>In a short article it is, I know, difficult to give many details. It is, however, not clear to me whether you have measured an increase in terminal growth, or have calculated it. How dependent on your model is your conclusion that local metabolic factors, not mechanical factors, are causing rarefaction?
Terminal growth was determined experimentally. We measured an entire arteriolar tree with all its branches on day 7, 10 and 14 during embryonic development.
Our model is an embryonic one and therefore different from more static adult microvascular beds. We observe a strong microvascular growth during a period in which pressure in the feed artery of the arteriolar bed we observed is rapidly rising (pressure data not shown). This pleads against pressure-induced regression of terminal arterioles. However, this conclusion pertains only to the model we studied.