TABLE 2.

Plasma energy metabolic substrates (lactate, pyruvate) oxidative stress marker malondialdehyde (MDA), amino acid precursors (AAPs) tyrosine (Tyr), tryptophan (Trp), methionine (Met), and phenylalanine (Phenyl-) of the study populations.

Variable	AD (N = 44)	FTD (N = 13)	VaD (N = 8)	MCI (N = 10)	CTRL (N = 15)	p	Post hoc
Energy metabolic substrates
Lactate (NV 0.4–2.0 μmol/mL)	1.65 ± 0.61	1.60 ± 0.54	1.87 ± 0.69	1.74 ± 0.50	1.38 ± 0.30	0.28
Pyruvate (NV 0.042–0.130 μmol/mL)	0.15 ± 0.06	0.17 ± 0.05	0.19 ± 0.07	0.14 ± 0.05	0.06 ± 0.03	<0.0001	A
Lactate/Pyruvate ratio	12.20 ± 5.93	9.81 ± 3.11	10.93 ± 5.01	13.65 ± 5.31	29.07 ± 16.48	<0.0001	B
Oxidative stress marker
Malondialdehyde (μmol/L)	10.80 ± 3.52	10.47 ± 2.83	13.38 ± 4.32	11.73 ± 2.70	3.62 ± 0.86	<0.0001	C
Amino acid precursors
Tyrosine (μmol/L)	53.5 ± 10.5	55.3 ± 14.4	58.0 ± 16.0	52.4 ± 15.3	53.4 ± 12.8	0.89
Tryptophan (μmol/L)	43.7 ± 8.5	44.9 ± 9.1	47.0 ± 12.0	47.8 ± 11.8	40.9 ± 6.5	0.49
Methionine (μmol/L)	–	–	–	–	–	–
Phenylalanine (μmol/L)	51.6 ± 9.0	55.4 ± 11.5	60.6 ± 11.3	53.4 ± 5.9	57.7 ± 9.7	0.10

Post hoc comparisons (Dunn-Sidak). A: AD vs. CTRL p < 0.0001; FTD vs. CTRL p < 0.0001; VaD vs. CTRL p < 0.0001; MCI vs. CTRL p = 0.002. B: AD vs. CTRL p < 0.0001; FTD vs. CTRL p < 0.0001; VaD vs. CTRL p < 0.0001; MCI vs. CTRL p = 0.0002. C: AD vs. CTRL p < 0.0001; FTD vs. CTRL p < 0.0001; VaD vs. CTRL p < 0.0001; MCI vs. CTRL p < 0.0001. AD, Alzheimer’s disease; FTD, frontotemporal dementia; VaD, vascular dementia; MCI, mild cognitive impairment; CTRL, control subjects; NV, normal values.