Measured Infarct Volume Research Articles

Effect of focal mild hypothermia on expression of MMP-9, TIMP-1, Tau-1 and β-APP in rats with cerebral ischaemia/reperfusion injury

Primary objective: Following stroke, hypothermia is reported to reduce both cellular and extracellular damage. This study aimed to examine the effects of focal mild hypothermia on proteins associated with both extracellular (matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of MMP-9 (TIMP-1)) and cellular damage (Tau-1 and β-amyloid precursor protein (β-APP)) to characterize the protective effects of hypothermia.Methods and procedures: Male Wistar rats received ischaemic damage using a transient, focal ischaemia/reperfusion model. Afterwards, one group (HT) received 6 hours of focal mild hypothermia (33 °C) applied to the head, while another remained at normal temperature (NT). The brains were collected at 6, 12, 24, 48 and 72 hours after hypothermia to measure infarct volume ratio and to detect cells immunopositive for MMP-9, TIMP-1, Tau-1 and β-APP, while neurological deficits were examined separately after 2 weeks.Main outcomes and results: Focal mild hypothermia had no effect on infarct volume ratio but expression of MMP-9, TIMP-1 Tau-1 and β-APP was decreased. Furthermore, neurological function in the HT group was better than in the NT group.Conclusions: Focal mild hypothermia has protective effects on cerebral ischaemia-reperfusion injury characterized by decreased expression of MMP-9, TIMP-1, Tau-1 and β-APP, along with improvement of neurological function despite no changes in infarct volume.

The Utility of Infarct Volume Measurement in Pediatric Ischemic Stroke

This study aims to determine if stroke volume as measured on diffusion-weighted imaging is associated with neurologic outcome in children with acute arterial ischemic stroke. A cohort of patients presenting to a tertiary care children's hospital with acute ischemic stroke were studied. The relationship between stroke volume, clinical characteristics, and neurologic outcome utilizing the Glasgow Outcome Scale were analyzed. In children with poor outcome, the median volume of infarction on diffusion-weighted imaging was larger when compared with children who had a good outcome. Children with stroke volume >10% of total brain volume were more likely than patients with stroke volume <5% total brain volume to have a poor outcome. Seizures were associated with a 10.5-fold increase in the risk of a poor outcome. Stroke volume, in conjunction with clinical characteristics, can assist practitioners in identifying a subset of patients with acute ischemic stroke who might benefit from aggressive medical and/or surgical management.

Automated Cerebral Infarct Volume Measurement in Follow-up Noncontrast CT Scans of Patients with Acute Ischemic Stroke

Cerebral infarct volume as observed in follow-up CT is an important radiologic outcome measure of the effectiveness of treatment of patients with acute ischemic stroke. However, manual measurement of CIV is time-consuming and operator-dependent. The purpose of this study was to develop and evaluate a robust automated measurement of the CIV. The CIV in early follow-up CT images of 34 consecutive patients with acute ischemic stroke was segmented with an automated intensity-based region-growing algorithm, which includes partial volume effect correction near the skull, midline determination, and ventricle and hemorrhage exclusion. Two observers manually delineated the CIV. Interobserver variability of the manual assessments and the accuracy of the automated method were evaluated by using the Pearson correlation, Bland-Altman analysis, and Dice coefficients. The accuracy was defined as the correlation with the manual assessment as a reference standard. The Pearson correlation for the automated method compared with the reference standard was similar to the manual correlation (R = 0.98). The accuracy of the automated method was excellent with a mean difference of 0.5 mL with limits of agreement of -38.0-39.1 mL, which were more consistent than the interobserver variability of the 2 observers (-40.9-44.1 mL). However, the Dice coefficients were higher for the manual delineation. The automated method showed a strong correlation and accuracy with the manual reference measurement. This approach has the potential to become the standard in assessing the infarct volume as a secondary outcome measure for evaluating the effectiveness of treatment.

Increased Neurogenesis Contributes to the Promoted Behavioral Recovery by Constraint‐Induced Movement Therapy after Stroke in Adult Rats

Increased Neurogenesis Contributes to the Promoted Behavioral Recovery by Constraint‐Induced Movement Therapy after Stroke in Adult Rats

Neuroprotection conferred by post‐ischemia ethanol therapy in experimental stroke: an inhibitory effect on hyperglycolysis and NADPH oxidase activation

Ethanol provides neuroprotection following ischemia/reperfusion. This study assessed ethanol's effect on hyperglycolysis and NADPH oxidase (NOX) activation. Adult, male Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) for 2 h. Three sets of experiments were conducted to determine ethanol's effect on (i) conferring neuroprotection by measuring infarct volume and neurological deficits 24 h post reperfusion; (ii) cerebral glucose metabolism and lactic acidosis by measuring brain and blood glucose concentrations and protein expression of glucose transporter 1 and 3 (GLUT1, GLUT3), phosphofructokinase (PFK), as well as lactic acidosis by measuring lactate dehydrogenase (LDH), and lactate; and (iii) nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activation by detecting enzymatic activity and subunit expression at 3 h after reperfusion. When administered upon reperfusion, ethanol (1.5 g/kg) reduced infarct volume by 40% (p < 0.01) and neurological deficits by 48% at 24 h post reperfusion while reducing (p < 0.01) elevations in glycolytic protein expression and lactate levels during early reperfusion (3 h). Ethanol increased the reductions in cerebral glucose concentration at 3 h post reperfusion by 64% (p < 0.01) while enhancing (p < 0.01) post stroke blood glucose concentration, suggesting a reduced cellular glucose uptake and utilization. Ethanol decreased (p < 0.01) stroke-induced NOX activation by reducing enzymatic activity and gp91(phox) expression by 45% and 38%, respectively. Post-ischemia ethanol treatment exerts neuroprotection through attenuation of hyperglycolysis and associated NOX activation. Because of the lack of associated hypoglycemia and selectivity toward decreasing cerebral metabolism, further investigation of ethanol's use as a post-stroke therapy, especially in the context of hyperglycemia, seems warranted.

Abstract WP103: Endothelial Nitric Oxide Synthase Regulates White Matter Changes after Stroke

Background: Stroke induced white matter damage is associated with neurological functional deficits, but the underlying mechanisms are not well understood. Endothelial nitric oxide synthase knockout (eNOS-/-) mice exhibited a higher mortality, more severe neurological functional deficit, and decreased neurogenesis, angiogenesis and arteriogenesis after stroke than wild type mice. There are no reports as to whether eNOS is related to the white matter change post-stroke. Methods: Adult male C57BL/6 WT and eNOS -/- mice were subjected to permanent middle cerebral artery occlusion (MCAo) by a filament and sacrificed 7 days after MCAo. Functional evaluation, infarct volume measurement, and immunostaining for analysis of white matter changes were performed. Results: There is no significant difference in the infarction volume between wild type and eNOS -/- (wild type : 23.09%±3.32%; eNOS-/-: 27.83%±4.92%, p=0.436, n=9/group). However, eNOS -/- mice showed significantly decreased functional outcome tested by the singal pellet reaching test (wild type: 38.46%%±1.43%, eNOS-/-: 27.45%±2.41%, p=0.0017). eNOS -/- mice also exhibited increased white matter damage compared to wild type mice, including decrease: 1. Axonal density stained by Bielshowsky Silver in the ipsilateral striatal bundles (wild type: 22.06%±3.0%, eNOS-/-: 13.32%±2.18%,, p=0.031), and in the contralateral striatal bundles (wild type: 65.35%±3.97%, eNOS-/-: 29.38%±5.84%, p=0.02); 2. Density of phasphorylated neurofilament by SMI31-immunoflureoscent staining (wild type: 24.11%±2.06%, eNOS-/-: 7.90%±1.70%, p=0.009); 3. The number of CNPase-positive oligodendrocytes in the ischemic border (wild type: 52.23±5.10, eNOS-/-: 35.59±5.33, p=0.041); 4. The number of NG2-positive oligodendrocyte progenitors in the ischemic border (wild type: 26.22±2.31, eNOS-/-: 18.38±1.95, p=0.0187). There is no significant difference in the density of Luxol fast blue stained myelin in the ipsilateral striatal bundles between wild type and eNOS -/- mice (wild type: 25.21%±3.64%; eNOS-/-: 21.39%±6.29%, p=0.260). Conclusions: We are the first to report that eNOS not only regulates vascular changes and neurogenesis, but also plays an important role in white matter changes after stroke.

Abstract WMP1: DWI ASPECT Scores And Infarct Volume As Predictors Of Outcome After Recanalization In Middle Cerebral Artery Stroke

Background and Purpose: Final infarct volume has previously been shown to be a major predictor of outcome after endovascular therapy for middle cerebral artery (MCA) occlusion. However, the importance of specific location of infarct within the MCA territory has not been described. We sought to assess the predictive value of specific topographic regions as predictors of outcomes in a homogeneous cohort of patients treated with endovascular therapy of M1 occlusive disease who underwent post procedure MRI. Methods: A retrospective review of our prospectively maintained single center endovascular database was performed. Automated software was used to measure infarct volume and the DWI ASPECT score was assessed by visual inspection using standard templates. Univariate and multivariate analysis was performed to determine predictors of favorable outcomes using each of the 10 regions as part of the ASPECT score as well as total ASPECT score. Results: 100 patients were identified. 56% were female. Median age was 70. Successful recanalization was achieved with TIMI 2/3 flow in 87% of patients and TICI 2B/3 in 61% of patients. Good outcomes (mRS 0-2 at 3 months) in 46% of patients. There was no difference between outcomes based on the hemisphere involved. Median final infarct on DWI MRI at 24 hours was 39 cc. Median ASPECT score was 6. In multivariate analysis, strong predictors of good outcomes included: age (OR 0.88, 95% CI 0.8-0.96, p=0.006), serum glucose on admission (OR 0.98, 95% CI 0.97-1, p=0.046) and ASPECT score on MRI (OR 0.7, 95% CI 0.03-1.05, p=0.03). There was a high correlation between the volume of infarct and ASPECT score on the post recanalization MRI (Spearman’s rho of -0.76). Conclusions: Quantitative (automated software) and semi-quantitative (ASPECT score values) measurements of infarct size are highly predictive of outcomes after recanalization therapy in middle cerebral artery infarcts. No single topographic region or combination of regions is predictive of outcome, whereas total ASPECT scores are highly predictive. These data support the role of post procedural MRI in guiding prognosis after anterior circulation infarct.

Abstract TMP1: Infarct Location And Volumes As Predictors Of Outcome After Endovascular Recanalization Of Basilar Artery Occlusion

Background and Purpose: Prognostic information after endovascular recanalization of basilar artery occlusion is important for guiding aggressiveness of subsequent care. While final infarct volumes have been shown to correlate with outcomes in anterior circulation strokes, no such relationship has been described in basilar artery occlusions. We sought to determine the relationship between the volume of final infarction, location of infarction and outcome of clinical course in patients treated with endovascular therapy for basilar artery occlusion at our institution. Methods: A retrospective review of our prospectively maintained endovascular stroke database identified 103 patients of which 59 patients underwent post treatment MRI. Automated software was used to measure infarct volume. Results: Patients included in the study had the following features: mean age 61, mean NIHSS 20, female 24%. Successful recanalization (TIMI 2/3) occurred in 53/59 patients (90%). Infarcts were divided into topographic regions (see Table). Good outcomes (mRS 0-2 at 3 months) were achieved in 32% of patients. 71% of patients with no brainstem infarct had a good outcome (p=0.03). 46% of patients with no thalamic infarct had a good outcome (p=0.049). In multivariate analysis, independent predictors of good outcomes were brainstem infarct volume (OR 0.25, 95% CI 0.11-0.61, p=0.002) and age (OR 0.84, CI 0.74-.91, p=0.0018). Patients with good outcomes had a mean brainstem infarct volume of 1.45 cc, while patients with poor outcomes had a mean brainstem infarct volume of 6 cc (p=0.002). Conclusions: Rate of good outcomes after recanalization of basilar artery occlusion is 32%. Presence and volume of brainstem infarct, presence of thalamic infarct and patient age are the strongest predictors of outcome. Further studies will address whether these parameters can be used prospectively in prognosticating outcomes after basilar artery occlusive disease.

Automated infarction core delineation using cerebral and perfused blood volume maps

Thrombolytic therapy in patients with acute ischemic stroke is contraindicated when the infarction core exceeds a given threshold. To date, there are no standardized guidelines for computed tomography infarction core assessment. Current practice involves use of thresholding methods, where the results are further adjusted by an experienced physician. An automated method for infarction core delineation and volume measurement was developed and tested. CT postprocessing software was developed for analysis of whole brain perfused blood volume (PBV) and cerebral blood volume (CBV) maps. The program was designed for potential use with mean transit time (MTT) or cerebral blood flow (CBF) maps. The proposed method was tested on a set of 12 patients on both PBV and CBV maps with whole brain coverage by comparison with the results of a simple thresholding method and with manually marked findings provided by two independent physicians. The proposed method produced a marked infarct core volume corresponding to 53% of the manually delineated volumes. The simple thresholding method with the optimal threshold, using the same dataset, marked 15[Formula: see text] larger volume compared to the volume delineated by physicians. An automated infarction core segmentation method based on local neighborhood features was developed and tested, demonstrating its utility in distinguishing between infarcted and non-infarcted areas, as well as reduction in the number of false positives and volume error.

Neuroprotective effects of bacopaside I in ischemic brain injury

Bacopa monnieri (L.) WETTST. is extensively used in traditional Indian medicine as a nerve tonic. The neuropharmacological properties of bacopaside I, an important component from B. monnieri, have not been studied so far. The present study investigated the effects and possible mechanisms of bacopaside I in a rat model of transient focal ischemia induced by middle cerebral artery occlusion (MCAO). Adult male Sprague-Dawley rats were divided into five groups: sham-operated group, ischemia group, and three bacopaside I-treated groups (3, 10 and 30 mg/kg) respectively. Bacopaside I or vehicle (0.5% CMC-Na) was administered orally once a day for 6 days. On the third day, the rats were subjected to 2 h right MCAO via the intraluminal filament technique and 70 h reperfusion. Assessment of behavioral deficits both at 22 and 70 h, and measurement of cerebral infarct volume, edema, cerebral energy metabolism, relative enzyme activities, malondialdehyde (MDA) content, nitric oxide (NO) level, and antioxidant enzyme activities at 70 h, performed after MCAO reperfusion. Bacopaside I (10 and 30 mg/kg) treatment produced significant reduction in neurological deficits at 22 and 70 h, and significantly reduced cerebral infarct volume and edema at 70 h, when compared with the ischemia group. Animal, that were orally treated with bacopaside I (3, 10 and 30 mg/kg) showed increased the brain ATP content, energy charge (EC), total adenine nucleotides (TAN), nitric oxide (NO) level, Na+K+ATPase and Ca2+Mg2+ATPase activity. Bacopaside I (3, 10 and 30 mg/kg) treatment also improved antioxidant enzyme activities including brain superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), in varying degrees, compared with the ischemia group. In addition, three doses of bacopaside I (3, 10 and 30 mg/kg) markedly inhibited the increase in MDA content of the brain. These findings indicated that bacopaside I possess a neuroprotective effect against injury caused by cerebral ischemia. The protective mechanism might be related to improving cerebral energy metabolism and increasing antioxidant levels.

Neuroprotective effects of chloroform and petroleum ether extracts of Nigella sativa seeds in stroke model of rat

PURPOSE:Stroke still remains a challenge for the researchers and scientists for developing ideal drug. Several new drugs are being evaluated showing excellent results in preclinical studies but when tested in clinical trials, they failed. Many herbal drugs in different indigenous system of medicine claim to have beneficial effects but not extensively evaluated for stroke (cerebral ischemia).AIM:The present study was undertaken to evaluate chloroform and petroleum ether extract of Nigella sativa seeds administered at a dose of 400 mg/kg, per orally for seven days in middle cerebral artery occluded (MCAO) rats for its neuroprotective role in cerebral ischemia.MATERIALS AND METHODS:Focal cerebral ischemia was induced by middle cerebral artery occlusion for two hours followed by reperfusion for 22 hours. After 24 hours, grip strength, locomotor activity tests were performed in different treatment groups of rats. After completing behavioral tests, animals were sacrificed; brains were removed for the measurement of infarct volume followed by the estimation of markers of oxidative stress.RESULTS:Both chloroform and petroleum ether extracts-pretreated rats showed improvement in locomotor activity and grip strength, reduced infarct volume when compared with MCAO rats. MCA occlusion resulted in the elevation of levels of thiobarbituric acid reactive substance (TBARS), while a reduction in the levels of glutathione (GSH) and antioxidant enzymes viz. superoxide dismutase (SOD) and catalase levels were observed. Pre-treatment of both extracts of Nigella sativa showed reduction in TBARS, elevation in glutathione, SOD, and catalase levels when compared with MCAO rats.CONCLUSION:The chloroform and petroleum ether extract of Nigella sativa showed the protective effects in cerebral ischemia. The present study confirms the antioxidant, free radical scavenging, and anti-inflammatory properties of Nigella sativa already reported.

Thromboembolic stroke in C57BL/6 mice monitored by 9.4 T MRI using a 1H cryo probe

BackgroundA new thromboembolic animal model showed beneficial effects of t-PA with an infarct volume reduction of 36.8% in swiss mice. Because knock-out animal experiments for stroke frequently used C57BL76 mice we evaluated t-PA effects in this mouse strain and measured infarct volume and vascular recanalisation in-vivo by using high-field 9.4 T MRI and a 1H surface cryo coil.MethodsClot formation was triggered by microinjection of murine thrombin into the right middle cerebral artery (MCA). Animals (n = 28) were treated with 10 mg/kg, 5 mg/kg or no tissue plasminogen activator (t-PA) 40 min after MCA occlusion. For MR-imaging a Bruker 9.4 T animal system with a 1H surface cryo probe was used and a T2-weighted RARE sequence, a diffusion weighted multishot EPI sequence and a 3D flow-compensated gradient echo TOF angiography were performed.ResultsThe infarct volume in animals treated with t-PA was significantly reduced (0.67 ± 1.38 mm3 for 10 mg/kg and 10.9 ± 8.79 mm3 for 5 mg/kg vs. 19.76 ± 2.72 mm3 ; p < 0.001) compared to untreated mice. An additional group was reperfused with t-PA inside the MRI. Already ten minutes after beginning of t-PA treatment, reperfusion flow was re-established in the right MCA. However, signal intensity was lower than in the contralateral MCA. This reduction in cerebral blood flow was attenuated during the first 60 minutes after reperfusion. 24 h after MCA occlusion and reperfusion, no difference in signal intensity of the contralateral and ipsilateral MCAs was observed.ConclusionsWe confirm a t-Pa effect using this stroke model in the C57BL76 mouse strain and demonstrate a chronological sequence MRI imaging after t-PA using a 1H surface cryo coil in a 9.4 T MRI. This setting will allow testing of new thrombolytic strategies for stroke treatment in-vivo in C57BL76 knock-out mice.

Prediction of Subacute Infarct Size in Acute Middle Cerebral Artery Stroke: Comparison of Perfusion-weighted Imaging and Apparent Diffusion Coefficient Maps

To compare perfusion-weighted (PW) imaging and apparent diffusion coefficient (ADC) maps in prediction of infarct size and growth in patients with acute middle cerebral artery infarct. This study was approved by the local institutional review board. Written informed consent was obtained from all 80 patients. Subsequent infarct volume and growth on follow-up magnetic resonance (MR) images obtained within 6 days were compared with the predictions based on PW images by using a time-to-peak threshold greater than 4 seconds and ADC maps obtained less than 12 hours after middle cerebral artery infarct. ADC- and PW imaging-predicted infarct growth areas and infarct volumes were correlated with subsequent infarct growth and follow-up diffusion-weighted (DW) imaging volumes. The impact of MR imaging time delay on the correlation coefficient between the predicted and subsequent infarct volumes and individual predictions of infarct growth by using receiver operating characteristic curves were assessed. The infarct volume measurements were highly reproducible (concordance correlation coefficient [CCC] of 0.965 and 95% confidence interval [CI]: 0.949, 0.976 for acute DW imaging; CCC of 0.995 and 95% CI: 0.993, 0.997 for subacute DW imaging). The subsequent infarct volume correlated (P<.0001) with ADC- (ρ=0.853) and PW imaging- (ρ=0.669) predicted volumes. The correlation was higher for ADC-predicted volume than for PW imaging-predicted volume (P<.005), but not when the analysis was restricted to patients without recanalization (P=.07). The infarct growth correlated (P<.0001) with PW imaging-DW imaging mismatch (ρ=0.470) and ADC-DW imaging mismatch (ρ=0.438), without significant differences between both methods (P=.71). The correlations were similar among time delays with ADC-predicted volumes but decreased with PW imaging-based volumes beyond the therapeutic window. Accuracies of ADC- and PW imaging-based predictions of infarct growth in an individual prediction were similar (area under the receiver operating characteristic curve [AUC] of 0.698 and 95% CI: 0.585, 0.796 vs AUC of 0.749 and 95% CI: 0.640, 0.839; P=.48). The ADC-based method was as accurate as the PW imaging-based method for evaluating infarct growth and size in the subacute phase.

Influence of exercise training on ischemic brain injury in type 1 diabetic rats

While exercise training (ExT) appears to influence cerebrovascular function during type 1 diabetes (T1D), it is not clear whether this beneficial effect extends to protecting the brain from ischemia-induced brain injury. Thus our goal was to examine whether modest ExT could influence transient focal ischemia-induced brain injury along with nitric oxide synthase (NOS)-dependent dilation of cerebral (pial) arterioles during T1D. Sprague-Dawley rats were divided into four groups: nondiabetic sedentary, nondiabetic ExT, diabetic (streptozotocin; 50 mg/kg ip) sedentary, and diabetic ExT. In the first series of studies, we measured infarct volume in all groups of rats following right MCA occlusion for 2 h, followed by 24 h of reperfusion. In a second series of studies, a craniotomy was performed over the parietal cortex, and we measured responses of pial arterioles to an endothelial NOS (eNOS)-dependent, a neuronal NOS (nNOS)-dependent, and a NOS-independent agonist in all groups of rats. We found that sedentary diabetic rats had significantly larger total, cortical, and subcortical infarct volumes following ischemia-reperfusion than sedentary nondiabetic, nondiabetic ExT, and diabetic ExT rats. Infarct volumes were similar in sedentary nondiabetic, ExT nondiabetic, and ExT diabetic rats. In contrast, ExT did not alter infarct size in nondiabetic compared with sedentary nondiabetic rats. In addition, ExT diabetic rats had impaired eNOS- and nNOS-dependent, but not NOS-independent, vasodilation that was restored by ExT. Thus ExT of T1D rats lessened ischemic brain injury following middle cerebral artery occlusion and restored impaired eNOS- and nNOS-dependent vascular function. Since the incidence of ischemic stroke is increased during T1D, we suggest that our finding are significant in that modest ExT may be a viable preventative therapeutic approach to lessen ischemia-induced brain injury that may occur in T1D subjects.

Chlorogenic acid ameliorates brain damage and edema by inhibiting matrix metalloproteinase-2 and 9 in a rat model of focal cerebral ischemia

Chlorogenic acid (CGA) has been reported to have various beneficial effects on the cardiovascular and central nervous systems. The purpose of the current study was to investigate whether CGA has protective effects against cerebral ischemia and whether these effects are due to modification of brain edema-related vascular factors. In a rat model of transient middle cerebral artery occlusion (MCAo, 2h of occlusion followed by 22h of reperfusion), we measured infarct volume and performed behavioral test to evaluate the effects of CGA on brain damage and sensory-motor functional deficits. Brain water content and Evans blue extravasation were measured to evaluate brain edema and blood brain barrier (BBB) damage. Lipid peroxidation (LPO) and the expressions and activities of matrix metalloproteinase (MMP)-2 and MMP-9 were measured to investigate the mechanisms of action. Intraperitoneal injection of CGA (3, 10, and 30mg/kg) at 0h and 2h after MCAo dose-dependently reduced infarct volume and sensory-motor functional deficits. It also reduced brain water content and Evans blue extravasation. Mechanistically, CGA reduced LPO and MMPs expressions and activities. These results suggest that CGA reduces brain damage, BBB damage and brain edema by radical scavenging activity and the inhibitory effects on MMP-2 and MMP-9.

Abstract 395: Formation of New Coronary Collaterals After Acute Myocardial Infarction in Mouse

Variation in extent of the native pre-existing collateral (COL) circulation, ie, COL number and average diameter in healthy tissues, is a major determinant of the variation in severity of tissue injury after acute obstruction. Indirect evidence suggests that coronary COL extent varies widely in presumed healthy humans. Although the cause of this variation is unknown, studies in non-heart tissues of healthy mouse strains have found that differences in genetic background are a major determinant. Whether this applies to the heart is unknown, because no model exists to investigate the coronary COL circulation in mice. In addition, little is known regarding whether new COLs can be induced to form in individuals with few native COLs. To address these questions, we developed a mouse model that combines high-resolution (capillary-level) microangiography and ligation (LADX) with measurement of coronary COL conductance index and infarct volume. Adult (3-mos-old) mouse strains chosen for their large rank-order difference in native COL extent in brain and hindlimb-BLKS &gt; C57BL/6 &gt; A &gt; BALB/c-all lack native coronary COLs. After LADX, all strains formed new COLs by day-3 that reached maximum number and diameter by day-14. However, rank-order for new COL formation differed from the above, ie, C57BL/6 @ BALB/c &gt; BLKS &gt; A; COL conductance and infarct volume -1 followed this same rank-order. Moreover, the rank-order for new COL formation differed from the rank-order for COL remodeling after arterial ligation in brain and hindlimb, ie, A &gt; C57BL/6 &gt; BALB/c. Ongoing studies to determine the mechanisms of new COL formation after LADX find strongly reduced COL formation and conductance and increased infarct volume in C57BL/6 mice deficient in monocyte chemoattractant protein-1 or its receptor (CCR2)-effects partially rescued by bone marrow transplantation. Conclusions: Unlike other tissues, the mouse heart lacks native COLs. Mice thus provide a model to study coronary collaterogenesis free of complications posed by remodeling of pre-existing COLs. Gene polymorphisms underlying variation in ischemic coronary collaterogenesis differ from those underlying variation in embryonic formation of native COLs. MCP-1 and bone marrow cells play an important role in new COL formation.

The Relationship between Acute Stress Hyperglycemia and Infarct Volume in Ischemic Stroke (P07.032)

Objective: To investigate the relationship between acute infarct volume on diffusion-weighted imaging (DWI) and acute stress hyperglycemia (ASH) in a prospectively collected dataset. Background The published evidence on the relationship between ischemic lesion volume and ASH is conflicting. While some studies report higher infarct volumes in patients with ASH, others refute this by claiming that small infarcts such as lacunar infarcts are also associated with ASH. Small sample size, failure to use a consistent definition for ASH, inability to account for differences in timing of infarct volume and glucose measurements, and differences in infarct size determination contribute to the controversy. We sought to investigate the relationship between acute infarct volume and ASH in a prospectively collected dataset within the context of the Heart-Brain Interactions Study (HBS). Design/Methods: HBS is an ongoing study aiming to identify the neuroanatomic correlates of stroke-related cardiac injury and acute stress response. We performed blood glucose measurement within 36 hours and DWI within 72 hours of symptom onset in consecutive patients enrolled to the HBS. ASH was defined as elevated blood glucose (>144 mg/dl) in the absence of elevated Hemoglobin A1c ( Results: We identified 98 consecutive patients with ASH and 217 controls out of 1240. The median infarct volume was higher in patients than controls (11 cc vs. 4 cc, p Conclusions: The study shows that infarct volume is an independent predictor of ASH. The probability of ASH increases by increasing infarct volume. Disclosure: Dr. Helenius has nothing to disclose. Dr. Avery has nothing to disclose. Dr. Polnar has nothing to disclose. Dr. Caceres has nothing to disclose. Dr. Siket has nothing to disclose. Dr. AY has nothing to disclose.

Regulator of calcineurin 1 (Rcan1) has a protective role in brain ischemia/reperfusion injury

BackgroundAn increase in intracellular calcium concentration [Ca2+]i is one of the first events to take place after brain ischemia. A key [Ca2+]i-regulated signaling molecule is the phosphatase calcineurin (CN), which plays important roles in the modulation of inflammatory cascades. Here, we have analyzed the role of endogenous regulator of CN 1 (Rcan1) in response to experimental ischemic stroke induced by middle cerebral artery occlusion.MethodsAnimals were subjected to focal cerebral ischemia with reperfusion. To assess the role of Rcan1 after stroke, we measured infarct volume after 48 h of reperfusion in Rcan1 knockout (KO) and wild-type (WT) mice. In vitro studies were performed in astrocyte-enriched cortical primary cultures subjected to 3% oxygen (hypoxia) and glucose deprivation (HGD). Adenoviral vectors were used to analyze the effect of overexpression of Rcan1-4 protein. Protein expression was examined by immunohistochemistry and immunoblotting and expression of mRNA by quantitative real-time Reverse-Transcription Polymerase Chain Reaction (real time qRT-PCR).ResultsBrain ischemia/reperfusion (I/R) injury in vivo increased mRNA and protein expression of the calcium-inducible Rcan1 isoform (Rcan1-4). I/R-inducible expression of Rcan1 protein occurred mainly in astroglial cells, and in an in vitro model of ischemia, HGD treatment of primary murine astrocyte cultures induced Rcan1-4 mRNA and protein expression. Exogenous Rcan1-4 overexpression inhibited production of the inflammatory marker cyclo-oxygenase 2. Mice lacking Rcan1 had higher expression of inflammation associated genes, resulting in larger infarct volumes.ConclusionsOur results support a protective role for Rcan1 during the inflammatory response to stroke, and underline the importance of the glial compartment in the inflammatory reaction that takes place after ischemia. Improved understanding of non-neuronal mechanisms in ischemic injury promises novel approaches to the treatment of acute ischemic stroke.

Using a novel in vivo model to study the function of nuclear factor kappa B in cerebral ischemic injury

SummaryBackgroundCerebral ischemia is a situation with a deficit blood supply to the brain, which eventually leads to cell death, inflammation, and tissue damage. Nuclear factor kappa B (NF-κB) plays an important role in inflammation and immune regulation. The aim of this study was to test the function of the activation of NF-κB in vivo in cerebral ischemic injury.Material/MethodsWe generated an animal model that used the method of occlusion of the middle cerebral artery (MCAO). The 60 traits were equally divided into 5 groups to investigate the role of NAC pretreatment: (1) sham-operation (control), (2) ischemia for 6 hours, (3) ischemia for 6 hours and NAC pretreatment, (4) ischemia for 24 hours, (5) ischemia for 24 hours and NAC pretreatment. The 36 rats were divided randomly into 3 groups: (A) recombinant adenovirus expressing wild-type κBα (AdIκBαM) group, (B) recombinant adenovirus expressing wild-type IκBα (AdIκBα) group, and (C) simple ischemia group. Triphenyltetrazolium chloride (TTC) was used to measure infarct volume. Detection of expression of NF-κB was by Immunohistochemistry analysis.ResultsThe infarct size of the 24-hours ischemia groups were bigger than those of 6-hours ischemia groups (P<0.01). The infarct size of using NAC pretreatment groups was obviously reduced compared with saline control groups (P<0.01).The percentage of cortical p65-positive cells of the group of (A) were significantly less than the groups of (B) and (C).ConclusionsOur data suggest that N-acetylcysteine (NAC) and Ad-IκBα-Mut can inhibit the activation of NF-κB in vivo, reduce the focal infarct size, and protect the brain tissue in ischemia.

Nebivolol regulates eNOS and iNOS expressions and alleviates oxidative stress in cerebral ischemia/reperfusion injury in rats

AimsOxidative stress-induced cell damage is reported to contribute to the pathogenesis of cerebral ischemia/reperfusion injury. This study investigated the neuroprotective effect of nebivolol against cerebral ischemia/reperfusion insult in rats. Main methodsThe model adopted was that of surgically-induced forebrain ischemia, performed by means of bilateral common carotid artery occlusion for 1h, followed by reperfusion for 24h. The effects of 5 and 10mg/kg nebivolol, treated for 7days prior to ischemia/reperfusion insult, were investigated by estimating endothelial and inducible nitric oxide synthases (eNOS and iNOS) protein expressions and assessing oxidative stress-related biochemical parameters in the rat forebrain. Also, infarct volume measurement and histopathological study of the forebrain were examined. Key findingsAdministration of nebivolol increased eNOS expression with simultaneous decrease in iNOS expression in a dose dependent manner. Moreover, nebivolol inhibited ischemia/reperfusion-induced depletion of reduced glutathione level and decreased the elevated total nitric oxide end production and malondialdehyde levels, superoxide dismutase and lactate dehydrogenase activities. A notable finding is that catalase activity was not changed in response to either ischemia/reperfusion insult or nebivolol treatment. However, the results confirmed that nebivolol significantly reduced infarct volume and alleviated ischemia/reperfusion-induced histopathological changes. SignificanceThe present study demonstrates the neuroprotective effect of nebivolol against cerebral ischemia/reperfusion insult. Neuroprotection observed with nebivolol may possibly be explained by regulating eNOS and iNOS expressions and by inhibition of oxidative stress-induced injury. Thus, nebivolol may be considered as a potential candidate for treatment in patients who are prone to stroke.