Table 3.
Statistically significant metabolites with VIP >1 and FC <0.5 in women with FM relative to plasma samples of women in a comparison group
| Metabolite | Positive ion mode | Negative ion mode | Metabolic pathway | ||||
|---|---|---|---|---|---|---|---|
| VIP | FC | P value | VIP | FC | P value | ||
| Energy metabolism | |||||||
| 2‐Hydroxyglutarate | 1.65 | 0.30 | < 0.001 | 0.37 | 1.10 | 0.505 | Butanoate metabolism |
| Alpha‐ketoglutaric acid + 2h | – | – | – | 1.99 | 0.21 | < 0.001 | Citrate cycle |
| Pyruvate | – | – | – | 2.03 | 0.16 | < 0.001 | Glycolysis |
| Lipid metabolism | |||||||
| 3‐Hydroxykynurenine | 1.57 | 0.37 | < 0.001 | 1.47 | 0.40 | < 0.001 | – |
| 3‐Hydroxy‐3‐methylglutarate | – | – | – | 1.71 | 0.28 | <0.001 | Lipid metabolism |
| Azelaic acid | – | – | – | 1.53 | 0.42 | < 0.001 | – |
| Decanoate | – | – | – | 1.11 | 0.45 | 0.004 | Fatty acid biosynthesis |
| Amino acids | |||||||
| 4‐Coumarate | – | – | – | 1.51 | 0.27 | < 0.001 | Tyrosine metabolism |
| 3‐Methyl‐2‐oxovaleric acid | – | – | – | 1.56 | 0.24 | < 0.001 | Val/Leu/Ile biosynthesis |
| 4‐Methyl‐2‐oxo‐pentanoic acid | – | – | – | 1.56 | 0.20 | < 0.001 | Val/Leu/Ile biosynthesis |
| 4‐Hydroxy‐l‐phenylglycine | 1.29 | 0.31 | 0.005 | – | – | – | Cyanoamino acid metabolism |
| Cys‐gly | 2.03 | 0.04 | < 0.001 | – | – | – | Glutathione metabolism |
| Decanoylcarnitine | 1.23 | 0.49 | 0.007 | – | – | – | – |
| Homocysteine | 1.61 | 0.45 | < 0.001 | 1.48 | 0.42 | < 0.001 | Cysteine and methionine metabolism |
| L‐cysteine | 0.23 | 0.92 | 0.870 | 1.91 | 0.13 | < 0.001 | Cysteine and methionine metabolism |
| L‐cystine | 1.52 | 0.50 | < 0.001 | 1.86 | 0.20 | < 0.001 | Gly/Ser/Thr metabolism |
| L‐glutamine | 1.73 | 0.34 | < 0.001 | 1.54 | 0.29 | < 0.001 | Arginine biosynthesis |
| L‐methionine | 1.46 | 0.49 | 0.002 | 1.34 | 0.50 | 0.001 | Cysteine and methionine metabolism |
| N‐acetylputrescine | 1.57 | 0.40 | 0.001 | – | – | – | Arginine and proline metabolism |
| Unclassified | |||||||
| Ascorbic acid | – | – | – | 1.77 | 0.08 | < 0.001 | Ascorbate and aldarate metabolism |
| D‐saccharic acid | 2.22 | 0.16 | < 0.001 | 1.97 | 0.13 | < 0.001 | Ascorbate and aldarate metabolism |
| L‐methionine sulfoximine | – | – | – | 1.84 | 0.16 | < 0.001 | – |
| S‐carboxymethyl‐l‐cysteine | 1.89 | 0.28 | < 0.001 | 1.78 | 0.23 | < 0.001 | – |
FC, fold change; FM, fibromyalgia; Gly, glycine; Ile, isoleucine; Leu, leucine; Ser, serine; Thr, threonine; Val, valine; VIP, Variable Importance in Projection.
References used to pinpoint the pathway for each metabolite were the Human Metabolome Database30 (http://www.hmdb.ca/) and the Kyoto Encyclopedia of Genes and Genomes KEGG33 (https://www.genome.jp/kegg/).