Protective effect of grape seed extract and orlistat co-treatment against stroke: Effect on oxidative stress and energy failure

Ischemic stroke is a major health concern and a leading cause of mortality worldwide. Oxidative stress is an early event in the course of stroke inducing neuro-inflammation and cell death. Grape seed extract (GSE) is a natural phytochemical mixture exhibiting antioxidant, anti-inflammatory and neuroprotective properties. Orlistat (ORL) is an anti-obesity agent and a gastro-intestinal lipase inhibitor which showed recently beneficial effects on brain lipotoxicity. Recent studies reported the increase of lipase activity upon stroke which led us to investigate the neuroprotective effect of ORL on rat brain I/R injury as well as the putative synergism with GSE. I/R insult infarcted the brain parenchyma as assessed by TTC staining, induced an oxidative stress as revealed by increased lipoperoxidation along with alteration of antioxidant enzymes activities which was corrected using the cotreatment of ORL + GSE. I/R also disturbed the main metabolic pathways involved in brain fueling as glycolysis, neoglucogenesis, glycogenolysis, TCA cycle and electron transfer chain (ETC) complexes. These disturbances were also corrected with the cotreatment ORL + GSE which maintained energetic activities near to the control level. I/R also disrupted transition metals distribution, along with associated enzymes as tyrosinase, LDH or glutamine synthetase activities and induced hippocampal inflammation as revealed by glycogen depletion from dentate gyrus area along with depressed anti-inflammatory IL1β cytokine and increased pro-inflammatory CD68 antigen. Interestingly almost all I/R-induced disturbances were corrected either partially upon ORL and GSE on their own and the best neuroprotection was obtained in the presence of both drugs (ORL + GSE) enabling robust neuroprotection of the sub granular zone within hippocampal dentate gyrus area.

Genistein-3'-sodium sulfonate Attenuates Neuroinflammation in Stroke Rats by Down-Regulating Microglial M1 Polarization through α7nAChR-NF-κB Signaling Pathway

Microglial M1 depolarization mediated prolonged inflammation contributing to brain injury in ischemic stroke. Our previous study revealed that Genistein-3'-sodium sulfonate (GSS) exerted neuroprotective effects in ischemic stroke. This study aimed to explore whether GSS protected against brain injury in ischemic stroke by regulating microglial M1 depolarization and its underlying mechanisms. We established transient middle cerebral artery occlusion and reperfusion (tMCAO) model in rats and used lipopolysaccharide (LPS)-stimulated BV2 microglial cells as in vitro model. Our results showed that GSS treatment significantly reduced the brain infarcted volume and improved the neurological function in tMCAO rats. Meanwhile, GSS treatment also dramatically reduced microglia M1 depolarization and IL-1β level, reversed α7nAChR expression, and inhibited the activation of NF-κB signaling in the ischemic penumbra brain regions. These effects of GSS were further verified in LPS-induced M1 depolarization of BV2 cells. Furthermore, pretreatment of α7nAChR inhibitor (α-BTX) significantly restrained the neuroprotective effect of GSS treatment in tMCAO rats. α-BTX also blunted the regulating effects of GSS on neuroinflammation, M1 depolarization and NF-κB signaling activation. This study demonstrates that GSS protects against brain injury in ischemic stroke by reducing microglia M1 depolarization to suppress neuroinflammation in peri-infarcted brain regions through upregulating α7nAChR and thereby inhibition of NF-κB signaling. Our findings uncover a potential molecular mechanism for GSS treatment in ischemic stroke.

H2S prevents peripheral immune cell invasion, increasing [Ca2+]i and excessive phagocytosis following hypoxia-ischemia injury in neonatal mice

We previously reported that L-Cysteine, H2S donor, remarkably attenuated neuroinflammation following hypoxia-ischemia (HI) brain injury in neonatal mice. However, its anti-inflammatory mechanism for HI insult is still unknown. The study focus on the effects of L-Cysteine on immune cell populations, Ca2+ mobilization and phagocytosis after neonatal HI. We found that L-Cysteine treatment skewed CD11b+/CD45low microglia and CD11b+/CD45high brain monocytes/macrophages towards a more anti-inflammatory property 72 h after HI-injured brain. Moreover, L-Cysteine treatment reduced cerebral infiltration of CD4 T cells 7 days following HI insult. Furthermore, CD4 T cell subset analysis revealed that L-Cysteine treatment decreased Th1 and Th2 counts, while increased Th17/Th2 ratio. Moreover, L-Cysteine treatment suppressed LPS-induced cytosolic Ca2+ and LPS-stimulated phagocytosis in primary microglia. The anti-inflammatory effect of L-Cysteine was associated with improving neurobehavioral impairment following HI insult. Our results demonstrate L-Cysteine treatment suppressed the invasion of peripheral immune cells, increasing [Ca2+]i and excessive phagocytosis to improve neurobehavioral deficits following hypoxia-ischemia injury in neonatal mice by H2S release.

Protective Effect of Eichhornia Crassipes Against Cerebral Ischemia Reperfusion Injury in Normal and Diabetic rats

Eichhornia crassipes (EC) is well reported to modify inflammatory response, oxidative stress which are key pathophysiological finding of cerebral reperfusion injury, alongside it is reported to reduce cholesterol and blood glucose levels, and therefore present work was designed to investigate the effect of EC on cerebral reperfusion injury in normal and diabetic rats. Each protocol comprised cerebral ischemia (CI) for 30 min followed by reperfusion(R) for 1 h. Animals were treated with EC (100 mg/kg p.o) for seven days. At the end of the experiment, brain tissue was utilized for the measurement of oxidative stress markers, inflammatory response, infarct size and histopathological findings. EC treated rats demonstrated a significant reduction in infarct sizes when compared with CI/R and Diabetic CI/R (DCI/R) group of rats. EC treatment demonstrated a significant decreased in malondialdehyde, nitric oxide and blood glucose levels and a significant increase in the level of reduced glutathione, superoxide dismutase catalase and insulin levels, showed modification in oxidative stress. EC treatment confirmed a significant decrease in myeloperoxidase, C - reactive protein and TNF-α levels indicated a change in the inflammatory response. Histopathological findings revealed a reversal of damage in EC treated rats. EC treatmen reduced DNA fragmentation of brain tissue in treated animals. EC was found to be cerebroprotective against CI/R along with DCI/R group of rats by anti-inflammatory and antioxidant activities.

Development of a Neuroprotective Erythropoietin Modified with a Novel Carrier for the Blood-Brain Barrier

Extremely high doses of erythropoietin (EPO) has been used for neuroprotection in ischemia-reperfusion brain injury to deliver sufficient amounts of EPO across the blood-brain barrier (BBB); however, harmful outcomes were observed afterward. We aimed to test the ability of HBHAc (heparin-binding haemagglutinin adhesion c), an intracellular delivery peptide for macromolecules, as an EPO carrier across the BBB. The cellular internalization and transcytosis ability of HBHAc-modified EPO (EPO-HBHAc) were evaluated in bEnd.3 cells and in the bEnd.3/CTX TNA2 co-culture BBB model, respectively. Subsequently, the NMDA-induced-toxicity model and ischemia-reperfusion rat model were used to understand the neuronal protective activity of EPO-HBHAc. The biodistribution of EPO-HBHAc was demonstrated in rats by the quantification of EPO-HBHAc in the brain, plasma, and organs by ELISA. Our results demonstrate that EPO-HBHAc exhibited significantly higher cellular internalization in dose- and time-dependent manners and better transcytosis ability than EPO. In addition, the transported EPO-HBHAc in the co-culture transwell system maintained the neuronal protective activity when primary rat cortical neurons underwent NMDA-induced toxicity. The calculated cerebral infarction area of rats treated with EPO-HBHAc was significantly reduced compared to that of rats treated with EPO (29.9 ± 7.0% vs 48.9 ± 7.9%) 24 h after occlusion in 3VO rat experiments. Moreover, the EPO amount in both CSF and damaged cortex from the EPO-HBHAc group was 4.0-fold and 3.0-fold higher than the EPO group, respectively. These results suggest that HBHAc would be a favorable tool for EPO brain delivery and would further extend the clinical applications of EPO in neuroprotection.

Interventions for preventing silent cerebral infarcts in people with sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta globin) genes. SCD can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Silent cerebral infarcts are the commonest neurological complication in children and probably adults with SCD. Silent cerebral infarcts also affect academic performance, increase cognitive deficits and may lower intelligence quotient.

OBJECTIVES

To assess the effectiveness of interventions to reduce or prevent silent cerebral infarcts in people with SCD.

SEARCH METHODS

We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 14 November 2019. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register: 07 October 2019.

SELECTION CRITERIA

Randomised controlled trials comparing interventions to prevent silent cerebral infarcts in people with SCD. There were no restrictions by outcomes examined, language or publication status.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

We included five trials (660 children or adolescents) published between 1998 and 2016. Four of the five trials were terminated early. The vast majority of participants had the haemoglobin (Hb)SS form of SCD. One trial focused on preventing silent cerebral infarcts or stroke; three trials were for primary stroke prevention and one trial dealt with secondary stroke prevention. Three trials compared the use of regular long-term red blood cell transfusions to standard care. Two of these trials included children with no previous long-term transfusions: one in children with normal transcranial doppler (TCD) velocities; and one in children with abnormal TCD velocities. The third trial included children and adolescents on long-term transfusion. Two trials compared the drug hydroxyurea and phlebotomy to long-term transfusions and iron chelation therapy: one in primary prevention (children), and one in secondary prevention (children and adolescents). The quality of the evidence was moderate to very low across different outcomes according to GRADE methodology. This was due to trials being at high risk of bias because they were unblinded; indirectness (available evidence was only for children with HbSS); and imprecise outcome estimates. Long-term red blood cell transfusions versus standard care Children with no previous long-term transfusions and higher risk of stroke (abnormal TCD velocities or previous history of silent cerebral infarcts) Long-term red blood cell transfusions may reduce the incidence of silent cerebral infarcts in children with abnormal TCD velocities, risk ratio (RR) 0.11 (95% confidence interval (CI) 0.02 to 0.86) (one trial, 124 participants, low-quality evidence); but make little or no difference to the incidence of silent cerebral infarcts in children with previous silent cerebral infarcts on magnetic resonance imaging and normal or conditional TCDs, RR 0.70 (95% CI 0.23 to 2.13) (one trial, 196 participants, low-quality evidence). No deaths were reported in either trial. Long-term red blood cell transfusions may reduce the incidence of: acute chest syndrome, RR 0.24 (95% CI 0.12 to 0.49) (two trials, 326 participants, low-quality evidence); and painful crisis, RR 0.63 (95% CI 0.42 to 0.95) (two trials, 326 participants, low-quality evidence); and probably reduces the incidence of clinical stroke, RR 0.12 (95% CI 0.03 to 0.49) (two trials, 326 participants, moderate-quality evidence). Long-term red blood cell transfusions may improve quality of life in children with previous silent cerebral infarcts (difference estimate -0.54; 95% confidence interval -0.92 to -0.17; one trial; 166 participants), but may have no effect on cognitive function (least squares means: 1.7, 95% CI -1.1 to 4.4) (one trial, 166 participants, low-quality evidence). Transfusions continued versus transfusions halted: children and adolescents with normalised TCD velocities (79 participants; one trial) Continuing red blood cell transfusions may reduce the incidence of silent cerebral infarcts, RR 0.29 (95% CI 0.09 to 0.97 (low-quality evidence). We are very uncertain whether continuing red blood cell transfusions has any effect on all-cause mortality, Peto odds ratio (OR) 8.00 (95% CI 0.16 to 404.12); or clinical stroke, RR 0.22 (95% CI 0.01 to 4.35) (very low-quality evidence). The trial did not report: comparative numbers for SCD-related adverse events; quality of life; or cognitive function. Hydroxyurea and phlebotomy versus transfusions and chelation Primary prevention, children (121 participants; one trial) We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: silent cerebral infarcts (no infarcts); all-cause mortality (no deaths); risk of stroke (no strokes); or SCD-related complications, RR 1.52 (95% CI 0.58 to 4.02) (very low-quality evidence). Secondary prevention, children and adolescents with a history of stroke (133 participants; one trial) We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: silent cerebral infarcts, Peto OR 7.28 (95% CI 0.14 to 366.91); all-cause mortality, Peto OR 1.02 (95%CI 0.06 to 16.41); or clinical stroke, RR 14.78 (95% CI 0.86 to 253.66) (very low-quality evidence). Switching to hydroxyurea and phlebotomy may increase the risk of SCD-related complications, RR 3.10 (95% CI 1.42 to 6.75) (low-quality evidence). Neither trial reported on quality of life or cognitive function.

AUTHORS' CONCLUSIONS

We identified no trials for preventing silent cerebral infarcts in adults, or in children who do not have HbSS SCD. Long-term red blood cell transfusions may reduce the incidence of silent cerebral infarcts in children with abnormal TCD velocities, but may have little or no effect on children with normal TCD velocities. In children who are at higher risk of stroke and have not had previous long-term transfusions, long-term red blood cell transfusions probably reduce the risk of stroke, and other SCD-related complications (acute chest syndrome and painful crises). In children and adolescents at high risk of stroke whose TCD velocities have normalised, continuing red blood cell transfusions may reduce the risk of silent cerebral infarcts. No treatment duration threshold has been established for stopping transfusions. Switching to hydroxyurea with phlebotomy may increase the risk of silent cerebral infarcts and SCD-related serious adverse events in secondary stroke prevention. All other evidence in this review is of very low-quality.

Astragaloside IV alleviates ischemia reperfusion-induced apoptosis by inhibiting the activation of key factors in death receptor pathway and mitochondrial pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Apoptosis plays an important role in cerebral ischemia-reperfusion injury and triggers a series of pathological changes which may even be life-threatening. Astragaloside-IV (AS-IV), a natural compound extracted from Astragalus (Astragalus membranaceus (Fisch.) Bunge., Leguminosae, Huangqi in Chinese), showed neuroprotective effects in the study of cerebral ischemia-reperfusion injury. In this study we investigate the effects of AS-IV on apoptosis induced by transient cerebral ischemia and reperfusion in rats, as well as the associated regulatory factors.

METHODS

AS-IV was administrated to male Sprague-Dawley (SD) rats after transient cerebral ischemia and reperfusion surgery (12.5, 25, and 50 mg/kg, once per day, continued for 7 days after surgey). After seven days of continuous administration, neurological function, cerebral infarction volume, and pathological changes of brain tissue were detected. Fas, FasL, Caspase-8, Bax, and Bcl-2 mRNA levels were determined by real-time PCR. Caspase-8, Bid, Cytochrome C (Cyto C), cleaved Caspase-3 proteins were determined by western blot and immunohistochemistry was used to quantify Cyto C.

RESULTS

AS-IV significantly attenuated the neurological deficit in rats with ischemica-reperfusion injury, and reduced cerebral infarction and neuronal apoptosis. AS-IV inhibited the mRNA upregulation of Fas, FasL, Caspase-8, and Bax/Bcl-2. Furthermore, the protein level of apoptosis cytokines Caspase-8, Bid, cleaved Caspase-3 and Cyto C were also inhibited after ischemia reperfusion, suggesting that AS-IV might alleviate ischemia reperfusion-induced apoptosis by inhibiting the activation of key factors in death receptor pathway and mitochondrial pathway.

Hypothermia revisited: Impact of ischaemic duration and between experiment variability

To assess the true effect of novel therapies for ischaemic stroke, a positive control that can validate the experimental model and design is vital. Hypothermia may be a good candidate for such a positive control, given the convincing body of evidence from animal models of ischaemic stroke. Taking conditions under which substantial efficacy had been seen in a meta-analysis of hypothermia for focal ischaemia in animal models, we undertook three randomised and blinded studies examining the effect of hypothermia induced immediately following the onset of middle cerebral artery occlusion on infarct volume in rats (n = 15, 23, 264). Hypothermia to a depth of 33℃ and maintained for 130 min significantly reduced infarct volume compared to normothermia treatment (by 27-63%) and depended on ischaemic duration (F(3,244) = 21.242, p < 0.05). However, the protective effect varied across experiments with differences in both the size of the infarct observed in normothermic controls and the time to reach target temperature. Our results highlight the need for sample size and power calculations to take into account variations between individual experiments requiring induction of focal ischaemia.

Effect of Cerebral Embolic Protection Devices on CNS Infarction in Surgical Aortic Valve Replacement: A Randomized Clinical Trial

IMPORTANCE

Stroke is a major complication of surgical aortic valve replacement (SAVR).

OBJECTIVE

To determine the efficacy and adverse effects of cerebral embolic protection devices in reducing ischemic central nervous system (CNS) injury during SAVR.

DESIGN, SETTING, AND PARTICIPANTS

A randomized clinical trial of patients with calcific aortic stenosis undergoing SAVR at 18 North American centers between March 2015 and July 2016. The end of follow-up was December 2016.

INTERVENTIONS

Use of 1 of 2 cerebral embolic protection devices (n = 118 for suction-based extraction and n = 133 for intra-aortic filtration device) vs a standard aortic cannula (control; n = 132) at the time of SAVR.

MAIN OUTCOMES AND MEASURES

The primary end point was freedom from clinical or radiographic CNS infarction at 7 days (± 3 days) after the procedure. Secondary end points included a composite of mortality, clinical ischemic stroke, and acute kidney injury within 30 days after surgery; delirium; mortality; serious adverse events; and neurocognition.

RESULTS

Among 383 randomized patients (mean age, 73.9 years; 38.4% women; 368 [96.1%] completed the trial), the rate of freedom from CNS infarction at 7 days was 32.0% with suction-based extraction vs 33.3% with control (between-group difference, -1.3%; 95% CI, -13.8% to 11.2%) and 25.6% with intra-aortic filtration vs 32.4% with control (between-group difference, -6.9%; 95% CI, -17.9% to 4.2%). The 30-day composite end point was not significantly different between suction-based extraction and control (21.4% vs 24.2%, respectively; between-group difference, -2.8% [95% CI, -13.5% to 7.9%]) nor between intra-aortic filtration and control (33.3% vs 23.7%; between-group difference, 9.7% [95% CI, -1.2% to 20.5%]). There were no significant differences in mortality (3.4% for suction-based extraction vs 1.7% for control; and 2.3% for intra-aortic filtration vs 1.5% for control) or clinical stroke (5.1% for suction-based extraction vs 5.8% for control; and 8.3% for intra-aortic filtration vs 6.1% for control). Delirium at postoperative day 7 was 6.3% for suction-based extraction vs 15.3% for control (between-group difference, -9.1%; 95% CI, -17.1% to -1.0%) and 8.1% for intra-aortic filtration vs 15.6% for control (between-group difference, -7.4%; 95% CI, -15.5% to 0.6%). Mortality and overall serious adverse events at 90 days were not significantly different across groups. Patients in the intra-aortic filtration group vs patients in the control group experienced significantly more acute kidney injury events (14 vs 4, respectively; P = .02) and cardiac arrhythmias (57 vs 30; P = .004).

CONCLUSIONS AND RELEVANCE

Among patients undergoing SAVR, cerebral embolic protection devices compared with a standard aortic cannula did not significantly reduce the risk of CNS infarction at 7 days. Potential benefits for reduction in delirium, cognition, and symptomatic stroke merit larger trials with longer follow-up.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02389894.

Interventions for preventing silent cerebral infarcts in people with sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta globin) genes. SCD can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Silent cerebral infarcts are the commonest neurological complication in children and probably adults with SCD. Silent cerebral infarcts also affect academic performance, increase cognitive deficits and may lower intelligence quotient.

OBJECTIVES

To assess the effectiveness of interventions to reduce or prevent silent cerebral infarcts in people with SCD.

SEARCH METHODS

We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 19 September 2016. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register: 06 October 2016.

SELECTION CRITERIA

Randomised controlled trials comparing interventions to prevent silent cerebral infarcts in people with SCD. There were no restrictions by outcomes examined, language or publication status.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

We included five trials (660 children or adolescents) published between 1998 and 2016. Four of the five trials were terminated early. The vast majority of participants had the haemoglobin (Hb)SS form of SCD. One trial focused on preventing silent cerebral infarcts or stroke; three trials were for primary stroke prevention and one trial dealt with secondary stroke prevention.Three trials compared the use of regular long-term red blood cell transfusions to standard care. Two of these trials included children with no previous long-term transfusions: one in children with normal transcranial doppler (TCD) velocities; and one in children with abnormal TCD velocities. The third trial included children and adolescents on long-term transfusion.Two trials compared the drug hydroxyurea and phlebotomy to long-term transfusions and iron chelation therapy: one in primary prevention (children), and one in secondary prevention (children and adolescents).The quality of the evidence was moderate to very low across different outcomes according to GRADE methodology. This was due to trials being at high risk of bias because they were unblinded; indirectness (available evidence was only for children with HbSS); and imprecise outcome estimates. Long-term red blood cell transfusions versus standard care Children with no previous long-term transfusions and higher risk of stroke (abnormal TCD velocities or previous history of silent cerebral infarcts) Long-term red blood cell transfusions may reduce the incidence of silent cerebral infarcts in children with abnormal TCD velocities, risk ratio (RR) 0.11 (95% confidence interval (CI) 0.02 to 0.86) (one trial, 124 participants, low-quality evidence); but make little or no difference to the incidence of silent cerebral infarcts in children with previous silent cerebral infarcts on magnetic resonance imaging and normal or conditional TCDs, RR 0.70 (95% CI 0.23 to 2.13) (one trial, 196 participants, low-quality evidence).No deaths were reported in either trial.Long-term red blood cell transfusions may reduce the incidence of: acute chest syndrome, RR 0.24 (95% CI 0.12 to 0.49) (two trials, 326 participants, low-quality evidence); and painful crisis, RR 0.63 (95% CI 0.42 to 0.95) (two trials, 326 participants, low-quality evidence); and probably reduces the incidence of clinical stroke, RR 0.12 (95% CI 0.03 to 0.49) (two trials, 326 participants, moderate-quality evidence).Long-term red blood cell transfusions may improve quality of life in children with previous silent cerebral infarcts (difference estimate -0.54; 95% confidence interval -0.92 to -0.17; one trial; 166 participants), but may have no effect on cognitive function (least squares means: 1.7, 95% CI -1.1 to 4.4) (one trial, 166 participants, low-quality evidence). Transfusions continued versus transfusions halted: children and adolescents with normalised TCD velocities (79 participants; one trial)Continuing red blood cell transfusions may reduce the incidence of silent cerebral infarcts, RR 0.29 (95% CI 0.09 to 0.97 (low-quality evidence).We are very uncertain whether continuing red blood cell transfusions has any effect on all-cause mortality, Peto odds ratio (OR) 8.00 (95% CI 0.16 to 404.12); or clinical stroke, RR 0.22 (95% CI 0.01 to 4.35) (very low-quality evidence).The trial did not report: comparative numbers for SCD-related adverse events; quality of life; or cognitive function. Hydroxyurea and phlebotomy versus transfusions and chelation Primary prevention, children (121 participants; one trial)We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: silent cerebral infarcts (no infarcts); all-cause mortality (no deaths); risk of stroke (no strokes); or SCD-related complications, RR 1.52 (95% CI 0.58 to 4.02) (very low-quality evidence). Secondary prevention, children and adolescents with a history of stroke (133 participants; one trial)We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: silent cerebral infarcts, Peto OR 7.28 (95% CI 0.14 to 366.91); all-cause mortality, Peto OR 1.02 (95%CI 0.06 to 16.41); or clinical stroke, RR 14.78 (95% CI 0.86 to 253.66) (very low-quality evidence).Switching to hydroxyurea and phlebotomy may increase the risk of SCD-related complications, RR 3.10 (95% CI 1.42 to 6.75) (low-quality evidence).Neither trial reported on quality of life or cognitive function.

AUTHORS' CONCLUSIONS

We identified no trials for preventing silent cerebral infarcts in adults, or in children who do not have HbSS SCD.Long-term red blood cell transfusions may reduce the incidence of silent cerebral infarcts in children with abnormal TCD velocities, but may have little or no effect on children with normal TCD velocities. In children who are at higher risk of stroke and have not had previous long-term transfusions, long-term red blood cell transfusions probably reduce the risk of stroke, and other SCD-related complications (acute chest syndrome and painful crises).In children and adolescents at high risk of stroke whose TCD velocities have normalised, continuing red blood cell transfusions may reduce the risk of silent cerebral infarcts. No treatment duration threshold has been established for stopping transfusions.Switching to hydroxyurea with phlebotomy may increase the risk of silent cerebral infarcts and SCD-related serious adverse events in secondary stroke prevention.All other evidence in this review is of very low-quality.

Ibudilast: a non‑selective phosphodiesterase inhibitor in brain disorders

Ibudilast (IBD) is a non‑selective (3, 4, 10, 11) phosphodiesterase (PDE) inhibitor, used mainly as a bronchodilator for the treatment of bronchial asthma. PDE play a central role in cellular function (e.g. differentiation, synaptic plasticity and inflammatory response) by metabolizing cyclic nucleotides. The results from preclinical and clinical studies indicate that IBD has a broader range of action through suppression of pro‑inflammatory cytokines (IL‑6, IL‑1β, TNF‑α), toll‑like receptor 4 blockade (TLR‑4), inhibition of a macrophage migration inhibitory factor (MIF), up‑regulation the anti‑inflammatory cytokine (IL‑10), and promotion of neurotrophic factors (GDNF, NGF, NT‑4). Recent data indicate that the efficacy of IBD appears to be independent from PDE inhibition activity and rather linked to glial activity attenuation. Additional advantages of IBD, such as crossing the blood-brain barrier, good tolerance and activity by oral administration, makes it a promising therapeutic candidate for treating neuroinflammatory conditions, where the currently available treatment remains unsatisfying due to poor tolerability and/or sub‑optimal efficacy. IBD has no direct receptor affinity with exemption of some undefined effect on adenosine receptors that makes the drug devoid of its receptors‑mediated adverse effects. Current article provides an overview of the pharmacology of IBD with a focus on preclinical and clinical data supporting its potential neuroprotective benefits for neurological conditions, including multiple sclerosis, neuropathic pain, medication overuse headache, stroke, opioid, alcohol and methamphetamine abuse.

Efficacy of Urtoxazumab (TMA-15 Humanized Monoclonal Antibody Specific for Shiga Toxin 2) Against Post-Diarrheal Neurological Sequelae Caused by Escherichia coli O157:H7 Infection in the Neonatal Gnotobiotic Piglet Model

Enterohemorrhagic Escherichia coli (EHEC) is the most common cause of hemorrhagic colitis and hemolytic uremic syndrome in human patients, with brain damage and dysfunction the main cause of acute death. We evaluated the efficacy of urtoxazumab (TMA-15, Teijin Pharma Limited), a humanized monoclonal antibody against Shiga toxin (Stx) 2 for the prevention of brain damage, dysfunction, and death in a piglet EHEC infection model. Forty-five neonatal gnotobiotic piglets were inoculated orally with 3 × 10⁹ colony-forming units of EHEC O157:H7 strain EDL933 (Stx1⁺, Stx2⁺) when 22–24 h old. At 24 h post-inoculation, piglets were intraperitoneally administered placebo or TMA-15 (0.3, 1.0 or 3.0 mg/kg body weight). Compared to placebo (n = 10), TMA-15 (n = 35) yielded a significantly greater probability of survival, length of survival, and weight gain (p <0.05). The efficacy of TMA-15 against brain lesions and death was 62.9% (p = 0.0004) and 71.4% (p = 0.0004), respectively. These results suggest that TMA-15 may potentially prevent or reduce vascular necrosis and infarction of the brain attributable to Stx2 in human patients acutely infected with EHEC. However, we do not infer that TMA-15 treatment will completely protect human patients infected with EHEC O157:H7 strains that produce both Stx1 and Stx2.

Aortic Arch Atheroma: Stroke Reduction in Cardiac Surgical Patients

Cardiac surgery is increasingly performed on elderly patients with extensive coronary artery abnormalities who have impaired left ventricular function, decreased physiologic reserve, and multiple comorbid conditions. Considerable numbers of these patients develop perioperative neurologic complications ranging from subtle cognitive dysfunction to more evident postoperative confusion, delirium, and, less commonly, clinically apparent stroke. Magnetic resonance imaging studies have elucidated that a considerable number of patients have new ischemic brain infarcts, particularly after conventional coronary artery bypass graft surgery. Mechanisms of cerebral injury during and after cardiac surgery are discussed. Intraoperative transesophageal echocardiography and epiaortic scanning for detection of atheromatous disease of the proximal thoracic aorta is paramount in identifying patients at high risk from neurologic injury. It is important to recognize that our efforts to minimize neurologic injury should not be limited to the intraoperative period. Particular efforts should be directed to temperature management, glycemia control, and pharmacologic neuroprotection extending into the postoperative period. Preoperative magnetic resonance angiography may be of value for screening patients with significant atheroma of the proximal thoracic aorta. It is likely that for patients with no significant atheromatous disease, conventional coronary artery revascularization is the most effective long-term strategy, whereas patients with atheromatous thoracic aorta may be better managed with beating heart surgery, hybrid techniques, or medical therapy alone. Patient stratification based on the aortic atheromatic burden should be addressed in future trials designed to tailor treatment strategies to improve long-term outcomes of coronary heart disease and reduce the risks of perioperative neurologic injury.

Effect of apixaban on brain infarction and microbleeds: AVERROES-MRI assessment study

BACKGROUND

Clinical and subclinical (covert) stroke is a cause of cognitive loss and functional impairment. In the AVERROES trial, we performed serial brain magnetic resonance imaging (MRI) scans in a subgroup to explore the effect of apixaban, compared with aspirin, on clinical and covert brain infarction and on microbleeds in patients with atrial fibrillation.

METHODS

We performed brain MRI (T1, T2, fluid-attenuated inversion recovery, and T2* gradient echo sequences) in 1,180 at baseline and in 931 participants at follow-up. Mean interval from baseline to follow-up MRI scans was 1.0 year. The primary outcome was a composite of clinical ischemic stroke and covert embolic pattern infarction (defined as infarction >1.5 cm, cortical-based infarction, or new multiterritory infarction). Secondary outcomes included new MRI-detected brain infarcts and microbleeds and change in white matter hyperintensities.

RESULTS

Baseline MRI scans revealed brain infarct(s) in 26.2% and microbleed(s) in 10.5%. The rate of the primary outcomes was 2.0% in the apixaban group and 3.3% in the aspirin group (hazard ratio [HR] 0.55; 0.27-1.14) from baseline to follow-up MRI scan (mean duration of follow-up: 1 year). In those who completed baseline and follow-up MRI scans, the rate of new infarction detected on MRI was 2.5% in the apixaban group and 2.2% in the aspirin group (HR 1.09; 0.47-2.52), but new infarcts were smaller in the apixaban group (P = .03). There was no difference in proportion with new microbleeds on follow-up MRI (HR 0.92; 0.53-1.60) between treatment groups.

CONCLUSIONS

Apixaban treatment was associated with a nonsignificant trend toward reduction in the composite of clinical ischemic stroke and covert embolic-pattern infarction and did not increase the number of microbleeds in patients with atrial fibrillation compared with aspirin.

Sonolysis in Prevention of Brain Infarction During Cardiac Surgery (SONORESCUE): Randomized, Controlled Trial

Here, we examined whether intraoperative sonolysis can alter the risk of new ischemic lesions in the insonated brain artery territory during coronary artery bypass grafting (CABG) or valve surgery.Silent brain ischemic lesions could be detected in as many as two-thirds of patients after CABG or valve surgery.Patients indicated for CABG or valve surgery were allocated randomly to sonolysis (60 patients, 37 males; mean age, 65.3 years) of the right middle cerebral artery (MCA) during cardiac surgery and control group (60 patients, 37 males; mean age, 65.3 years). Neurologic examination, cognitive function tests, and brain magnetic resonance imaging (MRI) were conducted before intervention as well as 24 to 72 hours and 30 days after surgery.New ischemic lesions on control diffusion-weighted MRI in the insonated MCA territory ≥0.5 mL were significantly less frequent in the sonolysis group than in the control group (13.3% vs 26.7%, P = 0.109). The sonolysis group exhibited significantly reduced median volume of new brain ischemic lesions (P = 0.026). Stenosis of the internal carotid artery ≥50% and smoking were independent predictors of new brain ischemic lesions ≥0.5 mL (odds ratio = 5.685 [1.272-25.409], P = 0.023 and 4.698 [1.092-20.208], P = 0.038, respectively). Stroke or transient ischemic attack occurred only in 2 control patients (P = 0.496). No significant differences were found in scores for postintervention cognitive tests (P > 0.05).This study provides class-II evidence that sonolysis during CABG or valve surgery reduces the risk of larger, new ischemic lesions in the brain.www.clinicaltrials.gov (NCT01591018).

Poststroke Inflammasome Expression and Regulation in the Peri-Infarct Area by Gonadal Steroids after Transient Focal Ischemia in the Rat Brain

CNS ischemia results in locally confined and rapid tissue damage accompanied by a loss of neurons and their circuits. Early and time-delayed inflammatory responses are critical variables determining the extent of neural disintegration and regeneration. Inflammasomes are vital effectors in innate immunity. Their activation in brain-intrinsic immune cells contributes to ischemia-related brain damage. The steroids 17β-estradiol (E2) and progesterone (P) are neuroprotective and anti-inflammatory. Using a transient focal rat ischemic model, we evaluated the time response of different inflammasomes in the peri-infarct zone from the early to late phases after poststroke ischemia. We show that the different inflammasome complexes reveal a specific time-oriented sequential expression pattern with a maximum at approximately 24 h after the infarct. Within the limits of antibody availability, immunofluorescence labeling demonstrated that microglia and neurons are major sources of the locally activated inflammasomes NOD-like receptor protein-3 (NLRP3) and associated speck-like protein (ASC), respectively. E2 and P given for 24 h immediately after ischemia onset reduced hypoxia-induced mRNA expression of the inflammasomes NLRC4, AIM2 and ASC, and decreased the protein levels of ASC and NLRP3. In addition, mRNA protein levels of the cytokines interleukin-1β (IL1β), IL18 and TNFα were reduced by the steroids. The findings provide for the first time a detailed flow chart of hypoxia-driven inflammasome regulation in the peri-infarct cerebral cortex. Further, we demonstrate that E2 and P alleviate the expression of certain inflammasome components, sometimes in a hormone-specific way. Besides directly regulating other cellular neuroprotective pathways, the control of inflammasomes by these steroids might contribute to its neuroprotective potency.

Testosterone enhances functional recovery after stroke through promotion of antioxidant defenses, BDNF levels and neurogenesis in male rats

It is reported that circulating testosterone levels decrease after cerebral ischemia. The aim of this study was to evaluate the effects of testosterone on oxidative stress, brain-derived neurotrophic factor (BDNF) levels, neurogenesis, histological damage and sensorimotor recovery in a castrated male rat model of focal cerebral ischemia. Animals were divided into four groups. For all animals, castrations were conducted 7 days before transient middle cerebral artery occlusion (MCAO) was done and cerebral ischemia was induced. The first group served as sham. Second was MCAO group and received vehicle only, third was MCAO group that was post-treated with testosterone and the fourth was MCAO group post-treated with testosterone and flutamide. Treatment only with testosterone significantly weakened oxidative stress and increased BDNF levels and sensorimotor recovery during a 10 days period. Rats receiving testosterone demonstrated a significant reduction in infarct volume and a significant increase in neurogenesis on 10th day after focal cerebral ischemia. Our results for the first time showed a potential advantageous effect of testosterone after cerebral ischemia in male rats, which was probably mediated by promoting antioxidant defenses, BDNF levels and neurogenesis.

Acute neurovascular unit protection by simvastatin in transient cerebral ischemia

Acute vascular- and neuroprotective effects of simvastatin were evaluated in a rat model of transient, focal cerebral ischemia. Male, Wistar rats (n=12) underwent transient middle cerebral artery (MCA) occlusion for 3 hours followed by 3 hours of reperfusion. After 30 minutes of MCA occlusion, four rats each were subcutaneously injected with either 20 or 40 mg/kg of simvastatin. At the end of 3 hours of reperfusion, tissue injury and blood-brain barrier (BBB) opening were quantified by histology and [(14)C]-alpha-aminoisobutyric acid (AIB)-based quantitative autoradiography (QAR), respectively. Compared with untreated rats, those treated with simvastatin (20 mg/kg) had reduced volumes of AIB leakage, tissue pallor and distribution space for AIB (p<0.05). No additional effects were seen with the higher drug dose (40 mg/kg). These data suggest that the acute neuroprotective effects of statins are in part owing to attenuation of stroke-induced changes in BBB permeability.

Protective effects of a novel herbal decoction on focal cerebral ischemia in a rodent model

BACKGROUND

Herbs have been used to treat stroke and coma patient in traditional Korean medicine (TKM). The novel decoction, Guhpoongchungsimhwan (GCH), was developed on the basis of clinical data and TKM theory.

METHODS

We examined the neuroprotective effect of GCH on cerebral ischemia. The middle cerebral artery occlusion (MCAO) model was used to produce cerebral ischemia in Sprague-Dawley rats. Subjects were treated with GCH (50 or 200 mg/kg) or vehicle alone (controls) 0 and 2 hours after MCAO. The functional status was tested 24 hours after MCAO by neurological examination (clinical score) and by series of motor function tasks (foot placement and parallel bar crossing).

RESULTS

The infarct volume was determined by 2,3,5-triphenyltetrazolium chloride staining 24 hours after surgery, and the expression of cyclooxygenase-2 was determined by immunohistochemistry. The clinical score of the GCH-treated group (200 mg/kg) was significantly lower than that of the control group (p<0.05), indicating fewer neurological deficits. The impairment of motor functions induced by MCAO was significantly reduced by the administration of GCH (p<0.05). The infarct volume was significantly smaller in the GCH-treated group (203.1 +/- 40.2 mm(3), p<0.05), as compared to the control group (377.8 +/- 32.6 mm(3)). The level of motor function in the GCH-treated group was associated with reduced infarct volume. In the analysis of immunohistochemistry, GCH treatment markedly inhibited the ischemia-induced expression of PTGS2 (prostaglandin-endoperoxidase synthase 2) or cyclooxygenase 2 (COX2), which plays an important role in ischemic neuronal cell death.

CONCLUSION

The results showed that GCH reduced the infarct size and the functional deficits in MCAO rats.

Neuroprotection against transient cerebral ischemia by exercise pre-conditioning in rats

There is increasing evidence that physical activity is associated with decreased stroke risk and incidence. The purpose of this study was to determine whether increased levels of physical activity could reduce brain damage in rats subjected to transient or permanent middle cerebral artery (MCA) occlusion. Adult male Sprague-Dawley rats (three months old, n=36) exercised on a treadmill, which required repetitive locomotor movement, for 30 min each day for three weeks. Then, using an intraluminal filament, stroke was induced by either 2-h MCA occlusion followed by two days of reperfusion or by MCA occlusion for two days without reperfusion. Brain damage was determined by evaluating neurologic deficits and brain infarction. In rat with transient MCA occlusion, pre-ischemic motor activity significantly (p<0.01) reduced neurologic deficits and infarct volume in the frontoparietal cortex and the dorsolateral striatum. In contrast, the same exercise procedure did not produce neuroprotection in the permanently MCA-occluded stroke. In addition to decreasing stroke risk and incidence, physical activity also reduces brain damage after stroke. Although we cannot completely rule out a neuroprotective effect on ischemic episode, our study suggests that a major neuroprotection is conferred during reperfusion for rats that have undergone exercise pre-conditioning. This exercise-induced endogenous neuroprotection may be an effective strategy to ameliorate ischemia/reperfusion brain injury from stroke.

Neurodegeneration after transient brain ischemia in aged mice: beneficial effects of bilobalide

Bilobalide, an active constituent of Ginkgo biloba, has neuroprotective properties in experimental stroke models, but nearly all published studies were carried out in young animals. As ischemic strokes in humans are much more frequent in old age, we investigated bilobalide's effects in aged mice (age 18-22 month) using a model of transient ischemia induced by occlusion of the middle cerebral artery (MCAO) for 60 min. When bilobalide was administered locally into the striatum via microdialysis, a significant reduction of infarct size by almost 70% was observed. Concomitantly, the extensive, twelve-fold increase of extracellular glutamate which was observed in untreated animals was strongly reduced during the infusion of bilobalide. Glucose levels, in contrast, were not affected by bilobalide. In further experiments, bilobalide was given as an intraperitoneal injection (10/mg/kg) 1h before MCAO onset. ATP levels (measured in brain homogenates) were significantly reduced by transient MCAO but pretreatment with bilobalide prevented this loss. In ex vivo experiments with isolated mitochondria from aged mice, we found that the activity of the mitochondrial respiratory chain was only slightly impaired after 60 min of ischemia, and bilobalide showed no benefit in this experiment. However, aged mitochondria proved to be very sensitive to calcium-induced swelling which was significantly increased after ischemia. In this assay, pretreatment with bilobalide lowered the extent of swelling nearly to control levels. In behavioural tests, pretreatment of aged mice with bilobalide significantly improved the outcome in the Rotarod and the Corner test. In conclusion, aged mice show some differences in their response to transient ischemia when compared with young mice. Bilobalide has prominent neuroprotective properties in mice of all ages.

Glucocorticoid signaling in myeloid cells worsens acute CNS injury and inflammation

Glucocorticoid stress hormones (GCs) are well known for being anti-inflammatory, but some reports suggest that GCs can also augment aspects of inflammation during acute brain injury. Because the GC receptor (GR) is ubiquitously expressed throughout the brain, it is difficult to know which cell types might mediate these unusual "proinflammatory" GC actions. We examined this with cell type-specific deletion or overexpression of GR in mice experiencing seizure or ischemia. Counter to their classical anti-inflammatory actions, GR signaling in myeloid cells increased Iba-1 and CD68 staining as well as nuclear p65 levels in the injured tissue. GCs also reduced levels of occludin, claudin 5, and caveolin 1, proteins central to blood-brain-barrier integrity; these effects required GR in endothelial cells. Finally, GCs compromised neuron survival, an effect mediated by GR in myeloid and endothelial cells to a greater extent than by neuronal GR.

Ursolic acid promotes the neuroprotection by activating Nrf2 pathway after cerebral ischemia in mice

BACKGROUND

Oxidative and inflammatory damages have been suggested to play an important role in cerebral ischemic pathogenesis, and provide promising therapeutic strategies for stroke. Nuclear factor-erythroid 2-related factor 2 (Nrf2), a pleiotropic transcription factor, has been shown to play a key role in protecting cells against oxidative injury in cerebral ischemia. In this study, we demonstrated the hypothesis that ursolic acid (UA), a natural pentacyclic triterpenoid acid, isolated from edible plants in the Oleaceae family, a well-known anti-oxidative and anti-inflammatory reagent, protects the brain against ischemic injury by activating the Nrf2 pathway.

METHODS

Nrf2(-/-) and wild-type (WT) mice were induced into focal cerebral ischemia by transient middle cerebral artery occlusion (MCAO), and received UA treatment immediately after MCAO. The behavioral dysfunction, infarct size, and the expression of Nrf2, HO-1 and inflammatory factors (TLR4 and NF-κB) in ischemic brain were measured at 24h after stroke.

RESULTS

UA treatment significantly improved neurological deficit and reduced infarct size in WT mice after MCAO. Administration of UA also decreased the product of lipid peroxidation, promoted the activation of Nrf2 pathway and decreased the expression of TLR4 and NF-KB after stroke in WT mice. However, Nrf2(-/-) mice demonstrated more severe neurologic deficits, infarct size and inflammatory damage after MCAO, and did not benefit from the protective effect of UA.

CONCLUSION

The results indicated that UA protected the brain against ischemic injury in mice by anti-oxidative and anti-inflammatory effects after MCAO. Activation of the Nrf2 pathway contributes to the neuroprotective effects induced by UA in cerebral ischemia.

Endovascular stenting of symptomatic innominate artery stenosis under distal balloon protection of the internal carotid and vertebral artery for cerebral protection: a technical case report

The use of cerebral protection devices in endovascular treatment for innominate artery (IA) stenosis is not well established. We describe a novel technique for cerebral protection during endovascular stenting of symptomatic IA stenosis. An 82-year-old man presented with acutely scattered brain infarction by artery-to-artery embolism due to IA stenosis. Endovascular treatment for symptomatic IA stenosis was planned to prevent recurrent attacks. Endovascular stenting for IA stenosis via the right femoral artery approach was performed under simultaneous distal balloon protection of the right internal carotid artery (ICA) and vertebral artery (VA) via the right brachial artery approach. Successful treatment of symptomatic IA stenosis was achieved with no complications. The technique with simultaneous distal balloon protection of the ICA and VA provided excellent cerebral protection in stenting of IA stenosis.

Neonatal testosterone exposure protects adult male rats from stroke

BACKGROUND

Men have a higher stroke incidence compared to women until advanced age. The contribution of hormones to these sex differences has been extensively debated. In experimental stroke, estradiol is neuroprotective, whereas androgens are detrimental. However, prior studies have only examined the effects of acute treatment paradigms; therefore, the timing and mechanism by which ischemic sexual dimorphism arises are unknown.

METHODS

The effects of exogenous neonatal androgen exposure on subsequent injury induced by middle cerebral artery occlusion in adulthood in male rats were examined. Rats were administered vehicle (oil), testosterone propionate (TP) or the non-aromatizable androgen dihydrotestosterone (DHT) for 5 days after birth. At 3 months of age, a focal stroke was induced.

RESULTS

Testosterone-treated rats (but not DHT-treated animals) had decreased infarct volumes (20 vs. 33%, p < 0.05) as well as increased estradiol levels (39.4 vs. 18.6 pg/ml, p < 0.0001) compared to oil-treated animals. TP-injected males had increased testicular aromatase (P450arom) levels (3.6 vs. 0.2 ng/ml, p < 0.0001) compared to oil-treated males. The level of X-linked inhibitor of apoptosis, the primary endogenous inhibitor of caspase-induced apoptosis, was increased in TP-treated rats compared with the oil-treated males.

CONCLUSIONS

Neonatal exposure to exogenous testosterone upregulates testicular aromatase expression in male rats and leads to adult neuroprotection secondary to changes in serum estradiol levels and cell death proteins. This study suggests that early exposure to gonadal hormones can have dramatic effects on the response to adult cerebrovascular injury.

Cannabinoid receptor subtypes 1 and 2 mediate long-lasting neuroprotection and improve motor behavior deficits after transient focal cerebral ischemia

The endocannabinoid system is crucially involved in the regulation of brain activity and inflammation. We have investigated the localization of cannabinoid CB1 and CB2 receptors in adult rat brains before and after focal cerebral ischemia due to endothelin-induced transient occlusion of the middle cerebral artery (eMCAO). Using immunohistochemistry, both receptor subtypes were identified in cortical neurons. After eMCAO, neuronal cell death was accompanied by reduced neuronal CB1 and CB2 receptor-linked immunofluorescence. In parallel, CB1 receptor was found in activated microglia/macrophages 3 days post eMCAO and in astroglia cells at days 3 and 7. CB2 receptor labeling was identified in activated microglia/macrophages or astroglia 3 and 7d ays post ischemia, respectively. In addition, immune competent CD45-positive cells were characterized by pronounced CB2 receptor staining 3 and 7 days post eMCAO. KN38-72717, a potent and selective CB1 and CB2 receptor agonist, revealed a significant, dose-dependent and long-lasting reduction of cortical lesion sizes due to eMCAO, when applied consecutively before, during and after eMCAO. In addition, severe motor deficits of animals suffering from eMCAO were significantly improved by KN38-7271. KN38-7271 remained effective, even if its application was delayed up to 6h post eMCAO. Finally, we show that the endocannabinoid system assembles a comprehensive machinery to defend the brain against the devastating consequences of cerebral ischemia. In summary, this study underlines the therapeutic potential of CB1 and/or CB2 receptor agonists against neurodegenerative diseases or injuries involving acute or chronic imbalances of cerebral blood flow and energy consumption.

Neurogenic neuroprotection: clinical perspectives

Neurogenic neuroprotection is a promising approach for treating patients with ischemic brain lesions. In rats, stimulation of the deep brain nuclei has been shown to reduce the volume of focal infarction. In this context, protection of neural tissue can be a rapid intervention that has a relatively long-lasting effect, making fastigial nucleus stimulation (FNS) a potentially valuable method for clinical application. Although the mechanisms of neuroprotection induced by FNS remain partially unclear, important data have been presented in the last two decades. A 1-h electrical FNS reduced, by 59%, infarctions triggered by permanent occlusion of the middle cerebral artery in Fisher rats. The acute effect of electrical FNS is likely mediated by a prolonged opening of potassium channels, and the sustained effect appears to be linked to inhibition of the apoptotic cascade. A better understanding of the neuronal circuitry underlying neurogenic neuroprotection may contribute to improving neurological outcomes in ischemic brain insults.

Global brain ischemia in Mongolian gerbils: assessing the level of anastomosis in the cerebral circle of Willis

The Mongolian gerbil has been widely used as a global brain ischemia model because of its incomplete cerebral circle of Willis. However, the inter-individual anatomic variability of this vascular structure interferes with the reliability of the model. The aim of this work was to introduce modifications to the protocol of global brain ischemia experiments in Mongolian gerbils in an attempt to increase the reliability and usefulness of this model. Our study focused on the assessment of the level of anastomosis of the cerebral circle of Willis in order to evaluate its contribution to clinicopathological outcomes in this model. Sham-operated, Ischemic, and Ischemic + Hypothermia animals were subjected to a 15-minute occlusion of the common carotid arteries. Transcardiac perfusion with bromophenol blue / gelatin solution was performed 72 hours after ischemia. Brains were processed for anatomopathological analysis. Tissue damage was observed in the hippocampus, caudate-putamen nucleus, neocortex, and thalamic nuclei of animals from the Ischemic group. The circles of Willis of the Sham-operated animals showed bilateral (38 percent), unilateral (48 percent) or no posterior communicating arteries (14 percent). A negative correlation between infarct volume and the level of anastomosis was revealed for the Ischemic, but not for the Ischemic + Hypothermia group. Additionally, Analysis of covariance (ANCOVA) was performed to assess the contribution of the level of anastomosis to the clinicopathological outcomes. It was confirmed that the infarct volume decreased in the Ischemic + Hypothermia group when compared to the Ischemic group. Since the level of anastomosis cannot be predicted, this variable should necessarily be considered when analyzing the results of global brain ischemia in Mongolian gerbils.

Ginsenoside rd in experimental stroke: superior neuroprotective efficacy with a wide therapeutic window

Ginsenoside Rd (Rd), one of the main active ingredients in Panax ginseng, has been demonstrated to protect against ischemic cerebral damage in vitro and in vivo. In this study, we aimed to further define the preclinical characteristics of Rd. We show that Rd passes the intact blood-brain barrier and exerts protection in both transient and permanent middle cerebral artery occlusion (MCAO) in rats. In the dose-response study, Rd (10-50 mg/Kg) significantly reduced the infarct volume on postoperative days (PODs) 1, 3, and 7. This protection was associated with an improved neurological outcome for as many as 6 weeks after transient MCAO, as assessed by modified neurological severity score, modified sticky-tape test, and corner test. For comparison, Rd was significantly more effective than edaravone and slightly more effective than N-tert-butyl-alpha-phenylnitrone (PBN). In the therapeutic window study, Rd exhibited remarkable neuroprotection, even when administered for as many as 4 h after the recirculation of transient MCAO or after the onset of permanent MCAO. Furthermore, in female rats or 16-month-old male rats, the salutary effects of Rd were also observed. These findings suggest Rd is a promising neuroprotectant and provide support for future clinical studies to confirm whether Rd is beneficial in ischemic stroke.

Ischemia-induced changes in glucagon-like peptide-1 receptor and neuroprotective effect of its agonist, exendin-4, in experimental transient cerebral ischemia

Glucagon-like peptide-1 receptor (GLP-1R) protects against neuronal damages in the brain. In the present study, ischemia-induced changes in GLP-1R immunoreactivity in the gerbil hippocampal CA1 region were evaluated after transient cerebral ischemia; in addition, the neuroprotective effect of the GLP-1R agonist exendin-4 (EX-4) against ischemic damage was studied. GLP-1R immunoreactivity and its protein levels in the ischemic CA1 region were highest at 1 day after ischemia/reperfusion (I/R). At 4 days after I/R, GLP-1R immunoreactivity was hardly detected in CA1 pyramidal neurons, and its protein level was lowest. GLP-1R protein level was increased again at 10 days after I/R, and GLP-1R immunoreactivity was found in astrocytes and GABAergic interneurons. In addition, EX-4 treatment attenuated ischemia-induced hyperactivity, neuronal damage, and microglial activation in the ischemic CA1 region in a dose-dependent manner. EX-4 treatment also induced the elevation of GLP-1R immunoreactivity and protein levels in the ischemic CA1 region. These results indicate that GLP-1R is altered in the ischemic region after an ischemic insult and that EX-4 protects against ischemia-induced neuronal death possibly by increasing GLP-1R expression and attenuating microglial activation against transient cerebral ischemic damage.

Sigma-1 receptor ligand PRE-084 reduced infarct volume, neurological deficits, pro-inflammatory cytokines and enhanced anti-inflammatory cytokines after embolic stroke in rats

Sigma receptor agonists have been found to provide potent neuroprotection in rats and mice. This neuroprotection is thought to be mediated through anti-excitotoxic mechanisms. Neuroprotective and immune modulatory effects of sigma ligands have not been investigated in embolic stroke. In the present study, rats were subjected to embolic stroke or sham stroke and were treated with the sigma-1 receptor agonist PRE-084 (5mg/kg i.p.) or saline vehicle 3 and 24h after stroke. Infarct volume and behavioural tests were conducted, and cytokine levels (ILs-1α and β, IL-2, IL-4, IL-6, IL-10, GM-CSF and TNF-α) were determined in ischemic and non-ischemic cortices. Axonal damage was determined using the pNF-H ELISA assay. Treatment with PRE-084 afforded neuroprotection following embolic stroke as evidenced by significantly reduced infarct volume and improved behavioural outcome. Remarkably, treatment with PRE-084 reduced levels of pro-inflammatory cytokines and enhanced anti-inflammatory cytokines. Levels of pNF-H were lower in rats treated with PRE-084 suggesting reduced axonal damage but this finding did not reach statistical significance. The findings of the present study suggest that part of the neuroprotective effects of sigma-1 receptor agonists may be mediated through a dual effect on cytokine release following stroke.

Mildronate treatment improves functional recovery following middle cerebral artery occlusion in rats

Mildronate (3-(2,2,2-trimethylhydrazinium) propionate) is an inhibitor of l-carnitine biosynthesis and an anti-ischemic drug. In the present study, we investigated the effects of mildronate in rats following focal cerebral ischemia. Male Wistar rats were subjected to transient occlusion of the middle cerebral artery (MCAO) for 90min, followed by the intraperitoneal administration of mildronate at doses of 100 and 200mg/kg 2h after reperfusion and then daily for an additional 14days. The beam-walking, rota-rod and cylinder tests were used to assess sensorimotor function, and vibrissae-evoked forelimb-placing and limb-placing tests examined responses to tactile and proprioceptive stimulation. Following behavioural testing, the infarct volume was measured. The cerebellar concentrations of l-carnitine, γ-butyrobetaine (GBB) and mildronate were also measured. The results showed that saline-treated MCAO rats had minor or no spontaneous recovery in sensorimotor and proprioceptive function up to 14days post-stroke. Treatment with mildronate at a dose of 200mg/kg was found to accelerate recovery of motor and proprioceptive deficits in limb-placing, cylinder and beam-walking tests. Analysis of rat cerebellar tissue extracts revealed that l-carnitine and GBB concentrations changed with mildronate treatment; the concentration of l-carnitine was significantly decreased by mildronate treatment, whereas the concentration of GBB was significantly increased. Cerebellar concentrations of mildronate also increased in a dose-dependent manner following systemic administration. Infarct size did not differ among the experimental groups on post-stroke day 14. The present study suggests that mildronate treatment improves the functional outcome in MCAO rats without influencing infarct size.

[Early ischemic preconditioning against focal transient and permanent brain ischemia in rats: role of collateral circulation]

We hypothesize that early ischemic preconditioning (IPC) can afford protection against focal brief and prolonged cerebral ischemia with subsequent reperfusion as well as permanent brain ischemia in rats by amelioration of regional cerebral blood flow. Adult male Wistar rats (n=97) were subjected to transient (30 and 60 minutes) and permanent middle cerebral artery (MCA) occlusion. IPC protocol consisted of two episodes of 5-min common carotid artery occlusion + 5-min reperfusion prior to test ischemia either followed by 48 hours of reperfusion or not. Triphenyltetrazolium chloride and Evans blue were used for delineation of infarct size and anatomical area at risk (comprises ischemic penumbra and ischemic core), respectively. Blood flow in the MCA vascular bed was measured with use of Doppler ultrasound. The IPC resulted in significant infarct size limitation in both transient and permanent MCA occlusion. Importantly, IPC caused significant reduction of area at risk after 30 min of focal ischemia as compared to controls [med(min-max) 11.4% (3.59-2 0.35%) vs. 2.47% (0.8-9.31%), p = 0.018] but it failed to influence area at risk after 5 min of ischemia [med(min-max) 7.61% (6.32-10.87%) vs. 8.2% (4.87-9.65%), p > 0.05]. No differences in blood flow were found between IPC and control groups using Doppler ultrasound. This is suggestive of the fact that IPC does not really influence blood flow in the large cerebral arteries such as MCA but it might have some effect on smaller arteries. It seems that, along with well established cytoprotective effects of IPC, IPC-mediated reduction of area at risk by means of improvement in local cerebral blood flow may contribute to infarct size limitation after focal transient and permanent brain ischemia in rats.

[Neuroprotective effects of lipoic acid and superoxide dismutase in the rat model of cerebral ischemia]

BACKGROUND

the present study was aimed at investigation of neuroprotective effects of alpha-lipoic acid (LA) and superoxide dismutase (SOD) in brain ischemia in rats.

METHODS

two models were used to produce brain ischemia: focal ischemia (permanent left middle cerebral artery occlusion) and permanent ligation of both CCA without subsequent reperfusion. Cu/Zn-SOD at a dose 5 mg/kg, i.v. and LA at a dose of 20 mg/kg, i.p. were injected 30 minutes prior or 5 minutes after onset of ischemia. The end-points of the study were histochemically determined: infarction size, ultrastructural changes in the cerebral tissue, and survival rate.

RESULTS

LA administration 30 minutes prior to ischemia dramatically reduced infarction size (p < 0.001). Injection of LA 5 minutes after beginning of ischemia did not affect the infarction size. Besides, infarction ion size was unchanged after injection of SOD 30 minutes prior to ischemia.

CONCLUSION

the LA treatment regimen used in this study resulted in significant cerebral protection against ischemia. In contrast, SOD did not show any protective effects in focal and forebrain ischemia.

Preventive effect of silymarin in cerebral ischemia-reperfusion-induced brain injury in rats possibly through impairing NF-κB and STAT-1 activation

Silymarin and silibinin are bioactive components isolated from Silybum marianum. They have been reported to exhibit anti-oxidative and anti-inflammatory effects. Many studies revealed that drugs with potent anti-inflammatory potential can protect animals against inflammation-associated neurodegenerative disease, e.g., stroke. In this current work we established an animal model of acute ischemic stroke injury by inducing cerebral ischemic/reperfusion (CI/R) in rats to elucidate whether silymarin or silibinin can protect animals from CI/R injury. Pretreatment with silymarin, but not silibinin, dose-dependently (1-10μg/kg, i.v.) reduced CI/R-induced brain infarction by 16-40% and improved neurological deficits in rats with a stroke. Elevated pathophysiological biomarkers for CI/R-induced brain injury, including lipid peroxidation, protein nitrosylation, and oxidative stress, were all reduced by silymarin. In addition, expression of inflammation-associated proteins (e.g., inducible nitric oxide synthase, cyclooxygenase-2 and myeloperoxidase), and transcriptional factors (e.g., nuclear factor (NF)-kappa B and signal transducer and activator of transcription (STAT)-1), as well as production of proinflammatory cytokine (e.g., interleukin-1β and tumor necrosis factor-α) was all significantly prevented by silymarin. Furthermore, an in vitro study on microglial BV2 cells showed that silymarin could inhibit nitric oxide and superoxide anion production, possibly by interfering with NF-κB nuclear translocation/activation. Likewise, silymarin pretreatment also inhibited IκB-α degradation and NF-κB nuclear translocation in brain tissues of ischemic rats. Our results reveal that silymarin, but not its active component silibinin, protected rats against CI/R-induced stroke injury by amelioration of the oxidative and nitrosative stresses and inflammation-mediated tissue injury through impeding the activation of proinflammatory transcription factors (e.g., NF-κB and STAT-1) in the upregulation of proinflammatory proteins and cytokines in stroke-damaged sites. In conclusion, silymarin displays beneficial effects of preventing inflammation-related neurodegenerative disease, e.g., stroke, which needs further investigation and clinical evidences.

Ginkgo biloba leaf extract (EGb761) combined with neuroprotective agents reduces the infarct volumes of gerbil ischemic brain

Ginkgo biloba exerts many pharmacological actions. It possesses antioxidant properties, the ability of neurotransmitter/receptor modulation and antiplatelet activation factor. This research is designed to investigate the neuroprotective effects of long-term treatment with EGb761 (a standard form of the extract of Ginkgo biloba leaf) in combination with MgSO(4), FK506, or MK-801 on the infarct volume of male gerbils' brain induced by unilateral middle cerebral artery occlusion (MCAO). Thirty-five gerbils fed a standard diet were intragastrically given water or EGb761 (100 mg/kg/day) for one week. Five randomized groups were established: control (n = 7), EGb761 (n = 8), EGb761 + MgSO(4) (n = 7), EGb761 + FK506 (n = 7), and EGb761 + MK-801 (n = 6). The three drug-combination groups were injected with MgSO(4) (90 mg/kg), FK506 (0.5 mg/kg), or MK-801 (1 mg/kg), respectively 30 min before MCAO. Gerbils were anesthetized and craniectomized to expose the right middle cerebral artery (MCA). The right MCA was constricted with an 8-0 suture to produce a permanent ligation for 24 hours. Postmortem infarct volumes were determined by quantitative image analysis of 2,3,5-triphenyltetrazolium chloride (TTC)-stained brain sections. Results showed that the total infarct volumes of the four treated groups either EGb761 alone or in combination with drugs were lower than the control group by 36.1% (EGb761 alone), 40.3% (EGb761 + MgSO(4)), 35.3% (EGb761 + FK506), and 56.4% (EGb761 + MK-801), respectively (p < 0.01). The main affected areas of the brain in the four treated groups were significantly focused between 4 and 6 mm from the frontal pole, when compared to the control group (p < 0.01). All animals in the five groups had infarctions in both cortex and subcortex. These results indicate that long-term pre-treatment of EGb761 administered either alone or in combination with drugs significantly effective neuroprotection on infarct volume in gerbil ischemic brains.

Neuroprotective effect of memantine combined with topiramate in hypoxic-ischemic brain injury

Glutamate receptor-mediated neurotoxicity is a major mechanism contributing to hypoxic-ischemic brain injury (HIBI). Memantine is a safe non-competitive NMDA receptor blocker characterized by its low affinity and fast unblocking kinetics. Topiramate is an AMPA/KA receptor blocker and use-dependent sodium channel blocker with several other neuroprotective actions and little neurotoxicity. We hypothesized that the coadministration of memantine and topiramate would be highly effective to attenuate HIBI in neonatal rats. Seven-day-old Sprague-Dawley rat pups were subjected to right common carotid artery ligation and hypoxia for 2 h, and then were randomly and blindly assigned to one of four groups: vehicle, memantine, topiramate and combination group. Brain injury was evaluated by gross damage and weight deficit of the right hemisphere at 22d after hypoxic-ischemia (HI) and by neurofunctional assessment (foot-fault test) at 21d post-HI. Acute neuronal injury was also evaluated by microscopic damage grading at 72 h post-HI. Results showed the combination of memantine and topiramate improved both pathological outcome and performance significantly. The drug-induced apoptotic neurodegeneration was assessed by TUNEL staining at 48 h post-HI and the result showed no elevated apoptosis in all observed areas. The result of the experiment indicates the combination therapy is safe and highly effective to reduce brain damage after HIBI.

Apotransferrin, C1‐esterase inhibitor, and alpha 1‐acid glycoprotein for cerebral protection during experimental hypothermic circulatory arrest

BACKGROUND

Because of current limitations in improving metabolic support to the brain during hypothermic circulatory arrest (HCA), attenuation of ischemia-reperfusion injury remains an area of therapeutic intervention of relevance. Apotransferrin (Apo-Tf), alpha 1-acid glycoprotein (AGP), and C1-esterase inhibitor (C1-INH) have been herein evaluated as potential beneficial agents in reducing the ischemia-reperfusion injury in a surviving model of HCA.

METHODS

Apo-Tf 100 mg/kg (n = 6), C1-INH 50 IU/kg (n = 6), AGP 100 mg/kg (n = 6), or NaCl 0.9% 2 ml/kg (n = 6) were randomly administered to 24 juvenile pigs after a 75-min period HCA at a brain temperature of 18 degrees C.

RESULTS

Animals in the Apo-Tf group had a slightly better 7-day survival (66.7%) compared with the other study groups (50%), but such a difference was not statistically significant. Some favorable changes in the brain glucose metabolism parameters were observed in the AGP, C1-INH, and Apo-Tf groups, but these did not reach statistical significance. Semiquantitative analysis of the histopathological findings did not show any significant difference between the study groups. However, only two out of four surviving animals in the Apo-Tf group developed brain infarction, whereas all three survivors of the remaining study groups developed brain infarction.

CONCLUSIONS

Although the small size of the study groups may affect the present findings, none of the metabolic and hemodynamic parameters as well as outcome endpoints indicate a substantial therapeutic efficacy of Apo-Tf, AGP, and C1-INH as neuroprotective agents after experimental HCA.

Prevention of Glutamate Accumulation and Upregulation of Phospho-Akt may Account for Neuroprotection Afforded by Bergamot Essential Oil against Brain Injury Induced by Focal Cerebral Ischemia in Rat

The effects of bergamot essential oil (BEO; Citrus bergamia, Risso) on brain damage caused by permanent focal cerebral ischemia in rat were investigated. Administration of BEO (0.1-0.5 ml/kg but not 1 ml/kg, given intraperitoneally 1 h before occlusion of the middle cerebral artery, MCAo) significantly reduced infarct size after 24 h permanent MCAo. The most effective dose (0.5 ml/kg) resulted in a significant reduction of infarct extension throughout the brain, especially in the medial striatum and the motor cortex as revealed by TTC staining of tissue slices. Microdialysis experiments show that BEO (0.5 ml/kg) did not affect basal amino acid levels, whereas it significantly reduced excitatory amino acid, namely aspartate and glutamate, efflux in the frontoparietal cortex typically observed following MCAo. Western blotting experiments demonstrated that these early effects were associated, 24 h after permanent MCAo, to a significant increase in the phosphorylation and activity of the prosurvival kinase, Akt. Indeed, BEO significantly enhanced the phosphorylation of the deleterious downstream kinase, GSK-3beta, whose activity is negatively regulated via phosphorylation by Akt.

Delayed postconditioning protects against focal ischemic brain injury in rats

Background

We and others have reported that rapid ischemic postconditioning, interrupting early reperfusion after stroke, reduces infarction in rats. However, its extremely short therapeutic time windows, from a few seconds to minutes after reperfusion, may hinder its clinical translation. Thus, in this study we explored if delayed postconditioning, which is conducted a few hours after reperfusion, offers protection against stroke.

Methods and Results

Focal ischemia was generated by 30 min occlusion of bilateral common carotid artery (CCA) combined with permanent occlusion of middle cerebral artery (MCA); delayed postconditioning was performed by repetitive, brief occlusion and release of the bilateral CCAs, or of the ipsilateral CCA alone. As a result, delayed postconditioning performed at 3h and 6h after stroke robustly reduced infarct size, with the strongest protection achieved by delayed postconditioning with 6 cycles of 15 min occlusion/15 min release of the ipsilateral CCA executed from 6h. We found that this delayed postconditioning provided long-term protection for up to two months by reducing infarction and improving outcomes of the behavioral tests; it also attenuated reduction in 2-[¹⁸F]-fluoro-2-deoxy-D-glucose (FDG)-uptake therefore improving metabolism, and reduced edema and blood brain barrier leakage. Reperfusion in ischemic stroke patients is usually achieved by tissue plasminogen activator (tPA) application, however, t-PA's side effect may worsen ischemic injury. Thus, we tested whether delayed postconditioning counteracts the exacerbating effect of t-PA. The results showed that delayed postconditioning mitigated the worsening effect of t-PA on infarction.

Conclusion

Delayed postconditioning reduced ischemic injury after focal ischemia, which opens a new research avenue for stroke therapy and its underlying protective mechanisms.

Neuroprotective effects of berberine on stroke models in vitro and in vivo

Berberine is an alkaloid derived from herb medicine Coptidis Rhizom. Although there are increasing evidences that berberine exhibits neuroprotective effects against ischemic brain damage, little is known about the mechanism. In this study, we investigated the effect of berberine on ischemic injury in a middle cerebral artery occlusion (MCAO) model. We found that berberine improved neurological outcome and reduced ischemia/reperfusion (I/R)-induced cerebral infarction 48h after MCAO. The protective effect of berberine was confirmed in in vitro study. Berberine protected PC12 cells against oxygen-glucose deprivation (OGD)-induced injury. The results showed that berberine inhibited reactive oxygen species (ROS) generation, and subsequent release of pro-apoptotic factor cytochrome c and apoptosis-inducing factors (AIFs) evoked by OGD. Findings of this study suggest that berberine protects against ischemic brain injury by decreasing the intracellular ROS level and subsequently inhibiting mitochondrial apoptotic pathway.

Intra-arterial nimodipine to treat symptomatic cerebral vasospasm following traumatic subarachnoid haemorrhage. Technical case report

Intra-arterial Nimodipine administration can be an effective alternative to papaverine or balloon angioplasty for the treatment of cerebral vasospasm refractory to medical therapy. It has been used for intractable vasospasm due to aneurysmal subarachnoid haemorrhage (SAH) with convincing results and no significant complications in small case series. This report describes of a patient with symptomatic and angiographically documented vasospasm following traumatic SAH which was refractory to maximal medical therapy and successfully treated with intra-arterial infusion of Nimodipine. This first reported technical note is with special reference to the nimodipine administration modalities, clinical and neuroradiological criteria of selection as well as the follow up of the patient.

Dynamic changes in cortical NADH fluorescence in rat focal ischemia: evaluation of the effects of hypothermia on propagation of peri-infarct depolarization by temporal and spatial analysis

Suppression of peri-infarct depolarizations (PIDs) is one of the major mechanisms of hypothermic protection against transient focal cerebral ischemia. Previous studies have shown the lack of hypothermic protection against permanent focal ischemia. We hypothesized the lack of hypothermic protection was due to the poor efficacy in suppression of PIDs. To examine the hypothesis, we elucidated the effects of hypothermia on the manner of propagation of PIDs with temporal and spatial resolutions using NADH (reduced nicotinamide adenine dinucleotide) fluorescence images by illuminating the parietal-temporal cortex with ultraviolet light. Spontaneously hypertensive rats (n=14) were subjected to permanent focal ischemia by occlusion of the middle cerebral and left common carotid arteries. 2-h hypothermia (30 degrees C) was initiated before ischemia. Although hypothermia delayed the appearance of PIDs, it did not suppress their appearance. Furthermore, 54% of the PIDs enlarged the high-intensity area of NADH fluorescence in the hypothermia group, similar to the normothermia group (53%). The high-intensity area of NADH fluorescence widened by each PID was larger in the hypothermia group than in the normothermia group. These findings suggest that PIDs even in hypothermia are one of the major factors causing growth of infarction, emphasizing the importance of therapy that targets suppression of PIDs even during hypothermia.

Estrogen inhibits Fas-mediated apoptosis in experimental stroke

Estrogen is protective in experimental cerebral ischemia, yet the mechanism remains unclear. Fas-mediated apoptosis has been shown to be induced after cerebral ischemia and significantly contribute to ischemic brain damage. In this study, we tested if estrogen is protective against cerebral ischemia by suppressing Fas-mediated apoptosis. 17Beta-estradiol-treated and untreated ovariectomized (OVX) female mice were subjected to 2 h middle cerebral artery occlusion (MCAO). Expression of Fas and Fas-associated death domain (FADD) were measured at 3, 6 and 12 h of reperfusion by RT-PCR and Western blot, respectively. Post-ischemic activities of caspase-8 and -3 activities, the two downstream effectors of Fas-induced apoptosis, were also assayed at same time points by ELISA. Finally, Fas antibody-induced cell death in primary cortical neurons was assayed by fluorescence activated cell sorter (FACS) in the presence and absence of estradiol. Our data showed that estradiol-treated OVX female mice sustained smaller infarct compared to untreated OVX mice. Ischemia upregulated Fas and FADD expression, and increased caspase-8 and -3 activities in OVX female mouse cortex, which were significantly attenuated by estradiol. Estradiol also significantly inhibited Fas antibody-induced neuronal cell apoptosis. Our data suggests that inhibition of ischemia-induced Fas-mediated apoptosis is an important mechanism of neuroprotection by estrogen in cerebral ischemia.

Optimization of a therapeutic protocol for intravenous injection of human mesenchymal stem cells after cerebral ischemia in adult rats

The systemic injection of human mesenchymal stem cells (hMSCs) prepared from adult bone marrow has therapeutic benefits after cerebral artery occlusion in rats, and may have multiple therapeutic effects at various sites and times within the lesion as the cells respond to a particular pathological microenvironment. However, the comparative therapeutic benefits of multiple injections of hMSCs at different time points after cerebral artery occlusion in rats remain unclear. In this study, we induced middle cerebral artery occlusion (MCAO) in rats using intra-luminal vascular occlusion, and infused hMSCs intravenously at a single 6 h time point (low and high cell doses) and various multiple time points after MCAO. From MRI analyses lesion volume was reduced in all hMSC cell injection groups as compared to serum alone injections. However, the greatest therapeutic benefit was achieved following a single high cell dose injection at 6 h post-MCAO, rather than multiple lower cell infusions over multiple time points. Three-dimensional analysis of capillary vessels in the lesion indicated that the capillary volume was equally increased in all of the cell-injected groups. Thus, differences in functional outcome in the hMSC transplantation subgroups are not likely the result of differences in angiogenesis, but rather from differences in neuroprotective effects.

Effects of microplasmin on recovery in a rat embolic stroke model

OBJECTIVES

The purpose of the present study was to examine the effects of microplasmin on behavioral performance and infarct volume after middle cerebral artery occlusion (MCAO) in rats. Some experiments support that microplasmin may have neuroprotective and thrombolytic properties.

METHODS

Eighty rats underwent surgery and were embolized in the right carotid territory with a fibrin-rich embolus and randomly assigned into three groups: 5 mg/kg microplasmin, 10 mg/kg microplasmin or saline (control). Groups treated with microplasmin received 50% bolus injection 10 minutes after embolization and 50% continuous infusion during the following hour. Animals from all groups were trained to obtain high baseline scores in Montoya's staircase test before embolization and were retested during 7-14 days after surgery.

RESULTS

When pre-maturely dead animals were excluded, no differences were observed among groups regarding infarct volumes. Furthermore, mortality was significantly lower in Group 1 than in Group 2 (p<0.05) and when performances were evaluated 7-14 days after surgery, Group 1 was significantly better than Group 2 concerning fine motor performance (p<0.05) and also achieved more normal bodyweight (p<0.05).

DISCUSSION

Among surviving animals, 5 mg/kg microplasmin treatment had no effect compared to saline-treated control animals; 5 mg/kg microplasmin reduced mortality and improved both behavioral rehabilitation and bodyweight compared to 10 mg/kg microplasmin treatment, while saline-treated animals did not differ from animals treated with 10 mg/kg microplasmin. Overall, these results indicate a potential beneficial effect of 5 mg/kg microplasmin treatment, while 10 mg/kg may worsen outcomes.