These biocompatibility studies evaluate the effects of Dacron, absorbable polymeric, and compound prostheses containing both elements in various constructions on the migration, proliferation, and functional characteristics of regenerating endothelial and smooth muscle-like cells in the rabbit aorta model. Prosthesis/tissue complexes explanted after 2 weeks to 9 months were studied grossly, photographed, sectioned for light microscopy and scanning and transmission electron microscopy, and assayed for 6-keto-PGE1 alpha contents in inner capsular tissues. Polyglycolic acid, polyglactin 910, or polydioxanone prostheses elicited a transinterstitial migration and proliferation of primitive mesenchymal cells that differentiated into smooth muscle-like myofibroblasts and a surface repopulation of confluent endothelial-like cells paralleling the time course of macrophage-mediated prosthetic dissolution. Even small Dacron components (20%) woven into or surrounding the absorbable polymer significantly inhibited these processes, yielding significantly thinner, less cellular inner capsules with lower 6-keto-PGF1 alpha contents. These studies show the augmentation of clinically efficacious arterial regenerative activities by polymers phagocytosed by macrophages and the inhibition of these activities by Dacron.