Sex-specific sequels of early life stress on serine/threonine kinase activity in visceral adipose tissue from obese mice.

Adverse childhood experiences (ACEs) are an established independent risk factor for chronic disease including obesity and hypertension; however, only women exposed to multiple ACEs show a positive relationship with BMI. Our lab has reported that maternal separation and early weaning (MSEW), a mouse model of early life stress, induces sex-specific mechanisms underlying greater blood pressure response to a chronic high fat diet (HF). Specifically, female MSEW mice fed a HF display exacerbated perigonadal white adipose tissue (pgWAT) expansion and a metabolic syndrome-like phenotype compared to control counterparts, whereas hypertension is caused by sympathoactivation in male MSEW mice. Thus, this study aimed to determine whether there is a sex-specific serine/threonine kinase (STKA) activity in pgWAT adipose tissue associated with early life stress. Frozen pgWAT was collected from MSEW and control, male and female mice fed a HF to assess STKA activity using the Pamstation12 instrument. Overall, MSEW induces significant reduction of 7 phosphokinases (|Z| >=1.5) in females (QIK, MLK, PKCH, MST, STE7, PEK, FRAY) and 5 in males (AKT, SGK, P38, MARK, CDK), while 15 were downregulated in both sexes (DMPK, PKA, PKG, RSK, PLK, DYRK, NMO, CAMK1, JNK, PAKA, RAD53, ERK, PAKB, PKD, PIM, AMPK). This data provides new insights into the sex-specific dysregulation of the molecular network controlling cellular phosphorylation signals in visceral adipose tissue and identifies possible target phosphokinases implicated in adipocyte hypertrophy as a result of exposure to early life stress. Identifying functional metabolic signatures is critical to elucidate the underlying molecular mechanisms behind the sex-specific obesity risk associated with early life stress.

Obese Male Mice Exposed to Early Life Stress Display Sympathetic Activation and Hypertension Independent of Circulating Angiotensin II.

BACKGROUND: We have previously reported that male mice exposed to maternal separation and early weaning (MSEW), a model of early life stress, show sympathetic activation and increased blood pressure in response to a chronic high-fat diet. The goal of this study was to investigate the contribution of the renin-angiotensin-aldosterone system to the mechanism by which MSEW increases blood pressure and vasomotor sympathetic tone in obese male mice. METHODS AND RESULTS: Mice were exposed to MSEW during postnatal life. Undisturbed litters served as controls. At weaning, both control and MSEW offspring were placed on a low-fat diet or a high-fat diet for 20 weeks. Angiotensin peptides in serum were similar in control and MSEW mice regardless of the diet. However, a high-fat diet induced a similar increase in angiotensinogen levels in serum, renal cortex, liver, and fat in both control and MSEW mice. No evidence of renin-angiotensin system activation was found in adipose tissue and renal cortex. After chronic treatment with enalapril (2.5 mg/kg per day, drinking water, 7 days), an angiotensin-converting enzyme inhibitor that does not cross the blood-brain barrier, induced a similar reduction in blood pressure in both groups, while the vasomotor sympathetic tone remained increased in obese MSEW mice. In addition, acute boluses of angiotensin II (1, 10, 50 µg/kg s.c.) exerted a similar pressor response in MSEW and control mice before and after enalapril treatment. CONCLUSIONS: Overall, elevated blood pressure and vasomotor sympathetic tone remained exacerbated in MSEW mice compared with controls after the peripheral inhibition of angiotensin-converting enzyme, suggesting a mechanism independent of angiotensin II.

Prenatal Morphine Exposure Increases Cardiovascular Disease Risk and Programs Neurogenic Hypertension in the Adult Offspring.

BACKGROUND: The opioid overdose and opioid use disorder epidemics are concomitant with increased metabolic and CVD risk. Although opioid use disorder causes adverse pregnancy outcomes, the offspring's cardiovascular health is understudied. We hypothesized that offspring exposed to in utero morphine exposure (IUME) would show increased CVD risk factors and endogenous opioid system dysregulation. METHODS: Sprague Dawley dams were treated with saline (vehicle, n=10) or escalating doses of morphine (5-20 mg/kg per day, SC, n=10) during gestation. Cardiovascular and metabolic parameters were assessed in adult offspring. RESULTS: Litter size and pups' birth weight were not different in response to IUME. Female and male IUME offspring showed reduced body length at birth (P<0.05) and body weight from weeks 1 to 3 of life (P<0.05), followed by a catch-up growth effect. By week 16, female and male IUME rats showed reduced tibia length (P<0.05) and fat mass. IUME increases the mean arterial pressure and the depressor response to mecamylamine (5 mg/kg per day, IP) induced by IUME were abolished by a chronic treatment with an alpha-adrenergic receptor blocker (prazosin; 1 mg/kg per day, IP). Although circulating levels of angiotensin peptides were similar between groups, IUME exacerbated maximal ex vivo Ang (angiotensin) II-induced vasoconstriction (P<0.05) and induced endothelial dysfunction in a sex-specific manner (P<0.05). Proenkephalin, an endogenous opioid peptide that lowers blood pressure and sympathetic-mediated vasoconstriction, showed reduced mRNA expression in the heart, aorta, and kidneys from morphine versus vehicle group (P<0.05). CONCLUSIONS: Among the effects of IUME, neurogenic hypertension, vascular dysfunction, and metabolic dysfunction could be associated with the dysregulation of the endogenous opioid system.

Sex and race define the effects of adverse childhood experiences on self-reported BMI and metabolic health biomarkers.

BACKGROUND: Adverse childhood experiences (ACEs) are an independent risk factor for chronic diseases, including type 2 diabetes, stroke and ischemic heart disease. However, the effect of ACEs considering sex and race are not often reported in cohorts showing multiracial composition, with power to evaluate effects on underrepresented populations. AIM: To determine how sex and race affected the association of combined and individual ACEs with metabolic health biomarkers in the Southern Community Cohort Study (2012-2015). METHODS: Self-reported data were analyzed from ACE surveys performed during the second follow-up of a cohort comprised by over 60% of Black subjects and with an overall mean age of 60 years. RESULTS: BMI steadily increased with cumulative ACEs among Black and White women, but remained relatively stable in White men with ≥ 4 ACEs. Contrary, Black men showed an inverse association between ACE and BMI. Secondary analysis of metabolic outcomes showed that physical abuse was correlated with a 4.85 cm increase in waist circumference in Black subjects. Total cholesterol increased among individuals with more than 4 ACEs. In addition, increases in HbA1c were associated with emotional and maternal abuse in Black women and sexual abuse in White women. CONCLUSIONS: BMI is strongly associated with cumulative ACEs in women regardless the race, while waist circumference is strongly associated with ACEs in Black individuals, which combined with reduced BMI may indicate increased central adiposity in Black men. Our study suggests that sex and race influence the contribution of certain ACEs to impair metabolic health.

Early life stress exacerbates obesity in adult female mice via mineralocorticoid receptor-dependent increases in adipocyte triglyceride and glycerol content.

Previously, we have shown that Maternal Separation and Early Weaning (MSEW) exacerbates high fat diet (HF)-induced visceral obesity in female offspring compared to normally reared female mice. Stress hormones such as glucocorticoids and mineralocorticoids are critical mediators in the process of fat expansion, and both can activate the mineralocorticoid receptor (MR) in the adipocyte. Therefore, this study aimed to, comprehend the specific effects of MSEW on adipose tissue basic homeostatic function, and investigate whether female MSEW mice show an exacerbated obesogenic response mediated by MR. Gonadal white adipose tissue (gWAT), a type of visceral fat, was collected to assess lipidomics, transcriptomics, and in vitro lipolysis assay. Obese female MSEW mice showed increased adiposity, elevated 44:2/FA 18:2 + NH4 lipid class and reduced mitochondrial DNA density compared to obese control counterparts. In addition, single-cell RNA sequencing in isolated pre- and mature adipocytes showed a ~9-fold downregulation of aquaglycerolporin 3 (Aqp3), a channel responsible for glycerol efflux in adipocytes. Obese MSEW mice showed high levels of circulating aldosterone and gWAT-derived corticosterone compared to controls. Further, the MR blocker spironolactone (Spiro, 100 mg/kg/day, 2 weeks) normalized the elevated intracellular glycerol levels, the greater in vitro lipolysis response, and the number of large size adipocytes in MSEW mice compared to the controls. Our data suggests that MR plays a role promoting adipocyte hypertrophy in female MSEW mice by preventing lipolysis via glycerol release in favor of triglyceride formation and storage.

Association of Rare APOE Missense Variants V236E and R251G With Risk of Alzheimer Disease.

Importance: The APOE ε2 and APOE ε4 alleles are the strongest protective and risk-increasing, respectively, genetic variants for late-onset Alzheimer disease (AD). However, the mechanisms linking APOE to AD-particularly the apoE protein's role in AD pathogenesis and how this is affected by APOE variants-remain poorly understood. Identifying missense variants in addition to APOE ε2 and APOE ε4 could provide critical new insights, but given the low frequency of additional missense variants, AD genetic cohorts have previously been too small to interrogate this question robustly. Objective: To determine whether rare missense variants on APOE are associated with AD risk. Design, Setting, and Participants: Association with case-control status was tested in a sequenced discovery sample (stage 1) and followed up in several microarray imputed cohorts as well as the UK Biobank whole-exome sequencing resource using a proxy-AD phenotype (stages 2 and 3). This study combined case-control, family-based, population-based, and longitudinal AD-related cohorts that recruited referred and volunteer participants. Stage 1 included 37 409 nonunique participants of European or admixed European ancestry, with 11 868 individuals with AD and 11 934 controls passing analysis inclusion criteria. In stages 2 and 3, 475 473 participants were considered across 8 cohorts, of which 84 513 individuals with AD and proxy-AD and 328 372 controls passed inclusion criteria. Selection criteria were cohort specific, and this study was performed a posteriori on individuals who were genotyped. Among the available genotypes, 76 195 were excluded. All data were retrieved between September 2015 and November 2021 and analyzed between April and November 2021. Main Outcomes and Measures: In primary analyses, the AD risk associated with each missense variant was estimated, as appropriate, with either linear mixed-model regression or logistic regression. In secondary analyses, associations were estimated with age at onset using linear mixed-model regression and risk of conversion to AD using competing-risk regression. Results: A total of 544 384 participants were analyzed in the primary case-control analysis; 312 476 (57.4%) were female, and the mean (SD; range) age was 64.9 (15.2; 40-110) years. Two missense variants were associated with a 2-fold to 3-fold decreased AD risk: APOE ε4 (R251G) (odds ratio, 0.44; 95% CI, 0.33-0.59; P = 4.7 × 10-8) and APOE ε3 (V236E) (odds ratio, 0.37; 95% CI, 0.25-0.56; P = 1.9 × 10-6). Additionally, the cumulative incidence of AD in carriers of these variants was found to grow more slowly with age compared with noncarriers. Conclusions and Relevance: In this genetic association study, a novel variant associated with AD was identified: R251G always coinherited with ε4 on the APOE gene, which mitigates the ε4-associated AD risk. The protective effect of the V236E variant, which is always coinherited with ε3 on the APOE gene, was also confirmed. The location of these variants confirms that the carboxyl-terminal portion of apoE plays an important role in AD pathogenesis. The large risk reductions reported here suggest that protein chemistry and functional assays of these variants should be pursued, as they have the potential to guide drug development targeting APOE.

Consequences of hyperandrogenemia during pregnancy in female offspring: attenuated response to angiotensin II.

BACKGROUND: Polycystic ovary syndrome (PCOS) is characterized by reproductive and metabolic dysfunction, and elevated blood pressure (BP). The cardiometabolic consequences of maternal hyperandrogenemia on offspring, either as adults or with aging, have not been well studied. We previously found that male offspring of hyperandrogenemic female (HAF) rats, a model of PCOS, are normotensive but have an exaggerated pressor response to angiotensin (Ang) II. METHOD: In this study, the hypothesis was tested that adult and aging female offspring of HAF rats develop a metabolic and hypertensive phenotype. Control and HAF rats were implanted prepubertally with placebo or dihydrotestosterone pellets, which continued throughout pregnancy and lactation. RESULTS: Female offspring of HAF dams had lower birth weight than female control offspring. Although female HAF offspring (aged 16-24 weeks) had no differences in intrarenal Ang II, plasma lipids or proteinuria, they did have lower intrarenal Ang (1-7) and lower nitrate/nitrite excretion than controls. Adult HAF offspring had similar baseline BP as controls, but had an attenuated pressor response to Ang II. With aging (16-20 months), female HAF offspring remained normotensive with an attenuated pressor response to Ang II and high salt diet but more proteinuria and higher intrarenal Ang(1-7) than controls. CONCLUSION: Taken together, these data suggest that female HAF offspring are protected from developing hypertension, but may be at risk for renal injury with aging. Future studies are necessary to determine whether adult and postmenopausal offspring of PCOS women are at increased risk for cardiovascular dysfunction.Graphical abstract:http://links.lww.com/HJH/B820.

Epididymal Fat-Derived Sympathoexcitatory Signals Exacerbate Neurogenic Hypertension in Obese Male Mice Exposed to Early Life Stress.

[Figure: see text].

Cardiometabolic consequences of maternal hyperandrogenemia in male offspring.

Polycystic ovary syndrome (PCOS) in women is characterized by hyperandrogenemia, obesity, and oligo- or anovulation. In addition, women with PCOS are often obese, with insulin resistance, hyperlipidemia, and elevated blood pressure. The cardiometabolic consequences for the male offspring of maternal hyperandrogenemia are unclear. The present studies tested the hypothesis that male offspring of a rat model of PCOS would develop cardiometabolic disease as adults. Female Sprague-Dawley rats (hyperandrogenemic females (HAF)) were implanted with dihydrotestosterone or placebo pellets (controls) at 4 weeks of age, and were mated at 10-12 weeks and allowed to lactate their offspring after birth. Body weights in male HAF offspring were lower at birth than in controls until postnatal day 4, but body weights remained similar between male control and HAF offspring from 2 to 8 weeks of age. However, at 16 weeks of age, body weight was lower in HAF male offspring, but there were no differences in fat mass or lean mass factored for body weight in HAF males, compared to controls. Plasma total cholesterol and HDL and proteinuria were higher and nitrate/nitrite excretion was lower in male HAF offspring than in controls. Baseline blood pressure was similar between HAF male offspring and controls, but HAF offspring had an exaggerated pressor response to angiotensin II infusion. These data suggest that adult sons of PCOS mothers may be at increased risk of cardiometabolic disease.

Corrigendum: Intrarenal Renin Angiotensin System Imbalance During Postnatal Life Is Associated With Increased Microvascular Density in the Mature Kidney.

[This corrects the article DOI: 10.3389/fphys.2020.01046.].

Intrarenal Renin Angiotensin System Imbalance During Postnatal Life Is Associated With Increased Microvascular Density in the Mature Kidney.

Environmental stress during early life is an important factor that affects the postnatal renal development. We have previously shown that male rats exposed to maternal separation (MatSep), a model of early life stress, are normotensive but display a sex-specific reduced renal function and exacerbated angiotensin II (AngII)-mediated vascular responses as adults. Since optimal AngII levels during postnatal life are required for normal maturation of the kidney, this study was designed to investigate both short- and long-term effect of MatSep on (1) the renal vascular architecture and function, (2) the intrarenal renin-angiotensin system (RAS) components status, and (3) the genome-wide expression of genes in isolated renal vasculature. Renal tissue and plasma were collected from male rats at different postnatal days (P) for intrarenal RAS components mRNA and protein expression measurements at P2, 6, 10, 14, 21, and 90 and microCT analysis at P21 and 90. Although with similar body weight and renal mass trajectories from P2 to P90, MatSep rats displayed decreased renal filtration capacity at P90, while increased microvascular density at both P21 and P90 (p < 0.05). MatSep increased renal expression of renin, and angiotensin type 1 (AT1) and type 2 (AT2) receptors (p < 0.05), but reduced ACE2 mRNA expression and activity from P2-14 compared to controls. However, intrarenal levels of AngII peptide were reduced (p < 0.05) possible due to the increased degradation to AngIII by aminopeptidase A. In isolated renal vasculature from neonates, Enriched Biological Pathways functional clusters (EBPfc) from genes changed by MatSep reported to modulate extracellular structure organization, inflammation, and pro-angiogenic transcription factors. Our data suggest that male neonates exposed to MatSep could display permanent changes in the renal microvascular architecture in response to intrarenal RAS imbalance in the context of the atypical upregulation of angiogenic factors.

Pregnancy Protects Hyperandrogenemic Female Rats From Postmenopausal Hypertension.

Polycystic ovary syndrome, the most common endocrine disorder in women of reproductive age, is characterized by hyperandrogenemia, obesity, insulin resistance, and elevated blood pressure. However, few studies have focused on the consequences of pregnancy on postmenopausal cardiovascular disease and hypertension in polycystic ovary syndrome women. In hyperandrogenemic female (HAF) rats, the hypothesis was tested that previous pregnancy protects against age-related hypertension. Rats were implanted with dihydrotestosterone (7.5 mg/90 days, beginning at 4 weeks and continued throughout life) or placebo pellets (controls), became pregnant at 10 to 15 weeks, and pups were weaned at postnatal day 21. Dams and virgins were then aged to 10 months (still estrous cycling) or 16 months (postcycling). Although numbers of offspring per litter were similar for HAF and control dams, birth weights were lower in HAF offspring. At 10 months of age, there were no differences in blood pressure, proteinuria, nitrate/nitrite excretion, or body composition in previously pregnant HAF versus virgin HAF. However, by 16 months of age, despite no differences in dihydrotestosterone, fat mass/or lean mass/body weight, previously pregnant HAF had significantly lower blood pressure and proteinuria, higher nitrate/nitrite excretion, with increased intrarenal mRNA expression of endothelin B receptor and eNOS (endothelial nitric oxide synthase), and decreased ACE (angiotensin-converting enzyme), AT1aR (angiotensin 1a receptor), and endothelin A receptor than virgin HAF. Thus, pregnancy protects HAF rats against age-related hypertension, and the mechanism(s) may be due to differential regulation of the nitric oxide, endothelin, and renin-angiotensin systems. These data suggest that polycystic ovary syndrome women who have experienced uncomplicated pregnancy may be protected from postmenopausal hypertension.

Sensory signals mediating high blood pressure via sympathetic activation: role of adipose afferent reflex.

Blood pressure regulation in health and disease involves a balance between afferent and efferent signals from multiple organs and tissues. Although there are numerous reviews focused on the role of sympathetic nerves in different models of hypertension, few have revised the contribution of afferent nerves innervating adipose tissue and their role in the development of obesity-induced hypertension. Both clinical and basic research support the beneficial effects of bilateral renal denervation in lowering blood pressure. However, recent studies revealed that afferent signals from adipose tissue, in an adipose-brain-peripheral pathway, could contribute to the increased sympathetic activation and blood pressure during obesity. This review focuses on the role of adipose tissue afferent reflexes and briefly describes a number of other afferent reflexes modulating blood pressure. A comprehensive understanding of how multiple afferent reflexes contribute to the pathophysiology of essential and/or obesity-induced hypertension may provide significant insights into improving antihypertensive therapeutic approaches.

Female Mice Exposed to Postnatal Neglect Display Angiotensin II-Dependent Obesity-Induced Hypertension.

Background We have previously reported that female mice exposed to maternal separation and early weaning (MSEW), a model of early life stress, show exacerbated diet-induced obesity associated with hypertension. The goal of this study was to test whether MSEW promotes angiotensin II-dependent hypertension via activation of the renin-angiotensin system in adipose tissue. Methods and Results MSEW was achieved by daily separations from the dam and weaning at postnatal day 17, while normally reared controls were weaned at postnatal day 21. Female controls and MSEW weanlings were placed on a low-fat diet (LF, 10% kcal from fat) or high-fat diet (HF, 60% kcal from fat) for 20 weeks. MSEW did not change mean arterial pressure in LF-fed mice but increased it in HF-fed mice compared with controls (P<0.05). In MSEW mice fed a HF, angiotensin II concentration in plasma and adipose tissue was elevated compared with controls (P<0.05). In addition, angiotensinogen concentration was increased solely in adipose tissue from MSEW mice (P<0.05), while angiotensin-converting enzyme protein expression and activity were similar between groups. Chronic enalapril treatment (2.5 mg/kg per day, drinking water, 7 days) reduced mean arterial pressure in both groups of mice fed a HF (P<0.05) and abolished the differences due to MSEW. Acute angiotensin II-induced increases in mean arterial pressure (10 µg/kg SC) were attenuated in untreated MSEW HF-fed mice compared to controls (P<0.05); however, this response was similar between groups in enalapril-treated mice. Conclusions The upregulation of angiotensinogen and angiotensin II in adipose tissue could be an important mechanism by which female MSEW mice fed a HF develop hypertension.

Cardiovascular and Metabolic Consequences of Testosterone Supplements in Young and Old Male Spontaneously Hypertensive Rats: Implications for Testosterone Supplements in Men.

BACKGROUND: The safety of testosterone supplements in men remains unclear. In the present study, we tested the hypothesis that in young and old male spontaneously hypertensive rats (SHR), long-term testosterone supplements increase blood pressure and that the mechanism is mediated in part by activation of the renin-angiotensin system. METHODS AND RESULTS: In untreated males, serum testosterone exhibited a sustained decrease after 5 months of age, reaching a nadir by 18 to 22 months of age. The reductions in serum testosterone were accompanied by an increase in body weight until very old age (18 months). Testosterone supplements were given for 6 weeks to young (12 weeks-YMSHR) and old (21-22 months-OMSHR) male SHR that increased serum testosterone by 2-fold in young males and by 4-fold in old males. Testosterone supplements decreased body weight, fat mass, lean mass, and plasma leptin, and increased plasma estradiol in YMSHR but had no effect in OMSHR. Mean arterial pressure (MAP) was significantly higher in OMSHR than in YMSHR and testosterone supplements decreased MAP in OMSHR, but significantly increased MAP in YMSHR. Enalapril, the angiotensin-converting enzyme inhibitor, reduced MAP in both control and testosterone-supplemented YMSHR, but had a greater effect on MAP in testosterone-treated rats, suggesting the mechanism responsible for the increase in MAP in YMSHR is mediated at least in part by activation of the renin-angiotensin system. CONCLUSIONS: Taken together with previous studies, these data suggest that testosterone supplements may have differential effects on men depending on age, cardiovascular and metabolic status, and dose and whether given long-term or short-term.

20-HETE and CYP4A2 ω-hydroxylase contribute to the elevated blood pressure in hyperandrogenemic female rats.

In male rats, androgen supplements increase 20-hydroxyeicosatetraenoic acid (20-HETE) via cytochrome P-450 (CYP)4A ω-hydroxylase and cause an increase in blood pressure (BP). In the present study, we determined the roles of 20-HETE and CYP4A2 on the elevated BP in hyperandrogenemic female rats. Chronic dihydrotestosterone (DHT) increased mean arterial pressure (MAP) in female Sprague-Dawley rats (96 ± 2 vs. 108 ± 2 mmHg, P < 0.05) and was associated with increased renal microvascular CYP4A2 mRNA expression (15-fold), endogenous renal 20-HETE (5-fold), and ω-hydroxylase activity (3-fold). Chronic DHT also increased MAP in low salt-fed Dahl salt-resistant female rats (81 ± 4 vs. 95 ± 1 mmHg, P < 0.05) but had no effect on MAP in Dahl salt-sensitive female rats (154 ± 3 vs. 153 ± 3 mmHg), which are known to be 20-HETE deficient. To test the role of CYP4A2, female CYP4A2(-/-) and SS.5(Bn) (wild type) rats were treated with DHT. DHT increased MAP in SS.5(Bn) female rats (104 ± 1 vs. 128 ± 1 mmHg, P < 0.05) but had no effect in CYP4A2(-/-) female rats (118 ± 1 vs. 120 ± 1 mmHg). Renal microvascular 20-HETE was reduced in control CYP4A2(-/-) female rats and was increased with DHT in SS.5(Bn) female rats (6-fold) but not CYP4A2(-/-) female rats. ω-Hydroxylase activity was 40% lower in control CYP4A2(-/-) female rats than in SS.5(Bn) female rats, and DHT decreased ω-hydroxylase activity in SS.5(Bn) female rats (by 50%) but significantly increased ω-hydroxylase activity in CYP4A2(-/-) female rats (3-fold). These data suggest that 20-HETE via CYP4A2 contributes to the elevation in BP in hyperandrogenemic female rats. The data also suggest that 20-HETE synthesis inhibition may be effective in treating the elevated BP in women with hyperandrogenemia, such as women with polycystic ovary syndrome.

Cardiometabolic Effects of Chronic Hyperandrogenemia in a New Model of Postmenopausal Polycystic Ovary Syndrome.

Postmenopausal women who have had polycystic ovary syndrome (PCOS) and chronic hyperandrogenemia may be at a greater risk for cardiovascular disease than normoandrogenemic postmenopausal women. The cardiometabolic effect of chronic hyperandrogenemia in women with PCOS after menopause is unclear. The present study was performed to test the hypothesis that chronic hyperandrogenemia in aging female rats would have more deleterious effects on metabolic function, blood pressure, and renal function than in normoandrogenemic age-matched females. Female Sprague Dawley were implanted continuously, beginning at 4-5 weeks, with dihydrotestosterone (postmenopausal hyperandrogenemic female [PMHAF]) or placebo pellets (controls), and were studied at 13 months of age. Plasma DHT was 3-fold higher, and estradiol was 90% lower in PMHAF than controls. Body weights were higher; EchoMRI showed greater fat and lean mass; and computed tomography showed more sc and visceral adiposity in PMHAF, but with similar femur length compared with controls. Insulin resistance was present in PMHAF with higher plasma insulin, normal fasting blood glucose, abnormal oral glucose tolerance test, and higher nonfasting blood glucose. Blood pressure (radiotelemetry) was significantly higher and heart rate was lower, and renal function (glomerular filtration rate) was reduced by 40% in PMHAF. Thus the aging chronically hyperandrogenemic female rat is a new model of postmenopausal PCOS, which exhibits insulin resistance and visceral obesity, hypertension, and impairment in renal function. This new model provides a unique tool to study the deleterious effects of chronic androgen excess in postmenopausal females rats.

Mapping brain Fos immunoreactivity in response to water deprivation and partial rehydration: Influence of sodium intake.

Water deprivation (WD) followed by water intake to satiety, produces satiation of thirst and partial rehydration (PR). Thus, WD-PR is a natural method to differentiate thirst from sodium appetite. WD-PR also produces Fos immunoreactivity (Fos-ir) in interconnected areas of a brain circuit postulated to subserve sodium appetite. In the present work, we evaluated the effect of sodium intake on Fos-ir produced by WD-PR in brain areas operationally defined according to the literature as either facilitatory or inhibitory to sodium intake. Isotonic NaCl was available for ingestion in a sodium appetite test performed immediately after a single episode of WD-PR. Sodium intake decreased Fos-ir in facilitatory areas such as the lamina terminalis (particularly subfornical organ and median preoptic nucleus), central amygdala and hypothalamic parvocellular paraventricular nucleus in the forebrain. Sodium intake also decreased Fos-ir in inhibitory areas such as the area postrema, lateral parabrachial nucleus and nucleus of the solitary tract in the hindbrain. In contrast, sodium intake further increased Fos-ir that was activated by water deprivation in the dorsal raphe nucleus, another inhibitory area localized in the hindbrain. WD-PR increased Fos-ir in the core and shell of the nucleus accumbens. Sodium intake reduced Fos-ir in both parts of the accumbens. In summary, sodium intake following WD-PR reduced Fos-ir in most facilitatory and inhibitory areas, but increased Fos-ir in another inhibitory area. It also reduced Fos-ir in a reward area (accumbens). The results suggest a functional link between sodium intake and the activity of the hindbrain-forebrain circuitry subserving reward and sodium appetite in response to water deprivation.

Serotonergic system involvement in the inhibitory action of estrogen on induced sodium appetite in female rats.

This study of the participation of the serotonergic system in the inhibitory effect of estrogen on induced sodium appetite in female rats explores sodium appetite induced by Furosemide and low sodium diet treatment (DEP) in normally cycling rats and in ovariectomized rats with and without estradiol replacement (OVX, OVX+E(2)). We also analyzed the neural activity of serotonergic neurons of the dorsal raphe nucleus (DRN) as well as the activity of other brain nuclei previously found to be involved in sodium and water balance in sodium depleted animals without access to the intake test. For this purpose, we examined the brain Fos, Fos-serotonin and Fos-vasopressin immunoreactivity patterns in diestrus (D), estrus (E), OVX and OVX+E(2) rats subjected to DEP. Female rats in E and OVX+E(2) exhibited a significant decrease in induced sodium intake compared with females in D and OVX. This estrogen-dependent inhibition on induced sodium appetite (approximately 50% reduction) can be correlated with changes in Fos activation observed in the organum vasculosum of the lamina terminalis (OVLT) and DRN, in response to sodium depletion. Given our previous observations in males, the expected sodium depletion-induced activity of the OVLT was found to be absent in OVX+E(2) females, while the usual inhibitory tonic activity of serotonergic neurons of the DRN, instead of decreasing after sodium depletion, increases or remains unchanged in OVX+E(2)-DEP and E-DEP females, respectively. Regarding urinary water and sodium excretion 3h after furosemide treatment, E-DEP and OVX+E(2)-DEP animals excreted smaller volumes of more highly concentrated urine than depleted D and OVX rats. Twenty hours after sodium depletion, the same groups of animals also showed a significant increase in the number of Fos-AVP immunoreactive neurons within the supraoptic nucleus, compared with D-DEP. In summary, our results demonstrate an estrogen-dependent inhibition of induced sodium appetite in normally cycling rats and ovariectomized animals with estradiol replacement, which may involve an interaction between excitatory neurons of the OVLT and inhibitory serotonergic cells of the DRN. The main finding is thus serotonergic system involvement as a possible mechanism in the inhibitory action of estrogen on induced sodium appetite.

Early maternal separation and chronic variable stress as adults differentially affect Fos expression in the anterodorsal thalami nuclei.

The present study examined the participation of the anterodorsal thalamic nuclei (ADTN) in mediating the long-term effects of early maternal separation on the stress/hypothalamic-pituitary-adrenal axis response of adult animals. The study measured Fos and glucocorticoid receptor immunoreactivity (GR-ir) in the ADTN of maternally separated female rats subsequently exposed to variable chronic stress. Maternal separation increased the number of neurons immunoreactive to Fos in the ADTN of chronically stressed adult rats. GR-ir was absent in the ADTN. Linking these results with previous endocrine evidence led the authors to propose a dual role of these nuclei. Maternal separation and chronic stress enhance the neuronal activity of the ADTN, nevertheless it is not regulated, at least directly, via GR.