Muscle fibre size and myonuclear positioning in trained and aged humans
Experimental Physiology,
Journal Year:
2024,
Volume and Issue:
109(4), P. 549 - 561
Published: March 10, 2024
Abstract
Changes
in
myonuclear
architecture
and
positioning
are
associated
with
exercise
adaptations
ageing.
However,
data
on
the
number
of
myonuclei
following
inconsistent.
Additionally,
whether
domains
(MNDs;
i.e.,
theoretical
volume
cytoplasm
within
which
a
myonucleus
is
responsible
for
transcribing
DNA)
altered
age
remains
unclear.
The
aim
this
investigation
was
to
investigate
relationships
between
activity
status
positioning.
Vastus
lateralis
muscle
biopsies
from
younger
endurance‐trained
(YT)
older
(OT)
individuals
were
compared
age‐matched
untrained
counterparts
(YU
OU;
OU
samples
acquired
during
surgical
operation).
Serial,
optical
z
‐slices
throughout
isolated
fibres
analysed
give
three‐dimensional
coordinates
fibre
dimensions.
mean
cross‐sectional
area
(CSA)
33%–53%
smaller
other
groups.
nuclei
relative
CSA
90%
greater
YU
fibres.
scaling
MND
size
individuals.
arrangement,
contrast,
similar
across
Fibre
most
parameters
significantly
individuals,
but
not
trained
These
indicate
that
regular
endurance
lifespan
might
better
preserve
maintain
relationship
volumes.
Inactivity,
however,
result
reduced
parameters.
Language: Английский
Ageing leads to selective type II myofibre deterioration and denervation independent of reinnervative capacity in human skeletal muscle
Experimental Physiology,
Journal Year:
2024,
Volume and Issue:
110(2), P. 277 - 292
Published: Oct. 28, 2024
Age-related
loss
of
muscle
mass
and
function
is
underpinned
by
changes
at
the
myocellular
level.
However,
our
understanding
aged
phenotype
might
be
confounded
factors
secondary
to
ageing
per
se,
such
as
inactivity
adiposity.
Here,
using
healthy,
lean,
recreationally
active,
older
men,
we
investigated
impact
on
properties
in
skeletal
muscle.
Muscle
biopsies
were
obtained
from
young
men
(22
±
3
years,
n
=
10)
(69
11)
matched
for
health
status,
activity
level
body
index.
Immunofluorescence
was
used
assess
myofibre
composition,
morphology
(size
shape),
capillarization,
content
satellite
cells
myonuclei,
spatial
relationship
between
capillaries,
denervation
grouping.
Compared
with
muscle,
contained
53%
more
type
I
myofibres,
addition
smaller
(-32%)
misshapen
(3%)
II
myofibres
(P
<
0.05).
Aged
manifested
fewer
capillaries
(-29%)
(-38%)
surrounding
0.05);
however,
these
two
remained
intact.
The
proportion
denervated
∼2.6-fold
higher
old
than
had
grouped
(∼18-fold),
primarily
driven
increased
size
existing
groups
rather
group
frequency
displayed
selective
deterioration
alongside
These
data
are
key
cellular
basis
age-related
decline
reveal
a
pressing
need
fine-tune
strategies
preserve
innervation
status
populations.
Language: Английский