(C. Jardin) #1

10 | New Scientist | 1 February 2020

THE race to create pigs with organs
that are suitable for transplanting
into people is hotting up. At least
three teams have added human
genes to pigs to try to prevent
donor organs from being rejected
by a recipient’s immune system.
The research could solve two
problems. The first is a shortage of
human donor organs. The second
is that people who get transplants
need to take medicines for the rest
of their lives to suppress their
immune system and avoid the
new organ being rejected.
Different research teams are
trying to tackle this by adding
human genes to pigs, in an effort
to make their organs suitable for
humans, and potentially less likely
to be rejected by the recipient’s
immune system too.
Lijin Zou at the First Affiliated
Hospital of Nanchang University
in China and his colleagues have
created pigs into which they added
eight human genes that reduce
the chance of a donor organ being
rejected, and removed three key
pig genes that trigger organ
rejection. The group then
transplanted skin from these

pigs to monkeys. The skin graft
survived for up to 25 days without
the monkeys needing any
immune system suppressing
drugs (bioRxiv, doi.org/dkkn).
“So far, it is the best result, at
least from the English literature,”
says Zou. His team is preparing to
start human trials of the pig skin
as a temporary cover for extensive
burns. These are usually covered
with skin from dead human

donors while new skin grows.
Zou says he would “expect even
better” results in humans.
Interest in this kind of approach
has surged in the past decade as
advances such as CRISPR gene
editing have made it feasible
to make extensive changes
to the genomes of animals.
In December, Luhan Yang at
biotech firms Qihan Bio in China
and eGenesis in the US reported
that her team had created pigs
with nine added human genes
and dozens of deleted pig genes.
In addition to deleting the same

three genes knocked out by Zou’s
team, Yang’s team also inactivated
dozens of pig viral genes known as
porcine endogenous retroviruses,
or PERVs (bioRxiv, doi.org/ggf4s2).
“It is a major technological
achievement,” says David Cooper
of the University of Alabama
at Birmingham, a former
transplant surgeon who works
on transplanting pig organs.
But regulators will want to know
whether all of these genetic
changes are necessary, he says.
Cooper is working with US
biotech company Revivicor, which
has added six human genes to
pigs, as well as deleting the same
three pig genes as the other teams.
“I believe that any of these pigs
will be suitable for a clinical trial
[in humans], but we have to
persuade the regulatory
authorities first,” he says.
If PERVs start infecting human
cells after a transplant, there is a
risk they might cause cancer years
later, says John Coffin at Tufts
University School of Medicine
in Boston. But this is still better
than the outcomes if people
don’t get a transplant, he says. ❚

“Body modifications are
often associated with social
maturation, like puberty
and rites of passage”

Organ transplants

Michael Le Page



O^ R





Ancient humans

People have been
getting piercings
for a ver y long time

A YOUNG man who lived over
12,000 years ago in east Africa
probably had facial piercings. The
finding suggests people have been
wearing facial piercings in Africa
since deep in prehistory.
“We’re potentially opening
a window into the life of this
individual,” says John Willman
at the University of Coimbra in
Portugal. Body modifications
“are often associated with social

maturation, things like puberty and
rites of passage”, he says.
He has been studying the skull
of a young adult male known as
Olduvai Hominid 1, or OH1. It was
discovered in 1913 in Olduvai
gorge in Tanzania. In 1993,
researchers noted unusual wear
on OH1’s teeth. They thought this
was due to chewing tough plants.
“I took one look at it and said ‘no’,”
says Willman, who has studied the
jaws of First Peoples in Canada
who had facial piercings. So he and
his colleagues re-examined and
measured OH1’s teeth and jawbone.
They found that the incisor teeth

were worn at the front. “It looks
almost like somebody took the
front end off these teeth with an
ice cream scoop,” he says.
Towards the back of the mouth,
the premolars and molars were also
worn. “All the curvature you can feel
when you run your tongue over your
cheek teeth is virtually gone,” says
Willman. The team believes these
wear patterns mean OH1 had three
facial piercings: a “labret” through

his lower lip, and one in each cheek
(American Journal of Physical
Anthropology, doi.org/dkhm).
Because the piercings haven’t been
preserved, we don’t know what
they were made of or looked like.
OH1 lived between 12,000 and
20,000 years ago, making him the
oldest known example of facial
piercings in Africa and the second
oldest in the world. Previously, most
evidence for piercings came from
humans who were alive in the last
5000 years. The oldest instance
of cheek piercings on record is in
central Europe 25,000 years ago. ❚
Michael Marshall

Human genes given to pigs to create

rejection-proof skin for transplants

Genetically engineered
pigs could provide organs
suitable for transplant
Free download pdf