Maresin1 Improves Angiogenesis and Cognitive Function by Regulating Perivascular Macrophages in Rats with Chronic Cerebral Hypoperfusion.

Population aging imposes a substantial dementia burden. Chronic cerebral hypoperfusion (CCH) serves as a crucial early pathological basis for Alzheimer's disease (AD) and Vascular Dementia (VaD). Our previous studies have demonstrated that macrophage-derived docosahexaenoic acid metabolite Maresin1 can ameliorate CCH-induced cognitive impairment, though the underlying angiogenesis-related mechanisms remain to be elucidated. We developed a rat model of chronic cerebral hypoperfusion using the bilateral common carotid artery occlusion surgical approach. Cognitive improvements and angiogenic mechanisms by Maresin1 were systematically evaluated using behavioral assessments, immunofluorescence techniques, Western blotting (WB), ELISA, and cerebral blood flow measurements via laser Doppler. Our findings revealed that Maresin1 administration significantly ameliorated CCH-induced cognitive deficits, promoted hippocampal angiogenesis and enhanced cerebral perfusion. Further analysis showed significant enhancement of IGF-1/p-Akt/VEGF/eNOS signaling pathway activation by Maresin1, and the increased VEGF expression was predominantly mediated by perivascular macrophage (pvMΦ) activation. Depletion of pvMΦ using clodronate liposomes suppressed the VEGF upregulation and cognitive improvement mediated by Maresin1. Our research demonstrates that IGF-1/p-Akt/VEGF pathway activation in pvMΦ plays a crucial role in Maresin1-mediated angiogenesis in CCH rats.