MMP9 and Salla disease: Mechanistically, subarachnoid blood products and iron deposits as well as SD were reported to trigger endothelial and perivascular inflammation, upregulation of matrix metalloproteinase-9 (MMP-9) and BBBD.50, 51, 52, 53, 54, 55, 56, 57, 58, 59 Subsequent serum protein extravasation—most notably albumin—activates astrocytic TGFβ signalling11 and disrupts ion/glutamate homoeostasis lowering seizure threshold.60