Research Article
Serum Metabolites as Potential Biomarkers for Diagnosis of Knee Osteoarthritis
Table 2
Significantly altered metabolites in serum of patients with mild or severe OA compared to that of healthy controls.
| | Metabolite | (/min) | (/) | Ion | Comparison | Related pathway | | OA versus HC | m-OA versus s-OA |
| 1 | 4-Oxoproline | 0.73 | 130.051 | [M + H]+ | *↓ | NS | Amino acid metabolism | 2 | L-Glycine | 0.78 | 120.030 | [M + FA − H]− | **↓ | *↓ | Amino acid metabolism | 3 | L-Histidine | 0.88 | 156.077 | [M + H]+ | **↓ | *↓ | Amino acid metabolism | 4 | Hypoxanthine | 0.91 | 135.031 | [M − H]− | **↑ | NS | Purine metabolism | 5 | Pyridoxine | 0.96 | 170.082 | [M + H]+ | *↓ | NS | Energy metabolism | 6 | Pyruvate | 1.02 | 133.014 | [M + FA−H]− | *↑ | NS | Glycolysis | 7 | Homocysteine | 1.09 | 136.043 | [M + H]+ | **↑ | NS | Energy metabolism | 8 | Urate | 1.16 | 169.035 | [M + H]+ | **↑ | NS | Purine metabolism | 9 | 3-Carboxy-4-methyl-2-oxopentanoate | 2.85 | 173.045 | [M − H]− | *↑ | NS | Amino acid metabolism | 10 | Methyl-hippuric acid | 3.11 | 194.082 | [M + H]+ | *↑ | NS | Amino acid metabolism | 11 | L-Tryptophan | 3.59 | 205.097 | [M + H]+ | **↑ | NS | Amino acid metabolism | 12 | Sphingomyelin (d18:1/16:0) | 6.09 | 703.575 | [M + H]+ | *↓ | NS | Sphingolipid metabolism | 13 | Propionyl-L-carnitine | 6.98 | 218.137 | [M + H]+ | *↓ | NS | Fatty acid metabolism | 14 | LPC (18:0) | 13.11 | 524.372 | [M + H]+ | **↓ | NS | Lipid metabolism |
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↑: increased; ↓: decreased; ; ; NS, not significant; m-OA, mild OA; s-OA, severe OA.
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