Current Neurovascular Research - Volume 13, Issue 2, 2016

Brain angiotensin-(1-7) (Ang-(1-7)) concentration has been shown to be reduced and inversely correlated with tau pathology in a mouse model of Alzheimer’s disease (AD). In this study, to determine whether the concentration of Ang-(1-7) and the activity of its converting enzyme angiotensin-converting enzyme 2 were altered in plasma under AD context, the plasma samples from 110 AD patients and 128 age- and gender-matched controls were screened. In AD patients, the plasma concentration of Ang-(1-7) was significantly reduced (15.63±4.35pg/mL vs. 19.58±3.22pg/mL, P<0.001) and positively correlated with cognitive functions (R=0.66, P<0.001). Meanwhile, receiver-operating characteristic analysis showed that the Ang-(1-7) concentration in plasma could distinguish AD patients from controls with the sensitivity and specificity of 69.1% and 74.2%, respectively, when the optimal cut-off value (18.2 pg/mL) was chosen. These findings indicate that plasma Ang-(1-7) may represent a potential biomarker for AD diagnosis, and further suggest an involvement of this heptapeptide in the pathogenesis of this disease.

This study was to determine the clinical diagnostic value of D-dimer for DVT in patients with ischemic stroke. During July 2013 to December 2014, a cohort study of ischemic stroke patients who presented with symptoms of DVT in upper or lower extremities was performed, with a total of 255 patients at baseline. D-dimer levels were measured from each patient using Colour Doppler Ultrasonography (CDUS), and all patients underwent venous duplex examinations. In ours study, 56 patients were diagnosed as DVT (22.0%). When compared to the patients without-DVT, a significantly increased trend of plasma D-dimer levels was found in stroke patients with DVT [3.07 (IQR, 2.26-4.05)mg/L VS. 0.54 (IQR, 0.27-1.14) mg/L; P<0.0001]. From the analysis results of the ROC curve, optimal cutoff value was 1.51 mg/L for diagnosing of DVT (sensitivity: 91.1 %; specificity: 85.4%; the AUC: 0.914 [95%CI, 0.878—0.950; P<0.001]). If cut-off value of 0.5 mg/L, the diagnosis sensitivity was 100%, the specificity was 46.2%, and the positive predictive value was 34.3%. In addition, 36.1% (92/255) stroke patients who suspected with DVT did not need perform CDUS, and those patients could be excluded by plasma D-dimer tested. Collectively, plasma D-dimer level may have a guiding meaning for diagnosing DVT in ischemic stroke patients, and the D-dimer assay is a reliable method for ruling out DVT.

This study was designed to investigate the effects of treatment with the antioxidants N-acetylcysteine (NAC) and deferoxamine (DFX) in intracellular pathways in the brain of diabetic rats. To conduct this study we induced diabetes in Wistar rats with a single injection of alloxan, and afterwards rats were treated with NAC or DFX for 14 days. Following treatment completion, the immunocontent of c-Jun N-terminal kinase (JNK), mitogen-activated protein kinase-38 (MAPK38), brain-derived neurotrophic factor (BDNF), and protein kinases A and C (PKA and PKC) were determined in the prefrontal cortex (PFC), hippocampus, amygdala and nucleus accumbens (NAc). DFX treatment increased JNK content in the PFC and NAc of diabetic rats. In the amygdala, JNK was increased in diabetics treated with saline or NAC. MAPK38 was decreased in the PFC of control and in diabetic rats treated with NAC or DFX; and in the NAc in all groups. PKA was decreased in the PFC with DFX treatment. In the amygdala, PKA content was increased in diabetic rats treated with either saline or NAC, compared to controls; and it was decreased in either NAC or DFX-treated groups, compared to saline-treated diabetic animals. In the NAc, PKA was increased in NAC-treated diabetic rats. PKC was increased in the amygdala of NAC-treated diabetic rats. In the PFC, the BDNF levels were decreased following treatment with DFX in diabetic rats. In the hippocampus of diabetic rats the BDNF levels were decreased. However, treatment with DFX reversed this effect. In the amygdala the BDNF increased with DFX in non-diabetic rats. In the NAc DFX treatment increased the BDNF levels in diabetic rats. In conclusion, both diabetes and treatment with antioxidants were able to alter intracellular pathways involved in the regulation of cell survival in a brain area and treatment-dependent fashion.

Homeobox (HOX) transcript antisense RNA (HOTAIR), as a long intergenic noncoding RNA (lincRNA), is known to be overexpressed in several cancers. However, the role of HOTAIR in Parkinson’s disease (PD) remains unclear. A mouse model of PD was developed by intraperitoneal injection of MPTP (N-methyl-4-phenyl-1,2,3,6- tetrahydropyridine). The expression of HOTAIR and LRRK2 (leucine-rich repeat kinase 2) were detected in the PD mice and in Human neuroblastoma cell lines SH-SY5Y pretreated with MPP+ (N-methyl-4-phenylpyridinium). The effect of HOTAIR on the expression of LRRK2 was examined in SH-SY5Y cells through overexpressing HOTAIR. A MTT (3- (4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assay was performed to measure the cell viability of SH-SY5Y cells. si-HOTAIR (siRNA-HOTAIR) was utilized to investigate the effect of HOTAIR on the expression of LRRK2 in vivo. In this study, upregulation of HOTAIR and LRRK2 were found in the midbrain of PD mice induced by MPTP and in SH-SY5Y cells pretreated with MPP+. With the presence of HOTAIR overexpression in SH-SY5Y cells, the expression of LRRK2 was increased compared with that in the control. HOTAIR knockdown showed a protective effect on the cell viability of SH-SY5Y cells pretreated with MPP+, which was abrogated by overexpression of LRRK2. In mouse model of PD treated with si-HOTAIR, the expression of LRRK2 was decreased. In conclusion, high expression of HOTAIR promoted the onset of PD induced by MPTP. Moreover, the finding that HOTAIR promoted PD induced by MPTP through regulating LRRK2 expression could add our understanding of the molecular mechanisms in PD.

Inflammation is one major cause of poor outcomes of subarachnoid hemorrhage (SAH). The recent evidence suggested that adoptive regulatory T-cell (Treg) therapy conferred potential neuroprotection by suppressing cerebral inflammation against cerebral ischemia. Therefore, we proposed that Treg transfer might protect the brain against SAH by decreasing cerebral inflammation. In this study, we injected the autologous blood into cisterna magna twice to make the SAH model and administrated Tregs by vein to SAH rats. Intriguingly, adoptive transfer of Tregs significantly ameliorated SAH-induced brain edema and increased cerebral blood flow. Moreover, Treg-afforded cerebral protection was accompanied by suppressing SAH-induced cerebral inflammation. Concurrently, administration of Tregs attenuated the activation of the toll-like receptor 4 and nuclear factor-kappa B (TLR4/NF-ΚB) signaling pathway, which should be involved in the suppression of SAH-induced cerebral inflammation. Altogether, our study suggested that Treg adoptive transfer could attenuate SAH-induced cerebral inflammation by suppressing the activation of the TLR4/NF-ΚB signaling pathway, and thus provided new insights into the potent Treg cells-based therapy specifically targeting on post-SAH inflammatory dysregulation.

Pericytes are perivascular cells and have heterogenous roles in the brain, such as controlling blood flow and entry of immune cells or regulating the blood-brain barrier. Platelet-derived growth factor (PDGF) receptor-beta (PDGFRβ) is highly expressed in pericytes, representing the most selective biomarker. The aim of the present study was to culture primary mouse pericytes and to determine the expression pattern by Western Blot as well as immunostainings. We will study the effects of different exogenous stimuli (such as transforming growth factor-β (TGFβ1), PDGF-BB, oxygendeprivation, beta-amyloid or serumfree conditions) on the different pericyte markers. Using Western Blot analyses, we show that PDGFRβ is selectively expressed in pericytes as a 160 kDa protein. Nestin, although not exclusively specific, is also expressed by pericytes, but markedly downregulated under serum-free conditions. PDGF-BB and oxygen-deprivation dramatically reduced PDGFRβ expression, while TGF1 increased its expression. The expression of PDGFRβ was intracellular as shown by confocal microscopy. Using Western Blot analyses, we demonstrate that pericytes also contain a 100 kDa PDGFRβ protein. However, in contrast to cortex brain slices, pericytes do not express a phosphorylated (Y740) isoform. Interestingly, PDGF-BB markedly reduced the 160 kDa isoform of PDGFRβ. In conclusion, our data show a detailed expression of different forms of PDGFRβ in primary pericytes, which is different to brain slices. However, we suggest that PDGFR is a highly selective marker for pericytes.

Hypertension has been reported to induce cognitive decline and dementia of vascular origin. Serotonin- norepinephrine reuptake transporters take part in the control of inflammation, cognitive functions, motivational acts and deterioration of neurons. This study was carried out to examine the effect of venlafaxine; a specific serotonin-norepinephrine reuptake inhibitor (SNRI), in two-kidney-one-clip-2K1C (renovascular hypertension) provoked vascular dementia (VaD) in albino rats. 2K1C technique was performed to provoke renovascular-hypertension in adult male albino Wistar rats. Learning and memory were assessed by using the elevated plus maze and Morris water maze. Mean arterial blood pressure- MABP, as well as endothelial function, were assessed by means of BIOPAC system. Serum nitrosative stress (nitrite/ nitrate), aortic superoxide anion, brain oxidative stress, inflammation, cholinergic dysfunction and brain damage (2,3,5-triphenylterazolium chloride staining) were also assessed. 2K1C has increased MABP, endothelial dysfunction as well as learning and memory impairments. 2K1C method has increased serum nitrosative stress (reduced nitrite/nitrate level), oxidative stress (increased brain thiobarbituric acid reactive species and aortic superoxide anion content along with decreased levels of brain superoxide dismutase, glutathione, and catalase), brain inflammation (increased myeloperoxidase), cholinergic dysfunction (increased acetylcholinesterase activity) and brain damage. Treatment with venlafaxine considerably attenuated renovascular-hypertension induced cognition impairment, endothelial dysfunction, serum nitrosative stress, brain and aortic oxidative stress, cholinergic function, inflammation as well as cerebral damage. The finding of this study indicates that specific modulation of the serotonin-norepinephrine transporter perhaps regarded as potential interventions for the management of renovascular hypertension provoked VaD.

The fiber matrix of the surface glycocalyx layer internally coating the endothelial cells and plugging the intercellular clefts is crucial for microvascular wall homeostasis. Disruption of the glycocalyx is found in clinical conditions characterized by microvascular and endothelial dysfunction such as atherosclerosis, diabetes mellitus, chronic renal failure and cerebrovascular disease. Shedding of its components may also occur during oxidative stress and systemic inflammatory states including septis. In this work, we investigate the effects of glycocalyx degradation, either due to enzymatic digestion or to agonist recruitment, on plasma filtration and solute extravasation. We also take into account the possibility of a physiological or pathological increase in blood pressure, as in hypertensive zones such as pre- and post-stenotic blood vessels. Our mathematical model shows that a seriously damaged glycocalyx produces an augmentation of flux of both solvent and solute, thus losing its role of transport barrier and macro-molecular sieve, in agreement with experimental evidence. Similarly, hypertension causes an increase in both volume and solute fluxes, also according to physiological findings. The combination of glycocalyx deterioration and hypertension further raises plasma and solute fluxes, potentially leading in most severe cases to edema and hemorrhage, as in the case of diabetes.

The existing intracerebral hemorrhage (ICH) scores were based on the clinical and anatomical parameters of all primary ICH. We aimed to study whether the original ICH Score can predict cerebral amyloid angiopathy (CAA)-related ICH mortality and functional outcome and whether modified score can improve the predictions. The patients with ICH were consecutively recruited from 21 tertiary and secondary hospitals across Mainland China from January 2012 to December 2014. CAA-related ICH was defined as Boston Criteria. Logistic regression was performed in the derivation cohort of patients with CAA-related ICH to identify predictors of 3-month mortality and good outcome [modified Rankin score (mRS) of 0-2 at 3 months]. The areas under the receiver operating characteristic curves (AUCs) were used to assess model discrimination. A total of 360 CAA-related ICH patients were included. According to AUCs, the original ICH Score was less reliable predictor for mortality (AUCs=0.69) and good outcome (AUCs=0.67) in CAA- related patients. The range of CAA-related ICH score values is 0 to 7. The scale consist of four clinical items and the score points were assigned based on the Glasgow Coma Scale score on admission, age, presence of intraventricular hemorrhage, and presence of midline shift. CAA-related ICH score showed good discrimination in the derivation cohort (AUCs: 0.87 for mortality; 0.80 for good clinical outcome) and validation cohort (AUCs: 0.89 for mortality; 0.81 for good clinical outcome). The original ICH Score may be less reliable in predicting mortality and good clinical outcome at 3 months for CAA-related ICH patients. The modified scores improve its ability to predict clinical outcome at 3 months for CAA-related ICH.

Depression is the most frequent neuropsychiatric complication after a stroke. Post-stroke depression has a significant impact on the outcome and prognosis of affected patients. Its diagnosis is complex and currently based only on clinical parameters. In recent years, efforts have been made to find biomarkers related to post-stroke outcomes, including complications such as depression. We carried out a systematic review of the literature looking for studies that investigated biomarkers associated with post-stroke depression (PSD) in Medline, Lilacs and PsycInfo databases. The results of 37 studies are discussed, describing the evidence for each evaluated biomarker. In conclusion, no evidence was found supporting the use of a particular biomarker for PSD. However, several changes were observed in inflammatory balance, oxidative stress, glutamatergic neurotransmission, production of neurotrophic factors, and genetic susceptibility that can be related to PSD. Research in the area of post-stroke biomarkers has the potential to provide personalized approach of stroke patients, also aiding in the diagnosis and understanding of the pathophysiology of this common neuropsychiatric complication.