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.

Internal fistulas in Crohn disease: magnetic resonance enteroclysis

Internal fistulas (IFs) and abscesses are the most common complications of Crohn disease (CD). To reliably diagnose and clearly distinguish inflammatory or fibrostenotic manifestations of CD from its complications is of paramount importance to appropriately guide therapeutic decisions. Magnetic resonance enteroclysis (MRE), a recently introduced technique for small bowel imaging, has proved a high efficacy in the depiction of luminal and extraluminal manifestations of CD and holds great promise as a powerful diagnostic tool in the comprehensive diagnostic workup of this disease. As of yet, the characteristic imaging appearance of IFs on MRE has not been described in detail. This article reviews the performance of conventional imaging techniques and the current potential of MRE in the depiction of IFs in CD. Typical imaging morphology and characteristic imaging findings of IFs on MRE are described in detail and a newly defined and highly indicative imaging finding, the "star-sign," is presented and discussed.

[A 67-year-old patient with somnolence and severe hyponatraemia]

A 67-year-old female patient with known depression was admitted to the intensive care unit with severe hyponatraemia (105 mmol/l) and somnolence caused by inadequate antidiuretic hormone secretion (SIADH) syndrome after starting therapy with the selective serotonin reuptake inhibitor (SSRI) Citalopram. This medication was stopped, and the hyponatraemia was carefully treated with fluid restriction and diuretics. Seven days later, the patient was discharged to a psychiatric ward with normal sodium levels and markedly improved vigilance. Given the increased use of SSRI for medical treatment of depression, the risk factors of this rare but potentially life-threatening complication and the diagnostic and therapeutic options are discussed.

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.

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.

6-Thioguanine treatment in inflammatory bowel disease: a critical appraisal by a European 6-TG working party

Recently, the suggestion to use 6-thioguanine (6-TG) as an alternative thiopurine in patients with inflammatory bowel disease (IBD) has been discarded due to reports about possible (hepato) toxicity. During meetings arranged in Vienna and Prague in 2004, European experts applying 6-TG further on in IBD patients presented data on safety and efficacy of 6-TG. After thorough evaluation of its risk-benefit ratio, the group consented that 6-TG may still be considered as a rescue drug in stringently defined indications in IBD, albeit restricted to a clinical research setting. As a potential indication for administering 6-TG, we delineated the requirement for maintenance therapy as well as intolerance and/or resistance to aminosalicylates, azathioprine, 6-mercaptopurine, methotrexate and infliximab. Furthermore, indications are preferred in which surgery is thought to be inappropriate. The standard 6-TG dosage should not exceed 25 mg daily. Routine laboratory controls are mandatory in short intervals. Liver biopsies should be performed after 6-12 months, three years and then three-yearly accompanied by gastroduodenoscopy, to monitor for potential hepatotoxicity, including nodular regenerative hyperplasia (NRH) and veno-occlusive disease (VOD). Treatment with 6-TG must be discontinued in case of overt or histologically proven hepatotoxicity.

Polymorphisms in the DLG5 and OCTN cation transporter genes in Crohn's disease

BACKGROUND AND AIMS

Recent data suggest identification of causal genetic variants for inflammatory bowel disease in the DLG5 gene and in the organic cation transporter (OCTN) cluster, both situated in previously described linkage regions.

PATIENTS AND METHODS

The polymorphisms in DLG5 (113 G-->A, 4136 C-->A, and DLG5_e26), SLC22A4 (1672 C-->T), and SLC22A5 (-207 G-->C) were assessed in 625 patients with Crohn's disease (CD), 363 patients with ulcerative colitis (UC), and 1012 healthy controls. Association with disease susceptibility, clinical phenotypes, and possible genetic interactions of these polymorphisms with disease associated CARD15/NOD2 mutations was analysed.

RESULTS

No significant association of DLG5 polymorphisms with CD or UC was observed. Homozygosity for the OCTN-TC haplotype was associated with an increased CD risk (OR = 1.65), which was even greater in the presence of CARD15 mutations. Genotype-phenotype analysis revealed that this association was particularly strong in patients with colonic disease. The TC haplotype was associated with non-fistulising non-fibrostenotic disease, an earlier age of disease onset, and reduced need for surgery.

CONCLUSION

Our observations argue against a role of DLG5 polymorphisms in the susceptibility for inflammatory bowel disease, whereas the OCTN polymorphisms are associated with CD. However, due to the comparable weak association observed herein, extended linkage disequilibrium analyses of these variants with the IBD5 haplotype tagged single nucleotide polymorphims might be advisable before definitive conclusions about their causative role in CD can be drawn.

Enhanced dendritic cell maturation by TNF-alpha or cytidine-phosphate-guanosine DNA drives T cell activation in vitro and therapeutic anti-tumor immune responses in vivo

Dendritic cells (DC) manipulated ex vivo can induce tumor immunity in experimental murine tumor models. To improve DC-based tumor vaccination, we studied whether DC maturation affects the T cell-activating potential in vitro and the induction of tumor immunity in vivo. Maturation of murine bone marrow-derived DC was induced by GM-CSF plus IL-4 alone or by further addition of TNF-alpha or a cytidine-phosphate-guanosine (CpG)-containing oligonucleotide (ODN-1826), which mimics the immunostimulatory effect of bacterial DNA. Flow cytometric analysis of costimulatory molecules and MHC class II showed that DC maturation was stimulated most by ODN-1826, whereas TNF-alpha had an intermediate effect. The extent of maturation correlated with the secretion of IL-12 and the induction of alloreactive T cell proliferation. In BALB/c mice, s.c. injection of colon carcinoma cells resulted in rapidly growing tumors. In this model, CpG-ODN-stimulated DC cocultured with irradiated tumor cells also induced prophylactic protection most effectively and were therapeutically effective when administered 3 days after tumor challenge. Thus, CpG-ODN-enhanced DC maturation may represent an efficient means to improve clinical tumor vaccination.