Figure 1Volcano plot of metabolite profiles. The volcano plot was depicted as a log scaled axes of fold change (x-axis) and p-value (y-axis) for visualization. Metabolites with a significant difference (adjusted p < 0.05) are named in the plot. a = acyl; ae = acyl-alkyl; LPC = lysophosphatidylcholines; PC = phosphatidylcholines; SM = sphingomyelins.
Figure 2Comparison of pair-wise correlation coefficients of all of detected serum metabolites. Solid boxes indicate correlation coefficients (>0.9) of pairs of two metabolites. AA = amino acids; AC = acylcarnitines; BA = biogenic amines; LPC = lysophosphatidylcholines; PC = phosphatidylcholines; SM = sphingomyelins.
Table 1Changes in serum metabolite concentrations between young and aged mice.
Metabolite |
Younga
|
Ageda
|
Up or downb
|
p* |
AC
|
C14 |
0.09 ± 0.01 |
0.07 ± 0.01 |
↓ |
0.035 |
C16 |
0.24 ± 0.01 |
0.16 ± 0.02 |
↓ |
0.006 |
C18 |
0.06 ± 0.01 |
0.05 ± 0.01 |
↓ |
0.048 |
C18:1 |
0.21 ± 0.00 |
0.19 ± 0.00 |
↓ |
0.001 |
C2 |
26.88 ± 1.29 |
19.53 ± 1.75 |
↓ |
0.004 |
C5-OH |
0.10 ± 0.01 |
0.07 ± 0.01 |
↓ |
0.003 |
BA
|
Kynurenine |
0.89 ± 0.11 |
1.09 ± 0.05 |
↑ |
0.040 |
Sarcosine |
5.49 ± 0.62 |
3.29 ± 1.20 |
↓ |
0.048 |
Spermidine |
6.79 ± 0.85 |
3.61 ± 0.57 |
↓ |
0.006 |
Spermine |
1.05 ± 0.08 |
0.72 ± 0.06 |
↓ |
0.004 |
LPC
|
LPC a C16:0 |
424.54 ± 1.86 |
399.76 ± 13.25 |
↓ |
0.033 |
LPC a C24:0 |
0.73 ± 0.07 |
0.56 ± 0.06 |
↓ |
0.039 |
PC
|
PC aa C28:1 |
0.17 ± 0.01 |
0.22 ± 0.02 |
↑ |
0.017 |
PC aa C34:3 |
18.06 ± 0.30 |
20.08 ± 1.19 |
↑ |
0.046 |
PC aa C42:6 |
1.96 ± 0.03 |
1.40 ± 0.15 |
↓ |
0.004 |
PC ae C34:1 |
6.01 ± 0.21 |
5.18 ± 0.44 |
↓ |
0.042 |
PC ae C38:4 |
4.70 ± 0.47 |
5.78 ± 0.38 |
↑ |
0.037 |
PC ae C38:6 |
3.75 ± 0.12 |
3.03 ± 0.31 |
↓ |
0.020 |
PC ae C40:4 |
2.11 ± 0.12 |
2.76 ± 0.29 |
↑ |
0.024 |
PC ae C42:1 |
0.53 ± 0.10 |
0.75 ± 0.08 |
↑ |
0.040 |
SM
|
SM C16:1 |
6.15 ± 0.12 |
4.79 ± 0.78 |
↓ |
0.041 |
SM C18:0 |
3.21 ± 0.14 |
2.72 ± 0.18 |
↓ |
0.021 |
SM C24:0 |
14.34 ± 0.33 |
10.06 ± 1.44 |
↓ |
0.007 |
Table 2Top 10 ranked metabolites selected by biomarker identifier (BI) scores.
Metabolite |
BI score |
Glutamate |
275.9 |
Kynurenine |
195.3 |
LPC a C17:0 |
167.8 |
C0 |
159.3 |
PC ae C42:1 |
143.2 |
Spermidine |
135.5 |
PC ae C38:4 |
133.4 |
Sarcosine |
128.4 |
Hexose |
127.8 |
C14 |
125.1 |
Table 3Statistical selection of age-related metabolites.
Metabolite |
p* |
BI scorea
|
Adjusted p** |
AC
|
C0 |
NS |
159.3 |
NS |
C14 |
0.035 |
125.1 |
0.025 |
C5-OH |
0.003 |
123.4 |
0.036 |
AA
|
Glutamate |
NS |
275.9 |
0.019 |
BA
|
kyneurenine |
0.040 |
195.3 |
NS |
Sarcosine |
0.048 |
128.4 |
0.044 |
Spermidine |
0.006 |
135.5 |
0.041 |
LPC
|
LPC a C17:0 |
NS |
167.8 |
NS |
LPC a C24:0 |
0.039 |
112.4 |
0.002 |
PC
|
PC ae C38:4 |
0.037 |
133.4 |
0.001 |
PC ae C40:4 |
0.024 |
117.9 |
0.022 |
PC ae C42:1 |
0.040 |
143.2 |
0.005 |
SM
|
SM C24:0 |
0.007 |
120.8 |
0.013 |
Table 4Significant metabolite pairs between young and aged mice.
Ratio of pair metabolites |
Concentration ratio
|
p* |
Young |
Aged |
LPC a C24:0/PC ae C38:4 |
0.155 ± 0.002 |
0.097 ± 0.007 |
1.460E-04 |
PC ae C40:4/LPC a C24:0 |
2.916 ± 0.225 |
4.918 ± 0.006 |
1.044E-04 |