Assessment of inter-centre agreement across multidisciplinary team meetings for patients with retroperitoneal sarcoma.

BACKGROUND: Decision-making in the management of patients with retroperitoneal sarcoma is complex and requires input from a number of different specialists. The aim of this study was to evaluate the levels of agreement in terms of resectability, treatment allocation, and organs proposed to be resected across different retroperitoneal sarcoma multidisciplinary team meetings. METHODS: The CT scans and clinical information of 21 anonymized retroperitoneal sarcoma patients were sent to all of the retroperitoneal sarcoma multidisciplinary team meetings in Great Britain, which were asked to give an opinion about resectability, treatment allocation, and organs proposed to be resected. The main outcome was inter-centre reliability, which was quantified using overall agreement, as well as the chance-corrected Krippendorff's alpha statistic. Based on the latter, the level of agreement was classified as: 'slight' (0.00-0.20), 'fair' (0.21-0.40), 'moderate' (0.41-0.60), 'substantial' (0.61-0.80), or 'near-perfect' (>0.80). RESULTS: Twenty-one patients were reviewed at 12 retroperitoneal sarcoma multidisciplinary team meetings, giving a total of 252 assessments for analysis. Consistency between centres was only 'slight' to 'fair', with rates of overall agreement and Krippendorff's alpha statistics of 85.4 per cent (211 of 247) and 0.37 (95 per cent c.i. 0.11 to 0.57) for resectability; 80.4 per cent (201 of 250) and 0.39 (95 per cent c.i. 0.33 to 0.45) for treatment allocation; and 53.0 per cent (131 of 247) and 0.20 (95 per cent c.i. 0.17 to 0.23) for the organs proposed to be resected. Depending on the centre that they had attended, 12 of 21 patients could either have been deemed resectable or unresectable, and 10 of 21 could have received either potentially curative or palliative treatment. CONCLUSIONS: Inter-centre agreement between retroperitoneal sarcoma multidisciplinary team meetings was low. Multidisciplinary team meetings may not provide the same standard of care for patients with retroperitoneal sarcoma across Great Britain.

A Mammalian Target of Rapamycin-Perilipin 3 (mTORC1-Plin3) Pathway is essential to Activate Lipophagy and Protects Against Hepatosteatosis.

BACKGROUND AND AIMS: NAFLD is the most common hepatic pathology in western countries and no treatment is currently available. NAFLD is characterized by the aberrant hepatocellular accumulation of fatty acids in the form of lipid droplets (LDs). Recently, it was shown that liver LD degradation occurs through a process termed lipophagy, a form of autophagy. However, the molecular mechanisms governing liver lipophagy are elusive. Here, we aimed to ascertain the key molecular players that regulate hepatic lipophagy and their importance in NAFLD. APPROACH AND RESULTS: We analyzed the formation and degradation of LD in vitro (fibroblasts and primary mouse hepatocytes), in vivo and ex vivo (mouse and human liver slices) and focused on the role of the autophagy master regulator mammalian target of rapamycin complex (mTORC) 1 and the LD coating protein perilipin (Plin) 3 in these processes. We show that the autophagy machinery is recruited to the LD on hepatic overload of oleic acid in all experimental settings. This led to activation of lipophagy, a process that was abolished by Plin3 knockdown using RNA interference. Furthermore, Plin3 directly interacted with the autophagy proteins focal adhesion interaction protein 200 KDa and autophagy-related 16L, suggesting that Plin3 functions as a docking protein or is involved in autophagosome formation to activate lipophagy. Finally, we show that mTORC1 phosphorylated Plin3 to promote LD degradation. CONCLUSIONS: These results reveal that mTORC1 regulates liver lipophagy through a mechanism dependent on Plin3 phosphorylation. We propose that stimulating this pathway can enhance lipophagy in hepatocytes to help protect the liver from lipid-mediated toxicity, thus offering a therapeutic strategy in NAFLD.

Comparative analysis of open, laparoscopic and robotic distal pancreatic resection: The United Kingdom's first single-centre experience.

INTRODUCTION: Laparoscopic distal pancreatectomy (LDP) has potential advantages over its open equivalent open distal pancreatectomy (ODP) for pancreatic disease in the neck, body and tail. Within the United Kingdom (UK), there has been no previous experience describing the role of robotic distal pancreatectomy (RDP). This study evaluated differences between ODP, LDP and RDP. METHODS: Patients undergoing distal pancreatectomy performed in the Department of Hepatobiliary and Pancreatic Surgery at the Freeman Hospital between September 2007 and December 2018 were included from a prospectively maintained database. The primary outcome measure was length of hospital stay, and the secondary outcome measures were complication rates graded according to the Clavien-Dindo classification. RESULTS: Of the 125 patients, the median age was 61 years and 46% were male. Patients undergoing RDP (n = 40) had higher American Society of Anesthesiologists grading III compared to ODP (n = 38) and LDP (n = 47) (57% vs. 37% vs. 38%, P = 0.02). RDP had a slightly lower but not significant conversion rate (10% vs. 13%, P = 0.084), less blood loss (median: 0 vs. 250 ml, P < 0.001) and a higher rate of splenic preservation (30% vs. 2%, P < 0.001) and shorter operative time, once docking time excluded (284 vs. 300 min, P < 0.001) compared to LDP. RDP had a higher R0 resection rate than ODP and LDP (79% vs. 47% vs. 71%, P = 0.078) for neoplasms. RDP was associated with significantly shorter hospital stay than LDP and ODP (8 vs. 9 vs. 10 days, P = 0.001). While there was no significant different in overall complications across the groups, RDP was associated with lower rates of Grade C pancreatic fistula than ODP and LDP (2% vs. 5% vs. 6%, P = 0.194). CONCLUSION: Minimally invasive pancreatic resection offers potential advantages over ODP, with a trend showing RDP to be marginally superior when compared to conventional LDP, but it is accepted that that this is likely to be at greater expense compared to the other current techniques.

Epigenetic mechanisms and metabolic reprogramming in fibrogenesis: dual targeting of G9a and DNMT1 for the inhibition of liver fibrosis.

OBJECTIVE: Hepatic stellate cells (HSC) transdifferentiation into myofibroblasts is central to fibrogenesis. Epigenetic mechanisms, including histone and DNA methylation, play a key role in this process. Concerted action between histone and DNA-mehyltransferases like G9a and DNMT1 is a common theme in gene expression regulation. We aimed to study the efficacy of CM272, a first-in-class dual and reversible G9a/DNMT1 inhibitor, in halting fibrogenesis. DESIGN: G9a and DNMT1 were analysed in cirrhotic human livers, mouse models of liver fibrosis and cultured mouse HSC. G9a and DNMT1 expression was knocked down or inhibited with CM272 in human HSC (hHSC), and transcriptomic responses to transforming growth factor-ß1 (TGFß1) were examined. Glycolytic metabolism and mitochondrial function were analysed with Seahorse-XF technology. Gene expression regulation was analysed by chromatin immunoprecipitation and methylation-specific PCR. Antifibrogenic activity and safety of CM272 were studied in mouse chronic CCl4 administration and bile duct ligation (BDL), and in human precision-cut liver slices (PCLSs) in a new bioreactor technology. RESULTS: G9a and DNMT1 were detected in stromal cells in areas of active fibrosis in human and mouse livers. G9a and DNMT1 expression was induced during mouse HSC activation, and TGFß1 triggered their chromatin recruitment in hHSC. G9a/DNMT1 knockdown and CM272 inhibited TGFß1 fibrogenic responses in hHSC. TGFß1-mediated profibrogenic metabolic reprogramming was abrogated by CM272, which restored gluconeogenic gene expression and mitochondrial function through on-target epigenetic effects. CM272 inhibited fibrogenesis in mice and PCLSs without toxicity. CONCLUSIONS: Dual G9a/DNMT1 inhibition by compounds like CM272 may be a novel therapeutic strategy for treating liver fibrosis.

Endoscopic transmural drainage is associated with improved outcomes in disconnected pancreatic duct syndrome: a systematic review and meta-analysis.

BACKGROUND: Disconnected pancreatic duct syndrome (DPDS) is a complication of acute necrotizing pancreatitis in the neck and body of the pancreas often manifesting as persistent pancreatic fluid collection (PFC) or external pancreatic fistula (EPF). This systematic review and pairwise meta-analysis aimed to review the definitions, clinical presentation, intervention, and outcomes for DPDS. METHODS: The PubMed, EMBASE, MEDLINE, and SCOPUS databases were systematically searched until February 2020 using the PRISMA framework. A meta-analysis was performed to assess the success rates of endoscopic and surgical interventions for the treatment of DPDS. Success of DPDS treatment was defined as long-term resolution of symptoms without recurrence of PFC, EPF, or pancreatic ascites. RESULTS: Thirty studies were included in the quantitative analysis comprising 1355 patients. Acute pancreatitis was the most common etiology (95.3%, 936/982), followed by chronic pancreatitis (3.1%, 30/982). DPDS commonly presented with PFC (83.2%, 948/1140) and EPF (13.4%, 153/1140). There was significant heterogeneity in the definition of DPDS in the literature. Weighted success rate of endoscopic transmural drainage (90.6%, 95%-CI 81.0-95.6%) was significantly higher than transpapillary drainage (58.5%, 95%-CI 36.7-77.4). Pairwise meta-analysis showed comparable success rates between endoscopic and surgical intervention, which were 82% (weighted 95%-CI 68.6-90.5) and 87.4% (95%-CI 81.2-91.8), respectively (P = 0.389). CONCLUSIONS: Endoscopic transmural drainage was superior to transpapillary drainage for the management of DPDS. Endoscopic and surgical interventions had comparable success rates. The significant variability in the definitions and treatment strategies for DPDS warrant standardisation for further research.

Systematic review and meta-analysis of risk factors of postoperative pancreatic fistula after distal pancreatectomy in the era of 2016 International Study Group pancreatic fistula definition.

BACKGROUND: Risk factors for the development of clinically relevant POPF (CR-POPF) following distal pancreatectomy (DP) need clarification particularly following the 2016 International Study Group of Pancreatic Fistula (ISGPF) definition. METHODS: A systemic search of MEDLINE, Pubmed, Scopus, and EMBASE were conducted using the PRISMA framework. Studies were evaluated for risk factors for the development CR-POPF after DP using the 2016 ISGPF definition. Further subgroup analysis was undertaken on studies ≥10 patients in exposed and non-exposed subgroups. RESULTS: Forty-three studies with 8864 patients were included in the meta-analysis. The weighted rate of CR-POPF was 20.4% (95%-CI: 17.7-23.4%). Smoking (OR 1.29, 95%-CI: 1.08-1.53, p = 0.02) and open DP (OR 1.43, 95%-CI: 1.02-2.01, p = 0.04) were found to be significant risk factors of CR-POPF. Diabetes (OR 0.81, 95%-CI: 0.68-0.95, p = 0.02) was a significant protective factor against CR-POPF. Substantial heterogeneity was observed in the comparisons of pancreatic texture and body mass index. Seventeen risk factors achieved significance in a univariate or multivariate comparison as reported by individual studies in the narrative synthesis, however, they remain difficult to interpret as statistically significant comparisons were not uniform. CONCLUSION: This meta-analysis found smoking and open DP to be risk factors and diabetes to be protective factor of CR-POPF in the era of 2016 ISGPF definition.

A Bioreactor Technology for Modeling Fibrosis in Human and Rodent Precision-Cut Liver Slices.

Precision cut liver slices (PCLSs) retain the structure and cellular composition of the native liver and represent an improved system to study liver fibrosis compared to two-dimensional mono- or co-cultures. The aim of this study was to develop a bioreactor system to increase the healthy life span of PCLSs and model fibrogenesis. PCLSs were generated from normal rat or human liver, or fibrotic rat liver, and cultured in our bioreactor. PCLS function was quantified by albumin enzyme-linked immunosorbent assay (ELISA). Fibrosis was induced in PCLSs by transforming growth factor beta 1 (TGFß1) and platelet-derived growth factor (PDGFßß) stimulation ± therapy. Fibrosis was assessed by gene expression, picrosirius red, and α-smooth muscle actin staining, hydroxyproline assay, and soluble ELISAs. Bioreactor-cultured PCLSs are viable, maintaining tissue structure, metabolic activity, and stable albumin secretion for up to 6 days under normoxic culture conditions. Conversely, standard static transwell-cultured PCLSs rapidly deteriorate, and albumin secretion is significantly impaired by 48 hours. TGFß1/PDGFßß stimulation of rat or human PCLSs induced fibrogenic gene expression, release of extracellular matrix proteins, activation of hepatic myofibroblasts, and histological fibrosis. Fibrogenesis slowly progresses over 6 days in cultured fibrotic rat PCLSs without exogenous challenge. Activin receptor-like kinase 5 (Alk5) inhibitor (Alk5i), nintedanib, and obeticholic acid therapy limited fibrogenesis in TGFß1/PDGFßß-stimulated PCLSs, and Alk5i blunted progression of fibrosis in fibrotic PCLS. Conclusion: We describe a bioreactor technology that maintains functional PCLS cultures for 6 days. Bioreactor-cultured PCLSs can be successfully used to model fibrogenesis and demonstrate efficacy of antifibrotic therapies.

Meta-Analysis and Meta-Regression of Risk Factors for Surgical Site Infections in Hepatic and Pancreatic Resection.

BACKGROUND: The risk factors for surgical site infection (SSI) after HPB surgery are poorly defined. This meta-analysis aimed to quantify the SSI rates and risk factors for SSI after pancreas and liver resection. METHODS: The PUBMED, MEDLINE and EMBASE databases were systematically searched using the PRISMA framework. The primary outcome measure was pooled SSI rates. The secondary outcome measure was risk factor profile determination for SSI. RESULTS: The overall rate of SSI after pancreatic and liver resection was 25.1 and 10.4%, respectively (p < 0.001). 32% of pancreaticoduodenectomies developed SSI vs 23% after distal pancreatectomy (p < 0.001). The rate of incisional SSI in the pancreatic group was 9% and organ/space SSI 16.5%. Biliary resection during liver surgery was a risk factor for SSI (25.0 vs 15.7%, p = 0.002). After liver resection, the incisional SSI rate was 7.6% and the organ space SSI rate was 10.2%. Pancreas-specific SSI risk factors were pre-operative biliary drainage (p < 0.001), chemotherapy (p < 0.001) and radiotherapy (p = 0.007). Liver-specific SSI risk factors were smoking (p = 0.046), low albumin (p < 0.001) and significant blood loss (p < 0.001). The rate of organ/space SSI in patients with POPF was 47.7% and in patients without POPF 7.3% (p < 0.001). Organ/space SSI rate was 43% in patients with bile leak and 10% in those without (p < 0.001). CONCLUSIONS: The risk factors for SSI following pancreatic and liver resections are distinct from each other, with higher SSI rates after pancreatic resection. Pancreaticoduodenectomy has increased risk of SSI compared to distal pancreatectomy. Similarly, biliary resections during liver surgery increase the rates of SSI.

A Systematic Review and Network-Meta-Analysis of Gastro-Enteric Reconstruction Techniques Following Pancreatoduodenectomy to Reduce Delayed Gastric Emptying.

INTRODUCTION: This network meta-analysis aimed to identify the reconstruction technique associated with lowest rates of DGE following pancreatoduodenectomy (PD) from randomised controlled trials (RCTs). METHODS: A systematic literature search of PubMed, Embase and MEDLINE databases was carried out using the PRISMA framework to identify all RCTs comparing reconstruction techniques of gastrojejunostomy after PD, with overall DGE as the primary endpoint. The primary outcome measure was overall DGE. Secondary outcomes were grade B/C DGE, duration of nasogastric tube, time to solid food intake, overall and grade B/C pancreatic fistula, bile leaks, reoperation, length of hospital stay and in-hospital mortality. RESULTS: The search strategy identified eight RCTs including 761 patients. Six RCTs compared antecolic (n = 291 patients) and retrocolic Billroth II (n = 289 patients) reconstruction (n = 6 studies), and two RCTs compared antecolic Billroth II (n = 92 patients) and Roux-en-Y (n = 89 patients) reconstruction. Overall, antecolic Billroth II ranked best for overall and grade B/C DGE, bile leak, surgical site infection, length of stay and in-hospital mortality. Roux-en-Y was best for overall and grade B/C pancreatic fistula. CONCLUSION: Antecolic Billroth II gastroenteric reconstruction is associated with the lowest rates of delayed gastric emptying after PD amongst the currently available techniques of gastrojejunostomy reconstructions.

Haemostatic Efficacy of Topical Agents During Liver Resection: A Network Meta-Analysis of Randomised Trials.

BACKGROUND: Hepatic resection carries a high risk of parenchymal bleeding both intra- and post-operatively. Topical haemostatic agents are frequently used to control bleeding during hepatectomy, with multiple products currently available. However, it remains unknown which of these is most effective for achieving haemostasis and improving peri-operative outcomes. METHODS: A systematic review and random-effects Bayesian network meta-analysis of randomised trials investigating topical haemostatic agents in hepatic resection was performed. Interventions were analysed by grouping into similar products; fibrin patch, fibrin glue, collagen products, and control. Primary outcomes were the rate of haemostasis at 4 and 10 min. RESULTS: Twenty randomized controlled trials were included in the network meta-analysis, including a total of 3267 patients and 7 different interventions. Fibrin glue and fibrin patch were the most effective interventions for achieving haemostasis at both 4 and 10 min. There were no significant differences between haemostatic agents with respect to blood loss, transfusion requirements, bile leak, post-operative complications, reoperation, or mortality. CONCLUSIONS: Amongst the haemostatic agents currently available, fibrin patch and fibrin glue are the most effective methods for reducing time to haemostasis during liver resection, but have no effect on other peri-operative outcomes. Topical haemostatic agents should not be used routinely, but may be a useful adjunct to achieve haemostasis when needed.

A systematic review and network meta-analysis of parenchymal transection techniques during hepatectomy: an appraisal of current randomised controlled trials.

BACKGROUND: Major liver resection can lead to significant morbidity and mortality. Blood loss is one of the most important factors predicting a good outcome. Although various transection methods have been reported, there is no consensus on the best technique. This systematic review and network meta-analysis aims to characterise and identify the best reported technique for elective parenchymal liver transection based on published randomised controlled trials (RCT's). METHODS: A systematic review was conducted using MEDLINE, EMBASE, and Cochrane Central to identify RCT's up to 5th June 2019 that examined parenchymal transection for liver resection. Data including study characteristics and outcomes including intraoperative (blood loss, operating time) and postoperative measures (overall and major complications, bile leaks) were extracted. Indirect comparisons of all regimens were simultaneously compared using random-effects network meta-analyses (NMA) which maintains randomisation within trials. RESULTS: This study identified 22 RCT's involving 2360 patients reporting ten parenchymal transection techniques. Bipolar cautery has lower blood loss and shorter operating time than stapler (mean difference: 85 mL; 22min) and Tissue Link (mean difference: 66 mL; 29min). Bipolar cautery was ranked first for blood loss and operating time followed by stapler and TissueLink. Harmonic scalpel is associated with lower overall complications than Hydrojet (Odds ratio (OR): 0.48), BiClamp forceps (OR: 0.46) and clamp crushing (OR: 0.41). CONCLUSION: Bipolar cautery techniques appear to best at reducing blood loss and associated with shortest operating time. In contrast, Harmonic scalpel appears best for overall and major complications. Given the paucity of data and selective outcome reporting, it is still hard to identify what is the best technique for liver resection. Therefore, further high-quality large-scale RCT's are still needed.

The association of pregnane X receptor activation with outcomes after liver transplantation-A retrospective study.

BACKGROUND: Many complications following liver transplantation are linked to ischemia-reperfusion injury. Activation of the pregnane X receptor (PXR) has been shown to alleviate this process in animal models. The aim of this retrospective study was to investigate the effect of early activation of human PXR (hPXR) on postoperative complications and survival following liver transplantation. METHODS: The study included deceased donor liver transplants at a single center over 6 years. Estimated hPXR activation value on day 7 (EPAV7 ) was calculated per patient based on potency/total dose of known hPXR-activating drugs administered in the first week post-transplantation. Patients were divided into low and high hPXR activation groups based on EPAV7 . RESULTS: Overall, 240 liver transplants were included. Average EPAV7 was significantly lower in patients who developed anastomotic biliary strictures (17.7 ± 5.5 vs 35.1 ± 5.7 in stricture-free patients; P = .03) and sepsis (16.4 ± 7.1 vs 34.9 ± 5.5; P = .04). Patient survival was significantly improved in the high hPXR group (5-year survival: 88.7% ± 3.8% versus 70.7% ± 5.8% [low hPXR]; P = .023). Regression analysis identified EPAV7 as a significant independent predictor of patient survival. CONCLUSION: hPXR activation within the first week of liver transplantation is a prognostic indicator of patient survival, possibly due to the associated lower biliary stricture and infection rates.

Robotic versus conventional laparoscopic distal pancreatic resection: a systematic review and meta-analysis.

BACKGROUND: Robotic surgery offers theoretical advantages to conventional laparoscopic surgery including improved instrument dexterity, 3D visualization and better ergonomics. This review aimed to determine if these theoretical advantages translate into improved patient outcomes in patients undergoing distal pancreatectomy through laparoscopic (LDP) or robotic (RDP) approaches. METHOD: A systematic literature search was conducted for studies reporting minimally invasive surgery for distal pancreatectomy. Meta-analysis of intraoperative (blood loss, operating times, conversion and R0 resections) and postoperative outcomes (overall complications, pancreatic fistula, length of hospital stay) was performed using random effects models. RESULT: Twenty non-randomised studies including 3112 patients (793 robotic and 2319 laparoscopic) were considered appropriate for inclusion. LDP had significantly shorter operating time than RDP (mean: 28, p < 0.001) but no significant difference in blood loss (mean: 52 mL, p = 0.07). RDP was associated with significantly lower conversion rates than LDP (OR 0.48, p < 0.001), but no difference in spleen preservation rate and R0 resection. There were no significant differences in overall and major complications, overall and high-grade pancreatic fistula. However, RDP was associated with a shorter length of hospital stay (mean: 1, p < 0.001). CONCLUSION: Robotic distal pancreatectomy appears to offer some advantages compared to conventional laparoscopic surgery, although both techniques appear equivalent. Importantly, the quality of evidence is generally limited to cohort studies and a high-quality randomised trial comparing both techniques are needed.

Minimally invasive and endoscopic versus open necrosectomy for necrotising pancreatitis: a pooled analysis of individual data for 1980 patients.

OBJECTIVE: Minimally invasive surgical necrosectomy and endoscopic necrosectomy, compared with open necrosectomy, might improve outcomes in necrotising pancreatitis, especially in critically ill patients. Evidence from large comparative studies is lacking. DESIGN: We combined original and newly collected data from 15 published and unpublished patient cohorts (51 hospitals; 8 countries) on pancreatic necrosectomy for necrotising pancreatitis. Death rates were compared in patients undergoing open necrosectomy versus minimally invasive surgical or endoscopic necrosectomy. To adjust for confounding and to study effect modification by clinical severity, we performed two types of analyses: logistic multivariable regression and propensity score matching with stratification according to predicted risk of death at baseline (low: <5%; intermediate: ≥5% to <15%; high: ≥15% to <35%; and very high: ≥35%). RESULTS: Among 1980 patients with necrotising pancreatitis, 1167 underwent open necrosectomy and 813 underwent minimally invasive surgical (n=467) or endoscopic (n=346) necrosectomy. There was a lower risk of death for minimally invasive surgical necrosectomy (OR, 0.53; 95% CI 0.34 to 0.84; p=0.006) and endoscopic necrosectomy (OR, 0.20; 95% CI 0.06 to 0.63; p=0.006). After propensity score matching with risk stratification, minimally invasive surgical necrosectomy remained associated with a lower risk of death than open necrosectomy in the very high-risk group (42/111 vs 59/111; risk ratio, 0.70; 95% CI 0.52 to 0.95; p=0.02). Endoscopic necrosectomy was associated with a lower risk of death than open necrosectomy in the high-risk group (3/40 vs 12/40; risk ratio, 0.27; 95% CI 0.08 to 0.88; p=0.03) and in the very high-risk group (12/57 vs 28/57; risk ratio, 0.43; 95% CI 0.24 to 0.77; p=0.005). CONCLUSION: In high-risk patients with necrotising pancreatitis, minimally invasive surgical and endoscopic necrosectomy are associated with reduced death rates compared with open necrosectomy.

Plasma DNA methylation: a potential biomarker for stratification of liver fibrosis in non-alcoholic fatty liver disease.

OBJECTIVE: Liver biopsy is currently the most reliable way of evaluating liver fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). Its inherent risks limit its widespread use. Differential liver DNA methylation of peroxisome proliferator-activated receptor gamma (PPARγ) gene promoter has recently been shown to stratify patients in terms of fibrosis severity but requires access to liver tissue. The aim of this study was to assess whether DNA methylation of circulating DNA could be detected in human plasma and potentially used to stratify liver fibrosis severity in patients with NAFLD. DESIGN: Patients with biopsy-proven NAFLD and age-matched controls were recruited from the liver and gastroenterology clinics at the Newcastle upon Tyne Hospitals NHS Foundation Trust. Plasma cell-free circulating DNA methylation of PPARγ was quantitatively assessed by pyrosequencing. Liver DNA methylation was quantitatively assessed by pyrosequencing NAFLD explant tissue, subjected to laser capture microdissection (LCM). Patients with alcoholic liver disease (ALD) were also subjected to plasma DNA and LCM pyrosequencing. RESULTS: 26 patients with biopsy-proven NAFLD were included. Quantitative plasma DNA methylation of PPARγ stratified patients into mild (Kleiner 1-2) and severe (Kleiner 3-4) fibrosis (CpG1: 63% vs 86%, p<0.05; CpG2: 51% vs 65% p>0.05). Hypermethylation at the PPARγ promoter of plasma DNA correlated with changes in hepatocellular rather than myofibroblast DNA methylation. Similar results were demonstrated in patients with ALD cirrhosis. CONCLUSIONS: Differential DNA methylation at the PPARγ promoter can be detected within the pool of cell-free DNA of human plasma. With further validation, plasma DNA methylation of PPARγ could potentially be used to non-invasively stratify liver fibrosis severity in patients with NAFLD. Plasma DNA methylation signatures reflect the molecular pathology associated with fibrotic liver disease.

Hepatic stellate cell transdifferentiation involves genome-wide remodeling of the DNA methylation landscape.

BACKGROUND & AIMS: DNA methylation (5-mC) is an epigenetic mark that is an established regulator of transcriptional repression with an important role in liver fibrosis. Currently, there is very little knowledge available as to how DNA methylation controls the phenotype of hepatic stellate cell (HSC), the key cell type responsible for onset and progression of liver fibrosis. Moreover, recently discovered DNA hydroxymethylation (5-hmC) is involved in transcriptional activation and its patterns are often altered in human diseases. The aim of this study is to investigate the role of DNA methylation/hydroxymethylation in liver fibrosis. METHODS: Levels of 5-mC and 5-hmC were assessed by slot blot in a range of animal liver fibrosis models and human liver diseases. Expression levels of TET and DNMT enzymes were measured by qRT-PCR and Western blotting. Reduced representation bisulfite sequencing (RRBS) method was used to examine 5-mC and 5-hmC patterns in quiescent and in vivo activated rat HSC. RESULTS: We demonstrate global alteration in 5-mC and 5-hmC and their regulatory enzymes that accompany liver fibrosis and HSC transdifferentiation. Using RRBS, we show exact genomic positions of changed methylation patterns in quiescent and in vivo activated rat HSC. In addition, we demonstrate that reduction in DNMT3a expression leads to attenuation of pro-fibrogenic phenotype in activated HSC. CONCLUSIONS: Our data suggest that DNA 5-mC/5-hmC is a crucial step in HSC activation and therefore fibrogenesis. Changes in DNA methylation during HSC activation may bring new insights into the molecular events underpinning fibrogenesis and may provide biomarkers for disease progression as well as potential new drug targets.

Alcohol directly stimulates epigenetic modifications in hepatic stellate cells.

BACKGROUND & AIMS: Alcohol is a primary cause of liver disease and an important co-morbidity factor in other causes of liver disease. A common feature of progressive liver disease is fibrosis, which results from the net deposition of fibril-forming extracellular matrix (ECM). The hepatic stellate cell (HSC) is widely considered to be the major cellular source of fibrotic ECM. We determined if HSCs are responsive to direct stimulation by alcohol. METHODS: HSCs undergoing transdifferentiation were incubated with ethanol and expression of fibrogenic genes and epigenetic regulators was measured. Mechanisms responsible for recorded changes were investigated using ChIP-Seq and bioinformatics analysis. Ethanol induced changes were confirmed using HSCs isolated from a mouse alcohol model and from ALD patient's liver and through precision cut liver slices. RESULTS: HSCs responded to ethanol exposure by increasing profibrogenic and ECM gene expression including elastin. Ethanol induced an altered expression of multiple epigenetic regulators, indicative of a potential to modulate chromatin structure during HSC transdifferentiation. MLL1, a histone 3 lysine 4 (H3K4) methyltransferase, was induced by ethanol and recruited to the elastin gene promoter where it was associated with enriched H3K4me3, a mark of active chromatin. Chromatin immunoprecipitation sequencing (ChIPseq) revealed that ethanol has broad effects on the HSC epigenome and identified 41 gene loci at which both MML1 and its H3K4me3 mark were enriched in response to ethanol. CONCLUSIONS: Ethanol directly influences HSC transdifferentiation by stimulating global changes in chromatin structure, resulting in the increased expression of ECM proteins. The ability of alcohol to remodel the epigenome during HSC transdifferentiation provides mechanisms for it to act as a co-morbidity factor in liver disease.

Ubiquitin C-terminal hydrolase 1: A novel functional marker for liver myofibroblasts and a therapeutic target in chronic liver disease.

BACKGROUND & AIMS: Ubiquitination is a reversible protein modification involved in the major cellular processes that define cell phenotype and behaviour. Ubiquitin modifications are removed by a large family of proteases named deubiquitinases. The role of deubiquitinases in hepatic stellate cell (HSC) activation and their contribution to fibrogenesis are poorly defined. We have identified that the deubiquitinase ubiquitin C-terminal hydrolase 1 (UCHL1) is highly induced following HSC activation, determined its function in activated HSC and its potential as a therapeutic target for fibrosis. METHODS: Deubiquitinase expression was determined in day 0 and day 10 HSC. Increased UCHL1 expression was confirmed in human HSC and in an alcoholic liver disease (ALD) patient liver. The importance of UCHL1 in hepatic fibrosis was investigated in CCl4 and bile duct ligation injured mice using a pharmacological inhibitor (LDN 57444). The effects of UCHL1 inhibition on HSC proliferation were confirmed by Western blot and 3H thymidine incorporation. RESULTS: Here we report that pharmacological inhibition of UCHL1 blocks progression of established fibrosis in CCl4 injured mice. UCHL1 siRNA knockdown, LDN 57444 treatment, or HSC isolated from UCHL1(-/-) mice show attenuated proliferation in response to the mitogen, platelet-derived growth factor. Additionally, we observed changes in the phosphorylation of the cell cycle regulator retinoblastoma protein (Rb) in the absence of UCHL1 highlighting a potential mechanism for the reduced proliferative response. CONCLUSIONS: UCHL1 expression is highly upregulated upon HSC activation and is involved in the regulation of HSC proliferation. This study highlights therapeutic opportunities for pharmacological targeting of UCHL1 in chronic liver disease.

Endoscopic ultrasound in patients with normal liver blood tests and unexplained dilatation of common bile duct and or pancreatic duct.

OBJECTIVE: To determine the yield of endoscopic ultrasound (EUS) in the investigation of patients with normal liver function tests (LFTs) and unexplained dilatation of common bile duct (CBD) and/or pancreatic duct (PD), following CT and/or magnetic resonance cholangiopancreatography. MATERIALS AND METHODS: Consecutive patients undergoing linear EUS between January 2007 and August 2011 for the indication of dilated CBD and/or PD, normal LFT, and nondiagnostic cross-sectional imaging formed the study group. The study was performed as a retrospective analysis of prospectively collected data. RESULTS: During the study period, 83 patients (CBD and PD dilatation n = 38, PD dilatation n = 5, CBD dilatation n = 40) met the inclusion criteria and underwent EUS. Five (13.1%) of the CBD and PD groups had a new finding, which in one (2.6%) case was causal. In this group, men were significantly more likely to have a new finding (p = 0.012). Eight (20%) of the CBD group had a new finding, which in seven (17.5%) cases was causal. In the CBD group, cholecystectomy was significantly (p = 0.005) more common in those without a finding. Three (60%) of the PD group had a finding on EUS, all of which were causal, including a case of pancreatic malignancy. CONCLUSION: There is a significant yield from EUS in individuals with isolated PD dilatation and isolated CBD dilatation. Previous cholecystectomy is significantly associated with a negative EUS in the group with isolated CBD dilatation. The yield in those with CBD and PD dilatation was low and a finding was more likely in males.

UCHL1-dependent control of hypoxia-inducible factor transcriptional activity during liver fibrosis.

Liver fibrosis is the excessive accumulation of extracellular matrix proteins that occurs in most types of chronic liver disease. At the cellular level, liver fibrosis is associated with the activation of hepatic stellate cells (HSCs) which transdifferentiate into a myofibroblast-like phenotype that is contractile, proliferative and profibrogenic. HSC transdifferentiation induces genome-wide changes in gene expression that enable the cell to adopt its profibrogenic functions. We have previously identified that the deubiquitinase ubiquitin C-terminal hydrolase 1 (UCHL1) is highly induced following HSC activation; however, the cellular targets of its deubiquitinating activity are poorly defined. Here, we describe a role for UCHL1 in regulating the levels and activity of hypoxia-inducible factor 1 (HIF1), an oxygen-sensitive transcription factor, during HSC activation and liver fibrosis. HIF1 is elevated during HSC activation and promotes the expression of profibrotic mediator HIF target genes. Increased HIF1α expression correlated with induction of UCHL1 mRNA and protein with HSC activation. Genetic deletion or chemical inhibition of UCHL1 impaired HIF activity through reduction of HIF1α levels. Furthermore, our mechanistic studies have shown that UCHL1 elevates HIF activity through specific cleavage of degradative ubiquitin chains, elevates levels of pro-fibrotic gene expression and increases proliferation rates. As we also show that UCHL1 inhibition blunts fibrogenesis in a pre-clinical 3D human liver slice model of fibrosis, these results demonstrate how small molecule inhibitors of DUBs can exert therapeutic effects through modulation of HIF transcription factors in liver disease. Furthermore, inhibition of HIF activity using UCHL1 inhibitors may represent a therapeutic opportunity with other HIF-related pathologies.