ENPEP and familial hypercholesterolemia: Moreover, a cardiovascular risk factor (CVD) as hypercholesterolemia can contribute to this effect through the alteration of aminopeptidases A and N (AP-A and AP-N), as previously reported on a transgenic mouse model (CYP27Tg), overproducing 27-hydroxycholesterol (27-OH), a cholesterol metabolite that can cross the blood-brain barrier (BBB).