The Role of Muscle Protein Breakdown in the Regulation of Muscle Quality in Frail Elderly Individuals

The purpose of this study is to investigate mechanisms underlying the reduction in muscle quality (the ratio between muscle strength and muscle size) with aging, and to investigate how these factors are affected by strength training and protein supplementation. It is already established that muscle quality defined as the ratio between the strength and the size of a muscle is improved with strength training, even in frail elderly individuals. However, the relative contribution of factors such as activation level, fat infiltration, muscle architecture and single fiber function is unknown. The main focus of this study is to investigate the relationship between muscle quality and muscle protein breakdown, as insufficient degradation of proteins is hypothesized to negatively affect muscle quality.

Study Overview

• Status: Completed
• Conditions: Sarcopenia
• Intervention / Treatment: Other: Strength training; Dietary supplement: Protein supplementation

Detailed Description

Aging is associated with impaired skeletal muscle function. This is evident not only by a reduced capacity to generate force and power at the whole muscle level, but also by a decline in individual muscle fiber contraction velocity and force generation. Combined with muscle atrophy, these changes lead to reduced muscle strength and quality and loss off physical function with age. Clinically, muscle quality may be a better indicator of overall functional capacity than absolute muscle strength. Thus, identifying the mechanisms underlying the age-related loss of muscle quality is of high relevance for the prevention of functional impairment with aging. The explanation for the loss of muscle quality with aging seems to be multifactorial, with alterations in voluntary muscle activation, muscle architecture, fat infiltration and impaired contractile properties of single muscle fibers being likely contributors. Single fiber specific force seems to be related to myosin heavy chain (MHC) content, which is thought to reflect the number of available cross-bridges. The reduction of single fiber specific force with aging may thus be a consequence of reduced synthesis of MHC and/or increased concentration of non-contractile tissue (e.g. intramyocellular lipids).

Some studies in mice also indicate attenuated activity in some of the pathways responsible for degradation of muscle proteins with aging (especially autophagy). As a result, damaged proteins and organelles are not removed as effectively as they should, which could ultimately compromise the muscle's ability to produce force. In addition, reduced efficiency of mitophagy and lipophagy (two specific forms of autophagy), may indirectly affect single fiber specific force, through oxidative damage by reactive oxygen species (ROS) and increased levels of intramyocellular lipids, respectively. Although animal studies indicate attenuated autophagic function, exercise seems to restore the activity in this pathway. Whether this also is the case in humans is unknown. Thus, the purpose of this study is to investigate how the different factors contributing to reduced muscle quality in frail elderly individuals, with emphasis on the relationship between muscle quality and autophagy, may be counteracted by a specific strength training program targeting muscle quality and muscle mass.

In this randomized controlled trial the investigators will aim to recruit frail elderly individuals, as muscle quality is shown to be low in this population. As a consequence, the potential for improved muscle quality is expected to be large. Subjects will be randomized to two groups; one group performing strength training twice a week for 10 weeks in addition to receiving daily protein supplementation. The other group will only receive the protein supplement. Several tests will be performed before and after the intervention period, including a test day where a biopsy is obtained both at rest, and 2.5 hours following strength training + protein supplementation or protein supplementation only. This will provide information about the regulation of muscle protein breakdown in a resting state, following protein intake and following strength training in combination with protein intake. As this will be done both before and after the training period, it will also provide information on how long-term strength training affects the activity in these systems.

• Study Type: Interventional
• Enrollment (Actual): 34
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Norway
  • Oslo, Norway, 0863
    • Norwegian School of Sport Sciences

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 65 years and older (OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age > 65
• Frail or pre-frail according to the Fried Frailty Criteria or Short Physical Performance Battery (SPPB) score <6.
• Mini Mental State Examination score > 18

Exclusion Criteria:

• Diseases or injuries contraindicating participation
• Lactose intolerance
• Allergy to milk
• Allergy towards local anesthetics (xylocain)
• Use of anticoagulants that cannot be discontinued prior to the muscle biopsy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: RANDOMIZED
• Interventional Model: PARALLEL
• Masking: SINGLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Strength training + protein supplement; Two sessions of strength training each week in addition to daily protein supplementation for 10 weeks.	Other: Strength training; Heavy load strength training performed twice a week for 10 weeks.; Other Names: Resistance training; Dietary supplement: Protein supplementation; Dietary protein supplement (protein-enriched milk with 0,2 % fat). 0,33 l each day for 10 weeks.
EXPERIMENTAL: Protein supplement; Daily protein supplementation for 10 weeks.	Dietary supplement: Protein supplementation; Dietary protein supplement (protein-enriched milk with 0,2 % fat). 0,33 l each day for 10 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Single fiber specific force	A measure of muscle quality at the single fiber level. Biopsies obtained from m. Vastus Lateralis	Change from baseline at 10 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Lean mass	Measured by a Dual-energy X-ray absorptiometry (DXA) scan	Change from baseline at 10 weeks
Fat mass	Measured by a Dual-energy X-ray absorptiometry (DXA) scan	Change from baseline at 10 weeks
Bone mineral density	Measured by a Dual-energy X-ray absorptiometry (DXA) scan	Change from baseline at 10 weeks
Muscle strength of m. quadriceps	Maximal isometric and dynamic muscle strength of m. quadriceps	Change from baseline at 10 weeks
Muscle size of m. quadriceps	Cross-sectional area of m. quadriceps measured by a Computed Tomography scan	Change from baseline at 10 weeks
Fat infiltration of m. quadriceps	Fat infiltration of m. quadriceps measured by a Computed Tomography scan	Change from baseline at 10 weeks
Muscle activation	Voluntary activation level during a maximal isometric knee extension using the interpolated twitch technique	Change from baseline at 10 weeks
Fractional Breakdown Rate	Measurement of fractional breakdown rate by the use of orally provided Deuterium Oxide, biopsies and blood samples	Measured over the last 14 days of the intervention period
m. Vastus Lateralis thickness	Measured by ultrasound	Change from baseline at 10 weeks
Chair stand performance	Time (sec) to stand up from a chair five times	Change from baseline at 10 weeks
Habitual gait velocity	Time (sec) to walk 6 meters at habitual gait velocity	Change from baseline at 10 weeks
Maximal gait velocity	Time (sec) to walk 6 meters as fast as possible	Change from baseline at 10 weeks
Level/cellular location of Microtubule-associated protein 1A/1B-light chain 3 (LC3)	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
Level/cellular location of p62/Sequestosome-1	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
Level/cellular location of Lysosome-associated membrane glycoprotein 2 (LAMP2)	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
Level/cellular location of forkhead box O3 (FOXO3a)	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
Phosphorylation status and total level of ribosomal protein S6 kinase beta-1(P70S6K)	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
Phosphorylation status and total level of eukaryotic elongation factor 2 (eEF-2)	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
Phosphorylation status and total level of eukaryotic translation initiation factor 4E-binding protein 1 (4EBP-1)	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
Level/cellular location of muscle RING-finger protein-1 (Murf-1)	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
Level/cellular location of ubiquitin (Ub)	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
Blood serum glucose	Fasted	Change from baseline at 10 weeks
Blood serum insulin	Fasted	Change from baseline at 10 weeks
Blood plasma Hemoglobin A1c (HbA1c)	Fasted	Change from baseline at 10 weeks
Blood serum Triglycerides	Fasted	Change from baseline at 10 weeks
Blood serum High-density lipoproteins (HDL)	Fasted	Change from baseline at 10 weeks
Blood serum Low-density lipoproteins (LDL)	Fasted	Change from baseline at 10 weeks
Blood serum C-reactive protein (CRP)	Fasted	Change from baseline at 10 weeks
forkhead box protein O3 (FOXO3A) mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
forkhead box protein O1 (FOXO1) mRNA mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
hepatocyte growth factor (HGF) mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
insulin-like growth factor I (IGF1) mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
myostatin (MSTN) mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
E3 ubiquitin-protein ligase TRIM63 (TRIM63) mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
p62/Sequestosome-1 mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
muscle RING-finger protein-1 (Murf-1) protein 1 (4EBP-1) mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
Atrogin1 mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
Microtubule-associated protein 1A/1B-light chain 3 (LC3) mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
BCL2/adenovirus E1B interacting protein 3 (BNIP3) mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
PTEN-induced putative kinase 1 (PINK1) mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
TNF receptor associated factor 6 (TRAF6) mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
transcription factor EB (Tfeb) mRNA	Biopsies from m. Vastus Lateralis analyzed by western blot	Before and 2.5 hours after acute training session both at baseline and after 10 weeks
Intramyocellular lipids	Oil-Red-O staining of muscle sections. Biopsy from m. Vastus Lateralis analyzed by immunohistochemistry	Change from baseline at 10 weeks
Muscle fiber type distribution	Biopsy from m. Vastus Lateralis analyzed by immunohistochemistry	Change from baseline at 10 weeks
Muscle fiber cross-sectional area	Biopsy from m. Vastus Lateralis analyzed by immunohistochemistry	Change from baseline at 10 weeks
Muscle satellite cells	Biopsy from m. Vastus Lateralis analyzed by immunohistochemistry	Change from baseline at 10 weeks
Myonuclei	Biopsy from m. Vastus Lateralis analyzed by immunohistochemistry	Change from baseline at 10 weeks
Myonuclei number	Biopsy from m. Vastus Lateralis analyzed by confocal microscopy	Change from baseline at 10 weeks
Myonuclei location	Biopsy from m. Vastus Lateralis analyzed by confocal microscopy	Change from baseline at 10 weeks
Amount of mitochondria	Biopsy from m. Vastus Lateralis analyzed by confocal microscopy	Change from baseline at 10 weeks
Location of mitochondria	Biopsy from m. Vastus Lateralis analyzed by confocal microscopy	Change from baseline at 10 weeks

Collaborators and Investigators

• Sponsor: Truls Raastad
• Collaborators: University of Copenhagen; University of Padova; Tine

Study record dates

Study Major Dates

• Study Start (ACTUAL): September 1, 2016
• Primary Completion (ACTUAL): December 20, 2017
• Study Completion (ACTUAL): March 1, 2018

Study Registration Dates

• First Submitted: May 5, 2017
• First Submitted That Met QC Criteria: October 25, 2017
• First Posted (ACTUAL): October 31, 2017

Study Record Updates

• Last Update Posted (ACTUAL): April 11, 2018
• Last Update Submitted That Met QC Criteria: April 10, 2018
• Last Verified: April 1, 2018

More Information

Terms related to this study

• Keywords: Sarcopenia; Frailty; Autophagy; Strength training
• Additional Relevant MeSH Terms: Nervous System Diseases; Neurologic Manifestations; Neuromuscular Manifestations; Pathological Conditions, Anatomical; Muscular Atrophy; Atrophy; Sarcopenia
• Other Study ID Numbers: STAS

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No