The effect of Neuromuscular Electrical Stimulation on post-prandial muscle protein accretion in healthy elderly men

With human aging there is a gradual but progressive decline in skeletal muscle
mass, termed sarcopenia.. While the underlying cause of sarcopenia is likely to
be multifaceted, a primary factor is that elderly individuals frequently
experience short periods of muscle disuse following limb immobilization or
bed-rest (due to injury or illness) causing rapid muscle loss. Elderly
individuals seem to be more susceptible to muscle disuse atrophy and are less
likely to fully regain their muscle tissue during subsequent rehabilitation
when compared to the young. Muscle loss during a period of disuse is attributed
to an impairment of muscle protein synthesis rates. Accordingly, feasible
strategies for maintaining muscle protein synthesis rates in elderly
individuals, and thus having the potential to attenuate the loss of muscle mass
during disuse need to be pursued. Local neuromuscular electrical stimulation
(NMES) offers such a potential strategy but, as yet, remains relatively
unexplored.

The aim of this study is to investigate the effect of a single bout of NMES on
muscle protein synthesis rates in healthy elderly males.

10 healthy, elderly men will consume a 20g bolus of intrinsically
L[13C]phenylalanine labelled casein protein immediately following 70 min of
one-legged NMES. Regular blood samples will be collected and muscle biopsies
will be obtained immediately prior to protein ingestion and 240 min after
ingestion from both legs to determine de novo muscle protein synthesis rates
from both the stimulated (STIM) and un-stimulated control (CON) legs.

Consumption of a 20g bolus of intrinsically L[13C]phenylalanine labelled casein
protein and 70 min of one-legged NMES.

The risks involved in participating in this experiment are minimal. Insertion
of the catheters in a vein is comparable to a normal blood draw and the only
risk is a small local hematoma. This is the same for the muscle biopsies. The
incision made for obtaining the muscle biopsy will be done by an experienced
physician, following local anesthetics of the skin and muscle fascia, and will
heal completely. The test beverages contain intrinsically labeled dietary
protein which is safe for human consumption and has been used in previous
studies (MEC 11-3-057 and MEC 11-3-088). NMES carries no potential risks other
than slight skin irritation from the surface electrodes.