Annual Report 2015–2016

CASE STUDY
The team studied diaphragms of preterm lambs to
determine how fetal exposure to common events such
as maternal steroids or infection of the womb affects
diaphragm development in an unborn baby.
Through this research, Professor Pillow and her team
discovered that the preterm diaphragm is weaker
than the diaphragm of babies born after a normal and
complete gestation. This may be due to increased
breakdown of the muscle protein and increased
susceptibility to damage from oxygen free radicals.
Respiratory disease
is the leading cause
of mortality in
preterm infants
Professor Pillow explained that the diaphragm is further
impaired when the fetus is exposed to infection in the
womb or high-dose maternal steroids.
“Preterm babies are more likely to be exposed to
infection and other agents that interfere with diaphragm
development, making breathing efforts weaker after birth
and potentially leading to respiratory failure.
“Our studies suggested that the timing of the exposure
to infection in the womb is critical; exposure early in
gestation results in weaker diaphragms than those
exposed closer to term gestation.
“Fetal exposure to maternal steroids, which are often
used to improve the lung development of fetuses that are
likely to be born preterm, may also be harmful to longterm
diaphragm development when administered at high
doses,” Professor Pillow explained.
These findings have the potential to benefit preterm
infants at risk of acute and chronic respiratory disease.
The team has opened a new area for focus in protecting
and treating premature babies at risk of respiratory
failure.
“As the diaphragm is the main muscle driving our ability
to breathe independently, impaired diaphragm function
decreases our ability to breathe without mechanical
assistance. Furthermore, the use of mechanical
ventilation to support the breathing of infants who
cannot sustain independent breathing may further impair
the function of the diaphragm. Thus, adverse exposures
such as womb infections may initiate a vicious cycle
of impaired diaphragm function that may make it very
difficult to wean the infants off mechanical ventilation so
that they can breathe on their own without support.
“Preventing diaphragm dysfunction through ventilatory
or pharmacological treatments will provide a new
opportunity to protect the preterm infant from developing
chronic respiratory disease.
“These findings will be of interest to clinicians and
nurses treating preterm infants, and to the parents
of the infants at risk for this disorder,” Professor
Pillow concluded.
PART 6 operating environment
“We were able to show that this weakness in the
diaphragm after fetal exposure to a womb infection
could be partly reduced by preventing the inflammatory
response through blocking a key component in the
pathway called interleukin,” Professor Pillow said.
Annual Report of the National Health and Medical Research Council 2015–2016
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