BackgroundChoroid plexus (CP) is an important tissue not only to produce cerebrospinal fluid (CSF) but also to regulate substances that are secreted into or absorbed from CSF through blood–cerebrospinal fluid barrier (BCSFB) formed by CP epithelial cells (CPECs). CPECs display signs of deterioration in aged and diseased people. However, whether CPECs in hypercholesterolemic animals develop such damage is not known.MethodsWe used cholesterol-fed wild-type or Watanabe hereditary hyperlipidemic (WHHL) rabbits of identical age to determine CPEC changes in terms of morphology and protein expression/localization.ResultsCompared with non-cholesterol-fed control rabbits, prolonged exposure to cholesterol reduced CPEC height and increased lipofuscin levels in CPECs, indicating cellular damage. Expression of aquaporin 1 on the apical membranes of CPECs was diminished in cholesterol-exposed rabbits, implying a reduced CSF-producing function in the CP. The rabbit macrophage-specific antibody (RAM11) immunoreaction became positive in CPECs adjacent to foam cells, indicating an alteration in this cell type.ConclusionCholesterol insults from the circulation (which is reflected by foam-cell accumulation in the CP) induce CPEC dysfunction, and the latter seems to be enhanced by foam cells in hypercholesterolemic rabbits.