Table 1.
Selected biomarkers of AD in cerebrospinal fluid (CSF) and blood.
| Biomarker | Relevance in AD | Change in CSF/Blood of AD |
|---|---|---|
| Aβ42 | Distinguishing AD, mild cognitive impairment (MCI) that developed AD and preclinical AD from normal controls and other neurodegenerative disease | Consistently decreased in CSF, also decreased in blood [20,21,22,23,24,25,26,27,28,29,74,75,76,77,78] |
| Aβ40 | Inconsistent results for Aβ40 alone, Aβ42/Aβ40 ratio could be a better biomarker than Aβ42 alone | Aβ42/Aβ40 ratio consistently decreased in CSF, also decreased in blood [20,21,22,23,24,25,26,27,28,29,73] |
| Aβ38 | Inconsistent results for Aβ38 alone, Aβ42/Aβ38 ratio could be a better biomarker than Aβ42 alone for discrimination of AD from other dementia | Aβ42/Aβ38 ratio decreased in CSF, very few studies [27] |
| Aβ43 | Distinguishing AD from normal controls | Aβ43 increased and Aβ42/Aβ43 ratio decreased in blood, very few studies [9] |
| Aβ42/APP669-711 | Distinguishing AD from normal controls and MCI that developed AD | Decreased in blood, one study [75] |
| BACE1 | Distinguishing AD and MCI that developed AD from normal controls | Activity and levels increased in CSF, few studies [43,44,45,46] |
| β-sheet structure Aβ | Correlated with amyloid-PET and other established CSF AD biomarkers | Increased in blood, one study [79] |
| Aβ oligomer | Distinguishing AD and MCI that developed AD from normal controls | Increased in CSF, very few studies [31] |
| Flotillin | Distinguishing AD and MCI that developed AD from normal controls and vascular dementia (VaD); single blood marker | Decreased in CSF and blood, very few studies [91] |
| p-tau and t-tau | Distinguishing AD and MCI that developed AD from normal controls, p-tau 181 and p-tau 231 discriminates AD from other dementia | Consistently increased in CSF [38,39,40,41]; p-tau 181 increased in blood, several studies [80,81,82,83] |
| NF-L | Distinguishing AD from normal controls, but not other dementia; valuable for assessing neuronal injury | Increased in CSF and blood, several studies [41,49,50,51,52,53,54,84,85] |
| VILIP-1 | Distinguishing early AD and AD from normal controls, but not other dementia | Increased in CSF, inconsistent and limited results in blood [37,47,55,56,57,58,59,60,61,62] |
| Synaptic proteins (neurogranin, SNAP-25, synaptotagmin) | Distinguishing AD and MCI developed to AD from normal controls, but not other dementia | Increased in CSF, inconsistent and limited results in blood [37,47,61,63,64,65,66,67,68,69,70,71] |
| 18 Signaling proteins | Distinguishing AD and MCI developed to AD from normal controls | Pattern changed in blood, very few studies [86] |
| 10 plasma proteins | Predicting progression from MCI to AD | Pattern changed in blood, very few studies [87,88] |
| 10 phospholipids | Detecting preclinical AD from normal controls | Pattern changed in blood, very few studies [89] |
| 4 sphingolipids | Detecting prodromal and preclinical AD from normal controls | Increased in blood, very few studies [90] |
Aβ42, amyloid β-protein 42; MCI, mild cognitive impairment; Aβ40, amyloid β-protein 40; Aβ38, amyloid β-protein 38; Aβ43, amyloid β-protein 43; APP, amyloid precursor protein; CSF, cerebrospinal fluid; p-tau, phosphorylated tau; t-tau, total tau; VaD, vascular dementia; NF-L, neurofilament light; VILIP-1, visinin-like protein 1; SNAP-25, synaptosome-associated protein 25.