Altered Levels of Homocysteine and Serum Natural Antioxidants Links Oxidative Damage to Alzheimer's Disease

Cankurtaran, Mustafa; Yeşil, Yusuf; Kuyumcu, Mehmet Emin; Öztürk, Zeynel Abidin; Yavuz, Burcu Balam; Halil, Meltem; Ülger, Zekeriya; Cankurtaran, Eylem Şahin; Arıoğul, Servet

doi:10.3233/jad-2012-121630

Cited by 56 publications

(52 citation statements)

References 52 publications

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“…Among those 24 studies, 21 were case-control studies comparing serum uric acid levels in Alzheimer's disease patients with healthy controls [14-24, 28-32, 36-40] and 3 studies were cohort studies assessing risk of Alzheimer's disease in individuals with various categories of serum uric acid levels [33][34][35]. Among those 24 studies, 19 studies were published in English [14][15][16][17][18][19][20][21][22][23][24][28][29][30][31][32][33][34][35] while the other 5 studies were published in Chinese [36][37][38][39][40]. Those 21 case-control studies included a total of 1128 cases of Alzheimer's disease and 2498 controls without Alzheimer's disease [14-24, 28-32, 36-40].…”

Section: Characteristics Of Included Studiesmentioning

confidence: 98%

“…Of the remaining 35 studies, 6 studies were excluded for irrelevant outcomes and 5 studies were excluded for no usable data. Thus, 24 studies were finally included into the meta-analysis [14][15][16][17][18][19][20][21][22][23][24][28][29][30][31][32][33][34][35][36][37][38][39][40]. Among those 24 studies, 21 were case-control studies comparing serum uric acid levels in Alzheimer's disease patients with healthy controls [14-24, 28-32, 36-40] and 3 studies were cohort studies assessing risk of Alzheimer's disease in individuals with various categories of serum uric acid levels [33][34][35].…”

Section: Characteristics Of Included Studiesmentioning

confidence: 99%

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Inverse Association Between Serum Uric Acid Levels and Alzheimer’s Disease Risk

Hou

et al. 2015

Mol Neurobiol

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The association between Alzheimer's disease and uric acid levels had gained great interest in recent years, but there was still lack of definite evidence. A systematic review and meta-analysis of relevant studies was performed to comprehensively estimate the association. Relevant studies published before October 26, 2014, were searched in PubMed, Embase, and China Biology Medicine (CBM) databases. Study-specific data were combined using random-effects or fixed-effects models of meta-analysis according to between-study heterogeneity. Twenty-four studies (21 case-control and 3 cohort studies) were finally included into the meta-analysis. Those 21 case-control studies included a total of 1128 cases of Alzheimer's disease and 2498 controls without Alzheimer's disease. Those 3 cohort studies included a total of 7327 participants. Meta-analysis showed that patients with Alzheimer's disease had lower levels of uric acid than healthy controls (weighted mean difference (WMD) = -0.77 mg/dl, 95% CI -2.28 to -0.36, P = 0.0002). High serum uric acid levels were significantly associated with decreased risk of Alzheimer's disease (risk ratio (RR) = 0.66, 95% CI 0.52-0.85, P = 0.001). There was low risk of publication bias in the meta-analysis. There is an inverse association between serum uric acid levels and Alzheimer's disease. High serum uric acid level is a protective factor of Alzheimer's disease.

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Section: Characteristics Of Included Studiesmentioning

confidence: 98%

Section: Characteristics Of Included Studiesmentioning

confidence: 99%

Inverse Association Between Serum Uric Acid Levels and Alzheimer’s Disease Risk

Hou

et al. 2015

Mol Neurobiol

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“…In addition, some studies suggest that patients with higher serum UA levels have a markedly lower risk of progressing from impaired cognitive function to dementia [37], [38], while some studies found that even mild elevation of UA might enhance the risk of cognitive decline in older adults [39]. Other study revealed that patients with normal cognitive function have higher serum UA levels than AD patients [40]. Considering these inconsistent possibilities, we tried to establish what consensus could be reached from various studies by examining the change of serum UA levels in AD patients compared to healthy controls with meta-analytic techniques.…”

Section: Introductionmentioning

confidence: 99%

Serum Uric Acid Levels in Patients with Alzheimer's Disease: A Meta-Analysis

et al. 2014

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BackgroundSerum uric acid (UA) could exert neuro-protective effects against Alzheimer's disease (AD) via its antioxidant capacities. Many studies investigated serum UA levels in AD patients, but to date, results from these observational studies are conflicting.MethodsWe conducted a meta-analysis to compare serum UA levels between AD patients and healthy controls by the random-effects model. Studies were identified by searching PubMed, ISI Web of Science, EMBASE, and the Cochrane library databases from 1966 through July 2013 using the Medical Subject Headings and keywords without restriction in languages. Only case-control studies were included if they had data on serum UA levels in AD patients and healthy controls. Begg's funnel plot and Egger's regression test were applied to assess the potential publication bias. Sensitivity analyses and meta-regression were conducted to explore possible explanations for heterogeneity.ResultsA total of 11 studies met the inclusion criteria including 2708 participants were abstracted. Serum UA levels were not significantly different in AD patients compared to healthy controls (standardized mean difference (SMD) = −0.50; 95% confidence interval (CI): −1.23 to 0.22). Little evidence of publication bias was observed. Sensitivity analyses showed that the combined SMD was consistent every time omitting any one study, except only one study which greatly influenced the overall results. Meta-regression showed that year of publication, race, sample size, and mean age were not significant sources of heterogeneity.ConclusionOur meta-analysis of case-control studies suggests that serum UA levels do not differ significantly in AD patients, but there may be a trend toward decreased UA in AD after an appropriate interpretation. More well-designed investigations are needed to demonstrate the potential change of serum UA levels in AD patients.

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“…This effect manifests through an improvement in oxidative stress and other peripheral markers of dementia that show a significantly better state when both entities are present. [30][31][32][33] In 2009, this hypothesis arose from a basic study that increased our understanding of the protection offered by diabetes against Alzheimer disease. In this study of mature hippocampal neurons, researchers observed that loss of insulin receptors and poor diffusion of related ligands was mitigated and normalised by the action of insulin.…”

Section: Antidiabetic Drugs and Their Link To Alzheimer Diseasementioning

confidence: 98%

Alzheimer disease and cognitive impairment associated with diabetes mellitus type 2: associations and a hypothesis

Domínguez

Pagano

Marschoff

et al. 2014

Neurología (English Edition)

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Introduction: Epidemiological studies have demonstrated that patients with diabetes mellitus have an increased risk of developing Alzheimer disease, but the relationship between the 2 entities is not clear. Development:Both diseases exhibit similar metabolic abnormalities: disordered glucose metabolism, abnormal insulin receptor signalling and insulin resistance, oxidative stress, and structural abnormalities in proteins and ␤-amyloid deposits. Different hypotheses have emerged from experimental work in the last two decades. One of the most comprehensive relates the microvascular damage in diabetic polyneuritis with the central nervous system changes occurring in Alzheimer disease. Another hypothesis considers that cognitive impairment in both diabetes and Alzheimer disease is linked to a state of systemic oxidative stress. Recently, attenuation of cognitive impairment and normalisation of values in biochemical markers for oxidative stress were found in patients with Alzheimer disease and concomitant diabetes. Antidiabetic drugs may have a beneficial effect on glycolysis and its end products, and on other metabolic alterations.ଝ Please cite this article as: Domínguez RO, Pagano MA, Marschoff ER, González SE, Repetto MG, Serra JA. Enfermedad de Alzheimer y deterioro cognitivo asociado a la diabetes mellitus de tipo 2: relaciones e hipótesis. Neurología.

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Altered Levels of Homocysteine and Serum Natural Antioxidants Links Oxidative Damage to Alzheimer's Disease

Cited by 56 publications

References 52 publications

Inverse Association Between Serum Uric Acid Levels and Alzheimer’s Disease Risk

Inverse Association Between Serum Uric Acid Levels and Alzheimer’s Disease Risk

Serum Uric Acid Levels in Patients with Alzheimer's Disease: A Meta-Analysis

Alzheimer disease and cognitive impairment associated with diabetes mellitus type 2: associations and a hypothesis

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