Unraveling the Genetic Basis of Aspirin Hypersensitivity in Asthma Beyond Arachidonate Pathways

Although aspirin-exacerbated respiratory disease (AERD) has attracted a great deal of attention because of its association with severe asthma, it remains widely under-diagnosed in the asthmatic population. Oral aspirin challenge is the best method of diagnosing AERD, but this is a time-consuming procedure with serious complications in some cases. Thus, development of non-invasive methods for easy diagnosis is necessary to prevent unexpected complications of aspirin use in susceptible patients. For the past decade, many studies have attempted to elucidate the genetic variants responsible for risk of AERD. Several approaches have been applied in these genetic studies. To date, a limited number of biologically plausible candidate genes in the arachidonate and immune and inflammatory pathways have been studied. Recently, a genome-wide association study was performed. In this review, the results of these studies are summarized, and their limitations discussed. In addition to the genetic variants, changes in methylation patterns on CpG sites have recently been identified in a target tissue of aspirin hypersensitivity. Finally, perspectives on application of new genomic technologies are introduced; these will aid our understanding of the genetic pathogenesis of aspirin hypersensitivity in asthma.

Asthma-Predictive Genetic Markers in Gene Expression Profiling of Peripheral Blood Mononuclear Cells

PURPOSE: We sought to identify asthma-related genes and to examine the potential of these genes to predict asthma, based on expression levels. METHODS: The subjects were 42 asthmatics and 10 normal healthy controls. PBMC RNA was subjected to microarray analysis using a 35K array; t-tests were used to identify genes that were expressed differentially between the two groups. A multiple logistic regression analysis was applied to the differentially expressed genes, and area under the curve (AUC) values from receiver operating characteristic (ROC) curves were obtained. RESULTS: In total, 170 genes were selected using the following criteria: P or =2-fold change. Among these genes, 57 were up-regulated and 113 were down-regulated in asthmatics versus normal controls. A multiple logistic regression analysis was done using more stringent criteria (P or =5-fold change), and eight genes were selected as candidate asthma biomarkers. Using these genes, 255 models (2(8)-1) were generated. Among them, only 85 showed P< or =0.05 by multiple logistic regression analysis. Based on the AUCs from ROC curves for the 85 models, we found that the best model consisted of the genes MEPE, MLSTD1, and TRIM37. The model showed 0.9928 of the AUC with 98% sensitivity and 80% specificity. CONCLUSIONS: MEPE, MLSTD1, and TRIM37 may be useful biomarkers for asthma.

Protection of leukotriene receptor antagonist against aspirin-induced bronchospasm in asthmatics

PURPOSE: Leukotriene receptor antagonists (LTRAs) are used to treat aspirin-intolerant asthma (AIA); however, the protective effects of long-term LTRA administration against aspirin-induced bronchospasm have not been evaluated. OBJECTIVES: We investigated the efficacy of a 12-week treatment with a LTRA in protecting against aspirin-induced asthma in AIA patients. METHODS: Fifty-two adult patients with AIA underwent an aspirin challenge test just before administration of montelukast (10 mg/day) and just after 12 weeks of treatment. The protective effect was assessed as the disappearance of aspirin-induced bronchospasm after 12 weeks of treatment. The results were compared according to the patients' clinical and physiological parameters. RESULTS: The decline in FEV1 following aspirin challenge was significantly reduced from 28.6+/-1.9% to 10.2+/-1.7% (P=0.0001) after 12 weeks of montelukast treatment. However, 14 subjects (30%) still showed a positive response (>15% decline in FEV1) to aspirin challenge. Grouping the subjects into good and poor responders according to post-treatment responses revealed that the pretreatment aspirin-induced FEV1 decline was significantly greater in the poor responders and that the triggering dose of aspirin and the induction time for a positive response were lower and shorter, respectively, in the poor responders. Histories of aspirin hypersensitivity and sinusitis were more prevalent among the poor responders than among the good responders. CONCLUSIONS: Twelve weeks of treatment with montelukast protected against aspirin-induced bronchospasm in 70% of the AIA cases. A poor response was associated with more severe aspirin-induced bronchospasms before treatment and a history of aspirin hypersensitivity or sinusitis. CLINICAL IMPLICATIONS: A severe response to aspirin challenge may be a predictor of poor responsiveness to leukotriene antagonist treatment.

Association analysis of peroxisome proliferator-activated receptors gamma gene polymorphisms with asprin hypersensitivity in asthmatics

PURPOSE: Peroxisome proliferator-activated receptors (PPARs) are transcriptional factors activated by ligands of the nuclear hormone receptor superfamily. The activation of PPARgamma regulates inflammation by downregulating the production of Th2 type cytokines and eosinophil function. In addition, a range of natural substances, including arachidonate pathway metabolites such as 15-hydroxyeicosatetranoic acid (15-HETE), strongly promote PPARG expression. Therefore, genetic variants of the PPARG gene may be associated with the development of aspirin-intolerant asthma (AIA). We investigated the relationship between single nucleotide polymorphism (SNP) of the PPARG gene and AIA. METHODS: Based on the results of an oral aspirin challenge, asthmatics (n=403) were categorized into two groups: those with a decrease in FEV1 of 15% or greater (AIA) or less than 15% (aspirin-tolerant asthma, ATA). We genotyped two single nucleotide polymorphisms in the PPARG gene from Korean asthmatics and normal controls (n=449): +34C>G (Pro12Ala) and +82466C>T (His449His). RESULTS: Logistic regression analysis showed that +82466C>T and haplotype 1 (CC) were associated with the development of aspirin hypersensitivity in asthmatics (P=0.04). The frequency of the rare allele of +82466C>T was significantly higher in AIA patients than in ATA patients in the recessive model [P=0.04, OR=3.97 (1.08-14.53)]. In addition, the frequency of PPARG haplotype 1 was significantly lower in AIA patients than in ATA patients in the dominant model (OR=0.25, P=0.04). CONCLUSIONS: The +82466C>T polymorphism and haplotype 1 of the PPARG gene may be linked to increased risk for aspirin hypersensitivity in asthma.

Association analysis of peroxisome proliferator-activated receptors gamma gene polymorphisms with asprin hypersensitivity in asthmatics

PURPOSE: Peroxisome proliferator-activated receptors (PPARs) are transcriptional factors activated by ligands of the nuclear hormone receptor superfamily. The activation of PPARgamma regulates inflammation by downregulating the production of Th2 type cytokines and eosinophil function. In addition, a range of natural substances, including arachidonate pathway metabolites such as 15-hydroxyeicosatetranoic acid (15-HETE), strongly promote PPARG expression. Therefore, genetic variants of the PPARG gene may be associated with the development of aspirin-intolerant asthma (AIA). We investigated the relationship between single nucleotide polymorphism (SNP) of the PPARG gene and AIA. METHODS: Based on the results of an oral aspirin challenge, asthmatics (n=403) were categorized into two groups: those with a decrease in FEV1 of 15% or greater (AIA) or less than 15% (aspirin-tolerant asthma, ATA). We genotyped two single nucleotide polymorphisms in the PPARG gene from Korean asthmatics and normal controls (n=449): +34C>G (Pro12Ala) and +82466C>T (His449His). RESULTS: Logistic regression analysis showed that +82466C>T and haplotype 1 (CC) were associated with the development of aspirin hypersensitivity in asthmatics (P=0.04). The frequency of the rare allele of +82466C>T was significantly higher in AIA patients than in ATA patients in the recessive model [P=0.04, OR=3.97 (1.08-14.53)]. In addition, the frequency of PPARG haplotype 1 was significantly lower in AIA patients than in ATA patients in the dominant model (OR=0.25, P=0.04). CONCLUSIONS: The +82466C>T polymorphism and haplotype 1 of the PPARG gene may be linked to increased risk for aspirin hypersensitivity in asthma.

The Vision and Satisfaction According to Postoperative Refractive Error after AMO Array(R) Multifocal Intraocular Lens Insertion

PURPOSE: To evaluate the visual outcome and satisfaction according to postoperative refractive error in patient with cataract surgery using AMO Array(R) multifocal intraocular lens. METHODS: According to postoperative refractive errors, 120 eyes (80 patients) were inserted the AMO Array(R) multifocal intraocular lens and were divided into three groups respectively: 28 eyes were myopic group (-0.50 ~ -1.50D), 74 eyes were emetropic group (-0.50 ~ +0.50D) and 18 eyes were hyperopic group (+0.50 ~ +1.50D). In each group, distant vision, near vision and contrast sensitivity test were measured. Also the patients were questioned on their satisfaction. RESULTS: Three months after the operation, the distance uncorrected visions of the myopic, emmetropic and hyperopic group were 0.42 +/- 0.23, 0.73 +/- 0.22, 0.36 +/- 0.28 and the near uncorrected visions were 0.47 +/- 0.18, 0.65 +/- 0.03, 0.41 +/- 0.14 in each. There were no difference in satisfaction, contrast sensitivity and glare visual acuity between three groups. CONCLUSIONS: In cataract surgery using the AMO Array(R) multifocal intraocular lens, we could get the best uncorrected visual acuity in emmetopic group. There were no difference in satisfaction and vision between myopic and hyperopic group. Thus, at the time of cataract operation, the multifocal intraocular lens power should be set on emmetropia in order to improve the vision and satisfaction.