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Influence of Reduced Daily Step Count and Anabolic Interventions on Muscle Protein Metabolism in Older Persons

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ClinicalTrials.gov Identifier: NCT02347137
Recruitment Status : Completed
First Posted : January 27, 2015
Last Update Posted : January 27, 2015
Sponsor:
Information provided by (Responsible Party):
McMaster University

Brief Summary:
As the loss of muscle mass with aging is associated with a dysregulation of muscle protein synthesis (MPS) that is generally characterized by an 'anabolic resistance' to nutrients, the primary outcome of the trial is to investigate the effect of a mixed macronutrient beverage on post-prandial myofibrillar MPS. However, the 'anabolic resistance' of aging may be predominantly influenced by the contractile activity of skeletal muscle; for example, the investigators have demonstrated that 2 weeks of reduced habitual activity (i.e. daily step count) induces anabolic resistance in otherwise healthy older adults. In contrast, resistance exercise is well-known to enhance muscle mass and can increase the sensitivity of skeletal muscle to dietary amino acids. Therefore, all participants will undergo a 2-week reduced step count intervention combined with a unilateral leg resistance exercise protocol to induce an 'unhealthy' or 'anabolically resistant' leg and a relatively 'healthy' or 'anabolically sensitive' leg, respectively; this within subject model will be utilized to investigate the effect of the mixed macronutrient beverage in both relatively 'healthy' and 'unhealthy' older muscle. The investigators will also measure changes in muscle mass, muscle function, and cardiovascular health of both legs before and after the 2-week intervention to determine the effect of reduced activity and the protective effect of minimal, low-intensity exercise on these outcomes.

Condition or disease Intervention/treatment Phase
Older Adults Muscle Protein Synthetic Response to Protein Reduced Physical Activity Other: step-reduction Other: step-reduction plus resistance exercise Not Applicable

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 30 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: Efficacy of Isolated Whey and Micellar Whey Protein (+/-Citrulline) to Stimulate Protein Synthesis in 'Healthy' and 'Anabolically Resistant' Elderly Muscle
Study Start Date : July 2012
Actual Primary Completion Date : May 2013
Actual Study Completion Date : May 2013

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Active Comparator: Isolated Whey Protein
20 g isolated whey protein + 15 g non-essential amino acids
Other: step-reduction
reduce daily physical activity to less than 1500 steps per day

Other: step-reduction plus resistance exercise
reduce physical activity to less than 1500 steps per day with thrice weekly low-load, high effort resistance exercise

Experimental: Micellar Whey Protein
20 g micellar whey protein + 15 g non-essential amino acids
Other: step-reduction
reduce daily physical activity to less than 1500 steps per day

Other: step-reduction plus resistance exercise
reduce physical activity to less than 1500 steps per day with thrice weekly low-load, high effort resistance exercise

Experimental: Micellar Whey Protein + Citrulline
20 g micellar whey protein + 5 g citrulline
Other: step-reduction
reduce daily physical activity to less than 1500 steps per day

Other: step-reduction plus resistance exercise
reduce physical activity to less than 1500 steps per day with thrice weekly low-load, high effort resistance exercise




Primary Outcome Measures :
  1. Myofibrillar fractional synthetic rate will be measured using 13C6 ring phenylalanine [ Time Frame: 7 hours ]
    analysis


Secondary Outcome Measures :
  1. body composition (lean body mass, fat mass, leg lean mass, leg fat mass) will be measured using dual energy xray absorptiometry [ Time Frame: 14 days ]
    analysis

  2. leg muscle strength (leg press and leg extension 1 repetition maximum [1-RM], peak knee extensor torque) will be measured using a dynamometer [ Time Frame: 14 days ]
    analysis

  3. vascular function (femoral blood flow, femoral artery diameter, leg pulse) will be measured using doppler ultrasound [ Time Frame: 14 days ]
    analysis



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Ages Eligible for Study:   65 Years to 80 Years   (Older Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Non-smoker

Exclusion Criteria:

  • Health problems such as: heart disease, rheumatoid arthritis, diabetes, poor lung function, uncontrolled hypertension, or any health conditions that might put the participant at risk for this study
  • Failed clearance for exercise participation by the participants family physician/medical doctor
  • Failed an exercise strength test.
  • Regular consumption of any analgesic or anti-inflammatory drug(s), prescription or non-prescription, chronically will be excluded.
  • Taking any medications known to affect protein metabolism (i.e. corticosteroids, non-steroidal anti-inflammatories, or prescription strength acne medications).
  • Factors that may exclude a participant from an MRI scan (i.e. various implants, metal in the eyes etc)
  • Participants who complete fewer than 5000 steps per day (as assessed by pedometer prior to the study).

Information from the National Library of Medicine

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): NCT02347137


Locations
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Canada, Ontario
Exercise Metabolism Research Laboratory, McMaster Univeristy
Hamilton, Ontario, Canada, L8S 4K1
Sponsors and Collaborators
McMaster University
Publications:
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Responsible Party: McMaster University
ClinicalTrials.gov Identifier: NCT02347137    
Other Study ID Numbers: 11-267
First Posted: January 27, 2015    Key Record Dates
Last Update Posted: January 27, 2015
Last Verified: January 2015