Immunodistribution of amyloid beta protein (Aβ) and advanced glycation end-product receptors (RAGE) in choroid plexus and ependyma of resuscitated patients.

RAGE (receptor for advanced glycation end-products) participates in the influx transport of glycated Aβ (amyloid beta) from the blood to the brain. Because little is known of the RAGE operating in brain barriers such as those in the choroid plexus and ependyma, the aim of the present study was to examine the immunodistributions of RAGE and Aβ peptides in the choroid plexus where the blood-cerebrospinal fluid barrier (B-CSF) is located, and in ependyma of the brain ventricles associated with functions of the cerebrospinal fluid-brain barrier (CSF-B). The study was performed on patients over 65 years successfully resuscitated after cardiac arrest with survival a few weeks. The control group consisted of age-matched individuals who were not resuscitated and died immediately after cardiac arrest. In resuscitated patients, but not in controls, RAGE receptors were localized in choroid plexus (CP) epithelial cells and in ependymal cells bordering the brain ventricles. These cells form the B-CSF and CSF-B barriers. The presence of Aβ was detected within the CP blood vessels and in the basement membrane of the CP epithelium. In numerous cytoplasmic vacuoles of CP epithelial and ependymal cells Aβ protein was found and our observations suggest that the contents of those vacuoles were undergoing progressive digestion. The results demonstrated that CP epithelium and ependymal cells, equipped with RAGE receptors, not only play an important role in the creation of amyloid deposits in the brain but are also places where Aβ may be utilized. The RAGE transportation system should be a main target in the therapy of brain amyloidosis, a well-known risk factor of Alzheimer disease.