Targeting Neutrophil α9 Improves Functional Outcomes After Stroke in Mice With Obesity-Induced Hyperglycemia.

BACKGROUND: Obesity-induced hyperglycemia is a significant risk factor for stroke. Integrin α9ß1 is expressed on neutrophils and stabilizes adhesion to the endothelium via ligands, including Fn-EDA (fibronectin containing extra domain A) and tenascin C. Although myeloid deletion of α9 reduces susceptibility to ischemic stroke, it is unclear whether this is mediated by neutrophil-derived α9. We determined the role of neutrophil-specific α9 in stroke outcomes in a mice model with obesity-induced hyperglycemia. METHODS: α9Neu-KO (α9fl/flMRP8Cre+) and littermate control α9WT (α9fl/flMRP8Cre-) mice were fed on a 60% high-fat diet for 20 weeks to induce obesity-induced hyperglycemia. Functional outcomes were evaluated up to 28 days after stroke onset in mice of both sexes using a transient (30 minutes) middle cerebral artery ischemia. Infarct volume (magnetic resonance imaging) and postreperfusion thrombo-inflammation (thrombi, fibrin, neutrophil, phospho-nuclear factor kappa B [p-NFκB], TNF [tumor necrosis factor]-α, and IL [interleukin]-1ß levels, markers of neutrophil extracellular traps) were measured post 6 or 48 hours of reperfusion. In addition, functional outcomes (modified Neurological Severity Score, rota-rod, corner, and wire-hanging test) were measured for up to 4 weeks. RESULTS: Stroke upregulated neutrophil α9 expression more in obese mice (P<0.05 versus lean mice). Irrespective of sex, deletion of neutrophil α9 improved functional outcomes up to 4 weeks, concomitant with reduced infarct, improved cerebral blood flow, decreased postreperfusion thrombo-inflammation, and neutrophil extracellular traps formation (NETosis) (P<0.05 versus α9WT obese mice). Obese α9Neu-KO mice were less susceptible to thrombosis in FeCl3 injury-induced carotid thrombosis model. Mechanistically, we found that α9/cellular fibronectin axis contributes to NETosis via ERK (extracellular signal-regulated kinase) and PAD4 (peptidyl arginine deiminase 4), and neutrophil α9 worsens stroke outcomes via cellular fibronectin-EDA but not tenascin C. Obese wild-type mice infused with anti-integrin α9 exhibited improved functional outcomes up to 4 weeks (P<0.05 versus vehicle). CONCLUSIONS: Genetic ablation of neutrophil-specific α9 or pharmacological inhibition improves long-term functional outcomes after stroke in mice with obesity-induced hyperglycemia, most likely by limiting thrombo-inflammation.

The Stroke Preclinical Assessment Network: Rationale, Design, Feasibility, and Stage 1 Results.

Cerebral ischemia and reperfusion initiate cellular events in brain that lead to neurological disability. Investigating these cellular events provides ample targets for developing new treatments. Despite considerable work, no such therapy has translated into successful stroke treatment. Among other issues-such as incomplete mechanistic knowledge and faulty clinical trial design-a key contributor to prior translational failures may be insufficient scientific rigor during preclinical assessment: nonblinded outcome assessment; missing randomization; inappropriate sample sizes; and preclinical assessments in young male animals that ignore relevant biological variables, such as age, sex, and relevant comorbid diseases. Promising results are rarely replicated in multiple laboratories. We sought to address some of these issues with rigorous assessment of candidate treatments across 6 independent research laboratories. The Stroke Preclinical Assessment Network (SPAN) implements state-of-the-art experimental design to test the hypothesis that rigorous preclinical assessment can successfully reduce or eliminate common sources of bias in choosing treatments for evaluation in clinical studies. SPAN is a randomized, placebo-controlled, blinded, multilaboratory trial using a multi-arm multi-stage protocol to select one or more putative stroke treatments with an implied high likelihood of success in human clinical stroke trials. The first stage of SPAN implemented procedural standardization and experimental rigor. All participating research laboratories performed middle cerebral artery occlusion surgery adhering to a common protocol and rapidly enrolled 913 mice in the first of 4 planned stages with excellent protocol adherence, remarkable data completion and low rates of subject loss. SPAN stage 1 successfully implemented treatment masking, randomization, prerandomization inclusion/exclusion criteria, and blinded assessment to exclude bias. Our data suggest that a large, multilaboratory, preclinical assessment effort to reduce known sources of bias is feasible and practical. Subsequent SPAN stages will evaluate candidate treatments for potential success in future stroke clinical trials using aged animals and animals with comorbid conditions.

Effects of the Menstrual Cycle on Neurological Disorders.

PURPOSE OF REVIEW: The menstrual cycle involves recurrent fluctuations in hormone levels and temperature via neuroendocrine feedback loops. This paper reviews the impact of the menstrual cycle on several common neurological conditions, including migraine, seizures, multiple sclerosis, stroke, and Parkinson's disease. RECENT FINDINGS: The ovarian steroid hormones, estrogen and progesterone, have protean effects on central nervous system functioning that can impact the likelihood, severity, and presentation of many neurological diseases. Hormonal therapies have been explored as a potential treatment for many neurological diseases with varying degrees of evidence and success. Neurological conditions also impact women's reproductive health, and the cessation of ovarian function with menopause may also alter the course of neurological diseases. Medication selection must consider hormonal effects on metabolism and the potential for adverse drug reactions related to menstruation, fertility, and pregnancy outcomes. Novel medications with selective affinity for hormonal receptors are desirable. Neurologists and gynecologists must collaborate to provide optimal care for women with neurological disorders.

Neurologic complications of heart surgery.

Cardiac surgeries are commonly associated with neurologic complications. The type and complexity of the surgery, as well as patients' comorbidities, determine the risk for these complications. Awareness and swift recognition of these complications may have significant implications on management and prognosis. Recent trials resulted in an expansion of the time window to treat patients with acute ischemic stroke with intravenous thrombolysis and/or mechanical thrombectomy using advanced neuroimaging for screening. The expanded time window increases the reperfusion treatment options for patients that suffer a periprocedural ischemic stroke. Moreover, there is now limited data available to help guide management of intracerebral hemorrhage in patients undergoing treatment with anticoagulation for highly thrombogenic conditions, such as left ventricular assist devices and mechanical valves. In addition to cerebrovascular complications patients undergoing heart surgery are at increased risk for seizures, contrast toxicity, cognitive changes, psychological complications, and peripheral nerve injuries. We review the neurological complications associated with the most common cardiac surgeries and discuss clinical presentation, diagnosis and management strategies.

Management of Ischemic Stroke Following Left Ventricular Assist Device.

BACKGROUND: Acute ischemic stroke is a common complication and an important source of morbidity and mortality in patients with left ventricular assist devices. There are no standardized protocols to guide management of ischemic stroke among patients with left ventricular assist device. We evaluated our experience treating patients who had an acute ischemic stroke following left ventricular assist device placement. METHODS: We retrospectively reviewed all patients who underwent left ventricular assist device placement from 2010-2019 and identified patients who had acute ischemic stroke following left ventricular assist device placement. RESULTS: Of 216 patients having left ventricular assist device placement (mean±SD age 52.9±16.2 years, women 26.9%), 19 (8.8%) had acute ischemic stroke (mean±SD age 55.8±12.0 years, women 36.8%). Median (interquartile range) time to ischemic stroke following left ventricular assist device placement was 96 (29-461) days. At the time of the ischemic stroke, 16/19 (84.2%) patients were taking both antiplatelet and anticoagulation therapy, 1/19 (5.3%) patient was receiving only anticoagulants, 1/19 (5.3%) patient was taking aspirin and dipyridamole, and 1/19 (5.3%) patient was not taking antithrombic agents. INR was subtherapeutic (INR<2.0) in 7/17 (41.2%) patients. No patient was eligible to receive thrombolytic therapy, while 5/19 (26.3%) underwent mechanical thrombectomy. Anticoagulation was continued in the acute stroke phase in 11/19 (57.9%) patients and temporarily held in 8/19 (42.1%) patients. Hemorrhagic transformation of the ischemic stroke occurred in 6/19 (31.6%) patients. Anticoagulation therapy was continued following ischemic stroke in 4/6 (66.7%) patients with hemorrhagic transformation. CONCLUSIONS: While thrombolytic therapy is frequently contraindicated in the management of acute ischemic stroke following left ventricular assist device, mechanical thrombectomy remains a valid option in eligible patients. Anticoagulation is often continued through the acute phase of ischemic stroke secondary to concerns for LVAD thrombosis. The risks and benefits of continuing anticoagulation must be weighed carefully, especially in patients with large infarct volume, as hemorrhagic transformation remains a common complication.

Differential Risk Factors and Outcomes of Ischemic Stroke due to Cervical Artery Dissection in Young Adults.

INTRODUCTION: Cervical artery dissection (CeAD) is a major cause of ischemic stroke in young adults. Our understanding of the specific risk factors and clinical course of CeAD is still evolving. In this study, we evaluated the differential risk factors and outcomes of CeAD-related strokes among young adults. METHODS: The study population consisted of young patients 15-45 years of age consecutively admitted with acute ischemic stroke to our comprehensive stroke center between January 1, 2010, and November 30, 2016. Diagnosis of CeAD was based on clinical and radiological findings. Univariate and multivariable logistic regression analyses were used to assess the risk factors and clinical outcomes associated with CeAD-related strokes. RESULTS: Of the total 333 patients with acute ischemic stroke included in the study (mean ± SD age: 36.4 ± 7.1 years; women 50.8%), CeAD was identified in 79 (23.7%) patients. As compared to stroke due to other etiologies, patients with CeAD were younger in age, more likely to have history of migraine and recent neck manipulation and were less likely to have hypertension, diabetes, and previous history of stroke. Clinical outcomes of CeAD were comparable to strokes due to other etiologies. Within the CeAD group, higher initial stroke severity and history of tobacco use were associated with higher modified Rankin Scale score at follow-up. CONCLUSIONS: While history of migraine and neck manipulation are significantly associated with CeAD, most of the traditional vascular risk factors for stroke are less prevalent in this group when compared to strokes due to other etiologies. For CeAD-related strokes, higher initial stroke severity and history of tobacco use may be associated with higher stroke-related disability, but overall, patients with CeAD have similar outcomes as compared to strokes due to other etiologies.

Dual antiplatelet therapy in aneurysmal subarachnoid hemorrhage: association with reduced risk of clinical vasospasm and delayed cerebral ischemia.

OBJECTIVE Clinical vasospasm and delayed cerebral ischemia (DCI) are devastating complications of aneurysmal subarachnoid hemorrhage (aSAH). Several theories involving platelet activation have been postulated as potential explanations of the development of clinical vasospasm and DCI. However, the effects of dual antiplatelet therapy (DAPT; aspirin and clopidogrel) on clinical vasospasm and DCI have not been previously investigated. The objective of this study was to evaluate the effects of DAPT on clinical vasospasm and DCI in aSAH patients. METHODS Analysis of patients treated for aSAH during the period from July 2009 to April 2014 was performed in a single-institution retrospective study. Patients were divided into 2 groups: patients who underwent stent-assisted coiling or placement of flow diverters requiring DAPT (DAPT group) and patients who underwent coiling only without DAPT (control group). The frequency of symptomatic clinical vasospasm and DCI and of hemorrhagic complications was compared between the 2 groups, utilizing univariate and multivariate logistic regression. RESULTS Of 312 aSAH patients considered for this study, 161 met the criteria for inclusion and were included in the analysis (85 patients in the DAPT group and 76 patients in the control group). The risks of clinical vasospasm (OR 0.244, CI 95% 0.097-0.615, p = 0.003) and DCI (OR 0.056, CI 95% 0.01-0.318, p = 0.001) were significantly lower in patients receiving DAPT. The rates of hemorrhagic complications associated with placement of external ventricular drains and ventriculoperitoneal shunts were similar in both groups (4% vs 2%, p = 0.9). CONCLUSIONS The use of DAPT was associated with a lower risk of clinical vasospasm and DCI in patients treated for aSAH, without an increased risk of hemorrhagic complications.

Improving prediction of outcome in "good grade" subarachnoid hemorrhage.

OBJECTIVE: We hypothesize that subtle neurological signs at baseline could be present in some "good grade" subarachnoid hemorrhage (SAH) patients and that they would have negative prognostic implications. METHODS: We analyzed data from 1000 patients randomized to the Intraoperative Hypothermia for Aneurysm Surgery Trial (World Federation of Neurological Societies Grades I, II, and III). Nine hundred and forty-four patients had a complete National Institutes of Health Stroke Scale (NIHSS) examination performed at baseline. We analyzed the relationship between baseline NIHSS scores and Glasgow Outcome Scale scores at 3 months. Using stepwise logistic regression, we identified the individual NIHSS items that independently predicted outcome to construct a useful shorter version of the scale for SAH. RESULTS: The NIHSS was abnormal at baseline in 23% of the Grade I patients and 82% of the Grade II patients. Baseline NIHSS scores strongly predicted 3-month outcomes (P < 0.001). The NIHSS items that were relevant to predict outcome were level of consciousness, dysarthria, visual fields, and worst motor score for the arms. Baseline NIHSS-SAH scores also independently predicted 3-month outcomes (P < 0.001). CONCLUSION: Subtle neurological signs at baseline are common in World Federation of Neurological Societies Grades I and II patients and are associated with a worse outcome at 3 months. These signs are not detected by the World Federation of Neurological Societies classification. A better stratification of "good grade" SAH patients to predict long-term outcomes may be desirable for clinical trials and practice. Either using the full NIHSS or a shortened version testing level of consciousness, visual fields, dysarthria and worst arm motor score will help to better stratify "good-grade" SAH patients.

Cerebral air embolism secondary to intra-aortic balloon pump rupture.

INTRODUCTION: Cerebral air embolism is a neurological emergency. It has been reported following cardiac catheterization, central venous catheter insertion, and cardiothoracic surgery. METHODS AND RESULTS: We report a case of massive cerebral air embolism secondary to intra-aortic balloon pump (IABP) rupture. Computed tomography (CT) of the brain showed serpiginous hypodensities following the sulci associated with hypodense brain parenchymal lesions. CONCLUSION: The prompt recognition of cerebral air embolism secondary to IABP rupture requires a high level of suspicion and is confirmed by head CT.