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Relationships Between Folate and Asthma Severity Among Baltimore City Children and Adolescents
201
Rhinovirus 16 (RV16) Induces Airway Hyperresponsiveness (AHR) and Differential Mediator Release in Human lung slices ex vivo C. J. Koziol-White1, P. R. Cooper1, W. Lee2, J. E. Gern2, A. Haczku1, R. A. Panettieri1; 1University of Pennsylvania, Philadelphia, PA, 2University of Wisconsin, Madison, WI. RATIONALE: Rhinovirus (RV) respiratory infections commonly evoke asthma exacerbations in children and adults with asthma but precise molecular mechanisms mediating RVeffects in human airways remain unknown. We hypothesized that ex vivo RV16 exposure alters agonist-mediated bronchoconstriction/bronchodilation and mediator release in structural cells of human small airways. METHODS: Human lung tissue was inflated with 2% agarose and core samples, containing small airways, were sliced into 250 mm sections and collected in Ham’s F-12 media. Slices were exposed ex vivo to increasing concentrations of RV16 for 24 or 48 hr, and culture supernatants assessed for mediator release. In parallel, carbachol-induced brochoconstriction and beta agonist-induced bronchodilation was measured. RESULTS: Exposure of human small airways to RV16 significantly augmented, by half-log (p50.03), carbachol-induced bronchoconstriction at 48 hr but not at 24 hr (p50.15), and had little effect on beta agonist-induced _5 bronchodilation. At both 24 and 48 hr, IP-10 release was increased (> fold) as compared to control. IL-8 expression increased, but GM-CSF, IL-1b, and SP-D release were not affected by RV16 exposure. Importantly, the increased sensitivity of the airways to carbachol and proinflammatory mediator release occurred independently of viral infection. CONCLUSIONS: These data suggest that selective inflammatory mediator release by structural cells after viral exposure occurs in the absence of trafficking leukocytes. Given that RV16 enhances airway responsiveness without infection, novel therapeutic targets for virus-induced asthma exacerbations may focus not only on prevention of infection, but also on the physiological effects of early viral exposure.
202
Relationship of Airway Hyperresponsiveness (AHR) and RGS2 Expression in Asthma T. T. Nguyen, Y. Xie, A. I. Berro, Y. Tu, T. B. Casale; Creighton University Medical Center, Omaha, NE. RATIONALE: G-protein coupled receptor (GPCR) signaling pathways are involved in airway contraction, and GPCR agonists and antagonists are used in treatment of asthma. Some regulators of G-protein signaling (RGS) proteins inhibit GPCRs and may be important in asthma pathophysiology. Indeed, we found that RGS2 knock-out mice have increased AHR, equivalent to allergen sensitization. We therefore studied whether RGS2 expression is lower in human asthmatics and if the degree of AHR was related to RGS2 expression using isolated monocytes as a model. METHODS: 15 non-atopic, non-asthmatic subjects and 15 treatment na€ıve atopic mild-to-moderate asthmatics underwent methacholine challenge to determine degree of AHR, measured by PD20. Peripheral blood monocytes from these subjects were isolated and purified. Monocyte RGS2 mRNA expression was measured by quantitative RT-PCR and RGS2 protein expression was measured by western blot with b-actin serving as a control. This study was approved by the IRB and all subjects provided written informed consent. RESULTS: Monocyte RGS2 mRNA levels (x10,000, mean + SD) were 3716171 and 2336128 in normals and asthmatics, respectively (P50.025). Monocyte RGS2/b-actin protein levels were 0.10560.035 in normals vs. 0.06160.017 in asthmatics (P50.22). Correlation of RGS2 mRNA levels with AHR (PD20) in asthmatic subjects demonstrated a Pearson coefficient of 0.713 (P50.009). CONCLUSIONS: As postulated, both RGS2 mRNA expression and protein levels are lower in asthmatics, and amongst asthmatics, there is a statistically significant correlation between lower AHR (higher PD20) and higher RGS2 mRNA expression. Future studies aimed at elucidating the exact role of RGS2 in asthma could lead to new therapeutic opportunities.
203
Proof of Concept Study of Serum Vitamin D Levels and Markers of Asthma Severity in Children and Adults D. A. Searing, E. Goleva, A. H. Liu, J. R. Murphy, D. Y. Leung; National Jewish Health, Denver, CO. RATIONALE: Evidence is accumulating that low vitamin D levels show a relationship with increased inhaled corticosteroid (ICS) requirement, increased allergic inflammation, and decreased lung function. Additional information is needed in a prospective fashion to further elucidate relationships between vitamin D and clinical variables. METHODS: We performed a prospective analysis of 25-hydroxyvitamin D [25(OH)D] levels in 104 pediatric and adult asthmatics, as well as 101 age-matched controls. Demographic and clinical data were recorded. Multivariate linear regression was used to determine an efficient model associating demographic and clinical factors with 25(OH)D levels. RESULTS: Asthmatics did not have different 25(OH)D levels than the control group (mean 18.4 and 18.5, respectively). BMI (p<0.0001) and body surface area (p<0.0001) showed a significant inverse relationship with 25()H)D levels, whereas supplemental vitamin D use (p<0.0001) showed a direct relationship with 25(OH)D levels. African American adults had significantly lower 25(OH)D levels (mean 10.9 ng/mL) than African American children (mean 21.3 ng/mL; p<0.0001). In patients with asthma, multivariate analysis controlling for demographic factors showed a significant inverse relationship between ICS dose (p50.01), total IgE (p50.0002), sensitization to house dust mite (p50.003 for D. farinae, p50.002 for D. Pteronyssinus), wheezing on exam (p50.02), and 25(OH)D level. CONCLUSIONS: In this prospective study, asthmatics did not show different levels of vitamin D than the general population. In adult and pediatric asthmatics, however, abnormal physical exam findings and requirements for higher ICS doses were associated with lower 25(OH)D levels.
204
Relationships Between Folate and Asthma Severity Among Baltimore City Children and Adolescents J. H. Lin1, W. Matsui1, J. N. Saams1, R. D. Peng2, E. C. Matsui1; 1Johns Hopkins University School of Medicine, Baltimore, MD, 2Johns Hopkins Bloomberg School of Public Health, Baltimore, MD. RATIONALE: Sufficient folate is required for robust inflammatory responses, but higher folate is associated with less inflammation. This non-linear dose-response relationship between folate and inflammation suggests that relationships between folate and asthma may be complex. METHODS: 143 children (5-17y) with asthma underwent skin testing (SPT), spirometry, and fractional exhaled nitric oxide (FeNO) measurement. Serum folate, total IgE, and cytokines were measured. Asthma-related acute visits in the previous 3 months were captured by questionnaire. Relationships between folate and outcomes were examined using linear and logistic regression models with dummy variables for folate quartiles. _1+SPT; 91%), AfricanRESULTS: Most participants were atopic (> Americans (92%) receiving public health insurance (85%). Folate(ng/ mL) quartiles were: (Q1(0.2-9), Q2(9.1-16.5), Q3(16.6-21), Q4(21.250)). FEV1/FVC was lowest in Q2 and increased from Q2-Q4 (FEV1/ FVC(%), mean6SD: Q2(77611.7), Q3(81611.2), Q4(8267.2)). However, FEV1/FVC was higher in Q1(8269.1) than Q2. Similar nonlinear relationships were observed between folate and IgE(kU/L)(median [IQR]: Q1(134 [3.4-3523]); Q2(393[7.8-2979]); Q3(190[4.3-4096]); Q4 (138[7.95-1241])) and FeNO(ppb)(Q1(27[6-128]); Q2(43[7-153]); Q3 (32[2.5-210]); Q4(28[5-145])). IgE was significantly higher (p50.005) and FEV1/FVC significantly lower (p50.026) in Q2 vs. Q1. Prevalence of acute visits was lowest in Q1 and Q4 (Q1(55%); Q2(62%); Q3(73%); Q4(43%); Q4 vs. Q1-3 (p50.033)). Serum IL-4 and IL-5 had similar non-linear relationships with folate (e.g. IL5(pg/mL), mean6SD: Q1 (1.262.0); Q2(1.661.8); Q3(1.261.2); Q4(1.060.8)). CONCLUSIONS: Higher folate is associated with better lung function and decreased inflammation and acute visits, as is deficient/insufficient folate. Since optimal lymphocyte function requires folate, deficient/insufficient folate may be associated with less inflammation and milder asthma. However, folate>20ng/mL appears optimal for minimizing inflammation and acute asthma visits and maximizing lung function.
SATURDAY
Abstracts AB55
J ALLERGY CLIN IMMUNOL VOLUME 127, NUMBER 2
Rhinovirus 16 (RV16) Induces Airway Hyperresponsiveness (AHR) and Differential Mediator Release in Human lung slices ex vivo C. J. Koziol-White1, P. R. Cooper1, W. Lee2, J. E. Gern2, A. Haczku1, R. A. Panettieri1; 1University of Pennsylvania, Philadelphia, PA, 2University of Wisconsin, Madison, WI. RATIONALE: Rhinovirus (RV) respiratory infections commonly evoke asthma exacerbations in children and adults with asthma but precise molecular mechanisms mediating RVeffects in human airways remain unknown. We hypothesized that ex vivo RV16 exposure alters agonist-mediated bronchoconstriction/bronchodilation and mediator release in structural cells of human small airways. METHODS: Human lung tissue was inflated with 2% agarose and core samples, containing small airways, were sliced into 250 mm sections and collected in Ham’s F-12 media. Slices were exposed ex vivo to increasing concentrations of RV16 for 24 or 48 hr, and culture supernatants assessed for mediator release. In parallel, carbachol-induced brochoconstriction and beta agonist-induced bronchodilation was measured. RESULTS: Exposure of human small airways to RV16 significantly augmented, by half-log (p50.03), carbachol-induced bronchoconstriction at 48 hr but not at 24 hr (p50.15), and had little effect on beta agonist-induced _5 bronchodilation. At both 24 and 48 hr, IP-10 release was increased (> fold) as compared to control. IL-8 expression increased, but GM-CSF, IL-1b, and SP-D release were not affected by RV16 exposure. Importantly, the increased sensitivity of the airways to carbachol and proinflammatory mediator release occurred independently of viral infection. CONCLUSIONS: These data suggest that selective inflammatory mediator release by structural cells after viral exposure occurs in the absence of trafficking leukocytes. Given that RV16 enhances airway responsiveness without infection, novel therapeutic targets for virus-induced asthma exacerbations may focus not only on prevention of infection, but also on the physiological effects of early viral exposure.
202
Relationship of Airway Hyperresponsiveness (AHR) and RGS2 Expression in Asthma T. T. Nguyen, Y. Xie, A. I. Berro, Y. Tu, T. B. Casale; Creighton University Medical Center, Omaha, NE. RATIONALE: G-protein coupled receptor (GPCR) signaling pathways are involved in airway contraction, and GPCR agonists and antagonists are used in treatment of asthma. Some regulators of G-protein signaling (RGS) proteins inhibit GPCRs and may be important in asthma pathophysiology. Indeed, we found that RGS2 knock-out mice have increased AHR, equivalent to allergen sensitization. We therefore studied whether RGS2 expression is lower in human asthmatics and if the degree of AHR was related to RGS2 expression using isolated monocytes as a model. METHODS: 15 non-atopic, non-asthmatic subjects and 15 treatment na€ıve atopic mild-to-moderate asthmatics underwent methacholine challenge to determine degree of AHR, measured by PD20. Peripheral blood monocytes from these subjects were isolated and purified. Monocyte RGS2 mRNA expression was measured by quantitative RT-PCR and RGS2 protein expression was measured by western blot with b-actin serving as a control. This study was approved by the IRB and all subjects provided written informed consent. RESULTS: Monocyte RGS2 mRNA levels (x10,000, mean + SD) were 3716171 and 2336128 in normals and asthmatics, respectively (P50.025). Monocyte RGS2/b-actin protein levels were 0.10560.035 in normals vs. 0.06160.017 in asthmatics (P50.22). Correlation of RGS2 mRNA levels with AHR (PD20) in asthmatic subjects demonstrated a Pearson coefficient of 0.713 (P50.009). CONCLUSIONS: As postulated, both RGS2 mRNA expression and protein levels are lower in asthmatics, and amongst asthmatics, there is a statistically significant correlation between lower AHR (higher PD20) and higher RGS2 mRNA expression. Future studies aimed at elucidating the exact role of RGS2 in asthma could lead to new therapeutic opportunities.
203
Proof of Concept Study of Serum Vitamin D Levels and Markers of Asthma Severity in Children and Adults D. A. Searing, E. Goleva, A. H. Liu, J. R. Murphy, D. Y. Leung; National Jewish Health, Denver, CO. RATIONALE: Evidence is accumulating that low vitamin D levels show a relationship with increased inhaled corticosteroid (ICS) requirement, increased allergic inflammation, and decreased lung function. Additional information is needed in a prospective fashion to further elucidate relationships between vitamin D and clinical variables. METHODS: We performed a prospective analysis of 25-hydroxyvitamin D [25(OH)D] levels in 104 pediatric and adult asthmatics, as well as 101 age-matched controls. Demographic and clinical data were recorded. Multivariate linear regression was used to determine an efficient model associating demographic and clinical factors with 25(OH)D levels. RESULTS: Asthmatics did not have different 25(OH)D levels than the control group (mean 18.4 and 18.5, respectively). BMI (p<0.0001) and body surface area (p<0.0001) showed a significant inverse relationship with 25()H)D levels, whereas supplemental vitamin D use (p<0.0001) showed a direct relationship with 25(OH)D levels. African American adults had significantly lower 25(OH)D levels (mean 10.9 ng/mL) than African American children (mean 21.3 ng/mL; p<0.0001). In patients with asthma, multivariate analysis controlling for demographic factors showed a significant inverse relationship between ICS dose (p50.01), total IgE (p50.0002), sensitization to house dust mite (p50.003 for D. farinae, p50.002 for D. Pteronyssinus), wheezing on exam (p50.02), and 25(OH)D level. CONCLUSIONS: In this prospective study, asthmatics did not show different levels of vitamin D than the general population. In adult and pediatric asthmatics, however, abnormal physical exam findings and requirements for higher ICS doses were associated with lower 25(OH)D levels.
204
Relationships Between Folate and Asthma Severity Among Baltimore City Children and Adolescents J. H. Lin1, W. Matsui1, J. N. Saams1, R. D. Peng2, E. C. Matsui1; 1Johns Hopkins University School of Medicine, Baltimore, MD, 2Johns Hopkins Bloomberg School of Public Health, Baltimore, MD. RATIONALE: Sufficient folate is required for robust inflammatory responses, but higher folate is associated with less inflammation. This non-linear dose-response relationship between folate and inflammation suggests that relationships between folate and asthma may be complex. METHODS: 143 children (5-17y) with asthma underwent skin testing (SPT), spirometry, and fractional exhaled nitric oxide (FeNO) measurement. Serum folate, total IgE, and cytokines were measured. Asthma-related acute visits in the previous 3 months were captured by questionnaire. Relationships between folate and outcomes were examined using linear and logistic regression models with dummy variables for folate quartiles. _1+SPT; 91%), AfricanRESULTS: Most participants were atopic (> Americans (92%) receiving public health insurance (85%). Folate(ng/ mL) quartiles were: (Q1(0.2-9), Q2(9.1-16.5), Q3(16.6-21), Q4(21.250)). FEV1/FVC was lowest in Q2 and increased from Q2-Q4 (FEV1/ FVC(%), mean6SD: Q2(77611.7), Q3(81611.2), Q4(8267.2)). However, FEV1/FVC was higher in Q1(8269.1) than Q2. Similar nonlinear relationships were observed between folate and IgE(kU/L)(median [IQR]: Q1(134 [3.4-3523]); Q2(393[7.8-2979]); Q3(190[4.3-4096]); Q4 (138[7.95-1241])) and FeNO(ppb)(Q1(27[6-128]); Q2(43[7-153]); Q3 (32[2.5-210]); Q4(28[5-145])). IgE was significantly higher (p50.005) and FEV1/FVC significantly lower (p50.026) in Q2 vs. Q1. Prevalence of acute visits was lowest in Q1 and Q4 (Q1(55%); Q2(62%); Q3(73%); Q4(43%); Q4 vs. Q1-3 (p50.033)). Serum IL-4 and IL-5 had similar non-linear relationships with folate (e.g. IL5(pg/mL), mean6SD: Q1 (1.262.0); Q2(1.661.8); Q3(1.261.2); Q4(1.060.8)). CONCLUSIONS: Higher folate is associated with better lung function and decreased inflammation and acute visits, as is deficient/insufficient folate. Since optimal lymphocyte function requires folate, deficient/insufficient folate may be associated with less inflammation and milder asthma. However, folate>20ng/mL appears optimal for minimizing inflammation and acute asthma visits and maximizing lung function.
SATURDAY
Abstracts AB55
J ALLERGY CLIN IMMUNOL VOLUME 127, NUMBER 2