Current Neurovascular Research - Volume 9, Issue 2, 2012

Full text available.

Measurements of the redox balance after the ischemic stroke occurrence might be useful to monitor the outcome of patients who suffered an ischemic stroke in terms of stroke recurrence and other vascular events. For this purpose, fifteen patients (mean age 71.40±2.50 years) with a first-ever ischemic stroke were included in the study within 30 days of stroke onset. Stroke severity was evaluated according to the National Institutes of Health Stroke Scale (NIHSS). Redox balance was assessed by measuring plasma amount of total peroxidative by-products, nitrite/nitrate metabolites (NOx), as expression of nitric oxide (NO) plasma bioavailability, total plasma antioxidant capacity (TEAC), Cu/Zn Superoxide Dismutase (Cu/Zn SOD) activity, serum urate concentration and autoantibodies against ox-LDL (OLAB) serum level. Total cholesterol, triglycerides, high density lipoprotein-cholesterol (HDL-C) and low density lipoprotein-cholesterol (LDL-C) were also measured. Fifteen apparently healthy controls (mean age 70.28±2.03 years) were investigated to compare redox markers. Stroke patients had higher plasma values of total peroxidative by-products, NOx stable metabolites and of total cholesterol, triglycerides, and LDL-C than controls (P<0.05). No differences in OLAB levels, Cu/Zn-SOD activity, serum urate concentration, and plasma HDL-C amount were found in stroke patients when compared to controls. Total plasma antioxidant capacity was lower in stroke patients than in controls. NOx values correlated positively with the NIHSS score in stroke patients (r=0.668; P=0.0065). The observed presence of redox unbalance in stroke patients could represent an early indicator of diffuse endothelial activation during which patients may be at increased risk of stroke recurrence and other vascular events.

Wnt1 inducible signaling pathway protein 1 (WISP1/CCN4) is a CCN family member more broadly identified with development and tumorigenesis. However, recent studies have shed new light and enthusiasm on WISP1 as a novel target directed against toxic cell degeneration. Here we show WISP1 prevents apoptotic degeneration in primary neurons during oxidant stress through the activation of protein kinase B (Akt1), the post-translational maintenance of β-catenin integrity that is consistent with inhibition of glycogen synthase kinase-3β (GSK-3β), and the subcellular trafficking of β- catenin to foster its translocation to the nucleus. Interestingly, WISP1 autoregulates its expression through the promotion of β-catenin activity and may employ β-catenin to have a limited control over autophagy, but neuronal injury during oxidant stress as a result of autophagy appears portioned to a small population of neurons without significant impact upon overall cell survival. New strategies that target WISP1, its autoregulation, and the pathways responsible for neuronal cell injury may bring forth new insight for the treatment of neurodegenerative disorders.

We evaluated the protective effects of crocetin against angiogenesis induced by vascular endothelial growth factor (VEGF). Crocetin, the aglycone of crocin carotenoids, is found in saffron crocus (Crocus sativus L.) and gardenia fruit (Gardenia jasminoides Ellis). The effects of crocetin on VEGF-induced angiogenesis were examined by in vitro tube formation assays and following 14-day co-culture of human umbilical vein endothelial cells (HUVECs) and fibroblasts. The anti-angiogenic mechanism of crocetin was evaluated by examining its effects on VEGF-induced proliferation and migration of human retinal microvascular endothelial cells (HRMECs) and phosphorylation of p38. Vascular endothelial (VE)-cadherin, zonula occludens (ZO-1) and occludin, which are adherens and tight junction proteins, respectively, play a major role in the control of vascular permeability. Therefore, we tested effects of crocetin on adhesion molecule dissociation induced by VEGF. Crocetin significantly suppressed VEGF-induced tube formation by HUVECs and migration of HRMECs. It also significantly inhibited phosphorylation of p38 and protected VE-cadherin expression. These findings indicate that crocetin suppresses the VEGF-induced angiogenesis by inhibiting migration and that the inhibition of phosphorylated-p38 and protection of VE-cadherin expression may be involved in its underlying mechanism of action.

We recently demonstrated a dramatic up regulation of laminin expression within the blood vessels of brain regions vulnerable to excitotoxin mediated neuronal degeneration. Although this effect was clearly demonstrable at 2 days post kainic acid exposure, its expression at shorter and longer post-dosing intervals has not been reported. Therefore, a primary goal of the present study was to characterize the laminin labeling at intervals ranging from 4 hours to 2 months following i.p. injection of kainic acid. To better characterize the nature and possible underlying mechanism of action of the changes in laminin expression, both Fluoro-Jade C and GFAP immunohistochemistry were employed respectively at all survival intervals. At the shortest intervals examined (4hr, 8hr), Fluoro-Jade C positive cells could be detected in the hippocampus, thalamus, and piriform cortex. In these same regions, both vascular laminin and astrocytic GFAP expression were up regulated. At intermediate survival intervals (2, 5, 14, and 21 days), the respective labeling of degenerating neurons, astrocytes and capillaries were all maximal. Morphologically, Fluoro-Jade C labeled degenerating neurons were labeled in their entirety, GFAP positive astrocytes appeared hypertrophic and blood vessels took on a fragmented appearance. Hypertrophied GFAP positive astrocytes were conspicuous around periphery of the lesion but absent within the core of the lesion at these times. At longer survival intervals (1-2 months), the number of FJ-C labeled degenerating neurons was greatly reduced, while GFAP staining essentially returned to base line and laminin expression remained noticeably elevated, although the vessels appeared to be intact morphologically. These data allow for speculation on possible mechanisms underlying these events.

Venous echo-color-Doppler (ECD) showed that chronic cerebrospinal venous insufficiency (CCSVI) syndrome is related to multiple sclerosis (MS). Study aims were to assess interobserver variability in ultrasound evaluation of MS patients and to relate echo-markers to MS clinical symptoms and the disability degree. 277 MS patients (117 men, mean age 43.05+10.04 years) admitted to the Neurology Department of Bari University General Hospital, underwent clinical, Expanded Disability Status Scale (EDSS) evaluation, and a cerebro-venous system ECD evaluation. Two operators reevaluated 32 patients to calculate interobserver variability. McNemar test confirmed the procedure reproducibility between two operators (p=ns). Septa/membranes correlated with deep cerebral veins reflux [right: 16% absence vs. 58% presence, p<0.0001; left: 26% vs. 50%, p<0.0001]; their absence in Primary Progressive (PP) MS form [right: 11% vs. 2%, p<0.001; left: 12% vs. 2%, p<0.001]. Internal jugular veins (IJVs) reflux absence was in Relapsing-remitting (RR) form [right: 60% vs. 74%, p=0.036; left: 56% vs. 85%, p<0.0001] like hemodynamically significant stenosis [right: 57% vs. 69%, p=0.033; left: 49% vs. 73%, p<0.001] not present in PP [right: 11% vs. 2%, p<0.001; left: 10% vs. 3%, p=0.009]. A supine IJVs blocked flow was related to the EDSS class [right: 4.8±1.5 vs. 5.4±1.4, p=0.006; left: 4.7±1.6 vs. 5.5±1.2, p<0.0001]; its absence was linked to RR [right: 60% vs. 76%, p=0.016; left: 58% vs. 79%, p<0.001]. ECD has an important value in MS patients with IJV anomalies detection and a good interobserver procedure reproducibility. MS is associated with CCSVI, although further studies are needed.

Elevated serum bilirubin was prevalent in the acute ischemic stroke (AIS), which was induced in response to oxidative stress and could display the intensity of oxidative stress. As more severe stroke is linked with higher level of oxidative stress, we hypothesized that bilirubin may be associated with the severity of stroke. In this study, bilirubin and other biochemical indexes were measured in 531 enrolled patients with AIS, and NIH Stroke Scale (NIHSS) scores were assessed simultaneous with blood collection. The association between bilirubin and the severity of stroke was performed by Spearman correlation analyze, and the level-risk relationship of bilirubin in different level of NIHSS score was performed through Multinomial logistic regression analysis. We performed multivariable logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) of severe stroke dichotomized as NIHSS≥8 with adjustment for other stroke risk factors, the level-risk relationship of severe stroke in different level of bilirubin was also performed through Multinomial logistic regression analysis. We found that NIHSS score was significantly positively correlated with both serum direct bilirubin (Dbil, R=0.229 and P=0.000) and total bilirubin (Tbil, R=0.224 and P=0.000), higher level of serum bilirubin linked to the higher NIHSS score with OR(95% CI) in upper level of NIHSS score group was 1.12(1.01-1.24), 1.23(1.11-1.36), 1.31(1.15-1.51) in Dbil and 1.01(0.99-1.31), 1.05(1.03-1.08), 1.07(1.03-1.11) in Tbil compared to the lowest level group. In unadjusted or adjusted logistic regression analyses, serum Dbil and Tbil still have a significant association with the severe stroke. When both the Dbil and Tbil concentrations were grouped into 4 levels, participants with higher levels of bilirubin showed higher risk with severe stroke compared with the lowest level of bilirubin, with OR(95% CI) 1.881(1.04-3.404) of Dbil in level 3 and 3.702(1.979-6.927) of Tbil, 3.352(1.572-7.147) of total bilirubin in level 4. As a conclusion, serum bilirubins were in significant correlation with severity of AIS, which may be served as useful markers to reflect the degree of illness.

Important advances have been made within in past few years in the treatment of glioma, however, the longterm prognosis after resection of glioma remains unsatisfactory as a result of a high incidence of recurrence. To solve this problem, many biologic therapies have been investigated. In the present study, we report a nanoparticle with properties for dual targeting of tumor cells and the neovasculature. The nanoparticle comprises encoding vasohibin and RGD 12-mer cationic peptide RKKRRQRRRRGD (Tat49-57RGD) peptides, which a nuclear nanoparticle within an extranuclear peptide envelope. Our results demonstrate that the nanoparticle could prevent tumor angiogenesis and inhibit tumor growth via attenuating neovasculature formation and inducing tumor apoptosis. Therefore, the dual targeting strategy of tumor cells and neovasculature represents an integrative approach in glioma therapy. This can be extended to additional agents to target multiple signal pathways or distinct tumor compartments.

Nimodipine improved outcome in patients with subarachnoid hemorrhage (SAH) although hypotension limited the dose that could be administered systemically. Subarachnoid delivery of nicardipine or nimodipine may be more efficacious. We tested the efficacy of cisternal application of sustained release nicardipine and nimodipine in SAH in monkeys and dogs, respectively. SAH was created in 13 cynomolgus macaques by placement of autologous blood clot around right middle cerebral, anterior cerebral, and internal carotid arteries. Placebo poly-D,L-lactide coglycolide (PLGA), nicardipine PLGA or mibefradil PLGA was inserted in the clots. Catheter and computed tomography angiography (CTA) were performed at baseline and 7 days later (day 7). Cerebral infarction was assessed on day 7 by magnetic resonance imaging. Six dogs underwent baseline angiography and injection of autologous blood plus PLGA or nimodipine-loaded PLGA microparticles into the cisterna magna. Blood injection was repeated 2 days later and angiography 7 and 14 days later. Animals were euthanized and brains were examined histologically. Cerebrospinal fluid and serum nimodipine concentrations were measured. Nicardipine, but not mibefradil PLGA decreased vasospasm in monkeys (paired t-tests) although there was no significant effect on infarctions see on MRI. In dogs, nimodipine-PLGA produced high local concentrations of nimodipine that were associated with reduced basilar artery vasospasm. No untoward histological effects were observed. There was no reduction in microthrombi in animals treated with nimodipine PLGA compared to placebo PLGA. Site-specific, sustained release formulations of dihydropyridines can deliver high concentrations to the cerebrospinal fluid without causing systemic side effects, and may reduce angiographic vasospasm after SAH. Since nimodipine improves outcome in patients with SAH without necessarily preventing vasospasm, further studies are warranted.