Racial Disparities in Blood Pressure at Time of Acute Ischemic Stroke Presentation: A Population Study.

BACKGROUND: Hypertension is a stroke risk factor with known disparities in prevalence and management between Black and White patients. We sought to identify if racial differences in presenting blood pressure (BP) during acute ischemic stroke exist. METHODS AND RESULTS: Adults with acute ischemic stroke presenting to an emergency department within 24 hours of last known normal during study epochs 2005, 2010, and 2015 within the Greater Cincinnati/Northern Kentucky Stroke Study were included. Demographics, histories, arrival BP, National Institutes of Health Stroke Scale score, and time from last known normal were collected. Multivariable linear regression was used to determine differences in mean BP between Black and White patients, adjusting for age, sex, National Institutes of Health Stroke Scale score, history of hypertension, hyperlipidemia, smoking, stroke, body mass index, and study epoch. Of 4048 patients, 853 Black and 3195 White patients were included. In adjusted analysis, Black patients had higher presenting systolic BP (161 mm Hg [95% CI, 159-164] versus 158 mm Hg [95% CI, 157-159], P<0.01), diastolic BP (86 mm Hg [95% CI, 85-88] versus 83 mm Hg [95% CI, 82-84], P<0.01), and mean arterial pressure (111 mm Hg [95% CI, 110-113] versus 108 mm Hg [95% CI, 107-109], P<0.01) compared with White patients. In adjusted subanalysis of patients <4.5 hours from last known normal, diastolic BP (88 mm Hg [95% CI, 86-90] versus 83 mm Hg [95% CI, 82-84], P<0.01) and mean arterial pressure (112 mm Hg [95% CI, 110-114] versus 108 mm Hg [95% CI, 107-109], P<0.01) were also higher in Black patients. CONCLUSIONS: This population-based study suggests differences in presenting BP between Black and White patients during acute ischemic stroke. Further study is needed to determine whether these differences influence clinical decision-making, outcome, or clinical trial eligibility.

Substance Use and Performance of Toxicology Screens in the Greater Cincinnati Northern Kentucky Stroke Study.

BACKGROUND: Though stroke risk factors such as substance use may vary with age, less is known about trends in substance use over time or about performance of toxicology screens in young adults with stroke. METHODS: Using the Greater Cincinnati Northern Kentucky Stroke Study, a population-based study in a 5-county region comprising 1.3 million people, we reported the frequency of documented substance use (cocaine/marijuana/opiates/other) obtained from electronic medical record review, overall and by race/gender subgroups among physician-adjudicated stroke events (ischemic and hemorrhagic) in adults 20 to 54 years of age. Secondary analyses included heavy alcohol use and cigarette smoking. Data were reported for 5 one-year periods spanning 22 years (1993/1994-2015), and trends over time were tested. For 2015, to evaluate factors associated with performance of toxicology screens, multiple logistic regression was performed. RESULTS: Overall, 2152 strokes were included: 74.5% were ischemic, mean age was 45.7±7.6, 50.0% were women, and 35.9% were Black. Substance use was documented in 4.4%, 10.4%, 19.2%, 24.0%, and 28.8% of cases in 1993/1994, 1999, 2005, 2010, and 2015, respectively (Ptrend<0.001). Between 1993/1994 and 2015, documented substance use increased in all demographic subgroups. Adjusting for gender, comorbidities, and National Institutes of Health Stroke Scale, predictors of toxicology screens included Black race (adjusted odds ratio, 1.58 [95% CI, 1.02-2.45]), younger age (adjusted odds ratio, 0.70 [95% CI, 0.53-0.91], per 10 years), current smoking (adjusted odds ratio, 1.62 [95% CI, 1.06-2.46]), and treatment at an academic hospital (adjusted odds ratio, 1.80 [95% CI, 1.14-2.84]). After adding chart-reported substance use to the model, only chart-reported substance abuse and age were significant. CONCLUSIONS: In a population-based study of young adults with stroke, documented substance use increased over time, and documentation of substance use was higher among Black compared with White individuals. Further work is needed to confirm race-based disparities and trends in substance use given the potential for bias in screening and documentation. Findings suggest a need for more standardized toxicology screening.

Nonsteroidal Anti-Inflammatory Drugs: A Potential Pharmacological Treatment for Intracranial Aneurysm.

BACKGROUND: Saccular intracranial aneurysms (IAs) are outpouchings of the vessel wall of intracranial arteries. Rupture of IAs results in subarachnoid hemorrhage which is associated with high morbidity and mortality. Surgical interventions, such as clipping and coiling, have associated risks. Currently, there are no proven pharmacological treatments to prevent the growth or rupture of IAs. Infiltration of proinflammatory cytokines in response to increased wall sheer stress is a hallmark of IA. Nonsteroidal anti-inflammatory drugs (NSAIDs) are being investigated as potential therapeutic agents for reduction in growth and/or prevention of IA through inhibition of inflammatory pathways. SUMMARY: This review will discuss the role of NSAIDs in attenuating the inflammation that drives IA progression and rupture. There are two main subtypes of NSAIDs, nonselective COX and selective COX-2 inhibitors, both of which have merit in treating IA. Evidence will be presented which shows that NSAIDs inhibit several key inflammatory mediators involved in IA progression including nuclear factor-κB, tumor necrosis factor-α, and matrix metalloproteinases. In addition, the role of NSAIDs in limiting inflammatory cell adhesion to endothelial cells and attenuating endothelial cell senescence will be discussed. Key Messages: There is an abundance of basic science and preclinical data that support NSAIDs as a promising treatment for IA. Additionally, a combination treatment strategy of low-dose aspirin given concomitantly with a selective COX-2 inhibitor may result in a reduced side effect profile compared to aspirin or selective COX-2 inhibitor use alone. Several large clinical trials are currently planned to further investigate the efficacy of NSAIDs as an effective nonsurgical treatment for IAs.

Genetic Determinants of Cerebral Arterial Adaptation to Flow-loading.

BACKGROUND: In animal models, flow-loading is a necessary and sufficient hemodynamic factor to express the Cerebral Aneurysm (CA) phenotype. Using a rat model, this study characterizes the molecular events that comprise the cerebral arterial response to flow-loading and reveals their significance relating to the CA phenotype. OBJECTIVE: To characterize the molecular events that underlie expansive remodeling of cerebral arteries in two genetically distinct inbred rat strains with differential susceptibility to flow-dependent cerebrovascular pathology. METHODS: Thirty-two rats underwent bilateral common carotid artery ligation (BCL) (n=16) or Sham Surgery (SS) (n=16). Nineteen days later, vertebrobasilar arteries were harvested, histologically examined and analyzed for mRNA and protein expression. Flow-induced changes in histology, mRNA and protein expression were compared between BCL and SS rats. Differences between aneurysm-prone (Long Evans, LE) and resistant (Brown Norway, BN) strains were evaluated. RESULTS: Basilar Artery (BA) medial thickness/luminal diameter ratio was significantly reduced in BCL rats, without significant differences between LE (2.02 fold) and BN (1.94 fold) rats. BCL significantly altered BA expression of mRNA and protein but did not affect blood pressure. Eight genes showed similarly large flow-induced expression changes in LE and BN rats. Twenty-six flow responsive genes showed differences in flow-induced expression between LE and BN rats. The Cthrc1, Gsta3, Tgfb3, Ldha, Myo1d, Ermn, PTHrp, Rgs16 and TRCCP genes showed the strongest flow responsive expression, with the largest difference between LE and BN rats. CONCLUSIONS: Our study reveals specific molecular biological responses involved in flow-induced expansive remodeling of cerebral arteries that may influence differential expression of flowdependent cerebrovascular pathology.

Aggressiveness of care following intracerebral hemorrhage in women and men.

OBJECTIVE: To compare comorbidities and use of surgery and palliative care between men and women with intracerebral hemorrhage (ICH). METHODS: The Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study is a prospective, multicenter, case-control study of ICH risk factors and outcomes. We compared comorbidities, treatments, and use of do-not-resuscitate (DNR) orders in men vs women. Multivariate analysis was used to assess the likelihood of ICH surgery and palliative care after adjustment for variables that were p < 0.1 in univariate analyses and backward elimination to retain those that were significant (p < 0.05). RESULTS: Women were older on average (65.0 vs 59.9, p < 0.0001), and higher proportions of women had previous stroke (24.1% vs 19.3%, p = 0.002), had dementia (6.1% vs 3.4%, p = 0.0007), lived alone (23.1% vs 18.0%, p = 0.0005), and took anticoagulants (12.8% vs 10.1% p = 0.02), compared with men. Men had higher rates of alcohol and cocaine use. After adjusting for age, hematoma volume, and ICH location, there was no difference in rates of surgical treatment by sex (odds ratio [OR] 0.93 for men vs women, 95% confidence interval [CI] 0.68-1.28, p = 0.67), and there was no difference in DNR/comfort care decisions after adjustment for ICH score, prior stroke, and dementia (OR 0.96, CI 0.77-1.22, p = 0.76). CONCLUSIONS: After ICH, women do not receive less aggressive care than men after controlling for the substantial comorbidity differences. Future studies on sex bias should include the presence of comorbidities, prestroke disability, and other factors that may influence management.

Macrophage depletion lowers blood pressure and restores sympathetic nerve α2-adrenergic receptor function in mesenteric arteries of DOCA-salt hypertensive rats.

We tested the hypothesis that vascular macrophage infiltration and O2 (-) release impairs sympathetic nerve α2-adrenergic autoreceptor (α2AR) function in mesenteric arteries (MAs) of DOCA-salt hypertensive rats. Male rats were uninephrectomized or sham operated (sham). DOCA pellets were implanted subcutaneously in uninephrectomized rats who were provided high-salt drinking water or high-salt water with apocynin. Sham rats received tap water. Blood pressure was measured using radiotelemetry. Treatment of sham and DOCA-salt rats with liposome-encapsulated clodronate was used to deplete macrophages. After 3-5, 10-13, and 18-21 days of DOCA-salt treatment, MAs and peritoneal fluid were harvested from euthanized rats. Norepinephrine (NE) release from periarterial sympathetic nerves was measured in vitro using amperometry with microelectrodes. Macrophage infiltration into MAs as well as TNF-α and p22(phox) were measured using immunohistochemistry. Peritoneal macrophage activation was measured by flow cytometry. O2 (-) was measured using dihydroethidium staining. Hypertension developed over 28 days, and apocynin reduced blood pressure on days 18-21. O2 (-) and macrophage infiltration were greater in DOCA-salt MAs compared with sham MAs after day 10. Peritoneal macrophage activation occurred after day 10 in DOCA-salt rats. Macrophages expressing TNF-α and p22(phox) were localized near sympathetic nerves. Impaired α2AR function and increased NE release from sympathetic nerves occurred in MAs from DOCA-salt rats after day 18. Macrophage depletion reduced blood pressure and vascular O2 (-) while restoring α2AR function in DOCA-salt rats. Macrophage infiltration into the vascular adventitia contributes to increased blood pressure in DOCA-salt rats by releasing O2 (-), which disrupts α2AR function, causing enhanced NE release from sympathetic nerves.

Localization of NADPH oxidase in sympathetic and sensory ganglion neurons and perivascular nerve fibers.

Superoxide anion (O(2)(-*)) production was previously reported to be increased in celiac ganglia (CG) during DOCA-salt hypertension, possibly via activation of the reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase. This suggested a role for neuronal NADPH oxidase in autonomic neurovascular control. However, the expression and localization of NADPH oxidase in the peripheral neurons are not fully known. The purpose of this study was to examine the subcellular localization of NADPH oxidase in sympathetic and sensory ganglion neurons and perivascular nerve fibers. In rat CG, p22(phox) and neuropeptide Y (NPY) were colocalized in all neurons. P22(phox) was also localized to dorsal root ganglia (DRG) neurons that contain calcitonin gene related peptide (CGRP). In mesenteric arteries, p22(phox) and p47(phox) were colocalized with NPY or CGRP in perivascular nerve terminals. A similar pattern of nerve terminal staining of p22(phox) and p47(phox) was also found in cultured CG neurons and nerve growth factor (NGF)-differentiated PC12 cells. These data demonstrate a previously uncharacterized localization of NADPH oxidase in perivascular nerve fibers. The presence of a O(2)(-*)-generating enzyme in close vicinity to the sites of neurotransmitter handling in the nerve fibers suggests the possibility of novel redox-mediated mechanisms in peripheral neurovascular control.

Impaired purinergic neurotransmission to mesenteric arteries in deoxycorticosterone acetate-salt hypertensive rats.

Sympathetic nerves release norepinephrine and ATP onto mesenteric arteries. In deoxycorticosterone acetate (DOCA)-salt hypertensive rats, there is increased arterial sympathetic neurotransmission attributable, in part, to impaired prejunctional regulation of norepinephrine release. Prejunctional regulation purinergic transmission in hypertension is less well understood. We hypothesized that alpha(2)-adrenergic receptor dysfunction alters purinergic neurotransmission to arteries in DOCA-salt hypertensive rats. Mesenteric artery preparations were maintained in vitro, and intracellular electrophysiological methods were used to record excitatory junction potentials (EJPs) from smooth muscle cells. EJP amplitude was reduced in smooth muscle cells from DOCA-salt (4+/-1 mV) compared with control arteries (9+/-1 mV; P<0.05). When using short trains of stimulation (0.5 Hz; 5 pulses), the alpha(2)adrenergic receptor antagonist yohimbine (1 micromol/L) potentiated EJPs in control more than in DOCA-salt arteries (180+/-35% versus 86+/-7%; P<0.05). Norepinephrine (0.1 to 3.0 micromol/L), the alpha(2)adrenergic receptor agonist UK 14304 (0.001 to 0.100 micromol/L), the A(1) adenosine receptor agonist cyclopentyladensosine (0.3 to 100.0 micromol/L), and the N-type calcium channel blocker omega-conotoxin GVIA (0.0003 to 0.1000 micromol/L) decreased EJP amplitude equally well in control and DOCA-salt arteries. Trains of stimuli (10 Hz) depleted ATP stores more completely, and the latency to EJP recovery was longer in DOCA-salt compared with control arteries. These data indicate that there is reduced purinergic input to mesenteric arteries of DOCA-salt rats because of decreased ATP bioavailability in sympathetic nerves. These data highlight the potential importance of impaired purinergic regulation of arterial tone as a target for drug treatment of hypertension.