Current Neurovascular Research - Volume 16, Issue 4, 2019

Background: In the developing cerebral cortex, Radial Glia (RG) multipotent neural stem cell, among other functions, differentiate into astrocytes and serve as a scaffold for blood vessel development. After some time, blood vessel Endothelial Cells (ECs) become associated with astrocytes to form the neurovascular Blood-Brain Barrier (BBB) unit. Objective: Since little is known about the mechanisms underlying bidirectional RG-ECs interactions in both vascular development and astrocyte differentiation, this study investigated the impact of interactions between RG and ECs mediated by secreted factors on EC maturation and gliogenesis control. Methods: First, we demonstrated that immature vasculature in the murine embryonic cerebral cortex physically interacts with Nestin positive RG neural stem cells in vivo. Isolated Microcapillary Brain Endothelial Cells (MBEC) treated with the conditioned medium from RG cultures (RG-CM) displayed decreased proliferation, reduction in the protein levels of the endothelial tip cell marker Delta-like 4 (Dll4), and decreased expression levels of the vascular permeability associated gene, plasmalemma vesicle-associated protein-1 (PLVAP1). These events were also accompanied by increased levels of the tight junction protein expression, zonula occludens-1 (ZO-1). Results: Finally, we demonstrated that isolated RG cells cultures treated with MBEC conditioned medium promoted the differentiation of astrocytes in a Vascular Endothelial Growth Factor-A (VEGF-A) dependent manner. Conclusion: These results suggest that the bidirectional interaction between RG and ECs is essential to induce vascular maturation and astrocyte generation, which may be an essential cell-cell communication mechanism to promote BBB establishment.

Background: Less is known about the prognostic value of serum cystatin C in acute ischemic stroke (AIS) patients treated with intravenous thrombolysis (IVT). The aim of the present study was to examine the association between serum cystatin C levels and prognosis of AIS patients after IVT. Methods: Serum cystatin C was measured within 24 hours after recombinant tissue plasminogen activator (rt-PA) treatment in 280 consecutively recruited patients with AIS. The main outcomes included combination of death and major disability, death, major disability (modified Rankin Scale score 3-5) and vascular events at 3-month follow-up. Results: During the 3-month follow-up, 94 patients (33.6%) experienced death or major disability (28 deaths and 66 major disability) and 49 patients (17.5%) experienced vascular events. After multivariate adjustment, serum cystatin C was significantly associated with an increased risk of the combined outcome of death and major disability (OR=4.51, P = 0.006). Adding serum cystatin C quartiles to a model containing conventional risk factors improved the predictive power for the combined outcome of death and major disability (continuous net reclassification index 43.88%, P < 0.001; categorical net reclassification index 9.15%, P = 0.013; integrated discrimination improvement 2.31%, P = 0.025). Similar phenomena were also observed in major disability and vascular events. Conclusion: Higher levels of serum cystatin C in AIS patients after IVT were independently associated with increased risks of poor functional outcomes and vascular events, especially combining conventional risk factors, suggesting that serum cystatin C might improve risk prediction for poor prognosis in AIS patients receiving rt-PA treatment.

Objective: Dyskinesia is the most common motor complication in advanced Parkinson’s Disease (PD) and has a severe impact on daily life. But the mechanism of dyskinesia is still poorly understood. This study aims to explore risk factors for disabling dyskinesia in PD and further analyze the Vesicular Monoamine Transporter 2 (VMAT2) distribution (labeled with 18F-AV133) in the corpus striatum and the 18F-fluorodeoxyglucose (18F-FDG) metabolism of different brain regions by PET-CT. Methods: This is a cross-sectional study involving 135 PD patients. They were divided into disabling dyskinesia group (DD group, N=22) and non-dyskinesia group (ND group, N=113). All the patients were agreed to undergo PET-CT scans. Clinical data were analyzed between two groups by using multivariate logistic regression analysis, and risk factors for disabling dyskinesia were then determined. The standard uptake value ratios (SUVr) of 18F-AV133 in the corpus striatum and the 18F-FDG metabolism of different brain regions were identified and calculated by the software. Results: 16.3% patients have disabling dyskinesia. DD group were more likely to have longer Disease Duration, higher Hoehn-Yahr degree, more severe clinic symptoms, more frequent sleep behavior disorder, and higher levodopa dose equivalency than ND group (P < 0.05). After adjusting confounding factors by multivariate logistic regression, DD group had longer PD duration and high levodopa dose equivalency compared with ND group (P < 0.05). There is no significant difference between the VMAT2 distribution (labeled with 18F- AV133) in the putamen and caudate between two groups. And the 18F-FDG metabolic changes in cortical and subcortical regions did not show a significant difference between the two groups either (P > 0.05). Conclusion: Long PD duration and high levodopa dose equivalency were two independent risk factors for disabling dyskinesia in PD patients. Compared to non-dyskinesia PD patients, there was no significant dopamine decline of the nigrostriatal system in disabling dyskinesia PD patients. Activities of different brain regions were not different between the two groups by 18F-FDG PETCT.

Background: Primary intraventricular hemorrhage (PIVH) is a rare type of Intracerebral Hemorrhage (ICH), which is poorly understood. This study aimed to investigate gender differences in patients' characteristics, management and outcome at discharge and 90 days after PIVH. Methods: Consecutive patients with PIVH from a single center in China were enrolled over a 7- year period. Gender differences in demographics, risk factors, etiological subtypes, treatment, and outcomes were examined. The logistic regression models were used in the study to identify the predictors of poor outcome. Results: In total, 174 patients were analyzed, and 77 (44.3%) of them were women. Women with PIVH were younger (p = 0.047), with lower systolic and diastolic blood pressure (p = 0.02 and p = 0.004, respectively). They had more cases caused by Moyamoya disease (p = 0.038). There were fewer patients with hypertension (p = 0.008), smoking (p<0.001), chronic alcoholism (p<0.001), harbored lower hemoglobin (p<0.001) and Absolute Monocyte Count (AMC) (p = 0.04) at admission compared with men. There were no differences between female and male patients regarding the mortality and poor outcome in the multivariable-adjusted models ((OR = 0.57; 95% CI, 0.15-2.14) and (OR = 0.86; 95% CI, 0.32-2.37), respectively). In subgroup analysis after adjustment, the gender specific independent predictors for unfavorable outcome were higher with a Graeb score (OR = 1.78; 95% CI, 1.01-3.13) or AMC (OR = 9.66; 95% CI, 1.20-12.87) in women, and lower Glasgow coma scale (GCS) score (OR = 0.64; 95% CI, 0.47-0.87) or acute hydrocephalus (OR = 0.17; 95% CI, 0.03-0.86) in men. Conclusion: Women with PIVH exhibit some distinctive baseline features compared with men. The gender difference of the PIVH does not appear to affect the neurological outcome. The predictors of poor outcomes are Graeb score and AMC in women and GCS score and acute hydrocephalus in men.

Background and Purpose: Cloudy white matter lesions are associated imaging features of internal jugular venous stenosis (IJVS). However, the mechanism of the IJVS associated cloudy white matter lesions is still unclear. This study aims to evaluate blood-brain barrier integrity of the patients with IJVS. Materials and Methods: A total of 45 eligible patients with IJVS confirmed by computed tomography venography (CTV) and 45 healthy controls were enrolled into this study. The levels of serum MMP-9 and the markers of tight junctions, including occludin and ZO-1 obtained from IJVS patients and control group were tested by enzyme-linked immune-sorbent assay and compared. Results: Both the levels of serum MMP-9 (0.2ng/ml) and occludin (0.05ng/ml) in IJVS group were higher than in the control group (0.01ng/ml vs. 0 ng/ml, all p<0.001). While, the levels of serum ZO-1 showed no statistical significance between the two groups (0.55ng/ml vs 0.735ng/ml, P=0.34). The levels of serum MMP-9 between the subset with or without white matter lesions in IJVS group showed a significant difference (0.22 [0.06, 0.43] vs. 0.01 [0.01, 0.06], P =0.019). Conclusion: BBB disruption may participate in the formation of IJVS-associated white matter lesions; the mechanism of BBB disruption may involve MMP-9 and occludin.

Background: Single Nucleotide Polymorphisms (SNPs) in the Erythropoietin (EPO) promoter region have been shown to influence EPO protein expression, and high blood levels of EPO are associated with an increased risk of brain injury in very preterm infants. Here, we investigated the genotype distributions and association of three EPO gene polymorphisms (rs1617640, rs551238, and rs507392) with the risk of brain injury in preterm infants. Methods: 304 preterm infants with a gestational age of 28 to 34 weeks were enrolled in this study. Brain injury was evaluated by brain ultrasound and MRI examination. EPO gene Single- Nucleotide Polymorphisms (SNPs) were genotyped by the Agena MassARRAY system, and their association with brain injury susceptibility in preterm infants was analyzed. Results: EPO polymorphism rs551238 showed a significant difference in the genotypic distributions between the brain injury group and the control group, and was significantly correlated with reduced susceptibility to brain injury in preterm infants according to the results obtained from both the additive model (OR = 0.520, 95% CI: 0.339-0.799, P = 0.003) and the dominant model (OR = 0.523, 95% CI: 0.332-0.853, P = 0.009). EPO polymorphisms rs1617640 and rs507392 did not meet the Hardy-Weinberg equilibrium in the study population (P < 0.05) and were, thus, not subjected to further analysis for their impacts on brain injuries. Conclusion: The “C” allele of rs551238 was correlated with a reduced risk of brain injury in preterm infants which may serve as a potential marker for brain injury prediction in preterm infants.

Background and Objective: Vitamin D deficiency is internationally recognized among the potentially modifiable risk factors for ischemic cardio-cerebrovascular diseases. However, the association between vitamin D deficiency and stroke morbidity or mortality remains insufficiently known. Our aim is to investigate their relevance to 25-hydroxyvitamin D [25(OH) D] levels and clinical severity and outcome after 3 months in first-ever ischemic stroke. Methods: Retrospective analysis of 356 consecutive patients in first-ever ischemic stroke between 2013 and 2015. Serum 25(OH) D levels were measured at baseline. Stroke severity was assessed at admission using the National Institutes of Health Stroke Scale (NIHSS) score. Functional outcome after 3 months of onset was evaluated using the modified Rankin scale (mRS). Results: Among the 356 enrolled patients, HbA1c was higher in insufficiency/deficiency group than that in the sufficiency group (6.3 ± 1.7 vs. 5.9 ± 1.1, p =0.015). The hospital stay was longer in insufficiency/deficiency group than that in the sufficiency group (11 (8-17) vs. 9.5 (7-13), p = 0.035). There was a significant inversed trend between serum 25(OH) D levels and hospital stay (OR 0.960, P = 0.031), using logistic regression. Conclusion: 25(OH)D levels are associated with glucose homeostasis, 25(OH) D contributes to increase the length of hospital stay. Low serum 25-OHD level is an independent predictor for hospital stay in first-ever ischemic stroke. Vitamin D deficiency did not predict functional outcome in the span of 3 months.

Background: Reducing hospital readmissions for stroke remains a significant challenge to improve outcomes and decrease healthcare costs. Methods: We analyzed 10,034 adult patients with ischemic stroke, presented within 24 hours of onset from a hospital-based stroke registry. The risk factors for early return to hospital after discharge were analyzed using multivariate logistic regression and classification and regression tree (CART) analyses. Results: Among the study population, 277 (2.8%) had 3-day Emergency Department (ED) reattendance, 534 (5.3%) had 14-day readmission, and 932 (9.3%) had 30-day readmission. Multivariate logistic regression revealed that age, nasogastric tube feeding, indwelling urinary catheter, healthcare utilization behaviour, and stroke severity were major and common risk factors for an early return to the hospital after discharge. CART analysis identified nasogastric tube feeding and length of stay for 72-hour ED reattendance, Barthel Index (BI) score, total length of stay in the Year Preceding the index admission (YLOS), indwelling urinary catheter, and age for 14-day readmission, and nasogastric tube feeding, BI score, YLOS, and number of inpatient visits in the year preceding the index admission for 30-day readmission as important factors to classify the patients into subgroups. Conclusion: Although CART analysis did not improve the prediction of an early return to the hospital after stroke compared with logistic regression models, decision rules generated by CART can easily be interpreted and applied in clinical practice.

Background: Studies have shown the relationship between neuroinflammation and depressive- like parameters. However, research still has not been carried out to evaluate neuroinflammation in the neonatal period and psychiatric disorders in adulthood. Objective: To verify the association between neonatal immune activation and depressive-like parameters in adulthood using an animal model. Methods: Two days old C57BL/6 animals were exposed to lipopolysaccharides (LPS) or phosphate- buffered saline (PBS). When the animals were 46 days old, they received PBS or Imipramine at 14 days. At 60 days, the consumption of sucrose; immobility time; adrenal gland and the hippocampus weight; levels of plasma corticosterone and hippocampal Brain-derived neurotrophic factor (BDNF) were evaluated. Results: It was observed that the animals exposed to LPS in the neonatal period and evaluated in adulthood decreased the consumption of sucrose and had reducted hippocampus weight. Also, the exposed animals presented an increase of immobility time, adrenal gland weight and plasma levels of corticosteroids. The use of imipramine did not only modify the decreased hippocampal weight. On the other hand, there were no alterations in the BDNF levels in the hippocampus with or without the use of imipramine. Conclusion: These results suggest that neonatal immune activation may be associated with depressive- like parameters in adulthood. It is believed that endotoxemia may trigger physiological and behavioral alterations, increasing vulnerability for the development of depression in adulthood.

Background: MicroRNAs (miRNA) are known to play a key role in the etiology and treatment of epilepsy through controlling the expression of gene. However, miR-125a-5p in the epilepsy is little known. Epilepsy in rat models was induced by Pentylenetetrazol (PTZ) and miR- 125a-5p profiles in the hippocampus were investigated in our experiment. Also, the relationship between miR-125a-5p and calmodulin-dependent protein kinase IV (CAMK4) was identified and the related mechanism was also illustrated. Methods: The miR-125a-5p mRNA expression levels were evaluated by quantitative real time polymerase chain reaction (qRT-PCR). Western Blot (WB) was used to analyze the CAMK4 protein expression levels. Seizure score, latency and duration were determined based on a Racine scale. The enzyme-linked immunosorbent assay (ELISA) was used to analyze the inflammatory factor expression. The relationship between miR-125a-5p and CAMK4 was detected through dual luciferase assay. Results: Downregulation of miR-125a-5p was observed in the hippocampus of PTZ-induced epilepsy rats. The overexpression of miR-125a-5p attenuated seizure and decreased inflammatory factor level in the hippocampus of PTZ-induced rats. The miR-125a-5p alleviated epileptic seizure and inflammation in PTZ-induced rats by suppressing its target gene, CAMK4. Conclusion: miR-125a-5p may represent a novel therapeutic treatment for PTZ-induced epilepsy by preventing the activation of CAMK4.

Objective: Dysregulation of miR-34a has been reported for its implication in neuronal development. This study aims to explore the effect and possible mechanism of miR-34a on neuron apoptosis induced by Spinal Cord Injury (SCI). Materials and Methods: SCI model was established using Allen's weight-drop method and rats in the sham group were performed with laminectomy without weight-drop injury. Basso Bcattie Bresnahan (BBB) rating scale was applied to evaluate the locomotor function of rats. Pathological changes of spinal cord tissues in SCI rats were observed after hematoxylin and eosin (HE) staining. Rats were separately injected with miR-34a agomir, miR-34a agomir NC, si-CD47 and si- CD47 NC before their spinal cord tissues were collected for terminal-deoxynucleoitidyl Transferase Mediated nick end labeling (TUNEL) staining. Expressions of miR-34a, si-CD47, apoptosis related proteins and AKT pathway related proteins were measured by quantitative reverse transcription- polymerase chain reaction (qRT-PCR) and western blot. Results: SCI rat models were successfully established evidenced by decreased BBB scores and HE staining. Injection of miR-34a agomir and/or si-CD47 could suppress neuron cell apoptosis, with deceased apoptotic index (AI) and pro-apoptotic protein (cleaved caspase-3 and Bax) levels, and increased expressions of anti-apoptotic proteins (Bcl-2 and Mcl-1). Phosphorylated levels of phatidylinositol 3-kinase (PI3K) and AKT were further increased in rats injected with miR-34a agomir and si-CD47, compared with miR-34a agomir or si-CD47 injection alone. Conclusion: MiR-34a can downregulate CD47 expression to activate PI3K/AKT signal pathway, and thus inhibit SCI induced spinal neuron apoptosis.

Purpose: Research has shown that exposure to anesthesia might increase the risks of cognitive impairments and learning difficulties. MiR-125b-5p contributed to anesthesia-induced hippocampal apoptosis. However, the role of miR-125b-5p in sevoflurane-induced cognitive impairments remains unclear. Methods: Firstly, sevoflurane was used to establish a rat model and cognitive impairment was detected by the Morris water maze (MWM) test. The hippocampus was observed by HE staining. The lentivirus-miR-125b-5p antagomiR was transfected into rats to decrease miR-125b-5p. The interaction between miR-125b-5p and LIM domain kinase 1 (LIMK1) was confirmed by the luciferase reporter assay. The mRNA and expression levels of related genes and mRNA were examined by the Quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) and western blot. Results: Sevoflurane induced the cognitive dysfunction presenting with longer latency time and few platform crossings in rats. Moreover, miR-125b-5p was observed to be up-regulated in both sevoflurane-anesthesia rats and sevoflurane-treated SH-SY5Y cells. More importantly, a decrease in miR-125b-5p could prevent sevoflurane-induced hippocampal apoptosis and inflammation in rats. Moreover, LIMK1 was the target gene of miR-125b-5p. Interestingly, si-LIMK1 could restore the sevoflurane-induced cell apoptosis in SH-SY5Y cells, which was alleviated by miR-125b-5p inhibitor. Finally, the miR-125b-5p inhibitor shortened the time to find the platform and increased the number of platform crossings compared to sevoflurane-anesthesia rats in the Morris water maze test. At the same time, the expression of LIMK1 was dramatically increased. Conclusion: Altogether, these findings suggested that miR-125b-5p inhibitor could protect against the sevoflurane-induced cognitive impairments by targeting LIMK1.

Background: Although vitamin D has several noncalcemic functions particularly on nervous system, its neuroregenerative roles on ischemic peripheral nerve injury has not been reported. In this study, it was aimed to investigate the effect of vitamin D3 after epineurial devascularization of the sciatic nerve. Methods: Forty adult female Wistar rats were randomly divided into four groups: Group 1 (Control), Group 2 (Sham-operated), Group 3 (Epineurial devascularization + vitamin D3 treatment), Group 4 (Epineurial devascularization + vehicle treatment). Recovery of the sciatic nerve was analyzed by functional (sciatic functional index, pinch test and biochemical analyses) and morphological (electron microscopic analysis and wet muscle weight analysis) methods. Results: Comparison of the data revealed that vitamin D3 administration had a beneficial effect on regeneration after epineurial devascularization. Conclusion: We suggest that vitamin D3 is an effective agent in the prevention of ischemic peripheral nerve insults.