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Forearm Immobilization, Metabolic Health, and Nutrition

Not Applicable
Completed
Conditions
Healthy
Interventions
Behavioral: Forearm immobilization
Registration Number
NCT04626401
Lead Sponsor
University of Exeter
Brief Summary

The present study will investigate the impact of dietary branched chain amino acid restriction on muscle atrophy, insulin sensitivity and muscle protein synthesis following short-term forearm immobilization

Detailed Description

Twenty-four healthy young volunteers will undergo 2 days of forearm immobilization in combination with either a branched chain amino acid restricted diet or a control diet. Before and after immobilization, they will receive a stable isotope tracer infusion (5.5 h) combined with repeated blood and muscle sampling under insulin clamp conditions, in order to measure insulin sensitivity and muscle protein synthesis in the fasted and fed state.

Recruitment & Eligibility

Status
COMPLETED
Sex
All
Target Recruitment
24
Inclusion Criteria
  • Males and females 18-40 years of age
  • Body mass index between 18.5 and 30 kg/m2
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Exclusion Criteria
  • Smoking
  • Any diagnosed metabolic impairment (e.g. type 1 or 2 diabetes)
  • Any diagnosed cardiovascular disease
  • Hypertension (≥140 mmHg systolic and/or ≥90 mmHg diastolic)
  • Chronic use of any prescribed or over the counter pharmaceuticals (excluding oral contraceptives and contraceptive devices)
  • Regular use of nutritional supplements
  • Currently involved in a structured progressive resistance training programme (>3 times per week)
  • A personal or family history of thrombosis, epilepsy, seizures or schizophrenia
  • Any previous motor disorders or disorders in muscle and/or lipid metabolism
  • Known hypokalaemia
  • Presence of an ulcer in the stomach or gut and/or strong history of indigestion
  • Known severe kidney problems
  • Pregnant or breastfeeding
  • Unable to give consent
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Study & Design

Study Type
INTERVENTIONAL
Study Design
PARALLEL
Arm && Interventions
GroupInterventionDescription
Control diet during immobilisationForearm immobilizationA 2 day controlled dietary intervention.
Branched chain amino acid restricted diet during immobilisationForearm immobilizationA 2 day branched chain amino acid restricted dietary intervention.
Primary Outcome Measures
NameTimeMethod
Forearm glucose uptakeHyperinsulinaemic-euglycaemic clamps are performed before and immediately after 2 days of forearm immobilisation. Forearm glucose uptake is measured during the steady state period of the clamp.

Insulin sensitivity, measured as forearm glucose uptake, under hyperinsulinaemic-euglycaemic conditions

Secondary Outcome Measures
NameTimeMethod
Muscle protein synthesis ratesDuring 3 hours of hyperinsulinaemic-euglycaemic clamped conditions before and after 2 days of immobilisation

Muscle protein synthesis rates are measured using an intravenously infused stable isotope labelled amino acid tracer, combined with repeated blood and muscle tissue sampling.

Intramuscular BCAA concentrationBefore and after 3 hours of hyperinsulinaemic-euglycaemic clamped conditions

Intramuscular BCAA concentration measured using mass spectrometry

BCAA concentrations between forearm arterialized venous and deep venous bloodFasted and during the steady-state phase of the insulin clamp (i.e. last 30 minutes)

Arterialized venous-deep venous forearm balance of BCAA, in the fasted state and during a hyperinsulinaemic-euglycaemic clamp

Whole-body substrate oxidationHyperinsulinaemic-euglycaemic clamps are performed before and immediately after 2 days of forearm immobilisation. Whole-body substrate oxidation is measured before the commencement of, and during the steady state period of the clamp (last 30 minutes)

Whole-body substrate oxidation measured using indirect calorimetry

Trial Locations

Locations (1)

University of Exeter

🇬🇧

Exeter, Devon, United Kingdom

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