Clocks, Rhythms, Sex, and Hearts: How Disrupted Circadian Rhythms, Time-of-Day, and Sex Influence Cardiovascular Health

Cardiovascular diseases are the top cause of mortality in the United States, and ischemic heart disease accounts for 16% of all deaths around the world. Modifiable risk factors such as diet and exercise have often been primary targets in addressing these conditions. However, mounting evidence suggests that environmental factors that disrupt physiological rhythms might contribute to the development of these diseases, as well as contribute to increasing other risk factors that are typically associated with cardiovascular disease. Exposure to light at night, transmeridian travel, and social jetlag disrupt endogenous circadian rhythms, which, in turn, alter carefully orchestrated bodily functioning, and elevate the risk of disease and injury. Research into how disrupted circadian rhythms affect physiology and behavior has begun to reveal the intricacies of how seemingly innocuous environmental and social factors have dramatic consequences on mammalian physiology and behavior. Despite the new focus on the importance of circadian rhythms, and how disrupted circadian rhythms contribute to cardiovascular diseases, many questions in this field remain unanswered. Further, neither time-of-day nor sex as a biological variable have been consistently and thoroughly taken into account in previous studies of circadian rhythm disruption and cardiovascular disease. In this review, we will first discuss biological rhythms and the master temporal regulator that controls these rhythms, focusing on the cardiovascular system, its rhythms, and the pathology associated with its disruption, while emphasizing the importance of the time-of-day as a variable that directly affects outcomes in controlled studies, and how temporal data will inform clinical practice and influence personalized medicine. Finally, we will discuss evidence supporting the existence of sex differences in cardiovascular function and outcomes following an injury, and highlight the need for consistent inclusion of both sexes in studies that aim to understand cardiovascular function and improve cardiovascular health.

Call Characteristics of Patients Suspected of Transient Ischemic Attack (TIA) or Stroke During Out-of-Hours Service: A Comparison Between Men and Women

Background: In the Netherlands, a digital decision support system for telephone triage at out-of-hours services in primary care (OHS-PC) is used. Differences in help-seeking behavior between men and women when transient ischemic attack (TIA) or stroke is suspected could potentially affect telephone triage and allocation of urgency.

Aim: To assess patient and call characteristics and allocated urgencies between women and men who contacted OHS-PC with suspected TIA/stroke.

Methods: A cross-sectional study of 1,266 telephone triage recordings of subjects with suspected neurological symptoms calling the OHS-PC between 2014 and 2016. The allocated urgencies were derived from the electronic medical records of the OHS-PC and the final diagnosis from the patient's own general practitioner, including diagnoses based on hospital specialist letters.

Results: Five hundred forty-six men (mean age = 67.3 ± 17.1) and 720 women (mean age = 69.6 ± 19.5) were included. TIA/stroke was diagnosed in 294 men (54%) (mean age = 72.3 ± 13.6) and 366 women (51%) (mean age = 78.0 ± 13.8). In both genders, FAST (face-arm-speech test) symptoms were common in TIA/stroke (men 78%, women 82%) but also in no TIA/stroke (men 63%, women 62%). Men with TIA/stroke had shorter call durations than men without TIA/stroke (7.10 vs. 8.20 min, p = 0.001), whereas in women this difference was smaller and not significant (7.41 vs. 7.56 min, p = 0.41). Both genders were allocated high urgency in 75% of the final TIA/stroke cases.

Conclusion: Overall, patient and call characteristics are mostly comparable between men and women, and these only modestly assist in identifying TIA/stroke. There were no gender differences in allocated urgencies after telephone triage in patients with TIA/stroke.

Relationship between Nutritional Scales and Prognosis in Elderly Patients after Acute Ischemic Stroke: Comparison of Controlling Nutritional Status Score and Geriatric Nutritional Risk Index

BACKGROUND/AIMS

Undernutrition is common in patients after acute ischemic stroke (AIS) and predicts poor clinical outcomes. We assessed the relationship between undernutrition and prognosis after AIS.

METHODS

We retrospectively assessed consecutively hospitalized AIS patients aged ≥65 years. A poor prognosis for patients after AIS was defined as a modified Rankin Scale (mRS) score of ≥3 at discharge. Nutritional status was evaluated based on the degree and risk of undernutrition as determined by the Controlling Nutritional Status (UND-CONUT) and Geriatric Nutritional Risk Index (UNR-GNRI) scores.

RESULTS

Among 218 patients (male, 62.8%; median age, 77 years), 81 had a poor prognosis. A significant correlation was found between UND-CONUT and UNR-GNRI scores (p < 0.001, r = 0.433). Patients with a poor prognosis showed significant undernutrition based on UND-CONUT (p = 0.003) but not on UNR-GNRI (p = 0.218). Patients with undernutrition based on UND-CONUT showed poor outcomes: higher mRS scores at discharge, higher percentages of mRS scores of ≥2 and ≥3, and more complications associated with pneumonia. No significant differences were seen between cases with and without undernutrition risk based on UNR-GNRI.

CONCLUSION

UND-CONUT appeared to be more useful than UNR-GNRI for predicting the prognosis of elderly patients with AIS at discharge.

Intracranial VCAM1 at time of mechanical thrombectomy predicts ischemic stroke severity

Background

Emergent large vessel occlusion (ELVO) strokes are devastating ischemic vascular events for which novel treatment options are needed. Using vascular cell adhesion molecule 1 (VCAM1) as a prototype, the objective of this study was to identify proteomic biomarkers and network signaling functions that are potential therapeutic targets for adjuvant treatment for mechanical thrombectomy.

Methods

The blood and clot thrombectomy and collaboration (BACTRAC) study is a continually enrolling tissue bank and registry from stroke patients undergoing mechanical thrombectomy. Plasma proteins from intracranial (distal to clot) and systemic arterial blood (carotid) were analyzed by Olink Proteomics for N=42 subjects. Statistical analysis of plasma proteomics used independent sample t tests, correlations, linear regression, and robust regression models to determine network signaling and predictors of clinical outcomes. Data and network analyses were performed using IBM SPSS Statistics, SAS v 9.4, and STRING V11.

Results

Increased systemic (p<0.001) and intracranial (p=0.013) levels of VCAM1 were associated with the presence of hypertension. Intracranial VCAM1 was positively correlated to both infarct volume (p=0.032; r=0.34) and edema volume (p=0.026; r=0.35). The %∆ in NIHSS from admittance to discharge was found to be significantly correlated to both systemic (p=0.013; r = −0.409) and intracranial (p=0.011; r = −0.421) VCAM1 levels indicating elevated levels of systemic and intracranial VCAM1 are associated with reduced improvement of stroke severity based on NIHSS from admittance to discharge. STRING-generated analyses identified biologic functional descriptions as well as function-associated proteins from the predictive models of infarct and edema volume.

Conclusions

The current study provides novel data on systemic and intracranial VCAM1 in relation to stroke comorbidities, stroke severity, functional outcomes, and the role VCAM1 plays in complex protein-protein signaling pathways. These data will allow future studies to develop predictive biomarkers and proteomic targets for drug development to improve our ability to treat a devastating pathology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02157-4.

Sex Differences in Stroke Hospitalization Incidence, 30-Day Mortality, and Readmission in a Regional Medical Center in the Southwestern United States

OBJECTIVES

This study explores sex differences in ischemic stroke hospitalization incidence, 30-day mortality, and 30-day readmission in a southwestern US medical center.

METHODS

Ischemic stroke admissions in a regional medical center in the southwestern United States were obtained for a 6.5-year time frame (N = 1968). Logistic regression models examine the adjusted effects of sex on 30-day mortality and 30-day readmission outcomes among individuals hospitalized for ischemic stroke.

RESULTS

Findings confirm that although women experience higher mortality than men (9.1% vs 6.7%), the sex disparity in mortality is explained by the age distribution of strokes. Women experience far more strokes and deaths because of stroke at older ages. No differences in principal procedure or 30-day readmission emerged.

CONCLUSIONS

Men experienced higher stroke hospitalization incidence, although women exhibited higher 30-day mortality. Age composition explained sex differences in mortality, but higher male stroke hospitalization incidence represents a larger public health issue that suggests the need for behavioral change at the population level. No meaningful sex differences emerged in treatment, mortality, or readmission.

Simultaneous nicotine and oral contraceptive exposure alters brain energy metabolism and exacerbates ischemic stroke injury in female rats

Smoking-derived nicotine (N) and oral contraceptives (OC) synergistically exacerbate ischemic brain damage in the females and underlying mechanisms remain elusive. Our published study showed that N toxicity is exacerbated by OC via altered mitochondrial function owing to a defect in the activity of cytochrome c oxidase. Here, we investigated the global metabolomic profile of brains of adolescent female Sprague-Dawley rats exposed to N ± OC. Rats were randomly exposed to saline or N + /-OC for 16-21 days followed by random allocation into two cohorts. One cohort underwent transient middle cerebral artery occlusion and histopathology was performed 30 days later. From the second cohort, cortical tissues were collected for an unbiased global metabolomic profile. Pathway enrichment analysis showed significant decrease in glucose, glucose 6-phosphate and fructose-6-phosphate, along with a significant increase in pyruvate in the N + /-OC exposed groups when compared to saline (p < 0.05), suggesting alterations in the glycolytic pathway which were confirmed by Western blot analyses of glycolytic enzymes. Infarct volume quantification showed a significant increase following N alone or N + OC as compared to saline control. Because glucose metabolism is critical for brain physiology, altered glycolysis deteriorates neural function, thus exacerbating ischemic brain damage.

Targeting the Autonomic Nervous System for Risk Stratification, Outcome Prediction and Neuromodulation in Ischemic Stroke

Ischemic stroke is a worldwide major cause of mortality and disability and has high costs in terms of health-related quality of life and expectancy as well as of social healthcare resources. In recent years, starting from the bidirectional relationship between autonomic nervous system (ANS) dysfunction and acute ischemic stroke (AIS), researchers have identified prognostic factors for risk stratification, prognosis of mid-term outcomes and response to recanalization therapy. In particular, the evaluation of the ANS function through the analysis of heart rate variability (HRV) appears to be a promising non-invasive and reliable tool for the management of patients with AIS. Furthermore, preclinical molecular studies on the pathophysiological mechanisms underlying the onset and progression of stroke damage have shown an extensive overlap with the activity of the vagus nerve. Evidence from the application of vagus nerve stimulation (VNS) on animal models of AIS and on patients with chronic ischemic stroke has highlighted the surprising therapeutic possibilities of neuromodulation. Preclinical molecular studies highlighted that the neuroprotective action of VNS results from anti-inflammatory, antioxidant and antiapoptotic mechanisms mediated by α7 nicotinic acetylcholine receptor. Given the proven safety of non-invasive VNS in the subacute phase, the ease of its use and its possible beneficial effect in hemorrhagic stroke as well, human studies with transcutaneous VNS should be less challenging than protocols that involve invasive VNS and could be the proof of concept that neuromodulation represents the very first therapeutic approach in the ultra-early management of stroke.

Women With Osteoarthritis Are at Increased Risk of Ischemic Stroke: A Population-Based Cohort Study

Background

Osteoarthritis (OA) is more prevalent in women with age. Comorbidities are prevalent in OA patients. In this study, we conducted a follow-up study to evaluate whether women with OA are at an increased risk of ischemic stroke using insurance claims data of Taiwan.

Methods

We identified 13,520 women with OA aged 20–99 newly diagnosed in 2000–2006 and 27,033 women without OA for comparison, frequency matched by age and diagnosis date. Women with baseline history of hypertension and other disorders associated with stroke were excluded for this study. Incident ischemic stroke was assessed by the end of 2013. A nested case-control analysis was used to identify factors associated with the stroke in the OA cohort.

Results

The incidence rate of ischemic stroke in the OA cohort was 1.5-fold greater than that in comparisons (1.93 versus 1.26 per 1,000 person-years), with an adjusted hazard ratio of 1.34 (95% confidence interval [CI], 1.09–1.66). The nested case-control analysis showed that stroke cases were twice as likely to develop hypertension during the follow-up period than controls without stroke. The ischemic stroke risk was significantly associated with hypertension (odds ratio [OR] 1.84; 95% CI, 1.37–2.46) and atrial fibrillation (OR 2.25; 95% CI, 1.24–4.09). Ischemic stroke was not associated with the use of non-steroidal anti-inflammatory drugs or aspirin.

Conclusion

Women with OA are at an elevated risk of ischemic stroke. A close monitoring of hypertension, atrial fibrillation, and other stroke related comorbidities is required for stroke prevention for OA patients.

Increased P450 aromatase levels in post-menopausal women after acute ischemic stroke

Background

Sex differences in stroke have been attributed to the neuroprotective effects of estrogen, yet most clinical trials of estrogen supplementation for stroke prevention have failed. The contribution of sex hormones to stroke outcome remains a subject of debate. Aromatization of testosterone to estradiol in neural tissue leads to sexual differentiation. Emerging data suggests aromatase activity increases in response to brain injury, and increased aromatase expression is seen in the ischemic penumbra in animal models. The objective of this study was to examine the levels of endogenous sex steroids after acute ischemic stroke and determine if levels of sex steroids were associated with acute stroke outcomes.

Methods

Peripheral blood from ischemic stroke patients and controls was collected under an approved IRB within 24 h of symptom onset. 17β-estradiol, testosterone, and aromatase levels were measured in the serum of both men and women using ELISA. Hormone levels were compared in men vs. women in stroke and control groups and correlated with outcomes (NIHSS and change in the modified Rankin Scale (mRS), defined as the difference of premorbid and discharge mRS) using multivariate regression.

Results

We found no significant difference in estradiol levels 24 h after stroke in men (p = 0.86) or women (p = 0.10). In men, testosterone significantly decreased after stroke as compared with controls (1.83 ± 0.12 vs. 2.86 ± 0.65, p = 0.01). Aromatase levels were significantly increased in women after stroke as compared with controls (2.27 ± 0.22 vs. 0.97 ± 0.22, p = 0.002), but not in men (p = 0.84). Estradiol levels positively correlated with change in mRS in both women (r = 0.38, p = 0.02) and men (r = 0.3, p = 0.04).

Conclusions

Estradiol levels correlated with functional outcomes (change in mRS) in both men and women, at least in the acute phase (24 h) of stroke. However, no significant difference in estradiol levels is seen 24 h post-stroke in men or women. Testosterone levels decrease at 24 h after stroke in men. As seen in animal models, aromatase levels increase after acute ischemic stroke, but this was only true for women. These indicate an active aromatization process in post-menopausal women after acute ischemic stroke.

Deletion of muscarinic acetylcholine receptor 3 in microglia impacts brain ischemic injury

Microglia are the immune cells of the brain and become activated during any type of brain injury. In the middle cerebral artery occlusion (MCAo) model, a mouse model for ischemic stroke, we have previously shown that microglia and invaded monocytes upregulate the expression of the muscarinic acetylcholine receptor 3 (M3R) in the ischemic lesion. Here we tested whether this upregulation has an impact on the pathogenesis of MCAo. We depleted the m3R receptor in microglia, but not in circulating monocytes by giving tamoxifen to CX3CR1-CreERT^+/+M3R^flox/flox (M3RKO^mi) animals 3 weeks prior to MCAo. We found that M3RKO^mi male mice had bigger lesions, more pronounced motor deficits after one week and cognitive deficits after about one month compared to control males. The density of Iba1⁺ cells was lower in the lesions of M3RKO male mice in the early, but not in the late disease phase. In females, these differences were not significant. By giving tamoxifen 1 week prior to MCAo, we depleted m3R in microglia and in circulating monocytes (M3RKO^mi/mo). Male M3RKO^mi/mo did not differ in lesion size, but had a lower survival rate, showed motor deficits and a reduced accumulation of Iba1⁺ positive cells into the lesion site. In conclusion, our data suggest that the upregulation of m3R in microglia and monocytes in stroke has a beneficial effect on the clinical outcome in male mice.

Comparison between Ischemic and Hemorrhagic Strokes in Functional Outcome at Discharge from an Intensive Rehabilitation Hospital

Comparison studies on recovery outcomes in ischemic (IS) and hemorrhagic strokes (HS) have yielded mixed results. In this retrospective observational study of consecutive IS and HS patients, we aimed at evaluating functional outcomes at discharge from an intensive rehabilitation hospital, comparing IS vs. HS, analyzing possible predictors. Modified Rankin Scale (mRS) at discharge was the main outcome. Out of the 229 patients included (mean age 72.9 ± 13.9 years, 48% males), 81 had HS (35%). Compared with IS (n = 148), HS patients were significantly younger (75 ± 12.5 vs. 68.8 ± 15.4 years, p = 0.002), required longer hospitalizations both in acute (23.9 ± 36.7 vs. 35.2 ± 29.9 days, p = 0.019) and rehabilitation hospitals (41.5 ± 31.8 vs. 77.2 ± 51.6 days, p = 0.001), and had more severe initial clinical deficit (mean number of neurological impairments: 2.0 ± 1.1 vs. 2.6 ± 1.4, p = 0.001) and mRS scores at admission (p = 0.046). At discharge, functional status change, expressed as mRS, was not significantly different between IS and HS (F = 0.01, p = 0.902), nor was the discharge destination (p = 0.428). Age and clinical severity were predictors of functional outcome in both stroke types. On admission in an intensive rehabilitation hospital, HS patients presented a worse functional and clinical status compared to IS. Despite this initial gap, the two stroke types showed an overlapped trajectory of functional recovery, with age and initial stroke severity as the main prognostic factors.

Sex disparity in long-term stroke recurrence and mortality in a rural population in the United States

BACKGROUND

Several studies suggest women may be disproportionately affected by poorer stroke outcomes than men. This study aims to investigate whether women have a higher risk of all-cause mortality and recurrence after an ischemic stroke than men in a rural population in central Pennsylvania, United States.

METHODS

We analyzed consecutive ischemic stroke patients captured in the Geisinger NeuroScience Ischemic Stroke research database from 2004 to 2019. Kaplan-Meier (KM) estimator curves stratified by gender and age were used to plot survival probabilities and Cox Proportional Hazards Ratios were used to analyze outcomes of all-cause mortality and the composite outcome of ischemic stroke recurrence or death. Fine-Gray Competing Risk models were used for the outcome of recurrent ischemic stroke, with death as the competing risk. Two models were generated; Model 1 was adjusted by data-driven associated health factors, and Model 2 was adjusted by traditional vascular risk factors.

RESULTS

Among 8900 adult ischemic stroke patients [median age of 71.6 (interquartile range: 61.1-81.2) years and 48% women], women had a higher crude all-cause mortality. The KM curves demonstrated a 63.3% survival in women compared with a 65.7% survival in men (p = 0.003) at 5 years; however, the survival difference was not present after controlling for covariates, including age, atrial fibrillation or flutter, myocardial infarction, diabetes mellitus, dyslipidemia, heart failure, chronic lung diseases, rheumatic disease, chronic kidney disease, neoplasm, peripheral vascular disease, past ischemic stroke, past hemorrhagic stroke, and depression. There was no adjusted or unadjusted sex difference in terms of recurrent ischemic stroke or composite outcome.

CONCLUSION

Sex was not an independent risk factor for all-cause mortality and ischemic stroke recurrence in the rural population in central Pennsylvania.

Pathophysiology and Treatment of Stroke: Present Status and Future Perspectives

Stroke is the second leading cause of death and a major contributor to disability worldwide. The prevalence of stroke is highest in developing countries, with ischemic stroke being the most common type. Considerable progress has been made in our understanding of the pathophysiology of stroke and the underlying mechanisms leading to ischemic insult. Stroke therapy primarily focuses on restoring blood flow to the brain and treating stroke-induced neurological damage. Lack of success in recent clinical trials has led to significant refinement of animal models, focus-driven study design and use of new technologies in stroke research. Simultaneously, despite progress in stroke management, post-stroke care exerts a substantial impact on families, the healthcare system and the economy. Improvements in pre-clinical and clinical care are likely to underpin successful stroke treatment, recovery, rehabilitation and prevention. In this review, we focus on the pathophysiology of stroke, major advances in the identification of therapeutic targets and recent trends in stroke research.

Diagnosis of Transient Ischemic Attack: Sex-Specific Differences From a Retrospective Cohort Study

BACKGROUND AND PURPOSE

Research suggests that women and men may present with different transient ischemic attack (TIA) and stroke symptoms. We aimed to explore symptoms and features associated with a definite TIA/stroke diagnosis and whether those associations differed by sex.

METHODS

We completed a retrospective cohort study of patients referred to The Ottawa Hospital Stroke Prevention Clinic in 2015. Exploratory multinomial logistic regression was used to evaluate candidate variables associated with diagnosis and patient sex. Backwards elimination of the interaction terms with a significance level for staying in the model of 0.25 was used to arrive at a more parsimonious model.

RESULTS

Based on 1770 complete patient records, sex-specific differences were noted in TIA/stroke diagnosis based on features such as duration of event, suddenness of symptom onset, unilateral sensory loss, and pain.

CONCLUSIONS

This preliminary work identified sex-specific differences in the final diagnosis of TIA/stroke based on common presenting symptoms/features. More research is needed to understand if there are biases or sex-based differences in TIA/stroke manifestations and diagnosis.

Sex differences of ischemic stroke in young adults-A single-center Chinese cohort study

BACKGROUND AND OBJECTIVE

Stroke at a young age is a societal challenge with a rising incidence. Our aim was to investigate sex differences in risk factors, etiology, and diagnostic process of ischemic stroke in Chinese young adults.

METHODS

We retrospectively recruited 411 consecutive patients with first-ever ischemic stroke who were 18 to 50 years of age (mean age, 38.2 ± 8.1 years, women 31.4%), admitted to Peking Union Medical College Hospital from 2007 to 2018. Sex differences in demographics, risk factors, etiology, and diagnostic testing were analyzed.

RESULTS

Females were significantly younger than males (36.9 versus 38.7 years, P<0.05). Hypertension (43.0%), smoking (41.1%), hyperlipidemia (37.2%), and hyperhomocysteinemia (27.9%) were common risk factors, statistically higher among males than females (P<0.05). Stroke etiology showed a significant sex difference that large-artery atherosclerosis and small-vessel diseases were more common among males than females (48.6% versus 19.4%, P<0.001; 9.9% versus 3.1%, P<0.05, respectively). Stroke of other determined etiology was more common among females (50.4% versus 19.1%, P<0.001). Relevant abnormality rates were higher among females on screening for autoimmune diseases and thrombophilia (23.3% versus 11.1%, P<0.05 and 50.0% versus 16.7%, P<0.001, respectively).

CONCLUSIONS

A high rate of the traditional stroke risk factors and etiological subtype of large artery atherosclerosis in males were found, as well as prominent sex differences in relevant diagnostic testing abnormality rates, providing useful information for developing sex-specific strategies in stroke evaluation and prevention in young adults.

Sex Differences in Prehospital Delay in Patients With Acute Stroke: A Systematic Review

BACKGROUND

In 2009, the window from symptom onset to administration of tissue plasminogen activator for acute ischemic stroke was extended from 3 to 4.5 hours. Yet no systematic review has addressed prehospital delay by sex for stroke symptoms since this change.

PURPOSE

We aimed to (1) compare prehospital delay times-the time from symptom onset to hospital arrival-between women and men with acute stroke or transient ischemic attack and (2) summarize factors influencing prehospital delay by sex.

METHODS

The CINAHL, MEDLINE, PubMed, Scopus, and PsycINFO databases were searched using PRISMA guidelines. Inclusion criteria were as follows: (1) quantitative research articles published between May 2008 and April 2019, (2) investigation of prehospital delay among women and men 15 years or older who were given a diagnosis of acute stroke or transient ischemic attack, and (3) English-language publications. The Crowe Critical Appraisal Tool was used to evaluate the quality of studies.

RESULTS

Fifteen publications (n = 162 856) met inclusion criteria. Most studies (n = 11) showed no sex differences in prehospital delay. Four studies from Asian-Pacific countries and the United States showed that women had significantly longer prehospital delay compared with men. Older age, minority race/ethnicity (black and Mexican American), and underuse of emergency medical services were associated with prolonged prehospital delay in women.

CONCLUSIONS

Most study authors found no differences in prehospital delay between women and men; however, women delayed longer in some Asian-Pacific and American studies. Findings of sex differences were inconclusive.

Sex differences in IV thrombolysis treatment for acute ischemic stroke

Objective

A prior meta-analysis of reports published between 2000 and 2008 found that women were 30% less likely to receive IV recombinant tissue plasminogen activator (rtPA) treatment for stroke than men; we updated this meta-analysis to determine if this sex difference persisted.

Methods

We identified studies that reported sex-specific IV rtPA treatment rates for acute ischemic stroke published between 2008 and 2018. Eligible studies included representative populations of patients with ischemic stroke from hospital-based, registry-based, or administrative data. Random effects odds ratios (ORs) were generated to quantify sex differences.

Results

Twenty-four eligible studies were identified during this 10-year period. The summary unadjusted OR based on 17 studies with data on all ischemic stroke patients was 0.87 (95% confidence interval [CI], 0.82–0.93), indicating that women had 13% lower odds of receiving IV rtPA treatment than men. However, substantial between-study variability existed. Lower treatment odds in women were also observed in 7 studies that provided data on the subgroup of patients eligible for IV rtPA treatment, although the summary OR of 0.95 (95% CI, 0.88–1.02) was not statistically significant. Examination of time trends across 33 studies published between 2000 and 2018 found evidence that the sex difference had narrowed in more recent years.

Conclusions

Although there is considerable variability in the findings of individual studies, pooled data from recent studies show that women with acute stroke are less likely to be treated with IV thrombolysis compared with men. However, the size of this difference has narrowed compared to studies published before 2008.

Sex differences in the response to oxidative and proteolytic stress

Sex differences in diseases involving oxidative and proteolytic stress are common, including greater ischemic heart disease, Parkinson disease and stroke in men, and greater Alzheimer disease in women. Sex differences are also observed in stress response of cells and tissues, where female cells are generally more resistant to heat and oxidative stress-induced cell death. Studies implicate beneficial effects of estrogen, as well as cell-autonomous effects including superior mitochondrial function and increased expression of stress response genes in female cells relative to male cells. The p53 and forkhead box (FOX)-family genes, heat shock proteins (HSPs), and the apoptosis and autophagy pathways appear particularly important in mediating sex differences in stress response.

Pregnancy, postpartum and parity: Resilience and vulnerability in brain health and disease

Risk and resilience in brain health and disease can be influenced by a variety of factors. While there is a growing appreciation to consider sex as one of these factors, far less attention has been paid to sex-specific variables that may differentially impact females such as pregnancy and reproductive history. In this review, we focus on nervous system disorders which show a female bias and for which there is data from basic research and clinical studies pointing to modification in disease risk and progression during pregnancy, postpartum and/or as a result of parity: multiple sclerosis (MS), depression, stroke, and Alzheimer's disease (AD). In doing so, we join others (Shors, 2016; Galea et al., 2018a) in aiming to illustrate the importance of looking beyond sex in neuroscience research.

Sex differences in the structure and function of rat middle cerebral arteries

Epidemiological studies demonstrate that there are sex differences in the incidence, prevalence, and outcomes of cerebrovascular disease (CVD). The present study compared the structure and composition of the middle cerebral artery (MCA), neurovascular coupling, and cerebrovascular function and cognition in young Sprague-Dawley (SD) rats. Wall thickness and the inner diameter of the MCA were smaller in females than males. Female MCA exhibited less vascular smooth muscle cells (VSMCs), diminished contractile capability, and more collagen in the media, and a thicker internal elastic lamina with fewer fenestrae compared with males. Female MCA had elevated myogenic tone, lower distensibility, and higher wall stress. The stress/strain curves shifted to the left in female vessels compared with males. The MCA of females failed to constrict compared with a decrease of 15.5 ± 1.9% in males when perfusion pressure was increased from 40 to 180 mmHg. Cerebral blood flow (CBF) rose by 57.4 ± 4.4 and 30.1 ± 3.1% in females and males, respectively, when perfusion pressure increased from 100 to 180 mmHg. The removal of endothelia did not alter the myogenic response in both sexes. Functional hyperemia responses to whisker-barrel stimulation and cognition examined with an eight-arm water maze were similar in both sexes. These results demonstrate that there are intrinsic structural differences in the MCA between sexes, which are associated with diminished myogenic response and CBF autoregulation in females. The structural differences do not alter neurovascular coupling and cognition at a young age; however, they might play a role in the development of CVD after menopause.

NEW & NOTEWORTHY Using perfusion fixation of the middle cerebral artery (MCA) in calcium-free solution at physiological pressure and systematically randomly sampling the sections prepared from the same M2 segments of MCA, we found that there are structural differences that are associated with altered cerebral blood flow (CBF) autoregulation but not neurovascular coupling and cognition in young, healthy Sprague-Dawley (SD) rats. Understanding the intrinsic differences in cerebrovascular structure and function in males and females is essential to develop new pharmaceutical treatments for cerebrovascular disease (CVD).

Endothelium-Targeted Deletion of microRNA-15a/16-1 Promotes Poststroke Angiogenesis and Improves Long-Term Neurological Recovery

RATIONALE

Angiogenesis promotes neurological recovery after stroke and is associated with longer survival of stroke patients. Cerebral angiogenesis is tightly controlled by certain microRNAs (miRs), such as the miR-15a/16-1 cluster, among others. However, the function of the miR-15a/16-1 cluster in endothelium on postischemic cerebral angiogenesis is not known.

OBJECTIVE

To investigate the functional significance and molecular mechanism of endothelial miR-15a/16-1 cluster on angiogenesis in the ischemic brain.

METHODS AND RESULTS

Endothelial cell-selective miR-15a/16-1 conditional knockout (EC-miR-15a/16-1 cKO) mice and wild-type littermate controls were subjected to 1 hour middle cerebral artery occlusion followed by 28-day reperfusion. Deletion of miR-15a/16-1 cluster in endothelium attenuates post-stroke brain infarction and atrophy and improves the long-term sensorimotor and cognitive recovery against ischemic stroke. Endothelium-targeted deletion of the miR-15a/16-1 cluster also enhances post-stroke angiogenesis by promoting vascular remodeling and stimulating the generation of newly formed functional vessels, and increases the ipsilateral cerebral blood flow. Endothelial cell-selective deletion of the miR-15a/16-1 cluster up-regulated the protein expression of pro-angiogenic factors VEGFA (vascular endothelial growth factor), FGF2 (fibroblast growth factor 2), and their receptors VEGFR2 (vascular endothelial growth factor receptor 2) and FGFR1 (fibroblast growth factor receptor 1) after ischemic stroke. Consistently, lentiviral knockdown of the miR-15a/16-1 cluster in primary mouse or human brain microvascular endothelial cell cultures enhanced in vitro angiogenesis and up-regulated pro-angiogenic proteins expression after oxygen-glucose deprivation, whereas lentiviral overexpression of the miR-15a/16-1 cluster suppressed in vitro angiogenesis and down-regulated pro-angiogenic proteins expression. Mechanistically, miR-15a/16-1 translationally represses pro-angiogenic factors VEGFA, FGF2, and their receptors VEGFR2 and FGFR1, respectively, by directly binding to the complementary sequences within 3'-untranslated regions of those messenger RNAs.

CONCLUSIONS

Endothelial miR-15a/16-1 cluster is a negative regulator for postischemic cerebral angiogenesis and long-term neurological recovery. Inhibition of miR-15a/16-1 function in cerebrovascular endothelium may be a legitimate therapeutic approach for stroke recovery.

Is There a Link Between Carotid Atherosclerosis and Idiopathic Overactive Bladder Among Women with Metabolic Syndrome?

Purpose

To evaluate the association between increased intima-media thickness (IMT) and atherosclerotic carotid plaque (CP) with idiopathic overactive bladder syndrome (OAB) in women with metabolic syndrome (MetS).

Methods

This is a cross-sectional study, which included consecutive women aged 40–75 years with MetS, seeking medical assistance at a reference center between April and December 2016. OAB-V8 questionnaire was used to estimate the prevalence of OAB symptoms, which were defined by a score ≥8 points. All patients underwent bilateral carotid artery ultrasound to assess IMT and CP. Atherosclerosis was defined by the identification of CP during ultrasound, which was diagnosed according to the Mannheim carotid intima-media thickness and plaque consensus.

Results

Forty-five women were prospectively included. Mean age was 60±9.3 years (range 40–75 ys). Eighteen (40%) patients were diagnosed with OAB. IMT in the general population was 0.72 mm (SD = 0.20). Overall prevalence of atherosclerosis, defined by the presence of the carotid artery plaque, was 51%. OAB prevalence among women with atherosclerosis was higher than in those without atherosclerosis (56.52% versus 22.73%), with a prevalence ratio of 2.49 (p=0.04). Additionally, OAB was associated with degree of carotid stenosis (p = 0.029).

Conclusion

In this cohort of female patients with MetS, there was an association between carotid atherosclerosis and OAB. Identification of carotid ultrasound abnormalities may lead to refined treatment decision-making among OAB patients.

Differential Impact of Risk Factors on Stroke Occurrence Among Men Versus Women in West Africa

Background and Purpose- The interplay between sex and the dominant risk factors for stroke occurrence in sub-Saharan Africa has not been clearly delineated. We compared the effect sizes of risk factors of stroke by sex among West Africans. Methods- SIREN study (Stroke Investigative Research and Educational Networks) is a case-control study conducted at 15 sites in Ghana and Nigeria. Cases were adults aged >18 years with computerized tomography/magnetic resonance imaging confirmed stroke, and controls were age- and sex-matched stroke-free adults. Comprehensive evaluation for vascular, lifestyle, and psychosocial factors was performed using validated tools. We used conditional logistic regression to estimate odds ratios and reported risk factor specific and composite population attributable risks with 95% CIs. Results- Of the 2118 stroke cases, 1193 (56.3%) were males. The mean±SD age of males was 58.1±13.2 versus 60.15±14.53 years among females. Shared modifiable risk factors for stroke with adjusted odds ratios (95% CI) among females versus males, respectively, were hypertension [29.95 (12.49-71.77) versus 16.1 0(9.19-28.19)], dyslipidemia [2.08 (1.42-3.06) versus 1.83 (1.29-2.59)], diabetes mellitus [3.18 (2.11-4.78) versus 2.19 (1.53-3.15)], stress [2.34 (1.48-3.67) versus 1.61 (1.07-2.43)], and low consumption of green leafy vegetables [2.92 (1.89-4.50) versus 2.00 (1.33-3.00)]. However, salt intake and income were significantly different between males and females. Six modifiable factors had a combined population attributable risk of 99.1% (98.3%-99.6%) among females with 9 factors accounting for 97.2% (94.9%-98.7%) among males. Hemorrhagic stroke was more common among males (36.0%) than among females (27.6%), but stroke was less severe among males than females. Conclusions- Overall, risk factors for stroke occurrence are commonly shared by both sexes in West Africa favoring concerted interventions for stroke prevention in the region.

Sex differences in stroke

Sex disparities within the field of stroke, including subarachnoid hemorrhages (SAHs), have been in focus during the last 2 decades. It is clear that stroke incidence is higher in men, and also that men have their first stroke earlier than women. On the other hand, women have more severe strokes, mainly because cardioembolic strokes are more common in women. This leads to higher case fatality and worse functional outcome in women. It has often been pointed out that women more often have nontraditional stroke symptoms, and therefore may seek medical help later. After discharge from the hospital, female stroke survivors live alone in many cases and are dependent on external care. Therefore, these women frequently rate their quality of life (QoL) lower than men do. Female spouses more often provide help to their male stroke survivors than the reverse, and they accept a heavier burden. These caregivers are at high risk for depression, low QoL, and low psychologic wellbeing. SAH is a special form of stroke, often caused by a ruptured aneurysm. It is about 20% more common in women. The case fatality is high, but does not differ between the sexes.

Interactions of Aromatase and Seladin-1: A Neurosteroidogenic and Gender Perspective

Aromatase and seladin-1 are enzymes that have major roles in estrogen synthesis and are important in both brain physiology and pathology. Aromatase is the key enzyme that catalyzes estrogen biosynthesis from androgen precursors and regulates the brain’s neurosteroidogenic activity. Seladin-1 is the enzyme that catalyzes the last step in the biosynthesis of cholesterol, the precursor of all hormones, from desmosterol. Studies indicated that seladin-1 is a downstream mediator of the neuroprotective activity of estrogen. Recently, we also showed that there is an interaction between aromatase and seladin-1 in the brain. Therefore, the expression of local brain aromatase and seladin-1 is important, as they produce neuroactive steroids in the brain for the protection of neuronal damage. Increasing steroid biosynthesis specifically in the central nervous system (CNS) without affecting peripheral hormone levels may be possible by manipulating brain-specific promoters of steroidogenic enzymes. This review emphasizes that local estrogen, rather than plasma estrogen, may be responsible for estrogens’ protective effects in the brain. Therefore, the roles of aromatase and seladin-1 and their interactions in neurodegenerative events such as Alzheimer’s disease (AD), ischemia/reperfusion injury (stroke), and epilepsy are also discussed in this review.

Gender differences in post-stroke depression: A longitudinal analysis of prevalence, persistence and predictive value of known risk factors

Post-stroke depression (PSD) is the most frequent psychiatric condition after stroke with a prevalence of approximately 33%. In the general population, depression is consistently reported to be more frequent in women than in men. Evidence about gender differences in PSD remains inconclusive and it is unknown if established risk factors exert gender-specific influence. The authors examined gender differences in PSD prevalence, persistence and influence of established risk factors using χ ²- and Welch's t-tests and continuous-time structural equation modelling (CT-SEM). Patients (N = 301) from the longitudinal Berlin-PSD-study were assessed six weeks (baseline), and up to four times during the first 2.5 years post-stroke using DSM-5 depression criteria and the Geriatric Depression Scale (GDS). Established risk factors were assessed at baseline. Women showed higher PSD prevalence and severity at baseline (p < .01) but not thereafter (p ≥ .43). CT-SEM analysis revealed that known risk factors predicted depression, yet predictive value and persistence did not differ between genders. Our results showed that established PSD risk factors influence both genders to a similar extent and that in contrast to depression in the general population, gender differences in PSD prevalence and severity disappeared within six months post-stroke. Thus, for reasons yet to be deciphered, gender differences in PSD appear to be time-dependent after stroke.

Simultaneous alterations of oligodendrocyte-specific CNP, astrocyte-specific AQP4 and neuronal NF-L demarcate ischemic tissue after experimental stroke in mice

Ischemic stroke not only affects neurons, but also glial and vascular elements. The development of novel neuroprotective strategies thus requires an improved pathophysiological understanding of ischemia-affected cell types that comprise the 'neurovascular unit' (NVU). To explore spatiotemporal alterations of oligodendrocytes, astrocytes and neurons after experimental ischemic stroke, we applied a permanent middle cerebral artery occlusion model in mice for 4 and 24 h. Using fluorescence microscopy, the oligodendrocyte marker 2',3'-cyclic nucleotide phosphodiesterase (CNP), the neuronal neurofilament light chain (NF-L) and the astroglial aquaporin-4 (AQP4) were analyzed in regional relation to one another. Immunofluorescence intensities of CNP and NF-L were simultaneously increased in the ischemic neocortex and striatum. AQP4 immunoreactivity was decreased in the ischemic striatum, which represents the initial and potentially strongest affected site of infarction. The more distant ischemic neocortex and infarct border zones exhibited areas with alternately increased or decreased AQP4 immunoreactivity, leading to an increase of fluorescence intensity in total. Further, deformed CNP-immunopositive processes were found around axonal spheroids, indicating a combined affection of oligodendrocytes and neurons due to ischemia. Importantly, altered AQP4 immunosignals were not limited to the ischemic core, but were also detectable in penumbral areas. This applies for CNP and NF-L also, since altered immunosignals of all three markers coincided regionally at both time points. In conclusion, the present study provides evidence for a simultaneous affection of oligodendrocytes, astrocytes and neurons after experimental focal cerebral ischemia. Consequently, CNP, AQP4 and NF-L immunofluorescence alterations can be utilized to identify ischemia-affected tissue. The simultaneity of the described alterations further strengthens the concept of interdependent NVU components and distinguishes NF-L, CNP and AQP4 as highly ischemia-sensitive elements. Consequently, future therapeutic approaches might influence stroke evolution via strategies simultaneously addressing both neuronal and glial functions.

Translation and validation of the stroke specific quality of life scale into Arabic

BACKGROUND

There is a need to validate one of the specific stroke quality of life (QOL) scales into Arabic.

OBJECTIVE

To translate and validate the stroke specific quality of life (SSQOL) into Arabic.

METHODS

The SSQOL was translated into Arabic (SSQOL-A) according to a forward/backward translation protocol. 147 first time stroke survivors and 60 healthy subjects were recruited. Cronbach's α was used to measure internal consistency, test-retest reliability was measured by intraclass correlation coefficient (ICC). Acceptability was established by studying floor and ceiling effects. A linear correlation between SSQOL-A and the Short Form 36, the Beck Depression Inventory II, the Barthel Index and the National Institutes of Health Stroke Scale was done to assess construct validity. Discriminant and convergent validity were evaluated by correlating item to scale of each of the domains using Pearson correlation (rp).

RESULTS

The SSQOL-A has shown good internal consistency (Cronbach's α  = 0.78-0.94) and test-retest reliability (ICC = 0.77-0.94). It has also shown acceptable construct validity (r2 = 0.06-0.55). Item to scale correlation showed acceptable convergent (0.76-0.98) and discriminant (0.12-0.53) validity. Mann-Whitney U test showed the ability of the SSQOL-A to differentiate between stroke survivors and healthy participants QOL.

CONCLUSIONS

SSQOL-A has good validity and reliability for patients with mild to moderate stroke.

Structural plasticity of the hippocampus in response to estrogens in female rodents

It is well established that estrogens affect neuroplasticity in a number of brain regions. In particular, estrogens modulate and mediate spine and synapse formation as well as neurogenesis in the hippocampal formation. In this review, we discuss current research exploring the effects of estrogens on dendritic spine plasticity and neurogenesis with a focus on the modulating factors of sex, age, and pregnancy. Hormone levels, including those of estrogens, fluctuate widely across the lifespan from early life to puberty, through adulthood and into old age, as well as with pregnancy and parturition. Dendritic spine formation and modulation are altered both by rapid (likely non-genomic) and classical (genomic) actions of estrogens and have been suggested to play a role in the effects of estrogens on learning and memory. Neurogenesis in the hippocampus is influenced by age, the estrous cycle, pregnancy, and parity in female rodents. Furthermore, sex differences exist in hippocampal cellular and molecular responses to estrogens and are briefly discussed throughout. Understanding how structural plasticity in the hippocampus is affected by estrogens and how these effects can influence function and be influenced by other factors, such as experience and sex, is critical and can inform future treatments in conditions involving the hippocampus.

Sex Differences in Ischemia/Reperfusion Injury: The Role of Mitochondrial Permeability Transition

Brain and heart ischemia are among the leading causes of death and disability in both men and women, but there are significant sex differences in the incidence and severity of these diseases. Ca²⁺ dysregulation in response to ischemia/reperfusion injury (I/RI) is a well-recognized pathogenic mechanism leading to the death of affected cells. Excess intracellular Ca²⁺ causes mitochondrial matrix Ca²⁺ overload that can result in mitochondrial permeability transition (MPT), which can have severe consequences for mitochondrial function and trigger cell death. Recent findings indicate that estrogens and their related receptors are involved in the regulation of MPT, suggesting that sex differences in I/RI could be linked to estrogen-dependent modulation of mitochondrial Ca²⁺. Here, we review the evidence supporting sex differences in I/RI and the role of estrogen and estrogen receptors in producing these differences, the involvement of mitochondrial Ca²⁺ overload in disease pathogenesis, and the estrogen-dependent modulation of MPT that may contribute to sex differences.

Contributions of sex to cerebrovascular function and pathology

Sex differences exist in how cerebral blood vessels function under both physiological and pathological conditions, contributing to observed sex differences in risk and outcomes of cerebrovascular diseases (CBVDs), such as vascular contributions to cognitive impairment and dementia (VCID) and stroke. Throughout most of the lifespan, women are protected from CBVDs; however, risk increases following menopause, suggesting sex hormones may play a significant role in this protection. The cerebrovasculature is a target for sex hormones, including estrogens, progestins, and androgens, where they can influence numerous vascular functions and pathologies. While there is a plethora of information on estrogen, the effects of progestins and androgens on the cerebrovasculature are less well-defined. Estrogen decreases cerebral tone and increases cerebral blood flow, while androgens increase tone. Both estrogens and androgens enhance angiogenesis/cerebrovascular remodeling. While both estrogens and androgens attenuate cerebrovascular inflammation, pro-inflammatory effects of androgens under physiological conditions have also been demonstrated. Sex hormones exert additional neuroprotective effects by attenuating oxidative stress and maintaining integrity and function of the blood brain barrier. Most animal studies utilize young, healthy, gonadectomized animals, which do not mimic the clinical conditions of aging individuals likely to get CBVDs. This is also concerning, as sex hormones appear to mediate cerebrovascular function differently based on age and disease state (e.g. metabolic syndrome). Through this review, we hope to inspire others to consider sex as a key biological variable in cerebrovascular research, as greater understanding of sex differences in cerebrovascular function will assist in developing personalized approaches to prevent and treat CBVDs.

How do neurologists diagnose transient ischemic attack: A systematic review

Background

Identifying and treating patients with transient ischemic attack is an effective means of preventing stroke. However, making this diagnosis can be challenging, and over a third of patients referred to stroke prevention clinic are ultimately found to have alternate diagnoses.

Aims

We performed a systematic review to determine how neurologists diagnose transient ischemic attack.

Summary of review

A systematic literature search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using MEDLINE, Embase, and the Cochrane Library databases. Publications eligible for inclusion were those that included information on the demographic or clinical features neurologists use to diagnose transient ischemic attacks or transient ischemic attack–mimics. Of 1666 citations, 210 abstracts were selected for full-text screening and 80 publications were ultimately deemed eligible for inclusion. Neurologists were more likely to diagnose transient ischemic attack based on clinical features including negative symptoms or speech deficits. Patients with positive symptoms, altered level of consciousness, or the presence of nonfocal symptoms such as confusion or amnesia were more likely to be diagnosed with transient ischemic attack–mimic. Neurologists commonly include mode of onset (i.e. sudden versus gradual), recurrence of attacks, and localizability of symptoms to a distinct vascular territory in the diagnostic decision-making process. Transient ischemic attack diagnosis was more commonly associated with advanced age, preexisting hypertension, atrial fibrillation, and other vascular risk factors.

Conclusions

Neurologists rely on certain clinical and demographic features to distinguish transient ischemic attacks from mimics, which are not currently reflected in widely used risk scores. Clarifying how neurologists diagnose transient ischemic attack may help frontline clinicians to better select patients for referral to stroke prevention clinics.

Sex differences in risk factors for vascular contributions to cognitive impairment & dementia

Vascular contributions to cognitive impairment and dementia (VCID) is the second most common cause of dementia. While males overall appear to be at a slightly higher risk for VCID throughout most of the lifespan (up to age 85), some risk factors for VCID more adversely affect women. These include female-specific risk factors associated with pregnancy related disorders (e.g. preeclampsia), menopause, and poorly timed hormone replacement. Further, presence of certain co-morbid risk factors, such as diabetes, obesity and hypertension, also may more adversely affect women than men. In contrast, some risk factors more greatly affect men, such as hyperlipidemia, myocardial infarction, and heart disease. Further, stroke, one of the leading risk factors for VCID, has a higher incidence in men than in women throughout much of the lifespan, though this trend is reversed at advanced ages. This review will highlight the need to take biological sex and common co-morbidities for VCID into account in both preclinical and clinical research. Given that there are currently no treatments available for VCID, it is critical that we understand how to mitigate risk factors for this devastating disease in both sexes.

MicroRNA-based therapeutics in central nervous system injuries

Central nervous system (CNS) injuries, such as stroke, traumatic brain injury (TBI) and spinal cord injury (SCI), are important causes of death and long-term disability worldwide. MicroRNA (miRNA), small non-coding RNA molecules that negatively regulate gene expression, can serve as diagnostic biomarkers and are emerging as novel therapeutic targets for CNS injuries. MiRNA-based therapeutics include miRNA mimics and inhibitors (antagomiRs) to respectively decrease and increase the expression of target genes. In this review, we summarize current miRNA-based therapeutic applications in stroke, TBI and SCI. Administration methods, time windows and dosage for effective delivery of miRNA-based drugs into CNS are discussed. The underlying mechanisms of miRNA-based therapeutics are reviewed including oxidative stress, inflammation, apoptosis, blood-brain barrier protection, angiogenesis and neurogenesis. Pharmacological agents that protect against CNS injuries by targeting specific miRNAs are presented along with the challenges and therapeutic potential of miRNA-based therapies.

Estrogen receptor beta modulates permeability transition in brain mitochondria

Recent evidence highlights a role for sex and hormonal status in regulating cellular responses to ischemic brain injury and neurodegeneration. A key pathological event in ischemic brain injury is the opening of a mitochondrial permeability transition pore (MPT) induced by excitotoxic calcium levels, which can trigger irreversible damage to mitochondria accompanied by the release of pro-apoptotic factors. However, sex differences in brain MPT modulation have not yet been explored. Here, we show that mitochondria isolated from female mouse forebrain have a lower calcium threshold for MPT than male mitochondria, and that this sex difference depends on the MPT regulator cyclophilin D (CypD). We also demonstrate that an estrogen receptor beta (ERβ) antagonist inhibits MPT and knockout of ERβ decreases the sensitivity of mitochondria to the CypD inhibitor, cyclosporine A. These results suggest a functional relationship between ERβ and CypD in modulating brain MPT. Moreover, co-immunoprecipitation studies identify several ERβ binding partners in mitochondria. Among these, we investigate the mitochondrial ATPase as a putative site of MPT regulation by ERβ. We find that previously described interaction between the oligomycin sensitivity-conferring subunit of ATPase (OSCP) and CypD is decreased by ERβ knockout, suggesting that ERβ modulates MPT by regulating CypD interaction with OSCP. Functionally, in primary neurons and hippocampal slice cultures, modulation of ERβ has protective effects against glutamate toxicity and oxygen glucose deprivation, respectively. Taken together, these results reveal a novel pathway of brain MPT regulation by ERβ that could contribute to sex differences in ischemic brain injury and neurodegeneration.

Nicotine Alters Estrogen Receptor-Beta-Regulated Inflammasome Activity and Exacerbates Ischemic Brain Damage in Female Rats

Smoking is a preventable risk factor for stroke and smoking-derived nicotine exacerbates post-ischemic damage via inhibition of estrogen receptor beta (ER-β) signaling in the brain of female rats. ER-β regulates inflammasome activation in the brain. Therefore, we hypothesized that chronic nicotine exposure activates the inflammasome in the brain, thus exacerbating ischemic brain damage in female rats. To test this hypothesis, adult female Sprague-Dawley rats (6–7 months old) were exposed to nicotine (4.5 mg/kg/day) or saline for 16 days. Subsequently, brain tissue was collected for immunoblot analysis. In addition, another set of rats underwent transient middle cerebral artery occlusion (tMCAO; 90 min) with or without nicotine exposure. One month after tMCAO, histopathological analysis revealed a significant increase in infarct volume in the nicotine-treated group (64.24 ± 7.3 mm³; mean ± SEM; n = 6) compared to the saline-treated group (37.12 ± 7.37 mm³; n = 7, p < 0.05). Immunoblot analysis indicated that nicotine increased cortical protein levels of caspase-1, apoptosis-associated speck-like protein containing a CARD (ASC) and pro-inflammatory cytokines interleukin (IL)-1β by 88% (p < 0.05), 48% (p < 0.05) and 149% (p < 0.05), respectively, when compared to the saline-treated group. Next, using an in vitro model of ischemia in organotypic slice cultures, we tested the hypothesis that inhibition of nicotine-induced inflammasome activation improves post-ischemic neuronal survival. Accordingly, slices were exposed to nicotine (100 ng/mL; 14–16 days) or saline, followed by treatment with the inflammasome inhibitor isoliquiritigenin (ILG; 24 h) prior to oxygen-glucose deprivation (OGD; 45 min). Quantification of neuronal death demonstrated that inflammasome inhibition significantly decreased nicotine-induced ischemic neuronal death. Overall, this study shows that chronic nicotine exposure exacerbates ischemic brain damage via activation of the inflammasome in the brain of female rats.

Gender differences in the use of cardiovascular interventions in HIV-positive persons; the D:A:D Study

INTRODUCTION

There is paucity of data related to potential gender differences in the use of interventions to prevent and treat cardiovascular disease (CVD) among HIV-positive individuals. We investigated whether such differences exist in the observational D:A:D cohort study.

METHODS

Participants were followed from study enrolment until the earliest of death, six months after last visit or February 1, 2015. Initiation of CVD interventions [lipid-lowering drugs (LLDs), angiotensin-converting enzyme inhibitors (ACEIs), anti-hypertensives, invasive cardiovascular procedures (ICPs) were investigated and Poisson regression models calculated whether rates were lower among women than men, adjusting for potential confounders.

RESULTS

Women (n = 12,955) were generally at lower CVD risk than men (n = 36,094). Overall, initiation rates of CVD interventions were lower in women than men; LLDs: incidence rate 1.28 [1.21, 1.35] vs. 2.40 [2.34, 2.46]; ACEIs: 0.88 [0.82, 0.93] vs. 1.43 [1.39, 1.48]; anti-hypertensives: 1.40 [1.33, 1.47] vs. 1.72 [1.68, 1.77] and ICPs: 0.08 [0.06, 0.10] vs. 0.30 [0.28, 0.32], and this was also true for most CVD interventions when exclusively considering periods of follow-up for which individuals were at high CVD risk. In fully adjusted models, women were less likely to receive CVD interventions than men (LLDs: relative rate 0.83 [0.78, 0.88]; ACEIs: 0.93 [0.86, 1.01]; ICPs: 0.54 [0.43, 0.68]), except for the receipt of anti-hypertensives (1.17 [1.10, 1.25]).

CONCLUSION

The use of most CVD interventions was lower among women than men. Interventions are needed to ensure that all HIV-positive persons, particularly women, are appropriately monitored for CVD and, if required, receive appropriate CVD interventions.

Pharmacological thrombolysis for acute ischemic stroke treatment: Gender differences in clinical risk factors

BACKGROUND

In a stroke population, women have a worse outcome than men when untreated. In contrast, there is no significant difference in treated patients. In this study, we determined whether clinical variables represent a promising approach to assist in the evaluation of gender differences in a stroke population.

METHODS

We analyzed data from ischemic stroke patients' ≥18 years-old from the stroke registry on rtPA administration and identified gender differences in clinical factors within inclusion and exclusion criteria in a stroke population that received rtPA. Multivariate analysis was used to adjust for patient demographic and clinical variables.

RESULTS

Of the 241 eligible stroke patients' thrombolytic therapy, 49.4% were females and 50.6% were males. Of the 422 patients that did not receive rtPA, more women (235) were excluded from rtPA than men (187) (P<0.05). In the male population, exclusion from rtPA was associated with history of a previous stroke (P<0.05, OR=2.028), hypertension (P<0.05, OR=0.519), and NIH stroke score (P<0.0001, OR=0.893). In female stroke patients, exclusion from rtPA was associated with previous history of stroke (P<0.05, OR=2.332), diabetes (P<0.05, OR=1.88) and NIH stroke score (P<0.05, OR=0.916).

CONCLUSIONS

Despite similarities in different areas of stroke care for both men and women, more women with diabetes, previous history of stroke and higher NIH scores are more likely to be excluded from thrombolytic therapy. Men with a previous history of stroke, hypertension and higher NIH scores are more likely to be excluded rtPA even after adjustment for confounding variables.

Steroid Transport, Local Synthesis, and Signaling within the Brain: Roles in Neurogenesis, Neuroprotection, and Sexual Behaviors

Sex steroid hormones are synthesized from cholesterol and exert pleiotropic effects notably in the central nervous system. Pioneering studies from Baulieu and colleagues have suggested that steroids are also locally-synthesized in the brain. Such steroids, called neurosteroids, can rapidly modulate neuronal excitability and functions, brain plasticity, and behavior. Accumulating data obtained on a wide variety of species demonstrate that neurosteroidogenesis is an evolutionary conserved feature across fish, birds, and mammals. In this review, we will first document neurosteroidogenesis and steroid signaling for estrogens, progestagens, and androgens in the brain of teleost fish, birds, and mammals. We will next consider the effects of sex steroids in homeostatic and regenerative neurogenesis, in neuroprotection, and in sexual behaviors. In a last part, we will discuss the transport of steroids and lipoproteins from the periphery within the brain (and vice-versa) and document their effects on the blood-brain barrier (BBB) permeability and on neuroprotection. We will emphasize the potential interaction between lipoproteins and sex steroids, addressing the beneficial effects of steroids and lipoproteins, particularly HDL-cholesterol, against the breakdown of the BBB reported to occur during brain ischemic stroke. We will consequently highlight the potential anti-inflammatory, anti-oxidant, and neuroprotective properties of sex steroid and lipoproteins, these latest improving cholesterol and steroid ester transport within the brain after insults.

Challenges in Sex- and Gender-Centered Prevention and Management of Cardiovascular Disease: Implications of Genetic, Metabolic, and Environmental Paths

The recognition of cardiovascular disease (CVD) as a "male" privilege has been a commonly held concept. However, emerging data describe another reality. Heterogeneities have been convincingly demonstrated regarding CVD manifestations, risk factor burden, and prognosis between males and females. The aim of the present narrative review was to highlight sex- and gender-related discrepancies in primary and secondary CVD prevention, underscoring plausible underlying mechanisms. Manifestation of CVD in women is characterized by atypical symptoms/signs and inadequately studied pathophysiology features challenging accurate diagnosis and effective treatment. Regarding CVD risk assessment, the burden and effect size of conventional, novel, and female-specific risk factors needs better clarification. Hitherto outcomes are nonconsistent, while most importantly, the interpretation of the attendant metabolic paths remains a challenge; the interactions among genetic, metabolic, and environmental factors are of high complexity regulated by genomic and nongenomic sex hormones effects. To deal with these key points, the National Institutes of Health currently calls upon investigators to provide a sex- and gender-specific reporting in all health research hypotheses. The implementation of high-quality studies addressing these issues is an imperative need to maximize cost-effectiveness in prevention and management strategies.

Immunosignals of Oligodendrocyte Markers and Myelin-Associated Proteins Are Critically Affected after Experimental Stroke in Wild-Type and Alzheimer Modeling Mice of Different Ages

Because stroke therapies are still limited and patients are often concerned by long-term sequelae with significant impairment of daily living, elaborated neuroprotective strategies are needed. During the last decades, research substantially improved the knowledge on cellular pathologies responsible for stroke-related tissue damage. In this context, the neurovascular unit (NVU) concept has been established, summarizing the affections of neurons, associated astrocytes and the vasculature. Although oligodendrocytes were already identified to play a major role in other brain pathologies, their role during stroke evolution and long-lasting tissue damage is poorly understood. This study aims to explore oligodendrocyte structures, i.e., oligodendrocytes and their myelin-associated proteins, after experimental focal cerebral ischemia. For translational issues, different ages and genotypes including an Alzheimer-like background were considered to mimic potential co-morbidities. Three- and 12-month-old wild-type and triple-transgenic mice were subjected to unilateral middle cerebral artery occlusion. Immunofluorescence labeling was performed on forebrain tissues affected by 24 h of ischemia to visualize the oligodendrocyte-specific protein (OSP), the myelin basic protein (MBP), and the neuron-glia antigen 2 (NG2) with reference to the ischemic lesion. Subsequent analyses concomitantly detected the vasculature and the 2′, 3′-cyclic nucleotide-3′-phosphodiesterase (CNPase) to consider the NVU concept and to explore the functional relevance of histochemical data on applied oligodendrocyte markers. While the immunosignal of NG2 was found to be nearly absent 24 h after ischemia onset, enhanced immunoreactivities for OSP and especially MBP were observed in close regional association to the vasculature. Added quantitative analyses based on inter-hemispheric differences of MBP-immunoreactivity revealed a shell-like pattern with a significant increase directly in the ischemic core, followed by a gradual decline toward the striatum, the ischemic border zone and the lateral neocortex. This observation was consistent in subsequent analyses on the potential impact of age and genetic background. Furthermore, immunoreactivities for CNPase, MBP, and OSP were found to be simultaneously enhanced. In conclusion, this study provides evidence for a critical role of oligodendrocyte structures in the early phase after experimental stroke, strengthening their involvement in the ischemia-affected NVU. Consequently, oligodendrocytes and their myelin-associated proteins may qualify as potential targets for neuroprotective and regenerative approaches in stroke.

Between mind and heart: Sex-based cognitive bias in cardiovascular disease treatment

Given that both men and women experience cardiovascular disease (CVD), a common misconception is that they have similar risk factors and clinical presentation, receive comparable treatment, and have equivalent clinical outcomes; in reality differences are observed between men and women for each of these endpoints. Moreover, these differences occur as a function of both gender and sex. A review of the literature reveals widespread bias in the selection of research subjects based on these factors, in addition to implicit patient and provider biases that impede the access of women to recommended primary and secondary CVD management. In this perspective, we identify strategies to eliminate such biases and improve women's access to CVD treatments to ensure their care is consistent with current guidelines.