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A Post-hoc Study of D-Amino Acid Oxidase in Blood as an Indicator of Post-stroke Dementia.

ABSTRACT: Stroke is an important risk factor for dementia. Epidemiological studies have indicated a high incidence of dementia in stroke patients. There is currently no effective biomarker for the diagnosis of post-stroke dementia (PSD). D-amino acid oxidase (DAO) is a flavin-dependent enzyme widely distributed in the central nervous system. DAO oxidizes D-amino acids, a process which generates neurotoxic hydrogen peroxide and leads to neurodegeneration. This study aimed to examine post-stroke plasma DAO levels as a biomarker for PSD. In total, 53 patients with PSD, 20 post-stroke patients without dementia (PSNoD), and 71 age- and gender-matched normal controls were recruited. Cognitive function was evaluated at more than 30 days post-stroke. Plasma DAO was measured using the enzyme-linked immunosorbent assay. White matter hyperintensity (WMH), a neuroimaging biomarker of cerebral small vessel diseases, was determined by magnetic resonance imaging. We found that plasma DAO levels were independently higher in PSD subjects than in PSNoD subjects or the controls and were correlated with the WMH load in stroke patients. Using an area under the curve (AUC)/receiver operating characteristic analysis, plasma DAO levels were significantly reliable for the diagnosis of PSD. The sensitivity and specificity of the optimal cut-off value of 321 ng/ml of plasma DAO for the diagnosis of PSD were 75 and 88.7%, respectively. In conclusion, our data support that plasma DAO levels were increased in PSD patients and correlated with brain WMH, independent of age, gender, hypertension, and renal function. Plasma DAO levels may therefore aid in PSD diagnosis.

SUBMITTER: Chen YC

PROVIDER: S-EPMC6497996 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Association of major blood lipids with post-stroke dementia: A community-based cohort study.

Project description:Background and purposeThe roles of blood low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides in the development of post-stroke dementia remain uncertain. This study was to investigate their potential associations.MethodsA retrospective cohort study was conducted using the Clinical Practice Research Datalink. Patients with first-ever stroke but no prior dementia were followed up for 10 years. Cox regression was used to examine the association of baseline LDL-C, HDL-C and triglycerides with post-stroke dementia.ResultsAmongst 63,959 stroke patients, 15,879 had complete baseline data and were included in our main analysis. 10.8% developed dementia during a median of 4.6 years of follow-up. The adjusted hazard ratio of dementia for LDL-C (per log mmol/l increase) was 1.29 (95% confidence interval [CI] 1.14-1.47), with a linear increasing trend (p trend <0.001). The counterpart for triglycerides was 0.79 (95% CI 0.69-0.89), with a linear decreasing trend (p trend <0.001). For HDL-C, there was no association with dementia (adjusted hazard ratio 0.89, 95% CI 0.74-1.08) or a linear trend (p trend = 0.22).ConclusionsBlood lipids may affect the risk of post-stroke dementia in different ways, with higher risk associated with LDL-C, lower risk associated with triglycerides, and no association with HDL-C.

| S-EPMC9303428 | biostudies-literature

Blood levels of D-amino acid oxidase vs. D-amino acids in reflecting cognitive aging.

Project description:Feasible peripheral biomarker for Alzheimer's disease (AD) is lacking. Dysregulation of N-methyl-D-aspartate (NMDA) receptor is implicated in the pathogenesis of AD. D-amino acid oxidase (DAO) and amino acids can regulate the NMDA receptor function. This study aimed to examine whether peripheral DAO and amino acids levels are characteristic of age-related cognitive decline. We enrolled 397 individuals (including amnestic mild cognitive impairment (MCI), mild AD, moderate to severe AD, and healthy elderly). DAO levels in the serum were measured using ELISA. Amino acids levels in serum were measured by high performance liquid chromatography. Severity of the cognitive deficits in subjects was assessed using Clinical Dementia Rating Scale (CDR). The DAO levels increased with the severity of the cognitive deficits. DAO levels were significantly associated with D-glutamate and D-serine levels. The Receiver Operating Characteristics analysis of DAO levels for AD patients vs. healthy controls determined the optimal cutoff value, 30.10, with high sensitivity (0.842) and specificity (0.889) (area under curve = 0.928). This is the first study indicating that the peripheral DAO levels may increase with age-related cognitive decline. The finding supports the hypofunction of NMDA receptor hypothesis in AD. Whether DAO could serve as a potential surrogate biomarker needs further studies.

| S-EPMC5665939 | biostudies-literature

Blood pressure variability and outcome in acute ischemic and hemorrhagic stroke: a post hoc analysis of the HeadPoST study.

Project description:The Head Positioning in Acute Stroke Trial (HeadPoST) is a pragmatic, international, cluster crossover randomized trial of 11,093 patients with acute stroke assigned to a lying-flat (0°) or sitting-up (head elevated ≥30°) position. This post hoc analysis aimed to determine the association between blood pressure variability (BPV) and outcomes for patients from a wide range of international clinical settings and how the association was modified by randomized head position. BPV was defined according to the standard criteria, with the key parameter considered the coefficient of variation (CV) of systolic BP (SBP) over 24 h. Outcome was ordinal 90-day Modified Rankin Scale (mRS) score. The association was analyzed by ordinal, logistic regression, hierarchical, mixed models with fixed intervention (lying flat vs. sitting up), and fixed period, random cluster, and random cluster-period, effects. Nine thousand one hundred and fifty six (8324 acute ischemic stroke and 817 intracerebral hemorrhage; mean age 68.1 years; 39.2% women) were included in the analysis. CV of SBP had a significant linear association with unfavorable shift of mRS at 90 days (adjusted odds ratio 1.06, 95% confidence interval 1.02-1.11; P = 0.01). There was no heterogeneity of the association by randomized head positioning. In addition, CV of diastolic BP (DBP) (1.08, 1.03-1.12; P = 0.001) over 24 h post stroke was significantly associated with 3-month poor outcome. The association was more apparent in sitting-up position (1.12, 1.06-1.19) compared with lying-flat position (1.03, 0.98-1.09) (P interaction = 0.005). BPV was associated with adverse stroke outcome, and the magnitude of the association was greater with sitting-up head positioning in terms of DBP variability.

| S-EPMC6544517 | biostudies-literature

Yin and Yang in Post-Translational Modifications of Human D-Amino Acid Oxidase.

Project description:In the central nervous system, the flavoprotein D-amino acid oxidase is responsible for catabolizing D-serine, the main endogenous coagonist of N-methyl-D-aspartate receptor. Dysregulation of D-serine brain levels in humans has been associated with neurodegenerative and psychiatric disorders. This D-amino acid is synthesized by the enzyme serine racemase, starting from the corresponding L-enantiomer, and degraded by both serine racemase (via an elimination reaction) and the flavoenzyme D-amino acid oxidase. To shed light on the role of human D-amino acid oxidase (hDAAO) in D-serine metabolism, the structural/functional relationships of this enzyme have been investigated in depth and several strategies aimed at controlling the enzymatic activity have been identified. Here, we focused on the effect of post-translational modifications: by using a combination of structural analyses, biochemical methods, and cellular studies, we investigated whether hDAAO is subjected to nitrosylation, sulfhydration, and phosphorylation. hDAAO is S-nitrosylated and this negatively affects its activity. In contrast, the hydrogen sulfide donor NaHS seems to alter the enzyme conformation, stabilizing a species with higher affinity for the flavin adenine dinucleotide cofactor and thus positively affecting enzymatic activity. Moreover, hDAAO is phosphorylated in cerebellum; however, the protein kinase involved is still unknown. Taken together, these findings indicate that D-serine levels can be also modulated by post-translational modifications of hDAAO as also known for the D-serine synthetic enzyme serine racemase.

| S-EPMC8141710 | biostudies-literature

Expression of D-Amino Acid Oxidase (DAO/DAAO) and D-Amino Acid Oxidase Activator (DAOA/G72) during Development and Aging in the Human Post-mortem Brain.

Project description:In the brain, D-amino acid oxidase (DAO/DAAO) mainly oxidizes D-serine, a co-agonist of the N-methyl-D-aspartate (NMDA) receptors. Thus, DAO can regulate the function of NMDA receptors via D-serine breakdown. Furthermore, DAO activator (DAOA)/G72 has been reported as both DAOA and repressor. The co-expression of DAO and DAOA genes and proteins in the human brain is not yet elucidated. The aim of this study was to understand the regional and age span distribution of DAO and DAOA (mRNA and protein) in a concomitant manner. We determined DAO and DAOA mRNA and protein expression across six brain regions in normal human post-mortem brain samples (16 weeks of gestation to 91 years) using quantitative real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. We found higher expression of DAO mRNA in the cerebellum, whereas lower expression of DAO protein in the cerebellum compared to the other brain regions studied, which suggests post-transcriptional regulation. We detected DAOA protein but not DAOA mRNA in all brain regions studied, suggesting a tightly regulated expression. To understand this regulation at the transcriptional level, we analyzed DNA methylation levels at DAO and DAOA CpG sites in the cerebellum and frontal cortex of control human post-mortem brain obtained from Gene Expression Omnibus datasets. Indeed, DAO and DAOA CpG sites in the cerebellum were significantly more methylated than those in the frontal cortex. While investigating lifespan effects, we found that DAO mRNA levels were positively correlated with age <2 years in the cerebellum and amygdala. We also detected a significant positive correlation (controlled for age) between DAO and DAOA protein in all of the brain regions studied except for the frontal cortex. In summary, DAO and DAOA expression in the human brain are both age and brain region dependent.

| S-EPMC5382383 | biostudies-literature

Blood pressure variability and outcome in acute severe stroke: A post hoc analysis of CHASE-A randomized controlled trial.

Project description:The influence of blood pressure variability (BPV) on outcomes in patients with severe stroke is still largely unsettled. Using the data of CHASE trial, the authors calculated the BPV during the acute phase and subacute phase of severe stroke, respectively. The primary outcome was to investigate the relationship between BPV and 90-day modified Rankin scale (mRS) ≥ 3. The BPV was assessed by eight measurements including standard deviation (SD), mean, maximum, minimum, coefficient of variation (CV), successive variation (SV), functional successive variation (FSV), and average real variability (ARV). Then, the SD of SBP was divided into quintiles and compared the quintile using logistic regression in three models. The acute phase included 442 patients, and the subacute phase included 390 patients. After adjustment, six measurements of BPV during the subacute phase rather than acute phase were strongly correlated with outcomes including minimum (odds ratio [OR]: 0.83, 95% confidence interval [CI]: 0.69-0.99, p = .037), SD (OR: 1.10, 95% CI: 1.03-1.17, p = .007), CV (OR: 1.12, 95% CI: 1.03-1.23, p = .012), ARV (OR: 1.13, 95% CI: 1.05-1.20, p < .001), SV (OR: 1.09, 95% CI: 1.04-1.15, p = .001), and FSV (OR: 1.12, 95% CI: 1.05-1.19, p = .001). In the logistic regression, the highest fifth of SD of SBP predicted poor outcome in all three models. In conclusion, the increased BPV was strongly correlated with poor outcomes in the subacute phase of severe stroke, and the magnitude of association was progressively increased when the SD of BP was above 12.

| S-EPMC8029725 | biostudies-literature

Increased D-amino acid oxidase expression in the bilateral hippocampal CA4 of schizophrenic patients: a post-mortem study.

Project description:An important risk gene in schizophrenia is D-: amino acid oxidase (DAAO). To establish if expression of DAAO is altered in cortical, hippocampal or thalamic regions of schizophrenia patients, we measured gene expression of DAAO in a post-mortem study of elderly patients with schizophrenia and non-affected controls in both hemispheres differentiating between gray and white matter. We compared cerebral post-mortem samples (granular frontal cortex BA9, middle frontal cortex BA46, superior temporal cortex BA22, entorhinal cortex BA28, sensoric cortex BA1-3, hippocampus (CA4), mediodorsal nucleus of the thalamus) from 10 schizophrenia patients to 13 normal subjects investigating gene expression of DAAO in the gray and white matter of both hemispheres of the above-mentioned brain regions by in situ-hybridization. We found increased expression of DAAO-mRNA in the hippocampal CA4 of schizophrenic patients. Compared to the control group, both hemispheres of the hippocampus of schizophrenic patients showed an increased expression of 46% (right, P = 0.013) and 54% (left, P = 0.019), respectively. None of the other regions examined showed statistically significant differences in DAAO expression. This post-mortem study demonstrated increased gene expression of DAAO in the left and right hippocampus of schizophrenia patients. This increased expression could be responsible for a decrease in local D-: serine levels leading to a NMDA-receptor hypofunction that is hypothesized to play a major role in the pathophysiology of schizophrenia. However, our study group was small and results should be verified using larger samples.

| S-EPMC2776935 | biostudies-other

Mechanistic Studies of an Amine Oxidase Derived from d-Amino Acid Oxidase.

Project description:The flavoprotein d-amino acid oxidase has long served as a paradigm for understanding the mechanism of oxidation of amino acids by flavoproteins. Recently, a mutant d-amino acid oxidase (Y228L/R283G) that catalyzed the oxidation of amines rather than amino acids was described [Yasukawa, K., et al. (2014) Angew. Chem., Int. Ed. 53, 4428-4431]. We describe here the use of pH and kinetic isotope effects with (R)-?-methylbenzylamine as a substrate to determine whether the mutant enzyme utilizes the same catalytic mechanism as the wild-type enzyme. The effects of pH on the steady-state and rapid-reaction kinetics establish that the neutral amine is the substrate, while an active-site residue, likely Tyr224, must be uncharged for productive binding. There is no solvent isotope effect on the kcat/Km value for the amine, consistent with the neutral amine being the substrate. The deuterium isotope effect on the kcat/Km value is pH-independent, with an average value of 5.3, similar to values found with amino acids as substrates for the wild-type enzyme and establishing that there is no commitment to catalysis with this substrate. The kcat/KO2 value is similar to that seen with amino acids as the substrate, consistent with the oxidative half-reaction being unperturbed by the mutation and with flavin oxidation preceding product release. All of the data are consistent with the mutant enzyme utilizing the same mechanism as the wild-type enzyme, transfer of hydride from the neutral amine to the flavin.

| S-EPMC5472355 | biostudies-literature

Blood pressure during long-term cilostazol-based dual antiplatelet therapy after stroke: a post hoc analysis of the CSPS.com trial.

Project description:We determined the associations of follow-up blood pressure (BP) after stroke as a time-dependent covariate with the risk of subsequent ischemic stroke, as well as those of BP levels with the difference in the impact of long-term clopidogrel or aspirin monotherapy versus additional cilostazol medication on secondary stroke prevention. In a sub-analysis of a randomized controlled trial (CSPS.com), patients between 8 and 180 days after stroke onset were randomly assigned to receive aspirin or clopidogrel alone, or a combination of cilostazol with aspirin or clopidogrel. The percent changes, differences, and raw values of follow-up BP were examined. The primary efficacy outcome was the first recurrence of ischemic stroke. In a total of 1657 patients (69.5 ± 9.3 years, female 29.1%) with median 1.5-year follow-up, ischemic stroke recurred in 74 patients. The adjusted hazard ratio for ischemic stroke of a 10% systolic BP (SBP) increase from baseline was 1.19 (95% CI 1.03-1.36), that of a 10 mmHg SBP increase was 1.14 (1.03-1.28), and that of SBP as the raw value with the baseline SBP as a fixed (time-independent) covariate was 1.14 (1.00-1.31). Such significant associations were not observed in diastolic BP-derived variables. The estimated adjusted hazard ratio curves for the outcome showed the benefit of dual therapy over a wide SBP range between ≈120 and ≈165 mmHg uniformly. Lower long-term SBP levels after ischemic stroke were associated with a lower risk of subsequent ischemic events. The efficacy of dual antiplatelet therapy including cilostazol for secondary stroke prevention was evident over a wide SBP range.

| S-EPMC11374707 | biostudies-literature

Sustained efficacy of incobotulinumtoxina repeated injections for upper-limb post-stroke spasticity: A post hoc analysis.

Project description:ObjectiveThis post hoc analysis assessed the impact of repeated incobotulinumtoxinA injections on muscle tone, disability, and caregiver burden in adults with upper-limb post-stroke spasticity.DesignData from the double-blind, placebo-controlled main period and three open-label extension cycles of two Phase 3, randomized, multicentre trials were pooled.MethodsSubjects received incobotulinumtoxinA 400 Units at 12-week intervals (±3 days) (study 3001, NCT01392300) or ≤ 400 Units at ≥12-week intervals based on clinical need (study 0410, NCT00432666). Ashworth Scale (AS) arm sumscore (sum of elbow, wrist, finger and thumb flexor, and forearm pronator AS scores), Disability Assessment Scale (DAS), and Carer Burden Scale (CBS) scores were assessed.ResultsAmong 465 subjects, from study baseline to 4 weeks post-injection, mean (standard deviation) AS arm sumscore improved continuously: main period, -3.23 (2.55) (placebo, -1.49 (2.09)); extension cycles 1, 2, and 3, -4.38 (2.85), -4.87 (3.05), and -5.03 (3.02), respectively. DAS principal target domain responder rate increased from 47.4% in the main period (placebo 27.2%) to 66.6% in extension cycle 3. Significant improvements in CBS scores 4 weeks post-injection accompanied improved functional disability in all cycles.ConclusionIncobotulinumtoxinA conferred sustained improvements in muscle tone, disability, and caregiver burden in subjects with upper-limb post-stroke spasticity.

| S-EPMC8772361 | biostudies-literature

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