Gregory Miller

ELF score ≥9.8 indicates advanced hepatic fibrosis and is influenced by age, steatosis and histological activity

There is increasing need to identify individuals with advanced liver fibrosis, who are at risk of complications such as hepatocellular carcinoma. The commercially available enhanced liver fibrosis (ELF) test provides a non‐invasive assessment of fibrosis severity. This study was designed to determine the diagnostic accuracy of the manufacturers cut‐off value (≥9.8) in identifying advanced fibrosis.

Aspartate aminotransferase to platelet ratio and fibrosis-4 as biomarkers in biopsy-validated pediatric cystic fibrosis liver disease

Up to 10% of cystic fibrosis (CF) children develop cirrhosis by the first decade. We evaluated the utility of two simple biomarkers, aspartate aminotransferase to platelet ratio index (APRI) and FIB‐4, in predicting degree of fibrosis in pediatric CF liver disease (CFLD) validated by liver biopsy. In this retrospective, cross‐sectional study, 67 children with CFLD had dual‐pass liver biopsies and 104 age‐ and sex‐matched CF children without liver disease (CFnoLD) had serum to calculate APRI and FIB‐4 collected at enrollment. CFLD was defined as having two of the following: (1) hepatomegaly ± splenomegaly; (2) >6 months elevation of ALT (>1.5× upper limit of normal ULN); or (3) abnormal liver ultrasound findings. Biopsies were staged according to Metavir classification by two blinded pathologists. Receiver operating characteristic (ROC) analysis and continuation ratio logistic regression were performed to assess the predictability of these biomarkers to distinguish CFLD from CFnoLD and determine fibrosis stage‐specific cut‐off values. The AUC for APRI was better than FIB‐4 (0.75 vs. 0.60; P = 0.005) for predicting CFLD and severe CFLD (F3‐F4) (0.81). An APRI score >0.264 demonstrated a sensitivity (95% confidence interval [CI]) of 73.1% (60.9, 83.2) and specificity of 70.2% (60.4, 78.8) in predicting CFLD. A 50% increase in APRI was associated with a 2.4‐fold (95% CI: 1.7, 3.3) increased odds of having CFLD. APRI demonstrated full agreement with histology staging 37% of the time, but was within one stage 73% of the time. Only FIB‐4 predicted portal hypertension at diagnosis (area under the receiver operator characteristic curve [AUC] = 0.91; P < 0.001). Conclusion: This is the first liver biopsy‐validated study of APRI and FIB‐4 in pediatric CFLD. APRI appears superior to FIB‐4 in differentiating CFLD versus CFnoLD. APRI also exhibited a high AUC in predicting severe liver fibrosis with specific cutoffs for lower stages. (Hepatology 2015;62:1576–1583)

The Enhanced liver fibrosis score is associated with clinical outcomes and disease progression in patients with chronic liver disease

Current tools for risk stratification of chronic liver disease subjects are limited. We aimed to determine whether the serum‐based ELF (Enhanced Liver Fibrosis) test predicted liver‐related clinical outcomes, or progression to advanced liver disease, and to compare the performance of ELF to liver biopsy and non‐invasive algorithms.

Adverse histological features in malignant colorectal polyps: a contemporary series of 239 cases.

Aims Screening colonoscopy has led to more colorectal carcinomas presenting at an early stage potentially curable by endoscopic resection. In this study, we examined the clinical and histological features of a contemporary series of malignant colorectal polyps (MCPs) with subsequent surgical resection. Methods We conducted a retrospective study on a consecutive series of MCPs from 239 patients, predominantly males (57.7%) with a median age of 66 years, and assessed histological parameters associated with residual disease on the surgical specimens. Results Median MCP size was 18.6 mm, with 23.1% polyps measuring ≤10 mm. From the 140 surgical resection specimens, residual disease was identified in 20 cases, including 12 cases with metastatic lymph nodes and/or 9 cases with residual carcinoma in the large bowel wall. Histological parameters associated with nodal metastases were greater width and greater depth of the invasive component (p=0.001 and 0.006, respectively), poor differentiation (p=0.003) and a cribriform pattern (p=0.01). The risk of nodal metastases was 23.3% if two or three of these features were identified, while it was 0% and 4.5% if none or one was present, respectively. A positive margin was not associated with nodal metastasis and might be adequately treated by local endoscopic resection. Conclusions Surgical resection should be recommended if ≥2 of these adverse histological features are present and may be warranted if one feature is present. A positive margin may require additional local resection but not necessarily surgery if no other adverse factors are present.

Acute GVHD results in a severe DC defect that prevents T-cell priming and leads to fulminant cytomegalovirus disease in mice

Viral infection is a common, life-threatening complication after allogeneic bone marrow transplantation (BMT), particularly in the presence of graft-versus-host disease (GVHD). Using cytomegalovirus (CMV) as the prototypic pathogen, we have delineated the mechanisms responsible for the inability to mount protective antiviral responses in this setting. Although CMV infection was self-limiting after syngeneic BMT, in the presence of GVHD after allogeneic BMT, CMV induced a striking cytopathy resulting in universal mortality in conjunction with a fulminant necrotizing hepatitis. Critically, GVHD induced a profound dendritic cell (DC) defect that led to a failure in the generation of CMV-specific CD8(+) T-cell responses. This was accompanied by a defect in antiviral CD8(+) T cells. In combination, these defects dramatically limited antiviral T-cell responses. The transfer of virus-specific cells circumvented the DC defects and provided protective immunity, despite concurrent GVHD. These data demonstrate the importance of avoiding GVHD when reconstructing antiviral immunity after BMT, and highlight the mechanisms by which the adoptive transfer of virus-specific T cells overcome the endogenous defects in priming invoked by GVHD.

Spatiotemporal Characterization of the Cellular and Molecular Contributors to Liver Fibrosis in a Murine Hepatotoxic-Injury Model.

The interplay between the inflammatory infiltrate and tissue resident cell populations invokes fibrogenesis. However, the temporal and mechanistic contributions of these cells to fibrosis are obscure. To address this issue, liver inflammation, ductular reaction (DR), and fibrosis were induced in C57BL/6 mice by thioacetamide administration for up to 12 weeks. Thioacetamide treatment induced two phases of liver fibrosis. A rapid pericentral inflammatory infiltrate enriched in F4/80(+) monocytes co-localized with SMA(+) myofibroblasts resulted in early collagen deposition, marking the start of an initial fibrotic phase (1 to 6 weeks). An expansion of bone marrow-derived macrophages preceded a second phase, characterized by accelerated progression of fibrosis (>6 weeks) after DR migration from the portal tracts to the centrilobular site of injury, in association with an increase in DR/macrophage interactions. Although chemokine (C-C motif) ligand 2 (CCL2) mRNA was induced rapidly in response to thioacetamide, CCL2 deficiency only partially abrogated fibrosis. In contrast, colony-stimulating factor 1 receptor blockade diminished C-C chemokine receptor type 2 [CCR2(neg) (Ly6C(lo))] monocytes, attenuated the DR, and significantly reduced fibrosis, illustrating the critical role of colony-stimulating factor 1-dependent monocyte/macrophage differentiation and linking the two phases of injury. In response to liver injury, colony-stimulating factor 1 drives early monocyte-mediated myofibroblast activation and collagen deposition, subsequent macrophage differentiation, and their association with the advancing DR, the formation of fibrotic septa, and the progression of liver fibrosis to cirrhosis.

Deletion of Wntless in myeloid cells exacerbates liver fibrosis and the ductular reaction in chronic liver injury

BackgroundMacrophages play critical roles in liver regeneration, fibrosis development and resolution. They are among the first responders to liver injury and are implicated in orchestrating the fibrogenic response via multiple mechanisms. Macrophages are also intimately associated with the activated hepatic progenitor cell (HPC) niche or ductular reaction that develops in parallel with fibrosis. Among the many macrophage-derived mediators implicated in liver disease progression, a key role for macrophage-derived Wnt proteins in driving pro-regenerative HPC activation towards a hepatocellular fate has been suggested. Wnt proteins, in general, however, have been associated with both pro- and anti-fibrogenic activities in the liver and other organs. We investigated the role of macrophage-derived Wnt proteins in fibrogenesis and HPC activation in murine models of chronic liver disease by conditionally deleting Wntless expression, which encodes a chaperone essential for Wnt protein secretion, in LysM-Cre-expressing myeloid cells (LysM-Wls mice).ResultsFibrosis and HPC activation were exacerbated in LysM-Wls mice compared to littermate controls, in the absence of an apparent increase in myofibroblast activation or interstitial collagen mRNA expression, in both the TAA and CDE models of chronic liver disease. Increased Epcam mRNA levels paralleled the increased HPC activation and more mature ductular reactions, in LysM-Wls mice. Increased Epcam expression in LysM-Wls HPC was also observed, consistent with a more cholangiocytic phenotype. No differences in the mRNA expression levels of key pro-inflammatory and pro-fibrotic cytokines or the macrophage-derived HPC mitogen, Tweak, were observed. LysM-Wls mice exhibited increased expression of Timp1, encoding the key Mmp inhibitor Timp1 that blocks interstitial collagen degradation, and, in the TAA model, reduced expression of the anti-fibrotic matrix metalloproteinases, Mmp12 and Mmp13, suggesting a role for macrophage-derived Wnt proteins in restraining fibrogenesis during ongoing liver injury.ConclusionIn summary, these data suggest that macrophage-derived Wnt proteins possess anti-fibrogenic potential in chronic liver disease, which may be able to be manipulated for therapeutic benefit.

The pathological findings seen in laparoscopic sleeve gastrectomies for weight loss

Sleeve gastrectomy specimens are increasingly common surgical specimens received for examination following bariatric surgery for weight loss. The spectrum of pathological changes seen in these cases is not well documented. Retrospective examination was undertaken of 1463 consecutive sleeve gastrectomy specimens received at Envoi Specialist Pathologists. Most cases showed no pathological changes (80.2%). The most common changes seen were non-specific, non-Helicobacter associated chronic gastritis (7.2%), Helicobacter associated gastritis (6.8%) and benign fundic gland polyps (4.0%). Other, rarer changes were lymphocytic gastritis, autoimmune atrophic gastritis, chronic gastritis with intestinal metaplasia, hyperplastic polyps, pancreatic heterotopia, gastrointestinal stromal tumours (GISTs) and a leiomyoma. A wide range of pathological changes are seen in resection specimens following sleeve gastrectomies for weight loss. Many cases will require further treatment or ongoing investigation and surveillance.

Ferroportin expression in adipocytes does not contribute to iron homeostasis or metabolic responses to a high calorie diet

Background & Aims Iron has an increasingly recognized role in the regulation of adipose tissue function, including the expression of adipokines involved in the pathogenesis of nonalcoholic fatty liver disease. The cellular iron exporter, ferroportin, has been proposed as being a key determinant of adipocyte iron homeostasis. Methods We studied an adipocyte-specific ferroportin (Fpn1) knockout mouse model, using an Adipoq-Cre recombinase driven Fpn1 deletion and fed mice according to the fast food diet model of nonalcoholic steatohepatitis. Results We showed successful selective deletion of Fpn1 in adipocytes, but found that this did not lead to increased adipocyte iron stores as measured by atomic absorption spectroscopy or histologically quantified iron granules after staining with 3,3’-diaminobenzidine–enhanced Perls’ stain. Mice with adipocyte-specific Fpn1 deletion did not show dysregulation of adiponectin, leptin, resistin, or retinol-binding protein-4 expression. Similarly, adipocyte-specific Fpn1 deletion did not affect insulin sensitivity during hyperinsulinemic–euglycemic clamp studies or lead to histologic evidence of increased liver injury. We have shown, however, that the fast food diet model of nonalcoholic steatohepatitis generates an increase in adipose tissue macrophage infiltration with crown-like structures, as seen in human beings, further validating the utility of this model. Conclusions Ferroportin may not be a key determinant of adipocyte iron homeostasis in this knockout model. Further studies are needed to determine the mechanisms of iron metabolism in adipocytes and adipose tissue.

Yield of Universal Testing for DNA Mismatch Repair Protein Deficiency in Colorectal Carcinoma From an Australian Community-based Practice

Lynch syndrome is the most common cause of inherited colorectal carcinoma (CRC). Testing all newly diagnosed CRC for MMR protein deficiency, known as universal testing, has recently emerged as the preferred approach to identify potential Lynch syndrome individuals. All newly diagnosed CRCs were screened for MMR protein expression by immunohistochemistry. A 2-step approach was used: PMS2 and MSH6 testing followed by the testing of the respective MMR protein partner if one of the proteins is lost. We retrospectively searched our pathology database for MMR protein expression results across a 5-year period (2012-2016) when universal testing was performed. Clinical and pathological data were extracted from the pathology report. A total of 2077 consecutive CRCs were tested for MMR protein expression. Mean age at diagnosis was 68.4 years. MMR protein deficiency was identified in 399 cases (19.2%). The vast majority of CRC with MLH1/PMS2 loss were diagnosed in patients older than 70 years (84%), most of them are likely to be secondary to sporadic MLH1 methylation. MMR protein deficiency patterns suggestive of a defect in MSH2, MSH6 or PMS2 comprised 42 cases, of which 37 were found in individuals aged 50 years or older. CRCs with MSH2/MSH6 loss were most commonly found in patients older than 70 years (57%). In summary, universal testing for MMR protein deficiency in CRC identifies abnormal patterns of expression suggestive of Lynch syndrome in all age groups. Further studies are needed to demonstrate the actual rate of Lynch syndrome individuals identified from this initial screening.