Insulin Sensitivity During Hyperbaric Oxygen Compared to Hyperbaric Air (HOTAIR4)
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|ClinicalTrials.gov Identifier: NCT03138746|
Recruitment Status : Not yet recruiting
First Posted : May 3, 2017
Last Update Posted : May 3, 2017
In a recent series of studies performed by our group, we have shown that exposure to hyperbaric oxygen (HBO) leads to an increase in insulin sensitivity in male subjects with type-2 diabetes (T2DM) and in obese and overweight men without diabetes. The aim of this study is to investigate the relationship between pressure and oxygen in producing this effect, specifically, is this effect measurable in hyperbaric air or is some higher pressure of oxygen required?
- To determine whether the insulin sensitising effect of HBO is apparent in hyperbaric air at the same pressure as HBO.
- To examine mechanisms underpinning the increase in insulin sensitivity following HBO.
|Condition or disease||Intervention/treatment|
|Diabetes Mellitus, Type II Insulin Resistance||Procedure: HBO Procedure: Hyperbaric air|
All participants will attend the Hyperbaric Medicine Unit on 4 occasions and metabolic testing will be undertaken at the same time of the day. Day 1 will be for baseline assessment. Days 2 to 4 will be on consecutive days the following week. An overnight fast (10-hours) will be required prior to each day.
Day 1. Baseline assessment. The participant will attend at 0900 for a hyperinsulinaemic euglycaemic clamp, which will be performed with the same protocol as used in our three previous clamp studies. Two intravenous cannulae are inserted into veins in contralateral forearms using local anaesthetic (lignocaine 1%). Baseline blood is taken for fasting glucose and insulin and a primed insulin infusion is started (80mU/m2/min) for 3 hours. Blood samples (<2mls) are obtained at 5-10 minute intervals so that blood glucose can be maintained at 5.5 mmol/L with a variable infusion of 25% Dextrose and a trained individual will be present for the duration of the clamping procedure. Insulin sensitivity will be assessed by the steady state glucose infusion rate calculated over a stable 30-minute period of the clamp. Assessments will be made at two points during the 3-hour clamp; at 2-2½ hours and 2½-3 hours. Immediately post-clamp, volunteers are given orange juice and high carbohydrate lunch, and the glucose infusion is maintained on halving scale for 5 minutes each for at least 20 minutes. Blood sugar levels are monitored every 10-15 minutes for 60 minutes. Total blood taken during the clamping procedure will be less than 100mls including baseline samples. The researchers have performed several hundred clamps.
Day 2. The following week, the participant will attend at 1015 to undergo a routine 2-hour HBO session, 10:90:30 profile (compression of the chamber in air to 2 atmospheres absolute, then donning a "hood" supplying high flow oxygen for 90-minutes followed by a linear decompression back to 1 atmosphere over 30 minutes). Blood will be taken for glucose, insulin and inflammatory markers (30mls) before and after HBO. Food will be provided.
Day 3. The participant will undergo a second routine HBO session. Blood will be taken for glucose, insulin and inflammatory markers (30mls) before and after HBO. Food will be provided.
Day 4. The participant will attend at 0900 for a second 3-hour hyperinsulinaemic euglycaemic clamp, similar to Day1. The procedure for the two groups (HBO and hyperbaric air) will be identical, the only difference will be the breathing gas used during the 10:90:30 hyperbaric exposures. The breathing gas delivered to the participant (oxygen or air) will be supplied from masked "research" gas outlets, so the participant will be blinded as to which group they are in. The participant will enter the chamber after a 1-hour clamp stabilising period and assessment of the steady state glucose infusion rate will take place at similar times to Day1. This means that during the 2-hour hyperbaric exposure, the assessment periods will correspond to 1-1½ hours (pressure constant at 2 atmospheres absolute) and 1½-2 hours (the 30-minute decompression at the end of the session). Post clamp will be managed as during Day1.
With blood taken during 2 clamps (less than 100mls each) and 4 by 30 ml samples on Days 2 and 3, total blood taken will be less than 320 ml over a 7-day period.
|Study Type :||Observational|
|Estimated Enrollment :||40 participants|
|Official Title:||Insulin Sensitivity During Hyperbaric Oxygen Compared to Hyperbaric Air|
|Estimated Study Start Date :||June 2017|
|Estimated Primary Completion Date :||February 2018|
|Estimated Study Completion Date :||February 2018|
On day 4, the participant will undergo a 2-hour hyperbaric exposure breathing 100% oxygen
Compression in a hyperbaric chamber in air to 2 atmospheres absolute, then donning a "hood" supplying high flow oxygen for 90-minutes followed by a linear decompression back to 1 atmosphere over 30 minutes
On day 4, the participant will undergo a 2-hour hyperbaric exposure breathing air
Procedure: Hyperbaric air
Compression in a hyperbaric chamber in air to 2 atmospheres absolute, then donning a "hood" supplying high flow air for 90-minutes followed by a linear decompression back to 1 atmosphere over 30 minutes
- insulin sensitivity [ Time Frame: Baseline to Day 4 ]As measured by the glucose infusion rate during the steady-state phase of the hyperinsulinaemic euglycaemic clamp on day 4
- insulin sensitivity [ Time Frame: Baseline to Day 3 ]as assessed by single specimen fasting models (HOMA and QUICKI) on Days 2 and 3
- change in inflammatory cytokines [ Time Frame: Day 2 and 3 ]analysis of serum inflammatory markers pre and post HBO on Days 2 and 3
Biospecimen Retention: Samples Without DNA
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03138746
|Contact: David C Wilkinson, FANZCA||+61 8 8222 firstname.lastname@example.org|
|Contact: Leonie K Heilbronn, PhD||+61 8 8128 email@example.com|
|Australia, South Australia|
|Hyperbaric Medicine Unit, Royal Adelaide Hospital||Not yet recruiting|
|Adelaide, South Australia, Australia, 5000|
|Contact: David C Wilkinson, FANZCA 61 8 8222 5116 firstname.lastname@example.org|
|Principal Investigator: David C Wilkinson, FANZCA|
|Sub-Investigator: Ian M Chapman, PhD|
|Sub-Investigator: Leonie K Heilbronn, PhD|
|Principal Investigator:||David C Wilkinson, FANZCA||University of Adelaide|