Aging is characterized by a gradual decline of the body's biological functions, which can lead to increased production of reactive oxygen species (ROS). Antioxidants neutralize ROS and maintain balance between oxidation and reduction. If ROS production exceeds the ability of antioxidant systems to neutralize, a damaging state of oxidative stress (OS) may exist. The reduced form of glutathione (GSH) is the most abundant antioxidant, and decline of GSH is considered a marker of OS. Our review summarizes the literature on GSH variations with age in healthy adults in brain (in vivo, ex vivo) and blood (plasma, serum), and reliability of in vivo magnetic resonance spectroscopy (MRS) measurement of GSH. A systematic PubMed search identified 35 studies. All in vivo MRS studies (N = 13) reported good to excellent reproducibility of GSH measures. In brain, 3 out of 4 MRS studies reported decreased GSH with age, measured in precuneus, cingulate, and occipital regions, while 1 study reported increased GSH with age in frontal and sensorimotor regions. In post-mortem brain, out of 3 studies, 2 reported decreased GSH with age in hippocampal and frontal regions, while 1 study reported increased GSH with age in a frontal region. Oxidized glutathione disulfide (GSSG) was reported to be increased in caudate with age in 1 study, suggesting OS. Although findings in the brain lacked a clear consensus, the majority of studies suggested a decline of GSH with age. The low number of studies (particularly ex vivo) and potential regional differences may have contributed to variability in the findings in brain. In blood, in contrast, GSH levels predominately were reported to decrease with advancing age (except in the oldest-old, who may represent a select group of particularly successful agers), while GSSG findings lacked consensus. The larger number of studies assessing age-specific GSH level changes in blood (N = 16) allowed for more robust consensus across studies than in brain. Overall, the literature suggests that aging is associated with increased OS in brain and body, but the timing and regional distribution of changes in the brain require further study. The contribution of brain OS to brain aging, and the effect of interventions to raise brain GSH levels on decline of brain function, remain understudied. Given that reliable tools to measure brain GSH exist, we hope this paper will serve as a catalyst to stimulate more work in this field.

INTRODUCTION: Oxidative stress may contribute to brain injury in the Alzheimer's disease (AD) continuum. The antioxidant glutathione (GSH) can be assessed with magnetic resonance spectroscopy (MRS). Because the relationship between GSH and vascular brain injury is unknown in the AD continuum, we address this gap in mild cognitive impairment (MCI). METHODS: 3T Magnetic resonance imaging (MRI)/MRS data were obtained from 31 patients with MCI. GSH and total N ‐acetylaspartate (tNAA; neuroaxonal integrity marker) were measured in posterior cingulate cortex (PCC) and frontal white matter (FWM). Cerebrovascular injury was assessed using white matter hyperintensity (WMH) volume. Global and regional brain tissue integrity were assessed using normalized brain (NBV) and hippocampal volumes. RESULTS: Significant associations were reported in FWM between GSH/total creatine (tCr) and tNAA/tCr, and between GSH and both WMH and NBV. tNAA, GSH/tCr, and tNAA/tCr were higher in PCC than in FWM. DISCUSSION: Our results suggest that oxidative stress contributes to vascular brain injury in MCI. Highlights: Neuronal, vascular, and oxidative injuries occur in the Alzheimer's disease (AD) spectrum. Glutathione (GSH) is the main endogenous antioxidant in the brain. Brain GSH can be measured with magnetic resonance spectroscopy (MRS). We measured brain GSH level in people with mild cognitive impairment (MCI). Low GSH level was associated with vascular brain injury, neuroaxonal damage, and atrophy.

Living with dementia requires decision making about numerous topics including daily activities and advance care planning (ACP). Both individuals living with dementia and care partners require informed support for decision making. We conducted an umbrella review to assess knowledge translation (KT) interventions supporting decision making for individuals living with dementia and their informal care partners. Four databases were searched using 50 different search terms, identifying 22 reviews presenting 32 KT interventions. The most common KT decision topic was ACP ( N = 21) which includes advanced care directives, feeding options, and placement in long‐term care. The majority of KT interventions targeted care partners only ( N = 16), or both care partners and individuals living with dementia ( N = 13), with fewer interventions ( N = 3) targeting individuals living with dementia. Overall, our umbrella review offers insights into the beneficial impacts of KT interventions, such as increased knowledge and confidence, and decreased decisional conflicts. Highlights: Knowledge translation (KT) helps people with dementia and caregivers make decisions. Our umbrella review investigated whether KT interventions helped decision making. KT interventions were beneficial, with advance care planning being the main topic. Thirteen (41%) of the 32 KT interventions were found to be freely accessible online. We recommend the creation of a KT toolkit to guide topic‐specific decision making.

Background: Cerebral small vessel disease (CSVD) is a common neurological condition that contributes to strokes, dementia, disability, and mortality worldwide. We conducted a systematic review and meta-analysis to investigate the use of neuroimaging CSVD markers in machine learning (ML) based diagnosis and prognosis of cognitive impairment and dementia, and identify both methodological changes over time and barriers to clinical translation. Methods: Following the PRISMA guidelines, we systematically searched for original studies that used both neuroimaging CSVD markers and ML methods for diagnosing and prognosing neurodegenerative diseases (preregistration in PROSPERO: CRD42022366767). Each paper was independently reviewed by a pair of reviewers at all stages, with a third consulted to resolve conflicts. We meta-analysed the effectiveness of ML models to distinguish healthy controls from Alzheimer’s dementia and cognitive impairment, using area under the curve (AUC) as the performance metric. Results: We identified 75 studies: 43 on diagnosis, 27 on prognosis, and 5 on both. Nearly 60% of studies were published in the past two years, reflecting a growing interest in using CSVD markers in ML-based diagnosis and prognosis of neurodegenerative diseases, especially Alzheimer’s dementia. This rising interest may be linked to the strong performance of such models: according to our meta-analysis, ML approaches using CSVD markers perform well in differentiating healthy controls from Alzheimer’s dementia (AUC 0.88 [95%-CI 0.85–0.92]) and cognitive impairment (AUC 0.84 [95%-CI 0.74–0.95]). However, the growing interest has not been matched by methodological rigour: only 16 studies met the criteria for inclusion in the meta-analysis due to inconsistent reporting, only five assessed the generalisability of their models on external datasets, and six lacked clear diagnostic criteria. Conclusions: Interest in incorporating CSVD markers into ML models for neurodegenerative disease classification is on the rise, and their performance suggests that this is worth further exploration. Serious methodological issues, including inconsistent reporting, limited generalisability testing, and other potential biases, are unfortunately common and hinder further adoption. Our targeted recommendations provide a roadmap to accelerate the integration of ML into clinical practice.

Cerebrovascular pathology that involves altered protein levels (or signaling) of the transforming growth factor beta (TGFβ) family has been associated with various forms of age-related dementias, including Alzheimer disease (AD) and vascular cognitive impairment and dementia (VCID). Transgenic mice overexpressing TGFβ1 in the brain (TGF mice) recapitulate VCID-associated cerebrovascular pathology and develop cognitive deficits in old age or when submitted to comorbid cardiovascular risk factors for dementia. We characterized the cerebrovascular proteome of TGF mice using mass spectrometry (MS)-based quantitative proteomics. Cerebral arteries were surgically removed from 6-month-old-TGF and wild-type mice, and proteins were extracted and analyzed by gel-free nanoLC-MS/MS. We identified 3602 proteins in brain vessels, with 20 demonstrating significantly altered levels in TGF mice. For total and/or differentially expressed proteins (p ≤ 0.01, ≥ 2-fold change), using multiple databases, we (a) performed protein characterization, (b) demonstrated the presence of their RNA transcripts in both mouse and human cerebrovascular cells, and (c) demonstrated that several of these proteins were present in human extracellular vesicles (EVs) circulating in blood. Finally, using human plasma, we demonstrated the presence of several of these proteins in plasma and plasma EVs. Dysregulated proteins point to perturbed brain vessel vasomotricity, remodeling, and inflammation. Given that blood-isolated EVs are novel, attractive, and a minimally invasive biomarker discovery platform for age-related dementias, several proteins identified in this study can potentially serve as VCID markers in humans.

As adults get older, their body functions decline. This can cause a build up of harmful substances, called reactive oxygen species, which can damage the cells: the process is called oxidative stress. Luckily, the body uses superhero chemicals called antioxidants to fight against oxidative stress, with the most common being a chemical called glutathione. We were curious to know whether glutathione levels change with age, and how. In previous studies, some researchers measured glutathione levels in the brains of healthy individuals and in the preserved brains of people that had passed away. Other researchers measured glutathione levels in the blood. We analyzed all the results to see how they fit together. Compared to young adults, glutathione levels in older people were either higher, lower, or unchanged depending on the brain region scientists looked at. In blood, glutathione levels were usually lower with increasing age. This means that oxidative stress contributes to aging by damaging the cells in different parts of the brain and in the body, and that the superhero chemical provides protection by fighting oxidative stress.