Increased high-density lipoprotein cholesterol levels in mice with XX versus XY sex chromosomes

Serum vitamin C associated with lipids levels in children and adolescents: a national cross-sectional study

BACKGROUND

The relationship between serum vitamin C (sVC) and blood lipids in adolescents in the US has not been thoroughly studied. This study investigates the correlation between sVC and blood lipids among adolescents using data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

Data from the NHANES 2003-2006 and 2017-2018 cycles, encompassing 4,965 participants aged 12-19 years, were analyzed. sVC served as the independent variable and blood lipids as the dependent variables. Multiple linear regression models assessed the relationship between sVC and blood lipids, with subgroup analyses based on sex, age, and race. Additionally, smooth curve fitting and saturation threshold analysis were employed to explore nonlinear relationships.

RESULTS

Adjusted analyses revealed a positive correlation between sVC and high-density lipoprotein cholesterol (HDL-C) (β = 2.77, 95%CI 2.06-3.47), with no significant association with total cholesterol, low-density lipoprotein cholesterol (LDL-C), or triglycerides. This positive correlation persisted across subgroups divided by age, gender, and race (p < 0.05). The nonlinear relationship between sVC and HDL-C was characterized by an inverted U-shaped curve in adolescents aged 12-15 years, males, females, and non-Hispanic Whites.

CONCLUSIONS

This study confirms a positive association between sVC levels and HDL-C in adolescents, suggesting that higher vitamin C intake/status may be associated with a higher HDL-C in adolescents.

Sex Chromosomes and Sex Hormones: Dissecting the Forces That Differentiate Female and Male Hearts

The heart is a highly sex-biased organ, as sex shapes innumerable aspects of heart health and disease. Sex chromosomes and sex hormones -testosterone, progesterone, and estrogen- establish and perpetuate the division between male and female myocardium. Of these differentiating factors, the insulating effects of estrogen have been rigorously interrogated and reviewed, whereas the influence of sex chromosomes, testosterone, and progesterone remains in dispute or ill-defined. Here, we synthesize growing evidence that sex chromosomes and sex hormones substantially bias heart form, function, and dysfunction in a context-dependent fashion. The discrete protective functions ascribed to each of the 3 estrogen receptors are also enumerated. Subsequently, we overview obstacles that have historically discouraged the inclusion of female subjects in basic science such as the impact of the female estrus cycle and reproductive senescence on data reliability and reproducibility. Furthermore, we weigh the utility of several common strategies to intercept and rescue sex-specific protection. Last, we warn of common compounds in animal chow and cell culture that interfere with estrogen signaling. In sum, we survey the controversies and challenges that stem from sex-inclusive cardiovascular research, comparing the possible causes of cardiac sex bias, elucidating sex chromosome or hormone-dependent processes in the heart, describing common lapses that imperil female and male cell and animal work, and illuminating facets of the female heart yet unexplored or still uncertain.

Sex- and trimester-specific impact of gestational co-exposure to organophosphate esters and phthalates on insulin action among preschoolers: Findings from the Ma'anshan birth cohort

INTRODUCTION

Prenatal exposure to organophosphate esters (OPEs) and phthalic acid esters (PAEs) is ubiquitous among pregnant individuals. However, research exploring the relationship between prenatal co-exposure to OPEs and PAEs and childhood insulin function remains limited.

METHODS

In this study, utilizing data from 2,246 maternal-fetal dyads in the Ma'anshan Birth Cohort, associations between co-exposure to OPEs and PAEs and insulin action were analyzed. Repeated measures of tris (2-chloroethyl) phosphate, six OPE metabolites, and seven PAE metabolites were collected from maternal urine. Homeostasis model assessment of insulin resistance (HOMA-IR) and the insulin action index (IAI) served as outcome measures. After adjusting for potential confounders, the effects of repeated exposure on insulin action were evaluated using generalized estimating equations, while mixture effects were assessed through BayesianKernel Machine Regression and Quantile-Based G-Computation.

RESULTS

The average age of the children at the time of the study was 5.33 years. Repeated measures analysis revealed that prenatal exposure to MEP was positively associated with increased HOMA-IR (β, 0.027; 95 % CI: 0.002, 0.053), while IAI was inversely correlated with rising MEP levels (β, 0.025; 95 % CI: -0.046, -0.004) and MEHHP exposure (β, -0.128; 95 % CI: -0.218, -0.037). Mixed exposure modeling further indicated that co-exposure to OPEs and PAEs was positively linked to HOMA-IR (β, 0.058; 95 % CI: 0.001, 0.114) and negatively correlated with IAI (β, -0.054; 95 % CI: -0.097, -0.010), with stronger effects observed during the second trimester. Notably, the association was more pronounced in female children compared to males.

CONCLUSIONS

This study provides the first epidemiological evidence highlighting the pregnancy- and sex-specific links between prenatal co-exposure to OPEs and PAEs and childhood insulin action.

Stress in pregnancy alters hepatic unfolded protein responses in male adult offspring

Stress is considered an independent risk factor for the development of cardiometabolic disorders, especially when it occurs during pregnancy, and it may play an important role in stress-induced fetal programming on the protein-folding homeostasis in hepatic endoplasmic reticulum. The study aimed to determine the effects of prenatal stress on the unfolded protein responses in the liver of male and female offspring of Wistar rats. Pregnant Wistar rats at 90 days old were divided into control and stress groups. The unpredictable stress protocol was performed from the 14th to the 21st day of pregnancy. The offspring of each group were divided into four groups according to sex and intervention. After the lactation period, the dams were anesthetized and euthanized for blood collection to determine plasma corticosterone levels. At 90 days old, the offspring were anesthetized and euthanized for liver tissue collection to measure protein expression of the endoplasmic reticulum stress. Dams submitted to prenatal stress showed an increase in corticosterone levels when compared to the control group. In the male offspring, prenatal stress induced lower body mass at birth and at 90 days compared to control, while females presented lower body mass only at birth. Prenatal stress reduced eIF2α expression in males, while increased p-eIF2α expression similarly in both sexes. Furthermore, only males had a greater p-eIF2α/eIF2α ratio and androgen receptor expression when compared to its respective control group and females. Prenatal stress induced a hepatic programming in the reticulum endoplasmic responses only in males at 90 days old by increasing androgen receptor, eIF2α phosphorylation and activity, while in females stress during pregnancy reduced cHDL and had little impact on hepatic unfolded protein response.

High-density lipoprotein cholesterol and nasal colonization of Staphylococcus aureus: results from the 2001-2004 National Health and Nutrition Examination Survey (NHANES)

BACKGROUND

High-density lipoprotein cholesterol (HDL-C) is negatively associated with infectious diseases, but the relationship between HDL-C and nasal colonization of Staphylococcus aureus is unclear.

OBJECTIVE

To investigate the relationship between HDL-C and nasal colonization of Staphylococcus aureus.

METHODS

The cross-sectional study included 7731 participants from the 2001-2004 National Health and Nutrition Inspection Survey (NHANES) survey cycle who had complete data. After adjusting demographics and lifestyle, we used multivariate logistic regression to analyze the relationship between HDL-C and nasal colonization of Staphylococcus aureus. We also used restricted cubic splines (RCS) to analyze the nonlinear relationship between HDL-C and nasal colonization of Staphylococcus aureus. All the analyses adjusted the relevant covariates.

RESULTS

The mean of HDL-C in this study was 1.38 ± 0.64 mmol/L and the colonization rate of nasal colonization of Staphylococcus aureus was 26.2%. Both unadjusted model (OR = 0.71; 95%CI: 0.62-0.80; P < 0.001) and preliminary adjusted model (model 1: OR = 0.77; 95%CI: 0.67-0.89; P < 0.001) showed a significant negative correlation between HDL-C and nasal colonization of Staphylococcus aureus. After adjusting all variables in model 3, the relationship between HDL-C and nasal colonization of Staphylococcus aureus was still significant and negatively correlated (OR = 0.79; 95%CI: 0.69-0.92; P = 0.002). In addition, through RCS analysis, there was also a significant negative correlation between HDL-C and nasal colonization of Staphylococcus aureus (P for non-linear = 0.034). In subgroup analysis, only gender has a significant impact on this relationship (P for interaction = 0.013). In male, for each additional raising unit of HDL-C, the risk of nasal colonization of Staphylococcus aureus decreased by 38% (OR = 0.62, 95%CI: 0.49-0.79); in female, the relationship was no longer significant. We did not observe the interaction between all the other subgroup analysis results (P for interaction > 0.05).

CONCLUSIONS

We found that HDL-C was negatively correlated with nasal colonization of Staphylococcus aureus, especially in male, even after adjusting for various variables. These findings provide valuable insights into the development of early intervention strategies in people at high risk of infectious diseases.

Lipoprotein Metabolism, Dyslipidemia, and Lipid-Lowering Therapy in Women: A Comprehensive Review

Lipid-lowering therapy (LLT) is a cornerstone of atherosclerotic cardiovascular disease prevention. Although LLT might lead to different reductions in low-density lipoprotein cholesterol (LDL-C) levels in women and men, LLT diminishes cardiovascular risk equally effectively in both sexes. Despite similar LLT efficacy, the use of high-intensity statins, ezetimibe, and proprotein convertase subtilisin/kexin type 9 inhibitors is lower in women compared to men. Women achieve the guideline-recommended LDL-C levels less often than men. Greater cholesterol burden is particularly prominent in women with familial hypercholesterolemia. In clinical practice, women and men with dyslipidemia present with different cardiovascular risk profiles and disease manifestations. The concentrations of LDL-C, lipoprotein(a), and other blood lipids differ between women and men over a lifetime. Dissimilar levels of LLT target molecules partially result from sex-specific hormonal and genetic determinants of lipoprotein metabolism. Hence, to evaluate a potential need for sex-specific LLT, this comprehensive review (i) describes the impact of sex on lipoprotein metabolism and lipid profile, (ii) highlights sex differences in cardiovascular risk among patients with dyslipidemia, (iii) presents recent, up-to-date clinical trial and real-world data on LLT efficacy and safety in women, and (iv) discusses the diverse medical needs of women and men with dyslipidemia and increased cardiovascular risk.

Gender-Affirming Hormone Treatment and Metabolic Syndrome Among Transgender Veterans

Importance

Gender-affirming hormone treatment (GAHT) is a common therapy for transgender individuals to reduce gender dysphoria and improve quality of life. Clarifying the long-term effects of GAHT remains a priority in transgender health research.

Objective

To explore whether sex hormones (estradiol and testosterone) are associated with the development of metabolic syndrome in transgender veterans compared with cisgender veterans.

Design, Setting, and Participants

This retrospective, longitudinal cohort study used International Classification of Diseases, Ninth Revision and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision diagnosis codes for gender dysphoria from the Veterans Health Administration national database to identify transfeminine and transmasculine veterans receiving documented feminizing (estradiol) or masculinizing (testosterone) treatment from January 1, 2006, to December 31, 2019, and for whom the GAHT initiation date and metabolic syndrome component-related data were available. Transgender veterans were matched to cisgender referents.

Exposure

Gender-affirming hormone treatment.

Main Outcomes and Measures

Metabolic syndrome z-scores were calculated based on body mass index, systolic blood pressure, and levels of high-density lipoprotein cholesterol, triglycerides, and blood glucose. Changes in mean z-scores were compared among the transgender and cisgender groups before and after the index date (corresponding to GAHT initiation) using a repeated-measures analysis of variance model.

Results

The cohort included 1290 participants: 645 transgender (494 [38.3%] transfeminine, 151 [11.7%] transmasculine) and 645 cisgender (280 [21.7%] female, 365 [28.3%] male). Mean (SD) age at the index date was 41.3 (13.2) years. Metabolic syndrome z-scores changed significantly over time and differed significantly across groups. Overall, transmasculine veterans had the greatest percentage increase in mean (SEM) z-scores after vs before the index date (298.0% [57.0%]; P < .001), followed by cisgender females (108.3% [27.5%]; P < .001), cisgender males (49.3% [27.5%]; P = .02), and transfeminine persons (3.0% [10.7%]; P = .77).

Conclusions and Relevance

In this cohort study, in both cisgender and transgender veterans, estradiol was associated with reduced metabolic syndrome risk, whereas testosterone was associated with increased risk. However, transmasculine individuals had the greatest risk and transfeminine individuals had the lowest risk of metabolic syndrome associated with these hormones. This is relevant for the management of metabolic syndrome risk factors in cisgender and transgender individuals and to potentially predict the risk of atherosclerotic cardiovascular disease, type 2 diabetes, systolic hypertension, insulin resistance, and nonalcoholic fatty liver disease.

Epigenetic developmental mechanisms underlying sex differences in cancer

Cancer risk is modulated by hereditary and somatic mutations, exposures, age, sex, and gender. The mechanisms by which sex and gender work alone and in combination with other cancer risk factors remain underexplored. In general, cancers that occur in both the male and female sexes occur more commonly in XY compared with XX individuals, regardless of genetic ancestry, geographic location, and age. Moreover, XY individuals are less frequently cured of their cancers, highlighting the need for a greater understanding of sex and gender effects in oncology. This will be necessary for optimal laboratory and clinical cancer investigations. To that end, we review the epigenetics of sexual differentiation and its effect on cancer hallmark pathways throughout life. Specifically, we will touch on how sex differences in metabolism, immunity, pluripotency, and tumor suppressor functions are patterned through the epigenetic effects of imprinting, sex chromosome complement, X inactivation, genes escaping X inactivation, sex hormones, and life history.

Biological sex, sex steroids and sex chromosomes contribute to mouse cardiac aging

After menopause, the incidence of cardiovascular disease rapidly rises in women. The disappearing protection provided by sex steroids is a consequence of the development of many risk factors. Preclinical studies are necessary to understand better the effects of ovarian hormones loss cardiac aging. To mimic menopause in mice and study its consequences, we delayed ovariectomy at 12 months and followed animals for 12 months. Using RNA sequencing, we investigated changes in the myocardial exome with aging. In addition, with four-core genotypes (FCG) transgenic mice, we studied sex chromosome effects on cardiac aging. Heart weight increased from 3 to 24 months (males + 35%, females + 29%). In males, 75% of this increase had occurred at 12 months; in females, only 30%. Gonadectomy of mice at 12 months blocked cardiac hypertrophy in both sexes during the second year of life. The dosage of the X chromosomes did not influence cardiac growth in young and older mice. We performed an RNA sequencing study in young and old mice. We identified new highly expressed genes modulated during aging (Bdh, Myot, Cpxm2, and Slc38a1). The myocardial exome in older animals displayed few differences related to the animal's sex or the presence or absence of sex steroids for a year. We show that the morphological evolution of the heart depends on the biological sex via gonadal sex hormone actions. The myocardial exome of old male and female mice is relatively similar. Our study emphasizes the need to consider sex steroid effects in studying cardiac aging.

Impact of Gestational Exposure to Individual and Combined Per- and Polyfluoroalkyl Substances on a Placental Structure and Efficiency: Findings from the Ma'anshan Birth Cohort

Prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances (PFASs) is inevitable among pregnant women. Nevertheless, there is a scarcity of research investigating the connections between prenatal PFAS exposure and the placental structure and efficiency. Based on 712 maternal-fetal dyads in the Ma'anshan Birth Cohort, we analyzed associations between individual and mixed PFAS exposure and placental measures. We repeatedly measured 12 PFAS in the maternal serum during pregnancy. Placental weight, scaling exponent, chorionic disc area, and disc eccentricity were used as the outcome variables. Upon adjusting for confounders and implementing corrections for multiple comparisons, we identified positive associations between branched perfluorohexane sulfonate (br-PFHxS) and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) with placental weight. Additionally, a positive association was observed between br-PFHxS and the scaling exponent, where a higher scaling exponent signified reduced placental efficiency. Based on neonatal sex stratification, female infants were found to be more susceptible to the adverse effects of PFAS exposure. Mixed exposure modeling revealed that mixed PFAS exposure was positively associated with placental weight and scaling exponent, particularly during the second and third trimesters. Furthermore, br-PFHxS and 6:2 Cl-PFESA played major roles in the placental measures. This study provides the first epidemiological evidence of the relationship between prenatal PFAS exposure and placental measures.

Sex-dependent associations of plasma high-density lipoprotein cholesterol and mortality risk in healthy older men and women: two prospective cohort studies

The relationship between high plasma high-density lipoprotein cholesterol (HDL-C) and cause and mortality are not well established in healthy older people. This study examined the associations between HDL-C levels and mortality in initially healthy older men and women. This analysis included participants from the Aspirin in Reducing Events in the Elderly (ASPREE; n=18,668) trial and a matched cohort from the UK Biobank (UKB; n=62,849 ≥65 years). Cox regression was used to examine hazard ratios between HDL-C categories <1.03 mmol/L, 1.03-1.55 mmol/L (referent category), 1.55-2.07 mmol/L, and >2.07 mmol/L and all-cause, cancer, cardiovascular disease (CVD), and "non-cancer non-CVD" mortality. Genetic contributions were assessed using a polygenic score for HDL-C. Among ASPREE participants (aged 75±5 years), 1836 deaths occurred over a mean follow-up of 6.3±1.8 years. In men, the highest category of HDL-C levels was associated with increased risk of all-cause (HR 1.60, 95% CI 1.26-2.03), cancer (HR 1.37, 95% CI 0.96-2.00), and "non-cancer non-CVD" mortality (HR 2.35, 95% CI 1.41-3.42) but not CVD mortality (HR 1.08, 95% CI 0.60-1.94). The associations were replicated among UKB participants (aged 66.9±1.5 years), including 8739 deaths over a mean follow-up of 12.7±0.8 years. There was a non-linear association between HDL-C levels and all-cause and cause-specific mortality. The association between HDL-C levels and mortality was unrelated to variations in the HDL-C polygenic score. No significant association was found between HDL-C levels and mortality in women. Higher HDL-C levels are associated with increased risk from cancer and "non-cancer non-CVD" mortality in healthy older men but no such relationship was observed in women.

Corinthian Currants Promote the Expression of Paraoxonase-1 and Enhance the Antioxidant Status in Serum and Brain of 5xFAD Mouse Model of Alzheimer's Disease

Paraoxonase-1 (PON1), a serum antioxidant enzyme, has been implicated in Alzheimer's disease (AD) pathogenesis that involves early oxidative damage. Corinthian currants and their components have been shown to display antioxidant and other neuroprotective effects in AD. We evaluated the effect of a Corinthian currant paste-supplemented diet (CurD), provided to 1-month-old 5xFAD mice for 1, 3, and 6 months, on PON1 activity and levels of oxidation markers in serum and the brain of mice as compared to a control diet (ConD) or glucose/fructose-matched diet (GFD). Administration of CurD for 1 month increased PON1 activity and decreased oxidized lipid levels in serum compared to ConD and GFD. Longer-term administration of CurD did not, however, affect serum PON1 activity and oxidized lipid levels. Furthermore, CurD administered for 1 and 3 months, but not for 6 months, increased PON1 activity and decreased free radical levels in the cortex of mice compared to ConD and GFD. To probe the mechanism for the increased PON1 activity in mice, we studied the effect of Corinthian currant polar phenolic extract on PON1 activity secreted by Huh-7 hepatocytes or HEK293 cells transfected with a PON1-expressing plasmid. Incubation of cells with the extract led to a dose-dependent increase of secreted PON1 activity, which was attributed to increased cellular PON1 expression. Collectively, our findings suggest that phenolics in Corinthian currants can increase the hepatic expression and activity of antioxidant enzyme PON1 and that a Corinthian currant-supplemented diet during the early stages of AD in mice reduces brain oxidative stress.

Zinc finger protein ZNF638 regulates triglyceride metabolism via ANGPTL8 in an estrogen dependent manner

BACKGROUND AND AIM

Triglyceride (TG) levels are closely related to obesity, fatty liver and cardiovascular diseases, while the regulatory factors and mechanism for triglyceride homeostasis are still largely unknown. Zinc Finger Protein 638 (ZNF638) is a newly discovered member of zinc finger protein family for adipocyte function in vitro. The aim of the present work was to investigate the role of ZNF638 in regulating triglyceride metabolism in mice.

METHODS

We generated ZNF638 adipose tissue specific knockout mice (ZNF638 FKO) by cross-breeding ZNF638 flox to Adiponectin-Cre mice and achieved adipose tissue ZNF638 overexpression via adenoviral mediated ZNF638 delivery in inguinal adipose tissue (iWAT) to examined the role and mechanisms of ZNF638 in fat biology and whole-body TG homeostasis.

RESULTS

Although ZNF638 FKO mice showed similar body weights, body composition, glucose metabolism and serum parameters compared to wild-type mice under chow diet, serum TG levels in ZNF638 FKO mice were increased dramatically after refeeding compared to wild-type mice, accompanied with decreased endothelial lipoprotein lipase (LPL) activity and increased lipid absorption of the small intestine. Conversely, ZNF638 overexpression in iWAT reduced serum TG levels while enhanced LPL activity after refeeding in female C57BL/6J mice and obese ob/ob mice. Specifically, only female mice exhibited altered TG metabolism upon ZNF638 expression changes in fat. Mechanistically, RNA-sequencing analysis revealed that the TG regulator angiopoietin-like protein 8 (Angptl8) was highly expressed in iWAT of female ZNF638 FKO mice. Neutralizing circulating ANGPTL8 in female ZNF638 FKO mice abolished refeeding-induced TG elevation. Furthermore, we demonstrated that ZNF638 functions as a transcriptional repressor by recruiting HDAC1 for histone deacetylation and broad lipid metabolic gene suppression, including Angptl8 transcription inhibition. Moreover, we showed that the sexual dimorphism is possibly due to estrogen dependent regulation on ZNF638-ANGPTL8 axis.

CONCLUSION

We revealed a role of ZNF638 in the regulation of triglyceride metabolism by affecting Angptl8 transcriptional level in adipose tissue with sexual dimorphism.

The role of gonadal hormones and sex chromosomes in sex-dependent effects of early nutrition on metabolic health

Early-life conditions such as prenatal nutrition can have long-term effects on metabolic health, and these effects may differ between males and females. Understanding the biological mechanisms underlying sex differences in the response to early-life environment will improve interventions, but few such mechanisms have been identified, and there is no overall framework for understanding sex differences. Biological sex differences may be due to chromosomal sex, gonadal sex, or interactions between the two. This review describes approaches to distinguish between the roles of chromosomal and gonadal sex, and summarizes findings regarding sex differences in metabolism. The Four Core Genotypes (FCG) mouse model allows dissociation of the sex chromosome genotype from gonadal type, whereas the XY* mouse model can be used to distinguish effects of X chromosome dosage vs the presence of the Y chromosome. Gonadectomy can be used to distinguish between organizational (permanent) and activational (reversible) effects of sex hormones. Baseline sex differences in a variety of metabolic traits are influenced by both activational and organizational effects of gonadal hormones, as well as sex chromosome complement. Thus far, these approaches have not been widely applied to examine sex-dependent effects of prenatal conditions, although a number of studies have found activational effects of estradiol to be protective against the development of hypertension following early-life adversity. Genes that escape X chromosome inactivation (XCI), such as Kdm5c, contribute to baseline sex-differences in metabolism, while Ogt, another XCI escapee, leads to sex-dependent responses to prenatal maternal stress. Genome-wide approaches to the study of sex differences include mapping genetic loci influencing metabolic traits in a sex-dependent manner. Seeking enrichment for binding sites of hormone receptors among genes showing sexually-dimorphic expression can elucidate the relative roles of hormones. Using the approaches described herein to identify mechanisms underlying sex-dependent effects of early nutrition on metabolic health may enable the identification of fundamental mechanisms and potential interventions.

Gonadal sex vs genetic sex in experimental atherosclerosis

Epidemiological data and interventional studies with hormone replacement therapy suggest that women, at least until menopause, are at decreased cardiovascular risk compared to men. Still the molecular mechanisms beyond this difference are debated and the investigation in experimental models of atherosclerosis has been pivotal to prove that the activation of the estrogen receptor is atheroprotective, despite not enough to explain the differences reported in cardiovascular disease between male and female. This casts also for investigating the importance of the sex chromosome complement (genetic sex) beyond the contribution of sex hormones (gonadal sex) on atherosclerosis. Aim of this review is to present the dualism between gonadal sex and genetic sex with a focus on the data available from experimental models. The molecular mechanisms driving changes in lipid metabolism, immuno-inflammatory reactivity and vascular response in males and females that affect atherosclerosis progression will be discussed.

A physiologically based model of bile acid metabolism in mice

Bile acid (BA) metabolism is a complex system that includes a wide variety of primary and secondary, as well as conjugated and unconjugated BAs that undergo continuous enterohepatic circulation (EHC). Alterations in both composition and dynamics of BAs have been associated with various diseases. However, a mechanistic understanding of the relationship between altered BA metabolism and related diseases is lacking. Computational modeling may support functional analyses of the physiological processes involved in the EHC of BAs along the gut-liver axis. In this study, we developed a physiologically based model of murine BA metabolism describing synthesis, hepatic and microbial transformations, systemic distribution, excretion, and EHC of BAs at the whole-body level. For model development, BA metabolism of specific pathogen-free (SPF) mice was characterized in vivo by measuring BA levels and composition in various organs, expression of transporters along the gut, and cecal microbiota composition. We found significantly different BA levels between male and female mice that could only be explained by adjusted expression of the hepatic enzymes and transporters in the model. Of note, this finding was in agreement with experimental observations. The model for SPF mice could also describe equivalent experimental data in germ-free mice by specifically switching off microbial activity in the intestine. The here presented model can therefore facilitate and guide functional analyses of BA metabolism in mice, e.g., the effect of pathophysiological alterations on BA metabolism and translation of results from mouse studies to a clinically relevant context through cross-species extrapolation.

Immune-Related Genes in the Pathogenesis of Atherosclerosis: Based on Sex Differences

Purpose

Atherosclerosis is still a global public problem with increasing incidence rate and mortality. It has been found that gender factors play an important role in the progression of atherosclerosis. However, few people explore gender related atherosclerosis at the level of genes and immune cells. The purpose of this study was to determine genetic and immune cell differences between male and female samples.

Patients and Methods

This study aims to identify differential genes between male and female samples in the GSE43292 dataset. The focus will be on identifying immune-related genes (IRGs) among these differentially expressed genes. Subsequently, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis will be employed to explore the enrichment of IRGs in biological processes, molecular functions, cellular components, and pathways. Furthermore, a protein-protein interaction (PPI) network for the IRGs will be constructed using Cytoscape software. To estimate the degree of immune cell infiltration, single-sample gene set enrichment analysis (ssGSEA) will be conducted. Moreover, the identified IRGs will be validated using GSE28829 dataset. Finally, we validated in atherosclerotic mice.

Results

Seven IRGs (CCL13, IL1RN, FPR2, S100A8, CCL19, CXCL1, CXCL8) were identified as being overexpressed in male atherosclerosis. GO and KEGG analysis revealed that these IRGs are primarily enriched in inflammatory response pathways, cytokine signaling pathways, and cytokine- cytokine receptor interactions. Notably, when compared to females, there was a significant infiltration of immune cells in male specimens. Importantly, all seven IRGs demonstrated high diagnostic value in GSE28829 dataset. The use of animal samples supports our results.

Conclusion

This study demonstrates the effectiveness of seven IRGs and reveal sex differences in atherosclerosis. Notably, there is a significant presence of immune cells within the atherosclerotic plaque of men compared to women. These findings have potential implications for the development of personalized treatment approaches targeting gender-related atherosclerosis.

The impact of chromosomal sex on cardiometabolic health and disease

Many aspects of metabolism are sex-biased, from gene expression in metabolic tissues to the prevalence and presentation of cardiometabolic diseases. The influence of hormones produced by male and female gonads has been widely documented, but recent studies have begun to elucidate the impact of genetic sex (XX or XY chromosomes) on cellular and organismal metabolism. XX and XY cells have differential gene dosage conferred by specific genes that escape X chromosome inactivation or the presence of Y chromosome genes that are absent from XX cells. Studies in mouse models that dissociate chromosomal and gonadal sex have uncovered mechanisms for sex-biased epigenetic, transcriptional, and post-transcriptional regulation of gene expression in conditions such as obesity, atherosclerosis, pulmonary hypertension, autoimmune disease, and Alzheimer's disease.

Transcriptome and secretome profiling of sensory neurons reveals sex differences in pathways relevant to insulin sensing and insulin secretion

Sensory neurons in the dorsal root ganglia (DRG) convey somatosensory and metabolic cues to the central nervous system and release substances from stimulated terminal endings in peripheral organs. Sex-biased variations driven by the sex chromosome complement (XX and XY) have been implicated in the sensory-islet crosstalk. However, the molecular underpinnings of these male-female differences are not known. Here, we aim to characterize the molecular repertoire and the secretome profile of the lower thoracic spinal sensory neurons and to identify molecules with sex-biased insulin sensing- and/or insulin secretion-modulating activity that are encoded independently of circulating gonadal sex hormones. We used transcriptomics and proteomics to uncover differentially expressed genes and secreted molecules in lower thoracic T5-12 DRG sensory neurons derived from sexually immature 3-week-old male and female C57BL/6J mice. Comparative transcriptome and proteome analyses revealed differential gene expression and protein secretion in DRG neurons in males and females. The transcriptome analysis identified, among others, higher insulin signaling/sensing capabilities in female DRG neurons; secretome screening uncovered several sex-specific candidate molecules with potential regulatory functions in pancreatic β cells. Together, these data suggest a putative role of sensory interoception of insulin in the DRG-islet crosstalk with implications in sensory feedback loops in the regulation of β-cell activity in a sex-biased manner. Finally, we provide a valuable resource of molecular and secretory targets that can be leveraged for understanding insulin interoception and insulin secretion and inform the development of novel studies/approaches to fathom the role of the sensory-islet axis in the regulation of energy balance in males and females.

Plasma Fatty Acid Biomarkers of Dairy Consumption Are Associated with Sex-Dependent Effects on Metabolic Syndrome Components in Mexican Adolescents

INTRODUCTION

During adolescence, dairy product intake has shown conflicting associations with metabolic syndrome (MetS) components, which are risk factors for cardiovascular disease (CVD). This study aims to investigate the association between plasma fatty acids (FAs) C15:0, C17:0, and t-C16:1n-7, as biomarkers of dairy intake, with MetS and its components in Mexican adolescents.

METHODS

A sample of 311 participants from the Early Life Exposure in Mexico City to Environmental Toxicants (ELEMENT) cohort was included in this cross-sectional analysis. FA concentrations were measured in plasma as a percentage of total FA. We used quantile regression models stratified by sex to evaluate the association between FA quantiles and MetS components, adjusting for age, socioeconomic status (SES), sedentary behavior, BMI z-score, pubertal status, and energy intake.

RESULTS

We found significant associations between dairy biomarkers and the median of MetS variables. In females, t-C16:1n-7 was associated with a decrease of 2.97 cm in WC (Q4 vs. Q1; 95% CI: -5.79, -0.16). In males, C15:0 was associated with an increase of 5.84 mm/Hg in SBP (Q4 vs. Q1; CI: 1.82, 9.85). For HDL-C, we observed opposite associations by sex. C15:0 in males was associated with decreased HDL-C (Q3 vs. Q1: β = -4.23; 95% CI: -7.98, -0.48), while in females, C15:0 and t-C16:1n-7 were associated with increased HDL-C (Q3 vs. Q1: β = 4.75; 95% CI: 0.68, 8.82 and Q4 vs. Q1: β = 6.54; 95% CI: 2.01, 11.07), respectively. Additionally, in both sexes, different levels of C15:0, C17:0, and t-C16:1n-7 were associated with increased triglycerides (TG).

CONCLUSION

Our results suggest that adolescent dairy intake may be associated in different directions with MetS components and that associations are sex-dependent.

Sex Chromosome Complement and Estradiol Modify Cocaine Self-Administration Behaviors in Male Mice

INTRODUCTION

Women are more vulnerable to cocaine's reinforcing effects and have a more rapid course to addiction after initial cocaine use as compared to men. Studies in rodents similarly indicate an enhanced sensitivity to the reinforcing effects of cocaine in females versus males. Levels of estradiol (E2) are correlated with vulnerability to the rewarding actions of cocaine. Here, we asked if sex chromosome complement (SCC) influences vulnerability to cocaine use.

METHODS

We used the four-core genotype mouse that produces gonadal males and females with either XX or XY SCC. Mice were gonadectomized and implanted with either an estradiol (E2) or cholesterol-filled pellet. This allowed us to determine the effects of SCC in the absence (cholesterol-treated) and presence of tonic high physiological hormone levels (estradiol). Acquisition of cocaine self-administration was determined over a 12-day period using an escalated dose procedure (0.3 mg/kg/infusion, sessions 1-6; 0.6 mg/kg/infusion, sessions 6-12).

RESULTS

Without estradiol treatment, a greater percentage of castrated XY mice acquired cocaine self-administration and did so at a faster rate than XX castrates and ovariectomized XY females. These same XY males acquired sooner, infused more cocaine, and directed more nose pokes to the rewarded nose-poke hole than XX castrates and XY males receiving E2.

CONCLUSION

Our results suggest that in gonadal male mice, SCC and estradiol can modulate the reinforcing effects of cocaine which may influence the likelihood of cocaine use.

Effects of steroid hormones on lipid metabolism in sexual dimorphism: A Mendelian randomization study

BACKGROUND

Although the role of steroid hormones in lipid levels has been partly discussed in the context of separate sexes, the causal relationship between steroid hormones and lipid metabolism according to sex has not been elucidated because of the limitations of observational studies. We assessed the relationship between steroid hormones and lipid metabolism in separate sexes using a two-sample Mendelian randomization (MR) study.

METHODS

Instrumental variables for dehydroepiandrosterone sulfate (DHEAS), progesterone, estradiol, and androstenedione were selected. MR analysis was performed using inverse-variance weighted, MR-Egger, weighted median, and MR pleiotropy residual sum and outlier tests. Cochran's Q test, the MR-Egger intercept test, and leave-one-out analysis were used for sensitivity analyses.

RESULTS

The results showed that the three steroid hormones affected lipid metabolism and exhibited sex differences. In males, DHEAS was negatively correlated with total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and apolipoprotein B (P = 0.007; P = 0.006; P = 0.041, respectively), and progesterone was negatively correlated with TC and LDL-C (P = 0.019; P = 0.038, respectively). In females, DHEAS was negatively correlated with TC (P = 0.026) and androstenedione was negatively correlated with triglycerides and apolipoprotein A (P = 0.022; P = 0.009, respectively). No statistically significant association was observed between the estradiol levels and lipid metabolism in male or female participants.

CONCLUSIONS

Our findings identified sex-specific causal networks between steroid hormones and lipid metabolism. Steroid hormones, including DHEAS, progesterone, and androstenedione, exhibited beneficial effects on lipid metabolism in both sexes; however, the specific lipid profiles affected by steroid hormones differed between the sexes.

Rosa26-LSL-dCas9-VPR: a versatile mouse model for tissue specific and simultaneous activation of multiple genes for drug discovery

Transgenic animals with increased or abrogated target gene expression are powerful tools for drug discovery research. Here, we developed a CRISPR-based Rosa26-LSL-dCas9-VPR mouse model for targeted induction of endogenous gene expression using different Adeno-associated virus (AAV) capsid variants for tissue-specific gRNAs delivery. To show applicability of the model, we targeted low-density lipoprotein receptor (LDLR) and proprotein convertase subtilisin/kexin type 9 (PCSK9), either individually or together. We induced up to ninefold higher expression of hepatocellular proteins. In consequence of LDLR upregulation, plasma LDL levels almost abolished, whereas upregulation of PCSK9 led to increased plasma LDL and cholesterol levels. Strikingly, simultaneous upregulation of both LDLR and PCSK9 resulted in almost unaltered LDL levels. Additionally, we used our model to achieve expression of all α₁-Antitrypsin (AAT) gene paralogues simultaneously. These results show the potential of our model as a versatile tool for optimized targeted gene expression, alone or in combination.

Chromosomal and gonadal sex drive sex differences in lipids and hepatic gene expression in response to hypercholesterolemia and statin treatment

BACKGROUND

Biological sex impacts susceptibility and presentation of cardiovascular disease, which remains the leading cause of death for both sexes. To reduce cardiovascular disease risk, statin drugs are commonly prescribed to reduce circulating cholesterol levels through inhibition of cholesterol synthesis. The effectiveness of statin therapy differs between individuals with a sex bias in the frequency of adverse effects. Limited information is available regarding the mechanisms driving sex-specific responses to hypercholesterolemia or statin treatment.

METHODS

Four Core Genotypes mice (XX and XY mice with ovaries and XX and XY mice with testes) on a hypercholesteremic Apoe-/- background were fed a chow diet without or with simvastatin for 8 weeks. Plasma lipid levels were quantified and hepatic differential gene expression was evaluated with RNA-sequencing to identify the independent effects of gonadal and chromosomal sex.

RESULTS

In a hypercholesterolemic state, gonadal sex influenced the expression levels of more than 3000 genes, and chromosomal sex impacted expression of nearly 1400 genes, which were distributed across all autosomes as well as the sex chromosomes. Gonadal sex uniquely influenced the expression of ER stress response genes, whereas chromosomal and gonadal sex influenced fatty acid metabolism gene expression in hypercholesterolemic mice. Sex-specific effects on gene regulation in response to statin treatment included a compensatory upregulation of cholesterol biosynthetic gene expression in mice with XY chromosome complement, regardless of presence of ovaries or testes.

CONCLUSION

Gonadal and chromosomal sex have independent effects on the hepatic transcriptome to influence different cellular pathways in a hypercholesterolemic environment. Furthermore, chromosomal sex in particular impacted the cellular response to statin treatment. An improved understanding of how gonadal and chromosomal sex influence cellular response to disease conditions and in response to drug treatment is critical to optimize disease management for all individuals.

X chromosome agents of sexual differentiation

Understanding sex differences in physiology and disease requires the identification of the molecular agents that cause phenotypic sex differences. Two groups of such agents are genes located on the sex chromosomes, and gonadal hormones. The former have coherent linkage to chromosomes that form differently in the two sexes under the influence of genomic forces that are not related to reproductive function, whereas the latter have a direct or indirect relationship to reproduction. Evidence published in the past 5 years supports the identification of several agents of sexual differentiation encoded by the X chromosome in mice, including Kdm5c, Kdm6a, Ogt and Xist. These X chromosome agents have wide pleiotropic effects, potentially influencing sex differences in many different tissues, a characteristic shared with the gonadal hormones. The identification of X chromosome agents of sexual differentiation will facilitate understanding of complex intersecting gene pathways underlying sex differences in disease.

Sex as a Biological Variable in Nutrition Research: From Human Studies to Animal Models

Biological sex is a fundamental source of phenotypic variability across species. Males and females have different nutritional needs and exhibit differences in nutrient digestion and utilization, leading to different health outcomes throughout life. With personalized nutrition gaining popularity in scientific research and clinical practice, it is important to understand the fundamentals of sex differences in nutrition research. Here, we review key studies that investigate sex dimorphism in nutrition research: sex differences in nutrient intake and metabolism, sex-dimorphic response in nutrient-restricted conditions, and sex differences in diet and gut microbiome interactions. Within each area above, factors from sex chromosomes, sex hormones, and sex-specific loci are highlighted.

Illuminating the Mechanisms Underlying Sex Differences in Cardiovascular Disease

Sex is a key risk factor for many types of cardiovascular disease. It is imperative to understand the mechanisms underlying sex differences to devise optimal preventive and therapeutic approaches for all individuals. Both biological sex (determined by sex chromosomes and gonadal hormones) and gender (social and cultural behaviors associated with femininity or masculinity) influence differences between men and women in disease susceptibility and pathology. Here, we focus on the application of experimental mouse models that elucidate the influence of 2 components of biological sex-sex chromosome complement (XX or XY) and gonad type (ovaries or testes). These models have revealed that in addition to well-known effects of gonadal hormones, sex chromosome complement influences cardiovascular risk factors, such as plasma cholesterol levels and adiposity, as well as the development of atherosclerosis and pulmonary hypertension. One mechanism by which sex chromosome dosage influences cardiometabolic traits is through sex-biased expression of X chromosome genes that escape X inactivation. These include chromatin-modifying enzymes that regulate gene expression throughout the genome. The identification of factors that determine sex-biased gene expression and cardiometabolic traits will expand our mechanistic understanding of cardiovascular disease processes and provide insight into sex differences that remain throughout the lifespan as gonadal hormone levels alter with age.

Integrating Sex Chromosome and Endocrine Theories to Improve Teaching of Sexual Differentiation

Major sex differences in mammalian tissues are functionally tied to reproduction and evolved as adaptations to meet different reproductive needs of females and males. They were thus directly controlled by gonadal hormones. Factors encoded on the sex chromosomes also cause many sex differences in diverse tissues because they are present in different doses in XX and XY cells. The sex chromosome effects likely evolved not because of demands of reproduction, but as side effects of genomic forces that adaptively reduced sexual inequality. Sex-specific effects of particular factors, including gonadal hormones, therefore, are not necessarily explained as adaptations for reproduction, but also as potential factors offsetting, rather than producing, sex differences. The incorporation of these concepts would improve future teaching about sexual differentiation.

Relative contributions of sex hormones, sex chromosomes, and gonads to sex differences in tissue gene regulation

Sex differences in physiology and disease in mammals result from the effects of three classes of factors that are inherently unequal in males and females: reversible (activational) effects of gonadal hormones, permanent (organizational) effects of gonadal hormones, and cell-autonomous effects of sex chromosomes, as well as genes driven by these classes of factors. Often, these factors act together to cause sex differences in specific phenotypes, but the relative contribution of each and the interactions among them remain unclear. Here, we used the four core genotypes (FCG) mouse model with or without hormone replacement to distinguish the effects of each class of sex-biasing factors on transcriptome regulation in liver and adipose tissues. We found that the activational hormone levels have the strongest influence on gene expression, followed by the organizational gonadal sex effect, and last, sex chromosomal effect, along with interactions among the three factors. Tissue specificity was prominent, with a major impact of estradiol on adipose tissue gene regulation and of testosterone on the liver transcriptome. The networks affected by the three sex-biasing factors include development, immunity and metabolism, and tissue-specific regulators were identified for these networks. Furthermore, the genes affected by individual sex-biasing factors and interactions among factors are associated with human disease traits such as coronary artery disease, diabetes, and inflammatory bowel disease. Our study offers a tissue-specific account of the individual and interactive contributions of major sex-biasing factors to gene regulation that have broad impact on systemic metabolic, endocrine, and immune functions.

Mechanisms and implications of sex differences in cardiac aging

Aging promotes structural and functional remodeling of the heart, even in the absence of external factors. There is growing clinical and experimental evidence supporting the existence of sex-specific patterns of cardiac aging, and in some cases, these sex differences emerge early in life. Despite efforts to identify sex-specific differences in cardiac aging, understanding how these differences are established and regulated remains limited. In addition to contributing to sex differences in age-related heart disease, sex differences also appear to underlie differential responses to cardiac stress such as adrenergic activation. Identifying the underlying mechanisms of sex-specific differences may facilitate the characterization of underlying heart disease phenotypes, with the ultimate goal of utilizing sex-specific therapeutic approaches for cardiac disease. The purpose of this review is to discuss the mechanisms and implications of sex-specific cardiac aging, how these changes render the heart more susceptible to disease, and how we can target age- and sex-specific differences to advance therapies for both male and female patients.

Importance of sex and gender in ischaemic stroke and carotid atherosclerotic disease

Stroke is a leading cause of death and disability worldwide. Women are disproportionately affected by stroke, exhibiting higher mortality and disability rates post-stroke than men. Clinical stroke research has historically included mostly men and studies were not properly designed to perform sex- and gender-based analyses, leading to under-appreciation of differences between men and women in stroke presentation, outcomes, and response to treatment. Reasons for these differences are likely multifactorial; some are due to gender-related factors (i.e. decreased social support, lack of stroke awareness), yet others result from biological differences between sexes. Unlike men, women often present with 'atypical' stroke symptoms. Lack of awareness of 'atypical' presentation has led to delays in hospital arrival, diagnosis, and treatment of women. Differences also extend to carotid atherosclerotic disease, a cause of stroke, where plaques isolated from women are undeniably different in morphology/composition compared to men. As a result, women may require different treatment than men, as evidenced by the fact that they derive less benefit from carotid revascularization than men but more benefit from medical management. Despite this, women are less likely than men to receive medical therapy for cardiovascular risk factor management. This review focuses on the importance of sex and gender in ischaemic stroke and carotid atherosclerotic disease, summarizing the current evidence with respect to (i) stroke incidence, mortality, awareness, and outcomes, (ii) carotid plaque prevalence, morphology and composition, and gene connectivity, (iii) the role of sex hormones and sex chromosomes in atherosclerosis and ischaemic stroke risk, and (iv) carotid disease management.

Sexual dimorphism in placental development and its contribution to health and diseases

According to the Developmental Origin of Health and Disease (DOHaD), intrauterine exposure to adverse environments can affect fetus and birth outcomes and lead to long-term disease susceptibility. Evidence has shown that neonatal outcomes and the timing and severity of adult diseases are sexually dimorphic. As the link between mother and fetus, the placenta is an essential regulator of fetal development programming. It is found that the physiological development trajectory of the placenta has sexual dimorphism. Furthermore, under pathological conditions, the placental function undergoes sex-specific adaptation to ensure fetal survival. Therefore, the placenta may be an important mediator of sexual dimorphism in neonatal outcomes and adult disease susceptibility. Few systematic reviews have been conducted on sexual dimorphism in placental development and its underlying mechanisms. In this review, sex chromosomes and sex hormones, as the main reasons for sexual differentiation of the placenta, will be discussed. Besides, in the etiology of fetal-originated adult diseases, overexposure to glucocorticoids is closely related to adverse neonatal outcomes and long-term disease susceptibility. Studies have found that prenatal glucocorticoid overexposure leads to sexually dimorphic expression of placental glucocorticoid receptor isoforms, resulting in different sensitivity of the placenta to glucocorticoids, and may further affect fetal development. The present review examines what is currently known about sex differences in placental development and the underlying regulatory mechanisms of this sex bias. This review highlights the importance of placental contributions to the origins of sexual dimorphism in health and diseases. It may help develop personalized diagnosis and treatment strategies for fetal development in pathological pregnancies.

Elongated PEO-based nanoparticles bind the high-density lipoprotein (HDL) receptor scavenger receptor class B I (SR-BI)

Targeting cell-surface receptors with nanoparticles (NPs) is a crucial aspect of nanomedicine. Here, we show that soft, flexible, elongated NPs with poly-ethylene-oxide (PEO) exteriors and poly-butadiene (PBD) interiors - PEO-PBD filomicelles - interact directly with the major high-density lipoprotein (HDL) receptor and SARS-CoV-2 uptake factor, SR-BI. Filomicelles have a ~ 6-fold stronger interaction with reconstituted SR-BI than PEO-PBD spheres. HDL, and the lipid transport inhibitor, BLT-1, both block the uptake of filomicelles by macrophages and Idla7 cells, the latter are constitutively expressing SR-BI (Idla7-SR-BI). Co-injections of HDL and filomicelles into wild-type mice reduced filomicelle signal in the liver and increased filomicelle plasma levels. The same was true with SCARB1^-/- mice. SR-BI binding is followed by phagocytosis for filomicelle macrophage entry, but only SR-BI is needed for entry into Idla7-SR-BI cells. PEO-PBD spheres did not interact strongly with SR-BI in the above experiments. The results show elongated PEO-based NPs can bind cells via cooperativity among SR-BI receptors on cell surfaces.

Sex differences in the intestinal microbiome: interactions with risk factors for atherosclerosis and cardiovascular disease

Background

There are clearly sex differences in cardiovascular disease. On average, women experience cardiovascular events at an older age, and at any age, women, on average, have less atherosclerotic plaque than men. The role of the human intestinal microbiome in health and disease has garnered significant interest in recent years, and there have been indications of sex differences in the intestinal microbiome. The purpose of this narrative review was to evaluate evidence of sex differences in the interaction between the intestinal microbiome and risk factors for cardiovascular disease. Several studies have demonstrated changes in microbiota composition and metabolic profile as a function of diet, sex hormones, and host metabolism, among other factors. This dysbiosis has consequently been associated with several disease states, including atherosclerosis and cardiovascular disease. In this respect, there is a growing appreciation for the microbiota and its secreted metabolites, including trimethylamine N-oxide (TMAO), derived from intestinal bacterial metabolic pathways involving dietary choline and l-carnitine, as novel risk factors for atherosclerosis and cardiovascular outcomes. Although traditional risk factors for vascular disease have been studied broadly over the years, there exists little research to evaluate interactions of cardiovascular risk factors with a potentially sexually dimorphic intestinal microbiome. This review evaluates the role of sex differences in the composition of the intestinal microbiome, including effects of sex hormones on the microbiome, and the effects of these sex differences on cardiovascular risk factors. Diabetes and obesity exhibit sexual dimorphism, while the data concerning hypertension and dyslipidemia remain inconclusive based on the available literature. In addition, an increased proportion of gram-negative species capable of driving metabolic endotoxemia and a low-grade inflammatory response, as well as decreased numbers of butyrate-producing species, have been observed in relation to traditional vascular risk factors. In this context, circulating SCFAs and TMAO are recognized as key metabolites of the intestinal microbiome that can be readily measured in the blood for the evaluation of metabolic profile.

Conclusion

Novel strategies focused on resolving intestinal dysbiosis as a means to slow progression of atherosclerosis and reduce the risk of cardiovascular disease should be evaluated through a lens of sex differences.

Chromosome Xq23 is associated with lower atherogenic lipid concentrations and favorable cardiometabolic indices

Autosomal genetic analyses of blood lipids have yielded key insights for coronary heart disease (CHD). However, X chromosome genetic variation is understudied for blood lipids in large sample sizes. We now analyze genetic and blood lipid data in a high-coverage whole X chromosome sequencing study of 65,322 multi-ancestry participants and perform replication among 456,893 European participants. Common alleles on chromosome Xq23 are strongly associated with reduced total cholesterol, LDL cholesterol, and triglycerides (min P = 8.5 × 10-72), with similar effects for males and females. Chromosome Xq23 lipid-lowering alleles are associated with reduced odds for CHD among 42,545 cases and 591,247 controls (P = 1.7 × 10-4), and reduced odds for diabetes mellitus type 2 among 54,095 cases and 573,885 controls (P = 1.4 × 10-5). Although we observe an association with increased BMI, waist-to-hip ratio adjusted for BMI is reduced, bioimpedance analyses indicate increased gluteofemoral fat, and abdominal MRI analyses indicate reduced visceral adiposity. Co-localization analyses strongly correlate increased CHRDL1 gene expression, particularly in adipose tissue, with reduced concentrations of blood lipids.

Analysis of sex differences in dietary copper-fructose interaction-induced alterations of gut microbial activity in relation to hepatic steatosis

BACKGROUND

Inadequate copper intake and increased fructose consumption represent two important nutritional problems in the USA. Dietary copper-fructose interactions alter gut microbial activity and contribute to the development of nonalcoholic fatty liver disease (NAFLD). The aim of this study is to determine whether dietary copper-fructose interactions alter gut microbial activity in a sex-differential manner and whether sex differences in gut microbial activity are associated with sex differences in hepatic steatosis.

METHODS

Male and female weanling Sprague-Dawley (SD) rats were fed ad libitum with an AIN-93G purified rodent diet with defined copper content for 8 weeks. The copper content is 6 mg/kg and 1.5 mg/kg in adequate copper diet (CuA) and marginal copper diet (CuM), respectively. Animals had free access to either deionized water or deionized water containing 10% fructose (F) (w/v) as the only drink during the experiment. Body weight, calorie intake, plasma alanine aminotransferase, aspartate aminotransferase, and liver histology as well as liver triglyceride were evaluated. Fecal microbial contents were analyzed by 16S ribosomal RNA (16S rRNA) sequencing. Fecal and cecal short-chain fatty acids (SCFAs) were determined by gas chromatography-mass spectrometry (GC-MS).

RESULTS

Male and female rats exhibit similar trends of changes in the body weight gain and calorie intake in response to dietary copper and fructose, with a generally higher level in male rats. Several female rats in the CuAF group developed mild steatosis, while no obvious steatosis was observed in male rats fed with CuAF or CuMF diets. Fecal 16S rRNA sequencing analysis revealed distinct alterations of the gut microbiome in male and female rats. Linear discriminant analysis (LDA) effect size (LEfSe) identified sex-specific abundant taxa in different groups. Further, total SCFAs, as well as, butyrate were decreased in a more pronounced manner in female CuMF rats than in male rats. Of note, the decreased SCFAs are concomitant with the reduced SCFA producers, but not correlated to hepatic steatosis.

CONCLUSIONS

Our data demonstrated sex differences in the alterations of gut microbial abundance, activities, and hepatic steatosis in response to dietary copper-fructose interaction in rats. The correlation between sex differences in metabolic phenotypes and alterations of gut microbial activities remains elusive.

Four Core Genotypes and XY* mouse models: Update on impact on SABV research

The impact of two mouse models is reviewed, the Four Core Genotypes and XY* models. The models are useful for determining if the causes of sex differences in phenotypes are either hormonal or sex chromosomal, or both. Used together, the models also can distinguish between the effects of X or Y chromosome genes that contribute to sex differences in phenotypes. To date, the models have been used to uncover sex chromosome contributions to sex differences in a wide variety of phenotypes, including brain and behavior, autoimmunity and immunity, cardiovascular disease, metabolism, and Alzheimer's Disease. In some cases, use of the models has been a strategy leading to discovery of specific X or Y genes that protect from or exacerbate disease. Sex chromosome and hormonal factors interact, in some cases to reduce the effects of each other. Future progress will come from more extensive application of these models, and development of similar models in other species.

X chromosome dosage of histone demethylase KDM5C determines sex differences in adiposity

Males and females differ in body composition and fat distribution. Using a mouse model that segregates gonadal sex (ovaries and testes) from chromosomal sex (XX and XY), we showed that XX chromosome complement in combination with a high-fat diet led to enhanced weight gain in the presence of male or female gonads. We identified the genomic dosage of Kdm5c, an X chromosome gene that escapes X chromosome inactivation, as a determinant of the X chromosome effect on adiposity. Modulating Kdm5c gene dosage in XX female mice to levels that are normally present in males resulted in reduced body weight, fat content, and food intake to a degree similar to that seen with altering the entire X chromosome dosage. In cultured preadipocytes, the levels of KDM5C histone demethylase influenced chromatin accessibility (ATAC-Seq), gene expression (RNA-Seq), and adipocyte differentiation. Both in vitro and in vivo, Kdm5c dosage influenced gene expression involved in extracellular matrix remodeling, which is critical for adipocyte differentiation and adipose tissue expansion. In humans, adipose tissue KDM5C mRNA levels and KDM5C genetic variants were associated with body mass. These studies demonstrate that the sex-dependent dosage of Kdm5c contributes to male/female differences in adipocyte biology and highlight X-escape genes as a critical component of female physiology.

Sex differences in stroke co-morbidities

Males and females possess distinct biological differences that manifest in diverse risk profiles for acute and chronic diseases. A well-documented example of this is ischemic stroke. It has been demonstrated that older females have greater prevalence of, and worse outcome after, ischemic stroke than do males and younger females. Loss of estrogen after menopause is heavily implicated as a contributing factor for this phenomenon; however, there is mounting evidence to suggest that certain risk factors tend to occur more often in older females, such as hypertension and atrial fibrillation, while others more adversely affect females than they do males, such as diabetes and smoking. Sex-specific risk factors, such as oral contraceptive use and menopause, could also contribute to the discrepancy in stroke prevalence and outcome. Additionally, there is evidence to suggest that females tend to present with more nontraditional symptoms of acute stroke than do males, making it more difficult for clinicians to correctly identify the occurrence of a stroke, which may delay the administration of thrombolytic intervention. Finally, certain sociodemographic factors, such as the fact that females were more likely to live alone prior to stroke, may contribute to poorer recovery in females. This review will explore the various co-morbidities and sociodemographic factors that contribute to the greater prevalence of and poorer outcome after stroke in older females and will highlight the critical need for considering sex as a predisposing biological variable in stroke studies.

Sex differences in body composition, metabolism-related hormones, and energy homeostasis during aging in Wistar rats

Aging affects the body composition and balance of energy metabolism. Here, we collected in a single work several physiological parameters to show how aging and sex differences can influence energy homeostasis. Body mass index (BMI), Lee index, glucose tolerance, glycemia, and lipidogram in fasting were measured in male and female Wistar rats at the ages of 2, 6, 9, 12, and 18 months. We also measured the lipid profile, free fatty acids, glycerol, glycemia, leptin, adiponectin, insulin, corticosterone (CORT), prolactin (PRL), thyroid stimulated hormone, and triiodothyronine (T3) in 3- and 18-month-old rats of both sexes, fed ad libitum. Animals were classified as obese beginning at 2 months in males and 6 months in females. Aged male rats showed hyperglycemia and glucose intolerance compared to young males and old females. In the ad libitum condition, the 18-month males presented higher serum levels of triglycerides, total cholesterol, and free fatty acids than females. The 18-month-old females had higher PRL and CORT concentration than males, but insulin and T3 were higher in 18-month-old males than females. Our work demonstrated that aging processes on energy metabolism in rats is sex specific, with a better lipid profile and glucose tolerance in aged females.

β-Carotene Oxygenase 1 Activity Modulates Circulating Cholesterol Concentrations in Mice and Humans

BACKGROUND

Plasma cholesterol is one of the strongest risk factors associated with the development of atherosclerotic cardiovascular disease (ASCVD) and myocardial infarction. Human studies suggest that elevated plasma β-carotene is associated with reductions in circulating cholesterol and the risk of myocardial infarction. The molecular mechanisms underlying these observations are unknown.

OBJECTIVE

The objective of this study was to determine the impact of dietary β-carotene and the activity of β-carotene oxygenase 1 (BCO1), which is the enzyme responsible for the conversion of β-carotene to vitamin A, on circulating cholesterol concentration.

METHODS

In our preclinical study, we compared the effects of a 10-d intervention with a diet containing 50 mg/kg of β-carotene on plasma cholesterol in 5-wk-old male and female C57 Black 6 wild-type and congenic BCO1-deficient mice. In our clinical study, we aimed to determine whether 5 common small nucleotide polymorphisms located in the BCO1 locus affected serum cholesterol concentrations in a population of young Mexican adults from the Universities of San Luis Potosí and Illinois: A Multidisciplinary Investigation on Genetics, Obesity, and Social-Environment (UP AMIGOS) cohort.

RESULTS

Upon β-carotene feeding, Bco1-/- mice accumulated >20-fold greater plasma β-carotene and had ∼30 mg/dL increased circulating total cholesterol (P < 0.01) and non-HDL cholesterol (P < 0.01) than wild-type congenic mice. Our results in the UP AMIGOS cohort show that the rs6564851 allele of BCO1, which has been linked to BCO1 enzymatic activity, was associated with a reduction in 10 mg/dL total cholesterol concentrations (P = 0.009) when adjusted for vitamin A and carotenoid intakes. Non-HDL-cholesterol concentration was also reduced by 10 mg/dL when the data were adjusted for vitamin A and total carotenoid intakes (P = 0.002), or vitamin A and β-carotene intakes (P = 0.002).

CONCLUSIONS

Overall, our results in mice and young adults show that BCO1 activity impacts circulating cholesterol concentration, linking vitamin A formation with the risk of developing ASCVD.

Approaching Sex Differences in Cardiovascular Non-Coding RNA Research

Cardiovascular disease (CVD) is the biggest cause of sickness and mortality worldwide in both males and females. Clinical statistics demonstrate clear sex differences in risk, prevalence, mortality rates, and response to treatment for different entities of CVD. The reason for this remains poorly understood. Non-coding RNAs (ncRNAs) are emerging as key mediators and biomarkers of CVD. Similarly, current knowledge on differential regulation, expression, and pathology-associated function of ncRNAs between sexes is minimal. Here, we provide a state-of-the-art overview of what is known on sex differences in ncRNA research in CVD as well as discussing the contributing biological factors to this sex dimorphism including genetic and epigenetic factors and sex hormone regulation of transcription. We then focus on the experimental models of CVD and their use in translational ncRNA research in the cardiovascular field. In particular, we want to highlight the importance of considering sex of the cellular and pre-clinical models in clinical studies in ncRNA research and to carefully consider the appropriate experimental models most applicable to human patient populations. Moreover, we aim to identify sex-specific targets for treatment and diagnosis for the biggest socioeconomic health problem globally.

EHBP1 SNPs, Their Haplotypes, and Gene-Environment Interactive Effects on Serum Lipid Levels

The associations between single nucleotide polymorphisms (SNPs) rs2710642 and rs10496099 and their effect on the EH domain-binding protein 1 (EHBP1) gene and serum lipid profiles remain uncertain. This study was performed to investigate the two EHBP1 SNPs in Han and Maonan populations, including their association, haplotypes, and effects on serum lipid levels. Two EHBP1 SNPs in 564 Han and 796 Maonan participants were genotyped by high-throughput sequencing, and then the genotype and haplotype distributions of two EHBP1 SNPs were analyzed. Moreover, risk factors and their effects on serum lipid levels were analyzed using multivariable linear regression and logistic regression analyses. In Han and Maonan populations, a significant difference was found in the allelic and genotypic frequencies of the EHBP1 rs2710642 and rs10496099 SNPs and the alternate alleles of rs2710642A and rs10496099C might be potentially beneficial for healthy lipid levels. Medium linkage disequilibrium between the two SNPs was noted in each ethnic group, and four main haplotypes were detected. The rs2710642G-rs10496099C haplotype was associated with high triglycerides (TGs) and low high-density lipoprotein cholesterol, and the rs2710642A-rs10496099C haplotype was associated with low TGs and high apolipoprotein A1. The rs2710642G-rs10496099C haplotype was a high-risk factor for hyperlipidemia, and it interacted with smoking, fasting blood glucose, and hypertension to increase but with the female factor to decrease the prevalence of hyperlipidemia in Han individuals. The EHBP1 rs2710642 and rs10496099 SNPs and gene-environment interactions were associated with serum lipid profiles and hyperlipidemia, which is of ethnic specificity to our study populations.

Sex-Specific Determinants of Coronary Artery Disease and Atherosclerotic Risk Factors: Estrogen and Beyond

The way we view coronary artery disease in women has changed dramatically over the past decades. From an initial perspective that coronary artery disease was a male disorder and that women were protected by estrogens, there has been the gradual appreciation that this is an equal opportunity disease. Postmenopausal women are more likely than men to be hypertensive, dyslipidemic, and have multiple risk factors. Beyond the appreciation of estrogen's global effects on cardiovascular and metabolic function, our further advances in the understanding of sex-specific risks and management will be based on a greater understanding of the diversity of estrogen-mediated receptor pathways, including appreciation of the sometimes divergent effects of estrogen when acting either via the classic estrogen receptor or the more recently appreciated G protein-coupled estrogen receptor. In addition, the importance of sex-specific regulation of cardiometabolic processes beyond the sex hormones, specifically via SRY regulation, is only beginning to be understood. Finally, the author summarizes his recent studies demonstrating sex-specific G protein-coupled estrogen receptor regulation of blood pressure and cholesterol metabolism that may serve as a paradigm for the elucidation of sex-specific determinants of cardiovascular risk and the basis for sex-specific management of those risks.

Selected Sex Related Differences in Pathophysiology of Cardiovascular System

The annual incidence of cardiovascular diseases is age-dependently increasing both in men and women, however, the prevalence is higher in men until midlife. The higher incidence of cardiovascular disease in men than in women of similar age, and the menopause-associated increase in cardiovascular disease in women, has led to speculation that gender-related differences in sex hormones might have a key role in the development and evolution of cardiovascular disease. There are several suggested pathways in which gender and sex hormones can affect human cardiovascular system to produce original sexually different pathophysiology between women and men. Sex steroid hormones and their receptors are critical determinants of cardiovascular gender differences. Also arterial blood pressure is typically lower in women than in men what could be explained particularly by greater synthesis of nitric oxide (NO) in women. Female cardiomyocytes have a greater survival advantage when challenged with oxidative stress, suggesting that female hormones may play an important role in antioxidative protection of myocardium. It was also demonstrated in animal models that combination of XX chromosomes versus an XY chromosomes enhances sex differences in higher HDL cholesterol. Women were found to have reduced sympathetic activity (reflected by lower total peripheral resistance) and pulmonary artery pressure and enhanced parasympathetic activity relative to men. Similarly, men were found to have higher plasma norepinephrine levels than women. Regarding differences between the sexes in electrophysiology of the heart, two principle mechanisms have been proposed to explain them: hormonal effects on the expression or function of ion channels or, conversely, differences in autonomic tone. To improve diagnosis and treatment of cardiovascular diseases, greater focus on understanding the molecular and cellular physiology of the sex steroid hormones and their receptors in the cardiovascular system will be required.

XX sex chromosome complement promotes atherosclerosis in mice

Men and women differ in circulating lipids and coronary artery disease (CAD). While sex hormones such as estrogens decrease CAD risk, hormone replacement therapy increases risk. Biological sex is determined by sex hormones and chromosomes, but effects of sex chromosomes on circulating lipids and atherosclerosis are unknown. Here, we use mouse models to separate effects of sex chromosomes and hormones on atherosclerosis, circulating lipids and intestinal fat metabolism. We assess atherosclerosis in multiple models and experimental paradigms that distinguish effects of sex chromosomes, and male or female gonads. Pro-atherogenic lipids and atherosclerosis are greater in XX than XY mice, indicating a primary effect of sex chromosomes. Small intestine expression of enzymes involved in lipid absorption and chylomicron assembly are greater in XX male and female mice with higher intestinal lipids. Together, our results show that an XX sex chromosome complement promotes the bioavailability of dietary fat to accelerate atherosclerosis.

Men and women differ in their risk of developing coronary artery disease, in part due to differences in their levels of sex hormones. Here, AlSiraj et al. show that the XX sex genotype regulates lipid metabolism and promotes atherosclerosis independently of sex hormones in mice.

Y Chromosome, Hypertension and Cardiovascular Disease: Is Inflammation the Answer?

It is now becomingly increasingly evident that the functions of the mammalian Y chromosome are not circumscribed to the induction of male sex. While animal studies have shown variations in the Y are strongly accountable for blood pressure (BP), this is yet to be confirmed in humans. We have recently shown modulation of adaptive immunity to be a significant mechanism underpinning Y-chromosome-dependent differences in BP in consomic strains. This is paralleled by studies in man showing Y chromosome haplogroup is a significant predictor for coronary artery disease through influencing pathways of immunity. Furthermore, recent studies in mice and humans have shown that Y chromosome lineage determines susceptibility to autoimmune disease. Here we review the evidence in animals and humans that Y chromosome lineage influences hypertension and cardiovascular disease risk, with a novel focus on pathways of immunity as a significant pathway involved.

Cardiometabolic Effects of Testosterone in Transmen and Estrogen Plus Cyproterone Acetate in Transwomen

CONTEXT

The impact of gender-affirming hormone therapy (HT) on cardiometabolic parameters is largely unknown.

OBJECTIVE

The effects of 1 year of treatment with oral or transdermal administration of estrogen (plus cyproterone) and transdermal or IM application of testosterone on serum lipid levels and blood pressure (BP) were assessed in transgender persons.

DESIGN AND METHODS

In this prospective, observational substudy of the European Network for the Investigation of Gender Incongruence, measurements were performed before and after 12 months of HT in 242 transwomen and 188 transmen from 2010 to 2017.

RESULTS

Mean values are reported. In transmen, HT increased diastolic BP (2.5%; 95% CI, 0.6 to 4.4) and levels of total cholesterol (TC; 4.1%; 95% CI, 1.5 to 6.6), low-density lipoprotein-cholesterol (LDL-C; 13.0%; 95% CI, 9.2 to 16.8), and triglycerides (36.9%; 95% CI, 29.8 to 44.1); high-density lipoprotein-cholesterol levels decreased (HDL-C; 10.8%; 95% CI, -14.0 to -7.6). In transwomen, HT slightly decreased BP (systolic BP, -2.6%, 95% CI, -4.2 to -1.0; diastolic BP, -2.2%, 95% CI, -4.0 to -0.4) and decreased levels of TC (-9.7%; 95% CI, -11.3 to -8.1), LDL-C (-6.0%; 95% CI, -8.6 to 3.6), HDL-C (-9.3%; 95% CI, -11.4 to -7.3), and triglycerides (-10.2%; 95% CI, -14.5 to -5.9).

CONCLUSION

Unfavorable changes in lipid profile were observed in transmen; a favorable effect was noted in transwomen. HT effects on BP were negligible. Long-term studies are warranted to assess whether and to what extent HT in trans individuals results in a differential effect on cardiovascular disease outcomes.

Rethinking sex determination of non-gonadal tissues

Evolution of genetic mechanisms of sex determination led to two processes causing sex differences in somatic phenotypes: gonadal differentiation and sex chromosome dosage inequality. In species with heteromorphic sex chromosomes, the sex of the individual is established at the time of formation of the zygote, leading to inherent sex differences in expression of sex chromosome genes beginning as soon as the embryonic transcriptome is activated. The inequality of sex chromosome gene expression causes sexual differentiation of the gonads and of non-gonadal tissues. The difference in gonad type in turn causes lifelong differences in gonadal hormones, which interact with unequal effects of X and Y genes acting within cells. Separating the effects of gonadal hormones and sex chromosomes has been possible using mouse models in which gonadal determination is separated from the sex chromosomes, allowing comparison of XX and XY mice with the same type of gonad. Sex differences caused by gonadal hormones and sex chromosomes affect basic physiology and disease mechanisms in most or all tissues.