Advancements in investigating the role of cerebral small vein loss in Alzheimer's disease-related pathological changes

Alzheimer's disease (AD) is the prevailing type of dementia in the elderly, yet a comprehensive comprehension of its precise underlying mechanisms remains elusive. The investigation of the involvement of cerebral small veins in the advancement of AD has yet to be sufficiently explored in previous studies, primarily due to constraints associated with pathological staining techniques. However, recent research has provided valuable insights into multiple pathophysiological occurrences concerning cerebral small veins in AD, which may manifest sequentially, concurrently, or in a self-perpetuating manner. These events are presumed to be among the initial processes in the disease's progression. The impact of cerebral small vein loss on amyloid beta (Aβ) clearance through the glial lymphatic system is noteworthy. There exists a potential interdependence between collagen deposition and Aβ deposition in cerebral small veins. The compromised functionality of cerebral small veins can result in decreased cerebral perfusion pressure, potentially leading to cerebral tissue ischemia and edema. Additionally, the reduction of cerebral small veins may facilitate the infiltration of inflammatory factors into the brain parenchyma, thereby eliciting neuroinflammatory responses. Susceptibility-weighted imaging (SWI) is a valuable modality for the efficient assessment of cerebral small veins, precisely the deep medullary vein (DMV), and holds promise for the identification of precise and reliable imaging biomarkers for AD. This review presents a comprehensive overview of the current advancements and obstacles to the impairment of cerebral small veins in AD. Additionally, we emphasize future research avenues and the importance of conducting further investigations in this domain.