RESUMO
BACKGROUND AND PURPOSE: Oxidative stress is an early response to cerebral ischemia and is likely to play an important role in the pathogenesis of cerebral ischemic injury. We sought to evaluate whether hyperacute plasma concentrations of biomarkers of oxidative stress, inflammation, and tissue damage predict infarct growth (IG). METHODS: We prospectively measured plasma F2-isoprostane (F2-isoP), urinary 8-oxo-7,8-dihydro-2'-deoxyguoanosine, plasma oxygen radical absorbance capacity assay, high sensitivity C reactive protein, and matrix metalloproteinase 2 and 9 in consecutive patients with acute ischemic stroke presenting within 9 hours of symptom onset. Patients with baseline diffusion-weighted magnetic resonance imaging and follow-up diffusion-weighted imaging or computed tomographic scan were included to evaluate the final infarct volume. Baseline diffusion-weighted imaging volume and final infarct volume were analyzed using semiautomated volumetric method. IG volume was defined as the difference between final infarct volume and baseline diffusion-weighted imaging volume. RESULTS: A total of 220 acute ischemic stroke subjects were included in the final analysis. One hundred seventy of these had IG. Baseline F2-isoP significantly correlated with IG volume (Spearman ρ=0.20; P=0.005) and final infarct volume (Spearman ρ=0.19; P=0.009). In a multivariate binary logistic regression model, baseline F2-isoP emerged as an independent predictor of the occurrence of IG (odds ratio, 2.57; 95% confidence interval, 1.37-4.83; P=0.007). In a multivariate linear regression model, baseline F2-isoP was independently associated with IG volume (B, 0.38; 95% confidence interval, 0.04-0.72; P=0.03). CONCLUSIONS: Elevated hyperacute plasma F2-isoP concentrations independently predict the occurrence of IG and IG volume in patients with acute ischemic stroke. If validated in future studies, measuring plasma F2-isoP might be helpful in the acute setting to stratify patients with acute ischemic stroke for relative severity of ischemic injury and expected progression.
Assuntos
Infarto Encefálico/sangue , Lesões Encefálicas/sangue , Proteína C-Reativa/metabolismo , F2-Isoprostanos/sangue , Estresse Oxidativo , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Infarto Encefálico/patologia , Lesões Encefálicas/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos ProspectivosRESUMO
Originally identified as an angiogenic factor, vascular endothelial growth factor (VEGF-A) is now known to play multiple roles in the CNS, including the direct regulation of neuronal and astrocytic functions. Here, we ask whether VEGF-A can also have a novel role in white matter by modulating oligodendrocyte precursor cells (OPCs). OPCs were cultured from rat neonatal cortex. Expression of VEGF-receptor2/KDR/Flk-1 was confirmed with Western blot and immunostaining. VEGF-A did not affect proliferation or differentiation in OPC cultures, but VEGF-A promoted OPC migration in a concentration-dependent manner. Consistent with this migration phenotype, VEGF-A-treated OPCs showed reorganization of actin cytoskeleton in leading-edge processes. VEGF-A-induced migration and actin reorganization were inhibited by an anti-Flk-1 receptor-blocking antibody. Mechanistically, VEGF-A induced binding of focal adhesion kinase (FAK) with paxillin. The FAK inhibitor PF573228 reduced VEGF-A-induced OPC migration. VEGF-A signaling also evoked a transient rise in reactive oxygen species (ROS), and OPC migration was increased when antioxidants were removed from the culture media. Our findings demonstrate that VEGF-A can induce OPC migration via an ROS- and FAK-dependent mechanism, and suggest a novel role for VEGF-A in white-matter maintenance and homeostasis.
Assuntos
Movimento Celular/genética , Oligodendroglia/efeitos dos fármacos , Células-Tronco/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/farmacologia , Actinas/metabolismo , Animais , Animais Recém-Nascidos , Antígenos/metabolismo , Antioxidantes/farmacologia , Contagem de Células , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Córtex Cerebral/citologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Feminino , Gangliosídeos/metabolismo , Masculino , Oligodendroglia/fisiologia , Paxilina/farmacocinética , Ligação Proteica/efeitos dos fármacos , Proteoglicanas/metabolismo , Quinolonas/farmacologia , Ratos , Ratos Sprague-Dawley , Células-Tronco/fisiologia , Sulfonas/farmacologia , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
After stroke and brain injury, cortical gray matter recovery involves mechanisms of neurovascular matrix remodeling. In white matter, however, the mechanisms of recovery remain unclear. In this study, we demonstrate that oligodendrocytes secrete matrix metalloproteinase-9 (MMP-9), which accelerates the angiogenic response after white matter injury. In primary oligodendrocyte cultures, treatment with the proinflammatory cytokine interleukin-1ß (IL-1ß) induced an upregulation and secretion of MMP-9. Conditioned media from IL-1ß-stimulated oligodendrocytes significantly amplified matrigel tube formation in brain endothelial cells, indicating that MMP-9 from oligodendrocytes can promote angiogenesis in vitro. Next, we asked whether similar signals and substrates operate after white matter injury in vivo. Focal white matter injury and demyelination was induced in mice via stereotactic injection of lysophosphatidylcholine into corpus callosum. Western blot analysis showed that IL-1ß expression was increased in damaged white matter. Immunostaining demonstrated MMP-9 signals in myelin-associated oligodendrocytic basic protein-positive oligodendrocytes. Treatment with an IL-1ß-neutralizing antibody suppressed the MMP-9 response in oligodendrocytes. Finally, we confirmed that the broad spectrum MMP inhibitor GM6001 inhibited angiogenesis around the injury area in this white matter injury model. In gray matter, a neurovascular niche promotes cortical recovery after brain injury. Our study suggests that an analogous oligovascular niche may mediate recovery in white matter.
Assuntos
Lesões Encefálicas/fisiopatologia , Comunicação Celular/fisiologia , Córtex Cerebral/citologia , Endotélio/fisiologia , Oligodendroglia/fisiologia , Animais , Animais Recém-Nascidos , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Lesões Encefálicas/patologia , Comunicação Celular/efeitos dos fármacos , Células Cultivadas , Meios de Cultivo Condicionados/farmacologia , Dipeptídeos/farmacologia , Modelos Animais de Doenças , Endotélio/efeitos dos fármacos , Técnicas In Vitro , Interleucina-1beta/metabolismo , L-Lactato Desidrogenase/metabolismo , Masculino , Proteína Básica da Mielina/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Fator de Transcrição 2 de Oligodendrócitos , Oligodendroglia/química , Oligodendroglia/efeitos dos fármacos , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Inibidores de Proteases/farmacologia , Ratos , Ratos Sprague-DawleyRESUMO
The cerebral endothelium can be a vital source of signaling factors such as brain-derived neurotrophic factor that defends the neuronal parenchyma against stress and injury. But the underlying mechanisms remain to be fully defined. Here, we use cell models to ask how vascular neuroprotection is sustained. Human brain endothelial cells were grown in culture, and conditioned media were transferred to primary rat cortical neurons. Brain endothelial cell-conditioned media activated neuronal Akt signaling and protected neurons against hypoxia and oxygen-glucose deprivation. Blockade of Akt phosphorylation with the PI3-kinase inhibitor LY294002 negated this vascular neuroprotective effect. Upstream of Akt signaling, the brain-derived neurotrophic factor receptor TrkB (neurotrophic tyrosine kinase receptor, type 2) was involved because depletion with TrkB/Fc eliminated the ability of endothelial-conditioned media to protect neurons against hypoxia. Downstream of Akt signaling, activation of GSK-3ß (glycogen synthase kinase 3 beta), caspase 9, caspase 3 and Bad pathways were detected. Taken together, these findings suggest that the molecular basis for vascular neuroprotection involves TrkB-Akt signaling that ameliorates neuronal apoptosis. Further investigation of these mechanisms may reveal new approaches for augmenting endogenous vascular neuroprotection in stroke, brain injury, and neurodegeneration.
Assuntos
Hipóxia Celular/efeitos dos fármacos , Meios de Cultivo Condicionados/farmacologia , Fármacos Neuroprotetores/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptor trkB/metabolismo , Transdução de Sinais/efeitos dos fármacos , Análise de Variância , Animais , Hipóxia Celular/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Córtex Cerebral/citologia , Cromonas/farmacologia , Embrião de Mamíferos , Células Endoteliais/química , Inibidores Enzimáticos/farmacologia , Glucose/deficiência , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Humanos , Hipóxia/tratamento farmacológico , Hipóxia/metabolismo , Microvasos/citologia , Morfolinas/farmacologia , Neurônios , Fosforilação/efeitos dos fármacos , RatosRESUMO
Phosphodiesterase 5A (PDE5A) inhibitors improve functional recovery after middle cerebral artery occlusion (MCA-o) in rats. We used the PDE5A inhibitor 3-(4-(2-hydroxyethyl)piperazin-1-yl)-7-(6-methoxypyridin-3-yl)-1-(2-propoxyethyl)pyrido[3,4-b]pyrazin-2(1H)-one hydrochloride (PF-5) to determine the timing, duration, and degree of inhibition that yields maximum efficacy. We also investigated the localization of PDE5A to determine the tissues and cells that would be targets for PDE5 inhibition and that may mediate efficacy. Nearly complete inhibition of PDE5A, starting 24 h after MCA-o and continued for 7 days, resulted in nearly complete recovery of sensorimotor function that was sustained for 3 months. Delaying administration until 72 h after MCA-o resulted in equivalent efficacy, whereas delaying treatment for 14 days was ineffective. Treatment for 7 days was equivalently efficacious to 28 or 84 days of treatment, whereas treatment for 1 day was less effective. In the normal forebrain, PDE5A immunoreactivity was prominent in smooth muscle of meningeal arteries and a few smaller blood vessels, with weak staining in a few widely scattered cortical neurons and glia. At 24 and 48 h after MCA-o, the number and intensity of blood vessel staining increased in the infarcted cortex and striatum. PDE5A immunoreactivity also was increased at 48 h in putative microglia in penumbra, whereas there was no change in staining of the scattered cortical neurons. Given the window for efficacy and the PDE5A distribution, we hypothesize that efficacy results from an effect on vasculature, and perhaps modulation of microglial function, both of which may facilitate recovery of neuronal function.
Assuntos
Encéfalo/efeitos dos fármacos , Inibidores da Fosfodiesterase 5 , Inibidores de Fosfodiesterase/administração & dosagem , Inibidores de Fosfodiesterase/uso terapêutico , Acidente Vascular Cerebral/tratamento farmacológico , Animais , Comportamento Animal/efeitos dos fármacos , Encéfalo/irrigação sanguínea , Encéfalo/enzimologia , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5/biossíntese , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Esquema de Medicação , Masculino , Microglia/efeitos dos fármacos , Microglia/enzimologia , Atividade Motora/efeitos dos fármacos , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/enzimologia , Inibidores de Fosfodiesterase/farmacologia , Ratos , Ratos Sprague-Dawley , Acidente Vascular Cerebral/enzimologia , Acidente Vascular Cerebral/fisiopatologia , Fatores de TempoRESUMO
Angiotensin-II (Ang-II) is a key factor in hypertension, diabetes and aging, which are all primary risk factors for CNS disease. Furthermore, Ang-II may play under-appreciated roles in neurogenesis, angiogenesis and CNS remodeling. Therefore, any contemplated attempts for neurorestorative therapies in the CNS should consider the context of Ang-II signaling. Here, we investigate how Ang-II may regulate cerebral endothelial permeability, a key functional feature of the neurovascular unit. Exposure of human brain endothelial cell cultures to Ang-II increased its permeability to BSA-Alexa488 tracer. Immunocytochemistry and pulse-chase experiments suggested that both para-cellular as well as trans-cellular pathways were involved. Candesartan but not PD123319 blocked Ang-II permeability effects, suggesting that Ang-II effects may be mediated via type 1 receptor. Immunocytochemistry and western blots showed that Ang-II disrupted the membrane distributions of ZO-1 and VE-Cad, decreased total levels of JAM-A and Mfsd2a, and increased Cav1. These effects of Ang-II were accompanied by dephosphorylation of PPARalpha. Finally, Ang-II-induced increases in endothelial permeability were ameliorated by PPARalpha agonists. Taken together, these studies suggest that Ang-II may disrupt both para- and trans-cellular permeability in cerebral endothelium, and PPARalpha-related pathways may offer potential therapeutic targets for ameliorating these effects in cell-based regenerative medicine.
Assuntos
Angiotensina II/metabolismo , Encéfalo/metabolismo , Permeabilidade Capilar , Células Endoteliais/metabolismo , PPAR alfa/metabolismo , Angiotensina II/administração & dosagem , Encéfalo/efeitos dos fármacos , Permeabilidade Capilar/efeitos dos fármacos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Células Cultivadas , Células Endoteliais/efeitos dos fármacos , Humanos , Transdução de SinaisRESUMO
OBJECTIVES: To assess whether plasma biomarkers of oxidative stress predict diffusion-perfusion mismatch in patients with acute ischemic stroke (AIS). METHODS: We measured plasma levels of oxidative stress biomarkers such as F2-isoprostanes (F2-isoPs), total and perchloric acid Oxygen Radical Absorbance Capacity (ORACTOT and ORACPCA), urinary levels of 8-oxo-7,8-dihydro-2'-deoxyguoanosine, and inflammatory and tissue-damage biomarkers (high-sensitivity C-reactive protein, matrix metalloproteinase-2 and -9) in a prospective study of patients with AIS presenting within 9 hours of symptom onset. Diffusion-weighted (DWI) and perfusion-weighted (PWI) MRI sequences were analyzed with a semiautomated volumetric method. Mismatch was defined as baseline mean transit time volume minus DWI volume. A percent mismatch cutoff of >20% was considered clinically significant. A stricter definition of mismatch was also used. Mismatch salvage was the region free of overlap by final infarction. RESULTS: Mismatch >20% was present in 153 of 216 (70.8%) patients (mean [±SD] age 69.2 ± 14.3 years, 41.2% women). Patients with mismatch >20% were more likely to have higher baseline plasma levels of ORACPCA (p = 0.020) and F2-isoPs (p = 0.145). Multivariate binary logistic regression demonstrated that lnF2-isoP (odds ratio [OR] 2.44, 95% confidence interval [CI] 1.19-4.98, p = 0.014) and lnORACPCA (OR 4.18, 95% CI 1.41-12.41, p = 0.010) were independent predictors of >20% PWI-DWI mismatch and the stricter mismatch definition, respectively. lnORACTOT significantly predicted mismatch salvage volume (>20% mismatch p = 0.010, stricter mismatch definition p = 0.003). CONCLUSIONS: Elevated hyperacute plasma levels of F2-isoP and ORAC are associated with radiographic evidence of mismatch and mismatch salvage in patients with AIS. If validated, these findings may add to our understanding of the role of oxidative stress in cerebral tissue fate during acute ischemia.
Assuntos
Biomarcadores/análise , Isquemia Encefálica/metabolismo , Estresse Oxidativo/fisiologia , Acidente Vascular Cerebral/metabolismo , Adulto , Idoso , Isquemia Encefálica/diagnóstico , Isquemia Encefálica/fisiopatologia , Circulação Cerebrovascular/fisiologia , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Isquemia/metabolismo , Isquemia/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/fisiopatologiaRESUMO
Perturbations in blood vessels play a critical role in the pathophysiology of brain injury and neurodegeneration. Here, we use a systematic genome-wide transcriptome screening approach to investigate the vasculome after brain trauma in mice. Mice were subjected to controlled cortical impact and brains were extracted for analysis at 24 h post-injury. The core of the traumatic lesion was removed and then cortical microvesels were isolated from nondirectly damaged ipsilateral cortex. Compared to contralateral cortex and normal cortex from sham-operated mice, we identified a wide spectrum of responses in the vasculome after trauma. Up-regulated pathways included those involved in regulation of inflammation and extracellular matrix processes. Decreased pathways included those involved in regulation of metabolism, mitochondrial function, and transport systems. These findings suggest that microvascular perturbations can be widespread and not necessarily localized to core areas of direct injury per se and may further provide a broader gene network context for existing knowledge regarding inflammation, metabolism, and blood-brain barrier alterations after brain trauma. Further efforts are warranted to map the vasculome with higher spatial and temporal resolution from acute to delayed phase post-trauma. Investigating the widespread network responses in the vasculome may reveal potential mechanisms, therapeutic targets, and biomarkers for traumatic brain injury.
Assuntos
Lesões Encefálicas Traumáticas , Encéfalo/irrigação sanguínea , Córtex Cerebral/lesões , Microvasos , Transcriptoma , Animais , Encéfalo/imunologia , Encéfalo/metabolismo , Lesões Encefálicas Traumáticas/imunologia , Lesões Encefálicas Traumáticas/metabolismo , Lesões Encefálicas Traumáticas/patologia , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microvasos/imunologia , Microvasos/metabolismoRESUMO
A free radical scavenger edaravone is clinically used in Japan for acute stroke, and several basic researches have carefully examined the mechanisms of edaravone's protective effects. However, its actions on pro-inflammatory responses under stroke are still understudied. In this study, we subjected adult male Sprague-Dawley rats to 90-min middle cerebral artery (MCA) occlusion followed by reperfusion. Edaravone was treated twice via tail vein; after MCA occlusion and after reperfusion. As expected, edaravone-treated group showed less infarct volume and edema formation compared with control group at 24-h after an ischemic onset. Furthermore, edaravone reduced the levels of plasma interleukin (IL)-1ß and matrix metalloproteinase-9 at 3-h after ischemic onset. Several molecules besides IL-1ß and MMP-9 are involved in inflammatory responses under stroke conditions. Therefore, we also examined whether edaravone treatment could decrease a wide range of pro-inflammatory cytokines/chemokines by testing rat plasma samples with a rat cytokine array. MCAO rats showed elevations in plasma levels of CINC-1, Fractalkine, IL-1α, IL-1ra, IL-6, IL-10, IP-10, MIG, MIP-1α, and MIP-3α, and all these increases were reduced by edaravone treatment. These data suggest that free radical scavengers may reduce systemic inflammatory responses under acute stroke conditions, and therefore, oxidative stress can be still a viable target for acute stroke therapy.
Assuntos
Antipirina/análogos & derivados , Citocinas/sangue , Sequestradores de Radicais Livres/uso terapêutico , Ataque Isquêmico Transitório/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Animais , Antipirina/uso terapêutico , Edema Encefálico/tratamento farmacológico , Infarto Cerebral/tratamento farmacológico , Infarto Cerebral/patologia , Edaravone , Inflamação/tratamento farmacológico , Interleucina-1beta/sangue , Ataque Isquêmico Transitório/metabolismo , Ataque Isquêmico Transitório/patologia , Masculino , Metaloproteinase 9 da Matriz/sangue , Ratos Sprague-Dawley , Regulação para CimaRESUMO
Aging and vascular comorbidities such as hypertension comprise critical cofactors that influence how the brain responds to stroke. Ischemic stress induces neurogenesis and oligodendrogenesis in younger brains. However, it remains unclear whether these compensatory mechanisms can be maintained even under pathologically hypertensive and aged states. To clarify the age-related remodeling capacity after stroke under hypertensive conditions, we assessed infarct volume, behavioral outcomes, and surrogate markers of neurogenesis and oligodendrogenesis in acute and subacute phases after transient focal cerebral ischemia in 3- and 12-month-old spontaneously hypertensive rats (SHRs). Hematoxylin and eosin staining showed that 3- and 12-month-old SHRs exhibited similar infarction volumes at both 3 and 14 days after focal cerebral ischemia. However, recovery of behavioral deficits (neurological score assessment and adhesive removal test) was significantly less in 12-month-old SHRs compared to 3-month-old SHRs. Concomitantly, numbers of nestin(+) neural stem/progenitor cells (NSPCs) near the infarct border area or subventricular zone in 12-month-old SHRs were lower than 3-month-old SHRs at day 3. Similarly, numbers of PDGFR-α(+) oligodendrocyte precursor cells (OPCs) in the corpus callosum were lower in 12-month-old SHRs at day 3. Lower levels of NSPC and OPC numbers were accompanied by lower expression levels of phosphorylated CREB. By day 14 postischemia, NSPC and OPC numbers in 12-month-old SHRs recovered to similar levels as in 3-month-old SHRs, but the numbers of proliferating NSPCs (Ki-67(+)nestin(+) cells) and proliferating OPCs (Ki-67(+)PDGFR-α(+) cells) remained lower in the older brains even at day 14. Taken together, these findings suggest that aging may also decrease poststroke compensatory responses for neurogenesis and oligodendrogenesis even under hypertensive conditions.
Assuntos
Envelhecimento/metabolismo , Infarto Encefálico/metabolismo , Células-Tronco Neurais/metabolismo , Neurogênese , Oligodendroglia/metabolismo , Envelhecimento/patologia , Animais , Infarto Encefálico/patologia , Masculino , Células-Tronco Neurais/patologia , Oligodendroglia/patologia , Ratos , Ratos Endogâmicos SHRRESUMO
The blood vessel is no longer viewed as passive plumbing for the brain. Increasingly, experimental and clinical findings suggest that cerebral endothelium may possess endocrine and paracrine properties - actively releasing signals into and receiving signals from the neuronal parenchyma. Hence, metabolically perturbed microvessels may contribute to central nervous system (CNS) injury and disease. Furthermore, cerebral endothelium can serve as sensors and integrators of CNS dysfunction, releasing measurable biomarkers into the circulating bloodstream. Here, we define and analyze the concept of a brain vasculome, i.e. a database of gene expression patterns in cerebral endothelium that can be linked to other databases and systems of CNS mediators and markers. Endothelial cells were purified from mouse brain, heart and kidney glomeruli. Total RNA were extracted and profiled on Affymetrix mouse 430 2.0 micro-arrays. Gene expression analysis confirmed that these brain, heart and glomerular preparations were not contaminated by brain cells (astrocytes, oligodendrocytes, or neurons), cardiomyocytes or kidney tubular cells respectively. Comparison of the vasculome between brain, heart and kidney glomeruli showed that endothelial gene expression patterns were highly organ-dependent. Analysis of the brain vasculome demonstrated that many functionally active networks were present, including cell adhesion, transporter activity, plasma membrane, leukocyte transmigration, Wnt signaling pathways and angiogenesis. Analysis of representative genome-wide-association-studies showed that genes linked with Alzheimer's disease, Parkinson's disease and stroke were detected in the brain vasculome. Finally, comparison of our mouse brain vasculome with representative plasma protein databases demonstrated significant overlap, suggesting that the vasculome may be an important source of circulating signals in blood. Perturbations in cerebral endothelial function may profoundly affect CNS homeostasis. Mapping and dissecting the vasculome of the brain in health and disease may provide a novel database for investigating disease mechanisms, assessing therapeutic targets and exploring new biomarkers for the CNS.
Assuntos
Encéfalo/metabolismo , Células Endoteliais/metabolismo , Transcriptoma , Animais , Proteínas Sanguíneas/metabolismo , Encéfalo/irrigação sanguínea , Doenças do Sistema Nervoso Central/genética , Doenças do Sistema Nervoso Central/metabolismo , Análise por Conglomerados , Bases de Dados de Proteínas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Camundongos , Neovascularização Fisiológica , Ligação Proteica , Mapas de Interação de Proteínas , Proteoma , Transdução de SinaisRESUMO
PURPOSE: Phosphodiesterase 5A (PDE5A) inhibitors improve functional recovery in experimental models of stroke in rats when treatment is delayed and without effect on infarct volume. PDE5A is expressed to only a very limited extent in forebrain tissues, raising the possibility that the locus of effect for the inhibitors is outside the brain. To start to address this question, we determined whether PDE5A inhibitors must have the ability to cross the blood brain barrier to improve recovery. METHOD: After permanent middle cerebral artery occlusion in rats, PF-5 and UK-489,791, PDE5A inhibitors that do or do not pass the blood brain barrier, were administered starting 24 h after occlusion and continued for 1 week. Motor function was assessed at intervals to 28 days using body swing and limb placement measures. RESULTS: Both PF-5 and UK-489,791 produced improvement in motor scores over 28 days that were significantly greater than in vehicle treated animals. There was no difference in efficacy between the two PDE5A inhibitors. CONCLUSIONS: Brain penetrability appears not to be critical to the ability of a PDE5A inhibitor to improve functional recovery after experimental stroke in rats. This finding is discussed with regard to the cellular target(s) for PDE5A inhibitors mediating this effect.
Assuntos
Infarto da Artéria Cerebral Média/tratamento farmacológico , Inibidores da Fosfodiesterase 5/farmacologia , Recuperação de Função Fisiológica/efeitos dos fármacos , Acidente Vascular Cerebral/tratamento farmacológico , Animais , Comportamento Animal/efeitos dos fármacos , Encéfalo/irrigação sanguínea , Encéfalo/efeitos dos fármacos , Modelos Animais de Doenças , Infarto da Artéria Cerebral Média/fisiopatologia , Masculino , Atividade Motora/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Ratos , Ratos Sprague-Dawley , Acidente Vascular Cerebral/fisiopatologia , Fatores de TempoRESUMO
In gray matter, cerebral endothelium is known to provide trophic support for neighboring cells such as neurons. However, signaling from cerebral endothelium to white matter cells remains to be elucidated. Here, we show that vascular endothelial growth factor (VEGF-A) secreted from cerebral endothelial cells promotes the migration but not the proliferation of oligodendrocyte precursor cells (OPCs). Cultured OPCs were obtained from newborn rat cortex, and treatment with conditioned culture media of cerebral endothelial cells increased the OPC proliferation and migration. Importantly, co-treatment with anti-neutralizing antibody for Flk-1 (VEGF-receptor2) inhibited OPC movement but did not affect OPC propagation. Western blot and flow cytometry analyses confirmed that our cultured cerebral endothelial cells produced VEGF-A and our cultured OPCs expressed Flk-1. Taken together, our current data suggest that cerebral endothelium is supportive for oligodendrocyte lineage cells and VEGF-A may participate in the endothelium-OPC cell-cell signaling. This phenomenon may be important for white matter homeostasis.