Felix Braun

Genetic variation in the PNPLA3 gene is associated with alcoholic liver injury in caucasians.

A recent genome‐wide study revealed an association between variation in the PNPLA3 gene and liver fat content. In addition, the PNPLA3 single‐nucleotide polymorphism rs738409 (M148I) was reported to be associated with advanced alcoholic liver disease in alcohol‐dependent individuals of Mestizo descent. We therefore evaluated the impact of rs738409 on the manifestation of alcoholic liver disease in two independent German cohorts. Genotype and allele frequencies of rs738409 (M148I) were determined in 1,043 alcoholic patients with or without alcoholic liver injury and in 376 at‐risk drinkers from a population‐based cohort. Relative to alcoholic patients without liver damage (n = 439), rs738409 genotype GG was strongly overrepresented in patients with alcoholic liver cirrhosis (n = 210; OR 2.79; Pgenotype = 1.2 × 10−5; Pallelic = 1.6 × 10−6) and in alcoholic patients without cirrhosis but with elevated alanine aminotransferase levels (n = 219; OR 2.33; Pgenotype = 0.0085; Pallelic = 0.0042). The latter, biochemically defined association was confirmed in an independent population‐based cohort of at‐risk drinkers with a median alcohol intake of 300 g/week (OR 4.75; Pgenotype = 0.040; Pallelic = 0.022), and for aspartate aminotransferase (AST) levels. Frequencies of allele PNPLA3 rs738409(G) in individuals with steatosis and normal alanine aminotransferase (ALT) and AST levels were lower than in alcoholics without steatosis and normal ALT/AST (Pcombined = 0.03). The population attributable risk of cirrhosis in alcoholic carriers of allele PNPLA3 rs738409(G) was estimated at 26.6%. Conclusion: Genotype PNPLA3 rs738409(GG) is associated with alcoholic liver cirrhosis and elevated aminotransferase levels in alcoholic Caucasians. (HEPATOLOGY 2011)

Three ulcerative colitis susceptibility loci are associated with primary sclerosing cholangitis and indicate a role for IL2, REL and CARD9

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by inflammation and fibrosis of the bile ducts. Both environmental and genetic factors contribute to its pathogenesis. To further clarify its genetic background, we investigated susceptibility loci recently identified for ulcerative colitis (UC) in a large cohort of 1,186 PSC patients and 1,748 controls. Single nucleotide polymorphisms (SNPs) tagging 13 UC susceptibility loci were initially genotyped in 854 PSC patients and 1,491 controls from Benelux (331 cases, 735 controls), Germany (265 cases, 368 controls), and Scandinavia (258 cases, 388 controls). Subsequently, a joint analysis was performed with an independent second Scandinavian cohort (332 cases, 257 controls). SNPs at chromosomes 2p16 (P‐value 4.12 × 10−4), 4q27 (P‐value 4.10 × 10−5), and 9q34 (P‐value 8.41 × 10−4) were associated with PSC in the joint analysis after correcting for multiple testing. In PSC patients without inflammatory bowel disease (IBD), SNPs at 4q27 and 9q34 were nominally associated (P < 0.05). We applied additional in silico analyses to identify likely candidate genes at PSC susceptibility loci. To identify nonrandom, evidence‐based links we used GRAIL (Gene Relationships Across Implicated Loci) analysis showing interconnectivity between genes in six out of in total nine PSC‐associated regions. Expression quantitative trait analysis from 1,469 Dutch and UK individuals demonstrated that five out of nine SNPs had an effect on cis‐gene expression. These analyses prioritized IL2, CARD9, and REL as novel candidates. Conclusion: We have identified three UC susceptibility loci to be associated with PSC, harboring the putative candidate genes REL, IL2, and CARD9. These results add to the scarce knowledge on the genetic background of PSC and imply an important role for both innate and adaptive immunological factors. (HEPATOLOGY 2011;)

Genome-Wide Association Analysis in Primary Sclerosing Cholangitis and Ulcerative Colitis Identifies Risk Loci at GPR35 and TCF4

Approximately 60%‐80% of patients with primary sclerosing cholangitis (PSC) have concurrent ulcerative colitis (UC). Previous genome‐wide association studies (GWAS) in PSC have detected a number of susceptibility loci that also show associations in UC and other immune‐mediated diseases. We aimed to systematically compare genetic associations in PSC with genotype data in UC patients with the aim of detecting new susceptibility loci for PSC. We performed combined analyses of GWAS for PSC and UC comprising 392 PSC cases, 987 UC cases, and 2,977 controls and followed up top association signals in an additional 1,012 PSC cases, 4,444 UC cases, and 11,659 controls. We discovered novel genome‐wide significant associations with PSC at 2q37 [rs3749171 at G‐protein‐coupled receptor 35 (GPR35); P = 3.0 × 10−9 in the overall study population, combined odds ratio [OR] and 95% confidence interval [CI] of 1.39 (1.24‐1.55)] and at 18q21 [rs1452787 at transcription factor 4 (TCF4); P = 2.61 × 10−8, OR (95% CI) = 0.75 (0.68‐0.83)]. In addition, several suggestive PSC associations were detected. The GPR35 rs3749171 is a missense single nucleotide polymorphism resulting in a shift from threonine to methionine. Structural modeling showed that rs3749171 is located in the third transmembrane helix of GPR35 and could possibly alter efficiency of signaling through the GPR35 receptor. Conclusion: By refining the analysis of a PSC GWAS by parallel assessments in a UC GWAS, we were able to detect two novel risk loci at genome‐wide significance levels. GPR35 shows associations in both UC and PSC, whereas TCF4 represents a PSC risk locus not associated with UC. Both loci may represent previously unexplored aspects of PSC pathogenesis. (HEPATOLOGY 2013;58:1074–1083)

Patient Age, Sex, and Inflammatory Bowel Disease Phenotype Associate With Course of Primary Sclerosing Cholangitis

BACKGROUND & AIMSnPrimary sclerosing cholangitis (PSC) is an orphan hepatobiliary disorder associated with inflammatory bowel disease (IBD). We aimed to estimate the risk of disease progression based on distinct clinical phenotypes in a large international cohort of patients with PSC.nnnMETHODSnWe performed a retrospective outcome analysis of patients diagnosed with PSC from 1980 through 2010 at 37 centers in Europe, North America, and Australia. For each patient, we collected data on sex, clinician-reported age at and date of PSC and IBD diagnoses, phenotypes of IBD and PSC, and date and indication of IBD-related surgeries. The primary and secondary endpoints were liver transplantation or death (LTD) and hepatopancreatobiliary malignancy, respectively. Cox proportional hazards models were applied to determine the effects of individual covariates on rates of clinical events, with time-to-event analysis ascertained through Kaplan-Meier estimates.nnnRESULTSnOf the 7121 patients in the cohort, 2616 met the primary endpoint (median time to event of 14.5 years) and 721 developed hepatopancreatobiliary malignancy. The most common malignancy was cholangiocarcinoma (nxa0= 594);xa0patients of advanced age at diagnosis had an increased incidence compared with younger patients (incidence rate: 1.2 per 100 patient-years for patients younger than 20 years old, 6.0 per 100 patient-years for patients 21-30 years old, 9.0 per 100xa0patient-years for patients 31-40 years old, 14.0 per 100 patient-years for patients 41-50 years old, 15.2 per 100 patient-years for patients 51-60 years old, and 21.0 per 100xa0patient-years for patients older than 60 years). Of all patients with PSC studied, 65.5% were men, 89.8% had classical or large-duct disease, and 70.0% developed IBD at some point. Assessing the development of IBD as a time-dependent covariate, Crohns disease and no IBD (both vs ulcerative colitis) were associated with a lower risk of LTD (unadjusted hazard ratio [HR], 0.62; P < .001 and HR, 0.90; Pxa0= .03, respectively) and malignancy (HR, 0.68; Pxa0= .008 and HR, 0.77; Pxa0= .004, respectively). Small-duct PSC was associated with a lower risk of LTD or malignancy compared with classic PSC (HR, 0.30 and HR, 0.15, respectively; both P < .001). Female sex was also associated with a lower risk of LTD or malignancy (HR, 0.88; Pxa0= .002 and HR, 0.68; P < .001, respectively). In multivariable analyses assessing the primary endpoint, small-duct PSC characterized a low-risk phenotype in both sexes (adjusted HR forxa0men, 0.23; P < .001 and adjusted HR for women, 0.48; Pxa0=xa0.003). Conversely, patients with ulcerative colitis had an increased risk of liver disease progression compared with patients with Crohns disease (HR, 1.56; P < .001) or no IBD (HR, 1.15; Pxa0= .002).nnnCONCLUSIONSnIn an analysis of data from individual patients with PSC worldwide, we found significant variation in clinical course associated with age at diagnosis, sex, and ductal and IBD subtypes. The survival estimates provided might be used to estimate risk levels for patients with PSC and select patients for clinical trials.

Pregnancy in primary sclerosing cholangitis

Background There is a paucity of data on fertility or pregnancy in patients with primary sclerosing cholangitis (PSC). Objective To assess fertility in PSC by comparing the number of children in a large cohort of PSC patients to healthy controls and to investigate the outcome of pregnancy, as well as the influence of pregnancy on the disease course. Design Case series. Setting Germany. Participants 229 PSC patients and 569 healthy controls were evaluated for the number of children. 17 patients with PSC and at least one pregnancy, or who received a diagnosis of PSC within 6u2005months after delivery, were included in the more detailed analysis. Main outcome measures Number of children per patient and control; disease activity during pregnancy and after delivery including maternal complications; long-term development of live births, fetal loss rate and the influence of medication on fetal and maternal outcome. Results Fertility did not seem to be reduced in PSC since the number of children did not differ between PSC patients and healthy controls. 25 pregnancies in 17 female PSC patients (median age at conception 31u2005years) were investigated in detail. An increase in liver enzymes was documented during five pregnancies (20%) and eight times (32%) post-partum. There were no serious maternal complications. All 21 live births presented with a normal perinatal and postnatal development over a median observation time of 50 months. Two pregnancies were delivered pre-term and four fetal losses occurred early in pregnancy (<12 wk). Continuation of treatment with ursodeoxycholic acid (15/21) or azathioprine (2/21) had no negative effects on pregnancy outcome. Conclusions Fertility does not seem to be reduced in patients with PSC, who are able to deliver healthy children without an apparent increase in risk for mother or child.

Enteric-coated mycophenolate sodium: tolerability profile compared with mycophenolate mofetil.

Mycophenolate mofetil is one of the most frequently used immunosuppressive drugs in solid organ transplantation. Although the adverse effect profile of mycophenolate mofetil is comparatively benign, gastrointestinal adverse effects are a major concern. The adverse effects may require a dose reduction or discontinuation, thus limiting its clinical efficacy. Enteric-coated (EC) mycophenolate sodium is a new formulation of mycophenolic acid (MPA) that delivers the active moiety MPA, the same active moiety delivered by mycophenolate mofetil. It has been developed to help protect the upper gastrointestinal tract. It is implied that a reduction of adverse drug effects as well as a reduction of dose may improve efficacy and compliance. Noncompliance is often underestimated in solid organ transplant recipients, and adverse drug effects increase medication nonadherence. Recent clinical trials comparing EC mycophenolate sodium and mycophenolate mofetil in kidney recipients reported similar rates of efficacy and adverse effects. It is noteworthy that systemic MPA exposure is higher with EC mycophenolate sodium than with mycophenolate mofetil, without increased gastrointestinal toxicity. This finding is quite surprising, because part of MPA-associated gastrointestinal toxicity is related to its antiproliferative effect on enterocytes. However, enteric coating of MPA did not markedly reduce the number of gastrointestinal adverse effects. Further studies focusing on dosage, therapeutic drug monitoring and immunosuppressive regimens may reveal benefits of EC mycophenolate sodium for optimal individualised immunosuppression and improved compliance. At present, EC mycophenolate sodium is an alternative immunosuppressant to mycophenolate mofetil in kidney transplant recipients with an almost identical efficacy and safety profile.

Genome-wide association study of primary sclerosing cholangitis identifies new risk loci and quantifies the genetic relationship with inflammatory bowel disease

Primary sclerosing cholangitis (PSC) is a rare progressive disorder leading to bile duct destruction; ∼75% of patients have comorbid inflammatory bowel disease (IBD). We undertook the largest genome-wide association study of PSC (4,796 cases and 19,955 population controls) and identified four new genome-wide significant loci. The most associated SNP at one locus affects splicing and expression of UBASH3A, with the protective allele (C) predicted to cause nonstop-mediated mRNA decay and lower expression of UBASH3A. Further analyses based on common variants suggested that the genome-wide genetic correlation (rG) between PSC and ulcerative colitis (UC) (rG = 0.29) was significantly greater than that between PSC and Crohns disease (CD) (rG = 0.04) (P = 2.55 × 10−15). UC and CD were genetically more similar to each other (rG = 0.56) than either was to PSC (P < 1.0 × 10−15). Our study represents a substantial advance in understanding of the genetics of PSC.

Evaluation of genome-wide loci of iron metabolism in hereditary hemochromatosis identifies PCSK7 as a host risk factor of liver cirrhosis

Genome-wide association studies (GWAS) have revealed genetic determinants of iron metabolism, but correlation of these with clinical phenotypes is pending. Homozygosity for HFE C282Y is the predominant genetic risk factor for hereditary hemochromatosis (HH) and may cause liver cirrhosis. However, this genotype has a low penetrance. Thus, detection of yet unknown genetic markers that identify patients at risk of developing severe liver disease is necessary for better prevention. Genetic loci associated with iron metabolism (TF, TMPRSS6, PCSK7, TFR2 and Chr2p14) in recent GWAS and liver fibrosis (PNPLA3) in recent meta-analysis were analyzed for association with either liver cirrhosis or advanced fibrosis in 148 German HFE C282Y homozygotes. Replication of associations was sought in additional 499 Austrian/Swiss and 112 HFE C282Y homozygotes from Sweden. Only variant rs236918 in the PCSK7 gene (proprotein convertase subtilisin/kexin type 7) was associated with cirrhosis or advanced fibrosis (P = 1.02 × 10(-5)) in the German cohort with genotypic odds ratios of 3.56 (95% CI 1.29-9.77) for CG heterozygotes and 5.38 (95% CI 2.39-12.10) for C allele carriers. Association between rs236918 and cirrhosis was confirmed in Austrian/Swiss HFE C282Y homozygotes (P = 0.014; ORallelic = 1.82 (95% CI 1.12-2.95) but not in Swedish patients. Post hoc combined analyses of German/Swiss/Austrian patients with available liver histology (N = 244, P = 0.00014, ORallelic = 2.84) and of males only (N = 431, P = 2.17 × 10(-5), ORallelic = 2.54) were consistent with the premier finding. Association between rs236918 and cirrhosis was not confirmed in alcoholic cirrhotics, suggesting specificity of this genetic risk factor for HH. PCSK7 variant rs236918 is a risk factor for cirrhosis in HH patients homozygous for the HFE C282Y mutation.

Chronic Portal Vein Thrombosis: Transcapsular Hepatic Collateral Vessels and Communicating Ectopic Varices

PURPOSEnTo assess patients with chronic portal vein thrombosis (PVT) with respect to transcapsular collateral veins, the communication between these veins and ectopic varices, and the cause of PVT.nnnMATERIALS AND METHODSnThis study was approved by the institutional review committees, and written informed consent was obtained. From November 2003 to March 2008, 145 consecutive patients with chronic PVT due to a variety of causes were assessed for transcapsular collaterals and ectopic varices with ultrasonography (US). Analysis of contingency tables was performed with the Fisher exact test.nnnRESULTSnTranscapsular collaterals were detected in 15 (10.3%) of 145 patients with chronic PVT. They were restricted to patients with a history of hepatobilary surgery, severe pancreatitis, or abdominal surgery (n = 21) and were not detected in patients with liver cirrhosis, systemic coagulopathy, extrahepatic malignancy, idiopathic PVT, chronic pancreatitis, or infectious or inflammatory diseases (n = 124) (P < .001). Ectopic varices were infrequent in 70 patients with liver cirrhosis (n = 2, 3%) but were common in 14 patients with PVT after hepatobiliary surgery (n = 9, 64%) (P < .001, odds ratio = 21.4). Direct communication between transcapsular collaterals and ectopic varices was visible in all nine patients in this cohort. In eight of these patients, ectopic varices were found to be the bleeding source in gastrointestinal hemorrhage.nnnCONCLUSIONnTranscapsular collaterals frequently occur in patients with chronic PVT due to hepatobilary surgery or necrotizing pancreatitis. They are associated with ectopic varices; therefore, awareness of transcapsular collaterals in this patient subgroup will help to localize ectopic varices as potential bleeding source.

Small intestine transplantation today

IntroductionIntestinal transplantation has become a life-saving therapy in patients with irreversible loss of intestinal function and complications of total parenteral nutrition.DiscussionThe patient and graft survival rates have improved over the last years, especially after the introduction of tacrolimus and rapamycin. However, intestinal transplantation is more challenging than other types of solid organ transplantation due to its large amount of immune competent cells and its colonization with microorganisms. Moreover, intestinal transplantation is still a low volume procedure with a small number of transplanted patients especially in Germany. A current matter of concern is the late referral of intestinal transplant candidates.ConclusionThus, patients often present after onset of life-threatening complications or advanced cholestatic liver disease. Earlier timing of referral for candidacy might result in further improvement of this technique in the near future.