Sciences and Sophisticated Diagnostics, University of Palermo, 90127 Palermo, Italy; [email protected] (G.B.); [email protected] (B.L.S.); [email protected]

February 23, 2023

Sciences and Sophisticated Diagnostics, University of Palermo, 90127 Palermo, Italy; [email protected] (G.B.); [email protected] (B.L.S.); [email protected] (C.M.G.); [email protected] (R.V.G.); [email protected] (C.S.); [email protected] (L.A.) Division of Laboratory Medicine, AOUP “P. Giaccone”, 90127 Palermo, Italy Correspondence: [email protected]: Bivona, G.; Lo Sasso, B.; Gambino, C.M.; Giglio, R.V.; Scazzone, C.; Agnello, L.; Ciaccio, M. The Function of Vitamin D as a Biomarker in Alzheimer’s Illness. Brain Sci. 2021, 11, 334. 10.3390/brainsci11030334 Academic Editor: Chiara Villa Received: 15 February 2021 Accepted: 2 March 2021 Published: 6 MarchAbstract: Vitamin D and VEGFR3/Flt-4 Purity & Documentation Cognition can be a common association, which led to a outstanding body of literature information in the past 50 years. The brain can synthesize, catabolize, and obtain Vitamin D, which has been proved to regulate a lot of cellular processes in neurons and microglia. Vitamin D aids synaptic plasticity and neurotransmission in dopaminergic neural circuits and exerts antiinflammatory and neuroprotective activities within the brain by decreasing the synthesis of proinflammatory cytokines along with the oxidative anxiety load. Additional, Vitamin D action within the brain has been connected towards the clearance of amyloid plaques, which represent a feature of Alzheimer Illness (AD), by the immune cell. Primarily based on these considerations, several research have investigated the function of circulating Vitamin D levels in individuals 5-HT5 Receptor Antagonist site impacted by a cognitive decline to assess Vitamin D’s eventual part as a biomarker or even a danger aspect in AD. An association in between low Vitamin D levels plus the onset and progression of AD has been reported, and some interventional studies to evaluate the part of Vitamin D in preventing AD onset have already been performed. Nevertheless, a lot of pitfalls impacted the research offered, such as substantial discrepancies inside the procedures used plus the lack of standardized data. Despite many studies, it remains unclear no matter whether Vitamin D can possess a role in cognitive decline and AD. This narrative review aims to answer two important queries: regardless of whether Vitamin D is usually utilized as a trusted tool for diagnosing, predicting prognosis and response to remedy in AD individuals, and no matter whether it’s a modifiable threat issue for stopping AD onset. Keyword phrases: Alzheimer’s Illness; Vitamin D; 25(OH)D levels; biomarker; Vitamin D deficiency1. Introduction If a single searches for the keywords and phrases “Vitamin D” and “Cognition” in, a single finds over 1000 articles which have been published with no break in continuity for the past 50 years. The concept of a doable hyperlink amongst Vitamin D metabolism and brain function has been successfully proposed then proved by a outstanding body of information. When assessing the Vitamin D circulating levels in Mild Cognitive Impairment and Alzheimer Illness (AD) patients, an association has but been located. Nevertheless, the attempt to work with Vitamin D as a biomarker of cognitive decline systematically failed and, additionally, Vitamin D supplementation in these individuals yielded controversial outcomes. Lots of factors can clarify this debacle. Initially, the research assessing Vitamin D levels and its serum biomarker 25(OH)D in AD sufferers have some limitations (diverse assay approaches; heterogeneity of Vitamin D cut-offs; discrepancies among the measures made use of to define the cognitive function), which sharply limit the robustness of findings accomplished. Second, discr.