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.

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.

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.

Prognosis of sporadic resected small (≤2 cm) nonfunctional pancreatic neuroendocrine tumors - a multi-institutional study.

BACKGROUND: Malignant potential of small (≤20 mm) nonfunctional pancreatic neuroendocrine tumors (sNF-PNET) is difficult to predict and management remain controversial. The aim of this study was to assess the prognosis of sporadic nonmetastatic sNF-PNETs. METHODS: Patients were identified from databases of 16 centers. Outcomes and risk factors for recurrence were identified by uni- and multivariate analyses. RESULTS: sNF-PNET was resected in 210 patients, and 66% (n = 138) were asymptomatic. Median age was 60 years, median tumor size was 15 mm, parenchyma-sparing surgery was performed in 42%. Postoperative mortality was 0.5% (n = 1), severe morbidity rate was 14.3% (n = 30), and 14 of 132 patients (10.6%) with harvested lymph nodes had metastatic lymph nodes. Tumor size, presence of biliary or pancreatic duct dilatation, and WHO grade 2-3 were independently associated with recurrence. Patients with tumors sized ≤10 mm were disease free at last follow-up. The 1-, 3- and 5-year disease-free survival rates for patients with tumors sized 11-20 mm on preoperative imaging were 95.1%, 91.0%, and 87.3%, respectively. CONCLUSIONS: In sNF-PNETs, the presence of biliary or pancreatic duct dilatation or WHO grade 2-3 advocate for surgical treatment. In the remaining patients, a wait-and-see policy might be considered.

Chronic pancreatitis: Do serum biomarkers provide an association with an inflammageing phenotype?

BACKGROUND: Chronic pancreatitis is an inflammatory disorder of the pancreas that is associated with accelerated mortality for patients suffering from this disease. The association between chronic inflammation and accelerated biological ageing has been well described and is often referred to as "inflammageing". In this review we seek to determine how systemic inflammation in chronic pancreatitis may contribute to an accelerated ageing phenotype. METHODS: A systematic literature search with a predefined search protocol was performed on Medline, Embase and Cochrane libraries according to the PRISMA guidelines. RESULTS: The initial search identified 499 studies. After title, abstract and full text screen of the search results, 20 were included for further evaluation. In the 20 remaining articles 41 inflammatory mediators were identified - mainly involved in chronic inflammation, fibrosis and particularly cardinal features of inflammageing such as sarcopenia and osteoporosis. CONCLUSION: Chronic pancreatitis is associated with elevated levels of inflammatory mediators many of which are associated with an accelerated ageing phenotype and may explain some of the clinical sequelae of this disease.

An experimental study to identify the potential role of pharmacogenomics in determining the occurrence of oxaliplatin-induced liver injury.

BACKGROUND: Oxaliplatin-based chemotherapy has been linked to the development of sinusoidal obstruction syndrome (SOS), which is detrimental to outcome after liver resection for colorectal liver metastases (CLM). The aim of this study was to determine how the expression of genes involved in the transport and metabolism of FOLFOX chemotherapy impacts on tissue injury in a murine model of CLM. METHODS: Experimental CLM was established in C57/B16 mice and treated with FOLFOX chemotherapy. After 3 weeks, the animals were killed and RNA extracted from liver, spleen and tumour tissue. DNA damage was assessed by immunohistochemistry for γH2AX. Gene expression was determined by reverse transcriptase polymerase chain reaction. RESULTS: FOLFOX treatment was associated with an increase in the number of γH2AX-positive cells in both the spleen (P < 0.01) and tumour tissue (P < 0.01), but not the liver. Tissue resistance to injury following FOLFOX was associated with high expression of the copper transporter ATP7B. Differences in the expression of genes related to 5-fluorouracil metabolism or DNA repair did not correlate with the severity of tissue injury. CONCLUSIONS: High levels of expression of ATP7B are associated with resistance to tissue injury following FOLFOX chemotherapy. Polymorphisms in the ATP7B gene may explain varying susceptibility to SOS among patients following oxaliplatin-based chemotherapy.

N-acetylcysteine administration does not improve patient outcome after liver resection.

BACKGROUND: Post-operative hepatic dysfunction is a major cause of concern when undertaking a liver resection. The generation of reactive oxygen species (ROS) as a result of hepatic ischaemia/reperfusion (I/R) injury can result in hepatocellular injury. Experimental evidence suggests that N-acetylcysteine may ameliorate ROS-mediated liver injury. METHODS: A cohort of 44 patients who had undergone a liver resection and receiving peri-operative N-acetylcysteine (NAC) were compared with a further cohort of 44 patients who did not. Liver function tests were compared on post-operative days 1, 3 and 5. Peri-operative outcome data were retrieved from a prospectively maintained database within our unit. RESULTS: Administration of NAC was associated with a prolonged prothrombin time on the third post-operative day (18.4 versus 16.4 s; P = 0.002). The incidence of grades B and C liver failure was lower in the NAC group although this difference did not reach statistical significance (6.9% versus 14%; P = 0.287). The overall complication rate was similar between groups (32% versus 25%; P = ns). There were two peri-operative deaths in the NAC group and one in the control group (P = NS). CONCLUSION: In spite of promising experimental evidence, this study was not able to demonstrate any advantage in the routine administration of peri-operative NAC in patients undergoing a liver resection.

Chemotherapy-associated liver injury in patients with colorectal liver metastases: a systematic review and meta-analysis.

BACKGROUND: Chemotherapy-associated liver injury is a major cause for concern when treating patients with colorectal liver metastases. The aim of this review was to determine the pathological effect of specific chemotherapy regimens on the hepatic parenchyma as well as on surgical morbidity, mortality and overall survival. METHODS: A systematic review of the published literature and a meta-analysis were performed. For each of the variables under consideration, the effects of different chemotherapy regimens were determined by calculation of relative risks by a random-effects model. RESULTS: Hepatic parenchymal injury is regimen specific, with oxaliplatin-based regimens being associated with grade 2 or greater sinusoidal injury (number needed to harm 8; 95 % confidence interval [CI] 6.4-13.6), whereas irinotecan-based regimens associated with steatohepatitis (number needed to harm 12; 95 % CI 7.8-26). The use of bevacizumab alongside FOLFOX reduces the risk of grade 2 or greater sinusoidal injury (relative risk 0.34; 95 % CI 0.15-0.75). CONCLUSIONS: Chemotherapy before resection of colorectal liver metastases is associated with an increased risk of regimen-specific liver injury. This liver injury may have implications for the functional reserve of the liver for patients undergoing major hepatectomy for colorectal liver metastases.

Laparoscopic liver resection: is there a learning curve?

BACKGROUND: Laparoscopic liver resection (LLR) is becoming an accepted treatment option for resecting both benign and malignant tumours. However, it is critical that the laparoscopic approach does not compromise the technical quality of the liver resection. The aim of this paper was to review the learning curve of LLR in a specialist HPB unit. METHODS: A prospective database was searched to identify patients undergoing LLR over a 4-year period. To assess the effect of the learning curve on outcome, the series was evaluated during two eras--early versus late. RESULTS: Fifty-one (27 males, median age 68 years) patients were identified with 37 having LLR. The most common indication was for colorectal liver metastases, and the most common procedure was a non-anatomical metastectomy. Changes in management decisions (n = 14) occurred more frequently during the first era (9 vs. 5; p > 0.05). More patients underwent right hepatectomy in the late group (3 vs. 1; p < 0.05). There did not appear to be any difference in duration of surgery for laparoscopic left lateral resection between the eras (200 vs. 240 min; p > 0.05) which probably reflected trainees performing more operations during the late era. Left hepatectomy was most commonly performed in the early era compared to more right hepatectomies during the late era. CONCLUSION: LLR is associated with a learning curve, but once this has been overcome it can be safely utilised in the management of malignant liver lesions even for major resections, surgical training and simultaneous resections.

Non-invasive synchronous monitoring of neutrophil migration using whole body near-infrared fluorescence-based imaging.

Advances in fluorescence imaging coupled with the generation of near infrared probes have significantly improved the capabilities of non-invasive, real-time imaging in whole animals. In this study we were able to overcome a limitation of in vivo fluorescence imaging and have established a dual cell tracking method where two different cell types can be monitored according to the spectral signature of the cell labelling fluorophore. Using a mouse model of acute liver injury, we have characterised the in vivo migration patterns of wild type and transgenic neutrophils with impaired chemotaxis. Here, we were able to demonstrate that IVIS provides a sensitive multiplexing technology to differentiate two different cell populations based on the spectral signature of the cell labelling fluorophores. This spectral unmixing methodology has the potential to uncover multidimensional cellular interactions involved in many diseases such as fibrosis and cancer. In vivo spectral un-mixing provides a useful tool for monitoring multiple biological process in real-time in the same animal.

Role of nuclear factor kappaB in liver health and disease.

NF-kappaB (nuclear factor kappaB) is a heterodimeric transcription factor that is constitutively expressed in all cell types and has a central role as a transcriptional regulator in response to cellular stress. In the present review, we discuss the role of NF-kappaB signalling in the maintenance of liver homoeostasis as well as in the pathogenesis of a wide variety of conditions affecting the liver, including viral hepatitis, steatohepatitis, cirrhosis and hepatocellular carcinoma. Much of the current knowledge of NF-kappaB signalling in the liver relates to the canonical pathway, the IKK [IkappaB (inhibitor of kappaB) kinase] complex and the RelA subunit. We explore the weaknesses of the experimental approaches to date and suggest that further work is needed to investigate in detail the discreet functions of each of the Rel subunits in liver physiology and disease.

RNA sequencing reveals changes in the microRNAome of transdifferentiating hepatic stellate cells that are conserved between human and rat.

MicroRNAs are small (~ 22nt long) noncoding RNAs (ncRNAs) that regulate gene expression at the post-transcriptional level. Over 2000 microRNAs have been described in humans and many are implicated in human pathologies including tissue fibrosis. Hepatic stellate cells (HSC) are the major cellular contributors to excess extracellular matrix deposition in the diseased liver and as such are important in the progression of liver fibrosis. We employed next generation sequencing to map alterations in the expression of microRNAs occurring across a detailed time course of culture-induced transdifferentiation of primary human HSC, this a key event in fibrogenesis. Furthermore, we compared profiling of human HSC microRNAs with that of rat HSC so as to identify those molecules that are conserved with respect to modulation of expression. Our analysis reveals that a total of 229 human microRNAs display altered expression as a consequence of HSC transdifferentiation and of these 104 were modulated early during the initiation phase. Typically modulated microRNAs were targeting kinases, transcription factors, chromatin factors, cell cycle regulators and growth factors. 162 microRNAs changed in expression during transdifferentiation of rat HSC, however only 17 underwent changes that were conserved in human HSC. Our study therefore identifies widespread changes in the expression of HSC microRNAs in fibrogenesis, but suggests a need for caution when translating data obtained from rodent HSC to events occurring in human cells.

Therapeutic Strategies Toward Lactate Dehydrogenase Within the Tumor Microenvironment of Pancreatic Cancer.

OBJECTIVES: Pancreatic stellate cells (PSCs) play a key metabolic role within the tumor microenvironment (stroma) of pancreatic ductal adenocarcinoma (PDAC), being glycolytic and associated with protumorigenic acidification from excess lactate. This study investigates the clinical significance of glycolytic enzyme lactate dehydrogenase (LDH) and determines efficacy of the novel pan-LDH inhibitor Galloflavin. METHODS: An in vitro Transwell system was adopted for coculture of PSCs and 3 PDAC cell lines (MIA PaCa-2, PANC-1, and BxPC-3). Cells were treated with Galloflavin, and outcomes were analyzed regarding proliferation, apoptosis, lactate production, and glycolytic enzyme protein expression. Immunohistochemical staining for lactate dehydrogenase B (LDHB) was performed on 59 resected PDAC tumors annotated for clinical outcome. RESULTS: Galloflavin reduced PDAC proliferation in monoculture (P < 0.01); however, in co-culture with PSCs, an antiproliferative effect was only evident in PANC-1 (P = 0.001). An apoptotic effect was observed in MIA PaCa-2 and BxPC-3 in coculture (P < 0.05). A reduction in media lactate was observed in coculture (P < 0.01) with PSCs. Immunohistochemistry revealed stromal and tumoral LDHB expression had no impact on survival. CONCLUSIONS: Galloflavin has the potential to neutralize the acidic PDAC microenvironment and thereby reduce tumor invasiveness and metastasis. Patients with lower LDHB expression are more likely to be beneficial responders.

c-Rel orchestrates energy-dependent epithelial and macrophage reprogramming in fibrosis.

Fibrosis is a common pathological feature of chronic disease. Deletion of the NF-κB subunit c-Rel limits fibrosis in multiple organs, although the mechanistic nature of this protection is unresolved. Using cell-specific gene-targeting manipulations in mice undergoing liver damage, we elucidate a critical role for c-Rel in controlling metabolic changes required for inflammatory and fibrogenic activities of hepatocytes and macrophages and identify Pfkfb3 as the key downstream metabolic mediator of this response. Independent deletions of Rel in hepatocytes or macrophages suppressed liver fibrosis induced by carbon tetrachloride, while combined deletion had an additive anti-fibrogenic effect. In transforming growth factor-ß1-induced hepatocytes, c-Rel regulates expression of a pro-fibrogenic secretome comprising inflammatory molecules and connective tissue growth factor, the latter promoting collagen secretion from HMs. Macrophages lacking c-Rel fail to polarize to M1 or M2 states, explaining reduced fibrosis in RelΔLysM mice. Pharmacological inhibition of c-Rel attenuated multi-organ fibrosis in both murine and human fibrosis. In conclusion, activation of c-Rel/Pfkfb3 in damaged tissue instigates a paracrine signalling network among epithelial, myeloid and mesenchymal cells to stimulate fibrogenesis. Targeting the c-Rel-Pfkfb3 axis has potential for therapeutic applications in fibrotic disease.

Systemic inflammation contributes to impairment of quality of life in chronic pancreatitis.

Chronic pancreatitis (CP) is a fibrotic disorder of the pancreas leading to clinical sequelae like pain and an excess of comorbidity including cardiovascular disease and cancers. The aim of this study was to determine the relationship between systemic inflammation and quality of life in patients with CP. Patients were prospectively recruited and underwent a quality of life assessment (EORTC QLQ-C30 and PAN 28). The serum inflammatory profile was assessed using an MSD 30-plex array. The relationship between clinical variables, inflammatory cytokines and quality of life was determined by a GLM-MANOVA and the individual impact of significant variables evaluated by a second ANOVA. In total, 211 patients with a median age of 53 years were recruited across 5 European centres. Gender, age, nicotine and alcohol abuse were clinical variables associated with altered quality of life. Systemic inflammation with high levels of pro-inflammatory cytokines (Eotaxin, IL-1ß, IL-7, IL-8, IL-12/IL-23p40, IL-12p70, IL-13, IL-16, IP-10, MCP-1, MCP-4, MDC, MIP-1a, TARC, TNFß) was associated with diminished quality of life in general and specific domains including pain, physical and cognitive functioning. As conclusion, CP is associated with a systemic inflammatory response that has a negative impact on quality of life and accelerates aging.

Risk and protective factors for the occurrence of sporadic pancreatic endocrine neoplasms.

Pancreatic neuroendocrine neoplasms (PNENs) represent 10% of all pancreatic tumors by prevalence. Their incidence has reportedly increased over recent decades in parallel with that of pancreatic adenocarcinoma. PNENs are relatively rare, and of the few institutions that have published potential risk factors, findings have been heterogeneous. Our objective was to investigate the association between potential risk and protective factors for the occurrence of sporadic PNENs across a European population from several institutions. A multinational European case-control study was conducted to examine the association of selected environmental, family and medical exposure factors using a standardized questionnaire in face-to-face interviews. A ratio of 1:3 cases to controls were sex and age matched at each study site. Adjusted univariate and multivariate logistic regression analysis were performed for statistically significant factors. The following results were obtained: In 201 cases and 603 controls, non-recent onset diabetes (OR 2.09, CI 1.27-3.46) was associated with an increased occurrence of PNENs. The prevalence of non-recent onset diabetes was higher both in cases with metastatic disease (TNM stage III-IV) or advanced grade (G3) at the time of diagnosis. The use of metformin in combination with insulin was also associated with a more aggressive phenotype. Drinking coffee was more frequent in cases with localized disease at diagnosis. Our study concluded that non-recent onset diabetes was associated with an increased occurrence of PNENs and the combination of metformin and insulin was consistent with a more aggressive PNEN phenotype. In contrast to previous studies, smoking, alcohol and first-degree family history of cancer were not associated with PNEN occurrence.

The role of exosomes in the pathogenesis of pancreatic ductal adenocarcinoma.

Exosomes are small membrane bound vesicles secreted by cancer cells that have a cytosol rich in proteins and nucleic acids which are capable of modulating the phenotype of neighbouring cells which take them up. In this review we explore the mechanisms through which exosomes are able to impact on the pathogenesis of pancreatic ductal cancer through the modulation of tumour formation and development and exploitation of the tumour microenvironment to modulate both the adaptive and innate immune response. In addition we highlight the potential utility of exosomes not only as biomarkers of disease but also as tools to be used in the therapeutic armamentarium against this disease.

Differential DNA methylation of genes involved in fibrosis progression in non-alcoholic fatty liver disease and alcoholic liver disease.

BACKGROUND: Chronic liver injury can lead to the development of liver fibrosis and cirrhosis but only in a minority of patients. Currently, it is not clear which factors determine progression to fibrosis. We investigated whether DNA\methylation profile as determined by pyrosequencing can distinguish patients with mild from those with advanced/severe fibrosis in non-alcoholic liver disease (NAFLD) and alcoholic liver disease (ALD). To this end, paraffin-embedded liver biopsies were collected from patients with biopsy-proven NAFLD or ALD, as well as paraffin-embedded normal liver resections, genomic DNA isolated, bisulfite converted and pyrosequencing assays used to quantify DNA methylation at specific CpGs within PPARα, PPARα, TGFß1, Collagen 1A1 and PDGFα genes. Furthermore, we assessed the impact of age, gender and anatomical location within the liver on patterns of DNA methylation in the same panel of genes. RESULTS: DNA methylation at specific CpGs within genes known to affect fibrogenesis distinguishes between patients with mild from those with severe fibrosis in both NAFLD and ALD, although same CpGs are not equally represented in both etiologies. In normal liver, age, gender or anatomical location had no significant impact on DNA methylation patterns in the liver. CONCLUSIONS: DNA methylation status at specific CpGs may be useful as part of a wider set of patient data for predicting progression to liver fibrosis.