Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT06164665 |
| Other study ID # |
22-07H |
| Secondary ID |
|
| Status |
Completed |
| Phase |
Phase 4
|
| First received |
|
| Last updated |
|
| Start date |
March 1, 2023 |
| Est. completion date |
July 1, 2023 |
Study information
| Verified date |
December 2023 |
| Source |
United States Army Research Institute of Environmental Medicine |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Apparent hypoxia-induced insulin insensitivity along with alterations in glucose kinetics
suggests reduction in glucose uptake by the peripheral tissue is a primary factor
contributing to reductions in exogenous glucose oxidation at HA. As such, the primary
objective of this study is to determine the ability of an insulin sensitizer (Pioglitazone,
PIO) to enhance exogenous glucose oxidation and metabolic clearance rate during
metabolically-matched, steady-state exercise during acute HA exposure compared to placebo
(PLA) in native lowlanders. Secondary objective of this study will be to assess the impact of
PIO on markers of inflammation and iron status compared to PLA. This randomized crossover
placebo control double blinded study will examine substrate oxidation and glucose kinetic
responses to ingesting supplemental carbohydrate (glucose) during metabolically-matched,
steady-state exercise with acute (~5 h) exposure to HA (460 mmHg, or 4300m, barometric
pressure similar to Pike's Peak) after receiving PIO (HA+PIO), or after receiving a matched
placebo (HA+PLA). Eight healthy, recreationally active males between the ages of 18-39 yrs
will be required to complete this study. Following a 4 day glycogen normalization period
receiving PIO or PLA daily, volunteers will complete two 80-min trials, performing
metabolically-matched, steady-state aerobic (same absolute workload corresponding to ~55 ± 5%
of V̇O2peak at HA) exercise on a treadmill, and consuming 145 g of glucose (1.8 g/min); one
trial with HA+PIO and the other with HA+PLA. A dual glucose tracer (13C-glucose oral
ingestion and [6,6-2H2]-glucose primed, continuous infusion) technique and indirect
calorimetry will be used to selectively analyze endogenous and exogenous glucose oxidation,
as well as glucose rate of appearance (Ra), disappearance (Rd) and metabolic clearance rate
(MCR). Serial blood samples will be collected during each trial to assess endocrine and
circulating substrate responses to exercise, carbohydrate, and hypoxia with or without PIO.
All trials will occur at the same time of day in the USARIEM hypobaric/hypoxic chamber and be
separated by a minimum 10-d washout period. The primary risks associated with this study
include those associated with acute hypobaric hypoxia, exercise, and blood sampling.
Description:
This randomized crossover placebo controlled double blinded study will examine substrate
oxidation and glucose kinetic responses to ingesting supplemental carbohydrate (glucose)
during metabolically-matched, steady-state exercise with acute (~5 h) exposure to HA (460
mmHg) after short-term (5 days) use of Pioglitazone (HA+PIO), or matched placebo (HA+PLA).
Eight healthy, recreationally active males between the ages of 18-39 yrs will be enrolled.
Following a 48-hr muscle glycogen normalization period, volunteers will complete 80-min of
metabolically-matched, steady-state (same absolute workload corresponding to ~55 ± 5% of
V̇O2peak at HA) exercise on a treadmill, and consume 145 g of glucose (1.8 g/min) with HA+PIO
and HA+PLA. A dual glucose tracer (13C-glucose oral ingestion and [6,6-2H2]-glucose primed,
continuous infusion) technique and indirect calorimetry will be used to analyze endogenous
and exogenous glucose oxidation, as well as glucose rate of appearance (Ra), disappearance
(Rd), and MCR. Serial blood samples will be collected during each trial to assess endocrine
and circulating substrate responses to exercise, carbohydrate, and hypoxia, with or without
PIO. Isotope methodology and aerobic exercise protocols will be identical to our previous
work (3, 4), allowing comparison of outcomes across studies. All trials will be conducted in
the USARIEM hypobaric/hypoxic chamber and be separated by a minimum 10-d washout period.
