Table 1. OPLS-DA coefficients and their variable importance in projection (VIP) for significantly changed metabolites in serum.
Metabolites | Multi-criteria assessment (MCA)c | |||||||
No. | Names | δ 1H (ppm) | HFD vs. Normal | HFD+GAH vs. HFD | ||||
Coefficient valued | VIP | p valuee | Coefficient valued | VIP | p valuee | |||
Large macromolecules a | ||||||||
1 | HDL | 0.86 (m) | 0.974 | 5.59 | ↑, <0.001 | −0.777 | 5.18 | ↓, 0.001 |
2 | LDL | 0.88 (m) | 0.953 | 4.06 | ↑, <0.001 | −0.817 | 3.88 | ↓, 0.001 |
8 | Lipid | 1.28 (m) | 0.857 | 4.00 | ↑, <0.001 | −0.882 | 4.77 | ↓, <0.001 |
16 | N-acetyl-glycoprotein | 2.04 (s) | 0.882 | 2.36 | ↑, <0.001 | −0.840 | 2.50 | ↓, 0.001 |
17 | O-acetyl-glycoprotein | 2.14 (s) | −0.896 | 1.09 | ↓, <0.001 | 0.610 | 1.18 | ↑, 0.003 |
24 | PUFA | 2.75 (m) | 0.985 | 2.93 | ↑, <0.001 | −0.776 | 2.25 | ↓, 0.001 |
25 | Albumin | 3.02 | −0.947 | 1.43 | ↓, <0.001 | 0.776 | 1.39 | ↑, 0.002 |
29 | Phosphotidylcholine | 3.23 (s) | 0.904 | 4.52 | ↑, <0.001 | −0.860 | 5.85 | ↓, <0.001 |
36 | UFA | 5.29 (m) | 0.983 | 4.37 | ↑, <0.001 | −0.838 | 3.93 | ↓, <0.001 |
Small molecules b | ||||||||
3 | Isoleucine | 1.01 (d) | −0.915 | 1.56 | ↓, <0.001 | 0.744 | 1.14 | ↑, 0.031 |
4 | Leucine | 0.97 (t) | −0.732 | 2.07 | ↓, 0.001 | 0.713 | 1.83 | ↑, 0.001 |
5 | Valine | 1.04 (d) | −0.755 | 2.10 | ↓, <0.001 | 0.628 | 1.61 | ↑, 0.010 |
6 | Isobutyrate | 1.14 (d) | −0.681 | 0.92 | ↓, 0.003 | 0.605 | 1.15 | ↑, 0.008 |
7 | 3-hydroxybutyrate | 1.20 (d) | −0.507 | 2.18 | –, 0.113 | 0.584 | 5.24 | ↑, 0.017 |
9 | Lactate | 4.11 (q) | −0.683 | 2.10 | –, 0.285 | 0.601 | 2.77 | –, 0.124 |
10 | Alanine | 1.48 (d) | −0.585 | 1.93 | ↓, 0.013 | 0.519 | 1.76 | –, 0.067 |
11 | Lysine | 3.03 (t) | −0.815 | 1.19 | ↓, 0.001 | 0.791 | 1.87 | ↑, 0.001 |
12 | Arginine | 1.67 (m) | −0.701 | 0.98 | ↓, 0.003 | 0.711 | 0.99 | ↑, 0.003 |
13 | Ornithine | 3.06 (t) | −0.303 | 0.68 | –, 0.254 | 0.742 | 1.28 | ↑, 0.005 |
14 | Acetate | 1.92 (s) | −0.742 | 1.83 | ↓, 0.003 | 0.568 | 1.17 | –, 0.078 |
18 | Glutamate | 2.35 (t) | −0.843 | 1.21 | ↓, 0.003 | 0.834 | 1.45 | ↑, 0.006 |
19 | Glutamine | 2.45 (m) | −0.614 | 1.30 | ↓, <0.001 | 0.737 | 1.83 | ↑, 0.001 |
20 | Acetoacetate | 2.29 (s) | −0.591 | 1.23 | –, 0.051 | 0.664 | 2.50 | ↑, 0.005 |
21 | Pyruvate | 2.37 (s) | −0.818 | 1.48 | ↓, <0.001 | 0.646 | 1.47 | ↑, 0.031 |
23 | Citrate | 2.53 (d) | −0.786 | 1.31 | ↓, <0.001 | 0.492 | 0.71 | –, 0.136 |
32 | Betaine | 3.27 (s) | −0.774 | 2.87 | ↓, 0.001 | 0.623 | 2.21 | –, 0.128 |
35 | Glycine | 3.56 (s) | −0.722 | 2.93 | ↓, 0.001 | 0.737 | 3.34 | ↑, 0.004 |
38 | Tyrosine | 6.90 (d) | −0.775 | 0.70 | ↓, <0.001 | 0.811 | 0.92 | ↑, 0.002 |
39 | 1-Methylhistidine | 7.06 (s) | −0.760 | 0.69 | ↓, 0.001 | 0.779 | 0.65 | ↑, 0.003 |
40 | Phenylalanine | 7.33 (m) | −0.920 | 0.65 | ↓, <0.001 | 0.837 | 0.62 | ↑, 0.003 |
Coefficient values are calculated by LED-BPP coefficient-coded loadings plots.
Coefficient values are calculated by CPMG coefficient-coded loadings plots.
Multi-criteria assessment (MCA) was performed by followed criteria: 1. Coefficient value |r| >0.576, 2. VIP>1, 3. p value <0.05.
The coefficients from the OPLS-DA results; positive and negative signs indicate positive and negative correlations in the concentrations of serum metabolites.
Independent t test (two-tailed).
HDL: high-density lipoprotein; LDL: low-density lipoprotein; PUFA: Polyunsaturated fatty acids; UFA: unsaturated fatty acids.