Thank you for your interesting results, which confirm nicely that the structure of the vasculature can change rapidly. We found, for example, that in rabbit esophageal vein that there was a doubling of material just four days after induction of portal hypertension (Juhl CO, Jensen LS, Mulvany MJ: Time course development of changes in the structure and reactivity of small veins from portal hypertensive rabbits. Clin Sci 1989,77:205-211.)
Maybe regression can occur just as quickly? Incidentally, are you sure that you are observing regression and not failure to develop?