INS and early-onset autosomal dominant Alzheimer disease: <h4>Background</h4>Brain insulin resistance and cerebrovascular dysfunction emerge early in late-onset Alzheimer's disease, but how amyloid-β (Aβ) disrupts insulin signaling at the cerebrovascular blood-brain barrier-a major site of insulin receptor signaling and transport into the brain-remains unclear.<h4>Methods</h4>We exposed two distinct human blood-brain-barrier endothelial cell models to soluble Aβ40 or Aβ42 for 1 h, followed by 100 nM insulin for 10 min.