Leandra Mfuna Endam

Evidence of Association of Interleukin-1 Receptor-Like 1 Gene Polymorphisms with Chronic Rhinosinusitis:

Background Chronic rhinosinusitis (CRS) is a common complex respiratory disease, with a potential genetic component to its development. The protein encoded by the Interleukin-1 receptor-like 1 (IL1RL1) gene is an important effector molecule of T-helper type 2 responses and may potentially be involved in the persistent inflammatory process observed in CRS. We investigated whether certain polymorphisms in the IL1RL1 gene are differentially present in patients with surgery-unresponsive CRS and in control subjects. Methods DNA extracted from an existing population of 206 adult patients with surgery-unresponsive CRS and 196 postal-code-matched controls was used. A set of 15 tagging single nucleotide polymorphisms (SNPs) was selected from the HapMap data set and genotyped. DNA sequencing was performed in a subgroup of 15 CRS patients. Results Statistically significant allelic associations with CRS were noted for 5 SNPs (rs10204137, p = 0.04; rs10208293, p = 0.03; rs13431828, p = 0.008; rs2160203, p = 0.03, and rs4988957, p = 0.03). The analysis showed a consistent significant protective effect against CRS for all the SNPs, yielding an odds ratio (OR) ranging from 0.56 to 0.72. The loci rs13431828 showed the highest association with CRS (p = 0.008; OR = 0.56; 95% CI, 0.36–0.86). A subanalysis revealed that the observed associations were stronger among patients with more severe disease. Sequencing identified five additional known nonsynonymous coding SNPs in linkage disequilibrium with genotyped SNPs. Conclusion Pending replication of these results, this study suggests that polymorphisms within the IL1RL1 gene may be associated with CRS, conferring a protective effect, particularly among those with severe disease.

Genetic variations in taste receptors are associated with chronic rhinosinusitis: a replication study.

Recent evidence implicates polymorphisms of the bitter taste receptor TAS2R38 as defining characteristics in respiratory innate defense that may contribute to the complex genetic and environmental interactions predisposing to chronic rhinosinusitis (CRS). The purpose of this study was to (1) verify whether identified polymorphisms associated with respiratory infection in taste receptors replicate within our existing population of patients with CRS and (2) identify other taste receptors potentially associated with CRS.

Polymorphisms in the nitric oxide synthase 1 gene are associated with severe chronic rhinosinusitis.

Background Nitric oxide (NO), is a biological messenger molecule and a component of innate immunity, with important roles in the regulation of inflammation and in defense against bacterial biofilms. Polymorphisms in genes regulating NO production have the potential for a role in the development of chronic rhinosinusitis (CRS). The purpose of this study was to determine whether polymorphisms in genes regulating NO synthesis are associated with CRS. Methods An established population of 206 individuals with severe CRS and 196 postal code–matched controls was previously screened using a pooling genome-wide associations study to estimate allelic frequency. Genes regulating NO synthesis with a maximal probability of association were identified. High-probability single nucleotide polymorphisms SNPs from the NO synthase (NOS1) and its ligand NOS1 adaptor protein (NOS1AP) genes were retained for individual genotyping. PLINK software was used to determine association. Results Sixteen SNPs were genotyped successfully with a genotype distribution in agreement with Hardy-Weinberg equilibrium. Two SNPs for NOS1 (rs1483757 and rs9658281) were significantly associated with CRS, with a protective effect. The severe subphenotype showed stronger associations. Subgroup analysis for the presence of nasal polyps, origin, and gender did not influence strength of associations. Conclusion These data suggest that polymorphisms in the NOS1 gene may play a role in the susceptibility to develop CRS. Study findings apply to patients with severe CRS, unresponsive to surgery.

Polymorphisms in RYBP and AOAH Genes Are Associated with Chronic Rhinosinusitis in a Chinese Population: A Replication Study

Background The development of CRS is believed to be the result of combined interactions between the genetic background of the affected subject and environmental factors. Objectives To replicate and extend our recent findings from genetic association studies in chronic rhinosinusitis (CRS) performed in a Canadian Caucasian population in a Chinese population. Methods In a case-control replication study, DNA samples were obtained from CRS with (nu200a=u200a306; CRSwNP) and without (nu200a=u200a332; CRSsNP) nasal polyps, and controls (nu200a=u200a315) in a Chinese population. A total of forty-nine single nucleotide polymorphisms (SNPs) selected from previous identified SNPs associated with CRS in Canadian population, and SNPs from the CHB HapMap dataset were individually genotyped. Results We identified two SNPs respectively in RYBP (rs4532099, pu200a=u200a2.15E–06, ORu200a=u200a2.59) and AOAH (rs4504543, pu200a=u200a0.0001152, ORu200a=u200a0.58) significantly associated with whole CRS cohort. Subgroup analysis for the presence of nasal polyps (CRSwNP and CRSsNP) displayed significant association in CRSwNP cohorts regarding to one SNP in RYBP (Pu200a=u200a3.24E–006, ORu200a=u200a2.76). Evidence of association in the CRSsNP groups in terms of 2 SNPs (AOAH_rs4504543 and RYBP_rs4532099) was detected as well. Stratifying analysis by gender demonstrated that none of the selected SNPs were associated with CRSwNP as well as CRSsNP. Meanwhile 3 SNPs (IL1A_rs17561, Pu200a=u200a0.005778; IL1A_rs1800587, Pu200a=u200a0.009561; IRAK4_rs4251513, Pu200a=u200a0.03837) were associated with serum total IgE level. Conclusions These genes are biologically plausible, with roles in regulation of transcription (RYBP) and inflammatory response (AOAH). The present data suggests the potential common genetic basis in the development of CRS in Chinese and Caucasian population.

Polymorphisms in the SERPINA1 (Alpha-1-Antitrypsin) gene are associated with severe chronic rhinosinusitis unresponsive to medical therapy.

Background Alpha-1-antitrypsin (AAT) is a serine protease inhibitor that blocks the protease, neutrophil elastase. Previous population studies have suggested that heterozygote status for the AAT gene (SERPINA1) is a risk factor for chronic rhinosinusitis with nasal polyposis (CRSwNP). This implies a potential genetic predisposition to CRS tied to AAT deficiency. The purpose of this study was to investigate the association between single nucleotide polymorphisms (SNPs) in the SERPINA1 gene and CRS. Methods DNA extracted from a population of 206 patients diagnosed with CRSwNPs and 196 postal code–matched controls was used. A maximally informative set of tagging SNPs from SERPINA1 on chromosome 14q were selected from the HapMap data set (International HapMap Consortium, Nature 437:1299–1320, 2005) and genotyped on the Sequenom platform (Sequenom, San Diego, CA). Results Successful genotyping was performed for 32 of 33 SNPs. Two SNPs (rs1243168 and rs4900229) located upstream of the SERPINA1gene, were associated with CRS. Individuals homozygous (TT)for these SNPs had an increased probability of having CRS with an odds ratio of 5.95 and 1.49, respectively. Subgroup analysis according to severity of disease identified each SNP to be increasingly common in individuals as disease severity increased (p < 0.001). These individuals were also less likely to be responsive to medical therapy (p < 0.001). Conclusions Polymorphisms of the SERPINA1 gene are associated with clinically severe CRS. These results, from a small subset of individuals with CRS, suggest that defects in AAT may be implicated in a subset of individuals unresponsive to conventional therapy and suggests that alternate therapies may be required for their management.

Active smoking status in chronic rhinosinusitis is associated with higher serum markers of inflammation and lower serum eosinophilia

Smoking negatively affects postoperative evolution in patients with chronic rhinosinusitis (CRS); however, the mechanism remains incompletely described. In the lung, smoking increases expression of proinflammatory genes and is associated with an elevation of inflammatory serum markers. Our objective is to determine the impact of smoking on these biomarkers in CRS.

c-MET pathway involvement in chronic rhinosinusitis: A genetic association analysis

Objective: The c-MET receptor and its ligand hepatocyte growth factor (HGF) has been shown to be overexpressed in tissue from chronic rhinosinusitis (CRS) patients with nasal polyps compared with that from controls. We assessed the genetic association of polymorphisms in the met proto-oncogene (MET) gene with CRS. Study Design: Case-control genetic association study. Setting: Tertiary-care university hospital. Subjects and Methods: A total of 206 unrelated Canadian patients with CRS and 196 control subjects were enrolled. Subjects were genotyped for 33 polymorphisms in the MET gene. Results: The allelic association analysis showed eight single nucleotide polymorphisms in the MET gene (rs38850, rs38855, rs38857, rs2237717, rs2402118, rs193688, rs1621, rs42336) with a statistically significant association with CRS. The rs38850 T allele showed the strongest association and the highest risk for CRS (P = 0.004; odds ratio 1.65, 95% confidence interval 1.18-2.32); the association did not reach statistical significance after adjustment for genomic control (P = 0.06). The haplotype TGG constructed of markers rs38850, rs38855, and rs38857 represented a risk haplotype, resulting in a P value of 0.003 that remained significant after correction for multiple testing (P = 0.018). Conclusion: These data suggest that polymorphisms in the MET gene may play a role in the susceptibility to develop CRS. Study findings apply to patients with severe CRS unresponsive to surgery.

Expression of the extracellular matrix gene periostin is increased in chronic rhinosinusitis and decreases following successful endoscopic sinus surgery.

The extracellular matrix (ECM) is a potentially important component of mucosal immunity. ECM dysregulation in chronic rhinosinusitis (CRS) is suggested by genomewide association studies identifying ECM genes as top candidates. Further support is afforded by the demonstration of increased expression of periostin (POSTN) in CRS biopsy samples compared to controls, and by reported roles in eosinophilic inflammation and steroid responsiveness. We wished to evaluate the potential utility of POSTN as a biomarker for disease activity by determining whether POSTN levels were modified in disease and whether they were modulated by endoscopic sinus surgery (ESS).

Topical Probiotics as a Therapeutic Alternative for Chronic Rhinosinusitis: A Preclinical Proof of Concept:

Introduction Patients with chronic rhinosinusitis (CRS) have been shown to manifest a high inflammatory phenotype, with a sinus microbiome deficient in gram-positive bacteria. Gram-positive bacteria are capable of downregulating proinflammatory host responses via an interleukin (IL) 10 mediated response and may represent a potential therapeutic alternative for CRS. We wanted to (i) immunoprofile the IL-10 induction capacity of two gram-positive probiotic strains and (ii) verify the tolerance of these strains by the sinus epithelium. Methods A peripheral blood mononuclear cell (PBMC) challenge model was used to document probiotic induction of IL-10 and tumor necrosis factor (TNF) alpha responses at various bacterial dilutions. Epithelial cell tolerance was demonstrated by using a primary epithelial cell model derived from patient biopsy specimens (six patients total [three with CRS and three controls]). After an incubation period with either a live or a heat-killed probiotic strain, cell viability was assessed by using light microscopy. Results Both probiotic strains induced high IL-10 secretion in PBMCs, with differing profiles of TNF alpha production. Microscopic evaluation after probiotic incubation demonstrated intact cell viability for all cell cultures. Conclusion We identified well-tolerated, nonpathogenic, “generally recognized as safe” status gram-positive probiotics with anti-inflammatory properties. Topical probiotics represented a potential novel topical therapeutic strategy for CRS relevant for further clinical evaluation.

A pooling-based genomewide association study identifies genetic variants associated with Staphylococcus aureus colonization in chronic rhinosinusitis patients.

Staphylococcus aureus (S. aureus) has been implicated in the pathogenesis of chronic rhinosinusitis (CRS). However, host factors contributing to susceptibility to S. aureus colonization in CRS remain unknown. We wish to investigate, using a pooled genomewide association study (pGWAS), single‐nucleotide polymorphisms (SNPs) associated with S. aureus carriage in CRS patients.