Humans, animals and organs

1
Humans, animals and organs

• Presented by
• Lauren Higdon
• Ji Nin Loh

www.graphicwitness.org/_coe/prntlist.htm
2
The Question

• What is xenotransplantation?
• Xenotransplantation is transplanting animal
  organs into humans
• What are transgenic animals?
• Transgenic animals, also known as chimeras, are
  animals that contain genes from more than one
  species.

3
Where did they come from?

• The first cells were grown outside of a body in
  culture in 1885.
• The first transgenic mammals were born in 1976
  (Dixon).
• Now, Britain creates 60,000 every year (Dixon).

4
What else has been done?

• Human embryonic stem cells were used to grow
  kidneys in 2002.
• After being transplanted into mice, the kidneys
  functioned perfectly well.
• Stem cells lack the antigens that adult cells
  contain, reducing the risk of rejection.

5
Where did the pigs come in?

• A miniature pig was successfully cloned.
• The original pig did not have either half of a
  gene that provokes immune rejection of
  transplanted organs.
• Because the baby pig was a perfect clone, all of
  her cells were guaranteed to lack the rejection
  gene.
• Five other pig clones lacking that gene were born
  in 2002.

6

• The miniature pig is more promising than the
  others because normal-sized pig organs are too
  large for transplantation in humans.
• Miniature pigs have organs similar in size to
  human organs.
• Young normal-sized pigs who have not reached full
  size could also be used.

7
How do you do it?

• Human cells are injected into a fetus halfway
  through gestation.
• Fetus develops and is born
• Cells from required organ are harvested

8
http//users.rcn.com/jkimball.ma.ultranet/BiologyP
ages/T/TransgenicAnimals.html
9
What are the benefits?

• There is a shortage of human organs to transplant
  into humans, and animal organs are a viable
  source of transplants that humans desperately
  need to survive.
• Growing organs in animals produces a supply of
  organs to do tests on.

10

• Good way to advance cloning and genetic research.
• Possible to genetically modify organs to reduce
  chances of organ rejection.

11
Why do we care?

• - using organs grown from pig cells for
  transplantation into humans may allow porcine
  endogenous retroviruses PERVs to jump to
  humanhosts
• -though the methods used allow for more of the
  persons cells to be in their new organs, the
  chance of organ rejection is still present and it
  is still risky to do such an operation

From a website.
12

• In some cases, if you attach a pigs organ to a
  human blood system, you can actually watch the
  organ being destroyed in front of your eyes
• This is because the human white blood cells
  recognize pig proteins as foreign.
• These proteins can also be found in bacteria and
  viruses, so our immune systems are programmed to
  attack them.

13
Why is it controversial?

• using human embryonic stem cells would avoid the
  risk of PERVs, but then opens up the controversy
  of whether destroying human embryos isethical
• having human cells in animals is also a very
  controversial issue how human will the animals
  become? How should we treat them then?

14

• there is a possibility that human cells may
  develop into gametes, and if two chimeras mate,
  there is a possibility that a human embryo might
  form and be trapped in, say, a mouse

15
Now what?

• Although the concept of transgenic animals is not
  new, the technology is still developing. This
  technology has the potential to do a great
  service for human kind. We do not yet know all
  of the risks, but the risks we do know caution us
  not to move too hastily with xenotransplantation.

16
The End
www.crt-online.org/ cartoons/xeno3.gif
17
How do we know so much?

• Animal to Human Organ Transplants, RDS,
  Online. Available http//www.rds-online.org.uk
  /pages/page.asp?i_ToolbarID5i_PageID161 2005,
  14 April.
• Dixon, Patrick. Changing Life on Earth
  Humanised Pigs and Other Beings Online.
  Available www.globalchange.com/xenotran.htm
  2005, 18 January.
• (2003). The Lord Dowding Fund for Humane
  Research, National Anti-Vivisection Society
  Online. http//www.navs.org.uk/research/about
  / 2005, 26 March.
• McDowell, Natasha. (2003, 13 January).
  Mini-pig clone raises transplant hope, New
  Scientist, Online. Available
  http//www.newscientist.com/article.ns?iddn3257
  2005, 18 January.
• Randerson, James. (23 December 2002). Working
  kidney grown in mouse, New Scientist, Online.
  Available http//www.newscientist.com/article.ns?
  iddn3216 2005, 18 January.
• (2000, 23 July). Scientists Discover
  Gene-Altered Animal Organs Could Set off Deadly
  Viruses in Humans, Organic Consumers
  Association, Online. Available
  http//www.organicconsumers.org/patent/organtrans.
  cfm 2005, 14 April.
• Transgenic Animals, Online 12 January 2005.
  Available http//users.rcn.com/jkimball.ma.ultran
  et/BiologyPages/T/TransgenicAnimals.html 2005,
  14 April.
• (2000, May). The Xeno Controversy in Britain
  The Leaked Documents, Frontline, Online.
  Available http//www.pbs.org/wgbh/pages/frontline
  /shows/organfarm/rights/controversy.html 2005,
  14 April.
• Weiss, Rick. (2004, 20 November). Of mice, men
  and in-between, MSNBC News Online. Available
  http//www.msnbc.msn.com/id/6534243/ 2005, 20
  April.
• Westphal, Sylvia Pagán. (2003, 17 December).
  Humanised organs can be grown in animals, New
  Scientist, Online. Available
  http//www.newscientist.com/article.ns?iddn4492
  2005, 18 January.