scholarly journals Plasmin-Dependent Modulation of the Blood–Brain Barrier: A Major Consideration during tPA-Induced Thrombolysis?

2014 ◽  
Vol 34 (8) ◽  
pp. 1283-1296 ◽  
Author(s):  
Be'eri Niego ◽  
Robert L Medcalf
Keyword(s):  
Ischemic Stroke ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Tissue Type ◽  
Ischemic Event ◽  
Tissue Type Plasminogen Activator ◽  
Rational Case ◽  
Blood Brain ◽  
Type Plasminogen Activator ◽  
Major Consideration

Plasmin, the principal downstream product of tissue-type plasminogen activator (tPA), is known for its potent fibrin-degrading capacity but is also recognized for many non-fibrinolytic activities. Curiously, plasmin has not been conclusively linked to blood–brain barrier (BBB) disruption during recombinant tPA (rtPA)-induced thrombolysis in ischemic stroke. This is surprising given the substantial involvement of tPA in the modulation of BBB permeability and the co-existence of tPA and plasminogen in both blood and brain throughout the ischemic event. Here, we review the work that argues a role for plasmin together with endogenous tPA or rtPA in BBB alteration, presenting the overall controversy around the topic yet creating a rational case for an involvement of plasmin in this process.

scholarly journals Tissue-type plasminogen activator induces opening of the blood-brain barrier via the LDL receptor–related protein

2003 ◽  
Vol 112 (10) ◽  
pp. 1533-1540 ◽  
Author(s):  
Manuel Yepes ◽  
Maria Sandkvist ◽  
Elizabeth G. Moore ◽  
Thomas H. Bugge ◽  
Dudley K. Strickland ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Blood Brain Barrier ◽  
Ldl Receptor ◽  
Brain Barrier ◽  
Tissue Type ◽  
Related Protein ◽  
Tissue Type Plasminogen Activator ◽  
Blood Brain ◽  
Type Plasminogen Activator

Tissue-type plasminogen activator induces TNF-α-mediated preconditioning of the blood-brain barrier

2021 ◽  
pp. 0271678X2110603
Author(s):  
Ariel Diaz ◽  
Yena Woo ◽  
Cynthia Martin-Jimenez ◽  
Paola Merino ◽  
Enrique Torre ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Blood Brain Barrier ◽  
Neuronal Survival ◽  
Ischemic Tolerance ◽  
Brain Barrier ◽  
Tissue Type ◽  
Ischemic Insult ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Tnf Α

Ischemic tolerance is a phenomenon whereby transient exposure to a non-injurious preconditioning stimulus triggers resistance to a subsequent lethal ischemic insult. Despite the fact that not only neurons but also astrocytes and endothelial cells have a unique response to preconditioning stimuli, current research has been focused mostly on the effect of preconditioning on neuronal death. Thus, it is unclear if the blood-brain barrier (BBB) can be preconditioned independently of an effect on neuronal survival. The release of tissue-type plasminogen activator (tPA) from perivascular astrocytes in response to an ischemic insult increases the permeability of the BBB. In line with these observations, treatment with recombinant tPA increases the permeability of the BBB and genetic deficiency of tPA attenuates the development of post-ischemic edema. Here we show that tPA induces ischemic tolerance in the BBB independently of an effect on neuronal survival. We found that tPA renders the BBB resistant to an ischemic injury by inducing TNF-α-mediated astrocytic activation and increasing the abundance of aquaporin-4-immunoreactive astrocytic end-feet processes in the neurovascular unit. This is a new role for tPA, that does not require plasmin generation, and with potential therapeutic implications for patients with cerebrovascular disease.

scholarly journals Pinocembrin Protects Blood-Brain Barrier Function and Expands the Therapeutic Time Window for Tissue-Type Plasminogen Activator Treatment in a Rat Thromboembolic Stroke Model

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
YinZhong Ma ◽  
Li Li ◽  
LingLei Kong ◽  
ZhiMei Zhu ◽  
Wen Zhang ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Plasminogen Activator ◽  
Blood Brain Barrier ◽  
Time Window ◽  
Tissue Type ◽  
Stroke Model ◽  
Thromboembolic Stroke ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Therapeutic Time Window

Tissue-type plasminogen activator (t-PA) remains the only approved therapy for acute ischemic stroke but has a restrictive treatment time window of 4.5 hr. Prolonged ischemia causes blood-brain barrier (BBB) damage and increases the incidence of hemorrhagic transformation (HT) secondary to reperfusion. In this study, we sought to determine the effect of pinocembrin (PCB; a pleiotropic neuroprotective agent) on t-PA administration-induced BBB damage in a novel rat thromboembolic stroke model. By assessing the leakage of Evans blue into the ischemic hemisphere, we demonstrated that PCB pretreatment 5 min before t-PA administration significantly reduced BBB damage following 2 hr, 4 hr, 6 hr, and even 8 hr ischemia. Consistently, PCB pretreatment significantly decreased t-PA infusion-resulting brain edema and infarction volume and improved the behavioral outcomes following 6 hr ischemia. Mechanistically, PCB pretreatment inhibited the activation of MMP-2 and MMP-9 and degradation of tight junction proteins (TJPs) occludin and claudin-5 in the ischemic hemisphere. Moreover, PCB pretreatment significantly reduced phosphorylation of platelet-derived growth factor receptor α (PDGFRα) as compared with t-PA alone. In an in vitro BBB model, PCB decreased transendothelial permeability upon hypoxia/aglycemia through inhibiting PDGF-CC secretion. In conclusion, we demonstrated that PCB pretreatment shortly before t-PA infusion significantly protects BBB function and improves neurological outcomes following prolonged ischemia beyond the regular 4.5 hr t-PA time window. PCB pretreatment may represent a novel means of increasing the safety and the therapeutic time window of t-PA following ischemic stroke.

scholarly journals Sustained Opening of the Blood-Brain Barrier with Progressive Accumulation of White Matter Hyperintensities Following Ischemic Stroke

2019 ◽  
Vol 9 (1) ◽  
pp. 16 ◽  
Author(s):  
Imama Naqvi ◽  
Emi Hitomi ◽  
Richard Leigh
Keyword(s):  
Ischemic Stroke ◽  
White Matter ◽  
Acute Stroke ◽  
Blood Brain Barrier ◽  
White Matter Hyperintensities ◽  
Brain Barrier ◽  
Common Finding ◽  
Blood Brain ◽  
History Of ◽  
Iv Tpa

Objective: To report a patient in whom an acute ischemic stroke precipitated chronic blood-brain barrier (BBB) disruption and expansion of vascular white matter hyperintensities (WMH) into regions of normal appearing white matter (NAWM) during the following year. Background: WMH are a common finding in patients with vascular risk factors such as a history of stroke. The pathophysiology of WMH is not fully understood; however, there is growing evidence to suggest that the development of WMH may be preceded by the BBB disruption in the NAWM. Methods: We studied a patient enrolled in the National Institutes of Health Natural History of Stroke Study who was scanned with magnetic resonance imaging (MRI) after presenting to the emergency room with an acute stroke. After a treatment with IV tPA, she underwent further MRI scanning at 2 h, 24 h, 5 days, 30 days, 90 days, 6 months, and 1-year post stroke. BBB permeability images were generated from the perfusion weighted imaging (PWI) source images. MRIs from each time point were co-registered to track changes in BBB disruption and WMH over time. Results: An 84-year-old woman presented after acute onset right hemiparesis, right-sided numbness and aphasia with an initial NIHSS of 13. MRI showed diffusion restriction in the left frontal lobe and decreased blood flow on perfusion imaging. Fluid attenuated inversion recovery (FLAIR) imaging showed bilateral confluent WMH involving the deep white matter and periventricular regions. She was treated with IV tPA without complication and her NIHSS improved initially to 3 and ultimately to 0. Permeability maps identified multiple regions of chronic BBB disruption remote from the acute stroke, predominantly spanning the junction of WMH and NAWM. The severity of BBB disruption was greatest at 24 h after the stroke but persisted on subsequent MRI scans. Progression of WMH into NAWM over the year of observation was detected bilaterally but was most dramatic in the regions adjacent to the initial stroke. Conclusions: WMH-associated BBB disruption may be exacerbated by an acute stroke, even in the contralateral hemisphere, and can persist for months after the initial event. Transformation of NAWM to WMH may be evident in areas of BBB disruption within a year after the stroke. Further studies are needed to investigate the relationship between chronic BBB disruption and progressive WMH in patients with a history of cerebrovascular disease and the potential for acute stroke to trigger or exacerbate the process leading to the development of WMH.

scholarly journals Could Lipoxins Represent a New Standard in Ischemic Stroke Treatment?

2021 ◽  
Vol 22 (8) ◽  
pp. 4207
Author(s):  
Nikola Tułowiecka ◽  
Dariusz Kotlęga ◽  
Andrzej Bohatyrewicz ◽  
Małgorzata Szczuko
Keyword(s):  
Ischemic Stroke ◽  
Cardiovascular Diseases ◽  
Blood Brain Barrier ◽  
Inflammatory Cytokines ◽  
The Body ◽  
Brain Barrier ◽  
Lipoxin A4 ◽  
Stroke Treatment ◽  
Blood Brain ◽  
Anti Inflammatory

Introduction: Cardiovascular diseases including stroke are one of the most common causes of death. Their main cause is atherosclerosis and chronic inflammation in the body. An ischemic stroke may occur as a result of the rupture of unstable atherosclerotic plaque. Cardiovascular diseases are associated with uncontrolled inflammation. The inflammatory reaction produces chemical mediators that stimulate the resolution of inflammation. One of these mediators is lipoxins—pro-resolving mediators that are derived from the omega-6 fatty acid family, promoting inflammation relief and supporting tissue regeneration. Aim: The aim of the study was to review the available literature on the therapeutic potential of lipoxins in the context of ischemic stroke. Material and Methods: Articles published up to 31 January 2021 were included in the review. The literature was searched on the basis of PubMed and Embase in terms of the entries: ‘stroke and lipoxin’ and ‘stroke and atherosclerosis’, resulting in over 110 articles in total. Studies that were not in full-text English, letters to the editor, and conference abstracts were excluded. Results: In animal studies, the injection/administration of lipoxin A4 improved the integrity of the blood–brain barrier (BBB), decreased the volume of damage caused by ischemic stroke, and decreased brain edema. In addition, lipoxin A4 inhibited the infiltration of neutrophils and the production of cytokines and pro-inflammatory chemokines, such as interleukin (Il-1β, Il-6, Il-8) and tumor necrosis factor-α (TNF-α). The beneficial effects were also observed after introducing the administration of lipoxin A4 analog—BML-111. BML-111 significantly reduces the size of a stroke and protects the cerebral cortex, possibly by reducing the permeability of the blood–brain barrier. Moreover, more potent than lipoxin A4, it has an anti-inflammatory effect by inhibiting the production of pro-inflammatory cytokines and increasing the amount of anti-inflammatory cytokines. Conclusions: Lipoxins and their analogues may find application in reducing damage caused by stroke and improving the prognosis of patients after ischemic stroke.

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