Current Neurovascular Research - Volume 15, Issue 3, 2018

Background: In animal models, flow-loading is a necessary and sufficient hemodynamic factor to express the Cerebral Aneurysm (CA) phenotype. Using a rat model, this study characterizes the molecular events that comprise the cerebral arterial response to flow-loading and reveals their significance relating to the CA phenotype. Objective: To characterize the molecular events that underlie expansive remodeling of cerebral arteries in two genetically distinct inbred rat strains with differential susceptibility to flow-dependent cerebrovascular pathology. Methods: Thirty-two rats underwent bilateral common carotid artery ligation (BCL) (n=16) or Sham Surgery (SS) (n=16). Nineteen days later, vertebrobasilar arteries were harvested, histologically examined and analyzed for mRNA and protein expression. Flow-induced changes in histology, mRNA and protein expression were compared between BCL and SS rats. Differences between aneurysm-prone (Long Evans, LE) and resistant (Brown Norway, BN) strains were evaluated. Results: Basilar Artery (BA) medial thickness/luminal diameter ratio was significantly reduced in BCL rats, without significant differences between LE (2.02 fold) and BN (1.94 fold) rats. BCL significantly altered BA expression of mRNA and protein but did not affect blood pressure. Eight genes showed similarly large flow-induced expression changes in LE and BN rats. Twenty-six flow responsive genes showed differences in flow-induced expression between LE and BN rats. The Cthrc1, Gsta3, Tgfb3, Ldha, Myo1d, Ermn, PTHrp, Rgs16 and TRCCP genes showed the strongest flow responsive expression, with the largest difference between LE and BN rats. Conclusions: Our study reveals specific molecular biological responses involved in flow-induced expansive remodeling of cerebral arteries that may influence differential expression of flowdependent cerebrovascular pathology.

Background: Epilepsy is a chronic neurological disorder affecting an estimated 50 million people worldwide. Emerging evidences have accumulated over the past decades supporting the role of inflammation in the pathogenesis of epilepsy. Curcumin is a nature-derived active molecule demonstrating anti-inflammation efficacy. However, its effects on epilepsy and corresponding mechanisms remain elusive. Objective: To investigate the effects of curcumin on epilepsy and its underlying mechanism. Method: Forty Sprague Dawley rats were divided into four groups: (1) control group; (2) Kainic Acid (KA)-induced epilepsy group; (3) curcumin group; and (4) curcumin pretreatment before KA stimulation group. Morris water maze was utilized to assess the effect of curcumin on KA-induced epilepsy. The hippocampi were obtained from rats and subjected to western blot. Immunohistochemistry was conducted to investigate the underlying mechanisms. Results: Rats received curcumin demonstrated improvement of recognition deficiency and epilepsy syndromes induced by KA. Western blot showed that KA stimulation increased the expression of IL-1β and NLRP3, which were reduced by curcumin treatment. Further investigations revealed that curcumin inhibited the activation of NLPR3/inflammasome in epilepsy and reduced neuronal loss in hippocampus. Conclusion: Curcumin inhibits KA-induced epileptic syndromes via suppression of NLRP3 inflammasome activation; therefore, offers a potential therapy for epilepsy.

The association of poor outcome and mortality with low levels of hemoglobin (Hb) and hematocrit (HcT) in patients admitted after acute Ischemic Stroke (IS) was recently demonstrated. The mechanisms behind this still remain unclear. Our study aims to find out whether mRNA expressions and plasma concentrations of endothelin-1 (ET-l), endothelin-2 (ET-2) and endothelin-3 (ET-3) remain different in IS sufferers with low HcT and Hb levels in comparison with those whose HcT i Hb levels during a severe IS episode remain within the norm. The study included 60 patients treated consecutively for first-time IS. The assessment of mRNA gene expression and plasma concentration of ET-1, ET-2, ET-3 was conducted in the first, third and seventh day following the onset of stroke using qRT-PCR method and ELISA tests. We demonstrated that patients whose initial HcT and Hb levels were below the norm presented a deeper neurologic deficit on 1, 3 and 7 day following stroke with noticeable improvement no earlier than between day 3 and 7. We also found a negative correlation between the initial HcT and Hb and concentration of plasma ET-1 on the same days. The patients whose HcT and Hb levels were within normal limits showed a significant improvement in their neurologic condition on each consecutive day of the observation. Reduced levels of Hb and HcT combined with an increased plasma concentration of vasoconstrictive endothelin-1 are strongly associated with poor outcome and high mortality in acute ischemic stroke.

Background: We compared the clinical outcomes of low and standard dose recombinant tissue Plasminogen Activator (rtPA) treatment in Acute Ischemic Stroke (AIS) patients receiving Endovascular Mechanical Thrombectomy (EVT). Methods: Between April 01, 2015 and September 30, 2017, all AIS patients admitted to the Linkou and Chiayi Chang Gung Memorial Hospital were retrospectively reviewed. Patients with large vessel occlusions, who underwent bridging therapy with rtPA and EVT, were further enrolled. The enrolled patients were categorized into low (0.6-0.7 mg/kg; LD) or standard dose (0.9 mg/kg; SD) group based on the dose of rtPA they received. Baseline characteristics, reperfusion status, and clinical outcomes were compared between the two groups. Results: Forty-two patients were enrolled in the final analyses, including 13 in the LD and 29 in the SD group. In all groups analyzed, the frequencies of moderate to severe and severe stroke at discharge were significantly decreased compared to those at stroke onset (p < 0.01). Compared to the SD group, patients of the LD group had a similar rate of mortality (LD vs. SD; 0% vs. 3.4%, p = 1.00), and comparable frequencies of functional independence at 3 months after stroke onset (LD vs. SD; 33.3% vs. 44.8%, p = 0.50). The rates of symptomatic intracerebral hemorrhage were also similar between the two groups (LD vs. SD; 0% vs. 6.9%, p =1.00). Conclusions: Compared to standard dose treatment, low dose rtPA may have similar clinical efficacy and safety outcomes in AIS patients receiving bridging therapy.

Background: This study was to investigate the neuroprotective effect of long noncoding RNAs Metastasis associated lung adenocarcinoma transcript-1 (lncRNA MALAT-1) in Spinal Cord Ischemic/Reperfusion Injury (SCIRI). Methods: Quantitative real-time PCR (RT-qPCR) was used to examine the expressions of MALAT1, miR-204 and Bcl-2, while western blot was performed to examine Bcl-2. Besides, apoptosis was evaluated by the percentage of cell viability and apoptotic cells. Neurological evaluation was performed by measuring hindlimb locomotor function. Results: The expression of MALAT1 and Bcl-2 was decreased, while miRNA-204 (miR-204) was up-regulated in rats SCIRI model and neurocyte lines under hypoxic conditions. Oxygen, Glucose Deprivation (OGD) promoted apoptosis of neurocytes, downregulated MALAT1 and Bcl-2 and elevated miR-204 expression, however, overexpression of MALAT1 notably reversed this trend. Nevertheless, knockdown of MALAT1 increased cell apoptosis, decreased MALAT1 and Bcl-2 but upregulated miR-204. MALAT1 overexpression-induced anti-apoptosis and knockdowninduced pro-apoptosis were obviously reversed by synchronously overexpression and knockdown of miR-204, respectively. MALAT1-treated SCIRI rats exhibited lower Motor Deficit Index (MDI) scores, higher levels of MALAT1 and Bcl-2 expression and lower miR-204 expression. Conclusion: Our data suggested that MALAT1 exerted neuroprotective effect in a rat model of SCIRI by regulating miR-204.

The aim of this study is to evaluate whether cerebral inflow and outflow abnormalities, assessed by the means of a validated ultrasound model, could be associated with Sudden Sensorineural Hearing Loss (SSNHL). According to Clark, a total of 42 patients affected by severe SSNHL and 19 healthy volunteers matched by gender without any history of sudden hearing impairment have been included in this study. Patients and controls underwent EchocolorDoppler assessment of brain hemodynamics. All subjects affected by SSNHL were also assessed with Auditory Brainstem Responses (ABR) and Magnetic Resonance Imaging (MRI) in order to exclude retrocochlear pathology. The head inflow through the common carotid artery was practically equivalent between groups, but at the level of the carotid bifurcation, the external carotid artery showed a highly significant flow rate in SSNHL 5.4±2 vs 3.9±1.1 ml/s in controls (p=0.01). The brain inflow was similar between patients and controls, but interestingly the flow rate of the vertebral artery was significantly reduced in SSNHL 1.6±0.8 vs 2.8±0.9 ml/s (p=0.01). The brain outflow was found significantly restricted at the level of the jugular outlet 6.6±6 vs 9.9±6 ml/s (p=0.002); consequently, the collateral flow index was significantly increased in SSNHL (p=0.001). The present study shows a discrepant distribution of the brain inflow which seems to penalize the posterior segments of the Willis polygon in patients affected by severe SSNHL. In addition, our study confirms the presence of chronic cerebrospinal venous insufficiency in SSNHL with significant activation of venous collateral circulation.

Aims: C-reactive protein is an established marker of inflammation that can impair the protective function of High Density Lipoprotein Cholesterol (HDL-C). The combined effect of Creactive protein and HDL-C on long-term outcomes in patients with stroke remains uncertain. Methods: A total of 3124 acute ischemic stroke subjects from the China Antihypertensive Trial in Acute Ischemic Stroke (CATIS) were included in this analysis. Participants were divided into four groups according to CRP and HDL-C levels on admission. The primary outcome was a combination of death and major disability (modified Rankin Scale score ≥3) at one year after stroke. Results: Compared to participants with low CRP/ high HDL-C, adjusted odd ratios for primary outcome for those with low CRP /low HDL-C, high CRP /high HDL-C and high CRP /low HDL-C were 1.06(0.81-1.39),1.78(1.31-2.41) and 2.03(1.46-2.80), respectively, after multiple adjustments. Adding serum CRP and HDL-C status to a model containing conventional stroke risk factors significantly improve risk reclassification for the combined outcome of death and major disability (NRI: 6.85%, P=0.005; IDI: 2.57%, P=0.002). Moreover, no interaction was observed between CRP and HDL-C in relation to stroke outcomes (P-interaction >0.05 for all). Conclusions: High CRP with low HDL-C levels was associated with death and major disability within one year after ischemic stroke. The findings suggest that the ischemic patients with both high CRP and low HDL-C should be treated with reducing CRP and promoting HDL-C levels.

Aim: The aim of the present work was to explore the outcome of combination of Calcineurin (CaN) inhibitor and Protein Kinase A (PKA) activator, in mouse models of experimental dementia. Methods: Cognitive deficits were induced in mice by injecting Streptozotocin (STZ) intracerebroventricularly (i.c.v.); on the other hand aged animals were procured as a natural model of dementia. To assess cognitive function of mice Morris water maze (MWM) test was utilized; various biochemical studies and histopathological studies were also carried out. Results: STZ injection and aging resulted in significant development of cognitive deficits; along-with enhancement of Myeloperoxidase (MPO) levels, Thiobarbituric Acid Reactive Species (TBARS), Acetylcholinestrase (AChE) activity, and reduced Glutathione (GSH) levels. Histopathological studies demonstrated pathological changes such as amyloid deposition and severe neutrophilic infiltration in brains of these mice. Donepezil /combination of Tacrolimus and Forskolin treatment markedly improve cognitive function, biochemical parameters, and histopathological alterations in STZ treated and aged mice. Conclusion: The outcome reveals that combination of CaN inhibitor and PKA activator has significantly alleviated memory dysfunction, biochemical alteration and histopathological changes quiet comparable to Donepezil. It has been inferred that combination of CaN and PKA can be served as an important target in dementia.

Background: Glioma is a type of tumor that starts in the glial cells of brain and spine. However, the underlying molecular mechanisms of miRNAs dysregulation in glioma initiation and progression is largely unclear. Objective: To further understand the molecular mechanism of miR-490-5P functions and how miR-490 regulated CCND1 function. Methods: The expression of miR-490-5P in glioma tissues and cells was measured by qRT-PCR and ISH. Cell transfection is responsible for miR-490-5P overexpression and knockdown. CCK-8 and clone formation assay are applicable to examine the capacity of glioma cells proliferation. Cell cycle analysis is used to test glioma cells cycle distribution with miR-490-5P overexpression or downregulation. Further, in vivo tumor exnograft studies are used to examine the effects of miR- 490-5P on glioma malignancy in vivo. Results: We found overexpression of miR-490 lead to glioma cells cycle arrest at G1 phase and decreased proliferation. Next-step functional assays showed miR-490 regulated CCND1 expression and manipulated giloma cells proliferation. Finally, negative regulation of miR-490 in CCND1 function was validated through in vivo nude mice tumorigenesis assay and IHC examination in glioma tissue. Conclusion: Overall, these results showed that epigenetic regulation of CCND1 via miR-490 was essential to glioma and provide a new insight into glioma diagnosis, treatment, prognosis and further translational investigations.

Background: While some randomized clinical trials have reduced the indications for cerebral revascularization in the secondary prevention of ischemic stroke, a distinct subset of patients with blood pressure augmentation dependent cerebrovascular insufficiency due to large vessel occlusions remains unaddressed. With the recent paradigm shifts in acute ischemic stroke care, the role of extracranial to intracranial (EC-IC) bypass must be re-addressed when endovascular intervention is not a feasible option. We submit a refined classification of cerebrovascular insufficiency with a category called Pressor-Dependent Cerebrovascular Insufficiency (PD-CVI) for whom EC-IC bypass may be indicated. Clinical Presentation: A 61-year-old female former smoker presented with one day of intermittent left faciobrachial weakness and was found to have middle cerebral artery and cervical internal carotid artery occlusions. On admission to the intensive care unit, she was found to have PD-CVI with an intravenous pressor dependent blood pressure threshold over which she had near resolution of her neurological deficits. With endovascular intervention precluded given the ICA occlusion, she underwent an urgent right sided EC-IC bypass. The procedure was without complication, with careful attention to maintaining hypertension perioperatively. She required no pressors postoperatively and was neurologically intact at three months post-operatively. Conclusion: With recent advances in acute ischemic stroke care, there remains a need for careful consideration of cerebral revascularization surgery in patients with evidence of PD-CVI who may be precluded from or failed endovascular intervention.

Chlamydia Pneumoniae (C. Pn) is an obligatory intracellular bacterium that is associated with respiratory tract infections like pneumonia, pharyngitis and bronchitis. It has also been implicated in cerebrovascular (stroke) as well as cardiovascular diseases. The most possible pathway via which C. Pn elicits its pathogenesis could be via activation of Human Vascular Smooth Muscle Cells (VSMCs) proliferation resulting in the stimulation of Toll-Like Receptor-4 (TLR-4) and/or phospho-44/42(p44/p42) Mitogen-Activated Protein Kinases (MAPK). It is also established that tyrosine phosphorylation of IQ domain GTPase-activating protein 1 (IQGAP1) also contributed to C. Pn infection-triggered Vascular Endothelial Cell (VEC) movements via the SRC tyrosine kinase inhibitor PP2 (4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine) resulting in angiogenesis. It is also proven that restricted inflammatory cell infiltrates as well as apoptosis have been linked to C. Pn or C. Pn-specific proteins in atherosclerotic plaques of patients with stroke. It is further an evidence that C. Pn enters the cerebral vasculature during the initial infection and worsen atherosclerosis either directly or indirectly. Chronic, persistent C. Pn infection is also capable of triggering the secretion of Chlamydial Heat Shock Protein 60 (cHSP60) in the vessel wall resulting in augmentation of inflammation. C. Pn also aids in the activation of explicit cell-intermediated immunity within plaques. Macrophages in the carotid plaques co-exist with CD4+ lymphocytes which are capable of triggering the release of pro-inflammatory cytokines resulting in the augmentation of atherogenic development during C. Pn infection. C. Pn actively participated in the modification of both histones H3 and H4 during chromatin analysis via the interleukin 8(IL-8) gene facilitator as well as conscription of nuclear factor kappa-B(NF-ΚB) or NF- ΚB/p65 complex and polymerase II (Pol II). This review, therefore, focuses on the crucial involvement of C. Pn in the pathogenesis of cerebrovascular events.