Inducible and endothelial nitric oxide synthase genes polymorphism in inflammatory bowel disease

Polymorphisms in oxidative pathway related genes and susceptibility to inflammatory bowel disease

AIM

To investigate whether common variants in the oxidative pathway genes influence inflammatory bowel disease (IBD) risk among Moroccan patients.

METHODS

The distribution of (TAAA)n_rs12720460 and (CCTTT)n _rs3833912 NOS2A microsatellite repeats, HIF-1A_rs11549467 and NFKB1-94ins/delATTG_rs28362491 was analyzed in 507 subjects grouped in 199 IBD and 308 healthy controls. Genotyping was performed with polymerase chain reaction-fluorescent method and the TaqMan^® allelic discrimination technology.

RESULTS

The allele and genotype frequencies of HIF1A_ rs11549467, NFKB1_rs28362491 and NOS2A_ (TAAA)n did not differ significantly between patients and controls. Analysis of NOS2A_ (CCTTT)n markers evidenced differences between patients and healthy controls. A preferential presence of the (CCTTT)8 (P = 0.02; OR = 1.71, 95%CI: 1.07-2.74), (CCTTT)14 (P = 0.02; OR = 1.71, 95%CI: 1.06-2.76) alleles in IBD, (CCTTT)8 (P = 0.008; OR = 1.95, 95%CI: 1.17-3.23) in CD and (CCTTT)7 (P = 0.009; OR = 7.61, 95%CI: 1.25-46.08), (CCTTT)11 (P = 0.05; OR = 0.51, 95%CI: 0.25-1.01), (CCTTT)14 (P = 0.02; OR = 2.05, 95%CI: 1.07-3.94), (CCTTT)15 (P = 0.01; OR = 2.25, 95%CI: 1.16-4.35) repeats in UC patients indicated its possible association with higher disease risk which need to be confirmed in a larger sample size.

CONCLUSION

Our results suggest that the NOS2A_ (CCTTT)n gene variations may influence IBD susceptibility in the Moroccan population.

Advances in studies on relation between inflammatory bowel disease and immunity

Inflammatory bowel disease is a chronic inflammatory disease of the gastrointestinal tract. Its main clinical manifestations are abdominal pain and diarrhea. Its etiology is complicated. Immune system is very important. Following factors, such as intestinal environment, immune cells, human leukocyte antigens, antibodies, anti- laminaribioside antibody, anti-chitobioside antibody IgA, cytokines, cell adhesion molecules, NO and NF-κB, play a key role in the pathogenesis of inflammatory bowel disease. Inflammatory bowel disease is related to all these factors. This paper reviews the possible role of these immune factors in the pathogenesis of inflammatory bowel disease.

Association of a CXCL9 polymorphism with pediatric Crohn’s disease

Genetic and environmental factors contribute to the etiopathogenesis of Crohn's disease (CD) and ulcerative colitis (UC). To identify new susceptibility genes, we determined the mRNA expression level of 88 genes from different biological contexts on colonic biopsies of CD and UC patients. We show that CXCL9 was overexpressed in colonic tissue of 3/5 CD and 3/3 UC patients compared to healthy controls. SNP genotyping for the 77147452G-->A polymorphism of the CXCL9 gene on 114 pediatric IBD patients and 120 ethnically matched unaffected adults detected a minor allele frequency of 20.3% in CD patients compared to 31.3% in controls (p=0.016). Strikingly, children with homozygosity for the wild-type allele had a significant earlier onset of CD than heterozygous individuals (11.1 versus 13.8 years). This is the first report of inverse association of the CXCL9 77147452G-->A polymorphism with pediatric CD. Our data may contribute to a better understanding of the pathophysiology underlying CD.

Influence of the inducible nitric oxide synthase gene (NOS2A) on inflammatory bowel disease susceptibility

The great amount of nitric oxide (NO) produced by the inducible isoform of NO synthase (iNOS) exerts deleterious effects, and iNOS expression is raised in the colonic mucosa of inflammatory bowel disease (IBD) patients. This is the first association analysis of polymorphisms within the NOS2A extended gene with IBD susceptibility. We analyzed 336 patients of Crohn's disease (CD), 355 of ulcerative colitis (UC), and 536 healthy controls from a Spanish population. We tested a (CCTTT)n microsatellite, a (-/TAAA) insertion, and two single nucleotide polymorphisms (SNPs) flanking them (rs2779251 and rs2779248) in the NOS2A promoter, together with two SNPs in the coding region: one within exon 10, D385D (rs1137933), and another mapping to exon 16, S608L (rs2297518). Analysis of these markers evidenced differences among IBD patients and healthy controls. Allele (CCTTT) 13 is related to higher UC risk (p = 0.001; odds ratio [OR] [95% confidence interval, CI] = 1.64 [1.20-2.23]). Carriers of minor alleles of the two promoter SNPs analyzed showed an association with UC predisposition, and common allele homozygotes of the two exonic SNPs were more frequent among CD patients than among controls. Concordantly, one out of the three haplotypes carrying both exonic risk alleles was found to increase CD susceptibility (p = 0.007; OR [95%CI] = 1.74 [1.13-2.67]). Therefore, the NOS2A gene seems to be involved in IBD aetiology.

Changes in pulmonary function in patients with ulcerative colitis

OBJECTIVES

Information on the occurrence and frequency of pulmonary involvement in patients with ulcerative colitis (UC) is inconsistent. Some authors reported pulmonary impairment with UC by standard pulmonary function tests (PFTs) and documented a reduced diffusing capacity for carbon monoxide (DLCO) especially in patients with active disease, whereas others could not detect differences in routine PFTs between UC patients and controls.

AIM

The aim of this prospective study was to determine the frequency and type of pulmonary dysfunction in patients with UC with respect to disease activity. Furthermore, to evaluate the influence of smoking, nutritional status, sputum cytology and sulphasalazine therapy on PFT parameters.

PATIENTS AND METHODS

Twenty-six patients with UC (20 with active disease, 6 inactive) and 16 age and sex matched healthy controls were investigated with respect to the following pulmonary function tests, forced vital capacity (FVC), forced expiratory volume in the 1s (FEV(1)%) and their ratio (FEV(1)/FVC) and forced expiratory flow 25-75% (FEF25-75%) as well as oxygen saturation. For UC patients, colonoscopy and biopsy were done. Disease activity was assessed by Truelove index for UC. Induced sputum was sampled for cytology. Smoking habit, body mass index (BMI) and medications were recorded.

RESULTS

Fifteen out of 26 patients with UC (57.6%) exhibited at least one pathological pulmonary function test (<80% of predicted value). Small airway obstruction was reported in the 15 patients, restrictive dysfunction in 30.7% and obstructive dysfunction in 11.5%. The impairment of PFTs was significant and more pronounced in patients with active disease, FVC (-14% of predicted), FEV(1) (-9% of predicted) and FEF25-75% (-32% of predicted), P<0.01, 0.05 and 0.01, respectively. There was no significant influence of smoking and medications on PFTs.

CONCLUSIONS

UC patients show significantly decreased lung function tests in comparison to healthy controls. The impairment in active disease exceeded that during the remission. Early recognition is important, as they can be strikingly steroid responsive.