Estrogen stimulates neuronal nitric oxide synthase protein expression in human neutrophils

Estrogen deficiency-mediated osteoimmunity in postmenopausal osteoporosis

Postmenopausal osteoporosis (PMO) is a common disease associated with aging, and estrogen deficiency is considered to be the main cause of PMO. Recently, however, osteoimmunology has been revealed to be closely related to PMO. On the one hand, estrogen deficiency directly affects the activity of bone cells (osteoblasts, osteoclasts, osteocytes). On the other hand, estrogen deficiency-mediated osteoimmunity also plays a crucial role in bone loss in PMO. In this review, we systematically describe the progress of the mechanisms of bone loss in PMO, estrogen deficiency-mediated osteoimmunity, the differences between PMO patients and postmenopausal populations without osteoporosis, and estrogen deficiency-mediated immune cells (T cells, B cells, macrophages, neutrophils, dendritic cells, and mast cells) activity. The comprehensive summary of this paper provides a clear knowledge context for future research on the mechanism of PMO bone loss.

Sports and Immunity, from the recreational to the elite athlete

The pivotal role of the immune system in physical activity is well-established. While interactions are complex, they tend to constitute discrete immune responses. Moderate intensity exercise causes leukocytosis with a mild anti-inflammatory cytokine profile and immunoenhancement. Above a threshold of intensity, lactate-mediated IL-6 release causes a proinflammatory state followed by a depressed inflammatory state, which stimulates immune adaptation and longer term cardiometabolic enhancement. Exercise-related immune responses are modulated by sex, age and immunonutrition. At all ability levels, these factors collectively affect the immune balance between enhancement or overload and dysfunction. Excessive training, mental stress or insufficient recovery risks immune cell exhaustion and hypothalamic pituitary axis (HPA) stress responses causing immunodepression with negative impacts on performance or general health. Participation in sport provides additional immune benefits in terms of ensuring regularity, social inclusion, mental well-being and healthier life choices in terms of diet and reduced smoking and alcohol, thereby consolidating healthy lifestyles and longer term health. Significant differences exist between recreational and professional athletes in terms of inherent characteristics, training resilience and additional stresses arising from competition schedules, travel-related infections and stress. Exercise immunology examines the central role of immunity in exercise physiology and straddles multiple disciplines ranging from neuroendocrinology to nutrition and genetics, with the aim of guiding athletes to train optimally and safely. This review provides a brief outline of the main interactions of immunity and exercise, some influencing factors, and current guidance on maintaining immune health.

Association of neutrophil to lymphocyte ratio with bone mineral density in post-menopausal women: a systematic review and meta-analysis

BACKGROUND

We conducted a systematic review and meta-analysis to compare the neutrophil lymphocyte ratio (NLR) levels between women with post-menopausal osteopenia or osteoporosis to those with normal bone mineral density (BMD).

METHODS

We used Web of Science, PubMed, and Scopus to conduct a systematic search for relevant publications published before June 19, 2022, only in English language. We reported standardized mean difference (SMD) with a 95% confidence interval (CI). Because a significant level of heterogeneity was found, we used the random-effects model to calculate pooled effects. We used the Newcastle-Ottawa scale for quality assessment.

RESULTS

Overall, eight articles were included in the analysis. Post-menopausal women with osteoporosis had elevated levels of NLR compared to those without osteoporosis (SMD = 1.03, 95% CI = 0.18 to 1.88, p = 0.017, I2 = 98%). In addition, there was no difference between post-menopausal women with osteopenia and those without osteopenia in neutrophil lymphocyte ratio (NLR) levels (SMD = 0.58, 95% CI=-0.08 to 1.25, p = 0.085, I2 = 96.8%). However, there was no difference between post-menopausal women with osteoporosis and those with osteopenia in NLR levels (SMD = 0.75, 95% CI=-0.01 to 1.51, p = 0.05, I2 = 97.5%, random-effect model).

CONCLUSION

The results of this study point to NLR as a potential biomarker that may be easily introduced into clinical settings to help predict and prevent post-menopausal osteoporosis.

Estradiol Treatment Enhances Behavioral and Molecular Changes Induced by Repetitive Trigeminal Activation in a Rat Model of Migraine

A migraine is a neurological condition that can cause multiple symptoms. It is up to three times more common in women than men, thus, estrogen may play an important role in the appearance attacks. Its exact pathomechanism is still unknown; however, the activation and sensitization of the trigeminal system play an essential role. We aimed to use an animal model, which would better illustrate the process of repeated episodic migraine attacks to reveal possible new mechanisms of trigeminal pain chronification. Twenty male (M) and forty ovariectomized (OVX) female adult rats were used for our experiment. Male rats were divided into two groups (M + SIF, M + IS), while female rats were divided into four groups (OVX + SIF, OVX + IS, OVX + E2 + SIF, OVX + E2 + IS); half of the female rats received capsules filled with cholesterol (OVX + SIF, OVX + IS), while the other half received a 1:1 mixture of cholesterol and 17β-estradiol (OVX + E2 + SIF, OVX + E2 + IS). The animals received synthetic interstitial fluid (SIF) (M + SIF, OVX + SIF, OVX + E2 + SIF) or inflammatory soup (IS) (M + IS, OVX + IS, OVX + E2 + IS) treatment on the dural surface through a cannula for three consecutive days each week (12 times in total). Behavior tests and immunostainings were performed. After IS application, a significant decrease was observed in the pain threshold in the M + IS (0.001 < p < 0.5), OVX + IS (0.01 < p < 0.05), and OVX + E2 + IS (0.001 < p < 0.05) groups compared to the control groups (M + SIF; OVX + SIF, OVX + E2 + SIF). The locomotor activity of the rats was lower in the IS treated groups (M + IS, 0.01 < p < 0.05; OVX + IS, p < 0.05; OVX + E2 + IS, 0.001 < p < 0.05), and these animals spent more time in the dark room (M + IS, p < 0.05; OVX + IS, 0.01 < p < 0.05; OVX + E2 + IS, 0.001 < p < 0.01). We found a significant difference between M + IS and OVX + E2 + IS groups (p < 0.05) in the behavior tests. Furthermore, IS increased the area covered by calcitonin gene-related peptide (CGRP) immunoreactive (IR) fibers (M + IS, p < 0.01; OVX + IS, p < 0.01; OVX + E2 + IS, p < 0.001) and the number of neuronal nitric oxide synthase (nNOS) IR cells (M + IS, 0.001< p < 0.05; OVX + IS, 0.01 < p < 0.05; OVX + E2 + IS, 0.001 < p < 0.05) in the caudal trigeminal nucleus (TNC). There was no difference between M + IS and OVX + IS groups; however, the area was covered by CGRP IR fibers (0.01 < p < 0.05) and the number of nNOS IR cells was significantly higher in the OVX + E2 + IS (p < 0.05) group than the other two IS- (M + IS, OVX + IS) treated animals. Overall, repeated administration of IS triggers activation and sensitization processes and develops nociceptive behavior changes. CGRP and nNOS levels increased significantly in the TNC after IS treatments, and moreover, pain thresholds and locomotor activity decreased with the development of photophobia. In our model, stable high estradiol levels proved to be pronociceptive. Thus, repeated trigeminal activation causes marked behavioral changes, which is more prominent in rats treated with estradiol, also reflected by the expression of the sensitization markers of the trigeminal system.

Cerebral arteriolar and neurovascular dysfunction after chemically induced menopause in mice

Cognitive decline is linked to decreased cerebral blood flow, particularly in women after menopause. Impaired cerebrovascular function precedes the onset of dementia, possibly because of reduced functional dilation in parenchymal arterioles. These vessels are bottlenecks of the cerebral microcirculation, and dysfunction can limit functional hyperemia in the brain. Large-conductance Ca2+-activated K+ channels (BKCa) are the final effectors of several pathways responsible for functional hyperemia, and their expression is modulated by estrogen. However, it remains unknown whether BKCa function is altered in cerebral parenchymal arterioles after menopause. Using a chemically induced model of menopause, the 4-vinylcyclohexene diepoxide (VCD) model, which depletes follicles while maintaining intact ovaries, we hypothesized that menopause would be associated with reduced functional vasodilatory responses in cerebral parenchymal arterioles of wild-type mice via reduced BKCa function. Using pressure myography of isolated parenchymal arterioles, we observed that menopause (Meno) induced a significant increase in spontaneous myogenic tone. Endothelial function, assessed as nitric oxide production and dilation after cholinergic stimulation or endothelium-dependent hyperpolarization pathways, was unaffected by Meno. BKCa function was significantly impaired in Meno compared with control, without changes in voltage-gated K+ channel activity. Cerebral functional hyperemia, measured by laser-speckle contrast imaging during whisker stimulation, was significantly blunted in Meno mice, without detectable changes in basal perfusion. However, behavioral testing identified no change in cognition. These findings suggest that menopause induces cerebral microvascular and neurovascular deficits.NEW & NOTEWORTHY Cerebral parenchymal arterioles from menopause mice showed increased myogenic tone. We identified an impairment in smooth muscle cell BKCa channel activity, without a reduction in endothelium-dependent dilation or nitric oxide production. Microvascular dysfunction was associated with a reduction in neurovascular responses after somatosensory stimulation. Despite the neurovascular impairment, cognitive abilities were maintained in menopausal mice.

NOS1 mutations cause hypogonadotropic hypogonadism with sensory and cognitive deficits that can be reversed in infantile mice

The nitric oxide (NO) signaling pathway in hypothalamic neurons plays a key role in the regulation of the secretion of gonadotropin-releasing hormone (GnRH), which is crucial for reproduction. We hypothesized that a disruption of neuronal NO synthase (NOS1) activity underlies some forms of hypogonadotropic hypogonadism. Whole-exome sequencing was performed on a cohort of 341 probands with congenital hypogonadotropic hypogonadism to identify ultrarare variants in NOS1. The activity of the identified NOS1 mutant proteins was assessed by their ability to promote nitrite and cGMP production in vitro. In addition, physiological and pharmacological characterization was carried out in a Nos1-deficient mouse model. We identified five heterozygous NOS1 loss-of-function mutations in six probands with congenital hypogonadotropic hypogonadism (2%), who displayed additional phenotypes including anosmia, hearing loss, and intellectual disability. NOS1 was found to be transiently expressed by GnRH neurons in the nose of both humans and mice, and Nos1 deficiency in mice resulted in dose-dependent defects in sexual maturation as well as in olfaction, hearing, and cognition. The pharmacological inhibition of NO production in postnatal mice revealed a critical time window during which Nos1 activity shaped minipuberty and sexual maturation. Inhaled NO treatment at minipuberty rescued both reproductive and behavioral phenotypes in Nos1-deficient mice. In summary, lack of NOS1 activity led to GnRH deficiency associated with sensory and intellectual comorbidities in humans and mice. NO treatment during minipuberty reversed deficits in sexual maturation, olfaction, and cognition in Nos1 mutant mice, suggesting a potential therapy for humans with NO deficiency.

Gastrointestinal and hepatic diseases during the COVID-19 pandemic: Manifestations, mechanism and management

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is considered the causative pathogen of coronavirus disease 2019 (COVID-19) and has become an international danger to human health. Although respiratory transmission and symptoms are still the essential manifestations of COVID-19, the digestive system could be an unconventional or supplementary route for COVID-19 to be transmitted and manifested, most likely due to the presence of angiotensin-converting enzyme 2 (ACE2) in the gastrointestinal tract. In addition, SARS-CoV-2 can trigger hepatic injury via direct binding to the ACE2 receptor in cholangiocytes, antibody-dependent enhancement of infection, systemic inflammatory response syndrome, inflammatory cytokine storms, ischemia/reperfusion injury, and adverse events of treatment drugs. Gastrointestinal symptoms, including anorexia, nausea, vomiting, and diarrhea, which are unusual in patients with COVID-19, and some digestive signs may occur without other respiratory symptoms. Furthermore, SARS-CoV-2 can be found in infected patients' stool, demonstrating the likelihood of transmission through the fecal-oral route. In addition, liver function should be monitored during COVID-19, particularly in more severe cases. This review summarizes the evidence for extra-pulmonary manifestations, mechanisms, and management of COVID-19, particularly those related to the gastrointestinal tract and liver.

Interaction between bone and immune cells: Implications for postmenopausal osteoporosis

Postmenopausal osteoporosis is a systemic disease characterized by the loss of bone mass and increased bone fracture risk largely resulting from significantly reduced levels of the hormone estrogen after menopause. Besides the direct negative effects of estrogen-deficiency on bone, indirect effects of altered immune status in postmenopausal women might contribute to ongoing bone destruction, as postmenopausal women often display a chronic low-grade inflammatory phenotype with altered cytokine expression and immune cell profile. In this context, it was previously shown that various immune cells interact with osteoblasts and osteoclasts either via direct cell-cell contact, or more likely via paracrine mechanisms. For example, specific subtypes of T lymphocytes express TNFα, which was shown to increase osteoblast apoptosis and to indirectly stimulate osteoclastogenesis via B cell-produced receptor-activator of NF-κB ligand (RANKL), thereby triggering bone loss during postmenopausal osteoporosis. T_h17 cells release interleukin-17 (IL-17), which directs mesenchymal stem cell differentiation towards the osteogenic lineage, but also indirectly increases osteoclast differentiation. B lymphocytes are a major regulator of osteoclast formation via granulocyte colony-stimulating factor secretion and the RANKL/osteoprotegerin system under estrogen-deficient conditions. Macrophages might act differently on bone cells dependent on their polarization profile and their secreted paracrine factors, which might have implications for the development of postmenopausal osteoporosis, because macrophage polarization is altered during disease progression. Likewise, neutrophils play an important role during bone homeostasis, but their over-activation under estrogen-deficient conditions contributes to osteoblast apoptosis via the release of reactive oxygen species and increased osteoclastogenesis via RANKL signaling. Furthermore, mast cells might be involved in the development of postmenopausal osteoporosis, because they store high levels of osteoclastic mediators, including IL-6 and RANKL, in their granules and their numbers are greatly increased in osteoporotic bone. Additionally, bone fracture healing is altered under estrogen-deficient conditions with the increased presence of pro-inflammatory cytokines, including IL-6 and Midkine, which might contribute to healing disturbances. Consequently, in addition to the direct negative influence of estrogen-deficiency on bone, immune cell alterations contribute to the pathogenesis of postmenopausal osteoporosis.

Gender Differences in Low-Molecular-Mass-Induced Acute Lung Inflammation in Mice

Gender differences in pulmonary inflammation have been well documented. Although low molecular mass hyaluronan (LMMHA) is known to trigger pulmonary lung inflammation, sex differences in susceptibility to LMMHA are still unknown. In this study, we test the hypothesis that mice may display sex-specific differences after LMMHA administration. After LMMHA administration, male mice have higher neutrophil, cytokine, and chemokine counts compared to that of their female counterparts. Additionally, Ovariectomized (OVX) mice show greater LMMHA-induced inflammation compared to that of mice with intact ovaries. Injections of OVX mice with 17β-estradiol can decrease inflammatory responses in the OVX mice. These results show that ovarian hormones regulate LMMHA induced lung inflammation.

Nitrergic perivascular innervation in health and diseases: Focus on vascular tone regulation

For a long time, the vascular tone was considered to be regulated exclusively by tonic innervation of vasoconstrictor adrenergic nerves. However, accumulating experimental evidence has revealed the existence of nerves mediating vasodilatation, including perivascular nitrergic nerves (PNN), in a wide variety of mammalian species. Functioning of nitrergic vasodilator nerves is evidenced in several territories, including cerebral, mesenteric, pulmonary, renal, penile, uterine and cutaneous arteries. Nitric oxide (NO) is the main neurogenic vasodilator in cerebral arteries and acts as a counter-regulatory mechanism for adrenergic vasoconstriction in other vascular territories. In the penis, NO relaxes the vascular and cavernous smooth muscles leading to penile erection. Furthermore, when interacting with other perivascular nerves, NO can act as a neuromodulator. PNN dysfunction is involved in the genesis and maintenance of vascular disorders associated with arterial and portal hypertension, diabetes, ageing, obesity, cirrhosis and hormonal changes. For example defective nitrergic function contributes to enhanced sympathetic neurotransmission, vasoconstriction and blood pressure in some animal models of hypertension. In diabetic animals and humans, dysfunctional nitrergic neurotransmission in the corpus cavernosum is associated with erectile dysfunction. However, in some vascular beds of hypertensive and diabetic animals, an increased PNN function has been described as a compensatory mechanism to the increased vascular resistance. The present review summarizes current understanding on the role of PNN in control of vascular tone, its alterations under different conditions and the associated mechanisms. The knowledge of these changes can serve to better understand the mechanisms involved in these disorders and help in planning new treatments.

Racial and Gender-Based Differences in COVID-19

The novel coronavirus disease (COVID-19) has become a global health crisis since its first appearance in Wuhan, China. Current epidemiological studies suggest that COVID-19 affects older patients with multiple comorbidities, such as hypertension, obesity, and chronic lung diseases. The differences in the incidence and severity of COVID-19 are likely to be multifaceted, depending on various biological, social, and economical factors. Specifically, the socioeconomic differences and psychological impact of COVID-19 affecting males and females are essential in pandemic mitigation and preparedness. Previous clinical studies have shown that females are less susceptible to acquire viral infections and reduced cytokine production. Female patients have a higher macrophage and neutrophil activity as well as antibody production and response. Furthermore, in-vivo studies of the angiotensin-converting enzyme 2 (ACE2) showed higher expression in the kidneys of male than female patients, which may explain the differences in susceptibility and progression of COVID-19 between male and female patients. However, it remains unknown whether the expression of ACE2 differs in the lungs of male or female patients. Disparities in healthcare access and socioeconomic status between ethnic groups may influence COVID-19 rates. Ethnic groups often have higher levels of medical comorbidities and lower socioeconomic status, which may increase their risk of contracting COVID-19 through weak cell-mediated immunity. In this article, we examine the current literature on the gender and racial differences among COVID-19 patients and further examine the possible biological mechanisms underlying these differences.

Estrogen signaling effects on muscle-specific immune responses through controlling the recruitment and function of macrophages and T cells

Background

Estrogen signaling is indispensable for muscle regeneration, yet the role of estrogen in the development of muscle inflammation, especially in the intramuscular T cell response, and the influence on the intrinsic immuno-behaviors of myofibers remain largely unknown. We investigated this issue using the mice model of cardiotoxin (CTX)-induced myoinjury, with or without estrogen level adjustment.

Methods

CTX injection i.m. (tibialis anterior, TA) was performed for preparing mice myoinjury model. Injection s.c. of 17β-estradiol (E₂) or estrogen receptor antagonist 4-OHT, or ovariectomy (OVX), was used to change estrogen level of animal models in vivo. Serum E₂ level was evaluated by ELISA. Gene levels of estrogen receptor (ERs) and cytokines/chemokines in inflamed muscle were monitored by qPCR. Inflammatory infiltration was observed by immunofluorescence. Macrophage and T cell phenotypes were analyzed by FACS. Immunoblotting was used to assess protein levels of ERs and immunomolecules in C₂C₁₂ myotubes treated with E₂ or 4-OHT, in the presence of IFN-γ.

Results

We monitored the increased serum E₂ level and the upregulated ERβ in regenerated myofibres after myotrauma. The absence of estrogen in vivo resulted in the more severe muscle inflammatory infiltration, involving the recruitment of monocyte/macrophage and CD4⁺ T cells, and the heightened proinflammatory (M1) macrophage. Moreover, estrogen signaling loss led to Treg cells infiltration decrease, Th1 response elevation in inflamed muscle, and the markedly expression upregulation of immunomolecules in IFN-γ-stimulated C₂C₁₂ myotubes in vitro.

Conclusion

Our data suggest that estrogen is a positive intervention factor for muscle inflammatory response, through its effects on controlling intramuscular infiltration and phenotypes of monocytes/macrophages, on affecting accumulation and function of Treg cells, and on suppressing Th1 response in inflamed muscle. Our findings also imply an inhibition effect of estrogen on the intrinsic immune behaviors of muscle cells.

Soluble guanylate cyclase isoenzymes: The expression of α1, α2, β1, and β2 subunits in the benign and malignant breast tumors

Soluble guanylate cyclase (sGC) encompasses α and β subunits. This study examined the expression of α1, α2, β1, and β2 subunits in the malignant and benign breast tumors using the Western blot  analysis. Both benign and malignant tumors showed a significantly higher expression of the α1 subunit in comparison with normal tissues (p < 0.0001). In contrast, the expression of α2 and β2 sGC were significantly lower in these tumors than normal tissues (p < .0015 and p < .001, p < .007 and p < .0001, respectively). The expression level of α1 sGC was significantly correlated with ER + PR+ (p < .0001). A significant correlation was also detected for sGC-α1 and -α2 expression with c-erbB2-negative status (p < .01). However, the expression level of sGC was not associated with tumor stage, tumor grade, or other clinicopathological features. In conclusion, as the expression of α1 sGC is upregulated and α2 and β2 sGC are downregulated in malignant breast tumors. Variations in the expression of sGC isoenzymes may be suggested as an indicator to confirm the enzyme antitumor activity.

Metabolic control and sex: A focus on inflammatory-linked mediators

Men and women have many differing biological and physiological characteristics. Thus, it is no surprise that the control of metabolic processes and the mechanisms underlying metabolic-related diseases have sex-specific components. There is a clear metabolic sexual dimorphism in that up until midlife, men have a far greater likelihood of acquiring cardio-metabolic disease than women. Following menopause, however, this difference is reduced, suggestive of a protective role of the female sex hormones. Inflammatory processes have been implicated in the pathogenesis of cardio-metabolic disease with human studies correlating metabolic disease acquisition or risk with levels of various inflammatory markers. Rodent studies employing genetic modifications or novel pharmacological approaches have provided mechanistic insight into the role of these inflammatory mediators. Sex differences impact inflammatory processes and the subsequent biological response. As a consequence, this may affect how inflammation alters metabolic processes between the sexes. Recently, some of our work in the field of inflammatory genes and metabolic control identified a sexual dimorphism in a preclinical model and caused us to question the frequency and scale of such findings in the literature. This review concentrates on inflammatory-related signalling in relation to obesity, insulin resistance, and type 2 diabetes and highlights the differences observed between males and females. Differences in the activation and signalling of various inflammatory genes and proteins present another reason why studying both male and female patients or animals is important in the context of understanding and finding therapeutics for metabolic-related disease. LINKED ARTICLES: This article is part of a themed section on The Importance of Sex Differences in Pharmacology Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.21/issuetoc.

Equilin displays similar endothelium-independent vasodilator potential to 17β-estradiol regardless of lower potential to inhibit calcium entry

Conjugated equine estrogens (CEE) have been widely used by women who seek to relieve symptoms of menopause. Despite evidence describing protective effects against risk factors for cardiovascular diseases by naturally occurring estrogens, little is known about the vascular effects of equilin, one of the main components of CEE and not physiologically present in women. In this regard, the present study aims to compare the vascular effects of equilin in an experimental model of hypertension with those induced by 17β-estradiol. Resistance mesenteric arteries from female spontaneously hypertensive rats (SHR) were used for recording isometric tension in a small vessel myograph. As effectively as 17β-estradiol, equilin evoked a concentration-dependent relaxation in mesenteric arteries from female SHRs contracted with KCl, U46619, PDBu or ET-1. Equilin-induced vasodilation does not involve classical estrogen receptor activation, since the estrogen receptor antagonist (ICI 182,780) failed to inhibit relaxation in U46619-precontracted mesenteric arteries. Vasorelaxation was not affected by either endothelium removal or by inhibiting the release or action of endothelium-derived factors. Incubation with L-NAME (NOS inhibitor), ODQ (guanylyl cyclase inhibitor) or KT5823 (inhibitor of protein kinase G) did not affect equilin-induced relaxation. Similarly, indomethacin (COX inhibitor) or blockage of potassium channels with tetraethylammonium, glibenclamide, 4-aminopyridine, or ouabain did not affect equilin-induced relaxation. Inhibitors of adenylyl cyclase SQ22536 or protein kinase A (KT5720) also had no effects on equilin-induced relaxation. While 17β-estradiol inhibited calcium (Ca²⁺) -induced contractions in high-K⁺ depolarization medium in a concentration-dependent manner, equilin induced a slight rightward-shift in the contractile responses to Ca²⁺. Comparable pattern of responses were observed in the concentration-response curves to (S)-(-)-Bay K 8644, a L-type Ca²⁺ channel activator. Equilin was unable to block the transitory contraction produced by caffeine-induced Ca²⁺ release from intracellular stores. In conclusion, equilin blocks L-type Ca²⁺ channels less effectively than 17β-estradiol. Despite its lower effectiveness, equilin equally relaxes resistance mesenteric arteries by blocking Ca²⁺ entry on smooth muscle.

Neuronal nitric oxide synthase and affective disorders

Affective disorders including major depressive disorder (MDD), bipolar disorder (BPD), and general anxiety affect more than 10% of population in the world. Notably, neuronal nitric oxide synthase (nNOS), a downstream signal molecule of N-methyl-D-aspartate receptors (NMDARs) activation, is abundant in many regions of the brain such as the prefrontal cortex (PFC), hippocampus, amygdala, dorsal raphe nucleus (DRN), locus coeruleus (LC), and hypothalamus, which are closely associated with the pathophysiology of affective disorders. Decreased levels of the neurotransmitters including 5-hydroxytryptamine or serotonin (5-HT), noradrenalin (NA), and dopamine (DA) as well as hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis are common pathological changes of MDD, BPD, and anxiety. Increasing data suggests that nNOS in the hippocampus play a crucial role in the etiology of MDD whereas nNOS-related dysregulation of the nitrergic system in the LC is closely associated with the pathogenesis of BPD. Moreover, hippocampal nNOS is implicated in the role of serotonin receptor 1 A (5-HTR1 A) in modulating anxiety behaviors. Augment of nNOS and its carboxy-terminal PDZ ligand (CAPON) complex mediate stress-induced anxiety and disrupting the nNOS-CAPON interaction by small molecular drug generates anxiolytic effect. To date, however, the function of nNOS in affective disorders is not well reviewed. Here, we summarize works about nNOS and its signal mechanisms implicated in the pathophysiology of affective disorders. On the basis of this review, it is suggested that future research should more fully focus on the role of nNOS in the pathomechanism and treatment of affective disorders.

Sex Hormones Regulate Innate Immune Cells and Promote Sex Differences in Respiratory Virus Infection

Sex differences in the incidence and severity of respiratory virus infection are widely documented in humans and murine models and correlate with sex biases in numbers and/or functional responses of innate immune cells in homeostasis and lung infection. Similarly, changes in sex hormone levels upon puberty, pregnancy, and menopause/aging are associated with qualitative and quantitative differences in innate immunity. Immune cells express receptors for estrogens (ERα and ERβ), androgens (AR), and progesterone (PR), and experimental manipulation of sex hormone levels or receptors has revealed that sex hormone receptor activity often underlies sex differences in immune cell numbers and/or functional responses in the respiratory tract. While elegant studies have defined mechanistic roles for sex hormones and receptors in innate immune cells, much remains to be learned about the cellular and molecular mechanisms of action of ER, PR, and AR in myeloid cells and innate lymphocytes to promote the initiation and resolution of antiviral immunity in the lung. Here, we review the literature on sex differences and sex hormone regulation in innate immune cells in the lung in homeostasis and upon respiratory virus infection.

Associations Between Heart Rate Recovery Dynamics With Estradiol Levels in 20 to 60 Year-Old Sedentary Women

It is hypothesized that estradiol levels, as well as aging, influence cardiac autonomic function in women. The main aim of this study was to test the correlations between heart rate recovery (HRR) dynamics, as a proxy of cardiac autonomic function, with estradiol levels and age in women. This cross-sectional study involved 44 healthy women. Heart rate (HR) data were obtained beat-by-beat during the entire experiment. Maximal incremental exercise testing (IET) on a cycle ergometer was performed followed by 6 min of recovery. During the IET recovery period, the overall HRR dynamics were evaluated by exponential data modeling (time constant "τ") where shorter τ indicates faster HRR adjustment. Considering the cardiac autonomic complexity, HRR dynamics were also evaluated by delta (Δ) analysis considering different HR data intervals. The relationship between HRR dynamics, estradiol levels and age was tested by Pearson product-moment correlation. The overall HRR dynamics (i.e., τ) were statistically correlated with age (r = 0.58, p < 0.001) and estradiol levels (r = -0.37, p = 0.01). The Δ analysis showed that the slower overall HRR associated with aging was a consequence of slower dynamics occurring within the 45-210 s interval, indicating slower sympathetic withdrawal. In conclusion, aging effects on HRR in women seems to be correlated with a slower sympathetic withdrawal. In addition, the cardioprotective effect previously associated with estradiol seems not to influence the autonomic modulation during exercise recovery periods in women.

Engineering in-vitro stem cell-based vascularized bone models for drug screening and predictive toxicology

The production of veritable in-vitro models of bone tissue is essential to understand the biology of bone and its surrounding environment, to analyze the pathogenesis of bone diseases (e.g., osteoporosis, osteoarthritis, osteomyelitis, etc.), to develop effective therapeutic drug screening, and to test potential therapeutic strategies. Dysregulated interactions between vasculature and bone cells are often related to the aforementioned pathologies, underscoring the need for a bone model that contains engineered vasculature. Due to ethical restraints and limited prediction power of animal models, human stem cell-based tissue engineering has gained increasing relevance as a candidate approach to overcome the limitations of animals and to serve as preclinical models for drug testing. Since bone is a highly vascularized tissue, the concomitant development of vasculature and mineralized matrix requires a synergistic interaction between osteogenic and endothelial precursors. A number of experimental approaches have been used to achieve this goal, such as the combination of angiogenic factors and three-dimensional scaffolds, prevascularization strategies, and coculture systems. In this review, we present an overview of the current models and approaches to generate in-vitro stem cell-based vascularized bone, with emphasis on the main challenges of vasculature engineering. These challenges are related to the choice of biomaterials, scaffold fabrication techniques, and cells, as well as the type of culturing conditions required, and specifically the application of dynamic culture systems using bioreactors.

Sex differences in sympathetic vasoconstrictor responsiveness and sympatholysis

Sex differences in the neurovascular control of blood pressure and vascular resistance have been reported. However, the mechanisms underlying the modulatory influence of sex have not been fully elucidated. Nitric oxide (NO) has been shown to inhibit sympathetic vasoconstriction in resting and contracting skeletal muscle, and estrogen modulates NO synthase (NOS) expression and NO bioavailability. Therefore NO-mediated inhibition of sympathetic vasoconstriction may be enhanced in females. Thus the purpose of the present study was to investigate the hypothesis that sympathetic vasoconstrictor responsiveness would be blunted and NO-mediated inhibition of sympathetic vasoconstriction would be enhanced in females compared with males. Male (M; n = 8) and female (F; n = 10) Sprague-Dawley rats were anesthetized and surgically instrumented for measurement of arterial blood pressure and femoral artery blood flow and stimulation of the lumbar sympathetic chain. The percentage change of femoral vascular conductance in response to sympathetic chain stimulation delivered at 2 and 5 Hz was determined at rest and during triceps surae muscle contraction before (control) and after NOS blockade [N^ω-nitro-l-arginine methyl ester (l-NAME), 10 mg/kg iv]. At rest, sympathetic vasoconstrictor responsiveness was augmented (P < 0.05) in female compared with male rats at 2 Hz [F: -33 ± 8% (SD); M: -26 ± 6%] but was not different at 5 Hz (F: -55 ± 7%; M: -47 ± 7%). During muscle contraction, evoked vasoconstriction was similar (P > 0.05) in females and males at 2 Hz (F: -12 ± 5%; M: -13 ± 5%) but was blunted (P < 0.05) in females compared with males at 5 Hz (F: -24 ± 5%; M: -34 ± 8%). l-NAME increased (P < 0.05) sympathetic vasoconstrictor responsiveness in both groups at rest and during contraction. Contraction-mediated inhibition of vasoconstriction (sympatholysis) was enhanced (P < 0.05) in females compared with males; however, sympatholysis was not different (P > 0.05) between males and females in the presence of NOS blockade, indicating that NO-mediated sympatholysis was augmented in female rats. These data suggest that sex modulates sympathetic vascular control in resting and contracting skeletal muscle and that a portion of the enhanced sympatholysis in female rats was NO dependent.NEW & NOTEWORTHY Sex differences in the neurovascular regulation of blood pressure and vascular resistance have been documented. However, our understanding of the underlying mechanisms that mediate these differences is incomplete. The present study demonstrates that female rats have an enhanced capacity to inhibit sympathetic vasoconstriction during exercise (sympatholysis) and that NO mediates a portion of the enhanced sympatholysis.

Human cells involved in atherosclerosis have a sex

The influence of sex has been largely described in cardiovascular diseases. Atherosclerosis is a complex process that involves many cell types such as vessel cells, immune cells and endothelial progenitor cells; however, many, if not all, studies do not report the sex of the cells. This review focuses on sex differences in human cells involved in the atherosclerotic process, emphasizing the role of sex hormones. Furthermore, we report sex differences and issues related to the processes that determine the fate of the cells such as apoptotic and autophagic mechanisms. The analysis of the data reveals that there are still many gaps in our knowledge regarding sex influences in atherosclerosis, largely for the cell types that have not been well studied, stressing the urgent need for a clear definition of experimental conditions and the inclusion of both sexes in preclinical studies.

Sex-driven differences in immunological responses: challenges and opportunities for the immunotherapies of the third millennium

PURPOSE OF THE STUDY

Male-based studies, both at the biochemical and at the pre-clinical/clinical trial levels, still predominate in the scientific community. Many studies are based on the wrong assumption that both sexes are fundamentally identical in their response to treatments. As a result, findings obtained mainly in males are applied to females, resulting in negative consequences female patients. In cancer immunotherapy, there is still a scarce focus on this topic. Here we review the main differences in immune modulation and immune system biology between males and females with a particular focus on how these differences affect cancer immunotherapy and cancer vaccines.

METHODS

We reviewed articles published on PubMed from 1999 to 2014, using the keywords: sex hormones, immune response, estrogen, immunotherapy, testosterone, cancer vaccines, sex-based medicine. We also present new data wherein the expression of the cancer testis antigen, Ropporin-1, was determined in patients with multiple myeloma, showing that the expression of Ropporin-1 was influenced by sex.

RESULTS

Male and female immune systems display radical differences mainly due to the immune regulatory effects of sex hormones. These differences might have a dramatic impact on the immunological treatment of cancer. Moreover, the expression of tumor antigens that can be targeted by anti-cancer vaccines is associated with sex.

CONCLUSION

Future clinical trials focusing on cancer immunotherapy will need to take into account the differences in the immune response and in the frequency of target antigen expression between male and females, in order to optimize these anti-cancer immunotherapies of the third millennium.

Influence of sex steroids on inflammation and bone metabolism

Sex steroids are central to sexual development and reproduction, exerting pleiotropic effects on multiple tissues and organs throughout the lifespan of humans. Sex steroids are fundamental to skeletal development, bone homeostasis and immune function. The composite effect of sex-specific genetic architecture and circulating levels of sex-steroid hormones closely parallels differences in the immune response and may account for corresponding sex-related differences in risk for chronic periodontitis, with men exhibiting greater susceptibility than women. Age-associated reductions in sex steroids also provide insight into apparent temporal increases in susceptibility to periodontitis and alveolar bone loss, particularly among women. Chronic infection and inflammatory conditions, such as periodontal disease, provide a unique platform for exploring the interface of sex steroids, immunity and bone metabolism.

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

Stroke is the third leading cause of death and the primary cause of disability in the developed world. Experimental and clinical data indicate that stroke is a sexually dimorphic disease, with males demonstrating an enhanced intrinsic sensitivity to ischemic damage throughout most of their lifespan. The neuroprotective role of estrogen in the female brain is well established, however, estrogen exposure can also be deleterious, especially in older women. The mechanisms for this remain unclear. Our current understanding is based on studies examining estrogen as it relates to neuronal injury, yet cerebral ischemia also induces a robust sterile inflammatory response involving local and systemic immune cells. Despite the potent anti-inflammatory effects of estrogen, few studies have investigated the contribution of estrogen to sex differences in the inflammatory response to stroke. This review examines the potential role for estrogen-mediated immunoprotection in ischemic injury.

Expression pattern and signalling pathways in neutrophil like HL-60 cells after treatment with estrogen receptor selective ligands

Estrogens play a role in the regulation of genes associated with inflammation and immunity in neutrophils. Estrogen signalling is mediated by estrogen receptor (ER)α, ERβ, and G-protein-coupled estrogen receptor-1 (GPER). The mechanisms by which estrogen regulate genes in neutrophils are poorly understood. Our aim was to identify the presence of ERs and to characterize estrogen responsive genes in terminally differentiated neutrophil like HL-60 (nHL-60) cells using estradiol and selective ER agonists. ERs were identified by Western blotting and immunocytochemistry. Microarray technique was used to screen for differentially expressed genes and the selected genes were verified by quantitative PCR. We show the presence of functional ERα, ERβ and GPER. Microarray analysis showed the presence of genes that are uniquely regulated by a single ligand and also genes that are regulated by multiple ligands. We conclude that ERs are functionally active in nHL-60 cells regulating genes involved in key physiological functions.

The influence of sex and gender on the immune response

The immune system and its orchestrated response are affected by a multitude of endogenous and exogenous factors, modulators and challenges. One of the most frequent differences described in the immune response is its vigor and activity in females compared to males, leading to the consequent increase in autoimmune conditions seen in the female population as well as differences in the immune response to pathogens and viruses. The following review summarizes our present knowledge on sex differences in the immune response, detailing the hormonal and genetic effects that have been proposed as explanatory mechanisms. Sexual hormones, mostly estrogen but also progesterone and testosterone, affect immune cells quantitatively and qualitatively. Relevant research has focused on the impact of hormones on cytokine production by the different effector cells, as well as impact on immunoglobulin production by B lymphocytes and activity of granulocytes and NK cells. The biological aspects are complemented by research data on the possible modulatory role of the X chromosome. In addition to biological differences, the frequently neglected role of gender as an immunomodulator is introduced and explored. Gender affects all areas of human life and consequently affects the different steps of an immune response. Exposure to various types of antigens, access to health promotion programs and health care, as well as prioritization of health needs and household resource allocation all affect the different response of females and males to immunologic challenges.

Acute sex hormone suppression reduces skeletal muscle sympathetic nerve activity

OBJECTIVES

Comparisons of sympathetic nervous system activity (SNA) between young and older women have produced equivocal results, in part due to inadequate control for potential differences in sex hormone concentrations, age, and body composition. The aim of the present study was to determine the effect of a short-term reduction in sex hormones on tonic skeletal muscle sympathetic nerve activity (MSNA), an indirect measure of whole body SNA, using an experimental model of sex hormone deficiency in young women. We also assessed the independent effects of estradiol and progesterone add-back therapy on MSNA.

METHODS

MSNA was measured in 9 women (30±2 years; mean±SE) on three separate occasions: during the mid-luteal menstrual cycle phase, on the fifth day of gonadotropin-releasing hormone antagonist (GnRHant) administration, and after 5 days add-back of either estradiol (n=4) or progesterone (n=3) during continued GnRHant administration.

RESULTS

In response to GnRHant, there were significant reductions in serum estradiol and progesterone (both p<0.01) and MSNA (25.0±1.9 vs. 19.2±2.4 bursts/min, p=0.04). Continued GnRHant plus add-back estradiol or progesterone resulted in a nonsignificant decrease (19.2±1.7 vs. 12.1±1.9 bursts/min, p=0.07) or increase (16.2±1.7 vs. 21.0±6.0 bursts/min, p=0.39), respectively, in MSNA when compared with GnRHant alone.

INTERPRETATION

The findings of this preliminary study suggest that short-term ovarian hormone suppression attenuates MSNA and that this may be related to the suppression of progesterone rather than estradiol.

Tetrahydrobiopterin restores diastolic function and attenuates superoxide production in ovariectomized mRen2.Lewis rats

After oophorectomy, mRen2.Lewis rats exhibit diastolic dysfunction associated with elevated superoxide, increased cardiac neuronal nitric oxide synthase (nNOS) expression, and diminished myocardial tetrahydrobiopterin (BH₄) content, effects that are attenuated with selective nNOS inhibition. BH₄ is an essential cofactor of nNOS catalytic activity leading to nitric oxide production. Therefore, we assessed the effect of 4 wk BH₄ supplementation on diastolic function and left ventricular (LV) remodeling in oophorectomized mRen2.Lewis rats compared with sham-operated controls. Female mRen2.Lewis rats underwent either bilateral ovariectomy (OVX) (n = 19) or sham operation (n = 13) at 4 wk of age. Beginning at 11 wk of age, OVX rats were randomized to receive either BH₄ (10 mg/kg · d) or saline, whereas the sham rats received saline via sc mini-pumps. Loss of ovarian hormones reduced cardiac BH₄ when compared with control hearts; this was associated with impaired myocardial relaxation, augmented filling pressures, increased collagen deposition, and thickened LV walls. Additionally, superoxide production increased and nitric oxide decreased in hearts from OVX compared with sham rats. Chronic BH₄ supplementation after OVX improved diastolic function and attenuated LV remodeling while restoring myocardial nitric oxide release and preventing reactive oxygen species generation. These data indicate that BH₄ supplementation protects against the adverse effects of ovarian hormonal loss on diastolic function and cardiac structure in mRen2.Lewis rats by restoring myocardial NO release and mitigating myocardial O₂⁻ generation. Whether BH₄ supplementation is a therapeutic option for the management of diastolic dysfunction in postmenopausal women will require direct testing in humans.

Neuronal nitric oxide synthase inhibition improves diastolic function and reduces oxidative stress in ovariectomized mRen2.Lewis rats

OBJECTIVE

The loss of estrogen in mRen2.Lewis rats leads to an exacerbation of diastolic dysfunction. Because specific neuronal nitric oxide synthase (nNOS) inhibition reverses renal damage in the same model, we assessed the effects of inhibiting neuronal nitric oxide on diastolic function, left ventricular remodeling, and the components of the cardiac nitric oxide system in ovariectomized (OVX) and sham-operated mRen2.Lewis rats treated with N5-(1-imino-3-butenyl)-L-ornithine (L-VNIO; 0.5 mg/kg per day for 28 d) or vehicle (saline).

METHODS

Female mRen2.Lewis rats underwent either bilateral oophorectomy (OVX; n = 15) or sham operation (or surgical procedure) (sham; n = 19) at 4 weeks of age. Beginning at 11 weeks of age, the rats were randomized to receive either L-VNIO or vehicle.

RESULTS

The surgical loss of ovarian hormones, particularly estrogen, led to exacerbated hypertension, impaired myocardial relaxation, diminished diastolic compliance, increased perivascular fibrosis, and increased relative wall thickness. The cardiac tetrahydrobiopterin-to-dihydrobiopterin levels were lower among OVX rats compared with sham-operated rats, and this altered cardiac biopterin profile was associated with enhanced myocardial superoxide production and decreased nitric oxide release. L-VNIO decreased myocardial reactive oxygen species production, increased nitrite concentrations, attenuated cardiac remodeling, and improved diastolic function.

CONCLUSIONS

Impaired relaxation, diastolic stiffness, and cardiac remodeling were found among OVX mRen2.Lewis rats. A possible mechanism for this unfavorable cardiac phenotype may have resulted from a deficiency in available tetrahydrobiopterin and subsequent increase in nNOS-derived superoxide and reduction in nitric oxide synthase metabolites within the heart. Selective nNOS inhibition with L-VNIO attenuated cardiac superoxide production and limited remodeling, leading to improved diastolic function in OVX mRen2.Lewis rats.

Nitric oxide production and blood corpuscle dynamics in response to the endocrine status of female rats

INTRODUCTION

Menopause is associated with marked changes in the endocrine profile, and increases the risk of vascular disease. However, the effect of hormones on the vascular system is still unclear. Therefore, the aim of this study was to examine the effects of endocrine status in female rats on nitric oxide (NO) production, inflammatory reactions and thrombus organization potency in the mesenteric microcirculation.

MATERIALS AND METHODS

Female Wistar rats were divided into four groups: proestrus, metestrus, ovariectomized (OVX) and OVX plus estradiol treatment (OVX+E2). NO was imaged using an NO-sensitive dye. The leukocyte and platelet velocities relative to the erythrocyte velocity (VW/VRC and VP/VRE, respectively) and thrombi sizes created by laser radiation were measured as thrombogenesis indices.

RESULTS

Changes in endocrine status did not affect vascular function in the arterioles. However, in venules, NO production, VW/VRC and VP/VRE were decreased in the OVX group compared with the proestrus and metestrus states. Thrombus size was significantly greater in the OVX group than in the proestrus and metestrus states. Administration of E2 for 2 weeks restored NO production, VW/VRC and VP/VRE to control levels.

CONCLUSIONS

Changes in endocrine status did not affect arterioles. In contrast, in venules, reduced estrogen levels led to a decrease in NO production, thereby increasing thrombogenesis. Estrogen replacement restored NO production and leukocyte and platelet velocities, reducing thrombus formation relative to OVX. Although it is unclear how E2 reduces thrombus formation, our results indicate that leukocyte and platelet adhesion to the endothelium is a target for E2 via NO.

Complementary inhibition of cerebral aneurysm formation by eNOS and nNOS

The rupture of cerebral aneurysm (CA) and subsequent subarachnoid hemorrhage can cause fatal results. Recent experimental findings have suggested that the mechanism of CA formation is based on chronic inflammation in arterial walls by hemodynamic force. Endothelial nitric oxide synthase (eNOS) protects arterial walls from vascular inflammation by relieving hemodynamic force through nitric oxide (NO) production. Thus, the expression and protective role of eNOS in CA formation have been investigated in this study. In this study, experimental induced rodent CA models by carotid ligation and systemic hypertension were used. The expression of eNOS was examined in rat CA models and revealed that it was decreased at the site of CA formation. Next, CA was induced in eNOS(-/-) mice to clarify the role of eNOS in CA formation. In eNOS(-/-) mice, the incidence of CA formation was similar to that found in wild-type mice. In CA walls of eNOS(-/-) mice, the expression of neuronal nitric oxide synthase (nNOS) was upregulated compared with that in wild-type mice, suggesting the compensatory effect of nNOS. Hence, eNOS(-/-) nNOS(-/-) mice were generated, underwent CA induction and confirmed that eNOS(-/-) nNOS(-/-) mice exhibited an increased incidence of CA formation accompanied by accelerated macrophage infiltration. These results suggested that the deficiency of eNOS could be compensated by nNOS upregulation in cerebral arteries and that the eNOS and nNOS complementarily had the protective role in CA formation. The results of this study will provide us with new insight about the mechanisms of CA formation and the functional redundancy between eNOS and nNOS in cerebral arteries.

Influence of hormone supplementation therapy on the incidence of denture stomatitis and on chemiluminescent activity of polymorphonuclear granulocytes in blood of menopausal-aged women

Background

Menopause is a health and social problem that affects a large number of women. Inadequate quantity of steroid hormones also impacts quality of the mucous membrane of the oral cavity. During menopausal age, many women wear removable prosthetic restorations in order to replace missing teeth. Such restorations may facilitate the development of inflammations in the surface of the oral cavity, referred to as denture stomatitis.

Objective

The aim of the study was to evaluate the influence of hormone supplementation therapy on the incidence of Candida-associated denture stomatitis and on the metabolic activity of polymorphonuclear granulocytes in peripheral blood of female patients.

Materials and methods

The study was conducted on a group of women in menopausal age, users of hormone replacement therapy and of removable prosthetic restorations. Female patients were subjected to a clinical study that included interviews and physical examinations. Laboratory microbiological examinations were completed on the basis of direct swabs collected from the mucous membrane of the oral cavity and from the surface of dentures. Metabolic activity of polymorphonuclear granulocytes in peripheral blood of female patients was evaluated by means of a chemiluminescence test.

Results

Candida-associated denture stomatitis observed was characterized by a strong growth of fungi and a lower chemiluminescent activity of neutrophils in blood of female patients undergoing hormone supplementation therapy.

Conclusions

Patients using hormone supplementation therapy and removable prosthetic restorations constitute a high-risk group for Candida infections and inflammations of the mucous membrane of the oral cavity; thus they should remain under constant dental control.

Estrogen-induced apoptosis of breast epithelial cells is blocked by NO/cGMP and mediated by extranuclear estrogen receptors

Estrogen action, via both nuclear and extranuclear estrogen receptors (ERs), induces a variety of cellular signals that are prosurvival or proliferative, whereas nitric oxide (NO) can inhibit apoptosis via caspase S-nitrosylation and via activation of soluble guanylyl cyclase to produce cGMP. The action of 17β-estradiol (E(2)) at ER is known to elicit NO signaling via activation of NO synthase (NOS) in many tissues. The MCF-10A nontumorigenic, mammary epithelial cell line is genetically stable and insensitive to estrogenic proliferation. In this cell line, estrogens or NOS inhibitors alone had no significant effect, whereas in combination, apoptosis was induced rapidly in the absence of serum; the presence of inducible NOS was confirmed by proteomic analysis. The application of pharmacological agents determined that apoptosis was dependent upon NO/cGMP signaling via cyclic GMP (cGMP)-dependent protein kinase and could be replicated by inhibition of the phosphatidylinositol 3 kinase/serine-threonine kinase pathway prior to addition of E(2). Apoptosis was confirmed by nuclear staining and increased caspase-3 activity in E(2) + NOS inhibitor-treated cells. Apoptosis was partially inhibited by a pure ER antagonist and replicated by agonists selective for extranuclear ER. Cells were rescued from E(2)-induced apoptosis after NOS blockade, by NO-donors and cGMP pathway agonists; preincubation with NO donors was required. The NOS and ER status of breast cancer tissues is significant in etiology, prognosis, and therapy. In this study, apoptosis of preneoplastic mammary epithelial cells was triggered by estrogens via a rapid, extranuclear ER-mediated response, after removal of an antiapoptotic NO/cGMP/cGMP-dependent protein kinase signal.

Periosteal microcirculatory action of chronic estrogen supplementation in osteoporotic rats challenged with tourniquet ischemia

AIMS

Transient ischemia of osteoporotic bones during elective orthopedic surgery or fracture repair carries risks for serious complications, and estrogen loss or replacement has a potential to influence ischemia-reperfusion-induced inflammatory activation. To clarify this, we investigated the periosteal inflammatory changes in a clinically relevant time frame in ovariectomized rats, an experimental model of postmenopausal bone loss. Furthermore, the effects of chronic estrogen supplementation on the postischemic local and systemic inflammatory reactions were assessed.

MAIN METHODS

Bilateral ovariectomy or sham operation was performed in 3-month-old female Sprague-Dawley rats. Five months later, estrogen replacement therapy with 17β-estradiol (20 μg(-1) kg(-1) day(-1)) or vehicle treatment was initiated. The microcirculatory inflammatory consequences of 60-min total hindlimb ischemia followed by 180-min reperfusion were examined 11 months after ovariectomy and were compared with those in 3-month-old animals.

KEY FINDINGS

The osteoporosis that developed 5 months after ovariectomy was significantly ameliorated by estrogen replacement therapy. Both in ovariectomized and in non-ovariectomized animals, ischemia-reperfusion elevated the neutrophil adherence ~3-fold in the postcapillary venules of the periosteum (intravital microscopy), with an ~50-60% increase in intravascular neutrophil activation (CD11b; FACS analysis), an enhanced TNF-α release (ELISA) and periosteal expression of ICAM-1 (the endothelial ligand of CD11b; immunohistochemistry). Exogenous 17β-estradiol considerably reduced TNF-α release and the number of neutrophil-endothelial interactions in the periosteum, without affecting the CD11b and ICAM-1 expression changes.

SIGNIFICANCE

Osteoporosis itself does not increase the magnitude of the limb ischemia-reperfusion-associated periosteal inflammatory reaction. Chronic estrogen supplementation, however, reverses osteoporosis and significantly ameliorates the microcirculatory consequences of transient ischemia.

Sex differences in destructive periodontal disease: exploring the biologic basis

BACKGROUND

Epidemiologic studies provide broad-based evidence that men are at greater risk for developing destructive periodontal disease than women, even after adjusting for behavioral and environmental factors, such as oral hygiene practice and smoking. What requires clarification, however, is whether sex-specific differences in immune function provide a plausible biologic basis for a sexual dimorphism in susceptibility to destructive periodontal disease. This review examines evidence that might provide an underlying biologic basis for a sexual dimorphism in the prevalence and severity of destructive periodontal disease.

METHODS

A narrative review of the literature related to sexual dimorphism in pathogen-mediated inflammatory diseases and immune response was retrieved from searches of computerized databases (MEDLINE, PubMed, and SCOPUS).

RESULTS

Sex steroids exert profound effects on multiple immunologic parameters regulating both the amplification and resolution of inflammation. Strong evidence exists for sexual dimorphisms in immune function, involving both innate and acquired immunity. Injury and infection have been associated with higher levels of inflammatory cytokines, including interleukin-1β and tumor necrosis factor-α, in men than women, paralleling observed sex-specific differences in periodontitis.

CONCLUSION

Differential gene regulation, particularly in sex steroid-responsive genes, may contribute to a sexual dimorphism in susceptibility to destructive periodontal disease.

Sex hormones and autoimmunity

Autoimmune diseases occur more in women than in men, and this may be attributable to the role of estrogens. Androgens promote autoimmune diseases with a profile of type 1 cytokines, such as rheumatoid arthritis, whereas estrogens promote autoimmune diseases with a type 2 cytokine profile, like systemic lupus erythematosus. Both androgens and estrogens regulate the Th1/Th2 balance. Type 1 autoimmune diseases are improved when decrease type 1 cytokines (i.e. during fasting), or when there is a rise in type 2 cytokines (increased estrogens, as in pregnancy). Type 2 autoimmune diseases improve when type 2 cytokines are diminished (decreased estrogen, as in post-partum period) or when type 1 response is stimulated.

Sex steroids as inflammatory regulators

It is becoming increasingly clear that endogenous sex steroids are key players in a range of inflammatory contexts. Androgens and estrogens have been shown to have a profound influence on the function of inflammatory cells including macrophages and on the secretion and activation of a range of plasma-borne inflammatory mediators. The menopause and polymorphisms in estrogen receptor genes have separately been shown to affect the incidence of a range of inflammatory disorders. Sex steroids themselves have been shown to be protective in certain conditions; harmful in others. This review will summarize their documented effects on inflammatory processes, with particular focus on two areas that have received much recent attention: the antiatherosclerotic properties of estrogens in females and the wound healing effects of sex steroids.

Protective actions of estrogen on angiotensin II-induced hypertension: role of central nitric oxide

The present study tested the hypotheses that 1) nitric oxide (NO) is involved in attenuated responses to ANG II in female mice, and 2) there is differential expression of neuronal NO synthase (nNOS) in the subfornical organ (SFO) and paraventricular nucleus (PVN) in response to systemic infusions of ANG II in males vs. females. Aortic blood pressure (BP) was measured in conscious mice with telemetry implants. N(G)-nitro-l-arginine methyl ester (l-NAME; 100 microg x kg(.-1)day(-1)), an inhibitor of NOS, was administrated into the lateral cerebral ventricle for 14 days before and during ANG II pump implantation. Central infusion of l-NAME augmented the pressor effects of systemic ANG II in females (Delta21.5 + or - 2.2 vs. Delta9.2 + or - 1.5 mmHg) but not in males (Delta29.4 + or - 2.5 vs. Delta30.1 + or - 2.5 mmHg). Central administration of N(5)-(1-imino-3-butenyl)-l-ornithine (l-VNIO), a selective nNOS inhibitor, also significantly potentiated the increase in BP induced by ANG II in females (Delta17.5 + or - 3.2 vs. Delta9.2 + or - 1.5 mmHg). In gonadectomized mice, central l-NAME infusion did not affect the pressor response to ANG II in either males or females. Ganglionic blockade after ANG II infusion resulted in a greater reduction in BP in central l-NAME- or l-VNIO-treated females compared with control females. Western blot analysis of nNOS protein expression indicated that levels were approximately 12-fold higher in both the SFO and PVN of intact females compared with those in intact males. Seven days of ANG II treatment resulted in a further increase in nNOS protein expression only in intact females (PVN, to approximately 51-fold). Immunohistochemical studies revealed colocalization of nNOS and estrogen receptors in the SFO and PVN. These results suggest that NO attenuates the increase in BP induced by ANG II through reduced sympathetic outflow in females and that increased nNOS protein expression associated with the presence of female sex hormones plays a protective role against ANG II-induced hypertension in female mice.

The X-files in immunity: sex-based differences predispose immune responses

Sex-based differences in immune responses can influence the susceptibility to autoimmune and infectious diseases and the efficacy of therapeutic drugs. In this Perspective, Eleanor Fish discusses factors, such as X-linked genes, hormones and societal context, that underlie disparate immune responses in men and women.

Despite accumulating evidence in support of sex-based differences in innate and adaptive immune responses, in the susceptibility to infectious diseases and in the prevalence of autoimmune diseases, health research and clinical practice do not address these distinctions, and most research studies of immune responses do not stratify by sex. X-linked genes, hormones and societal context are among the many factors that contribute to disparate immune responses in males and females. It is crucial to address sex-based differences in disease pathogenesis and in the pharmacokinetics and pharmacodynamics of therapeutic medications to provide optimal disease management for both sexes.

ClC-3 and IClswell are required for normal neutrophil chemotaxis and shape change

Polymorphonuclear leukocytes undergo directed movement to sites of infection, a complex process known as chemotaxis. Extension of the polymorphonuclear leukocyte (PMN) leading edge toward a chemoattractant in association with uropod retraction must involve a coordinated increase/decrease in membrane, redistribution of cell volume, or both. Deficits in PMN phagocytosis and trans-endothelial migration, both highly motile PMN functions, suggested that the anion transporters, ClC-3 and ICl(swell), are involved in cell motility and shape change ( Moreland, J. G., Davis, A. P., Bailey, G., Nauseef, W. M., and Lamb, F. S. (2006) J. Biol. Chem. 281, 12277-12288 ). We hypothesized that ClC-3 and ICl(swell) are required for normal PMN chemotaxis through regulation of cell volume and shape change. Using complementary chemotaxis assays, EZ-TAXIScantrade mark and dynamic imaging analysis software, we analyzed the directed cell movement and morphology of PMNs lacking normal anion transporter function. Murine Clcn3(-/-) PMNs and human PMNs treated with anion transporter inhibitors demonstrated impaired chemotaxis in response to formyl peptide. This included decreased cell velocity and failure to undergo normal cycles of elongation and retraction. Impaired chemotaxis was not due to a diminished number of formyl peptide receptors in either murine or human PMNs, as measured by flow cytometry. Murine Clcn3(-/-) and Clcn3(+/+) PMNs demonstrated a similar regulatory volume decrease, indicating that the ICl(swell) response to hypotonic challenge was intact in these cells. We further demonstrated that ICl(swell) is essential for shape change during human PMN chemotaxis. We speculate that ClC-3 and ICl(swell) have unique roles in regulation of PMN chemotaxis; ICl(swell) through direct effects on PMN volume and ClC-3 through regulation of ICl(swell).

Redox features of the cell: a gender perspective

Reactive oxygen and nitrogen species have been implicated in diverse subcellular activities, including cell proliferation,differentiation and, in some instances, cell injury and death. The implications of reactive species inhuman pathology have also been studied in detail. However, although the role of free radicals in the pathogenesis of human diseases has been extensively analyzed in different systems (i.e., in vitro, ex vivo, and in vivo),it is still far from elucidated. In particular, the possible role of gender 4 differences in human pathophysiology associated with reactive species is a promising new field of investigation. Although the complex scenario this presents is still incomplete, important gender-associated "redox features" of cells have already been described in the literature. Here we summarize the different aspects of redox-associated molecules and enzymes in regard to gender differences in terms of the intracellular production and biochemical activity of reactive species. These are often associated with the pathogenetic mechanisms underlying several human morbidities(e.g., degenerative diseases) and can represent a specific target for new pharmacologic strategies. Gender differences may thus pose an important challenge for future studies aimed at the clinical management of diseases characterized by a redox imbalance.

Effects of Menstrual Cycle Status and Gender on Human Neutrophil Phenotype

PROBLEM

The effects of gender and fluctuating ovarian hormones on neutrophil phenotype have yet to be characterized.

METHOD OF STUDY

Neutrophils from females at days 7, 14, 21, and 28 of the menstrual cycle were analyzed by flow cytometry for surface receptor, granule protein, and intracellular cytokine expression. Comparisons were made to neutrophils from males isolated at 7-day intervals during 1 month.

RESULTS

Decreased MMP-9 and TNF-alpha expression by neutrophils from females was observed during the periovulatory period. Comparing the genders, cells from females during the periovulatory period expressed less CD11b and CD18 than those from males. CXCR1 surface levels were higher on neutrophils from female donors.

CONCLUSIONS

Neutrophil phenotype varies minimally during the menstrual cycle and between the genders. Our data provide support for a potential anti-inflammatory effect of ovarian hormones on neutrophils.

SEX HORMONES AND THE CARDIOVASCULAR SYSTEM: EFFECTS ON ARTERIAL FUNCTION IN WOMEN

1. It has long been hypothesized that oestrogen may be cardioprotective. This hypothesis is supported by diverse and comprehensive mechanistic studies in animals and humans. Consistently, in observational studies, oestrogen use in post-menopausal women significantly reduced cardiovascular disease. Contrastingly, large interventional trials focusing on chronic disease prevention in older post-menopausal women have suggested neutral (oestrogen alone) or adverse (combined oestrogen/progestin preparations) cardiovascular effects. 2. The negative initial interpretation and extrapolation of the early randomized, controlled interventional trials, primarily the Women's Health Initiative, has recently been theoretically reconciled with the positive mechanistic and observational studies. As a new interventional literature emerges, it has been suggested that if oestrogen is used from menopause onwards it is likely to be protective, but if instituted after endothelial damage has occurred in an oestrogen-deficient post-menopausal state, the beneficial vessel wall effects are not observed and the procoagulant effects result in overall increased cardiovascular risk. 3. The present article reviews the literature on arterial function and oestrogen use in the setting of the early endothelial protection theory. This theory is generally supported by the data on oestrogen effects on arterial function. In general, in studies of premenopausal women the effects of oestrogen were positive, with similar benefits noted if oestrogen was used early after menopause. However, where hormone therapy was commenced some years after menopause, the beneficial effects on arterial function were not observed. In clinical practice, hormone therapy is primarily used at menopause for the treatment of menopausal symptoms. The data on arterial function reviewed herein, along with emerging interventional human studies, suggest that the cardiovascular effects of this practice are not adverse.

Estrogen-induced generation of reactive oxygen and nitrogen species, gene damage, and estrogen-dependent cancers

In addition to the direct effect of estrogen on mitochondria and the redox cycling of catechol estrogen, estrogen-induced proinflammatory cytokines, such as interleukin-1 beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha), also generate reactive oxygen and nitrogen species (RO/NS). Different cellular signaling pathways may operate in response to varying levels of estrogen-induced RO/NS, leading to genotoxic damage, cell apoptosis, or cell growth. At high levels of RO/NS, cells receiving genotoxic insults, if not repaired, may engage the apoptotic pathways. There is increasing evidence supporting that estrogen-induced alterations in the genome of cells is produced by oxidative attack. Furthermore, ROS generated by estrogen exposure and/or active metabolites of estrogen in combination with receptor-mediated proliferation of genetically damaged cells may be involved in tumor development. This view is supported by the findings of DNA modifications produced in vitro or in vivo by natural and synthetic estrogens in the target organs of cancer both in experimental models and in humans. Interaction of estrogen-induced oxidants and estrogen metabolites with DNA was shown to generate mutations in genes. Cotreatment with an inhibitor of IL-1beta and TNF-alpha synthesis, pentoxifylline, decreased stilbene estrogen-induced levels of myeloperoxidase (MPO), 8-hydroxydeoxyguanosine formation, and gene mutations, and prevented stilbene estrogen-induced lesions. Stable MCF-7 clones overexpressing IL-1beta resulted in a high level of IL-1beta peptide secretion undergoing cell apoptosis, and an elevated level of p53 protein in response to high oxidative stress when compared to nontransfected cells, whereas MCF-7 clones overexpressing IL-1beta that resulted in a moderate level of IL-1beta secretion stimulated the clonal expansion of MCF-7 and TM3 cells. Estrogen-induced MCF-7 cell growth and cyclin D1 expression were suppressed by antioxidants and mitochondrial blockers. These studies support that in addition to ovarian estrogen-mediated ER signaling, mitogenic signals may also come from estrogen-induced RO/NS. Further validation of this concept that the concentration of the RO/NS within the cellular microenvironment determines its stimulatory or inhibitory growth signals as well as its genotoxic effects regulating the growth of estrogen-dependent tumors may result in novel preventive strategies.

Human Fallopian Tube Neutrophils – A Distinct Phenotype from Blood Neutrophils

PROBLEM

The role of neutrophils in the human Fallopian tube (FT) is unknown. In order to provide insights into their functions in the FT, we systematically compared neutrophils from normal FT and peripheral blood (PB).

METHOD OF STUDY

Flow cytometric analysis of surface receptors, granule proteins, and intracellular cytokines expressed by neutrophils from enzymatically dispersed FT and PB was performed.

RESULTS

Fallopian tube neutrophils expressed significantly higher levels of CD64, human class II histocompatibility antigen DR (HLA-DR), gamma-interferon, and vascular endothelial growth factor than those from PB. Fewer FT neutrophils expressed IL-8 receptors compared to PB, while more expressed the receptor for the bacterial-derived chemoattractant formyl-Met-Leu-Phe (fMLP). The number of FT neutrophils containing the granule proteins matrix metalloproteinase-9, lactoferrin, and myeloperoxidase was decreased versus PB.

CONCLUSION

Fallopian tube neutrophils exhibit a phenotype distinct from PB neutrophils, suggesting functional activation of innate immune defense in the female reproductive tract as well as a potential role in maintaining normal FT physiology.

Estrogen therapy and thrombotic risk

Post-menopausal hormone therapy increases the risk for venous thrombosis, and possibly myocardial infarction (MI) and ischemic stroke. However, most women using hormone therapy do not suffer thrombosis, and to date our ability to identify women at risk is limited. Thrombosis, arterial or venous, has 2 requisites: a vascular anomaly and a response of the hemostasis system to the anomaly. Consequently, experimental approaches to understand the pathophysiology of thrombosis require definition of vascular anatomy and function as well as characteristics of the blood within the context of genetic background, lifestyle choices and environmental exposures, which influence gene expression. Defining interactions among factors that affect individual propensity to thrombosis will allow physicians to better identify at-risk individuals, for example a woman contemplating estrogen therapy for symptoms of menopause, and prevent adverse thrombotic events.

Anion channels, including ClC-3, are required for normal neutrophil oxidative function, phagocytosis, and transendothelial migration

NADPH oxidase activity, phagocytosis, and cell migration are essential functions of polymorphonuclear leukocytes (PMNs) in host defense. The cytoskeletal reorganization necessary to perform these functions has been extensively studied, but the role of cell volume regulation, which is likely dependent upon anion channels, has not been defined. Mice lacking the anion channel ClC-3 (Clcn3(-/-)) died from presumed sepsis following intravascular catheter placement, whereas Clcn3(+/+) littermates survived. We hypothesized that ClC-3 has a critical role in host defense and reasoned that PMN function would be compromised in these mice. Clcn3(-/-) PMNs displayed markedly reduced NADPH oxidase activity in response to opsonized zymosan and modestly reduced activity after phorbol 12-myristate 13-acetate. Human PMNs treated with the anion channel inhibitors niflumic acid or 5-nitro-2-(3-phenylpropylamino)benzoic acid had a very similar defect. ClC-3 protein was detected in the secretory vesicles and secondary granules of resting PMNs and was up-regulated to the phagosomal membrane. Clcn3(-/-) PMNs and human PMNs lacking normal anion channel function both exhibited reduced uptake of opsonized zymosan at 1, 5, and 10 min in a synchronized phagocytosis assay. Niflumic acid-treated PMNs also had impaired transendothelial migration in vitro, whereas migration in vivo was not altered in Clcn3(-/-) PMNs. Selective inhibition of the swelling-activated chloride channel with tamoxifen profoundly reduced PMN migration but had no effect on NADPH oxidase activity. In summary, PMNs lacking normal anion channel function exhibited reduced NADPH oxidase activity, diminished phagocytosis, and impaired migration. ClC-3 was specifically involved in the respiratory burst and phagocytosis.