We’re not talking about xenotransplantation of living tissues though.
I appreciate that. I did have the idea that the stringency of the washes in decellularization wouldn't be enough to get rid of viruses. Looked into it and it turns out that might not be true. Washing might be enough:
https://www.ncbi.nlm.nih.gov/pubmed/12115437
Not sure how compatible this is w/ the protocol used in the OP.
The number of normal pigs available isn't really significant...
Even if you assume that the donor pigs wouldn't be heavily genetically engineered (and they probably would be), the risk of xenogeneic infection (ie pig viruses being carried over to the patient) means that they'd have to be raised under sterile conditions, so normal pigs are useless.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC88959/https://www.ncbi.nlm.nih.gov/pubmed/11041495
Not sure how compatible this is w/ the protocol used in the OP.