Current Neurovascular Research - Volume 13, Issue 3, 2016

The prognostic role of increased mean platelet volume (MPV), as an indicator of platelet activation and large, more reactive platelets, in clinical and functional outcome of ischemic stroke is still conflicting. Studies are not currently available on the association between MPV and stroke recovery after neurorehabilitation. The relationship between MPV and clinical and functional outcome measures was assessed in twenty-four patients in the acute phase of first-ever ischemic stroke, and before and after 8-week intensive multifunctional neurorehabilitation. Neurorehabilitation was associated with improved scores of the National Institutes of Health Stroke Scale (NIHSS), the modified Rankin Scale (mRS), and the modified PULSES profile (mPULSES). When compared with apparently healthy subjects, higher MPV values were observed in stroke patients 24 hours after stroke and before neurorehabilitative treatment started not later than 14 days after stroke. Decreased MPV values were found after neurorehabilitation, even if the absolute values were still higher than those detected in control subjects. No correlation was observed between MPV values and scores of the NIHSS and mRS scales evaluated in stroke acute phase. No correlation was also observed before and after neurorehabilitative treatment between MPV and NIHSS, mRS and mPULSES scores. Our data provide evidence of the effectiveness of neurorehabilitation on modulating MPV values and support the hypothesis that high MPV could represent an expression of proinflammatory condition of the stroke patients, realistically pre-existent to acute ischemic event, than a marker of neurologic deficit and disability or of stroke recovery including motor performance and functional independence.

While the clinical efficacy of aspirin in cerebral thrombosis prevention has been well established, its mechanism of action is still controversial. In an effort to better understand these mechanisms and to identify potential biomarkers, comparative proteomic analysis between 18 patients both pre-aspirin treatment at the time of cerebral thrombotic onset (control group) and post-aspirin treatment (experiment group) was carried out using two-dimensional gel electrophoresis (2-DE) in combination with matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDITOF/ MS). Of the 228 2-DE identified differentially expressed protein spots, 11 proteins showed more than a 1.5-fold difference. Of these, vitamin D-binding protein (DBP) and actin were further examined via Western blot and showed consistent results, with DBP levels significantly increased post-aspirin treatment (114.04 ± 16.69) relative to pre-treatment (66.33 ± 5.61) while actin showed the opposite trend (p < 0.01 for both comparisons). Next, co-immunoprecipitation analysis of DBP and actin showed direct binding. Furthermore, a protein–protein interaction network of DBP and the other differentially expressed proteins was constructed using Ingenuity Pathway Analysis software. These results suggest that DBP acts in the actin scavenge system and consequently the increase in DBP levels correlated with aspirin therapy in cerebral thrombotic patients. These findings also suggest that aspirin may prevent platelet aggregation and thrombosis through the actions of DBP and other DBP related proteins.

Previous clinical studies suggest that intravenous (IV) recombinant tissue plasminogen activator (rt-PA) benefits stroke patients regardless of the underlying etiology. In this study, we assessed the possible differences in response to IV rt-PA between cardioembolic stroke and other stroke subtypes. A total of 303 consecutive stroke ischemic patients (from January 2005 to April 2014) admitted to our Stroke Unit and treated with IV rt-PA were retrospectively reviewed. All patients were classified in two groups: Cardioembolic (CE) and Non-Cardioembolic (NCE). We analyzed a total of 303 patients. Thirty patients died in the first hours after fibrinolysis and no statistically significant differences were found in two groups (14 CE vs 18 N-CE). We observed a significant differences in clinical outcome in terms of symptoms ”improvement” (p<0.01 x2) and symptoms” regression” (p<0.057 x2) even if this last result did not reach statistical significance in CE patients respect to N-CE patients. In conclusion, the intravenous fibrinolysis is more effective in CE group than in N-CE regarding symptoms ”improvement” and the PFO-Stroke patients treated with fibrinolysis have better outcome than other patients and they have high rate of symptoms” regression”. Moreover the main predictor of good outcomes were younger age and milder stroke severity on hospital admission.

Dabigatran etexilate (DE), a direct-acting, oral inhibitor of thrombin, significantly reduces the risk of stroke compared with traditional anticoagulants, without increasing the risk of major bleeding. However, studies on the fate of cerebral tissue after ischemic stroke in patients receiving DE are sparse and the role of dabigatran-mediated reduction of thrombin in this context has not yet been investigated. Here, we investigated whether pretreatment with DE reduces thrombin-mediated pro-inflammatory mechanisms and leakage of the blood–brain barrier (BBB) following ischemic stroke in rats. Male Wistar rats received DE (15 mg/kg) or a vehicle solution 1 hour before transient middle cerebral artery occlusion (tMCAO) for 90 minutes. Infarct volume, neurologic outcome and intracranial hemorrhage (ICH) were determined after tMCAO. Thrombin generation was indirectly assessed by measuring thrombin/antithrombin III complex. Microvascular patency was evaluated histologically. Cytokine expression and immunoreactivity of cluster of differentiation (CD) 68 were examined to characterize inflammatory processes after pretreatment with DE. BBB integrity was examined by quantifying brain edema. Rats given DE revealed a significant reduction in infarct size without an increase in ICH and significant recovery of neurologic deficits compared to controls. Administration of DE decreased thrombin generation and thrombus formation, dampened the CD68-immunoreactivity and attenuated pro-inflammatory cytokine expression in the cerebral parenchyma ipsilateral to the ischemic lesion. BBB permeability was unaltered following treatment with DE. In summary, prophylactic anticoagulation with DE improves stroke outcome by reducing thrombin-induced inflammation and thrombus formation without increasing the rate of ICH.

The expression levels of different vascular endothelial growth factor A (VEGF) isoforms are associated with the angiogenesis and the patient’s prognoses in human cancers. Ribosomes specifically scan from 5’ to 3’ CUG initiation codon in the long 5’-untranslated region (5’-UTR) of the VEGF mRNA, resulting in the generation of high mol wt VEGF isoform [call large VEGF (L-VEGF)]. Alternative splicing of VEGF mRNA transcripts results in several isoforms with distinct properties that are dependent up their exon compositions. In this study, we observed two novel kinds of splicing VEGF isoforms that transcripted at the first upstream CUG codon, and which we have named large-VEGF144 (LVEGF144), and large-VEGF138 (L-VEGF138). The expression levels of messenger RNA for the different VEGF splice forms were analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR). After DNA sequencing, the genetic structure of L-VEGF144 involved not only a partial exon 1, exon 6a, and exons 7-8, but also an unique 108- nucleotides insertion of VEGF intron 5 interposed between exon 1 and exon 6. At the same time, L-VEGF144 lacked most of the Nterminal fragments (exons 1-5). We further found that a specific detection model could easily and rapidly confirm the presence of L-VEGF144 mRNA fragments in the biopsies or cell lines via RT-PCR assay. In addition, we used visible fluorescent fusion proteins to prove that both L-VEGF144 and L-VEGF138 have nuclear localization ability. Taken together, the findings of this study indicate that, unlike previously identified isoforms, these novel VEGF isoforms are likely to suggest a further level of complexity in the angiogenic process.