Current Neurovascular Research - Volume 11, Issue 4, 2014

Vascular cell injury, whether it occurs in the central nervous system or in other locations throughout the body, represents a significant factor for subsequent disability and death in individuals worldwide. In fact, coronary artery disease remains the leading cause of mortality and can be caused by vessel stenosis, atherosclerosis, embolic disease, or thrombosis. Loss of blood flow to critical areas in the vascular system leads to endothelial cell dysfunction and death. Treatments to avert coronary artery disease and maintain adequate blood flow include the use of antiplatelet agents, angiotensin-converting-enzyme inhibitors, statins, β-blockers as well as re-vascularization techniques that include coronary artery bypass grafting and percutaneous coronary intervention. Other new strategies include the induction of angiogenesis such with trophic factors that include vascular endothelial growth factor and fibroblast growth factor, the use of stem cell therapies, and the use of cytokines such as erythropoietin to directly protect cardiomyocytes and endothelial cells. In the nervous system, approximately 15 million individuals suffer some form of a stroke every year. In addition to cerebral blood vessel occlusion or intra-cerebral hemorrhage as causes of stroke, rupture of intracranial aneurysms with subarachnoid hemorrhage also can lead to ischemic cerebral injury. Intracranial aneurysms can result from genetic origins or be acquired through conditions such as tobacco use, excessive ethanol consumption, and hypertension. Although stroke leads to significant mortality and morbidity, stroke is no longer ranked as the third leading cause of death in the United States. Multiple factors have resulted in the reduction of stroke incidence, now classified as the fourth leading cause of death, that include reduction in tobacco consumption, heightened awareness to seek rapid treatment for stroke, improved care of hypertension, and better management of low-density lipoprotein cholesterol. Treatment with recombinant tissue plasminogen activator in patients suitable for this therapy also has led to a reduction in mortality and morbidity in stroke patients. Several new treatment strategies are under consideration for stroke that also address central nervous system inflammation to include treatment with cytokines and growth factors, progenitor stem cells, metallic ions, and small molecular regulators of hypoxia inducible factor. Improved management of metabolic disorders such as diabetes also have accounted for the reduction in the incidence of stroke. Yet, diabetes continues to remain a significant factor that leads to vascular cell injury. Diabetes mellitus may affect approximately 170-200 million individuals in the world with millions of additional individuals currently undiagnosed. Complications of diabetes and insulin resistance are associated with oxidant stress that can affect both the cerebrovascular and cardiovascular systems as well as other vessels in the body. Diabetes can lead to platelet dysfunction, acute cerebral or coronary injury, and dysfunction in the sympathetic nervous system. Elevated glucose in vascular endothelial cells can result in the increase of antioxidants that involve superoxide-dismutase, catalase, and glutathione peroxidase. This may represent a reparative response by the body to attempt to reverse the effects of oxidant stress injury in the vascular system. Infection and sepsis are additional disorders that can lead to vascular compromise in the body. Coagulation abnormalities occur in sepsis and can lead to diffuse microvascular thrombosis, depleted platelet counts, disseminated intravascular coagulation, and thrombosis in larger vessels. Infection that leads to vascular cell injury may be bacterial, viral, or parasitic in origin. For example, during infection of the parasite Plasmodium falciparum that leads to malaria, parasitized red blood cells can adhere to endothelial cells and produce impaired blood flow, mechanical occlusion, and ischemic tissue in the brain as well as in the cardiovascular system. Impaired perfusion and vessel occlusion can even occur in the vasculature of the retina. Vasoconstriction and direct endothelial cell dysfunction also have been reported that may be mediated through impaired nitric oxide bioavailability and modulation of endothelins. In this issue of Current Neurovascular Research, new work targets several novel mechanisms for the treatment of vascular disease in the body that can significantly impact blood vessel and vascular endothelial function. In the paper by Lin et al., the authors examined a mechanism for the development of sporadic aneurysms in the Chinese Han population as a result of endoglin, a gene that is involved in vascular development and angiogenesis. Endoglin, as a potential biomarker, would be of great interest to follow and potentially prevent intracranial aneurysm rupture, since most individuals have no symptoms until intracranial aneurysms become symptomatic. The investigators illustrate in the population examined that the endoglin D366H variant (rs1800956) may be clinically relevant since it has an increased association with intracranial aneurysms and may contribute to the sporadic risk in the development and progression of intracranial aneurysms. Takagi et al. consider factors that can lead to intracranial hemorrhage during excessive alcohol consumption. In a model of ethanol-induced endothelial damage, they identify metalloproteinase 9 (MMP-9) as a key mediator of cell injury and show that tight junction disruption and loss of transendothelial electrical resistance was a result of MMP-9 activation in the setting of oxidative stress. Endothelial damage during ethanol-induced damage could be blocked by cilostazol, a phosphodiesterase III inhibitor, through cellular pathways that require protein kinase A and decrease MMP-9 activity. In regards to the use of stem cells for regenerative strategies following vascular injury, Banik et al. identify an enriched population of CD45, CD34 and CD117 stem cells in human umbilical cord. The authors advocate that this cell population is a viable primitive stem cell source that may possess high regenerative properties for the development of future vascular repair strategies. The work of Martoncikova et al. is an interesting companion to the Banik study. Martoncikova et al. show in the rostral migratory stream in a rat model that blood vessels may form a scaffold for the migration of neuronal precursors in the brain, illustrating the vital role of the vascular system in the brain during development and potentially during repair processesfollowing injury. Carvalho et al. focus upon the pathways that contibute to vascular injury during Type 2 diabetes and examine the antioxidant defenses as future therapeutic targets that exist in brain vessels and synaptosomes in animal models of experimental diabetes. They identify several cellular pathways of oxidative imbalance and show that manganese superoxide dismutase activity and vitamin E levels increase with a concomitant decrease in aconitase and glutathione reductase activities, glutathione (GSH)/glutathione disulfide (GSSG) ratio, and GSH and malondialdehyde levels in brain vessels and synaptosomes. Interestingly, an age-dependent increase in hydrogen peroxide levels in both diabetic synaptosomes and vessels was also noted. In their meta-analysis, Panato et al. identify biomarkers markers of bacterial and aseptic meningitis, disorders that can directly lead to vascular cell dysfunction and injury. They show that tumor necrosis factor-α and interleukin-1β are accurate markers to differentiate between bacterial and aseptic meningits with significant elevation of these markers in bacterial meningitis but lower levels of these markers in aspetic meningitis. In our review articles for this issue of Current Neurovascular Research, Maiese presents Wnt1 inducible signaling pathway protein 1 (WISP1) as an emerging novel target for a number of therapeutic strategies especially those relevant for vascular and cardiovascular restoration. WISP1 is a target of the wingless pathway Wnt1 that fosters neuronal and vascular development. WISP1 promotes vascular smooth muscle proliferation that may be important for tissue repair during injury. The reparative properties of WISP1 may be driven by the ability of WISP1 to influence stem cell proliferation, migration, and differentiation. Nabavi et al. examine the antioxidant properties of resveratrol, a natural polyphenolic antioxidant, during stroke. They describe the therapeutic potential of this agent for stroke that modulates several pathways including sirtuins, superoxide dismutase 2, glutathione peroxidase, and nuclear factor-erythroid 2-related factor-2 as well as anti-inflammatory mediators. In this issue of Current Neurovascular Research, new insights into vascular disease and endothelial cell survival are brought forward for the exciting development of new clinical entities. Of course, as with any new developments, we must continue to acquire further understanding of the relevant biology critical for the initiation of new therapeutic strategies and clinical care of vascular disease to avoid unwanted outcomes such as unchecked vascular proliferation. In any event, elegant and focused studies on the problem at hand are always warranted as we “turn up the pressure on vascular disease”.

Intracranial aneurysms (IAs) are acquired lesions in the brain and can pose potential risk of rupture leading to subarachnoid hemorrhage. Endoglin plays a pivotal role in the vascular development and disease. Variations of endoglin gene have been shown to be risk factors for IAs in different racial population. In the present study, we investigated the correlation between polymorphism in the endoglin gene with IAs in Chinese Han population. The association of endoglin D366H variant (rs1800956) with sporadic IAs was tested in 313 patients with intracranial aneurysms, and 450 controls. The difference in allelic frequency between patients and control group was evaluated with the chi-square test. The frequency of the GG+CG genotype of rs1800956 was significantly higher in patients with IAs than in controls [22.0% vs 15.3%, P = .018; crude OR(odds ratio), 1.56; 95% CI(confidence interval), 1.08-2.26]. Multivariate analysis showed that rs1800956G conferred a risk to IAs [adjusted OR, 1.56 [95% CI, 1.08-2.26]; P=.019], independent of conventional factors, including age, sex, blood pressure, smoking, and alcohol consumption. The variant rs1800956 of endoglin might raise the risk of sporadic IAs among individuals of Chinese Han ethnicity.

Intracranial hemorrhage (ICH) remains a devastating disease, and heavy alcohol consumption is an underlying risk factor. The aim of this study was to study the mechanism of ethanol-induced endothelial cell damage and to evaluate the protective effect of cilostazol against ethanol-induced damage. We first evaluated transendothelial electrical resistance (TEER) and cell viability of human brain microvascular endothelial cells at the ethanol concentration shown to cause mild-to-moderate intoxication in the clinic. We also assessed the permeability of fluorescein isothiocyanate (FITC)- dextran and the change in tight junction proteins. Furthermore, we studied the potential of cilostazol to protect endothelial cells from ethanol-induced dysfunction. Concentration- and time-dependent effects of ethanol on cell viability and TEER showed that TEER was reduced at each concentration of ethanol tested during exposures of >2 h, but cell viability was not changed. Permeability of FITC-dextran was enhanced, and both tight junction and adherens junction proteins were reduced by 3-h ethanol treatment. The permeability of FITC-dextran was ameliorated by administration of cilostazol in a concentration-dependent manner. The protective effect of cilostazol was obstructed by administration of a protein kinase A inhibitor. Using gelatin zymography, we found that the protective effect of cilostazol was by reducing matrix metalloproteinase 9 (MMP-9) activation, but it had no effect on reactive oxygen spices (ROS). Our results indicate that cilostazol protected endothelial cells against ethanol-induced endothelial dysfunction by inhibiting ROS-mediated activation of MMP-9.

Human umbilical cord blood (hUCB) is a primitive source of stem cells and is being banked worldwide for the purpose of future clinical use. Lineage negative (Lin-ve) stem cells are one of the primitive populations in hUCB which are capable of self-renewal and differentiation into multiple lineages. These cells have not been adequately investigated for their stem cell characteristics. We have analyzed the immunophenotypic expression of CD45, CD34 and CD117 markers on three different cell populations in hUCB viz., mononucleated cells (MNCs), Lineage positive (Lin+ve) and Lin-ve cells. The CD34 and CD117 expression was found to be 60 fold more in the Lin-ve population as compared to MNCs and Lin+ve cells. This expression was further enhanced in CD45+Lin-ve fraction. The CD34+ and CD117+ Lin-ve cells showed 99% positivity for CD45. Our data suggest that CD34+ CD117+ Lin-ve cells are reasonably enriched stem cell population in hUCB which can be clinically used for transplantation and other therapeutic purposes.

New neurons are continuously being added to the olfactory bulb (OB) of adult rodents that are generated in the subventricular zone (SVZ), distant by a few millimeters. Neuronal precursors have to overcome this long distance without the radial-glial migratory scaffold, in contrast to migration mode during embryonic development. The previous model explains migration of precursors from the SVZ through the rostral migratory stream (RMS) to the OB as a movement of neuroblasts along each other, ensheathed by astroglial tubes. Recent results indicate that blood vessels are suitable candidates for neuronal migration guidance in the RMS. These novel findings have changed the former concept accounting for neuronal precursor migration. The aim of our study was to map a pattern of vascularization in the RMS of adult rats and to investigate mutual relations among blood vessels, neuroblasts and astrocytes in this area. Detailed morphological analysis revealed that blood vessels in the RMS are organized in a specific manner. In most of the RMS extent, blood vessels run parallel to the outline of the migratory pathway. Interestingly, the caudal part of the RMS has a unique vasculature organization in which blood vessels create a spiral-like configuration. Chains of neuroblasts enveloped by astrocytes largely align along blood vessels. The exception is the caudal part of the RMS where neuroblasts do not follow non – parallel blood vessels. Our morphological findings suggest that blood vessels and astrocytes may cooperatively form physical substrate - scaffold for the neuroblasts migration in the RMS of adult rats.

Alterations in brain structure and function are a well-known long-term complication of type 2 diabetes (T2D). Although the mechanism(s) by which T2D lead(s) to cognitive dysfunction and neuronal cells degeneration continue(s) to be a matter of debate, vascular alterations emerged as major players in this scenario. This study was aimed to evaluate the antioxidant defenses and oxidative markers present in brain vessels and synaptosomes from 3- and 12-month-old Goto- Kakizaki (GK) rats, a spontaneous non-obese model of T2D, and Wistar control rats. A significant increase in manganese superoxide dismutase (MnSOD) activity and vitamin E levels and a significant decrease in aconitase and glutathione reductase (GR) activities, glutathione (GSH)/glutathione disulfide (GSSG) ratio, and GSH and malondialdehyde (MDA) levels were observed in brain vessels and synaptosomes from GK rats, and these effects were not significantly affected by aging. However, an age-dependent increase in hydrogen peroxide (H2O2) levels in both diabetic synaptosomes and vessels was observed. No significant alterations were observed in the activity of glutathione peroxidase (GPx) and GR in both brain vessels and synaptosomes from diabetic animals. In control rats, an age-dependent increase in the activity of GPx, GR, and MnSOD and vitamin E and MDA levels and an age-dependent decrease in GSH levels were observed in brain vessels. In contrast, a significant age-dependent increase in GSH levels and a decrease in vitamin E levels were observed in synaptosomes from control animals. Altogether, our results show that T2D and aging differently affect brain vessels and synaptosomes. However, both conditions increase the vulnerability of brain structures to degenerative events.

Background: Meningitis is a complex and severe acute infectious disease of the central nervous system and is caused mainly by bacteria and viruses. However, the distinction between aseptic and bacterial meningitis can be difficult for clinicians because the symptoms and the results of laboratory assays are often similar and overlapping, particularly when the use of antibiotics is administered prior to examining the cerebrospinal fluid. Methods: We determined the accuracy of tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) for the differential diagnosis between bacterial and aseptic meningitis. A comprehensive search was performed for papers published from January 1989 to July 2013. Prospective or retrospective studies and cerebrospinal fluid (CSF) TNF-α and/or IL-1β cytokine concentrations for differential diagnosis distinguishing bacterial from aseptic meningitis were included. Results: A statistical analysis was performed using Revman and Meta-Disc. This systematic review showed that TNF-α has a sensitivity of 80.5%, specificity of 94.9%, diagnostic odds ratio (DOR) of 71.7, and area under the curve (AUC) = 0.942; IL-1β showed a sensitivity of 86.0%, specificity of 92.3%, DOR of 53.5, and AUC = 0.975. Conclusion: Therefore, TNF-α and IL-1β are useful markers for the prediction of the bacterial meningitis and levels may represent an accurate method that is useful for the differentiation between bacterial and aseptic meningitis.

We studied cerebrospinal fluid (CSF) flow dynamics at the cervical level in association with internal jugular vein (IJV) flow for 92 patients with multiple sclerosis (MS). Phase contrast magnetic resonance imaging was used to quantify flow of the CSF and major vessels (including the IJV and the carotid arteries) at the C2-C3 level in the neck. Contrast enhanced MR angiography and time-of-flight MR venography were used to subdivide MS patients into stenotic (ST) and non-stenotic (NST) populations. We evaluated: IJV flow normalized by arterial flow; CSF peaks; CSF outflow duration and its onset from systole. We tested if these variables were statistically different among different MS phenotypes and between ST and NST MS patients. The delay between the beginning of systole and the CSF outflow was higher in ST compared to NST MS. Less IJV flow was observed in ST vs NST MS. None of the measures was different between the different MS phenotypes. These results suggest that alterations of IJV morphology affect both IJV flow and CSF flow timing but not CSF flow amplitude.

It is known that cognitive processes, such as learning and memory, are affected in depression. Several authors have described histone deacetylase (HDAC) inhibitors as a class of drugs that improve long-term memory formation. The current study examined the effects of maternal deprivation (MD) and chronic mild stress (CMS), which have been shown as animal models of depression, and the effects of sodium butyrate (SB), a HDAC inhibitor, on recognition memory. Considering that neurotrophic factors have been pointed as a key event involved in cognition and depressive disorder, levels of neurotrophic factors (BDNF, NGF and GDNF) were investigated. MD and CMS induced depressive-like behavior in the forced swimming test (FST) and memory impairment in the object recognition (OR) test, without altering locomotor activity of rats. In addition, SB was able to reverse the stress-induced neurotrophic factors decrease and reversed memory impairment. The results indicate that stress both at early and later stage of life may induce cognitive impairment in animals and neurotrophic factors (BDNF, NGF and GDNF) levels decrease. SB treatment improved the recognition memory and reversed the neurotrophins levels decreased in the hippocampus of rats submitted to the MD and CMS models. Together, our results reinforce the notion that SB displays a specific antidepressant profile and improves cognition in MD and CMS rats that may be, at least in part, due to its upregulation of neurotrophic factors.

Both of gp91phox (an isoform of nicotinamide adenine dinucleotide phosphate reduced oxidases) and Src (a nonreceptor protein tyrosine kinase) are abundantly expressed in the brain and play a prominent role in mediating ischemic alteration in neurons. The inhibitory strategy of them is believed to be the promising treatment of stroke. The present study was designed to investigate the effect of equol (0.625–2.5 mg·kg-1, i.g. for 3 days), a predominant active metabolite of daidzein, on neuroprotection against cerebral ischemia/reperfusion injury in rats and the underlying mechanisms. We found that equol decreased the mortality, neurological deficit, brain histological damage, infarct volume, serum lactate dehydrogenase activity and malondialdehyde content in a dose-dependent manner in rats with 2-h middle cerebral artery occlusion, followed by 22-h reperfusion. Western blot analysis revealed that protein levels of gp91phox and phosphorylated Src-Tyr416 (p-Src) in ischemic cerebral cortex were increased in rats treated with vehicle, which was reversed in animals treated with equol. In rat pheochromocytoma cell line (PC12) with hypoxia/reoxygenation injury, silencing of gp91phox with specific siRNA did not affect the increase of p-Src level by hypoxia/reoxygenation injury and the inhibition of p-Src level by equol, while silencing of Src suppressed the upregulation of gp91phox by hypoxia/reoxygenation injury and enhanced the inhibitory effect of equol on gp91phox expression. These results demonstrate that equol confers a neuroprotection in rats via inhibiting the activation of Src and upregulation of gp91phox induced by focal cerebral ischemia/reperfusion, and Src may play a partial role in regulating gp91phox expression of neurons.

As a proliferative and restorative entity, Wnt1 inducible signaling pathway protein 1 (WISP1) is emerging as a novel target for a number of therapeutic strategies that are relevant for disorders such as traumatic injury, neurodegeneration, musculoskeletal disorders, cardiovascular disease, pulmonary compromise, and control of tumor growth as well as distant metastases. WISP1, a target of the wingless pathway Wnt1, oversees cellular mechanisms that include apoptosis, autophagy, cellular migration, stem cell proliferation, angiogenesis, immune cell modulation, and tumorigenesis. The signal transduction pathways of WISP1 are broad and involve phosphoinositide 3-kinase (PI 3-K), protein kinase B (Akt), mitogen activated protein (MAP) kinase, c-Jun N-terminal kinase (JNK), caspases, forkhead transcription factors, sirtuins, c-myc, glycogen synthase kinase -3β (GSK-3β), β-catenin, miRNAs, and the mechanistic target of rapamaycin (mTOR). Ultimately, these signal transduction pathways of WISP1 can result in varied and sometimes unpredictable outcomes especially for cell survival, tissue repair, and tumorigenesis that demand increased insight into the critical role WISP1 holds for cellular biology and clinical medicine.

Stroke is one of the most common cardiovascular diseases and is known as a leading cause of death in the world. Despite to its high prevalence, there are limited effective therapeutic strategies for stroke till now. However, oxidative stress plays an important role in the pathogenesis of stroke and therefore, antioxidant therapy could be used as a new therapeutic strategy. Among the antioxidants, some natural compounds are very interesting due to their low adverse effects. Resveratrol (3, 5, 4’-trihydroxystilbene) is a natural polyphenolic antioxidant found in grape skin, grape products, and peanuts as well as in red wine. In recent years, much attention has been paid to resveratrol due to its wide range of antioxidant actions. Resveratrol possesses cardioprotective actions through stimulation of nitric oxide production as well as antioxidative and anti-inflammatory effects. Here we review the available literatures on beneficial role of resveratrol on ischemic stroke. We also provide information about chemistry, sources, bioavailability, as well as clinical impacts of resveratrol.