Transplantation Induced Functional/Morphological Changes in Rat Aorta Allografts Differ from Those in Arteries of Rat Kidney Allografts

Abstract

The functional/morphological changes observed in rat aorta allografts were compared with those seen in the arteries of rat kidney allografts.Untreated allografts (F344 to LEW) were collected at various times post transplantation (Tx). Vascular smooth muscle cell (SMC) constriction to phenylephrine (Phe) and endothelial cell (EC) dependent relaxation to acetylcholine (Ach) were assessed. Neointima formation in graft vessels was assessed by histology.In aorta allografts, the effects of Phe and Ach were irreversibly abolished within 3–2 weeks post Tx. Neointima formation was consistently detected between 4 and 8 weeks post Tx.In kidney allografts, sign of vasculopathy was seen in 10, 30 and 40% of resistance arteries at 8, 16 and 33 weeks post Tx, respectively. In the main renal artery, substantial neointima formation was not apparent before 33 weeks post Tx, the vasoconstrictor effect of Phe was fully maintained until then, and Ach induced vasorelaxation was irreversibly reduced by approximately 70% from week 2 post Tx onwards.These results indicate that the post Tx functional/morphological changes seen in aorta allografts do not reflect those seen in arteries of kidney allografts. Hence, renal arteries from rat kidney allografts can be considered as a more relevant model to study the cascade of events leading to Tx induced CGA in solid organ allografts.