Use of cholinesterase activity as a biomarker of pesticide exposure used on Costa Rican banana plantations in the native tropical fish Astyanax aeneus (Günther, 1860)

In Costa Rica, thousands of tones of agricultural pesticides have been used for decades and their use is continuously increasing due to intensive and expanding production of coffee, pineapple, rice, ornamental plants and bananas. The objective of this study was to evaluate whether choline esterase (ChE) activity could be used as a biomarker of exposure to pesticides in the Costa Rican native fish Astyanax aeneus (characidae). Three methods used in order to evaluate the ChE biomarker were as follows: Laboratory studies where A. aeneus was exposed to organophosphate pesticide (ethoprophos); In situ 48 hr exposure assessment using caging experiments with fish exposed upstream and downstream of banana plantations and ChE activity estimation of in fish captured directly at sites with different degrees of pesticide exposure. Results from the laboratory studies showed that ChE activity in both brain and muscle tissue was significantly lower in fish exposed to ethoprophos than in controls. Fish from the caging experiments showed no difference in ChE activity neither in brain nor in muscle tissue between the four tested sites and was attributed to the short duration of the exposure. Asignificant difference in ChE activity was determined in muscle of fish captured from Laguna Madre de Dios compared to fish from Canal Batán. Although our laboratory results revealed that ChE activity in A. aeneus was highly responsive to ethoprophos, results from field experiments were less conclusive and showed that the captured fish showed large variability in ChE activity and that more research is needed before ChE activity can be used as reliable biomarker of pesticide exposure.

Pregnane X receptor (PXR/NR1I2) gene haplotypes modulate susceptibility to inflammatory bowel disease

BACKGROUND

The pregnane X receptor (PXR/NR1I2) is an important regulator of xenobiotic metabolism and intestinal integrity. However, there are controversial studies on the role of PXR/NR1I2 in inflammatory bowel disease (IBD). We therefore initiated the largest analysis to date on PXR/NR1I2 gene variants in IBD patients.

METHODS

Genomic DNA from 2823 individuals of Caucasian origin including 859 patients with Crohn's disease (CD), 464 patients with ulcerative colitis (UC), and 1500 healthy, unrelated controls was analyzed for eight PXR/NR1I2 single nucleotide polymorphisms (SNPs) (rs12721602 (-25564), rs3814055 (-25385), rs1523128 (-24756), rs1523127 (-24381), rs45610735 = p.Gly36Arg (+106), rs6785049 (+7635), rs2276707 (+8055), and rs3814057 (+11156)). In addition, detailed haplotype and genotype-phenotype analyses were performed.

RESULTS

The PXR/NR1I2 SNP rs2276707 was weakly associated with UC susceptibility (P = 0.01; odds ratio [OR] 1.27 [1.06-1.52]). None of the other PXR/NR1I2 SNPs were associated with UC or CD susceptibility. However, several rare PXR/NR1I2 haplotypes were highly associated with CD susceptibility. In CD, the strongest disease association was found for a haplotype consisting of the SNPs rs12721602-rs3814055-rs1523128-rs1523127-rs12721607-rs6785049-rs2276707-rs3814057 (omnibus P-value: 6.50 × 10(-15)) which was found in two separate cohorts (cohort I = discovery cohort: CD: n = 492, controls: n = 793; P = 4.51 × 10(-17); Bonferroni corrected: P = 1.27 × 10(-15); cohort II = replication cohort: CD: n = 367, controls: n = 707; P = 7.12 × 10(-4); P(corr) = 1.99 × 10(-2)).

CONCLUSIONS

Several PXR/NR1I2 haplotypes contribute to CD susceptibility, suggesting a role for PXR in the IBD pathogenesis of a certain patient subcohort. Given the accumulating evidence for an important role of PXR in intestinal inflammation, further analyses are required to investigate the functional and pharmacogenetic implications of these PXR/NR1I2 gene variants in IBD.

Formation of antinuclear and double-strand DNA antibodies and frequency of lupus-like syndrome in anti-TNF-α antibody-treated patients with inflammatory bowel disease

BACKGROUND

Anti-tumor necrosis factor (TNF) therapy used in patients with inflammatory bowel disease (IBD) has been associated with induction of autoantibodies including antinuclear antibodies (ANA), double-strand (ds) DNA antibodies, and the occurrence of lupus-like syndrome (LLS). However, the clinical relevance of autoantibody formation and predictive factors are unclear.

METHODS

180 IBD patients treated with anti-TNF antibodies (infliximab or adalimumab, or infliximab and adalimumab consecutively) were analyzed regarding ANA and dsDNA antibody values and the development of LLS, including factors predicting the development of LLS.

RESULTS

In all, 44.4% of anti-TNF-treated patients had ANA titers ≥1:240, while 15.6% had dsDNA serum levels ≥9 U/mL. However, only a minority of these patients experienced clinical symptoms of LLS; 8.9% presented with mild lupus-like symptoms with no need for intervention; 1.1% had severe symptoms consistent with LLS requiring immediate stop of anti-TNF therapy. Multivariate logistic regression analyses identified age as an independent risk factor for developing ANA ≥1:240 (P < 0.001) and LLS (P = 0.002), while concomitant immunosuppressive therapy was protective against autoantibody formation (ANA: P = 0.05) and LLS development (P = 0.04). There was a significant association between dsDNA antibody values ≥9 U/mL and LLS (P = 0.02) but not between ANA titers and LLS.

CONCLUSIONS

dsDNA antibody levels ≥9 U/mL, but not ANA titers ≥1:240, are associated with clinical symptoms of LLS. IBD patients of higher age treated with anti-TNF-α antibodies are at increased risk for development of ANA and LLS, while concomitant immunosuppressive therapy may have a protective effect.

The NOD2 single nucleotide polymorphisms rs2066843 and rs2076756 are novel and common Crohn's disease susceptibility gene variants

Background

The aims were to analyze two novel NOD2 variants (rs2066843 and rs2076756) in a large cohort of patients with inflammatory bowel disease and to elucidate phenotypic consequences.

Methodology/Principal Findings

Genomic DNA from 2700 Caucasians including 812 patients with Crohn's disease (CD), 442 patients with ulcerative colitis (UC), and 1446 healthy controls was analyzed for the NOD2 SNPs rs2066843 and rs2076756 and the three main CD-associated NOD2 variants p.Arg702Trp (rs2066844), p.Gly908Arg (rs2066847), and p.Leu1007fsX1008 (rs2066847). Haplotype and genotype-phenotype analyses were performed. The SNPs rs2066843 (p = 3.01×10⁻⁵, OR 1.48, [95% CI 1.23-1.78]) and rs2076756 (p = 4.01×10⁻⁶; OR 1.54, [95% CI 1.28-1.86]) were significantly associated with CD but not with UC susceptibility. Haplotype analysis revealed a number of significant associations with CD susceptibility with omnibus p values <10⁻¹⁰. The SNPs rs2066843 and rs2076756 were in linkage disequilibrium with each other and with the three main CD-associated NOD2 mutations (D'>0.9). However, in CD, SNPs rs2066843 and rs2076756 were more frequently observed than the other three common NOD2 mutations (minor allele frequencies for rs2066843 and rs2076756: 0.390 and 0.380, respectively). In CD patients homozygous for these novel NOD2 variants, genotype-phenotype analysis revealed higher rates of a penetrating phenotype (rs2076756: p = 0.015) and fistulas (rs2076756: p = 0.015) and significant associations with CD-related surgery (rs2076756: p = 0.003; rs2066843: p = 0.015). However, in multivariate analysis only disease localization (p<2×10⁻¹⁶) and behaviour (p = 0.02) were significantly associated with the need for surgery.

Conclusion/Significance

The NOD2 variants rs2066843 and rs2076756 are novel and common CD susceptibility gene variants.

Disease activity, ANCA, and IL23R genotype status determine early response to infliximab in patients with ulcerative colitis

OBJECTIVES

We analyzed the efficacy and safety of the antitumor necrosis factor-alpha antibody infliximab (IFX) for induction therapy in patients with moderate-to-severe ulcerative colitis (UC) in a large single-center cohort.

METHODS

A total of 90 UC patients treated with IFX for 14 weeks were analyzed retrospectively. Colitis activity index (CAI) and markers of inflammation were measured during IFX induction therapy. Genotyping for UC-associated variants in the IL23R gene and in the IL2/IL21 region was performed.

RESULTS

At week 2 (after the first IFX infusion), 64.1% of IFX-treated patients had clinical response to IFX and 52.6% were in remission. At week 14 (after three infusions), 61.0% showed clinical response and 52.5% were in remission. The mean CAI decreased significantly from 10.4 points at week 0 to 5.1 at week 2 (P<0.001), to 4.4 at week 6 (P<0.001), and to 5.0 at week 14 (P<0.001). Similarly, IFX therapy significantly decreased C-reactive protein levels and leukocyte counts (P=0.01 and P=0.001 at week 2 and week 0, respectively). Multivariate regression analysis identified high CAI before IFX therapy (P=0.01) and negative antineutrophil cytoplasmatic autoantibody (ANCA) status (P=0.01) as independent positive predictors for response to IFX. Homozygous carriers of inflammatory bowel disease (IBD) risk-increasing IL23R variants were more likely to respond to IFX than were homozygous carriers of IBD risk-decreasing IL23R variants (74.1 vs. 34.6%; P=0.001). No serious adverse IFX-related events requiring hospitalization were recorded.

CONCLUSIONS

Our findings suggest that IFX therapy is safe and effective in patients with moderate-to-severe UC. A high CAI before IFX therapy, ANCA seronegativity, and the IL23R genotype were predictors of early response to IFX.

The cannabinoid 1 receptor (CNR1) 1359 G/A polymorphism modulates susceptibility to ulcerative colitis and the phenotype in Crohn's disease

BACKGROUND

Recent evidence suggests a crucial role of the endocannabinoid system, including the cannabinoid 1 receptor (CNR1), in intestinal inflammation. We therefore investigated the influence of the CNR1 1359 G/A (p.Thr453Thr; rs1049353) single nucleotide polymorphism (SNP) on disease susceptibility and phenotype in patients with ulcerative colitis (UC) and Crohn's disease (CD).

METHODS

Genomic DNA from 579 phenotypically well-characterized individuals was analyzed for the CNR1 1359 G/A SNP. Amongst these were 166 patients with UC, 216 patients with CD, and 197 healthy controls.

RESULTS

Compared to healthy controls, subjects A/A homozygous for the CNR1 1359 G/A SNP had a reduced risk to develop UC (p = 0.01, OR 0.30, 95% CI 0.12-0.78). The polymorphism did not modulate CD susceptibility, but carriers of the minor A allele had a lower body mass index than G/G wildtype carriers (p = 0.0005). In addition, homozygous carriers of the G allele were more likely to develop CD before 40 years of age (p = 5.9x10(-7)) than carriers of the A allele.

CONCLUSION

The CNR1 p.Thr453Thr polymorphism appears to modulate UC susceptibility and the CD phenotype. The endocannabinoid system may influence the manifestation of inflammatory bowel diseases, suggesting endocannabinoids as potential target for future therapies.

The role of fatty acid hydrolase gene variants in inflammatory bowel disease

BACKGROUND

Recent studies suggest a role for the endocannabinoid system, including fatty acid amide hydrolase (FAAH), in intestinal inflammation.

AIM

To analyse FAAH expression and the FAAH 385 C/A (p.Pro129Thr; rs324420) single nucleotide polymorphism (SNP) in-patients with Crohn's disease (CD) and ulcerative colitis (UC).

PATIENTS AND METHODS

Genomic DNA from 1008 individuals (CD: n = 435; UC: n = 167; controls: n = 406) was analysed for the FAAH 385 C/A SNP. We determined FAAH mRNA expression by quantitative PCR in CD and UC lesions as well as in intestinal epithelial cells (IECs).

RESULTS

There were no significant differences regarding the frequency of this SNP in the three study groups (CD, UC, controls). However, CD patients homozygous for the FAAH p.Pro129Thr polymorphism were more likely to develop a severe disease phenotype associated with fistulas (P = 0.03, OR 3.12, 95% CI 1.08-8.98) and extra-intestinal manifestations (P = 0.005, OR 4.29, CI 1.49-12.35). In UC, homozygous carriers had an earlier disease onset than wild-type carriers (P = 0.01). FAAH mRNA expression correlated with IL-8 mRNA expression in CD lesions (r = 0.53). However, pro-inflammatory stimuli did not significantly increase FAAH mRNA expression in IECs.

CONCLUSION

The FAAH p.Pro129Thr polymorphism may modulate the CD phenotype.

Role of the novel Th17 cytokine IL-17F in inflammatory bowel disease (IBD): upregulated colonic IL-17F expression in active Crohn's disease and analysis of the IL17F p.His161Arg polymorphism in IBD

BACKGROUND

Interleukin (IL)-17F, produced in IL-23R-expressing Th17 cells, is a novel member of the IL-17 cytokine family. Given the association of IL23R with inflammatory bowel disease (IBD), we characterized the role of IL-17F in IBD including its intestinal gene expression and the effect of the IL17F p.His161Arg polymorphism on disease susceptibility and phenotype of Crohn's disease (CD) and ulcerative colitis (UC). In addition, we analyzed the IL17F p.His161Arg polymorphism for potential epistasis with IL23R and NOD2/CARD15 variants.

METHODS

Intestinal IL-17F mRNA expression was measured by quantitative polymerase chain reaction (PCR). Genomic DNA from 1682 individuals (CD: n = 499; UC: n = 216; controls: n = 967) was analyzed for the presence of the IL17F p.His161Arg polymorphism, the 3 NOD2 variants, p.Arg702Trp, p.Gly908Arg, and p.Leu1007fsX1008, and 10 CD-associated IL23R variants.

RESULTS

Intestinal IL-17F mRNA expression was 4.4-fold increased in inflamed colonic lesions compared to uninflamed biopsies in CD (P = 0.016) but not in UC. However, the mean intestinal IL-17F mRNA expression was higher in UC than in CD (P < 0.0001). The IL17F p.His161Arg substitution was observed with similar frequencies in IBD patients and controls and was not associated with a certain disease phenotype, but weakly associated with a low body mass index (BMI; P = 0.009) and an earlier age of disease onset (P = 0.039) in UC. There was no evidence for epistasis between the IL17F p.His161Arg polymorphism and IBD-associated single nucleotide polymorphisms within the IL23R gene.

CONCLUSIONS

Intestinal IL17F gene expression is increased in active CD. The IL17F p.His161Arg polymorphism is not associated with IBD susceptibility and has no epistatic interaction with CD-associated IL23R variants.

The ATG16L1 gene variants rs2241879 and rs2241880 (T300A) are strongly associated with susceptibility to Crohn's disease in the German population

OBJECTIVES

We analyzed ATG16L1, a recently identified Crohn's disease (CD) susceptibility gene, in a large cohort with inflammatory bowel disease (IBD) including potential interactions with other IBD genes as well as factors regulating its gene expression.

METHODS

Genomic DNA from 2,890 Caucasians including 768 patients with CD, 507 patients with ulcerative colitis (UC), and 1,615 healthy controls was analyzed for 9 different ATG16L1 single nucleotide polymorphisms (SNPs). Genotyping included CARD15/NOD2 variants p.Arg702Trp, p.Gly908Arg, and p.Leu1007fsX1008 and polymorphisms in SLC22A4/OCTN1 (1672 C-->T) and SLC22A5/OCTN2 (-207 G-->C) as well as 10 CD-associated IL23R variants. The transcriptional regulation of ATG16L1 was studied in intestinal epithelial cells following stimulation with Toll-like receptor (TLR) ligands and proinflammatory cytokines and in a murine ileitis model and CD biopsies.

RESULTS

All nine ATG16L1 gene variants analyzed displayed highly significant associations with CD demonstrating a CD-protective effect for the minor allele. The strongest associations were found for rs2241879 and the coding SNP rs2241880 (T300A); P= 3.6 x 10(-6) and 3.7 x 10(-6), respectively (OR 0.74, 95% CI 0.65-0.84 for both variants). The genotype-phenotype analysis revealed no significant associations. In UC, only rs6431660 was weakly disease-associated. There was no evidence for epistasis between the ATG16L1 gene and other susceptibility genes (IL23R, CARD15, SLC22A4/5). ATG16L1 mRNA expression was not upregulated in CD and murine ileitis, and was less than threefold increased in cells stimulated with proinflammatory cytokines and TLR ligands.

CONCLUSION

ATG16L1 is a CD susceptibility gene without epistatic interaction with other CD susceptibility genes and is not upregulated in intestinal inflammation.

The role of the selenoprotein S (SELS) gene -105G>A promoter polymorphism in inflammatory bowel disease and regulation of SELS gene expression in intestinal inflammation

Recently, a -105G>A promoter polymorphism coding for selenoprotein S (SELS) has been shown to increase proinflammatory cytokine expression. We, therefore, analyzed SELS expression and potential phenotypic consequences of the -105G>A polymorphism in patients with inflammatory bowel disease (IBD). SELS mRNA was measured by quantitative polymerase chain reaction (PCR) in intestinal epithelial cells (IEC) after stimulation with proinflammatory cytokines and in human colonic biopsies of IBD patients as well as in murine models of ileitis and murine cytomegalovirus (MCMV) colitis. Genomic DNA from 563 individuals (Crohn's disease: n = 205; ulcerative colitis: n = 154; controls: n = 204) was analyzed for the presence of the SELS-105G>A polymorphism and the three nucleotide-binding oligomerization domain-containing protein 2 (NOD2)/caspase recruitment domain-containing protein 15 (CARD15) variants p.Arg702Trp, p.Gly908Arg and p.Leu1007fsX1008. SELS mRNA expression was increased in IEC after stimulation with proinflammatory cytokines, while its expression was not significantly altered in murine ileitis and MCMV colitis and in inflamed ileal and colonic lesions in IBD patients compared with normal controls. The SELS-105G>A polymorphism was observed with similar frequencies in IBD patients and controls and was not associated with a certain disease phenotype or serum tumor necrosis factor alpha (TNF-alpha) levels in these patients. Medium serum TNF-alpha was 1.27 pg/ml in IBD patients, while none of the controls had TNF-alpha concentrations above the detection threshold (P < 0.0001). SELS mRNA expression is upregulated by proinflammatory cytokines in IECs but the SELS-105G>A polymorphism is not associated with IBD susceptibility and does not contribute to a certain disease phenotype or increased TNF-alpha levels in IBD patients.

rs1004819 is the main disease-associated IL23R variant in German Crohn's disease patients: combined analysis of IL23R, CARD15, and OCTN1/2 variants

Background

The IL23R gene has been identified as a susceptibility gene for inflammatory bowel disease (IBD) in the North American population. The aim of our study was to test this association in a large German IBD cohort and to elucidate potential interactions with other IBD genes as well as phenotypic consequences of IL23R variants.

Methods

Genomic DNA from 2670 Caucasian individuals including 833 patients with Crohn's disease (CD), 456 patients with ulcerative colitis (UC), and 1381 healthy unrelated controls was analyzed for 10 IL23R SNPs. Genotyping included the NOD2 variants p.Arg702Trp, p.Gly908Arg, and p.Leu1007fsX1008 and polymorphisms in SLC22A4/OCTN1 (1672 C→T) and SLC22A5/OCTN2 (–207 G→C).

Results

All IL23R gene variants analyzed displayed highly significant associations with CD. The strongest association was found for the SNP rs1004819 [P = 1.92×10⁻¹¹; OR 1.56; 95 % CI (1.37–1.78)]. 93.2% of the rs1004819 TT homozygous carriers as compared to 78% of CC wildtype carriers had ileal involvement [P = 0.004; OR 4.24; CI (1.46–12.34)]. The coding SNP rs11209026 (p.Arg381Gln) was protective for CD [P = 8.04×10⁻⁸; OR 0.43; CI (0.31–0.59)]. Similar, but weaker associations were found in UC. There was no evidence for epistasis between the IL23R gene and the CD susceptibility genes CARD15 and SLC22A4/5.

Conclusion

IL23R is an IBD susceptibility gene, but has no epistatic interaction with CARD15 and SLC22A4/5. rs1004819 is the major IL23R variant associated with CD in the German population, while the p.Arg381Gln IL23R variant is a protective marker for CD and UC.

Adalimumab in patients with Crohn's disease--safety and efficacy in an open-label single centre study

AIM

To evaluate the efficacy and safety of adalimumab, a human antitumour necrosis factor-alpha antibody, in induction and maintenance of remission in patients with Crohn's disease either refractory or intolerant to infliximab in a single centre cohort.

METHODS

Sixteen Crohn's disease patients received 160 mg adalimumab subcutaneously in week 0, followed by 80 mg every other week. Clinical response was assessed based on Crohn's disease activity index and laboratory parameters (leukocyte count, C-reactive protein). In all patients genotyping for CARD15 variants and the +1059G/C polymorphism in the C-reactive protein gene was performed.

RESULTS

In 10 of 16 patients (63%) treated with adalimumab, remission (CDAI score <150) was induced for at least 8 weeks independent of CARD15 or +1059G/C CRP status. In six of these 10 patients ongoing remission is observed now for more than 24 weeks. Adalimumab significantly decreased C-reactive protein serum levels and Crohn's disease activity index. There was one serious complication (fungal pneumonia). Six patients intermittently developed minor dermatological problems resolving after topical therapy. Otherwise, treatment was generally well tolerated.

CONCLUSION

Adalimumab can induce and maintain remission in patients with moderate to severe Crohn's disease intolerant or refractory to infliximab. Further experience from larger cohorts is required to evaluate dose regimen and safety profiles in Crohn's disease therapy.

Macrophage migration inhibitory factor (MIF) -173G/C promoter polymorphism influences upper gastrointestinal tract involvement and disease activity in patients with Crohn's disease

BACKGROUND

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine with increased expression in inflammatory bowel disease. The aim of the study was to analyze the role of the MIF -173G/C single nucleotide polymorphism in Crohn's disease (CD).

METHODS

Using restriction fragment length polymorphism analysis, genomic DNA of 198 patients with CD and 159 unrelated controls was analyzed for the -173G/C SNP in the MIF promoter region. Colonic MIF mRNA expression was measured by quantitative polymerase chain reaction (PCR), serum MIF levels by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Thirty-six of the 146 G/G wildtype carriers (24.7%) but only 3 of the 45 G/C heterozygotes (6.7%) and only 1 of the C/C homozygotes (14.3%) were diagnosed with upper gastrointestinal tract involvement (P = 0.009, odds ratio [OR] = 0.22, 95% confidence interval [CI], 0.06-0.75 for wildtype versus hetero- and homozygous carriers). This result was confirmed in a second prospective study, in which all patients diagnosed with upper gastrointestinal involvement (n = 13) were G/G wildtype carriers (P = 0.01 versus controls). All patients (n = 12; 100%) with a Crohn's disease activity index (CDAI) > 300 were G/G wildtype carriers compared to only 65.6% wildtype carriers in the group with a CDAI < 150 (P = 0.016). MIF is expressed in the colonic mucosa of CD patients and intestinal epithelial cells but its mRNA expression does not correlate with the degree of inflammation and is not upregulated by proinflammatory cytokines. In CD, MIF serum levels are not influenced by the MIF -173G/C polymorphism.

CONCLUSIONS

The MIF -173G/C polymorphism appears to be a factor contributing to a particular CD phenotype characterized by protection against upper gastrointestinal tract involvement and severe disease activity.

Homozygosity for the CARD15 frameshift mutation 1007fs is predictive of early onset of Crohn's disease with ileal stenosis, entero-enteral fistulas, and frequent need for surgical intervention with high risk of re-stenosis

OBJECTIVE

The identification of CARD15 as a susceptibility gene for Crohn's disease (CD) offers new possibilities for patient classification and risk assessment. The purpose of this study was to carry out a CARD15 sequence analysis in a large single-center IBD cohort and to investigate the impact of different genotypes on disease phenotypes.

MATERIAL AND METHODS

A total of 445 unrelated patients with IBD (68.1% CD, 28.5% ulcerative colitis (UC), 3.4% indeterminate colitis (IC)) were included in the study. Clinical data were recorded by detailed questionnaire and analysis of the charts. CARD15 variants (R702W, G908R, 1007fs (frameshift)) were identified by DNA sequence analysis.

RESULTS

CARD15 variants were found in 142 inflammatory bowel disease (IBD) patients (31.9%) including 120 CD patients (39.6%). In CD, the presence of two CARD15 variants was associated with ileal disease (p=0.008 versus wild-type (wt); OR 4.04; 95% CI 1.36-11.96) and a fibrostenotic phenotype (p=0.002 versus wt; OR 5.47; 95% CI 1.61-18.58). Subgroup analysis of 19 patients (4.3%) homozygous for the CARD15 variant 1007fs (3020ins C) revealed an association with onset of CD at an early age (p=0.014 versus wt), ileal involvement (p=0.001), and intestinal stenoses in all patients (p=0.001) frequently requiring surgery (73.7%; p=0.093). Of these patients 78.6% developed re-stenoses after surgical resection; 52.6% of the homozygotes were diagnosed as having entero-enteral fistulas.

CONCLUSIONS

Patients homozygous for the 1007fs mutation had an early disease onset with long-segment ileal stenoses and entero-enteral fistulas. They frequently needed surgical intervention and had a high risk of re-stenosis. Genotyping therefore appears to be an important diagnostic tool in identifying severely affected patients requiring individualized treatment strategies at an early stage of the disease.

Predictive value of the CARD15 variant 1007fs for the diagnosis of intestinal stenoses and the need for surgery in Crohn's disease in clinical practice: results of a prospective study

BACKGROUND AND AIM

The diagnostic and therapeutic relevance of CARD15 genotyping in Crohn's disease (CD) for daily clinical practice has not been investigated so far. We therefore analyzed whether CARD15 variants are independent predictive factors for small bowel stenosis in CD evaluated by magnetic resonance enteroclysis (MRE). On the basis of these findings, the potential implications for patient management were investigated.

METHODS

Eighty CD patients with clinical symptoms suggestive of small bowel stenosis were included. All patients were genotyped for the CARD15 variants c.2104C > T (p.R702W), c.2722G > C (p.G908R), and c.3019_3020insC (p.Leu1007fsX1008) and examined by MRE of the small bowel.

RESULTS

CARD15 variants were found in 40 (50%) patients. MRE identified 31 (38%) patients with small bowel stenoses. Twenty-five of the 40 (62%) patients with at least one CARD15 variant were diagnosed of intestinal stenosis by MRE (odds ratio [OR] = 9.44; confidence interval [CI] 3.21-27.77; P = 0.00028, Bonferroni corrected). Particularly, the presence of the 1007fs variant was associated with an increased risk of an intestinal stenosis (OR = 12.00, CI 3.47-41.54, P = 0.00042, Bonferroni corrected). Twenty-one of 31 (68%) patients with stenoses required surgical intervention, with 13 of these 21 (62%) patients carrying the 1007fs variant.

CONCLUSION

In the largest prospective study analyzing the diagnostic value of CARD15 variants in CD patients performed so far, we identified the 1007fs variant as strong predictor for intestinal stenoses with need for surgery in CD patients. Genotyping could therefore be an important diagnostic tool in clinical practice for identifying high-risk patients with specific diagnostic and therapeutic needs. Moreover, MRE is an excellent technique for diagnosing small bowel stenoses.

The +1059G/C polymorphism in the C-reactive protein (CRP) gene is associated with involvement of the terminal ileum and decreased serum CRP levels in patients with Crohn's disease

BACKGROUND

Serum C-reactive protein (CRP) levels influence the response to anti-tumour necrosis factor (TNF) therapies.

AIM

To analyse the influence of the +1059G/C CRP polymorphism on CRP serum levels and disease susceptibility in patients with Crohn's disease (CD).

METHODS

Using restriction fragment length polymorphism (RFLP) analysis, genomic DNA from 241 CD patients and 199 unrelated controls was analysed for the +1059G/C substitution in the CRP gene and the common caspase-activation recruitment domain 15 (CARD15) variants.

RESULTS

Homozygous C/C carriers were detected only among CD patients (P = 0.066). Patients with ileal involvement (L1 and L3 phenotype) were found in only 58.4% of patients with the wildtype G/G genotype but in 88.2% of the heterozygous G/C carriers (OR 5.26; 95% CI 1.19-23.92) and four of the five C/C homozygous carriers (80%; OR 4.55; 95% CI 1.64-16.67; P = 0.008 for hetero- and homozygous carriers vs. wildtype) which was independent of the presence of CARD15 variants. Increased CD activity was associated with increased CRP serum levels (P < 0.005). For Crohn's disease activity index (CDAI) < 150, C/C homozygosity for the +1059 G/C polymorphism was associated with significantly lower CRP serum levels (P < 0.01).

CONCLUSIONS

The C allele of the CRP +1059G/C polymorphism is associated with decreased serum CRP levels and increased likelihood of disease involvement of the terminal ileum in CD patients.

Eight novel CARD15 variants detected by DNA sequence analysis of the CARD15 gene in 111 patients with inflammatory bowel disease

We performed a limited DNA sequence analysis of the CARD15 gene in 89 patients with Crohn's disease (CD), 19 patients with ulcerative colitis (UC), and three patients with indeterminate colitis (IC), who were heterozygous carriers of one of the common CARD15 mutations [c.2104C>T (p.R702W), c.2722G>C (p.G908R), or c.3019_3020insC (p.Leu1007fsX1008)], the c.2462+10A>C variant, or of a new amino acid substitution in the 3'-end of exon 4. CARD15 exons 4, 5, 6, 8, and 11 were amplified by PCR and completely sequenced, thereby theoretically covering 73.9% of the described CARD15 variants and 96.6% of the mutated alleles. Using this approach, eight novel amino acid substitutions [c.1171C>T (p.R391C), c.1387C>G (p.P463A), c.2138G>A (p.R713H), c.2278C>T (p.R760C), c.2368C>T (p.R790W), c.2371C>T (p.R791W), c.2475C>G (p.N825K), and c.2546C>T (p.A849V)] were detected in six CD and two IC patients, and one UC patient. A severe disease phenotype was observed especially in patients who are compound-heterozygous for a common and a novel CARD15 mutation.

Increased expression of the chemokine fractalkine in Crohn's disease and association of the fractalkine receptor T280M polymorphism with a fibrostenosing disease Phenotype

BACKGROUND

The fractalkine receptor CX3CR1 has been shown to be involved in inflammation and immune response. Recently, two polymorphisms of CX3CR1 (V249I and T280M) were reported.

AIMS

Our aim was to analyze fractalkine expression and the role of CX3CR1 polymorphisms in Crohn's disease (CD).

METHODS

We determined fractalkine mRNA expression in the intestinal epithelial cell (IEC) line SW480 after stimulation with proinflammatory cytokines as well as in inflamed (n = 14) and noninflamed (n = 14) CD lesions by quantitative PCR. By restriction fragment length polymorphism analysis, genomic DNA from 206 patients with CD and 211 unrelated controls was analyzed for the two single nucleotide polymorphisms in the CX3CR1 gene, which result in the V249I and T280M substitutions.

RESULTS

All proinflammatory stimuli (TNF-alpha, IL-1beta, LPS) significantly increased fractalkine mRNA expression in IEC. There was also a significant increase in fractalkine mRNA expression in inflamed lesions of CD patients when compared to noninflamed colonic mucosa (p = 0.02). Intestinal fractalkine mRNA levels correlated highly with IL-8 mRNA expression levels (r = 0.931). However, there was no difference in the V249I and T280M genotype frequencies between CD patients and the control group. In the CD group, 33.0% were heterozygous and 8.3% homozygous for the V249I polymorphism, while 23.3% were heterozygous and 4.4% homozygous for the T280M polymorphism. All T280M homozygotes were diagnosed of intestinal stenosis (p = 0.03 vs wildtype and heterozygous carriers) and had significantly more often ileocolonic involvement more often than patients with wildtype and heterozygous genotypes (p = 0.01). These associations were independent of the CARD15 genotype status.

CONCLUSIONS

The expression of the chemokine fractalkine is upregulated by proinflammatory cytokines and enhanced in inflamed CD lesions. The CX3CR1 T280M polymorphism appears to influence CD phenotype and localization.

The role of Toll-like receptor 4 Asp299Gly and Thr399Ile polymorphisms and CARD15/NOD2 mutations in the susceptibility and phenotype of Crohn's disease

BACKGROUND

We investigated the influence of 2 common Toll-like receptor 4 (TLR4) polymorphisms on susceptibility and disease characteristics of Crohn's disease (CD).

METHODS

Genomic DNA from 204 patients with CD and 199 unrelated controls was analyzed for the presence of 2 single nucleotide polymorphisms in the TLR4 gene, resulting in the amino acid substitutions Asp299Gly and Thr399Ile. In addition, the carrier status for the 3 common CD-associated CARD15/NOD2 gene mutations, Arg702Trp, Gly908Arg, and 1007fs, was determined. The frequency of the different genotypes was compared, and a detailed genotype-phenotype correlation was performed.

RESULTS

An almost 2-fold increase in the frequency of the TLR4 Asp299Gly phenotype was observed in patients with CD (14.2%) compared with healthy controls (7.5%, P = 0.038, odds ratio = 2.03). The prevalence of a stricturing phenotype was increased in patients heterozygous for 1 of the TLR4 polymorphisms studied (Asp299Gly, 34.5%; Thr399Ile, 36.7%) compared with patients with wild-type TLR4 (17.1% and 16.7%; P = 0.04 and 0.02, respectively). The presence of the Asp299Gly polymorphism in the absence of CARD15/NOD2 mutations was a particularly strong predictor of the stricturing disease phenotype that was present in 47.4% of the patients with Asp299Gly+/NOD2- compared with 10.1% of the patients with the Asp299Gly-/NOD2+ status (P = 0.0009; P = 0.0004 for Thr399Ile+/NOD2- versus Thr399Ile-/NOD2+). In contrast, there was a trend toward a higher prevalence of the penetrating phenotype in the TLR4-/NOD2+ group (71.6%) compared with the TLR4+/NOD2- group (47.4%, P = 0.059).

CONCLUSIONS

The TLR4 Asp299Gly polymorphism is a risk factor for CD. TLR4 and CARD15/NOD2 mutations may contribute to distinct disease phenotypes.