Tatsuo Yukawa

Thromboxane A2 receptor +795T>C and chemoattractant receptor-homologous molecule expressed on Th2 cells -466T>C gene polymorphisms in patients with aspirin-exacerbated respiratory disease.

It is well known that aspirin-exacerbated respiratory disease (AERD) is more common in women than in men, however, whether gene polymorphisms of the thromboxane A2 receptor (TBXA2R) and chemoattractant receptor-homologous molecules expressed on Th2 cells (CRTH2) are associated with the susceptibility of AERD remains unknown. In this study, we examined the gene polymorphisms in a Japanese population. DNA specimens were obtained from the following three groups: 96 patients with AERD, 500 patients with aspirin-tolerant asthma (ATA) and 100 normal controls. The target DNA sequence of each gene was amplified, and an allelic discrimination assay for single nucleotide polymorphisms relating to expression of each gene was carried out. The frequencies of the CC/CT genotype of TBXA2R +795T>C were higher than those of the TT genotype in AERD patients compared to ATA patients (P=0.015). In female AERD patients, but not in males, frequencies of the CC/CT genotype were higher than those of the TT genotype of TBXA2R +795T>C compared to female ATA patients (P=0.013). Also, frequencies of the TT genotype of CRTH2 -466T>C were higher than those of the CC/CT genotype in AERD patients compared to ATA patients (P=0.034). In female AERD patients, but not in male, frequencies of the TT genotype were higher than those of the CC/CT genotype of CRTH2 -466T>C in AERD patients compared to female ATA patients (P=0.046). Based on our investigations, no significant relationship was found between the genotype and the clinical characteristics according to these gene polymorphisms in AERD patients. Our results suggest that an association between the TBXA2R and CRTH2 gene polymorphisms with AERD may exist in the Japanese population.

Arg16Gly β2-Adrenergic Receptor Gene Polymorphism in Japanese Patients with Aspirin-Exacerbated Respiratory Disease

Background: There has been no report that investigated β2-adrenergic receptor (ADRB2) gene polymorphism in patients with aspirin-exacerbated respiratory disease (AERD). Methods: DNA in the specimens in three groups of study subjects classified patients with AERD, patients with aspirin-tolerant asthma (ATA) and normal controls was extracted, and the target DNA sequence of the ADRB2 was amplified using a set of primers to generate an amplicon of 219 bp in length. Allelic discrimination assay for single nucleotide polymorphisms relating to the ADRB2 gene expression was carried out by using a previously described single nucleotide polymorphism detective system, sequence-specific thermal-elution chromatography. Results: The frequency of the Gly variant allele in patients with AERD was significantly lower than that in patients with ATA (p = 0.007), and the odds ratio (OR) of AERD to ATA associated with wild-type ArgArg homozygote was 3.300. Frequencies of wild-type ArgArg homozygote are significantly higher than those of variant-type ArgGly/GlyGly genotype in patients with AERD compared with those with ATA (p < 0.001, OR = 3.153). In patients with AERD, frequencies of wild-type ArgArg homozygote in both female and male patients are significantly higher than those of variant-type ArgGly/GlyGly genotype in male patients compared with those with ATA (p < 0.001, OR = 5.128 and p = 0.007, OR = 4.367, respectively). Also, in patients with AERD, frequencies of wild-type ArgArg homozygote in female patients are significantly higher than those of variant-type ArgGly/GlyGly genotype in female patients compared with those with ATA (p = 0.002, OR = 2.825). Conclusions: We were the first to analyze Arg16Gly ADRB2 gene polymorphism in Japanese patients with AERD, and showed that Arg16Gly ADRB2 gene polymorphism in Japanese patients with AERD is different from that in the patients with ATA.

Changes in airway responsiveness and β‐ and α‐adrenergic receptors in the lungs of guinea pigs with experimental asthma

The effects of inhaled allergen on airway responsiveness and on β‐ and α‐1‐adrenergic receptors on lung membrane were investigated in guinea pigs. After measuring the respiratory threshold to histamine (RT‐HIS), one group of guinea pigs passively sensitized for ovalbumin was challenged by allergen inhalation (challenged group). Measurement of the RT‐HIS 24 h following challenge revealed a significant decrease from 687 μg/ml (mean, n= 16) to 407 μg/ml (P < 0.05). In addition the RT‐HIS 24 h after challenge was also significantly lower in the challenged group than in controls (n= 9, P < 0.05). The density of α‐adrenergic receptors on the lung membrane of the challenged group was 594 ± 32 (mean ± SE) fmol/mg protein (n= 11) compared with 712 ± 24 fmol/mg protein (n= 9) in the controls, a statistically significant difference (P < 0.05). A significant correlation was found between the RT‐HIS and density of β‐adrenergic receptors. From these results, we concluded that the exaggerated airway responsiveness 24 h after allergen challenge is in part due to a decrease in the density of P‐adrenergic receptors. There was no difference in the density of β‐1‐adrenergic receptors nor a significant correlation between the RT‐HIS and the number of α‐1‐adrenergic receptors in the challenged vs. the control groups.

IL-13 and IL-17A gene polymorphisms in Japanese patients with aspirin-exacerbated respiratory disease

BACKGROUND The role of interleukin (IL) 13 and IL-17A in aspirin-exacerbated respiratory disease (AERD) remains unknown. OBJECTIVE To analyze the IL-13 and IL-17A gene polymorphisms in Japanese patients with AERD. METHODS The single-nucleotide polymorphisms in each gene were examined in patients with AERD, patients with aspirin-tolerant asthma (ATA), and healthy controls. RESULTS Frequencies of the TT/CT genotype of the IL-13 -1111C>T gene were higher than frequencies of the CC genotype in AERD patients compared with ATA patients (P < .001). In female patients with AERD, frequencies of the TT/CT genotype were higher than those of the CC genotype compared with female patients with ATA (P < .001). However, genotype frequencies of IL-13 Arg110Gln did not differ between AERD and ATA patients. Frequencies of the CC genotype of the IL-17A -737C>T gene were higher than those of the TT/CT genotype in AERD patients compared with ATA patients (P = .02). In female patients with AERD, frequencies of the CC genotype were higher than those of the TT/CT genotype compared with female patients with ATA (P = .03). Forced expiratory volume in 1 second (percentage predicted) in AERD patients with the CC genotype of the IL-13 -1111C>T gene was lower than that in the patients with the TT/CT genotype. AERD patients with the TT/CT genotype of the IL-17A -737C>T gene had a higher peripheral total eosinophil count compared with the patients with the CC genotype. The comparison of the clinical characteristics according to the IL-13 Arg110Gln gene polymorphism showed no difference. CONCLUSIONS These findings suggest that the IL-13 -1111C>T and IL-17A -737C>T gene sequence variations might have a role in the development of AERD.

Heat shock protein 70 gene polymorphisms in Japanese patients with aspirin-exacerbated respiratory disease.

Background Aspirin-exacerbated respiratory disease (AERD) is nonatopic asthma, and the role of heat shock protein (HSP) 70 in AERD remains unknown. We analyzed HSP70 gene polymorphisms in Japanese patients with AERD. Methods The single-nucleotide polymorphisms in HSPA1B-179C>T and 1267A>G gene were examined in patients with AERD and those with aspirin-tolerant asthma (ATA). All patients were in a stable condition. Results There were significant differences in total serum IgE levels, peripheral blood eosinophil count, and prevalence of atopy between AERD and ATA. The patients with AERD showed higher frequencies of the CT/TT genotype of the HSPA1B-179C>T than that of the CC genotype compared to ATA (P < 0.001). They showed higher frequencies of the GG genotype of the HSPA1B1267A>G than that of the GA/AA genotype compared to ATA (P < 0.001). These differences were irrespective of the sex for the genotypes analyzed. The frequency of HSPA1B-179C/1267A haplotype was significantly higher in AERD compared to ATA (P < 0.001; odds ratio, 3.154; 95% confidence interval, 1.916-5.193). Among the clinical and hematological characteristics investigated, AERD showed a significant variance in peripheral blood eosinophil count according to the association of the 2 HSP70 gene polymorphisms (P = 0.033), but not in ATA. Conclusions Our findings first suggest that the association between HSPA1B-179C>T and 1267A>G gene sequence variations might be implicated in the development of AERD.

Recent advance in investigation of gene polymorphisms in Japanese patients with aspirin-exacerbated respiratory disease

Aspirin-exacerbated respiratory disease (AERD) is a complex clinical syndrome characterised by severe asthmatic attack upon treatment with aspirin and/or non-steroidal anti-inflammatory drugs (NSAIDs). Genetic predisposition has been considered as a crucial determinant and candidate genes have concentrated especially on cysteinyl leukotrienes (LTs)-related genes as the inhibitory action of aspirin and NSAIDs on cyclooxygenase activity may cause overproduction of cysteinyl LTs. However, conflicting results have been reported, in parallel with replication studies in different ethnic groups. Thus, future areas of investigations need to focus on comprehensive approaches towards the discovery of other genetic biomarkers. Unfortunately, few papers have been reported about gene polymorphisms in Japanese patients with AERD. Here, we described on our recent genetic investigations on B2ADR, IL-13, IL-17A, CYP2C19, TBXA2R, CRTH2 and HSP70. This review indicates potential genetic biomarkers contributing to the early diagnosis of AERD, which may include CYP2C19 and HSP70 gene polymorphisms, and future validation studies in independent population are required to provide reassurance about our findings.

Single Nucleotide Polymorphisms in Thymic Stromal Lymphopoietin Gene are not Associated with Aspirin-Exacerbated Respiratory Disease Susceptibility - A Pilot Study in a Japanese Population

Background: Thymic stromal lymphopoietin (TSLP) is an epithelial cell-derived cytokine, implicated in the development and progression of allergic diseases. Several studies indicated polymorphisms in TSLP gene were associated asthma, and two single nucleotides polymorphisms (SNPs) in TSLP (rs1837253 and rs2289276) were shown to be associated with asthma in a sex-specific fashion. However, there has been no report that investigated TSLP gene polymorphisms in patients with aspirin-exacerbated respiratory disease (AERD). Methods: DNA specimens were obtained from the following three groups: 105 patients with AERD, 270 patients with aspirin-tolerant asthma (ATA) and 90 normal controls. The target DNA sequence of the TSLP gene was amplified using a set of primers. Allelic discrimination assay for the two SNPs in TSLP gene (rs1837253 and rs2289276) was carried out. All patients were Japanese, and they were in a stable condition. Results: The frequency of the T minor allele of TSLP -5717C>T in patients with AERD and those with ATA was significantly higher than that in normal controls. There were no significant difference of the T minor allele frequency of TSLP -82C>T among the three groups. Analysis of genotype frequencies of the CT/TT genotype group and CC genotype both in TSLP -5717C>T and in TSLP -82C>T showed no differences between AERD and ATA patients. In addition, subgroup analysis of the genotype frequencies with gender did not differ between AERD and ATA patients. Conclusion: This is the first pilot study to investigate TSLP gene polymorphisms in AERD, which didn’t find an association between the TSLP gene polymorphisms and AERD susceptibility in a Japanese population, suggesting polymorphisms in TSLP gene may contribute to asthma, but not to aspirin hypersensitivity.

Hypothetical Mechanism of Aspirin-Exacerbated Respiratory DiseaseBased on Recent Investigations of Gene Polymorphisms in JapanesePatients

Aspirin-exacerbated respiratory disease (AERD) is characterized by severe asthmatic attack after taking aspirin and/or nonsteroidal anti-inflammatory drugs (NSAIDs). The typical patient with AERD is an adult who develops refractory chronic rhinitis in the third or fourth decade of life. Natural history and clinical features of AERD indicates that during the evaluation of chronic rhinitis persistent bronchial asthma develops, and finally after exposure to NSAID acute respiratory reactions begin to occur. The inhibitory action of aspirin and/or NSAIDs on cyclooxygenase activity may cause diversion to the 5-lipoxygenase pathway, which leads to the overproduction of cysteinyl leukotrienes (LTs). Thus, a general consensus exists that increased levels of cysteinyl LTs are key inflammatory mediators in AERD. As aspirin intolerance is found in a specific population, genetic predisposition has been considered as a crucial determinant. Investigations on candidate genes have been concentrated especially on cysteinyl LTs-related genes, however conflicting results have been reported. So, future areas of investigations need to focus on comprehensive approaches towards other genetic biomarkers. We’ve recently reported possible presence of other gene polymorphisms in Japanese patients with AERD. The natural history and clinical characteristics of AERD indicate that the respiratory mucosal inflammatory process in AERD begins and continues in the absence of ongoing or even intermittent exposure to NSAIDs. So, in this review, we propose a hypothetical progress of AERD over time based on mainly the results of our investigations, and present a schematically sketching the course of NSAIDs-triggered hypersensitivity with genes, such as asthma-associated genes, that may initiate susceptibility to AERD, and that may accelerate pathogenesis and induce onset of AERD. The findings of our studies were based on small-sized samples from a Japanese population, and future validation studies in independent populations are required to provide reassurance about our hypothesis.

Solute Carrier Family 6 Member 12 Gene Polymorphisms in Japanese Patientswith Aspirin-Exacerbated Respiratory Disease

Background: Betaine/gamma-aminobutyric acid (GABA) signaling pathway in the airway epithelium has been revealed to play a critical role in bronchial asthma. To elucidate any genetic influence of the GABAergic in aspirinexacerbated respiratory disease (AERD), we investigated the association of solute carrier family 6 (neurotransmitter transporter, betaine/GABA) member 12 (SLC6A12) gene in Japanese patients with AERD. Methods: DNA specimens were obtained from 103 AERD patients, 300 patients with aspirin-tolerant asthma (ATA) and 100 normal controls. Allelic discrimination assay for two single nucleotides polymorphisms in SLC6A12 gene (rs499368 and rs557881) was carried out. Results: The minor allele frequencies in SLC6A12 intron 2 A>T genotype (rs49936) were higher in AERD patients than in normal controls, and that in SLC6A12 exon 4 T>C genotype (rs557881) were higher in AERD patients than in ATA patients and normal controls. The frequencies of the combined TC/CC genotype group of SLC6A12 exon 4 T>C were higher than those of the TT genotype in AERD patients compared with those in ATA patients (P=0.021; odds ratio, 1.724; 95% confidence interval, 1.087-2.732). In male patients with AERD, frequencies of the TC/CC genotype group were higher than those of the TT genotype compared with male patients with ATA (P = 0.010; odds ratio, 3.177; 95% confidence interval, 1.311-7.699). Forced expiratory volume in one second (percentage predicted) in AERD patients with the TC/CC genotype group of the SLC6A12 exon 4 T>C gene was lower than that in the patients with the TT genotype (P=0.039). Conclusion: This is the first Japanese study to investigate the SLC6A12 intron 2 A>T and SLC6A12 exon 4 T>C genotype polymorphisms in patients with AERD. Our findings suggest that the association between SLC6A12 intron 2 A>T and exon 4 T>C gene sequence variations might be implicated in the development of AERD in a Japanese population.

Effect of Thromboxane A2 Synthetase Inhibitor on Immediate-Type Hypersensitivity Reactions

The effect of the thromboxane (TX) A2 synthetase inhibitor, OKY-046, on human leukocyte histamine release and bronchial hypersensitivity in asthmatic subjects was evaluated. It was found that OKY-046 inhibited IgE- and Ca2+ ionophore A23187-mediated leukocyte histamine release in a dose-dependent fashion (IC50: 1.0 and 3.0 X 10(-3) M, respectively) and that OKY-046 could diminish bronchial hypersensitivity, determined by leukotriene D4 inhalation, following a 2-week oral medication. These data suggest that the TXA2 synthetase inhibitor can produce favorable effects upon the course of immediate-type hypersensitivity reactions.