Distinct neuroinflammatory patterns between cerebral microbleeds and microinfarcts in cerebral amyloid angiopathy

In this neuropathological study, we investigated neuroinflammation surrounding recent and old cerebral microbleeds (CMBs) and cerebral microinfarcts (CMIs) in 18 cases of cerebral amyloid angiopathy (CAA). We used several serial stainings and immunolabellings to identify microvascular lesions, define their recent or old stage, and characterize neuroinflammatory response (scavenging activity and astrogliosis). We found that both CMBs and CMIs induce a neuroinflammatory response, which was more pronounced in old lesion than recent. Astrogliosis and scavenging activity were differentially prominent according to the ischemic/hemorrhagic nature of the lesion. Our findings provide insights into the pathophysiology of microvascular injuries in CAA.