Sex, stroke, and inflammation: the potential for estrogen-mediated immunoprotection in stroke

J-shaped associations of pan-immune-inflammation value and systemic inflammation response index with stroke among American adults with hypertension: evidence from NHANES 1999-2020

Introduction

Stroke, a leading cause of death and disability worldwide, is primarily ischemic and linked to hypertension. Hypertension, characterized by systemic chronic inflammation, significantly increases stroke risk. This study explores the association of novel systemic inflammatory markers (SII, PIV, SIRI) with stroke prevalence in hypertensive U.S. adults using NHANES data.

Methods

We analyzed data from hypertensive participants in the NHANES 1999-2020 survey, excluding those under 20, pregnant, or with missing data, resulting in 18,360 subjects. Systemic inflammatory markers (SII, PIV, SIRI) were calculated from blood counts. Hypertension and stroke status were determined by self-report and clinical measurements. Covariates included sociodemographic, lifestyle, and medical history factors. Weighted statistical analyses and multivariate logistic regression models were used to explore associations, with adjustments for various covariates. Ethical approval was obtained from the NCHS Ethics Review Board.

Results

In a cohort of 18,360 hypertensive individuals (mean age 56.652 years), 7.25% had a stroke. Stroke patients were older, had lower PIR, and were more likely to be female, single, less educated, smokers, non-drinkers, physically inactive, and have diabetes and CHD. Multivariate logistic regression showed that SII was not significantly associated with stroke. However, PIV and SIRI were positively associated with stroke prevalence. Each unit increase in lnPIV increased stroke odds by 14% (OR = 1.140, p = 0.0022), and lnSIRI by 20.6% (OR = 1.206, p = 0.0144). RCS analyses confirmed J-shaped associations for lnPIV and lnSIRI with stroke. Stratified analyses identified gender and smoking as significant effect modifiers. Smoking was significantly associated with elevated PIV, SIRI, and SII levels, especially in current smokers.

Conclusion

Elevated PIV and SIRI levels significantly increase stroke prevalence in hypertensive individuals, notably among males and smokers. A predictive model with PIV, SIRI, and sociodemographic factors offers strong clinical utility.

Gut-Brain Axis: Focus on Sex Differences in Neuroinflammation

In recent years, there has been a growing interest in the concept of the "gut-brain axis". In addition to well-studied diseases associated with an imbalance in gut microbiota, such as cancer, chronic inflammation, and cardiovascular diseases, research is now exploring the potential role of gut microbial dysbiosis in the onset and development of brain-related diseases. When the function of the intestinal barrier is altered by dysbiosis, the aberrant immune system response interacts with the nervous system, leading to a state of "neuroinflammation". The gut microbiota-brain axis is mediated by inflammatory and immunological mechanisms, neurotransmitters, and neuroendocrine pathways. This narrative review aims to illustrate the molecular basis of neuroinflammation and elaborate on the concept of the gut-brain axis by virtue of analyzing the various metabolites produced by the gut microbiome and how they might impact the nervous system. Additionally, the current review will highlight how sex influences these molecular mechanisms. In fact, sex hormones impact the brain-gut microbiota axis at different levels, such as the central nervous system, the enteric nervous one, and enteroendocrine cells. A deeper understanding of the gut-brain axis in human health and disease is crucial to guide diagnoses, treatments, and preventive interventions.

Immunomodulatory role of estrogen in ischemic stroke: neuroinflammation and effect of sex

Although estrogen is predominantly related to the maintenance of reproductive functioning in females, it mediates various physiological effects in nearly all tissues, especially the central nervous system. Clinical trials have revealed that estrogen, especially 17β-estradiol, can attenuate cerebral damage caused by an ischemic stroke. One mechanism underlying this effect of 17β-estradiol is by modulating the responses of immune cells, indicating its utility as a novel therapeutic strategy for ischemic stroke. The present review summarizes the effect of sex on ischemic stroke progression, the role of estrogen as an immunomodulator in immune reactions, and the potential clinical value of estrogen replacement therapy. The data presented here will help better understand the immunomodulatory function of estrogen and may provide a basis for its novel therapeutic use in ischemic stroke.

Spatiotemporal Cofilin Signaling, Microglial Activation, Neuroinflammation, and Cognitive Impairment Following Hemorrhagic Brain Injury

Intracerebral hemorrhage (ICH) is a significant health concern associated with high mortality. Cofilin plays a crucial role in stress conditions, but its signaling following ICH in a longitudinal study is yet to be ascertained. In the present study, we examined the cofilin expression in human ICH autopsy brains. Then, the spatiotemporal cofilin signaling, microglia activation, and neurobehavioral outcomes were investigated in a mouse model of ICH. Human autopsy brain sections from ICH patients showed increased intracellular cofilin localization within microglia in the perihematomal area, possibly associated with microglial activation and morphological changes. Various cohorts of mice were subjected to intrastriatal collagenase injection and sacrificed at time points of 1, 3, 7, 14, 21, and 28 days. Mice suffered from severe neurobehavioral deficits after ICH, lasting for 7 days, followed by a gradual improvement. Mice suffered post-stroke cognitive impairment (PSCI) both acutely and in the chronic phase. Hematoma volume increased from day 1 to 3, whereas ventricle size increased from day 21 to 28. Cofilin protein expression increased in the ipsilateral striatum on days 1 and 3 and then decreased from days 7 to 28. An increase in activated microglia was observed around the hematoma on days 1 to 7, followed by a gradual reduction up to day 28. Around the hematoma, activated microglia showed morphological changes from ramified to amoeboid. mRNA levels of inflammatory [tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), and interleukin-6 (IL-6) and anti-inflammatory markers [interleukin-10 (IL-10), transforming growth factor-β TGF-β, and arginase I (Arg1)] increased during the acute phase and decreased in the chronic phase. Blood cofilin levels increased on day 3 and matched the increase in chemokine levels. slingshot protein phosphatase 1 (SSH1) protein, which activates cofilin, was increased from day 1 to 7. These results suggest that microglial activation might be the sequel of cofilin overactivation following ICH, leading to widespread neuroinflammation and consequent PSCI.

Post-stroke periodic estrogen receptor-beta agonist improves cognition in aged female rats

Women have a higher risk of having an ischemic stroke and increased cognitive decline after stroke as compared to men. The female sex hormone 17β-estradiol (E2) is a potent neuro- and cognitive-protective agent. Periodic E2 or estrogen receptor subtype-beta (ER-β) agonist pre-treatments every 48 h before an ischemic episode ameliorated ischemic brain damage in young ovariectomized or reproductively senescent (RS) aged female rats. The current study aims to investigate the efficacy of post-stroke ER-β agonist treatments in reducing ischemic brain damage and cognitive deficits in RS female rats. Retired breeder (9-10 months) Sprague-Dawley female rats were considered RS after remaining in constant diestrus phase for more than a month. The RS rats were exposed to transient middle cerebral artery occlusion (tMCAO) for 90 min and treated with either ER-β agonist (beta 2, 3-bis(4-hydroxyphenyl) propionitrile; DPN; 1 mg/kg; s.c.) or DMSO vehicle at 4.5 h after induction of tMCAO. Subsequently, rats were treated with either ER-β agonist or DMSO vehicle every 48 h for ten injections. Forty-eight hours after the last treatment, animals were tested for contextual fear conditioning to measure post-stroke cognitive outcome. Neurobehavioral testing, infarct volume quantification, and hippocampal neuronal survival were employed to determine severity of stroke. Periodic post-stroke ER-β agonist treatment reduced infarct volume, improved recovery of cognitive capacity by increasing freezing in contextual fear conditioning, and decreased hippocampal neuronal death in RS female rats. These data suggest that periodic post-stroke ER-β agonist treatment to reduce stroke severity and improve post-stroke cognitive outcome in menopausal women has potential for future clinical investigation.

Immune regulation based on sex differences in ischemic stroke pathology

Ischemic stroke is one of the world's leading causes of death and disability. It has been established that gender differences in stroke outcomes prevail, and the immune response after stroke is an important factor affecting patient outcomes. However, gender disparities lead to different immune metabolic tendencies closely related to immune regulation after stroke. The present review provides a comprehensive overview of the role and mechanism of immune regulation based on sex differences in ischemic stroke pathology.

Sexual dimorphism in immune cell responses following stroke

Recent bodies of work in regard to stroke have revealed significant sex differences in terms of risk and outcome. While differences in sex hormones have been the focus of earlier research, the reasons for these differences are much more complex and require further identification. This review covers differences in sex related immune responses with a focus on differences in immune cell composition and function. While females are more susceptible to immune related diseases, they seem to have better outcomes from stroke at the experimental level with reduced pro-inflammatory responses. However, at the clinical level, the picture is much more complex with worse neurological outcomes from stroke. While the use of exogenous sex steroids can replicate some of these findings, it is apparent that many other factors are involved in the modulation of immune responses. As a result, more research is needed to better understand these differences and identify appropriate interventions and risk modification.

Ki20227 aggravates apoptosis, inflammatory response, and oxidative stress after focal cerebral ischemia injury

The survival of microglia depends on the colony-stimulating factor-1 receptor (CSF1R) signaling pathway under physiological conditions. Ki20227 is a highly selective CSF1R inhibitor that has been shown to change the morphology of microglia. However, the effects of Ki20227 on the progression of ischemic stroke are unclear. In this study, male C57BL/6 mouse models of focal cerebral ischemic injury were established through the occlusion of the middle cerebral artery and then administered 3 mg/g Ki20227 for 3 successive days. The results revealed that the number of ionized calcium-binding adaptor molecule 1/bromodeoxyuridine double positive cells in the infarct tissue was reduced, the degree of edema was increased, neurological deficits were aggravated, infarct volume was increased, and the number of peri-infarct Nissl bodies was reduced. The number of terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive cells in the peri-infarct tissue was increased. The expression levels of Bax and Cleaved caspase-3 were up-regulated. Bcl-2 expression was downregulated. The expression levels of inflammatory factors and oxidative stress-associated factors were increased. These findings suggested that Ki20227 blocked microglial proliferation and aggravated the pathological progression of ischemia/reperfusion injury in a transient middle cerebral artery occlusion model. This study was approved by the Animal Ethics Committee of Lanzhou University Second Hospital (approval No. D2020-68) on March 6, 2020.

Reproduction-Associated Hormones and Adult Hippocampal Neurogenesis

The levels of reproduction-associated hormones in females, such as estrogen, progesterone, prolactin, and oxytocin, change dramatically during pregnancy and postpartum. Reproduction-associated hormones can affect adult hippocampal neurogenesis (AHN), thereby regulating mothers' behavior after delivery. In this review, we first briefly introduce the overall functional significance of AHN and the methods commonly used to explore this front. Then, we attempt to reconcile the changes of reproduction-associated hormones during pregnancy. We further update the findings on how reproduction-related hormones influence adult hippocampal neurogenesis. This review is aimed at emphasizing a potential role of AHN in reproduction-related brain plasticity and its neurobiological relevance to motherhood behavior.

Exogenous inter-α inhibitor proteins prevent cell death and improve ischemic stroke outcomes in mice

Inter-α inhibitor proteins (IAIPs) are a family of endogenous plasma and extracellular matrix molecules. IAIPs suppress proinflammatory cytokines, limit excess complement activation, and bind extracellular histones to form IAIP-histone complexes, leading to neutralization of histone-associated cytotoxicity in models of sepsis. Many of these detrimental processes also play critical roles in the pathophysiology of ischemic stroke. In this study, we first assessed the clinical relevance of IAIPs in stroke and then tested the therapeutic efficacy of exogenous IAIPs in several experimental stroke models. IAIP levels were reduced in both ischemic stroke patients and in mice subjected to experimental ischemic stroke when compared with controls. Post-stroke administration of IAIP significantly improved stroke outcomes across multiple stroke models, even when given 6 hours after stroke onset. Importantly, the beneficial effects of delayed IAIP treatment were observed in both young and aged mice. Using targeted gene expression analysis, we identified a receptor for complement activation, C5aR1, that was highly suppressed in both the blood and brain of IAIP-treated animals. Subsequent experiments using C5aR1-knockout mice demonstrated that the beneficial effects of IAIPs are mediated in part by C5aR1. These results indicate that IAIP is a potential therapeutic candidate for the treatment of ischemic stroke.

The Impact of Sex on Arterial Ischemic Stroke in Young Patients: From Stroke Occurrence to Poststroke Consequences

The male sex has been suggested to predominate in paediatric patients with arterial ischemic stroke (AIS), especially in newborns. The explanation for this phenomenon remains unsatisfactory since it focuses on the analysis of the potential relationship with trauma and arterial dissection. In turn, in some populations of young adults, men suffer from AIS more frequently than women, which may be related to the protective role of oestrogen. On the other hand, certain data indicate that women dominate over men. Some of the disparities in the frequencies of particular symptoms of AIS and poststroke consequences in both children and young adults have been suggested; however, data are scarce. Unfortunately, the low number of studies on the subject does not allow certain conclusions to be drawn. For adults, more data are available for patients aged over 60 years, the results of which are more obvious. The present literature review aimed to discuss available data on the prevalence of AIS, its clinical presentations, and poststroke consequences in regard to the sex of young patients. We considered young patients to be children from birth up to the age of 19 years of life and young adults to be individuals up to the age of 55 years. The role of sex hormones in AIS and possible gender differences in genetic risk factors for AIS were also discussed briefly.

Can quantifying morphology and TMEM119 expression distinguish between microglia and infiltrating macrophages after ischemic stroke and reperfusion in male and female mice?

Background

Ischemic stroke is an acquired brain injury with gender-dependent outcomes. A persistent obstacle in understanding the sex-specific neuroinflammatory contributions to ischemic brain injury is distinguishing between resident microglia and infiltrating macrophages—both phagocytes—and determining cell population-specific contributions to injury evolution and recovery processes. Our purpose was to identify microglial and macrophage populations regulated by ischemic stroke using morphology analysis and the presence of microglia transmembrane protein 119 (TMEM119). Second, we examined sex and menopause differences in microglia/macrophage cell populations after an ischemic stroke.

Methods

Male and female, premenopausal and postmenopausal, mice underwent either 60 min of middle cerebral artery occlusion and 24 h of reperfusion or sham surgery. The accelerated ovarian failure model was used to model postmenopause. Brain tissue was collected to quantify the infarct area and for immunohistochemistry and western blot methods. Ionized calcium-binding adapter molecule, TMEM119, and confocal microscopy were used to analyze the microglia morphology and TMEM119 area in the ipsilateral brain regions. Western blot was used to quantify protein quantity.

Results

Post-stroke injury is increased in male and postmenopause female mice vs. premenopause female mice (p < 0.05) with differences primarily occurring in the caudal sections. After stroke, the microglia underwent a region, but not sex group, dependent transformation into less ramified cells (p < 0.0001). However, the number of phagocytic microglia was increased in distal ipsilateral regions of postmenopausal mice vs. the other sex groups (p < 0.05). The number of TMEM119-positive cells was decreased in proximity to the infarct (p < 0.0001) but without a sex group effect. Two key findings prevented distinguishing microglia from systemic macrophages. First, morphological data were not congruent with TMEM119 immunofluorescence data. Cells with severely decreased TMEM119 immunofluorescence were ramified, a distinguishing microglia characteristic. Second, whereas the TMEM119 immunofluorescence area decreased in proximity to the infarcted area, the TMEM119 protein quantity was unchanged in the ipsilateral hemisphere regions using western blot methods.

Conclusions

Our findings suggest that TMEM119 is not a stable microglia marker in male and female mice in the context of ischemic stroke. Until TMEM119 function in the brain is elucidated, its use to distinguish between cell populations following brain injury with cell infiltration is cautioned.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02105-2.

Temporal, geographical and demographic trends of stroke prevalence in China: a systematic review and meta-analysis

Background

China has made large efforts to reduce stroke prevalence. We aimed to systematically examine the prevalence of stroke in China over the past two decades.

Methods

Databases, including China National Knowledge Infrastructure, Wanfang, VIP, and PubMed, were systematically searched for studies published in English or Chinese that reported stroke prevalence in China during 2000–2017. Meta-analysis was conducted to estimate the pooled stroke prevalence and the variations in stroke prevalence subgroups stratified by age, gender, time period, and region.

Results

In total, 96 papers met the inclusion criteria. Meta-analysis showed that the overall estimated national prevalence was 5.1% (5.0–5.3%) with large variations across regions: 3.1% (2.5–3.6%) in south China, 3.4% (3.0–3.8%) in southwest China, 3.6% (3.3–3.8%) in east China, 5.0% (4.7–5.4%) in central China, 5.8% (4.6–7.1%) in northwest China, 6.0% (5.0–7.0%) in northeast China, and 8.0% (7.4–8.5%) in north China. Men had a higher prevalence than women [7.3% (6.9–7.7%) vs. 5.6% (5.2–6.0%)]. Stroke prevalence increased with age, was 1.2% (1.0–1.3%), 2.9% (2.6–3.2%), 5.9% (5.2–6.5%), and 8.7% (8.0–9.5%) in the 40–49, 50–59, 60–69, and ≥70 years old groups, respectively.

Conclusions

Men, people being older, or living in northern China had higher stroke prevalence. More vigorous efforts are needed in China to prevent stroke.

Does the Occurrence of Particular Symptoms and Outcomes of Arterial Ischemic Stroke Depend on Sex in Pediatric Patients?-A Pilot Study

Arterial ischemic stroke (AIS) in childhood is reported to occur more frequently in boys, which may lead to the assumption that the prevalence of post-stroke deficits is sex related. The present study aimed to evaluate sex-related differences in functional outcomes (hemiparesis, seizures, aphasia, and motor disturbances other than hemiparesis) in pediatric patients with AIS. A total of 89 children (52 boys and 37 girls; mean age at stroke onset: 8.4 ± 5.6 years) were evaluated retrospectively based on data from medical records. The patients were divided into subgroups according to age (i.e., infants and toddlers, children, and adolescents), stroke subtype (i.e., lacunar anterior circulation infarct (LACI), total anterior circulation infarct (TACI), partial anterior circulation infarct (PACI), posterior circulation infarct (POCI)) and stroke location (i.e., anterior stroke, posterior stroke). Significant differences in the prevalence of stroke subtypes between girls and boys were observed (p = 0.034). POCI stroke were found to be more frequent in boys than in girls (OR = 8.57 95%CI 1.05–70.23, p = 0.023). Males predominated in the total group and in all analyzed age subgroups. The proportions of boys within the subgroups according to stroke subtype were extremely high for the POCI and TACI stroke subgroups. On the other hand, girls predominated in the LACI stroke subgroup. Frequency of central type facial nerve palsy and other symptoms of AIS were found to significantly differ between male subgroups according to stroke subtype (p = 0.050 and p < 0.001, respectively), as well as between children with anterior stroke and those with posterior stroke (p = 0.059 and p < 0.001, respectively). Post-stroke seizures appeared significantly more commonly in girls with TACI and POCI stroke than in girls with LACI and PACI stroke (p = 0.022). In turn, the prevalence of post-stroke hemiparesis differed between stroke subtypes in boys (p = 0.026). In conclusion, sex may have an impact in predisposing to a certain type of AIS in the patient. Post-stroke seizure may be related to stroke subtype in girls and hemiparesis in boys. However, further studies are needed to confirm the results.

Inflammation Induced by Natural Neuronal Death and LPS Regulates Neural Progenitor Cell Proliferation in the Healthy Adult Brain

Inflammation is typically considered a negative response to injury or insult; however, recent advances demonstrate that inflammatory cells regulate development, plasticity, and homeostasis through anticytotoxic, progenerative responses. Here, we extend analyses of neuroinflammation to natural neurodegenerative and homeostatic states by exploiting seasonal plasticity in cytoarchitecture of the avian telencephalic song control nucleus, high vocal center [HVC (proper name)], in the songbird Gambel's white-crowned sparrow (Zonotrichia leucophrys gambelii). We report that local injection of the endotoxin lipopolysaccharide into HVC of birds in both breeding (high circulating testosterone level) and nonbreeding (low circulating testosterone level) conditions increased neural progenitor cell proliferation in the nearby but distinct ventricular zone. Additionally, we found that oral administration of the anti-inflammatory drug minocycline during seasonal regression of HVC reduced microglia activation in HVC and prevented the normal proliferative response in the ventricular zone to apoptosis in HVC. Our results suggest that local neuroinflammation positively regulates neural progenitor cell proliferation and, in turn, contributes to the previously described repatterning of HVC cytoarchitecture following seasonally induced neuronal loss.

Single intranasal administration of 17β-estradiol loaded gelatin nanoparticles confers neuroprotection in the post-ischemic brain

Globally, ischemic stroke is a leading cause of death and adult disability. Previous efforts to repair damaged brain tissue following ischemic events have been hindered by the relative isolation of the central nervous system. We have developed a gelatin nanoparticle-mediated intranasal drug delivery system as an efficient, non-invasive method for delivering 17β-estradiol (E2) specifically to the brain, enhancing neuroprotection, and limiting systemic side effects. Young adult male C57BL/6 J mice subjected to 30 min of middle cerebral artery occlusion (MCAO) were administered intranasal preparations of E2-GNPs, water soluble E2, or saline as control 1 h after reperfusion. Following intranasal administration of 500 ng E2-GNPs, brain E2 content rose by 5.24 fold (P<0.0001) after 30 min and remained elevated by 2.5 fold at 2 h (P<0.05). The 100 ng dose of E2-GNPs reduced mean infarct volume by 54.3% (P<0.05, n=4) in comparison to saline treated controls, demonstrating our intranasal delivery system's efficacy.

Immune System Sex Differences May Bridge the Gap Between Sex and Gender in Fibromyalgia

The fibromyalgia syndrome (FMS) is characterized by chronic widespread pain, sleep disturbances, fatigue, and cognitive alterations. A limited efficacy of targeted treatment and a high FMS prevalence (2–5% of the adult population) sums up to high morbidity. Although, altered nociception has been explained with the central sensitization hypothesis, which may occur after neuropathy, its molecular mechanism is not understood. The marked female predominance among FMS patients is often attributed to a psychosocial predisposition of the female gender, but here we will focus on sex differences in neurobiological processes, specifically those of the immune system, as various immunological biomarkers are altered in FMS. The activation of innate immune sensors is compatible with a neuropathy or virus-induced autoimmune diseases. Considering sex differences in the immune system and the clustering of FMS with autoimmune diseases, we hypothesize that the female predominance in FMS is due to a neuropathy-induced autoimmune pathophysiology. We invite the scientific community to verify the autoimmune hypothesis for FMS.

Neuroinflammation

Neuroinflammation is implicated in contributing to a variety of neurologic and somatic illnesses including Alzheimer's disease (AD), Parkinson's disease (PD), and depression. In this chapter, we focus on the role of neuroinflammation in mediating these three illnesses and portray interactions between the immune response and the central nervous system in the context of sex differences in disease progression. The majority of this chapter is supported by clinical findings; however, we occasionally utilize preclinical models where human studies are currently lacking. We begin by detailing the pathology of neuroinflammation, distinguishing between acute and chronic inflammation, and examining contributions from the innate and adaptive immune systems. Next, we summarize potential mechanisms of immune cell mediators including interleukin-1 beta (IL-1β), tumor necrosis factor α, and IL-6 in AD, PD, and depression development. Given the strong sex bias seen in these illnesses, we additionally examine the role of sex hormones, e.g., estrogen and testosterone in mediating neuroinflammation at the cellular level. Systematically, we detail how sex hormones may contribute to distinct behavioral and clinical symptoms and prognosis between males and females with AD, PD, or depression. Finally, we highlight the possible role of exercise in alleviating neuroinflammation, as well as evidence that antiinflammatory drug therapies improve cognitive symptoms observed in brain-related diseases.

A Novel Prodrug Approach for Central Nervous System-Selective Estrogen Therapy

Beneficial effects of estrogens in the central nervous system (CNS) results from the synergistic combination of their well-orchestrated genomic and non-genomic actions, making them potential broad-spectrum neurotherapeutic agents. However, owing to unwanted peripheral hormonal burdens by any currently known non-invasive drug administrations, the development of estrogens as safe pharmacotherapeutic modalities cannot be realized until they are confined specifically and selectively to the site of action. We have developed small-molecule bioprecursor prodrugs carrying the para-quinol scaffold on the steroidal A-ring that are preferentially metabolized in the CNS to the corresponding estrogens. Here, we give an overview of our discovery of these prodrugs. Selected examples are shown to illustrate that, independently of the route of administrations and duration of treatments, these agents produce high concentration of estrogens only in the CNS without peripheral hormonal liability. 10β,17β-Dihydroxyestra-1,4-dien-3-one (DHED) has been the best-studied representative of this novel type of prodrugs for brain and retina health. Specific applications in preclinical animal models of centrally-regulated and estrogen-responsive human diseases, including neurodegeneration, menopausal symptoms, cognitive decline and depression, are discussed to demonstrate the translational potential of our prodrug approach for CNS-selective and gender-independent estrogen therapy with inherent therapeutic safety.

Migraine during pregnancy and in the puerperium

Pregnancy can be seen as a positive time for women migraineurs because the elevated estrogen and endogenous opioid levels raise the pain threshold and the stable hormone levels, which no longer fluctuate, eliminate a major trigger factor for the attacks. In a great majority of cases, indeed, migraine symptoms spontaneously improve throughout pregnancy. Generally, migraine without aura (MO) improves better than migraine with aura (MA), which can occur ex novo in pregnancy more frequently than MO. After childbirth, the recurrence rate of migraine attacks increases, especially during the first month; breastfeeding exerts a protective effect against the reappearance of attacks. Migraine and pregnancy share a condition of hypercoagulability; therefore, attention must be paid to the risk of cardiovascular disorders, like venous thromboembolism and ischemic or hemorrhagic strokes. Some of these diseases can be linked to preeclampsia (PE), a serious complication of pregnancy, characterized by hypertension, proteinuria, or other findings of organ failure. This condition is more common in migraineurs compared with non-migraineurs; furthermore, women whose migraines worsen during pregnancy had a 13-fold higher risk of hypertensive disorders than those in which migraine remitted or improved. Pregnancy is generally recognized to exert a beneficial effect on migraine; nonetheless, clinicians should be on the alert for possible cardiovascular complications that appear to be more frequent in this patient population.

Role of the COP9 Signalosome (CSN) in Cardiovascular Diseases

The constitutive photomorphogenesis 9 (COP9) signalosome (CSN) is an evolutionarily conserved multi-protein complex, consisting of eight subunits termed CSN1-CSN8. The main biochemical function of the CSN is the control of protein degradation via the ubiquitin-proteasome-system through regulation of cullin-RING E3-ligase (CRL) activity by deNEDDylation of cullins, but the CSN also serves as a docking platform for signaling proteins. The catalytic deNEDDylase (isopeptidase) activity of the complex is executed by CSN5, but only efficiently occurs in the three-dimensional architectural context of the complex. Due to its positioning in a central cellular pathway connected to cell responses such as cell-cycle, proliferation, and signaling, the CSN has been implicated in several human diseases, with most evidence available for a role in cancer. However, emerging evidence also suggests that the CSN is involved in inflammation and cardiovascular diseases. This is both due to its role in controlling CRLs, regulating components of key inflammatory pathways such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and complex-independent interactions of subunits such as CSN5 with inflammatory proteins. In this case, we summarize and discuss studies suggesting that the CSN may have a key role in cardiovascular diseases such as atherosclerosis and heart failure. We discuss the implicated molecular mechanisms ranging from inflammatory NF-κB signaling to proteotoxicity and necrosis, covering disease-relevant cell types such as myeloid and endothelial cells or cardiomyocytes. While the CSN is considered to be disease-exacerbating in most cancer entities, the cardiovascular studies suggest potent protective activities in the vasculature and heart. The underlying mechanisms and potential therapeutic avenues will be critically discussed.

β‑estradiol alleviates hypertension‑ and concanavalin A‑mediated inflammatory responses via modulation of connexins in peripheral blood lymphocytes

Gap junctions (GJs) formed by connexins (Cxs) in T lymphocytes have been reported to have important roles in the T lymphocyte-driven inflammatory response and hypertension-mediated inflammation. Estrogen has a protective effect on cardiovascular diseases, including hypertension and it attenuates excessive inflammatory responses in certain autoimmune diseases. However, the mechanisms involved in regulating the pro-inflammatory response are complex and poorly understood. The current study investigated whether β-estradiol suppresses hypertension and pro-inflammatory stimuli-mediated inflammatory responses by regulating Cxs and Cx-mediated GJs in peripheral blood lymphocytes. Male, 16-week-old spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) rats were randomly divided into the following three groups: WKY rats, vehicle (saline)-treated SHRs, and β-estradiol (20 µg/kg/day)-treated SHRs. β-estradiol was administered subcutaneously for 5 weeks. Hematoxylin and eosin staining was performed to evaluate target organ injury. Flow cytometry and ELISA were used to measure the populations of T lymphocyte subtypes in the peripheral blood, and expression of Cx40/Cx43 in T cell subtypes, and pro-inflammation cytokines levels, respectively. ELISA, a dye transfer technique, immunofluorescence and immunoblotting were used to analyze the effect of β-estradiol on pro-inflammatory cytokine secretion, Cx-mediated GJs and the expression of Cxs in concanavalin A (Con A)-stimulated peripheral blood lymphocytes isolated from WKY rat. β-estradiol significantly decreased blood pressure and inhibited hypertension-induced target organ injury in SHRs. Additionally, β-estradiol treatment significantly improved the immune homeostasis of SHRs, as demonstrated by the decreased percentage of cluster of differentiation (CD)4⁺/CD8⁺ T-cell subset ratio, reduced serum levels of pro-inflammatory cytokines and increased the percentage of CD4⁺CD25⁺ T cells. β-estradiol also markedly reduced the expression of Cx40/Cx43 in T lymphocytes from SHRs. In vitro, β-estradiol significantly suppressed the production of pro-inflammatory cytokines, reduced communication via Cx-mediated gap junctions and decreased the expression of Cx40/Cx43 in Con A-stimulated lymphocytes. These results indicate that β-estradiol attenuates inflammation and end organ damage in hypertension, which may be partially mediated via downregulated expression of Cxs and reduced function of Cx-mediated GJ.

The regulatory role of Toll-like receptors after ischemic stroke: neurosteroids as TLR modulators with the focus on TLR2/4

Ischemic stroke is the most common cerebrovascular disease and considered as a worldwide leading cause of death. After cerebral ischemia, different pathophysiological processes including neuroinflammation, invasion and aggregation of inflammatory cells and up-regulation of cytokines occur simultaneously. In this respect, Toll-like receptors (TLRs) are the first identified important mediators for the activation of the innate immune system and are widely expressed in glial cells and neurons following brain trauma. TLRs are also able to interact with endogenous and exogenous molecules released during ischemia and can increase tissue damage. Particularly, TLR2 and TLR4 activate different downstream inflammatory signaling pathways. In addition, TLR signaling can alternatively play a role for endogenous neuroprotection. In this review, the gene and protein structures, common genetic polymorphisms of TLR2 and TLR4, TLR-related molecular pathways and their putative role after ischemic stroke are delineated. Furthermore, the relationship between neurosteroids and TLRs as neuroprotective mechanism is highlighted in the context of brain ischemia.

Evaluating the Prognosis of Ischemic Stroke Using Low-Dose Multimodal Computed Tomography Parameters in Hyperacute Phase

PURPOSE

The aim of this study was to evaluate the potential value of low-dose multimodal computed tomography (CT) in predicting prognosis of acute ischemic stroke (AIS) within 6 hours.

METHODS

The admission "one-stop-shop" multimodal CT examination, including noncontrast CT (NCCT), low-dose CT perfusion, and CT angiography (CTA), was performed in patients with symptoms of stroke within 6 hours. Noncontrast CT, CTA source image (CTA-SI), cerebral blood flow (CBF), cerebral blood volume (CBV), time to peak (TTP), and mean transit time (MTT) maps were studied using Alberta Stroke Program Early CT Score (ASPECTS). The regional leptomeningeal collateral (rLMC) score (0-20) was dichotomized into 2 groups: good (11-20) and poor (0-10) rLMC. Poor functional outcomes were defined by a modified Rankin scale score of 3 to 6.

RESULTS

One hundred forty-four patients were ultimately selected; 43.8% of them showed poor functional outcomes. They had lower ASPECTSs on NCCT, CTA-SI, CBV, CBF, TTP, and MTT, and poor rLMC was more frequently associated with poor functional outcomes (all P < 0.001). In the multivariate analysis for AIS patients with conservative treatment, CTA-SI-ASPECTS 6 or less (odds ratio [OR], 5.9; 95% confidence interval [95% CI], 1.9-18.4; P = 0.002) and poor collaterals (OR, 5.0; 95% CI, 1.3-15.4; P = 0.017), CBV-ASPECTS 6 or less (OR, 8.0; 95% CI, 2.7-24.0; P < 0.001), CBF-ASPECTS 4 or less (OR, 8.0; 95% CI, 2.0-31.5; P = 0.003), MTT-ASPECTS≤3 (OR, 5.8; 95% CI, 1.8-18.1; P = 0.003), TTP-ASPECTS 4 or less (OR, 5.0; 95% CI, 1.6-15.1; P = 0.005), and NCCT-ASPECTS 8 or less (OR, 5.9; 95% CI, 1.7-20.4; P = 0.005) were significantly associated with poor functional outcome. In the multivariate analysis for AIS patients with thrombolysis, CTA-SI-ASPECTS 6 or less (OR, 27.5; 95% CI, 2.9-262.3; P = 0.004), poor collaterals (OR, 28.0; 95% CI, 2.8-283.0; P < 0.028), and CBV-ASPECTS 6 or less (OR, 18.0; 95% CI, 3.0-107.7; P = 0.002) were associated with poor functional outcomes. Furthermore, the area under the curve (AUC) of the combination of CTA-SI-ASPECTS 6 or less, poor collaterals, and CBV-ASPECTS 6 or less (AUC, 0.87) was greater than that for any single parameter alone: CTA-SI-ASPECTS 6 or less (AUC, 0.80; P < 0.001), poor collaterals (AUC, 0.76; P < 0.001), and CBV-ASPECTS 6 or less (AUC, 0.81; P = 0.002).

CONCLUSIONS

The combination of CTA-SI-ASPECTS, collaterals, and CBV-ASPECTS may improve predictive power compared with a single parameter alone.

Stroke and the neurovascular unit: glial cells, sex differences, and hypertension

A functional neurovascular unit (NVU) is central to meeting the brain's dynamic metabolic needs. Poststroke damage to the NVU within the ipsilateral hemisphere ranges from cell dysfunction to complete cell loss. Thus, understanding poststroke cell-cell communication within the NVU is of critical importance. Loss of coordinated NVU function exacerbates ischemic injury. However, particular cells of the NVU (e.g., astrocytes) and those with ancillary roles (e.g., microglia) also contribute to repair mechanisms. Epidemiological studies support the notion that infarct size and recovery outcomes are heterogeneous and greatly influenced by modifiable and nonmodifiable factors such as sex and the co-morbid condition common to stroke: hypertension. The mechanisms whereby sex and hypertension modulate NVU function are explored, to some extent, in preclinical laboratory studies. We present a review of the NVU in the context of ischemic stroke with a focus on glial contributions to NVU function and dysfunction. We explore the impact of sex and hypertension as modifiable and nonmodifiable risk factors and the underlying cellular mechanisms that may underlie heterogeneous stroke outcomes. Most of the preclinical investigative studies of poststroke NVU dysfunction are carried out primarily in male stroke models lacking underlying co-morbid conditions, which is very different from the human condition. As such, the evolution of translational medicine to target the NVU for improved stroke outcomes remains elusive; however, it is attainable with further research.

Sex-Dependent Effects of Bmal1-Deficiency on Mouse Cerebral Cortex Infarction in Response to Photothrombotic Stroke

Stroke is a leading cause of disability and death worldwide. There is increasing evidence that occurrence of ischemic stroke is affected by circadian system and sex. However, little is known about the effect of these factors on structural recovery after ischemic stroke. Therefore, we studied infarction in cerebral neocortex of male and female mice with deletion of the clock gene Bmal1 (Bmal1-/-) after focal ischemia induced by photothrombosis (PT). The infarct core size was significantly smaller 14 days (d) as compared to seven days after PT, consistent with structural recovery during the sub-acute phase. However, when sexes were analyzed separately 14 days after PT, infarct core was significantly larger in wild-type (Bmal1+/+) female as compared to male Bmal1+/+ mice, and in female Bmal1+/+, as compared to female Bmal1-/- mice. Volumes of reactive astrogliosis and densely packed microglia closely mirrored the size of infarct core in respective groups. Estradiol levels were significantly higher in female Bmal1-/- as compared to Bmal1+/+ mice. Our data suggests a sex-dependent effect and an interaction between sex and genotype on infarct size, the recruitment of astrocytes and microglia, and a relationship of these cells with structural recovery probably due to positive effects of estradiol during the subacute phase.

Estrogen and propofol combination therapy inhibits endoplasmic reticulum stress and remarkably attenuates cerebral ischemia-reperfusion injury and OGD injury in hippocampus

AIM

Endoplasmic reticulum stress (ERS) is vital in inducing apoptosis via caspase-12 and C/EBP homologous protein (CHOP) apoptotic pathway in the hippocampus after ischemia-reperfusion injury. The study aimed to estimate the efficacy of estrogen and propofol combination therapy against ERS-induced apoptosis after cerebral ischemia-reperfusion injury and oxygen-glucose deprivation (OGD) injury in the hippocampus in vivo and in vitro.

METHODS

Rat model of cerebral ischemia-reperfusion injury was generated by middle cerebral artery occlusion (MCAO) strategy with ischemic intervention for 90 min and reperfusion for 24 h. Propofol processing ischemia-reperfusion group (Propofol group) infused 50 mg/kg/h of propofol via the femoral vein at the onset of reperfusion for 30 min. Estrogen processing ischemia-reperfusion group (estrogen group) received 0.0125 mg/kg of estrogen via tail vein at 30 min prior to MCAO. Combination therapy for ischemia-reperfusion group (combination group) received simultaneous processing with propofol and estrogen. In vitro, brain slices were randomly exposed to dimethylsulfoxide (DSMO), 10 μm of propofol, 10 nm of estrogen, or propofol and estrogen. Changes in the orthodromic population spike (OPS) at the end of reoxygenation were recorded. Neurological deficit examination, Nissl staining, and 2,3,5-triphenyltetrazolium chloride (TTC) staining were employed to evaluate the level of cerebral ischemia-reperfusion injury. The expression of caspase-3, caspase-12, glucose-regulated protein 78 (GRP78), and CHOP were investigated by Western blot and immunofluorescence staining assays. Neural apoptotic rate in hippocampus was detected by the flow cytometry trial.

RESULTS

Neurological deficit score, infarct volume, the expression of caspase-3 (P <  0.05), caspase-12, GRP78, CHOP, and neural apoptotic rate of I/R group increased markedly (P <  0.01). When obtaining drug treatment, neurological deficit score (P <  0.05), infarct volume, the expression levels of caspase-12 and GRP78, and neural apoptotic rate of the propofol group decreased significantly (P <  0.01). Furthermore, neurological deficit score, infarct volume, expression levels of caspase-3, caspase-12, GRP78, and CHOP (P <  0.05), and neural apoptotic rate decreased in the estrogen group (P <  0.01) and especially in the combination group (P <  0.01). Compared with the propofol group, the neurological deficit score (P <  0.05), infarct volume, caspase-3, caspase-12, GRP78, CHOP, and neural apoptotic rate of the combination group decreased (P <  0.01). Compared with the estrogen group, the infarct volume, caspase-3 (P <  0.05), GRP78, CHOP, and neural apoptotic rate (P <  0.05) of the combination group decreased (P <  0.01). Compared with the propofol group, the infarct volume, caspase-3, caspase-12 (P <  0.05), and GRP78 (P <  0.05) of the estrogen group decreased (P <  0.01). Propofol and estrogen treatment can delay the abolishing time of OPS and increase the recovery rate and amplitude of OPS, compared with OGD group (P <  0.01), especially in the combination therapy (P <  0.01).

CONCLUSION

The neuroprotection of propofol and estrogen combination therapy inhibited excessive ERS-induced apoptosis against cerebral ischemia-reperfusion injury and OGD injury in the hippocampus of rats. Furthermore, the outcomes demonstrated that combination therapy yielded synergistic effects.

Estrogen, migraine, and vascular risk

Migraine has a predilection for female sex and the course of symptoms is influenced by life stage (presence of menstrual cycle, pregnancy, puerperium, menopause) and use of hormone therapy, such as hormonal contraception and hormone replacement therapy. Hormonal changes figure among common migraine triggers, especially sudden estrogen drop. Moreover, estrogens can modulate neuronal excitability, through serotonin, norepinephrine, dopamine, and endorphin regulation, and they interact with the vascular endothelium of the brain. The risk of vascular disease, and ischemic stroke in particular, is increased in women with migraine with aura (MA), but the link is unclear. One hypothesis posits for a causal association: migraine may cause clinical or subclinical brain lesions following repeated episodes of cortical spreading depression (CSD) and a second hypothesis that may explain the association between migraine and vascular diseases is the presence of common risk factors and comorbidities. Estrogens can play a differential role depending on their action on healthy or damaged endothelium, their endogenous or exogenous origin, and the duration of their treatment. Moreover, platelet activity is increased in migraineurs women, and it is further stimulated by estrogens.This review article describes the course of migraine during various life stages, with a special focus on its hormonal pathogenesis and the associated risk of vascular diseases.

Delirium is associated with increased mortality in the geriatric population

OBJECTIVE

The aim of this study was to investigate the prevalence of delirium and its association with mortality rates in elderly inpatients.

METHODS

The medical records of 1435 patients over 65 years old who were treated at a regional university hospital and were referred to the university's Consultation and Liaison Psychiatry Clinic for psychological evaluation were retrospectively analyzed. Patients with and without a diagnosis of delirium were compared. The National Survival Database was used to determine mortality rates.

RESULTS

The prevalence of delirium was 25.5%. The delirium group was older (p < .0001) and had a larger proportion of males (p < .0001). Mortality rate was higher in the delirium group at 1, 2, 3, 4, and 5 years (p < .0001 for all). Age, gender, lower urinary system diseases, chronic liver disease, solid hematologic malignancy, infections, and Alzheimer's disease emerged as significant parameters associated with mortality. Multivariate analysis of these parameters indicated that comorbid diseases (lower urinary system diseases, chronic liver disease, solid hematologic malignancy, infections, and Alzheimer's disease) are risk factors for mortality independent of demographic data such as age and gender.

CONCLUSIONS

Independent of all other factors, delirium is associated with higher mortality risk.

Elucidating sex differences in response to cerebral ischemia: immunoregulatory mechanisms and the role of microRNAs

Cerebral ischemia remains a major cause of death and disability worldwide, yet therapeutic options remain limited. Differences in sex and age play an important role in the final outcome in response to cerebral ischemia in both experimental and clinical studies: males have a higher risk and worse outcome than females at younger ages and this trend reverses in older ages. Although the molecular mechanisms underlying sex dimorphism are complex and are still not well understood, studies suggest steroid hormones, sex chromosomes, differential cell death and immune pathways, and sex-specific microRNAs may contribute to the outcome following cerebral ischemia. This review focuses on differential effects between males and females on cell death and immunological pathways in response to cerebral ischemia, the central role of innate sex differences in steroid hormone signaling, and upstreamregulation of sexually dimorphic gene expression by microRNAs.

Ischemic stroke and select adipose-derived and sex hormones: a review

Ischemic stroke is the fifth leading cause of death in the USA and is the leading cause of serious, long-term disability worldwide. The principle sex hormones (estrogen, progesterone, and testosterone), both endogenous and exogenous, have profound effects on various stroke outcomes and have become the focus of a number of studies evaluating risk factors and treatment options for ischemic stroke. In addition, the expression of other hormones that may influence stroke outcome, including select adipose-derived hormones (adiponectin, leptin, and ghrelin), can be regulated by sex hormones and are also the focus of several ischemic stroke studies. This review aims to summarize some of the preclinical and clinical studies investigating the principle sex hormones, as well as select adipose-derived hormones, as risk factors or potential treatments for ischemic stroke. In addition, the potential for relaxin, a lesser studied sex hormone, as a novel treatment option for ischemic stroke is explored.

Sex Steroids, Adult Neurogenesis, and Inflammation in CNS Homeostasis, Degeneration, and Repair

Sex steroidal hormones coordinate the development and maintenance of tissue architecture in many organs, including the central nervous systems (CNS). Within the CNS, sex steroids regulate the morphology, physiology, and behavior of a wide variety of neural cells including, but not limited to, neurons, glia, endothelial cells, and immune cells. Sex steroids spatially and temporally control distinct molecular networks, that, in turn modulate neural activity, synaptic plasticity, growth factor expression and function, nutrient exchange, cellular proliferation, and apoptosis. Over the last several decades, it has become increasingly evident that sex steroids, often in conjunction with neuroinflammation, have profound impact on the occurrence and severity of neuropsychiatric and neurodegenerative disorders. Here, I review the foundational discoveries that established the regulatory role of sex steroids in the CNS and highlight recent advances toward elucidating the complex interaction between sex steroids, neuroinflammation, and CNS regeneration through adult neurogenesis. The majority of recent work has focused on neuroinflammatory responses following acute physical damage, chronic degeneration, or pharmacological insult. Few studies directly assess the role of immune cells in regulating adult neurogenesis under healthy, homeostatic conditions. As such, I also introduce tractable, non-traditional models for examining the role of neuroimmune cells in natural neuronal turnover, seasonal plasticity of neural circuits, and extreme CNS regeneration.

Lifestyle Factors and Gender-Specific Risk of Stroke in Adults with Diabetes Mellitus: A Case-Control Study

BACKGROUND

The lifestyle interventions are effective preventive measures for stroke in general population, and the stroke risk with lifestyle factors may be modified by gender, health conditions, etc. Therefore, we conducted a case-control study to investigate the gender-specific association between stroke risk and lifestyle factors in adults with diabetes based on the China National Stroke Screening Survey.

METHODS

Structured questionnaires were used to collect demographic data and information regarding lifestyle factors, history of chronic medical conditions, and family history of stroke and the status of treatment. The case group comprised individuals diagnosed with first-ever stroke in 2013-2014 screening period. Their corresponding controls (frequency-matched for age group and urban/rural ratio) were randomly selected from individuals with diabetes without stroke.

RESULTS

There were 170 total stroke cases (500 controls) and 152 ischemic stroke cases (456 controls) among men with diabetes, and 183 total stroke cases (549 controls) and 168 ischemic stroke cases (504 controls) among women with diabetes. We found that physical inactivity was significantly associated with increased risk of total stroke (odds ratio [OR] = 1.50, 95% confidence interval [CI] 1.02-2.21) and of ischemic stroke (OR = 1.57, 95% CI 1.04-2.36) in women with diabetes. We found no significant association of smoking, overweight/obesity, or physical inactivity with risk of total or ischemic stroke in men with diabetes.

CONCLUSION

Among the lifestyle factors of smoking, overweight/obesity, and physical inactivity, physical inactivity might increase the risk of total and ischemic stroke in women with diabetes.

Estrogens as neuroprotectants: Estrogenic actions in the context of cognitive aging and brain injury

There is ample empirical evidence to support the notion that the biological impacts of estrogen extend beyond the gonads to other bodily systems, including the brain and behavior. Converging preclinical findings have indicated a neuroprotective role for estrogen in a variety of experimental models of cognitive function and brain insult. However, the surprising null or even detrimental findings of several large clinical trials evaluating the ability of estrogen-containing hormone treatments to protect against age-related brain changes and insults, including cognitive aging and brain injury, led to hesitation by both clinicians and patients in the use of exogenous estrogenic treatments for nervous system outcomes. That estrogen-containing therapies are used by tens of millions of women for a variety of health-related applications across the lifespan has made identifying conditions under which benefits with estrogen treatment will be realized an important public health issue. Here we provide a summary of the biological actions of estrogen and estrogen-containing formulations in the context of aging, cognition, stroke, and traumatic brain injury. We have devoted special attention to highlighting the notion that estrogen appears to be a conditional neuroprotectant whose efficacy is modulated by several interacting factors. By developing criteria standards for desired beneficial peripheral and neuroprotective outcomes among unique patient populations, we can optimize estrogen treatments for attenuating the consequences of, and perhaps even preventing, cognitive aging and brain injury.

Aucubin promotes angiogenesis via estrogen receptor beta in a mouse model of hindlimb ischemia

Aucubin (AU) is an iridoid glycoside that has been shown to display estrogenic properties and has various pharmacological effects. Herein, we described the angiogenic properties of AU. In the study, hindlimb ischemia was induced by ligation of femoral artery on the right leg of ovariectomized mice. AU treatment significantly accelerated perfusion recovery and reduced tissue injury in mice muscle. Quantification of CD31-positive vessels in hindlimb muscles provided evidences that AU promoted angiogenesis in peripheral ischemia. In addition, results from quantitative PCR and western blot suggested AU induced angiogenesis via vascular endothelial cell growth factor (VEGF)/Akt/endothelial nitric oxide synthase (eNOS) signaling pathway. More interestingly, AU's angiogenic effects could be completely abolished in estrogen receptor beta (ERβ) knockout mice. In conclusion, the underlying mechanisms were elucidated that AU produced pro-angiogenic effects through ERβ-mediated VEGF signaling pathways. These results expand knowledge about the beneficial effects of AU in angiogenesis and blood flow recovery. It might provide insight into the ERβ regulating neovascularisation in hindlimb ischemia and identify AU as a potent new compound used for the treatment of peripheral vascular disease.

Gender related issues in thrombosis and hemostasis

INTRODUCTION

Many aspects of hemostasis, both primary and secondary, as well as fibrinolysis display sex differences. From a clinical viewpoint, certain differential phenotypic presentations clearly arise within various disorders of thrombosis and hemostasis. Areas covered: The present mini-review summarizes selected clinical entities where sex differences are reflected in both frequency and clinical presentation of hemostasis disorders. Sex differences are discussed within the settings of cardiovascular disease, including coronary artery disease and ischemic stroke, venous thromboembolism and inherited bleeding disorders. Moreover, pregnancy and labor present particular challenges in terms of increased thromboembolic and bleeding risk, and this is also summarized. Expert commentary: Available knowledge on sex differences in risk factors and clinical presentation of disorders within thrombosis and hemostasis is increasing. However, more evidence is needed to further clarify different risk factors and treatment effect in men and women, both as regards to cardiovascular disease and venous thromboembolism. This should facilitate improved gender guided risk stratification, and prevention and treatment of these diseases. Finally, risk assessment during pregnancy remains a challenge; this applies both to thromboembolic risk assessment during normal pregnancy and special care of women with inherited bleeding disorders during labor.

Multiparity improves outcomes after cerebral ischemia in female mice despite features of increased metabovascular risk

Females show a varying degree of ischemic sensitivity throughout their lifespan, which is not fully explained by hormonal or genetic factors. Epidemiological data suggest that sex-specific life experiences such as pregnancy increase stroke risk. This work evaluated the role of parity on stroke outcome. Age-matched virgin (i.e., nulliparous) and multiparous mice were subjected to 60 min of reversible middle cerebral artery occlusion and evaluated for infarct volume, behavioral recovery, and inflammation. Using an established mating paradigm, fetal microchimeric cells present in maternal mice were also tracked after parturition and stroke. Parity was associated with sedentary behavior, weight gain, and higher triglyceride and cholesterol levels. The multiparous brain exhibited features of immune suppression, with dampened baseline microglial activity. After acute stroke, multiparous mice had smaller infarcts, less glial activation, and less behavioral impairment in the critical recovery window of 72 h. Behavioral recovery was significantly better in multiparous females compared with nulliparous mice 1 mo after stroke. This recovery was accompanied by an increase in poststroke angiogenesis that was correlated with improved performance on sensorimotor and cognitive tests. Multiparous mice had higher levels of VEGF, both at baseline and after stroke. GFP+ fetal cells were detected in the blood and migrated to areas of tissue injury where they adopted endothelial morphology 30 d after injury. Reproductive experience has profound and complex effects on neurovascular health and disease. Inclusion of female mice with reproductive experience in preclinical studies may better reflect the life-long patterning of ischemic stroke risk in women.

Sex differences in ischaemic stroke: potential cellular mechanisms

Stroke remains a leading cause of mortality and disability worldwide. More women than men have strokes each year, in part because women live longer. Women have poorer functional outcomes, are more likely to need nursing home care and have higher rates of recurrent stroke compared with men. Despite continued advancements in primary prevention, innovative acute therapies and ongoing developments in neurorehabilitation, stroke incidence and mortality continue to increase due to the aging of the U.S.

POPULATION

Sex chromosomes (XX compared with XY), sex hormones (oestrogen and androgen), epigenetic regulation and environmental factors all contribute to sex differences. Ischaemic sensitivity varies over the lifespan, with females having an "ischaemia resistant" phenotype that wanes after menopause, which has recently been modelled in the laboratory. Pharmacological therapies for acute ischaemic stroke are limited. The only pharmacological treatment for stroke approved by the Food and Drug Administration (FDA) is tissue plasminogen activator (tPA), which must be used within hours of stroke onset and has a number of contraindications. Pre-clinical studies have identified a number of potentially efficacious neuroprotective agents; however, nothing has been effectively translated into therapy in clinical practice. This may be due, in part, to the overwhelming use of young male rodents in pre-clinical research, as well as lack of sex-specific design and analysis in clinical trials. The review will summarize the current clinical evidence for sex differences in ischaemic stroke, and will discuss sex differences in the cellular mechanisms of acute ischaemic injury, highlighting cell death and immune/inflammatory pathways that may contribute to these clinical differences.

Sex differences in stroke across the lifespan: The role of T lymphocytes

Stroke is a sexually dimorphic disease. Ischemic sensitivity changes throughout the lifespan and outcomes depend largely on variables like age, sex, hormonal status, inflammation, and other existing risk factors. Immune responses after stroke play a central role in how these factors interact. Although the post-stroke immune response has been extensively studied, the contribution of lymphocytes to stroke is still not well understood. T cells participate in both innate and adaptive immune responses at both acute and chronic stages of stroke. T cell responses also change at different ages and are modulated by hormones and sex chromosome complement. T cells have also been implicated in the development of hypertension, one of the most important risk factors for vascular disease. In this review, we highlight recent literature on the lymphocytic responses to stroke in the context of age and sex, with a focus on T cell response and the interaction with important stroke risk factors.

Sex Bias in Pathogenesis of Autoimmune Neuroinflammation: Relevance for Dimethyl Fumarate Immunomodulatory/Anti-oxidant Action

In the present study, upon showing sexual dimorphism in dimethyl fumarate (DMF) efficacy to moderate the clinical severity of experimental autoimmune encephalomyelitis (EAE) in Dark Agouti rats, cellular and molecular substrate of this dimorphism was explored. In rats of both sexes, DMF administration from the day of immunization attenuated EAE severity, but this effect was more prominent in males leading to loss of the sexual dimorphism observed in vehicle-administered controls. Consistently, in male rats, DMF was more efficient in diminishing the number of CD4+ T lymphocytes infiltrating spinal cord (SC) and their reactivation, the number of IL-17+ T lymphocytes and particularly cellularity of their highly pathogenic IFN-γ+GM-CSF+IL-17+ subset. This was linked with changes in SC CD11b+CD45+TCRαβ- microglia/proinflammatory monocyte progeny, substantiated in a more prominent increase in the frequency of anti-inflammatory phygocyting CD163+ cells and the cells expressing high surface levels of immunoregulatory CD83 molecule (associated with apoptotic cells phagocytosis and implicated in downregulation of CD4+ T lymphocyte reactivation) among CD11b+CD45+TCRαβ- cells in male rat SC. These changes were associated with greater increase in the nuclear factor (erythroid-derived 2)-like 2 expression in male rats administered with DMF. In accordance with the previous findings, DMF diminished reactive nitrogen and oxygen species generation and consistently, SC level of advanced oxidation protein products, to the greater extent in male rats. Overall, our study indicates sex-specificity in the sensitivity of DMF cellular and molecular targets and encourages sex-based clinical research to define significance of sex for action of therapeutic agents moderating autoimmune neuroinflammation-/oxidative stress-related nervous tissue damage.

Inhibition of miR-181a protects female mice from transient focal cerebral ischemia by targeting astrocyte estrogen receptor-α

Whether the effect of miR-181a is sexually dimorphic in stroke is unknown. Prior work showed protection of male mice with miR-181a inhibition. Estrogen receptor-α (ERα) is an identified target of miR181 in endometrium. Therefore we investigated the separate and joint effects of miR-181a inhibition and 17β-estradiol (E2) replacement after ovariectomy. Adult female mice were ovariectomized and implanted with an E2- or vehicle-containing capsule for 14d prior to 1h middle cerebral artery occlusion (MCAO). Each group received either miR-181a antagomir or mismatch control by intracerebroventricular injection 24h before MCAO. After MCAO neurologic deficit and infarct volume were assessed. Primary male and female astrocyte cultures were subjected to glucose deprivation with miR-181a inhibitor or transfection control, and E2 or vehicle control, with/without ESRα knockdown with small interfering RNA. Cell death was assessed by propidium iodide staining, and lactate dehydrogenase assay. A miR-181a/ERα target site blocker (TSB), with/without miR-181a mimic, was used to confirm targeting of ERα by miR-181a in astrocytes. Individually, miR-181a inhibition or E2 decreased infarct volume and improved neurologic score in female mice, and protected male and female astrocyte cultures. Combined miR-181a inhibition plus E2 afforded greater protection of female mice and female astrocyte cultures, but not in male astrocyte cultures. MiR-181a inhibition only increased ERα levels in vivo and in female cultures, while ERα knockdown with siRNA increased cell death in both sexes. Treatment with ERα TSB was strongly protective in both sexes. In conclusion, the results of the present study suggest miR-181a inhibition enhances E2-mediated stroke protection in females in part by augmenting ERα production, a mechanism detected in female mice and female astrocytes. Sex differences were observed with combined miR-181a inhibition/E2 treatment, and miR-181a targeting of ERα.

Gpr124 is essential for blood-brain barrier integrity in central nervous system disease

Although blood-brain barrier (BBB) compromise is central to the etiology of diverse central nervous system (CNS) disorders, endothelial receptor proteins that control BBB function are poorly defined. The endothelial G-protein-coupled receptor (GPCR) Gpr124 has been reported to be required for normal forebrain angiogenesis and BBB function in mouse embryos, but the role of this receptor in adult animals is unknown. Here Gpr124 conditional knockout (CKO) in the endothelia of adult mice did not affect homeostatic BBB integrity, but resulted in BBB disruption and microvascular hemorrhage in mouse models of both ischemic stroke and glioblastoma, accompanied by reduced cerebrovascular canonical Wnt-β-catenin signaling. Constitutive activation of Wnt-β-catenin signaling fully corrected the BBB disruption and hemorrhage defects of Gpr124-CKO mice, with rescue of the endothelial gene tight junction, pericyte coverage and extracellular-matrix deficits. We thus identify Gpr124 as an endothelial GPCR specifically required for endothelial Wnt signaling and BBB integrity under pathological conditions in adult mice. This finding implicates Gpr124 as a potential therapeutic target for human CNS disorders characterized by BBB disruption.

Diabetes Worsens Functional Outcomes in Young Female Rats: Comparison of Stroke Models, Tissue Plasminogen Activator Effects, and Sexes

Diabetes worsens stroke outcome and increases the risk of hemorrhagic transformation (HT) after ischemic stroke, especially with tissue plasminogen activator (tPA) treatment. The widespread use of tPA is still limited by the fear of hemorrhagic transformation (HT), and underlying mechanisms are actively being pursued in preclinical studies. However, experimental models use a 10 times higher dose of tPA than the clinical dose (10 mg/kg) and mostly employ only male animals. In this translational study, we hypothesized that low-dose tPA will improve the functional recovery after the embolic stroke in both control and diabetic male and female animals. Diabetes was induced in age-matched male and female Wistar rats with high fat diet and low-dose streptozotocin (30 mg/kg, i.p.). Embolic stroke was induced with clot occlusion of the middle cerebral artery (MCA). The animals were treated with or without tPA (1 mg/kg, i.v.) at 90 min after surgery. An additional set of animals were subjected to 90 min MCAO with suture. Neurological deficits (composite score and adhesive removal test-ART), infarct size, edema ratio, and HT index were assessed 3 days after surgery. In the control groups, female rats had smaller infarcts and better functional outcomes. tPA decreased infarct size in both sexes with a greater effect in males. While there was no difference in HT between males and females without tPA, HT was less in the female + tPA group. In the diabetic groups, neuronal injury increased in females reaching that of the infarct sizes seen in male rats. tPA decreased infarct size in females but not males. HT was greater in female rats than in males and was not further increased with tPA. Diabetes worsened neurological deficits in both sexes. Male animals showed improved sensorimotor skills, especially with tPA treatment, but there was no improvement in females. These data suggest that diabetes amplifies neurovascular injury and neurological deficits in both sexes. Human dose tPA offers some degree of protection in male but not female rats. Given that control female animals experience less injury compared to male rats, the diabetes effect is more profound in females.

Sex differences in astrocyte and microglia responses immediately following middle cerebral artery occlusion in adult mice

Epidemiological studies report that infarct size is decreased and stroke outcomes are improved in young females when compared to males. However, mechanistic insight is lacking. We posit that sex-specific differences in glial cell functions occurring immediately after ischemic stroke are a source of dichotomous outcomes. In this study we assessed astrocyte Ca2+ dynamics, aquaporin 4 (AQP4) polarity, S100β expression pattern, as well as, microglia morphology and phagocytic marker CD11b in male and female mice following 60min of middle cerebral artery (MCA) occlusion. We reveal sex differences in the frequency of intracellular astrocyte Ca2+ elevations (F(1,86)=8.19, P=0.005) and microglia volume (F(1,40)=12.47, P=0.009) immediately following MCA occlusion in acute brain slices. Measured in fixed tissue, AQP4 polarity was disrupted (F(5,86)=3.30, P=0.009) and the area of non-S100β immunoreactivity increased in ipsilateral brain regions after 60min of MCA occlusion (F(5,86)=4.72, P=0.007). However, astrocyte changes were robust in male mice when compared to females. Additional sex differences were discovered regarding microglia phagocytic receptor CD11b. In sham mice, constitutively high CD11b immunofluorescence was observed in females when compared to males (P=0.03). When compared to sham, only male mice exhibited an increase in CD11b immunoreactivity after MCA occlusion (P=0.006). We posit that a sex difference in the presence of constitutive CD11b has a role in determining male and female microglia phagocytic responses to ischemia. Taken together, these findings are critical to understanding potential sex differences in glial physiology as well as stroke pathobiology which are foundational for the development of future sex-specific stroke therapies.

Multiplex immunoassay characterization and species comparison of inflammation in acute and non-acute ischemic infarcts in human and mouse brain tissue

This study provides a parallel characterization of the cytokine and chemokine response to stroke in the human and mouse brain at different stages of infarct resolution. The study goal was to address the hypothesis that chronic inflammation may contribute to stroke-related dementia. We used C57BL/6 and BALB/c mice to control for strain related differences in the mouse immune response. Our data indicate that in both mouse strains, and humans, there is increased granulocyte macrophage colony-stimulating factor (GM-CSF), interleukin-6 (IL-6), interleukin-12 p70 (IL-12p70), interferon gamma-induced protein-10 (IP-10), keratinocyte chemoattractant/interleukin-8 (KC/IL-8), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), macrophage inflammatory protein-1β (MIP-1β), regulated on activation, normal T cell expressed and secreted (RANTES), and Tumor necrosis factor-α (TNF-α) in the infarct core during the acute time period. Nevertheless, correlation and two-way ANOVA analyses reveal that despite this substantial overlap between species, there are still significant differences, particularly in the regulation of granulocyte colony-stimulating factor (G-CSF), which is increased in mice but not in humans. In the weeks after stroke, during the stage of liquefactive necrosis, there is significant resolution of the inflammatory response to stroke within the infarct. However, CD68+ macrophages remain present, and levels of IL-6 and MCP-1 remain chronically elevated in infarcts from both mice and humans. Furthermore, there is a chronic T cell response within the infarct in both species. This response is differentially polarized towards a T helper 1 (Th1) response in C57BL/6 mice, and a T helper 2 (Th2) response in BALB/c mice, suggesting that the chronic inflammatory response to stroke may follow a different trajectory in different patients. To control for the fact that the average age of the patients used in this study was 80 years, they were of both sexes, and many had suffered from multiple strokes, we also present findings that reveal how the chronic inflammatory response to stroke is impacted by age, sex, and multiple strokes in mice. Our data indicate that the chronic cytokine and chemokine response to stroke is not substantially altered in 18-month old compared to 3-month old C57BL/6 mice, although T cell infiltration is attenuated. We found a significant correlation in the chronic cytokine response to stroke in males and females. However, the chronic cytokine response to stroke was mildly exacerbated by a recurrent stroke in both C57BL/6 and BALB/c mice.

A Type A and Type D Combined Personality Typology in Essential Hypertension and Acute Coronary Syndrome Patients: Associations with Demographic, Psychological, Clinical, and Lifestyle Indicators

Many studies have focused on Type A and Type D personality types in the context of cardiovascular diseases (CVDs), but nothing is known about how these personality types combine to create new profiles. The present study aimed to develop a typology of Type A and Type D personality in two groups of patients affected by and at risk for coronary disease. The study involved 711 patients: 51.6% with acute coronary syndrome, 48.4% with essential hypertension (mean age = 56.4 years; SD = 9.7 years; 70.7% men). Cluster analysis was applied. External variables, such as socio-demographic, psychological, lifestyle, and clinical parameters, were assessed. Six groups, each with its own unique combined personality profile scores, were identified: Type D, Type A-Negatively Affected, Not Type A-Negatively Affected, Socially Inhibited-Positively Affected, Not Socially Inhibited, and Not Type A-Not Type D. The Type A-Negatively Affected cluster and, to a lesser extent, the Type D cluster, displayed the worst profile: namely higher total cardiovascular risk index, physical inactivity, higher anxiety and depression, and lower self-esteem, optimism, and health status. Identifying combined personality profiles is important in clinical research and practice in cardiovascular diseases. Practical implications are discussed.

Progress in Research on the Mechanism and Treatment of Post-stroke Infection

Post-stroke infection hinders the recovery of stroke patients and can even cause death. The main mechanism of post-stroke infection is related with the post-stroke center, the activation of the peripheral immune system, and the release of inflammatory factors caused by the lesion area and pathophysiological changes in the body. Therefore, elucidating the body’s abnormal immune inflammatory responses after stroke is crucial for the prevention, treatment, and alleviation of post-stroke infection.

Alterations in the corticotropin-releasing hormone (CRH) neurocircuitry: Insights into post stroke functional impairments

Although it is well accepted that changes in the regulation of the hypothalamic-pituitary adrenal (HPA) axis may increase susceptibility to affective disorders in the general population, this link has been less examined in stroke patients. Yet, the bidirectional association between depression and cardiovascular disease is strong, and stress increases vulnerability to stroke. Corticotropin-releasing hormone (CRH) is the central stress hormone of the HPA axis pathway and acts by binding to CRH receptors (CRHR) 1 and 2, which are located in several stress-related brain regions. Evidence from clinical and animal studies suggests a role for CRH in the neurobiological basis of depression and ischemic brain injury. Given its importance in the regulation of the neuroendocrine, autonomic, and behavioral correlates of adaptation and maladaptation to stress, CRH is likely associated in the pathophysiology of post stroke emotional impairments. The goals of this review article are to examine the clinical and experimental data describing (1) that CRH regulates the molecular signaling brain circuit underlying anxiety- and depression-like behaviors, (2) the influence of CRH and other stress markers in the pathophysiology of post stroke emotional and cognitive impairments, and (3) context and site specific interactions of CRH and BDNF as a basis for the development of novel therapeutic targets. This review addresses how the production and release of the neuropeptide CRH within the various regions of the mesocorticolimbic system influences emotional and cognitive behaviors with a look into its role in psychiatric disorders post stroke.

The Importance of Considering Sex Differences in Translational Stroke Research

Stroke is the second leading cause of death worldwide, and differences between men and women have been documented in incidence, prevalence, and outcome. Here, we reviewed the literature on sex differences in stroke severity, mortality, functional outcome, and response to therapies after ischemic stroke. Many of the sex differences in stroke severity and mortality are explained by differences in baseline demographics such as older age in women. However, women account for more stroke deaths, consistently suffer from worse stroke outcomes, and are more often institutionalized and permanently disabled than men. These sex differences in functional outcome are equalized after treatment with tissue plasminogen activator (tPA) and women may benefit more from treatment than men. However, this may depend on race, as African-American women have less of a response to tPA than other groups. Regarding endovascular treatments, the few existing studies that have investigated sex differences in stroke outcome point to equal benefit in both sexes; however, many clinical trials are relatively underpowered to detect sex differences. Further, we considered sex-specific effects in animal models of stroke and present recommendations for the performance of stroke studies in female animals. The male-biased use of research animals is distinguished from the clinical situation where there is a disproportionate and growing female stroke population. Stroke in women is greatly understudied, and including both sexes is especially important in both preclinical and clinical studies that evaluate potential stroke therapies.