Influence of Genetic Variation of the Alpha-Subunit of the Epithelial Sodium Channel (ENaC) on Baseline Pulmonary Function and Exhaled Sodium Ions (Na+) and Chloride Ions (Cl-) in Healthy Subjects and Patients with Cystic Fibrosis

Persistent Link:
http://hdl.handle.net/10150/614485
Title:
Influence of Genetic Variation of the Alpha-Subunit of the Epithelial Sodium Channel (ENaC) on Baseline Pulmonary Function and Exhaled Sodium Ions (Na+) and Chloride Ions (Cl-) in Healthy Subjects and Patients with Cystic Fibrosis
Author:
Foxx-Lupo, William T.; Snyder, Eric M.
Affiliation:
College of Pharmacy, The University of Arizona
Issue Date:
2012
Rights:
Copyright © is held by the author.
Collection Information:
This item is part of the Pharmacy Student Research Projects collection, made available by the College of Pharmacy and the University Libraries at the University of Arizona. For more information about items in this collection, please contact Jennifer Martin, Associate Librarian and Clinical Instructor, Pharmacy Practice and Science, jenmartin@email.arizona.edu.
Publisher:
The University of Arizona.
Abstract:
Specific Aims: The epithelial sodium channels (ENaC) found on the apical membranes of epithelial cells including those lining the respiratory tract are the rate limiting step of the absorption of excess fluid from the airspace of the alveoli. ENaC function is modulated by the effects of various physiologic signals such as the adrenergic and purinergic pathways, in addition to other local channels which control the flow of negatively charged ions such as the cystic fibrosis transmembrane conductance regulator (CFTR). We sought to determine the influence of genetic variation on the alpha subunit of ENaC at amino acid position 663 on baseline exhaled ions and pulmonary function in patients with CF. Methods: We assessed pulmonary function ( forced vital capacity[FVC], forced expiratory volume in one second [FEV1], forced expiratory flow maximum[FEFmax]) using a Medical Graphics cardiopulmonary testing device (Minneapolis, MN). Measures of exhaled sodium (Na+) and chloride (Cl-) were obtained using exhaled breathe condensate collected on a Jaeger Ecoscreen condenser unit (Cardinal Health, Yorba Linda, CA) with Na+ quantification using an atomic absorption spectrophotometer (Analyst 100; Perkin Elmer, Norwalk, CT) and Cl- anion quantification using a Dionex AS11 HC column. Healthy n=31 (n=18[58%], 9[29%], and 4[13%] subjects; Body mass index (BMI)=23±1, 25±2, and 25±2kg/ m2 for AA, AT and TT groups respectively). CF n= 42 (n=33[79%], 7[16%], and 2[5%] subjects; BMI equals 23±7, 19±0.4, and 20±2.2kg/m2 for AA, AT and TT groups respectively). Main Results: We found that the distribution of genotypes in CF differed from healthy subjects, with the AA genotype in 80% of CF and 59% in healthy. No significant difference were demonstrated in healthy subjects between genotype groups for pulmonary function and exhaled chloride while the genotypes did differ in exhaled Na (Na=2.9±0.4, 1.7±0.3, and 3.7±1.1mmol/L for AA, AT, and TT respectively, ANOVA p=0.07). CF subjects with the AA genotype had a higher baseline exhaled Cl-, FEV1, and FEFmax than those in the AA group (Cl=0.125±0.038,0.0 27±0.007, and 0.033±0.02 mmol/L ; FEV1=71±5, 68±11, and 40±22L; FEFmax=86±4, 72±7, and 44±24L/sec; for AA, AT, and TT respectively, ANOVA p<0.05, Tukey [AA vs. TT] p<0.05) while exhaled Na+ and FVC were similar between genotypes. Conclusions: Our results suggest that CF subjects with the AA genotype of the alpha subunit of the ENaC have a higher baseline exhaled Cl- and a resulting increase in pulmonary function when compared to the overactive TT groupCF patients with the TT αENaC genotype are likely candidates for early identification and treatment with inhaled ENaC inhibitors or other modulators of this pathway in order to improve survival.
Description:
Class of 2012 Abstract
Keywords:
sodium ions (Na+); chloride ions (Cl-); epithelial sodium channel (ENaC); genetic; pulmonary; cystic fibrosis; cystic fibrosis transmembrane conductance regulator (CFTR).
Advisor:
Snyder, Eric M.

Full metadata record

DC FieldValue Language
dc.contributor.advisorSnyder, Eric M.en
dc.contributor.authorFoxx-Lupo, William T.en
dc.contributor.authorSnyder, Eric M.en
dc.date.accessioned2016-06-23T19:07:08Z-
dc.date.available2016-06-23T19:07:08Z-
dc.date.issued2012-
dc.identifier.urihttp://hdl.handle.net/10150/614485-
dc.descriptionClass of 2012 Abstracten
dc.description.abstractSpecific Aims: The epithelial sodium channels (ENaC) found on the apical membranes of epithelial cells including those lining the respiratory tract are the rate limiting step of the absorption of excess fluid from the airspace of the alveoli. ENaC function is modulated by the effects of various physiologic signals such as the adrenergic and purinergic pathways, in addition to other local channels which control the flow of negatively charged ions such as the cystic fibrosis transmembrane conductance regulator (CFTR). We sought to determine the influence of genetic variation on the alpha subunit of ENaC at amino acid position 663 on baseline exhaled ions and pulmonary function in patients with CF. Methods: We assessed pulmonary function ( forced vital capacity[FVC], forced expiratory volume in one second [FEV1], forced expiratory flow maximum[FEFmax]) using a Medical Graphics cardiopulmonary testing device (Minneapolis, MN). Measures of exhaled sodium (Na+) and chloride (Cl-) were obtained using exhaled breathe condensate collected on a Jaeger Ecoscreen condenser unit (Cardinal Health, Yorba Linda, CA) with Na+ quantification using an atomic absorption spectrophotometer (Analyst 100; Perkin Elmer, Norwalk, CT) and Cl- anion quantification using a Dionex AS11 HC column. Healthy n=31 (n=18[58%], 9[29%], and 4[13%] subjects; Body mass index (BMI)=23±1, 25±2, and 25±2kg/ m2 for AA, AT and TT groups respectively). CF n= 42 (n=33[79%], 7[16%], and 2[5%] subjects; BMI equals 23±7, 19±0.4, and 20±2.2kg/m2 for AA, AT and TT groups respectively). Main Results: We found that the distribution of genotypes in CF differed from healthy subjects, with the AA genotype in 80% of CF and 59% in healthy. No significant difference were demonstrated in healthy subjects between genotype groups for pulmonary function and exhaled chloride while the genotypes did differ in exhaled Na (Na=2.9±0.4, 1.7±0.3, and 3.7±1.1mmol/L for AA, AT, and TT respectively, ANOVA p=0.07). CF subjects with the AA genotype had a higher baseline exhaled Cl-, FEV1, and FEFmax than those in the AA group (Cl=0.125±0.038,0.0 27±0.007, and 0.033±0.02 mmol/L ; FEV1=71±5, 68±11, and 40±22L; FEFmax=86±4, 72±7, and 44±24L/sec; for AA, AT, and TT respectively, ANOVA p<0.05, Tukey [AA vs. TT] p<0.05) while exhaled Na+ and FVC were similar between genotypes. Conclusions: Our results suggest that CF subjects with the AA genotype of the alpha subunit of the ENaC have a higher baseline exhaled Cl- and a resulting increase in pulmonary function when compared to the overactive TT groupCF patients with the TT αENaC genotype are likely candidates for early identification and treatment with inhaled ENaC inhibitors or other modulators of this pathway in order to improve survival.en
dc.language.isoen_USen
dc.publisherThe University of Arizona.en
dc.rightsCopyright © is held by the author.en
dc.subjectsodium ions (Na+)en
dc.subjectchloride ions (Cl-)en
dc.subjectepithelial sodium channel (ENaC)en
dc.subjectgeneticen
dc.subjectpulmonaryen
dc.subjectcystic fibrosisen
dc.subjectcystic fibrosis transmembrane conductance regulator (CFTR).en
dc.titleInfluence of Genetic Variation of the Alpha-Subunit of the Epithelial Sodium Channel (ENaC) on Baseline Pulmonary Function and Exhaled Sodium Ions (Na+) and Chloride Ions (Cl-) in Healthy Subjects and Patients with Cystic Fibrosisen_US
dc.typetexten
dc.typeElectronic Reporten
dc.contributor.departmentCollege of Pharmacy, The University of Arizonaen
dc.description.collectioninformationThis item is part of the Pharmacy Student Research Projects collection, made available by the College of Pharmacy and the University Libraries at the University of Arizona. For more information about items in this collection, please contact Jennifer Martin, Associate Librarian and Clinical Instructor, Pharmacy Practice and Science, jenmartin@email.arizona.edu.en
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