Lipids' peroxidation markers in Alzheimer's disease and vascular dementia

Mechanisms of mitophagy and oxidative stress in cerebral ischemia-reperfusion, vascular dementia, and Alzheimer's disease

Neurological diseases have consistently represented a significant challenge in both clinical treatment and scientific research. As research has progressed, the significance of mitochondria in the pathogenesis and progression of neurological diseases has become increasingly prominent. Mitochondria serve not only as a source of energy, but also as regulators of cellular growth and death. Both oxidative stress and mitophagy are intimately associated with mitochondria, and there is mounting evidence that mitophagy and oxidative stress exert a pivotal regulatory influence on the pathogenesis of neurological diseases. In recent years, there has been a notable rise in the prevalence of cerebral ischemia/reperfusion injury (CI/RI), vascular dementia (VaD), and Alzheimer's disease (AD), which collectively represent a significant public health concern. Reduced levels of mitophagy have been observed in CI/RI, VaD and AD. The improvement of associated pathology has been demonstrated through the increase of mitophagy levels. CI/RI results in cerebral tissue ischemia and hypoxia, which causes oxidative stress, disruption of the blood-brain barrier (BBB) and damage to the cerebral vasculature. The BBB disruption and cerebral vascular injury may induce or exacerbate VaD to some extent. In addition, inadequate cerebral perfusion due to vascular injury or altered function may exacerbate the accumulation of amyloid β (Aβ) thereby contributing to or exacerbating AD pathology. Intravenous tissue plasminogen activator (tPA; alteplase) and endovascular thrombectomy are effective treatments for stroke. However, there is a narrow window of opportunity for the administration of tPA and thrombectomy, which results in a markedly elevated incidence of disability among patients with CI/RI. It is regrettable that there are currently no there are still no specific drugs for VaD and AD. Despite the availability of the U.S. Food and Drug Administration (FDA)-approved clinical first-line drugs for AD, including memantine, donepezil hydrochloride, and galantamine, these agents do not fundamentally block the pathological process of AD. In this paper, we undertake a review of the mechanisms of mitophagy and oxidative stress in neurological disorders, a summary of the clinical trials conducted in recent years, and a proposal for a new strategy for targeted treatment of neurological disorders based on both mitophagy and oxidative stress.

Hepatopancreatic metabolic disorders and their implications in the development of Alzheimer's disease and vascular dementia

Dementia has been faced with significant public health challenges and economic burdens that urges the need to develop safe and effective interventions. In recent years, an increasing number of studies have focused on the relationship between dementia and liver and pancreatic metabolic disorders that result in diseases such as diabetes, obesity, hypertension and dyslipidemia. Previous reports have shown that there is a plausible correlation between pathologies caused by hepatopancreatic dysfunctions and dementia. Glucose, insulin and IGF-1 metabolized in the liver and pancreas probably have an important influence on the pathophysiology of the most common dementias: Alzheimer's and vascular dementia. This current review highlights recent studies aimed at identifying convergent mechanisms, such as insulin resistance and other diseases, linked to altered hepatic and pancreatic metabolism, which are capable of causing brain changes that ultimately lead to dementia.

Physical and cellular impact of environmentally relevant microplastic exposure on thermally challenged Pocillopora damicornis (Cnidaria, Scleractinia)

Microplastic pollution is an increasing threat to coral reefs, which are already strongly challenged by climate change-related heat stress. Although it is known that scleractinian corals can ingest microplastic, little is known about their egestion and how microplastic exposure may impair corals at physiological and cellular levels. In addition, the effects of microplastic pollution at current environmental concentration have been little investigated to date, particularly in corals already impacted by heat stress. In this study, the combined effects of these environmental threats on Pocillopora damicornis were investigated from a physical and cellular perspective. Colonies were exposed to three concentrations of polyethylene microplastic beads (no microplastic beads: [No MP], 1 mg/L: [Low MP]; 10 mg/L: [High MP]), and two different temperatures (25 °C and 30 °C) for 72 h. No visual signs of stress in corals, such as abnormal mucus production and polyp extroflection, were recorded. At [Low MP], beads adhered to colonies were ingested but were also egested. Moreover, thermally stressed colonies showed a lower adhesion and higher egestion of microplastic beads. Coral bleaching was observed with an increase in temperature and microplastic bead concentration, as indicated by a general decrease in chlorophyll concentration and Symbiodiniaceae density. An increase in lipid peroxidation was measured in colonies exposed to [Low MP] and [High MP] and an up-regulation of stress response gene hsp70 was observed due to the synergistic interaction of both stressors. Overall, our findings showed that heat stress still represents the main threat to P. damicornis, while the effect of microplastics on coral health and physiology may be minor, especially at control temperature. However, microplastics could exacerbate the effect of thermal stress on cellular homeostasis, even at [Low MP]. While reducing ocean warming is critical for preserving coral reefs, effective management of emerging threats like microplastic pollution is equally essential.

Physical and social environmental enrichment alleviate ferroptosis and inflammation with inhibition of TLR4/MyD88/p38MAPK pathway in chronic cerebral hypoperfusion rats

A typical enriched environment (EE), which combines physical activity and social interaction, has been proven to mitigate cognitive impairment caused by chronic cerebral hypoperfusion (CCH). However, it remains unclear how the different components of EE promote cognitive recovery after CCH. This study stripped out the different components of EE into physical environmental enrichment (PE) and social environmental enrichment (SE), and compared the neuroprotective effects of PE, SE and typical EE (PSE) in CCH. The results of novel object recognition and Morris water maze tests showed that PE, SE, and PSE improved cognitive function in CCH rats. Additionally, Nissl and TUNEL staining revealed that three EEs reduced neuronal loss in the hippocampus. PSE exhibited superior neuroprotective and functional improvement effects compared to PE and SE, while there was no significant difference between PE and SE. Furthermore, three EEs reduced lipid peroxidation in the hippocampus with decreasing the levels of MDA and increasing the activities of SOD and GSH. The expression of SLC7A11 and GPX4 was increased, while the level of p53 was reduced in three EEs. This suggested that three EEs inhibited ferroptosis by maintaining the redox homeostasis in the hippocampus. Three EEs reduced the levels of IL-β, TNF-α, and IL-6, thereby inhibiting neuroinflammation. Additionally, Western blotting and immunofluorescence results indicated that three EEs also inhibited the TLR4/MyD88/p38MAPK signaling pathway. These findings collectively demonstrated that the three EEs alleviated hippocampal ferroptosis and neuroinflammation in CCH rats, thereby reducing neuronal loss, which might be associated with the inhibition of the TLR4/MyD88/p38MAPK signaling pathway. Moreover, the study results supported that it is only through the combination of physical exercise and social interaction that the optimal neuroprotective effects can be achieved. These findings provided valuable insights for the prevention and treatment of vascular cognitive impairment.

Molecular biomarkers for vascular cognitive impairment and dementia

As disease-specific interventions for dementia are being developed, the ability to identify the underlying pathology and dementia subtypes is increasingly important. Vascular cognitive impairment and dementia (VCID) is the second most common cause of dementia after Alzheimer disease, but progress in identifying molecular biomarkers for accurate diagnosis of VCID has been relatively limited. In this Review, we examine the roles of large and small vessel disease in VCID, considering the underlying pathophysiological processes that lead to vascular brain injury, including atherosclerosis, arteriolosclerosis, ischaemic injury, haemorrhage, hypoperfusion, endothelial dysfunction, blood-brain barrier breakdown, inflammation, oxidative stress, hypoxia, and neuronal and glial degeneration. We consider the key molecules in these processes, including proteins and peptides, metabolites, lipids and circulating RNA, and consider their potential as molecular biomarkers alone and in combination. We also discuss the challenges in translating the promise of these biomarkers into clinical application.

Insight into the potential role of ferroptosis in neurodegenerative diseases

Ferroptosis is a newly discovered way of programmed cell death, mainly caused by the accumulation of iron-dependent lipid peroxides in cells, which is morphologically, biochemically and genetically different from the previously reported apoptosis, necrosis and autophagy. Studies have found that ferroptosis plays a key role in the occurrence and development of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and vascular dementia, which suggest that ferroptosis may be involved in regulating the progression of neurodegenerative diseases. At present, on the underlying mechanism of ferroptosis in neurodegenerative diseases is still unclear, and relevant research is urgently needed to clarify the regulatory mechanism and provide the possibility for the development of agents targeting ferroptosis. This review focused on the regulatory mechanism of ferroptosis and its various effects in neurodegenerative diseases, in order to provide reference for the research on ferroptosis in neurodegenerative diseases.

Gastrodin Ameliorates Cognitive Dysfunction in Vascular Dementia Rats by Suppressing Ferroptosis via the Regulation of the Nrf2/Keap1-GPx4 Signaling Pathway

Gastrodia elata Bl. has a long edible history and is considered an important functional food raw material. Gastrodin (GAS) is one of the main functional substances in G. elata BI. and can be used as a health care product for the elderly to enhance resistance and delay aging. This study investigated the ameliorative effect and mechanism of GAS on cognitive dysfunction in vascular dementia (VaD) rats, which provides a theoretical basis for development and utilization of functional food. The water maze test shows that GAS improves learning and memory impairment in VaD rats. Meanwhile; GAS significantly decreased the levels of Fe²⁺ and malondialdehyde (MDA); increased the content of glutathione (GSH); and significantly up-regulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and glutathione peroxidase 4 (GPx4), the key regulatory factors of ferroptosis; while it down-regulated the expression of kelch-like ECH-associated protein (Keap1) and cyclooxygenase 2 (COX2). However, GAS does not directly regulate GPx4 and COX2 to inhibit ferroptosis. Furthermore, compared with GAS alone, GAS combined with Bardoxolone (an agonist of Nrf2) did not further affect the increase in GPx4 levels and decrease in COX2 levels, nor did it further affect the regulation of GAS on the biochemical parameters of ferroptosis in HT22 hypoxia injury. These findings revealed that GAS inhibited ferroptosis in hippocampal neurons by activating the Nrf2/Keap1-GPx4 signaling pathway, suggesting its possible application as a functional food for improving vascular dementia by inhibiting ferroptosis.

Effects of Selenium Supplementation in Patients with Mild Cognitive Impairment or Alzheimer's Disease: A Systematic Review and Meta-Analysis

Elevated levels of oxidative stress could cause and aggravate Alzheimer’s disease (AD). Selenium (Se) is a trace element with antioxidant and anti-inflammatory activity with neuroprotective effects. To evaluate the effects of Se supplementation in patients with AD or mild cognitive impairment (MCI) through a systematic review and meta-analysis, data were searched and collected from four electronic databases, including clinical trial studies published until December 2020, following the PRISMA guidelines. Statistical analysis was performed by RevMan, and the risk of bias was assessed using the Rob 2 tool. A total of 1350 scientific papers were collected, and following evaluation 11 papers were included in the systematic review and 6 of these were used in the meta-analysis. Studies that evaluated only Se supplementation observed an improvement in Se levels, glutathione peroxidase (GPX) activity, and in some cognitive tests in MCI patients; similarly, improvement in Se levels and mini-mental score was also observed in AD patients. Regarding supplementation of Se plus other nutrients, improvement in cognitive tests was observed in both AD and MCI patients. Therefore, Se supplementation is a good alternative for patients with AD and MCI for improving Se levels and GPX activity. More detailed studies are required to further evaluate the effects of Se on the cognitive deficit and oxidative stress associated with AD and MCI.

Effects of a Short-Term Lipopolysaccharides Challenge on Mouse Brain and Liver Peroxisomal Antioxidant and β-oxidative Functions: Protective Action of Argan Oil

During sepsis, the imbalance between oxidative insult and body antioxidant response causes the dysfunction of organs, including the brain and liver. Exposing mice to bacterial lipopolysaccharides (LPS) results in a similar pathophysiological outcome. The protection offered by argan oil was studied against LPS-induced oxidative stress, dysregulation of peroxisomal antioxidants, and β-oxidation activities in the brain and liver. In a short-term LPS treatment, lipid peroxidation (malonaldehyde assay) increased in the brain and liver with upregulations of proinflammatory tumor necrosis factor (Tnf)-α and anti-inflammatory interleukin (Il)-10 genes, especially in the liver. Although exposure to olive oil (OO), colza oil (CO), and argan oil (AO) prevented LPS-induced lipid peroxidation in the brain and liver, only AO exposure protected against liver inflammation. Remarkably, only exposure to AO prevented LPS-dependent glutathione (GSH) dysregulation in the brain and liver. Furthermore, exposure to AO increased more efficiently than OO and CO in both organs, peroxisomal antioxidant capacity via induction of catalase (Cat) gene, protein and activity expression levels, and superoxide dismutase (Sod1) mRNA and activity levels. Interestingly, LPS decreased protein levels of the peroxisomal fatty acid-ATP binding cassette (ABC) transporters, ABCD1 and ABCD2, and increased acyl-CoA oxidase 1 (ACOX1) protein expression. Moreover, these LPS effects were attenuated for ABCD1 and ACOX1 in the brain of mice pretreated with AO. Our data collectively highlight the protective effects of AO against early oxidative stress caused by LPS in the brain and liver and their reliance on the preservation of peroxisomal functions, including antioxidant and β-oxidation activities, making AO a promising candidate for the prevention and management of sepsis.

Association of Circulating Magnesium Levels in Patients With Alzheimer's Disease From 1991 to 2021: A Systematic Review and Meta-Analysis

Alzheimer's disease (AD) remains a medical and social challenge worldwide. Magnesium (Mg) is one of the most frequently evaluated essential minerals with diverse biological functions in human body. However, the association between circulating Mg levels and AD remains controversial. We conducted a meta-analysis of 21 studies published between 1991 and 2021 to determine whether the Mg levels in the blood and cerebrospinal fluid (CSF) are abnormal in AD. Literatures were searched in PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang Data without language limitations. A pooled subject sample including 1,112 AD patients and 1,001 healthy controls (HCs) was available to assess Mg levels in serum and plasma; 284 AD patients and 117 HCs were included for Mg levels in CSF. It was found that serum and plasma levels of Mg were significantly reduced in AD patients compared with HCs (standardized mean difference [SMD] = -0.89; 95% confidence interval [CI] [-1.36, -0.43]; P = 0.000). There was statistically non-significant for Mg level in CSF between AD and HCs, whereas a decreased tendency were detected (SMD = -0.16; 95% CI [-0.50, 0.18]; P = 0.364). .In addition, when we analyzed the Mg levels of serum, plasma and CSF together, the circulating Mg levels in AD patients was significantly lower (SMD = -0.74, 95% CI [-1.13; -0.35]; P = 0.000). These results indicate that Mg deficiency may be a risk factor of AD and Mg supplementation may be a potentially valuable adjunctive treatment for AD. Systematic Review Registration: www.crd.york.ac.uk/PROSPERO/, registration number CRD42021254557.

The role of inflammasomes in vascular cognitive impairment

There is an increasing prevalence of Vascular Cognitive Impairment (VCI) worldwide, and several studies have suggested that Chronic Cerebral Hypoperfusion (CCH) plays a critical role in disease onset and progression. However, there is a limited understanding of the underlying pathophysiology of VCI, especially in relation to CCH. Neuroinflammation is a significant contributor in the progression of VCI as increased systemic levels of the proinflammatory cytokine interleukin-1β (IL-1β) has been extensively reported in VCI patients. Recently it has been established that CCH can activate the inflammasome signaling pathways, involving NLRP3 and AIM2 inflammasomes that critically regulate IL-1β production. Given that neuroinflammation is an early event in VCI, it is important that we understand its molecular and cellular mechanisms to enable development of disease-modifying treatments to reduce the structural brain damage and cognitive deficits that are observed clinically in the elderly. Hence, this review aims to provide a comprehensive insight into the molecular and cellular mechanisms involved in the pathogenesis of CCH-induced inflammasome signaling in VCI.

The Emerging Scenario of the Gut-Brain Axis: The Therapeutic Actions of the New Actor Kefir against Neurodegenerative Diseases

The fact that millions of people worldwide suffer from Alzheimer’s disease (AD) or Parkinson’s disease (PD), the two most prevalent neurodegenerative diseases (NDs), has been a permanent challenge to science. New tools were developed over the past two decades and were immediately incorporated into routines in many laboratories, but the most valuable scientific contribution was the “waking up” of the gut microbiota. Disturbances in the gut microbiota, such as an imbalance in the beneficial/pathogenic effects and a decrease in diversity, can result in the passage of undesired chemicals and cells to the systemic circulation. Recently, the potential effect of probiotics on restoring/preserving the microbiota was also evaluated regarding important metabolite and vitamin production, pathogen exclusion, immune system maturation, and intestinal mucosal barrier integrity. Therefore, the focus of the present review is to discuss the available data and conclude what has been accomplished over the past two decades. This perspective fosters program development of the next steps that are necessary to obtain confirmation through clinical trials on the magnitude of the effects of kefir in large samples.

Therapeutic Potential of Remote Ischemic Conditioning in Vascular Cognitive Impairment

Vascular cognitive impairment (VCI) is a heterogeneous disease caused by a variety of cerebrovascular diseases. Patients with VCI often present with slower cognitive processing speed and poor executive function, which affects their independence in daily life, thus increasing social burden. Remote ischemic conditioning (RIC) is a non-invasive and efficient intervention that triggers endogenous protective mechanisms to generate neuroprotection. Over the past decades, evidence from basic and clinical research has shown that RIC is promising for the treatment of VCI. To further our understanding of RIC and improve the management of VCI, we summarize the evidence on the therapeutic potential of RIC in relation to the risk factors and pathobiologies of VCI, including reducing the risk of recurrent stroke, decreasing high blood pressure, improving cerebral blood flow, restoring white matter integrity, protecting the neurovascular unit, attenuating oxidative stress, and inhibiting the inflammatory response.

Role of Monoamine Oxidase Activity in Alzheimer's Disease: An Insight into the Therapeutic Potential of Inhibitors

Despite not being utilized as considerably as other antidepressants in the therapy of depression, the monoamine oxidase inhibitors (MAOIs) proceed to hold a place in neurodegeneration and to have a somewhat broad spectrum in respect of the treatment of neurological and psychiatric conditions. Preclinical and clinical studies on MAOIs have been developing in recent times, especially on account of rousing discoveries manifesting that these drugs possess neuroprotective activities. The altered brain levels of monoamine neurotransmitters due to monoamine oxidase (MAO) are directly associated with various neuropsychiatric conditions like Alzheimer’s disease (AD). Activated MAO induces the amyloid-beta (Aβ) deposition via abnormal cleavage of the amyloid precursor protein (APP). Additionally, activated MAO contributes to the generation of neurofibrillary tangles and cognitive impairment due to neuronal loss. No matter the attention of researchers on the participation of MAOIs in neuroprotection has been on monoamine oxidase-B (MAO-B) inhibitors, there is a developing frame of proof indicating that monoamine oxidase-A (MAO-A) inhibitors may also play a role in neuroprotection. The therapeutic potential of MAOIs alongside the complete understanding of the enzyme’s physiology may lead to the future advancement of these drugs.

Overview of the Neuroprotective Effects of the MAO-Inhibiting Antidepressant Phenelzine

Phenelzine (PLZ) is a monoamine oxidase (MAO)-inhibiting antidepressant with anxiolytic properties. This multifaceted drug has a number of pharmacological and neurochemical effects in addition to inhibition of MAO, and findings on these effects have contributed to a body of evidence indicating that PLZ also has neuroprotective/neurorescue properties. These attributes are reviewed in this paper and include catabolism to the active metabolite β-phenylethylidenehydrazine (PEH) and effects of PLZ and PEH on the GABA-glutamate balance in brain, sequestration of reactive aldehydes, and inhibition of primary amine oxidase. Also discussed are the encouraging findings of the effects of PLZ in animal models of stroke, spinal cord injury, traumatic brain injury, and multiple sclerosis, as well other actions such as reduction of nitrative stress, reduction of the effects of a toxin on dopaminergic neurons, potential anticonvulsant actions, and effects on brain-derived neurotrophic factor, neural cell adhesion molecules, an anti-apoptotic factor, and brain levels of ornithine and N-acetylamino acids.

Cholesterol, Atherosclerosis, and APOE in Vascular Contributions to Cognitive Impairment and Dementia (VCID): Potential Mechanisms and Therapy

Vascular contributions to cognitive impairment and dementia (VCID) are a common cause of cognitive decline, yet limited therapies exist. This cerebrovascular disease results in neurodegeneration via acute, chronic, local, and systemic mechanisms. The etiology of VCID is complex, with a significant impact from atherosclerosis. Risk factors including hypercholesterolemia and hypertension promote intracranial atherosclerotic disease and carotid artery stenosis (CAS), which disrupt cerebral blood flow and trigger ischemic strokes and VCID. Apolipoprotein E (APOE) is a cholesterol and phospholipid carrier present in plasma and various tissues. APOE is implicated in dyslipidemia and Alzheimer disease (AD); however, its connection with VCID is less understood. Few experimental models for VCID exist, so much of the present information has been drawn from clinical studies. Here, we review the literature with a focus on the clinical aspects of atherosclerotic cerebrovascular disease and build a working model for the pathogenesis of VCID. We describe potential intermediate steps in this model, linking cholesterol, atherosclerosis, and APOE with VCID. APOE4 is a minor isoform of APOE that promotes lipid dyshomeostasis in astrocytes and microglia, leading to chronic neuroinflammation. APOE4 disturbs lipid homeostasis in macrophages and smooth muscle cells, thus exacerbating systemic inflammation and promoting atherosclerotic plaque formation. Additionally, APOE4 may contribute to stromal activation of endothelial cells and pericytes that disturb the blood-brain barrier (BBB). These and other risk factors together lead to chronic inflammation, atherosclerosis, VCID, and neurodegeneration. Finally, we discuss potential cholesterol metabolism based approaches for future VCID treatment.

Alzheimer's disease improved through the activity of mitochondrial chain complexes and their gene expression in rats by boswellic acid

The foremost neurodegenerative disease is Alzheimer's (AD), which is characterized as a gradual decrease in memory, cognitive function, and also personal changes occurred. This study aims to assess the role of boswellic bioactive component in control Alzheimer's disease through enhancing mitochondrial electron transport chain complexes in the rat model. Rats were divided into five equal groups: the control group (G1), boswellic acid control group (G2), AD disease group (G3), boswellic acid -pre-treated group (G4) and boswellic acid-treated group (G5). At the end of the experiment, blood glucose level, tau protein, different neurochemicals parameters (dopamine, acetylcholine), L-malondialdehyde (MDA) levels, and superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities was determined. Also, GLUT2 and mitochondrial electron transport chain complexes were evaluated. As a result, an increase in hippocampus glucose, tau protein expression, MDA and GLUT2 in the AD group (G3) compared to control groups (G1 and G2) has been recorded. These parameters were declined after pre (G4) and treated (G5) by boswellic acid. The neurochemicals, antioxidants parameters, four mitochondrial chain complexes activities and their gene expression in the hippocampus of the AD group were decreased compared to the control groups (G1 and G2). In contrast, pre and treated groups by boswellic acid (G4 and G5, respectively) have shown an increase in antioxidants parameters, and the activities of four mitochondrial complexes, with the best improvement in the pre-treated group (G4), then treated group (G5). In conclusion; the boswellic acid improved the antioxidant and mitochondrial complexes in Alzheimer's disease.

Dimethyl fumarate attenuates 2-VO-induced vascular dementia via activating the Nrf2 signaling pathway in rats

BACKGROUND

Chronic cerebral hypoperfusion (CCH) induced oxidative stress and inflammation is known to be implicated in the pathogenesis of vascular dementia. The nuclear factor erythroid 2-related factor 2 (Nrf2) has emerged as a potential therapeutic target for neuroprotection. In the present study, we investigated the beneficial effects of dimethyl fumarate (DMF), an Nrf2 activator in an experimental model of vascular dementia.

METHODS

Permanent occlusion of the bilateral common carotid arteries (2-VO) was performed to induce CCH in adult male Sprague-Dawley rats. DMF (15, 30, and 60 mg/kg) was administered for 4 weeks. Cognitive performance was assessed using the Morris water maze (MWM) and novel object (NOR) tests. After behavior tests, various oxidative and inflammatory markers were assessed in the hippocampus.

RESULTS

The obtained results indicate that treatment with DMF significantly improved 2 VO-induced cognitive deficits. DMF decreased MDA (p < 0.001), protein carbonyl (PCO) contents (p < 0.001), and acetylcholinesterase (p < 0.01) activities, and inhibited inflammatory markers (TNF-α, IL-1β, NF-κβ, and COX-2) levels. Furthermore, our results showed that DMF augmented GSH (p < 0.001) levels and SOD (p < 0.05), CAT, and GSH-Px (p < 0.001) activities in the hippocampus. Nrf2 (p < 0.05) and its downstream targets HO-1 levels (p < 0.01) and NQO1 (p < 0.05) levels were also up-regulated after DMF treatment.

CONCLUSION

Taken together, the results demonstrate that DMF could serve as a promising neuroprotective agent for treating vascular dementia.

Astaxanthin protects cognitive function of vascular dementia

OBJECTIVE

The purpose of this study was to evaluate the effect of astaxanthin (AST) on cognition function, inflammatory response and oxidative stress in vascular dementia (VD) mice.

METHOD

VD mice model was established by left unilateral common carotid arteries occlusion (LUCCAO). Following LUCCAO, AST was intragastrically administered for 30 days. Object recognition test and morris water maze test were used to evaluate cognitive function. Hematoxylin and eosin staining was performed to observe the hippocampal neuron structure. Enzyme-linked immunosorbent assay kit and bicinchoninic acid kit were respectively adopted to measure IL-1β and IL-4 protein expression and superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in hippocampus and prefrontal cortex.

RESULTS

AST improved the discrimination ability of VD mice. The escape latency and path length of VD mice treated with AST were dramatically reduced. Besides, AST 200 mg/kg enhanced crossing platform time and the number of times crossing the platform quadrant, and alleviated the morphological impairment in VD mice. Moreover, we found that AST inhibited IL-1β expression and MDA content, whereas promoted IL-4 expression and SOD activity in a dose-dependent manner.

CONCLUSION

AST could improve cognitive impairment and hippocampal neurons in VD mice, which may be related to suppression of inflammatory response and oxidative stress.

Clinical Utility of Plasma Lipid Peroxidation Biomarkers in Alzheimer's Disease Differential Diagnosis

BACKGROUND

Differential diagnosis of Alzheimer's disease (AD) is a complex task due to the clinical similarity among neurodegenerative diseases. Previous studies showed the role of lipid peroxidation in early AD development. However, the clinical validation of potential specific biomarkers in minimally invasive samples constitutes a great challenge in early AD diagnosis.

METHODS

Plasma samples from participants classified into AD (n = 138), non-AD (including MCI and other dementias not due to AD) (n = 70) and healthy (n = 50) were analysed. Lipid peroxidation compounds (isoprostanes, isofurans, neuroprostanes, neurofurans) were determined by ultra-performance liquid chromatography coupled with tandem mass spectrometry. Statistical analysis for biomarkers' clinical validation was based on Elastic Net.

RESULTS

A two-step diagnosis model was developed from plasma lipid peroxidation products to diagnose early AD specifically, and a bootstrap validated AUC of 0.74 was obtained.

CONCLUSION

A promising AD differential diagnosis model was developed. It was clinically validated as a screening test. However, further external validation is required before clinical application.

Impact of ApoE Polymorphism and Physical Activity on Plasma Antioxidant Capability and Erythrocyte Membranes

The allele epsilon 4 (ε4) of apolipoprotein E (ApoE) is the strongest genetic risk factor for Alzheimer's disease (AD). ApoE protein plays a pivotal role in the synthesis and metabolism of amyloid beta (Aβ), the major component of the extracellular plaques that constitute AD pathological hallmarks. Regular exercise is an important preventive/therapeutic tool in aging and AD. Nevertheless, the impact of physical exercise on the well-being of erythrocytes, a good model of oxidative stress and neurodegenerative processes, remains to be investigated, particularly depending on ApoE polymorphism. Herein, we evaluate the oxidative status, Aβ levels, and the membrane's composition of erythrocytes in a cohort of human subjects. In our hands, the plasma antioxidant capability (AOC), erythrocytes membrane fluidity, and the amount of phosphatidylcholine (PC) were demonstrated to be significantly decreased in the ApoE ε4 genotype and non-active subjects. In contrast, erythrocyte Aβ content and lipid peroxidation increased in ε4 carriers. Regular physical exercise was associated with an increased plasma AOC and membrane fluidity, as well as to a reduced amount of erythrocytes Aβ. Altogether, these data highlight the influence of the ApoE genotype on erythrocytes' well-being and confirm the positive impact of regular physical exercise.

Effects of resveratrol on learning and memory in rats with vascular dementia

The purpose of the present study was to study the effects of resveratrol on cognitive function in rats with vascular dementia and to investigate the molecular mechanisms of its neuroprotective effects. Forty-five SD rats were randomly divided into 3 groups: The control group (Con group, n=15), the model group (VD group, n=15) and the resveratrol-treated VD group (Res group, n=15). The VD rats (the VD group and the Res group) were generated by bilateral common carotid artery occlusion. The rats in the Res group received daily resveratrol treatment intraperitoneally for 4 weeks. Cognitive function was tested using the Morris water maze test. The levels of SOD and MDA (oxidative stress indicators) were detected by ELISA kits. The protein expression of Bax, Bcl-2 and caspase-3 was detected by western blotting. Compared with the rats in the Con group, the rats in the VD group exhibited decreased cognitive function, significantly increased hippocampal content of MDA, Bax and caspase-3 (P<0.05), and significantly reduced hippocampal expression of SOD and Bcl-2 (P<0.05). Compared with the rats in the VD group, the rats in the Res group exhibited increased cognitive ability, reduced hippocampal content of MDA, Bax and caspase-3 (P<0.05), and increased hippocampal expression of SOD and Bcl-2 (P<0.05). Resveratrol treatment significantly improved the spatial learning and memory of the VD rats. The mechanism associated with the neuroprotective effects of resveratrol may be closely related to the inhibition of the apoptosis pathway and oxidative stress injury.

The Emerging Roles of Ferroptosis in Vascular Cognitive Impairment

Vascular cognitive impairment (VCI) is a clinical syndrome that encompasses all forms of cognitive deficits caused by cerebrovascular disease, from mild cognitive impairment to dementia. Vascular dementia, the second most common type of dementia after Alzheimer’s disease (AD), accounts for approximately 20% of dementia patients. Ferroptosis is a recently defined iron-dependent form of cell death, which is distinct from apoptosis, necrosis, autophagy, and other forms of cell death. Emerging evidence suggests that ferroptosis has significant implications in neurological diseases such as stroke, traumatic brain injury, and AD. Additionally, ferroptosis inhibition has an obvious neuroprotective effect and ameliorates cognitive impairment in various animal models. Here, we summarize the underlying mechanisms of ferroptosis and review the close relationship between ferroptosis and VCI.

Vitamin E and Alzheimer's disease: what do we know so far?

Vitamin E has been proposed as a potential clinical intervention for Alzheimer's disease (AD) given the plausibility of its various biological functions in influencing the neurodegenerative processes associated with the condition. The tocopherol and tocotrienol isoforms of vitamin E have multiple properties including potent antioxidant and anti-inflammatory characteristics, in addition to influences on immune function, cellular signalling and lowering cholesterol. Several of these roles offer a theoretical rationale for providing benefit for the treatment of AD-associated pathology. Diminished circulating concentrations of vitamin E have been demonstrated in individuals with AD. Reduced plasma levels have furthermore been associated with an increased risk of AD development while intake, particularly from dietary sources, may limit or reduce the rate of disease progression. This benefit may be linked to synergistic actions between vitamin E isoforms and other micronutrients. Nevertheless, randomised trials have found limited and inconsistent evidence of vitamin E supplementation as an effective clinical intervention. Thus, despite a strong rationale in support of a beneficial role for vitamin E for the treatment of AD, the evidence remains inconclusive. Several factors may partly explain this discrepancy and represent the difficulties of translating complex laboratory evidence and dietary interactions into clinical interventions. Methodological design limitations of existing randomised trials and restrictions to supplementation with a single vitamin E isoform may also limit the influence of effect. Moreover, several factors influence individual responsiveness to vitamin E intake and recent findings suggest variation in the underlying genetic architecture attenuates vitamin E biological availability and activity which likely contributes to the variation in clinical responsiveness and the failure of randomised trials to date. Importantly, the clinical safety of vitamin E remains controversial and warrants further investigation.

Decoding the Role of Platelets and Related MicroRNAs in Aging and Neurodegenerative Disorders

Platelets are anucleate cells that circulate in blood and are essential components of the hemostatic system. During aging, platelet numbers decrease and their aggregation capacity is reduced. Platelet dysfunctions associated with aging can be linked to molecular alterations affecting several cellular systems that include cytoskeleton rearrangements, signal transduction, vesicular trafficking, and protein degradation. Age platelets may adopt a phenotype characterized by robust secretion of extracellular vesicles that could in turn account for about 70-90% of blood circulating vesicles. Interestingly these extracellular vesicles are loaded with messenger RNAs and microRNAs that may have a profound impact on protein physiology at the systems level. Age platelet dysfunction is also associated with accumulation of reactive oxygen species. Thereby understanding the mechanisms of aging in platelets as well as their age-dependent dysfunctions may be of interest when evaluating the contribution of aging to the onset of age-dependent pathologies, such as those affecting the nervous system. In this review we summarize the findings that link platelet dysfunctions to neurodegenerative diseases including Alzheimer's Disease, Parkinson's Disease, Multiple Sclerosis, Huntington's Disease, and Amyotrophic Lateral Sclerosis. We discuss the role of platelets as drivers of protein dysfunctions observed in these pathologies, their association with aging and the potential clinical significance of platelets, and related miRNAs, as peripheral biomarkers for diagnosis and prognosis of neurodegenerative diseases.

Triptolide Improves Cognitive Dysfunction in Rats with Vascular Dementia by Activating the SIRT1/PGC-1α Signaling Pathway

Tripterygium Wilfordii Hook F has been exploited as a treatment for several diseases due to its neuroprotective, anti-tumor, and anti-inflammatory effects. Triptolide is one of its key bioactive compounds. Currently, the role of triptolide in cognitive dysfunction remains unclear. Here, the role of triptolide on cognitive dysfunction was investigated using chronic cerebral hypoperfusion-induced vascular dementia (VD) rat model. SD rats were administrated with Triptolide (5 μg/kg) for 6 weeks after undergoing permanent bilateral common carotid artery occlusion. The results show that triptolide treatment conferred neuroprotective effects in VD rats. Intraperitoneal injection of triptolide attenuated oxidative stress, learning and memory deficits, and neuronal apoptosis in the hippocampi. Moreover, triptolide enhanced the expression of SIRT1, PGC-1α, ZO-1, Claudin-5, and decreased the serum levels of NSE and S100B significantly. It also improved CCH-induced learning and memory deficits, and this is attributed to its capacity to promote SIRT1/PGC-1α signaling, confer antioxidant effects, and inhibit neuronal apoptosis. These findings indicate that triptolide may be an effective therapeutic agent for vascular cognitive dysfunction.

Emerging molecular mechanisms of vascular dementia

PURPOSE OF REVIEW

Microvascular ischemic disease of the brain is a common cause of cognitive impairment and dementia, particularly in the context of preexisting cardiovascular risk factors and aging. This review summarizes our current understanding of the emerging molecular themes that underlie progressive and irreparable vascular disease leading to neuronal tissue injury and dementia.

RECENT FINDINGS

Cardiometabolic risk factors including diabetes and hypertension are known to contribute to vascular disease. Currently, the impact of these risk factors on the integrity and function of the brain vasculature has been target of intense investigation. Molecularly, the consequences associated with these risk factors indicate that reactive oxygen species are strong contributors to cerebrovascular dysfunction and injury. In addition, genetic linkage analyses have identified penetrant monogenic causes of vascular dementia. Finally, recent reports begun to uncover a large number of polymorphisms associated with a higher risk for cerebrovascular disease.

SUMMARY

A comprehensive picture of key risk factors and genetic predispositions that contribute to brain microvascular disease and result in vascular dementia is starting to emerge. Understanding their relationships and cross-interactions will significantly aid in the development of preventive and intervention strategies for this devastating condition.

Protective effect of troxerutin and cerebroprotein hydrolysate injection on cerebral ischemia through inhibition of oxidative stress and promotion of angiogenesis in rats

Brain ischemia, including cerebral ischemia and cerebrovascular ischemia, leads to poor oxygen supply or cerebral hypoxia, and causes brain tissue death or cerebral infarction/ischemic stroke. The troxerutin and cerebroprotein hydrolysate injection (TCHI), is widely applied in China to improve blood supply in ischemic brain tissues and to enhance neuroprotective effects in clinical practice. However, the benefits and detailed underlying mechanism elaborating the effectiveness of TCHI in cerebrovascular diseases require further investigation. Therefore, in the present study, experimental in vivo and in vitro models were employed to investigate the potential mechanisms of TCHI on cerebral ischemic injury. The results demonstrated that TCHI increased the lactate dehydrogenase levels in the brain homogenate and conversely decreased lactic acid levels. TCHI was further observed to significantly increase superoxide dismutase activity and decrease malondialdehyde levels in ischemic brain tissues. In addition, TCHI significantly induced vascular maturation processes, including proliferation, adhesion, migration and tube formation in cultured human umbilical vein endothelial cells. Additionally, TCHI significantly stimulated microvessel formation in the rat aortic ring and chick chorioallantoic membrane assays. Taken together, these results provided strong evidence that TCHI stimulated angiogenesis at multiple steps, and indicated that TCHI attenuated cerebral ischemic damage through the amelioration of oxidative stress and promotion of angiogenesis.

Kaempferol attenuates cognitive deficit via regulating oxidative stress and neuroinflammation in an ovariectomized rat model of sporadic dementia

Alzheimer's disease (AD) is associated with oxidative stress, and ultimately results in cognitive deficit. Despite existing literature on the pathophysiology of AD, there is currently no cure for AD. The present study investigated the effects of kaempferol (Kmp) isolated from the extract of Mespilus germanica L. (medlar) leaves on cognitive impairment, hippocampal antioxidants, apoptosis, lipid peroxidation and neuro-inflammation markers in ovariectomized (OVX) rat models of sporadic AD. Kaempferol, as the main flavonoid of medlar extract has been previously known for anti-oxidative, anti-inflammatory and anti-neurotoxic effects. Thirty-two female Wistar rats were ovariectomized, and randomly divided into four groups: sham, OVX + saline, OVX + streptozotocin (STZ) + saline, OVX + STZ + Kmp. Animals received intracerebroventricular injection of STZ (3 mg/kg, twice with one day interval) to establish models of sporadic AD. Intraperitoneal injection of Kmp (10 mg/kg) for 21 days was performed in the OVX + STZ + Kmp group. Spatial learning and memory of rats were evaluated using a Morris water maze. Finally, brain homogenates were used for biochemical analysis by enzyme-linked immunosorbent assay. The results showed a significant improvement in spatial learning and memory as evidenced by shortened escape latency and searching distance in Morris water maze in the OVX + STZ + Kmp group compared with the OVX + STZ group. Kmp also exhibited significant elevations in brain levels of antioxidant enzymes of superoxide dismutase and glutathione, while reduction in tumor necrosis factor-α and malondialdehyde. Our results demonstrate that Kmp is capable of alleviating STZ-induced memory impairment in OVX rats, probably by elevating endogenous hippocampal antioxidants of superoxide dismutase and glutathione, and reducing neuroinflammation. This study suggests that Kmp may be a potential neuroprotective agent against cognitive deficit in AD.

Targeting Renin-Angiotensin System Against Alzheimer's Disease

Renin Angiotensin System (RAS) is a hormonal system that regulates blood pressure and fluid balance through a coordinated action of renal, cardiovascular, and central nervous systems. In addition to its hemodynamic regulatory role, RAS involves in many brain activities, including memory acquisition and consolidation. This review has summarized the involvement of RAS in the pathology of Alzheimer’s disease (AD), and the outcomes of treatment with RAS inhibitors. We have discussed the effect of brain RAS in the amyloid plaque (Aβ) deposition, oxidative stress, neuroinflammation, and vascular pathology which are directly and indirectly associated with AD. Angiotensin II (AngII) via AT1 receptor is reported to increase brain Aβ level via different mechanisms including increasing amyloid precursor protein (APP) mRNA, β-secretase activity, and presenilin expression. Similarly, it was associated with tau phosphorylation, and reactive oxygen species generation. However, these effects are counterbalanced by Ang II mediated AT2 signaling. The protective effect observed with angiotensin receptor blockers (ARBs) and angiotensin converting enzyme inhibitors (ACEIs) could be as the result of inhibition of Ang II signaling. ARBs also offer additional benefit by shifting the effect of Ang II toward AT2 receptor. To conclude, targeting RAS in the brain may benefit patients with AD though it still requires further in depth understanding.

Mitochondrial dysfunction and oxidative stress in aging and cancer

Aging and cancer are the most important issues to research. The population in the world is growing older, and the incidence of cancer increases with age. There is no doubt about the linkage between aging and cancer. However, the molecular mechanisms underlying this association are still unknown. Several lines of evidence suggest that the oxidative stress as a cause and/or consequence of the mitochondrial dysfunction is one of the main drivers of these processes. Increasing ROS levels and products of the oxidative stress, which occur in aging and age-related disorders, were also found in cancer. This review focuses on the similarities between ageing-associated and cancer-associated oxidative stress and mitochondrial dysfunction as their common phenotype.

A Mini-Review of the NADPH oxidases in Vascular Dementia: Correlation with NOXs and Risk Factors for VaD

Oxidative stress (OS) is one of the factors that cause dementia conditions such as Alzheimer’s disease and vascular dementia (VaD). In the pathogenesis of VaD, OS is associated with risk factors that include increased age, hypertension, and stroke. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs) are a molecular source of reactive oxygen species (ROS). According to recent studies, inhibition of NOX activity can reduce cognitive impairment in animal models of VaD. In this article, we review the evidence linking cognitive impairment with NOX-dependent OS, including the vascular NOX and non-vascular NOX systems, in VaD.

Metals and neurodegenerative diseases. A systematic review

Neurodegenerative processes encompass a large variety of diseases with different pathological patterns and clinical presentation such as Amyotrophic Lateral Sclerosis (ALS), Alzheimer Disease (AD) and Parkinson's disease (PD). Genetic mutations have a known causative role, but the majority of cases are likely to be probably caused by a complex gene-environment interaction. Exposure to metals has been hypothesized to increase oxidative stress in brain cells leading to cell death and neurodegeneration. Neurotoxicity of metals has been demonstrated by several in vitro and in vivo experimental studies and it is likely that each metal could be toxic through specific pathways. The possible pathogenic role of different metals has been supported by some epidemiological evidences coming from occupational and ecological studies. In order to assess the possible association between metals and neurodegenerative disorders, several case-control studies have also been carried out evaluating the metals concentration in different biological specimens such as blood/serum/plasma, cerebrospinal fluid (CSF), nail and hair, often reporting conflicting results. This review provides an overview of our current knowledge on the possible association between metals and ALS, AD and PD as main neurodegenerative disorders.

High Serum Levels of Malondialdehyde and 8-OHdG are both Associated with Early Cognitive Impairment in Patients with Acute Ischaemic Stroke

Post-stroke cognitive impairment (PSCI) is an increasingly prevalent sequel after stroke that may associate with poor functional outcome and increased risk of recurrent stroke. We aimed to explore the relationship between oxidative stress biomarkers and the presence of PSCI. 193 first-ever acute ischaemic stroke patients were consecutively enrolled in the current study. The oxidative stress biomarkers malondialdehyde (MDA) and 8-hydroxydeoxyquanosine (8-OHdG) were measured within 24 h after admission. Cognition function was evaluated by the Mini-Mental State Examination (MMSE) at 1 month after stroke. Serum levels of 8-OHdG and MDA were both significantly higher in the PSCI (p < 0.001) compared with the non-PSCI group. Both the serum levels of both 8-OHdG and MDA were negatively correlated with the MMSE score. Receiver operating characteristic curve analysis was used to evaluate 8-OHdG and MDA as markers of a high risk of PSCI and produced area under curve values of 0.700 and 0.793. Adjusted logistic regression showed that serum 8-OHdG and MDA levels remained as independent markers of PSCI. High serum levels of malondialdehyde and 8-OHdG are associated with the presence of PSCI at 1 month after stroke.

Vitamin E family: Role in the pathogenesis and treatment of Alzheimer's disease

Introduction

Vitamin E family, composed by tocopherols and tocotrienols, is a group of compounds with neuroprotective properties. The exact role in the pathogenesis and the benefit of vitamin E as treatment for Alzheimer's disease (AD) are still under debate.

Methods

A literature search in PubMed, Medline, and Cochrane databases has been carried out. All types of studies, from bench and animal models to clinical, were included.

Results

High plasma vitamin E levels are associated with better cognitive performance, even if clear evidence of their ability to prevent or delay cognitive decline in AD is still lacking. Each vitamin E form is functionally unique and shows specific biological functions. Tocotrienols seem to have superior antioxidant and anti-inflammatory properties compared with tocopherols.

Discussion

The benefit of vitamin E as a treatment for AD is still under debate, mainly because of the inconsistent findings from observational studies and the methodological limitations of clinical trials.

Apolipoprotein E ε4 allele and malondialdehyde level are independent risk factors for Alzheimer's disease

Background:

The ε4 allele of Apolipoprotein E is involved in lipid metabolism. Oxidative stress produces an increase in lipid peroxidation that has been implicated in the pathogenic cascade in Alzheimer’s disease. This study estimated the effect of the ε4 allele, malondialdehyde and lipid levels on the risk for Alzheimer’s disease.

Methods:

A total of 41 control subjects and 73 patients with Alzheimer’s disease were recruited. The Apolipoprotein E genotype was determined by amplification of exon 4 of the Apolipoprotein E by polymerase chain reaction (PCR); malondialdehyde concentration was determined by high-pressure liquid chromatography, and serum lipids were measured by routine photometric techniques.

Results:

Malondialdehyde levels were significantly higher in Alzheimer’s disease patients independent of the Apolipoprotein E genotype and ε4 allele. The ε4 allele increases the risk of Alzheimer’s disease by 5.114 times and elevated malondialdehyde levels increase the risk by 9.342.

Conclusion:

The presence of ε4 allele and elevated malondialdehyde levels are independent risk factors for Alzheimer’s disease. These findings support the hypothesis that lipid peroxidation and ε4 allele contribute to the pathogenic cascade in Alzheimer’s disease by different pathways.

The Role of Oxidative Damage in the Pathogenesis and Progression of Alzheimer's Disease and Vascular Dementia

Oxidative stress (OS) has been demonstrated to be involved in the pathogenesis of the two major types of dementia: Alzheimer's disease (AD) and vascular dementia (VaD). Evidence of OS and OS-related damage in AD is largely reported in the literature. Moreover, OS is not only linked to VaD, but also to all its risk factors. Several researches have been conducted in order to investigate whether antioxidant therapy exerts a role in the prevention and treatment of AD and VaD. Another research field is that pertaining to the heat shock proteins (Hsps), that has provided promising findings. However, the role of OS antioxidant defence system and more generally stress responses is very complex. Hence, research on this topic should be improved in order to reach further knowledge and discover new therapeutic strategies to face a disorder with such a high burden which is dementia.

Biomarkers of lipid peroxidation in Alzheimer disease (AD): an update

Increasing evidence suggests that free radical-mediated oxidation of biological substrates is a key feature of Alzheimer's disease (AD) pathogenesis. While it has long been established that biomarkers of lipid peroxidation (LPO) are elevated in AD brain as well as ventricular CSF postmortem, more recent studies have demonstrated increased LPO biomarkers in postmortem brain from subjects with mild cognitive impairment, the earliest clinically detectable phase of dementia and preclinical AD, the earliest detectable pathological phase. Furthermore, multiple LPO biomarkers are elevated in readily accessible biological fluids throughout disease progression. Collectively, these studies demonstrate that LPO is an early feature during disease progression and may be considered a key pathway for targeted therapeutics as well as an enhancer of diagnostic accuracy for early detection of subjects during the prodromal phase.

Changes in phospholipid composition of erythrocyte membrane in Alzheimer's disease

Background

There are several reports indicating a decrease of ethanolamine plasmalogen (pl-PE) in brain tissues and in serum of patients with Alzheimer's disease (AD). The present study aimed to examine the composition of erythrocyte phospholipids including pl-PE in patients with AD.

Method

A high-performance liquid chromatography (HPLC) method that can separate intact plasmalogens and all other phospholipid classes by a single chromatographic run was used.

Results

The ratios of pl-PE, phosphatidylethanolamine (PE) and phosphatidylserine (PS) to sphingomyelin were low as compared to those of the age-matched controls.

Conclusion

These changes in erythrocyte phospholipids may reflect changes induced by oxidative stress, indicating the presence of high oxidative stress in the peripheral blood of AD patients.

Altered serum iron and copper homeostasis predicts cognitive decline in mild cognitive impairment

Alzheimer's disease (AD) brain is marked by severe neuronal death which has been partly attributed to increased oxidative stress. The pathophysiology accounting for this free radical injury is not well-delineated at this point, but one hypothesis is that a derangement in transition metal metabolism contributes to the process. We tested the hypothesis that peripheral derangement of transition metal metabolism is present early in the dementing process. We analyzed non-heme iron and copper levels in serum from subjects with normal cognition, mild cognitive impairment, and early stage senile dementia and followed these subjects over 5 years. An increase in the ratio of serum copper to non-heme iron levels predicted which subjects with mild cognitive impairment would progress to dementia versus those that would remain cognitively stable. This increase did not correlate with changes in expression of iron regulatory protein 2 or selected downstream targets in peripheral lymphocytes. A cDNA-based microarray (IronChip) containing genes relevant to iron and copper metabolism was used to assess transition metal metabolism in circulating lymphocytes from cognitively normal and demented subjects. No gene was identified as being dysregulated more than 2-fold, and verification using quantitative RT-PCR demonstrated no significant changes in expression for ALAS2, FOS, and CTR1. The increased ratio of serum copper to serum iron prior to dementia has potential as a biomarker for cognitive decline and mirrors other changes in serum previously reported by others, but iron and copper metabolism pathways appear to be broadly unaffected in peripheral blood in AD.