2019-11-23 New Scientist

(Chris Devlin) #1

16 | New Scientist | 23 November 2019


WOMEN with polycystic ovary
syndrome often struggle to
maintain a steady weight. A nasal
spray of insulin might help such
women burn calories, according
to preliminary research in sheep,
which can show many of the
same symptoms of PCOS. A trial
in women with the condition is
now being planned.
Around 7 to 8 per cent of women
have polycystic ovary syndrome,
which affects the way ovaries
work. Women with PCOS often
have irregular periods and can
find it difficult to become
pregnant. But PCOS also appears
to put women at risk of obesity
and diabetes. In the US, around
three-quarters of women with
PCOS are also obese.
Colin Duncan at the University
of Edinburgh, UK, says that
most of his patients can have
restored ovulation with the right
treatment, but treating obesity
is much harder. That is because
women with PCOS find it more
difficult to lose weight.
A study published in the 1990s
suggested that this is because
women with PCOS are less able

to burn calories. After most people
eat a meal, their fat tissue starts to
burn through calories, releasing
heat, but this is reduced by around
25 per cent in women with PCOS.
This means that a woman
with PCOS would have to eat
around 4 per cent less, or exercise
around 20 per cent more, than
another woman of a similar
height and weight who doesn’t
have the disorder, just to maintain

a steady weight, says Duncan.
To find out if they could
discover a potential treatment,
Duncan and his colleagues
turned to sheep. When Scottish
greyface ewes are injected with
male levels of testosterone, says
Duncan, they show the symptoms
of PCOS: they stop ovulating,
develop polycystic ovaries and
gain weight.
When Duncan’s team sprayed
insulin up the noses of 12 of the
sheep with PCOS-like symptoms,
the sheep’s fat tissue appeared to
burn more calories. The group

hasn’t yet studied the animals for
long enough to see whether they
lose weight.
“This was a short-term proof-
of-concept study,” says Duncan,
who presented the findings at the
Society for Endocrinology BES
annual meeting in Brighton, UK,
on 12 November.
Duncan is currently applying
for funding to trial the same
approach in women with PCOS.
Because insulin has been
associated with satiety, Duncan
hopes the women that try it will
benefit from both effects. “Maybe
squirting insulin up your nose
gets you two benefits: it burns
off calories and makes you not
want to eat any more,” he says.
Hormone production in
sheep isn’t the same as that
of humans, says Lina Schiffer
at the University of Birmingham,
UK, who chaired the session at
which Duncan presented his
results. “[Duncan’s] work has
established the rationale and
applicability of this in sheep with
great success,” she says. “We now
need to translate this into the
human setting.” ❚

“A layer of plastic crust
forms when waste debris
is worn down by waves
rubbing it over rocks”

Health

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News


Insulin (pictured) could
alleviate a symptom of
polycystic ovary syndrome

Environment

Odd forms of plastic
pollution turn up in
the Mediterranean

TWO unusual types of marine plastic
debris have been documented in the
Mediterranean for the first time, on
the Italian island of Giglio off the
coast of Tuscany.
Plasticrust, as the name suggests,
is a layer of plastic crust. It forms on
rocks when plastic in the ocean is
mechanically worn down by waves
rubbing it over outcrops, leading to
small particles getting trapped on
the solid surface. Prior to being

spotted in Italy, plasticrusts have
also been found recently on the
Portuguese island of Madeira. The
other type of debris is pyroplastic,
burned pieces of plastic that are
hard to distinguish from stones.
These have also been found before
in Cornwall and Devon in the UK.
Sonja Ehlers at Germany’s
Federal Institute of Hydrology and
independent researcher Julius Ellrich
say their findings on Giglio suggest
these types of plastic pollution are
more widespread than thought.
Ehlers and Ellrich surveyed
several sites on Giglio last month.
They discovered blue layers of

plasticrusts on rocks that are
submerged at high tide, and
grey-blue stone-like blobs of
pyroplastic on a beach. Analysis
using spectroscopy showed the
plasticrust was polyethylene, the
most common plastic we produce.
The pyroplastic was polyethylene
terephthalate, used to make drink
bottles (bioRxiv, doi.org/dd8k).
The culprit for the pyroplastic
may have been a beach campfire,

says Ehlers, judging from burnt
charcoal discovered nearby and
the number of blue plastic bottles
she found on Giglio. We should
be concerned, says Ehlers. “It
shows how plastic debris is
changing the landscape.”
We don’t know for sure
whether animals are eating these
plastics, but it seems likely. Snails
were found on the plasticrust in
Madeira and marbled rock crabs
(Pachygrapsus marmoratus) on
the plasticrust in Giglio. “This
might be a way the plastic enters
the food chain,” says Ehlers. ❚
Adam Vaughan

An insulin nasal spray could help


with polycystic ovary syndrome

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