TNFRSF11B and Parkinson disease: Elevated SAP3 levels, also found in the cerebrospinal fluid of AD and Parkinson's disease patients,27, 84 have been linked to the degeneration of pericytes that are crucial for the function of BBB;85, 86 increased MIC‐1 and OPG are associated with endothelial dysfunction;87, 88, 89 increased CDCP1 with tight junction degeneration;90, 91, 92 and MARCKSL1 and SVEP1 with endothelia integrity.93, 94, 95