Current Neurovascular Research - Volume 10, Issue 3, 2013

The functions of rapid eye movement (REM) sleep have remained elusive since more than 50 years. Previous reports have identified several independent processes affected by the loss and subsequent recovery of REM sleep (hippocampal neurogenesis, brain stem neuronal cell death, and neurotransmitter content in several brain regions); however, a common underlying mechanism has not been found. We propose that altered brain homeostasis secondary to blood-brain barrier breakdown may explain all those changes induced by REM sleep loss. Therefore, the present report aimed to study the consequences of REM sleep restriction upon blood-brain barrier permeability to Evans blue. REM sleep restriction was induced by the multiple platform technique; male rats were REM sleep restricted 20h daily (with 4h sleep opportunity) during 10 days; control groups included large platform and intact rats. To study blood-brain barrier permeability Evans blue was intracardially administered; stained brains were sliced and photographed for optical density quantification. An independent experiment was carried out to elucidate the mechanism of blood-brain breakdown by transmission electron microscopy. REM sleep restriction increased blood-brain barrier permeability to Evans blue in the whole brain as compared to both control groups. Brief periods of sleep recovery rapidly and effectively restored the severe alteration of blood-brain barrier function by reducing blood-to-brain transfer of Evans blue. The mechanism of bloodbrain barrier breakdown involved increased caveolae formation at brain endothelial cells. In conclusion, our data suggest that REM sleep regulates the physical barrier properties of the blood-brain barrier.

Ischemic stroke causes a significant amount of cell damage resulting from an insufficient supply of glucose and oxygen to central nervous system tissue and finding more effective therapeutic neuroprotective agents has become a priority in the treatment of ischemic stroke. Hsp20, one of the small heat shock proteins, has been implicated in multiple physiological and pathophysiological processes and is a potential neuroprotective agents. To investigate whether Hsp20 exerts protective effects on in vitro ischemia-reperfusion injury, mouse neuroblastoma cells were subjected to oxygenglucose deprivation/reoxygenation (OGDR) insult. The N2a cells transfected with Hsp20 and constitutively phosphorylated Hsp20 (S16D) had significantly less cell loss and less proportion of apoptotic cells compared to N2a cells transfected with pEGFP-N1 after oxygen-glucose deprivation (OGD) 4 h plus 12 and 24 h reperfusion, which showed no difference in N2a cells transfected with nonphosphorylatable Hsp20 (S16A). Meanwhile, transfected with Hsp20 and constitutively phosphorylated Hsp20 (S16D) also significantly attenuated mitochondrial fragmentation and modulated Bcl-2 and Bax expression level after OGD 4 h plus 12 reperfusion, which were not affected in N2a cells transfected with Hsp20 (S16A). In conclusion, our data demonstrated that increased Hsp20 and Hsp20 (S16D) expression in mouse N2A neuroblastoma cells protected against ischemia-reperfusion injury, the neuroprotective mechanism may be related to regulate Bcl-2 and Bax expression. However, blockade of Ser16-Hsp20 phosphorylation attenuated the neuroprotective effects of Hsp20. Therefore, Hsp20 and factors that contribute to regulation of phosphorylation on Ser16 of Hsp20 are potential new therapeutic targets for the treatment of cerebral ischemia-reperfusion injury.

Acupuncture may help motor recovery in chronic stroke survivors, but it is unclear whether it is useful for acute or subacute stroke patients. This study aimed to assess the effiency of electroacupuncture on hemiplegic patients caused by acute first-ever middle cerebral artery infarction. Ninety-eight patients with hemiplegia after first-ever middle cerebral artery infarction were divided into the observation group and the control group. Electroacupuncture was applied once daily for three weeks seven days after symptom onset. The motor functions of the limbs and the activities of daily living (ADL) were evaluated by Fugl–Meyer assessment (FMA) and Barthel index (BI). Serum neuron -specific enolase (NSE), soluble protein-100B (S-100B) and endothelin (ET) were quantified before and after treatment.After treatment, the FMA and BI scores were improved in comparison to before treatment scores in the same group (P<0.01 or P<0.05), with a more significant improvement in the observation group (with electroacupuncture) than in the control group (P<0.01). After treatments, the amounts of serum NSE, S-100B and ET in the observation group were significantly decreased when compared with those of the control group (P<0.01 or P<0.05). No adverse reactions occurred during electroacupuncture. This study showed that motor functions of the limbs and the activities of daily living in hemiplegic patients caused by acute cerebral infarction were improved significantly after treatment with electroacupuncture and this improvement was associated with reduced serum levels of NSE, S-100B and ET.

Mitochondria dynamically change their shape through frequent fusion and fission to continuously perform their function in the cell. Although a change in mitochondrial morphology was reported in amyotrophic lateral sclerosis (ALS), detailed changes of mitochondrial fusion and fission proteins have not been reported in ALS model mice. In transgenic (Tg) mice with the G93A human SOD1 mutation (G93ASOD1), both mitochondrial fusion proteins (Mfn1 and Opal) and fission proteins (Drp1 and Fis1) showed a significant increase in the anterior half of the lumbar spinal cord. Such changes in Tg mice were already noticeable at presymptomatic 10 week (W) compared with wildtype (WT) mice, detected through immunohistochemical as well as Western blot analyses. Furthermore, fusion protein levels of Mfn1 and Opa1 showed a progressive decrease from 10 to 18 W in Tg mice while fission protein levels of P-Drp1 and Fis1 maintained a high level of expression in Tg mice from 10 to 18 W. These data suggest that abnormal changes in mitochondrial morphology began before the onset of ALS and that the balanced mitochondrial morphology becomes altered by fissions in motor neurons (MNs) in this ALS model.

Recent studies suggest that dietary virgin olive oil reduces hypoxia-reoxygenation injury in rat brain. This study investigated the effect of pretreatment with different doses of dietary virgin olive oil on brain lipidomics during stroke. In this experimental trial, 60 male Wistar rats were studied in 5 groups of 12 each. The control group received distilled water while three treatment groups received oral virgin olive oil for 30 days (0.25, 0.5 and 0.75 ml/kg/day respectively). Also the sham group received distilled water. Two hours after the last dose, the animals divided two groups. The middle cerebral artery occlusion (MCAO) group subjected to 60 min of middle cerebral artery occlusion (MCAO) and intact groups for brain lipids analysis. The brain phosphatidylcholine, cholesterol ester and cholesterol levels increased significantly in doses of 0.5 and 0.75 ml/kg/day compare with control group. VOO in all three doses increased the brain triglyceride levels. VOO with dose 0.75 ml/kg increased the brain cerebroside levels when compared with control group. VOO pretreatment for 30 days decreased the brain ceramide levels in doses of 0.5 and 0.75 ml/kg/day (p<0.05). Although further studies are needed, the results indicate that the VOO pretreatment improved the injury of ischemia and reperfusion and might be beneficial in patients with these disorders and seems to partly exert their effects via change in brain lipid levels in rat.

Neurotransmitter assay of epinephrine (EP) was sought using a modified carbon nanotube paste electrode (PE). Using optimum conditions, cyclic voltammetry (CV) and the square wave (SW) stripping voltammetric working ranges were attained to 10-100 mgL-1 (CV) and 20-140 ngL-1 (SW). The relative standard deviation of 0.0549 (n=15) was obtained at 20.0 mgL-1 EP constant. Here, the analytical detection limit (S/N) was reached with 4.60 ngL-1 (2.5×10-11 molL-1) EP. The hand-made electrode was implanted into the in-vivo brain core of the animals and was used in chronoamperometric neuro detection. The results obtained are applicable in neuro sensing, physiological control, and other neuroscience fields.

Oxidative stress is known to contribute to the progression of cerebrovascular disease. Additionally, oxidative stress may be increased by, but also augment inflammation, a key contributor to cerebral aneurysm development and rupture. Oxidative stress can induce important processes leading to cerebral aneurysm formation including direct endothelial injury as well as smooth muscle cell phenotypic switching to an inflammatory phenotype and ultimately apoptosis. Oxidative stress leads to recruitment and invasion of inflammatory cells through upregulation of chemotactic cytokines and adhesion molecules. Matrix metalloproteinases can be activated by free radicals leading to vessel wall remodeling and breakdown. Free radicals mediate lipid peroxidation leading to atherosclerosis and contribute to hemodynamic stress and hypertensive pathology, all integral elements of cerebral aneurysm development. Preliminary studies suggest that therapies targeted at oxidative stress may provide a future beneficial treatment for cerebral aneurysms, but further studies are indicated to define the role of free radicals in cerebral aneurysm formation and rupture. The goal of this review is to assess the role of oxidative stress in cerebral aneurysm pathogenesis.

Alcohol abuse is a major health problem worldwide, resulting to extensive admissions in many general hospitals. The overall economic cost of alcohol abuse is enormous worldwide. As a small molecule, alcohol can easily cross membrane barriers and reach different parts of the body very quickly. Attainment of its equilibrium concentration in different cellular compartments depends on the respective water content. Alcohol can affect several parts of the brain, but, in general, contracts brain tissues, destroys brain cells, as well as depresses the central nervous system. Excessive drinking over a prolonged period of time can cause serious problems with cognition and memory. Alcohol interacts with the brain receptors, interfering with the communication between nerve cells, and suppressing excitatory nerve pathway activity. Neuro-cognitive deficits, neuronal injury, and neurodegeneration are well documented in alcoholics, yet the underlying mechanisms remain elusive. The effect can be both direct and/ or indirect. In this review we highlighted the role of alcoholism on the CNS and its impact on human health.

As an incomplete renal replacement for the patients with either acute or chronic renal failure, membrane-based hemodialysis therapy is progressing rapidly. However, the mortality and morbidity remain unacceptably high. Much effort has been put into improving the biocompatibility of the hemodialysis membranes. To effectively remove small solutes and 'middle molecules' in compact cartridges, the hydraulic and permselective properties of the hemodialysis membranes have also been deeply investigated. An overview of recent progress of different kinds of hemodialysis membranes and their preparation technology, as well as their modification techniques, is presented. The advantages and deficiencies of many synthetic membranes, including cellulose, cellulose acetate (CA), chitosan (CS), polysulfone (PS), poly(ether sulfone) (PES), polyacrylonitrile (PAN), ethylene-vinyl alcohol copolymer (EVOH), poly (methyl methacrylate) (PMMA) and poly(vinyl alcohol) (PVA), etc. are elaborated upon.

Accumulating evidence within the last two decades indicates the association between cardiovascular disease (CVD) and chronic inflammatory state. Under normal conditions fibrin clots are gradually degraded by the fibrinolytic enzyme system, so no permanent insoluble deposits remain in the circulation. However, fibrinolytic therapy in coronary and cerebral thrombosis is ineffective unless it is installed within 3-5 hours of the onset. We have shown that trivalent iron (FeIII) initiates a hydroxyl radical-catalyzed conversion of fibrinogen into a fibrin-like polymer (parafibrin) that is remarkably resistant to the proteolytic dissolution and thus promotes its intravascular deposition. Here we suggest that the persistent presence of proteolysis-resistant fibrin clots causes chronic inflammation. We study the effects of certain amphiphilic substances on the iron- and thrombin-induced fibrinogen polymerization visualized using scanning electron microscopy. We argue that the culprit is an excessive accumulation of free iron in blood, known to be associated with CVD. The only way to prevent iron overload is by supplementation with iron chelating agents. However, administration of free radical scavengers as effective protection against persistent presence of fibrin-like deposits should also be investigated to contribute to the prevention of cardiovascular and other degenerative diseases.