Estrogen receptor-mediated resveratrol actions on blood-brain barrier of ovariectomized mice

Role of histone deacetylases and sirtuins in the ischaemic stroke: a systematic review and meta-analysis of animal studies

BACKGROUND

Treatment of ischaemic stroke requires exploration of novel neuroprotective strategies owing to the constraints of thrombolytic therapy. Recent research implies that modulation of histone deacetylases (HDAC) or sirtuins (SIRT) could be beneficial in achieving this goal.

METHODS

This systematic review and meta-analysis evaluates the effectiveness of HDAC/SIRT enzyme modulation in treating acute ischaemic stroke. It includes relevant studies but excludes human and in vitro research and non-primary studies. An electronic search was conducted across databases PubMed, Web of Science and Scopus until 20 March 2025. The methodological quality was assessed using a modified SYRCLE risk of bias tool. Infarct volume and neurological responses were extracted as key outcomes, and a random-effects meta-analysis of infarct volume was conducted for studies directly targeting HDAC/SIRT enzymes.

RESULTS

A review of 71 studies involving over 1600 animals focused on ischaemic stroke treatments, predominantly using male rodents in a transient middle cerebral artery occlusion model. Most treatments were administered intraperitoneally, starting from the inception of ischaemia until 5 days afterwards. Non-selective HDAC inhibitors and SIRT1 modulators were targeted most frequently. The meta-analysis on infarct volume with 95% CI showed an overall effect estimate of -1.529 and suggested that non-selective HDAC inhibitors exhibit the most promise in reducing infarct size. Additionally, agonists of SIRT3/7, SIRT6, SIRT1 and HDAC1, along with inhibitors of SIRT5, HDAC6 and HDAC3, may play a significant role in the treatment of ischaemic stroke. Importantly, neuroprotective treatments have been found to be most effective in reducing infarct volume when administered within 24 hours following ischaemia.

DISCUSSION

This study highlights the most promising neuroprotective trials for ischaemic stroke by focusing on infarct volume as a key outcome. However, relying exclusively on infarct volume may not fully capture the effectiveness of these treatments.

Estrogen-immuno-neuromodulation disorders in menopausal depression

A significant decrease in estrogen levels puts menopausal women at high risk for major depression, which remains difficult to cure despite its relatively clear etiology. With the discovery of abnormally elevated inflammation in menopausal depressed women, immune imbalance has become a novel focus in the study of menopausal depression. In this paper, we examined the characteristics and possible mechanisms of immune imbalance caused by decreased estrogen levels during menopause and found that estrogen deficiency disrupted immune homeostasis, especially the levels of inflammatory cytokines through the ERα/ERβ/GPER-associated NLRP3/NF-κB signaling pathways. We also analyzed the destruction of the blood-brain barrier, dysfunction of neurotransmitters, blockade of BDNF synthesis, and attenuation of neuroplasticity caused by inflammatory cytokine activity, and investigated estrogen-immuno-neuromodulation disorders in menopausal depression. Current research suggests that drugs targeting inflammatory cytokines and NLRP3/NF-κB signaling molecules are promising for restoring homeostasis of the estrogen-immuno-neuromodulation system and may play a positive role in the intervention and treatment of menopausal depression.

Sex, hormones and cerebrovascular function: from development to disorder

Proper cerebrovascular development and neurogliovascular unit assembly are essential for brain growth and function throughout life, ensuring the continuous supply of nutrients and oxygen. This involves crucial events during pre- and postnatal stages through key pathways, including vascular endothelial growth factor (VEGF) and Wnt signaling. These pathways are pivotal for brain vascular growth, expansion, and blood-brain barrier (BBB) maturation. Interestingly, during fetal and neonatal life, cerebrovascular formation coincides with the early peak activity of the hypothalamic-pituitary-gonadal axis, supporting the idea of sex hormonal influence on cerebrovascular development and barriergenesis.Sex hormonal dysregulation in early development has been implicated in neurodevelopmental disorders with highly sexually dimorphic features, such as autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD). Both disorders show higher prevalence in men, with varying symptoms between sexes, with boys exhibiting more externalizing behaviors, such as aggressivity or hyperactivity, and girls displaying higher internalizing behaviors, including anxiety, depression, or attention disorders. Indeed, ASD and ADHD are linked to high prenatal testosterone exposure and reduced aromatase expression, potentially explaining sex differences in prevalence and symptomatology. In line with this, high estrogen levels seem to attenuate ADHD symptoms. At the cerebrovascular level, sex- and region-specific variations of cerebral blood flow perfusion have been reported in both conditions, indicating an impact of gonadal hormones on the brain vascular system, disrupting its ability to respond to neuronal demands.This review aims to provide an overview of the existing knowledge concerning the impact of sex hormones on cerebrovascular formation and maturation, as well as the onset of neurodevelopmental disorders. Here, we explore the concept of gonadal hormone interactions with brain vascular and BBB development to function, with a particular focus on the modulation of VEGF and Wnt signaling. We outline how these pathways may be involved in the underpinnings of ASD and ADHD. Outstanding questions and potential avenues for future research are highlighted, as uncovering sex-specific physiological and pathological aspects of brain vascular development might lead to innovative therapeutic approaches in the context of ASD, ADHD and beyond.

Estrogen receptor-mediated health benefits of phytochemicals: a review

Estrogen receptors (ERs) are transcription factors with two subtypes: estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), which are essential for the maintenance of human health and play a regulatory role in common diseases such as breast cancer, osteoporosis, neurodegenerative disorders, liver injuries and lung cancers. A number of phytochemicals extracted from various fruits and vegetables have been demonstrated to exhibit estrogenic effects and are termed phytoestrogens. As modulators of ERs, phytoestrogens can be involved in the prevention and treatment of multiple diseases as complementary or alternative therapeutic agents and have a variety of health benefits for humans. This article reviews the health benefits of phytoestrogens in clinical and epidemiologic studies for several diseases and also provides a detailed description of the molecular mechanisms of their action. A brief comparison of the advantages and disadvantages of natural phytochemicals compared to synthetic drugs is also presented. The role of phytoestrogens in the treatment of diseases and human health requires further research to fully realize their therapeutic potential.

Resveratrol: a potential medication for the prevention and treatment of varicella zoster virus-induced ischemic stroke

BACKGROUND

Infection rate of varicella zoster virus (VZV) is 95% in humans, and VZV infection is strongly associated with ischemic stroke (IS). However, the underlying molecular mechanisms of VZV-induced IS are still unclear, and there are no effective agents to treat and prevent VZV-induced IS.

OBJECTIVE

By integrating bioinformatics, this study explored the interactions between VZV and IS and potential medication to treat and prevent VZV-induced IS.

METHODS

In this study, the VZV and IS datasets from the GEO database were used to specify the common genes. Then, bioinformatics analysis including Gene Ontology, Kyoto Encyclopedia Genes Genomes and Protein-Protein Interaction network analysis was performed. Further, the hub genes, transcription factor (TF) gene interactions, TF-miRNA co-regulatory network and potential drug were obtained. Finally, validation was performed using molecular docking and molecular dynamics simulations.

RESULTS

The potential molecular mechanisms of VZV-induced IS were studied using multiple bioinformatics tools. Ten hub genes were COL1A2, DCN, PDGFRB, ACTA2, etc. TF genes and miRNAs included JUN, FOS, CREB, BRCA1, PPARG, STAT3, miR-29, etc. A series of mechanism may be involved, such as inflammation, oxidative stress, blood-brain barrier disruption, foam cell generation and among others. Finally, we proposed resveratrol as a potential therapeutic medicine for the prevention and treatment of VZV-induced IS. Molecular docking and molecular dynamics results showed that resveratrol and hub genes exhibited strong binding score.

CONCLUSIONS

Resveratrol could be an alternative for the prevention and treatment of VZV-IS. More in vivo and in vitro studies are needed in the future to fully explore the molecular mechanisms between VZV and IS and for medication development.

Experimental Models of In Vitro Blood-Brain Barrier for CNS Drug Delivery: An Evolutionary Perspective

Central nervous system (CNS) disorders represent one of the leading causes of global health burden. Nonetheless, new therapies approved against these disorders are among the lowest compared to their counterparts. The absence of reliable and efficient in vitro blood-brain barrier (BBB) models resembling in vivo barrier properties stands out as a significant roadblock in developing successful therapy for CNS disorders. Therefore, advancement in the creation of robust and sensitive in vitro BBB models for drug screening might allow us to expedite neurological drug development. This review discusses the major in vitro BBB models developed as of now for exploring the barrier properties of the cerebral vasculature. Our main focus is describing existing in vitro models, including the 2D transwell models covering both single-layer and co-culture models, 3D organoid models, and microfluidic models with their construction, permeability measurement, applications, and limitations. Although microfluidic models are better at recapitulating the in vivo properties of BBB than other models, significant gaps still exist for their use in predicting the performance of neurotherapeutics. However, this comprehensive account of in vitro BBB models can be useful for researchers to create improved models in the future.

Neurovascular Dysfunction in Diverse Communities With Health Disparities-Contributions to Dementia and Alzheimer's Disease

Alzheimer's disease and related dementias (ADRD) are an expanding worldwide crisis. In the absence of scientific breakthroughs, the global prevalence of ADRD will continue to increase as more people are living longer. Racial or ethnic minority groups have an increased risk and incidence of ADRD and have often been neglected by the scientific research community. There is mounting evidence that vascular insults in the brain can initiate a series of biological events leading to neurodegeneration, cognitive impairment, and ADRD. We are a group of researchers interested in developing and expanding ADRD research, with an emphasis on vascular contributions to dementia, to serve our local diverse community. Toward this goal, the primary objective of this review was to investigate and better understand health disparities in Alabama and the contributions of the social determinants of health to those disparities, particularly in the context of vascular dysfunction in ADRD. Here, we explain the neurovascular dysfunction associated with Alzheimer's disease (AD) as well as the intrinsic and extrinsic risk factors contributing to dysfunction of the neurovascular unit (NVU). Next, we ascertain ethnoregional health disparities of individuals living in Alabama, as well as relevant vascular risk factors linked to AD. We also discuss current pharmaceutical and non-pharmaceutical treatment options for neurovascular dysfunction, mild cognitive impairment (MCI) and AD, including relevant studies and ongoing clinical trials. Overall, individuals in Alabama are adversely affected by social and structural determinants of health leading to health disparities, driven by rurality, ethnic minority status, and lower socioeconomic status (SES). In general, these communities have limited access to healthcare and healthy food and other amenities resulting in decreased opportunities for early diagnosis of and pharmaceutical treatments for ADRD. Although this review is focused on the current state of health disparities of ADRD patients in Alabama, future studies must include diversity of race, ethnicity, and region to best be able to treat all individuals affected by ADRD.

Lithium therapy subdues neuroinflammation to maintain pyramidal cells arborization and rescues neurobehavioural impairments in ovariectomized rats

Oestrogen deprivation as a consequence of menopause alters the brain neuronal circuit and results in the development of neurobehavioural symptoms later. Hormone replacement therapy to some extent helps to overcome these abnormalities but is associated with various adverse events. Lithium therapy is being used to manage multiple neuropsychiatric disorders and is reported to maintain structural synaptic plasticity, suppress neuroinflammation, and promote adult neurogenesis. The present study examined the effect of lithium treatment on the neurobehavioural impairments in ovariectomized rat model mimicking clinical postmenopausal condition. A protective effect of lithium treatment was observed on the reconsolidation of spatial and recognition memory along with depression-like behaviour in ovariectomized rats. The Golgi-Cox staining revealed increased dendritic length and spine density in the pyramidal neurons of the CA1 region of the hippocampus, layer V of the somatosensory cortex, and layer II/III of the prefrontal cortex in the treated group. A significant reduction in pro-inflammatory markers, Il2, II6, and Il1b, was observed in the hippocampus, somatosensory cortex, and prefrontal cortex following lithium treatment. mRNA expression studies of Gfap and Pparg, along with histopathological analysis, suggested reactive astrogliosis to be a major contributor of neuroinflammation in ovariectomized rats that was normalized following lithium treatment. Further, the treatment inhibited Gsk-3β activity and maintained the normal level of β-catenin, CREB, and BDNF. The results revealed a defensive role of lithium against ovariectomy-induced neurobehavioural impairments, thus suggesting it to be a potential therapeutic agent for managing postmenopausal neurological symptoms.

Drug Penetration into the Central Nervous System: Pharmacokinetic Concepts and In Vitro Model Systems

Delivery of most drugs into the central nervous system (CNS) is restricted by the blood-brain barrier (BBB), which remains a significant bottleneck for development of novel CNS-targeted therapeutics or molecular tracers for neuroimaging. Consistent failure to reliably predict drug efficiency based on single measures for the rate or extent of brain penetration has led to the emergence of a more holistic framework that integrates data from various in vivo, in situ and in vitro assays to obtain a comprehensive description of drug delivery to and distribution within the brain. Coupled with ongoing development of suitable in vitro BBB models, this integrated approach promises to reduce the incidence of costly late-stage failures in CNS drug development, and could help to overcome some of the technical, economic and ethical issues associated with in vivo studies in animal models. Here, we provide an overview of BBB structure and function in vivo, and a summary of the pharmacokinetic parameters that can be used to determine and predict the rate and extent of drug penetration into the brain. We also review different in vitro models with regard to their inherent shortcomings and potential usefulness for development of fast-acting drugs or neurotracers labeled with short-lived radionuclides. In this regard, a special focus has been set on those systems that are sufficiently well established to be used in laboratories without significant bioengineering expertise.

Resveratrol Attenuates Meningitic Escherichia coli-Mediated Blood-Brain Barrier Disruption

Meningitic Escherichia coli can infiltrate the central nervous system (CNS), consequently increasing the levels of proinflammatory cytokines and chemokines and deteriorating the integrity of the blood-brain barrier (BBB). Resveratrol has emerged in recent years as a compound with antioxidant and anti-inflammatory properties. However, it is still unknown how resveratrol affects meningitic E. coli-induced CNS dysfunction. Here, by using in vivo and in vitro BBB models, we demonstrated that resveratrol treatment significantly inhibited meningitic E. coli invasion of the BBB, protected the integrity of the BBB, and reduced neuroinflammation and lethality. In mechanism, resveratrol inhibited bacterial penetration of the BBB by attenuating the upregulation of caveolin-1 (CAV-1), a class of lipid rafts maintaining endothelial cell function. Resveratrol treatment also maintained BBB permeability by suppressing the ERK1/2-VEGFA signaling cascade. In vivo treatment of resveratrol decreased the production of inflammatory cytokines and improved the survival rate in mice challenged with meningitic E. coli. These findings collectively indicated that resveratrol could attenuate meningitic E. coli-induced CNS injury, which might constitute a new approach for future prevention and treatment of E. coli meningitis.

Enhanced repair processes and iron uptake by ischemic preconditioning in the brain during the recovery phase after ischemic stroke

Ischemic preconditioning (IP) reduces brain damage after subsequent ischemic strokes by activating endogenous protective mechanisms in rodents. Transient ischemic attack (TIA) induces tolerance in the human brain after ischemic strokes; defining mechanisms of IP effects may provide therapeutic targets to improve recovery of patients with ischemic strokes. Iron transported across the blood-brain barrier (BBB) is required for brain functions, including myelination, and its levels should be finely regulated to avoid harmful effects. This study aimed to determine whether IP enhances repair processes by modulating iron metabolism during the post-stroke chronic phase. Male mice were divided into sham and IP groups, and IP was induced 24 h before a transient focal ischemic stroke. Sensorimotor recovery was observed over 8 weeks after the stroke, and brain volumes and levels of proteins related to repair processes and iron metabolism in the ischemic brains were examined 8 weeks after the stroke. There was significantly less ischemic brain atrophy in the IP group than in the sham group, with no differences in sensorimotor recovery between the groups. Levels of tight junction proteins of BBB, neurites outgrowth markers, and myelin sheath proteins and markers for mature oligodendrocytes were significantly increased in the IP group. Iron import proteins, transferrin receptor 1 and DMT1, were also increased in the IP group. These results indicate that IP increases brain repair processes and iron uptake during the chronic phase after an ischemic stroke, and provide new insights to understand the molecular mechanisms of TIA effects on post-stroke recovery.

Shuxuetong injection protects cerebral microvascular endothelial cells against oxygen-glucose deprivation reperfusion

Shuxuetong injection composed of leech (Hirudo nipponica Whitman) and earthworm (Pheretima aspergillum) has been used for the clinical treatment of acute stroke for many years in China. However, the precise neuroprotective mechanism of Shuxuetong injection remains poorly understood. Here, cerebral microvascular endothelial cells (bEnd.3) were incubated in glucose-free Dulbecco’s modified Eagle’s medium containing 95% N₂/5% CO₂ for 6 hours, followed by high-glucose medium containing 95% O₂ and 5% CO₂ for 18 hours to establish an oxygen-glucose deprivation/reperfusion model. This in vitro cell model was administered Shuxuetong injection at 1/32, 1/64, and 1/128 concentrations (diluted 32-, 64-, and 128-times). Cell Counting Kit-8 assay was used to evaluate cell viability. A fluorescence method was used to measure lactate dehydrogenase, and a fluorescence microplate reader used to detect intracellular reactive oxygen species. A fluorescent probe was also used to measure mitochondrial superoxide production. A cell resistance meter was used to measure transepithelial resistance and examine integrity of monolayer cells. The fluorescein isothiocyanate-dextran test was performed to examine blood-brain barrier permeability. Real-time reverse transcription polymerase chain reaction was performed to analyze mRNA expression levels of tumor necrosis factor alpha, interleukin-1β, interleukin-6, and inducible nitric oxide synthase. Western blot assay was performed to analyze expression of caspase-3, intercellular adhesion molecule 1, vascular cell adhesion molecule 1, occludin, vascular endothelial growth factor, cleaved caspase-3, B-cell lymphoma 2, phosphorylated extracellular signal-regulated protein kinase, extracellular signal-regulated protein kinase, nuclear factor-κB p65, I kappa B alpha, phosphorylated I kappa B alpha, I kappa B kinase, phosphorylated I kappa B kinase, claudin-5, and zonula occludens-1. Our results show that Shuxuetong injection increases bEnd.3 cell viability and B-cell lymphoma 2 expression, reduces cleaved caspase-3 expression, inhibits production of reactive oxygen species and mitochondrial superoxide, suppresses expression of tumor necrosis factor alpha, interleukin-1β, interleukin-6, inducible nitric oxide synthase mRNA, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1, markedly increases transepithelial resistance, decreases blood-brain barrier permeability, upregulates claudin-5, occludin, and zonula occludens-1 expression, reduces nuclear factor-κB p65 and vascular endothelial growth factor expression, and reduces I kappa B alpha, extracellular signal-regulated protein kinase 1/2, and I kappa B kinase phosphorylation levels. Overall, these findings suggest that Shuxuetong injection has protective effects on brain microvascular endothelial cells after oxygen-glucose deprivation/reperfusion. Moreover, its protective effect is associated with reduction of mitochondrial superoxide production, inhibition of the inflammatory response, and inhibition of vascular endothelial growth factor, extracellular signal-regulated protein kinase 1/2, and the nuclear factor-κB p65 signaling pathway.

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.

The novel estrogenic receptor GPR30 alleviates ischemic injury by inhibiting TLR4-mediated microglial inflammation

Background

The steroid hormone estrogen (17-β-estradiol, E2) provides neuroprotection against cerebral ischemic injury by activating estrogen receptors. The novel estrogen receptor G protein-coupled receptor 30 (GPR30) is highly expressed in the brain and provides acute neuroprotection against stroke. However, the underlying mechanisms remain unclear.

Methods

In this study, ovariectomized female mice were subjected to middle cerebral artery occlusion (MCAO), and E2, G1, and ICI182780 were administered immediately upon reperfusion. The infarction volume, neurological scores, and neuronal injuries were examined. Primary microglial cells were subjected to oxygen-glucose deprivation (OGD), and the drugs were administered immediately upon reintroduction. The pro-inflammatory cytokines TNF-α, IL-1β, and IL-6 in penumbra and microglia were assessed by ELISA. The cell viability and lactose dehydrogenase (LDH) release of neurons co-cultured with microglia were analyzed using cell counting kit-8 (CCK8) and LDH release assays. Microglial activation as well as GPR30, Iba1, and Toll-like receptor 4 (TLR4) protein expression and TLR4 mRNA expression were detected. Additionally, NF-κB activity was detected in lipopolysaccharide (LPS)-activated microglia after the activation of GPR30.

Results

GPR30 was highly expressed in microglia and significantly increased after ischemic injury. The activation of GPR30 significantly reduced the infarction volume, improved the neurological deficit, and alleviated neuronal injuries. Moreover, GPR30 activation significantly reduced the release of TNF-α, IL-1β, and IL-6 from ischemic penumbra and microglia subjected to OGD and alleviated neuronal injury as assessed using the CCK8 and LDH assays. Finally, the activation of GPR30 relieved microglial activation, reduced Iba1 and TLR4 protein expression and TLR4 mRNA levels, and inhibited NF-κB activity.

Conclusions

Microglial GPR30 exerts acute neuroprotective effects by inhibiting TLR4-mediated microglial inflammation, which indicates that GPR30 may be a potential target for the treatment of ischemic stroke.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1246-x) contains supplementary material, which is available to authorized users.

Repression of adenosine triphosphate-binding cassette transporter ABCG2 by estrogen increases intracellular glutathione in brain endothelial cells following ischemic reperfusion injury

The adenosine triphosphate-binding cassette efflux transporter ABCG2, which is located in the blood-brain barrier limits the entry of endogenous compounds and xenobiotics into the brain, and its expression and activity are regulated by estrogen. This study was aimed to define the role of ABCG2 in estrogen-mediated neuroprotection against ischemic injury. ABCG2 protein levels before and after ischemic stroke were increased in the brain of female mice by ovariectomy, which were reversed by estrogen replacement. In brain endothelial cell line bEnd.3, estrogen reduced the basal ABCG2 protein level and efflux activity and protected cells from ischemic injury without inducing ABCG2 expression. When bEnd.3 cells were transfected with ABCG2 small interfering RNA, ischemia-induced cell death was reduced, and the intracellular concentration of glutathione, an antioxidant that is transported by ABCG2, was increased. In addition, after ischemic stroke in ovariectomized mice, estrogen prevented the reduction of intracellular glutathione level in brain microvessels. These data suggested that the suppression of ABCG2 by estrogen is involved in neuroprotection against ischemic injury by increasing intracellular glutathione, and that the modulation of ABCG2 activity offers a therapeutic target for brain diseases in estrogen-deficient aged women.

Rutin attenuates cerebral ischemia-reperfusion injury in ovariectomized rats via estrogen-receptor-mediated BDNF-TrkB and NGF-TrkA signaling

Rutin, a flavonoid glycoside, has been reported to exert neuroprotective effects. Loss of endogenous estrogen and dysregulation of the estrogen receptor (ER) signaling pathway are associated with the increased risk of stroke in women after menopause. This study was performed to investigate whether rutin could protect against cerebral ischemia by modulating the ER pathway. Ovariectomized (OVX) rats were given intraperitoneal injections of vehicle (dimethyl sulfoxide), rutin (100 mg/kg body mass) or 17β-estradiol (100 μg/kg body mass) for 5 consecutive days. Then, the rats were subjected to middle cerebral artery occlusion (MCAO) for 1 h followed by a 24 h reperfusion to establish the cerebral ischemia-reperfusion (I/R) injury. We found that rutin improved the sensorimotor performance and recognition memory of rats subjected to I/R, decreased the infarct size, and attenuated neuron loss. Rutin treatment also increased the levels of ERα, ERβ, brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), tropomyosin receptor kinase A (TrkA), TrkB, and phospho-cAMP-responsive element binding protein (p-CREB) in rat hippocampus and cerebral cortex. The protective effects of rutin were comparable to that of 17β-estradiol, and were partially blocked by ICI182780, an ER antagonist. The above results suggest that rutin preconditioning ameliorates cerebral I/R injury in OVX rats through ER-mediated BDNF-TrkB and NGF-TrkA signaling.

Protective role of resveratrol on testicular germ cells in mice with testicular toxicity

Objective

The aim of the present study was to investigate the possible beneficial effects of resveratrol in mice subjected to vinyl cyclohexene dieposide (VCD) -induced testicular toxicity.

Material and methods

A total of thirty- six Swiss albino male mice aged 28-days were used in the present study. The study was composed of two stages where mice which received or did not receive VCD (320 mg/kg/day) were administered resveratrol. The animals were assigned into control and resveratrol-treated groups in the first stage and into groups of VCD- and VCD+resveratrol-treated groups in the second stage. At the end of the experiments, relative testicular weight (TW/BW) and dry/wet weight of testis (TDW/TWW) were calculated. Histological analysis by hematoxylin and eosin (H&E) staining and immunohistochemical staining by BAX and Bcl-2 were performed. Serum testosterone, LH and FSH levels were measured by a commercially available ELISA kit.

Results

Resveratrol caused a dose-dependent increase in TW/BW and decrease in TDW/TWW (p<0.05). Resveratrol at a dose of 20 mg/kg resulted in an improvement in testosterone, LH and FSH levels in mice with VCD-induced testicular toxicity (p<0.001). Resveratrol also improved apoptotic index and epithelial cell height of testicular seminipherous tubuli significantly after VCD exposure (p<0.001).

Conclusion

Results of the present study suggest that resveratrol can be used as a protective and/or therapeutic agent particularly for cases with male infertility caused by testicular toxicity.

Increased ventilation in female erythropoietin-deficient mouse line is not progesterone and estrous stage-dependent

Previous studies suggest that chronic erythropoietin (Epo) deficiency in male mice does not alter normoxic/hypoxic ventilation. As effects of Epo are sex specific and as progesterone could be a respiratory stimulant, we evaluated the impact of Epo deficiency and its possible interaction with progesterone in ventilatory control in female mice during estrous cycle phases. Compared to wild type (WT) animals, Epo-TAg^h female mice exhibited higher ventilation in hypoxia. However, when data were separated into luteal and follicular phases of the estrous cycle, basal ventilation and hypoxic ventilation were not different in both mice strains. As progesterone is known to be a potent respiratory stimulant, additional experiments were performed to elucidate its role. Interestingly, after mifepristone treatment, HVR was not modified in WT and Epo-TAg^h mice, showing that the ventilatory stimulation observed in females was not directly mediated by progesterone. We conclude that Epo-TAg^h female mice show no estrous stage-dependent increase of ventilatory control and progesterone independent response to hypoxia.

Differential Effects of Resveratrol on the Expression of Brain-Derived Neurotrophic Factor Transcripts and Protein in the Hippocampus of Rat Brain

BACKGROUND

The induction of brain-derived neurotrophic factor (BDNF) expression in the hippocampus has shown to play a role in the beneficial effects of resveratrol (RSV) on the learning and memory. The BDNF gene has a complicated structure with eight 5' noncoding exons (I-IXa), each of which can splice to a common coding exon (IX) to form a functional transcript. Estrogens increase levels of BDNF transcripts in the hippocampus of rats. The aim of this study was to evaluate the effects of the phytoestrogen, RSV, on the splicing pattern of BDNF transcripts and on the pro-BDNF protein in the hippocampi of mother rats and their embryos.

METHODS

RSV (60 or 120 mg/kg BW/day) was administered orally to pregnant rats from days 1 to 20 of gestation. Hippocampi of adults and embryos were dissected 24 h after the last administration of RSV. Extracts from hippocampi were subject to quantitative (q) RT-PCR and Western blotting to assess splicing pattern of the BDNF transcripts and levels of pro-BDNF protein, respectively.

RESULTS

RSV (120 mg/kg BW/day) caused a statistically significant increase in the expression levels of BDNF exons III, IV and IX, but not the exon I in the hippocampi of adult rats (P≤0.05). Levels of pro-BDNF protein remained unchanged in the hippocampal tissues from both adult and embryonic rats treated by RSV (60 or 120 mg/kg BW/day).

CONCLUSION

Our results showed that RSV differentially activates promoters of the BDNF gene in the hippocampus of pregnant rats, but fails to affect the pro-BDNF level neither in adult nor in the embryonic hippocampal tissues.

New experimental models of the blood-brain barrier for CNS drug discovery

INTRODUCTION

The blood-brain barrier (BBB) is a dynamic biological interface which actively controls the passage of substances between the blood and the central nervous system (CNS). From a biological and functional standpoint, the BBB plays a crucial role in maintaining brain homeostasis inasmuch that deterioration of BBB functions are prodromal to many CNS disorders. Conversely, the BBB hinders the delivery of drugs targeting the brain to treat a variety of neurological diseases. Area covered: This article reviews recent technological improvements and innovation in the field of BBB modeling including static and dynamic cell-based platforms, microfluidic systems and the use of stem cells and 3D printing technologies. Additionally, the authors laid out a roadmap for the integration of microfluidics and stem cell biology as a holistic approach for the development of novel in vitro BBB platforms. Expert opinion: Development of effective CNS drugs has been hindered by the lack of reliable strategies to mimic the BBB and cerebrovascular impairments in vitro. Technological advancements in BBB modeling have fostered the development of highly integrative and quasi- physiological in vitro platforms to support the process of drug discovery. These advanced in vitro tools are likely to further current understanding of the cerebrovascular modulatory mechanisms.

Resveratrol protects the ovary against chromium-toxicity by enhancing endogenous antioxidant enzymes and inhibiting metabolic clearance of estradiol

Resveratrol (RVT), a polyphenolic component in grapes and red wine, has been known for its cytoprotective actions against several diseases. However, beneficial effects of RVT against early exposure to endocrine disrupting chemicals (EDCs) have not been understood. EDCs are linked to several ovarian diseases such as premature ovarian failure, polycystic ovary syndrome, early menopause and infertility in women. Hexavalent chromium (CrVI) is a heavy metal EDC, and widely used in >50 industries. Environmental contamination with CrVI in the US is rapidly increasing, predisposing the human to several illnesses including cancers and still birth. Our lab has been involved in determining the molecular mechanism of CrVI-induced female infertility and intervention strategies to mitigate CrVI effects. Lactating mother rats were exposed to CrVI (50ppm potassium dichromate) from postpartum days 1-21 through drinking water with or without RVT (10mg/kg body wt., through oral gavage daily). During this time, F1 females received respective treatments through mother's milk. On postnatal day (PND) 25, blood and the ovary, kidney and liver were collected from the F1 females for analyses. CrVI increased atresia of follicles by increasing cytochrome C and cleaved caspase-3; decreasing antiapoptotic proteins; decreasing estradiol (E2) biosynthesis and enhancing metabolic clearance of E2, increasing oxidative stress and decreasing endogenous antioxidants. RVT mitigated the effects of CrVI by upregulating cell survival proteins and AOXs; and restored E2 levels by inhibiting hydroxylation, glucuronidation and sulphation of E2. This is the first study to report the protective effects of RVT against any toxicant in the ovary.

Neurovascular dysfunction and neurodegeneration in dementia and Alzheimer's disease

Vascular insults can initiate a cascade of molecular events leading to neurodegeneration, cognitive impairment, and dementia. Here, we review the cellular and molecular mechanisms in cerebral blood vessels and the pathophysiological events leading to cerebral blood flow dysregulation and disruption of the neurovascular unit and the blood-brain barrier, which all may contribute to the onset and progression of dementia and Alzheimer's disease (AD). Particularly, we examine the link between neurovascular dysfunction and neurodegeneration including the effects of AD genetic risk factors on cerebrovascular functions and clearance of Alzheimer's amyloid-β peptide toxin, and the impact of vascular risk factors, environment, and lifestyle on cerebral blood vessels, which in turn may affect synaptic, neuronal, and cognitive functions. Finally, we examine potential experimental treatments for dementia and AD based on the neurovascular model, and discuss some critical questions to be addressed by future studies. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock.

Resveratrol attenuates peripheral and brain inflammation and reduces ischemic brain injury in aged female mice

Resveratrol is known to improve metabolic dysfunction associated with obesity. Visceral obesity is a sign of aging and is considered a risk factor for ischemic stroke. In this study, we investigated the effects of resveratrol on inflammation in visceral adipose tissue and the brain and its effects on ischemic brain injury in aged female mice. Mice treated with resveratrol (0.1 mg/kg, p.o.) for 10 days showed reduced levels of interleukin-1β and tumor necrosis factor-α, as well as a reduction in the size of adipocytes in visceral adipose tissue. Resveratrol also reduced interleukin-1β and tumor necrosis factor-α protein levels and immunoglobulin G extravasation in the brain. Mice treated with resveratrol demonstrated smaller infarct size, improved neurological function, and blunted peripheral inflammation at 3 days postischemic stroke. These results showed that resveratrol counteracted inflammation in visceral adipose tissue and in the brain and reduced stroke-induced brain injury and peripheral inflammation in aged female mice. Therefore, resveratrol administration can be a valuable strategy for the prevention of age-associated and disease-provoked inflammation in postmenopausal women.

Activation of classical estrogen receptor subtypes reduces tight junction disruption of brain endothelial cells under ischemia/reperfusion injury

Ischemic stroke, which induces oxidative stress in the brain, disrupts tight junctions (TJs) between brain endothelial cells, resulting in blood-brain barrier (BBB) breakdown and brain edema. Estrogen reduces oxidative stress and protects brain endothelial cells from ischemic insult. The aim of this study was to determine the protective effects of estrogen on TJ disruption and to examine the roles of classical estrogen receptor (ER) subtypes, ERα- and ERβ, in estrogen effects in brain endothelial cells (bEnd.3) exposed to oxygen-glucose deprivation/reperfusion (OGD/R) injury. Estrogen pretreatment prevented OGD/R-induced decreases in cell viability and TJ protein levels. ERα- and ERβ-specific agonists also reduced TJ disruption. Knockdown of ERα or ERβ expression partially inhibited the effects of estrogen, but completely reversed the effects of corresponding ER subtype-specific agonists on the outcomes of OGD/R. During the early reperfusion period, activation of extracellular signal-regulated kinase1/2 and hypoxia-inducible factor 1α/vascular endothelial growth factor was associated with decreased expression of occludin and claudin-5, respectively, and these changes in TJ protein levels were differentially regulated by ER subtype-specific agonists. Our results suggest that ERα and ERβ activation reduce TJ disruption via inhibition of signaling molecules after ischemic injury and that targeting each ER subtype can be a useful strategy for protecting the BBB from ischemic stroke in postmenopausal women.

Gender Differences in the Neurobiology of Anxiety: Focus on Adult Hippocampal Neurogenesis

Although the literature reports a higher incidence of anxiety disorders in women, the majority of basic research has focused on male rodents, thus resulting in a lack of knowledge on the neurobiology of anxiety in females. Bridging this gap is crucial for the design of effective translational interventions in women. One of the key brain mechanisms likely to regulate anxious behavior is adult hippocampal neurogenesis (AHN). This review paper aims to discuss the evidence on the differences between male and female rodents with regard to anxiety-related behavior and physiology, with a special focus on AHN. The differences between male and female physiologies are greatly influenced by hormonal differences. Gonadal hormones and their fluctuations during the estrous cycle have often been identified as agents responsible for sexual dimorphism in behavior and AHN. During sexual maturity, hormone levels fluctuate cyclically in females more than in males, increasing the stress response and the susceptibility to anxiety. It is therefore of great importance that future research investigates anxiety and other neurophysiological aspects in the female model, so that results can be more accurately applicable to the female population.

Resveratrol neuroprotection in stroke and traumatic CNS injury

Resveratrol, a stilbene formed in many plants in response to various stressors, elicits multiple beneficial effects in vertebrates. Particularly, resveratrol was shown to have therapeutic properties in cancer, atherosclerosis and neurodegeneration. Resveratrol-induced benefits are modulated by multiple synergistic pathways that control oxidative stress, inflammation and cell death. Despite the lack of a definitive mechanism, both in vivo and in vitro studies suggest that resveratrol can induce a neuroprotective state when administered acutely or prior to experimental injury to the CNS. In this review, we discuss the neuroprotective potential of resveratrol in stroke, traumatic brain injury and spinal cord injury, with a focus on the molecular pathways responsible for this protection.

Progesterone attenuates thrombin-induced endothelial barrier disruption in the brain endothelial cell line bEnd.3: The role of tight junction proteins and the endothelial protein C receptor

This study examines the effects of progesterone on blood-brain barrier (BBB) integrity following thrombin administration. Thrombin is expressed in many diseases which affect neural tissue and is associated with breakdown of the BBB. Progesterone has shown protective effects on the BBB in stroke and traumatic brain injury.

METHODS

Mouse brain endothelial (bEnd.3) cells were treated with progesterone (20 μmol/l) for 24h before thrombin administration (60 U/ml). BBB permeability was measured by transendothelial electrical resistance (TEER), because TEER decrease is associated with BBB compromise. Tight junction (TJ) proteins (occludin, claudin-5, and zonula occludens-1) and endothelial protein C receptor (EPCR) were analyzed.

RESULTS

Thrombin decreased TEER and progesterone prevented that decrease. TJ proteins and EPCR were also decreased after thrombin treatment and progesterone treatment blocked that effect.

CONCLUSION

Progesterone can attenuate thrombin-induced BBB disruption by blocking the degradation of TJ proteins and EPCR in bEnd.3 cells.