血管性失智症是僅次於阿茲海默症的第二大失智症，目前的研究已經知道有25%-30%缺血性中風的病患會發現有失智症產生，高血壓是中風以及失智症共同的風險因子。大腦中的腎素-血管收縮素系統會藉由調控自主神經系統參與在高血壓的進展當中，除此之外，也知道了腎素-血管收縮素系統在阿茲海默症的病患當中也有過度表達的現象，目前已知腎素-血管收縮素系統會調控細胞自噬、發炎反應以及氧化壓力，但是對於腎素-血管收縮素系統調控那些機制以及是否參與在血管性失智症當中以及目前還不清楚。所以我們假設腎素-血管收縮素系統會藉由調控自主神經系統的功能參與在血管性失智症的病程當中。我們的結果顯示中風後的一個月及兩個月會有記憶喪失、情緒障礙的病徵產生。也發現了中風後的短期自主神經系統障礙(血壓不正常上升)會預示著兩個月後的自主神經系統的障礙(血壓不正常上升)，除此之外，也發現了短期自主神經障礙與兩個月後記憶喪失的情況為正相關，也就是說短期血壓上升越明顯，兩個月後的記憶喪失就越嚴重。進一步探討腎素-血管收縮素系統的表現，發現在控制血壓的腦區PVN、RVLM及控制記憶的腦區HF還有控制情緒AMY的腦區腎素-血管收縮素系統的表現是處於一個不平衡的情形，並且使用了AT1R的抑制劑後治療自主神經功能障礙後，可以去緩解血管性失智症的記憶喪失及情緒障礙，總和上述所說我們可以知道腎素-血管收縮素系統會藉由調控自主神經功能參與在血管性失智症的進展中。

Vascular dementia is the second leading form of dementia after Alzheimer's disease plaguing the elderly population. Current evidence suggests that 25-30% of ischemic stroke survivors develop immediate or delayed VaD. Hypertension is a common risk factor for stroke and dementia and, particularly, the brain renin–angiotensin system involves in sympathetic and parasympathetic arms of the autonomic nervous system to promote the development of hypertension. Whereas previous studies indicated that hyperactivity of the RAS is associated with the pathogenesis of Alzheimer's disease. Whether brain RAS contributes to VaD still remains unclear. Moreover, recent studies have demonstrated that brain autophagy, oxidative stress and inflammation in neuron can be regulated by RAS. So, we hypothesized that brain RAS contributes to ANS dysfunction in VaD progression. Our results showed that spatial memory loss and mood disorder were observed at one and two months after VaD. The acute and transient ANS dysfunction (represented by elevated blood pressure) on day one after VaD forecasted chronic ANS dysfunction at one and two months after VaD. Moreover, VaD-induced memory loss was positively correlated with acute and transient and chronic ANS dysfunction. In addition, AT1R blocker losartan and candesartan cure transient ANS dysfunction (represented by elevated blood pressure) on day one after VaD and alleviate memory loss and mood disorder at one and two months after VaD. Taken together, RAS hyperactivity contributed to ANS dysfunction in VaD progression.

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