The gut-liver axis refers to the bidirectional relationship between the gut and its microbiota, and the liver, resulting from the integration of signals generated by dietary, genetic and ...environmental factors. This reciprocal interaction is established by the portal vein which enables transport of gut-derived products directly to the liver, and the liver feedback route of bile and antibody secretion to the intestine. The intestinal mucosal and vascular barrier is the functional and anatomical structure that serves as a playground for the interactions between the gut and the liver, limiting the systemic dissemination of microbes and toxins while allowing nutrients to access the circulation and to reach the liver. The control of microbial communities is critical to maintaining homeostasis of the gut-liver axis, and as part of this bidirectional communication the liver shapes intestinal microbial communities. Alcohol disrupts the gut-liver axis at multiple interconnected levels, including the gut microbiome, mucus barrier, epithelial barrier and at the level of antimicrobial peptide production, which increases microbial exposure and the proinflammatory environment of the liver. Growing evidence indicates the pathogenetic role of microbe-derived metabolites, such as trimethylamine, secondary bile acids, short-chain fatty acids and ethanol, in the pathogenesis of non-alcoholic fatty liver disease. Cirrhosis by itself is associated with profound alterations in gut microbiota and damage at the different levels of defence of the intestinal barrier, including the epithelial, vascular and immune barriers. The relevance of the severe disturbance of the intestinal barrier in cirrhosis has been linked to translocation of live bacteria, bacterial infections and disease progression. The identification of the elements of the gut-liver axis primarily damaged in each chronic liver disease offers possibilities for intervention. Beyond antibiotics, upcoming therapies centred on the gut include new generations of probiotics, bacterial metabolites (postbiotics), faecal microbial transplantation, and carbon nanoparticles. FXR-agonists target both the gut and the liver and are currently being tested in different liver diseases. Finally, synthetic biotic medicines, phages that target specific bacteria or therapies that create physical barriers between the gut and the liver offer new therapeutic approaches.
In advanced chronic liver disease (CLD), the translocation of intestinal bacteria and the resultant increase of proinflammatory cytokines in the splanchnic and systemic circulation may contribute to ...the progression of fibrosis. We therefore speculated that fibrosis and portal hypertension (PHT) would be attenuated in a mouse model of limited intestinal colonization with altered Schaedler flora (ASF) compared to a more complex colonization with specific pathogen‐free (SPF) flora. We induced liver fibrosis in ASF and SPF mice by common bile duct ligation (BDL) or by carbon tetrachloride (CCl4) treatment. We then measured portal pressure (PP), portosystemic shunts (PSSs), and harvested tissues for further analyses. There were no differences in PP between sham‐treated ASF or SPF mice. After BDL or CCl4 treatment, PP, PSSs, and hepatic collagen deposition increased in both groups. However, the increase in PP and the degree of fibrosis was significantly higher in ASF than SPF mice. Expression of fibrotic markers α‐smooth muscle actin, desmin, and platelet‐derived growth factor receptor β were significantly higher in ASF than SPF mice. This was associated with higher activation of hepatic immune cells (macrophages, neutrophils) and decreased expression of the intestinal epithelial tight junction proteins (claudin‐1, occludin‐1). In 2 models of advanced CLD, SPF mice presented significantly attenuated liver injury, fibrosis, and PHT compared to ASF mice. In contrast to our hypothesis, these findings suggest that a complex intestinal microbiota may play a “hepatoprotective” role.—Moghadamrad, S., Hassan, M., McCoy, K. D., Kirundi, J., Kellmann, P., De Gottardi, A. Attenuated fibrosis in specific pathogen‐free microbiota in experimental cholestasis‐ and toxin‐induced liver injury. FASEB J. 33, 12464–12476 (2019). www.fasebj.org
Liver stiffness is increasingly used in the non-invasive evaluation of chronic liver diseases. Liver stiffness correlates with hepatic venous pressure gradient (HVPG) in patients with cirrhosis and ...holds prognostic value in this population. Hence, accuracy in its measurement is needed. Several factors independent of fibrosis influence liver stiffness, but there is insufficient information on whether meal ingestion modifies liver stiffness in cirrhosis. We investigated the changes in liver stiffness occurring after the ingestion of a liquid standard test meal in this population.
In 19 patients with cirrhosis and esophageal varices (9 alcoholic, 9 HCV-related, 1 NASH; Child score 6.9±1.8), liver stiffness (transient elastography), portal blood flow (PBF) and hepatic artery blood flow (HABF) (Doppler-Ultrasound) were measured before and 30 minutes after receiving a standard mixed liquid meal. In 10 the HVPG changes were also measured.
Post-prandial hyperemia was accompanied by a marked increase in liver stiffness (+27±33%; p<0.0001). Changes in liver stiffness did not correlate with PBF changes, but directly correlated with HABF changes (r = 0.658; p = 0.002). After the meal, those patients showing a decrease in HABF (n = 13) had a less marked increase of liver stiffness as compared to patients in whom HABF increased (n = 6; +12±21% vs. +62±29%,p<0.0001). As expected, post-prandial hyperemia was associated with an increase in HVPG (n = 10; +26±13%, p = 0.003), but changes in liver stiffness did not correlate with HVPG changes.
Liver stiffness increases markedly after a liquid test meal in patients with cirrhosis, suggesting that its measurement should be performed in standardized fasting conditions. The hepatic artery buffer response appears an important factor modulating postprandial changes of liver stiffness. The post-prandial increase in HVPG cannot be predicted by changes in liver stiffness.
Liver regeneration is of crucial importance for patients undergoing living liver transplantations or extended liver resections and can be associated with elevated portal venous pressure, impaired ...hepatic regeneration, and postoperative morbidity. The aim of this study was to assess whether reduction of portal venous pressure by terlipressin improves postoperative liver regeneration in normal and steatotic livers after partial hepatectomy in a rodent model.
Portal venous pressure was assessed after minor (30%), standard (60%), or extended (80%) partial hepatectomy (PH) in mice with and without liver steatosis. Liver regeneration was assessed by BrdU incorporation and Ki-67 immunostaining.
Portal venous pressure was significantly elevated post-PH in mice with normal and steatotic livers compared to sham-operated mice. Reduction of elevated portal pressure after 80% PH by terlipressin was associated with an increase of hepatocellular proliferation. In steatotic livers, animals treated with terlipressin had an increase in liver regeneration after 30% PH and increased survival after 60% PH. Mechanistically, terlipressin alleviated IL-6 mRNA expression following PH and down-regulated p21 and GADD45 mRNA suggesting a reduction of cell cycle inhibition and cellular stress.
Reduction of elevated portal pressure post-PH by the use of terlipressin improves liver regeneration after PH in lean and steatotic mouse livers.
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•For intestinal bacteria to enter the systemic circulation they must cross the mucus, epithelial and gut-vascular barrier.•Cirrhosis, but not portal hypertension per se, grossly ...impairs the endothelial and muco-epithelial barriers.•This promotes pathological bacterial translocation via the portal-venous circulation.•Both barriers appear to be FXR-modulated, as FXR-agonists reduce portal-venous bacterial translocation.
Pathological bacterial translocation (PBT) in cirrhosis is the hallmark of spontaneous bacterial infections, increasing mortality several-fold. Increased intestinal permeability is known to contribute to PBT in cirrhosis, although the role of the mucus layer has not been addressed in detail. A clear route of translocation for luminal intestinal bacteria is yet to be defined, but we hypothesize that the recently described gut-vascular barrier (GVB) is impaired in experimental portal hypertension, leading to increased accessibility of the vascular compartment for translocating bacteria.
Cirrhosis was induced in mouse models using bile-duct ligation (BDL) and CCl4. Pre-hepatic portal-hypertension was induced by partial portal vein ligation (PPVL). Intestinal permeability was compared in these mice after GFP-Escherichia coli or different sized FITC-dextrans were injected into the intestine.
Healthy and pre-hepatic portal-hypertensive (PPVL) mice lack translocation of FITC-dextran and GFP-E. coli from the small intestine to the liver, whereas BDL and CCl4-induced cirrhotic mice demonstrate pathological translocation, which is not altered by prior thoracic-duct ligation. The mucus layer is reduced in thickness, with loss of goblet cells and Muc2-staining and expression in cirrhotic but not PPVL mice. These changes are associated with bacterial overgrowth in the inner mucus layer and pathological translocation of GFP-E. coli through the ileal epithelium. GVB is profoundly altered in BDL and CCl4-mice with Ileal extravasation of large-sized 150 kDa-FITC-dextran, but only slightly altered in PPVL mice. This pathological endothelial permeability and accessibility in cirrhotic mice is associated with augmented expression of PV1 in intestinal vessels. OCA but not fexaramine stabilizes the GVB, whereas both FXR-agonists ameliorate gut to liver translocation of GFP-E. coli.
Cirrhosis, but not portal hypertension per se, grossly impairs the endothelial and muco-epithelial barriers, promoting PBT to the portal-venous circulation. Both barriers appear to be FXR-modulated, with FXR-agonists reducing PBT via the portal-venous route.
For intestinal bacteria to enter the systemic circulation, they must cross the mucus and epithelial layer, as well as the gut-vascular barrier. Cirrhosis disrupts all 3 of these barriers, giving bacteria access to the portal-venous circulation and thus, the gut-liver axis. Diminished luminal bile acid availability, cirrhosis and the associated reduction in farnesoid x receptor (FXR) signaling seem, at least partly, to mediate these changes, as FXR-agonists reduce bacterial translocation via the portal-venous route to the liver in cirrhosis.
Background
Treatment of refractory ascites in liver cirrhosis is challenging. Transjugular intrahepatic portosystemic shunt and alfapump® have been proposed for the management, but few data comparing ...both exist.
Aims
The aim of this study was to evaluate the characteristics and outcomes of patients treated with transjugular intrahepatic portosystemic shunt and alfapump® for refractory ascites at our centre.
Methods
All consecutive patients were retrospectively reviewed for baseline characteristics, efficacy of treatment, complications and survival.
Results
In total, 19 patients with transjugular intrahepatic portosystemic shunt and 40 patients with alfapump® were included. Patients with transjugular intrahepatic portosystemic shunt had better liver function and less hepatic encephalopathy at baseline. Fifty-eight per cent of patients developed hepatic encephalopathy in the first six months after transjugular intrahepatic portosystemic shunt. In patients with alfapump®, renal function decreased and 58% developed prerenal impairment and 43% hepatorenal syndrome in the first six months. Alfapump® patients with new catheters required less reinterventions (26% versus 57% with old catheters, p = 0.049). Transplant-free survival at 1 year was 25% in alfapump® and 65% in transjugular intrahepatic portosystemic shunt. Hepatic encephalopathy predicted transplant-free survival in patients with alfapump® (hazard ratio 2.00, 95% confidence interval 0.99–4.02, p = 0.05). In a sensitivity analysis comparing patients with similar liver function, the rate of hepatorenal syndrome and prerenal impairment was higher in patients with alfapump® and these patients were hospitalised more frequently, whereas the rate of hepatic encephalopathy was similar in both treatment groups.
Conclusions
Both transjugular intrahepatic portosystemic shunt and alfapump® were effective treatments for refractory ascites in cirrhosis. Patients treated with transjugular intrahepatic portosystemic shunt had a better one-year transplant-free survival but had less negative prognostic factors at baseline. Selecting patients without hepatic encephalopathy prior to implantation of an alfapump® might improve transplant-free survival.
Cirrhotic patients with refractory ascites (RA) can be treated with repeated large volume paracentesis (LVP), with the insertion of a transjugular intrahepatic portosystemic shunt (TIPS) or with ...liver transplantation. However, side effects and complications of these therapeutic options, as well as organ shortage, warrant the development of novel treatments.
The automated low-flow ascites pump (alfapump®) is a subcutaneously-implanted novel battery-driven device that pumps ascitic fluid from the peritoneal cavity into the urinary bladder. Ascites can therefore be aspirated in a time- and volume-controlled mode and evacuated by urination.
Here we review the currently available data about patient selection, efficacy and safety of the alfapump and provide recommendations for the management of patients treated with this new method.
Budd-Chiari syndrome and non-cirrhotic non-tumoral portal vein thrombosis are 2 rare disorders, with several similarities that are categorized under the term splanchnic vein thrombosis. Both ...disorders are frequently associated with an underlying prothrombotic disorder. They can cause severe portal hypertension and usually affect young patients, negatively influencing life expectancy when the diagnosis and treatment are not performed at an early stage. Yet, they have specific features that require individual consideration. The current review will focus on the available knowledge on pathophysiology, diagnosis and management of both entities.
Acute‐on‐chronic liver failure (ACLF) in cirrhosis is an increasingly recognized syndrome characterized by acute decompensation, organ failure(s) and high short‐term mortality. Recent findings ...suggest that an overexuberant systemic inflammation plays a primary role in ACLF progression. In this study, we examined whether genetic factors shape systemic immune responses in patients with decompensated cirrhosis. Six single‐nucleotide polymorphisms (SNPs) in inflammation‐related genes (interleukin IL‐1 beta IL‐1β, rs1143623; IL‐1 receptor antagonist IL‐1ra, rs4251961; IL‐10, rs1800871; suppressor of cytokine signaling‐3, rs4969170; nucleotide‐binding oligomerization domain‐containing protein 2, rs3135500; and chemerin chemokine‐like receptor 1, rs1878022) were genotyped in 279 patients with cirrhosis with (n = 178) and without (n = 101) ACLF from the CANONIC study of the CLIF consortium. Among these SNPs, we identified two polymorphisms belonging to the IL‐1 gene cluster (IL‐1β and IL‐1ra) in strong association with ACLF. Both SNPs were protective against ACLF; IL‐1β (odds ratio OR, 0.34, 95% confidence interval CI, 0.13‐0.89; P < 0.05) and IL‐1ra (OR, 0.58; 95% CI, 0.35‐0.95; P < 0.05) under the recessive and overdominant inheritance models, respectively. These protective SNPs translated into reduced circulating levels of IL‐1β, IL‐1α, IL‐6, granulocyte‐colony stimulating factor, granulocyte‐macrophage colony‐stimulating factor, and C‐reactive protein at enrollment as well as after 7‐14 days of admission. These findings were confirmed in vitro in leukocytes incubated with plasma from patients with decompensated cirrhosis carrying the protective SNP genotypes. Notably, a higher frequency of the protective genotypes was observed in patients without (80%) than in those with (20%) ACLF. Consistently, patients carrying the combined protective genotypes showed a lower 28‐day mortality rate. Conclusion: These data identify two common functional polymorphisms in the IL‐1 gene cluster, which are associated with the inflammatory process related to development of ACLF. (Hepatology 2017;65:202‐216).
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