The Effects of Nedocromil Sodium and Cetirizine HCl on Exercise-induced Arterial Hypoxemia in Highly-trained Swimmers

Study Overview
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Brief Summary
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Exercise-induced arterial hypoxemia (EIAH), a reduced amount of oxygen in the arterial blood during exercise, has been observed in otherwise healthy, highly-trained endurance athletes during exercise at sea level. The extent of the arterial deoxygenation may be influenced by a histamine-mediated inflammatory response at the pulmonary capillary-alveolar membrane limiting oxygen diffusion. Moreover, while EIAH has been routinely explored in running and cycling, swimming is understudied despite potential mechanistic avenues which may put swimmers at further risk for EIAH. The purpose of this study is threefold: 1) to determine whether highly-trained swimmers experience EIAH during submaximal and maximal exercise, 2) to determine the extent to which histamine release influences oxyhemoglobin saturation during swimming exercise, and 3) to determine whether nedocromil sodium (NS), a mast cell stabilizer, and cetirizine HCl (CH), an H1-receptor competitive inhibitor, can improve oxyhemoglobin saturation during submaximal and maximal swimming exercise. Twenty-six (13 men, 13 women) highly-trained swimmers will complete an intense swimming protocol to assess the histamine response to intense exercise. A subset with the highest histamine responses will participate in three additional sessions (placebo, NS, and CH conditions) which will include a swimming aerobic capacity test and 5-minutes of swimming at both 70 and 85% of their maximal oxygen uptake.

Detailed Description
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For the first testing session, participants will report to the Indiana University Human Performance Laboratory to complete a medical screening and, if willing, consent to the procedures of the study. The medical screening will include measurements of height, weight, resting heart rate, resting blood pressure, and resting pulmonary function along with a health history questionnaire. The second testing session consists of an assessment of risk factors for development of EIAH, specifically changes in blood biomarkers pre- and post-swimming exercise. Participants will report to the Counsilman-Billingsley Aquatics Center and complete an exercise protocol designed to elicit an inflammatory response. Venous blood draws will be performed to assess participants' pre-exercise complete blood count and pre- and post-intense exercise concentrations of plasma IL-1β, IL-8, plasma histamine, whole blood histamine, and histamine release. Measurements of hemoglobin concentration and hematocrit will also be performed pre- and post-exercise in order to correct biomarker concentrations for fluid loss during exercise. Swimmers of each sex that exhibit the largest histamine release will be selected for further study until at least four swimmers of each sex complete all three experimental trials. Participants that exhibit increases in inflammatory markers following swimming exercise will visit the Human Performance Laboratory on three occasions separated by at least 48 hours and no more than 60 days. Apart from receiving a placebo (PL) or different drug treatment (nedocromil sodium, NS; cetirizine HCl, CH) prior to exercise, participants will perform identical protocols on each visit to the laboratory. Participants will report to the lab and consume either a placebo or CH pill, followed by a health history update questionnaire and their resting pulmonary function will be measured. Participants will then complete a self-selected warm-up that will be standardized across all three testing sessions, followed by administration of either a placebo or NS through an inhaler and instrumentation. The exercise protocol beings with a progressive swimming test to maximum aerobic capacity (V̇O2max) in a swimming flume, followed by two constant load work bouts at approximately 70 and 85% of the previously recorded HRmax while peripheral capillary oxyhemoglobin saturation (SpO2) is continuously monitored. Participants will receive a 20-min break between each work bout. Drug treatments will be assigned in a double-blind, randomized crossover fashion such that each participant receives each treatment. Concentrations of plasma histamine, whole blood histamine, and histamine release will be assessed from pre- and post-exercise blood samples.

Official Title
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The Effects of Nedocromil Sodium and Cetirizine HCl on Exercise-induced Arterial Hypoxemia in Highly-trained Swimmers

Conditions
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Exercise-induced Arterial Hypoxemia

Intervention / Treatment
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* Drug: Nedocromil Sodium
* Drug: Cetirizine HCl
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men and women 18-35 years old Current collegiate or professional swimmer Currently training at least 300 minutes per week Self-reported to be healthy Exclusion Criteria: Not within defined age range Current diagnosis of or using medication for: Severe allergies Asthma Exercise-induced asthma Exercise-induced bronchoconstriction Pulmonary function test considered to be abnormal (defined as forced vital capacity (FVC) <80% of predicted, forced expiratory volume in one second (FEV1) <80% predicted, and/or FEV1/FVC ratio >5% of the predicted ratio) Hypertension during screening (systolic blood pressure >139 or diastolic blood pressure >89) Current tobacco or electronic cigarette use or consistent use within the last 2 years A contraindication for use of nedocromil sodium: Previous adverse reaction to nedocromil sodium or a similar medication Use of fast-acting, inhaled insulin A contraindication for use of cetirizine HCl: Previous adverse reaction to cetirizine HCl or a similar medication Allergy to the food additives E218 or E216 An intolerance to or inability to absorb some sugars, such as lactose or sorbitol Liver or kidney failure Epilepsy or similar condition A condition that makes urinating difficult Use of midodrine or ritonavir Are pregnant or could possibly be pregnant by self-report Subjects with current, irregular menstrual cycles (amenorrhea) or who had irregular menstruation patterns for greater than one year People who answer 'yes' to any of the pre-participation screening questions on page one of the PAR-Q+ questionnaire.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Experimental group<br>This subset of 8 individuals will complete all 3 experimental study visits, and will ingest either 1) a placebo pill and placebo inhaler contents, 2) a placebo pill and nedocromil sodium (4 mg), or 3) a cetirizine HCl pill (10 mg) and placebo inhaler contents in a randomized order and double-blind fashion. This group will be composed of individuals who have a high histamine response to intense exercise. | Drug: Nedocromil Sodium<br>* Eight participants will be administered 4 mg of nedocromil sodium to examine whether this drug can improve their oxyhemoglobin saturation during exercise.<br>* Other names: Tilade;Drug: Cetirizine HCl<br>* Eight participants will be administered 10 mg of cetirizine HCl to examine whether this drug can improve their oxyhemoglobin saturation during exercise.<br>* Other names: Zyrtec;Other: Placebo<br>* The placebo pill is a sugar-free gelatin pill casing. The placebo inhaler contains isotonic saline.<br>|
| Placebo Comparator: Control-only group<br>This subset of 4 individuals will complete one of the experimental study visits, and will ingest either a placebo pill and placebo inhaler contents. This group will be composed of individuals who have a low histamine response to intense exercise. | Other: Placebo<br>* The placebo pill is a sugar-free gelatin pill casing. The placebo inhaler contains isotonic saline.<br>|
| No Intervention: Selection pool<br>Twenty-six total individuals will be recruited for the initial portion of the study, and the aforementioned 12 (8 experimental, 4 control-only) will be a subset of the initial 26. The other 14 participants will not take part in further study. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peripheral capillary oxyhemoglobin saturation | SpO2 percentage measured via a standard bedside pulse oximetry unit | During the procedure (all 8-20 minutes of the aerobic capacity test and each of the two 5-minute constant load trials) in Visits 3, 4, and 5 of the study |