Interactions between cells and their extracellular matrix have been shown to be crucial in a wide range of biological processes, including the proliferation and differentiation of stem cells. ...Ductular reactions containing both hepatic progenitor cells and extracellular matrix are seen in response to acute severe and chronic liver injury. Understanding the molecular mechanisms whereby cell-matrix interactions regulate liver regeneration may allow novel strategies to enhance this process. Both the ductular reaction in humans and hepatic progenitor cells in rodent models are closely associated with collagen and laminin, although there is still debate about cause and effect. Recent studies have shown a requirement for matrix remodeling by matrix metalloproteinases for the proliferation of hepatic progenitor cells and suggested defined roles for specific matrix components. Understanding the interactions between progenitor cells and matrix is critical for the development of novel regenerative and antifibrotic therapies.
Although nonalcoholic fatty liver disease (NAFLD) is conventionally assessed histologically for lobular features of inflammation, development of portal fibrosis appears to be associated with disease ...progression. We investigated the composition of the portal inflammatory infiltrate and its relationship to the ductular reaction (DR), a second portal phenomenon implicated in fibrogenesis. The portal inflammatory infiltrate may contribute directly to fibrogenesis as well as influence the fate of the DR hepatic progenitor cells (HPCs), regulating the balance between liver repair and fibrosis. The presence of portal inflammation in NAFLD was strongly correlated with disease severity (fibrosis stage) and the DR. The portal infiltrate was characterized by immunostaining NAFLD liver biopsy sections (n = 33) for broad leukocyte subset markers (CD68, CD3, CD8, CD4, CD20, and neutrophil elastase) and selected inflammatory markers (matrix metalloproteinase 9 and interleukin IL‐17). Cells expressing all markers examined were identified throughout the liver lobules and in portal tracts, although portal tracts were more densely populated (P < 0.01), and dominated by CD68+ macrophages and CD8+ lymphocytes, at all stages of disease. An increase in portal macrophages in NAFLD patients with steatosis alone (P < 0.01) was the earliest change detected, even before elevated expression of the proinflammatory cytokines, IL1B and TNF, in patients with early NASH (P < 0.05). Portal and periductal accumulation of all other cell types examined occurred in progressed NASH (all P < 0.05). Conclusion: Knowledge of the complex cellular composition of the portal inflammatory infiltrate and HPC/DR niche in NAFLD will shape future functional studies to elucidate the contribution of portal inflammation to HPC differentiation and NAFLD pathogenesis. (Hepatology 2014;59:1393‐1405)
Laparoscopic procedures are generally thought to have better outcomes than open procedures. Because of anatomical constraints, laparoscopic rectal resection may not be better because of limitations ...in performing an adequate cancer resection.
To determine whether laparoscopic resection is noninferior to open rectal cancer resection for adequacy of cancer clearance.
Randomized, noninferiority, phase 3 trial (Australasian Laparoscopic Cancer of the Rectum; ALaCaRT) conducted between March 2010 and November 2014. Twenty-six accredited surgeons from 24 sites in Australia and New Zealand randomized 475 patients with T1-T3 rectal adenocarcinoma less than 15 cm from the anal verge.
Open laparotomy and rectal resection (n = 237) or laparoscopic rectal resection (n = 238).
The primary end point was a composite of oncological factors indicating an adequate surgical resection, with a noninferiority boundary of Δ = -8%. Successful resection was defined as meeting all the following criteria: (1) complete total mesorectal excision, (2) a clear circumferential margin (≥1 mm), and (3) a clear distal resection margin (≥1 mm). Pathologists used standardized reporting and were blinded to the method of surgery.
A successful resection was achieved in 194 patients (82%) in the laparoscopic surgery group and 208 patients (89%) in the open surgery group (risk difference of -7.0% 95% CI, -12.4% to ∞; P = .38 for noninferiority). The circumferential resection margin was clear in 222 patients (93%) in the laparoscopic surgery group and in 228 patients (97%) in the open surgery group (risk difference of -3.7% 95% CI, -7.6% to 0.1%; P = .06), the distal margin was clear in 236 patients (99%) in the laparoscopic surgery group and in 234 patients (99%) in the open surgery group (risk difference of -0.4% 95% CI, -1.8% to 1.0%; P = .67), and total mesorectal excision was complete in 206 patients (87%) in the laparoscopic surgery group and 216 patients (92%) in the open surgery group (risk difference of -5.4% 95% CI, -10.9% to 0.2%; P = .06). The conversion rate from laparoscopic to open surgery was 9%.
Among patients with T1-T3 rectal tumors, noninferiority of laparoscopic surgery compared with open surgery for successful resection was not established. Although the overall quality of surgery was high, these findings do not provide sufficient evidence for the routine use of laparoscopic surgery. Longer follow-up of recurrence and survival is currently being acquired.
anzctr.org Identifier: ACTRN12609000663257.
Graft-versus-host disease (GVHD) in the gastrointestinal (GI) tract is the principal determinant of lethality following allogeneic bone marrow transplantation (BMT). Here, we examined the mechanisms ...that initiate GVHD, including the relevant antigen-presenting cells. MHC class II was expressed on intestinal epithelial cells (IECs) within the ileum at steady state but was absent from the IECs of germ-free mice. IEC-specific deletion of MHC class II prevented the initiation of lethal GVHD in the GI tract. MHC class II expression on IECs was absent from mice deficient in the TLR adaptors MyD88 and TRIF and required IFNγ secretion by lamina propria lymphocytes. IFNγ responses are characteristically driven by IL-12 secretion from myeloid cells. Antibiotic-mediated depletion of the microbiota inhibited IL-12/23p40 production by ileal macrophages. IL-12/23p40 neutralization prevented MHC class II upregulation on IECs and initiation of lethal GVHD in the GI tract. Thus, MHC class II expression by IECs in the ileum initiates lethal GVHD, and blockade of IL-12/23p40 may represent a readily translatable therapeutic strategy.
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•The microbiota influences MHC class II expression on IECs in the ileum•MHC class II expression on IECs requires an IL-12-IFNγ cytokine axis•MHC class II+ IECs present antigen, activate CD4+ T cells, and initiate lethal gut GVHD•IL-12/23p40 neutralization pretransplant prevents the initiation of lethal GVHD
Graft-versus-host disease in the gastrointestinal tract is the principal determinant of lethality following allogeneic bone marrow transplantation. Koyama et al. find that MHC class II-dependent antigen presentation by ileal intestinal epithelial cells (IECs) is critical for the initiation of lethal GVHD in the gut, define the requirements for IEC MHC class II expression, and propose IL-12 neutralization as a therapeutic strategy for GVHD.
The aim of the study was to determine the efficacy of laparoscopic rectal resection (Lap) versus open laparotomy and rectal resection (Open) for rectal cancer on locoregional recurrence (LRR) and ...disease-free survival (DFS) at 2 years.
Although a Lap approach to colon cancer surgery may offer similar oncological outcomes to Open with potentially less morbidity, this remains to be clearly established for the treatment of rectal cancer.
A randomized, multicenter noninferiority phase 3 trial of 475 patients with T1 to T3 rectal adenocarcinoma <15 cm from anal verge, given Lap or Open and followed for a minimum 2 years to assess LRR, DFS, and overall survival (OS).
Secondary endpoint analyses included 450 patients (95%) without metastases at baseline (mean age 64; 34% women) who received Lap (n = 225) or Open (n = 225). Median follow-up was 3.2 years (range: 0.1-5.4 yrs). LRR cumulative incidence at 2 years: Lap 5.4%; Open 3.1% difference, 2.3%; 95% confidence interval (CI), -1.5% to 6.1%; hazard ratio (HR) 1.7; 95% CI, 0.74-3.9. DFS at 2 years: Lap 80%; Open 82% (difference, 2.0%; 95% CI, -9.3% to 5.4%; HR for recurrence or death, 1.17; 95% CI, 0.81-1.68; P = 0.41). After adjustment for baseline factors HR = 1.07 (95% CI, 0.7-1.6). OS at 2 years: Lap 94%; Open 93% (difference 0.9%; 95% CI, -3.6% to 5.4%).
Laparoscopic surgery for rectal cancer did not differ significantly from open surgery in effects on 2-year recurrence or DFS and OS. Confidence intervals included potentially clinically important differences favoring open resection, so that the combination of primary and secondary study endpoints may not support laparoscopic resection of rectal cancer as a routine standard of care and further follow-up is required.
Histologically assessed hepatocyte ballooning is a key feature discriminating non-alcoholic steatohepatitis (NASH) from steatosis (NAFL). Reliable identification underpins patient inclusion in ...clinical trials and serves as a key regulatory-approved surrogate endpoint for drug efficacy. High inter/intra-observer variation in ballooning measured using the NASH CRN semi-quantitative score has been reported yet no actionable solutions have been proposed.
A focused evaluation of hepatocyte ballooning recognition was conducted. Digitized slides were evaluated by 9 internationally recognized expert liver pathologists on 2 separate occasions: each pathologist independently marked every ballooned hepatocyte and later provided an overall non-NASH NAFL/NASH assessment. Interobserver variation was assessed and a ‘concordance atlas’ of ballooned hepatocytes generated to train second harmonic generation/two-photon excitation fluorescence imaging-based artificial intelligence (AI).
The Fleiss kappa statistic for overall interobserver agreement for presence/absence of ballooning was 0.197 (95% CI 0.094–0.300), rising to 0.362 (0.258–0.465) with a ≥5-cell threshold. However, the intraclass correlation coefficient for consistency was higher (0.718 0.511–0.900), indicating ‘moderate’ agreement on ballooning burden. 133 ballooned cells were identified using a ≥5/9 majority to train AI ballooning detection (AI-pathologist pairwise concordance 19–42%, comparable to inter-pathologist pairwise concordance of between 8–75%). AI quantified change in ballooned cell burden in response to therapy in a separate slide set.
The substantial divergence in hepatocyte ballooning identified amongst expert hepatopathologists suggests that ballooning is a spectrum, too subjective for its presence or complete absence to be unequivocally determined as a trial endpoint. A concordance atlas may be used to train AI assistive technologies to reproducibly quantify ballooned hepatocytes that standardize assessment of therapeutic efficacy. This atlas serves as a reference standard for ongoing work to refine how ballooning is classified by both pathologists and AI.
For the first time, we show that, even amongst expert hepatopathologists, there is poor agreement regarding the number of ballooned hepatocytes seen on the same digitized histology images. This has important implications as the presence of ballooning is needed to establish the diagnosis of non-alcoholic steatohepatitis (NASH), and its unequivocal absence is one of the key requirements to show ‘NASH resolution’ to support drug efficacy in clinical trials. Artificial intelligence-based approaches may provide a more reliable way to assess the range of injury recorded as “hepatocyte ballooning”.
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•Hepatocyte ballooning identification underpins regulatory-approved drug efficacy endpoints in clinical trials.•We report substantial variation in ballooned cell identification by expert hepatopathologists.•Our data suggest that ballooning is too subjective for its presence or complete absence to be used as a trial endpoint.•A ‘concordance atlas’ of cells identified as ballooned by multiple pathologists can be used to train AI-based image analysis.•AI-based approaches may provide a more reliable way to assess the range of injury recorded as hepatocyte ballooning.
Interest in hepatic ductular reactions (DRs) has risen in recent years because of a greater appreciation of their potential roles in regeneration, fibrogenesis, and carcinogenesis. However, confusion ...exists because there is significant, but often unappreciated diversity at the tissue, cellular, and subcellular levels in DRs of different diseases and stages of disease. DRs are encountered in virtually all liver disorders in which there is organ‐wide liver damage and cell loss, but are also present in focal lesions such as focal nodular hyperplasia and adenoma. Moreover, diverse DR phenotypes can be present within any single disease entity, and are shaped by the etiology and evolution of the disease. Although much remains to be clarified, recent studies suggest that the diversity of appearances of the DRs are likely to reflect the differing signals at the anatomic, cellular, and molecular levels driving the proliferative response. These appear to determine the relative proportions of transit‐amplifying cells, the degree of hepatocytic or cholangiocytic differentiation, and their relationships with stromal, vascular, and inflammatory components. The molecular signaling pathways governing these regenerative fate decisions closely replicate those found in human and other vertebrate embryos and more generally in stem cell niches throughout the body. Like the latter, complex interactions with matrix as well as mesenchymal and inflammatory cells, vessels, and innervation are likely to be of fundamental importance. Embracing systems/tissue biological approaches to exploring DRs, in addition to more traditional cellular and molecular biological techniques, will further enhance our understanding and, thereby, we believe potentiate new therapeutic possibilities. (HEPATOLOGY 2011)
Steatosis: co-factor in other liver diseases Powell, Elizabeth E; Jonsson, Julie R; Clouston, Andrew D
Hepatology (Baltimore, Md.),
07/2005, Letnik:
42, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The prevalence of fatty liver is rising in association with the global increase in obesity and type 2 diabetes. In the past, simple steatosis was regarded as benign, but the presence of another liver ...disease may provide a synergistic combination of steatosis, cellular adaptation, and oxidative damage that aggravates liver injury. In this review, a major focus is on the role of steatosis as a co-factor in chronic hepatitis C (HCV), where the mechanisms promoting fibrosis and the effect of weight reduction in minimizing liver injury have been most widely studied. Steatosis, obesity, and associated metabolic factors may also modulate the response to alcohol- and drug-induced liver disease and may be risk factors for the development of hepatocellular cancer. The pathogenesis of injury in obesity-related fatty liver disease involves a number of pathways, which are currently under investigation. Enhanced oxidative stress, increased susceptibility to apoptosis, and a dysregulated response to cellular injury have been implicated, and other components of the metabolic syndrome such as hyperinsulinemia and hyperglycemia are likely to have a role. Fibrosis also may be increased as a by-product of altered hepatocyte regeneration and activation of bipotential hepatic progenitor cells. In conclusion, active management of obesity and a reduction in steatosis may improve liver injury and decrease the progression of fibrosis.
Graft-versus-host disease (GVHD) after allogeneic stem cell transplantation (alloSCT) is characterized by interleukin-6 (IL-6) dysregulation. IL-6 can mediate effects via various pathways, including ...classical, trans, and cluster signaling. Given the recent availability of agents that differentially inhibit these discrete signaling cascades, understanding the source and signaling and cellular targets of this cytokine is paramount to inform the design of clinical studies. Here we demonstrate that IL-6 secretion from recipient dendritic cells (DCs) initiates the systemic dysregulation of this cytokine. Inhibition of DC-driven classical signaling after targeted IL-6 receptor (IL-6R) deletion in T cells eliminated pathogenic donor Th17/Th22 cell differentiation and resulted in long-term survival. After engraftment, donor DCs assume the same role, maintaining classical IL-6 signaling–dependent GVHD responses. Surprisingly, cluster signaling was not active after transplantation, whereas inhibition of trans signaling with soluble gp130Fc promoted severe, chronic cutaneous GVHD. The latter was a result of exaggerated polyfunctional Th22-cell expansion that was reversed by IL-22 deletion or IL-6R inhibition. Importantly, inhibition of IL-6 classical signaling did not impair the graft-versus-leukemia effect. Together, these data highlight IL-6 classical signaling and downstream Th17/Th22 differentiation as important therapeutic targets after alloSCT.
•DCs are the principal source of IL-6 dysregulation after alloSCT.•IL-6–dependent GVHD is driven by classical signaling of IL-6R on donor T cells but is regulated by trans signaling.
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The traditional serrated adenoma is the least common colorectal serrated polyp. The clinicopathological features and molecular drivers of these polyps require further investigation. We have ...prospectively collected a cohort of 200 ordinary and advanced traditional serrated adenomas and performed BRAF and KRAS mutational profiling, CpG island methylator phenotype analysis, and immunohistochemistry for a panel of 7 antibodies (MLH1, β-catenin, p53, p16, Ki67, CK7, and CK20) on all cases. The mean age of the patients was 64 years and 50% were female. Of the polyps, 71% were distal. Advanced histology (overt dysplasia or carcinoma) was present in 19% of cases. BRAF mutation was present in 67% and KRAS mutation in 22%. BRAF mutant traditional serrated adenomas were more frequently proximal (39% versus 2%; P≤0.0001), were exclusively associated with a precursor polyp (57% versus 0%; P≤0.0001), and were more frequently CpG island methylator phenotype high (60% versus 16%; P≤0.0001) than KRAS mutant traditional serrated adenomas. Advanced traditional serrated adenomas retained MLH1 expression in 97%, showed strong p53 staining in 55%, and nuclear β-catenin staining in 40%. P16 staining was lost in the advanced areas of 55% of BRAF mutant traditional serrated adenomas compared with 10% of the advanced areas of KRAS mutant or BRAF/KRAS wild-type traditional serrated adenomas. BRAF and KRAS mutant traditional serrated adenomas are morphologically related but biologically disparate polyps with distinctive clinicopathological and molecular features. The overwhelming majority of traditional serrated adenomas retain mismatch repair enzyme function indicating a microsatellite-stable phenotype. Malignant progression occurs via TP53 mutation and Wnt pathway activation regardless of mutation status. However, CDKN2A (encoding the p16 protein) is silenced nearly exclusively in the advanced areas of the BRAF mutant traditional serrated adenomas. Thus, the BRAF mutant traditional serrated adenoma represents an important precursor of the aggressive BRAF mutant, microsatellite-stable subtype of colorectal carcinoma.
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