APOE and Alzheimer disease: Findings from Philbert et al. [54] indicated a pervasive underlying mechanism in which micro-vasculopathy promoted erythrocyte leakage, elevating tissue-free hemoglobin and causing the observed increases in HP in the brains of sporadic AD while Cigliano et al. found that HP interacted with APOE and Aβ and influenced their crosstalk [55].