Homocysteine, antioxidant vitamins and lipids as biomarkers of neurodegeneration in Alzheimer’s disease versus non-Alzheimer’s dementia

Abstract

Introduction and objective. Evidence for the benefit of antioxidants' based therapeutic intervention in dementia are inconsistent. Parallel studies in disease forms of dementia different than Alzheimer's are even less conclusive. In this study, the role of serum levels of homocysteine (tHcy), lipids and antioxidants in predicting the risk of cognitive decline in Alzheimer's disease (AD) versus non-Alzheimer's dementias (n-AD). The objective was to add to the ongoing cumulative research to establish the biochemical baseline for potential nutri-therapeutic intervention in different forms of dementia. Materials and method. 65 participants with dementia (DP-s) were divided into two groups: ADP-patients with Alzheimer's disease and n-ADP-patients with dementia of a different etiology than primary neurodegenerative dementia in the course of Alzheimer's disease. Cognitive function was assessed by Mini-Mental State Examination (MMSE) and related to plasma levels of tHcy, folate, vitamins B-6, B-12, lipids and vitamins A and E for both groups. Also examined were associations between cognitive impairment and several variables (age, education, duration of dementia) that might confound nutrition-cognition associations. Results. A significant reduction in serum vitamin A levels and elevation of total cholesterol levels were shown for the DP-s group compared to those in the control group. Moreover, significant differences were found in MMSE data and serum vitamin E and tHcy levels between patients with ADP and n-ADP. The scores for MMSE showed a correlation with the vitamin E levels and duration of dementia in the ADP group and/or correlation with tHcy, levels of vitamins A and/or E, and duration of dementia in the n-ADP group. Conclusions. The results obtained suggest that elevated serum tHcy and decreased levels of vitamins A and E are associated with an increased risk of non-Alzheimer's dementias, although further studies involving a larger cohort are now needed to verify these results.

Blood-Based Biomarkers for Alzheimer’s Disease Diagnosis and Progression: An Overview

“…Hypovitaminosis is implicated in the pathogenesis of various disorders [ 334 , 335 ], and there is increasing evidence that vitamins also play a key role in neurodegenerative diseases, leading to hypotheses concerning their use as disease biomarkers [ 336 , 337 ]. Regarding AD, although preliminary data are certainly encouraging, and the role of vitamins as biomarkers for AD has been widely investigated in literature ( Table 3 ) [ 188 , 297 , 338 , 339 , 340 , 341 , 342 , 343 , 344 , 345 , 346 , 347 , 348 , 349 , 350 , 351 ], some limitations in terms of consistency, reproducibility, and specificity remain to be solved, and further research is needed before hypothesizing a clinical application.…”

“…Regarding vitamins A and E, while data from a cross-sectional study reported decreased blood concentrations of vitamin A in AD participants [ 351 ], in another study, serum deficiency of both vitamin A and E was correlated with cognitive impairment in patients with dementia other than Alzheimer’s [ 350 ], thus emphasizing that additional studies are required to better assess both the specificity and consistency of these potential biomarkers.…”

High-throughput and simultaneous quantitative analysis of homocysteine–methionine cycle metabolites and co-factors in blood plasma and cerebrospinal fluid by isotope dilution LC–MS/MS

“…For instance, an imbalance of this metabolic pathway, marked by hyperhomocysteinemia and/or an altered SAM/SAH ratio, is a hallmark of memory loss and cognitive decline in elderly populations [34, 35] This loss of metabolic homeostasis may result from deficiency in metabolites and co-factors—such as vitamin B 12 or folic acid—directly and indirectly involved in the methylation of homocysteine. An increased interest exists to decipher their role as potential biomarkers of neurodegeneration in Alzheimer’s disease [36–38]. The robustness of our method for the sensitive detection and quantitation of the 17 metabolites and co-factors of methionine metabolism was assessed in biological materials collected from healthy donors and patients diagnosed with Alzheimer’s disease.…”

Do low‐serum vitamin E levels increase the risk of Alzheimer disease in older people? Evidence from a meta‐analysis of case‐control studies

“…Finally, 121 additional papers failed to meet the inclusion criteria. Therefore, this selection resulted in 17 studies [5][6][7][8][13][14][15][16][17][18][19][20][21][22][23][24][25] that were identified to have as met the rigid inclusion criteria (Figure 1). Table 1 shows the basic characteristics of the selected studies included in this meta-analysis.…”