Showing papers by "Stephan Brand published in 2012"

Host-microbe interactions have shaped the genetic architecture of inflammatory bowel disease

Abstract: Crohn's disease and ulcerative colitis, the two common forms of inflammatory bowel disease (IBD), affect over 2.5 million people of European ancestry, with rising prevalence in other populations. Genome-wide association studies and subsequent meta-analyses of these two diseases as separate phenotypes have implicated previously unsuspected mechanisms, such as autophagy, in their pathogenesis and showed that some IBD loci are shared with other inflammatory diseases. Here we expand on the knowledge of relevant pathways by undertaking a meta-analysis of Crohn's disease and ulcerative colitis genome-wide association scans, followed by extensive validation of significant findings, with a combined total of more than 75,000 cases and controls. We identify 71 new associations, for a total of 163 IBD loci, that meet genome-wide significance thresholds. Most loci contribute to both phenotypes, and both directional (consistently favouring one allele over the course of human history) and balancing (favouring the retention of both alleles within populations) selection effects are evident. Many IBD loci are also implicated in other immune-mediated disorders, most notably with ankylosing spondylitis and psoriasis. We also observe considerable overlap between susceptibility loci for IBD and mycobacterial infection. Gene co-expression network analysis emphasizes this relationship, with pathways shared between host responses to mycobacteria and those predisposing to IBD.

Infliximab does not affect postoperative complication rates in Crohn's patients undergoing abdominal surgery.

Abstract: Background: In patients with Crohn's disease (CD), the effect of anti-tumor necrosis factor alpha (TNF-α) antibody therapy on postoperative complications remains unclear We aimed to determine the effects of infliximab on postoperative complication rates in patients undergoing abdominal surgery for CD Methods: Infliximab-treated CD patients undergoing abdominal surgery were identified in a prospective database Gender- and age-matched CD patients without infliximab treatment served as controls General and complication-related information was retrieved from patient records Results: Forty-eight patients underwent abdominal surgery within 3 months (median 60 days, range 1–90 days) after infliximab administration (56% female, median age 35 years, range 17–66 years) Forty-eight patients without infliximab served as controls (50% female, 39 [17–68] years) Patient characteristics and number of minor complications were comparable between groups: wound infection (infliximab: 19% vs controls: 15%), prolonged postoperative ileus (15% vs 4%), and urinary tract infection (2% vs 0%; all P > 005) No differences were found in major complications: anastomotic leakage (infliximab: 4% vs controls: 13%), abscess formation (6% vs 10%), bowel perforation (2% vs 4%), stoma complication (6% vs 2%), postoperative hemorrhage (8% vs 2%), and enterocutaneous fistula (4% vs 0%; all P > 005) One malnourished infliximab-treated patient with a complicated course of disease died postoperatively after anastomotic leakage, sepsis, and cardiac arrhythmia Eleven infliximab and 10 control patients required reoperation (P > 005) Hospital stay was comparable between groups (infliximab: 13 [5–41] vs controls: 12 [5–54] days; P > 005) Conclusions: Infliximab does not affect postoperative complication rates, suggesting no need to alter surgical management in these patients (Inflamm Bowel Dis 2011;)

PTPN2 Gene Variants Are Associated with Susceptibility to Both Crohn's Disease and Ulcerative Colitis Supporting a Common Genetic Disease Background

Abstract: Genome-wide association studies identified PTPN2 (protein tyrosine phosphatase, non-receptor type 2) as susceptibility gene for inflammatory bowel diseases (IBD). However, the exact role of PTPN2 in Crohn's disease (CD) and ulcerative colitis (UC) and its phenotypic effect are unclear. We therefore performed a detailed genotype-phenotype and epistasis analysis of PTPN2 gene variants. Genomic DNA from 2131 individuals of Caucasian origin (905 patients with CD, 318 patients with UC, and 908 healthy, unrelated controls) was analyzed for two SNPs in the PTPN2 region (rs2542151, rs7234029) for which associations with IBD were found in previous studies in other cohorts. Our analysis revealed a significant association of PTPN2 SNP rs2542151 with both susceptibility to CD (p = 1.95×10⁻⁵; OR 1.49 [1.34-1.79]) and UC (p = 3.87×10⁻², OR 1.31 [1.02-1.68]). Moreover, PTPN2 SNP rs7234029 demonstrated a significant association with susceptibility to CD (p = 1.30×10⁻³; OR 1.35 [1.13-1.62]) and a trend towards association with UC (p = 7.53×10⁻²; OR 1.26 [0.98-1.62]). Genotype-phenotype analysis revealed an association of PTPN2 SNP rs7234029 with a stricturing disease phenotype (B2) in CD patients (p = 6.62×10⁻³). Epistasis analysis showed weak epistasis between the ATG16L1 SNP rs2241879 and PTPN2 SNP rs2542151 (p = 0.024) in CD and between ATG16L1 SNP rs4663396 and PTPN2 SNP rs7234029 (p = 4.68×10⁻³) in UC. There was no evidence of epistasis between PTPN2 and NOD2 and PTPN2 and IL23R. In silico analysis revealed that the SNP rs7234029 modulates potentially the binding sites of several transcription factors involved in inflammation including GATA-3, NF-κB, C/EBP, and E4BP4. Our data confirm the association of PTPN2 variants with susceptibility to both CD and UC, suggesting a common disease pathomechanism for these diseases. Given recent evidence that PTPN2 regulates autophagosome formation in intestinal epithelial cells, the potential link between PTPN2 and ATG16L1 should be further investigated.

Analysis of IL12B Gene Variants in Inflammatory Bowel Disease

Abstract: Background IL12B encodes the p40 subunit of IL-12, which is also part of IL-23. Recent genome-wide association studies identified IL12B and IL23R as susceptibility genes for inflammatory bowel disease (IBD). However, the phenotypic effects and potential gene-gene interactions of IL12B variants are largely unknown.

PTGER4 Expression-Modulating Polymorphisms in the 5p13.1 Region Predispose to Crohn's Disease and Affect NF-κB and XBP1 Binding Sites

Abstract: Background: Genome-wide association studies identified a PTGER4 expression-modulating region on chromosome 5p13.1 as Crohn’s disease (CD) susceptibility region. The study aim was to test this association in a large cohort of patients with inflammatory bowel disease (IBD) and to elucidate genotypic and phenotypic interactions with other IBD genes. Methodology/Principal Findings: A total of 7073 patients and controls were genotyped: 844 CD and 471 patients with ulcerative colitis and 1488 controls were analyzed for the single nucleotide polymorphisms (SNPs) rs4495224 and rs7720838 on chromosome 5p13.1. The study included two replication cohorts of North American (CD: n=684; controls: n=1440) and of German origin (CD: n=1098; controls: n=1048). Genotype-phenotype, epistasis and transcription factor binding analyses were performed. In the discovery cohort, an association of rs4495224 (p=4.10610 25 ; 0.76 [0.67–0.87]) and of rs7720838 (p=6.91610 24 ; 0.81 [0.71–0.91]) with susceptibility to CD was demonstrated. These associations were confirmed in both replication cohorts. In silico analysis predicted rs4495224 and rs7720838 as essential parts of binding sites for the transcription factors NF-kB and XBP1 with higher binding scores for carriers of the CD risk alleles, providing an explanation of how these SNPs might contribute to increased PTGER4 expression. There was no association of the PTGER4 SNPs with IBD phenotypes. Epistasis detected between 5p13.1 and ATG16L1 for CD susceptibility in the discovery cohort (p=5.99610 27 for rs7720838 and rs2241880) could not be replicated in both replication cohorts arguing against a major role of this gene-gene interaction in the susceptibility to CD. Conclusions/Significance: We confirmed 5p13.1 as a major CD susceptibility locus and demonstrate by in silico analysis rs4495224 and rs7720838 as part of binding sites for NF-kB and XBP1. Further functional studies are necessary to confirm the results of our in silico analysis and to analyze if changes in PTGER4 expression modulate CD susceptibility.

Effects of perfusion and cyclic compression on in vitro tissue engineered meniscus implants

Abstract: Purpose The purpose of this study was to investigate the influence of continuous perfusion and mechanical stimulation on bone marrow stromal cells seeded on a collagen meniscus implant. Methods Bone marrow aspirates from 6 donors were amplified in vitro. 10 6 human BMSC were distributed on a collagen meniscus implant. Scaffolds were cultured under static conditions (control) or placed into a bioreactor system where continuous perfusion (10 ml/min) or perfusion and mechanical stimulation (8 h of 10% cyclic compression at 0.5 Hz) were administered daily. After 24 h, 7 and 14 days, cell proliferation, synthesis of procollagen I and III peptide (PIP, PIIIP), histology, and the equilibrium modulus of the constructs were analyzed. Results Proliferation demonstrated a significant increase over time in all groups (p \ 0.001). PIP synthesis was found to increase from 0.1 ± 0.0 U/ml/g protein after 24 h to 2.0 ± 0.5 (perfusion), 3.8 ± 0.3 (mechanical stimulation), and 1.8 ± 0.2 U/ml/g protein (static control, lower than perfusion and mechanical stimulation, p \ 0.05). These differences were also evident after 2 weeks (2.7 ± 0.3, 4.0 ± 0.6, and 1.8 ± 0.2 U/ml/g protein, p \ 0.01); PIIIP synthesis was found to increase from 0.1 ± 0.0 U/ml/g protein after 24 h to 2.9 ± 0.7 (perfusion), 3.1 ± 0.9 (mechanical stimulation), and 1.6 ± 0.3 U/ml/g protein (controls) after 1 week and remained significantly elevated under the influence of perfusion and mechanical stimulation (p \ 0.01) after 2 weeks. Mechanical stimulation increased the equilibrium modulus more than static culture and perfusion after 2 weeks (24.7 ± 7.6; 12.3 ± 3.7; 15.4 ± 2.6 kPa; p \ 0.02). Conclusion Biomechanical stimulation and perfusion have impact on collagen scaffolds seeded with BMSCs. Cell proliferation can be enhanced using continuous perfusion and differentiation is fostered by mechanical

Perifosine-mediated Akt inhibition in neuroendocrine tumor cells: role of specific Akt isoforms

Abstract: The majority of neuroendocrine tumors (NETs) of the gastroenteropancreatic system show aberrant Akt activity. Several inhibitors of the phosphoinositide 3-kinase (PI(3)K)-Akt-mTOR signaling pathway are currently being evaluated in clinical phase II and III studies for the treatment of NETs with promising results. However, the molecular mechanisms and particularly the role of different Akt isoforms in NET signaling are not fully understood. In this study, we examine the effect of Akt inhibition on NET cells of heterogeneous origin. We show that the Akt inhibitor perifosine effectively inhibits Akt phosphorylation and cell viability in human pancreatic (BON1), bronchus (NCI-H727), and midgut (GOT1) NET cells. Perifosine treatment suppressed the phosphorylation of Akt downstream targets such as GSK3α/β, MDM2, and p70S6K and induced apoptosis. To further investigate the role of individual Akt isoforms for NET cell function, we specifically blocked Akt1, Akt2, and Akt3 via siRNA transfection. In contrast to Akt2 knockdown, knockdown of Akt isoforms 1 and 3 decreased phosphorylation levels of GSK3α/β, MDM2, and p70S6K and suppressed NET cell viability and colony-forming capacity. The inhibitory effect of simultaneous downregulation of Akt1 and Akt3 on tumor cell viability was significantly stronger than that caused by downregulation of all Akt isoforms, suggesting a particular role for Akt1 and Akt3 in NET signaling. Akt3 siRNA-induced apoptosis while all three isoform-specific siRNAs impaired BON1 cell invasion. Together, our data demonstrate potent antitumor effects of the pan-Akt inhibitor perifosine on NET cells in vitro and suggest that selective targeting of Akt1 and/or Akt3 might improve the therapeutic potential of Akt inhibition in NET disease.

Iron status and analysis of efficacy and safety of ferric carboxymaltose treatment in patients with inflammatory bowel disease.

Abstract: Background and Aims: We analyzed iron deficiency and the therapeutic response following intravenous ferric carboxymaltose in a large single-center inflammatory bowel disease (IBD) cohort. Methods: 250 IBD patients were retrospectively analyzed for iron deficiency and iron deficiency anemia. A subgroup was analyzed regarding efficacy and side effects of iron supplementation with ferric carboxymaltose. Results: In the cohort (n = 250), 54.4% of the patients had serum iron levels ≤60 µg/dl, 81.2% had ferritin ≤100 ng/ml, and 25.6% had hemoglobin (Hb) of ≤12 g/dl (females) or ≤13 g/dl (males). In the treatment subcohort (n = 80), 83.1% of the patients had iron ≤60 µg/dl, 90.4% had ferritin ≤100 ng/ml, and 66.7% had Hb ≤12/13 g/dl before ferric carboxymaltose treatment. After a median dose of 500 mg ferric carboxymaltose, 74.7% of the patients reached iron >60 µg/dl, 61.6% had ferritin >100 ng/ml, and 90.7% reached Hb >12/13 g/dl at follow-up (p Conclusions: Iron deficiency and anemia are frequent in IBD patients. Treatment with ferric carboxymaltose is efficious, safe and well tolerated in iron-deficient IBD patients.

Injury patterns of seniors in traffic accidents: A technical and medical analysis.

Abstract: AIM: To investigate the actual injury situation of seniors in traffic accidents and to evaluate the different injury patterns. METHODS: Injury data, environmental circumstances and crash circumstances of accidents were collected shortly after the accident event at the scene. With these data, a technical and medical analysis was performed, including Injury Severity Score, Abbreviated Injury Scale and Maximum Abbreviated Injury Scale. The method of data collection is named the German In-Depth Accident Study and can be seen as representative. RESULTS: A total of 4430 injured seniors in traffic accidents were evaluated. The incidence of sustaining severe injuries to extremities, head and maxillofacial region was significantly higher in the group of elderly people compared to a younger age (P Language: en

Homozygosity for the NOD2 p.Leu1007fsX1008 variant is the main genetic predictor for fibrostenotic Crohn's disease.

Abstract: To the Editor: It is with great interest that I read the review of Rieder et al on ‘‘Predictors of fibrostenotic Crohn’s disease’’ in Inflammatory Bowel Diseases. The authors mentioned the role of genetic factors, in particular NOD2, which was the only gene significantly associated with intestinal stenosis in the recent European ImmunoChip study. There are three additional points worth mentioning regarding the role of NOD2 mutations in the development of fibrostenotic Crohn’s disease (CD). First, while two NOD2 mutations have a high specificity for predicting complicated CD, a single NOD2 mutation has relatively little sensitivity and only moderate specificity for predicting fibrostenotic and complicated CD. In a very recent meta-analysis, which included 49 studies with 8893 subjects including 2897 carriers of NOD2 mutations, the presence of a single NOD2 mutation predicted only an 8% increase in the risk for complicated disease (defined as stricturing phenotype B2 or penetrating phenotype B3). The authors of this meta-analysis therefore concluded that the presence of only one mutated NOD2 allele has a very limited prognostic value predicting complicated CD behavior. However, there was a 41% increase for the risk for complicated disease with two NOD2 mutations. Moreover, the presence of two NOD2 mutations had 98% specificity for complicated disease. The pooled relative risk (RR) of stricturing disease with the presence of any (one or more) NOD2 mutations was 1.33 (95% confidence interval [CI] 1.15–1.55; P < 0.001). Although other NOD2 mutations may contribute to a complicated disease behavior, the three main CDassociated NOD2 mutations (p.R702W, p.G908R, p.Leu1007fsX1008) are also considered the three main NOD2 mutations modifying CD behavior and were included into this meta-analysis. Second, we provided evidence that homozygosity especially for the NOD2 variant p.Leu1007fsX1008 results in ileal fibrostenosis. The recent NOD2 meta-analysis was limited by the fact that only 12 studies had sufficient data to analyze for individual NOD2 mutations and this meta-analysis did not have enough data to differentiate between heterozygous and homozygous carriers of individual mutations to analyze for fibrostenotic CD. Given these limitations, only an association of fibrostenotic CD with NOD2 p.G908R carrier status was found in this meta-analysis (RR: 1.90, 95% CI 1.17–3.07; P 1⁄4 0.009). In contrast, in one of the most detailed phenotypic analysis of CD patients with NOD2 mutations, including 19 CD patients with two p.Leu1007fsX1008 mutations (identified among 445 IBD patients), we show that all homozygous carriers of the p.Leu1007fsX1008 NOD2 mutation with CD develop fibrostenotic disease in the terminal ileum (Table 1). 73.7% of these patients had to undergo stricture-related surgery. Of these patients, 78.6% developed restenoses after surgical resection. We confirmed these data in a prospective study in which the p.Leu1007fsX1008 variant was associated with an increased risk of intestinal stenosis (odds ratio [OR] 1⁄4 12.00, CI 3.47–41.54, P 1⁄4 0.00042, Bonferroni corrected). After publication of these studies, we observed the same phenotype in a similar-sized replication CD cohort of homozygous carriers of the p.Leu1007fsX1008 mutation (unpubl. obs.), suggesting that these patients would be a primary target group for a personalized early top-down therapeutic strategy to prevent surgical interventions. Third, we recently demonstrated that fibrostenosis is an important risk factor for fistulizing CD. Therefore, CD patients with fistulas not improving under efficacious therapy such as antitumor necrosis factor (TNF) antibodies should be screened for intestinal stenosis. In our retrospective study of 333 CD patients, concomitant stenosis was diagnosed in 125 patients with fistulas. In this study, the positive predictive value (PPV) was 86.2% for fistulas predicting intestinal stenosis. In logistic regression analysis, the presence of fistulas (OR 4.51; 95% CI 2.54–8.01, P 1⁄4 2.68 10 ) and disease duration (OR 1.09; 95% CI 1.05– 1.13; P 1⁄4 3.19 10 ) were strongly associated with intestinal stenosis. TABLE 1. Phenotypic Characteristics.

Intraprosthetic fixation techniques in the treatment of periprosthetic fractures-A biomechanical study.

Abstract: AIM: To develop new fixation techniques for the treatment of periprosthetic fractures using intraprosthetic screw fixation with inserted threaded liners. METHODS: A Vancouver B1 periprosthetic fracture was simulated in femur prosthesis constructs using sawbones and cemented regular straight hip stems. Fixation was then performed with either unicortical locked-screw plating using the less invasive stabilization system-plate or with intraprosthetic screw fixation using inserted liners. Two experimental groups were formed using either prostheses made of titanium alloy or prostheses made of cobalt chrome alloy. Fixation stability was compared in an axial load-to-failure model. Drilling was performed using a specially invented prosthesis drill with constantly applied internal cooling. RESULTS: The intraprosthetic fixation model with titanium prostheses was superior to the unicortical locked-screw fixation in all tested devices. The intraprosthetic fixation model required 10 456 N ± 1892 N for failure and the unicortical locked-screw plating required 7649 N ± 653 N (P < 0.05). There was no significant difference between the second experimental group and the control group. CONCLUSION: Intraprosthetic screw anchorage with special threaded liners enhances the primary stability in treating periprosthetic fractures by internal fixation.

Dominant disease-causing effect of NOD2 mutations in a family with all family members affected by Crohn's disease.

Abstract: With great interest we read the recent review of Thompson and Lees on ‘‘Genetics in ulcerative colitis’’ in Inflammatory Bowel Diseases. A very recent meta-analysis of genome-wide association studies (GWAS) identified additional susceptibility genes for ulcerative colitis (UC). So far, there are at least 47 risk variants for UC and 71 susceptibility gene variants for Crohn’s disease (CD), with a large overlap between CD and UC susceptibility genes. However, the majority of these risk genes has only a small effect on inflammatory bowel disease (IBD) risk, with odds ratios of well below 1.3. Therefore, the clinical importance of genotyping is currently discussed controversially. In contrast, we and others previously demonstrated a unique, severe disease phenotype of homozygous carriers of the p.Leu1007fsX1008 NOD2 mutation which leads to ileal stenosis requiring surgical intervention in almost all CD patients homozygous for this mutation. Moreover, NOD2 is one of the very few genes with a strong disease-causing effect in CD. Here we describe a family in which all four family members were diagnosed with CD and are all affected by CD-associated NOD2 mutations. Moreover, the mother and both children were heterozygous carriers of the p.Leu1007fsX1008 NOD2 mutation (Fig. 1A), which highlights the exceptional importance of this mutation in clinical practice. To our knowledge, this is the first report of a dominant model of inheritance of NOD2 mutations resulting in CD in all family members. The main disease characteristics of this family are shown in Table 1. The first patient treated at our IBD center was the 22-year-old daughter of this family who was diagnosed with CD at the age of 7 years. Her disease onset was characterized by severe active ileitis resulting in ileal stenosis and enteroenteral and retroperitoneal fistulas FIGURE 1. (A) Dominant disease-causing effect of NOD2 mutations in a family with all four family members diagnosed with CD. All family members are carriers of CD-associated NOD2 mutations. (B) Gastroscopy in the index patient (daughter) demonstrated gastric erosions and postinflammatory stenosis in the duodenum. (C) Colonoscopy in the index patient revealed erosive lesions at the anastomosis. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

Traumatic dissection of carotid arteries caused by high energy motorcycle accident

Abstract: Injuries of internal carotid arteries caused by high energy trauma are rare but often combined with poor outcome. Blunt trauma to the head and neck as well as the use of newer motorcycle helmets together with crash circumstances should promptly lead to a differentiated polytrauma management with expansion of radiologic diagnostics. This could lead to a reduction of overlooked dissections and an increase in promptly and correctly treated injuries.