Sex- and Gender-Based Pharmacological Response to Drugs.

In humans, the combination of all sex-specific genetic, epigenetic, and hormonal influences of biologic sex produces different in vivo environments for male and female cells. We dissect how these influences of sex modify the pharmacokinetics and pharmacodynamics of multiple drugs and provide examples for common drugs acting on specific organ systems. We also discuss how gender of physicians and patients may influence the therapeutic response to drugs. We aim to highlight sex as a genetic modifier of the pharmacological response to drugs, which should be considered as a necessary step toward precision medicine that will benefit men and women. SIGNIFICANCE STATEMENT: This study discusses the influences of biologic sex on the pharmacokinetics and pharmacodynamics of drugs and provides examples for common drugs acting on specific organ systems. This study also discusses how gender of physicians and patients influence the therapeutic response to drugs.

Biological sex impacts COVID-19 outcomes.

The current novel coronavirus disease 2019 (COVID-19) pandemic is revealing profound differences between men and women in disease outcomes worldwide. In the United States, there has been inconsistent reporting and analyses of male-female differences in COVID-19 cases, hospitalizations, and deaths. We seek to raise awareness about the male-biased severe outcomes from COVID-19, highlighting the mechanistic differences including in the expression and activity of angiotensin-converting enzyme 2 (ACE2) as well as in antiviral immunity. We also highlight how sex differences in comorbidities, which can be associated with both age and race, impact male-biased outcomes from COVID-19.

Androgen-induced insulin resistance is ameliorated by deletion of hepatic androgen receptor in females.

Androgen excess is one of the most common endocrine disorders of reproductive-aged women, affecting up to 20% of this population. Women with elevated androgens often exhibit hyperinsulinemia and insulin resistance. The mechanisms of how elevated androgens affect metabolic function are not clear. Hyperandrogenemia in a dihydrotestosterone (DHT)-treated female mouse model induces whole body insulin resistance possibly through activation of the hepatic androgen receptor (AR). We investigated the role of hepatocyte AR in hyperandrogenemia-induced metabolic dysfunction by using several approaches to delete hepatic AR via animal-, cell-, and clinical-based methodologies. We conditionally disrupted hepatocyte AR in female mice developmentally (LivARKO) or acutely by tail vein injection of an adeno-associated virus with a liver-specific promoter for Cre expression in ARfl/fl mice (adLivARKO). We observed normal metabolic function in littermate female Control (ARfl/fl ) and LivARKO (ARfl/fl ; Cre+/- ) mice. Following chronic DHT treatment, female Control mice treated with DHT (Con-DHT) developed impaired glucose tolerance, pyruvate tolerance, and insulin tolerance, not observed in LivARKO mice treated with DHT (LivARKO-DHT). Furthermore, during an euglycemic hyperinsulinemic clamp, the glucose infusion rate was improved in LivARKO-DHT mice compared to Con-DHT mice. Liver from LivARKO, and primary hepatocytes derived from LivARKO, and adLivARKO mice were protected from DHT-induced insulin resistance and increased gluconeogenesis. These data support a paradigm in which elevated androgens in females disrupt metabolic function via hepatic AR and insulin sensitivity was restored by deletion of hepatic AR.

Sex differences in determinants of COVID-19 severe outcomes - findings from the National COVID Cohort Collaborative (N3C).

OBJECTIVE: The impact of comorbidities and biomarkers on COVID-19 severity vary by sex but have not yet been verified in population-based studies. We examined the association of comorbidities, inflammatory biomarkers, and severe outcomes in men and women hospitalized for COVID-19. DESIGN: This is a retrospective cohort analysis based on the National COVID Cohort Collaborative (N3C). We included 574,391 adult patients admitted for COVID-19 at hospitals or emergency rooms between 01/01/2020 and 12/31/2021. METHODS: We defined comorbidities at or before the first admission for COVID-19 by Charlson Comorbidity Index (CCI) and CCI components. We used the averaged lab values taken within 15 days before or after the admission date to measure biomarkers including c-reactive protein (CRP), ferritin, procalcitonin, N-terminal pro b-type natriuretic peptide (NT proBNP), d-dimer, absolute lymphocyte counts, absolute neutrophil counts, and platelets. Our primary outcome was all-cause mortality; secondary outcomes were invasive mechanical ventilation (IMV) and hospital length of stay (LOS). We used logistic regression adjusted for age, race, ethnicity, visit type, and medications to assess the association of comorbidities, biomarkers, and mortality disaggregating by sex. RESULTS: Moderate to severe liver disease, renal disease, metastatic solid tumor, and myocardial infarction were the top four fatal comorbidities among patients who were hospitalized for COVID-19 (adjusted odds ratio [aOR] > 2). These four comorbid conditions remained the most lethal in both sexes, with a higher magnitude of risk in women than in men (p-interaction < 0.05). Abnormal elevations of CRP, ferritin, procalcitonin, NT proBNP, neutrophil, and platelet counts, and lymphocytopenia were significantly associated with the risk of death, with procalcitonin and NT proBNP as the strongest predictors (aOR > 2). The association between the abnormal biomarkers and death was stronger in women than in men (p-interaction < 0.05). CONCLUSION: There are sex differences in inpatient mortality associated with comorbidities and biomarkers. The significant impact of these clinical determinants in women with COVID-19 may be underappreciated as previous studies stressed the increased death rate in male patients that is related to comorbidities or inflammation. Our study highlights the importance and the need for sex-disaggregated research to understand the risk factors of poor outcomes and health disparities in COVID-19.

Gender differences in health protective behaviours and its implications for COVID-19 pandemic in Taiwan: a population-based study.

INTRODUCTION: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection produces more severe symptoms and a higher mortality in men than in women. The role of biological sex in the immune response to SARS-CoV-2 is believed to explain this sex disparity. However, the contribution of gender factors that influence health protective behaviors and therefore health outcomes, remains poorly explored. METHODS: We assessed the contributions of gender in attitudes towards the COVID-19 pandemic, using a hypothetical influenza pandemic data from the 2019 Taiwan Social Change Survey. Participants were selected through a stratified, three-stage probability proportional-to-size sampling from across the nation, to fill in questionnaires that asked about their perception of the hypothetical pandemic, and intention to adopt health protective behaviors. RESULTS: A total of 1,990 participants (median age = 45·92 years, 49% were women) were included. Significant gender disparities (p < .001) were observed. The risk perception of pandemic (OR = 1·28, 95% CI [1·21 - 1·35], p < .001), older age (OR = 1·06, 95% CI [1·05 - 1·07], p < .001), female gender (OR = 1·18, 95% CI [1·09-1·27], p < .001), higher education (OR = 1·10, 95% CI [1·06 - 1·13], p < .001), and larger family size (OR = 1·09, 95% CI [1·06 - 1·15], p < .001) were positively associated with health protective behaviors. The risk perception of pandemic (OR = 1·25, 95% CI [1·15 - 1·36]), higher education (OR = 1·07, 95% CI [1·02 - 1·13], p < .05), being married (OR = 1·17, 95% CI [1·01-1·36, p < .05), and larger family size (OR = 1·33, 95% CI [1·25 - 1·42], p < .001), were positively associated with intention to receive a vaccine. However, female gender was negatively associated with intention to receive a vaccine (OR = 0·85, 95% CI [0·75 - 0·90], p < ·01) and to comply with contact-tracing (OR = 0·95, 95% CI [0·90 - 1·00], p < .05) compared to men. Living with children was also negatively associated with intention to receive vaccines (OR = 0·77, 95% CI [0·66 - 0·90], p < .001). CONCLUSION: This study unveils gender differences in risk perception, health protective behaviors, vaccine hesitancy, and compliance with contact-tracing using a hypothetical viral pandemic. Gender-specific health education raising awareness of health protective behaviors may be beneficial to prevent future pandemics.

Sex and gender: modifiers of health, disease, and medicine.

Clinicians can encounter sex and gender disparities in diagnostic and therapeutic responses. These disparities are noted in epidemiology, pathophysiology, clinical manifestations, disease progression, and response to treatment. This Review discusses the fundamental influences of sex and gender as modifiers of the major causes of death and morbidity. We articulate how the genetic, epigenetic, and hormonal influences of biological sex influence physiology and disease, and how the social constructs of gender affect the behaviour of the community, clinicians, and patients in the health-care system and interact with pathobiology. We aim to guide clinicians and researchers to consider sex and gender in their approach to diagnosis, prevention, and treatment of diseases as a necessary and fundamental step towards precision medicine, which will benefit men's and women's health.

Membrane-associated androgen receptor (AR) potentiates its transcriptional activities by activating heat shock protein 27 (HSP27).

The androgen receptor (AR) is a ligand-activated nuclear receptor that plays a critical role in normal prostate physiology, as well as in the development and progression of prostate cancer. In addition to the classical paradigm in which AR exerts its biological effects in the nucleus by orchestrating the expression of the androgen-regulated transcriptome, there is considerable evidence supporting a rapid, nongenomic activity mediated by membrane-associated AR. Although the genomic action of AR has been studied in depth, the molecular events governing AR transport to the plasma membrane and the downstream AR signaling cascades remain poorly understood. In this study, we report that AR membrane transport is microtubule-dependent. Disruption of the function of kinesin 5B (KIF5B), but not of kinesin C3 (KIFC3), interfered with AR membrane association and signaling. Co-immunoprecipitation and pulldown assays revealed that AR physically interacts with KIF5B and that androgen enhances this interaction. Furthermore, we show that heat shock protein 27 (HSP27) is activated by membrane-associated AR and that HSP27 plays an important role in mediating AR-mediated membrane-to-nuclear signal transduction. Together, these results indicate that AR membrane translocation is mediated by the microtubule cytoskeleton and the motor protein KIF5B. By activating HSP27, membrane-associated AR potentiates the transcriptional activity of nuclear AR. We conclude that disruption of AR membrane translocation may represent a potential strategy for targeting AR signaling therapeutically in prostate cancer.

Estrogen receptor α protects pancreatic ß-cells from apoptosis by preserving mitochondrial function and suppressing endoplasmic reticulum stress.

Estrogen receptor α (ERα) action plays an important role in pancreatic ß-cell function and survival; thus, it is considered a potential therapeutic target for the treatment of type 2 diabetes in women. However, the mechanisms underlying the protective effects of ERα remain unclear. Because ERα regulates mitochondrial metabolism in other cell types, we hypothesized that ERα may act to preserve insulin secretion and promote ß-cell survival by regulating mitochondrial-endoplasmic reticulum (EndoRetic) function. We tested this hypothesis using pancreatic islet-specific ERα knockout (PERαKO) mice and Min6 ß-cells in culture with Esr1 knockdown (KD). We found that Esr1-KD promoted reactive oxygen species production that associated with reduced fission/fusion dynamics and impaired mitophagy. Electron microscopy showed mitochondrial enlargement and a pro-fusion phenotype. Mitochondrial cristae and endoplasmic reticulum were dilated in Esr1-KD compared with ERα replete Min6 ß-cells. Increased expression of Oma1 and Chop was paralleled by increased oxygen consumption and apoptosis susceptibility in ERα-KD cells. In contrast, ERα overexpression and ligand activation reduced both Chop and Oma1 expression, likely by ERα binding to consensus estrogen-response element sites in the Oma1 and Chop promoters. Together, our findings suggest that ERα promotes ß-cell survival and insulin secretion through maintenance of mitochondrial fission/fusion-mitophagy dynamics and EndoRetic function, in part by Oma1 and Chop repression.

Nischarin inhibition alters energy metabolism by activating AMP-activated protein kinase.

Nischarin (Nisch) is a key protein functioning as a molecular scaffold and thereby hosting interactions with several protein partners. To explore the physiological importance of Nisch, here we generated Nisch loss-of-function mutant mice and analyzed their metabolic phenotype. Nisch-mutant embryos exhibited delayed development, characterized by small size and attenuated weight gain. We uncovered the reason for this phenotype by showing that Nisch binds to and inhibits the activity of AMP-activated protein kinase (AMPK), which regulates energy homeostasis by suppressing anabolic and activating catabolic processes. The Nisch mutations enhanced AMPK activation and inhibited mechanistic target of rapamycin signaling in mouse embryonic fibroblasts as well as in muscle and liver tissues of mutant mice. Nisch-mutant mice also exhibited increased rates of glucose oxidation with increased energy expenditure, despite reduced overall food intake. Moreover, the Nisch-mutant mice had reduced expression of liver markers of gluconeogenesis associated with increased glucose tolerance. As a result, these mice displayed decreased growth and body weight. Taken together, our results indicate that Nisch is an important AMPK inhibitor and a critical regulator of energy homeostasis, including lipid and glucose metabolism.

Perinatal Exposure to Western Diet Programs Autonomic Dysfunction in the Male Offspring.

Although the deleterious influence of protein deficiency on fetal programming is well documented, the impact of a Western diet on epigenetic mechanisms is less clear. We hypothesized that high-fat high-sucrose diet (HFHSD) consumption during pregnancy leads to epigenetic modifications within the progeny's compensatory renin-angiotensin system (RAS), affecting autonomic and metabolic functions. Dams were fed HFHSD (45% fat and 30% sucrose) or regular chow (RD) from mating until weaning of the pups (~7 weeks). Offspring from both groups were then maintained on chow and studied in adulthood (3-7 months). Offspring from HFHSD-exposed dams (OH) exhibited no difference in body weight or fasting blood glucose compared to controls (OR). In 3-month-old offspring, DNA methylation was significantly lower for the ACE2 gene (P < 0.05) in the brainstem, kidney and cecum. Moreover, ACE2 activity in the hypothalamus was increased at 7 months (OH: 91 ± 1 vs. OR: 74 ± 4 AFU/mg/min, P < 0.05). Although baseline blood pressure was not different between groups, vagal tone in OH was significantly impaired compared to OR. At the same time, OH offspring had a 1.7-fold increase in AT1a receptor expression and a 1.3-fold increase in ADAM17 mRNA. DOCA-salt treatment further revealed and exacerbated hypertensive response in the OH progeny (OH: 130 ± 6 vs. OR: 108 ± 3 mmHg, P < 0.05). Taken together, our data suggest that perinatal exposure to HFHSD resulted in epigenetic modifications of the compensatory brain RAS, potentially affecting plasticity of neuronal networks leading to autonomic dysfunction in the male offspring.

KCNJ11, ABCC8 and TCF7L2 polymorphisms and the response to sulfonylurea treatment in patients with type 2 diabetes: a bioinformatics assessment.

BACKGROUND: Type 2 diabetes (T2D) is a worldwide epidemic with considerable health and economic consequences. Sulfonylureas are widely used drugs for the treatment of patients with T2D. KCNJ11 and ABCC8 encode the Kir6.2 (pore-forming subunit) and SUR1 (regulatory subunit that binds to sulfonylurea) of pancreatic ß cell KATP channel respectively with a critical role in insulin secretion and glucose homeostasis. TCF7L2 encodes a transcription factor expressed in pancreatic ß cells that regulates insulin production and processing. Because mutations of these genes could affect insulin secretion stimulated by sulfonylureas, the aim of this study is to assess associations between molecular variants of KCNJ11, ABCC8 and TCF7L2 genes and response to sulfonylurea treatment and to predict their potential functional effects. METHODS: Based on a comprehensive literature search, we found 13 pharmacogenetic studies showing that single nucleotide polymorphisms (SNPs) located in KCNJ11: rs5219 (E23K), ABCC8: rs757110 (A1369S), rs1799854 (intron 15, exon 16 -3C/T), rs1799859 (R1273R), and TCF7L2: rs7903146 (intron 4) were significantly associated with responses to sulfonylureas. For in silico bioinformatics analysis, SIFT, PolyPhen-2, PANTHER, MutPred, and SNPs3D were applied for functional predictions of 36 coding (KCNJ11: 10, ABCC8: 24, and TCF7L2: 2; all are missense), and HaploReg v4.1, RegulomeDB, and Ensembl's VEP were used to predict functions of 7 non-coding (KCNJ11: 1, ABCC8: 1, and TCF7L2: 5) SNPs, respectively. RESULTS: Based on various in silico tools, 8 KCNJ11 missense SNPs, 23 ABCC8 missense SNPs, and 2 TCF7L2 missense SNPs could affect protein functions. Of them, previous studies showed that mutant alleles of 4 KCNJ11 missense SNPs and 5 ABCC8 missense SNPs can be successfully rescued by sulfonylurea treatments. Further, 3 TCF7L2 non-coding SNPs (rs7903146, rs11196205 and rs12255372), can change motif(s) based on HaploReg v4.1 and are predicted as risk factors by Ensembl's VEP. CONCLUSIONS: Our study indicates that a personalized medicine approach by tailoring sulfonylurea therapy of T2D patients according to their genotypes of KCNJ11, ABCC8, and TCF7L2 could attain an optimal treatment efficacy.

PAX4 Gene Transfer Induces α-to-ß Cell Phenotypic Conversion and Confers Therapeutic Benefits for Diabetes Treatment.

The transcription factor Pax4 plays a critical role in the determination of α- versus ß-cell lineage during endocrine pancreas development. In this study, we explored whether Pax4 gene transfer into α-cells could convert them into functional ß-cells and thus provide therapeutic benefits for insulin-deficient diabetes. We found that Pax4 delivered by adenoviral vector, Ad5.Pax4, induced insulin expression and reduced glucagon expression in αTC1.9 cells. More importantly, these cells exhibited glucose-stimulated insulin secretion, a key feature of functional ß-cells. When injected into streptozotocin-induced diabetic mice, Pax4-treated αTC1.9 cells significantly reduced blood glucose, and the mice showed better glucose tolerance, supporting that Pax4 gene transfer into αTC1.9 cells resulted in the formation of functional ß-cells. Furthermore, treatment of primary human islets with Ad5.Pax4 resulted in significantly improved ß-cell function. Detection of glucagon(+)/Pax4(+)/Insulin(+) cells argued for Pax4-induced α-to-ß cell transitioning. This was further supported by quantification of glucagon and insulin bi-hormonal cells, which was significantly higher in Pax4-treated islets than in controls. Finally, direct administration of Ad5.Pax4 into the pancreas of insulin-deficient mice ameliorated hyperglycemia. Taken together, our data demonstrate that manipulating Pax4 gene expression represents a viable therapeutic strategy for the treatment of insulin deficient diabetes.

Epidemiology of Gender Differences in Diabetes and Obesity.

Some aspects of glucose homeostasis and energy balance are regulated differently in males and females. This review discusses the most fundamental gender differences in diabetes and obesity, including the prevalence of impaired fasting glucose and impaired glucose tolerance, the prevalence and incidence of type 2 and type 1 diabetes, as well as the prevalence of metabolic syndrome and obesity. These gender-specific differences in glucose homeostasis and energy balance represent a source of factors that should be studied to develop gender-based therapeutic avenues for diabetes.

Menopause, Estrogens, and Glucose Homeostasis in Women.

Randomized trials suggest that menopausal hormone therapy (MHT) prevents type 2 diabetes. Still, the mechanisms of these antidiabetic effects are a matter of controversy. This chapter provides an analysis of epidemiological and clinical evidence and proposes a mechanism for the effect of menopause and MHT on type 2 diabetes development and prevention. It discusses the beneficial role of estradiol on glucose homeostasis that is lost at menopause and improved by MHT, which delays type 2 diabetes. This chapter aims to reconcile differences among studies of the effect of menopause and MHT formulations on type 2 diabetes and argues that discrepancies arise from physiological differences in methods used to assess glucose homeostasis.

The Role of Estrogens in Pancreatic Islet Physiopathology.

In rodent models of insulin-deficient diabetes, 17ß-estradiol (E2) protects pancreatic insulin-producing ß-cells against oxidative stress, amyloid polypeptide toxicity, gluco-lipotoxicity, and apoptosis. Three estrogen receptors (ERs)-ERα, ERß, and the G protein-coupled ER (GPER)-have been identified in rodent and human ß-cells. This chapter describes recent advances in our understanding of the role of ERs in islet ß-cell function, nutrient homeostasis, survival from pro-apoptotic stimuli, and proliferation. We discuss why and how ERs represent potential therapeutic targets for the maintenance of functional ß-cell mass.

Sex differences in energy metabolism: natural selection, mechanisms and consequences.

Metabolic homeostasis operates differently in men and women. This sex asymmetry is the result of evolutionary adaptations that enable women to resist loss of energy stores and protein mass while remaining fertile in times of energy deficit. During starvation or prolonged exercise, women rely on oxidation of lipids, which are a more efficient energy source than carbohydrates, to preserve glucose for neuronal and placental function and spare proteins necessary for organ function. Carbohydrate reliance in men could be an evolutionary adaptation related to defence and hunting, as glucose, unlike lipids, can be used as a fuel for anaerobic high-exertion muscle activity. The larger subcutaneous adipose tissue depots in healthy women than in healthy men provide a mechanism for lipid storage. As female mitochondria have higher functional capacity and greater resistance to oxidative damage than male mitochondria, uniparental inheritance of female mitochondria may reduce the transmission of metabolic disorders. However, in women, starvation resistance and propensity to obesity have evolved in tandem, and the current prevalence of obesity is greater in women than in men. The combination of genetic sex, programming by developmental testosterone in males, and pubertal sex hormones defines sex-specific biological systems in adults that produce phenotypic sex differences in energy homeostasis, metabolic disease and drug responses.

Single cell regulatory architecture of human pancreatic islets suggests sex differences in ß cell function and the pathogenesis of type 2 diabetes.

Type 2 and type 1 diabetes (T2D, T1D) exhibit sex differences in insulin secretion, the mechanisms of which are unknown. We examined sex differences in human pancreatic islets from 52 donors with and without T2D combining single cell RNA-seq (scRNA-seq), single nucleus assay for transposase-accessible chromatin sequencing (snATAC-seq), hormone secretion, and bioenergetics. In nondiabetic (ND) donors, sex differences in islet cells gene accessibility and expression predominantly involved sex chromosomes. Islets from T2D donors exhibited similar sex differences in sex chromosomes differentially expressed genes (DEGs), but also exhibited sex differences in autosomal genes. Comparing ß cells from T2D vs. ND donors, gene enrichment of female ß cells showed suppression in mitochondrial respiration, while male ß cells exhibited suppressed insulin secretion. Thus, although sex differences in gene accessibility and expression of ND ß cells predominantly affect sex chromosomes, the transition to T2D reveals sex differences in autosomes highlighting mitochondrial failure in females.

Maternal Western diet programs cardiometabolic dysfunction and hypothalamic inflammation via epigenetic mechanisms predominantly in the male offspring.

OBJECTIVE: Maternal exposure during pregnancy is a strong determinant of offspring health outcomes. Such exposure induces changes in the offspring epigenome resulting in gene expression and functional changes. In this study, we investigated the effect of maternal Western hypercaloric diet (HCD) programming during the perinatal period on neuronal plasticity and cardiometabolic health in adult offspring. METHODS: C57BL/6J dams were fed HCD for 1 month prior to mating with regular diet (RD) sires and kept on the same diet throughout pregnancy and lactation. At weaning, offspring were maintained on either HCD or RD for 3 months resulting in 4 treatment groups that underwent cardiometabolic assessments. DNA and RNA were extracted from the hypothalamus to perform whole genome methylation, mRNA, and miRNA sequencing followed by bioinformatic analyses. RESULTS: Maternal programming resulted in male-specific hypertension and hyperglycemia, with both males and females showing increased sympathetic tone to the vasculature. Surprisingly, programmed male offspring fed HCD in adulthood exhibited lower glucose levels, less insulin resistance, and leptin levels compared to non-programmed HCD-fed male mice. Hypothalamic genes involved in inflammation and type 2 diabetes were targeted by differentially expressed miRNA, while genes involved in glial and astrocytic differentiation were differentially methylated in programmed male offspring. These data were supported by our findings of astrogliosis, microgliosis and increased microglial activation in programmed males in the paraventricular nucleus (PVN). Programming induced a protective effect in male mice fed HCD in adulthood, resulting in lower protein levels of hypothalamic TGFß2, NF-κB2, NF-κBp65, Ser-pIRS1, and GLP1R compared to non-programmed HCD-fed males. Although TGFß2 was upregulated in male mice exposed to HCD pre- or post-natally, only blockade of the brain TGFß receptor in RD-HCD mice improved glucose tolerance and a trend to weight loss. CONCLUSIONS: Our study shows that maternal HCD programs neuronal plasticity in the offspring and results in male-specific hypertension and hyperglycemia associated with hypothalamic inflammation in mechanisms and pathways distinct from post-natal HCD exposure. Together, our data unmask a compensatory role of HCD programming, likely via priming of metabolic pathways to handle excess nutrients in a more efficient way.

Testosterone deficiency promotes arterial stiffening independent of sex chromosome complement.

BACKGROUND: Sex hormones and sex chromosomes play a vital role in cardiovascular disease. Testosterone plays a crucial role in men's health. Lower testosterone level is associated with cardiovascular and cardiometabolic diseases, including inflammation, atherosclerosis, and type 2 diabetes. Testosterone replacement is beneficial or neutral to men's cardiovascular health. Testosterone deficiency is associated with cardiovascular events. Testosterone supplementation to hypogonadal men improves libido, increases muscle strength, and enhances mood. We hypothesized that sex chromosomes (XX and XY) interaction with testosterone plays a role in arterial stiffening. METHODS: We used four core genotype male mice to understand the inherent contribution of sex hormones and sex chromosome complement in arterial stiffening. Age-matched mice were either gonadal intact or castrated at eight weeks plus an additional eight weeks to clear endogenous sex hormones. This was followed by assessing blood pressure, pulse wave velocity, echocardiography, and ex vivo passive vascular mechanics. RESULTS: Arterial stiffening but not blood pressure was more significant in castrated than testes-intact mice independent of sex chromosome complement. Castrated mice showed a leftward shift in stress-strain curves and carotid wall thinning. Sex chromosome complement (XX) in the absence of testosterone increased collagen deposition in the aorta and Kdm6a gene expression. CONCLUSION: Testosterone deprivation increases arterial stiffening and vascular wall remodeling. Castration increases Col1α1 in male mice with XX sex chromosome complement. Our study shows decreased aortic contractile genes in castrated mice with XX than XY sex chromosomes.

Cardiovascular disease is the leading cause of death worldwide. Cardiovascular disease presents differently in men and women. While men develop plaque buildup in large arteries, women develop buildup in the microvessels in the heart. Arterial stiffening, which is the hardening of arteries, increases with age in both men and women. Aging, coupled with the decline in sex hormones, exacerbates cardiovascular disease in women compared to men. Men with XY sex chromosomes have higher circulating testosterone, while women with XX sex chromosomes have increased circulating estradiol. The potential benefits of sex hormone replacement therapy are shown in men and women. Indeed, testosterone replacement deficiency is associated with adverse cardiovascular outcomes in men. Whether adverse events are dependent or independent of sex hormones' interaction with sex chromosomes is unknown. This study used the four core genotype mice comprising males with either XX or XY sex chromosome complement. We show castration increases arterial stiffening and collagen deposition on the arterial wall. We also identified the escapee and smooth muscle contractile genes that may play a role in arterial stiffening. Our data suggests that testosterone deprivation mediates arterial stiffening and remodeling.