Current Neurovascular Research - Volume 15, Issue 2, 2018

Background: The purpose of the present study was to investigate the effects of Onjisaponin B (OB) in lipopolysaccharide (LPS)-induced cognitive deficits. Methods: The rats were divided into four groups: sham group, LPS group (the model group), LPS + OB (1 mg/kg) group and LPS + OB (2 mg/kg) group. OB was treated three days before surgery and thereafter continuously for 7 days. Three days later, rats were intracerebroventricularly injected with LPS. The levels of inflammatory cytokines and the capability of free radical scavenging in serum and hippocampus were determined after the LPS challenge. PC12 cells were divided into control group, LPS group (the model group), LPS + OB (10 μM) group, LPS + OB (20 μM) group, LPS + OB (40 μM) group, LPS + OB (2 mg/kg) + nicotinamide group. The cell viability was measured by MTT assay. The protein expressions of Sirt1, p-AMPK, AMPK, Nrf-2, HO-1, Bcl-2, Bax, caspase-9, caspase-3, p-IΚBα, IΚBα, p-NF-ΚBp65 and NF-ΚBp65 were detected by western blot analysis. Results: As a result, OB administration effectively relived the cognitive impairment, reduced the contents of IL-1β, IL-6, TNF-α, MDA and restored SOD activities of SOD in serum and hippocampus of LPS-induced rats. Furthermore, OB treatment improved cell viability, ameliorated the alterations of IL-1β, IL-6, TNF-α, MDA and SOD in the supernatant of LPS-induced PC12 cells. Of note, the expressions of Sirt1, Nrf-2, HO-1, Bcl-2 and p-AMPK were downregulated, while Bax, caspase-9, caspase-3 and the phosphorylations of IΚBα and NF-ΚBp65 in the LPS-stimulated hippocampus and PC12 cells were increased attributed to the LPS stimulation. Nevertheless, the conditions were significantly attenuated by OB treatment. In the LPS-induced PC12 cell, nicotinamide, a SIRT1 inhibitor, abrogated the beneficial effects of OB, as indicated by the antioxidant, anti-inflammatory and anti-apoptosis signaling. Conclusion: Based on the above evidence, our results demonstrated that OB was a potential therapeutic candidate for LPS-induced cognitive deficits.

Our previous work has indicated that miR-155 expression induces inflammatory responses in ischemic cerebral tissues. However, the delicate regulation of miR-155-modifed inflammatory responses has remained enigmatic. In the present study, we found that autophagy is induced by ischemia through miR-155 and involved in neural injury. Subsequently, miR-155- induced autophagy modifies inflammatory responses through regulating TLR4/NF-ΚB pathway in ischemic cerebral tissues. Thus, miR-155 elevated autophagy is detrimental for ischemic cerebral injury and miR-155-induced autophagy modulates inflammatory responses through activating TLR4/NF-ΚB pathway.

Background: Cyclophilin A plays a pathogenic role in the development and progression of atherosclerosis, which can be assessed by measuring carotid intima-media thickness. The primary aim of this study was to examine the interaction between plasma Cyclophilin A level and carotid intima-media thickness in patients with acute ischemic stroke. Method: Plasma concentration of Cyclophilin A was measured on admission in 66 consecutive patients who had been hospitalized for acute cerebral stroke and in 52 case-control subjects without a history of acute stroke. Subjects in both groups also underwent ultrasound B-mode imaging to measure the mean and maximum intima-media thickness of the carotid artery. Inflammatory biomarkers including high-sensitivity C-reactive protein and fibrinogen were also assessed. Results: We found that the plasma concentration of Cyclophilin A was significantly higher in patients with acute ischemic stroke (p = 0.042). Increased Cyclophilin A was also correlated with carotid intima-media thickness in the patient group (p < 0.001). Among the risk factors for cerebral stroke examined in this study, only hypertension was significantly associated with plasma Cyclophilin A level. Conclusion: Increased plasma Cyclophilin A levels might be involved in the pathophysiology of acute ischemic stroke and Cyclophilin A might serve as a biomarker in risk assessment of acute stroke patients.

Background: Endothelial Progenitor Cells (EPCs) have been suggested to be a therapeutic option in Acute Ischemic Stroke (AIS). Statins modulate endothelial function and preserve blood flow to tissue exposed to an ischemic insult. We tested the hypothesis that statins therapy might augment circulating EPCs in patients with AIS. Methods: Demographic data, classical vascular risk factors, treatment and National Institutes of Health Stroke Scale data were prospectively collected from 43 consecutive AIS patients (group I), comprising – 30 treated with statins (group Statin(+)) and 13 untreated (group Statin (-)). Risk factor controls (group II) included 22 subjects matched by age, gender, and traditional vascular risk factors. EPCs were measured by flow cytometry – and the populations of circulating stem cells (CD133+), early EPCs (CD133+/VEGFR2+) and ECs CD34-/CD133-/VEGFR2+ cells were analyzed. Results: Patients ages ranged from 54 to 92 years (mean age 75.2 ± 11.3 years). The number of CD34-/CD133-/VEGF-R2+ cells was significantly lower in group I than II (p<0.05). In group Statin(+) neurological deficit on the 1st, 3rd and 7th day was significantly lower in comparison Statin(-) (p<0.05). We observed significantly more frequent “improvement> 50% or complete recovery” and less frequent death in the statin-treated group. The number of early EPCs and ECs was significantly higher in the treated group on the day 3rd (p < 0.05). Conclusions: Statins treatment is likely to have a positive effect on spontaneous CD133+/ VEGFR2+ and CD34-/CD133-/VEGFR2+ cell mobilization triggered by a stroke.

Objective: In acute ischemic stroke, early neurological deterioration (END) may occur in up to one-third of patients. However, there is still no satisfying or comprehensive predictive model for all the stroke subtypes. We propose a practical model to predict END using magnetic resonance imaging (MRI). Method: Patients with anterior circulation infarct were recruited and they underwent an MRI within 24 hours of stroke onset. END was defined as an elevation of ≥2 points on the National Institute of Health Stroke Scale (NIHSS) within 72 hours of stroke onset. We examined the relationships of END to individual END models, including: A, infarct swelling; B, small subcortical infarct; C, mismatch; and D, recurrence. Results: There were 163 patients recruited and 43 (26.4%) of them had END. The END models A, B and C significantly predicted END respectively after adjusting for confounding factors (p=0.022, p=0.007 and p<0.001 respectively). In END model D, we examined all imaging predictors of Recurrence Risk Estimator (RRE) individually and only the “multiple acute infarcts” pattern was significantly associated with END (p=0.032). When applying END models A, B, C and D, they successfully predicted END (p<0.001; odds ratio: 17.5[95% confidence interval: 5.1– 60.8]), with 93.0% sensitivity, 60.0% specificity, 45.5% positive predictive value and 96.0% negative predictive value. Conclusion: The results demonstrate that the proposed model could predict END in all stroke subtypes of anterior circulation infarction. It provides a practical model for clinical physicians to select high-risk patients for more aggressive treatment to prevent END.

Background: Kinins are pro-inflammatory peptides that mediate numerous vascular and pain responses in tissue injury. Kinins exert their biological functions via two G-protein-coupled receptors: Bradykinin 1 Receptor (B1R) and Bradykinin 2 Receptor (B2R). We previously demonstrated the up-regulation of B2R after Hypoxia/Reoxygenation (H/R) injury in primary cultured cortical neurons. However, the role of B2R in inflammasome-induced pyroptosis remains unknown. Methods: We induced H/R neuronal injury in primary cultured cortical neurons harvested from embryonic day 17 brains. Next, we examined the neuroprotective function of B2R in H/R-induced neuronal apoptosis or necrosis using an annexin V FITC/Propidium Iodide (PI) double-staining technique. The pyroptosis signaling cascade, including caspase-1, IL-1β and IL-18 levels and Cleaved Gasdermin D (GSDMD) expression was examined by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and western blotting to explore the underlying molecular mechanism. Results: H/R injury significantly increased B2R protein expression (P<0.05) as well as the percentage of early apoptotic and necrotic or late apoptotic neurons as verified by the annexin V FITC/PI flow cytometric analysis. Bradykinin (BK), a specific B2R agonist, caused a significant decrease in apoptotic neuronal death after H/R injury, while HOE140, a specific B2R antagonist, markedly reduced the neuroprotective effect of B2R. Following H/R injury, BK downregulated the caspase-1, IL-1β and IL-18 levels (P<0.01). In contrast, pretreatment with HOE140 significantly increased caspase-1, IL-1β, and IL-18 levels (P<0.01). Further analysis revealed that GSDMD, a key executioner of pyroptosis, is a target for B2R-mediated inhibition of neuronal pyroptosis. Cleaved GSDMD expression was significantly inhibited by BK pretreatment and significantly enhanced by HOE140 pretreatment (P<0.01). Conclusion: These results indicate that activation of B2R plays an important role in pyroptosis mediated by H/R injury.

Objective: In this study, we aimed to evaluate the safety and efficiency of low dose intra- arterial tirofiban in mechanical thrombectomy of acute ischemic stroke patients to facilitate the reperfusion of distal vessel. Methods: We retrospectively analyzed 54 consecutive acute ischemic patients who underwent mechanical thrombectomy for large-vessel occlusion. Patients were divided into two groups based on whether intra-arterial tirofiban was used during mechanical thrombectomy to facilitate the reperfusion of distal vessel. Patients in Non-tirofiban group (n=28) have received mechanical thrombectomy, while Patients in Tirofiban group (n=26) have received mechanical thrombectomy with a low dose intra-arterial tirofiban. We comparatively analyzed two groups of the bleeding complications, recanalization rate, 24-hour National Institutes of Health Stroke Scale score, functional independence of 90 day and mortality rate. Results: Of 54 patients undergoing mechanical thrombectomy, baseline characteristics did not differ between the Tirofiban group and Non-tirofiban cohort. Symptomatic intracranial hemorrhage rates were not different between Tirofiban group and Non-tirofiban group (11.5 % vs. 14.3%). Total 47 (87.0%) patients have realized successful recanalization, no apparent difference between two groups (85.7% vs. 88.5%, P>0.05). Mean 24-hour National Institutes of Health Stroke Scale score was 9.24±6.85, 9.11±8.13 in the Non-tirofiban group and 9.39±5.31 in the Tirofiban group respectively, P>0.05. Total 20 (35.7%) patients have achieved functional independence (34.6% vs. 39.3%, P>0.05) at 90 days. Patients treated with tirofiban presented lower mortality when compared with those who were not treated with tirofiban without significant difference (10.7% versus 3.8%, P>0.05). Conclusion: Intra-arterial tirofiban may be safe in mechanical thrombectomy of acute ischemic stroke to facilitate the reperfusion of distal vessel, but has no beneficial effect on prognosis.

Background and Aims: It is unclear whether white blood cell on admission has a prognosis value on ischemic stroke and whether its function is affected by other inflammation factors. We hypothesized that elevated white blood cell is associated with stroke severity and 3-month mortality after acute ischemic stroke. Methods: A total of 3891 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 quartiles of white blood cell on admission (cutoff points for the quintiles: 5.600⁹/L,6.830⁹/L,8.500⁹/L). The primary outcome was a combination of death and major disability (modified Rankin Scale score ≥3) at 3 months. Secondary outcomes were major disability, death, and vascular events, respectively. Results: After adjustment for major conventional risk factors, elevated white blood cell on admission was associated with poor primary and secondary outcomes after acute ischemic stroke. Compared with the lowest quartile, the ORs (95% CIs) for the highest quartile were 1.79 (1.37-2.91) and 1.62 (1.21-3.55) for primary outcome in model 1 and model 2. In addition, there was a linear association between white blood cell and primary outcome at 3-months (P for linear trend = 0.001). Conclusion: This analysis indicated that elevated white blood cell on admission is associated with 3-months poor prognosis in ischemic stroke patients independently of other inflammation factors. The results emphasize the need for further research on the application of anti-inflammatory therapy.

Background: The impact of Total Bile Acids (TBA) level on clinical outcomes after acute Intracerebral Hemorrhage (ICH) is still not understood. Objective: We investigated whether admission TBA level is associated with hematoma volume, stroke clinical severity, and 3-month outcomes in acute ICH patients. Methods: A total of 335 ICH patients were prospectively enrolled. Patients were divided into four groups, according to the quartiles of serum TBA level at the time of admission. Three-month outcomes were evaluated by interviews with patients or their family members. Results: The median hematoma volumes for the quartiles of TBA level (Q1 to Q4) were 12.0, 12.3, 10.0, and 6.7 mL (P<0.001) and the median National Institutes of Health Stroke Scale (NIHSS) scores were 8, 8, 6, and 5 (P=0.002), respectively. In the adjusted models, patients in the highest quartile (Q4) had smaller hematoma volumes (P=0.039) and lower NIHSS scores (P=0.037) than patients in Q1. At three months follow-up, there were 136 patients with poor outcomes (defined as having modified Rankin Scale scores≥3) and 46 cases of all-cause deaths. TBA level was not significantly associated with poor outcome nor all-cause death after adjusting for age, sex, hematoma volume, and baseline NIHSS(all P-trend≥0.380). Conclusions: Higher admission TBA was associated with smaller hematoma volume and decreased clinical severity, but not three month outcomes in patients with acute ICH.

Objective: Idiopathic Intracranial Hypertension (IIH) is a condition of unknown etiology frequently associated with dural sinus stenosis. There is emerging evidence that venous sinus stenting is an effective treatment. We use phase contrast cine MRI to observe changes in flow dynamics of multiple intracranial fluids and their response to different treatments in a patient with IIH. Methods: We quantified the following parameters at the level of the aqueduct of Sylvius and the cervical C2C3: Cerebrospinal Fluid (CSF), arterial and venous flow; CSF velocity amplitude; artero-venous delay (AVD); artero-CSF delay and percentage of venous outflow normalized to total arterial inflow (tIJV/tA). Analyses were run before Lumbar Puncture (LP) (A), after LP (B), after medical therapy (C) and after venous stent placements deployed at two separate times (D and E). Results: AVD and tIJV/tA improved only after CSF removal and after stent placements. CSF velocity amplitude remained elevated. Arterial flow profile showed a dramatic reduction after LP with improvement in mean venous flow. This report is the first to demonstrate interactive changes in intracranial fluid dynamics that occur before and after different therapeutic interventions in IIH. Conclusion: The data provide valuable information regarding changes in different fluid compartments suggesting a profound redistribution of pressures along fluid compartments after different treatments. We discuss how increased intracranial venous blood could be “tumoral” in IIH and facilitating its outflow could be therapeutic.