Pig Heart Valves and Rejection

David Young dsfyoung at resunix.ri.sickkids.on.ca
Sun Apr 30 17:39:45 EST 1995

In article <Pine.A32.3.91.950427082136.214452B-100000 at acc.wuacc.edu>,
zzwolf at ACC.WUACC.EDU (wolf tom) wrote:

> Why are replacement heart valves from swine not subject to rejection 
> problems when translanted into humans? 

I think the simplest explanation is that porcine valves are variously
treated prior to implantation. Some of these treatments have included
glutaraldehyde fixation, but now I think there are different fixatives
being used. 

But I think the primary reason why there is no rejection is that valves
are not endothelialized. Endothelial cells convey most of the antigenicity
in xenografts. They contain many of the carbohyrates that are responsible
for xenograft rejection. Valvular proteins (eg collagen) may not be
inherently xenogenic, that is recipient lymphocytes may not recognize them
as being foreign. This is in contrast to other types of non-vascular
xenografts such as acellular matrix xenograft vessels. These vessels have
had their endothelial removed and yet they still provoke a cellular

Good Luck,

David Young, M.D.

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