How Clot Composition Influences Fibrinolysis in the Acute Phase of Stroke: A Proteomic Study of Cerebral Thrombi.

BACKGROUND: The dramatic clinical improvement offered by mechanical thrombectomy raised questions about the relevance of prior intravenous thrombolysis in large-vessel occlusion strokes. Hence, studying intravenous thrombolysis susceptibility and its dependence on thrombus composition is crucial. We used an observational proteomic study of whole thrombi retrieved by mechanical thrombectomy to identify factors associated with fibrin content and fibrinolytic activity (FA). METHODS: In 104 stroke patients, the thrombi proteome was established by mass spectrometry coupled to liquid chromatography. FA was estimated in clots both outside (FAout) by measuring D-dimer levels at the blood-thrombus interface and inside (FAin) by evaluating the ratio of fibrinogen α to its plasmin-cleaved forms using proteomics coupled with protein electrophoresis. The factors associated with fibrin content, FAin, and FAout were determined by intravenous thrombolysis-adjusted linear regression. RESULTS: FAout (P<0.0001) and FAin (P=0.0147) were driven by recombinant tissue-type plasminogen activator (r-tPA) administration (47/104) and thrombus composition. Indeed, FAout was greater with fibrin-rich than erythrocyte-rich thrombi, presumably because of more (r)tPA substrates. Thus, FAout was increased with cardioembolic thrombi (72/104), which are rich in fibrin (P=0.0300). Opposite results were found inside the thrombus, suggesting that (r)tPA penetrability was hampered by the density of the fibrinous cap. Moreover, blood cells had a strong impact on thrombus structure and susceptibility to (r)tPA. Indeed, fibrin content was negatively associated with erythrocyte-specific proteins in the thrombus, admission hematocrit (P=0.0139), and hemoglobin level (P=0.0080), which underlines the key role of erythrocytes in thrombus composition. Also, an increased number of neutrophils impaired FAout (P=0.0225), which suggests that their aggregation around the thrombus prevented the (r)tPA attack. Only FAout was significantly associated with reduced thrombus weight (P=0.0310), increased recanalization rate (P=0.0150), good clinical outcome (P=0.0480), and reduced mortality (P=0.0080). CONCLUSIONS: Proteomics can offer new insights into the close relationship between thrombus composition and susceptibility to fibrinolysis, paving the way for new adjuvant therapies.

SIRT1-Mediated HMGB1 Deacetylation Suppresses Neutrophil Extracellular Traps Related to Blood-Brain Barrier Impairment After Cerebral Venous Thrombosis.

Cerebral venous thrombosis (CVT) is a neurovascular disease with recently increasing incidence. Aseptic inflammatory responses play an important role in the pathology of CVT. Recent studies report that neutrophil extracellular traps (NETs) are major triggers of thrombosis and inflammation in stroke, but their effect on brain injury in CVT requires further validation. In this study, two CVT animal models were used to simulate superior sagittal sinus thrombosis and cortical vein thrombosis. The effects of brain tissue infiltration of NETs and the molecular mechanisms associated with NET formation were deeply explored in combination with proteomics, histology, and serology. The results showed that the cortical vein thrombosis model could be combined with more severe blood-brain barrier (BBB) disruption and showed more severe cerebral hemorrhage. Decreased Sirtuin 1 (SIRT1) expression promotes high mobility group box 1 (HMGB1) acetylation, causing increased cytosolic translocation and extracellular release, and HMGB1 can promote NET formation and recruitment. In addition, corticocerebral accumulation of NETs contributes to BBB damage. This establishes a vicious cycle between BBB damage and NET accumulation. SIRT1 mediated-HMGB1 deacetylation may play a critical role in attenuating BBB damage following CVT. This study employed a combined validation using models of venous sinus thrombosis and cortical vein thrombosis to investigate the deacetylation role of SIRT1, aiming to offer new insights into the pathological mechanisms of brain injury following CVT.

High Mobility Group Box 1 Protein in Cerebral Thromboemboli.

High-mobility group box 1 protein (HMGB1) is a damage-associated molecular pattern (DAMP) involved in neutrophil extracellular trap (NET) formation and thrombosis. NETs are regularly found in cerebral thromboemboli. We here analyzed associated HMGB1 expression in human thromboemboli retrieved via mechanical thrombectomy from 37 stroke patients with large vessel occlusion. HMGB1 was detected in all thromboemboli, accounting for 1.7% (IQR 0.6-6.2%) of the total thromboemboli area and was found to be colocalized with neutrophils and NETs and in spatial proximity to platelets. Correlation analysis revealed that the detection of HMGB1 was strongly related to the number of neutrophils (r = 0.58, p = 0.0002) and platelets (r = 0.51, p = 0.001). Our results demonstrate that HMGB1 is a substantial constituent of thromboemboli causing large vessel occlusion stroke.

Effect of Anti-inflammatory Treatment with AMD3100 and CX3CR1 Deficiency on GABAA Receptor Subunit and Expression of Glutamate Decarboxylase Isoforms After Stroke.

Following stroke, attenuation of detrimental inflammatory pathways might be a promising strategy to improve long-term outcome. In particular, cascades driven by pro-inflammatory chemokines interact with neurotransmitter systems such as the GABAergic system. This crosstalk might be of relevance for mechanisms of neuronal plasticity, however, detailed studies are lacking. The purpose of this study was to determine if treatment with 1,1'-[1,4-phenylenebis(methylene)]bis[1,4,8,11-tetraazacyclotetradecane] (AMD3100), an antagonist to the C-X-C chemokine receptor type 4 (CXCR4) and partial allosteric agonist to CXCR7 (AMD3100) alone or in combination with C-X3-C chemokine receptor type 1 (CX3CR1) deficiency, affect the expression of GABAA subunits and glutamate decarboxylase (GAD) isoforms. Heterozygous, CX3CR1-deficient mice and wild-type littermates were subjected to photothrombosis (PT). Treatment with AMD3100 (0.5 mg/kg twice daily i.p.) was administered starting from day 2 after induction of PT until day 14 after the insult. At this time point, GABAA receptor subunits (α3, ß3, δ), GAD65 and GAD67, and CXCR4 were analyzed from the peri-infarct tissue and homotypic brain regions of the contralateral hemisphere by quantitative real-time PCR and Western Blot. Fourteen days after PT, CX3CR1 deficiency resulted in a significant decrease of the three GABAA receptor subunits in both the lesioned and the contralateral hemisphere compared to sham-operated mice. Treatment with AMD3100 promoted the down-regulation of GABAA subunits and GAD67 in the ipsilateral peri-infarct area, while the ß3 subunit and the GAD isoforms were up-regulated in homotypic regions of the contralateral cortex. Changes in GABAA receptor subunits and GABA synthesis suggest that the CXCR4/7 and CX3CR1 signaling pathways are involved in the regulation of GABAergic neurotransmission in the post-ischemic brain.

Autoantibodies to Annexin A2 and cerebral thrombosis: Insights from a mouse model.

INTRODUCTION: Antiphospholipid syndrome (APS) is an autoimmune disorder manifested by thromboembolic events, recurrent spontaneous abortions and elevated titers of circulating antiphospholipid antibodies. In addition, the presence of antiphospholipid antibodies seems to confer a fivefold higher risk for stroke or transient ischemic attack. Although the major antigen of APS is ß2 glycoprotein I, it is now well established that antiphospholipid antibodies are heterogeneous and bind to various targets. Recently, antibodies to Annexin A2 (ANXA2) have been reported in APS. This is of special interest since data indicated ANXA2 as a key player in fibrinolysis. Therefore, in the present study we assessed whether anti-ANXA2 antibodies play a pathological role in thrombosis associated disease. MATERIALS AND METHODS: Mice were induced to produce anti-ANXA2 antibodies by immunization with ANXA2 (iANXA2) and control mice were immunized with adjuvant only. A middle cerebral artery occlusion stroke model was applied to the mice. The outcome of stroke severity was assessed and compared between the two groups. RESULTS: Our results indicate that antibodies to ANXA2 lead to a more severe stroke as demonstrated by a significant larger stroke infarct volume (iANXA2 133.9 ± 3.3 mm3 and control 113.7 ± 7.4 mm3; p = 0.017) and a more severe neurological outcome (iANXA2 2.2 ± 0.2, and control 1.5 ± 0.18; p = 0.03). CONCLUSIONS: This study supports the hypothesis that auto-antibodies to ANXA2 are an independent risk factor for cerebral thrombosis. Consequently, we propose screening for anti-ANXA2 antibodies should be more widely used and patients that exhibit the manifestations of APS should be closely monitored by physicians.

4-Hydroxyl-2-Nonenal Localized Expression Pattern in Retrieved Clots is Associated with Large Artery Atherosclerosis in Stroke Patients.

OBJECTIVES: The relationship between stroke etiology and clot pathology remains controversial. MATERIALS AND METHODS: We performed histological analysis of clots retrieved from 52 acute ischemic stroke patients using hematoxylin and eosin staining and immunohistochemistry (CD42b and oxidative/hypoxic stress markers). The correlations between clot composition and the stroke etiological group (i.e., cardioembolic, cryptogenic, or large artery atherosclerosis) were assessed. RESULTS: Of the 52 clots analyzed, there were no significant differences in histopathologic composition (e.g., white blood cells, red blood cells, fibrin, and platelets) between the 3 etiological groups (P = .92). By contrast, all large artery atherosclerosis clots showed a localized pattern with the oxidative stress marker 4-hydroxyl-2-nonenal (P < .01). From all 52 clots, 4-hydroxyl-2-nonenal expression patterns were localized in 28.8% of clots, diffuse in 57.7% of clots, and no signal in 13.5% of clots. CONCLUSIONS: A localized pattern of 4-hydroxyl-2-nonenal staining may be a novel and effective marker for large artery atherosclerosis (sensitivity 100%, specificity 82%).

Prediction of cerebral venous thrombosis with a new clinical score and D-dimer levels.

OBJECTIVE: To investigate prediction of cerebral venous thrombosis (CVT) by clinical variables and D-dimer levels. METHODS: This prospective multicenter study included consecutive patients with clinically possible CVT. On admission, patients underwent clinical examination, blood sampling for D-dimers measuring (ELISA test), and magnetic resonance/CT venography. Predictive value of clinical variables and D-dimers for CVT was calculated. A clinical score to stratify patients into groups with low, moderate, or high CVT risk was established with multivariate logistic regression. RESULTS: CVT was confirmed in 26.2% (94 of 359) of patients by neuroimaging. The optimal estimate of clinical probability was based on 6 variables: seizure(s) at presentation (4 points), known thrombophilia (4 points), oral contraception (2 points), duration of symptoms >6 days (2 points), worst headache ever (1 point), and focal neurologic deficit at presentation (1 point) (area under the curve [AUC] 0.889). We defined 0 to 2 points as low CVT probability (negative predictive value [NPV] 94.1%). Of the 186 (51.8%) patients who had a low probability score, 11 (5.9%) had CVT. The frequency of CVT was 28.3% (34 of 120) in patients with a moderate (3-5 points) and 92.5% (49 of 53) in patients with a high (6-12 points) probability score. All low CVT probability patients with CVT had D-dimers >500 µg/L. Predictive value of D-dimers for CVT for >675 µg/L (best cutoff) vs >500 µg/L was as follows: sensitivity 77.7%, specificity, 77%, NPV 90.7%, and accuracy 77.2% vs sensitivity 89.4%, specificity 66.4%, NPV 94.6%, and accuracy 72.4%, respectively. Adding the clinical score to D-dimers >500 µg/L resulted in the best CVT prediction score explored (at the cutoff ≥6 points: sensitivity 83%/specificity 86.8%/NPV 93.5%/accuracy 84.4%/AUC 0.937). CONCLUSION: The proposed new clinical score in combination with D-dimers may be helpful for predicting CVT as a pretest score; none of the patients with CVT showed low clinical probability for CVT and D-dimers <500 µg/L. CLINICALTRIALSGOV IDENTIFIER: NCT00924859.

Acute ischemic stroke thrombi have an outer shell that impairs fibrinolysis.

OBJECTIVES: Thrombi responsible for large vessel occlusion (LVO) in the setting of acute ischemic stroke (AIS) are characterized by a low recanalization rate after IV thrombolysis. To test whether AIS thrombi have inherent common features that limit their susceptibility to thrombolysis, we analyzed the composition and ultrastructural organization of AIS thrombi causing LVO. METHODS: A total of 199 endovascular thrombectomy-retrieved thrombi were analyzed by immunohistology and scanning electron microscopy (SEM) and subjected to ex vivo thrombolysis assay. The relationship between thrombus organization and thrombolysis resistance was further investigated in vitro using thrombus produced by recalcification of citrated whole blood. RESULTS: SEM and immunohistology analyses revealed that, although AIS thrombus composition and organization was highly heterogeneous, AIS thrombi shared a common remarkable structural feature in the form of an outer shell made of densely compacted thrombus components including fibrin, von Willebrand factor, and aggregated platelets. In vitro thrombosis experiments using human blood indicated that platelets were essential to the formation of the thrombus outer shell. Finally, in both AIS and in vitro thrombi, the thrombus outer shell showed a decreased susceptibility to tissue plasminogen activator-mediated thrombolysis as compared to the thrombus inner core. INTERPRETATION: Irrespective of their etiology and despite their heterogeneity, intracranial thrombi causing LVO have a core shell structure that influences their susceptibility to thrombolysis.

Epigenetic Alterations Induced by Photothrombotic Stroke in the Rat Cerebral Cortex: Deacetylation of Histone h3, Upregulation of Histone Deacetylases and Histone Acetyltransferases.

Ischemic penumbra that surrounds a stroke-induced infarction core is potentially salvageable; however, mechanisms of its formation are not well known. Covalent modifications of histones control chromatin conformation, gene expression and protein synthesis. To study epigenetic processes in ischemic penumbra, we used photothrombotic stroke (PTS), a stroke model in which laser irradiation of the rat brain cortex photosensitized by Rose Bengal induces local vessel occlusion. Immunoblotting and immunofluorescence microscopy showed decrease in acetylation of lysine 9 in histone H3 in penumbra at 1, 4 or 24 h after PTS. This was associated with upregulation of histone deacetylases HDAC1 and HDAC2, but not HDAC4, which did not localize in the nuclei. HDAC2 was found in cell nuclei, HDAC4 in the cytoplasm and HDAC1 both in nuclei and cytoplasm. Histone acetyltransferases HAT1 and PCAF (p300/CBP associated factor) that acetylated histone H3 synthesis were also upregulated, but lesser and later. PTS increased localization of HDAC2 and HAT1 in astroglia. Thus, the cell fate in PTS-induced penumbra is determined by the balance between opposite tendencies leading either to histone acetylation and stimulation of gene expression, or to deacetylation and suppression of transcriptional processes and protein biosynthesis. These epigenetic proteins may be the potential targets for anti-stroke therapy.

Extent of Ischemic Brain Injury After Thrombotic Stroke Is Independent of the NLRP3 (NACHT, LRR and PYD Domains-Containing Protein 3) Inflammasome.

Background and Purpose- A major process contributing to cell death in the ischemic brain is inflammation. Inflammasomes are multimolecular protein complexes that drive inflammation through activation of proinflammatory cytokines, such as IL (interleukin)-1ß. Preclinical evidence suggests that IL-1ß contributes to a worsening of ischemic brain injury. Methods- Using a mouse middle cerebral artery thrombosis model, we examined the inflammatory response after stroke and the contribution of the NLRP3 (NACHT, LRR and PYD domains-containing protein 3) inflammasome to ischemic injury. Results- There was a marked inflammatory response after stroke characterized by increased expression of proinflammatory cytokines and NLRP3 and by recruitment of leukocytes to the injured tissue. Targeting NLRP3 with the inhibitor MCC950, or using mice in which NLRP3 was knocked out, had no effect on the extent of injury caused by stroke. Conclusions- These data suggest that the NLRP3 pathway does not contribute to the inflammation exacerbating ischemic brain damage, contradicting several recent reports to the contrary.

Histological dating of subdural hematoma in infants.

BACKGROUND: After infant deaths due to non-accidental head injury (NAHI) with subdural hematoma (SDH), the magistrates ask experts to date the traumatic event. To do so, the expert only has tools based on adult series of NAHI. We aimed to develop an SDH dating system applicable to infants aged under 3 years. METHODS AND RESULTS: We studied a retrospective multicenter collection of 235 infants who died between the ages of 0 and 36 months, diagnosed with SDH by forensic pathological examination and with known posttraumatic interval (PTI). Two pathologists assessed blindly and independently 12 histomorphological criteria relating to the clot and 14 relating to the dura mater in 73 victims (31 girls, 42 boys) whose median age was 3.8 months. Histopathological changes were significantly correlated with PTI for the appearance of red blood cells (RBCs) and the presence or absence of siderophages, and regarding the dura mater, the quantity of lymphocytes, macrophages, and siderophages; presence or absence of hematoidin deposits; collagen and fibroblast formation; neomembrane thickness; and presence or absence of neovascularization. Dating systems for SDH in adults are not applicable to infants. Notably, neomembrane of organized connective tissue is formed earlier in infants than in adults. CONCLUSION: Our dating system improves the precision and reliability of forensic pathological expert examination of NAHI, particularly for age estimation of SDH in infants. However, the expert can only define a time interval. Histopathology is indispensable to detect repetitive trauma.

Gender-Specific Relationship Between Uric Acid Levels and Prognosis After Cerebral Venous Thrombosis.

BACKGROUND: Uric Acid (UA) has been known to play a neuroprotective role in ischemic stroke patients. However, the relationship between UA levels and prognosis in patients with Cerebral Venous Thrombosis (CVT) has not been investigated. METHOD: A total of 228 CVT patients were retrospectively identified and were divided into three groups according to UA levels. Functional outcome was evaluated by the modified Rankin Scale (mRS). Multivariate logistic regression analysis was conducted to evaluate the relation between UA levels and functional outcome after CVT. RESULTS: UA levels were significantly higher in male than female patients (274.5±125.9 vs. 197.4±81.6, P < 0.001). The association between UA levels and mortality was modified by sex (Pinteraction = 0.010). Multivariate logistic regression analysis indicated that a higher UA level was associated with a decreased risk of mRS of 3 to 6 in female patients (Odds Ratio [OR] = 0.204; 95% Confidence Interval [CI], 0.044-0.938), but not in male patients (OR= 0.441; 95% CI, 0.033- 5.339). Similarly, a high UA level was associated with a decreased risk of mortality in female patients (OR= 0.058; 95% CI, 0.008-0.437), but not in male patients (OR= 2.309; 95% CI, 0.057- 93.308). In addition, each 1 µmol/L increase in UA levels was also associated with a lower risk of poor clinical outcome and mortality for female patients, but not in male patients. CONCLUSION: Our study demonstrated that there might be a gender-specific relationship between UA levels and clinical outcome in patients with CVT. Higher UA levels were associated with better prognosis in female patients, but not in male patients.

Endothelial progenitor cell miR-126 promotes homing of endothelial progenitor cells within arterial thrombus in patients with cerebral infarction and its molecular mechanism.

OBJECTIVE: The present study was designed to investigate the effect of microRNA-126 (miR-126) on the migration and homing of endothelial progenitor cells (EPCs) within arterial thrombus of cerebral infarction patients. MATERIALS AND METHODS: EPCs from rat bone marrow were isolated, and miR-126 overexpressed EPCs were constructed by lentiviral transfection. Then, the middle cerebral artery occlusion (MCAO) model was established by the method of thread ligation. Successfully established model rats were randomly divided into miR-126 overexpression EPC group, miR-126 wild type EPC group, and normal saline group. One day after the infarction, the miR-126 overexpression EPCs, miR-126 wild type EPCs, and normal saline, were injected into the lateral ventricle of the corresponding groups. Also, the transplanted cells were tracked by cell dye SPDiIC18. The expression of tight junction proteins ZO-1 and Claudin-5 in brain tissue was detected by Western blotting. RESULTS: Transplanted cells were detected in the cerebral infarction area 3 days after transplantation by cell dye SP-DiIC18. The number of homing EPCs in miR-126 overexpression group was significantly higher than that of miR-126 wild type EPC group (p < 0.05). Also, the protein expression of ZO-1 and Claudin-5 in the miR- 126 overexpression EPC group was significantly higher compared with that of the miR-126 wild type EPC group and the normal saline group. CONCLUSIONS: miR-126 overexpression EPCs, which were transplanted in the lateral ventricle, can home to the cerebral infarction areas via increasing increase.

Ischemic Stroke: Histological Thrombus Composition and Pre-Interventional CT Attenuation Are Associated with Intervention Time and Rate of Secondary Embolism.

BACKGROUND AND PURPOSE: The introduction of stent retrievers has made the complete extraction and histological analysis of human thrombi possible. A number of large randomized trials have proven the efficacy of thrombectomy for ischemic stroke; however, thrombus composition could have an impact on the efficacy and risk of the intervention. We therefore investigated the impact of histologic thrombus features on interventional outcome and procedure-related embolisms. For a pre-interventional estimation of histologic features and outcome parameters, we assessed the pre-interventional CT attenuation of the thrombi. METHODS: We prospectively included all consecutive patients with occlusion of the middle cerebral artery who underwent thrombectomy between December 2013 and February 2016 at our university medical center. Samples were histologically analyzed (H&E, Elastica van Gieson, Prussian blue); additionally, immunohistochemistry for CD3, CD20, and CD68/KiM1P was performed. Main thrombus components (fibrin, erythrocytes, and white blood cells) were determined and compared to intervention time, frequency of secondary embolisms, as well as additional clinical and interventional parameters. Additionally, we assessed the pre-interventional CT attenuation of the thrombi in relation to the unaffected side (rHU) and their association with histologic features. RESULTS: One hundred eighty patients were included; of these, in 168 patients (93.4%), complete recanalization was achieved and 27 patients (15%) showed secondary embolism in the control angiogram. We observed a significant association of high amounts of fibrin (p < 0.001), low percentage of red blood cells (p < 0.001), and lower rHU (p < 0.001) with secondary embolism. Higher rHU values were significantly associated with higher amounts of fibrin (p ≤ 0.001) and low percentage of red blood cells (p ≤ 0.001). Additionally, high amounts of fibrin were associated with longer intervention times (p ≤ 0.001), whereas thrombi with high amounts of erythrocytes correlated with shorter intervention times (p ≤ 0.001). ROC analysis revealed reliable prediction of secondary embolisms for low rHU (AUC = 0.746; p ≤ 0.0001), low amounts of RBC (AUC = 0.764; p ≤ 0.0001), and high amounts of fibrin (AUC = 0.773; p ≤ 0.0001). CONCLUSIONS: Fibrin-rich thrombi with low erythrocyte percentage are significantly associated with longer intervention times. Embolisms in the thrombectomy process occur more often in thrombi with a small fraction of red blood cells and a low CT-density, suggesting a higher fragility of these thrombi.

Mutation of the Kunitz-type proteinase inhibitor domain in the amyloid ß-protein precursor abolishes its anti-thrombotic properties in vivo.

INTRODUCTION: Kunitz proteinase inhibitor (KPI) domain-containing forms of the amyloid ß-protein precursor (AßPP) inhibit cerebral thrombosis. KPI domain-lacking forms of AßPP are abundant in brain. Regions of AßPP other than the KPI domain may also be involved with regulating cerebral thrombosis. To determine the contribution of the KPI domain to the overall function of AßPP in regulating cerebral thrombosis we generated a reactive center mutant that was devoid of anti-thrombotic activity and studied its anti-thrombotic function in vitro and in vivo. METHODS: To determine the extent of KPI function of AßPP in regulating cerebral thrombosis we generated a recombinant reactive center KPIR13I mutant devoid of anti-thrombotic activity. The anti-proteolytic and anti-coagulant properties of wild-type and R13I mutant KPI were investigated in vitro. Cerebral thrombosis of wild-type, AßPP knock out and AßPP/KPIR13I mutant mice was evaluated in experimental models of carotid artery thrombosis and intracerebral hemorrhage. RESULTS: Recombinant mutant KPIR13I domain was ineffective in the inhibition of pro-thrombotic proteinases and did not inhibit the clotting of plasma in vitro. AßPP/KPIR13I mutant mice were similarly deficient as AßPP knock out mice in regulating cerebral thrombosis in experimental models of carotid artery thrombosis and intracerebral hemorrhage. CONCLUSIONS: We demonstrate that the anti-thrombotic function of AßPP primarily resides in the KPI activity of the protein.

Plasminogen activator inhibitor links obesity and thrombotic cerebrovascular diseases: The roles of PAI-1 and obesity on stroke.

One of the global socioeconomic phenomena occurred during the last decades is the increased prevalence of obesity, with direct consequence on the risk of developing thrombotic disorders. As the physiological inhibitor of tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA), plasminogen activator inhibitor-1 (PAI-1) is well known for its role in fibrinolysis. More and more evidences have shown that PAI-1 involves in physiopathologic mechanisms of many diseases and metabolic disorder. Increased serum level of PAI-1 has been observed in obesity and it also contributes to the development of adipose tissue and then has effects on obesity. Meantime, obesity affects also the PAI-1 levels. These evidences indicate the complicated interaction between PAI-1 and obesity. Many clinic studies have confirmed that obesity relates to the stroke outcome although there are many contradictory results. Simultaneously, correlation is found between plasma PAI-1 and thrombotic cerebrovascular diseases. This article reviews contemporary knowledge regarding the complex interplay of obesity, PAI-1 and stroke.

Effect of Melilotus officinalis extract on the apoptosis of brain tissues by altering cerebral thrombosis and inflammatory mediators in acute cerebral ischemia.

Present investigation evaluates the protective effect of Melilotus officinalis (MO) extract on the brain tissues in acute cerebral ischemia. Acute cerebral ischemia was induced by occlusion of carotid artery and rats with cerebral ischemia were treated with MO (100, 250 & 500mg/kg) for the duration of three days. Cerebral ischemia was confirmed by estimating infract volume and neurological deficit score. Moreover biochemical parameters in plasma such as 6-keto-PGF1α and TXB2 and concentration of cytokine, oxidative stress, apoptosis ratio and protein expressions of Bcl2 & Bax were estimated in the brain tissues. It was observed that treatment with MO significantly (p<0.01) decreases the infract volume and neurological deficit score than negative control group. There was significant decrease (p<0.01) in the oxidative stress and cytokine in the brain tissues and increase in the plasma concentration of 6-keto-PGF1α in MO treated group of rats compared to negative control group. Plasma concentration of TXB 2 was significantly enhanced in MO treated group compared to negative control group of rats. It was also found that treatment with MO ameliorates the apoptosis induced by cerebral ischemia. Present study concludes that MO ameliorates apoptosis of brain tissues in cerebral ischemic rats by decreasing cerebral thrombosis, oxidative stress and inflammatory mediators.

Chronic stress exposure following photothrombotic stroke is associated with increased levels of Amyloid beta accumulation and altered oligomerisation at sites of thalamic secondary neurodegeneration in mice.

Exposure to severe stress following stroke is recognised to complicate the recovery process. We have identified that stress can exacerbate the severity of post-stroke secondary neurodegeneration in the thalamus. In this study, we investigated whether exposure to stress could influence the accumulation of the neurotoxic protein Amyloid-ß. Using an experimental model of focal cortical ischemia in adult mice combined with exposure to chronic restraint stress, we examined changes within the contra- and ipsilateral thalamus at six weeks post-stroke using Western blotting and immunohistochemical approaches. Western blotting analysis indicated that stroke was associated with a significant enhancement of the 25 and 50 kDa oligomers within the ipsilateral hemisphere and the 20 kDa oligomer within the contralateral hemisphere. Stroked animals exposed to stress exhibited an additional increase in multiple forms of Amyloid-beta oligomers. Immunohistochemistry analysis confirmed that stroke was associated with a significant accumulation of Amyloid-beta within the thalami of both hemispheres, an effect that was exacerbated in stroke animals exposed to stress. Given that Amyloid-beta oligomers, most notably the 30-40 and 50 kDa oligomers, are recognised to correlate with accelerated cognitive decline, our results suggest that monitoring stress levels in patients recovering from stroke may merit consideration in the future.