Investigating carotenoid and α-tocopherol levels in preclinical Alzheimer's disease

Theoretical thesis.Bibliography: pages 55-63.1. Introduction -- 1.1 Pathology -- 1.1.1 Beta-Amyloid -- 1.1.2 Tau -- 1.1.3 Cerebral Amyloid Angiopathy -- 1.2 Types of AD -- 1.3 Signs and symptoms -- 1.4 Risk factors -- 1.4.1 Genetic risk factors -- 1.4.2 Cardiovascular risk factors -- 1.4.3 Modifiable factors -- 1.5 Diagnosis -- 1.5.1 Cerebrospinal fluid -- 1.5.2 Positron emission tomography -- 1.5.3 Magnetic Resonance Imaging -- 1.5.4 Blood biomarkers -- 1.6 Treatments -- 1.7 Oxidative stress and inflammation -- 1.8 Carotenoids -- 1.9 Vitamin E -- 1.10 Bioactivities -- 1.10.1 Antioxidant potential 1.10.2 Anti-inflammatory potential -- 1.10.3 Anti-amyloidogenic potential -- 1.11 Antioxidants and cognition -- 1.12 Aims -- 2. Methods -- 2.1 Participants -- 2.3 Neuroimaging -- 2.4 C-reactive protein measurement and APOE genotyping -- 2.5 Food frequency questionnaire and plasma carotenoid measurement -- 2.6 Inflammatory Marker assays -- 2.7 Plasma Aβ analysis -- 2.8 Neuropsychological and clinical assessments -- 2.9 Statistical analyses -- 3. Results -- 3.1 Participant demographics -- 3.2 Association of carotenoids and α-tocopherol with NAL: Plasma α-carotene is significantly higher, whereas plasma α-tocopherol is significantly lower in the preclinical AD group after adjusting for the study covariates -- 3.2.1 Intercorrelation significance varies between carotenoids and α-tocopherol -- 3.3 Associations between plasma carotenoid and α-tocopherol levels and dietary carotenoid and α-tocopherol levels: individual plasma carotenoids, except lycopene, were significantly positively associated with their respective dietary intakes -- 3.3.1 Dietary carotenoids and α-tocopherol were not significantly different between NAL groups -- 3.4 Association of carotenoids and α-tocopherol with plasma Aβ: plasma lutein and β-carotene were significantly associated with plasma Aβ -- 3.5 Associations of carotenoids and α-tocopherol with cognitive performance: -- 3.5.1 Higher α-tocopherol levels were significantly associated with better verbal, visual and episodic memory -- 3.5.2 Carotenoids and α-tocopherol were not significantly associated with working memory and executive function -- 3.5.3 Higher levels of lutein, β-carotene and α-tocopherol were associated with better global cognitive performance -- 3.6 Cytokine measurement and the association of carotenoids and α-tocopherol with inflammatory factors: cytokines were not significantly associated with carotenoids or α-tocopherol -- 3.7 Association of carotenoids and α-tocopherol with hippocampal volume: carotenoids and α-tocopherol were not significantly associated with hippocampal volume -- 4. Discussion -- 5. Conclusion -- 6. References -- AppendixOxidative stress, a well-documented contributor to neurodegeneration, has been shown to be an early feature of Alzheimer's disease (AD) and may have preclinical significance. Carotenoids and vitamins have been proposed to have antioxidant, anti-inflammatory and anti-amyloidogenic potentials, which interrupts the oxidative stress pathway, protecting against neurodegeneration. The protective effect of these biomolecules has been reported in cognitive decline and AD progression, however, it has not yet been investigated in cognitively normal individuals at higher risk for AD, in relation to amyloid-β. This study investigates whether there is an association between plasma carotenoids and α-tocopherol levels, and neocortical amyloid-β load (NAL) prior to the onset of clinical AD.1 online resource ( viii, 54 pages) colour illustrations, graphs, tables, chart