"would apabetalone need to cross the BBB to have some success around cognitive increase. Do we have any data around the reverse transport of amyloid plaque?,,Perhaps the increase of kidney function and the down regulation of inflammation is part of the solution to puting dementia in check etc." 

Crossing the BBB mahy not be necessary to elicit improvements in cognitive function. As I acknowledged in my post, potential benefitical effects could very well be indirect due to effects of drug on circulating factors (lipoproteins, inflammatory mediators, etc).

BDAZ