Table 3.
Metabolites in plasma significantly differentiating between chronic neuropathic pain (NP) patients and healthy controls according to OPLS-DA.
| Metabolites | VIPpred | p (corr) | Controls intensity × 1000 median (min–max) | NP intensity × 1000 median (min–max) | p value | NP vs con |
|---|---|---|---|---|---|---|
| his_26 | 1.52 | − 0.74 | 140 (110–154) | 118 (89–153) | 0.004* | ↓ |
| NAAs + pro_313 | 1.47 | 0.72 | 502 (420–828) | 893 (422–1772) | 0.009* | ↑ |
| Unkn_358 | 1.45 | 0.71 | 1362 (848–2597) | 2880 (632–10,151) | 0.014* | ↑ |
| NAAs + pro_312 | 1.43 | 0.70 | 548 (367–801) | 860 (391–2228) | 0.016* | ↑ |
| his_9 | 1.42 | − 0.70 | 131 (101–153) | 115 (91–156) | 0.011* | ↓ |
| lipid/ffa_36 | 1.40 | 0.69 | 330 (234–687) | 710 (156–2162) | 0.023* | ↑ |
| Unkn_355 | 1.39 | 0.68 | 137 (118–166) | 167 (123–244) | 0.008* | ↑ |
| Unkn_347 | 1.35 | 0.66 | 83 (57–174) | 148 (47–548) | 0.041* | ↑ |
| Unkn_24 | 1.33 | 0.65 | 0 (0) | 18 (0–111) | 0.001* | ↑ |
| Unkn_11 | 1.33 | − 0.65 | 17 (13–19) | 14 (12–16) | 0.011* | ↓ |
| Unkn_25 | 1.32 | 0.65 | 0 (0) | 20 (0–120) | 0.001* | ↑ |
| NAAs + pro_309 | 1.32 | 0.64 | 385 (307–552) | 533 (335–949) | 0.026* | ↑ |
| Unkn_43 | 1.31 | 0.64 | 0 (0) | 5 (0–36) | 0.005* | ↑ |
| ser_86 | 1.31 | − 0.64 | 179 (125–269) | 153 (126–195) | 0.041* | ↓ |
| Unkn_354 | 1.30 | 0.64 | 164 (142–208) | 194 (143–285) | 0.029* | ↑ |
| Unkn_44 | 1.28 | 0.63 | 0 (0) | 6 (0–37) | 0.005* | ↑ |
| NAAs + pro_315 | 1.28 | 0.63 | 330 (256–474) | 416 (269–555) | 0.037* | ↑ |
| Unkn_82 | 1.28 | − 0.63 | 253 (207–305) | 212 (155–267) | 0.012* | ↓ |
| NAAs + pro_308 | 1.27 | 0.62 | 317 (239–411) | 399 (289–648) | 0.009* | ↑ |
| NAAs_310 | 1.27 | 0.62 | 1512 (1248–1835) | 1697 (1277–2422) | 0.02* | ↑ |
| Unkn_175 | 1.22 | 0.60 | 93 (83–116) | 110 (70–165) | 0.002* | ↑ |
| Unkn_215 | 1.21 | 0.59 | 121 (111–164) | 143 (116–165) | 0.002* | ↑ |
| Unkn_81 | 1.20 | − 0.59 | 279 (210–332) | 260 (166–289) | 0.114 | ↓ |
| Unkn_232 | 1.19 | 0.58 | 125 (99–147) | 139 (103–223) | 0.086 | ↑ |
| Unkn_353 | 1.18 | 0.58 | 182 (162–234) | 206 (164–290) | 0.033* | ↑ |
| gln_290 | 1.18 | 0.58 | 147 (125–167) | 164 (138–410) | 0.006* | ↑ |
| Unkn_230 | 1.17 | 0.57 | 75 (53–114) | 107 (41–251) | 0.210 | ↑ |
| NAAs + pro_305 | 1.17 | 0.57 | 175 (143–231) | 203 (166–243) | 0.007* | ↑ |
| NAAs + pro_316 | 1.16 | 0.57 | 222 (172–315) | 274 (180–356) | 0.043* | ↑ |
| gln_302 | 1.14 | 0.56 | 190 (173–213) | 205 (187–230) | 0.003* | ↑ |
| Unkn_373 | 1.13 | − 0.55 | 38 (33–66) | 35 (29–46) | 0.095 | ↓ |
| NAAs + pro_307 | 1.12 | 0.55 | 411 (318–494) | 448 (362–574) | 0.016* | ↑ |
| Unkn_352 | 1.12 | 0.55 | 132 (115–160) | 143 (120–184) | 0.033* | ↑ |
| myo-inositolcholine_76 | 1.11 | 0.55 | 82 (58–106) | 95 (78–132) | 0.005* | ↑ |
| pro + glu_271 | 1.11 | 0.54 | 74 (58–138) | 102 (75–130) | < .001* | ↑ |
| Unkn_216 | 1.11 | 0.54 | 103 (94–130) | 114 (102–136) | 0.004* | ↑ |
| 3-hydroxyisobutyrate or isobutyrate_372 | 1.11 | − 0.54 | 97 (69–299) | 74 (36–182) | 0.057 | ↓ |
| val_287 | 1.10 | 0.54 | 103 (78–147) | 114 (87–395) | 0.057 | ↑ |
| phe_19 | 1.10 | 0.54 | 26 (21–32) | 32 (25–107) | 0.004* | ↑ |
| Unkn_80 | 1.10 | − 0.54 | 206 (157–293) | 179 (154–253) | 0.086 | ↓ |
| Unkn_218 | 1.10 | − 0.54 | 115 (93–138) | 104 (94–112) | 0.114 | ↓ |
| ser_84 | 1.10 | − 0.54 | 294 (195–403) | 258 (198–339) | 0.07 | ↓ |
| NAAs + pro_317 | 1.09 | 0.54 | 163 (126–234) | 197 (128–265) | 0.041* | ↑ |
| gln + unkn_304 | 1.08 | 0.53 | 159 (131–177) | 171 (149–201) | 0.029* | ↑ |
| ethanol_362 | 1.06 | 0.52 | 99 (92–117) | 118 (97–183) | < .001* | ↑ |
| Unkn_56 | 1.06 | 0.52 | 88 (67–108) | 93 (82–157) | 0.104 | ↑ |
| 3-hydroxyisobutyrate or isobutyrate_370 | 1.05 | − 0.51 | 89 (64–291) | 72 (41–175) | 0.078 | ↓ |
| ser + mannose_87 | 1.04 | − 0.51 | 191 (141–267) | 169 (139–248) | 0.078 | ↓ |
| val_286 | 1.03 | 0.50 | 99 (76–127) | 111 (88–230) | 0.037* | ↓ |
| lys_213 | 1.03 | − 0.50 | 182 (138–277) | 175 (132–227) | 0.286 | ↓ |
The metabolites are listed in descending order for VIPpred. A negative p (corr) indicates lower levels in patients while a positive p(corr) indicates the opposite. The p-value is according to Mann–Whitney test and *Refers to statistically significant differences between controls and NP patients. Up or down regulation is reported in the column furthest to the right. His histidine, NAAs N-acetyl aspartate, Pro proline, Ser serine, Ffa free fatty acid, Unkn unknown, Lys lysine, Gln glutamate, val valine, phe phenylalanine.