A clue in the search for CSF SVD biomarkers comes from studies on patients with SVD-related dementia (both pure SVD and mixed SVD/AD pathology), who showed increased levels of CSF α-1 antitrypsin, tissue inhibitor of metalloproteinase-1 (TIMP-1), plasminogen activator inhibitor-1 (PAI-1) and apolipoprotein H (ApoH), with respect to pure AD patients and healthy control subjects [93]. Here, SERPINE1 is linked to snowflake vitreoretinal degeneration.