Testosterone reduces macrophage expression in the mouse of toll-like receptor 4, a trigger for inflammation and innate immunity

Testosterone Disorders and Male Hypogonadism in Kidney Disease

Chronic kidney disease (CKD) causes substantial alterations in the male endocrine system, which affect puberty, libido, and sexual function. A major effect of CKD is a reduction in testosterone levels because of both primary and hypogonadotrophic hypogonadism. In addition to impairment of pubertal growth and sexual maturation in children with CKD, clinical evidence suggests that uremic hypogonadism strongly contributes to several CKD complications, including erectile dysfunction, muscle wasting and frailty, anemia, decreased bone mineralization, depression, and cognitive impairment. This review focuses on a reappraisal of the physiologic role of testosterone, with an emphasis on the hypogonadal condition linked to CKD and its complications.

Sex effects in pyelonephritis

Urinary tract infections (UTIs) are generally considered a disease of women. However, UTIs affect females throughout the lifespan, and certain male populations (including infants and elderly men) are also susceptible. Epidemiologically, pyelonephritis is more common in women but carries increased morbidity when it does occur in men. Among children, high-grade vesicoureteral reflux is a primary risk factor for upper-tract UTI in both sexes. However, among young infants with UTI, girls are outnumbered by boys; risk factors include posterior urethral valves and lack of circumcision. Recent advances in mouse models of UTI reveal sex differences in innate responses to UTI, which vary somewhat depending on the system used. Moreover, male mice and androgenized female mice suffer worse outcomes in experimental pyelonephritis; evidence suggests that androgen exposure may suppress innate control of infection in the urinary tract, but additional androgen effects, as well as non-hormonal sex effects, may yet be specified. Among other intriguing directions, recent experiments raise the hypothesis that the postnatal testosterone surge that occurs in male infants may represent an additional factor driving the higher incidence of UTI in males under 6 months of age. Ongoing work in contemporary models will further illuminate sex- and sex-hormone-specific effects on UTI pathogenesis and immune responses.

Physiological and metabolic approach of plastic additive effects: Immune cells responses

Human and wildlife are continually exposed to a wide range of compounds and substances, which reach the body through the air, water, food, or personal care products. Plasticizers are compounds added to plastics and can be released to the environment under certain conditions. Toxicological studies have concluded that plasticizers, phthalates, and bisphenols are endocrine disruptors, alter the endocrine system and functioning of the immune system and metabolic process. A functional immune response indicates favourable living conditions for an organism; conversely, a weak immune response could reveal a degraded environment that requires organisms to adapt. There is growing concern about the presence of plastic debris in the environment. In this review, the current knowledge of the action of plasticizers on leukocyte cells will be itemized. We also point out critically the role of some nuclear and membrane receptors as key players in the action of plasticizers on cells possess immune function. We discuss the role of erythrocytes within the immune responses and the alteration caused by plasticizers. Finally, we highlight data evidencing mitochondrial dysfunctions triggered by plasticizing toxic action, which can lead to immunosuppression.

Neuroprotection of dihydrotestosterone via suppression of the toll-like receptor 4/nuclear factor-kappa B signaling pathway in high glucose-induced BV-2 microglia inflammatory responses

Hyperglycemia is considered to induce neuronal apoptosis via activating microglia inflammatory responses, thus involving in the development and progression of diabetic encephalopathy and neurodegenerative disorders. Increasing evidences suggest that androgen exerts neuroprotective functions including antiapoptosis, anti-inflammation and antioxidative stress. In this study, we investigate the anti-inflammatory role of dihydrotestosterone (DHT) in high glucose (HG)-induced neuroinflammatory response in BV-2 microglia. Our results revealed that DHT significantly inhibited HG-induced production of nitric oxide and prostaglandin E2 through suppressing the expression of corresponding regulatory enzymes - inducible NO synthase and cyclooxygenase-2. Also, DHT inhibited HG-induced expression of TNF-α and IL-1β. Moreover, DHT suppressed the toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) signaling pathway. Furthermore, when SH-SY5Y neurons were cultured in HG-treated BV-2 microglial supernatant, DHT pretreatment significantly increased neuronal survival, indicating the neuroprotective role of DHT. Collectively, these results suggest that DHT could protect SH-SY5Y neurons from HG-mediated BV-2 microglia inflammatory damage through inhibiting TLR4/NF-κB signaling, suggesting that maintenance of androgen level in brain might have potential benefit in neurodegenerative diseases, especially in diabetes patients combined with cognitive disorders.

Amyotrophic Lateral Sclerosis Survival Associates With Neutrophils in a Sex-specific Manner

Objective

To determine whether neutrophils contribute to amyotrophic lateral sclerosis (ALS) progression, we tested the association of baseline neutrophil count on ALS survival, whether the effect was sex specific, and whether neutrophils accumulate in the spinal cord.

Methods

A prospective cohort study was conducted between June 22, 2011, and October 30, 2019. Blood leukocytes were isolated from ALS participants and neutrophil levels assessed by flow cytometry. Participant survival outcomes were analyzed by groups (<2 × 10⁶, 2–4 × 10⁶, and >4 × 10⁶ neutrophils/mL) with adjustments for relevant ALS covariates and by sex. Neutrophil levels were assessed from CNS tissue from a subset of participants.

Results

A total of 269 participants with ALS within 2 years of an ALS diagnosis were included. Participants with baseline neutrophil counts over 4 × 10⁶/mL had a 2.1 times higher mortality rate than those with a neutrophil count lower than 2 × 10⁶/mL (95% CI: 1.3–3.5, p = 0.004) when adjusting for age, sex, and other covariates. This effect was more pronounced in females, with a hazard ratio of 3.8 (95% CI: 1.8–8.2, p = 0.001) in the >4 × 10⁶/mL vs <2 × 10⁶/mL group. Furthermore, ALS participants (n = 8) had increased neutrophils in cervical (p = 0.049) and thoracic (p = 0.022) spinal cord segments compared with control participants (n = 8).

Conclusions

Higher neutrophil counts early in ALS associate with a shorter survival in female participants. Furthermore, neutrophils accumulate in ALS spinal cord supporting a pathophysiologic correlate. These data justify the consideration of immunity and sex for personalized therapeutic development in ALS.

Classification of Evidence

This study provides Class III evidence that in female participants with ALS, higher baseline neutrophil counts are associated with shorter survival.

Sexual Dimorphism in Innate Immunity: The Role of Sex Hormones and Epigenetics

Sexual dimorphism refers to differences between biological sexes that extend beyond sexual characteristics. In humans, sexual dimorphism in the immune response has been well demonstrated, with females exhibiting lower infection rates than males for a variety of bacterial, viral, and parasitic pathogens. There is also a substantially increased incidence of autoimmune disease in females compared to males. Together, these trends indicate that females have a heightened immune reactogenicity to both self and non-self-molecular patterns. However, the molecular mechanisms driving the sexually dimorphic immune response are not fully understood. The female sex hormones estrogen and progesterone, as well as the male androgens, such as testosterone, elicit direct effects on the function and inflammatory capacity of immune cells. Several studies have identified a sex-specific transcriptome and methylome, independent of the well-described phenomenon of X-chromosome inactivation, suggesting that sexual dimorphism also occurs at the epigenetic level. Moreover, distinct alterations to the transcriptome and epigenetic landscape occur in synchrony with periods of hormonal change, such as puberty, pregnancy, menopause, and exogenous hormone therapy. These changes are also mirrored by changes in immune cell function. This review will outline the evidence for sex hormones and pregnancy-associated hormones as drivers of epigenetic change, and how this may contribute to the sexual dimorphism. Determining the effects of sex hormones on innate immune function is important for understanding sexually dimorphic autoimmune diseases, sex-specific responses to pathogens and vaccines, and how innate immunity is altered during periods of hormonal change (endogenous or exogenous).

Sex-specific differences in peripheral blood leukocyte transcriptional response to LPS are enriched for HLA region and X chromosome genes

Sex-specific differences in prevalence are well documented for many common, complex diseases, especially for immune-mediated diseases, yet the precise mechanisms through which factors associated with biological sex exert their effects throughout life are not well understood. We interrogated sex-specific transcriptional responses of peripheral blood leukocytes (PBLs) to innate immune stimulation by lipopolysaccharide (LPS) in 46 male and 66 female members of the Hutterite community, who practice a communal lifestyle. We identified 1217 autosomal and 54 X-linked genes with sex-specific responses to LPS, as well as 71 autosomal and one X-linked sex-specific expression quantitative trait loci (eQTLs). Despite a similar proportion of the 15 HLA genes responding to LPS compared to all expressed autosomal genes, there was a significant over-representation of genes with sex by treatment interactions among HLA genes. We also observed an enrichment of sex-specific differentially expressed genes in response to LPS for X-linked genes compared to autosomal genes, suggesting that HLA and X-linked genes may disproportionately contribute to sex disparities in risk for immune-mediated diseases.

Gland Macrophages: Reciprocal Control and Function within Their Niche

The human body contains dozens of endocrine and exocrine glands, which regulate physiological processes by secreting hormones and other factors. Glands can be subdivided into contiguous tissue modules, each consisting of an interdependent network of cells that together perform particular tissue functions. Among those cells are macrophages, a diverse type of immune cells endowed with trophic functions. In this review, we discuss recent findings on how resident macrophages support tissue modules within glands via the creation of mutually beneficial cell-cell circuits. A better comprehension of gland macrophage function and local control within their niche is essential to achieve a refined understanding of gland physiology in homeostasis and disease.

Neuroprotective Effects of Testosterone in Male Wobbler Mouse, a Model of Amyotrophic Lateral Sclerosis

Patients suffering of amyotrophic lateral sclerosis (ALS) present motoneuron degeneration leading to muscle atrophy, dysphagia, and dysarthria. The Wobbler mouse, an animal model of ALS, shows a selective loss of motoneurons, astrocytosis, and microgliosis in the spinal cord. The incidence of ALS is greater in men; however, it increases in women after menopause, suggesting a role of sex steroids in ALS. Testosterone is a complex steroid that exerts its effects directly via androgen (AR) or Sigma-1 receptors and indirectly via estrogen receptors (ER) after aromatization into estradiol. Its reduced-metabolite 5α-dihydrotestosterone acts via AR. This study analyzed the effects of testosterone in male symptomatic Wobblers. Controls or Wobblers received empty or testosterone-filled silastic tubes for 2 months. The cervical spinal cord from testosterone-treated Wobblers showed (1) similar androgen levels to untreated control and (2) increased levels of testosterone, and its 5α-reduced metabolites, 5α- dihydrotestosterone, and 3β-androstanediol, but (3) undetectable levels of estradiol compared to untreated Wobblers. Testosterone-treated controls showed comparable steroid concentrations to its untreated counterpart. In testosterone- treated Wobblers a reduction of AR, ERα, and aromatase and high levels of Sigma-1 receptor mRNAs was demonstrated. Testosterone treatment increased ChAT immunoreactivity and the antiinflammatory mediator TGFβ, while it lessened vacuolated motoneurons, GFAP+ astrogliosis, the density of IBA1+ microgliosis, proinflammatory mediators, and oxidative/nitrosative stress. Clinically, testosterone treatment in Wobblers slowed the progression of paw atrophy and improved rotarod performance. Collectively, our findings indicate an antiinflammatory and protective effect of testosterone in the degenerating spinal cord. These results coincided with a high concentration of androgen-reduced derivatives after testosterone treatment suggesting that the steroid profile may have a beneficial role on disease progression.

Sex differences in COVID-19: candidate pathways, genetics of ACE2, and sex hormones

Biological sex is increasingly recognized as a critical determinant of health and disease, particularly relevant to the topical COVID-19 pandemic caused by the SARS-CoV-2 coronavirus. Epidemiological data and observational reports from both the original SARS epidemic and the most recent COVID-19 pandemic have a common feature: males are more likely to exhibit enhanced disease severity and mortality than females. Sex differences in cardiovascular disease and COVID-19 share mechanistic foundations, namely, the involvement of both the innate immune system and the canonical renin-angiotensin system (RAS). Immunological differences suggest that females mount a rapid and aggressive innate immune response, and the attenuated antiviral response in males may confer enhanced susceptibility to severe disease. Furthermore, the angiotensin-converting enzyme 2 (ACE2) is involved in disease pathogenesis in cardiovascular disease and COVID-19, either to serve as a protective mechanism by deactivating the RAS or as the receptor for viral entry, respectively. Loss of membrane ACE2 and a corresponding increase in plasma ACE2 are associated with worsened cardiovascular disease outcomes, a mechanism attributed to a disintegrin and metalloproteinase (ADAM17). SARS-CoV-2 infection also leads to ADAM17 activation, a positive feedback cycle that exacerbates ACE2 loss. Therefore, the relationship between cardiovascular disease and COVID-19 is critically dependent on the loss of membrane ACE2 by ADAM17-mediated proteolytic cleavage. This article explores potential mechanisms involved in COVID-19 that may contribute to sex-specific susceptibility focusing on the innate immune system and the RAS, namely, genetics and sex hormones. Finally, we highlight here the added challenges of gender in the COVID-19 pandemic.

Lowered Serum Testosterone Concentration Is Associated With Enhanced Inflammation and Worsened Lipid Profile in Men

The negative relationship between testosterone and inflammatory cytokines has been reported for decades, although the exact mechanisms of their interactions are still not clear. At the same time, little is known about the relation between androgens and acute phase proteins. Therefore, in this investigation, we aimed to study the relationship between androgen status and inflammatory acute phase reactants in a group of men using multi-linear regression analysis. Venous blood samples were taken from 149 men ranging in age from 18 to 77 years. Gonadal androgens [testosterone (T) and free testosterone (fT)], acute phase reactants [C-reactive protein (CRP), ferritin (FER), alpha-1-acid glycoprotein (AAG), and interleukin-6 (IL-6)], cortisol (C), and lipid profile concentrations were determined. It was demonstrated that the markers of T and fT were negatively correlated with all acute phase proteins (CRP, FER, and AAG; p < 0.02) and the blood lipid profile [total cholesterol (TC), low-density lipoprotein (LDL), and triglycerides (TG); p < 0.03]. Multivariate analysis showed that T, fT, and the fT/C ratio were inversely correlated with the CRP, AAG, and FER concentrations independently of age and blood lipids. When adjustment for BMI was made, T, fT, and the fT/C ratio were negatively correlated with the AAG concentrations only. In addition, it was demonstrated that gonadal androgens were positively correlated with physical activity level (p < 0.01). We have concluded that a lowered serum T concentration may promote inflammatory processes independently of adipose tissue and age through a reduced inhibition of inflammatory cytokine synthesis, which leads to enhanced acute phase protein production. Therefore, a low serum T concentration appears to be an independent risk factor in the development of atherosclerosis and cardiovascular diseases. Moreover, the positive correlation between testosterone and physical activity level suggests that exercise training attenuates the age-related decrease in gonadal androgens and, in this way, may reduce the enhancement of systemic low-grade inflammation in aging men.

Systemic inflammation and symptomatology in patients with prostate cancer treated with androgen deprivation therapy: Preliminary findings

BACKGROUND

Increases in fatigue, depressive symptomatology, and cognitive impairment are common after the initiation of androgen deprivation therapy (ADT) for prostate cancer. To date, no studies have examined the potential role of inflammation in the development of these symptoms in ADT recipients. The goal of the current study was to examine circulating markers of inflammation as potential mediators of change in fatigue, depressive symptomatology, and cognitive impairment related to the receipt of ADT.

METHODS

Patients treated with ADT for prostate cancer (ADT+; n = 47) were assessed around the time of the initiation of ADT and 6 and 12 months later. An age- and education-matched group of men without a history of cancer (CA-; n = 82) was assessed at comparable time points. Fatigue, depressive symptomatology, and cognitive impairment were assessed with the Fatigue Symptom Inventory, the Center for Epidemiological Studies Depression Scale, and a battery of neuropsychological tests, respectively. Circulating markers of inflammation included interleukin 1 receptor antagonist (IL-1RA), interleukin 6 (IL-6), soluble tumor necrosis factor receptor II (sTNF-RII), and C-reactive protein (CRP).

RESULTS

Fatigue, depressive symptomatology, and serum IL-6 increased significantly over time in the ADT+ group versus the CA- group; rates of cognitive impairment also changed significantly between the groups. No significant changes in IL-1RA, sTNF-RII, or CRP over time were detected. Treatment-related increases in IL-6 were associated with worsening fatigue but not depressive symptomatology or cognitive impairment.

CONCLUSIONS

Results of this preliminary study suggest that increases in circulating IL-6, perhaps due to testosterone inhibition, may play a role in fatigue secondary to receipt of ADT. Additional research is needed to determine whether interventions to reduce circulating inflammation improve fatigue in this population.

Sex differences in COVID-19: candidate pathways, genetics of ACE2, and sex hormones

Biological sex is increasingly recognized as a critical determinant of health and disease, particularly relevant to the topical COVID-19 pandemic caused by the SARS-CoV-2 coronavirus. Epidemiological data and observational reports from both the original SARS epidemic and the most recent COVID-19 pandemic have a common feature: males are more likely to exhibit enhanced disease severity and mortality than females. Sex differences in cardiovascular disease and COVID-19 share mechanistic foundations, namely, the involvement of both the innate immune system and the canonical renin-angiotensin system (RAS). Immunological differences suggest that females mount a rapid and aggressive innate immune response, and the attenuated antiviral response in males may confer enhanced susceptibility to severe disease. Furthermore, the angiotensin-converting enzyme 2 (ACE2) is involved in disease pathogenesis in cardiovascular disease and COVID-19, either to serve as a protective mechanism by deactivating the RAS or as the receptor for viral entry, respectively. Loss of membrane ACE2 and a corresponding increase in plasma ACE2 are associated with worsened cardiovascular disease outcomes, a mechanism attributed to a disintegrin and metalloproteinase (ADAM17). SARS-CoV-2 infection also leads to ADAM17 activation, a positive feedback cycle that exacerbates ACE2 loss. Therefore, the relationship between cardiovascular disease and COVID-19 is critically dependent on the loss of membrane ACE2 by ADAM17-mediated proteolytic cleavage. This article explores potential mechanisms involved in COVID-19 that may contribute to sex-specific susceptibility focusing on the innate immune system and the RAS, namely, genetics and sex hormones. Finally, we highlight here the added challenges of gender in the COVID-19 pandemic.

COVID-19 pandemic: Mechanistic approaches and gender vulnerabilities

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a highly pathogenic virus that causes coronavirus-19 disease (COVID-19), a severe respiratory damaging syndrome with serious health complications worldwide. SARS-CoV-2 was unfamilar before the epidemic started in Wuhan, China, in December 2019. COVID-19 is currently a pandemic influencing several countries worldwide. One of the mysteries of the new coronavirus is that it is deadlier for men than women with the male mortality rate is twice as high as that of females.

Exposure to hyperandrogen drives ovarian dysfunction and fibrosis by activating the NLRP3 inflammasome in mice

Hyperandrogenism is the main cause of infertility as a result of polycystic ovary syndrome (PCOS). Long-term and continuous exposure to hyperandrogen can cause follicular developmental disorders. Ovarian granulosa cells (GCs) are critical in shaping the follicular development. To clarify how excessive androgen suppresses folliculogenesis and ovulation, we constructed PCOS mice by implantation of a 35-d testosterone (T) continuous-release pellet. Ovarian toll-like receptor 4 (TLR4) expression and serum IL-6 and IL-1β levels were dramatically increased in T-treated mice. In addition, the expression of NLRP3 inflammasome in the ovary of T-treated mice suggests that pyroptosis may play an essential role in follicular dysfunction. Lipopolysaccharide (LPS) has been extensively studied for activating cells by binding to TLR4. In this study, we demonstrated that LPS-induced inflammation leads to activation of the NLRP3 inflammasome with consequent impacts on follicular dysfunction. Herein we showed that LPS treatment upregulated the expression of 3β-hydroxysteroid dehydrogenase (3β-HSD) and androgen receptor (AR), while suppressed follicle stimulating hormone receptor (FSHR) expression in vitro. Moreover, we overexpressed NLRP3 using nigericin or lentiviral particles in GCs. The protein and mRNA levels of pyroptotic factors were highly enhanced with NLRP3 overexpression. As expected, the expression of Cyp19α1, Cyp11α1, 3β-HSD and FSHR at both the protein and mRNA levels was also markedly increased with excessive NLRP3. After inhibiting NLRP3, dihydrotestosterone (DHT)-treated GCs demonstrated markedly decreased NLRP3, the inflammasome adapter protein ASC, C-terminal fragment of gasdermin D (GSDMD-C), AR and Cyp19α1 at the protein level. Furthermore, with NLRP3 overexpression, the expression of fibrotic factors in ovarian cells was dramatically increased, such as TGF-β, CTGF, α-SMA, β-catenin, collagen I and collagen IV. These findings suggest that hyperandrogen stimulates chronic low-grade inflammation in the ovary to activate the NLRP3 inflammasome, further inducing a series of pathologies including ovarian GC pyroptotic death, follicular dysfunction and ovarian interstitial cell fibrosis.

Molecular Mechanisms of Sex-Related Differences in Arthritis and Associated Pain

Clinical conditions leading to chronic pain show important sex-related differences in the prevalence, severity, and degree of functional disability. Decades of epidemiological and clinical studies have demonstrated that women are more sensitive to pain than men. Arthritis, including rheumatoid arthritis (RA) and osteoarthritis (OA), is much more prevalent in females and accounts for the majority of pain arising from musculoskeletal conditions. It is therefore important to understand the mechanisms governing sex-dependent differences in chronic pain, including arthritis pain. However, research into the mechanisms underlying the sex-related differences in arthritis-induced pain is still in its infancy due to the bias in biomedical research performed largely in male subjects and animals. In this review, we discuss current advances in both clinical and preclinical research regarding sex-related differences in the development or severity of arthritis and associated pain. In addition, sex-related differences in biological and molecular mechanisms underlying the pathogenesis of arthritis pain, elucidated based on clinical and preclinical findings, are reviewed.

Investigation into Possible Association of Oxandrolone and Heterotopic Ossification Following Burn Injury

Oxandrolone, a testosterone analog, is used to counteract the catabolic effects of burn injury. Recent animal studies suggest a possible hormonal association with heterotopic ossification (HO) development postburn. This work examines oxandrolone administration and HO development by exploring historical clinical data bridging the introduction of oxandrolone into clinical practice. Additionally, we examine associations between oxandrolone administration and HO in a standardized mouse model of burn/trauma-related HO. Acutely burned adults admitted between 2000 and 2014, survived through discharge, and had a HO risk factor of 7 or higher were selected for analysis from a single burn center. Oxandrolone administration, clinical and demographic data, and elbow HO were recorded and were analyzed with logistic regression. Associations of oxandrolone with HO were examined in a mouse model. Mice were administered oxandrolone or vehicle control following burn/tenotomy to examine any potential effect of oxandrolone on HO and were analyzed by Student's t test. Subjects who received oxandrolone had a higher incidence of elbow HO than those that did not receive oxandrolone. However, when controlling for oxandrolone administration, oxandrolone duration, postburn day oxandrolone initiation, HO risk score category, age, sex, race, burn size, and year of injury, there was no significant difference between rates of elbow HO between the two populations. In agreement with the review, in the mouse model, while there was a trend toward the oxandrolone group developing a greater volume of HO, this did not reach statistical significance.

Twenty-First Century Viral Pandemics: A Literature Review of Sexual Transmission and Fertility Implications in Men

INTRODUCTION

The 21st century has seen a series of viral pandemics that have collectively infected millions of individuals. To understand factors that may contribute to viral spread and address long-term health sequelae for survivors, it is important to review evidence regarding viral presence in semen, sexual transmission potential, and possible effects on fertility.

AIM

To review the current literature regarding the sexual transmissibility of recent viral pandemics and their effects on semen parameters and fertility. We review evidence for the following viruses: Ebola, Zika, West Nile, pandemic influenza, severe acute respiratory syndrome (SARS), and SARS-corona virus-2 (SARS-CoV-2).

METHODS

A literature search was conducted to identify relevant studies. Titles and abstracts were reviewed for relevance. References from identified articles were searched and included, if appropriate.

MAIN OUTCOME MEASURES

The main outcome measure of this study was reviewing of peer-reviewed literature.

RESULTS

Both the Ebola virus and Zika virus are present in semen, but only the Zika virus shows consistent evidence of sexual transmission. Current evidence does not support the presence of the West Nile virus, pandemic influenza, SARS, and SARS-CoV-2 in semen. The Zika virus appears to alter semen parameters in a way that diminishes fertility, but the effect is likely time limited. The West Nile virus and SARS have been associated with orchitis in a small number of case reports. Viruses that cause febrile illness, such as pandemic influenza, SARS, and SARS-CoV-2, are associated with decreased sperm count and motility and abnormal morphology. SARS and SARS-CoV-2 may interact with angiotensin-converting enzyme 2 receptors present in the testes, which could impact spermatogenesis.

CONCLUSIONS

We have reported the presence in semen, sexual transmission potential, and fertility side effects of recent viral pandemics. Overall, semen studies and fertility effects are highly understudied in viral pandemics, and rigorous study on these topics should be undertaken as novel pandemics emerge. Payne K, Kenny P, Scovell JM, et al. Twenty-First Century Viral Pandemics: A Literature Review of Sexual Transmission and Fertility Implications for Men. Sex Med Rev 2020;8:518-530.

Testicular immune cell populations and macrophage polarisation in adult male mice and the influence of altered activin A levels

Detailed morphological characterization of testicular leukocytes in the adult CX₃CR₁^gfp/+ transgenic mouse identified two distinct CX₃CR₁⁺ mononuclear phagocyte (macrophage and dendritic cell) populations: stellate/dendriform cells opposed to the seminiferous tubules (peritubular), and polygonal cells associated with Leydig cells (interstitial). Using confocal microscopy combined with stereological enumeration of CX₃CR₁^gfp/+ cells established that there were twice as many interstitial cells (68%) as peritubular cells (32%). Flow cytometric analyses of interstitial cells from mechanically-dissociated testes identified multiple mononuclear phagocyte subsets based on surface marker expression (CX₃CR₁, F4/80, CD11c). These cells comprised 80% of total intratesticular leukocytes, as identified by CD45 expression. The remaining leukocytes were CD3⁺ (T lymphocytes) and NK1.1⁺ (natural killer cells). Functional phenotype assessment using CD206 (an anti-inflammatory/M2 marker) and MHC class II (an activation marker) identified a potentially tolerogenic CD206⁺MHCII⁺ sub-population (12% of total CD45⁺ cells). Rare testicular subsets of CX₃CR₁⁺CD11c⁺F4/80⁺ (4.3%) mononuclear phagocytes and CD3⁺NK1.1⁺ (3.1%) lymphocytes were also identified for the first time. In order to examine the potential for the immunoregulatory cytokine, activin A to modulate testicular immune cell populations, testes from adult mice with reduced activin A (Inhba^+/-) or elevated activin A (Inha^+/-) were assessed using flow cytometry. Although the proportion of F4/80⁺CD11b⁺ leukocytes (macrophages) was not affected, the frequency of CD206⁺MHCII⁺cells was significantly lower and CD206⁺MHCII^- correspondingly higher in Inha^+/- testes. This shift in expression of MHCII in CD206⁺ macrophages indicates that changes in circulating and/or local activin A influence resident macrophage activation and phenotype and, therefore, the immunological environment of the testis.

Serum IL-1RA levels increase from follicular to luteal phase of the ovarian cycle: A pilot study on human female immune responses

The immune responses exhibited by females are distinct from those of males. Females are known to generate, among others, higher levels of antibodies, greater interferon responses, and increased levels of inflammatory mediators in response to pathogens. Mounting evidence suggests that gonadal hormones play a key role in these differences. To better understand the effect of cycling hormones on the immune response, we sought to investigate the relationship between gonadal hormone fluctuations during the ovarian cycle and the levels of interleukin 1β and IL-1RA, both in circulation and in PBMCs in response to TLR4 stimulation, in healthy premenopausal females. To do this we measured the gonadal hormones 17β-estradiol, progesterone, and luteinizing hormone, and the cytokines IL-1β and IL-1RA in nine cycling females at several time points throughout one complete cycle. We evaluated 35 follicular, 17 ovulatory, and 44 luteal time points in our cohort and found a clear increase in serum levels of anti-inflammatory IL-1RA in the luteal phase, as compared to the follicular phase, and a positive correlation between both 17β-estradiol and progesterone and IL-RA. There was no difference in the serum levels of IL-1β and no difference in IL-1 β or IL-1RA produced in response to LPS by PBMCs isolated from different phases. Division of the cycle into sub-phases revealed an increase in the level of IL-1RA by ovulation that persisted through the luteal phase. These data suggest that significant changes in the immune response occur throughout the ovarian cycle in healthy females.

Toll-Like Receptors Contribute to Sex Differences in Blood Pressure Regulation

Toll-like receptors (TLRs) play an important role in the innate immune system, and recently, they have been shown to be involved in the regulation of blood pressure. The incidence of hypertension is higher in men, and it increases in postmenopausal women. In fact, premenopausal women are protected from cardiovascular disease compared with age-matched men, and it is well established that this protective effect is lost with menopause. However, the molecular mechanisms underlying this protection in women are unknown. Whether or not it could be related to differential activation of the innate immune system remains to be elucidated. This review focuses on (1) the differences between men and women in TLR activation and (2) whether TLR activation may influence the regulation of blood pressure in a sex-dependent manner.

Immune and sex-biased gene expression in the threatened Mojave desert tortoise, Gopherus agassizii

The immune system of ectotherms, particularly non-avian reptiles, remains poorly characterized regarding the genes involved in immune function, and their function in wild populations. We used RNA-Seq to explore the systemic response of Mojave desert tortoise (Gopherus agassizii) gene expression to three levels of Mycoplasma infection to better understand the host response to this bacterial pathogen. We found over an order of magnitude more genes differentially expressed between male and female tortoises (1,037 genes) than differentially expressed among immune groups (40 genes). There were 8 genes differentially expressed among both variables that can be considered sex-biased immune genes in this tortoise. Among experimental immune groups we find enriched GO biological processes for cysteine catabolism, regulation of type 1 interferon production, and regulation of cytokine production involved in immune response. Sex-biased transcription involves iron ion transport, iron ion homeostasis, and regulation of interferon-beta production to be enriched. More detailed work is needed to assess the seasonal response of the candidate genes found here. How seasonal fluctuation of testosterone and corticosterone modulate the immunosuppression of males and their susceptibility to Mycoplasma infection also warrants further investigation, as well as the importance of iron in the immune function and sex-biased differences of this species. Finally, future transcriptional studies should avoid drawing blood from tortoises via subcarapacial venipuncture as the variable aspiration of lymphatic fluid will confound the differential expression of genes.

Proteoglycans in the Pathogenesis of Hormone-Dependent Cancers: Mediators and Effectors

Hormone-dependent cancers exhibit high morbidity and mortality. In spite of advances in therapy, the treatment of hormone-dependent cancers remains an unmet health need. The tumor microenvironment (TME) exhibits unique characteristics that differ among various tumor types. It is composed of cancerous, non-cancerous, stromal, and immune cells that are surrounded and supported by components of the extracellular matrix (ECM). Therefore, the interactions among cancer cells, stromal cells, and components of the ECM determine cancer progression and response to therapy. Proteoglycans (PGs), hybrid molecules consisting of a protein core to which sulfated glycosaminoglycan chains are bound, are significant components of the ECM that are implicated in all phases of tumorigenesis. These molecules, secreted by both the stroma and cancer cells, are crucial signaling mediators that modulate the vital cellular pathways implicated in gene expression, phenotypic versatility, and response to therapy in specific tumor types. A plethora of deregulated signaling pathways contributes to the growth, dissemination, and angiogenesis of hormone-dependent cancers. Specific inputs from the endocrine and immune systems are some of the characteristics of hormone-dependent cancer pathogenesis. Importantly, the mechanisms involved in various aspects of cancer progression are executed in the ECM niche of the TME, and the PG components crucially mediate these processes. Here, we comprehensively discuss the mechanisms through which PGs affect the multifaceted aspects of hormone-dependent cancer development and progression, including cancer metastasis, angiogenesis, immunobiology, autophagy, and response to therapy.

Possible protective role of 17β-estradiol against COVID-19

Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is the virus that causes coronavirus disease 2019 (COVID-19); a worldwide pandemic as declared by the World Health Organization (WHO). SARS-CoV-2 appears to infect cells by first binding and priming its viral-spike proteins with membrane-associated angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2). Through the coordinated actions of ACE2 and TMPRSS2, SARS-CoV-2 spike proteins fuse with plasma membranes and ultimately the virus enters cells. ACE2 is integral to the renin-angiotensin-aldosterone system (RAAS), and SARS-CoV-2 down-regulates protein expression levels of ACE2. Once infected, patients typically develop acute respiratory distress syndrome (ARDS) and a number of other severe complications that result in a high rate of fatality, especially in older (>60 years) adults and in people with pre-existing medical conditions. Data now indicate clearly that among people of all age groups, COVID-19 fatalities are higher in men than women. Here, attention is focused on these sex differences and posit a role of estrogen in these differences as well as possible therapeutic and protective actions of 17β-estradiol against COVID-19.

Androgen and Androgen Receptors as Regulators of Monocyte and Macrophage Biology in the Healthy and Diseased Lung

Androgens, the predominant male sex hormones, drive the development and maintenance of male characteristics by binding to androgen receptor (AR). As androgens are systemically distributed throughout the whole organism, they affect many tissues and cell types in addition to those in male sexual organs. It is now clear that the immune system is a target of androgen action. In the lungs, many immune cells express ARs and are responsive to androgens. In this review, we describe the effects of androgens and ARs on lung myeloid immune cells-monocytes and macrophages-as they relate to health and disease. In particular, we highlight the effect of androgens on lung diseases, such as asthma, chronic obstructive pulmonary disease and lung fibrosis. We also discuss the therapeutic use of androgens and how circulating androgens correlate with lung disease. In addition to human studies, we also discuss how mouse models have helped to uncover the effect of androgens on monocytes and macrophages in lung disease. Although the role of estrogen and other female hormones has been broadly analyzed in the literature, we focus on the new perspectives of androgens as modulators of the immune system that target myeloid cells during lung inflammation.

Considerations for Studying Sex as a Biological Variable in Spinal Cord Injury

In response to NIH initiatives to investigate sex as a biological variable in preclinical animal studies, researchers have increased their focus on male and female differences in neurotrauma. Inclusion of both sexes when modeling neurotrauma is leading to the identification of novel areas for therapeutic and scientific exploitation. Here, we review the organizational and activational effects of sex hormones on recovery from injury and how these changes impact the long-term health of spinal cord injury (SCI) patients. When determining how sex affects SCI it remains imperative to expand outcomes beyond locomotor recovery and consider other complications plaguing the quality of life of patients with SCI. Interestingly, the SCI field predominately utilizes female rodents for basic science research which contrasts most other male-biased research fields. We discuss the unique caveats this creates to the translatability of preclinical research in the SCI field. We also review current clinical and preclinical data examining sex as biological variable in SCI. Further, we report how technical considerations such as housing, size, care management, and age, confound the interpretation of sex-specific effects in animal studies of SCI. We have uncovered novel findings regarding how age differentially affects mortality and injury-induced anemia in males and females after SCI, and further identified estrus cycle dysfunction in mice after injury. Emerging concepts underlying sexually dimorphic responses to therapy are also discussed. Through a combination of literature review and primary research observations we present a practical guide for considering and incorporating sex as biological variable in preclinical neurotrauma studies.

Individual and joint association of bioavailable testosterone and aging with neutrophil-to-lymphocyte ratio in Chinese middle-aged and elderly men

BACKGROUND AND OBJECTIVES

Accumulating evidences suggest that chronic systemic inflammation (CSI) is independently associated with large number of major non-communicable chronic diseases (NCDs) ranging from metabolic disorders to cancers, and neutrophil-to-lymphocyte ratio (NLR) has been accepted as a novel, convenient marker for CSI response. Testosterone deficiency in men is linked to high risk of NCDs. This cross-sectional study aimed to investigate the individual and joint association of bioavailable testosterone (BIOT) and aging with NLR.

METHODS

A total of 132 male adults were enrolled during Jan. 2011 and Oct. 2017 in the first affiliated hospital of University of Science and Technology of China. Local weighted regression (LOESS) and multivariable generalized linear regression models were utilized to comprehensively examine the individual and joint association between BIOT and age with NLR.

RESULTS

Obvious linear relationships between NLR and BIOT or age were observed with the LOESS models. NLR was negatively correlated to BIOT after adjusting for some potential confounding factors (P = 0.034). As compared to the lowest quartile of BIOT, the adjusted decrease of NLR for the 2nd, 3rd and 4th quartiles were 0.40, 0.64 and 0.72, respectively. Meanwhile, NLR was observed to be independently correlated to elevated age (P = 0.043). Furthermore, as compared to the counterparts, men over 70 years combined with plasma BIOT less than 4.7 nmol/L had the highest NLR level, which suggested that low BIOT and aging jointly correlated to the level of NLR (P = 0.005).

CONCLUSION

BIOT deficiency and aging were individually and jointly correlated to CSI. Men over 70 years combined with BIOT < 4.7 nmol/L were more like to have higher grade of CSI than others.

Sexual dimorphism of physical activity on cognitive aging: Role of immune functioning

OBJECTIVE

Exercise is one of the most potent strategies available to support cognitive health with age, yet substantial variability exists. Sexual dimorphism is evident for brain and immune functioning, the latter being implicated as important pathway for exercise. We examined the moderating role of sex on the relationship between physical activity and systemic inflammatory and brain health outcomes in support of more personalized approaches to behavioral interventions.

METHODS

Our discovery cohort included 45 typically aging women matched on age (±5y) and education (±2y) to 45 men (mean age = 72.5; Clinical Dementia Rating = 0) who completed self-reported current physical activity (Physical Activity Scale for Elderly), blood draw, neuropsychological evaluation, and brain MRI. An independent sample of 45 typically aging women and 36 men who completed the same measures comprised a replication cohort. Plasma was analyzed for 11 proinflammatory cytokine and chemokine markers via MesoScale Discovery.

RESULTS

Discovery cohort: Reported physical activity did not differ between sexes (150 vs. 157, p = 0.72). There was a significant interaction between sex and physical activity on chemokine markers MDC, MIP-1b, MCP-4, and eotaxin-3 (ps < 0.03), with a similar trend for MCP-1 and INFγ (ps < 0.09). Men who reported greater activity demonstrated lower inflammatory markers, an effect attenuated-to-absent in women. An interaction between sex and physical activity was also observed for parahippocampal volumes (p = 0.02) and cognition (processing speed and visual memory; ps < 0.04). Again, the beneficial effect of physical activity on outcomes was present in men, but not women. Replication cohort analyses conferred a consistent effect of sex on the relationship between physical activity and immune markers; models examining neurobehavioral outcomes did not strongly replicate. Across cohorts, post-hoc models demonstrated an interaction between sex and activity-related inflammatory markers on total gray matter volume and visual memory. Men with higher inflammatory markers demonstrated poorer brain structure and function, whereas inflammatory markers did not strongly relate to neurobehavioral outcomes in women.

CONCLUSIONS

Greater physical activity was associated with lower markers of inflammation in clinically normal older men, but not women - an effect consistently replicated across cohorts. Additionally, men appeared disproportionately vulnerable to the adverse effects of peripheral inflammatory markers on brain structure and function compared to women. Immune activation may be a male-specific pathway through which exercise confers neurobehavioral benefit.

Androgen-Influenced Polarization of Activin A-Producing Macrophages Accompanies Post-pyelonephritic Renal Scarring

Ascending bacterial pyelonephritis, a form of urinary tract infection (UTI) that can result in hospitalization, sepsis, and other complications, occurs in ~250,000 US patients annually; uropathogenic Escherichia coli (UPEC) cause a large majority of these infections. Although UTIs are primarily a disease of women, acute pyelonephritis in males is associated with increased mortality and morbidity, including renal scarring, and end-stage renal disease. Preclinical models of UTI have only recently allowed investigation of sex and sex-hormone effects on pathogenesis. We previously demonstrated that renal scarring after experimental UPEC pyelonephritis is augmented by androgen exposure; testosterone exposure increases both the severity of pyelonephritis and the degree of renal scarring in both male and female mice. Activin A is an important driver of scarring in non-infectious renal injury, as well as a mediator of macrophage polarization. In this work, we investigated how androgen exposure influences immune cell recruitment to the UPEC-infected kidney and how cell-specific activin A production affects post-pyelonephritic scar formation. Compared with vehicle-treated females, androgenized mice exhibited reduced bacterial clearance from the kidney, despite robust myeloid cell recruitment that continued to increase as infection progressed. Infected kidneys from androgenized mice harbored more alternatively activated (M2) macrophages than vehicle-treated mice, reflecting an earlier shift from a pro-inflammatory (M1) phenotype. Androgen exposure also led to a sharp increase in activin A-producing myeloid cells in the infected kidney, as well as decreased levels of follistatin (which normally antagonizes activin action). As a result, infection in androgenized mice featured prolonged polarization of macrophages toward a pro-fibrotic M2a phenotype, accompanied by an increase in M2a-associated cytokines. These data indicate that androgen enhancement of UTI severity and resulting scar formation is related to augmented local activin A production and corresponding promotion of M2a macrophage polarization.

COVID-19 Clinical Characteristics, and Sex-Specific Risk of Mortality: Systematic Review and Meta-Analysis

Background: The rapidly evolving coronavirus disease 2019 (COVID-19), was declared a pandemic by the World Health Organization on March 11, 2020. It was first detected in the Wuhan city of China and has spread globally resulting in a substantial health and economic crisis in many countries. Observational studies have partially identified different aspects of this disease. There have been no published systematic reviews that combine clinical, laboratory, epidemiologic, and mortality findings. Also, the effect of gender on the outcomes of COVID-19 has not been well-defined.

Methods: We reviewed the scientific literature published from January 1, 2019 to May 29, 2020. Statistical analyses were performed with STATA (version 14, IC; Stata Corporation, College Station, TX, USA). The pooled frequency with 95% confidence intervals (CI) was assessed using random effect model. P < 0.05 was considered a statistically significant publication bias.

Results: Out of 1,223 studies, 34 satisfied the inclusion criteria. A total of 5,057 patients with a mean age of 49 years were evaluated. Fever (83.0%, CI 77.5–87.6) and cough (65.2%, CI 58.6–71.2) were the most common symptoms. The most prevalent comorbidities were hypertension (18.5%, CI 12.7–24.4) and Cardiovascular disease (14.9%, CI 6.0–23.8). Among the laboratory abnormalities, elevated C-Reactive Protein (CRP) (72.0%, CI 54.3–84.6) and lymphopenia (50.1%, CI 38.0–62.4) were the most common. Bilateral ground-glass opacities (66.0%, CI 51.1–78.0) was the most common CT scan presentation. The pooled mortality rate was 6.6%, with males having significantly higher mortality compared to females (OR 3.4; 95% CI 1.2–9.1, P = 0.01).

Conclusion: COVID-19 has caused a significant number of hospitalization and mortality worldwide. Mortality associated with COVID-19 was higher in our study compared to the previous reports from China. The mortality was significantly higher among the hospitalized male group. Further studies are required to evaluate the effect of different variables resulting in sex disparity in COVID-19 mortality.

Influence of Androgens on Immunity to Self and Foreign: Effects on Immunity and Cancer

It is well-known that sex hormones can directly and indirectly influence immune cell function. Different studies support a suppressive role of androgens on different components of the immune system by decreasing antibody production, T cell proliferation, NK cytotoxicity, and stimulating the production of anti-inflammatory cytokines. Androgen receptors have also been detected in many different cells of hematopoietic origin leading to direct effects of their ligands on the development and function of the immune system. The immunosuppressive properties of androgens could contribute to gender dimorphisms in autoimmune and infectious disease and thereby also hamper immune surveillance of tumors. Consistently, females generally are more prone to autoimmunity, while relatively less susceptible to infections, and have lower incidence and mortality of the majority of cancers compared to males. Some studies show that androgen deprivation therapy (ADT) can induce expansion of naïve T cells and increase T-cell responses. Emerging clinical data also reveal that ADT might enhance the efficacy of various immunotherapies including immune checkpoint blockade. In this review, we will discuss the potential role of androgens and their receptors in the immune responses in the context of different diseases. A particular focus will be on cancer, highlighting the effect of androgens on immune surveillance, tumor biology and on the efficacy of anti-cancer therapies including emerging immune therapies.

Understanding COVID-19: Digit ratio (2D:4D) and sex differences in national case fatality rates

BACKGROUND

The reported national case fatality rates (CFRs) for coronavirus disease 2019 (COVID-19) shows a sex bias with males > females. The relative lengths of the index (2D) and ring (4D) fingers (digit ratio; 2D:4D) is a sexually dimorphic (males < females) proxy of fetal sex steroids (low 2D:4D indicates high prenatal testosterone/low prenatal estrogen).

AIM

To examine sex-specific relationships of 2D:4D per nation with national values of COVID-19 CFRs.

STUDY DESIGN

COVID-19 CFRs and the percent of male deaths were related to mean national (self-reported) 2D:4D by sex and hand from a large online survey (the BBC Internet Study).

SUBJECTS

103,482 men and 83,366 women.

OUTCOME MEASURES

Relationships of mean national 2D:4D with CFRs from 41 countries and with national male death rates from 16 countries.

RESULTS

Male right and left hand 2D:4D showed positive relationships with CFR. These relationships remained significant after removing the influence of female 2D:4D. A positive association of male right and left 2D:4D was detected with the percentage of male deaths.

CONCLUSIONS

At the national level, high mean 2D:4D (indicating low prenatal testosterone/high prenatal estrogen) is associated with high CFRs and percent male mortality. At the individual level, high 2D:4D may be a risk factor for severity of COVID-19 in males. We speculate that male 2D:4D is a negative correlate for expression of the SARS-CoV2 receptor (ACE2).

Essential roles of interstitial cells in testicular development and function

BACKGROUND

Testicular architecture and sperm production are supported by a complex network of communication between various cell types. These signals ensure fertility by: regulating spermatogonial stem/progenitor cells; promoting steroidogenesis; and driving male-specific differentiation of the gonad. Sertoli cells have long been assumed to be the major cellular player in testis organogenesis and spermatogenesis. However, cells in the interstitial compartment, such as Leydig, vascular, immune, and peritubular cells, also play prominent roles in the testis but are less well understood.

OBJECTIVES

Here, we aim to outline our current knowledge of the cellular and molecular mechanisms by which interstitial cell types contribute to spermatogenesis and testicular development, and how these diverse constituents of the testis play essential roles in ensuring male sexual differentiation and fertility.

METHODS

We surveyed scientific literature and summarized findings in the field that address how interstitial cells interact with other interstitial cell populations and seminiferous tubules (i.e., Sertoli and germ cells) to support spermatogenesis, male-specific differentiation, and testicular function. These studies focused on 4 major cell types: Leydig cells, vascular cells, immune cells, and peritubular cells.

RESULTS AND DISCUSSION

A growing number of studies have demonstrated that interstitial cells play a wide range of functions in the fetal and adult testis. Leydig cells, through secretion of hormones and growth factors, are responsible for steroidogenesis and progression of spermatogenesis. Vascular, immune, and peritubular cells, apart from their traditionally acknowledged physiological roles, have a broader importance than previously appreciated and are emerging as essential players in stem/progenitor cell biology.

CONCLUSION

Interstitial cells take part in complex signaling interactions with both interstitial and tubular cell populations, which are required for several biological processes, such as steroidogenesis, Sertoli cell function, spermatogenesis, and immune regulation. These various processes are essential for testicular function and demonstrate how interstitial cells are indispensable for male fertility.

Impact of Androgens on Inflammation-Related Lipid Mediator Biosynthesis in Innate Immune Cells

Rheumatoid arthritis, asthma, allergic rhinitis and many other disorders related to an aberrant immune response have a higher incidence and severity in women than in men. Emerging evidences from scientific studies indicate that the activity of the immune system is superior in females and that androgens may act as “immunosuppressive” molecules with inhibitory effects on inflammatory reactions. Among the multiple factors that contribute to the inflammatory response, lipid mediators (LM), produced from polyunsaturated fatty acids, represent a class of bioactive small molecules with pivotal roles in the onset, maintenance and resolution of inflammation. LM encompass pro-inflammatory eicosanoids and specialized pro-resolving mediators (SPM) that coexist in a tightly regulated balance necessary for the return to homeostasis. Innate immune cells including neutrophils, monocytes and macrophages possess high capacities to generate distinct LM. In the last decades it became more and more evident that sex represents an important variable in the regulation of inflammation where sex hormones play crucial roles. Recent findings showed that the biosynthesis of inflammation-related LM is sex-biased and that androgens impact LM formation with consequences not only for pathophysiology but also for pharmacotherapy. Here, we review the modulation of the inflammatory response by sex and androgens with a specific focus on LM pathways. In particular, we highlight the impact of androgens on the biosynthetic pathway of inflammation-related eicosanoids in innate immune cells.

Cannabinoid Receptor Type 2: A Possible Target in SARS-CoV-2 (CoV-19) Infection?

In late December 2019, a novel coronavirus (SARS-CoV-2 or CoV-19) appeared in Wuhan, China, causing a global pandemic. SARS-CoV-2 causes mild to severe respiratory tract inflammation, often developing into lung fibrosis with thrombosis in pulmonary small vessels and causing even death. COronaVIrus Disease (COVID-19) patients manifest exacerbated inflammatory and immune responses, cytokine storm, prevalence of pro-inflammatory M1 macrophages and increased levels of resident and circulating immune cells. Men show higher susceptibility to SARS-CoV-2 infection than women, likely due to estrogens production. The protective role of estrogens, as well as an immune-suppressive activity that limits the excessive inflammation, can be mediated by cannabinoid receptor type 2 (CB2). The role of this receptor in modulating inflammation and immune response is well documented in fact in several settings. The stimulation of CB2 receptors is known to limit the release of pro-inflammatory cytokines, shift the macrophage phenotype towards the anti-inflammatory M2 type and enhance the immune-modulating properties of mesenchymal stromal cells. For these reasons, we hypothesize that CB2 receptor can be a therapeutic target in COVID-19 pandemic emergency.

COVID-19 and Individual Genetic Susceptibility/Receptivity: Role of ACE1/ACE2 Genes, Immunity, Inflammation and Coagulation. Might the Double X-chromosome in Females Be Protective against SARS-CoV-2 Compared to the Single X-Chromosome in Males?

In December 2019, a novel severe acute respiratory syndrome (SARS) from a new coronavirus (SARS-CoV-2) was recognized in the city of Wuhan, China. Rapidly, it became an epidemic in China and has now spread throughout the world reaching pandemic proportions. High mortality rates characterize SARS-CoV-2 disease (COVID-19), which mainly affects the elderly, causing unrestrained cytokines-storm and subsequent pulmonary shutdown, also suspected micro thromboembolism events. At the present time, no specific and dedicated treatments, nor approved vaccines, are available, though very promising data come from the use of anti-inflammatory, anti-malaria, and anti-coagulant drugs. In addition, it seems that males are more susceptible to SARS-CoV-2 than females, with males 65% more likely to die from the infection than females. Data from the World Health Organization (WHO) and Chinese scientists show that of all cases about 1.7% of women who contract the virus will die compared with 2.8% of men, and data from Hong Kong hospitals state that 32% of male and 15% of female COVID-19 patients required intensive care or died. On the other hand, the long-term fallout of coronavirus may be worse for women than for men due to social and psychosocial reasons. Regardless of sex- or gender-biased data obtained from WHO and those gathered from sometimes controversial scientific journals, some central points should be considered. Firstly, SARS-CoV-2 has a strong interaction with the human ACE2 receptor, which plays an essential role in cell entry together with transmembrane serine protease 2 (TMPRSS2); it is interesting to note that the ACE2 gene lays on the X-chromosome, thus allowing females to be potentially heterozygous and differently assorted compared to men who are definitely hemizygous. Secondly, the higher ACE2 expression rate in females, though controversial, might ascribe them the worst prognosis, in contrast with worldwide epidemiological data. Finally, several genes involved in inflammation are located on the X-chromosome, which also contains high number of immune-related genes responsible for innate and adaptive immune responses to infection. Other genes, out from the RAS-pathway, might directly or indirectly impact on the ACE1/ACE2 balance by influencing its main actors (e.g., ABO locus, SRY, SOX3, ADAM17). Unexpectedly, the higher levels of ACE2 or ACE1/ACE2 rebalancing might improve the outcome of COVID-19 in both sexes by reducing inflammation, thrombosis, and death. Moreover, X-heterozygous females might also activate a mosaic advantage and show more pronounced sex-related differences resulting in a sex dimorphism, further favoring them in counteracting the progression of the SARS-CoV-2 infection.

The impact of sex and gender on immunotherapy outcomes

Immunotherapies are often used for the treatment, remission, and possible cure of autoimmune diseases, infectious diseases, and cancers. Empirical evidence illustrates that females and males differ in outcomes following the use of biologics for the treatment of autoimmune diseases, e.g., rheumatoid arthritis (RA), infectious diseases, e.g., influenza, and solid tumor cancers. Females tend to experience more adverse reactions than males following the use of a class of biologics referred to as immunotherapies. For immunotherapies aimed at stimulating an immune response, e.g., influenza vaccines, females develop greater responses and may experience greater efficacy than males. In contrast, for immunotherapies that repress an immune response, e.g., tumor necrosis factor (TNF) inhibitors for RA or checkpoint inhibitors for melanoma, the efficacy is reportedly greater for males than females. Despite these differences, discrepancies in reporting differences between females and males exist, with females have been historically excluded from biomedical and clinical studies. There is a critical need for research that addresses the biological (i.e., sex) as well as sociocultural (i.e., gender) causes of male-female disparities in immunotherapy responses, toxicities, and outcomes. One-size-fits-all approaches to immunotherapies will not work, and sex/gender may contribute to variable treatment success, including adherence, in clinical settings.

Neuroprotection by dihydrotestosterone in LPS-induced neuroinflammation

Microglia-induced neuroinflammation plays a vital role in the etiology and progression of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease and multiple sclerosis. The neuroprotective role of androgens, including testosterone and its metabolite dihydrotestosterone (DHT), has been increasingly demonstrated in these diseases, but few studies investigated the effects of androgen on neuroinflammation. This study investigated the role of DHT in lipopolysaccharide (LPS)-induced neuroinflammation, neuronal damage and behavioral dysfunction, as well as underlying mechanisms. We showed that DHT inhibited LPS-induced release of proinflammatory factors, including TNF-α, IL-1β, IL-6; iNOS, COX-2, NO, and PGE2 in BV2 cells and primary microglia by suppressing the TLR4-mediated NF-κB and MAPK p38 signaling pathways, thus protecting SH-SY5Y neurons from inflammatory damage induced by activated microglia. In an LPS-induced neuroinflammation mouse model, endogenous DHT depletion by castration exacerbated inflammatory responses by upregulating the levels of TNF-α, IL-1β, IL-6, iNOS, and COX-2 in the serum and brain by increasing the LR4-mediated NF-κB and MAPK pathway activation, but these effects were restored by exogenous DHT supplementation. Moreover, DHT also regulated the mRNA levels of the anti-inflammatory cytokines IL-10 and IL-13 in the brain. In addition, DHT modulated the expression of Aβ, the apoptotic proteins caspase-3, Bcl-2, and Bax, and synaptophysin, as well as neuronal damage in LPS-treated mouse brains. Further behavioral tests revealed that DHT ameliorated LPS-induced spatial and learning impairment and motor incoordination, and partly improved the locomotor activity in LPS-injected mice. Therefore, this study suggests that DHT exerts anti-neuroinflammatory and neuroprotective effects; thus, androgen replacement therapy is a potential therapeutic strategy for improving cognitive and behavioral function in neuroinflammation-related diseases.

TLR2 and TLR4 Surface and Gene Expression in White Blood Cells after Fasting and Oral Glucose, Lipid and Protein Challenges: Influence of Obesity and Sex Hormones

We studied if macronutrients of the diet have different effects on leukocyte activation, and if these effects are influenced by sex hormones or obesity. We analyzed leukocyte cell surface and gene expression of toll-like receptors 2 and 4 (TLR2 and TLR4) during fasting and after macronutrient loads in women with polycystic ovary syndrome and female and male controls. Fasting TLR2 surface expression in neutrophils was higher in men than in women. Obese subjects presented higher TLR2 gene expression than nonobese individuals, particularly in men. In contrast, surface TLR4 expression was lower in men and in obese individuals. Postprandial cell-surface expression decreased similarly after all macronutrient loads. Neutrophil TLR2 decreased only in obese subjects whereas TLR4 showed a greater decrease in nonobese individuals. However, TLR2 gene expression increased after glucose ingestion and decreased during the lipid load, while TLR4 was induced in response to lipids and mostly to glucose. Postprandial TLR gene expression was not influenced by group of subjects or obesity. Both cell-surface and gene postprandial expression inversely correlated with their fasting levels. These responses suggest a transient compensatory response aiming to prevent postprandial inflammation. However, obesity and sex hormones showed opposite influences on surface expression of TLR2 and TLR4, but not on their gene expression, pointing to regulatory posttranscriptional mechanisms.

Sexual Dimorphism in Innate Immunity

Sexual dimorphisms account for differences in clinical manifestations or incidence of infectious or autoimmune diseases and malignancy between females and males. Females develop enhanced innate and adaptive immune responses than males and are less susceptible to many infections of bacterial, viral, parasitic, and fungal origin and malignancies but in contrast, they are more prone to develop autoimmune diseases. The higher susceptibility to infections in males is observed from birth to adulthood, suggesting that sex chromosomes and not sex hormones have a major role in sexual dimorphism in innate immunity. Sex-based regulation of immune responses ultimately contributes to age-related disease development and life expectancy. Differences between males and females have been described in the expression of pattern recognition receptors of the innate immune response and in the functional responses of phagocytes and antigen presenting cells. Different factors have been shown to account for the sex-based disparity in immune responses, including genetic factors and hormonal mediators, which contribute independently to dimorphism in the innate immune response. For instance, several genes encoding for innate immune molecules are located on the X chromosome. In addition, estrogen and/or testosterone have been reported to modulate the differentiation, maturation, lifespan, and effector functions of innate immune cells, including neutrophils, macrophages, natural killer cells, and dendritic cells. In this review, we will focus on differences between males and females in innate immunity, which represents the first line of defense against pathogens and plays a fundamental role in the activation, regulation, and orientation of the adaptive immune response.

Role of environmental factors in the pathogenesis of Crohn's disease: a critical review

PURPOSE

To review role of environmental factors in the pathogenesis of Crohn's disease.

METHODS

We systematically reviewed trials and systematic reviews using PubMed and Web of science databases. Here, we review the current information on the causative factors and mechanisms of CD, including smoking, exercise, diet, animal protein, breastfeeding, history of childhood infection and vaccination, oral contraceptives, and antibiotics of CD. We also highlight important knowledge gaps that need to be filled in order to advance the field of CD research.

RESULTS

Epidemiological studies have indicated the significance of environmental factors in the disease behavior and outcome of Crohn's disease (CD). There are a few recognized environmental factors, such as cigarette smoking, exercise, dietary habits, and breastfeeding, which are associated with the pathogenesis of CD. These factors are hypothesized to change the epithelial barrier function, which disturbs both the innate and adaptive immune systems and the intestinal flora. However, the effect of several risk factors, such as appendectomy and pharmaceutical use, differs across several studies, indicating the need for more rigorous research. Furthermore, few studies have examined effective interventions based on environmental factors that can improve disease outcomes. Recent studies have indicated that the pathogenesis of CD is related to environmental and genetic factors.

CONCLUSION

We review the current information on the causative factors and mechanisms of CD, including smoking, exercise, diet, animal protein, breastfeeding, history of childhood infection and vaccination, oral contraceptives, and antibiotics of CD. However, further studies are needed to understand knowledge gaps in the field of CD.

The Effect of Androgens on Proinflammatory Cytokine Secretion from Human Ocular Surface Epithelial Cells

Purpose: The purpose of this study is to explore the effects of dihydrotestosterone (DHT) on lipopolysaccharide (LPS)-induced proinflammatory cytokine release in human ocular surface epithelial cells exposed to LPS and LPS-binding protein (LBP).Methods: Immortalized human corneal, conjunctival, and meibomian gland epithelial cells were cultured in keratinocyte-free medium. After confluency, they were exposed to a stratification medium Dulbecco's modified Eagle medium (DMEM)/F12 in the presence of fetal bovine serum and were exposed to vehicle, LPS + LBP, or DHT. Culture media were processed for multiplex-bead analysis of specific proinflammatory cytokines including interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-2, IL-4, IL-8, IL-6, IL-10, IL-1β, vascular endothelial growth factor (VEGF)-A. Cytokine concentrations were compared by analysis of variance with Tukey post hoc testing. p < 0.05 was considered statistically significant.Results: The results are LPS + LBP-induced the secretion of IFN-γ, IL-6, IL-10, IL-1β, VEGF-A cytokines in corneal epithelial cells; TNF-α, IL-2, IL-8, IL-6, IL-1β, VEGF-A cytokines in conjunctival epithelial cells; and IL-8, IL-6, IL-1β, VEGF-A cytokines in meibomian gland epithelial cells. When these LPS + LBP-stimulated cells were exposed to DHT for 2 days, it was found that DHT suppressed the secretion of IL-6, IL-10, IL-1β, VEGF-A cytokines in corneal epithelial cells; TNF-α, IL-6, IL-1β, VEGF-A cytokines in conjunctival epithelial cells; and IL-6, IL-1β, VEGF-A cytokines in meibomian gland epithelial cells.Conclusion: LPS + LBP is shown to induce the secretion of certain proinflammatory cytokines from ocular surface and adnexal epithelial cells. DHT showed anti-inflammatory activity by suppressing some of those cytokines in these cell lines.

Dynamic response of microglia/macrophage polarization following demyelination in mice

BACKGROUND

The glial response in multiple sclerosis (MS), especially for recruitment and differentiation of oligodendrocyte progenitor cells (OPCs), predicts the success of remyelination of MS plaques and return of function. As a central player in neuroinflammation, activation and polarization of microglia/macrophages (M/M) that modulate the inflammatory niche and cytokine components in demyelination lesions may impact the OPC response and progression of demyelination and remyelination. However, the dynamic behaviors of M/M and OPCs during demyelination and spontaneous remyelination are poorly understood, and the complex role of neuroinflammation in the demyelination-remyelination process is not well known. In this study, we utilized two focal demyelination models with different dynamic patterns of M/M to investigate the correlation between M/M polarization and the demyelination-remyelination process.

METHODS

The temporal and spatial features of M/M activation/polarization and OPC response in two focal demyelination models induced by lysolecithin (LPC) and lipopolysaccharide (LPS) were examined in mice. Detailed discrimination of morphology, sensorimotor function, diffusion tensor imaging (DTI), inflammation-relevant cytokines, and glial responses between these two models were analyzed at different phases.

RESULTS

The results show that LPC and LPS induced distinctive temporal and spatial lesion patterns. LPS produced diffuse demyelination lesions, with a delayed peak of demyelination and functional decline compared to LPC. Oligodendrocytes, astrocytes, and M/M were scattered throughout the LPS-induced demyelination lesions but were distributed in a layer-like pattern throughout the LPC-induced lesion. The specific M/M polarization was tightly correlated to the lesion pattern associated with balance beam function.

CONCLUSIONS

This study elaborated on the spatial and temporal features of neuroinflammation mediators and glial response during the demyelination-remyelination processes in two focal demyelination models. Specific M/M polarization is highly correlated to the demyelination-remyelination process probably via modulations of the inflammatory niche, cytokine components, and OPC response. These findings not only provide a basis for understanding the complex and dynamic glial phenotypes and behaviors but also reveal potential targets to promote/inhibit certain M/M phenotypes at the appropriate time for efficient remyelination.

Sex-differences in LPS-induced neonatal lung injury

Being of the male sex has been identified as a risk factor for multiple morbidities associated with preterm birth, including bronchopulmonary dysplasia (BPD). Exposure to inflammatory stress is a well-recognized risk factor for developing BPD. Whether there is a sex difference in pulmonary innate immune TLR4 signaling, lung injury and subsequent abnormal lung development is unknown. Neonatal (P0) male and female mice (ICR) were exposed to systemic LPS (5 mg/kg, IP) and innate immune signaling, and the transcriptional response were assessed (1 and 5 hours), along with lung development (P7). Male and female mice demonstrated a similar degree of impaired lung development with decreased radial alveolar counts, increased surface area, increased airspace area and increased mean linear intercept. We found no differences between male and female mice in the baseline pulmonary expression of key components of TLR4-NFκB signaling, or in the LPS-induced pulmonary expression of key mediators of neonatal lung injury. Finally, we found no difference in the kinetics of LPS-induced pulmonary NFκB activation between male and female mice. Together, these data support the conclusion that the innate immune response to early postnatal LPS exposure and resulting pulmonary sequelae is similar in male and female mice.

Sex, gut microbiome, and cardiovascular disease risk

Key differences exist between men and women in the determinants and manifestations of cardiovascular and cardiometabolic diseases. Recently, gut microbiome-host relations have been implicated in cardiovascular disease and associated metabolic conditions; therefore, gut microbiota may be key mediators or modulators driving the observed sexual dimorphism in disease onset and progression. While current evidence regarding pure physiological sex differences in gut microbiome composition is modest, robust research suggests that gut microbiome-dependent metabolites may interact with important biological pathways under sex hormone control, including toll-like receptor and flavin monooxygenase signaling. Here, we review key sex differences in gut microbiome interactions with four primary determinants of cardiovascular disease, impaired glucose regulation, dyslipidemia, hypertension, and obesity. Through this process, we propose important sex differences in downstream metabolic pathways that may be at the interface of the gut microbiome and cardiovascular disease.

The relationship between circulating testosterone and inflammatory cytokines in men

Testosterone is the predominant gonadal androgen in men. Low testosterone levels are found to be associated with an increased in metabolic risk and systematic inflammation. Since adipose tissue is a source of inflammatory cytokines, testosterone may regulate inflammation by acting on adipose tissue. This review aimed to explore the role of testosterone in inflammation and its mechanism of action. Both animal studies and human studies showed that (1) testosterone deficiency was associated with an increase in pro-inflammatory cytokines; (2) testosterone substitution reduced pro-inflammatory cytokines. The suppression of inflammation by testosterone were observed in patients with coronary artery disease, prostate cancer and diabetes mellitus through the increase in anti-inflammatory cytokines (IL-10) and the decrease in pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α). Despite these, some studies also reported a non-significant relationship. In conclusion, testosterone may possess anti-inflammatory properties but its magnitude is debatable. More evidence is needed to validate the use of testosterone as a marker and in the management of chronic inflammatory diseases.

Intrahost Selection Pressure Drives Equine Arteritis Virus Evolution during Persistent Infection in the Stallion Reproductive Tract

Equine arteritis virus (EAV) is the causative agent of equine viral arteritis (EVA), a reproductive and respiratory disease of horses. Following natural infection, 10 to 70% of infected stallions can become carriers of EAV and continue to shed virus in the semen. In this study, sequential viruses isolated from nasal secretions, buffy coat cells, and semen of seven experimentally infected and two naturally infected EAV carrier stallions were deep sequenced to elucidate the intrahost microevolutionary process after a single transmission event. Analysis of variants from nasal secretions and buffy coat cells lacked extensive positive selection; however, characteristics of the mutant spectra were different in the two sample types. In contrast, the initial semen virus populations during acute infection have undergone a selective bottleneck, as reflected by the reduction in population size and diversifying selection at multiple sites in the viral genome. Furthermore, during persistent infection, extensive genome-wide purifying selection shaped variant diversity in the stallion reproductive tract. Overall, the nonstochastic nature of EAV evolution during persistent infection was driven by active intrahost selection pressure. Among the open reading frames within the viral genome, ORF3, ORF5, and the nsp2-coding region of ORF1a accumulated the majority of nucleotide substitutions during persistence, with ORF3 and ORF5 having the highest intrahost evolutionary rates. The findings presented here provide a novel insight into the evolutionary mechanisms of EAV and identified critical regions of the viral genome likely associated with the establishment and maintenance of persistent infection in the stallion reproductive tract.IMPORTANCE EAV can persist in the reproductive tract of infected stallions, and consequently, long-term carrier stallions constitute its sole natural reservoir. Previous studies demonstrated that the ampullae of the vas deferens are the primary site of viral persistence in the stallion reproductive tract and the persistence is associated with a significant inflammatory response that is unable to clear the infection. This is the first study that describes EAV full-length genomic evolution during acute and long-term persistent infection in the stallion reproductive tract using next-generation sequencing and contemporary sequence analysis techniques. The data provide novel insight into the intrahost evolution of EAV during acute and persistent infection and demonstrate that persistent infection is characterized by extensive genome-wide purifying selection and a nonstochastic evolutionary pattern mediated by intrahost selective pressure, with important nucleotide substitutions occurring in ORF1a (region encoding nsp2), ORF3, and ORF5.

Microenvironmental signals govern the cellular identity of testicular macrophages

Testicular macrophages (TM) comprise the largest immune cell population in the mammalian testis. They are characterized by a subdued proinflammatory response upon adequate stimulation, and a polarization toward the immunoregulatory and immunotolerant M2 phenotype. This enables them to play a relevant role in supporting the archetypical functions of the testis, namely spermatogenesis and steroidogenesis. During infection, the characteristic blunted immune response of TM reflects the need for a delicate balance between a sufficiently strong reaction to counteract invading pathogens, and the prevention of excessive proinflammatory cytokine levels with the potential to disturb or destroy spermatogenesis. Local microenvironmental factors that determine the special phenotype of TM have just begun to be unraveled, and are discussed in this review.