Georgia Hume

TNFα and IL10 SNPs act together to predict disease behaviour in Crohn’s disease

Background: The cytokines tumour necrosis factor (TNF)α and interleukin (IL)10 have been implicated in the pathogenesis of Crohn’s disease (CD), with increased concentrations reported in patients with active disease. However, limited data exist on their effects on disease phenotype in the same population. Certain single nucleotide polymorphisms (SNPs) within the promoter region of the IL10 (-1082G/A, -592C/A) and TNFα (-308G/A, -857C/T) genes have been associated with altered levels of circulating IL10 and TNFα. Methods: We conducted an Australian based case–control study (304 CD patients; 231 healthy controls) of these four SNPs. Further investigation of two SNPs was conducted using a logistic regression analysis. Results: We identified a possible association of both IL10 SNPs and TNFα-857 with CD. Further investigation of a relationship with disease severity showed a significant association of higher producing IL10-1082G and TNFα-857C alleles with stricturing behaviour, which was strongest when these alleles were combined and persisted after multivariate analysis (p = 0.007; odds ratio (OR) 2.37, 95% CI 1.26 to 4.43). In addition, the TNFα-857CC genotype was independently associated with familial CD (p = 0.03; OR 3.12; 95% CI 1.15 to 8.46). Conclusion: These two SNPs may help to predict disease behaviour in CD patients, which may be clinically useful in shaping treatment of the disease at an earlier stage.

Novel NOD2 haplotype strengthens the association between TLR4 Asp299gly and Crohn's disease in an Australian population

Background: The first major Crohns disease (CD) susceptibility gene, NOD2, implicates the innate intestinal immune system and other pattern recognition receptors in the pathogenesis of this chronic, debilitating disorder. These include the Toll‐like receptors, specifically TLR4 and TLR5. A variant in the TLR4 gene (A299G) has demonstrated variable association with CD. We aimed to investigate the relationship between TLR4 A299G and TLR5 N392ST, and an Australian inflammatory bowel disease cohort, and to explore the strength of association between TLR4 A299G and CD using global meta‐analysis. Methods: Cases (CD = 619, ulcerative colitis = 300) and controls (n = 360) were genotyped for TLR4 A299G, TLR5 N392ST, and the 4 major NOD2 mutations. Data were interrogated for case‐control analysis prior to and after stratification by NOD2 genotype. Genotype–phenotype relationships were also sought. Meta‐analysis was conducted via RevMan. Results: The TLR4 A299G variant allele showed a significant association with CD compared to controls (P = 0.04) and a novel NOD2 haplotype was identified which strengthened this (P = 0.003). Furthermore, we identified that TLR4 A299G was associated with CD limited to the colon (P = 0.02). In the presence of the novel NOD2 haplotype, TLR4 A299G was more strongly associated with colonic disease (P < 0.001) and nonstricturing disease (P = 0.009). A meta‐analysis of 11 CD cohorts identified a 1.5‐fold increase in risk for the variant TLR4 A299G allele (P < 0.00001). Conclusions: TLR 4 A299G appears to be a significant risk factor for CD, in particular colonic, nonstricturing disease. Furthermore, we identified a novel NOD2 haplotype that strengthens the relationship between TLR4 A299G and these phenotypes.

Angiotensinogen and transforming growth factor beta1: novel genes in the pathogenesis of Crohn's disease.

Background: Angiotensin peptides may act locally as cytokines in several organ systems with elevated mucosal levels present in Crohn’s disease. A variant in the angiotensinogen gene promoter results in increased peptide production, while transforming growth factor β1 (TGFβ1) codon 25 variants demonstrate variable peptide production, predisposing to fibrosis in several organs. Aims: Conduct an Australian-based analysis of the angiotensinogen-6 variant in two independent inflammatory bowel disease (IBD) cohorts, and examine the role of angiotensinogen-6 and TGFβ1 codon 25 variants in shaping Crohn’s disease phenotype. Methods: IBD Patients (Crohn’s disease = 347, ulcerative colitis = 147) and CD families (n = 148) from two cohorts, together with 185 healthy controls were genotyped for angiotensinogen-6. Genotype-phenotype analyses were performed for both angiotensinogen-6 and TGFβ1 codon 25. Results: Angiotensinogen-6 AA genotype was significantly associated with Crohns disease (p = 0.007, OR = 2.38, CI = 1.32–4.32) in cohort 1, but not in the smaller cohort 2 (p = 0.19). The association remained significant when the two cohorts were combined (p = 0.008), and in a TDT family analysis (p = 0.03). TGF 1 codon 25 was associated with stricturing Crohn’s disease (p = 0.01, OR = 2.63, CI = 1.16–5.88) and a shorter time to intestinal resection (p = 0.06). Conclusions: The association of the angiotensinogen-6 variant with Crohn’s disease supports a potential role for angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists in disease treatment.

Altered Expression of Angiotensinogen and Mediators of Angiogenesis in Ileal Crohn's Disease.

BACKGROUND AND AIMS Angiotensin II (AII) is a powerful splanchnic vasoconstrictor with pro-inflammatory and pro-fibrotic properties. Angiotensin converting enzyme (ACE) inhibitors and AII Receptor Antagonists (ARBs) are therapeutic in animal models of colitis. The aim of this case-control study is to determine the expression of angiotensinogen and related genes in human ileal Crohns disease. METHODS Using quantitative real-time polymerase chain reaction (RT-PCR), we measured mRNA expression levels of angiotensinogen (AGT), hypoxia inducible factor (HIF)1α and melanoma cell adhesion molecule (MCAM; CD146) in 101 human samples (69 biopsy, 12 resection) from affected ileum (inflamed CD cases, n=36) and unaffected ileum (non-inflamed CD cases, n=45 and controls, n=20). Immunohistochemistry for angiotensinogen was also performed. The study was of case-control design in a tertiary care setting. RESULTS Ileal expression of AGT was lower in CD cases compared to controls (p<0.0001), in inflamed CD samples (p=0.017) and current smokers (p=0.02). HIF1α expression was lower in non-inflamed CD biopsy samples than controls (p=0.006). The presence of disease-associated NOD2 variants was associated with increased expression of markers of angiogenesis (HIF1α p=0.009; MCAM p=0.007) in inflamed CD samples. Angiotensinogen immunohistochemical staining supported the quantitative RT-PCR expression findings. CONCLUSIONS Angiotensinogen expression is down regulated in human ileal CD, particularly in the presence of inflammation and current cigarette smoking, implicating the mesenteric vasculature and mucosal hypoxia as co-factors in ileal CD pathogenesis. A novel reduction in HIF1α expression in non-inflamed ileal mucosa in CD patients was also demonstrated.

The Use of Acetic Acid in Magnification Colonoscopy

The Use of Acetic Acid in Magnification Colonoscopy Kazutomo Togashi, David G. Hewett, David A. Whitaker, Georgia E. Hume, Leo Francis, Mark N. Appleyard Background: Staining dyes can provide a clear image in magnification colonoscopy, but not instantly. Indigocarmine (IC) shows contrast effect instantly, but this effect is not as reliable as the staining dyes. Acetic acid (AA) is cheap, easily available and safe. AA has been used in the evaluation of cervical and oesophageal mucosa, but its use has not been evaluated in magnification colonoscopy. The aim of this study was to evaluate the role of AA dye spray during magnification colonoscopy alone and in combination with IC dye. Methods: In one institution, 46 patients (F22, M24; age 56617) entered into a prospective study of magnification colonoscopy, performed by a single endoscopist. The 46 consecutive patients were divided alternately into 2 groups; A (n=23) andB (n=23). InGroup A, 1.5%AAwas initially sprayed on to all detected lesions, followed by spray with 0.2% IC. In Group B, the order was reversed, with IC preceding AA. Pit pattern image was assessed in real time after the spraying of each consecutive dye. Pit patterns were evaluated based upon Kudo’s classification. The time required to obtain a clear image after the first dye spray wasmeasured. The effect of the second dye was evaluated based upon whether the pit pattern image following additional dye spray was clearer than that after the first dye alone. Results: 37 adenomas (AD), 36 hyperplastic polyps (HP), 5 normalmucosa, 4 inflammatory polyps and 1 serrated adenoma were detected. The 73 lesions comprised of AD and HP alone were subjected to further analysis. In group A, 20 AD and 23 HP were detected, and accuracies after AA spray were 95% with AD and 96% with HP. After subsequent IC spray, 37% showed enhanced images, and accuracies increased to 100% in AD and 97% in HP. In group B, 17 AD and 13 HP were detected, and accuracies after IC spray were 76% with AD and 92% with HP. After subsequent AA spray, images were enhanced in 70%with increases in accuracy to 94% in AD and 100% in HP. In both groups, the mean time required to obtain an initial clear image was 14 seconds. Conclusion: The use of AA spray instantly improves pit pattern image during magnification chromo-colonoscopy and improves the accuracy of histological prediction of colorectal polyps. This method could be easily applied to routine magnification colonoscopy. **267 Prevalence and Characteristics of Flat and Depressed Colorectal Neoplasms in a Western Population: A Prospective Study by a Japanese Trained Endoscopist Noriko Suzuki, Nicola C. Palmer, Brian P. Saunders Background: Flat and depressed colorectal neoplasms have been widely investigated in Japan and recently inWestern countries with incidence rate of 6.8%48.5%. This wide variation reflects differences in population characteristics or colonoscopic technique. The aim of this study was to determine the prevalence of flat neoplasms in a UK population by a colonoscopist trained in Japan. Methods: A prospective analysis of 1000 consecutive colonoscopies was performed. Macroscopically the lesions were classified according to the classification described by Japanese Society for Cancer of the Colon and Rectum and histological diagnosis was made based on WHO system. Result: Total colonoscopy (adjusted) was achieved in 98% of patients. Indications for colonoscopy were: neoplasia surveillance (211), change in bowel habit (179), bleeding (160), assessment of IBD (141), family history of colorectal neoplasms (106), anaemia (86), and others (117). In total 1075 polyps were found in 412 patients, which includes 25 cases of advanced cancer. 758 polyps were histologically proven to be neoplastic. Of these, 617 were classified as polypoid (81%) and 141 flat (IIa, IIb, IIc)(19%). A higher incidence of advanced pathology (severe dysplasia or Dukes’A adenocarcinoma) was observed in flat and depressed neoplasms (0% in IIa, 14% in IIb,IIc) than in polypoid ones (2%). Conclusion: A Japanese trained endoscopist found flat neoplasms represented 19 % of all adenomas (flat/ depressed 3% in a western population. Flat elevated (IIa) and polypoid lesions appeared to have similar characteristics, while flat (IIb) or depressed lesions (IIc) contain more advanced pathology. Flat and depressed neoplasms are rare finding but exist in a Western population.

The need for better preventative strategies for inflammatory bowel disease patients at risk of herpes zoster virus

Immunosuppressed inflammatory bowel disease (IBD) patients have an increased risk of herpes zoster virus (HZV) infection. The existing live‐attenuated HZV vaccine is contraindicated in some of these patients and can only be used with caution in others.