HBB and Alzheimer disease: To assess the relevance of brain Hb and its clinical relevance in AD, we performed immunohistochemistry on postmortem hippocampal tissues from normal subjects and AD patients (Braak stages V and VI), with a focus on Hbβ due to computational modeling results and previous evidence of its significant impact on cognitive impairment.41 We detected the prevalent expression of Hbβ in hippocampal astrocytes under normal conditions, but it was significantly reduced in AD patients (Fig. 5a, b and Supplementary Fig. 13a, b).