Extended Middle Cerebral Artery Occlusion (MCAO) Model to Mirror Stroke Patients Undergoing Thrombectomy.

Stroke remains a leading global cause of death and disability. In the last decade, the therapeutic window for mechanical thrombectomy has increased from a maximum of 6 to 24 h and beyond. While endovascular advancements have improved rates of recanalization, no post-stroke pharmacotherapeutics have been effective in enhancing neurorepair and recovery. New experimental models are needed to closer mimic the human patient. Our group has developed a model of transient 5-h occlusion in rats to mimic stroke patients undergoing thrombectomy. Our procedure was designed specifically in aged rats and was optimized based on sex in order to keep mortality and extent of injury consistent between aged male and female rats. This model uses a neurological assessment modeled after the NIH Stroke Scale. Finally, the potential for translation between our rat model of stroke and humans was assessed using comparative gene expression for key inflammatory genes. This model will be useful in the evaluation of therapeutic targets to develop adjuvant treatments for large vessel occlusion during the thrombectomy procedure.

Smoking-Induced Sex Differences in Clinical Outcomes in Patients Undergoing Mechanical Thrombectomy for Stroke.

OBJECTIVE: Ischemic stroke is the fifth leading cause of death in the United States. Smoking accelerates the onset of stroke by 10 years. The effects of smoking status on percent change in National Institutes of Health Stroke Scale (NIHSS) score, infarct volume, and edema volume were examined following mechanical thrombectomy for large vessel occlusion in patients with acute ischemic stroke. METHODS: Subjects (N = 90; >18 years old) were divided into 3 groups based on smoking status: current smokers, previous smokers (defined as having quit >6 months before the ischemic event), and nonsmokers. Percent change in NIHSS score was defined as score at admission minus score at discharge divided by score at admission and was used as a predictor of functional outcome. Linear regression analysis was performed based on infarct or edema volume versus percent change in NIHSS score and separated by sex. RESULTS: Consistent with previous findings, smokers experienced a stroke 10 years earlier than nonsmokers (P = 0.004). Statistically significant linear regressions existed between infarct volume or edema volume in relation to worsening change in NIHSS score with female smokers only. Stroke-induced tissue damage, as measured by magnetic resonance imaging or computed tomography, was predictive of functional recovery only in female smokers. CONCLUSIONS: These findings are valuable for patient counseling, particularly for women, for smoking cessation.

Integrin α5ß1 inhibition by ATN-161 reduces neuroinflammation and is neuroprotective in ischemic stroke.

Stroke remains a leading cause of death and disability with limited therapeutic options. Endothelial cell ß1 integrin receptors play a direct role in blood-brain barrier (BBB) dysfunction through regulation of tight junction proteins and infiltrating leukocytes, potentially mediated by ß1 integrins. Following tandem transient common carotid artery/middle cerebral artery occlusion on wild-type mice, we administered the integrin a5b1 inhibitor, ATN-161, intraperitoneal (IP) injection at 1 mg/kg acutely after reperfusion, on post-stroke day (PSD)1 and PSD2. Systemic changes (heart rate, pulse distension, and body temperature) were determined. Additionally, infarct volume and edema were determined by 2,3-triphenyltetrazolium chloride and magnetic resonance imaging, while neurological changes were evaluated using an 11-point Neuroscore. Brain immunohistochemistry was performed for claudin-5, α5ß1, IgG, and CD45 + cells, and quantitative polymerase chain reaction (qPCR) was performed for matrix metalloproteinase-9 (MMP-9), interleukin (IL)-1ß, collagen IV, and CXCL12. ATN-161 significantly reduced integrin α5ß1 expression in the surrounding peri-infarct region with no systemic changes. Infarct volume, edema, and functional deficit were significantly reduced in ATN-161-treated mice. Furthermore, ATN-161 treatment reduced IgG extravasation into the parenchyma through conserved claudin-5, collagen IV, CXCL12 while reducing MMP-9 transcription. Additionally, IL-1ß and CD45 + cells were reduced in the ipsilateral cortex following ATN-161 administration. Collectively, ATN-161 may be a promising novel stroke therapy by reducing post-stroke inflammation and BBB permeability.

Efficacy of leukemia inhibitory factor as a therapeutic for permanent large vessel stroke differs among aged male and female rats.

Preclinical studies using rodent models of stroke have had difficulty in translating their results to human patients. One possible factor behind this inability is the lack of studies utilizing aged rodents of both sexes. Previously, this lab showed that leukemia inhibitory factor (LIF) promoted recovery after stroke through antioxidant enzyme upregulation. This study examined whether LIF promotes neuroprotection in aged rats of both sexes. LIF did not reduce tissue damage in aged animals, but LIF-treated female rats showed partial motor skill recovery. The LIF receptor (LIFR) showed membrane localization in young male and aged rats of both sexes after stroke. Although LIF increased neuronal LIFR expression in vitro, it did not increase LIFR in the aged brain. Levels of LIFR protein in brain tissue were significantly downregulated between young males and aged males/females at 72 h after stroke. These results demonstrated that low LIFR expression reduces the neuroprotective efficacy of LIF in aged rodents of both sexes. Furthermore, the ability of LIF to promote motor improvement is dependent upon sex in aged rodents.

The Blood And Clot Thrombectomy Registry And Collaboration (BACTRAC) protocol: novel method for evaluating human stroke.

BACKGROUND: Ischemic stroke research faces difficulties in translating pathology between animal models and human patients to develop treatments. Mechanical thrombectomy, for the first time, offers a momentary window into the changes occurring in ischemia. We developed a tissue banking protocol to capture intracranial thrombi and the blood immediately proximal and distal to it. OBJECTIVE: To develop and share a reproducible protocol to bank these specimens for future analysis. METHODS: We established a protocol approved by the institutional review board for tissue processing during thrombectomy (www.clinicaltrials.gov NCT03153683). The protocol was a joint clinical/basic science effort among multiple laboratories and the NeuroInterventional Radiology service line. We constructed a workspace in the angiography suite, and developed a step-by-step process for specimen retrieval and processing. RESULTS: Our protocol successfully yielded samples for analysis in all but one case. In our preliminary dataset, the process produced adequate amounts of tissue from distal blood, proximal blood, and thrombi for gene expression and proteomics analyses. We describe the tissue banking protocol, and highlight training protocols and mechanics of on-call research staffing. In addition, preliminary integrity analyses demonstrated high-quality yields for RNA and protein. CONCLUSIONS: We have developed a novel tissue banking protocol using mechanical thrombectomy to capture thrombus along with arterial blood proximal and distal to it. The protocol provides high-quality specimens, facilitating analysis of the initial molecular response to ischemic stroke in the human condition for the first time. This approach will permit reverse translation to animal models for treatment development.

Targeted therapy for infants with diencephalic syndrome: A case report and review of management strategies.

Young children with emaciation caused by a hypothalamic glioma are considered to have diencephalic syndrome (DS), which is often poorly controlled with conventional treatment. We describe an infant with DS whose tumor progressed following chemotherapy. Biopsy was performed for molecular testing and demonstrated a BRAF fusion. Treatment with the MEK inhibitor trametinib for 18 months resulted in reduction of tumor size, normalization of his weight curve, and marked neurodevelopmental improvement. Our results build on earlier reports of using targeted agents for low-grade glioma, and we review the evolving management strategy for such patients in the era of precision medicine.