2019-11-23 New Scientist

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

Jessica Hamzelou

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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