Multi-functional memantine nitrate attenuated cognitive impairment in models of vascular dementia and Alzheimer's disease through neuroprotection and increased cerebral blood flow.

Alzheimer's disease (AD) and vascular dementia (VaD) are two prevalent forms of dementia. VaD is linked to cerebrovascular lesions, such as those from white matter ischemia and chronic cerebral hypoperfusion, which can also occur in AD. Nitric oxide (NO) regulates cerebral blood flow (CBF) in the central nervous system. Memantine is an NMDA receptor antagonist approved for AD treatment. This study investigated the efficacy and molecular mechanism of MN-08, a novel memantine nitrate, in one VaD model (2VO) and two AD models (APP/PS1 mice and Aβ1-42-induced mice). MN-08 increased CBF, ameliorated cognitive and memory functions in VaD and AD, and was more effective than memantine. MN-08 increased the survival rate of CA1 neurons and mitigated white matter lesions and axonal damage. Moreover, MN-08 protected neurons from OGD-induced loss and promoted axonal outgrowth in the hippocampus by upregulating phosphorylated Akt (p-Akt), glycogen synthase kinase-3β (p-GSK3β), and high-molecular-weight neurofilaments (p-NFH). The beneficial effects of MN-08 were attenuated by carboxy-PTIO, a potent NO scavenger, suggesting that MN-08-derived NO may alleviate cognitive impairment from cerebral hypoperfusion. Taken together, our studies demonstrate that MN-08 is a promising therapeutic agent for the treatment of dementia including VaD and AD.