Preclinical evaluation of circadian rhythm in ischemic stroke outcomes

Stroke is a leading cause of disability and death worldwide. There is evidence that there is a circadian rhythm in stroke with peak occurrence in the morning (6 to 10 am). However, it is not clear if the size of infarcts and the outcome of stroke also varies during the 24-hour period. We hypothesized that the size of cerebral infarct and outcome from stroke would show circadian variation in a mouse suture occlusion model. Seven to eight-month-old C57BL/6J (n =10-12 mice/group) mice were randomly assigned to undergo middle cerebral artery occlusion (MCAO) for 60 minutes at different time points during the 24h day following zeitgeber time at ZT0, ZT6, ZT12, and Z18. Cerebral blood flow was monitored by Laser Speckle Contrast Imaging at baseline after occlusion, and again at 24h post-occlusion. Neurological deficit was observed by using Bederson score at 24h and 48h. The corner test was used to detect unilateral abnormalities in sensory and motor functions in the stroke mice at 48h. To estimate brain infarction, 2,3,5-tryphenyltetrazolium chloride staining was performed 48h after stroke and the infarct area was quantified using NIH-Image J software. We did not find a significant difference in cerebral blood flow at any time point. There was a significant decrease in neurological deficit as assessed using the Bederson Score from 24h (1.82 ± 1.11) to 48h (1.10 ± 0.12) in the ZT18 (midnight) period (p = 0.0025), however there were no differences between groups at 48h. In the corner test, we found right turn preference significantly higher (p = 0.0348) at noon/ZT06 (9.5 ± 1.06) compared to the fully awake (5.5 ± 4.06) (midnight, ZT18) period and ZT0 (6 am, 4.8 ± 0.97, p = 0.0087). Similarly, the infarction volume was significantly higher (p = 0.0220) during the sleep (ZT06, noon) period (35.22 ± 20.77) than when the ischemic mice were fully awake during the midnight/ZT18 period (15.68 ± 7.54). This is the first report demonstrating that mice have larger infarcts and worse short-term outcomes during their sleep period (noon/ZT06) than during their awake period (midnight/ZT18).

Profound Racial Disparities in COVID-19 Associated Hospitalizations in Rural Southwest Georgia

Background

The coronavirus disease 2019 (COVID-19) is responsible for one of the largest public health crises the United States has seen to date. This study explores the outcomes of African American and non-African American COVID-19-positive patients hospitalized in rural Southwest Georgia to identify differences in morbidity and mortality between the groups.

Methods

We performed a retrospective cohort analysis among adults aged ≥18 years admitted with COVID-19 between March 2, 2020 and June 17, 2020 at Phoebe Putney Health System. Data on demographics, comorbidities, presenting symptoms, and hospital course were obtained. Patients were divided into two groups: African Americans and non-African Americans. We examined differences in patient characteristics between groups using chi-square tests for categorical variables, t-test for parametric continuous variables, and Wilcoxon rank-sum tests for non-parametric continuous variables. Statistical Analysis Software (SAS) version 9.4 was used for statistical analysis.

Results

Among 710 patients, median age was 63 years, 43.8% were males, and 83.3% were African Americans. African Americans had higher prevalence of obesity and hypertension, were more likely to present with fever, and present with longer duration of symptoms prior to presentation. In-hospital mortality was similar between the groups, as was need for mechanical ventilation, ICU care, and new dialysis. African Americans were more likely to be discharged home compared to non-African Americans.

Conclusions

There was no difference in in-hospital mortality; however, African Americans had disproportionately higher hospitalizations, likely to significantly increase the morbidity burden in this population. Urgent measures are needed to address this profound racial disparity.

Rescuing mitochondria in traumatic brain injury and intracerebral hemorrhages - A potential therapeutic approach

Mitochondria are dynamic organelles responsible for cellular energy production. Besides, regulating energy homeostasis, mitochondria are responsible for calcium homeostasis, signal transmission, and the fate of cellular survival in case of injury and pathologies. Accumulating reports have suggested multiple roles of mitochondria in neuropathologies, neurodegeneration, and immune activation under physiological and pathological conditions. Mitochondrial dysfunction, which occurs at the initial phase of brain injury, involves oxidative stress, inflammation, deficits in mitochondrial bioenergetics, biogenesis, transport, and autophagy. Thus, development of targeted therapeutics to protect mitochondria may improve functional outcomes following traumatic brain injury (TBI) and intracerebral hemorrhages (ICH). In this review, we summarize mitochondrial dysfunction related to TBI and ICH, including the mechanisms involved, and discuss therapeutic approaches with special emphasis on past and current clinical trials.

Mechanisms of Preconditioning Exercise-Induced Neurovascular Protection in Stroke

Ischemic stroke is a leading cause of death and disability. Tissue plasminogen activator is the only U.S. Food and Drug Administration approved thrombolytic therapy for ischemic stroke patients till date. However, its use is limited due to increased risk of bleeding and narrow therapeutic window. Most of the preclinically tested pharmacological agents failed to be translated to the clinic. This drives the need for alternative therapeutic approaches that not only provide enhanced neuroprotection, but also reduce the risk of stroke. Physical exercise is a sort of preconditioning that provides the body with brief ischemic episodes that can protect the body from subsequent severe ischemic attacks like stroke. Physical exercise is known to improve cardiovascular health. However, its role in providing neuroprotection in stroke is not clear. Clinical observational studies showed a correlation between regular physical exercise and reduced risk and severity of ischemic stroke and better outcomes after stroke. However, the underlying mechanisms through which prestroke exercise can reduce the stroke injury and improve the outcomes are not completely understood. The purpose of this review is to: demonstrate the impact of exercise on stroke outcomes and show the potential role of exercise in stroke prevention and recovery; uncover the underlying mechanisms through which exercise reduces the neurovascular injury and improves stroke outcomes aiming to develop novel therapeutic approaches.

A potential role for cannabichromene in modulating TRP channels during acute respiratory distress syndrome

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a life-threatening clinical syndrome whose potential to become one of the most grievous challenges of the healthcare system evidenced by the COVID-19 pandemic. Considering the lack of target-specific treatment for ARDS, it is absolutely exigent to have an effective therapeutic modality to reduce hospitalization and mortality rate as well as to improve quality of life and outcomes for ARDS patients. ARDS is a systemic inflammatory disease starting with the pulmonary system and involves all other organs in a morbid bidirectional fashion. Mounting evidence including our findings supporting the notion that cannabinoids have potential to be targeted as regulatory therapeutic modalities in the treatment of inflammatory diseases. Therefore, it is plausible to test their capabilities as alternative therapies in the treatment of ARDS. In this study, we investigated the potential protective effects of cannabichromene (CBC) in an experimental model of ARDS.

METHODS

We used, for the first time, an inhalant CBC treatment as a potential therapeutic target in a murine model of ARDS-like symptoms. ARDS was induced by intranasal administration of Poly(I:C), a synthetic mismatched double-stranded RNA, into the C57BL/6 mice (6-10 male mice/group, including sham, placebo, and CBC treated), three once-daily doses followed by a daily dose of inhalant CBC or placebo for the period of 8 days starting the first dose 2 h after the second Poly(I:C) treatment. We employed histologic, immunohistochemistry, and flow cytometry methods to assess the findings. Statistical analysis was performed by using one way analysis of variance (ANOVA) followed by Newman-Keuls post hoc test to determine the differences among the means of all experimental groups and to establish significance (p < 0.05) among all groups.

RESULTS

Our data showed that CBC was able to reverse the hypoxia (increasing blood O₂ saturation by 8%), ameliorate the symptoms of ARDS (reducing the pro-inflammatory cytokines by 50% in lung and blood), and protect the lung tissues from further destruction. Further analysis showed that CBC may wield its protective effects through transient receptor potential (TRP) cation channels, TRPA1 and TRPV1, increasing their expression by 5-folds in lung tissues compared to sham and untreated mice, re-establishing the homeostasis and immune balance.

CONCLUSION

Our findings suggest that inhalant CBC may be an effective alternative therapeutic target in the treatment of ARDS. In addition, Increased expression of TRPs cation channels after CBC treatment proposes a novel role for TRPs (TRPA1 and TRPV2) as new potential mechanism to interpret the beneficial effects of CBC as well as other cannabinoids in the treatment of ARDS as well as other inflammatory diseases. Importantly, delivering CBC through an inhaler device is a translational model supporting the feasibility of trial with human subjects, authorizing further research.

Cannabidiol Ameliorates Cognitive Function via Regulation of IL-33 and TREM2 Upregulation in a Murine Model of Alzheimer's Disease

There is a dire need for due innovative therapeutic modalities to improve outcomes of AD patients. In this study, we tested whether cannabidiol (CBD) improves outcomes in a translational model of familial AD and to investigate if CBD regulates interleukin (IL)-33 and triggering receptor expressed on myeloid cells 2 (TREM2), which are associated with improved cognitive function. CBD was administered to 5xFAD mice, which recapitulate early onset, familial AD. Behavioral tests and immunoassays were used to evaluate cognitive and motor outcomes. Our findings suggest that CBD treatment enhanced IL-33 and TREM2 expression, ameliorated the symptoms of AD, and retarded cognitive decline.

AIM2 inflammasome mediates hallmark neuropathological alterations and cognitive impairment in a mouse model of vascular dementia

Chronic cerebral hypoperfusion is associated with vascular dementia (VaD). Cerebral hypoperfusion may initiate complex molecular and cellular inflammatory pathways that contribute to long-term cognitive impairment and memory loss. Here we used a bilateral common carotid artery stenosis (BCAS) mouse model of VaD to investigate its effect on the innate immune response-particularly the inflammasome signaling pathway. Comprehensive analyses revealed that chronic cerebral hypoperfusion induces a complex temporal expression and activation of inflammasome components and their downstream products (IL-1β and IL-18) in different brain regions, and promotes activation of apoptotic and pyroptotic cell death pathways. Polarized glial-cell activation, white-matter lesion formation and hippocampal neuronal loss also occurred in a spatiotemporal manner. Moreover, in AIM2 knockout mice we observed attenuated inflammasome-mediated production of proinflammatory cytokines, apoptosis, and pyroptosis, as well as resistance to chronic microglial activation, myelin breakdown, hippocampal neuronal loss, and behavioral and cognitive deficits following BCAS. Hence, we have demonstrated that activation of the AIM2 inflammasome substantially contributes to the pathophysiology of chronic cerebral hypoperfusion-induced brain injury and may therefore represent a promising therapeutic target for attenuating cognitive impairment in VaD.

A County-Level Analysis of Socioeconomic and Clinical Predictors of COVID-19 Incidence and Case-Fatality Rates in Georgia, March-September 2020

OBJECTIVES

The global COVID-19 pandemic has affected various populations differently. We investigated the relationship between socioeconomic determinants of health obtained from the Robert Wood Johnson Foundation County Health Rankings and COVID-19 incidence and mortality at the county level in Georgia.

METHODS

We analyzed data on COVID-19 incidence and case-fatality rates (CFRs) from the Georgia Department of Public Health from March 1 through August 31, 2020. We used repeated measures generalized linear mixed models to determine differences over time in Georgia counties among quartile health rankings of health outcomes, health behaviors, clinical care, social and economic factors, and physical environment.

RESULTS

COVID-19 incidence per 100 000 population increased across all quartile county groups for all health rankings (range, 23.1-51.6 in May to 688.4-1062.0 in August). COVID-19 CFRs per 100 000 population peaked in April and May (range, 3312-6835) for all health rankings, declined in June and July (range, 827-5202), and increased again in August (range, 1877-3310). Peak CFRs occurred later in counties with low health rankings for health behavior and clinical care and in counties with high health rankings for social and economic factors and physical environment. All interactions between the health ranking quartile variables and month were significant (P < .001). County-level Gini indices were associated with significantly higher rates of COVID-19 incidence (P < .001) but not CFRs.

CONCLUSIONS

From March through August 2020, COVID-19 incidence rose in Georgia's counties independent of health rankings categorization. Differences in time to peak CFRs differed at the county level based upon key health rankings. Public health interventions should incorporate unique strategies to improve COVID-19-related patient outcomes in these environments.

Conditioning medicine for ischemic and hemorrhagic stroke

Remote ischemic conditioning (RIC) is a promising safe, feasible, and inexpensive treatment for acute stroke, both ischemic and hemorrhagic. It is applied with a blood pressure cuff on the limbs and is ideal for the prehospital setting. RIC is a form of preconditioning with similarities to physical exercise. Its mechanisms of action are multiple and include improvement of collateral cerebral blood flow (CBF) and RIC acts as a "collateral therapeutic". The increased CBF is likely related to nitric oxide synthase 3 in the endothelium and more importantly in circulating blood cells like the red blood cell. The RESIST clinical trial is a 1500 subject multicenter, randomized, sham-controlled trial of RIC in the prehospital setting in Denmark and should address the questions of whether RIC is safe and effective in acute stroke and whether the effect is mediated by an effect on nitric oxide/nitrite metabolism.

Decreased parenchymal arteriolar tone uncouples vessel-to-neuronal communication in a mouse model of vascular cognitive impairment

Chronic hypoperfusion is a key contributor to cognitive decline and neurodegenerative conditions, but the cellular mechanisms remain ill-defined. Using a multidisciplinary approach, we sought to elucidate chronic hypoperfusion-evoked functional changes at the neurovascular unit. We used bilateral common carotid artery stenosis (BCAS), a well-established model of vascular cognitive impairment, combined with an ex vivo preparation that allows pressurization of parenchymal arterioles in a brain slice. Our results demonstrate that mild (~ 30%), chronic hypoperfusion significantly altered the functional integrity of the cortical neurovascular unit. Although pial cerebral perfusion recovered over time, parenchymal arterioles progressively lost tone, exhibiting significant reductions by day 28 post-surgery. We provide supportive evidence for reduced adenosine 1 receptor-mediated vasoconstriction as a potential mechanism in the adaptive response underlying the reduced baseline tone in parenchymal arterioles. In addition, we show that in response to the neuromodulator adenosine, the action potential frequency of cortical pyramidal neurons was significantly reduced in all groups. However, a significant decrease in adenosine-induced hyperpolarization was observed in BCAS 14 days. At the microvascular level, constriction-induced inhibition of pyramidal neurons was significantly compromised in BCAS mice. Collectively, these results suggest that BCAS uncouples vessel-to-neuron communication-vasculo-neuronal coupling-a potential early event in cognitive decline.

The Immunomodulatory Capacity of Induced Pluripotent Stem Cells in the Post-stroke Environment

Inflammation has proven to be a key contributing factor to the pathogenesis of ischemic and hemorrhagic stroke. This sequential and progressive response, marked by proliferation of resident immune cells and recruitment of peripheral immune populations, results in increased oxidative stress, and neuronal cell death. Therapeutics aimed at quelling various stages of this post-stroke inflammatory response have shown promise recently, one of which being differentiated induced pluripotent stem cells (iPSCs). While direct repopulation of damaged tissues and enhanced neurogenesis are hypothesized to encompass some of the therapeutic potential of iPSCs, recent evidence has demonstrated a substantial paracrine effect on neuroinflammation. Specifically, investigation of iPSCs, iPSC-neural progenitor cells (iPSC-NPCs), and iPSC-neuroepithelial like stem cells (iPSC-lt-NESC) has demonstrated significant immunomodulation of proinflammatory signaling and endogenous inflammatory cell populations, such as microglia. This review aims to examine the mechanisms by which iPSCs mediate neuroinflammation in the post-stroke environment, as well as delineate avenues for further investigation.

Altered mental status is an independent predictor of mortality in hospitalized COVID-19 patients

BACKGROUND/AIMS

Limited data exists on the outcomes of COVID-19 patients presenting with altered mental status (AMS). Hence, we studied the characteristics and outcomes of hospitalized COVID-19 patients who presented with AMS at our hospital in rural southwest Georgia.

METHODS

Data from electronic medical records of all hospitalized COVID-19 patients from March 2, 2020, to June 17, 2020, were analyzed. Patients were divided in 2 groups, those presenting with and without AMS. Primary outcome of interest was in-hospital mortality. Secondary outcomes were needed for mechanical ventilation, need for intensive care unit (ICU) care, need for dialysis, and length of stay. All analyses were performed using SAS 9.4 and R 3.6.0.

RESULTS

Out of 710 patients, 73 (10.3%) presented with AMS. Majority of the population was African American (83.4%). Patients with AMS were older and more likely to have hypertension, chronic kidney disease (CKD), cerebrovascular disease, and dementia. Patients with AMS were less likely to present with typical COVID-19 symptoms, including dyspnea, cough, fever, and gastrointestinal symptoms. Predictors of AMS included age ≥ 70 years, CKD, cerebrovascular disease, and dementia. After multivariable adjustment, patients with AMS had higher rates of in-hospital mortality (30.1% vs 14.8%, odds ratio (OR) 2.139, p = 0.019), ICU admission (43.8% vs 40.2%, OR 2.59, p < 0.001), and need for mechanical ventilation (27.4% vs 18.5%, OR 2.06, p = 0.023). Patients presenting with AMS had increased length of stay.

CONCLUSIONS

Patients with COVID-19 presenting with AMS are less likely to have typical COVID-19 symptoms, and AMS is an independent predictor of in-hospital mortality, need for ICU admission, and need for mechanical ventilation.

AMPK induces regulatory innate lymphoid cells after traumatic brain injury

The CNS is regarded as an immunoprivileged organ, evading routine immune surveillance; however, the coordinated development of immune responses profoundly influences outcomes after brain injury. Innate lymphoid cells (ILCs) are cytokine-producing cells that are critical for the initiation, modulation, and resolution of inflammation, but the functional relevance and mechanistic regulation of ILCs are unexplored after acute brain injury. We demonstrate increased proliferation of all ILC subtypes within the meninges for up to 1 year after experimental traumatic brain injury (TBI) while ILCs were present within resected dura and elevated within cerebrospinal fluid (CSF) of moderate-to-severe TBI patients. In line with energetic derangements after TBI, inhibition of the metabolic regulator, AMPK, increased meningeal ILC expansion, whereas AMPK activation suppressed proinflammatory ILC1/ILC3 and increased the frequency of IL-10-expressing ILC2 after TBI. Moreover, intracisternal administration of IL-33 activated AMPK, expanded ILC2, and suppressed ILC1 and ILC3 within the meninges of WT and Rag1-/- mice, but not Rag1-/- IL2rg-/- mice. Taken together, we identify AMPK as a brake on the expansion of proinflammatory, CNS-resident ILCs after brain injury. These findings establish a mechanistic framework whereby immunometabolic modulation of ILCs may direct the specificity, timing, and magnitude of cerebral immunity.

Cannabidiol (CBD) modulation of apelin in acute respiratory distress syndrome

Considering lack of target-specific antiviral treatment and vaccination for COVID-19, it is absolutely exigent to have an effective therapeutic modality to reduce hospitalization and mortality rate as well as to improve COVID-19-infected patient outcomes. In a follow-up study to our recent findings indicating the potential of Cannabidiol (CBD) in the treatment of acute respiratory distress syndrome (ARDS), here we show for the first time that CBD may ameliorate the symptoms of ARDS through up-regulation of apelin, a peptide with significant role in the central and peripheral regulation of immunity, CNS, metabolic and cardiovascular system. By administering intranasal Poly (I:C), a synthetic viral dsRNA, while we were able to mimic the symptoms of ARDS in a murine model, interestingly, there was a significant decrease in the expression of apelin in both blood and lung tissues. CBD treatment was able to reverse the symptoms of ARDS towards a normal level. Importantly, CBD treatment increased the apelin expression significantly, suggesting a potential crosstalk between apelinergic system and CBD may be the therapeutic target in the treatment of inflammatory diseases such as COVID-19 and many other pathologic conditions.

COVID-19 and neurological symptoms: is the SARS-CoV-2 virus neurotropic?

IMPORTANCE

The most notable symptoms of the Coronavirus Disease 2019 (COVID-19) pandemic are fever, cough, dyspnea, and in severe cases, adult respiratory distress syndrome (ARDS.) But neurological symptoms including confusion, stroke, and encephalopathy are reported, and anosmia and hypogeusia are also common indicating that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may be neurotropic.

OBSERVATIONS

The SARS-Co-1 and 2 viruses bind to angiotensin converting enzyme 2 (ACE2), which is present on human brain endothelium and non-neuronal cells in the nasopharynx and lingual epithelium. However, SARS-CoV-1 and 2 do not bind rodent ACE2 avidly, which has required the generation of humanized ACE2 transgenic animal models of disease. Transgenic mouse models suggest that the SARS- CoV-1 and Middle East respiratory syndrome (MERS)-CoV are neurotropic and infect and damage the brain, including the cardiorespiratory centers in the medulla. The symptoms of anosmia and hypogeusia indicate a portal to the brain. The relationship between encephalitis lethargica and post encephalitis parkinsonism to the Spanish Flu (H1N1 influenza virus) is unclear but raises the question of long term neurological complications of pandemics.

CONCLUSIONS AND RELEVANCE

There is a concern that there may be long term neurological sequelae of infection with SARS-CoV-2. Registries and long term neurological follow up with longitudinal cohort studies of COVID19 positive patients are needed.

Neurological consequences of COVID-19: what have we learned and where do we go from here?

The coronavirus disease-19 (COVID-19) pandemic is an unprecedented worldwide health crisis. COVID-19 is caused by SARS-CoV-2, a highly infectious pathogen that is genetically similar to SARS-CoV. Similar to other recent coronavirus outbreaks, including SARS and MERS, SARS-CoV-2 infected patients typically present with fever, dry cough, fatigue, and lower respiratory system dysfunction, including high rates of pneumonia and acute respiratory distress syndrome (ARDS); however, a rapidly accumulating set of clinical studies revealed atypical symptoms of COVID-19 that involve neurological signs, including headaches, anosmia, nausea, dysgeusia, damage to respiratory centers, and cerebral infarction. These unexpected findings may provide important clues regarding the pathological sequela of SARS-CoV-2 infection. Moreover, no efficacious therapies or vaccines are currently available, complicating the clinical management of COVID-19 patients and emphasizing the public health need for controlled, hypothesis-driven experimental studies to provide a framework for therapeutic development. In this mini-review, we summarize the current body of literature regarding the central nervous system (CNS) effects of SARS-CoV-2 and discuss several potential targets for therapeutic development to reduce neurological consequences in COVID-19 patients.

Cannabidiol Modulates Cytokine Storm in Acute Respiratory Distress Syndrome Induced by Simulated Viral Infection Using Synthetic RNA

Introduction: In the absence of effective antivirals and vaccination, the pandemic of COVID-19 remains the most significant challenge to our health care system in decades. There is an urgent need for definitive therapeutic intervention. Clinical reports indicate that the cytokine storm associated with acute respiratory distress syndrome (ARDS) is the leading cause of mortality in severe cases of some respiratory viral infections, including COVID-19. In recent years, cannabinoids have been investigated extensively due to their potential effects on the human body. Among all cannabinoids, cannabidiol (CBD) has demonstrated potent anti-inflammatory effects in a variety of pathological conditions. Therefore, it is logical to explore whether CBD can reduce the cytokine storm and treat ARDS. Materials and Methods: In this study, we show that intranasal application of Poly(I:C), a synthetic analogue of viral double-stranded RNA, simulated symptoms of severe viral infections inducing signs of ARDS and cytokine storm. Discussion: The administration of CBD downregulated the level of proinflammatory cytokines and ameliorated the clinical symptoms of Poly I:C-induced ARDS. Conclusion: Our results suggest a potential protective role for CBD during ARDS that may extend CBD as part of the treatment of COVID-19 by reducing the cytokine storm, protecting pulmonary tissues, and re-establishing inflammatory homeostasis.

COVID-19-Related Stroke

The COVID-19 pandemic is associated with neurological symptoms and complications including stroke. There is hypercoagulability associated with COVID-19 that is likely a "sepsis-induced coagulopathy" and may predispose to stroke. The SARS-CoV-2 virus binds to angiotensin-converting enzyme 2 (ACE2) present on brain endothelial and smooth muscle cells. ACE2 is a key part of the renin angiotensin system (RAS) and a counterbalance to angiotensin-converting enzyme 1 (ACE1) and angiotensin II. Angiotensin II is proinflammatory, is vasoconstrictive, and promotes organ damage. Depletion of ACE2 by SARS-CoV-2 may tip the balance in favor of the "harmful" ACE1/angiotensin II axis and promote tissue injury including stroke. There is a rationale to continue to treat with tissue plasminogen activator for COVID-19-related stroke and low molecular weight heparinoids may reduce thrombosis and mortality in sepsis-induced coagulopathy.

Neutrophil extracellular traps exacerbate neurological deficits after traumatic brain injury

Traumatic brain injury (TBI) is a major cause of mortality and morbidity. Preventative measures reduce injury incidence and/or severity, yet one-third of hospitalized patients with TBI die from secondary pathological processes that develop during supervised care. Neutrophils, which orchestrate innate immune responses, worsen TBI outcomes via undefined mechanisms. We hypothesized that formation of neutrophil extracellular traps (NETs), a purported mechanism of microbial trapping, exacerbates acute neurological injury after TBI. NET formation coincided with cerebral hypoperfusion and tissue hypoxia after experimental TBI, while elevated circulating NETs correlated with reduced serum deoxyribonuclease-1 (DNase-I) activity in patients with TBI. Functionally, Toll-like receptor 4 (TLR4) and the downstream kinase peptidylarginine deiminase 4 (PAD4) mediated NET formation and cerebrovascular dysfunction after TBI. Last, recombinant human DNase-I degraded NETs and improved neurological function. Thus, therapeutically targeting NETs may provide a mechanistically innovative approach to improve TBI outcomes without the associated risks of global neutrophil depletion.

Impact of Participation in a Telestroke Network on Clinical Outcomes

BACKGROUND

A telestroke program, known as the Remote Evaluation for Acute Ischemic Stroke program, has been implemented in Georgia since 2003. This study examined whether a hospital's participation in a telestroke network was associated with improvement in clinical outcomes and quality indicators.

METHODS AND RESULTS

An observational study was conducted using data from the Georgia Coverdell Acute Stroke Registry between September 2005 and September 2016 for patients aged ≥18 years with ischemic stroke. We use a difference-in-differences approach to compare the following clinical outcomes and quality indicators among those admitted at hospitals within and outside of the Remote Evaluation for Acute Ischemic Stroke network: tPA (tissue-type plasminogen activator) use, complications related to tPA use, door-to-needle time, ambulation at discharge, discharge status, and destination. Logistic regression models and a propensity score weighting approach were performed to adjust for patients' age, sex, race, insurance coverage, arrival mode, ambulatory status before the current stroke, stroke severity, medical history, admission time, and hospital bed size. A total of 25 494 patients with ischemic stroke admitted at 15 nonteaching hospitals located outside of the Atlanta metropolitan area were included in the analysis. After propensity score weighting, hospitals participated in a telestroke network was not associated with a significant increase in the rate of tPA use, while it was significantly associated with a modest decline in the rate of complications related to tPA (-5.9%; 95% CI, -9.2% to -2.6%). Telestroke participation showed no significant difference in other clinical outcomes and quality measures except for a marginally significant decrease in in-hospital mortality (-1.1%; 95% CI, -2.2% to -0.1%).

CONCLUSIONS

Although a slight decrease in tPA complication was observed among hospitals participating in the telestroke network, overall the impact of telestroke participation on a hospital's stroke care quality was not statistically significant based on our observational study.

Abstract WP480: Beneficial Effect of Chronic-Remote Ischemic Conditioning (C-RIC) is Dependent Upon Circulating Blood Cell NOS3 in a Vascular Cognitive Impairment and Dementia (VCID) Model

Background and Purpose: Chronic remote ischemic conditioning (C-RIC) is effective at improving cerebral blood flow (CBF) inducing vascular remodeling, and improving cognition in a bilateral carotid artery stenosis (BCAS) mouse model, a model for Vascular Cognitive Impairment and Dementia (VCID). This effect is lost in NOS3-KO mice. We wanted to determine if the beneficial effect of C-RIC can be restored by bone marrow cell-derived NOS3.

Methods: We prepared BM chimera from adult WT (B6.SJL-Ptprc a ; CD45.1) to adult NOS3-KO (B6.129; CD45.2) & vice versa in male mice (5-6 months) following confirmation for BM engrafting with flow cytometry at 2 weeks. Microcoil (0.18 mm) induced BCAS model was used to induce chronic hypoperfusion. Mice were randomly assigned to 3-groups: (1) Sham (2) BCAS and (3) BCAS+RIC. RIC was started 7d post-surgery daily for 3-4 weeks. Behavioral test and CBF was performed before termination. Functional outcomes were assessed using novel object recognition (NOR) test for non-spatial working memory, and hanging wire and beam walk test for motor/muscular impairment. We measured whole blood P-NOS3, P-AMPK and VEGFR2/CD31 by flow cytometry.

Results: C-RIC-therapy for 3-4 weeks improves CBF in engrafted BM of WT into NOS3-KO in the BCAS+RIC groups at both 2 weeks and 4 weeks compared to BCAS (Sham RIC groups).No effect of C-RIC was shown in engrafted BM of NOS3 into WT. There was significant change between the BCAS and BCAS+RIC groups in the functional outcomes and histopathological evidences also reflects major changing in the groups in the BM of WT into NOS3-KO mice. Whole blood P-NOS3, P-AMPK and VEGFR2/CD31 was increased by C-RIC. However, no effect was shown in the NOS3-KO into WT chimera.

Conclusions: The Beneficial effect of C-RIC is dependent upon bone marrow derived NOS3.Further studies are needed to determine if the red blood cell is the key cell carrying NOS3

Establishment of an internationally agreed minimum data set for acute telestroke

INTRODUCTION

Globally, the use of telestroke programmes for acute care is expanding. Currently, a standardised set of variables for enabling reliable international comparisons of telestroke programmes does not exist. The aim of the study was to establish a consensus-based, minimum dataset for acute telestroke to enable the reliable comparison of programmes, clinical management and patient outcomes.

METHODS

An initial scoping review of variables was conducted, supplemented by reaching out to colleagues leading some of these programmes in different countries. An international expert panel of clinicians, researchers and managers (n = 20) from the Australasia Pacific region, USA, UK and Europe was convened. A modified-Delphi technique was used to achieve consensus via online questionnaires, teleconferences and email.

RESULTS

Overall, 533 variables were initially identified and harmonised into 159 variables for the expert panel to review. The final dataset included 110 variables covering three themes (service configuration, consultations, patient information) and 12 categories: (1) details about telestroke network/programme (n = 12), (2) details about initiating hospital (n = 10), (3) telestroke consultation (n = 17), (4) patient characteristics (n = 7), (5) presentation to hospital (n = 5), (6) general clinical care within first 24 hours (n = 10), (7) thrombolysis treatment (n = 10), (8) endovascular treatment (n = 13), (9) neurosurgery treatment (n = 8), (10) processes of care beyond 24 hours (n = 7), (11) discharge information (n = 5), (12) post-discharge and follow-up data (n = 6).

DISCUSSION

The acute telestroke minimum dataset provides a recommended set of variables to systematically evaluate acute telestroke programmes in different countries. Adoption is recommended for new and existing services.