The increased intragraft mRNA expression of porcine MIP-1α, IL-8, HMGB1 and HSP90 seen at days 7 and 14 post-transplantation suggest that small xenoantigens such as these could diffuse through the microcapsule pores and initiate an immune response which correlates with the appearance of PFO seen at day 7. This evidence concerns the gene CXCL8 and Patent foramen ovale.