Mild Systemic Oxidative Stress in the Subclinical Stage of Alzheimer’s Disease

Abstract

Alzheimer's disease (AD) is a late-onset, progressive degenerative disorder that affects mainly the judgment, emotional stability, and memory domains. AD is the outcome of a complex interaction among several factors which are not fully understood yet; nevertheless, it is clear that oxidative stress and inflammatory pathways are among these factors. 65 elderly subjects (42 cognitively intact and 23 with probable Alzheimer's disease) were selected for this study. We evaluated erythrocyte activities of superoxide dismutase, catalase, and glutathione peroxidase as well as plasma levels of total glutathione, α-tocopherol, β-carotene, lycopene, and coenzyme Q10. These antioxidant parameters were confronted with plasmatic levels of protein and lipid oxidation products. Additionally, we measured basal expression of monocyte HLA-DR and CD-11b, as well as monocyte production of cytokines IL1-α, IL-6, and TNF-α. AD patients presented lower plasmatic levels of α-tocopherol when compared to control ones and also higher basal monocyte HLA-DR expression associated with higher IL-1α production when stimulated by LPS. These findings support the inflammatory theory of AD and point out that this disease is associated with a higher basal activation of circulating monocytes that may be a result of α-tocopherol stock depletion.

Neuroprotective mechanisms of astaxanthin: a potential therapeutic role in preserving cognitive function in age and neurodegeneration

“…In this study, plasma and erythrocyte levels of PLOOH were significantly decreased in both low-and high-dose groups compared to the control group. This finding maybe significant because it has been suggested that elevated erythrocyte membrane oxidation is associated with neurodegenerative diseases (Bosman et al 1991;Giavarotti et al 2013;Goodall et al 1994;Kawamoto et al 2005;Kawamoto et al 2013;Kosenko et al 2013).…”

Plasma Antioxidant Status in Patients with Alzheimer’s Disease and Cognitively Intact Elderly: A Meta-Analysis of Case-Control Studies

“…Pooled meta-analysis of seven studies with 424 AD patients and 319 cognitively intact controls showed that individuals with AD had 0.15 moles/l lower levels of lycopene (95% CI: -0.27, -0.02; P = 0.02; Table 1, Figure 2c) than cognitively intact controls. Individually, two studies reported lower plasma lycopene levels in AD cases [18][19] and five reported no difference [15,20,22,27,28]. Significant heterogeneity was observed among studies (I 2 = 95%, P < 0.00001).…”

“…Vitamin C 13 * Pooled analysis of the sixteen studies with 623 AD patients and 491 cognitively intact controls revealed lower plasma levels of Vitamin C in those with AD compared to non-demented controls (PMD -12.58 moles/l, 95% Cl -17.73, -7.43, P < 0.00001; Table 1, Figure 4b). Individually, nine studies reported significantly lower levels in patients with AD [15, 18-20, 27, 29, 31, 35, 38] while the remaining seven studies found no significant difference between groups [17,21,25,28,[36][37]39]. Significant heterogeneity was observed across studies (I 2 =95%, P < 0.00001) but sensitivity analysis failed to attribute this to a single study.…”

“…[15][16][17][18][19][20][21][22][24][25][26][27][28], lycopene (7 studies)[15, 18-20, 22, 27, 28], β-cryptoxanthin (4 studies)[18][19][20]22], lutein (5 studies) [18-20, 22-23], zeaxanthin (5 studies) [18-20, 22-23], vitamin A (15 studies) [15, 16, 18-21, 24, 26, 29-35], vitamin C (16 studies) [15, 17-21, 25, 27-29, 31, 35-39] vitamin E (31 studies) [15, 17-20, 24-35, 38-51] and uric acid (21 studies)[15, 18-20, 33, 42-43, 49, 52-63]. The summary results for each antioxidant are provided inTable 1.…”

Oxidative Stress in Neurodegenerative Diseases

“…Differences in results might be caused by measurement of antioxidants at different disease stages (fully developed disease vs. subclinical stage of the disease) [219][220][221].…”