters of tumor cells with marked nuclear anaplasia in a background of tumor cells with bland nuclear cytology), and scattered microscopic pseudocysts--we designate this variant as 'chromophobe hepatocellular carcinoma with abrupt anaplasia'. Thirteen cases were identified (6% of all hepatocellular carcinomas), including 6 men and 7 women with an average age of 61 years. Six cases occurred in cirrhotic livers. Serum AFP was elevated in 6 out of 10 cases. There were a variety of underlying liver diseases, but cases were enrichment for chronic hepatitis B, P=0.006. Interestingly, at the molecular level, this variant was strongly associated with the alternative lengthening of telomere (ALT) phenotype by telomere FISH. ALT is a telomerase-independent mechanism of telomere maintenance and is found in approximately 8% of unselected hepatocellular carcinomas. In contrast, 11/12 (92%) of the cases of chromophobe hepatocellular carcinoma with abrupt anaplasia were ALT-positive. In summary, we propose that chromophobe hepatocellular carcinoma with abrupt anaplasia represents a new subtype of hepatocellular carcinoma with unique morphological and molecular features.

Liver Transplant Pathology: Review of Challenging Diagnostic Situations

Histopathologic assessment of allograft liver biopsies has an important role in managing patients who have undergone liver transplantation. In this review, several topics are discussed that create diagnostic problems in transplant pathology, with emphasis on pathologic features and differential diagnosis. The topics discussed are acute cellular rejection, late acute rejection (centrizonal/parenchymal rejection), chronic rejection, plasma cell hepatitis, idiopathic posttransplant chronic hepatitis, fibrosing cholestatic hepatitis, selected viral infections (cytomegalovirus, Epstein-Barr virus, and hepatitis E), and acute antibody-mediated rejection.

Advanced precancerous lesions (APL) in the colonic mucosa

Colorectal cancer is a leading cause of cancer death worldwide. Most colorectal cancers are preventable. Surveillance colonoscopy is used to detect and remove precancerous lesions. Although the majority of precancerous lesions develop sporadically, some have an inherited component. In this review, we summarize the clinical, pathologic, and molecular features of advanced precancerous lesions of the colon. The most common and clinically important intestinal polyposis syndromes, and their genetics, are also discussed. Finally, current recommendations regarding the treatment and surveillance of precancerous lesions, both in the sporadic and in inherited setting, are reviewed.

Assessment of hepatic steatosis by transplant surgeon and expert pathologist: a prospective, double-blind evaluation of 201 donor livers

An accurate clinical assessment of hepatic steatosis before transplantation is critical for successful outcomes after liver transplantation, especially if a pathologist is not available at the time of procurement. This prospective study investigated the surgeon's accuracy in predicting hepatic steatosis and organ quality in 201 adult donor livers. A steatosis assessment by a blinded expert pathologist served as the reference gold standard. The surgeon's steatosis estimate correlated more strongly with large-droplet macrovesicular steatosis [ld-MaS; nonparametric Spearman correlation coefficient (rS ) = 0.504] versus small-droplet macrovesicular steatosis (sd-MaS; rS  = 0.398). True microvesicular steatosis was present in only 2 donors (1%). Liver texture criteria (yellowness, absence of scratch marks, and round edges) were mainly associated with ld-MaS (variance = 0.619) and were less associated with sd-MaS (variance = 0.264). The prediction of ≥30% ld-MaS versus <30% ld-MaS was excellent when liver texture criteria were used (accuracy = 86.2%), but it was less accurate when the surgeon's direct estimation of the steatosis percentage was used (accuracy = 75.5%). The surgeon's quality grading correlated with the degree of ld-MaS and the surgeon's steatosis estimate as well as the incidence of poor initial function and primary nonfunction. In conclusion, the precise estimation of steatosis remains challenging even in experienced hands. Liver texture characteristics are more helpful in identifying macrosteatotic organs than the surgeon's actual perception of steatosis. These findings are especially important when histological assessment is not available at the donor's hospital.

A histopathologic scoring system as a tool for standardized reporting of chronic (ileo)colitis and independent risk assessment for inflammatory bowel disease

Pathologists regularly evaluate for the presence of chronic (ileo)colitis in lower gastrointestinal mucosal biopsies, for which a major differential diagnosis is inflammatory bowel disease. Although the histologic features of chronic (ileo)colitis are clearly defined, there is no standard, experimentally derived and validated terminology to document these findings in pathology reports and to convey the likelihood of inflammatory bowel disease in a compact, consistent style. This study had 2 retrospective and 1 prospective phases. In phase 1, we developed a histopathologic scoring system for chronic (ileo)colitis and measured the agreement in scoring between pathologists. In phase 2, we emulated the surgical pathology practice by scoring mucosal biopsies of 164 patients who had undergone lower gastrointestinal endoscopies for clinical suspicion of (ileo)colitis. The cases were matched to 6 different groups based on clinical diagnoses. In phase 3, we prospectively assessed accuracy and ease of application of the scoring system in our practice. The scoring system showed low interobserver variability (correlation coefficient, 0.94-0.96) and distinguished chronic (ileo)colitis from negative cases. In addition, it enabled us to provide probabilistic diagnostic statements based on total scores and their positive predictive values, conveying the likelihood of inflammatory bowel disease as low (<20%), intermediate (∼50%), and high (∼90%). In conclusion, this histopathologic scoring system might be a useful approach to report the findings of lower gastrointestinal mucosal biopsies and to provide measured opinion regarding chronic (ileo)colitis independent of available clinical information. In addition, a defined set of diagnostic statements with regard to likelihood of inflammatory bowel disease would reduce interpretive variability.

A correlation study on diagnostic endoscopic ultrasound-guided fine-needle aspiration of lymph nodes with histological and clinical diagnoses, the UCLA Medical Center experience

Endoscopic ultrasound guided (EUS) FNA procedure has two aspects, the endoscopic sampling and the FNA interpretation. The two aspects of the procedure are performed in two different disciplines; gastroenterology (EUS) and pathology (FNA). The aim of this study was to evaluate the concordance, sensitivity, specificity, positive predictive (PPV), and negative predictive values (NPV).Sixty-one EUS-FNA procedures of the lymph nodes were analyzed by correlating the FNA results with histological or clinical diagnoses. The lymph nodes were divided in five groups; mediastinal, gastrohepatic, peripancreatic, portal, and perirectal.The study showed a concordance of 92% in mediastinal, 80% in gastrohepatic, 81% in peripancreatic, 95% in portal, and 100% in perirectal lymph nodes with an overall sensitivity of 84%, specificity of 92%, PPV of 88%, and NPV of 89%. In conclusion, EUS-FNA offers an invaluable approach for diagnostic examination of the internal lymph nodes where percutaneous FNA is either difficult or impossible. impossible.