Hyperglycemia Worsens Outcome After rt-PA Primarily in the Large-Vessel Occlusive Stroke Subtype

Canagliflozin, an Inhibitor of the Na+-Coupled D-Glucose Cotransporter, SGLT2, Inhibits Astrocyte Swelling and Brain Swelling in Cerebral Ischemia

Brain swelling is a major cause of death and disability in ischemic stroke. Drugs of the gliflozin class, which target the Na+-coupled D-glucose cotransporter, SGLT2, are approved for type 2 diabetes mellitus (T2DM) and may be beneficial in other conditions, but data in cerebral ischemia are limited. We studied murine models of cerebral ischemia with middle cerebral artery occlusion/reperfusion (MCAo/R). Slc5a2/SGLT2 mRNA and protein were upregulated de novo in astrocytes. Live cell imaging of brain slices from mice following MCAo/R showed that astrocytes responded to modest increases in D-glucose by increasing intracellular Na+ and cell volume (cytotoxic edema), both of which were inhibited by the SGLT2 inhibitor, canagliflozin. The effect of canagliflozin was studied in three mouse models of stroke: non-diabetic and T2DM mice with a moderate ischemic insult (MCAo/R, 1/24 h) and non-diabetic mice with a severe ischemic insult (MCAo/R, 2/24 h). Canagliflozin reduced infarct volumes in models with moderate but not severe ischemic insults. However, canagliflozin significantly reduced hemispheric swelling and improved neurological function in all models tested. The ability of canagliflozin to reduce brain swelling regardless of an effect on infarct size has important translational implications, especially in large ischemic strokes.

Effect of Admission Hyperglycemia on Safety and Efficacy of Intravenous Alteplase Before Thrombectomy in Ischemic Stroke: Post-hoc Analysis of the DIRECT-MT trial

Hyperglycemia is associated with decreased recanalization probability and increased risk of hemorrhagic complications for stroke patients treated with intravenous alteplase. However, whether hyperglycemia modifies alteplase treatment effect on clinical outcome in patients with large vessel occlusion stroke undergoing endovascular thrombectomy is uncertain. We conducted this study to determine a possible interaction effect between admission hyperglycemia and intravenous alteplase prior to thrombectomy in patients with large vessel occlusion stroke. In this post-hoc analysis of a randomized trial (DIRECT-MT) comparing intravenous alteplase before endovascular treatment vs. endovascular treatment only, 649 with available baseline glucose measurements were included. The treatment-by-admission hyperglycemia (defined as plasma glucose levels ≥ 7.8 mmol/L [140 mg/dL]) interaction was assessed using logistic regression models. As a result, among 649 patients included, 224 (34.5%) were hyperglycemic at admission. There was evidence of alteplase treatment effect modification by hyperglycemia (Pinteraction = 0.025). In patients without hyperglycemia, combination therapy was associated with better outcomes compared to mechanical thrombectomy alone (adjusted common odd ratio [acOR] 1.46, 95% CI [1.04-2.07]), but not in hyperglycemic patients (acOR 0.74, 95% CI [0.46-1.20]). Combination therapy led to an absolute increase of 6% excellent outcome (mRS 0-1) in non-hyperglycemic patients (aOR 1.71, 95% CI [1.05-2.79]), but resulted in a 12.3% absolute decrease (aOR 0.42 [95% CI, 0.19-0.95] in hyperglycemic patients (Pinteraction = 0.003). In conclusion, for large vessel occlusion patients directly presenting to a thrombectomy-capable hospital, hyperglycemia modified combination treatment effect on clinical outcome. Combination therapy was beneficial in patients without hyperglycemia, while thrombectomy alone may be preferred in hyperglycemic patients. Further studies are needed to confirm this result.Trial Registration Information: clinicaltrials.gov Identifier: NCT03469206.

Persistent hyperglycemia is a useful glycemic pattern to predict stroke mortality: a systematic review and meta-analysis

BACKGROUND

Glycemic patterns have been reported to be prognostic factors for stroke; however, this remains to be further evaluated. This meta-analysis aimed to evaluate the usefulness of glycemic patterns such as persistent hyperglycemia (PH) including short duration and long duration PH (SPH; LPH), admission hyperglycemia (AH), short-duration hyperglycemia (SH), and persistent normoglycemia (PN) in predicting stroke prognosis using published results.

METHODS

Major scientific databases including but are not limited to PubMed, EMBASE, Web of Science, Ovid, CNKI (Chinese National Knowledge Infrastructure), and Clinicaltrials.gov were searched till 1st March 2021 for clinical trials on the correlation between glycemic patterns and stroke outcomes. The primary outcome was defined as short-term (1- or 3-month) post-stroke mortality, and the secondary outcome was post-stroke hemorrhage at 6 months.

RESULTS

Ten studies involving 3584 individuals were included in the final analysis. In subgroup analyses, PH patients with no history of diabetes had increased post-stroke mortality (odds ratio [OR]: 4.80, 95% CI: 3.06-7.54) than patients with no PH; and patients with glucose levels > 140 mg/dl had greater mortality (OR: 5.12, 95% CI: 3.21-8.18) than those with glucose levels < 140 mg/dl; compared with AH patients, PH patients had increased short-term mortality (OR: 0.31, 95% CI: 0.16-0.60). In the prediction of stroke mortality among patients without diabetes, SPH (OR: 0.28, 95%CI: 0.12-0.69) seemed to be more related to increased mortality than LPH (OR: 0.35, 95% CI: 0.14--0.90).

CONCLUSIONS

PH, especially SPH, could predict increased post-stroke mortality in non-diabetic patients. The rank of individual glycemic patterns in predicting stroke mortality in non-diabetic patients was SPH > LPH > AH > PN.

Outcomes of Ischemic Stroke and Associated Factors Among Elderly Patients With Large-Artery Atherosclerosis: A Hospital-Based Follow-Up Study in China

Large-artery atherosclerotic (LAA) stroke is the most common subtype of ischemic stroke. However, risk factors for long-term outcomes of LAA stroke in the elderly Chinese population have not been well-described. Therefore, we aimed to assess outcomes and risk factors at 3, 12, and 36 months after LAA stroke onset among stroke patients aged 60 years and older. All consecutive LAA patients aged ≥ 60 years were prospectively recruited from Dongying People's Hospital between January 2016 and December 2018. The clinical features and outcome data at 3, 12, and 36 months after stroke were collected. Differences in outcomes and relationship between outcomes and risk factors were assessed. A total of 1,772 patients were included in our study (61.7% male, 38.3% female). The rates of mortality, recurrence, and dependency were 6.6, 12.6, and 12.6%, respectively, at 3 months after stroke onset. The corresponding rate rose rapidly at 36 months (23.2, 78.7, and 79.7%, respectively). We found the positive predictors associated outcomes at 3, 12, and 36 months after stroke onset. The relative risk (RR) with 95% confidential interval (CI) is 1.06 (1.02–1.10, P = 0.006) at 3 months, 1.06 (1.02–1.10, P = 0.003) at12 months, and 1.10 (1.05–1.15, P < 0.001) at 36 months after stroke onset for age; 1.09 (1.01–1.19, P = 0.029) at 12 months for fasting plasma glucose (FPG) level; 4.25 (2.14–8.43, P < 0.001) at 3 months, 4.95 (2.70–9.10, P < 0.001) at 12 months, and 4.82 (2.25–10.32, P < 0.001) at 36 months for moderate stroke; 7.56 (3.42–16.72, P < 0.001) at 3 months, 11.08 (5.26–23.34, P < 0.001) at 12 months, and 14.30 (4.85–42.11, P < 0.001) at 36 months for severe stroke, compared to mild stroke. Hypersensitive C-reactive protein (hs-CRP) level was an independent risk factor for mortality at different follow-up times, with the RR (95%) of 1.02 (1.01–1.02, P < 0.001) at 3 months, 1.01 (1.00–1.02, P = 0.002) at 12 months. White blood cell count (WBC) level was associated with both stroke recurrence (RR = 1.09, 95%CI: 1.01–1.18, P = 0.023) and dependency (RR = 1.10, 95%CI: 1.02–1.19, P = 0.018) at 3 months. In contrast, a higher level of low-density lipoprotein cholesterol (LDL-C) within the normal range was a protective factor for recurrence and dependency at shorter follow-up times, with the RR (95%) of 0.67 (0.51–0.89, P = 0.005) and 0.67 (0.50–0.88, P = 0.005), respectively. These findings suggest that it is necessary to control the risk factors of LAA to reduce the burden of LAA stroke. Especially, this study provides a new challenge to explore the possibility of lowering LDL-C level for improved stroke prognosis.

The Effect of Locally Administered Fibrinolytic Drugs Following Aneurysmal Subarachnoid Hemorrhage : A Meta-Analysis with Eight Randomized Controlled Studies

Objective

Rapid dissolution of blood clots reduces vasospasm and hydrocephalus after subarachnoid hemorrhage (SAH), and locally administered fibrinolytic drugs (LAFDs) could facilitate the dissolution. However, the efficacy of LAFDs remains controversial. The aim of this meta-analysis was to determine the efficacy of LAFDs for vasospasm and hydrocephalus and in clinical outcomes.

Methods

From PubMed, EMBASE, and Cochrane database, data were extracted by two authors. Meta-analysis was performed using a random effect model. Inclusion criteria were patients who had LAFDs with urokinase-type or recombinant tissue-plasminogen activator after SAH in comparison with medically untreated patients with fibrinolytic drugs. We only included randomized controlled trials (RCTs) in this analysis. The outcomes of interest were vasospasm, hydrocephalus, mortality, and 90-day unfavorable functional outcome.

Results

Data from eight RCTs with 550 patients were included. Pooled-analysis revealed that the LAFDs were significantly associated with lower rates of vasospasm (LAFDs group vs. control group, 26.5% vs. 39.2%; odds ratio [OR], 0.48; 95% confidence interval [CI], 0.32–0.73); hydrocephalus (LAFDs group vs. control group, 26.0% vs. 31.6%; OR, 0.54; 95% CI, 0.32–0.91); and mortality (LAFDs group vs. control group, 10.5% vs. 15.7%; OR, 0.58; 95% CI, 0.34–0.99). The proportion of 90-day unfavorable outcomes was lower in the LAFDs group (LAFDs group vs. control group, 32.7% vs. 43.5%; OR, 0.55; 95% CI, 0.37–0.80).

Conclusion

This meta-analysis with eight RCTs indicated that LAFDs were significantly associated with lower rates of vasospasm and hydrocephalus after SAH. Thus, LAFDs could consequently reduce mortality and improve clinical outcome after SAH.

Argatroban Increased the Basal Vein Drainage and Improved Outcomes in Acute Paraventricular Ischemic Stroke Patients

Background

Since venous drainage in acute arterial ischemic stroke has not been thoroughly researched, we evaluate the effect of argatroban, a selective direct thrombin inhibitor, as a therapy to increase the rate of basal vein Rosenthal (BVR) drainage and improve patients’ post-stroke outcomes.

Material/Methods

In this multicenter clinical trial, 60 eligible patients at 4.5 to 48 hours after the stroke onset were recruited. After being randomly allocated into 2 groups, they were treated with standard therapy either alone or with argatroban.

Results

Compared to the contralateral brain hemisphere, the mean flow velocity (MFV) in BVR drainage was significantly reduced in the stroke-afflicted ipsilateral hemisphere. After treatment with argatroban for 7 days, the MFV from BVR of the ipsilateral hemisphere in the argatroban treated group was significantly increased when compared to the control group. At 90 days after the onset of stroke, the MFV of BVR in the ipsilateral hemisphere was similar in both groups. Compared with controls, the argatroban-treated patients had smaller lesions from baseline to 7 days. Argatroban also improved National Institutes of Health Stroke Scale (NIHSS) scores on day 7 after the onset of stroke. Furthermore, the argatroban group’s neurological functions were superior to those of their untreated counterparts after 90 days. No difference was found in the incidence of adverse reactions between the 2 groups.

Conclusions

These observations indicate that vein drainage change may contribute to the acute phase of brain edema and the outcomes of ischemic stroke patients.

Clinical Trial Registration

URL-http://www.chictr.org

Unique identifier: ChiCTR-IPR-16008663

Telemedicine in Prehospital Acute Stroke Care: An Expanding Infrastructure for Treatment and Research

See Article by Geisler et al.

Elevated blood glucose is associated with aggravated brain edema in acute stroke

BACKGROUND AND PURPOSE

Clinical outcome after endovascular thrombectomy in patients with acute ischemic stroke still varies significantly. Higher blood glucose levels (BGL) have been associated with worse clinical outcome, but the pathophysiological causes are not yet understood. We hypothesized that higher levels of BGL are associated with more pronounced ischemic brain edema and worse clinical outcome mediated by cerebral collateral circulation.

METHODS

178 acute ischemic stroke patients who underwent mechanical thrombectomy were included. Early ischemic brain edema was determined using quantitative lesion water uptake on initial computed tomography (CT) and collateral status was assessed with an established 5-point scoring system in CT-angiography. Good clinical outcome was defined as functional independence (modified Rankin Scale [mRS] score 0-2). Multivariable logistic regression analysis was performed to predict functional independence and linear regression analyses to investigate the impact of BGL and collateral status on water uptake.

RESULTS

The mean BGL at admission was significantly lower in patients with good outcome at 90 days (116.5 versus 138.5 mg/dl; p < 0.001) and early water uptake was lower (6.3% versus 9.6%; p < 0.001). The likelihood for good outcome declined with increasing BGL (odds ratio [OR] per 100 mg/dl BGL increase: 0.15; 95% CI 0.02-0.86; p = 0.039). Worse collaterals (1% water uptake per point, 95% CI 0.4-1.7%) and higher BGL (0.6% per 10 mg/dl BGL, 95% CI 0.3-0.8%) were significantly associated with increased water uptake.

CONCLUSION

Elevated admission BGL were associated with increased early brain edema and poor clinical outcome mediated by collateral status. Patients with higher BGL might be targeted by adjuvant anti-edematous treatment.

Prevalence of diabetes and its effects on stroke outcomes: A meta-analysis and literature review

AIMS/INTRODUCTION

Diabetes mellitus is an established risk factor for stroke and maybe associated with poorer outcomes after stroke. The aims of the present literature review were to determine: (i) the prevalence of diabetes in acute stroke patients through a meta-analysis; (ii) the association between diabetes and outcomes after ischemic and hemorrhagic stroke; and (iii) to review the value of glycated hemoglobin and admission glucose-based tests in predicting stroke outcomes.

MATERIALS AND METHODS

Ovid MEDLINE and EMBASE searches were carried out to find studies relating to diabetes and inpatient stroke populations published between January 2004 and April 2017. A meta-analysis of the prevalence of diabetes from included studies was undertaken. A narrative review on the associations of diabetes and different diagnostic methods on stroke outcomes was carried out.

RESULTS

A total of 66 eligible articles met inclusion criteria. A meta-analysis of 39 studies (n = 359,783) estimated the prevalence of diabetes to be 28% (95% confidence interval 26-31). The rate was higher in ischemic (33%, 95% confidence interval 28-38) compared with hemorrhagic stroke (26%, 95% confidence interval 19-33) inpatients. Most, but not all, studies found that acute hyperglycemia and diabetes were associated with poorer outcomes after ischemic or hemorrhagic strokes: including higher mortality, poorer neurological and functional outcomes, longer hospital stay, higher readmission rates, and stroke recurrence. Diagnostic methods for establishing diagnosis were heterogeneous between the reviewed studies.

CONCLUSIONS

Approximately one-third of all stroke patients have diabetes. Uniform methods to screen for diabetes after stroke are required to identify individuals with diabetes to design interventions aimed at reducing poor outcomes in this high-risk population.

Influence of Admission Blood Glucose in Predicting Outcome in Patients With Spontaneous Intracerebral Hematoma

Background and Aims: Hyperglycemia or elevated blood glucose levels have been associated with poor outcomes in patients with ischemic stroke yet control of hyperglycemia has not resulted in good outcomes. High admission blood glucose (ABG) values have been mitigated by other poor prognosticators like large hematoma volume, intraventricular extension (IVE) of hematoma and poor GCS. The aim of this study was to evaluate the effects of blood glucose levels at admission, on mortality and functional outcomes at discharge and 3 months follow up. Methods: This was a retrospective observational study conducted at a tertiary care. Patients with spontaneous SICH were enrolled from a prospective SICH register maintained at our hospital. Blood glucose values were recorded on admission. Patients with traumatic hematomas, vascular malformations, aneurysms, and coagulation abnormalities were excluded from our study. Results: A total of 510 patients were included in the study. We dichotomised our cohort into two groups, group A with ABG>160 mg/dl and group B with ABG<160 mg/dl. Mean blood glucose levels in these two groups were 220.73 mg/dl and 124.37 mg/dl respectively, with group A having twice the mortality. mRS at discharge and 3 months was better in Group B (p ≤ 0.001) as compared to Group A. Age, GCS, volume of hematoma, ABG, IVE and Hydrocephalus were significant predictors of mortality and poor outcome on univariate analysis with a p < 0.05. The relationship between ABG and mortality (P = 0.249, 95% CI 0.948-1.006) and outcome (P = 0.538, 95% CI 0.997-1.005) failed to reach statistical significance on multivariate logistic regression. Age, Volume of hematoma and GCS were stronger predictors of mortality and morbidity. Conclusion: Admission blood glucose levels was not an independent predictor of mortality in our study when adjusted with age, GCS, and hematoma volume. The effect of high ABG on SICH outcome is probably multifactorial and warrants further research.

Complement Component C3 Promotes Cerebral Ischemia/Reperfusion Injury Mediated by TLR2/NFκB Activation in Diabetic Mice

Complement component C3 (C3), a key factor in the complement system, is heavily involved in various inflammation-associated diseases. However, it remains obscure for its role in the pathogenesis of cerebral ischemia/reperfusion (I/R) injury in diabetes. A transient middle cerebral artery occlusion (tMCAO) model was used for cerebral I/R injury in streptozotocin-induced diabetic mice. Cerebral infarct volume and neurological function were measured at different times of reperfusion. Complement C3 was measured by ELISA and western blotting. It was observed that complement C3 expression was increased in cerebral I/R injury of diabetic mice, whereas complement C3 deficiency abrogated the activation and injury. Furthermore, activating complement C3 promotes TLR2/NFκB activation after I/R injury in diabetic mice, which is inhibited by of the silencing of TLR2. Taken together, our data demonstrate that complement C3 promotes cerebral I/R injury via the TLR2/NFκB pathway in diabetic mice, and regulating the complement C3/TLR2/NFκB pathway may be a novel target for therapeutic intervention in diabetic stroke.

Hematoma Expansion Following Intracerebral Hemorrhage: Mechanisms Targeting the Coagulation Cascade and Platelet Activation

Hematoma expansion (HE), defined as a greater than 33% increase in intracerebral hemorrhage (ICH) volume within the first 24 hours, results in significant neurological deficits, and enhancement of ICH-induced primary and secondary brain injury. An escalation in the use of oral anticoagulants has led to a surge in the incidences of oral anticoagulation-associated ICH (OAT-ICH), which has been associated with a greater risk for HE and worse functional outcomes following ICH. The oral anticoagulants in use include vitamin K antagonists, and direct thrombin and factor Xa inhibitors. Fibrinolytic agents are also frequently administered. These all act via differing mechanisms and thus have varying degrees of impact on HE and ICH outcome. Additionally, antiplatelet medications have also been increasingly prescribed, and result in increased bleeding risks and worse outcomes after ICH. Aspirin, thienopyridines, and GPIIb/IIIa receptor blockers are some of the most common agents in use clinically, and also have different effects on ICH and hemorrhage growth, based on their mechanisms of action. Recent studies have found that reduced platelet activity may be more effective in predicting ICH risk, hemorrhage expansion, and outcomes, than antiplatelet agents, and activating platelets may thus be a novel target for ICH therapy. This review explores how dysfunctions or alterations in the coagulation and platelet cascades can lead to, and/or exacerbate, hematoma expansion following intracerebral hemorrhage, and describe the mechanisms behind these effects and the drugs that induce them. We also discuss potential future therapy aimed at increasing platelet activity after ICH.

Efficacy of Novel Carbon Nanoparticle Antioxidant Therapy in a Severe Model of Reversible Middle Cerebral Artery Stroke in Acutely Hyperglycemic Rats

INTRODUCTION

While oxidative stress can be measured during transient cerebral ischemia, antioxidant therapies for ischemic stroke have been clinically unsuccessful. Many antioxidants are limited in their range and/or capacity for quenching radicals and can generate toxic intermediates overwhelming depleted endogenous protection. We developed a new antioxidant class, 40 nm × 2 nm carbon nanoparticles, hydrophilic carbon clusters, conjugated to poly(ethylene glycol) termed PEG-HCCs. These particles are high-capacity superoxide dismutase mimics, are effective against hydroxyl radical, and restore the balance between nitric oxide and superoxide in the vasculature. Here, we report the effects of PEG-HCCs administered during reperfusion after transient middle cerebral artery occlusion (tMCAO) by suture in the rat under hyperglycemic conditions. Hyperglycemia occurs in one-third of stroke patients and worsens clinical outcome. In animal models, this worsening occurs largely by accelerating elaboration of reactive oxygen species (ROS) during reperfusion.

METHODS

PEG-HCCs were studied for their protective ability against hydrogen peroxide in b.End3 brain endothelial cell line and E17 primary cortical neuron cultures. In vivo, hyperglycemia was induced by streptozotocin injection 2 days before tMCAO. 58 Male Sprague-Dawley rats were analyzed. They were injected IV with PBS or PEG-HCCs (4 mg/kg 2×) at the time of recanalization after either 90- or 120-min occlusion. Rats were survived for up to 3 days, and infarct volume characteristics and neurological functional outcome (modified Bederson Score) were assessed.

RESULTS

PEG-HCCs were protective against hydrogen peroxide in both culture models. In vivo improvement was found after PEG-HCCs with 90-min ischemia with reduction in infarct size (42%), hemisphere swelling (46%), hemorrhage score (53%), and improvement in Bederson score (70%) (p = 0.068-0.001). Early high mortality in the 2-h in the PBS control group precluded detailed analysis, but a trend was found in improvement in all factors, e.g., reduction in infarct volume (48%; p = 0.034) and a 56% improvement in Bederson score (p = 0.055) with PEG-HCCs.

CONCLUSION

This nano-antioxidant showed some improvement in several outcome measures in a severe model of tMCAO when administered at a clinically relevant time point. Long-term studies and additional models are required to assess potential for clinical use, especially for patients hyperglycemic at the time of their stroke, as these patients have the worst outcomes.

Admission Glucose and Effect of Intra-Arterial Treatment in Patients With Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Hyperglycemia on admission is common after ischemic stroke. It is associated with unfavorable outcome after treatment with intravenous thrombolysis and after intra-arterial treatment. Whether hyperglycemia influences the effect of reperfusion treatment is unknown. We assessed whether increased admission serum glucose modifies the effect of intra-arterial treatment in patients with acute ischemic stroke.

METHODS

We used data from the MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands). Hyperglycemia was defined as admission serum glucose >7.8 mmol/L. The primary outcome measure was the adjusted common odds ratio for a shift in the direction of a better outcome on the modified Rankin Scale at 90 days, estimated with ordinal logistic regression. Secondary outcome variable was symptomatic intracranial hemorrhage. We assessed treatment effect modification of hyperglycemia and admission serum glucose levels with multiplicative interaction factors and adjusted for prognostic variables.

RESULTS

Four hundred eighty-seven patients were included. Mean admission serum glucose was 7.2 mmol/L (SD, 2.2). Fifty-seven of 226 patients (25%) randomized to intra-arterial treatment were hyperglycemic compared with 61 of 261 patients (23%) in the control group. The interaction of either hyperglycemia or admission serum glucose levels and treatment effect on modified Rankin Scale scores was not significant (P=0.67 and P=0.87, respectively). The same applied for occurrence of symptomatic hemorrhage (P=0.39 for hyperglycemia, P=0.39 for admission serum glucose).

CONCLUSIONS

We found no evidence for effect modification of intra-arterial treatment by admission serum glucose in patients with acute ischemic stroke.

CLINICAL TRIAL REGISTRATION

URL: www.isrctn.com. Unique identifier: ISRCTN10888758.

A Post-stroke Therapeutic Regimen with Omega-3 Polyunsaturated Fatty Acids that Promotes White Matter Integrity and Beneficial Microglial Responses after Cerebral Ischemia

White matter injury induced by ischemic stroke elicits sensorimotor impairments, which can be further deteriorated by persistent proinflammatory responses. We previously reported that delayed and repeated treatments with omega-3 polyunsaturated fatty acids (n-3 PUFAs) improve spatial cognitive functions and hippocampal integrity after ischemic stroke. In the present study, we report a post-stroke n-3 PUFA therapeutic regimen that not only confers protection against neuronal loss in the gray matter but also promotes white matter integrity. Beginning 2 h after 60 min of middle cerebral artery occlusion (MCAO), mice were randomly assigned to receive intraperitoneal docosahexaenoic acid (DHA) injections (10 mg/kg, daily for 14 days), alone or in combination with dietary fish oil (FO) supplements starting 5 days after MCAO. Sensorimotor functions, gray and white matter injury, and microglial responses were examined up to 28 days after MCAO. Our results showed that DHA and FO combined treatment-facilitated long-term sensorimotor recovery and demonstrated greater beneficial effect than DHA injections alone. Mechanistically, n-3 PUFAs not only offered direct protection on white matter components, such as oligodendrocytes, but also potentiated microglial M2 polarization, which may be important for white matter repair. Notably, the improved white matter integrity and increased M2 microglia were strongly linked to the mitigation of sensorimotor deficits after stroke upon n-3 PUFA treatments. Together, our results suggest that post-stroke DHA injections in combination with FO dietary supplement benefit white matter restoration and microglial responses, thereby dictating long-term functional improvements.

Embracing Biological and Methodological Variance in a New Approach to Pre-Clinical Stroke Testing

High-profile failures in stroke clinical trials have discouraged clinical translation of neuroprotectants. While there are several plausible explanations for these failures, we believe that the fundamental problem is the way clinical and pre-clinical studies are designed and analyzed for heterogeneous disorders such as stroke due to innate biological and methodological variability that current methods cannot capture. Recent efforts to address pre-clinical rigor and design, while important, are unable to account for variability present even in genetically homogenous rodents. Indeed, efforts to minimize variability may lessen the clinical relevance of pre-clinical models. We propose a new approach that recognizes the important role of baseline stroke severity and other factors in influencing outcome. Analogous to clinical trials, we propose reporting baseline factors that influence outcome and then adapting for the pre-clinical setting a method developed for clinical trial analysis where the influence of baseline factors is mathematically modeled and the variance quantified. A new therapy's effectiveness is then evaluated relative to the pooled outcome variance at its own baseline conditions. In this way, an objective threshold for robustness can be established that must be overcome to suggest its effectiveness when expanded to broader populations outside of the controlled environment of the PI's laboratory. The method is model neutral and subsumes sources of variance as reflected in baseline factors such as initial stroke severity. We propose that this new approach deserves consideration for providing an objective method to select agents worthy of the commitment of time and resources in translation to clinical trials.

Admission hyperglycemia and outcome after intravenous thrombolysis: is there a difference among the stroke-subtypes?

BACKGROUND

The prognostic influence of hyperglycemia in acute stroke has been well established. While in cortical stroke there is a strong association between hyperglycemia and poor outcome, this relation is less clear in lacunar stroke. It has been suggested that this discrepancy is present among patients treated with intravenous tissue plasminogen activator (tPA), but confirmation is needed.

METHODS

In two prospectively collected cohorts of patient treated with intravenous tPA for acute ischemic stroke, we investigated the effect of hyperglycemia (serum glucose level >8 mmol/L) on functional outcome in lacunar and non-lacunar stroke. Poor functional outcome was defined as modified Rankin Scale score ≥ 3 at 3 months.

RESULTS

A total of 1012 patients was included of which 162 patients (16%) had lacunar stroke. The prevalence of hyperglycemia did not differ between stroke subtypes (22% vs 21%, p = 0.85). In multivariate analysis hyperglycemia was associated with poor functional outcome in non-lacunar stroke (OR 2.1, 95% CI 1.39-3.28, p = 0.001). In patients with lacunar stroke, we did not find an association (OR 1.8, 95% CI 0.62-4.08, p = 0.43).

CONCLUSION

This study confirms a difference in prognostic influence of hyperglycemia between non-lacunar and lacunar ischemic stroke.

The Predictive Value of Motor-Evoked Potentials and the Silent Period on Patient Outcome after Acute Cerebral Infarction

BACKGROUND

The predictive value of neurophysiologic assessment on patients' outcome after acute cerebral infarction is poorly understood. The aim of this study was to investigate the prognostic value of motor-evoked potentials (MEPs) and the silent period (SP) on clinical outcome.

METHODS

A total of 202 patients with acute cerebral infarction were prospectively recruited. MEP and SP were recorded from the abductor pollicis brevis of the affected side within 10 days after stroke onset. Patient outcome was measured as the dependency rate.

RESULTS

Cortical MEP was induced in 78 patients whereas it was absent in 82 patients. The initial NIHSS (National Institutes of Health Stroke Scale) score was significantly lower in patients with MEP than in those without MEP (P < .001). Regression analysis demonstrated that a left-sided lesion (OR = .391, 95% CI .178-.858, P = .019), NIHSS at admission (OR = .826, 95% CI .744-.917, P < .001), and presence of MEP (OR = 3.918, 95% CI 1.770-8.672, P < .001) were independent predictors of outcome 3 months after stroke. Among patients with MEP, only the contralateral cortical SP value was significantly shorter in the good outcome subgroup (t = 2.541, P = .013). Receiver operating characteristic curve analysis demonstrated that SP was able to predict patients at higher risk of unfavorable outcome 3 months after stroke onset (area under the curve .721, 95% CI .58-.86, P = .008).

CONCLUSIONS

These data suggested that MEP and SP were useful tools to predict patients' acute outcomes following cerebral infarction.

Development of an Infarct Volume Algorithm to Correct for Brain Swelling After Ischemic Stroke in Rats

The primary measure for experimental stroke studies, infarct volume, can be affected by brain swelling. The algorithm by Lin et al. was developed to correct for brain swelling, however, the correction is not adequate. This chapter presents a new infarct volume algorithm that more appropriately corrects for brain hemisphere volume changes (swelling and stunted growth). Fifty-one adult rats were sacrificed 24 h after middle cerebral artery occlusion (MCAO). Forty-four P10 rat pups were sacrificed 48 h after hypoxia-ischemia (HI). Infarct volumes for 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) stained brains were calculated using our algorithm and that of Lin and colleagues. For MCAO animals, the algorithm of Lin et al. computed smaller infarct volumes than those of our algorithm. For HI animals, Lin et al.'s algorithm's infarct volumes were greater than those of our algorithm. For sham animals, Lin et al.'s algorithm's computed infarct volumes were significantly different from those of our algorithm. Our algorithm produces a more robust estimation of infarct volume than Lin et al.'s algorithm because the effects of ipsilesional hemisphere volume changes are minimized. Herein, our algorithm yields an infarct volume that better corrects for brain swelling and stunted brain growth compared with the algorithm of Lin et al.

Acute Hyperglycemia Is Associated with Immediate Brain Swelling and Hemorrhagic Transformation After Middle Cerebral Artery Occlusion in Rats

Hemorrhagic transformation occurs in as many as 48 % of stroke patients and is a major contributor to post-insult morbidity and mortality. Experimental models of hemorrhagic transformation are utilized for understanding the mechanisms behind its development, as well as for investigating potential therapeutics for prevention and reduction of bleeding. Thoroughly studying animal models of hemorrhagic transformation is critically important for testing novel treatments. Thus far, no study has examined the progression of brain swelling and hemorrhagic transformation after transient middle cerebral artery occlusion (MCAO). Herein, we investigate the development of infarction, brain swelling, and hemorrhagic transformation following MCAO in hyperglycemic rats. Twenty-five Sprague-Dawley rats were subjected to either 1.5 h of MCAO or sham surgery 15 min after induction of hyperglycemia. Animals were sacrificed at 0.25, 1, 3, or 24 h after reperfusion for measurement of infarct volume, brain swelling, and hemoglobin volume. Within 15 min of reperfusion, the infarct volume was significantly larger than in sham animals and did not increase in size over the 24 h. However, both brain swelling and hemorrhagic transformation, which began immediately after reperfusion, increase over 24 h after reperfusion.

Acute Hyperglycemia Does Not Affect Brain Swelling or Infarction Volume After Middle Cerebral Artery Occlusion in Rats

Stroke disproportionally affects diabetic and hyperglycemic patients with increased incidence and is associated with higher morbidity and mortality due to brain swelling. In this study, the intraluminal suture middle cerebral artery occlusion (MCAO) model was used to examine the effects of blood glucose on brain swelling and infarct volume in acutely hyperglycemic rats and normo-glycemic controls. Fifty-four rats were distributed into normo-glycemic sham surgery, hyperglycemic sham surgery, normo-glycemic MCAO, and hyperglycemic MCAO. To induce hyperglycemia, 15 min before MCAO surgery, animals were injected with 50 % dextrose. Animals were subjected to 90 min of MCAO and sacrificed 24 h after reperfusion for hemispheric brain swelling and infarct volume calculations using standard equations. While normo-glycemic and hyperglycemic animals after MCAO presented with significantly higher brain swelling and larger infarcts than their respective controls, no statistical difference was observed for either brain swelling or infarct volume between normo-glycemic shams and hyperglycemic shams or normo-glycemic MCAO animals and hyperglycemic MCAO animals. The findings of this study suggest that blood glucose does not have any significant effect on hemispheric brain swelling or infarct volume after MCAO in rats.

Critical early thrombolytic and endovascular reperfusion therapy for acute ischemic stroke victims: a call for adjunct neuroprotection

Today, there is an enormous amount of excitement in the field of stroke victim care due to the recent success of MR. CLEAN, SWIFT PRIME, ESCAPE, EXTEND-IA, and REVASCAT endovascular trials. Successful intravenous (IV) recombinant tissue plasminogen activator (rt-PA) clinical trials [i.e., National Institute of Neurological Disorders and Stroke (NINDS) rt-PA trial, Third European Cooperative Acute Stroke Study (ECASSIII), and Third International Stroke study (IST-3)] also need to be emphasized. In the recent endovascular and thrombolytic trials, there is statistically significant improvement using both the National Institutes of Health Stroke Scale (NIHSS) and the modified Rankin Score (mRS) scale, but neither approach promotes complete recovery in patients enrolled within any particular NIHSS or mRS score tier. Absolute improvement (mRS 0-2 at 90 days) with endovascular therapy is 13.5-31 %, whereas thrombolytics alone also significantly improve patient functional independence, but to a lesser degree (NINDS rt-PA trial 13 %). This article has 3 main goals: (1) first to emphasize the utility and cost-effectiveness of rt-PA to treat stroke; (2) second to review the recent endovascular trials with respect to efficacy, safety, and cost-effectiveness as a stroke treatment; and (3) to further consider and evaluate strategies to develop novel neuroprotective drugs. A thesis will be put forth so that future stroke trials and therapy development can optimally promote recovery so that stroke victims can return to "normal" life.

An Outcome Model for Intravenous rt-PA in Acute Ischemic Stroke

Most early phase trials in stroke and brain trauma have failed in phase 3, including efforts to improve acute ischemic stroke outcomes beyond that achieved by intravenous recombinant tissue plasminogen activator (t-PA) (IVT). With the exception of more recent stent retriever trials, most subsequent phase 3 trials failed. We previously showed that baseline imbalances, non-linear relationships of these factors to outcome, and unrepresentative control populations invalidate traditional statistical analysis in early trials of heterogeneous diseases such as stroke. We developed an alternative approach using a pooled outcome model derived from control arms of randomized clinical trial (RCTs). This model then permits comparing treatment trials to an expected outcome of a pooled population. Here, we hypothesized we could develop such a model for IVT and tested it against outcomes without IVT. We surveyed literature for all trials involving one arm with IVT reporting baseline National Institute Stroke Scale (NIHSS), age, and outcome. A non-linear fit was performed including multi-dimensional statistical intervals (±95 %) permitting visual comparison of outcomes at their own baselines. We compared models derived from non-IVT control arms. Models from 24 IVT RCTs representing 3195 subjects were successfully generated for functional outcome, modified Rankin Scale (mRS) 0-2 (r(2) = 0. 83, p < 0.001), and mortality (r(2) = 0.54; p = 0.001). We confirmed better outcomes compared to no IVT and mixed use IVT models across the range of baseline factors. It was possible to generate an expected outcome model for IVT from existing literature. We confirmed benefit compared to placebo. This model should be useful to compare to new agents without the need for statistical manipulation.

Peripheral to central: Organ interactions in stroke pathophysiology

Stroke is associated with a high risk of disability and mortality, and with the exception of recombinant tissue-type plasminogen activator for acute stroke, most treatments have proven ineffective. Clinical translation of promising experimental therapeutics is limited by inadequate stroke models and a lack of understanding of the mechanisms underlying acute stroke and how they affect outcome. Bidirectional communication between the ischemic brain and peripheral immune system modulates stroke progression and tissue repair, while epidemiological studies have provided evidence of an association between organ dysfunction and stroke risk. This crosstalk can determine the fate of stroke patients and must be taken into consideration when investigating the pathophysiological mechanisms and therapeutic options for stroke. This review summarizes the current evidence for interactions between the brain and other organs in stroke pathophysiology in basic and clinic studies, and discusses the role of these interactions in the progression and outcome of stroke and how they can direct the development of more effective treatment strategies.