Table 1.
Baseline characteristics of included AD studies.
| Author, Year | N(HC/AD) | Age (mean ± SD)(HC/AD) | Male (N.)(HC/AD) | Disease duration (SD) | MMS scores | Materials | Metabolites | Fasting status | Key findings |
|---|---|---|---|---|---|---|---|---|---|
| González-Sánchez, 2020 (38) | (23/20) | 64.7 (10.8)/73.3 (7.2) | 15/7 | 4 (1.6) | 16 | CSF | TRP, KYNA | Tryptophan levels higher in AD group Kynurenic acid levels significantly higher in AD group |
|
| González-Sánchez, 2020 (38) | (20/9) | Serum | TRP, KYNA | Tryptophan levels lower in AD group Kynurenic acid levels higher in AD group |
|||||
| Sorgdrager, 2019 (21) | (38/33) | 71.3 (10.7)/73.7 (6.0) | 18/15 | 3 | 16.2 | Serum | KYN, TRP,3-HK | Kynurenine levels higher in AD group Tryptophan levels lower in AD group 3-HK lower in AD group |
|
| Sorgdrager, 2019 (21) | (35/31) | 71.3 (10.7)/73.7 (6) | 18/15 | CSF | KYN, TRP | Kynurenine levels higher in AD group Tryptophan levels higher in AD group |
|||
| Giil, 2017 (19) | (42/42) | 78.55 (6.84)/78.46 (6.34) | Plasma | KYN, TRP, KYNA, AA, 3-HK, QUIN | Kynurenine levels significantly lower in AD group Tryptophan levels significantly lower in AD group Kynurenic acid levels lower in AD group Anthranilic acid significantly lower in AD group 3-HK lower in AD group QUIN levels significantly lower compared to controls |
||||
| Daouk, 2013 (39) | (38/40) | 69.5/69 | 13/10 | 3.7 | 23 | CSF | 5-HIAA | 5-HIAA levels higher in AD group | |
| Oxenkrug, 2017 (40) | (24/20) | Range: 60 to 75 | 12/8 | 21.6 | Serum | KYN, TRP, KYNA, AA, 3-HK | Kynurenine levels higher in AD group Tryptophan levels lower in AD group Kynurenic acid levels lower in AD group Anthranilic acid significantly lower in AD group 3-HK higher in AD group |
||
| Gulaj, 2010 (22) | (18/34) | 76.17 (7.30)/78.82 (5.66) | 5/10 | Plasma | KYN, TRP, KYNA, AA, QUIN | In AD patients and healthy voluntaries blood was taken in the morning between 8.00-9.00 a.m. | Kynurenine levels higher in AD group Tryptophan levels significantly lower in AD group Kynurenic acid levels significantly lower in AD group Anthranilic acid significantly lower in AD group QUIN levels significantly higher in AD group |
||
| Hartai, 2007 (41) | (31/28) | 73 (8.3)/77 (6.3) | 10/6 | 21 | Serum | KYN, KYNA | The blood samples were taken between 9 and 11 am, separated immediately and kept at 80 -C until measurements. None of the subjects were on a special diet. | Kynurenine levels higher in AD group Kynurenic acid levels significantly lower in AD group |
|
| Widner, 2000 (28) | (20/21) | 73.4 (7.4)/74.4 (5.4) | 10/6 | Serum | KYN, TRP | Kynurenine levels higher in AD group Tryptophan levels lower in AD group |
|||
| Baran, 1999 (42) | (13/11) | 80.1 (2.4)/81 (1.9) | 7/2 | Postmortem | KYN, KYNA,3-HK | Kynurenine levels lower in AD group Kynurenic acid levels higher in AD group 3-HK lower in AD group |
|||
| Bonaccorso, 1998 (43) | (15/15) | 75.6 (9.1)/78.4 (10.3) | 8/3 | Plasma | TRP | blood samples were taken at 7:45 ( ± 30 min) after an overnight fast. | Tryptophan levels lower in AD group | ||
| Fekkes, 1998 (44) | (17/14) | 70.1 (1.3)/73.6 (6.3) | 17/4 | Plasma | TRP | blood (4ml) was drawn between 11.00 and 12:00 a.m. | Tryptophan levels lower in AD group | ||
| Tohgi, 1995 (45) | (10/15) | 69 (6)/68 (6) | 3.4 (2.1) | 17.1 | CSF | KYN, TRP,5-HIAA,3-HK | Lumbar CSF was obtained between 9 and 10 o’clock in the morning, after overnight bedrest and fasting | Kynurenine levels lower in AD group Tryptophan levels lower in AD group 5-HIAA levels higher in AD group 3-HK significantly lower in AD group |
|
| Tohgi, 1992 (46) | (10/14) | 68.5 (6.1)/68.4 (10.1) | 3.7 (3.5) | 12.9 | CSF | KYN, TRP,5-HIAA, 3-HK | Lumbar CSF was obtained with the patients in the lateral decubitus position between 09.00 and 10.00 h after overnight bed-rest and fasting. | Kynurenine levels lower in AD group Tryptophan levels lower in AD group 5-HIAA levels lower in AD group 3-HK significantly lower in AD group |
|
| Beal, 1992 (47) | (21/13) | 63 (3)/- | 11/- | Postmortem | KYN, KYNA, 3-HK | Kynurenine levels higher in AD group Kynurenic acid levels lower in AD group 3-HK higher in AD group |
|||
| Pearson, 1992 (48) | (12/12) | 76(10)/79(7) | 7/3 | Postmortem | 3-HK | 3-HK higher in AD group | |||
| Baker, 1989 (49) | (13/12) | 82.5(7.1)/80.6(7.3) | 4/4 | Postmortem | 5-HIAA | 5-HIAA levels significantly lower in AD group | |||
| Kay, 1986 (50) | (14/30) | 64.7 (3.1)/66.8 (1.7) | 16.2 | CSF | 5-HIAA | Fasted | 5-HIAA levels higher in AD group |