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Karen-Sue B Carlson, Lan Nguyen, Kat Schwartz, Daniel A Lawrence, Bradford S Schwartz
Tissue-type plasminogen activator (t-PA), initially characterized for its critical role in fibrinolysis, also has key functions in both physiologic and pathologic processes in the CNS. Neuroserpin (NSP) is a t-PA specific serine protease inhibitor (serpin) found almost exclusively in the CNS that regulates t-PA's proteolytic activity and protects against t-PA mediated seizure propagation and blood-brain barrier disruption. This report demonstrates that NSP inhibition of t-PA varies profoundly as a function of pH within the biologically relevant pH range for the CNS, and reflects the stability, rather than the formation of NSP: t-PA acyl-enzyme complexes...
2016: Frontiers in Cellular Neuroscience
Han-Sen Chen, Su-Hua Qi, Jian-Gang Shen
Tissue plasminogen activator (t-PA) is the only FDA-approved drug for acute ischemic stroke treatment, but its clinical use is limited due to the narrow therapeutic time window and severe adverse effects, including hemorrhagic transformation (HT) and neurotoxicity. One of the potential resolutions is to use adjunct therapies to reduce the side effects and extend t-PA's therapeutic time window. However, therapies modulating single target seem not to be satisfied, and a multitarget strategy is warranted to resolve such complex disease...
2017: Current Neuropharmacology
Marianne Petro, Hayder Jaffer, Jun Yang, Shushi Kabu, Viola B Morris, Vinod Labhasetwar
Inherent neuronal and circulating progenitor cells play important roles in facilitating neuronal and functional recovery post stroke. However, this endogenous repair process is rather limited, primarily due to unfavorable conditions in the infarcted brain involving reactive oxygen species (ROS)-mediated oxidative stress and inflammation following ischemia/reperfusion injury. We hypothesized that during reperfusion, effective delivery of antioxidants to ischemic brain would create an environment without such oxidative stress and inflammation, thus promoting activation and mobilization of progenitor cells in the infarcted brain...
March 2016: Biomaterials
Han-Sen Chen, Su-Hua Qi, Jian-Gang Shen
Tissue plasminogen activator (t-PA) is the only FDA approved drug for acute ischemic stroke treatment, but its clinical use is limited due to the narrow therapeutic time window and severe adverse effects, including hemorrhagic transformation (HT) and neurotoxicity. One of the potential resolutions is to use adjunct therapies to reduce the side effects and extend t-PA's therapeutic time window. However, therapies modulating single target seems not satisfying, and a multi-target strategy is warranted to resolve such complex disease...
December 7, 2015: Current Neuropharmacology
Tatsuya Fukuta, Takayuki Ishii, Tomohiro Asai, Akihiko Sato, Takashi Kikuchi, Kosuke Shimizu, Tetsuo Minamino, Naoto Oku
Since the proportion of patients given thrombolytic therapy with tissue plasminogen activator (t-PA) is very limited because of the narrow therapeutic window, the development of new therapies for ischemic stroke has been desired. We previously reported that liposomes injected intravenously accumulate in the ischemic region of the brain via disruption of the blood-brain barrier that occurs under cerebral ischemia. In the present study, we investigated the efficacy of a liposomal neuroprotective agent in middle cerebral artery occlusion (MCAO) rats to develop ischemic stroke therapy prior to the recovery of cerebral blood flow...
November 2015: European Journal of Pharmaceutics and Biopharmaceutics
Juhua Pan, Xiaoming Lei, Jialong Wang, Shijing Huang, Yanyun Wang, Ying Zhang, Wen Chen, Duojiao Li, Jun Zheng, Hanming Cui, Qihua Liu
BACKGROUND: Kaixinjieyu (KJ), derived from Kaixin and Sini powder, is an effective Chinese herbal medicine preparation used in the treatment of vascular depression (VD). We hypothesize that broad antidepressant effect of KJ results from the improved neurovascular unit (NVU) function via neurogenesis, permeability of blood-brain barrier (BBB) and balance of the fibrinolytic system. METHODS: A VD model of rat was established by chronic unpredictable mild stress and separation after ligation of the bilateral common carotid arteries...
2015: BMC Complementary and Alternative Medicine
Li Ma, Hui Zhang, Yong-zhe Liu, Yan-ling Yin, Ya-qun Ma, Sheng-suo Zhang
Tissue-type plasminogen activator (t-PA) and matrix metalloproteinase-9 (MMP-9) have been reported to play important roles in increased permeability of blood-brain barrier (BBB) under many pathological circumstances. We have showed that Ulinastatin, a broad-spectrum serine protease inhibitor, could alleviate inflammation in the hippocampus of aged rats following partial hepatectomy. In this study, we investigate the expression and potential roles of t-PA and MMP-9 in the protective effect of Ulinastatin. We found that partial hepatectomy increased Evans blue leakage in hippocampus at day 1 and 3 postoperatively...
2016: International Journal of Neuroscience
Yolanda Cruz, Jonathan Lorea, Humberto Mestre, Jennifer Hyuna Kim-Lee, Judith Herrera, Raúl Mellado, Vanesa Gálvez, Leopoldo Cuellar, Carolina Musri, Antonio Ibarra
Stroke triggers a systemic inflammatory response that exacerbates the initial injury. Immunizing with peptides derived from CNS proteins can stimulate protective autoimmunity (PA). The most renowned of these peptides is copolymer-1 (Cop-1) also known as glatiramer acetate. This peptide has been approved for use in the treatment of multiple sclerosis. Cop-1-specific T cells cross the blood-brain barrier and secrete neurotrophins and anti-inflammatory cytokines that could stimulate proliferation of neural precursor cells and recruit them to the injury site; making it an ideal therapy for acute ischemic stroke...
2015: PloS One
Winfried Neuhaus, Fabian Gaiser, Anne Mahringer, Jonas Franz, Christoph Riethmüller, Carola Förster
Stabilization of the blood-brain barrier during and after stroke can lead to less adverse outcome. For elucidation of underlying mechanisms and development of novel therapeutic strategies validated in vitro disease models of the blood-brain barrier could be very helpful. To mimic in vitro stroke conditions we have established a blood-brain barrier in vitro model based on mouse cell line cerebEND and applied oxygen/glucose deprivation (OGD). The role of astrocytes in this disease model was investigated by using cell line C6...
2014: Frontiers in Cellular Neuroscience
Brandon J Thompson, Patrick T Ronaldson
Cerebral ischemia occurs when blood flow to the brain is insufficient to meet metabolic demand. This can result from cerebral artery occlusion that interrupts blood flow, limits CNS supply of oxygen and glucose, and causes an infarction/ischemic stroke. Ischemia initiates a cascade of molecular events in neurons and cerebrovascular endothelial cells including energy depletion, dissipation of ion gradients, calcium overload, excitotoxicity, oxidative stress, and accumulation of ions and fluid. Blood-brain barrier (BBB) disruption is associated with cerebral ischemia and leads to vasogenic edema, a primary cause of stroke-associated mortality...
2014: Advances in Pharmacology
Takehiko Nagao
Thrombolytic agents positively resolve existing thrombi by accelerating the activity of plasmin, a key enzyme of the fibrinolytic pathway. The main drug in use is a plasminogen activator (PA) which degrades plasminogen to plasmin. PA is classified into urokinase-type (u-PA) and tissue-type (t-PA). Because t-PA more selectively activates plasmin onto the surface of thrombi, it induces less in terms of systemic hemorrhagic complications. Beside the main effects, some articles have reported that t-PA causes damage to blood brain barrier structures and has a level of neuron toxicity...
July 2014: Nihon Rinsho. Japanese Journal of Clinical Medicine
Roxann Freeman, Be'eri Niego, David R Croucher, Lars O Pedersen, Robert L Medcalf
Tissue-type plasminogen activator (t-PA) is the only thrombolytic treatment available for patients with acute ischaemic stroke. However, t-PA can increase permeability of the blood-brain barrier (BBB). Desmoteplase is a plasminogen activator derived from the common vampire bat, currently under clinical development for ischaemic stroke. We compared how t-PA and desmoteplase influenced BBB permeability using a human in vitro model where primary brain endothelial cells (BEC) and astrocytes are co-cultured on the opposite sides of a porous membrane...
May 27, 2014: Brain Research
Laura Bana, Stefania Minniti, Elisa Salvati, Silvia Sesana, Vanessa Zambelli, Alfredo Cagnotto, Antonina Orlando, Emanuela Cazzaniga, Rob Zwart, Wiep Scheper, Massimo Masserini, Francesca Re
Targeting amyloid-β peptide (Aβ) within the brain is a strategy actively sought for therapy of Alzheimer's disease (AD). We investigated the ability of liposomes bi-functionalized with phosphatidic acid and with a modified ApoE-derived peptide (mApoE-PA-LIP) to affect Aβ aggregation/disaggregation features and to cross in vitro and in vivo the blood-brain barrier (BBB). Surface plasmon resonance showed that bi-functionalized liposomes strongly bind Aβ (kD=0.6 μM), while Thioflavin-T and SDS-PAGE/WB assays show that liposomes inhibit peptide aggregation (70% inhibition after 72 h) and trigger the disaggregation of preformed aggregates (60% decrease after 120 h incubation)...
October 2014: Nanomedicine: Nanotechnology, Biology, and Medicine
Zhongling Zhang, Xuhui Chen, Le Li, Keling Zhang, Shuqing Tian, Hongmei Gao, Hulun Li
Cerebral ischemic stroke is one of the most prevalent diseases in senior individuals. Its therapeutical strategies include anticoagulation, thrombolysis and cell protection. Tissue-type plasminogen activator (t-PA) that interacts with thrombin for the lysis of thrombosis is widely used to treat stroke patients in early stage. The mechanism of action of t-PA is not clear. Here, we report a novel role of t-PA in protecting blood-brain barrier and its potential mechanisms. In a model of the blood-brain barrier with human umbilical vascular epithelium cells, we found that t-PA in low concentrations prevented the impairment of the blood-brain barrier as a result of oxygen and glucose deprivation...
September 2013: Neurological Sciences
Saida Ortolano, Carlos Spuch
A growing body of evidence has implicated the plasminogen activating system in various aspects of neurophysiology and pathophysiology. In ischemic stroke, blood-brain barrier (BBB) regulations, typically involving matrix metalloproteinases (MMPs), inhibitors tissue inhibitors of metalloproteinases (TIMPs) and the low density lipoprotein receptor- related protein/alpha 2-macroglobulin receptor (LRPs) as mediators became interesting since tissue plasminogen activator (tPA)-related BBB breakdown with risk of secondary hemorrhage was considered to involve these mediators too...
January 2013: Recent Patents on Endocrine, Metabolic & Immune Drug Discovery
Yu-Chieh Chen, Jiunn-Ming Sheen, You-Lin Tain, Chih-Cheng Chen, Miao-Meng Tiao, Ying-Hsien Huang, Chih-Sung Hsieh, Li-Tung Huang
Bile duct ligation (BDL)-treated rats exhibit cholestasis and increased systemic and brain oxidative stress. Activation of NADPH (nicotinamide adenine dinucleotide phosphate) oxidase and disruption of the blood-brain barrier (BBB) are implicated as the pathogenetic mechanisms of brain dysfunction in BDL-treated adult rats. Young rats underwent sham ligation or BDL at day 17 for 2 or 4weeks. Treatment group rats were administered melatonin between day 17 and 45. We found a progressive increase in prefrontal cortex NADPH-dependent superoxide anion (O(2)(-)) production and increased expression of NADPH oxidase subunits in either the prefrontal cortex or the hippocampus in BDL-treated young rats...
June 2012: Neurochemistry International
Be'eri Niego, Roxann Freeman, Till B Puschmann, Ann M Turnley, Robert L Medcalf
Tissue-type plasminogen activator (t-PA) can modulate permeability of the neurovascular unit and exacerbate injury in ischemic stroke. We examined the effects of t-PA using in vitro models of the blood-brain barrier. t-PA caused a concentration-dependent increase in permeability. This effect was dependent on plasmin formation and potentiated in the presence of plasminogen. An inactive t-PA variant inhibited the t-PA-mediated increase in permeability, whereas blockade of low-density lipoprotein receptors or exposed lysine residues resulted in similar inhibition, implying a role for both a t-PA receptor, most likely a low-density lipoprotein receptor, and a plasminogen receptor...
May 17, 2012: Blood
Hayder Jaffer, Viola B Morris, Desiree Stewart, Vinod Labhasetwar
Stroke is a leading cause of death, long-term disability, and socioeconomic costs, highlighting the urgent need for more effective treatments. Intravenous administration of tissue plasminogen activator (t-PA) is the only FDA-approved therapy to re-establish cerebral blood flow. However, because of increased risk of hemorrhage beyond 3 h post stroke, few stroke patients (1-2%) benefit from t-PA; t-PA, which has neurotoxic effects, can also aggravate the extent of reperfusion injury by increasing blood-brain barrier permeability...
December 1, 2011: Drug Delivery and Translational Research
Toru Yamashita, Koji Abe
Reperfusion with recombinant tissue plasminogen activator (tPA) sometimes causes catastrophic hemorrhagic transformation (HT) in the ischemic brain. Consequently, the application of tPA has been strictly limited. Recent studies have indicated that matrix metalloproteinases (MMPs), especially MMP-9, play a critical role in blood brain barrier (BBB) disruption in the ischemic brain, leading to brain edema and HT. In the ischemic brain, free radicals and exogenous tPA itself can trigger MMP-9 activation through several signaling pathways containing LDL receptor-related protein (LRP) and proteinase-activated receptor 1 (PAR1)...
August 2011: Acta Medica Okayama
Robert L Medcalf
The plasminogen activating enzyme system has been exploited and harnessed for therapeutic, mainly thrombolytic benefit for many years. While plasminogen activator-based thrombolysis turned out to be a resounding success, it has become apparent that the "plasminogen activating system" per se is not only designed to simply remove fibrin and some other matrix proteins. Indeed, the plasminogen activators and the plasminogen activator inhibitors have important effects on cell signalling through both proteolytic and non-proteolytic means and can promote unwanted side effects, particularly in the brain...
November 2011: Current Drug Targets
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