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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In acute ischemic stroke, collateral circulation plays an important role in maintaining blood flow to the tissue that is at risk of progressing into ischemia, and in increasing the successful recanalization rate without hemorrhagic transformation. We have reported that well-developed collateral circulation is associated with smaller infarct volume and better long-term neurological outcome, and it disappears promptly once the effective recanalization is achieved. Contrary to the belief that collateral vessels develop over time in chronic stenotic condition, there exists a phenomenon that collateral circulation develops immediately in acute stenosis or occlusion of the arteries and it seems to be triggered by fluid shear stress, which occurs between the territories of stenotic/occluded arteries and those fed by surrounding intact arteries. We believe that this acute development of collateral circulation is a target of novel therapeutics in ischemic stroke and refer our recent attempt in enhancing collateral circulation by modulating sphingosine-1-phosphate receptor 1, which is a known shear-stress mechanosensing protein.
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PMID:Acute development of collateral circulation and therapeutic prospects in ischemic stroke. 2712 59

Blood-brain barrier (BBB) disruption is a common pathological feature of many neurological disorders including stroke and brain trauma, therefore is an important therapeutic target for treatment of these diseases. Basic fibroblast growth factor (bFGF) as a member of FGF superfamily plays critical roles in angiogenesis, neurogenesis, and neuron survival. We recently showed that recombinant bFGF protects against BBB disruption in traumatic brain injury in mice. In this study, we further investigated the mechanisms of recombinant bFGF in BBB protection by measuring the permeability of cultured endothelial cell monolayer induced by oxygen-glucose deprivation and reoxygenation (OGD/R). We found that recombinant bFGF significantly decreased OGD/R-induced permeability of primary human brain microvascular endothelial cell (HBMEC) monolayer and preserved OGD/R-induced decreases of trans-endothelial electrical resistance (TEER). Western blot and immunocytochemistry showed that bFGF significantly rescued OGD/R-induced downregulation of junction proteins ZO-1, occludin, and VE-cadherin. We further show that the BBB protective effect of bFGF is via FGF receptor 1 (FGFR1) activation as FGFR1 inhibitor can block this protection effect. Moreover, we revealed that the BBB protection effect of bFGF is at least partially through rescuing the OGD/R-induced downregulation of sphingosine-1-phosphate receptor 1 (S1PR1) protein, as S1PR1 inhibitor or SIPR1 small interfering RNA blocked the BBB protective effect of bFGF, whereas S1PR1 agonist alone has comparable BBB protection effect of bFGF. These findings will improve our understanding of the protective effect and mechanisms of bFGF on BBB and propose bFGF as a potential therapeutic agent against BBB damage in neurological disorders.
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PMID:bFGF Protects Against Oxygen Glucose Deprivation/Reoxygenation-Induced Endothelial Monolayer Permeability via S1PR1-Dependent Mechanisms. 2846 72

Ischemic strokes account for about 80% of all strokes and are associated with a high risk of mortality. Angiogenesis of brain microvascular endothelial cells may contribute to functional restoration following ischemia. Fibroblast growth factor 1 (FGF1), a member of FGF superfamily, involved in embryonic development, angiogenesis, wound healing, and neuron survival. However, the mitogenic activity of FGF1 is known to contribute to several human pathologies, thereby questioning the safety of its clinical applications. Here, we explored the effects and mechanism of action of non-mitogenic FGF1 (nmFGF1) on angiogenesis in mice after ischemia stroke and an oxygen-glucose deprivation (OGD)-induced human brain microvascular endothelial cells (HBMECs) injury model. We found that intranasal administration nmFGF1 significantly promoted angiogenesis in mice after stroke, and significantly increased the formation of matrigel tube and promoted scratch migration in a dose-dependent manner in OGD-induced HBMECs in vitro. However, the co-administration of an FGF receptor 1 (FGFR1)-specific inhibitor PD173074 significantly reversed the effects of nmFGF1 in vitro, suggesting that nmFGF1 functions via FGFR1 activation. Moreover, nmFGF1 activated sphingosine-1-phosphate receptor 1 (S1PR1, S1P1) in mice after stroke in vivo. S1P1 protein antagonist VPC23019 and agonist FTY720 were used to confirm that nmFGF1 promotes angiogenesis in vitro partially through the S1P1 pathway. OGD induced downregulation of S1P1 expression. The S1P1 antagonist VPC23019 blocked the stimulatory effects of nmFGF1, whereas the S1P1 agonist FTY720 exerted effects comparable with those of nmFGF1. Furthermore, PD173074 reversed the effect of nmFGF1 on upregulating S1P1 signaling. In conclusion, nmFGF1 enhanced angiogenesis in mice following stroke and OGD-induced HBMECs through S1P1 pathway regulation mediated via FGFR1 activation. This new discovery suggests the potential therapeutic role of nmFGF1 for the treatment of ischemic strokes.
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PMID:Non-Mitogenic Fibroblast Growth Factor 1 Enhanced Angiogenesis Following Ischemic Stroke by Regulating the Sphingosine-1-Phosphate 1 Pathway. 3219 96

Rationale: Hemorrhagic complications represent a major limitation of intravenous thrombolysis using tissue plasminogen activator (tPA) in patients with ischemic stroke. The expression of tPA receptors on immune cells raises the question of what effects tPA exerts on these cells and whether these effects contribute to thrombolysis-related hemorrhagic transformation. Objective: We aim to determine the impact of tPA on immune cells and investigate the association between observed immune alteration with hemorrhagic transformation in ischemic stroke patients and in a rat model of embolic stroke. Methods and Results: Paired blood samples were collected before and 1 hour after tPA infusion from 71 ischemic stroke patients. Control blood samples were collected from 27 ischemic stroke patients without tPA treatment. A rat embolic middle cerebral artery occlusion model was adopted to investigate the underlying mechanisms of hemorrhagic transformation. We report that tPA induces a swift surge of circulating neutrophils and T cells with profoundly altered molecular features in ischemic stroke patients and a rat model of focal embolic stroke. tPA exacerbates endothelial injury, increases adhesion and migration of neutrophils and T cells, which are associated with brain hemorrhage in rats subjected to embolic stroke. Genetic ablation of annexin A2 in neutrophils and T cells diminishes the effect of tPA on these cells. Decoupling the interaction between mobilized neutrophils/T cells and the neurovascular unit, achieved via a sphingosine-1-phosphate receptor 1 modulator RP101075 and a CCL2 synthesis inhibitor bindarit, which block lymphocyte egress and myeloid cell recruitment, respectively, attenuates hemorrhagic transformation and improves neurological function after tPA thrombolysis. Conclusions: Our findings suggest that immune invasion of the neurovascular unit represents a previously unrecognized mechanism underlying tPA-mediated brain hemorrhage, which can be overcome by precise immune modulation during thrombolytic therapy.
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PMID:tPA Mobilizes Immune Cells that Exacerbate Hemorrhagic Transformation in Stroke. 3307 Jul 17