Cerebral Blood Flow and Ventilatory Responses During Sleep in Normoxia and Intermittent Hypoxia

Phase 1

Not yet recruiting

• Conditions: Blood Pressure; Hypoxia, Brain; Sleep Disorder; Stroke; Endothelial Dysfunction; Obstructive Sleep Apnea of Adult; Sleep Apnea; Oxidative Stress
• Interventions: Drug: Drug Lowering Cerebral Blood Flow (CBF) and Normoxia Sleep; Drug: Placebo and Normoxia Sleep; Drug: Placebo and Intermittent Hypoxia Sleep; Drug: Drug Lowering CBF and Intermittent Hypoxia Sleep

• Registration Number: NCT03255408
• Lead Sponsor: University of Calgary

Brief Summary

A prospective double blind, placebo-controlled, randomized cross-over trial to evaluate the effect of lowering cerebral blood flow on the ventilatory chemoreflexes (acute hypoxic and hypercapnic ventilatory responses).

Detailed Description

The investigators will explore the relationship between changes in Cerebral Blood Flow (CBF) and ventilatory chemoreflexes i.e. Acute Ventilatory Response to Hypoxia (AHVR) and Acute Hypercapnic Ventilatory Response (HCVR) before, during and after sleep under normoxic conditions and sleep accompanied by isocapnic Intermittent Hypoxia (IH) among healthy human study participants.

A pharmacological intervention will be utilized to manipulate the CBF in a randomized order. The study participants will also be randomly assigned the order to sleep either under normoxia or IH exposure. The experiments will be separated from one another with an interval of sufficient drug and IH exposure washout period. The venous blood samples and urinary samples will be collected for the vascular biomarkers.

Basic Information
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Recruitment & Eligibility
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Study & Design

Study Timeline

• Study First Submitted: 2017-08-06
• Study First Submitted QC: 2017-08-16
• Study First Posted: 2017-08-21
• Status Verified: 2022-11
• Last Update Submitted: 2022-11-02
• Last Update Posted: 2022-11-04
• Study Start: 2023-01-01
• Primary Completion: 2024-12-30
• Study Completion: 2024-12-30

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 12

Inclusion Criteria

• Healthy adults
• 18 - 45 years of age
• Living in Calgary for the past one year
• Have no medical condition or should not be taking any blood pressure medications.
• The participant should not be lactose intolerant

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Exclusion Criteria

• Cerebrovascular, cardio-respiratory, renal and metabolic diseases
• Bleeding disorders and upper gastrointestinal diseases e.g. peptic ulcer disease
• Pregnancy, obese and sleep-disordered breathing
• Drug allergies to non-steroidal anti-inflammatories
• Currently smoking

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
CBF Lowering and Normoxia Sleep	Drug Lowering Cerebral Blood Flow (CBF) and Normoxia Sleep	Study participants will take drug lowering Cerebral Blood Flow (CBF) and sleep under room air i.e. normoxia exposure.
Placebo and Normoxia Sleep	Placebo and Normoxia Sleep	Study participants will take Placebo that has no effect on Cerebral Blood Flow (CBF) and sleep under room air i.e. normoxia exposure.
Placebo and IH Sleep	Placebo and Intermittent Hypoxia Sleep	Study participants will take Placebo that has no effect on Cerebral Blood Flow (CBF) and sleep under Intermittent Hypoxia (IH) exposure.
CBF Lowering and IH Sleep	Drug Lowering CBF and Intermittent Hypoxia Sleep	Study participants will take drug lowering Cerebral Blood Flow (CBF) and sleep under Intermittent Hypoxia (IH) exposure.

Primary Outcome Measures

Name	Time	Method
Changes in cerebral blood flow and ventilatory chemoreflexes	~18 months (from the starting time of recruiting study participants)	The relationship between changes in cerebral blood flow (CBF) and ventilatory chemoreflexes (acute hypoxic and hypercapnic ventilatory responses) before and after sleeping under normoxia and intermittent hypoxia exposure among healthy human study participants.
Cerebral blood flow responses and ventilatory chemoreflexes during sleep	~18 months (from the starting time of recruiting study participants)	The relationship between cerebral blood flow (CBF) changes and ventilatory chemoreflexes (acute hypoxic and hypercapnic ventilatory responses) during sleep under normoxia and intermittent hypoxia exposure among healthy human study participants.

Secondary Outcome Measures

Name	Time	Method
Changes in reactive oxygen species and vascular biomarkers	~24 months (from the starting time of recruiting study participants)	The changes in vascular biomarkers such as nitric oxide, reactive oxygen species and exosome analysis or urinary prostaglandins before and after sleep under normoxia and intermittent hypoxia exposure with cerebral blood flow changes.