Background: Animal data suggest a role of the gut-liver axis in progression of alcoholic liver disease (ALD), but human data are scarce especially for early disease stages. Methods: We included patients with alcohol use disorder (AUD) who follow a rehabilitation program and matched healthy controls. We determined intestinal epithelial and vascular permeability (IP) (using urinary excretion of 51 Cr-EDTA, fecal albumin content, and immunohistochemistry in distal duodenal biopsies), epithelial damage (histology, serum iFABP, and intestinal gene expression), and microbial translocation (Gram-and Gram + serum markers by ELISA). Duodenal mucosaassociated microbiota and fecal microbiota were analyzed by 16 S rRNA sequencing. ALD was staged by Fibroscan® (liver stiffness, controlled attenuation parameter) in combination with serum AST, ALT, and CK18-M65. Results: Only a subset of AUD patients had increased 51 Cr-EDTA and fecal albumin together with disrupted tight junctions and vasculature expression of plasmalemma Vesicle-Associated Protein-1. The so-defined increased intestinal permeability was not related to changes of the duodenal microbiota or alterations of the intestinal epithelium but associated with compositional changes of the fecal microbiota. Leaky gut alone did not explain increased microbial translocation in AUD patients. By contrast, duodenal dysbiosis with a dominance shift toward specific potential pathogenic bacteria genera (Streptococcus, Shuttleworthia, Rothia), increased IP and elevated markers of microbial translocation characterized AUD patients with progressive ALD (steato-hepatitis, steatofibrosis). Conclusion: Progressive ALD already at early disease stages is associated with duodenal mucosaassociated dysbiosis and elevated microbial translocation. Surprisingly, such modifications were not linked with increased IP. Rather, increased IP appears related to fecal microbiota dysbiosis.

ObjectivePancreatic cancer can arise from precursor lesions called intraductal papillary mucinous neoplasms (IPMN), which are characterised by cysts containing papillae and mucus-producing cells. The high frequency of KRAS mutations in IPMN and histological analyses suggest that oncogenic KRAS drives IPMN development from pancreatic duct cells. However, induction of Kras mutation in ductal cells is not sufficient to generate IPMN, and formal proof of a ductal origin of IPMN is still missing. Here we explore whether combining oncogenic KrasG12D mutation with an additional gene mutation known to occur in human IPMN can induce IPMN from pancreatic duct cells.DesignWe created and phenotyped mouse models in which mutations in Kras and in the tumour suppressor gene liver kinase B1 (Lkb1/Stk11) are conditionally induced in pancreatic ducts using Cre-mediated gene recombination. We also tested the effect of β-catenin inhibition during formation of the lesions.ResultsActivating KrasG12D mutation and Lkb1 inactivation synergised to induce IPMN, mainly of gastric type and with malignant potential. The mouse lesions shared several features with human IPMN. Time course analysis suggested that IPMN developed from intraductal papillae and glandular neoplasms, which both derived from the epithelium lining large pancreatic ducts. β-catenin was required for the development of glandular neoplasms and subsequent development of the mucinous cells in IPMN. Instead, the lack of β-catenin did not impede formation of intraductal papillae and their progression to papillary lesions in IPMN.ConclusionOur work demonstrates that IPMN can result from synergy between KrasG12D mutation and inactivation of a tumour suppressor gene. The ductal epithelium can give rise to glandular neoplasms and papillary lesions, which probably both contribute to IPMN formation.

Portal hyperperfusion and “dearterialization” of the liver remnant are the main pathogenic mechanisms for Small For Size syndrome (SFSS). Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) induces rapid remnant hypertrophy. We hypothesized a similar increase in portal pressure/flow into the future liver remnant in ALPPS and SFSS‐setting hepatectomies. In a rodent model, ALPPS was compared to SFSS‐setting hepatectomy. We assessed mortality, remnant hypertrophy, hepatocyte proliferation, portal and hepatic artery flow, hypoxia‐induced response, and liver sinusoidal morphology. SFSS‐hepatectomy rats were subjected to local (hepatic artery ligation) or systemic (Dimethyloxalylglycine) hypoxia. ALLPS prevented mortality in SFSS‐setting hepatectomies. Portal hyperperfusion per liver mass was similar in ALLPS and SFSS. Compared to SFSS, efficient arterial perfusion of the remnant was significantly lower in ALPPS causing pronounced hypoxia confirmed by pimonidazole immunostaining, activation of hypoxia sensors and upregulation of neo‐angiogenic genes. Liver sinusoids, larger in ALPPS, collapsed in SFSS. Induction of hypoxia in SFSS reduced mortality. Hypoxia had no impact on hepatocyte proliferation but contributed to the integrity of sinusoidal morphology. ALPPS hemodynamically differ from SFSS by a much lower arterial flow in ALPPS's FLR. We show that the ensuing hypoxic response is essential for the function of the regenerating liver by preserving sinusoidal morphology.

KRAS is a powerful oncogene responsible for the development of many cancers. Despite the great progress in understanding its function during the last decade, the study of KRAS expression, subcellular localization, and post-translational modifications remains technically challenging. Accordingly, many facets of KRAS biology are still unknown. Antibodies could be an effective and easy-to-use tool for in vitro and in vivo research on KRAS. Here, we generated a novel rabbit polyclonal antibody that allows immunolabeling of cells and tissues overexpressing KRAS. Cell transfection experiments with expression vectors for the members of the RAS family revealed a preferential specificity of this antibody for KRAS. In addition, KRAS was sensitively detected in a mouse tissue electroporated with an expression vector. Interestingly, our antibody was able to detect endogenous forms of unprenylated (immature) and prenylated (mature) KRAS in mouse organs. We found that KRAS prenylation was increased ex vivo and in vivo in a model of KRASG12D-driven tumorigenesis, which was concomitant with an induction of expression of essential KRAS prenylation enzymes. Therefore, our tool helped us to put the light on new regulations of KRAS activation during cancer initiation. The use of this tool by the RAS community could contribute to discovering novel aspects of KRAS biology.

After extended hepatectomy, hepatocyte proliferation proceeds sinusoidal endothelial cell (SEC) remodeling causing a transient perturbation of the lobular architecture with proliferating hepatocytes forming avascular, hypoxic, clusters. Hypoxia is, thus, considered at the origin of liver dysfunction in SFSS-hepatectomy. Recently, we showed that activation of hypoxia sensors in an upfront SFSShepatectomy surged an early angiogenic switch and preserved the sinusoidal architecture with a favorable impact on survival. Aim: to decipher the role hypoxia-induced angiogenesis in SFSS-setting hepatectomy. Methods: we developed a mouse model of SFSS-hepatectomy (PHx-80%) and used PHx-70% as controls. SFSShepatectomy mice were submitted to normoxia (inspired oxygen fraction-FiO 2 : 21%), local hypoxia (hepatic artery ligation (PHx-HAL)), and systemic hypoxia by placing the animals in hypoxic chambers (FiO 2 : 11%, PHx-HC). We assessed mortality, hepatocyte and liver SEC proliferation. Results: Compared to PHx-70%, PHx-80% showed high mortality rates (68% on postoperative day (POD) 7 (p=0,002)). Hepatocyte proliferation on POD 3 was higher in PHx-80% (p=0,03), while SEC proliferation did not differ, suggesting an amplified disorganization of the regenerating lobule in SFSS-hepatectomy. Compared to normoxic PHx-80%, PHx-HAL tended to have a favorable impact on survival (75% on POD3), while animals subjected to SFSS-hepatectomy and placed into hypoxic chambers showed improved survival (p=0,0007). Hepatocyte proliferation was similar between the hypoxic and normoxic SFSS-liver remnants. However, local and systemic hypoxia significantly triggered early angiogenesis. Conclusions: The current data suggest that hypoxia rescues survival from SFSS. By balancing angiogenesis with hepatocyte proliferation, hypoxia restores the lobular liver architecture allowing an efficient regeneration after major hepatectomy.