Outcome
Type |
Measure |
Description |
Time frame |
Safety issue |
Primary |
Changes in integrated fractional synthesis rate (%/d) in response to bed rest with and without ketone monoester (KET) supplementation. |
Integrative myofibrillar fractional synthesis rate will be calculated during baseline (day 0-5) and bed rest (day 5-10) phases. |
Day 0-5 and day 5-10 |
|
Secondary |
Changes in whole body insulin sensitivity in response to bed rest with and without ketone monoester (KET) supplementation. |
Measurements taken in the fasted state before and after bed rest. Will measure blood glucose and insulin concentration during a hyperinsulinemic-euglycemic clamp. |
Day-3 and Day 10. |
|
Secondary |
Changes in whole-body lean mass (kg) in response to bed rest with and without ketone monoester (KET) supplementation |
Measurements taken in the fasted state using dual-energy x-ray absorptiometry (DXA) following urinary void before and after bed rest. |
Day-3 and Day 10. |
|
Secondary |
Changes in leg lean mass (kg) in response to bed rest with and without ketone monoester (KET) supplementation |
Measurements taken in the fasted state using dual-energy x-ray absorptiometry (DXA) following urinary void before and after bed rest. |
Day -3 and Day 10. |
|
Secondary |
Changes in quadriceps muscle volume in response to bed rest with and without ketone monoester (KET) supplementation. |
Measurements taken before and after bed rest via magnetic resonance imaging (MRI). |
Day -3 and Day 10. |
|
Secondary |
Changes in maximal voluntary isometric contraction (N/m) of the knee extensors in response to bed rest with and without ketone monoester (KET) supplementation. |
Measurements taken before and after bed rest using a Biodex dynamometer. |
Day -3 and Day 10. |
|
Secondary |
Changes in handgrip strength (kg) in response to bed rest with and without ketone monoester (KET) supplementation. |
Measurements taken before and after bed rest using a Jamar hand dynamometer. |
Day -3 and Day 10. |
|
Secondary |
Changes in physical performance (numerical score) as determined by short physical performance battery (SPPB) in response to bed rest with and without ketone monoester (KET) supplementation. |
Measurements taken before and after bed rest |
Day -3 and Day 10. |
|
Secondary |
Changes in physical performance (numerical score) as determined by 5-item physical performance test in response to bed rest with and without ketone monoester (KET) supplementation. |
Measurements taken before and after bed rest |
Day -3 and Day 10. |
|
Secondary |
Changes in cognitive status in response to bed rest with and without ketone monoester (KET) supplementation. |
NIH Toolbox Cognition Battery (computerized). Measurements taken before and after bed rest |
Day 4 and Day 9. |
|
Secondary |
Changes in markers of inflammation in systemic circulation in response to bed rest with and without ketone monoester (KET) supplementation. |
Markers of inflammation including: IL-1 beta, NF-K beta 1, IL-6, TNF-alpha, IFNY, MIP-1 beta will be evaluated. Measurements taken before, during, and after bed rest. |
Day -3 and Day 10. |
|
Secondary |
Changes in muscle mRNA expression of inflammatory regulators will be assessed in response to bed rest with and without ketone monoester (KET) supplementation. |
Muscle mRNA expression of NFKB1, TLR-4,IL-6, TNF-alpha, and IL-1Beta will be evaluated. Measurements taken before and after bed rest |
Day -3 and Day 10. |
|
Secondary |
Changes in skeletal muscle phenotype in response to bed rest with and without ketone monoester (KET) supplementation. |
Muscle cross-sections immunolabeled for type I, IIa, and IIx myosin heavy chains. Measurements taken before and after bed rest. |
Day -3 and Day 10. |
|
Secondary |
Changes in skeletal muscle fiber size in response to bed rest with and without ketone monoester (KET) supplementation. |
Muscle cross-sections analyzed for cross-sectional area. |
Day -3 and Day 10. |
|
Secondary |
Changes in mitochondrial content in response to bed rest with and without ketone monoester (KET) supplementation. |
Via the assessment in succinate dehydrogenase activity. |
Day -3 and Day 10. |
|
Secondary |
Changes in mitochondrial respiration in response to bed rest with and without ketone monoester (KET) supplementation. |
Assessed using standard substrate and inhibitor addition protocols in O2k high resolution Respirometer. Measurements taken before and after bed rest. |
Day -3 and Day 10. |
|
Secondary |
Changes in mitochondrial calcium retention capacity (marker of mitochondrial propensity to trigger apoptosis) in response to bed rest with and without ketone monoester (KET) supplementation. |
Determined spectrofluorometrically using the Calcium Green probe. Measurements taken before and after bed rest. |
Day -3 and Day 10. |
|
Secondary |
Changes in mitochondrial reactive oxygen species (ROS) production in response to bed rest with and without ketone monoester (KET) supplementation. |
Assessed using standard substrate and inhibitor addition protocols in O2k high resolution Respirometer. Measurements taken before and after bed rest. |
Day -3 and Day 10. |
|
Secondary |
Changes in mitochondrial time to the permeability transition pore opening (marker of mitochondrial propensity to trigger apoptosis) in response to bed rest with and without ketone monoester (KET) supplementation. |
Determined spectrofluorometrically using the Calcium Green probe. Measurements taken before and after bed rest. |
Day -3 and Day 10. |
|
Secondary |
Changes in the phosphorylation status of anabolic signaling molecules modulating muscle protein synthesis (MPS) in response to bed rest with and without ketone monoester (KET) supplementation. |
Western blotting - membranes will be probed with phospho-specific antibodies against IRS-1S527/Thr446, AktSer473, mTORSer2448, 4E-BP1Thr37/46, rpS6Ser240/244, p70S6KThr389. Measurements taken before and after bed rest. |
Day -3 and Day 10. |
|
Secondary |
Changes in the phosphorylation status of catabolic signaling molecules modulating muscle protein breakdown (MPB) in response to bed rest with and without ketone monoester (KET) supplementation. |
Western blotting - membranes will be probed with phospho-specific antibodies against FoxO3aThr32, MuRF1, and MAFbx. Measurements taken before and after bed rest. |
Day -3 and Day 10. |
|
Secondary |
Blood beta-hydroxybutyrate concentrations (mmol/L) in response to bed rest with and without ketone monoester (KET) supplementation. |
Measurements taken at the start and end of bed rest. |
Day 5 and Day 10 |
|
Secondary |
Changes in subjective pain via visual analog scale in response to bed rest with and without ketone monoester (KET) supplementation. |
Throughout the 5 day bed rest period. |
Day 5-10. |
|
Secondary |
Changes in muscle area in response to bed rest with and without ketone monoester (KET) supplementation. |
Peripheral quantitative computed tomography (pQCT). Measurements taken before and after bed rest. |
Day -3 and Day 10. |
|
Secondary |
Changes in muscle density in response to bed rest with and without ketone monoester (KET) supplementation. |
Peripheral quantitative computed tomography (pQCT). Measurements taken before and after bed rest. |
Day -3 and Day 10. |
|
Secondary |
2H enrichments in body water before and during bed rest with and without ketone monoester (KET) supplementation. |
Throughout the baseline and bed rest period. |
Day -1 to Day 10. |
|
Secondary |
2H-alanine enrichment in venous blood before and during bed rest with and without ketone monoester (KET) supplementation. |
Throughout the baseline and bed rest period. |
Day -1 to Day 10. |
|
Secondary |
Changes in resting metabolic rate (RMR) in response to bed rest with and without ketone monoester (KET) supplementation. |
Measurements taken before and after bed rest. |
Day -3 and Day 10. |
|
Secondary |
Physical activity level via accelerometer before bed rest. |
Throughout the baseline period |
Day 0-4. |
|
Secondary |
Changes in sleep disturbance (numerical score) during bed rest with and without ketone monoester (KET) supplementation. |
Via Patient-Reported Outcomes Measurement Information System (PROMIS) Short form 8a. Measured throughout the 5 day bed rest period. |
Day 5-10. |
|
Secondary |
Changes in sleep quality (numerical score) during bed rest with and without ketone monoester (KET) supplementation. |
Via Pittsburgh Sleep Quality Index (PSQI). Measured throughout the 5 day bed rest period. |
Day 5-10. |
|
Secondary |
Average habitual dietary intake assessed using Keenoa for 3 days (a food tracker application). |
Dietary intake will be assessed for total energy (kcals) and macronutrient (protein, carbohydrate, and fat consumption; g) intake. |
Measured before bed rest. |
|
Secondary |
Changes in Thigh Absolute Synthetic Rate (ASR) in response to bed rest with and without ketone monoester (KET) supplementation. |
Changes in Thigh Absolute Synthetic Rate (ASR) will be calculated during baseline (day 0-5) and bed rest (day 5-10) phases. |
Day 0-5 and day 5-10 |
|
Secondary |
Changes in Thigh Absolute Protein Breakdown Rate (ABR) in response to bed rest with and without ketone monoester (KET) supplementation. |
Changes in Thigh Absolute Protein Breakdown Rate (ABR) will be calculated during baseline (day 0-5) and bed rest (day 5-10) phases. |
Day 0-5 and day 5-10 |
|