The Next Pig Thing: Animal to human transplants on the horizon.
Ever thought it possible to one day have an organ from a pig transplanted to replace a failing human organ? Well the likelihood of this doesn’t seem to be as far away as once thought, with two groups of scientists having produced cloned, genetically engineered pigs with tissue suitable for transplantation into humans – known as xenotransplantation.
Every year thousands of people die waiting for a suitable donor organ, it was therefore an automatic response to research alternative transplant options to alleviate this waiting period and ultimately save lives. But why pigs? Most importantly humans and pigs share the same size organs (approximately) and pig heart valves have been in use in human heart surgery for over 10 years with great success.
However xenotransplantation doesn’t come without its challenges, with the main technical barrier being the aggressive immune system response to foreign tissues where antibodies (of the hosts’ immune system) attach to the sugars on the surface of the transplanted organ and ultimately reject it. Scientists overcame this by knocking out the gene which encodes an enzyme (α-1,3-galactosyltransferase) necessary for attachment of these sugars to the surface of the pigs’ cells.
The scientific community is still concerned that viruses such as porcine endogenous retroviruses may be transferred across the species barrier through animal to human transplantations with potentially devastating effects on the human population. Many moral and ethical issues have also been raised concerning xenotransplantation, however if resolved this method of transplantation could have great implications in bio – medical science and on thousands of peoples’ lives.
Every year thousands of people die waiting for a suitable donor organ, it was therefore an automatic response to research alternative transplant options to alleviate this waiting period and ultimately save lives. But why pigs? Most importantly humans and pigs share the same size organs (approximately) and pig heart valves have been in use in human heart surgery for over 10 years with great success.
However xenotransplantation doesn’t come without its challenges, with the main technical barrier being the aggressive immune system response to foreign tissues where antibodies (of the hosts’ immune system) attach to the sugars on the surface of the transplanted organ and ultimately reject it. Scientists overcame this by knocking out the gene which encodes an enzyme (α-1,3-galactosyltransferase) necessary for attachment of these sugars to the surface of the pigs’ cells.
The scientific community is still concerned that viruses such as porcine endogenous retroviruses may be transferred across the species barrier through animal to human transplantations with potentially devastating effects on the human population. Many moral and ethical issues have also been raised concerning xenotransplantation, however if resolved this method of transplantation could have great implications in bio – medical science and on thousands of peoples’ lives.
Written by: Bethany Price
Student Number: 41206627
References:
BBC News Online, 2002. “Animal Transplants: A step closer?” Visited 23rd May, 2007 http://www.bbc.co.uk/2/hi/science/nature/1740316.stm
Dobson, R. 2002. “Scientists produce genetically engineered, cloned pigs for
Xenotransplantation.” http://www.bmj.com/cgi/content/full/324/7329/70/f Visited 23rd May, 2007.
Lee, J., Graham, W., Richard, A., Moran, C. 2002. “Characterizing and Mapping Porcine Endogenous Retroviruses in Westran Pigs” Journal Of Virology 76 (1) pg 5548 – 5556. http://jvi.asm.org/cgi/content/full/76/11/5548 Visited 25th May
Singer, E., 2006. “Pig – to – Human Transplants on the Horizon” Visited 23rd May, 2007 http://www.technologyreview.com/Biotech/17596/page2/
Wong, B., Yamada, K., Okumi, M., Weiner, J., O’Malley, P., Tseng, Y., Dor, F., Cooper, D., Saidman, S., Grismer, A., Sachs. D., “Allosensitisation Does Not Increase the Xenoreactivitiy to [alpha] 1,3 – Galactosyltransferase Gene Knockout Minature Swine in Patients on Transplantion Waiting Lists.” Journal of the Transplantation Society 82 (3) pg 314 – 319 https://www.library.uq.edu.au/ezp.php?url=http://gateway.ovid.com/ovidweb.cgi?T=JS&PAGE=fulltext&D=ovft&MODE=ovid&NEWS=N&SEARCH=0041-1337.is.%20and%202006.yr.%20and%20314.pg
Dobson, R. 2002. “Scientists produce genetically engineered, cloned pigs for
Xenotransplantation.” http://www.bmj.com/cgi/content/full/324/7329/70/f Visited 23rd May, 2007.
Lee, J., Graham, W., Richard, A., Moran, C. 2002. “Characterizing and Mapping Porcine Endogenous Retroviruses in Westran Pigs” Journal Of Virology 76 (1) pg 5548 – 5556. http://jvi.asm.org/cgi/content/full/76/11/5548 Visited 25th May
Singer, E., 2006. “Pig – to – Human Transplants on the Horizon” Visited 23rd May, 2007 http://www.technologyreview.com/Biotech/17596/page2/
Wong, B., Yamada, K., Okumi, M., Weiner, J., O’Malley, P., Tseng, Y., Dor, F., Cooper, D., Saidman, S., Grismer, A., Sachs. D., “Allosensitisation Does Not Increase the Xenoreactivitiy to [alpha] 1,3 – Galactosyltransferase Gene Knockout Minature Swine in Patients on Transplantion Waiting Lists.” Journal of the Transplantation Society 82 (3) pg 314 – 319 https://www.library.uq.edu.au/ezp.php?url=http://gateway.ovid.com/ovidweb.cgi?T=JS&PAGE=fulltext&D=ovft&MODE=ovid&NEWS=N&SEARCH=0041-1337.is.%20and%202006.yr.%20and%20314.pg
