Table 2.
Baseline characteristics of included PD studies.
| Author, Year | N(HC/PD) | Age (mean ± SD)(HC/PD) | Male (N.)(HC/PD) | Materials | Metabolites | Fasting status | Key findings |
|---|---|---|---|---|---|---|---|
| Sorgdrager, 2019 (21) | (35/26) | 71.3 (10.7)/73.4 (6.5) | 18/20 | CSF | TRP, KYN, 3-HK | Tryptophan levels lower in PD group Kynurenine levels higher in PD group 3-HK levels lower in PD group |
|
| Sorgdrager, 2019 (21) | (38/32) | 71.3 (10.7)/73.4 (6.5) | 18/20 | Serum | TRP, KYN, 3-HK | Tryptophan levels significantly lower in PD group Kynurenine levels higher in PD group 3-HK levels lower in PD group |
|
| Lwaoka, 2019 (65) | (13/20) | 69 (16.7)/69 (6.4) | 9/9 | CSF | TRP, KYN, KYNA,3-HK | CSF samples were obtained from participants by lumbar puncture between 09:00 and 10:00 AM after several minutes of left-sided bedrest and before breakfast. | Tryptophan levels higher in PD group Kynurenine levels significantly higher in PD group Kynurenic acid levels lower in PD group 3-HK levels significantly higher in PD group |
| Havelund, 2017 (66) | (14/8) | 55.8 (11.6)/62.6 (6.6) | 8/5 | CSF | KYN, KYNA,AA,3-HK | Plasma and cerebrospinal fluid samples were collected after overnight fasting and 1-2 hours after intake of L-DOPA or other anti-Parkinson medication. | Kynurenine levels higher in PD group Kynurenic acid levels higher in PD group ANT levels higher in PD group 3-HK levels lower in PD group |
| Havelund, 2017 (66) | (14/8) | 55.8 (11.6)/62.6 (6.6) | 8/5 | Plasma | KYN, KYNA, AA, 3-HK | Kynurenine levels lower in PD group Kynurenic acid levels lower in PD group ANT levels higher in PD group 3-HK levels lower in PD group |
|
| Oxenkrug, 2017 (40) | (24/18) | Range: 50 to 74 | 12/11 | Serum | TRP, KYN, KYNA, AA | Overnight fasting blood samples were collected | Tryptophan levels significantly lower in PD group Kynurenine levels significantly higher in PD group Kynurenic acid levels significantly higher in PD group ANT levels significantly higher in PD group |
| Chang, 2017 (51) | (82/82) | 62.83 (12.66)/62.87 (12.49) | 50/50 | Plasma | TRP, KYN, KYNA, AA, 3-HK, QUIN | Tryptophan levels significantly lower in PD group Kynurenine levels significantly lower in PD group Kynurenic acid levels significantly lower in PD group ANT levels lower in PD group 3-HK levels higher in PD group QUIN levels significantly higher in PD group |
|
| Hartai, 2005 (24) | (17/19) | 67.8 (12.4)/69.1 (10.4) | 8/11 | Plasma | KYNA | Kynurenic acid levels lower in PD group | |
| Ruiz, 1995 (54) | (15/23) | 39.0(17.8)/58(10.0) | -/13 | CSF | 5-HIAA | Lumbar CSF after overnight bed-rest and fasting. | 5-HIAA levels higher in PD group |
| Molina, 1997 (64) | (45/31) | 57.8 (15.4)/62.6 (8.7) | 18/11 | CSF | TRP | Tryptophan levels higher in PD group | |
| Molina, 1997 (64) | (45/31) | 57.8 (15.4)/62.6 (12.5) | 18/11 | Plasma | TRP | Blood samples for metabolomics analysis were collected from subjects who were asked to be on fasting overnight for 8 h. | Tryptophan levels significantly lower in PD group |
| Tohgi, 1993 (63) | (10/16) | 65.5 (6.2)/62.6 (8.7) | CSF | TRP, KYN,5-HIAA,3-HK | Lumbar CSF after overnight bed-rest and fasting. | Tryptophan levels lower in PD group Kynurenine levels significantly lower in PD group 5-HIAA significantly lower in PD group 3-HK levels significantly lower in PD group |
|
| Tohgi, 1993 (62) | (16/16) | 63.9 (8.1)/62.6 (8.7) | CSF | TRP, KYN, 5-HIAA,3-HK | Lumbar CSF after overnight bed-rest and fasting. | Tryptophan levels lower in PD group Kynurenine levels significantly lower in PD group 5-HIAA levels lower in PD group 3-HK levels significantly lower in PD group |
|
| Beal, 1992 (47) | (18/11) | 69(3)/66(4) | 8/8 | Postmortem | 3-HK | 3-HK levels lower in PD groups |