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Recombinant tissue plasminogen activator enhances microglial cell recruitment after stroke in mice.

ABSTRACT: The effect of recombinant human tissue plasminogen activator (rtPA) on neuroinflammation after stroke remains largely unknown. Here, we tested the effect of rtPA on expression of cellular adhesion molecules, chemokines, and cytokines, and compared those with levels of inflammatory cell recruitment, brain injury, and mortality over 3 days after transient middle cerebral artery occlusion (MCAO) in mice. Mortality was dramatically increased after rtPA treatment compared with saline treatment during the first day of reperfusion. Among the animals that survived, rtPA significantly increased CCL3 expression, microglia recruitment, and cerebral infarction 6 hours after MCAO. In contrast, the extent of neutrophils and macrophages infiltration in the brain was similar in both saline- and rtPA-treated animals. Recombinant human tissue plasminogen activator induced Il1b and Tnf expression, 6 and 72 hours after MCAO, respectively, and dramatically reduced interleukin 6 (IL-6) level 24 hours after reperfusion. A dose response study confirmed the effect of rtPA on CCL3 and Il1b expressions. The effect was similar at the doses of 1 and 10 mg/kg. In conclusion, we report for the first time that rtPA amplified microglia recruitment early after stroke in association with a rapid CCL3 production. This early response may take part in the higher susceptibility of rtPA-treated animals to reperfusion injury.

SUBMITTER: Lenglet S

PROVIDER: S-EPMC4013777 | biostudies-literature | 2014 May

REPOSITORIES: biostudies-literature

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Recombinant tissue plasminogen activator enhances microglial cell recruitment after stroke in mice.

Lenglet Sébastien S Montecucco Fabrizio F Denes Adam A Coutts Graham G Pinteaux Emmanuel E Mach François F Schaller Karl K Gasche Yvan Y Copin Jean-Christophe JC

Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism 20140129 5

The effect of recombinant human tissue plasminogen activator (rtPA) on neuroinflammation after stroke remains largely unknown. Here, we tested the effect of rtPA on expression of cellular adhesion molecules, chemokines, and cytokines, and compared those with levels of inflammatory cell recruitment, brain injury, and mortality over 3 days after transient middle cerebral artery occlusion (MCAO) in mice. Mortality was dramatically increased after rtPA treatment compared with saline treatment during ...[more]

PMID: 24473480

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Project description:Background and Purpose- Thrombolytic treatment of acute ischemic stroke with tPA (tissue-type plasminogen activator) is hampered by its narrow therapeutic window and potential hemorrhagic complication. Vepoloxamer is a nonionic surfactant that exerts potent hemorheologic and antithrombotic properties in various thrombotic diseases. The current study investigated the effect of vepoloxamer on tPA treatment in a rat model of embolic stroke. Methods- Male Wistar rats subjected to embolic middle cerebral artery occlusion were treated with the combination of vepoloxamer and tPA, vepoloxamer alone, tPA alone, or saline initiated 4 hours after middle cerebral artery occlusion. Results- Monotherapy with tPA did not reduce infarct volume, and adversely potentiated microvascular thrombosis and vascular leakage compared with the saline treatment. Vepoloxamer monotherapy reduced infarct volume by 25% and improved brain perfusion. However, the combination treatment with vepoloxamer and tPA significantly reduced infarct volume by 32% and improved neurological function, without increasing the incidence of gross hemorrhage. Compared with vepoloxamer alone, the combination treatment with vepoloxamer and tPA robustly reduced secondary thrombosis and tPA-augmented microvascular leakage and further improved brain perfusion, which was associated with substantial reductions of serum active PAI-1 (plasminogen activator inhibitor-1) level and tPA-upregulated PAI-1 in the ischemic brain. Mechanistically, exosomes derived from platelets of ischemic rats treated with tPA-augmented cerebral endothelial barrier permeability and elevated protein levels of PAI-1 and TF (tissue factor) in the endothelial cells, whereas exosomes derived from platelets of rats subjected to the combination treatment with vepoloxamer and tPA diminished endothelial permeability augmented by tPA and fibrin and reduced PAI-1 and TF levels in the endothelial cells. Conclusions- The combination treatment with vepoloxamer and tPA exerts potent thrombolytic effects in rats subjected to acute ischemic stroke. Vepoloxamer reduces tPA-aggravated prothrombotic effect of platelet-derived exosomes on cerebral endothelial cells, which may contribute to the therapeutic effect of the combination treatment.

Project description:BACKGROUND:The necessity for rapid evaluation and treatment of acute ischemic stroke with intravenous tPA (tissue-type plasminogen activator) may increase the risk of administrating tPA to patients presenting with noncerebrovascular conditions that closely resemble stroke (stroke mimics). However, there are limited data on thrombolysis safety in stroke mimics. METHODS AND RESULTS:Using data from the Get With The Guidelines-Stroke Registry, we identified 72?582 patients with suspected ischemic stroke treated with tPA from 485 US hospitals between January 2010 and December 2017. We documented the use of tPA in stroke mimics, defined as patients who present with stroke-like symptoms, but after workup are determined not to have suffered from a stroke or transient ischemic attack, and compared characteristics and outcomes in stroke mimics versus those with ischemic stroke. Overall, 3.5% of tPA treatments were given to stroke mimics. Among them, 38.2% had a final nonstroke diagnoses of migraine, functional disorder, seizure, and electrolyte or metabolic imbalance. Compared with tPA-treated true ischemic strokes, tPA-treated mimics were younger (median 54 versus 71 years), had a less severe National Institute of Health Stroke Scale (median 6 versus 8), and a lower prevalence of cardiovascular risk factors, except for a higher prevalence of prior stroke/transient ischemic attack (31.3% versus 26.1%, all P<0.001). The rate of symptomatic intracranial hemorrhage was lower in stroke mimics (0.4%) as compared with 3.5% in ischemic strokes (adjusted odds ratio, 0.29; 95% CI, 0.17-0.50). In-hospital mortality rate was significantly lower in stroke mimics (0.8% versus 6.2%, adjusted odds ratio, 0.31; 95% CI, 0.20-0.49). Patients with stroke mimics were more likely to be discharged to home (83.8% versus 49.3%, adjusted odds ratio, 2.97; 95% CI, 2.59-3.42) and to ambulate independently at discharge (78.6% versus 50.6%, adjusted odds ratio, 1.86; 95% CI, 1.61-2.14). CONCLUSIONS:In this large cohort of patients treated with tPA, relatively few patients who received tPA for presumed stroke were ultimately not diagnosed with a stroke or transient ischemic attack. The complication rates associated with tPA in stroke mimics were low. Despite the potential risk of administering tPA to stroke mimics, opportunity remains for continued improvement in the rapid and accurate diagnosis and treatment of ischemic stroke.

Project description:BackgroundRecombinant tissue plasminogen activator (rt-PA, alteplase) improved functional outcome in patients treated soon after acute ischaemic stroke in randomised trials, but licensing is restrictive and use varies widely. The IST-3 trial adds substantial new data. We therefore assessed all the evidence from randomised trials for rt-PA in acute ischaemic stroke in an updated systematic review and meta-analysis.MethodsWe searched for randomised trials of intravenous rt-PA versus control given within 6 h of onset of acute ischaemic stroke up to March 30, 2012. We estimated summary odds ratios (ORs) and 95% CI in the primary analysis for prespecified outcomes within 7 days and at the final follow-up of all patients treated up to 6 h after stroke.FindingsIn up to 12 trials (7012 patients), rt-PA given within 6 h of stroke significantly increased the odds of being alive and independent (modified Rankin Scale, mRS 0-2) at final follow-up (1611/3483 [46·3%] vs 1434/3404 [42·1%], OR 1·17, 95% CI 1·06-1·29; p=0·001), absolute increase of 42 (19-66) per 1000 people treated, and favourable outcome (mRS 0-1) absolute increase of 55 (95% CI 33-77) per 1000. The benefit of rt-PA was greatest in patients treated within 3 h (mRS 0-2, 365/896 [40·7%] vs 280/883 [31·7%], 1·53, 1·26-1·86, p<0·0001), absolute benefit of 90 (46-135) per 1000 people treated, and mRS 0-1 (283/896 [31·6%] vs 202/883 [22·9%], 1·61, 1·30-1·90; p<0·0001), absolute benefit 87 (46-128) per 1000 treated. Numbers of deaths within 7 days were increased (250/2807 [8·9%] vs 174/2728 [6·4%], 1·44, 1·18-1·76; p=0·0003), but by final follow-up the excess was no longer significant (679/3548 [19·1%] vs 640/3464 [18·5%], 1·06, 0·94-1·20; p=0·33). Symptomatic intracranial haemorrhage (272/3548 [7·7%] vs 63/3463 [1·8%], 3·72, 2·98-4·64; p<0·0001) accounted for most of the early excess deaths. Patients older than 80 years achieved similar benefit to those aged 80 years or younger, particularly when treated early.InterpretationThe evidence indicates that intravenous rt-PA increased the proportion of patients who were alive with favourable outcome and alive and independent at final follow-up. The data strengthen previous evidence to treat patients as early as possible after acute ischaemic stroke, although some patients might benefit up to 6 h after stroke.FundingUK Medical Research Council, Stroke Association, University of Edinburgh, National Health Service Health Technology Assessment Programme, Swedish Heart-Lung Fund, AFA Insurances Stockholm (Arbetsmarknadens Partners Forsakringsbolag), Karolinska Institute, Marianne and Marcus Wallenberg Foundation, Research Council of Norway, Oslo University Hospital.

Dataset Information

Recombinant tissue plasminogen activator enhances microglial cell recruitment after stroke in mice.

Publications

Recombinant tissue plasminogen activator enhances microglial cell recruitment after stroke in mice.

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