Inflammation In Males Research Articles

Sex, cells, and metabolism: Androgens temper Th17-mediated immunity.

Sex-based differences in autoimmune disease susceptibility have long been recognized, prompting investigations into how sex hormones influence immunity. Recent advances suggest that hormones may shape immune responses by altering cellular metabolism. In this issue of the JCI, Chowdhury et al. authenticates this model, showing that androgen receptor signaling modulates T helper 17 (Th17) cell metabolism, specifically glutaminolysis, reducing airway inflammation in males. This work provides insight into sex-specific regulation of immunity, highlighting the interplay between hormones, metabolism, and immune function. The findings raise intriguing questions about how hormonal fluctuations affect immunity and how sex-specific metabolic pathways might be leveraged for targeted therapies in autoimmune diseases.

Polystyrene nanoplastics alter intestinal toxicity of 2,4-DTBP in a sex-dependent manner in zebrafish (Danio rerio)

Nanoplastics (NPs) and 2,4-di-tert-butylphenol (2,4-DTBP) are ubiquitous emerging environmental contaminants detected in aquatic environment. While the intestinal toxicity of 2,4-DTBP alone has been studied, its combined effects with NPs remain unclear. Herein, adult zebrafish were exposed to 80 nm polystyrene nanoplastics (PS-NPs) or/ and 2,4-DTBP for 28 days. With co-exposure of PS-NPs, impact of 2,4-DTBP on feeding capacity and intestinal histopathology was enhanced in males while attenuated in females. Addition of PS-NPs significantly decreased the uptake of 2,4-DTBP in females, while the intestinal concentrations of 2,4-DTBP were not different between the sexes in co-exposure groups. Furthermore, lower intestinal pH and higher contents of digestive enzymes were detected in male fish, while bile acid was significantly increased in co-exposed females. In addition, co-exposure of PS-NPs stimulated female fish to remodel microbial composition to potentially enhance xenobiotics degradation, while negative Aeromonas aggravated inflammation in males. These results indicated that in the presence of PS-NPs, the gut microenvironment in females can facilitate the detoxification of 2,4-DTBP, while exaggerating toxiciy in males. Overall, this study demonstrates that toxicological outcomes of NPs-chemical mixtures may be modified by sex-specific physiology and microbiota composition, furthering understanding for environmental risk assessment and management of aquatic environments.

Intermittent Fasting Causes Sex-Specific Effects On Metabolic Switching And Aortic Inflammation In A Mouse Model Of Diet-Induced Metabolic Syndrome

Metabolic syndrome (MetS) is a complex multifactorial disease that increases the risk for cardiovascular disease. Despite various treatment strategies, such as restrictive caloric intake and drug therapies, MetS remains challenging to manage. Intermittent fasting (IF) has been proposed as an alternative to traditional treatment as a means of MetS management. However, the sex-specific responses to intermittent fasting during MetS are unclear. Using a mouse model of diet-induced MetS, we characterised the sex-specific effects of IF on metabolic disturbances and aortic inflammation. Six-week-old male and female C57BL/6 mice were fed either a high-fat diet (43% kcal) with high-sugar and high-salt (10% high-fructose corn syrup and 0.9% NaCl in drinking water; HFSS), or normal control diet (NCD). After 10 weeks, mice were randomly assigned to ad libitum (AL) feeding or IF (16 hours/day) for 10 weeks. Physiological parameters were measured during the diet regime and aortic inflammation was measured at endpoint using flow cytometry. HFSS feeding increased bodyweight and fasting blood glucose in both sexes ( P < 0.05), which were reversed by IF irrespective of diet or sex ( P < 0.05). IF increased fasting blood ketones in HFSS-fed females (vs. HFSS-AL females; P < 0.05), but not in HFSS males. Despite HFSS-induced MetS in both sexes, aortic proinflammatory monocytes (CD11b+Ly6CHi), patrolling monocytes (CD11b+Ly6CLo) and macrophages (CD11b+F4/80+) were increased in males mice only. IF reduced proinflammatory monocytes and macrophages in HFSS-IF males as well CD4+ and CD8+ T cells (vs. HFSS-AL males, P<0.05). In summary, IF improved HFSS-induced metabolic disturbances in both sexes, yet metabolic switching (ketosis) was only observed in females. Moreover, HFSS induced aortic inflammation in males only, highlighting the sexual dimorphisms in vascular inflammation during MetS. Our study is the first to report that intermittent fasting reduces aortic inflammation in metabolic syndrome. Further studies are underway to determine the downstream effects of aortic inflammation on end-organs such as the kidneys and liver. National Health and Medical Research Council, Graduate Women Victoria, The Jack Brockoff Foundation. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Prolactin inhibits or stimulates the inflammatory response of joint tissues in a cytokine-dependent manner.

The close association between rheumatoid arthritis (RA), sex, reproductive state, and stress has long linked prolactin (PRL) to disease progression. PRL has both proinflammatory and anti-inflammatory outcomes in RA, but responsible mechanisms are not understood. Here, we show that PRL modifies in an opposite manner the proinflammatory actions of IL-1β and TNF-α in mouse synovial fibroblasts (SF) in culture. Both IL-1β and TNF-α upregulated the metabolic activity and the expression of proinflammatory factors (Il1b, Inos, and Il6) via the activation of the NF-κB signaling pathway. However, IL-1β increased and TNF-α decreased the levels of the long PRL receptor isoform in association with dual actions of PRL on SF inflammatory response. PRL reduced the proinflammatory effect and activation of NF-κB by IL-1β but increased TNF-α-induced inflammation and NF-κB signaling. The double-faceted role of PRL against the two cytokines manifested also in vivo. IL-1β or TNF-α with or without PRL were injected into the knee joints of healthy mice and joint inflammation was monitored after 24 hours. IL-1β and TNF-α increased the joint expression of proinflammatory factors and the infiltration of immune cells. PRL prevented the actions of IL-1β but was either inactive or further increased the proinflammatory effect of TNF-α. We conclude that PRL exerts opposite actions on joint inflammation in males and females that depend on specific proinflammatory cytokines, the level of the PRL receptor, and the activation of NF-κB signaling. Dual actions of PRL may help balance joint inflammation in RA and provide insights for development of new treatments.

The Epigenetic Link of Perinatal BMI to Maternal Phenotype and Fetal Heart Rate

Obesity is a metabolic stressor associated with a suboptimal physiological milieu including an inflammatory state and a dysregulated stress axis. Perinatal maternal BMI impacts pregnancy and birth outcomes along with child metabolic and neurodevelopmental health that are believed to be mediated by epigenetic mechanisms. Our research examines the impacts of pre-pregnancy BMI in a cohort of healthy pregnancies (n=187); first, by characterizing maternal phenotype throughout pregnancy, including her stress physiology (diurnal salivary cortisol), inflammatory status (blood cytokine levels), perinatal depression (EPDS scores), and the underlying epigenetic signature (DNA methylation) in blood that could mediate these effects. Second, we examine the effects of pre-pregnancy BMI on fetal heart rate measurements as an early marker of programming effects of altered autonomic nervous system and the associated placental DNA methylation with a focus on sex-dimorphic effects. Finally, we explore the impact of increasing the allostatic load of high BMI with stress, which was phenotyped in women early in pregnancy driven by data with 27 variables assessing psychological and physical health, on differential placental DNA methylation. To date: regional analysis revealed about 4500 differentially methylated regions (DMR) overall in response to high BMI. Gene ontology enrichment analysis revealed that DM genes annotated to these DMRs were enriched for biological processes involving inflammation in males and RNA silencing in females. This work highlights that the metabolic stress associated with BMI could leave a molecular fingerprint that mediate other maternal physiological and psychological outcomes, which in turn program the fetal neurodevelopmental outcomes.

Consumption of kefir made with traditional microorganisms resulted in greater improvements in LDL cholesterol and plasma markers of inflammation in males when compared to a commercial kefir: a randomized pilot study.

Kefir has long been associated with health benefits; however, recent evidence suggests that these benefits are dependent on the specific microbial composition of the kefir consumed. This study aimed to compare how consumption of a commercial kefir without traditional kefir organisms and a pitched kefir containing traditional organisms affected plasma lipid levels, glucose homeostasis, and markers of endothelial function and inflammation in males with elevated LDL cholesterol. We utilized a crossover design in n = 21 participants consisting of two treatments of 4 weeks each in random order separated by a 4-week washout. Participants received either commercial kefir or pitched kefir containing traditional kefir organisms for each treatment period. Participants consumed 2 servings of kefir (350 g) per day. Plasma lipid profile, glucose, insulin, markers of endothelial function, and inflammation were measured in the fasting state before and after each treatment period. Differences within each treatment period and comparison of treatment delta values were performed using paired t tests and Wilcoxon signed-rank test, respectively. When compared to baseline, pitched kefir consumption reduced LDL-C, ICAM-1, and VCAM-1, while commercial kefir consumption increased TNF-α. Pitched kefir consumption resulted in greater reductions in IL-8, CRP, VCAM-1, and TNF-α when compared to commercial kefir consumption. These findings provide strong evidence that microbial composition is an important factor in the metabolic health benefits associated with kefir consumption. They also provide support for larger studies examining these to assess whether traditional kefir organisms are necessary to confer health benefits to individuals at risk of developing cardiovascular disease.

Association Between Serum Bicarbonate Levels and Prediabetes and Subclinical Inflammation in Young Healthy Adults: A Cross-sectional Study.

Low bicarbonate, a hallmark of metabolic acidosis is associated with various diseases. This study investigated associations between bicarbonate levels with prediabetes and subclinical inflammation among healthy young adults in Qatar. A cross-sectional study was carried out with 825 participants aged 18-40 years, devoid of any known comorbidities, using data from the Qatar Biobank. For each participant, blood samples were taken for measurements of bicarbonate, prediabetes, and subclinical inflammation biomarkers. Prediabetes was defined using HbA1c between 5.7 and 6.4% and subclinical inflammation was defined using monocyte to high density lipoprotein (HDL) cholesterol ratio (MHR). Associations between bicarbonate levels and the outcomes were analyzed using multivariable linear and logistic regression and then stratified by gender. A total of 825 participants with mean age 29.2 years (5.9) of which 365 (44.2%) were males. After multivariable logistic regression, each unit increase in serum bicarbonate was associated with a 17% decreased risk of prediabetes (OR: 0.83, 95%CI: 0.70-0.99, p=0.034), in males but no association was observed for females. Similarly, after multivariable linear regression, a unit increase in serum bicarbonate was associated with a 0.18 unit decrease in MHR (beta -0.18, 95%CI: -0.29, -0.07, p=0.002), again with no association observed in females. In a healthy young adult population, higher serum bicarbonate levels were inversely associated with both prediabetes and subclinical inflammation in males, but not in females.

Response Variability to Drug Testing in Two Models of Chemically Induced Colitis.

The lack of knowledge regarding the pathogenesis of IBD is a challenge for the development of more effective and safer therapies. Although in vivo preclinical approaches are critical for drug testing, none of the existing models accurately reproduce human IBD. Factors that influence the intra-individual response to drugs have barely been described. With this in mind, our aim was to compare the anti-inflammatory efficacy of a new molecule (MTADV) to that of corticosteroids in TNBS and DSS-induced colitis mice of both sexes in order to clarify further the response mechanism involved and the variability between sexes. The drugs were administered preventively and therapeutically, and real-time bioluminescence was performed for the in vivo time-course colitis monitoring. Morphometric data were also collected, and colonic cytokines and acute plasma phase proteins were analyzed by qRT-PCR and ELISA, respectively-bioluminescence images correlated with inflammatory markers. In the TNBS model, dexamethasone worked better in females, while MTADV improved inflammation in males. In DSS-colitis, both therapies worked similarly. Based on the molecular profiles, interaction networks were constructed to pinpoint the drivers of therapeutic response that were highly dependent on the sex. In conclusion, our results suggest the importance of considering sex in IBD preclinical drug screening.

Acute and sub-chronic toxicities assessment of methanol bark extract of Hypericum roeperianum in rats

• Oral acute and sub-chronic toxicities of Hypericum roeperianum methanolic bark extract were evaluated in rats. • No major signs of toxicity were observed in the liver and kidneys. • Slight signs of toxicity were observed at a dose of 1000 mg/kg body weight/day. • Hypericum roeperianum bark is safe at lower doses (250 and 500 mg/kg body weight). The methanolic crude extract of Hypericum roeperianum bark has previously demonstrated interesting cytotoxic properties on panels of human and animal cancer cell lines, involving multi-drug resistant phenotypes. We report here our investigations, which consisted of evaluating the toxicological effects of this plant in experimental animals, Wistar rats. A single oral dose of 5000 mg/kg body weight followed by clinical observations for 14 days was used to assess the acute toxicity of the crude extract of the plant in female rats. For the evaluation of sub-chronic toxicity, repeated oral administration of 250 mg/kg, 500 mg/kg, and 1000 mg/kg body weight was given to the different experimental groups of rats, whereas no treatment was given to the control group. After 28 days of treatment, the animals were sacrificed for hematological and biochemical studies. At the end of the acute toxicity study, we recorded no deaths of rats and no signs of toxicity. Therefore, the median lethal dose (LD 50 ) of H. roeperianum crude extract is greater than 5000 mg/kg body weight. Sub-chronic oral toxicity investigations of the plant showed significant dose-dependent variations in some biochemical parameters, notably LDL cholesterol, creatinine, and alkaline phosphatase, in favour of rats treated with crude extract of H. roeperianum . The hematological profiles showed sometimes significant and sometimes non-significant dose-dependent variations in some parameters. Histopathological analyses revealed slight hepatic inflammation in males treated at 1000 mg/kg body weight. These results suggest that a single high dose of up to 5000 mg/kg of H. roeperianum bark extract is not as toxic as repeated doses of 250, 500, and 1000 mg/kg body weight. However, repeated doses of 1000 mg/kg body weight of H. roeperianum crude extract may show slight signs of toxicity in some organs; it is the case with the liver.

Resveratrol treatment does not reduce arterial inflammation in males at risk of type 2 diabetes: a randomized crossover trial.

Resveratrol has shown promising anti-inflammatory effects in in vitro and animal studies. We aimed to investigate this effect on arterial inflammation in vivo. This was an additional analysis of a double-blind randomized crossover trial which included eight male subjects with decreased insulin sensitivity who underwent an 18F-fluoroxyglucose (18F-FDG) PET/CT after 34 days of placebo and resveratrol treatment (150 mg/day). 18F-FDG uptake was analyzed in the carotid arteries and the aorta, adipose tissue regions, spleen, and bone marrow as measures for arterial and systemic inflammation. Maximum target-to-background ratios (TBRmax) were compared between resveratrol and placebo treatment with the non-parametric Wilcoxon signed-rank test. Median values are shown with their interquartile range. Arterial 18F-FDG uptake was non-significantly higher after resveratrol treatment (TBRmax all vessels 1.7 (1.6-1.7)) in comparison to placebo treatment (1.5 (1.4-1.6); p=0.050). Only in visceral adipose tissue, the increase in 18F-FDG uptake after resveratrol reached statistical significance (p=0.024). Furthermore, CRP-levels were not significantly affected by resveratrol treatment (p=0.091). Resveratrol failed to attenuate arterial or systemic inflammation as measured with 18F-FDG PET in subjects at risk of developing type 2 diabetes. However, validation of these findings in larger human studies is needed.

Abstract P174: Sex Differences In The Pro-hypertensive Effect Of Carnitine, The Precursor Of Gut-derived Metabolite TMAO

Recent evidence reports sexually divergent mechanisms that differentially drive the severity of hypertension. Our data show that female Dahl Salt-Sensitive (SS) rats are significantly protected from salt-induced hypertension and renal injury and have stark differences in gut microbiota composition compared to males. Gut-derived metabolites are increasingly being recognized as mechanistic links between the gut microbiota and hypertension. One such metabolite is trimethylamine N-oxide (TMAO), which is derived from the bacterial metabolism of carnitine and is gaining notoriety for its role in cardiovascular disease. Metabolomics analysis in high salt-fed SS rats revealed a trend for increased TMAO (1.3-fold, p=0.11) in the serum of males compared to females (n=6). TMAO appears to be specifically derived from gut bacteria since oral antibiotic treatment nearly eliminated circulating TMAO levels in both males and females (99.3% and 88.9% reduction, respectively; p<0.001). Interestingly, antibiotic treatment reduced salt-sensitive hypertension in males but not females. There was also a corresponding increase in the TMAO precursor carnitine (1.9-fold, p<0.01) in the serum of males versus females. Thus, we hypothesized that administration of carnitine (400 mg/kg/day) in the drinking water would exacerbate salt-sensitive hypertension, renal damage, and gut inflammation in male and female SS rats challenged with high salt (4% NaCl). There was a trend for carnitine treatment to exacerbate mean arterial pressure in both males (160±9 vs 146±2 mmHg, n=4-6, p=0.22) and females (155±6 vs 139±2 mmHg, n=2, p=0.14) compared to vehicle. Despite elevated pressure in both sexes, carnitine-treated males exhibited greater increases in albuminuria (340±136 vs 194±29 mg/day, carnitine vs vehicle, p=0.28) than females (55±33 vs 26±5 mg/day). Carnitine treatment also significantly increased the number of CD3+ T cells in the colonic lamina propria (24.3±6.0 vs 2.4±0.5 x 10 6 cells/g tissue, n=5, p<0.05) of male rats compared to vehicle. Together, these data identify gut microbiota-mediated carnitine/TMAO metabolism as a potentially detrimental pathway that promotes greater salt-sensitivity, renal damage, and gut inflammation in males versus females.

Role of Connexin 43 in an Inflammatory Model for TMJ Hyperalgesia.

Temporomandibular joint disorders (TMD) consist of a heterogeneous group of conditions that present with pain in the temporomandibular joint (TMJ) region and muscles of mastication. This project assessed the role of connexin 43 (Cx43), a gap junction protein, in the trigeminal ganglion (TG) in an animal model for persistent inflammatory TMJ hyperalgesia. Experiments were performed in male and female rats to determine if sex differences influence the expression and/or function of Cx43 in persistent TMJ hyperalgesia. Intra-TMJ injection of Complete Freund's Adjuvant (CFA) caused a significant increase in Cx43 expression in the TG at 4 days and 10 days post-injection in ovariectomized (OvX) female rats and OvX females treated with estradiol (OvXE), while TG samples in males revealed only marginal increases. Intra-TG injection of interference RNA for Cx43 (siRNA Cx43) 3 days prior to recording, markedly reduced TMJ-evoked masseter muscle electromyographic (MMemg) activity in all CFA-inflamed rats, while activity in sham animals was not affected. Western blot analysis revealed that at 3 days after intra-TG injection of siRNA Cx43 protein levels for Cx43 were significantly reduced in TG samples of all CFA-inflamed rats. Intra-TG injection of the mimetic peptide GAP19, which inhibits Cx43 hemichannel formation, greatly reduced TMJ-evoked MMemg activity in all CFA-inflamed groups, while activity in sham groups was not affected. These results revealed that TMJ inflammation caused a persistent increase in Cx43 protein in the TG in a sex-dependent manner. However, intra-TG blockade of Cx43 by siRNA or by GAP19 significantly reduced TMJ-evoked MMemg activity in both males and females following TMJ inflammation. These results indicated that Cx43 was necessary for enhanced jaw muscle activity after TMJ inflammation in males and females, a result that could not be predicted on the basis of TG expression of Cx43 alone.

Sex differences in systemic bone and muscle loss following femur fracture in mice.

Fracture induces systemic bone loss in mice and humans, and a first (index) fracture increases the risk of future fracture at any skeletal site more in men than women. The etiology of this sex difference is unknown, but fracture may induces a greater systemic bone loss response in men. Also sex differences in systemic muscle loss after fracture have not been examined. We investigated sex differences in systemic bone and muscle loss after transverse femur fracture in 3-month-old male and female C57BL/6 J mice. Whole-body and regional bone mineral content and density (BMC and BMD), trabecular and cortical bone microstructure, muscle contractile force, muscle mass, and muscle fiber size were quantified at multiple time points postfracture. Serum concentrations of inflammatory cytokines (IL-1β, IL-6, and TNF-α) were measured 1-day postfracture. One day postfracture, IL-6 and Il-1B were elevated in fracture mice of both sexes, but TNF-α was only elevated in male fracture mice. Fracture reduced BMC, BMD, and trabecular bone microstructural properties in both sexes 2 weeks postfracture, but declines were greater in males. Muscle contractile force, mass, and fiber size decreased primarily in the fractured limb at 2 weeks postfracture and females showed a trend toward greater muscle loss. Bone and muscle properties recovered by 6 weeks postfracture. Overall, postfracture systemic bone loss is greater in men, which may contribute to sex differences in subsequent fracture risk. In both sexes, muscle loss is primarily confined to the injured limb and fracture may induce greater inflammation in males.

Increased Omega-3 Fatty Acid Intake Is Inversely Associated with Subclinical Inflammation in Healthy Elderly Men, Based on the 2015-2018 Korean National Health and Nutrition Examination Survey.

(1) Background: Subclinical inflammation as a risk factor of cardiovascular diseases was clinically measured using C-reactive protein (CRP) level. (2) Methods: This study was cross-sectionally designed based the 2015–2018 Korean National Health and Nutrition Examination Survey (KNHANES). The ratio of daily omega-3 fatty acids to energy intake (ω3FA ratio) was classified into four quartile groups (Q1, <0.3%; Q2, 0.3%–<0.6%; Q3, 0.6%–<1.0%; and Q4, ≥1.0% in both sexes). Logistic regression analysis was conducted to investigate the association between the ω3FA ratio and subclinical inflammation defined as CRP levels ≥3 mg/dL. (3) Results: The ω3FA ratio in subjects without and with subclinical inflammation was 0.8% and 0.7% in men (p-value = 0.001), and 0.8% and 0.8% in women (p-value = 0.491), respectively. The prevalence of subclinical inflammation in males decreased with increasing quartile of ω3FA ratio (12.9%, 9.6%, 7.4%, and 7.7%, p-value = 0.033), while female prevalence was not significant among quartile groups. Compared to Q1, odds ratios (95% confidence intervals) for subclinical inflammation of Q2, Q3, and Q4 were 0.740 (0.465–1.177), 0.564 (0.341–0.930), and 0.549 (0.317–0.953) in males, and 1.066 (0.653–1.741), 1.105 (0.600–1.718), and 0.934 (0.556–1.571) in females after full adjustment. (4) Conclusion: The ω3FA ratio is associated with subclinical inflammation in men.

Delayed PARP-1 Inhibition Alleviates Post-stroke Inflammation in Male Versus Female Mice: Differences and Similarities.

Post-stroke inflammation is almost involved in the whole process of stroke pathogenesis, which serves as a prime target for developing new stroke therapies. Despite known sex differences in the incidence and outcome of stroke, few preclinical or clinical studies take into account sex bias in treatment. Recent evidence suggests that poly (ADP-ribose) polymerase (PARP)-1 inhibitor exerts sex-specific neuroprotection in the ischemic stroke. This study was aimed to investigate the effects of delayed PARP-1 inhibition on post-stroke inflammation and possible sexual dimorphism, and explore the possible relevant mediators. In male and female C57BL/6 mice subjected to transit middle cerebral artery occlusion (MCAO), we found that delayed treatment of PARP-1 inhibitor at 48 h following reperfusion could comparably alleviate neuro-inflammation at 72 h after stroke. Whereas, more remarkable reduction of iNOS and MMP9 induced by PARP-1 inhibition were found in male MCAO mice, and the improvement of behavioral outcomes was more prominent in male MCAO mice. In addition, we further identified that PARP-1 inhibitor might equivalently suppress microglial activation in males and females in vivo and in vitro. With proteomic analysis and western blotting assay, it was found that stroke-induced peroxiredoxin-1 (Prx1) expression was significantly affected by PARP-1 inhibition. Interestingly, injection of recombinant Prx1 into the ischemic core could block the anti-inflammatory effects of PARP-1 inhibitor in the experimental stroke. These findings suggest that PARP-1 inhibitor has effects on regulating microglial activation and post-stroke inflammation in males and females, and holds promise as a novel therapeutic agent for stroke with extended therapeutic time window. Efforts need to be made to delineate the actions of PARP-1 inhibition in stroke, and here we propose that Prx1 might be a critical mediator.

Regulatory T Cells Beyond Autoimmunity: From Pregnancy to Cancer and Cardiovascular Disease.

The evolution of the full range of functions of regulatory T cells (Treg) coincides with the evolution of mammalian pregnancy. Accordingly, Treg function has been shown to be crucial for maternal-fetal tolerance and implantation. As reproduction is a key point of selective pressure, mammalian pregnancy may represent an evolutionary driver for the development of Treg. Yet beyond the chronological boundaries of mammalian pregnancy, several key physiological and pathological events are being gradually uncovered as involving the immunomodulating functions of Treg cells. These include autoimmunity, age-related inflammation in males and in post-menopausal females, but also oncological and cardiovascular diseases. The latter two sets of diseases collectively compose the main causes of mortality world-wide. Emerging data point to Treg-modulable effects in these diseases, in a departure from the relatively narrower perceived role of Treg as master regulators of autoimmunity. Yet recent evidence also suggests that changes in intestinal microbiota can affect the above pathological conditions. This is likely due to the finding that, whilst the presence and maintenance of intestinal microbiota requires active immune tolerance, mediated by Treg, the existence of microbiota per se profoundly affects the polarization, stability, and balance of pro- and anti-inflammatory T cell populations, including Treg and induced Treg cells. The study of these “novel,” but possibly highly relevant from an ontogenesis perspective, facets of Treg function may hold great potential for our understanding of the mechanisms underlying human disease.

Endothelial Mineralocorticoid Receptors Contribute to Vascular Inflammation in Atherosclerosis in a Sex-Specific Manner.

MR (mineralocorticoid receptor) activation is associated with cardiovascular ischemia in humans. This study explores the role of the MR in atherosclerotic mice of both sexes and identifies a sex-specific role for endothelial cell (EC)-MR in vascular inflammation. Approach and Results: In the AAV-PCSK9 (adeno-associated virus-proprotein convertase subtilisin/kexin type 9) mouse atherosclerosis model, MR inhibition attenuated vascular inflammation in males but not females. Further studies comparing male and female littermates with intact MR or EC-MR deletion revealed that although EC-MR deletion did not affect plaque size in either sex, it reduced aortic arch inflammation specifically in male mice as measured by flow cytometry. Moreover, MR-intact females had larger plaques but were protected from vascular inflammation compared with males. Intravital microscopy of the mesenteric vasculature demonstrated that EC-MR deletion attenuated TNFα (tumor necrosis factor α)-induced leukocyte slow rolling and adhesion in males, while females exhibited fewer leukocyte-endothelial interactions with no additional effect of EC-MR deletion. These effects corresponded with decreased TNFα-induced expression of the endothelial adhesion molecules ICAM-1 (intercellular adhesion molecule-1) and E-selectin in males with EC-MR deletion compared with MR-intact males and females of both genotypes. These observations were also consistent with MR and estrogen regulation of ICAM-1 transcription and E-selectin expression in primary cultured mouse ECs and human umbilical vein ECs. In male mice, EC-MR deletion attenuates leukocyte-endothelial interactions, plaque inflammation, and expression of E-selectin and ICAM-1, providing a potential mechanism by which the MR promotes vascular inflammation. In females, plaque inflammation and leukocyte-endothelial interactions are decreased relative to males and EC-MR deletion is not protective.

Sex-specific maternofetal innate immune responses triggered by group B Streptococci

Group B Streptococcus (GBS) is one of the most common bacteria isolated in human chorioamnionitis, which is a major risk factor for premature birth and brain injuries. Males are at greater risk than females for developing lifelong neurobehavioural disorders, although the origins of this sex bias remain poorly understood. We previously showed that end-gestational inflammation triggered by GBS led to early neurodevelopmental impairments mainly in the male rat progeny. Identifying key inflammatory players involved in maternofetal immune activation by specific pathogens is critical to develop appropriate novel therapeutic interventions. We aimed to map out the GBS-induced profile of innate immune biomarkers in the maternal-placental-fetal axis, and to compare this immune profile between male and female tissues. We describe here that the GBS-induced immune signalling involved significantly higher levels of interleukin (IL)-1β, cytokine-induced neutrophil chemoattractant-1 (CINC-1/CXCL1) and polymorphonuclear cells (PMNs) infiltration in male compared to female maternofetal tissues. Although male – but not female – fetuses presented increased levels of IL-1β, fetuses from both sexes in-utero exposed to GBS had increased levels of TNF-α in their circulation. Levels of IL-1β detected in fetal sera correlated positively with the levels found in maternal circulation. Here, we report for the first time that the maternofetal innate immune signalling induced by GBS presents a sexually dichotomous profile, with more prominent inflammation in males than females. These sex-specific placental and fetal pro-inflammatory responses are in keeping with the higher susceptibility of the male population for preterm birth, brain injuries and neurodevelopmental disorders such as cerebral palsy and autism spectrum disorders.

SUN-105 Females Have Reduced Meta-Inflammation in Two States of Increased Adiposity, Obesity, and Aging

Obesity is a global health epidemic, closely associated with cardiovascular diseases (CVD), hypertension, type 2 diabetes, and atherosclerosis. Obese adipose tissue is a site and source for inflammation that is strongly associated with these metabolic diseases. In obese mice models, males exhibit profound adipose tissue macrophage (ATM) accumulation in gonadal white adipose tissue (GWAT) linked to insulin resistance, while females are protected even with enhanced adiposity. This dampened inflammation may directly explain reduced metabolic and cardiovascular disease in young women. However, it is not clear what metabolic and inflammatory responses occur in post-menopausal models. We hypothesized an increased inflammatory response would occur in obese older females. We challenged male and female C57Bl6/j mice to 16-24 weeks of 60% high fat diet (HFD) starting at 6 weeks of age (young) or 10 month of age (old). Animal body weights and metabolic depot (adipose and liver) weights were measured at the completion of diet challenge. Flow cytometry was used to determine ATM populations in visceral (GWAT) compared to subcutaneous inguinal WAT (IWAT). Lipolysis was stimulated with a beta3 adrenergic receptor (ADRB3) agonist CL-316, 243 and free fatty acids (FFA), glycerol, and triglyceride (TG) levels assessed in serum and liver. Obesity in young mice led to fat accumulation in GWAT and IWAT of both males and females. In old male animals, fat pads did not expand, and liver weights were as a result larger than in females. Both young and old females had reduced adipose inflammation compared to males. ADRB3 activation had no effect on adipose tissue weights but significantly increased liver weights in obese young females. Obese CL treated young and old female mice showed elevated FFA compared to levels induced in males. Lipolysis promoted appearance of crown like structures (CLS) in both obese young and old males and females, due to CD11c- ATM accumulation. Obesity during aging continues to lead to enhanced inflammation in males along with steatosis but females continue to be protected with appropriate storage of fatty acids with very little induced inflammation. Sex differences in inflammation that persist in aging demonstrate that differences in meta-inflammation may explain sex differences in metabolic and cardiovascular diseases regardless of age and need to be further explored for targeted treatment strategies.

Sex Differences in the Role of the Endothelial Mineralocorticoid Receptor in Vascular Inflammation in Atherosclerosis

BackgroundAtherosclerosis is a vascular inflammatory condition that underlies nearly all myocardial infarctions (MI) and ischemic strokes and is the leading cause of death in America for men and women. Prior to menopause, women are protected relative to men from the rupture of atherosclerotic plaques that leads to MI, through unknown mechanisms. Inflammation of atherosclerotic plaques is a risk factor for rupture; therefore it is critical to understand the mechanisms driving plaque inflammation to prevent downstream adverse cardiovascular events. Clinical data indicate that serum levels of the hormone aldosterone correlate with risk of MI and death, and animal models demonstrate a role for the aldosterone‐binding mineralocorticoid receptor (MR) in atherosclerosis in males. However, the role of the MR in atherosclerosis in females has never been studied. This study explores the role of the MR in atherosclerosis in both sexes and characterizes a sex‐specific role of endothelial cell MR (EC‐MR) in vascular inflammation.ResultsIn a mouse atherosclerosis model induced by viral expression of active human PCSK9, MR inhibition with spironolactone reduced inflammation in males but not females. To investigate the mechanism for this sex difference, atherosclerosis and vascular inflammation were assessed in male and female mice with EC‐MR deletion compared to MR‐intact littermates. EC‐MR deletion did not affect plaque size in either sex but reduced plaque inflammation specifically in male mice, as quantified by flow cytometry of the aortic arch. Female MR‐intact mice had larger but less inflamed plaques relative to males, and the protection from inflammation was abolished with EC‐MR deletion in females. In human cultured ECs, spironolactone reduced leukocyte adhesion and promoter activity and protein expression of intracellular adhesion molecule‐1, only in the absence of estrogen. Further studies are underway to characterize the contribution of EC‐MR to leukocyte rolling and adhesion, using novel intravital microscopy methods.ConclusionMR inhibition attenuates atherosclerotic plaque inflammation specifically in male mice, with no effect in females. This is mediated by a sex difference in the role of EC‐MR in vascular inflammation. As inflammation is linked with risk of rupture and thrombosis of atherosclerotic plaques, leading to death from cardiovascular ischemia, this study supports targeting of EC‐MR in males to reduce the risk of plaque rupture. Further, this study suggests a new mechanism for differences in the incidence of MI between men and premenopausal women.Support or Funding InformationFunding from NIH/NHLBI HL095590 (to IZJ), AHA EIA18290005 (to IZJ), AHA 17PRE32910003 (to MEM), and NIH/NHLBI F30HL137255 (to MEM).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.