Immunolocalization of Kisspeptin Associated with Amyloid-β Deposits in the Pons of an Alzheimer’s Disease Patient

The pons region of the Alzheimer's disease (AD) brain is one of the last to show amyloid- β (A β ) deposits and has been suggested to contain neuroprotective compounds. Kisspeptin (KP) is a hormone that activates the hypothalamic-pituitary-gonadal axis and has been suggested to be neuroprotective against A β toxicity. The localization of KP, plus the established endogenous neuroprotective compounds corticotropin releasing hormone (CRH) and catalase, in tissue sections from the pons region of a male AD subject has been determined in relation to A β deposits. Results showed A β deposits also stained with KP, CRH, and catalase antibodies. At high magnification the staining of deposits was either KP or catalase positive, and there was only a limited area of the deposits with KP-catalase colocalization. The CRH does not bind A β , whilst both KP and catalase can bind A β , suggesting that colocalization in A β deposits is not restricted to compounds that directly bind A β . The neuroprotective actions of KP, CRH, and catalase were confirmed in vitro , and fibrillar A β preparations were shown to stimulate the release of KP in vitro. In conclusion, neuroprotective KP, CRH, and catalase all colocalize with A β plaque-like deposits in the pons region from a male AD subject.