Age-related Vascular Alterations in the Choroid Plexus: Novel Insights from Pathophysiology and Imaging Studies.

The choroid plexus (ChP), a highly vascularized brain structure responsible for cerebrospinal fluid (CSF) production, undergoes significant age-related changes that may contribute to neurodegenerative diseases involving disrupted immune regulation, fluid homeostasis and waste clearance. Compared to other brain regions, vascular research on the ChP remains limited despite its critical role as a central interface between the blood and CSF. This review focuses on age-related vascular and structural alterations in the ChP from both histopathological and neuroimaging perspectives, and explores their impact on CSF dynamics, immune regulation, and the integrity of the blood-CSF barrier (BCSFB). Rather than shrinking, the aging ChP often enlarges due to dystrophic changes, as shown in volumetric MRI studies. Histological studies reveal epithelial degeneration, basement membrane thickening, and stromal fibrosis in the normal aging process. In dementia such as Alzheimer's disease (AD), proteomic studies have identified upregulation of AD- and immune-related proteins, along with downregulation of proteins linked to CSF clearance and metabolic support. Emerging high-resolution contrast-enhanced MRI techniques now allow in vivo visualization of microvascular changes within the ChP, shedding light on its normal and abnormal aging processes. Understanding these alterations is critical, as they may influence the onset and progression of various neurological diseases such as AD, Parkinson's disease (PD), normal pressure hydrocephalus, and amyotrophic lateral sclerosis (ALS). The recent advancements and challenges described in this study underscore the need for deeper investigation into ChP aging to inform future diagnostic and therapeutic strategies of neurodegenerative diseases.