Platelet derived growth factor-CC isoform is associated with hemorrhagic transformation in ischemic stroke patients treated with tissue plasminogen activator.

OBJECTIVE: Platelet derived growth factor-CC (PDGF-CC) isoform is activated by tissue plasminogen activator (tPA) regulating blood brain barrier permeability after ischemia. We aimed to study the association of PDGF isoforms serum levels with hemorrhagic transformation (HT) and edema after thrombolytic treatment in ischemic stroke. METHODS: We studied 129 patients with ischemic stroke treated with tPA within the first 4.5 h (h) from stroke onset. CT was performed on admission and at 24-36 h. On the 2nd CT, HT was classified according to ECASS II criteria, and severe brain edema was diagnosed if extensive swelling causing any shifting of the structures of the midline was detected. PDGF-AA, PDGF-AB, PDGF-BB and PDGF-CC serum levels were analyzed by ELISA on admission (before tPA bolus), at 24 and 72 h. RESULTS: Patients who developed HT showed only higher levels of PDGF-CC isoform on admission and at 24 h (all p < 0.0001). In the multivariate analysis, PDGF-CC levels on admission (OR, 1.02; CI 95%, 1.00-1.04) and at 24 h (OR, 1.05; CI 95%, 1.02-1.08) were independently associated with HT after adjustment by confounding factors. On the other hand, patients with severe edema showed also higher levels of PDGF-CC on admission and at 24 h (p < 0.0001), but this statistical association was lost in the logistic regression analysis. PDGF-CC levels ≥ 175 ng/mL at 24 h predict the development of PH with a sensitivity of 90% and specificity of 88% (area under the curve 0.936; p < 0.0001). CONCLUSION: Increased PDGF-CC levels after tPA treatment is associated with HT.

Neuroprotection afforded by antagonists of endothelin-1 receptors in experimental stroke.

Endothelin-1 (ET-1) is involved on the development of cerebral edema in acute ischemic stroke. As edema is a therapeutic target in cerebral ischemia, our aim was to study the effect of antagonists for ET-1 receptors (Clazosentan® and BQ-788, specific antagonists for receptors A and B, respectively) on the development of edema, infarct volume and sensorial-motor deficits in rats subjected to ischemia by occlusion of the middle cerebral artery (MCAO). We used Wistar rats (280-320 g) submitted to ischemia by intraluminal transient (90 min) MCAO. After ischemia, rats were randomized into 4 groups (n = 6) treated with; 1) control group (saline), 2) Clazosentan® group (10 mg/kg iv), 3) BQ-788 group (3 mg/kg iv), and 4) combined treatment (Clazosentan® 10 mg/kg plus BQ-788 3 mg/kg iv). We observed that rats treated with Clazosentan® showed a reduction of edema, measured by MRI, at 72 h (hours) and at day 7 (both p < 0.0001), and a decrease in the serum levels of ET-1 at 72 h (p < 0.0001) and at day 7 (p = 0.009). The combined treatment also induced a reduction of edema at 24 h (p = 0.004), 72 h (p < 0.0001) and at day 7 (p < 0.0001), a reduction on infarct volume, measured by MRI, at 24 and 72 h, and at day 7 (all p < 0.01), and a better sensorimotor recovery at 24 and 72 h, and at day 7 (all p < 0.01). Moreover, Clazosentan® induced a decrease in AQP4 expression, while BQ-788 induced an increase in AQP9 expression. These results suggest that antagonists for ET-1 receptors may be a good therapeutic target for cerebral ischemia.

A higher body temperature is associated with haemorrhagic transformation in patients with acute stroke untreated with recombinant tissue-type plasminogen activator (rtPA).

Higher body temperature is a prognostic factor of poor outcome in acute stroke. Our aim was to study the relationship between body temperature, HT (haemorrhagic transformation) and biomarkers of BBB (blood-brain barrier) damage in patients with acute ischaemic stroke untreated with rtPA (recombinant tissue-type plasminogen activator). We studied 229 patients with ischaemic stroke <12 h from symptom onset. Body temperature was determined at admission and every 6 h during the first 3 days. HT was evaluated according to ECASS II (second European Co-operative Acute Stroke Study) criteria in a multimodal MRI (magnetic resonance imaging) at 72 h. We found that 55 patients (34.1%) showed HT. HT was associated with cardioembolic stroke (64.2% against 23.0%; P<0.0001), higher body temperature during the first 24 h (36.9°C compared with 36.5°C; P<0.0001), more severe stroke [NIHSS (National Institutes of Health Stroke Scale) score, 14 (9-20) against 10 (7-15); P=0.002], and greater DWI (diffusion-weighted imaging) lesion volume at admission (23.2 cc compared with 13.2 cc; P<0.0001). Plasma MMP-9 (matrix metalloproteinase 9) (187.3 ng/ml compared with 44.2 ng/ml; P<0.0001) and cFn (cellular fibronectin) levels (16.3 µg/ml compared with 7.1 µg/ml; P=0.001) were higher in patients with HT. Body temperature within the first 24 h was independently associated with HT {OR (odds ratio), 7.3 [95% CI (confidence interval), 2.4-22.6]; P<0.0001} after adjustment for cardioembolic stroke subtype, baseline NIHSS score and DWI lesion volume. This effect remained unchanged after controlling for MMP-9 and cFn. In conclusion, high body temperature within the first 24 h after ischaemic stroke is a risk factor for HT in patients untreated with rtPA. This effect is independent of some biological signatures of BBB damage.

Association between neuroserpin and molecular markers of brain damage in patients with acute ischemic stroke.

BACKGROUND: Neuroserpin has shown neuroprotective effects in animal models of cerebral ischemia and has been associated with functional outcome after ischemic stroke. Our aim was to study whether neuroserpin serum levels could be associated to biomarkers of excitotoxicity, inflammation and blood brain barrier disruption. METHODS: We prospectively included 129 patients with ischemic stroke (58.1% male; mean age, 72.4 ± 9.6 years) not treated with tPA within 12 hours (h) of symptoms onset (mean time, 4.7 ± 2.1 h). Poor functional outcome at 3 months was considered as a modified Rankin scale score >2. Serum levels of neuroserpin, Interleukin 6 (IL-6), Intercellular adhesion molecule-1 (ICAM-1), active Matrix metalloproteinase 9 (MMP-9), and cellular fibronectin (cFn) (determined by ELISA) and glutamate (determined by HPLC) were measured on admission, 24 and 72 h. The main variable was considered the decrease of neuroserpin levels within the first 24 h. ROC analysis was used to select the best predictive value for neuroserpin to predict poor functional outcome due to a lack of linearity. RESULTS: The decrease of neuroserpin levels within the first 24 h was negatively correlated with serum levels at 24 hours of glutamate (r = -0.642), IL-6 (r = -0.678), ICAM-1 (r = -0.345), MMP-9 (r = -0.554) and cFn (r = -0.703) (all P < 0.0001). In the multivariate analysis, serum levels of glutamate (OR, 1.04; CI95%, 1.01-1.06, p = 0.001); IL-6 (OR, 1.4; CI95%, 1.1-1.7, p = 0.001); and cFn (OR, 1.3; CI95%, 1.1-1.6, p = 0.002) were independently associated with a decrease of neuroserpin levels <70 ng/mL at 24 h after adjusting for confounding factors. CONCLUSIONS: These findings suggest that neuroprotective properties of neuroserpin may be related to the inhibition of excitotoxicity, inflammation, as well as blood brain barrier disruption that occur after acute ischemic stroke.

Toll-like receptors 2 and 4 in ischemic stroke: outcome and therapeutic values.

Stroke triggers an intense inflammatory response that could be a consequence of Toll-like receptors (TLRs) activation. However, the clinical significance and the therapeutic possibilities of TLR in stroke is not completely clear. In this study, we analyze the association between the expression of TLR2 and TLR4, inflammatory molecules and endogenous ligands, and clinical outcome of ischemic stroke patients, and we test the potential of TLR2/TLR4 and their endogenous ligands as therapeutic targets. For this purpose, we included 110 patients with ischemic stroke finding that TLR2 and TLR4 are independently associated to poor outcome and correlated with higher serum levels of interleukin (IL)1ß, IL6, tumor necrosis factor α, and VCAM1, and that TLR4 was independently associated to lesion volume. In addition, we have developed an in vitro model to test the potential therapeutic value of blocking TLR2/TLR4 or their endogenous ligands. Cultured cells (monocytes and human umbilical vein endothelial cells) were treated with serum from ischemic stroke patients, showing a strong inflammatory response that was blocked when TLR2/4 or cellular fibronectin (cFN) or HSP60 were blocked. In conclusion, TLR2 and TLR4 are associated to outcome in stroke patients and TLR2/4 or their endogenous ligands, cFN/HSP60 could be new therapeutic targets for ischemic stroke.

Temporal profile and clinical significance of serum neuron-specific enolase and S100 in ischemic and hemorrhagic stroke.

BACKGROUND: Neuron-specific enolase (NSE) and S100 protein are implicated in several brain injuries, including stroke. Our objective was to analyze the temporal profile and the clinical significance of NSE and S-100 in acute ischemic (IS) and intracerebral hemorrhage (ICH). METHODS: We studied 224 patients with IS and 44 patients with ICH. Computerized tomography (CT) scans were performed to assess infarct volume. Stroke severity was evaluated using the National Institute of Health Stroke Scale (NIHSS), and functional outcome at 3 months with the modified Rankin Scale (mRS). Serum NSE and S100 protein were measured using an electrochemiluminescence-immunoassay. RESULTS: Peak values were found at 72 h for NSE and at 24 h for S100 in IS. For ICH, peak values were found at 24 h for both NSE and S100. At these time intervals S100 and NSE correlated with the NIHSS score and were independently associated with poor outcome. CONCLUSIONS: High serum NSE and S100 are associated with poor outcome in IS, and high serum NSE is associated with poor outcome in ICH. These findings suggest the potential utility of NSE and S100 as prognostic markers for acute stroke.

High serum levels of endothelin-1 predict severe cerebral edema in patients with acute ischemic stroke treated with t-PA.

BACKGROUND AND PURPOSE: Severe cerebral edema is associated with poor outcome in patients with acute stroke. Experimental studies suggest that astrocytic endothelin-1 (ET-1) has deleterious effects on water homeostasis, cerebral edema, and blood brain barrier (BBB) integrity, which contribute to more severe ischemic brain injury. In this study we analyze the association between high serum levels of ET-1 and the development of severe cerebral edema in patients treated with t-PA. METHODS: One hundred thirty-four patients treated with t-PA according SITS-MOST (Safe Implementation of Thrombolysis in Stroke Monitoring Study) criteria were prospectively studied. Serum levels of ET-1, matrix metalloproteinase-9 (MMP-9), and cellular fibronectin (c-Fn) were determined by ELISA in serum samples obtained on admission, before t-PA bolus. Severe brain edema was diagnosed if extensive swelling caused any shifting of the structures of the midline was detected on the cranial CT performed at 24 to 36 hours. Stroke severity was evaluated before t-PA administration and at 24 hours by NIHSS. Functional outcome at 3 months was evaluated by the modified Rankin Scale (mRS). RESULTS: Nineteen patients (14.2%) developed severe brain edema. Median ET-1 (8.4 [6.7, 9.6] versus 1.9 [1.6, 3.2] fmol/mL, P<0.0001) and c-Fn (6.0 [4.1, 6.7] versus 3.2 [2.1, 4.6] mg/L, P<0.0001) serum levels were significantly higher in patients with severe cerebral edema. The best cut-off values for ET-1 and c-Fn serum levels for the prediction of severe brain edema were 5.5 fmol/mL (sensitivity 95% and specificity 94%) and 4.5 mg/L (sensitivity 73% and specificity 77%) respectively. ET-1 serum levels >5.5 fmol/mL before t-PA treatment were independently associated with development of severe brain edema (OR, 139.7; CI95%, 19.3 to 1012.2; P<0.0001), after adjustment for baseline stroke severity, early CT signs of infarction, serum levels of cFn >4.5 mg/L, and cardioembolic stroke subtype. CONCLUSIONS: ET-1 serum levels >5.5 fmol/mL are associated with severe brain edema in acute stroke patients treated with t-PA. These results suggest that ET-1 may be a new diagnostic marker for development of severe brain edema in patients with acute ischemic stroke treated with t-PA.

The increase of circulating endothelial progenitor cells after acute ischemic stroke is associated with good outcome.

BACKGROUND AND PURPOSE: Increased circulating endothelial progenitor cells (EPC) have been associated with a low cardiovascular risk and may be involved in endothelial cell regeneration. The present study was designed to evaluate the prognostic value of EPC in acute ischemic stroke. METHODS: Forty-eight patients with a first-ever nonlacunar ischemic stroke were prospectively included in the study within 12 hours of symptoms onset. Stroke severity was evaluated by the National Institutes of Health Stroke Scale, and functional outcome was assessed at 3 months by the modified Rankin Scale (mRS). Infarct volume growth between admission and days 4 to 7 was measured on multiparametric MRI. EPC colonies were defined as early outgrowth colony-forming unit-endothelial cell (CFU-EC). The increment of CFU-EC was quantified during the first week and defined as the absolute difference between the number of CFU-EC at day 7 and admission. The influence of CFU-EC increase on good functional outcome (mRS or=4 during the first week was associated with good functional outcome at 3 months (odds ratio, 30.7; 95% CI, 2.4 to 375.7; P=0.004) after adjustment for baseline stroke severity, ischemic volume and thrombolytic treatment. For each unit increase in the CFU-EC the mean reduction in the growth of infarct volume was 0.39 (0.03 to 0.76) mL (P=0.033). CONCLUSIONS: The increase of circulating EPC after acute ischemic stroke is associated with good functional outcome and reduced infarct growth. These findings suggest that EPC might participate in neurorepair after ischemic stroke.