Dysfunction of Nutritive Blood Flow as a Determinant of Anabolic Resistance With Age; the Role of Amino Acids in Modulating Muscle Metabolism

Not Applicable

• Conditions: Old Age (Focus; Not a Recognized Condition)
• Interventions: Dietary Supplement: 4 x 3.75g Mixed EAA Pulses; Dietary Supplement: 15g EAA bolus; Dietary Supplement: 15g EAA Bolus supplemented with 3g Arginine

• Registration Number: NCT01735539
• Lead Sponsor: University of Nottingham

Brief Summary

The investigators plan to measure changes in muscle protein metabolism in response to feeding, comparing between a single large essential amino acid (EAA) feed (the normal building blocks of protein) and the provision of the same dose in 4 smaller feeds at 45min intervals. The investigators will perform this study in healthy older (65-75y) and younger (18-28) men. The investigators will also explore how feeding affects muscle blood flow as this is important in the delivery of the nutrients we eat to the muscle where they are used.

The investigators plan to supplement the feed with arginine, a safe and widely found non-essential amino acid, to explore if this can improve muscle blood flow.

Detailed Description

We will provide a 15g mixed essential amino acid feed or 4 x 3.75g.

There is sexual dimorphism thus initially we will just recruit males. Powering calculations dictate n=8 in each group.

We will use well established stable isotope tracer techniques (with 13C6 Phenylalanine) to measure muscle protein synthesis and breakdown by Gas Chromatography - combustion - isotope ratio mass spectroscopy.

We will measure leg blood flow by phase shift Doppler and muscle microvascular flow by contrast enhanced ultrasound.

Study Timeline

• Study Start: 2011-12
• Study First Submitted: 2012-11-22
• Study First Submitted QC: 2012-11-27
• Study First Posted: 2012-11-28
• Status Verified: 2014-01
• Primary Completion: 2014-01
• Study Completion: 2014-01
• Last Update Submitted: 2014-01-16
• Last Update Posted: 2014-01-17

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: Male
• Target Recruitment: 40

Inclusion Criteria

• age 65-75 or 18-28

Exclusion Criteria

• BMI >30
• Diabetes
• Beta blocker or steroid use
• Established cerebrovascular, peripheral vascular or ischaemic heart disease.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Old Pulse	4 x 3.75g Mixed EAA Pulses	4 x 3.75g Mixed EAA Pulses
Young Pulse	4 x 3.75g Mixed EAA Pulses	4 x 3.75g Mixed EAA Pulses
Old Bolus	15g EAA bolus	15g EAA bolus
Old Arginine	15g EAA Bolus supplemented with 3g Arginine	15g EAA Bolus supplemented with 3g Arginine
Young Bolus	15g EAA bolus	15g EAA bolus

Primary Outcome Measures

Name	Time	Method
Muscle Protein Synthesis (FSR, fractional synthetic rate, %/hr)	Across 6hr study	We measure FSR when fasted and again 0-90, 90-180 and 180-240 post feed.

Secondary Outcome Measures

Name	Time	Method
Muscle Protein Breakdown (MPB)	Across 6hr study	MBP is measured during fasting and 0-90, 90-180 and 180-240mins post feed.
Muscle Microvascular Blood flow	Across a 6hr study	We measure muscle microvascular flow using contrast enhanced ultrasound when fasted and again 0-90, 90-180 and 180-240 post feed.
Whole leg blood flow	Across a 6hr study	We measure common femoral blood flow by doppler ultrasound when fasted and again 0-90, 90-180 and 180-240 post feed.

Trial Locations

Locations (1)

University of Nottingham School of Graduate Entry Medicine and Health; 🇬🇧 Derby, United Kingdom