I know for microvasculature
New microvasculature (arterioles, venules) are always more permeable as they lack pericytes.
and then I have this sentence about new blood vessels (not specific)
New vessels contain initially only proliferative endothelium, the basement membrane has not formed yet, and pericytes are absent.
However, I think pericytes are only around microvasculature.
I think the second statement is correct for microvasculature too.
Why are new vessels more permeable in microasculature?