DDAH-1, via regulation of ADMA levels, protects against ischemia-induced blood-brain barrier leakage.

Dimethylarginine dimethylamino hydrolase-1 (DDAH-1) is an important regulator of nitric oxide (NO) metabolism that has been implicated in the pathogenesis of cardiovascular diseases. Nevertheless, its role in cerebral ischemia still needs to be elucidated. Herein, we examined the expression of DDAH-1 in the brain of rat by double-label immunofluorescence staining. DDAH-1 knock-out (DDAH-1-/-) and wild-type rats underwent middle cerebral artery occlusion/reperfusion (MCAO/R). After 24 h, neurological scores, TTC staining and TUNEL assay were used to evaluate neurological damages. 3 and 7-days infarct outcomes were also shown. Blood-brain-barrier (BBB) permeability was examined via Evans blue extravasation and tight junction (TJ) proteins expression and mRNA levels by western blot and RT-qPCR. The levels of plasma asymmetric dimethylarginine (ADMA), NO and ADMA in brain tissue were also assessed. In addition, supplementation of L-arginine to DDAH-1-/- rats was used to explore its role in regulating NO. DDAH-1 was abundantly distributed in cerebral cortex and basal nuclei, and mainly expressed in neurons and endothelial cells. DDAH-1-/- rats showed aggravated neurological damage and BBB disruption, including decrease of TJ proteins expression but indistinguishable mRNA levels after MCAO/R. DDAH-1 depletion and neurological damages were accompanied with increased ADMA levels and decreased NO concentrations. The supplementation with L-arginine partly restored the neurological damages and BBB disruption. To sum up, DDAH-1 revealed to have a protective role in ischemia stroke (IS) and IS-induced leakage of BBB via decreasing ADMA level and possibly via preventing TJ proteins degradation.

Neurotransmitter-stimulated neuron-derived sEVs have opposite effects on amyloid ß-induced neuronal damage.

The ratio of excitatory to inhibitory neurotransmitters is essential for maintaining the firing patterns of neural networks, and is strictly regulated within individual neurons and brain regions. Excitatory to inhibitory (E/I) imbalance has been shown to participate in the progression of neurodegenerative diseases, including Alzheimer's disease (AD). Glutamate excitotoxicity and GABAergic neuron dysfunction appear to be key components of the neuronal cell death that takes place in AD. Since extracellular vesicles (EVs) are now explored as an important vehicle in transmitting signals between cells, we hypothesized that the function of neuron-derived small EVs (sEVs) might be regulated by the status of neurotransmitter balance and that sEVs might affect amyloid ß (Aß) toxicity on neurons. This study aimed to reveal the effects of sEVs from unbalanced neurotransmitter-stimulated neurons on Aß-induced toxicity. We demonstrated the opposite effects of the two groups of sEVs isolated from neurons stimulated by glutamate or GABA on Aß toxicity in vivo and in vitro. The sEVs released from GABA-treated neurons alleviated Aß-induced damage, while those released from glutamate-treated neurons aggravated Aß toxicity. Furthermore, we compared the microRNA (miRNA) composition of sEVs isolated from glutamate/GABA/PBS-treated neurons. Our results showed that glutamate and GABA oppositely regulated miR-132 levels in sEVs, resulting in the opposite destiny of recipient cells challenged with Aß. Our results indicated that manipulating the function of sEVs by different neurotransmitters may reveal the mechanisms underlying the pathogenesis of AD and provide a promising strategy for AD treatment.

Resveratrol Abrogates Hypoxia-Induced Up-Regulation of Exosomal Amyloid-ß Partially by Inhibiting CD147.

Hypoxia promotes both total extracellular and exosomal amyloid-ß (Aß) production and aggravates Alzheimer's disease (AD). Resveratrol (RSV) has been proved to be neuroprotective in AD models, and down-regulated the expression of CD147, an additional subunit of γ-secretase. In this study, we aimed to explore the role and mechanisms of RSV in hypoxia-induced upregulation of Aß, especially exosomal Aß. SH-SY5Y cells and HEK293 cells overexpressing amyloid precursor protein (APP) as well as C57BL/6 mice were treated with RSV and exposed to hypoxic conditions. The expression of SIRT1 or CD147 was modulated by transfection of specific siRNAs or plasmid. Aß1-40 and Aß1-42 levels were determined by ELISA. Hypoxia increased the levels of both Aß1-40 and Aß1-42 in the hippocampal lysates and serum-derived exosomes of mice. Hypoxia also increased both Aß1-40 and Aß1-42 levels in the total culture medium (CM), cell-derived exosomal lysates, and exosome-free CM of both cell lines. Treatment with RSV abrogated these changes in Aß expression, inhibited the hypoxia-induced down-regulation of SIRT1 and up-regulation of CD147. Knockdown of SIRT1 promote total Aß level but has no effect on exosomal Aßs expression. Knockdown of CD147 inhibits both total and exosomal Aßs expression. Furthermore, overexpressing CD147 in cells exposed to hypoxia facilitated the production of Aß1-40 and Aß1-42, while application of RSV reduced the CD147 expression as well as Aß levels in both exosomes and exosome-free CM. These results suggested that RSV abrogated hypoxia-induced up-regulation of total and exosomal Aß partially by inhibiting CD147.

Serum Calcium is Related to the Degree of Artery Stenosis in Acute Ischemic Stroke.

BACKGROUND/AIMS: Acute ischemic stroke is caused by stenosis of artery supplying to brain. We aimed to detect some metabolites in the serum that would be related to the degree of artery stenosis and to analyze potential mechanisms. METHODS: Patients diagnosed with acute ischemic stroke were divided into two groups according to their degree of artery stenosis (which was determined by computed tomographic angiography): a mild group (stenosis ≤ 30%) and a severe group (stenosis > 30%). Serum from these patients was collected, and we focused on the differences in the concentrations of calcium, uric acid, low density lipoprotein and homocysteine. The dataset GSE11583 from the Gene Expression Omnibus database was analyzed to find the potential mechanism using bioinformatics methods. RESULTS: Among the four metabolites, the only difference that reached significance between the two groups was in the concentration of calcium in serum (2.27±0.08 mmol/L vs 2.21±0.08 mmol/L). By comparing the gene expression levels between normal endothelial cells and adaptive remodeling endothelial cells in GSE11583, we identified 51 upregulated and 40 downregulated genes in adaptive remodeling endothelial cells. The gene set enrichment analysis revealed that upregulated genes were enriched in a phosphatidylinositol signaling system, which is closely involved in the calcium signaling pathway. CONCLUSION: Our results suggest that the concentration of serum calcium is higher in patients with more severe artery stenosis lesions and that the phosphatidylinositol signaling system is a key biological pathway involved in this process.

Homocysteine is Associated with Exaggerated Morning Blood Pressure Surge in Patients with Acute Ischemic Stroke.

BACKGROUND: Considerable researches suggest that high level of homocysteine (Hcy) is associated with the risk of ischemic stroke. Ambulatory blood pressure monitoring (ABPM) parameters have also been confirmed associated with cardio-cerebrovascular events. However, the relationship between Hcy and ABPM parameters remains unclear in patients with acute ischemic stroke. In this study, we aim to investigate the association between Hcy level and ABPM parameters in patients with acute ischemic stroke. METHODS: We enrolled 60 patients with acute ischemic stroke who received ABPM. We calculated ABPM parameters like morning blood pressure surge (MBPS), ambulatory arterial stiffness index, blood pressure variability, and night dipping patterns. RESULTS: Multivariate logistic regression analysis indicated that patients in the top quartile of Hcy level tended to have a higher level of prewaking and sleep-trough MBPS compared with patients in the lower 3 quartiles after adjusted for age and gender (P = .028 and P = .030, respectively). When treating Hcy as a continuous variable, the linear regression showed the association between Hcy level and both MBPS parameters remained significant (prewaking MBPS, r = .356, P = .022; sleep-trough MBPS, r = .365, P = .017, respectively). However, there is no association between Hcy level and ambulatory arterial stiffness index, blood pressure variability or night dipping patterns (P = .635, P = .348 and P = .127 respectively). CONCLUSIONS: There is a relationship between the 2 major cerebrovascular risk factors: MBPS and Hcy.

Prognostic value of morning blood pressure surge in clinical events: a meta-analysis of longitudinal studies.

BACKGROUND: Cardiovascular (CV) events tend to occur more often in the morning. Thus, morning blood pressure surge (MS) may be related to the risk of CV events. The results of several studies evaluating the prognostic value of MS are inconsistent. In this study, we conducted a systematic review and meta-analysis to summarize the significance of MS in predicting future CV events. METHODS: Among the related literature, we discovered 7 eligible longitudinal studies that had evaluated MS and had followed 14,133 patients with a mean follow-up period of 7.1 years. We evaluated the predictive value of MS for future CV events, stroke, and all-cause mortality in this meta-analysis. RESULTS: For subjects with higher pre-waking MS than those with lower pre-waking MS, the pooled relative risk (RR) of all-cause mortality, stroke, and total CV events were 1.20 (95% confidence interval [CI]: .85-1.70, P = .290; 4 studies), 1.20 (95% CI: .94-1.53, P = .146; 3 studies), and 1.24 (95% CI: .60-2.53, P = .562; 3 studies), respectively. For subjects with higher sleep-trough MS, the pooled RR of all-cause mortality was 1.29 (95% CI: 1.11-1.52, P = .001; 4 studies). No significant publication bias was observed. CONCLUSIONS: Excess sleep-trough MS is a strong predictor for future all-cause mortality. Individuals with higher pre-waking MS showed a tendency for increased risk of CV outcomes, but the differences were insignificant.

Nomogram for predicting moderate-to-severe sleep-disordered breathing in patients with acute ischaemic stroke: a retrospective cohort study.

OBJECTIVES: Moderate-to-severe sleep-disordered breathing (SDB) is prevalent in patients with acute ischaemic stroke (AIS) and is associated with an increased risk of unfavourable prognosis. We aimed to develop and validate a reliable scoring system for the early screening of moderate-to-severe SDB in patients with AIS, with the objective of improving the management of those patients at risk. STUDY DESIGN: We developed and validated a nomogram model based on univariate and multivariate logistic analyses to identify moderate-to-severe SDB in AIS patients. Moderate-to-severe SDB was defined as an apnoea-hypopnoea index (AHI) ≥15. To evaluate the effectiveness of our nomogram, we conducted a comparison with the STOP-Bang questionnaire by analysing the area under the receiver operating characteristic curve. SETTING: Large stroke centre in northern Shanghai serving over 4000 inpatients, 100 000 outpatients and emergency visits annually. PARTICIPANTS: We consecutively enrolled 116 patients with AIS from the Shanghai Tenth People's Hospital. RESULTS: Five variables were independently associated with moderate-to-severe SDB in AIS patients: National Institutes of Health Stroke Scale score (OR=1.20; 95% CI 0.98 to 1.47), neck circumference (OR=1.50; 95% CI 1.16 to 1.95), presence of wake-up stroke (OR=21.91; 95% CI 3.08 to 156.05), neuron-specific enolase level (OR=1.27; 95% CI 1.05 to 1.53) and presence of brainstem infarction (OR=4.21; 95% CI 1.23 to 14.40). We developed a nomogram model comprising these five variables. The C-index was 0.872, indicated an optimal agreement between the observed and predicted SDB patients. CONCLUSIONS: Our nomogram offers a practical approach for early detection of moderate-to-severe SDB in AIS patients. This tool enables individualised assessment and management, potentially leading to favourable outcomes.

Adiponectin Levels Are Associated with White Matter Lesions (WMLs) and Cognitive Impairment.

METHOD: In the present study, 126 patients, 90 cases in the WML group and 36 cases in the control group, were analyzed to explore the relationship between adiponectin and WMLs. All patients underwent an MRI scan to assess whether white matter lesions happened. And the serum levels of adiponectin were detected by ELISA. RESULTS: In this study, according to Fazekas criteria, WMLs were divided into different severity groups. With the increase of WML score, the level of adiponectin decreased, and linear correlation analysis shows that adiponectin is negatively correlated with the severity of white matter lesions (p < 0.001). And adiponectin level was significantly positively correlated with MoCA score (p < 0.05). Moreover, adiponectin in the WMLs combined with the cognitive impairment group was significantly reduced (p < 0.01). CONCLUSION: The level of adiponectin is independently associated with WMLs and cognitive function, which suggests that adiponectin may be a protective factor for WMLs and cognitive function.

Associations of Abdominal Visceral Fat Content and Plasma Adiponectin Level With Intracranial Atherosclerotic Stenosis: A Cross-Sectional Study.

Background: Abdominal obesity and adipocytokines are closely related to atherosclerosis, and adiponectin level is considered one of the important clinical indicators. This study aimed to analyze the associations of abdominal visceral fat content and adiponectin level with intracranial atherosclerotic stenosis (ICAS). Methods: A total of 186 patients were enrolled in this study. Patients were distributed into ICAS and non-ICAS by the degree of artery stenosis. Plasma adiponectin levels and the ratio of visceral adipose tissue (VAT) to subcutaneous adipose tissue (SAT) were measured. The related factors of intracranial atherosclerotic stenosis were determined using multivariable logistic regression analysis. Results: The VAT/SAT ratio (OR, 26.08; 95% CI, 5.92-114.83; p < 0.001) and adiponectin (OR, 0.61; 95% CI, 0.44-0.84; p = 0.002) were found to be the independent predictors of ICAS in a multivariable logistic regression analysis. The prevalence of ICAS increased (T1: 27.4%; T2: 50.0%; T3: 75.8%) as the VAT/SAT ratio tertile increased (p < 0.001). The prevalence of ICAS decreased (T1: 72.6%; T2: 54.8%; T3: 25.8%) as the adiponectin tertile increased (p < 0.001). In ROC curves analysis, VAT/SAT ratio had a sensible accuracy for the prediction of ICAS. The optimal cut-off value of VAT/SAT ratio to predict ICAS in this study was 1.04 (AUC: 0.747; p < 0.001; sensitivity: 67.4%; specificity: 74.7%). The optimal adiponectin cutoff was 3.03 ug/ml (AUC: 0.716; p < 0.001; sensitivity:75.8%; specificity: 61.5%). Conclusion: Higher VAT/SAT ratio and lower plasma adiponectin levels were closely related to the increased risk of intracranial atherosclerotic stenosis.

Effect of marital status on survival in glioblastoma multiforme by demographics, education, economic factors, and insurance status.

The relationship between marital status and glioblastoma multiforme (GBM) has not been addressed in depth. Here, we aimed to investigate the association between marital status and survival in GBM. We searched the Surveillance, Epidemiology, and End Results (SEER) database and extracted the data of eligible patients diagnosed with GBM after 2004. Marital status was classified as married, divorced/separated, widowed, and single. A Kaplan-Meier test was conducted to compare the survival curves of different groups. Multivariate Cox regression was performed to evaluate overall survival (OS) and cause-specific survival (CSS) in different groups. Subgroup analysis was applied according to demographics, typical education and income levels in the locale, and insurance status. A total of 30 767 eligible patients were included. The median OS values were 9, 7, 3, 9 months in married, divorced/separated, widowed, and single patients, respectively. After adjustment for other covariates, married patients had better OS and CSS than other patients had. In addition to marital status, demographic factors, disease progression factors, local educational level, and insurance status were also associated with survival in GBM. Furthermore, subgroup analyses revealed the protective effect of marriage in most of the comparisons. Notably, the protective effect of marriage becomes more and more apparent as time goes on. The advantageous effect of marriage on GBM survival is especially prominent in patients who are male, older than 60 years of age, White, or living in middle-income counties. In conclusion, marital status is an independent prognostic factor for GBM.

Marital status is associated with survival of patients with astrocytoma.

The prognostic role of marital status in patients with astrocytoma has not been fully explored. In this study we investigated the association of marital status and survival of astrocytoma. We extracted the eligible patients with astrocytoma diagnosed after 2000 from the Surveillance, Epidemiology, and End Results (SEER) database. The marital status was classified into married, divorced/separated, widowed, and single. The differences in OS and CSS were compared using the Kaplan-Meier log-rank test, and multivariate Cox regression was applied to analyze the risk factors for OS and CSS. Subgroup analyses were conducted to explore the association of marital status with patients in different sex, age, race, histologic type based on 2016 WHO grade, year of diagnosis, median household income and surgery status. A total of 43, 324 eligible patients were included. The median overall survival is 17, 11, 9, 3 months in single, married, divorced/separated patients, and widowed patients, respectively. Although single patients seemed to have the longest overall survival, after adjusted for other co-variables, married patients had the best OS and CSS compared with others, while divorced/separated or widowed patients had the worst CSS in different subgroups. Furthermore, subgroup analyses revealed some interesting results such as the CSS showed no difference between single and married for women (P = 0.122). In conclusion, marital status was an independent prognostic factor for astrocytoma patients. The healthcare system should aware of that patients with an aborted marriage need more social and physiological support.

Hypoxia increases amyloid-ß level in exosomes by enhancing the interaction between CD147 and Hook1.

Hypoxia promotes the accumulation of amyloid-ß (Aß), which is related to the pathogenesis of Alzheimer's disease (AD). CD147 is considered as an additional subunit of γ-secretase regulated by hypoxia, and has been identified in exosomes. Aß is also found in exosomes that participate in the intercellular communication and amyloids propagation. This study was to investigate the role of CD147 in hypoxia-induced accumulation of Aß in exosomes. Our results showed that hypoxia increased the levels of Aß40 and Aß42 in exosomes and enhanced the interaction between CD147 and Hook1 in SH-SY5YAPP695 cells. Moreover, hypoxia increased the interaction between amyloid precursor protein (APP) and CD147 as well as the expression of CD147 in isolated membrane. After we interfered the interaction between CD147 and Hook1 by decreasing Rab22a expression, the hypoxia induced Aß accumulation in exosomes was significantly suppressed. In addition, the increased interaction between CD147 and Hook1 was further confirmed in hypoxia exposed C57BL/6 mice. Our findings reveal that hypoxia may increase exosome Aß level by enhancing the interaction between CD147 and Hook1.

ß-amyloid increases neurocan expression through regulating Sox9 in astrocytes: A potential relationship between Sox9 and chondroitin sulfate proteoglycans in Alzheimer's disease.

OBJECTIVE: This study aimed to investigate whether ß-amyloid (Aß) was able to enhance neurocan expression in a Sox9 dependent manner in astrocytes. METHODS AND MATERIALS: Astrocytes were incubated with Aß at different concentrations, the expression of Sox9 and neurocan was detected by Western blot assay. Meanwhile, the viability and proliferation of astrocytes were assessed by MTT assay. Then, the Sox9 expression was silenced, and the expression of Sox9 and neurocan was examined. RESULTS: After incubation with Aß, the viability of astrocytes was increased regardless silencing of Sox9 (all P<0.05). The proliferation of astrocytes was also gradually increased with the increase in the time of Aß incubation (all P<0.05). With the increase in Aß concentration, the expression of Sox9 and neurocan was also increased (all P<0.05). However, after silencing of Sox9 expression, the neurocan expression was significantly reduced as compared to control group and scra-siRNA group (all P<0.05). CONCLUSION: Our study shows the viability and proliferation of astrocytes are significantly increased by Aß in a dose dependent manner. Moreover, Aß may effectively up-regulate the neurocan expression via regulating Sox9.