TABLE 5.
PC analysis1
| PC | Pathway (metabolites, n) | Metabolites within PCs | Eigenvalue | Variance explained, % | Cumulative variance, % |
| 1 | Amino acid and lipid (37) | Amino acid: α-hydroxybutyrate | 39.00 | 12.83 | 12.83 |
| Lipid: acetylcarnitine, 15-methylpalmitate, 17-methylstearate, hexadecanedioate, tetradecanedioate, 16-hydroxypalmitate, 3-hydroxydecanoate, 3-hydroxyoctanoate, glycerol, 3-hydroxybutyrate, 10-heptadecenoate, 10-nonadecenoate, arachidate, cis-vaccenate, eicosenoate, margarate, myristate, myristoleate, nonadecanoate, oleate, palmitate, palmitoleate, pentadecanoate, stearate, 5-dodecenoate, caprate, laurate, dihomo-linoleate, docosadienoate, docosahexaenoate, docosapentaenoate, docosapentaenoate, linoleate, linolenate, stearidonate | |||||
| 2 | Amino acid and lipid (14) | Amino acid: glutamate, glutamine, 5-oxoproline | 20.28 | 6.67 | 19.50 |
| Lipid: leukotriene B4, 13-HODE plus 9-HODE, glycerol 3-phosphate, 1-oleoylplasmenylethanolamine, 1-palmitoylplasmenylethanolamine, glycerophosphorylcholine, arachidonate, dihomo-linolenate, eicosapentaenoate, sphingosine, leucylleucine | |||||
| 3 | Lysolipid: GPCs (19) | Lysolipid: 1-arachidonoylglycerophosphocholine, 1-dihomo-linoleoylglycerophosphocholine, 1-docosahexaenoylglycerophosphocholine, 1-docosapentaenoylglycerophosphocholine, 1-eicosatrienoylglycerophosphocholine, 1-eicosenoylglycerophosphocholine, 1-linolenoylglycerophosphocholine, 1-linoleoylglycerophosphocholine, 1-margaroylglycerophosphocholine, 1-myristoylglycerophosphocholine, 1-oleoylglycerophosphocholine, 1-palmitoleoylglycerophosphocholine, 1-palmitoylglycerophosphocholine, 1-pentadecanoylglycerophosphocholine, 1-stearoylglycerophosphocholine, 2-linoleoylglycerophosphocholine, 2-oleoylglycerophosphocholine, 2-palmitoylglycerophosphocholine, 2-stearoylglycerophosphocholine | 15.90 | 5.23 | 24.73 |
| 4 | Steroid (12) | Steroid: 21-hydroxypregnenolone disulfate, 4-androsten-3β-17β-diol disulfate 1, 4-androsten-3β-17β-diol disulfate 2, 5α-androstan-3β-17β-diol disulfate, 5α-pregnan-3β-20α-diol disulfate, andro steroid monosulfate 2, androsterone sulfate, dehydroisoandrosterone sulfate, epiandrosterone sulfate, pregn steroid monosulfate, pregnen-diol disulfate, pregnenolone sulfate | 13.30 | 4.37 | 29.10 |
| 5 | γ-Glutamyl amino acid (7) | γ-Glutamyl amino acid: γ-glutamylglutamate, γ-glutamylisoleucine, γ-glutamylleucine, γ-glutamylmethionine, γ-glutamylphenylalanine, γ-glutamylvaline; Polypeptide: HWESASLLR | 10.51 | 3.46 | 32.56 |
| 6 | Amino acid: BCAAs and aromatic AAs (7) | Amino acid: isoleucine, leucine, lysine, methionine, phenylalanine, tyrosine, γ-glutamyltyrosine | 7.21 | 2.37 | 34.93 |
| 7 | Amino acid (3) | Amino acid: 3-methyl-2-oxobutyrate, 3-methyl-2-oxovalerate, 4-methyl-2-oxopentanoate | 6.35 | 2.09 | 37.02 |
| 8 | Lysolipid: GPEs (7) | Lysolipid: 1-eicosatrienoylglycerophosphoethanolamine, 1-linoleoylglycerophosphoethanolamine, 1-oleoylglycerophosphoethanolamine, 1-palmitoylglycerophosphoethanolamine, 1-stearoylglycerophosphoethanolamine, 2-oleoylglycerophosphoethanolamine, 2-palmitoylglycerophosphoethanolamine | 6.03 | 1.98 | 39.01 |
| 9 | Amino acid and TCA (7) | Amino acid: aspartate, isoleucylglycine, valylglycine, dimethylarginine, pro-hydroxy-pro, trans-4-hydroxyproline; TCA cycle: citrate | 5.06 | 1.67 | 40.67 |
| 10 | Amino acid (3) | Amino acid: asparagine, glycine, serine | 4.58 | 1.51 | 42.18 |
| 11 | Vitamin and lipid (5) | Vitamin: α-Tocopherol, 1-stearoylglycerol, palmitoyl sphingomyelin, stearoyl sphingomyelin, cholesterol | 4.47 | 1.47 | 43.65 |
| 12 | Amino acid: shorter-chain acylcarnitines (5) | Amino acid–acylcarnitines: 2-methylbutyrylcarnitine, isovalerylcarnitine Lipid: carnitine, butyrylcarnitine, propionylcarnitine | 4.31 | 1.42 | 45.07 |
| 13 | Amino acid, glycogen, vitamin, and nucleotide (5) | Amino acid: serotonin; glycogen metabolism: maltose, maltotriose; vitamin: nicotinamide; nucleotide: adenosine 5-monophosphate | 4.06 | 1.34 | 46.40 |
| 14 | Lipid: cholates (4) | Lipid: glycochenodeoxycholate, glycocholate, taurochenodeoxycholate, taurocholate | 3.49 | 1.15 | 47.55 |
| 15 | Peptide (5) | Peptide: glycylleucine, leucylalanine, leucylglycine, serylleucine, threonylleucine | 3.40 | 1.12 | 48.67 |
| 16 | Lipid, longer-chain acylcarnitines (5) | Lipid: cis-4-decenoyl carnitine, decanoylcarnitine, hexanoylcarnitine, laurylcarnitine, octanoylcarnitine | 3.17 | 1.04% | 49.71% |
| 17 | Lipid (4) | Lipid: azelate, sebacate, caproate, heptanoate | 3.03 | 1.00 | 50.71 |
| 18 | Amino acid (4) | Amino acid: isobutyrylcarnitine, p-cresol sulfate, phenylacetylglutamine, 3-indoxyl sulfate | 2.80 | 0.92 | 51.63 |
| 19 | Lysolipid: inositols (5) | Lysolipid: 1-arachidonoylglycerophosphoinositol, 1-oleoylglycerophosphoinositol, 1-palmitoylglycerophosphoinositol, 1-stearoylglycerophosphoinositol, 2-stearoylglycerophosphoinositol | 2.71 | 0.89 | 52.52 |
| 20 | Amino acid (3) | Amino acid: α-hydroxyisovalerate, 3-(4-hydroxyphenyl)lactate, indolelactate | 2.62 | 0.86 | 53.38 |
1
PC analysis was used to identify the top 20 PCs with eigenvalues >2.5 comprised of 161 metabolites with factor loading values with magnitudes ≥0.50. AA, amino acid; BCAA, branched-chain amino acid; GPC, glycerophosphocholine; GPE, glycerophosphoethanolamine; HODE, hydroxy-octadecadienoic acid; PC, principal component; TCA, tricarboxylic acid.