1
|
Krakovsky M, Polianski V, Nimrod A, Higazi A, Leker RR, Lamensdorf I. THR-18, a 18-mer peptide derived from PAI-1, is neuroprotective and improves thrombolysis by tPA in rat stroke models. Neurol Res 2013; 33:983-90. [DOI: 10.1179/1743132811y.0000000018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
2
|
Nassar T, Yarovoi S, Fanne RA, Waked O, Allen TC, Idell S, Cines DB, Higazi AAR. Urokinase plasminogen activator regulates pulmonary arterial contractility and vascular permeability in mice. Am J Respir Cell Mol Biol 2011; 45:1015-21. [PMID: 21617202 DOI: 10.1165/rcmb.2010-0302oc] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The concentration of urokinase plasminogen activator (uPA) is elevated in pathological settings such as acute lung injury, where pulmonary arterial contractility and permeability are disrupted. uPA limits the accretion of fibrin after injury. Here we investigated whether uPA also regulates pulmonary arterial contractility and permeability. Contractility was measured using isolated pulmonary arterial rings. Pulmonary blood flow was measured in vivo by Doppler and pulmonary vascular permeability, according to the extravasation of Evans blue. Our data show that uPA regulates the in vitro pulmonary arterial contractility induced by phenylephrine in a dose-dependent manner through two receptor-dependent pathways, and regulates vascular contractility and permeability in vivo. Physiological concentrations of uPA (≤1 nM) stimulate the contractility of pulmonary arterial rings induced by phenylephrine through the low-density lipoprotein receptor-related protein receptor. The procontractile effect of uPA is independent of its catalytic activity. At pathophysiological concentrations, uPA (20 nM) inhibits contractility and increases vascular permeability. The inhibition of vascular contractility and increase of vascular permeability is mediated through a two-step process that involves docking to N-methyl-d-aspartate receptor-1 (NMDA-R1) on pulmonary vascular smooth muscle cells, and requires catalytic activity. Peptides that specifically inhibit the docking of uPA to NMDA-R, or the uPA variant with a mutated receptor docking site, abolished both the effects of uPA on vascular contractility and permeability, without affecting its catalytic activity. These data show that uPA, at concentrations found under pathological conditions, reduces pulmonary arterial contractility and increases permeability though the activation of NMDA-R1. The selective inhibition of NMDAR-1 activation by uPA can be accomplished without a loss of fibrinolytic activity.
Collapse
Affiliation(s)
- Taher Nassar
- Department of Pathology, Laboratory Medicine, University of Pennsylvania, Philadelphia, 19104, USA
| | | | | | | | | | | | | | | |
Collapse
|
3
|
Attwell D, Buchan AM, Charpak S, Lauritzen M, Macvicar BA, Newman EA. Glial and neuronal control of brain blood flow. Nature 2010; 468:232-43. [PMID: 21068832 PMCID: PMC3206737 DOI: 10.1038/nature09613] [Citation(s) in RCA: 1640] [Impact Index Per Article: 117.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now recognized that neurotransmitter-mediated signalling has a key role in regulating cerebral blood flow, that much of this control is mediated by astrocytes, that oxygen modulates blood flow regulation, and that blood flow may be controlled by capillaries as well as by arterioles. These conceptual shifts in our understanding of cerebral blood flow control have important implications for the development of new therapeutic approaches.
Collapse
Affiliation(s)
- David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK.
| | | | | | | | | | | |
Collapse
|
4
|
Harston GWJ, Sutherland BA, Kennedy J, Buchan AM. The contribution of L-arginine to the neurotoxicity of recombinant tissue plasminogen activator following cerebral ischemia: a review of rtPA neurotoxicity. J Cereb Blood Flow Metab 2010; 30:1804-16. [PMID: 20736961 PMCID: PMC3023931 DOI: 10.1038/jcbfm.2010.149] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Alteplase is the only drug licensed for acute ischemic stroke, and in this formulation, the thrombolytic agent recombinant tissue plasminogen activator (rtPA) is stabilized in a solution of L-arginine. Improved functional outcomes after alteplase administration have been shown in clinical trials, along with improved histological and behavioral measures in experimental models of embolic stroke. However, in animal models of mechanically induced ischemia, alteplase can exacerbate ischemic damage. We have systematically reviewed the literature of both rtPA and L-arginine administration in mechanical focal ischemia. The rtPA worsens ischemic damage under certain conditions, whereas L-arginine can have both beneficial and deleterious effects dependent on the time of administration. The interaction between rtPA and L-arginine may be leading to the production of nitric oxide, which can cause direct neurotoxicity, altered cerebral blood flow, and disruption of the neurovascular unit. We suggest that alternative formulations of rtPA, in the absence of L-arginine, would provide new insight into rtPA neurotoxicity, and have the potential to offer more efficacious thrombolytic therapy for ischemic stroke patients.
Collapse
Affiliation(s)
- George W J Harston
- Nuffield Department of Clinical Medicine, Acute Stroke Programme, University of Oxford, Oxford, UK
| | | | | | | |
Collapse
|
5
|
Toda N, Ayajiki K, Okamura T. Cerebral Blood Flow Regulation by Nitric Oxide: Recent Advances. Pharmacol Rev 2009; 61:62-97. [DOI: 10.1124/pr.108.000547] [Citation(s) in RCA: 268] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
|
6
|
Kreipke CW, Rafols JA. Calponin control of cerebrovascular reactivity: therapeutic implications in brain trauma. J Cell Mol Med 2009; 13:262-9. [PMID: 19278456 PMCID: PMC3823353 DOI: 10.1111/j.1582-4934.2008.00508.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Accepted: 09/25/2008] [Indexed: 01/04/2023] Open
Abstract
Calponin (Cp) is an actin-binding protein first characterized in chicken gizzard smooth muscle (SM). This review discusses the role of Cp in mediating SM contraction, the biochemical process by which Cp facilitates SM contraction and the function of Cp in the brain. Recent work on the role of Cp in pathological states with emphasis on traumatic brain injury is also discussed. Based on past and present data, the case is presented for targeting Cp for novel genetic and pharmacological therapies aimed at improving outcome following traumatic brain injury (TBI).
Collapse
Affiliation(s)
- Christian W Kreipke
- Department of Anatomy and Cell Biology, Wayne State University, School of Medicine, Detroit, MI, USA
| | - Jose A Rafols
- Department of Anatomy and Cell Biology, Wayne State University, School of Medicine, Detroit, MI, USA
| |
Collapse
|
7
|
Silver B, Lu M, Morris DC, Mitsias PD, Lewandowski C, Chopp M. Blood pressure declines and less favorable outcomes in the NINDS tPA stroke study. J Neurol Sci 2008; 271:61-7. [PMID: 18455192 DOI: 10.1016/j.jns.2008.03.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 03/24/2008] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND PURPOSE Hypertension is the most important modifiable risk factor for secondary stroke prevention but the immediate management of blood pressure after stroke is uncertain. We evaluated outcomes in the NINDS tPA stroke study in relation to blood pressure declines during the first 24 h after randomization. METHODS Declines in blood pressure compared to baseline and preceding time points were analyzed in relationship to favorable outcomes (by a global test), poor outcomes (Rankin scale >3) and death at 3 months. RESULTS 551 patients did not receive immediate pre-randomization anti-hypertensive treatment and had available blood pressures. Multivariate analysis showed significantly and progressively reducing likelihoods of a favorable outcome with each 10 mmHg decline in systolic blood pressure (SBP) >50 mmHg compared to any preceding measurement. Poor outcomes were significantly more likely in patients with >50 mmHg SBP reduction (or >30 mmHg compared to any immediately preceding measurement). There was an increased risk of death with blood pressure declines >60 mmHg. tPA treatment still produced favorable outcomes compared with placebo even with blood pressure declines. The median largest SBP reduction from baseline in patients treated with tPA was 35 mmHg compared to 30 mmHg in placebo-treated patients (p<0.01). CONCLUSIONS In this post hoc analysis, progressively reducing likelihoods of a favorable outcome were seen with increasing declines in SBP. Despite a greater likelihood of favorable outcomes, tPA treatment was associated with a greater reduction in blood pressure than placebo. Randomized trials of blood pressure management are needed.
Collapse
Affiliation(s)
- Brian Silver
- Henry Ford Hospital, Detroit, MI 48202, United States.
| | | | | | | | | | | |
Collapse
|
8
|
Key role of tissue plasminogen activator in neurovascular coupling. Proc Natl Acad Sci U S A 2008; 105:1073-8. [PMID: 18195371 DOI: 10.1073/pnas.0708823105] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The increase in blood flow evoked by synaptic activity is essential for normal brain function and underlies functional brain imaging signals. Nitric oxide, a vasodilator released by NMDA receptor activation, is critical for the flow increase, but the factors linking NMDA receptor activity to nitric oxide-dependent hyperemia are poorly understood. Here, we show that tissue plasminogen activator (tPA), a serine protease implicated in NMDA receptor signaling, is required for the flow increase evoked by somatosensory stimulation. tPA acts by facilitating neuronal nitric oxide release, but this effect does not involve enhancement of NMDA currents or the associated intracellular Ca(2+) rise. Rather, the evidence suggests that tPA controls NMDA-dependent nitric oxide synthesis by influencing the phosphorylation state of neuronal nitric oxide synthase. These findings unveil a previously unrecognized role of tPA in vital homeostatic mechanisms coupling NMDA receptor signaling with nitric oxide synthesis and local cerebral perfusion.
Collapse
|
9
|
López-Atalaya JP, Roussel BD, Ali C, Maubert E, Petersen KU, Berezowski V, Cecchelli R, Orset C, Vivien D. Recombinant Desmodus rotundus salivary plasminogen activator crosses the blood-brain barrier through a low-density lipoprotein receptor-related protein-dependent mechanism without exerting neurotoxic effects. Stroke 2007; 38:1036-43. [PMID: 17325305 DOI: 10.1161/01.str.0000258100.04923.84] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Desmoteplase, a recombinant form of the plasminogen activator DSPAalpha1 from Desmodus rotundus, may offer improved clinical benefits for acute ischemic stroke treatment over the current therapy, recombinant tissue plasminogen activator (rtPA). Accumulating evidence suggests that clinical use of rtPA could be limited by unfavorable properties, including its ability to cross the blood-brain barrier (BBB), thus potentially adding to the pro-excitotoxic effect of endogenous tPA in cerebral parenchyma. Here, to investigate whether desmoteplase may display a safer profile than the structurally-related tPA, both agents were compared for their ability to cross the BBB and promote neurotoxicity. METHODS First, the passage of vascular DSPA and rtPA was investigated in vitro in a model of BBB, subjected or not to oxygen and glucose deprivation. Second, we studied DSPA- and rtPA-mediated effects in an in vivo paradigm of excitotoxic necrosis. RESULTS The rtPA and desmoteplase cross the intact BBB by LRP-mediated transcytosis. Under conditions of oxygen and glucose deprivation, translocation rates of both compounds increased; however, unlike rtPA, desmoteplase transport remained LRP-dependent. Additionally, neither intracerebral nor intravenous desmoteplase administration enhanced NMDA-induced excitotoxic striatal damage in vivo. Interestingly, intravenous but not intrastriatal coadministration of desmoteplase and rtPA reduced the pro-excitotoxic effect of rtPA. CONCLUSIONS We show that desmoteplase crosses the BBB but does not promote neuronal death. Moreover, intravenous administration of desmoteplase antagonizes the neurotoxicity induced by vascular rtPA. This action may be caused by competition of desmoteplase with rtPA for LRP binding at the BBB, thus effectively blocking rtPA access to the brain parenchyma.
Collapse
|
10
|
Armstead WM, Nassar T, Akkawi S, Smith DH, Chen XH, Cines DB, Higazi AAR. Neutralizing the neurotoxic effects of exogenous and endogenous tPA. Nat Neurosci 2006; 9:1150-5. [PMID: 16936723 DOI: 10.1038/nn1757] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Accepted: 08/03/2006] [Indexed: 11/10/2022]
Abstract
The clinical use of tissue-type plasminogen activator (tPA) in the treatment of stroke is profoundly constrained by its serious side effects. We report that the deleterious effects of tPA on cerebral edema and intracranial bleeding are separable from its fibrinolytic activity and can be neutralized. A hexapeptide (EEIIMD) corresponding to amino acids 350-355 of plasminogen activator inhibitor type 1 (PAI-1) abolished the tPA-induced increase in infarct size and intracranial bleeding in both mechanical and embolic models of stroke in rats, and reduced brain edema and neuronal loss after traumatic brain injury in pigs. These experiments suggest mechanisms to reduce the neurotoxic effects of tPA without compromising its fibrinolytic activity, through the use of selective antagonists and new tPA formulations.
Collapse
Affiliation(s)
- William M Armstead
- Department of Anesthesiology, University of Pennsylvania, 3620 Hamilton Walk, JM3, Philadelphia, Pennsylvania 19104, USA
| | | | | | | | | | | | | |
Collapse
|
11
|
Kreipke CW, Morgan NC, Petrov T, Rafols JA. Calponin and caldesmon cellular domains in reacting microvessels following traumatic brain injury. Microvasc Res 2006; 71:197-204. [PMID: 16635497 DOI: 10.1016/j.mvr.2006.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Revised: 01/11/2006] [Accepted: 02/09/2006] [Indexed: 01/16/2023]
Abstract
Calponin (Cp) and caldesmon (Cd) are actin-binding proteins involved in the regulation of smooth muscle (SM) tone during blood vessel contraction. While in vitro studies have reported modifications of these proteins during vessel contractility, their role in vivo remains unclear. Traumatic brain injury (TBI) causes disruption of cerebral microvascular tone, leading to sustained contractility in reacting microvessels and cerebral hypoperfusion. This study aimed to determine the spatial and temporal expressions of Cp and Cd in rat cerebral cortical and hippocampal microvessels post-TBI. Reacting microvessels were analyzed in control, 4, 24, and 48 h post-injury. Single and double immunocytochemical techniques together with semiquantitative analyses revealed a Cp upregulation in SM at all time frames post-TBI; with the protein migrating from SM cytosol to the vicinity of the cell membrane. Similarly, Cd immunoreactivity significantly increased in both SM and endothelial cells (En). However, while Cp and Cd in SM remained elevated, their levels in En returned to normal at 48 h post-TBI. The results suggest that Cp and Cd levels increase while compartmentalizing to specific subcellular domains. These changes are temporally associated with modifications in the cytoskeleton and contractile apparatus of SM and En during blood vessel contractility. Furthermore, these changes may underlie the state of sustained contractility and hypoperfusion observed in reacting microvessels after TBI.
Collapse
Affiliation(s)
- Christian W Kreipke
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | | | | | | |
Collapse
|
12
|
Armstead WM, Cines DB, Higazi AAR. Plasminogen Activators Contribute to Impairment of Hypercapnic and Hypotensive Cerebrovasodilation After Cerebral Hypoxia/Ischemia in the Newborn Pig. Stroke 2005; 36:2265-9. [PMID: 16141421 DOI: 10.1161/01.str.0000181078.74698.b0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
Babies are frequently exposed to hypoxia and ischemia during the perinatal period as a result of stroke or problems with delivery or respiratory management post delivery. The only U.S. Food and Drug Administration-approved treatment for acute stroke is the administration of tPA. Nonetheless, basic science studies indicate that tPA exhibits both beneficial and deleterious effects on central nervous system function. Cerebral hypoxia/ischemia (H/I) impairs dilation to hypercapnia and hypotension in the newborn pig. We investigated the role of exogenous and endogenous plasminogen activators (PA) in piglet hypercapnic and hypotensive dilator impairment after H/I.
Methods—
Responses to dilator stimuli were measured in chloralose-anesthetized piglets equipped with a closed cranial window before and after hypoxia (P
o
2
35 mm Hg) and subsequent global cerebral ischemia. Data (n=6) were analyzed by repeated-measures analysis of variance.
Results—
Hypercapnic (P
co
2
75 mm Hg) and hypotensive (mean arterial blood pressure decreased by 45%) pial artery dilation (PAD) was blunted after H/I and reversed to vasoconstriction in animals pretreated with tPA or uPA (10
−7
mol/L; 26±2, 11±1, and −4±1% for hypercapnia before, after H/I, and after H/I with tPA). In animals pretreated with EEIIMD (10
−7
mol/L), a peptide that binds uPA and tPA but does not affect proteolysis or soluble uPA receptor (suPAR, 10
−7
mol/L), which binds but does not affect the proteolytic activity of uPA. PAD induced by hypercapnia and hypotension was attenuated to a lesser extent (25±2 and 17±1% for hypercapnic PAD before and after H/I in EEIIMD-pretreated animals and 21±1 and 18±2% in suPAR-pretreated animals).
Conclusions—
These data show that exogenous PA administration potentiates the impairment of hypercapnic and hypotensive PAD that occurs after H/I. Inhibition of endogenous PA may ameliorate the impairment of PAD induced by hypercapnia and hypotension PAD that develops after hypoxic central nervous system injury of diverse etiologies.
Collapse
Affiliation(s)
- William M Armstead
- Department of Anesthesia, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | | | | |
Collapse
|
13
|
Armstead WM, Cines DB, Higazie AAR. Plasminogen activators contribute to age-dependent impairment of NMDA cerebrovasodilation after brain injury. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2005; 156:139-46. [PMID: 16099300 DOI: 10.1016/j.devbrainres.2005.02.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2004] [Revised: 02/09/2005] [Accepted: 02/10/2005] [Indexed: 12/01/2022]
Abstract
Previous studies have observed that fluid percussion brain injury (FPI) impaired NMDA induced pial artery dilation in an age-dependent manner. This study was designed to investigate the contribution of plasminogen activators to impaired NMDA dilation after FPI in newborn and juvenile pigs equipped with a closed cranial window. In the newborn pig, NMDA (10(-8), 10(-6) M) induced pial artery dilation was reversed to vasoconstriction following FPI, but pretreatment with the plasminogen activator inhibitor PAI-1 derived hexapeptide (EEIIMD) (10(-7) M) prevented post injury vasoconstriction (9 +/- 1 and 16 +/- 1, vs. -6 +/- 2 and-11 +/- 3, vs. 5 +/- 1 and 9 +/- 1% for responses to NMDA 10(-8), 10(-6) M prior to FPI, after FPI, and after FPI in EEIIMD pretreated animals, respectively). In contrast, in the juvenile pig, NMDA dilation was only attenuated following FPI and EEIIMD pretreatment partially prevented such inhibition (9 +/- 1 and 16 +/- 1 vs. 2 +/- 1 and 4 +/- 1 vs. 5 +/- 1 and 7 +/- 1% for responses to NMDA prior to FPI, after FPI, and after FPI in EEIIMD pretreated animals, respectively). Additionally, EEIIMD blunted age-dependent pial artery vasoconstriction following FPI. EEIIMD blocked dilation to the plasminogen activator agonists uPA and tPA while responses to SNP and papaverine were unchanged. Pretreatment with suPAR, which blocked dilation to uPA, elicited effects on pial artery diameter and NMDA vascular activity post FPI similar to that observed with EEIIMD. These data show that EEIIMD and suPAR partially prevented FPI induced alterations in NMDA dilation and reductions in pial artery diameter. EEIIMD and suPAR are efficacious and selective inhibitors of plasminogen activator induced dilation. These data suggest that plasminogen activators contribute to age-dependent impairment of NMDA induced dilation following FPI.
Collapse
Affiliation(s)
- William M Armstead
- Department of Anesthesia, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | | | | |
Collapse
|