Plasma amino acid and urinary organic acid profiles in dementia

In our study, we examined routine biochemistry laboratory tests in patients with mild cognitive impairment and Alzheimer dementia, along with plasma amino acids and urinary organic acids. Total of 105 individuals were included in our study, consisting of 35 healthy controls, 35 with mild cognitive impairment, and 35 with Alzheimer dementia. Glutamine was found to be significantly lower in the mild cognitive impairment group compared to the control group (P = 0,041), while isoleucine and tryptophan were significantly higher (P = 0,012 and P = 0,043). In the Alzheimer's group, alanine, leucine, tryptophan, and valine were significantly higher compared to the control group (P = 0,049, P = 0,039, P = 0,003, and P = 0,042, respectively), whereas glutamic acid and glutamine were significantly lower (P = 0,015 and P = 0,017). Among urinary organic acids, lactic acid, pyruvic acid, and suberic acid were significantly higher in the Alzheimer's group compared to the control group (P = 0,026, P = 0,016, and P = 0,042, respectively), while homovanillic acid and succinic acid were found to be significantly lower (P = 0,022 and P = 0,005). In the index that distinguished healthy individuals from patients with mild cognitive impairment with 94% accuracy, cystine, tryptophan, glutamine, glutamic acid, alanine, MPV, and plateletcrit were used. In the index that separated healthy individuals from the Alzheimer's group with 91% accuracy, educational level, MPV, MCHC, plateletcrit, NEUT-GI, alanine, valine, and hydroxylysine were used. In the index that distinguished mild cognitive impairment patients from Alzheimer's patients with 91% accuracy, valine, lymphocytes, homocysteine, NEUT-GI, and homovanillic acid were used. These parameters and indices may serve as potential biomarkers for the diagnosis of both conditions and can be validated through multicenter prospective cohort studies.