The Effects of Varying Protein Intakes on Muscle Protein Synthesis During Injury-Mediated Muscle Disuse
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 发起方
- 入组人数
- 28
- 试验地点
- 1
- 主要终点
- Rates of postabsorptive and postprandial muscle protein synthesis assessed using 2H5-Phenylalanine stable isotope methodologies.
研究概览
简要总结
Individuals who sustain musculoskeletal injuries (MSKI) can experience a rapid loss of muscle mass due to declines in muscle loading and activation that occur post-injury (i.e., disuse atrophy). Loss of muscle under these conditions is attributed to a persistent negative net muscle protein balance (muscle protein synthesis [MPS] < muscle protein breakdown) that results, in part, from declines in postprandial MPS (i.e., anabolic resistance). Nutritional interventions that enhance postprandial MPS may be used to overcome disuse-induced anabolic resistance and preserve muscle mass to accelerate recovery and improve recovery outcomes. While supplemental protein has been explored as a potential countermeasure to disuse-induce anabolic resistance, the observed efficacy of such interventions has been mixed. Equivocal findings across studies may be attributed, in part, to an insufficient understanding of what constitutes an effective protein-based intervention. Importantly, no study to date has determined an optimal protein dose for overcoming disuse-induce anabolic resistance, or if there is a threshold for maximally stimulating postprandial MPS under disuse conditions. Therefore, the objective of this work is to determine rates of MPS at rest and in response to standard (20 g) or high (40 g) doses of whey protein during knee immobilization (DISUSE) compared with standard activity (ACTIVE)
详细描述
Healthy, recreationally active men and women will complete this randomized, double-blind, parallel study. Muscle disuse will be implemented for five days using a unilateral leg immobilization model with one leg assigned to immobilization (DISUSE) and the contralateral leg used as a control (ACTIVE). Immobilization will be implemented with a rigid knee brace fixed at ~60° of flexion and participants will ambulate using crutches. Diets will be standardized during the immobilization phase. Participants will complete a protein feeding study at the end of immobilization consisting of primed, continuous stable isotope infusions, serial blood draws, and muscle biopsies. MPS will be assessed in both the DISUSE and ACTIVE legs in response to standard (20 g) or high (40 g) doses of whey protein. Findings from this work will directly inform the development of targeted nutritional countermeasures for overcoming disuse-induced anabolic resistance and preserving muscle mass after MSKI to optimize physical performance recovery.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Basic Science
- 盲法
- Double (Participant, Investigator)
入排标准
- 年龄范围
- 17 Years 至 39 Years（Child, Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Men and women aged 18-39 years (17-39 years if military personnel)
- •Body mass index (BMI) between 18.5-32 kg/m2
- •Routinely participate in aerobic and/or resistance exercise at least 2 days per week.
- •Willing to refrain from alcohol, smoking, smokeless nicotine products (includes e-cigarettes, vaping, chewing tobacco), and dietary supplements (i.e., vitamin D, probiotics) 24 hours before and during immobilization and final testing day.
- •Willing to only consume caffeine products provided by study staff during the study.
- •Supervisor approval for federal civilian employees and non-SRV active-duty military personnel stationed at NSSC.
- •Biological females must have normal menstrual cycles between 26-32 days in duration; 5 menstrual cycles within the past 6 months; or on continuous hormonal contraception (i.e., IUD or oral contraceptives without placebo).
排除标准
- •Musculoskeletal injuries that may interfere with the safe use of crutches.
- •Personal or family history of thrombosis, or prior diagnosis of deep vein thrombosis (DVT) or pulmonary embolism (PE).
- •Metabolic or cardiovascular abnormalities, gastrointestinal disorders, neuromuscular disorders, lower-limb amputation, or muscle/bone wasting disorders (e.g., diabetes, cardiovascular disease, Crohn's disease, etc.).
- •Taking medication that affects macronutrient utilization (i.e., statins, corticosteroids, weight loss medications such as Ozempic, etc.).
- •Significantly abnormal blood clotting as determined by USARIEM Office of Medical Oversight (OMSO) or home duty station medical support (HMS).
- •Allergy to lidocaine (or similar local anesthetic).
- •Present condition of alcoholism, anabolic steroid use, or other substance abuse issues as determined by OMSO or HMS.
- •Blood donation within 8-wk of beginning the study.
- •Pregnant, trying to become pregnant, and/or breastfeeding (results of urine pregnancy test and self-report for breastfeeding will be obtained before body composition testing).
- •Unwilling or unable to consume study diets or foods provided due to personal preference and/or food allergies.
- •Unwilling or unable to adhere to study physical restrictions (i.e., no structured physical activity or recreational activity beyond activities of daily living) 24 hours before and during immobilization, and the final testing day.
- •Unwilling or unable to keep the knee brace on and walk with crutches during the immobilization phase.
研究组 & 干预措施
Standard Protein Dose
Participants will consume 20 g of whey protein after 5 days of muscle disuse
干预措施: 20 grams protein (Dietary Supplement)
High Protein Dose
Participants will consume 40 g of whey protein after 5 days of muscle disuse
干预措施: 40 grams protein (Dietary Supplement)
结局指标
主要结局
Rates of postabsorptive and postprandial muscle protein synthesis assessed using 2H5-Phenylalanine stable isotope methodologies.
时间窗: After 5 days of muscle disuse
Postabsorptive and postprandial muscle protein synthesis in response to 20 or 40 g of whey protein determined using 2H5-Phenylalanine stable isotope methodologies and expressed as fractional synthetic rate (FSR).
次要结局
未报告次要终点