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42
result(s) for
"Buch, Stephan"
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Loss of hepatic Mboat7 leads to liver fibrosis
by
Aigner, Elmar
,
Chavakis, Triantafyllos
,
Brosch, Mario
in
Acyltransferase
,
Acyltransferases - deficiency
,
Acyltransferases - genetics
2021
ObjectiveThe rs641738C>T variant located near the membrane-bound O-acyltransferase domain containing 7 (MBOAT7) locus is associated with fibrosis in liver diseases, including non-alcoholic fatty liver disease (NAFLD), alcohol-related liver disease, hepatitis B and C. We aim to understand the mechanism by which the rs641738C>T variant contributes to pathogenesis of NAFLD.DesignMice with hepatocyte-specific deletion of MBOAT7 (Mboat7Δhep) were generated and livers were characterised by histology, flow cytometry, qPCR, RNA sequencing and lipidomics. We analysed the association of rs641738C>T genotype with liver inflammation and fibrosis in 846 NAFLD patients and obtained genotype-specific liver lipidomes from 280 human biopsies.ResultsAllelic imbalance analysis of heterozygous human liver samples pointed to lower expression of the MBOAT7 transcript on the rs641738C>T haplotype. Mboat7Δhep mice showed spontaneous steatosis characterised by increased hepatic cholesterol ester content after 10 weeks. After 6 weeks on a high fat, methionine-low, choline-deficient diet, mice developed increased hepatic fibrosis as measured by picrosirius staining (p<0.05), hydroxyproline content (p<0.05) and transcriptomics, while the inflammatory cell populations and inflammatory mediators were minimally affected. In a human biopsied NAFLD cohort, MBOAT7 rs641738C>T was associated with fibrosis (p=0.004) independent of the presence of histological inflammation. Liver lipidomes of Mboat7Δhep mice and human rs641738TT carriers with fibrosis showed increased total lysophosphatidylinositol levels. The altered lysophosphatidylinositol and phosphatidylinositol subspecies in MBOAT7Δhep livers and human rs641738TT carriers were similar.ConclusionMboat7 deficiency in mice and human points to an inflammation-independent pathway of liver fibrosis that may be mediated by lipid signalling and a potentially targetable treatment option in NAFLD.
Journal Article
Aberrant DNA methylation of ADAMTS16 in colorectal and other epithelial cancers
by
Brosch, Mario
,
Siebert, Reiner
,
Kordowski, Felix
in
ADAMTS Proteins - genetics
,
ADAMTS Proteins - metabolism
,
ADAMTS16
2018
Background
ADAMs (a disintegrin and metalloproteinase) have long been associated with tumor progression. Recent findings indicate that members of the closely related ADAMTS (ADAMs with thrombospondin motifs) family are also critically involved in carcinogenesis. Gene silencing through DNA methylation at CpG loci around e.g. transcription start or enhancer sites is a major mechanism in cancer development. Here, we aimed at identifying genes of the ADAM and ADAMTS family showing altered DNA methylation in the development or colorectal cancer (CRC) and other epithelial tumors.
Methods
We investigated potential changes of DNA methylation affecting
ADAM
and
ADAMTS
genes in 117 CRC, 40 lung cancer (LC) and 15 oral squamous-cell carcinoma (SCC) samples. Tumor tissue was analyzed in comparison to adjacent non-malignant tissue of the same patients. The methylation status of 1145 CpGs in 51
ADAM
and
ADAMTS
genes was measured with the HumanMethylation450 BeadChip Array. ADAMTS16 protein expression was analyzed in CRC samples by immunohistochemistry.
Results
In CRC, we identified 72 CpGs in 18 genes which were significantly affected by hyper- or hypomethylation in the tumor tissue compared to the adjacent non-malignant tissue. While notable/frequent alterations in methylation patterns within
ADAM
genes were not observed, conspicuous changes were found in
ADAMTS16
and
ADAMTS2
. To figure out whether these differences would be CRC specific, additional LC and SCC tissue samples were analyzed. Overall, 78 differentially methylated CpGs were found in LC and 29 in SCC. Strikingly, 8 CpGs located in the
ADAMTS16
gene were commonly differentially methylated in all three cancer entities. Six CpGs in the promoter region were hypermethylated, whereas 2 CpGs in the gene body were hypomethylated indicative of gene silencing. In line with these findings, ADAMTS16 protein was strongly expressed in globlet cells and colonocytes in control tissue but not in CRC samples. Functional in vitro studies using the colorectal carcinoma cell line HT29 revealed that ADAMTS16 expression restrained tumor cell proliferation.
Conclusions
We identified
ADAMTS16
as novel gene with cancer-specific promoter hypermethylation in CRC, LC and SCC patients implicating
ADAMTS16
as potential biomarker for these tumors. Moreover, our results provide evidence that
ADAMTS16
may have tumor suppressor properties.
Journal Article
A genome-wide association scan identifies the hepatic cholesterol transporter ABCG8 as a susceptibility factor for human gallstone disease
2007
With an overall prevalence of 10–20%, gallstone disease (cholelithiasis) represents one of the most frequent and economically relevant health problems of industrialized countries
1
,
2
. We performed an association scan of >500,000 SNPs in 280 individuals with gallstones and 360 controls. A follow-up study of the 235 most significant SNPs in 1,105 affected individuals and 873 controls replicated the disease association of SNP A-1791411 in
ABCG8
(allelic
P
value
P
CCA
= 4.1 × 10
−9
), which was subsequently attributed to coding variant rs11887534 (D19H). Additional replication was achieved in 728 German (
P
= 2.8 × 10
−7
) and 167 Chilean subjects (
P
= 0.02). The overall odds ratio for D19H carriership was 2.2 (95% confidence interval: 1.8–2.6,
P
= 1.4 × 10
−14
) in the full German sample. Association was stronger in subjects with cholesterol gallstones (odds ratio = 3.3), suggesting that His19 might be associated with a more efficient transport of cholesterol into the bile.
Journal Article
The regulation of artificial intelligence in intensive care units: from narrow tools to generalist systems
2026
Artificial intelligence (AI) is increasingly explored for use in intensive care units. While most approved AI devices use narrow models, research is shifting towards generalist systems based on large language models and agentic AI. In this perspective, we propose a five-paradigm framework that shows how regulatory complexity rises with AI functionality and scale. As current regulatory frameworks are device-centric, new approaches like agentic oversight are needed for orchestrating AI systems.
Journal Article
Recurrence of gallstones after cholecystectomy is associated with ABCG5/8 genotype
2013
Background
Gallstone disease is a frequent and economically highly relevant disorder, with cholecystectomy representing one of the most frequently performed operations world-wide. Gallstone recurrence after cholecystectomy is associated with complications such as biliary sepsis and pancreatitis. As yet, variant ABCG8-D19H is the most widely recognized genetic risk factor for gallstone disease. The aim of the study is to investigate whether ABCG8-D19H is associated with gallstone recurrence after cholecystectomy.
Methods
Two thousand three hundred and eight patients from an earlier study of gallstone risk factors were re-contacted by mail, leading to 1,915 patients with available clinical and genetic information. Symptomatic gallstone recurrence was established if it occurred more than six months after surgery. Median follow-up time after cholecystectomy was eight years.
Results
Gallstones recurred in 37 patients (1.9 %). ABCG-D19H was found to be significantly associated with gallstone recurrence (
p
= 0.034). The allelic odds ratio was 1.97 (95 % CI 1.12–∞). In a multivariate logistic regression analysis adjusted for age, sex, BMI and type of surgery, ABCG8-D19H remained a significant predictor, both in the total cohort (
p
= 0.024) and in the subgroup for whom information on type and scheduling of surgery was available (
N
= 1,650,
p
= 0.020).
Conclusions
ABCG8-D19H is a predictor of gallstone recurrence, a major long term postoperative biliary complication. Moreover, the observed association also reemphasizes the importance of the sterolin transporter for stone formation.
Journal Article
The rs429358 Locus in Apolipoprotein E Is Associated With Hepatocellular Carcinoma in Patients With Cirrhosis
by
Nischalke, Hans Dieter
,
Lutz, Philip L.
,
Stickel, Felix
in
Alcohol
,
Apolipoproteins
,
Apolipoproteins E - genetics
2022
The host genetic background for hepatocellular carcinoma (HCC) is incompletely understood. We aimed to determine if four germline genetic polymorphisms, rs429358 in apolipoprotein E (APOE), rs2642438 in mitochondrial amidoxime reducing component 1 (MARC1), rs2792751 in glycerol‐3‐phosphate acyltransferase (GPAM), and rs187429064 in transmembrane 6 superfamily member 2 (TM6SF2), previously associated with progressive alcohol‐related and nonalcoholic fatty liver disease, are also associated with HCC. Four HCC case‐control data sets were constructed, including two mixed etiology data sets (UK Biobank and FinnGen); one hepatitis C virus (HCV) cohort (STOP‐HCV), and one alcohol‐related HCC cohort (Dresden HCC). The frequency of each variant was compared between HCC cases and cirrhosis controls (i.e., patients with cirrhosis without HCC). Population controls were also considered. Odds ratios (ORs) associations were calculated using logistic regression, adjusting for age, sex, and principal components of genetic ancestry. Fixed‐effect meta‐analysis was used to determine the pooled effect size across all data sets. Across four case‐control data sets, 2,070 HCC cases, 4,121 cirrhosis controls, and 525,779 population controls were included. The rs429358:C allele (APOE) was significantly less frequent in HCC cases versus cirrhosis controls (OR, 0.71; 95% confidence interval [CI], 0.61‐0.84; P = 2.9 × 10−5). Rs187429064:G (TM6SF2) was significantly more common in HCC cases versus cirrhosis controls and exhibited the strongest effect size (OR, 2.03; 95% CI, 1.45‐2.86; P = 3.1 × 10−6). In contrast, rs2792751:T (GPAM) was not associated with HCC (OR, 1.01; 95% CI, 0.90‐1.13; P = 0.89), whereas rs2642438:A (MARC1) narrowly missed statistical significance (OR, 0.91; 95% CI, 0.84‐1.00; P = 0.043). Conclusion: This study associates carriage of rs429358:C (APOE) with a reduced risk of HCC in patients with cirrhosis. Conversely, carriage of rs187429064:G in TM6SF2 is associated with an increased risk of HCC in patients with cirrhosis.
Journal Article
A Comprehensive Investigation on Common Polymorphisms in the MDR1/ABCB1 Transporter Gene and Susceptibility to Colorectal Cancer
by
Hoffmeister, Michael
,
Novotny, Jan
,
Völzke, Henry
in
ABC transporters
,
Adenosine triphosphate
,
Adult
2012
ATP Binding Cassette B1 (ABCB1) is a transporter with a broad substrate specificity involved in the elimination of several carcinogens from the gut. Several polymorphic variants within the ABCB1 gene have been reported as modulators of ABCB1-mediated transport. We investigated the impact of ABCB1 genetic variants on colorectal cancer (CRC) risk. A hybrid tagging/functional approach was performed to select 28 single nucleotide polymorphisms (SNPs) that were genotyped in 1,321 Czech subjects, 699 CRC cases and 622 controls. In addition, six potentially functional SNPs were genotyped in 3,662 German subjects, 1,809 cases and 1,853 controls from the DACHS study. We found that three functional SNPs (rs1202168, rs1045642 and rs868755) were associated with CRC risk in the German population. Carriers of the rs1202168_T and rs868755_T alleles had an increased risk for CRC (P(trend) = 0.016 and 0.029, respectively), while individuals bearing the rs1045642_C allele showed a decreased risk of CRC (P(trend) = 0.022). We sought to replicate the most significant results in an independent case-control study of 3,803 subjects, 2,169 cases and 1,634 controls carried out in the North of Germany. None of the SNPs tested were significantly associated with CRC risk in the replication study. In conclusion, in this study of about 8,800 individuals we show that ABCB1 gene polymorphisms play at best a minor role in the susceptibility to CRC.
Journal Article
A genome-wide association study confirms PNPLA3 and identifies TM6SF2 and MBOAT7 as risk loci for alcohol-related cirrhosis
2015
Felix Stickel and colleagues report the results of a genome-wide association study of alcohol-related cirrhosis. They confirm
PNPLA3
as a susceptibility locus and identify new association signals in
MBOAT7
and
TM6SF2
.
Alcohol misuse is the leading cause of cirrhosis and the second most common indication for liver transplantation in the Western world
1
,
2
,
3
. We performed a genome-wide association study for alcohol-related cirrhosis in individuals of European descent (712 cases and 1,426 controls) with subsequent validation in two independent European cohorts (1,148 cases and 922 controls). We identified variants in the
MBOAT7
(
P
= 1.03 × 10
−9
) and
TM6SF2
(
P
= 7.89 × 10
−10
) genes as new risk loci and confirmed rs738409 in
PNPLA3
as an important risk locus for alcohol-related cirrhosis (
P
= 1.54 × 10
−48
) at a genome-wide level of significance. These three loci have a role in lipid processing, suggesting that lipid turnover is important in the pathogenesis of alcohol-related cirrhosis.
Journal Article
The MLH1 c.1852₁853delinsGC variant in colorectal cancer: genetic association study in 18,723 individuals
by
Castells, Antoni
,
Xicola, Rosa M
,
Veneroni, Silvia
in
Biology and Life Sciences
,
Colorectal cancer
,
Development and progression
2014
Colorectal cancer is one of the most frequent neoplasms and an important cause of mortality in the developed world. Mendelian syndromes account for about 5% of the total burden of CRC, being Lynch syndrome and familial adenomatous polyposis the most common forms. Lynch syndrome tumors develop mainly as a consequence of defective DNA mismatch repair associated with germline mutations in MLH7, MSH2, MSH6 and PMS2. A significant proportion of variants identified by screening these genes correspond to missense or noncoding changes without a clear pathogenic consequence, and they are designated as \"variants of uncertain significance\", being the c.1852_1853delinsGC (p.K618A) variant in the MLH7 gene a clear example. The implication of this variant as a low-penetrance risk variant for CRC was assessed in the present study by performing a case-control study within a large cohort from the COGENT consortium-COST Action BM1206 including 18,723 individuals (8,055 colorectal cancer cases and 10,668 controls) and a case-only genotype-phenotype correlation with several clinical and pathological characteristics restricted to the Epicolon cohort. Our results showed no involvement of this variant as a low-penetrance variant for colorectal cancer genetic susceptibility and no association with any clinical and pathological characteristics including family history for this neoplasm or Lynch syndrome.
Journal Article