The genetic regulation of the gastric transcriptome is associated with metabolic and obesity-related traits and diseases.

Tissue-specific gene expression and gene regulation lead to a better understanding of tissue-specific physiology and pathophysiology. We analyzed the transcriptome and genetic regulatory profiles of two distinct gastric sites, corpus and antrum, to identify tissue-specific gene expression and its regulation. Gastric corpus and antrum mucosa biopsies were collected during routine gastroscopies from up to 431 healthy individuals. We obtained genotype and transcriptome data and performed transcriptome profiling and expression quantitative trait locus (eQTL) studies. We further used data from genome-wide association studies (GWAS) of various diseases and traits to partition their heritability and to perform transcriptome-wide association studies (TWAS). The transcriptome data from corpus and antral mucosa highlights the heterogeneity of gene expression in the stomach. We identified enriched pathways revealing distinct and common physiological processes in gastric corpus and antrum. Furthermore, we found an enrichment of the single nucleotide polymorphism (SNP)-based heritability of metabolic, obesity-related, and cardiovascular traits and diseases by considering corpus- and antrum-specifically expressed genes. Particularly, we could prioritize gastric-specific candidate genes for multiple metabolic traits, like NQO1 which is involved in glucose metabolism, MUC1 which contributes to purine and protein metabolism or RAB27B being a regulator of weight and body composition. Our findings show that gastric corpus and antrum vary in their transcriptome and genetic regulatory profiles indicating physiological differences which are mostly related to digestion and epithelial protection. Moreover, our findings demonstrate that the genetic regulation of the gastric transcriptome is linked to biological mechanisms associated with metabolic, obesity-related, and cardiovascular traits and diseases. NEW & NOTEWORTHY We analyzed the transcriptomes and genetic regulatory profiles of gastric corpus and for the first time also of antrum mucosa in 431 healthy individuals. Through tissue-specific gene expression and eQTL analyses, we uncovered unique and common physiological processes across both primary gastric sites. Notably, our findings reveal that stomach-specific eQTLs are enriched in loci associated with metabolic traits and diseases, highlighting the pivotal role of gene expression regulation in gastric physiology and potential pathophysiology.

Improving primary prophylaxis of variceal bleeding by adapting therapy to the clinical stage of cirrhosis. A competing-risk meta-analysis of individual participant data.

BACKGROUND & AIMS: Non-selective ß-blockers (NSBBs) and endoscopic variceal-ligation (EVL) have similar efficacy preventing first variceal bleeding. Compensated and decompensated cirrhosis are markedly different stages, which may impact treatment outcomes. We aimed to assess the efficacy of NSBBs vs EVL on survival in patients with high-risk varices without previous bleeding, stratifying risk according to compensated/decompensated stage of cirrhosis. METHODS: By systematic review, we identified RCTs comparing NSBBs vs EVL, in monotherapy or combined, for primary bleeding prevention. We performed a competing-risk, time-to-event meta-analysis, using individual patient data (IPD) obtained from principal investigators of RCTs. Analyses were stratified according to previous decompensation of cirrhosis. RESULTS: Of 25 RCTs eligible, 14 failed to provide IPD and 11 were included, comprising 1400 patients (656 compensated, 744 decompensated), treated with NSBBs (N = 625), EVL (N = 546) or NSBB+EVL (N = 229). Baseline characteristics were similar between groups. Overall, mortality risk was similar with EVL vs. NSBBs (subdistribution hazard-ratio (sHR) = 1.05, 95% CI = 0.75-1.49) and with EVL + NSBBs vs either monotherapy, with low heterogeneity (I2 = 28.7%). In compensated patients, mortality risk was higher with EVL vs NSBBs (sHR = 1.76, 95% CI = 1.11-2.77) and not significantly lower with NSBBs+EVL vs NSBBs, without heterogeneity (I2 = 0%). In decompensated patients, mortality risk was similar with EVL vs. NSBBs and with NSBBs+EVL vs. either monotherapy. CONCLUSIONS: In patients with compensated cirrhosis and high-risk varices on primary prophylaxis, NSBBs significantly improved survival vs EVL, with no additional benefit noted adding EVL to NSBBs. In decompensated patients, survival was similar with both therapies. The study suggests that NSBBs are preferable when advising preventive therapy in compensated patients.

Standard versus Endocuff versus cap-assisted colonoscopy for adenoma detection: A randomised controlled clinical trial.

BACKGROUND AND AIMS: Adenoma detection rate (ADR) in colon cancer screening is most important for cancer prophylaxis. This work is the first three-armed randomised controlled clinical trial aimed at comparing a head-to-head setting standard colonoscopy (SC) with Endocuff-assisted colonoscopy (EC) and cap-assisted colonoscopy (CAC) for improvement of ADR. METHODS: Patients from Poland and Germany with independent indication for colonoscopy were randomised into three arms of this trial: EC, CAC and SC. Exclusion criteria were age <18 years, active Crohn's disease or ulcerative colitis, known stenosis and post-colonic resection status. RESULTS: A total of 585 patients (195 SC, 189 EC and 186 CAC) were enrolled in this study. Indications were not different between the groups (colorectal cancer screening 51%, diagnostic colonoscopy in 31% and post-polypectomy follow-up in 18%; p = 0.94). Withdrawal time was a mean of 7 min in all groups (p = 0.658), and bowel preparation did not differ between the groups. The time to reach the caecum was significantly reduced when using the cap (a mean of 6 min for CAC vs. 7 min for SC; p = 0.0001). There was no significant difference in the primary outcome of the ADR between the groups (EC 32%, CAC 30%, SC 30%; p = 0.815). EC proved to be superior (EC vs. SC) in the sigmoid colon and transverse colon for polyp detection. CONCLUSION: The use of EC increased the total number of polyps seen during colonoscopy. In contrast to recent studies, no significant improvement of the ADR was detected.

Prevention of Rebleeding From Esophageal Varices in Patients With Cirrhosis Receiving Small-Diameter Stents Versus Hemodynamically Controlled Medical Therapy.

BACKGROUND & AIMS: Patients with cirrhosis and variceal hemorrhage have a high risk of rebleeding. We performed a prospective randomized trial to compare the prevention of rebleeding in patients given a small-diameter covered stent vs those given hepatic venous pressure gradient (HVPG)-based medical therapy prophylaxis. METHODS: We performed an open-label study of patients with cirrhosis (92% Child class A or B, 70% alcoholic) treated at 10 medical centers in Germany. Patients were assigned randomly more than 5 days after variceal hemorrhage to groups given a small covered transjugular intrahepatic portosystemic stent-shunt (TIPS) (8 mm; n = 90), or medical reduction of portal pressure (propranolol and isosorbide-5-mononitrate; n = 95). HVPG was determined at the time patients were assigned to groups (baseline) and 2 weeks later. In the medical group, patients with an adequate reduction in HVPG (responders) remained on the drugs whereas nonresponders underwent only variceal band ligation. The study was closed 10 months after the last patient was assigned to a group. The primary end point was variceal rebleeding. Survival, safety (adverse events), and quality of life (based on the Short Form-36 health survey) were secondary outcome measures. RESULTS: A significantly smaller proportion of patients in the TIPS group had rebleeding within 2 years (7%) than in the medical group (26%) (P = .002). A slightly higher proportion of patients in the TIPS group experienced adverse events, including encephalopathy (18% vs 8% for medical treatment; P = .05). Rebleeding occurred in 6 of 23 patients (26%) receiving medical treatment before hemodynamic control was possible. Per-protocol analysis showed that rebleeding occurred in a smaller proportion of the 32 responders (18%) than in nonresponders who received variceal band ligation (31%) (P = .06). Fifteen patients from the medical group (16%) underwent TIPS placement during follow-up evaluation, mainly for refractory ascites. Survival time and quality of life did not differ between both randomized groups. CONCLUSIONS: Placement of a small-diameter, covered TIPS was straightforward and prevented variceal rebleeding in patients with Child A or B cirrhosis more effectively than drugs, which often required step-by-step therapy. However, TIPS did not increase survival time or quality of life and produced slightly more adverse events. Clinical Trial no: ISRCTN 16334693.

Novel endocuff-assisted colonoscopy significantly increases the polyp detection rate: a randomized controlled trial.

GOALS AND BACKGROUND: Screening colonoscopy for colorectal cancer has proven to reduce mortality rates. Recently the Endocuff (EC), an attachment to the distal tip of the colonoscope, was introduced. The aim of our study was to compare EC-assisted colonoscopies with standard colonoscopies for the detection of colonic polyps. STUDY: This study is a randomized prospective 2-center trial. The study was conducted at 2 tertiary care centers. PARTICIPANTS: A total of 498 patients [249 males; median age 67 y; interquartile range (IQR), 56-75 y] for colon adenoma screening purposes were included. All patients underwent standard colonoscopy with or without the use of EC. Overall polyp detection rate, the number of colonic polyps, and the polyp distribution in the colon were measured. Difference in recognition of polyps with or without the use of EC was assessed. Statistical analysis was applied. RESULTS: In the EC group, the number of polyps detected per patient was 63% higher [2.00 (IQR, 1.00-4.00) vs. 1.00 (IQR, 1.00-2.25), P<0.0001]. The polyp detection rate in patients increased by 14% with the use of EC (56% vs. 42%, P=0.001). For polyp detection, superiority by use of EC could be observed in the sigmoid (P=0.001) and cecum (P=0.002) for polyps <1 cm in diameter. In the EC group, the number of adenomas detected per patient significantly increased by 86% (P=0.002). No major complications occurred in both groups. CONCLUSIONS: The use of the EC is feasible and safe with significantly higher polyp detection rates, especially for those located in the sigmoid region. The cuff system has the potential to improve the accuracy of screening colonoscopies.

Higher adenoma detection rates with endocuff-assisted colonoscopy - a randomized controlled multicenter trial.

OBJECTIVES: The Endocuff is a device mounted on the tip of the colonoscope to help flatten the colonic folds during withdrawal. This study aimed to compare the adenoma detection rates between Endocuff-assisted (EC) colonoscopy and standard colonoscopy (SC). METHODS: This randomized prospective multicenter trial was conducted at four academic endoscopy units in Germany. PARTICIPANTS: 500 patients (235 males, median age 64[IQR 54-73]) for colon adenoma detection purposes were included in the study. All patients were either allocated to EC or SC. The primary outcome measure was the determination of the adenoma detection rates (ADR). RESULTS: The ADR significantly increased with the use of the Endocuff compared to standard colonoscopy (35.4%[95% confidence interval{CI} 29-41%] vs. 20.7%[95%CI 15-26%], p<0.0001). Significantly more sessile polyps were detected by EC. Overall procedure time and withdrawal time did not differ. Caecal and ileum intubation rates were similar. No major adverse events occurred in both groups. In multivariate analysis, age (odds ratio [OR] 1.03; 95%[CI] 1.01-1.05), male sex (OR 1.74; 95%CI 1.10-2.73), withdrawal time (OR 1.16; 95%CI 1.05-1.30), procedure time (OR 1.07; 95%CI 1.04-1.10), colon cleanliness (OR 0.60; 95%CI 0.39-0.94) and use of Endocuff (OR 2.09; 95%CI 1.34-3.27) were independent predictors of adenoma detection rates. CONCLUSIONS: EC increases the adenoma detection rate by 14.7%(95%CI 6.9-22.5%). EC is safe, effective, easy to handle and might reduce colorectal interval carcinomas. TRIAL REGISTRATION: ClinicalTrials.gov NCT02034929.

Fulminant sepsis after liver biopsy: A long forgotten complication?

We report on a 74-year-old patient with recurrent cholangitis and a large juxtapapillary duodenal diverticulum. Despite drainage of the common bile duct by an endoscopically placed stent, the elevated liver enzymes normalized only partially. To rule out other possible causes of liver injury, a percutaneous liver biopsy was done. After the liver biopsy the patient developed fulminant septic shock and died within 24 h. We discuss the possible causes of the septic shock following percutaneous liver biopsy in our patient and give a concise overview of the literature.

Intrahepatic IL-8 producing Foxp3⁺CD4⁺ regulatory T cells and fibrogenesis in chronic hepatitis C.

BACKGROUND & AIMS: Regulatory CD4(+) T cells (Tregs) are considered to affect outcomes of HCV infection, because they increase in number during chronic hepatitis C and can suppress T-cell functions. METHODS: Using microarray analysis, in situ immunofluorescence, ELISA, and flowcytometry, we characterised functional differentiation and localisation of adaptive Tregs in patients with chronic hepatitis C. RESULTS: We found substantial upregulation of IL-8 in Foxp3(+)CD4(+) Tregs from chronic hepatitis C. Activated GARP-positive IL-8(+) Tregs were particularly enriched in livers of patients with chronic hepatitis C in close proximity to areas of fibrosis and their numbers were correlated with the stage of fibrosis. Moreover, Tregs induced upregulation of profibrogenic markers TIMP1, MMP2, TGF-beta1, alpha-SMA, collagen, and CCL2 in primary human hepatic stellate cells (HSC). HSC activation, but not Treg suppressor function, was blocked by adding a neutralizing IL-8 antibody. CONCLUSIONS: Our studies identified Foxp3(+)CD4(+) Tregs as an additional intrahepatic source of IL-8 in chronic hepatitis C acting on HSC. Thus, Foxp3(+)CD4(+) Tregs in chronic hepatitis C have acquired differentiation as regulators of fibrogenesis in addition to suppressing local immune responses.

Nodular regenerative hyperplasia and portal hypertension in a patient with coeliac disease.

Nodular regenerative hyperplasia (NRH) of the liver is often associated with rheumatologic or lymphoproliferative disorders and a cause of portal hypertension in some patients. We report the case of a 71-year-old patient with celiac disease and unexplained portal hypertension. Biopsy of the liver revealed NRH as the underlying cause. The patient did not suffer from an autoimmune, rheumatologic or lymphoproliferative disease. A thrombophilic disorder that might cause NRH was ruled out. Celiac disease is often associated with mild elevation of liver enzymes and steatosis of the liver, but the association with NRH was described in only a few patients. We discuss the possible relationship of celiac disease and NRH.

Degree of hepatic dysfunction and improvement of renal function predict survival in patients with HRS type I: a retrospective analysis.

BACKGROUND: Hepatorenal syndrome (HRS) is a frequent complication of end-stage liver cirrhosis. HRS type I has a very poor prognosis. From which of the more or less established therapies, such as use of vasoconstrictors together with albumin or placement of a Transjugular Intrahepatic Portosystemic Shunt patients might profit remains elusive. Therefore, it is important to define parameters that predict an improved outcome in respect to kidney function and survival. METHODS: The clinical charts of 91 patients with cirrhosis and HRS type I were studied. The parameters associated with response to therapy, defined as a decrease in serum creatinine of more than 1.5 mg/dl on day 14 after diagnosis of HRS, and those associated with survival were assessed by multivariate analysis. RESULTS: The median survival was 2.7 (1.5-3.8) months. Three independent predictive factors for survival were identified: Child-Pugh score (P = 0.05), Model of End-Stage Liver Disease (MELD) score less than 20 (P = 0.01), and response to therapy (P = 0.02). The Child-Pugh score (P = 0.00) and MELD score less than 20 (P = 0.02) were the parameters independently associated with the response to therapy, which occurred in 26% of the patients. CONCLUSION: Our data of this large monocentric series with HRS type I confirm the poor prognosis in these patients, especially in those with high Child-Pugh and MELD scores, and in those in whom kidney function does not improve within 2 weeks.

Coexisting gastric varices should not preclude prophylactic ligation of large esophageal varices in cirrhosis.

BACKGROUND/AIMS: Coexisting gastric varices at baseline or the risk of their formation during treatment could alter the approach for primary bleeding prophylaxis in patients with large esophageal varices. METHODS: Data analysis of 152 patients with cirrhosis and large esophageal varices included in the German multicenter trial on primary prevention of variceal bleeding. RESULTS: 20 patients (13.6%) had coexisting gastric varices at baseline (GOV+). 10 of those each received either band ligation or propranolol, respectively. During follow-up (34.4 +/- 18.9 months) new gastric varices occurred in 2/75 (2.7%, ligation) and 4/77 (5.2%, propranolol) patients, respectively. One patient with newly developed gastric varices bled (propranolol group). GOV+ patients had a better baseline liver function and overall survival. Bleeding incidence did not differ significantly between GOV+ and GOV- patients (3-year actuarial risk: 20.0 +/- 10.6% (GOV+), 38.1 +/- 4.4% (GOV-), p = 0.195). Among GOV+ patients, bleeding occurred in 3/10 patients of the propranolol group and in 0/10 in the ligation group (p = 0.038). CONCLUSION: Prophylactic band ligation of large esophageal varices is safe and effective also in patients with coexisting gastric varices. Band ligation did not increase the risk of secondary gastric varices compared to propranolol.

Does therapy of oesophageal varices influences the progression of varices?

BACKGROUND: Aim of this study was to determine the progression time of oesophageal varices in patients with cirrhosis and to study whether therapy of varices has an impact on the progression time. Parameters associated with the progression of oesophageal varices were analyzed as well. METHODS: One hundred and eighty-one cirrhotic patients (Child A/B/C: 105/69/15; Child score 7.6+/-2.0, initial variceal grade 1.7+/-0.9) undergoing repeated endoscopy for follow-up and/or treatment of oesophageal varices were retrospectively analyzed. A multivariate logistic regression analysis was applied to identify independent determinants of progression of oesophageal varices. RESULTS: Of the 189 patients, 26 patients were on beta-blocker therapy only, 52 patients underwent ligation therapy only, and 37 patients received a combination of ligation and beta-blocker therapy of varices. The mean time of progression of oesophageal varices by one grade was 384+/-364 days. This interval did not vary significantly between patients who underwent no treatment or were on a beta-blocker and/or ligation therapy. The serum bilirubin (hazard ratio 1.030; 95% confidence interval, 1.004, 1.055; P<0.03) was the only parameter independently associated with the progression of varices. Initial eradication of varices was achieved after 2.2+/-1.5 ligation sessions. Rings of 6.1+/-2.5 were used in the first banding session and 11.5+/-8.9 rings were needed to achieve eradication of varices. CONCLUSION: Therapy of oesophageal varices does not influence the progression time of oesophageal varices in patients with cirrhosis of the liver.

Regulatory mechanisms underlying agmatine homeostasis in humans.

Regulation of agmatine homeostasis has so far only been poorly defined. In the present study, three mechanisms regulating human agmatine homeostasis were investigated. 1) Enzymatic regulation: expression of arginine decarboxylase, diamine oxidase, and ornithine decarboxylase in human colon neoplastic tissue was, at the mRNA level, about 75% and 50% lower and 150% higher, respectively, than in the adjacent normal tissue; expression of agmatinase was unchanged. 2) Bacteria-derived agmatine: ten representative bacteria strains of the human intestinal microbiota considerably differed in agmatine production and its efflux into their surrounding fluid, suggesting that the composition of the intestinal microbiota influences the agmatine availability in the gut lumen for absorption. 3) Regulation of blood plasma agmatine concentration by the human liver: at low concentrations in portal venous blood plasma, agmatine either slightly increased or further decreased in blood plasma through liver passage. Above a threshold of 14 ng/ml agmatine in the portal venous blood plasma, substantial hepatic agmatine removal from blood occurred. Taken together, a perturbation of agmatine homeostasis has been proven to be involved in the regulation of malignant cell proliferation. The amount of agmatine available for absorption, which is an important physiological source of agmatine in the human organism, should differ considerably depending on the composition of the bacterial flora in the chyme since the various species of intestinal bacteria largely differ in their ability to form agmatine. Finally, evidence has been presented that the liver plays a crucial physiological role in the maintenance of agmatine homeostasis in the human organism.

Irbesartan plus low-dose propranolol versus low-dose propranolol alone in cirrhosis: a placebo-controlled, double-blind study.

OBJECTIVES: Angiotensin II receptor antagonists have been shown to moderately lower portal pressure in some patients with cirrhosis but may have adverse effects on kidney function. This study aimed at comparing the effects of a combined treatment using irbesartan plus propranolol with propranolol monotherapy on portal pressure and kidney function in patients with cirrhosis. METHODS: Thirty-two patients were included (Child A/B/C: 13/18/1, etiology: 16 alcohol, 13 viral, 3 other; bilirubin 1.4 +/- 1.1 mg/dL, creatinine 0.86 +/- 0.20 mg/dL, baseline hepatic venous pressure gradient 18.7 +/- 5.3 mmHg). All patients received 20 mg propranolol b.i.d. Additionally, they randomly received either placebo (N = 15) or irbesartan (step-up dosage titration up to 300 mg/d, N = 17). Patients were followed at weekly intervals, re-evaluation of hepatic venous pressure gradient (HVPG) was performed after 8 wk. RESULTS: One patient in the propranolol/irbesartan group was excluded due to variceal bleeding. No other adverse events occurred. Portal pressure declined in both groups (propranolol/irbesartan group 19.6 +/- 1.5 mmHg to 16.6 +/- 1.2 mmHg, P= 0.037, propranolol/placebo group 17.8 +/- 1.1 mmHg to 15.1 +/- 1.2 mmHg, P= 0.019). Sodium excretion significantly increased in the propranolol/irbesartan group (from 122 +/- 20 mmol/d to 230 +/- 23 mmol/d, P= 0.045), but not in the propranolol/placebo group. CONCLUSIONS: Combination treatment of propranolol plus irbesartan is well tolerated in cirrhotic patients when titrating the angiotensin II antagonist in a step-up manner, and it increases sodium excretion in patients with compensated or moderately decompensated cirrhosis. Addition of irbesartan has no effect on portal pressure.

Prevention of paracentesis-induced circulatory dysfunction: midodrine vs albumin. A randomized pilot study.

BACKGROUND/AIMS: Large-volume paracentesis in patients with cirrhosis and ascites induces arterial vasodilatation and decreases effective arterial blood volume, termed paracentesis-induced circulatory dysfunction (PICD), which can be prevented by costly intravenous albumin. Vasoconstrictors, e.g. terlipressin, may also prevent PICD. The aim was to compare the less expensive vasoconstrictor midodrine, an alpha-adrenoceptor agonist, with albumin in preventing PICD. METHODS: Twenty-four patients with cirrhosis and ascites were randomly assigned to be treated with either midodrine (n=11) (12.5 mg three times per day; over 2 days) or albumin (n=13) (8 g/L of removed ascites) after large-volume paracentesis. Effective arterial blood volume was assessed indirectly by measuring plasma renin and aldosterone concentration on days 0 and 6 after paracentesis; renal function and haemodynamic changes were also measured. PICD was defined as an increase in plasma renin concentration on day 6 by more than 50% of the baseline value. RESULTS: PICD developed in six patients of the midodrine group (60%) and in only four patients (31%) of the albumin group. Six days after paracentesis, the aldosterone concentration increased significantly in the midodrine group, but not in the albumin group. CONCLUSIONS: This pilot study suggests that midodrine is not as effective as albumin in preventing circulatory dysfunction after large-volume paracentesis in patients with cirrhosis and ascites.

Prognostic role of the initial portal pressure gradient reduction after TIPS in patients with cirrhosis.

BACKGROUND: The aim of this study was to determine the prognostic relevance of the portal pressure gradient (PPG) before and after transjugular intrahepatic portosystemic stent shunt (TIPS) insertion in patients with liver cirrhosis and recurrent oesophageal variceal bleeding. METHODS: 118 cirrhotic patients (Child A/B/C, 41/56/21; Child score, 7.7+/-2.0; baseline PPG, 21.8+/-4.7 mmHg) underwent TIPS for the prevention of variceal rebleeding. A multivariate logistic regression analysis was applied to identify the independent determinants of rebleeding and survival. The estimated rebleeding rate and the estimated survival were compared by log-rank testing. RESULTS: TIPS insertion reduced the PPG by 53.2+/-17.7%. During follow-up 21 patients suffered significant rebleeding (17.8%); bleeding-related mortality was 3.4% (four patients). The median survival [95% confidence intervals (CI)] was 48.2 (39.8; 60.8) months. The multivariate Cox model identified creatinine as the only independent predictor of survival, and the initial decrease of the PPG after TIPS as the only independent predictor of rebleeding. PPG before TIPS (21.8+/-4.7 mmHg) and the gradient at the time of rebleeding (22.0+/-2.9 mmHg) did not differ significantly. Patients with an initial decrease of the PPG after TIPS <30% were at the highest risk for rebleeding. Patients with an initial decrease of the PPG >60% rarely suffered from rebleeding. CONCLUSIONS: The initial decrease in the PPG after TIPS is a predictor for the risk of rebleeding but not for survival after TIPS. For that reason, in patients undergoing TIPS placement for the prevention of recurrent bleeding from oesophageal varices, an initial reduction of the PPG of 30-50% should be attempted.

Atorvastatin lowers portal pressure in cirrhotic rats by inhibition of RhoA/Rho-kinase and activation of endothelial nitric oxide synthase.

UNLABELLED: In cirrhosis, increased RhoA/Rho-kinase signaling and decreased nitric oxide (NO) availability contribute to increased intrahepatic resistance and portal hypertension. Hepatic stellate cells (HSCs) regulate intrahepatic resistance. 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) inhibit synthesis of isoprenoids, which are necessary for membrane translocation and activation of small GTPases like RhoA and Ras. Activated RhoA leads to Rho-kinase activation and NO synthase inhibition. We therefore investigated the effects of atorvastatin in cirrhotic rats and isolated HSCs. Rats with secondary biliary cirrhosis (bile duct ligation, BDL) were treated with atorvastatin (15 mg/kg per day for 7 days) or remained untreated. Hemodynamic parameters were determined in vivo (colored microspheres). Intrahepatic resistance was investigated in in situ perfused livers. Expression and phosphorylation of proteins were analyzed by RT-PCR and immunoblots. Three-dimensional stress-relaxed collagen lattice contractions of HSCs were performed after incubation with atorvastatin. Atorvastatin reduced portal pressure without affecting mean arterial pressure in vivo. This was associated with a reduction in intrahepatic resistance and reduced responsiveness of in situ-perfused cirrhotic livers to methoxamine. Furthermore, atorvastatin reduced the contraction of activated HSCs in a 3-dimensional stress-relaxed collagen lattice. In cirrhotic livers, atorvastatin significantly decreased Rho-kinase activity (moesin phosphorylation) without affecting expression of RhoA, Rho-kinase and Ras. In activated HSCs, atorvastatin inhibited the membrane association of RhoA and Ras. Furthermore, in BDL rats, atorvastatin significantly increased hepatic endothelial nitric oxide synthase (eNOS) mRNA and protein levels, phospho-eNOS, nitrite/nitrate, and the activity of the NO effector protein kinase G (PKG). CONCLUSION: In cirrhotic rats, atorvastatin inhibits hepatic RhoA/Rho-kinase signaling and activates the NO/PKG-pathway. This lowers intrahepatic resistance, resulting in decreased portal pressure. Statins might represent a therapeutic option for portal hypertension in cirrhosis.

Vascular dysfunction in human and rat cirrhosis: role of receptor-desensitizing and calcium-sensitizing proteins.

UNLABELLED: In cirrhosis, vascular hypocontractility leads to vasodilation and contributes to portal hypertension. Impaired activation of contractile pathways contributes to vascular hypocontractility. Angiotensin II type 1 receptors (AT1-Rs) are coupled to the contraction-mediating RhoA/Rho-kinase pathway and may be desensitized by phosphorylation through G-protein-coupled receptor kinases (GRKs) and binding of beta-arrestin-2. In the present study, we analyzed vascular hypocontractility to angiotensin II in cirrhosis. Human hepatic arteries were obtained during liver transplantation. In rats, cirrhosis was induced by bile duct ligation (BDL). Contractility of rat aortic rings was measured myographically. Protein expression and phosphorylation were analyzed by Western blot analysis. Immunoprecipitation was performed with protein A-coupled Sepharose beads. Myosin light chain (MLC) phosphatase activity was assessed as dephosphorylation of MLCs. Aortas from BDL rats were hyporeactive to angiotensin II and extracellular Ca2+. Expression of AT1-R and Galphaq/11,12,13 remained unchanged in hypocontractile rat and human vessels, whereas GRK-2 and beta-arrestin-2 were up-regulated. The binding of beta-arrestin-2 to the AT1-R was increased in hypocontractile rat and human vessels. Inhibition of angiotensin II-induced aortic contraction by the Rho-kinase inhibitor Y-27632 was pronounced in BDL rats. Basal phosphorylation of the ROK-2 substrate moesin was reduced in vessels from rats and patients with cirrhosis. Analysis of the expression and phosphorylation of Ca(2+)-sensitizing proteins (MYPT1 and CPI-17) in vessels from rats and patients with cirrhosis suggested decreased Ca2+ sensitivity. Angiotensin II-stimulated moesin phosphorylation was decreased in aortas from BDL rats. MLC phosphatase activity was elevated in aortas from BDL rats. CONCLUSION: Vascular hypocontractility to angiotensin II in cirrhosis does not result from changes in expression of AT1-Rs or G-proteins. Our data suggest that in cirrhosis-induced vasodilation, the AT1-R is desensitized by GRK-2 and beta-arrestin-2 and that changed patterns of phosphorylated Ca(2+) sensitizing proteins decrease Ca(2+) sensitivity.