An observational study in Cerebrovascular Regulation, sponsored by University of British Columbia. Not yet recruiting. Open to participants aged 7 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2024-03-06.
Sponsored by University of British Columbia · Observational
Tight regulation of brain blood flow is integral for delivery of oxygen and energy for survival. During childhood, the brain has a twofold higher metabolic requirement, thus requires greater blood flow to match this. Despite this knowledge, brain blood flow responses and the mechanisms of regulation during maturation are largely unknown. Thus, we are trying to understand what happens to blood vessel function and the mechanisms of regulation at rest and during handgrip exercise. This will give us valuable information on brain blood vessel responses, which will help future interventions aimed at improving blood vessel function in youth, for future disease prevention. Utilizing the pubertal transition will provide insights into the influence of sex hormones on brain blood flow regulation.
The goal of this cross-sectional observational study is to examine the influence of age and maturation on cerebral blood flow regulation, achieved through exploring the responses to increases in carbon dioxide concentrations, and static handgrip exercise in children (7-10 years), adolescents (12-16 years) and young adults (19-35 years).
The main questions the study aims to answer are:
During all protocols, participants will have their end-tidal gas concentrations measured and/or altered using prospective end-tidal gas targeting using a computer controlled gas blender system in which we have obtained Health Canada approval for.
The goal of this cross-sectional experimental study to determine the influence age, sex and pubertal status on cerebrovascular responses at rest and during isometric exercise.
The main objective is to investigate the regulatory mechanisms of cerebral blood flow during hypercapnia and isometric exercise, and determine whether any mechanistic differences in regulation are present with advancing age and maturation.
The following questions will be addressed in 20 healthy children (7-10 years), 20 healthy adolescents (12-16 years) and 20 young healthy adults (19-35 years), to compare the influence of age, sex and maturation on these responses, as follows:
To control and manipulate breathing gases during the study protocols, the partial pressures of end-tidal carbon dioxide and oxygen will be sampled at the mouth using the Investigational Testing Authorization approved computer controlled gas blender system. To target specific end-tidal carbon dioxide and oxygen levels during the clamped breathing and hypercapnic trials respectively, prospective end-tidal gas targeting will be utilized. The system allows for breath-by-breath regulation of end-tidal gases, independently of ventilation. End-tidal concentrations are prospectively targeted by controlling the inspired concentration of carbon dioxide and oxygen according to the previous expired breath, allowing this to be precisely controlled throughout the duration of the protocol. Gas analysis, and spirometry measures of tidal volume and breathing frequency will be recorded using the computer controlled system. Prospective end-tidal gas targeting is safe, with all inspired gases containing oxygen, with rigorous control procedures and fail-safe mechanisms which do not allow inhaled gases to fall outside of safe thresholds.
University of British Columbia is the lead sponsor of 1,309 studies on the registry; 253 are open to participants now.
Of its 6 completed or terminated interventional studies of FDA-regulated products, 1 (17%) have results posted.
Counted across the registry records on this site, refreshed daily.
The study population will be healthy children, adolescents and adults between the ages of 7-10 years, 12-16 years or 19-35 years of age. Participants will be recruited from the general population from online advertisements and media, targeting children, adolescents and adults residing in the Okanagan, British Columbia.
Exclusion Criteria:
All groups of the experiment will be exposed to the same intervention. The intervention the participants are exposed to is the use of the computer controlled gas blender system for manipulation of end-tidal and arterial blood gases. This will be used for the following protocols, to either clamp end-tidal concentrations at resting levels or administer a hypercapnia challenge. The protocol includes assessment of cerebral blood flow responses (measured using ultrasound) to carbon dioxide; including a hypercapnia ramp protocol followed by a transient protocol. Following at least 30 minute wash out, participants will then perform isometric exercise at 30% of their maximal voluntary contraction for 2 minutes. Participants will perform the isometric handgrip exercise under 2 different conditions (hypercapnia (+9 mmHg) and clamped breathing; to maintain baseline end-tidal carbon dioxide and oxygen concentrations) with a 20-minute recovery period between each bout.
Device: RespirACT RA-MR System
All groups of the experiment will be exposed to the same intervention. The intervention the participants are exposed to is the use of the computer controlled gas blender system for manipulation of end-tidal and arterial blood gases. This will be used for the following protocols, to either clamp end-tidal at resting levels or administer a hypercapnia challenge. The protocol includes assessment of cerebral blood flow responses (measured using ultrasound) to carbon dioxide; including a hypercapnia ramp protocol followed by a transient protocol. Following at least 30 minute wash out, participants will then perform isometric exercise at 30% of their maximal voluntary contraction for 2 minutes. Participants will perform the isometric handgrip exercise under 2 different conditions (hypercapnia (+9 mmHg) and clamped breathing; to maintain baseline end-tidal carbon dioxide and oxygen concentrations) with a 20-minute recovery period between each bout.
Device: RespirACT RA-MR System
All groups of the experiment will be exposed to the same intervention. The intervention the participants are exposed to is the use of the computer controlled gas blender system for manipulation of end-tidal and arterial blood gases. This will be used for the following protocols, to either clamp end-tidal at resting levels or administer a hypercapnia challenge. The protocol includes assessment of cerebral blood flow responses (measured using ultrasound) to carbon dioxide; including a hypercapnia ramp protocol followed by a transient protocol. Following at least 30 minute wash out, participants will then perform isometric exercise at 30% of their maximal voluntary contraction for 2 minutes. Participants will perform the isometric handgrip exercise under 2 different conditions (hypercapnia (+9 mmHg) and clamped breathing; to maintain baseline end-tidal carbon dioxide and oxygen concentrations) with a 20-minute recovery period between each bout.
Device: RespirACT RA-MR System
RespirAct RA-MR™ is a computer-controlled gas blender to implement precise control of blood gases for a consistent and repeatable stimulus.
Cerebral blood flow
Ultrasound assessment of the internal carotid artery blood flow
Time frame: Experimental visit (1 day)
Cerebral blood velocity
Ultrasound assessment of the middle cerebral artery velocity
Time frame: Experimental visit (1 day)
Beat-by-beat blood pressure
Continuous assessment of mean arterial pressure responses
Time frame: Experimental visit (1 day)
Saliva hormone concentrations
Saliva specimen samples for the assessment of estrogen, progesterone, dehydroepiandrosterone and testosterone for the characterization of maturation status
Time frame: Experimental visit (1 day)
Physical activity questionnaire
Self report assessments of physical activity levels will be assessed
Time frame: Experimental visit (1 day)
Anthropometrics: weight
Body mass (kg) will be measured with electronic scales
Time frame: Experimental visit (1 day)
Gas analysis
The partial pressures of end-tidal carbon dioxide and oxygen will be sampled at the mouth from a fitted respiratory face mask.
Time frame: Experimental visit (1 day)
Anthropometrics: height
Stature standing and sitting height will be measured (cm).
Time frame: Experimental visit (1 day)
No study locations are listed for this record.
Plan to share: Yes — Pseudonymized data from this study will be made available for sharing with other investigators, after publication of the study's key papers. Data will be shared through the Federated Research Data Repository (FRDR) (https://www.frdr-dfdr.ca/repo/). This is a secure data repository, which is searchable on the www, it is managed by Library Services. A digital object identifier (DOI) will be generated for datasets as they are deposited to the repository. Data will be stored in this repository for a minimum of 10 years or for 10 years from the last date of access.
This study is not yet recruiting, as verified in Mar 2024. You cannot join it, but the record below documents what was studied.
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University of British Columbia