シンポジウム15：ARIAの発症機序と制御への展望
脳アミロイド血管症の病態
キーワード:
intramural periarterial drainage (IPAD),
amyloid β protein (Aβ),
iatrogenic,
genetic,
inflammation
2025 年 42 巻 3 号 p. 422-425
詳細
2025 年 42 巻 3 号 p. 422-425
Cerebral amyloid angiopathy (CAA) is a disorder characterized by the deposition of amyloid in the meningeal and cortical blood vessels. Sporadic amyloid β protein (Aβ)–type CAA is the most common form of CAA, while there are sporadic and genetic forms of CAA depending on the amyloidogenic proteins. CAA is a well–known cause for recurrent cerebral lobar hemorrhages, cerebral infarcts, transient focal neurological episodes, cognitive impairment, and inflammation/vasculitis (CAA–related inflammation, CAA–ri). The prevalence of sporadic Aβ–type CAA increases with age. The crude prevalence rates of CAA–related intracerebral hemorrhage and CAA–ri in Japan were 4.64 and 0.13 per 100,000 population, respectively. Although details of the pathomechanisms of sporadic Aβ–type CAA have been uncertain so far, drainage pathways of interstitial fluid, such as intramural periarterial drainage (IPAD) and glymphatic system, and apolipoprotein E would be related to development of CAA. Deposited Aβ can develop CAA–ri due to immune reaction against Aβ. As similar pathomechanisms are shared between CAA–ri and amyloid–related imaging abnormalities (ARIAs) in patients with Alzheimer disease who received immunotherapy for Aβ, further elucidation of the pathomechanisms of CAA–ri is crucial for the prevention and treatments of ARIAs. Recently, the number of patients with iatrogenic CAA who had past history of brain injury or brain surgery over 25 years previously of the onset of CAA manifestations are increasing. Propagation of Aβ from the surgical instruments or failure of Aβ drainage from the brain could cause iatrogenic CAA. Regarding genetic CAA, transthyretin–type CAA emerged in patients with ATTRv amyloidosis with long duration. Amyloidogenic transthyretin stemmed from choroid plexus deposits on the vessel walls as CAA. There have been no effective treatments for CAA, although CAA–ri could be treated by corticosteroid and immunosuppression therapy. Further studies are essential to improve clinical care for patients with CAA.
