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[Background] Thrombolytic recombinant tissue plasminogen activator (r-tPA) treatment is the only pharmacologic intervention available in the ischemic stroke acute phase. This treatment is associated with an increased risk of intracerebral hemorrhages, known as hemorrhagic transformations (HTs), which worsen the patient’s prognosis., [Objectives] To investigate the association between genetically determined natural hemostatic factors’ levels and increased risk of HT after r-tPA treatment., [Methods] Using data from genome-wide association studies on the risk of HT after r-tPA treatment and data on 7 hemostatic factors (factor [F]VII, FVIII, von Willebrand factor [VWF], FXI, fibrinogen, plasminogen activator inhibitor-1, and tissue plasminogen activator), we performed local and global genetic correlation estimation multitrait analyses and colocalization and 2-sample Mendelian randomization analyses between hemostatic factors and HT., [Results] Local correlations identified a genomic region on chromosome 16 with shared covariance: fibrinogen-HT, P = 2.45 × 10−11. Multitrait analysis between fibrinogen-HT revealed 3 loci that simultaneously regulate circulating levels of fibrinogen and risk of HT: rs56026866 (PLXND1), P = 8.80 × 10−10; rs1421067 (CHD9), P = 1.81 × 10−14; and rs34780449, near ROBO1 gene, P = 1.64 × 10−8. Multitrait analysis between VWF-HT showed a novel common association regulating VWF and risk of HT after r-tPA at rs10942300 (ZNF366), P = 1.81 × 10−14. Mendelian randomization analysis did not find significant causal associations, although a nominal association was observed for FXI-HT (inverse-variance weighted estimate [SE], 0.07 [−0.29 to 0.00]; odds ratio, 0.87; 95% CI, 0.75-1.00; raw P = .05)., [Conclusion] We identified 4 shared loci between hemostatic factors and HT after r-tPA treatment, suggesting common regulatory mechanisms between fibrinogen and VWF levels and HT. Further research to determine a possible mediating effect of fibrinogen on HT risk is needed.

[Abstract] Background: Thrombolytic recombinant tissue plasminogen activator (r-tPA) treatment is the only pharmacologic intervention available in the ischemic stroke acute phase. This treatment is associated with an increased risk of intracerebral hemorrhages, known as hemorrhagic transformations (HTs), which worsen the patient's prognosis. Objectives: To investigate the association between genetically determined natural hemostatic factors' levels and increased risk of HT after r-tPA treatment. Methods: Using data from genome-wide association studies on the risk of HT after r-tPA treatment and data on 7 hemostatic factors (factor [F]VII, FVIII, von Willebrand factor [VWF], FXI, fibrinogen, plasminogen activator inhibitor-1, and tissue plasminogen activator), we performed local and global genetic correlation estimation multitrait analyses and colocalization and 2-sample Mendelian randomization analyses between hemostatic factors and HT. Results: Local correlations identified a genomic region on chromosome 16 with shared covariance: fibrinogen-HT, P = 2.45 × 10-11. Multitrait analysis between fibrinogen-HT revealed 3 loci that simultaneously regulate circulating levels of fibrinogen and risk of HT: rs56026866 (PLXND1), P = 8.80 × 10-10; rs1421067 (CHD9), P = 1.81 × 10-14; and rs34780449, near ROBO1 gene, P = 1.64 × 10-8. Multitrait analysis between VWF-HT showed a novel common association regulating VWF and risk of HT after r-tPA at rs10942300 (ZNF366), P = 1.81 × 10-14. Mendelian randomization analysis did not find significant causal associations, although a nominal association was observed for FXI-HT (inverse-variance weighted estimate [SE], 0.07 [-0.29 to 0.00]; odds ratio, 0.87; 95% CI, 0.75-1.00; raw P = .05). Conclusion: We identified 4 shared loci between hemostatic factors and HT after r-tPA treatment, suggesting common regulatory mechanisms between fibrinogen and VWF levels and HT. Further research to determine a possible mediating effect of fibrinogen on HT

Cerebral edema (CED) is a common complication of ischemic stroke in Intensive Care Unit. Although frequently observed in patients undergoing intravenous thrombolytic (IVT) treatment, the pathogenic role of recombinant tissue plasminogen activator (rtPA) in CED induction has not yet been definitively clarified. The aim of our study is to verify the relationship between CED and rtPA in patients affected by acute ischemic stroke, without reperfusion signs, evaluating the CED growth rate in the first week after stroke onset. In this single-center, retrospective observational study, we included all consecutive patients with acute stroke undergone multi parameter monitoring of vital signs in the sub-intensive care Unit. We included both patients undergoing systemic IVT and standard medical treatment (n-IVT) with the following time of CT scan: within 4.5 h onset, 24 +/- 12 h, 72 +/- 24 h and 120 +/- 24 h from the stroke onset. Of 1753 with acute ischemic stroke patients screened, 810 patients were included in the study (218 IVT and 592 n-IVT). No significant difference was observed at baseline in age, gender, NIHSS score or infarcted area, while hemorrhagic transformation rate was significantly higher in IVT than in n-IVT group. We observed a significant increase of CED growth rate in IVT patients compared to nIVT patients only between 24 and 72 h from the ischemic event (respectively 1.85cm(3)/h and 0.89cm(3)/h; p = 0.031) regardless of the presence of HT. No significant difference was observed in growth rate between 3 and 5 days following rtPA administration or in overall growth rate. Although the pathogenetic mechanism of rtPA determining CED remains uncertain, our data suggests rtPA can act as a "trigger " of edema onset and progression. Therefore, drugs interfering with specific molecular pathways, such as kallikrein-kinin cascade, could constitute an effective strategy to reduce the risk of development and progression of rtPA-related cerebral edema in patients with a

Ishemijski moždani udar (IMU) nastaje usled okluzije krvnog suda embolusom, ili trombozom in situ u određenim regionima mozga. Centralna zona ishemije, sa terapijskog aspekta, od početka je izgubljena, ali oko nje se nalazi zona penumbre u kojoj su neuroni poremećene funkcije, ali strukturalno intaktni i gde je još uvek moguć oporavak njihove funkcije. Terapija izbora u akutnoj fazi IMU je intravenska primena rekombinovanog tkivnog aktivatora plazminogena (rtPA). Uprkos činjenici da samo mali broj pacijenata sa akutnim IMU primi rtPA, pacijenati u terapijskom prozoru za primenu iste, imaju veće dugoročno preživljavanje i niže stope mortaliteta, kao i bolji funkcionalni oporavak nakon IMU. Sa druge strane, kod određenog broja pacijenata koji su primili rtPA, dolazi do hemoragijske transformcije (HT) ili simptomatske intrakranijalne hemoragije (sICH), najozbiljnijih komplikacija ove terapije povezanih sa visokom stopom morbiditeta i mortaliteta. Razlozi zašto neki pacijenti bolje, a drugi lošije odgovore na rtPA terapiju su brojni, ali i dalje nisu do kraja razjašnjeni. Genski polimorfizmi mogu biti u osnovi različitog nivoa ekspresije gena, ili aktivnosti genskog produkta, pa posredno mogu uticati na fiziologiju i funkcionalnost ćelija, ali i na odgovor na primenjenu terapiju. Cilj ove disertacije bio je da se kod osoba sa IMU lečenim rtPA terapijom utvrdi učestalost genotipova i alela izabranih polimorfizama u genima koji regulišu fibrinolizu (PAI-1 i ACE) i intergritet vanćelijskog matriksa (MMP-2, MMP-9 i TIMP-2), kao i da se analizira povezanost ispitivanih polimorfnih genskih varijanti sa efikasnošću i pojavom hemoragijskih komplikacija nakon rtPA terapije. Metod: Istraživanje je sprovedeno po tipu hibridne panel studije. Studija je sprovedena od avgusta 2016. godine do avgusta 2018. godine u Specijalnoj bolnici za cerebrovaskularne bolesti ,,Sveti Sava’’ u Beogradu, dok su molekularno-genetička istraživanja obavljena na Institutu za humanu genetiku Medicinskog, Ischemic stroke (IS) occurs due to an embolus or thrombosis causing vascular occlusion in situ in certain brain parts. From the therapeutic point of view, the central zone of ischemia is irrelevant, since nerve cells cannot be saved. However, it is surrounded by a penumbra, an area where the neurons are functionally disturbed, but structurally intact, with the possibility for the recovery of their function. The therapy of choice in the acute phase of IS is an intravenous administration of recombined tissue plasminogen activator (rtPA). Even though only a small number of patients with acute IS receive rtPA, patients within the therapeutic window for its application have higher long-term survival and lower mortality rates, as well as better functional recovery. On the other hand, a certain number of patients who have received rtPA develop symptomatic intracranial hemorrhage (sICH) or hemorrhagic transformation (HT), as the most severe complications of this therapy - associated with high morbidity and mortality rates. The reasons why some patients respond to rtPA therapy better, and others worse are numerous, but still not fully elucidated. Gene polymorphisms could have different effects on gene expression, or the activity of a gene product, and can indirectly affect the physiology and functionality of cells, and also the response to applied therapy. This study aimed to determine the frequency of genotypes and alleles of selected polymorphisms in genes that regulate fibrinolysis (PAI-1 and ACE) and extracellular matrix integrity (MMP-2, MMP-9, and TIMP-2) in individuals with IS treated with rtPA therapy, as well as to analyze the association of the studied polymorphic gene variants with the rtPA efficacy and occurrence of hemorrhagic complications after rtPA therapy. Method: This is a hybrid panel study. It was conducted from August 2016 to August 2018 at the Special Hospital for Cerebrovascular Diseases "St. Sava" in Belgrade, while molecular genetic researches were p

Blood-brain barrier (BBB) dysfunction underlies the pathogenesis of many neurological diseases. Platelet-derived growth factor receptor-alpha (PDGFR alpha) induces hemorrhagic transformation (HT) downstream of tissue plasminogen activator in thrombolytic therapy of acute stroke. Thus, PDGFs are attractive therapeutic targets for BBB dysfunction. In the present study, we examined the role of PDGF signaling in the process of tissue remodeling after middle cerebral arterial occlusion (MCAO) in mice. Firstly, we found that imatinib increased lesion size after permanent MCAO in wild-type mice. Moreover, imatinib-induced HT only when administrated in the subacute phase of MCAO, but not in the acute phase. Secondly, we generated genetically mutated mice (C-KO mice) that showed decreased expression of perivascular PDGFR alpha. Additionally, transient MCAO experiments were performed in these mice. We found that the ischemic lesion size was not affected; however, the recruitment of PDGFR alpha/type I collagen-expressing perivascular cells was significantly downregulated, and HT and IgG leakage was augmented only in the subacute phase of stroke in C-KO mice. In both experiments, we found that the expression of tight junction proteins and PDGFR beta-expressing pericyte coverage was not significantly affected in imatinib-treated mice and in C-KO mice. The specific implication of PDGFR alpha signaling was suggestive of protective effects against BBB dysfunction during the subacute phase of stroke. Vascular TGF-beta 1 expression was downregulated in both imatinib-treated and C-KO mice, along with sustained levels of MMP9. Therefore, PDGFR alpha effects may be mediated by TGF-beta 1 which exerts potent protective effects in the BBB.

Stroke is the second leading cause of death worldwide, estimated that one-sixth of the world population will suffer it once in their life. The most common type of this medical condition is the ischemic stroke (IS), produced by a thrombotic or embolic occlusion of a major cerebral artery or its branches, leading to the formation of a complex infarct region caused by oxidative stress, excitotoxicity, and endothelial dysfunction. Nowadays, the immediate treatment for IS involves thrombolytic agents or mechanical thrombectomy, depending on the integrity of the blood-brain barrier (BBB). A common stroke complication is the hemorrhagic transformation (HT), which consists of bleeding into the ischemic brain area. Currently, better treatments for IS are urgently needed. As such, the neurohormone melatonin has been proposed as a good candidate due to its antioxidant, anti-inflammatory, and neuroprotective effects, particularly against lipid peroxidation and oxidative stress during brain ischemia. Here, we proposed to develop intravenous or intranasal melatonin nanoformulation to specifically target the brain in patients with stroke. Nowadays, the challenge is to find a formulation able to cross the barriers and reach the target organ in an effective dose to generate the pharmacological effect. In this review, we discuss the current literature about stroke pathophysiology, melatonin properties, and its potential use in nanoformulations as a novel therapeutic approach for ischemic stroke.

Recombinant tissue-plasminogen activator (rtPA) is the only drug used during the acute phase of stroke. Despite its important benefits, a percentage of patients suffer symptomatic hemorrhagic transformations or a lack of early recanalization rates. These undesirable effects are associated with acute neurological and long-term functional deterioration. For the past 20 years, pharmacogenetic studies have tried to find the genetic risk factors associated with rtPA response. Most of these studies have used a gene-candidate strategy; however, recent genome-wide association studies have emerged indicating that genetic predisposition could modulate rtPA response. This review summarizes the most interesting findings in this field, including which genes and genetic variations are associated with hemorrhagic transformations and recanalization rates after thrombolytic therapy.

One quarter to one third of patients eligible for systemic thrombolysis are on antiplatelet therapy at presentation. In this study, we aimed to assess the safety and efficacy of intravenous thrombolysis in stroke patients on prescribed antiplatelet therapy in the WAKE-UP trial. WAKE-UP was a multicenter, randomized, double-blind, placebo-controlled clinical trial to study the efficacy and safety of MRI-guided intravenous thrombolysis with alteplase in patients with an acute stroke of unknown onset time. The medication history of all patients randomized in the WAKE-UP trial was documented. The primary safety outcome was any sign of hemorrhagic transformation on follow-up MRI. The primary efficacy outcome was favorable functional outcome defined by a score of 0-1 on the modified Rankin scale at 90 days after stroke, adjusted for age and baseline stroke severity. Logistic regression models were fitted to study the association of prior antiplatelet treatment with outcome and treatment effect of intravenous alteplase. Of 503 randomized patients, 164 (32.6%) were on antiplatelet treatment. Patients on antiplatelet treatment were older (70.3 vs. 62.8 years, < 0.001), and more frequently had a history of hypertension, atrial fibrillation, diabetes, hypercholesterolemia, and previous stroke or transient ischaemic attack. Rates of symptomatic intracranial hemorrhage and hemorrhagic transformation on follow-up imaging did not differ between patients with and without antiplatelet treatment. Patients on prior antiplatelet treatment were less likely to achieve a favorable outcome (37.3% vs. 52.6%, = 0.014), but there was no interaction of prior antiplatelet treatment with intravenous alteplase concerning favorable outcome ( = 0.355). Intravenous alteplase was associated with higher rates of favorable outcome in patients on prior antiplatelet treatment with an adjusted odds ratio of 2.106 (95% CI 1.047-4.236). Treatment benefit of intravenous alteplase and rates of post-treatme

Globally, stroke is the leading cause of disability and the second leading cause of death. Management of ischemic stroke involves rapid administration of thrombolytic therapy (clot dissolving medication) for eligible patients, acute stroke unit care, and rehabilitation therapy to improve function. Pedalling using a stationary exercise bicycle is a safe and effective lower limb rehabilitation strategy in stroke patients that is known to improve aerobic capacity; however, the repetitive nature of pedalling is associated with poor motivation and exercise adherence as well as lack of perceived self-efficacy. Audio-visual engagement and feedback during exercise therapy has been shown to improve satisfaction and adherence; however, little is known about the effect of active visual engagement on exercise performance during pedalling. This thesis proposed an exercise monitoring study in healthy people and stroke patients employing a custom pedalling mechanism that monitored the exercise, provided immediate feedback on pedalling performance, and facilitated engagement through the use of video. The study involved six sessions of pedalling at a set low, and high-speed under exercise feedback and video-based engagement conditions. Heart rate (HR) and blood oxygen saturation (SpO2), as well as pedalling speed deviations, were recorded during the study. Healthy subjects demonstrated improvement in pedalling performance and reduction in exercise-induced changes in HR and SpO2 while pedalling with feedback and engagement. In contrast, stroke patients showed a significant improvement in pedalling performance only. The findings may be useful in prescription of pedalling exercises for rehabilitation, and in improving exercise compliance. Intravenous recombinant tissue plasminogen activator (rt-PA) thrombolysis treatment remains the only FDA approved therapy for acute ischemic stroke, but is associated with symptomatic intracerebral haemorrhage (SICH). Since administration of thromboly

Background Follow-up infarct volume (FIV) has been recommended as an early indicator of treatment efficacy in patients with acute ischemic stroke. Questions remain about the optimal imaging approach for FIV measurement. Objective To examine the association of FIV with 90-day modified Rankin Scale (mRS) score and investigate its dependency on acquisition time and modality. Methods Data of seven trials were pooled. FIV was assessed on follow-up (12 hours to 2 weeks) CT or MRI. Infarct location was defined as laterality and involvement of the Alberta Stroke Program Early CT Score regions. Relative quality and strength of multivariable regression models of the association between FIV and functional outcome were assessed. Dependency of imaging modality and acquisition time (48 hours) was evaluated. Results Of 1665 included patients, 83% were imaged with CT. Median FIV was 41 mL (IQR 14-120). A large FIV was associated with worse functional outcome (OR=0.88(95% CI 0.87 to 0.89) per 10 mL) in adjusted analysis. A model including FIV, location, and hemorrhage type best predicted mRS score. FIV of >= 133 mL was highly specific for unfavorable outcome. FIV was equally strongly associated with mRS score for assessment on CT and MRI, even though large differences in volume were present (48 mL (IQR 15-131) vs 22 mL (IQR 8-71), respectively). Associations of both early and late FIV assessments with outcome were similar in strength (rho=0.60(95% CI 0.56 to 0.64) and rho=0.55(95% CI 0.50 to 0.60), respectively). Conclusions In patients with an acute ischemic stroke due to a proximal intracranial occlusion of the anterior circulation, FIV is a strong independent predictor of functional outcome and can be assessed before 48 hours, oneither CT or MRI.

Numerous studies have documented increases in matrix metalloproteinases (MMPs), specifically MMP-9 levels following stroke, with such perturbations associated with disruption of the blood brain barrier (BBB), increased risk of hemorrhagic complications, and worsened outcome. Despite this, controversy remains as to which cells release MMP-9 at the normal and pathological BBB, with even less clarity in the context of stroke. This may be further complicated by the influence of tissue plasminogen activator (tPA) treatment. The aim of the present review is to examine the relationship between neutrophils, MMP-9 and tPA following ischemic stroke to elucidate which cells are responsible for the increases in MMP-9 and resultant barrier changes and hemorrhage observed following stroke.

Numerous studies have documented increases in matrix metalloproteinases (MMPs), specifically MMP-9 levels following stroke, with such perturbations associated with disruption of the blood brain barrier (BBB), increased risk of hemorrhagic complications, and worsened outcome. Despite this, controversy remains as to which cells release MMP-9 at the normal and pathological BBB, with even less clarity in the context of stroke. This may be further complicated by the influence of tissue plasminogen activator (tPA) treatment. The aim of the present review is to examine the relationship between neutrophils, MMP-9 and tPA following ischemic stroke to elucidate which cells are responsible for the increases in MMP-9 and resultant barrier changes and hemorrhage observed following stroke.

The purpose of this study was to investigate the relationship between hyperperfusion and hemorrhagic transformation (HT) in acute ischemic stroke (AIS). Pseudo-continuous arterial spin labeling (ASL) with background suppressed 3D GRASE was performed during routine clinical magnetic resonance imaging (MRI) on AIS patients at various time points. Arterial spin labeling cerebral blood flow (CBF) maps were visually inspected for the presence of hyperperfusion. Hemorrhagic transformation was followed during hospitalization and was graded on gradient recalled echo (GRE) scans into hemorrhagic infarction (HI) and parenchymal hematoma (PH). A total of 361 ASL scans were collected from 221 consecutive patients with middle cerebral artery stroke from May 2010 to September 2013. Hyperperfusion was more frequently detected posttreatment (odds ratio (OR) = 4.8, 95% confidence interval (CI) 2.5 to 8.9, P < 0.001) and with high National Institutes of Health Stroke Scale (NIHSS) scores at admission (P<0.001). There was a significant association between having hyperperfusion at any time point and HT (OR = 3.5, 95% CI 2.0 to 6.3, P < 0.001). There was a positive relationship between the grade of HT and time-hyperperfusion with the Spearman's rank correlation of 0.44 (P = 0.003). Arterial spin labeling hyperperfusion may provide an imaging marker of HT, which may guide the management of AIS patients post tissue-type plasminogen activator (tPA) and/or endovascular treatments. Late hyperperfusion should be given more attention to prevent high-grade HT.

The purpose of this study was to investigate the relationship between hyperperfusion and hemorrhagic transformation (HT) in acute ischemic stroke (AIS). Pseudo-continuous arterial spin labeling (ASL) with background suppressed 3D GRASE was performed during routine clinical magnetic resonance imaging (MRI) on AIS patients at various time points. Arterial spin labeling cerebral blood flow (CBF) maps were visually inspected for the presence of hyperperfusion. Hemorrhagic transformation was followed during hospitalization and was graded on gradient recalled echo (GRE) scans into hemorrhagic infarction (HI) and parenchymal hematoma (PH). A total of 361 ASL scans were collected from 221 consecutive patients with middle cerebral artery stroke from May 2010 to September 2013. Hyperperfusion was more frequently detected posttreatment (odds ratio (OR) = 4.8, 95% confidence interval (CI) 2.5 to 8.9, P < 0.001) and with high National Institutes of Health Stroke Scale (NIHSS) scores at admission (P<0.001). There was a significant association between having hyperperfusion at any time point and HT (OR = 3.5, 95% CI 2.0 to 6.3, P < 0.001). There was a positive relationship between the grade of HT and time-hyperperfusion with the Spearman's rank correlation of 0.44 (P = 0.003). Arterial spin labeling hyperperfusion may provide an imaging marker of HT, which may guide the management of AIS patients post tissue-type plasminogen activator (tPA) and/or endovascular treatments. Late hyperperfusion should be given more attention to prevent high-grade HT.

Acute ischemic stroke is caused by a blocked blood vessel in the cerebral circulation. It is the most common form of stroke worldwide and a major cause of disability and death. Treatments to re-open the blocked blood vessel and reperfuse the brain are available but their effectiveness, when applied to all patients, rapidly decreases over the first few hours after stroke onset. However, there is significant pathophysiological heterogeneity within acute stroke patients which can be revealed using advanced MRI and CT techniques. The principle of “ischemic penumbra” – hypoperfused and often non-functioning brain that will, nonetheless, potentially recover if reperfused – underlies all therapies aiming to restore blood flow in acute ischemic stroke. Perfusion-diffusion mismatch using MRI is a surrogate marker of ischemic penumbra that has been refined over the last decade. This thesis examines the validity of the mismatch paradigm and confirms the use of diffusion imaging as a reliable indicator of irreversibly damaged brain. Diffusion imaging at 24 hours (a commonly used timepoint to assess reperfusion and hemorrhage) is also established as an accurate measure of final infarct volume. This allows calculation of infarct growth as a surrogate outcome whilst minimising loss to follow-up and is a strong predictor of clinical recovery. A less predictable outcome is the proportion of hypoperfused brain that will proceed to infarction in the absence of reperfusion. Collateral blood flow is shown to be a dynamic phenomenon with alterations correlating with infarct growth. The relationship between collateral flow and perfusion-diffusion mismatch is explored. The mismatch paradigm is then translated to CT perfusion which is more widely accessible in most centres but has, until recently, lacked thorough validation. Perfusion thresholds such as Tmax>6sec translate directly to CT. The best correlate of diffusion imaging for infarct core is shown to be relative cerebral blood flow (r

The effectiveness and complications of endovascular thrombectomy were analyzed. The obtained results show the reduction in mortality and disability among the patients after endovascular treatment