PDGFB and Alzheimer disease: A more recent study has also shown regulation of tight junction protein expression via PDGFβ and TGFβ signalling interactions [70]; moreover, levels of PDGFβ are altered in CSF and plasma from AD patients [71], and AD transgenic mouse models have also shown that a dysfunctional PDGFβ/PDGFRβ axis could lead to pericyte degeneration and BBB breakage [72].