Table 4.
Changes in metabolites and pathways that appear to be disease-specific for RA, PsA, or Ps.
| Metabolites or Pathway | Trend | Indication | Matrix | Instruments | Biomarker Categories * |
References |
|---|---|---|---|---|---|---|
| Nucleotides (ATP, GDP, ADP) | ↑ | RA (compared to PsA and SLE) | Plasma | CE–TOF-MS | D | Kishikawa 2021 [60] |
| Ethanolamine phosphate | ↑ | |||||
| 6-Aminohexanoic acid | ↑ | |||||
| Taurine | ↑ | |||||
| Xanthine | ↓ | |||||
| Glutamine | ↑ | RA (compared to PsA) | Serum | GC–TOF-MS UPLC–MS |
D | Madsen 2011 [34] |
| Heptanoic acid | ↑ | |||||
| Succinic acid | ↑ | |||||
| Pseudouridine | ↑ | |||||
| Inosine | ↑ | |||||
| Guanosine | ↑ | |||||
| Arabitol | ↑ | |||||
| Cystine | ↑ | |||||
| Cysteine | ↑ | |||||
| Phosphoric acid | ↑ | |||||
| Aspartic acid | ↓ | |||||
| Glutamic acid | ↓ | |||||
| Histidine | ↓ | |||||
| Serine | ↓ | |||||
| Arachidonic acid | ↓ | |||||
| Cholesterol | ↓ | |||||
| Threonic acid | ↓ | |||||
| 1-Monooleoylglycerol | ↓ | |||||
| Alanine, Threonine, Leucine, Valine |
↑ | PsA (compared to seronegative RA) | Serum | 1H-single-pulse NMR and CPMG NMR | D | Souto-Carneiro 2020 [61] |
| Acetic acid | ↑ | |||||
| Lactic acid | ↑ | |||||
| Choline | ↑ | |||||
| Creatine | ↑ | |||||
| Phenylalanine | ↓ | |||||
| Specific lipid ratios | ↓ | |||||
| Lignoceric acid | ↑ | PsA (compared to Ps) | Serum | GC–TOF-MS | D | Armstrong 2014 [66] |
| α-Ketoglutaric acid | ↓ | |||||
| Tyramine | ↑ | PsA (compared to Ps) | Plasma | CE–TOF-MS LC–TOF-MS |
D | Kishikawa 2021 [71] |
| Mucic acid | ↓ | |||||
| Phospholip. LA (18:2) | ↓ | PsA (compared to Ps) | Plasma | UPLC–QTOF-MS GC-FID |
D | Ambrożewicz 2018 [72] |
| Phospholip. LA (18:3) | ↓ | |||||
| Free AA (20:4) | ↓ | |||||
| Free DHA (22:6) | ↓ | |||||
| Long-chain fatty acids | ↑ | PsA (compared to Ps) | Serum | HPLC–HRMS (SPME) | D, M | Looby 2021 [65] |
| 1,11-Undecanedicarboxylic acid | ↑ | |||||
| Eicosanoids | ↑ | |||||
| 8-isoPGF2α | ↑ | PsA (compared to Ps) | Mononuclear cells | UPLC–TOF-MS | D, Pro | Wójcik 2019 [69] |
| 4-HNE | ↑ | |||||
| 4-HNE adducts | ↓ | |||||
| 15-d-PGJ2 | ↓ | |||||
| 15-HETE | ↓ | |||||
| Formic acid | ↓ | SLE (compared to RA) | Serum | 1H-NMR | D | Ouyang 2011 [29] |
* D, diagnostic; M, monitoring; Pre, predictive; Pro, prognostic; Re, response; Ri, risk; S, safety.