Unsurprisingly there is resistance to this
work. Yet it is surely the clearest way
forward to producing human organs on demand that will be both quickly accepted
but also quickly integrated safely.
It may of course be only a step toward synthetic
organs using one’s own cells but it is likely a lot more. The fact remains that the process is quick
enough to operate effectively on demand in terms of disease management and the
pig is also far closer to us genetically than most understand.
Recent work argued forcefully for a one off for a
Pig Chimp/primate hybrid followed by continuous back breeding to produce
humanity. Thus the pig genetic
environment may be more welcoming than expected.
Regardless the present protocol for organ
replacement is impossible to sustain and must be replaced. This could be both viable and even seriously
superior to all possible alternatives.
Quest to grow human
organs inside pigs in Japan
By Rupert Wingfield-HayesBBC News, Ibaraki prefecture, Japan
2 January 2014 Last updated at 19:32 ET
I am standing in a fully functioning operating
theatre. A surgeon and team of specialists in green smocks are preparing to
operate. But I'm not in a hospital. I am on a farm deep in the Japanese
countryside. On the gurney about to undergo the knife is a six-month-old female
pig.
Standing over her, scalpel in hand, is Professor
Nagashima. He carefully cuts open her abdomen and pulls out her uterus. To me,
it looks more like intestines - but he assures me this is what a pig's uterus
looks like. Then with a syringe and a catheter,
he begins to inject 40 embryos into the uterus.
The unconscious pig is about to become a
surrogate mother - and the embryos she is now carrying are very special. They
are chimeric, that is, they carry genetic material from two different species.
In a nearby shed Prof Nagashima takes me to
see his most prized possessions. For this I have to change into full smock,
hat, boots and mask. It is not to protect me, it is to protect the occupants -
fully grown chimeric pigs.
'Switched off'
Halfway down the long white shed, I am
introduced to pig number 29 - a large, hairy male with jutting tusks. Number 29
is a white pig, but he is covered in coarse, black hair. More importantly,
inside, he has the pancreas of a black pig.
How is that possible? It starts off by making
what Prof Nagashima calls "a-pancreatic" embryos. Inside the white
pig embryo, the gene that carries the instructions for developing the animal's
pancreas has been "switched off".
The Japanese team then introduce stem cells
from a black pig into the embryo. What they have discovered is that as the pig
develops, it will be normal except for its pancreas, which will be genetically
a black pig's.
In a lab at Tokyo University Professor Hiro
Nakauchi is taking the next one, and this is even more astonishing.
Prof Nakauchi takes skin cells from an adult
brown rat. He then uses gene manipulation to change these adult skin cells into
what are called "iPS" cells. The amazing thing about induced
pluripotent stem cells is that they have many of the same characteristics as
embryonic stem cells. In other words, they can develop into any part of the
animal's body.
IPS cells were first created in 2006 by Japanese
medical researcher Dr Shinya Yamanaka. In 2012, he won the Nobel Prize for
his discovery.
In his lab, Prof Nakauchi has succeeded in
using these iPS cells to grow a brown rat pancreas inside a white mouse.
So why is all of this so important?
The
ultimate objective of this research is to get human organs to grow inside pigs.
By itself, that would be a massive breakthrough for science. But
what Prof Nakauchi is trying to achieve goes further. He is hoping to develop a
technique to take skin cells from a human adult and change them in to iPS
cells. Those iPS cells can then be injected into a pig embryo.
Island of Dr Moreau
The result, he hopes, will be a pig with a
human pancreas or kidney or liver, or maybe even a human heart. Not only that,
the organ would be genetically identical to the human from which the skin cells
were taken.
This is one of the holy grails of medical
research: the ability to reproduce a human organ that is genetically identical
to the person who needs it. It could mean an end to donor waiting lists, and an
end to problems of organ rejection.
But there are many potential obstacles ahead.
The first is that pigs and humans are only distantly related. It is one thing
to get a black pig pancreas to grow inside a white pig, quite another to get a
human pancreas to do the same. Prof Nakauchi is confident it can be done. He
thinks it will take at least five years, but admits it could take much longer.
The other problem is getting approval. In
Japan, it is illegal to make human-animal hybrids. Prof Nakauchi is pushing for
a change in the law. But if that does not happen, he may have to move his
research to America.
There are many here in Japan who oppose the
idea of human-animal hybrids. Animal rights activists object to the idea of
pigs, sheep or goats being used as human organ factories. Many more feel
uncomfortable about the idea of pig-human hybrids. It brings to mind HG Wells'
sci-fi classic, The Island of Dr Moreau.
Prof Nakauchi said his research is completely
different. The pigs would still be pigs; they would just be carrying some human
tissue inside them. He said there has always been resistance to new scientific
breakthroughs. He points to widespread objections to In Vitro Fertilisation
(IVF) when it was invented in Britain the 1970s. Today, IVF is used across the
world, and no one thinks it is strange or unethical.
Whatever the ethical debate, for the hundreds
of thousands of people around the world waiting for a new kidney or liver, the
prospect of being able to make one to order is an astonishing thought.
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