Table 2.
Differences in plasma amino acid levels (µmol/L) in control subjects (C-NNDS), malnourished patients with Alzheimer’s disease (AD) (MNA Group 1), AD patients at risk of malnutrition (MNA Group 2), and normonourished AD patients (MNA Group 3). The table shows that the 3-nutritionally stratified AD subgroups, compared to C-NNDS, had 3 altered AAs in common: aspartic acid, taurine, and 3-methyl-histidine.
| Amino Acids | C-NNDS (N = 17) |
AD Patients MNA Group 1 (N = 8) |
AD Patients MNA Group 2 (N = 18) |
AD Patients MNA Group 3 (N = 28) |
p Value |
|---|---|---|---|---|---|
| Aspartic acid | 27.86 ± 4.34 | 8.88 ± 5.59 † | 7.17 ± 2.79 ‡ | 8.86 ± 6.80 ‡ | <0.0001 |
| Glutamic acid | 107.74 ± 52.29 | 64.63 ± 19.18 | 60.33 ± 17.32 † | 68.68 ± 17.70 | 0.008 |
| Histidine | 60.22 ± 35.79 | 69.63 ± 8.93 | 67.17 ± 13.29 | 71.39 ± 14.14 ^ | 0.025 |
| Asparagine | 50.99 ± 14.84 | 40.25 ± 4.30 | 39.33 ± 6.54 ^ | 42.71 ± 6.51 | 0.015 |
| Serine | 130.79 ± 27.39 | 102.13 ± 19.75 | 96.56 ± 22.57 † | 110.00 ± 48.16 † | 0.0009 |
| Glutamine | 488.95 ± 75.61 | 515.00 ± 82.56 | 499.72 ± 83.32 | 511.07 ± 82.65 | 0.86 |
| 3-methyl-histidine | 0.87 ± 0.39 | 3.25 ± 1.97 † | 3.66 ± 1.98 ‡ | 3.88 ± 1.30 ‡ | <0.0001 |
| Arginine | 64.40 ± 19.60 | 71.75 ± 16.44 | 63.89 ± 24.23 | 63.79 ± 22.33 | 0.62 |
| Citrulline | 39.22 ± 7.33 | 35.88 ± 9.80 | 33.44 ± 8.94 | 35.32 ± 11.75 | 0.15 |
| Glycine | 224.84 ± 61.68 | 234.88 ± 38.80 | 246.11 ± 93.85 | 232.79 ± 81.78 | 0.81 |
| Threonine | 129.30 ± 42.21 | 125.88 ± 23.14 | 116.56 ± 28.67 | 118.07 ± 28.58 | 0.80 |
| Alanine | 370.89 ± 79.26 | 321.50 ± 39.71 | 371.67 ± 91.31 | 344.14 ± 74.21 | 0.29 |
| Taurine | 106.93 ± 32.71 | 82.25 ± 71.18 † | 71.72 ± 25.77 ^ | 64.39 ± 15.10 ‡ | <0.0001 |
| Tyrosine | 59.21 ± 17.61 | 53.50 ± 11.95 | 54.00 ± 13.56 | 53.21 ± 12.47 | 0.65 |
| Tryptophan | 47.23 ± 12.37 | 42.13 ± 11.10 | 44.22 ± 10.80 | 46.11 ± 8.36 | 0.47 |
| Phenylalanine | 61.32 ± 24.76 | 59.63 ± 23.54 | 52.78 ± 11.31 | 53.11 ± 10.19 | 0.67 |
| Isoleucine | 61.37 ± 14.60 | 57.38 ± 14.19 | 54.17 ± 20.55 | 60.00 ± 14.70 | 0.45 |
| Leucine | 122.37 ± 25.25 | 105.38 ± 35.32 | 102.28 ± 30.76 | 116.79 ± 24.39 | 0.08 |
| Lysine | 162.26 ± 35.02 | 219.25 ± 59.62 | 195.17 ± 44.17 | 205.21 ± 28.65 † | 0.003 |
| Valine | 246.49 ± 53.63 | 205.48 ± 68.88 | 199.44 ± 59.98 ^ | 227.73 ± 47.55 | 0.046 |
| TAAs | 2581.83 ± 263.18 | 2428.11 ± 365.33 | 2387.83 ± 424.43 | 2446.96 ± 308.65 | 0.27 |
| BCAAs | 430.23 ± 82.36 | 368.23 ± 117.08 | 355.89 ± 110.57 | 404.52 ± 84.87 | 0.061 |
| EAAs | 891.43 ± 137.92 | 887.98 ± 223.29 | 835.44 ± 196.77 | 902.29 ± 145.03 | 0.45 |
| EAAs/TAAs | 0.34 ± 0.03 | 0.36 ± 0.04 | 0.35 ± 0.03 | 0.37 ± 0.02 | 0.033 |
| BCAAs/TAAs | 0.17 ± 0.02 | 0.15 ± 0.03 | 0.15 ± 0.03 | 0.16 ± 0.02 | 0.036 |
| BCAAs/EAAs | 0.48 ± 0.05 | 0.41 ± 0.04 † | 0.42 ± 0.04 † | 0.45 ± 0.03 | <0.0001 |
^: p < 0.05 vs. C-NNDS; †: p < 0.01 vs. C-NNDS; ‡: p < 0.0001 vs. C-NNDS. Data are expressed as mean ± standard deviation. Reported p values are for between-group comparisons (Kruskal–Wallis test). False discovery rate was controlled at 5% by the Benjamini–Hochberg method. Significant differences were followed up by post-hoc paired comparisons (Dunn–Sidak test). Abbreviations: MNA, mini Nutritional assessment; TAAs, total amino acids; BCAAs, branched chain amino acids; EAAs, essential amino acids.