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Context Salt sensitivity of blood pressure (SSBP) is associated with increased cardiovascular risk, especially in individuals of African descent, although the underlying mechanisms remain obscure. Lysine-specific demethylase 1 (LSD1) is a salt-sensitive epigenetic regulator associated with SSBP and aldosterone dysfunction. An LSD1 risk allele in humans is associated with SSBP and lower aldosterone levels in hypertensive individuals of African but not European descent. Heterozygous knockout LSD1 mice display SSBP and aldosterone dysregulation, but this effect is modified by age and biological sex. This might explain differences in cardiovascular risk with aging and biological sex in humans. Objective This work aims to determine if LSD1 risk allele (rs587618) carriers of African descent display a sex-by-age interaction with SSBP and aldosterone regulation. Methods We analyzed 297 individuals of African and European descent from the HyperPATH cohort. We performed multiple regression analyses for outcome variables related to SSBP and aldosterone. Results LSD1 risk allele carriers of African (but not European) descent had greater SSBP than nonrisk homozygotes. Female LSD1 risk allele carriers of African descent had greater SSBP, mainly relationship-driven by women with low estrogen (postmenopausal). There was a statistically significant LSD1 genotype-sex interaction in aldosterone response to angiotensin II stimulation in individuals aged 50 years or younger, with female carriers displaying decreased aldosterone responsiveness. Conclusion SSBP associated with LSD1 risk allele status is driven by women with a depleted estrogen state. Mechanisms related to a resistance to develop SSBP in females are uncertain but may relate to an estrogen-modulating effect on mineralocorticoid receptor (MR) activation and/or LSD1 epigenetic regulation of the MR.

Inconsistencies have been reported on the effect of sex on aldosterone (ALDO) levels leading to clinical confusion. The reasons for these inconsistencies are uncertain but include estrogen and/or its receptor modulating target gene responses to mineralocorticoid receptor activation and ALDO secretagogues’ levels. This study’s goal was to determine whether ALDO’s biosynthesis also differed by sex. Two approaches were used. First, plasma renin activity and aldosterone were measured in rats. Both were significantly higher in males. Secondly, using rat zona glomerulosa (ZG) cells, we assessed three ex vivo areas: (1) activity/levels of early steps in ALDO’s biosynthesis (StAR and CYP11A1); (2) activity/levels of a late step (CYP11B2); and (3) the status of the mineralocorticoid receptor (MR)-mediated, ultrashort feedback loop. Females had higher expression of CYP11A1 and StAR and increased CYP11A1 activity (increased pregnenolone/corticosterone levels) but did not differ in CYP11B2 expression or activity (ALDO levels). Activating the ZG’s MR (thereby activating the ultrashort feedback loop) reduced CYP11B2’s activity similarly in both sexes. Exvivo, these molecular effects were accompanied, in females, by lower ALDO basally but higher ALDO with angiotensin II stimulation. In conclusion, we documented that not only was there a sex-mediated difference in the activity of ALDO’s biosynthesis but also these differences at the molecular level help explain the variable reports on ALDO’s circulating levels. Basally, both in vivo and ex vivo, males had higher ALDO levels, likely secondary to higher ALDO secretagogue levels. However, in response to acute stimulation, ALDO levels are higher in females because of the greater levels and/or activity of their StAR/CYP11A1.

Biologic sex influences the development of cardiovascular disease and modifies aldosterone (ALDO) and blood pressure (BP) phenotypes: females secrete more ALDO, and their adrenal glomerulosa cell is more sensitive to stimulation. Lysine-specific demethylase 1 (LSD1) variants in Africans and LSD1 deficiency in mice are associated with BP and/or ALDO phenotypes. This study, in 18- and 40-week-old wild type (WT) and LSD1+/− mice, was designed to determine whether (1) sex modifies ALDO biosynthetic enzymes; (2) LSD1 deficiency disrupts the effect of sex on these enzymes; (3) within each genotype, there is a positive relationship between ALDO biosynthesis (proximate phenotype), plasma ALDO (intermediate phenotype) and BP levels (distant phenotype); and (4) sex and LSD1 genotype interact on these phenotypes. In WT mice, female sex increases the expression of early enzymes in ALDO biosynthesis but not ALDO levels or systolic blood pressure (SBP). However, enzyme expressions are shifted downward in LSD1+/− females vs males, so that early enzyme levels are similar but the late enzymes are substantially lower. In both age groups, LSD1 deficiency modifies the adrenal enzyme expressions, circulating ALDO levels, and SBP in a sex-specific manner. Finally, significant sex/LSD1 genotype interactions modulate the three phenotypes in mice. In conclusion, biologic sex in mice interacts with LSD1 deficiency to modify several phenotypes: (1) proximal (ALDO biosynthetic enzymes); (2) intermediate (circulating ALDO); and (3) distant (SBP). These results provide entry to better understand the roles of biological sex and LSD1 in (1) hypertension heterogeneity and (2) providing more personalized treatment.

In humans, caveolin-1 (cav-1) gene polymorphisms confer a metabolic syndrome (MetS) phenotype and higher aldosterone (Aldo) levels. Further, global cav-1 knock out (KO) mice recapitulate the MetS phenotype, with both cardiovascular (CV) and metabolic dysfunction. We have shown that vascular dysfunction in the cav-1 KO is dissociated from the metabolic phenotype and is mediated by an endothelial crosstalk between cav-1 and the Aldo-mineralocorticoid receptor (MR) signaling pathway. Hence, we hypothesized endothelial cav-1 deficiency in mice is a major contributor to CV (but not metabolic) dysfunction.To assess this hypothesis, we generated Tie-2 mediated endothelium-specific cav-1 KO (ECKO) and appropriate genetic wild type (WT) control mice and studied their metabolic and CV traits in response to 1) changes in dietary salt intake (0.03% (LS) vs. 1.6% Na + (HS)) and 2) 3-weeks of Aldo infusion (200μg/kg/day) during sodium loading. Our results showed no difference in glucose, lipids and HOMA-IR in ECKO vs. WT mice, irrespective of the dietary intervention. However, on a HS (but not a LS) diet, ECKO vs. WT mice displayed similar CV dysfunction as previously shown in the full cav-1 KO: increased Aldo levels (73.7±11.1 vs 47.8±4.7ng/dl, p

Aldosterone modulates the activity of both epithelial (specifically renal) and non-epithelial cells. Binding to the mineralocorticoid receptor (MR), activates two pathways: the classical genomic and the rapidly activated non-genomic that is substantially modulated by the level of striatin. We hypothesized that disruption of MR’s non-genomic pathway would alter aldosterone-induced cardiovascular/renal damage. To test this hypothesis, wild type (WT) and striatin heterozygous knockout (Strn+/−) littermate male mice were fed a liberal sodium (1.6% Na+) diet and randomized to either protocol one: 3 weeks of treatment with either vehicle or aldosterone plus/minus MR antagonists, eplerenone or esaxerenone or protocol two: 2 weeks of treatment with either vehicle or L-NAME/AngII plus/minus MR antagonists, spironolactone or esaxerenone. Compared to the WT mice, basally, the Strn+/− mice had greater (~26%) estimated renal glomeruli volume and reduced non-genomic second messenger signaling (pAkt/Akt ratio) in kidney tissue. In response to active treatment, the striatin-associated-cardiovascular/renal damage was limited to volume effects induced by aldosterone infusion: significantly increased blood pressure (BP) and albuminuria. In contrast, with aldosterone or L-NAME/AngII treatment, striatin deficiency did not modify aldosterone-mediated damage: in the heart and kidney, macrophage infiltration, and increases in aldosterone-induced biomarkers of injury. All changes were near-normalized following MR blockade with spironolactone or esaxerenone, except increased BP in the L-NAME/AngII model. In conclusion, the loss of striatin amplified aldosterone-induced damage suggesting that aldosterone’s non-genomic pathway is protective but only related to effects likely mediated via epithelial, but not non-epithelial cells.

LSD1 (lysine-specific demethylase-1) is an epigenetic regulator of gene transcription. LSD1 risk allele in humans and LSD1 deficiency ( LSD1 +/− ) in mice confer increasing salt-sensitivity of blood pressure with age, which evolves into salt-sensitive hypertension in older individuals. However, the mechanism underlying the relationship between LSD1 and salt-sensitivity of blood pressure remains elusive. Here, we show that LSD1 genotype (in humans) and LSD1 deficiency (in mice) lead to similar associations with increased blood pressure and urine potassium levels but with decreased aldosterone levels during a liberal salt diet. Thus, we hypothesized that LSD1 deficiency leads to an MR (mineralocorticoid receptor)-dependent hypertensive state. Yet, further studies in LSD1 +/− mice treated with the MR antagonist eplerenone demonstrate that hypertension, kaliuria, and albuminuria are substantially improved, suggesting that the ligand-independent activation of the MR is the underlying cause of this LSD1 deficiency–mediated phenotype. Indeed, while MR and epithelial sodium channel expression levels were increased in LSD1 +/− mouse kidney tissues, aldosterone secretion from LSD1 +/− glomerulosa cells was significantly lower. Collectively, these data establish that LSD1 deficiency leads to an inappropriate activation and increased levels of the MR during a liberal salt regimen and suggest that inhibiting the MR pathway is a useful strategy for treatment of hypertension in human LSD1 risk allele carriers.

There are conflicting data on whether variations of physiologic cortisol levels associated with cardiovascular risk. We hypothesize that prior discordant findings are related to problems associated with varying sample size, techniques for assessing cardiovascular risk and failure to adequately account for environmental factors. To address these issues, we utilized a large sample size, selected the Framingham risk score to compute cardiovascular risk and performed the study in a highly controlled setting. We had two main objectives: determine whether higher, yet physiologic, cortisol levels associated with increased cardiovascular risk and determine whether caveolin-1 (rs926198) risk allele carriers associated with increased cardiovascular risk. This was a cross-sectional study of 574 non-diabetic individuals who completed a common protocol. Data collection included fasting blood samples, blood pressure measurements and a 24-h urine-free cortisol collection. Five hundred seventeen of these participants also completed caveolin-1 genotyping. Subjects were classified as belonging to either the low-mode or high-mode urine-free cortisol groups, based on the bimodal distribution of urine-free cortisol. In multivariate analysis, Framingham risk score was statistically higher in the high-mode cortisol group (10.22 (mean) ± 0.43 (s.e.m.)) compared to the low-mode cortisol group (7.73 ± 0.34), P P = 0.034. Overall, the estimated effect on Framingham risk score of carrying the caveolin-1 risk allele was 1.33 ± 0.61, P = 0.029. Both urinary cortisol and caveolin-1 risk allele status are independent predictors of Framingham risk score.

Both mechanistic target of rapamycin (mTOR) pathway and aldosterone are implicated in the development of cardiovascular and renal disease. However, the interaction between aldosterone and the mTOR pathway is unknown. We hypothesized the following: that (i) increased aldosterone will modulate the activity of the mTORC1 and mTORC2 molecular pathways in the heart and kidney; (ii) a physiologic increase in aldosterone will affect these pathways differently than a pathophysiologic one; and (iii) the changes in the mTOR level/activity will differ between the heart and kidney. In both kidney and heart tissues, phosphorylation of mTOR is significantly decreased when aldosterone levels are physiologically increased (by dietary sodium restriction), followed by a decrease in phosphorylated p70S6K1 in cardiac, but not renal, tissue. Sirtuin 1, an epigenetic modulator, is decreased in the heart but increased in the kidney. Conversely, pathophysiologic aldosterone levels (an infusion for 3 weeks) had divergent effects on phosphorylated mTOR and the downstream substrates of mTORC1 and mTORC2 in cardiac and renal tissues. Increased aldosterone levels significantly alter mTOR activity in the heart and kidney. In the kidney, substantial differences were noted if the increase was produced physiologically vs pathophysiologically, suggesting that mTOR activity, in part, may mediate aldosterone-induced renal damage. Thus, modulating mTOR activity may reduce aldosterone-dependent renal damage similar to mineralocorticoid receptor blockade but potentially with less adverse side effects.

Statin use is associated with lower aldosterone levels. We hypothesized that caveolin-1 may be important for the uptake of statins into the adrenal gland and would affect statin’s aldosterone-lowering effects. The aim of this study was to test whether the caveolin-1 risk allele (rs926198) would affect aldosterone levels associated with statin use. The Hypertensive Pathotype database includes healthy and hypertensive individuals who have undergone assessment of adrenal hormones. Individuals were studied off antihypertensive medications but were maintained on statins if prescribed by their personal physician. Adrenal hormones were measured at baseline and after 1 hour of angiotensin II stimulation on both high- and low-sodium diets. A mixed-model repeated-measures analysis was employed with a priori selected covariates of age, sex, body mass index, and protocol (low versus high sodium, baseline versus angiotensin II stimulated aldosterone). A total of 250 individuals were included in the study; 31 individuals were taking statins (12.4%) and 219 were not. Among statin users, carrying a caveolin-1 risk allele resulted in a 25% (95% CI, 1–43.2) lower aldosterone level ( P =0.04). However, among nonstatin users, carrying a caveolin-1 risk allele resulted in no significant effect on aldosterone levels ( P =0.38). Additionally, the interaction between caveolin-1 risk allele and statin use on aldosterone levels was significant ( P =0.03). These findings suggest caveolin-1 risk allele carrying individuals are likely to receive the most benefit from statin’s aldosterone-lowering properties; however, due to the observational nature of this study, these findings need further investigation.

Background: Hypertension (HT) is a well-established independent risk factor for adverse cardiovascular and renal (CVR) outcomes and a high salt (HS) diet is the main cause for high blood pressure (BP). Despite extensive research focusing on HT, surprisingly there are no longitudinal studies assessing the long-term effects of HS. Aims: This study aimed (1) to evaluate the timing of onset for changes in CVR health during long-term sodium loading and (2) to assess whether salt restriction can prevent these effects. Methods: C57BL/6 mice were randomized to HS, moderate (NS) or low (LS) salt diet and followed longitudinally for 50 weeks (wks). BP, urinary albumin/creatinine ratio (AC), plasma aldosterone (PA) and renin activity (PRA) were assessed monthly. At the end of the study, renal artery resistance and left ventricular (LV) parameters were measured by ultrasound and echocardiogram. Renal AT1 expression (Western Blot) and activity (IHQ) were quantified. Results: At the beginning of the study, there were no differences in BP and AC between the three dietary groups. Relative to wk 1, BP (mmHg) in the HS group was higher in wk 21 (131±1.7 vs. 115±3.0, p= 0.05). Sodium restriction delayed this increase: SBP was higher in wk 41 in the NS group compared to the wk 1 (128±3.4 vs. 115±6.4, p= 0.05) but did not reach significance in the LS group until the end of the study. Similarly, relative to wk 1, AC (µg/mg) only in the HS group reached significantly higher levels in wk 17 (44±4.2, p

Background : The β2-adrenergic receptor (β2-AR) has been implicated in blood pressure (BP) homeostasis via its effects on the sympathetic nervous system, cardiac function, peripheral vascular resistance, and renin release. We also have documented that a β2-AR diplotype (Arg16/Gln27), carried by 15% of hypertensives, have salt sensitive hypertension (SSBP) and increased aldosterone (ALDO). Gap in knowledge: it has been reported that hypertensive men and women respond differently to beta blockers. However, information regarding sex differences in carriers of the β2-AR risk diplotype is limited. Hypothesis : In mice, the phenotype in female carriers of the mutant β2-AR risk diplotype will differ from male carriers. Methods: The CRISPR/Cas9 approach was used to generate transgenic mice carrying 0, 1 or 2 Arg16/Gln27 variant alleles (i.e. wild-type (WT), heterozygous (Het) or mutant (Mut)). The experimental design included twelve weeks old mice divided into 6 genotype/gender groups (male and female; WT, Het and Mut) maintained on low (0.03% Na+, LS) and high sodium diets (1.6% Na+, HS) for a week each. Results: 1) Both male and female mice displayed significantly increased BP on LS and HS with increasing number of mutated alleles. 2) Only Mut females displayed SSBP (P 3) As compared to WT, urine and plasma ALDO levels were lower in male (but not female) carriers of the mutated allele (P 4) As anticipated, urine K+ excretion was significantly lower in the Mut male (but not female) mice (P 5) Doppler ultrasound measurements of renovascular function shows that the resistive index was significantly lower in Mut vs WT males (P 6) β2-AR expression was significantly lower in female vs. male WT mice; however, this difference was lost in the carriers of the mutated allele, as B2-AR expression levels were significantly higher in female carriers of the mutated allele, as compared to WT (P Conclusion: Both male and female Mut animals have increased BP compared to WT mice, but the mechanisms underlying their increased BP differ by sex. Female Mut mice have SSBP, inappropriately non-suppressed ALDO and decreased RBF. Male Mut mice do not have SSBP and have appropriate ALDO and RBF response to the salt load.

The mechanistic target of the rapamycin (mTOR) pathway plays a role in features common to both excess salt/aldosterone and cardiovascular/renal diseases. Dietary sodium can upregulate mTORC1 signaling in cardiac and renal tissue, and the inhibition of mTOR can prevent aldosterone-associated, salt-induced hypertension. The impact of sex and age on mTOR’s role in volume homeostasis and the regulation of aldosterone secretion is largely unknown. We hypothesize that both age and sex modify mTOR’s interaction with volume homeostatic mechanisms. The activity of 3 volume homeostatic mechanisms—cardiovascular, renal, and hormonal (aldosterone [sodium retaining] and brain natriuretic peptide [BNP; sodium losing])—were assessed in mTORC1 deficient (Raptor +/-) and wild-type male and female littermates at 2 different ages. The mice were volume stressed by being given a liberal salt (LibS) diet. Raptor +/-mice of both sexes when they aged: (1) reduced their blood pressure, (2) increased left ventricular internal diameter during diastole, (3) decreased renal blood flow, and (4) increased mineralocorticoid receptor expression. Aldosterone levels did not differ by sex in young Raptor +/- mice. However, as they aged, compared to their littermates, aldosterone decreased in males but increased in females. Finally, given the level of Na+ intake, BNP was inappropriately suppressed, but only in Raptor +/- males. These data indicate that Raptor +/- mice, when stressed with a LibS diet, display inappropriate volume homeostatic responses, particularly with aging, and the mechanisms altered, differing by sex.

We posit the existence of a paracrine/autocrine negative feedback loop, mediated by the mineralocorticoid receptor (MR), regulating aldosterone secretion. To assess this hypothesis, we asked whether altering MR activity in zona glomerulosa (ZG) cells affects aldosterone production. To this end, we studiedex vivoZG cells isolated from male Wistar rats fed chow containing either high (1.6% Na+(HS)) or low (0.03% Na+(LS)) amount of sodium. Western blot analyses demonstrated that MR was present in both the ZG and zona fasciculata/zona reticularis (ZF/ZR/ZR). In ZG cells isolated from rats on LS chow, MR activation by fludrocortisone produced a 20% and 60% reduction in aldosterone secretion basally and in response to angiotensin II (ANGII) stimulation, respectively. Corticosterone secretion was increased in these cells suggesting that aldosterone synthase activity was being reduced by fludrocortisone. In contrast, canrenoic acid, an MR antagonist, enhanced aldosterone production by up to 30% both basally and in response to ANGII. Similar responses were observed in ZG cells from rats fed HS. Modulating glucocorticoid receptor (GR) activity did not alter aldosterone production by ZG cells; however, altering GR activity did modify corticosterone production from ZF/ZR/ZR cells both basally and in response to adrenocorticotropic hormone (ACTH). Additionally, activating the MR in ZF/ZR/ZR cells strikingly reduced corticosterone secretion. In summary, these data support the hypothesis that negative ultra-short feedback loops regulate adrenal steroidogenesis. In the ZG, aldosterone secretion is regulated by the MR, but not the GR, an effect that appears to be secondary to a change in aldosterone synthase activity.

The beta-2 adrenergic receptor (B2AR) is an established regulator of vascular tone and cardiac contractility. Two polymorphisms of the B2AR (Gly16Arg and Glu27Gln) have been associated with cardiovascular phenotypes, including hypertension, salt sensitivity of BP, cardiovascular disease and responses to antihypertensives. These same variants are associated with changes in receptor downregulation and desensitization in pulmonary tissues; however, there is no information on the effect of these polymorphisms on B2AR expression/function in cardiovascular tissues. To investigate the effect of these variants on cardiovascular function, we used the CRISPR/Cas9 approach to generate transgenic mice that carry the diplotype Arg16/Gln27 on 2, 1 or 0 alleles, i. e. mutant (Mut), heterozygous (Het) and wild-type (WT). Both male and female mice displayed significantly higher body weights with the increase in number of mutated alleles (P

Salt sensitivity of blood pressure (SSBP) and hypertension are common, but the underlying mechanisms remain unclear. Endoplasmic reticulum aminopeptidase 1 (ERAP1) degrades angiotensin II (ANGII). We hypothesized that decreasing ERAP1 increases BP via ANGII-mediated effects on aldosterone (ALDO) production and/or renovascular function. Compared with WT littermate mice, ERAP1-deficient (ERAP1+/-) mice had increased tissue ANGII, systolic and diastolic BP, and SSBP, indicating that ERAP1 deficiency leads to volume expansion. However, the mechanisms underlying the volume expansion differed according to sex. Male ERAP1+/- mice had increased ALDO levels and normal renovascular responses to volume expansion (decreased resistive and pulsatility indices and increased glomerular volume). In contrast, female ERAP1+/- mice had normal ALDO levels but lacked normal renovascular responses. In humans, ERAP1 rs30187, a loss-of-function gene variant that reduces ANGII degradation in vitro, is associated with hypertension. In our cohort from the Hypertensive Pathotype (HyperPATH) Consortium, there was a significant dose-response association between rs30187 risk alleles and systolic and diastolic BP as well as renal plasma flow in men, but not in women. Thus, lowering ERAP1 led to volume expansion and increased BP. In males, the volume expansion was due to elevated ALDO with normal renovascular function, whereas in females the volume expansion was due to impaired renovascular function with normal ALDO levels.

Statin therapy, which lowers LDL cholesterol, has a profound beneficial cardiovascular (CV) effect. However, some of statins’ CV benefits appear to be independent of decreases in LDL. We showed that statins reduce Aldosterone (ALDO) levels, a key hormone in cardiovascular function, and this effect was greater in lipophilic (e.g., Simvastatin) versus hydrophilic (e.g., Pravastatin) statins. The mechanism by which statins reduce ALDO production is unknown. Thus, the purpose of this study was to determine the effects of statins on the two key regulatory steps of ALDO biosynthesis. We hypothesized that Simvastatin, but not pravastatin, would inhibit the late, but not the early pathway of ALDO biosynthesis. Methods: Wistar rats (n=80, 30% female, 175-250 grams) were fed a 0.03% Na+ diet for 7 days with ad lib access to tap water. After euthanasia Zona Glomerulosa (ZG) cells were isolated from adrenal capsules. ZG cell incubates were studied for 1 hour under the following 8 conditions; Control, Angiotensin II (AngII, 10-7M), Fludrocortisone acetate (Fludro, 3µg), Simvastatin (SIMV, 100µM), Pravastatin (PRAV,100µM), Fludro+AngII, SIMV+AngII, and PRAV+AngII. To separately evaluate the early and late pathways we added Trilostane (TRIL), which inhibits 3β-OH-dehydrogenase enzyme, and a fixed dose of Corticosterone (CORT, 1µM) to the ZG cells. Under these conditions, Pregnenolone levels (PREG reflect early pathway activity and the ALDO/Corticosterone (ALDO/CORT) ratios reflect late pathway activity. Cells in each of the 8 conditions were incubated with and without TRIL (10µM) plus CORT, replicated in duplicate, and repeated 8 times. Results in ALDO and ALDO/CORT Ratio are presented as percent of maximum response (obtained after stimulation with AngII or in control conditions) while other data are in absolute measures, and analyzed by ANOVA and t-test. Results: In comparison to the maximum response caused by AngII (without TRIL); SIMV caused a reduction in aldosterone production while PRAV did not (72.1±26.6% vs 105±32.1%, p < 0.05). In the presence of TRIL, we observed that; 1) SIMV increased PREG in comparison to the control (696.63±98.15ng/dL vs 286.95±167.82ng/dL, p < 0.05) and to PRAV (696.63±98.15ng/dL vs. 291.57±290.39ng/dL, p < 0.05). However, 2) SIMV reduced the Aldo/Cort Ratio when compared to the Control, AngII, and Pravastatin conditions (53.3±5.3% vs 100%, 95.1±8.2%, 81.3±12.0%, p < 0.05 for SIMV vs all other conditions). Conclusions: These data show that SIMV and not PRAV decreases ALDO production. SIMV reduces ALDO by inhibiting the late pathway of ALDO biosynthesis. The SIMV-induced increase in PREG, is insufficient to overcome SIMV’s inhibition of the late pathway. These findings suggest that lipophilic statins have additional benefits (beyond HMG-CoA reductase inhibition) that influence the Renin-Angiotensin-Aldosterone System.

Context: There is conflicting data on whether variations of physiologic cortisol levels associate with cardiovascular (CV) risk. Objective: We sought to reconcile prior discordant findings through utilization of a large sample size and selection of Framingham risk score to assess cardiovascular risk. An additional objective was to assess the relationship between caveolin-1 (CAV1) risk allele, cortisol levels, and CV risk given that CAV1 risk allele carriers have been associated with increased CV risk. Design & Participants: This was a cross-sectional study of 574 non-diabetic individuals who completed a common protocol that controlled for environmental factors. Data collection included fasting blood samples, blood pressure measurements, and a 24-hour urine free cortisol (UFC) collection. 517 of these participants also completed CAV1 genotyping. Main Outcome Measure: Subjects were classified as belonging to either the low-mode or high-mode urine cortisol groups, based on the bimodal distribution of UFC. Framingham risk score was selected as the main outcome measure to assess composite cardiovascular risk. Results: Framingham risk score was statistically higher in the high-mode cortisol group (10.22 ± 5.12) compared to the low-mode cortisol group (7.73 ± 7.08), p-value < 0.001. Framingham risk score was also statistically higher in the CAV1 risk allele carriers (8.91 ± 6.51) compared to CAV1 non-risk allele carriers (7.59 ± 6.88), p-value 0.034. Overall, the estimated effect of the risk allele was 1.33 ± 0.61, p-value 0.029. Conclusions: Higher, yet physiologic, levels of urinary cortisol are associated with increased cardiovascular risk.

Lysine-specific demethylase-1 (LSD1) is a histone demethylase that mediates epigenetic regulation of gene transcription. We have shown that human risk allele carriers of a LSD1 variant as well as a LSD1 heterozygous knockout mice (LSD1+/-) have salt sensitive hypertension (HTN), but low aldosterone (ALDO) and plasma renin activity (PRA) levels. However, in young mice ALDO levels are inappropriately increased for the level of salt intake. Thus, we hypothesize that despite the low ALDO levels, the salt sensitive HTN is mineralocorticoid mediated secondary to an overactive mineralocorticoid receptor(MR). To test our hypothesis, wild-type (LSD1+/+) and LSD1+/- mice were fed a liberal sodium (1.6% Na+) diet for 7 days and were then randomized to placebo or eplerenone (Epl) treatment for 2 weeks. Systolic blood pressures (SBP) were measured before and after the intervention; albumin/creatinine ratios (A/C), plasma ALDO, as well as urine ALDO, sodium and potassium were measured at the end of the study. Results: Compared with LSD1+/+, LSD1+/- mice displayed higher SBP at the beginning of the study (132 ± 2.6 mmHg vs 113.8 ± 2.0 mmHg; P

Human risk allele carriers of lysine-specific demethylase 1 (LSD1) and LSD1-deficient mice have salt-sensitive hypertension for unclear reasons. We hypothesized that LSD1 deficiency causes dysregulation of aldosterone’s response to salt intake resulting in increased cardiovascular risk factors (blood pressure and microalbumin). Furthermore, we determined the effect of biological sex on these potential abnormalities. To test our hypotheses, LSD1 male and female heterozygote-knockout (LSD1+/−) and WT mice were assigned to two age groups: 18 weeks and 36 weeks. Plasma aldosterone levels and aldosterone production from zona glomerulosa cells studied ex vivo were greater in both male and female LSD1+/− mice consuming a liberal salt diet as compared to WT mice consuming the same diet. However, salt-sensitive blood pressure elevation and increased microalbuminuria were only observed in male LSD1+/− mice. These data suggest that LSD1 interacts with aldosterone’s secretory response to salt intake. Lack of LSD1 causes inappropriate aldosterone production on a liberal salt diet; males appear to be more sensitive to this aldosterone increase as males, but not females, develop salt sensitivity of blood pressure and increased microalbuminuria. The mechanism responsible for the cardiovascular protective effect in females is uncertain but may be related to estrogen modulating the effect of mineralocorticoid receptor activation.

The relationship between biological sex and aldosterone on blood pressure (BP) is unclear. We hypothesized that sex would modify the interaction between aldosterone and vascular responses to salt intake and angiotensin II (AngII). To test this hypothesis, in 1592 subjects from the well-controlled Hypertensive Pathotype cohort, we compared responses of women and men to chronic (BP and aldosterone levels in response to dietary salt) and acute (BP, renal plasma flow, and aldosterone responses to AngII infusion) manipulations. Women had a 30% higher salt sensitivity of BP than men ( P P P =0.003) between sex and aldosterone on BP response to AngII. Women also had a greater ( P P P P P

Over the last decades, our conventional understanding of aldosterone biosynthesis and signaling has been dramatically challenged. We learned that a local regulatory system modifies tissue levels of cortisol to improve aldosterone selectivity for the mineralocorticoid receptor (MR) and that steroid receptor signaling includes rapid nongenomic effects. Moreover, the MR has been identified in a wide variety of tissues beyond epithelial cells, which includes endothelial cells, vascular smooth muscle cells, fibroblasts, adipocytes, and myocytes. The function of aldosterone in these cells is different from the classic renal actions and could be explained by different signaling mechanisms and/or tissue-specific modulators. Likewise, aldosterone not only works through a classic nuclear receptor but also through a cell-surface receptor that regulate diverse intracellular events. By improving our understanding of MR signaling we have reshaped our vision of aldosterone beyond its classic role in electrolyte regulation to include newly discovered roles of MR in extrarenal tissues and a potential pathogenic role in cardiometabolic disorders.

Striatin is a protein regulator of vesicular trafficking in neurons that also binds caveolin-1 and Ca 2+ -calmodulin and could activate endothelial nitric oxide synthase. We have shown that striatin colocalizes with the mineralocorticoid receptor and that mineralocorticoid receptor activation increases striatin levels in vascular cells. To test whether striatin is a regulator of vascular function, wild-type and heterozygous striatin-deficient mice (Strn +/− ) were randomized in crossover intervention to restricted (0.03%) and liberal sodium (1.6%) diets for 7 days on each diet, and blood pressure and aortic vascular function were measured. Compared with wild-type, sodium restriction significantly reduced blood pressure in Strn +/− . On liberal salt intake, phenylephrine and high KCl caused a greater vascular contraction in Strn +/− than wild-type, and endothelium removal, nitric oxide synthase inhibitor L-NAME, and guanylate cyclase inhibitor ODQ enhanced phenylephrine contraction to a smaller extent in Strn +/− than wild-type. On liberal salt, acetylcholine relaxation was less in Strn +/− than in wild-type, and endothelium removal, L-NAME, and ODQ blocked acetylcholine relaxation, suggesting changes in endothelial NO-cGMP. On liberal salt, endothelial nitric oxide synthase mRNA expression and the ratio of endothelial nitric oxide synthase activator pAkt/total Akt were decreased in Strn +/− versus wild-type. Vascular relaxation to NO donor sodium nitroprusside was not different among groups. Thus, striatin deficiency is associated with salt sensitivity of blood pressure, enhanced vasoconstriction, and decreased vascular relaxation, suggesting a critical role for striatin, through modulation of endothelial NO-cGMP, in regulation of vascular function and BP during changes in sodium intake.

Aldosterone interacts with mineralocorticoid receptor (MR) to stimulate sodium reabsorption in renal tubules and may also affect the vasculature. Caveolin-1 (cav-1), an anchoring protein in plasmalemmal caveolae, binds steroid receptors and also endothelial nitric oxide synthase, thus limiting its translocation and activation. To test for potential MR/cav-1 interaction in the vasculature, we investigated if MR blockade in cav-1-replete or -deficient states would alter vascular function in a mouse model of low nitric oxide (NO)-high angiotensin II (AngII)-induced cardiovascular injury. Wild-type (WT) and cav-1 knockout mice (cav-1(-/-)) consuming a high salt diet (4% NaCl) received Nω-nitro-l-arginine methyl ester (L-NAME) (0.1-0.2 mg/ml in drinking water at days 1-11) plus AngII (0.7-2.8 mg/kg per day via an osmotic minipump at days 8-11) ± MR antagonist eplerenone (EPL) 100 mg/kg per day in food. In both genotypes, blood pressure increased with L-NAME + AngII. EPL minimally changed blood pressure, although its dose was sufficient to block MR and reverse cardiac expression of the injury markers cluster of differentiation 68 and plasminogen activator inhibitor-1 in L-NAME+AngII treated mice. In aortic rings, phenylephrine and KCl contraction was enhanced with EPL in L-NAME+AngII treated WT mice, but not cav-1(-/-) mice. AngII-induced contraction was not different, and angiotensin type 1 receptor expression was reduced in L-NAME + AngII treated WT and cav-1(-/-) mice. In WT mice, acetylcholine-induced relaxation was enhanced with L-NAME + AngII treatment and reversed with EPL. Acetylcholine relaxation in cav-1(-/-) mice was greater than in WT mice, not modified by L-NAME + AngII or EPL, and blocked by ex vivo L-NAME, 1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one (ODQ), or endothelium removal, suggesting the role of NO-cGMP. Cardiac endothelial NO synthase was increased in cav-1(-/-) versus WT mice, further increased with L-NAME + AngII, and not affected by EPL. Vascular relaxation to the NO donor sodium nitroprusside was increased with L-NAME + AngII in WT mice but not in cav-1(-/-) mice. Plasma aldosterone levels increased and cardiac MR expression decreased in L-NAME + AngII treated WT and cav-1(-/-) mice and did not change with EPL. Thus, during L-NAME + AngII induced hypertension, MR blockade increases contraction and alters vascular relaxation via NO-cGMP, and these changes are absent in cav-1 deficiency states. The data suggest a cooperative role of MR and cav-1 in regulating vascular contraction and NO-cGMP-mediated relaxation during low NO-high AngII-dependent cardiovascular injury.

Striatin is a novel protein that interacts with steroid receptors and modifies rapid, nongenomic activity in vitro. We tested the hypothesis that striatin would in turn affect mineralocorticoid receptor function and consequently sodium, water, and blood pressure homeostasis in an animal model. We evaluated salt sensitivity of blood pressure in novel striatin heterozygote knockout mice. Compared with wild type, striatin heterozygote exhibited a significant increase in blood pressure when sodium intake was increased from restricted (0.03%) to liberal (1.6%) sodium. Furthermore, renal expression of mineralocorticoid receptor and its genomic downstream targets serum/glucocorticoid-regulated kinase 1, and epithelial sodium channel was increased in striatin heterozygote versus wild-type mice on liberal sodium intake while the pAkt/Akt ratio, readout of mineralocorticoid receptor’s rapid, nongenomic pathway, was reduced. To determine the potential clinical relevance of these findings, we tested the association between single nucleotide polymorphic variants of striatin gene and salt sensitivity of blood pressure in 366 white hypertensive subjects. HapMap-derived tagging single nucleotide polymorphisms identified an association of rs2540923 with salt sensitivity of blood pressure (odds ratio, 6.25; 95% confidence interval, 1.7–20; P =0.01). These data provide the first in vivo evidence in humans and rodents that associates striatin with markers of mineralocorticoid receptor activity. The data also support the hypothesis that the rapid, nongenomic mineralocorticoid receptor pathway (mediated via striatin) has a role in modulating the interaction between salt intake and blood pressure.

Author(s): Manosroi, Worapaka; Tan, Jia Wei; Rariy, Chevon M; Sun, Bei; Goodarzi, Mark O; Saxena, Aditi R; Williams, Jonathan S; Pojoga, Luminita H; Lasky-Su, Jessica; Cui, Jinrui; Guo, Xiuqing; Taylor, Kent D; Chen, Yii-Der I; Xiang, Anny H; Hsueh, Willa A; Raffel, Leslie J; Buchanan, Thomas A; Rotter, Jerome I; Williams, Gordon H; Seely, Ellen W | Abstract: ContextHypertension in young women is uncommon compared with young men and older women. Estrogen appears to protect most women against hypertension, with incidence increasing after menopause. Because some premenopausal women develop hypertension, estrogen may play a different role in these women. Genetic variations in the estrogen receptor (ER) are associated with cardiovascular disease. ER-β, encoded by ESR2, is the ER predominantly expressed in vascular smooth muscle.ObjectiveTo determine an association of single nucleotide polymorphisms in ESR2 with salt sensitivity of blood pressure (SSBP) and estrogen status in women.MethodsCandidate gene association study with ESR2 and SSBP conducted in normotensive and hypertensive women and men in two cohorts: International Hypertensive Pathotype (HyperPATH) (n = 584) (discovery) and Mexican American Hypertension-Insulin Resistance Study (n = 662) (validation). Single nucleotide polymorphisms in ESR1 (ER-α) were also analyzed. Analysis conducted in younger (l51 years, premenopausal, "estrogen-replete") and older women (≥51 years, postmenopausal, "estrogen-deplete"). Men were analyzed to control for aging.ResultsMultivariate analyses of HyperPATH data between variants of ESR2 and SSBP documented that ESR2 rs10144225 minor (risk) allele carriers had a significantly positive association with SSBP driven by estrogen-replete women (β = +4.4 mm Hg per risk allele, P = 0.004). Findings were confirmed in Hypertension Insulin-Resistance Study premenopausal women. HyperPATH cohort analyses revealed risk allele carriers vs noncarriers had increased aldosterone/renin ratios. No associations were detected with ESR1.ConclusionsThe variation at rs10144225 in ESR2 was associated with SSBP in premenopausal women (estrogen-replete) and not in men or postmenopausal women (estrogen-deplete). Inappropriate aldosterone levels on a liberal salt diet may mediate the SSBP.

Background We hypothesized that caloric restriction ( CR ) and salt restriction (ResS) would have similar effects on reducing cardiovascular risk markers and that combining CR and ResS would be synergistic in modulating these markers. Methods and Results To test our hypothesis, rats were randomized into 2 groups: ad libitum liberal salt diet (ad libitum/high‐sodium, 1.6% sodium) or ResS diet (ad libitum/ResS, 0.03% sodium). CR was initiated in half of the rats in each group by reducing caloric intake to 60% while maintaining sodium intake constant ( CR /high‐sodium, 2.7% sodium or CR /ResS, 0.05% sodium) for 4 weeks. CR in rats on a high‐sodium diet improved metabolic parameters, renal transforming growth factor‐β and collagen‐1α1 and increased plasma adiponectin and renal visfatin and NAD + protein levels. Although CR produced some beneficial cardiovascular effects (increased sodium excretion and reduced blood pressure), it also was associated with potentially adverse cardiovascular effects. Adrenal zona glomerulosa cell responsiveness and aldosterone levels and activation were inappropriately increased for the volume state of the rodent. Like CR on HS , CR on a ResS diet also produced relative increased zona glomerulosa responsiveness and an increased blood pressure with no improvement in metabolic parameters. Conclusions These results suggest that combining CR and ResS may decrease the beneficial effects of each alone. Furthermore, CR , regardless of dietary salt intake, inappropriately activates aldosterone production. Thus, caution should be used in combining ResS and CR because the combination may lead to increased cardiovascular risk.

Background and Purpose The plasma membrane protein caveolin-1 (CAV-1) has been shown to be involved in modulating glucose homeostasis and the actions of the renin-angiotensin-aldosterone system (RAAS). Caloric restriction (CR) is widely accepted as an effective therapeutic approach to improve insulin sensitivity and reduce the severity of diabetes. Recent data indicate that polymorphisms of the CAV-1 gene are strongly associated with insulin resistance, hypertension and metabolic abnormalities in non-obese individuals. Therefore, we sought to determine whether CR improves the metabolic and cardiovascular (CV) risk factors in the lean CAV-1 KO mice. Materials/Methods Twelve- to fourteen-week-old CAV-1 knockout (KO) and genetically matched wild-type (WT) male mice were randomized by genotype to one of two dietary regimens: ad libitum (ad lib) food intake or 40% CR for 4 weeks. Three weeks following the onset of dietary restriction, all groups were assessed for insulin sensitivity. At the end of the study, all groups were assessed for fasting glucose, insulin, HOMA-IR, lipids, corticosterone levels and blood pressure (BP). Aldosterone secretion was determined from acutely isolated Zona Glomerulosa cells. Results We confirmed that the CAV-1 KO mice on the ad lib diet display a phenotype consistent with the cardiometabolic syndrome, as shown by higher systolic BP (SBP), plasma glucose, HOMA-IR and aldosterone levels despite lower body weight compared with WT mice on the ad lib diet. CAV-1 KO mice maintained their body weight on the ad lib diet, but had substantially greater weight loss with CR, as compared to caloric restricted WT mice. CR-mediated changes in weight were associated with dramatic improvements in glucose and insulin tolerance in both genotypes. These responses to CR, however, were more robust in CAV-1KO vs. WT mice and were accompanied by reductions in plasma glucose, insulin and HOMA-IR in CAV-1KO but not WT mice. Surprisingly, in the CAV-1 KO, but not in WT mice, CR was associated with increased SBP and aldosterone levels, suggesting that in CAV-1 KO mice CR induced an increase in some CV risk factors. Conclusions CR improved the metabolic phenotype in CAV-1 KO mice by increasing insulin sensitivity; nevertheless, this intervention also increased CV risk by inappropriate adaptive responses in the RAAS and BP.

Aldosterone's functions and mechanisms of action are different depending on the tissue and the environmental condition. The mineralocorticoid receptor is present in tissues beyond epithelial cells, including the heart and vessels. Furthermore, aldosterone has direct adverse effects by both genomic and rapid/nongenomic actions not only through a nuclear receptor but also through caveolae-mediated intracellular events. Also, multiple environmental-genetic interactions play an important role in salt-sensitive hypertension (SSH) and aldosterone modulation. These findings have reshaped our vision of aldosterone's role in cardiovascular pathophysiology. This review describes new mediators of aldosterone's mechanisms of action: lysine-specific demethylase 1 (LSD1), caveolin 1 (cav-1) and striatin.LSD1, an epigenetic regulator, is involved in the pathogenesis of SSH in both humans and rodents. In addition, cav-1, the main component of caveolae, plays a substantial role in mediating aldosterone pathways of SSH. The mineralocorticoid receptor interacts with cav-1 and is modulated by sodium intake. Finally, striatin, a scaffolding protein, mediates a novel interaction between signalling molecules and mineralocorticoid receptor's rapid effects in the cardiovascular system.Substantial progress in aldosterone's functions and mechanisms of action should facilitate the study of cardiovascular diseases and the role of sodium intake in aldosterone-induced damage.

Hyperglycemia and endothelial dysfunction are associated with hypertension, but the specific causality and genetic underpinning are unclear. Caveolin-1 (cav-1) is a plasmalemmal anchoring protein and modulator of vascular function and glucose homeostasis. Cav-1 gene variants are associated with reduced insulin sensitivity in hypertensive individuals, and cav-1(-/-) mice show endothelial dysfunction, hyperglycemia, and increased blood pressure (BP). On the other hand, insulin-sensitizing therapy with metformin may inadequately control hyperglycemia while affecting the vascular outcome in certain patients with diabetes. To test whether the pressor and vascular changes in cav-1 deficiency states are related to hyperglycemia and to assess the vascular mechanisms of metformin under these conditions, wild-type (WT) and cav-1(-/-) mice were treated with either placebo or metformin (400 mg/kg daily for 21 days). BP and fasting blood glucose were in cav-1(-/-)WT and did not change with metformin. Phenylephrine (Phe)- and KCl-induced aortic contraction was in cav-1(-/-)WT; endothelium removal, the nitric-oxide synthase (NOS) blocker L-NAME (N(ω)-nitro-L-arginine methyl ester), or soluble guanylate cyclase (sGC) inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) enhanced Phe contraction, and metformin blunted this effect. Acetylcholine-induced relaxation was in cav-1(-/-)WT, abolished by endothelium removal, L-NAME or ODQ, and reduced with metformin. Nitric oxide donor sodium nitroprusside was more potent in inducing relaxation in cav-1(-/-) than in WT, and metformin reversed this effect. Aortic eNOS, AMPK, and sGC were in cav-1(-/-)WT, and metformin decreased total and phosphorylated eNOS and AMPK in cav-1(-/-). Thus, metformin inhibits both vascular contraction and NO-cGMP-dependent relaxation but does not affect BP or blood glucose in cav-1(-/-) mice, suggesting dissociation of hyperglycemia from altered vascular function in cav-1-deficiency states.

Background Overactivation of the aldosterone and mineralocorticoid receptor ( MR ) pathway is associated with hyperglycemia and dyslipidemia. Caveolin 1 (cav‐1) is involved in glucose/lipid homeostasis and may modulate MR signaling. We investigated the interplay between cav‐1 and aldosterone signaling in modulating insulin resistance and dyslipidemia in cav‐1–null mice and humans with a prevalent variant in the CAV 1 gene. Methods and Results In mouse studies, cav‐1 knockout mice exhibited higher levels of homeostatic model assessment of insulin resistance, cholesterol, and resistin and lower ratios of high‐ to low‐density lipoprotein (all P mRNA levels for resistin, retinol binding protein 4, NADPH oxidase 4, and aldose reductase in liver and/or fat tissues. MR blockade with eplerenone significantly decreased glycemia ( P P P CAV 1 gene polymorphism rs926198 in 556 white participants; 58% were minor allele carriers and displayed higher odds of insulin resistance (odds ratio 2.26 [95% CI 1.40–3.64]) and low high‐density lipoprotein (odds ratio 1.54 [95% CI 1.01–3.37]). Aldosterone levels correlated with higher homeostatic model assessment of insulin resistance and resistin and lower high‐density lipoprotein only in minor allele carriers. CAV 1 gene expression quantitative trait loci data revealed lower cav‐1 expression in adipose tissues by the rs926198 minor allele. Conclusions Our findings in mice and humans suggested that decreased cav‐1 expression may activate the effect of aldosterone/ MR signaling on several pathways of glycemia, dyslipidemia, and resistin. In contrast, hyperinsulinemia and hypertriglyceridemia are likely mediated by MR ‐independent mechanisms. Future human studies will elucidate the clinical relevance of MR blockade in patients with genotype‐mediated cav‐1 deficiency.

Lysine-Specific Demethylase1 (LSD1) is an epigenetic factor modulated by salt intake. Previously, we documented the male heterozygote LSD1 knockout mice (LSD1+/-) had dysregulation of aldosterone (ALDO) production on a liberal salt diet (1.6% Na+) associated with salt-sensitive hypertension. This study assessed if: 1) female LSD1+/- mice have a similar phenotype; and 2) the effect of aging on this phenotype. Methods: Female LSD1+/- and wild type mice (LSD1+/+) were randomly assigned for sacrifice at the ages of 18-week, 52-week, and 75-week and the following were assessed at each time point: blood pressure (BP); plasma renin activity (PRA) and ALDO; urine albumin; and ex vivo ALDO production from isolated adrenal zona glomerulosa cells. Results: BP and urine albumin in the LSD1+/- compared to the LSD1+/+ were not different at any age (Table). However, the LSD1+/- had greater ALDO/PRA ratios at 18 weeks compared with the LSD1+/+, but lower ALDO levels and ex vivo ALDO production at 52 and 75 weeks. Associated with this phenotype, the LSD1+/- showed significantly higher rate of all-cause mortality than the LSD1+/+. Conclusion: Lack of LSD1 caused dysregulation of ALDO production in both male and female mice. But the cardiovascular outcomes are different. The LSD1+/- females in contrast to males do not develop hypertension or albuminuria even at 75 weeks of age. However, the females do die at a faster rate than the males of a variety of causes. Thus, there is considerable sexual dimorphism in the pathogenesis of cardiovascular outcomes associated with dysregulation of adrenal ALDO production mediated by lack of LSD1.

We thank Dr Campbell for his interest in our study,1 and the fair and helpful comments from the accompanying editorial by Andersson and Vasan, as well.2 We are in agreement with Dr Campbell that statins may influence adrenal steroidogenesis via a multitude of effects. Our study focused mainly on the regulation of aldosterone by using a series of complex physiological maneuvers that included manipulation of angiotensin II and potassium. The subjects in our study were not taking antihypertensive therapy or were withdrawn of therapy, thus allowing investigation of their native physiology. In this context, our use of extreme sodium diets permitted the study of aldosterone when the renin-angiotensin system was maximally suppressed on high sodium and maximally stimulated on low sodium intake in the context of a fixed potassium diet. Therefore, all our assessments of aldosterone were conducted under conditions whereby the …

How interactions of an individual's genetic background and environmental factors, such as dietary salt intake, result in age-associated blood pressure elevation is largely unknown. Lysine-specific demethylase-1 (LSD1) is a histone demethylase that mediates epigenetic regulation and modification of gene transcription. We have shown previously that hypertensive African-American minor allele carriers of the LSD1 single nucleotide polymorphism (rs587168) display blood pressure salt sensitivity. Our goal was to further examine the effects of LSD1 genotype variants on interactions between dietary salt intake, age, and blood pressure. We found that LSD1 single nucleotide polymorphism (rs7548692) predisposes to increasing salt sensitivity during aging in normotensive Caucasian subjects. Using a LSD1 heterozygous knockout mouse model, we compared blood pressure values on low (0.02 % Na(+)) vs. high (1.6 % Na(+)) salt intake. Our results demonstrate significantly increased blood pressure salt sensitivity in LSD1-deficient compared to wild-type animals with age, confirming our findings of salt sensitivity in humans. Elevated blood pressure in LSD1(+/-) mice is associated with total plasma volume expansion and altered renal Na(+) excretion. In summary, our human and animal studies demonstrate that LSD1 is a genetic factor that interacts with dietary salt intake modifying age-associated blood pressure increases and salt sensitivity through alteration of renal Na(+) handling.

© 2015 Elsevier Inc. Context and objective We examined whether a prevalent caveolin-1 gene (CAV1) variant, previously related to insulin resistance, is associated with metabolic syndrome (MetS). Patients and methods We included subjects genotyped for the CAV1 variant rs926198 from two cohorts: 735 Caucasians from the HyperPATH multicenter study, and 810 Hispanic participants from the HTN-IR cohort. Results Minor allele carriers from HyperPATH cohort (57% of subjects) had higher Framingham risk scores, higher odds of diabetes (10.7% vs 5.7%, p = 0.016), insulin resistance (44.3% vs 35.1%, p = 0.022), low HDL (49.3% vs 39.6%, p = 0.018) and MetS (33% vs 20.5%, p < 0.001) but similar BMI. Consistently, minor allele carriers exhibited higher odds of MetS, even when adjusted for confounders and relatedness (OR 2.83 (1.73-4.63), p < 0.001). The association with MetS was replicated in the Hispanic cohort HTN-IR (OR 1.61, [1.06-2.44], p = 0.025). Exploratory analyses suggest that MetS risk is modified by a CAV1 variant-BMI status interaction, whereby the minor allele carrier status strongly predicted MetS (OR 3.86 [2.05-7.27], p < 0.001) and diabetes (OR 2.27 [1.07-4.78], p = 0.03) in non-obese, but not in obese subjects. In addition, we observed a familial aggregation for MetS diagnosis in minor allele carriers. Conclusion The prevalent CAV1 gene variant rs926198 is associated with MetS in separate Caucasian and Hispanic cohorts. These findings appear to be driven by an interaction between the genetic marker and obesity status, suggesting that the CAV1 variant may improve risk profiling in non-obese subjects. Additional studies are needed to confirm the clinical implications of our results.

The purpose of this study was to clarify the association of the angiotensinogen gene (AGT) with insulin sensitivity using single nucleotide polymorphism (SNP) and haplotype analyses in a white cohort. A candidate gene association study was conducted in white persons with and without hypertension (N = 449). Seventeen SNPs of the AGT gene and their haplotypes were analyzed for an association with homeostasis model assessment of insulin resistance (HOMA-IR). Multivariate regression model accounting for age, sex, body mass index, hypertension status, study site, and sibling relatedness was used to test the hypothesis. Nine of the 17 SNPs were significantly associated with lower HOMA-IR levels. Homozygous minor allele carriers of the most significant SNP, rs2493134 (GG), a surrogate for the gain-of-function mutation rs699 (AGT p.M268T), had significantly lower HOMA-IR levels (P = .0001) than heterozygous or homozygous major allele carriers (AG, AA). Direct genotyping of rs699 in a subset of the population showed similar results, with minor allele carriers exhibiting significantly decreased HOMA-IR levels (P = .003). Haplotype analysis demonstrated that haplotypes rs2493137A|rs5050A|rs3789678G|rs2493134A and rs2004776G|rs11122576A|rs699T|rs6687360G were also significantly associated with HOMA-IR (P = .0009, P = .02), and these results were driven by rs2493134 and rs699. This study confirms an association between the AGT gene and insulin sensitivity in white humans. Haplotype analysis extends this finding and implicates SNPs rs2493134 and rs699 as the most influential. Thus, AGT gene variants, previously shown to be associated with AGT levels, are also associated with insulin sensitivity; suggesting a relationship between the AGT gene, AGT levels, and insulin sensitivity in humans.

The co-occurrence of insulin resistance (IR) and hypertension is a heritable condition leading to cardiovascular complications. Caveolin-1 (CAV1), a gene previously associated with metabolic dysfunction in animal and cellular models, may be a marker for these conditions in humans.The objective of the study was to examine the relationship between CAV1 variants and IR in two hypertensive cohorts and to corroborate the findings in a CAV1 knockout mouse.A candidate gene association study was conducted in two hypertensive cohorts: 1) Caucasian and 2) Hispanic. Multivariate associations between individual variants and insulin-resistant phenotypes were analyzed, accounting for age, gender, body mass index, and sibling relatedness. Intraperitoneal glucose tolerance tests were conducted in wild-type and CAV1 knockout mice.In the Caucasian hypertensive cohort, minor allele carriers of two CAV1 single-nucleotide polymorphisms (rs926198, rs3807989) had significantly higher fasting insulin levels (P = 0.005, P = 0.007), increased homeostatic assessment model for insulin resistance (HOMA-IR) (P =0.005, P = 0.008), and decreased M value during hyperinsulinemic, euglycemic clamp procedure (P = 0.004, P = 0.05) than major allele homozygotes. Findings were replicated in the Hispanic hypertensive cohort cohort for fasting insulin levels (P = 0.005, P = 0.02) and HOMA-IR (P = 0.008 and P = 0.02). Meta-analysis demonstrated significant associations of both single-nucleotide polymorphisms with fasting insulin levels (P = 0.00008, P = 0.0004) and HOMA-IR (P = 0.0001, P = 0.0004). As compared with wild type, CAV1 knockout mice displayed higher blood pressure levels and higher fasting glucose, insulin, and HOMA-IR levels and an exaggerated glycemic response to a glucose challenge.Variations in the CAV1 gene are associated with IR and hypertension. CAV1 gene polymorphisms may be a biomarker for IR and hypertension, enabling earlier detection and improved treatment strategies.

ObjectivePrevious studies have suggested that circulating adiponectin concentrations are associated positively with vitamin D and negatively with body mass index (BMI) but have not accounted for the influence of the renin–angiotensin–aldosterone system (RAAS) in this relationship. This is particularly relevant because increased RAAS activity is associated with obesity and is known to lower adiponectin levels. We evaluated the association between adiponectin and 25-hydroxyvitamin D (25(OH)D) after controlling RAAS activity with dietary sodium equilibration and also evaluated whether this relationship was influenced by BMI.DesignCross-sectional study of 115 hypertensive Caucasian men from the Hypertensive Pathotype Consortium.MethodsTo manipulate RAAS activity, all subjects underwent 1 week of high dietary sodium (HS) diet to suppress RAAS and 1 week of low dietary sodium (LS) diet to stimulate RAAS. Linear regression was used to evaluate the association between adiponectin and 25(OH)D, and the effect of BMI on this relationship, in each dietary condition.ResultsAdiponectin was higher on HS, where circulating RAAS activity was low, when compared with LS (HS=2.9 versus LS=2.4 μg/ml, PP interaction ConclusionsHigher 25(OH)D concentrations were independently associated with higher adiponectin levels, particularly when BMI was high. Dietary sodium balance and circulating RAAS activity did not appear to affect this relationship. Future studies should explore whether vitamin D supplementation increases adiponectin levels in obesity.

The purpose of the present article is to provide an overview of plasma membrane steroid hormone receptors and their implications in nongenomic signaling. We especially focus on recent evidence supporting the notion of a possible membrane-associated aldosterone receptor, whether this receptor is different from the classic nuclear receptor, and the possible implications of such a receptor for nongenomic and genomic aldosterone effects in physiological and pathophysiological processes.

Peroxisome proliferator-activated receptor gamma (PPARgamma) agonists often cause volume retention and edema. A relationship between PPARgamma and renin may play a role in this process.The aim was to examine the relationship between the PPARgamma gene and plasma renin activity (PRA) levels in human hypertension.A candidate gene association study was conducted with two distinct groups of human participants: Caucasian hypertensives (n = 395) and African-American hypertensives (n = 55). Single nucleotide polymorphisms of the PPAR(Upsilon) gene were analyzed. Phenotype studies were conducted after participants consumed a low-salt diet (10 mmol/d) for 7 d and included PRA and aldosterone measurements before and after a 60-min angiotensin II infusion (3 ng/kg x min).Participants homozygous for the minor allele of rs2959272 (CC) had significantly higher PRA levels at baseline (P = 0.016) than major allele carriers (AA, AC) in Caucasian-hypertensive participants. The association of the C allele carrier status with increased PRA levels was replicated in the group of African-American hypertensive participants (P = 0.027). The Fisher's combined P value for both observations was significant (P = 0.002).These results demonstrate the first known association between a PPARgamma single nucleotide polymorphism and alterations in PRA levels in humans with hypertension. This link between PPARgamma and renin raises the possibility of a genetically based mechanism for the increased volume retention and edema in some users of PPARgamma agonists.

Endothelial caveolin-1 (cav-1) is an anchoring protein in plasma membrane caveolae where it binds endothelial nitric oxide synthase (eNOS) and limits its activation, particularly in animals fed a high salt (HS) diet. Cav-1 also interacts with steroid receptors such as the mineralocorticoid receptor (MR). To test the hypothesis that vascular reactivity is influenced by an interplay between MR and cav-1 during HS diet, we examined the effects of MR blockade on NOS-mediated vascular relaxation in normal and cav-1-deficient mice. Wild-type (WT) and cav-1 knockout mice (cav-1−/−) were fed for 14 days a HS (4% NaCl) diet with and without the MR antagonist eplerenone (Epl; 100 mg·kg−1·day−1). After systolic blood pressure (BP) was measured, the thoracic aorta was isolated for measurement of vascular reactivity, and the aorta and heart were used for measurement of eNOS and MR expression. BP was not different between WT + Epl and WT, but was higher in cav-1−/− + Epl than in cav-1−/− mice. Phenylephrine (Phe)-induced vascular contraction was less in cav-1−/− than WT, and significantly enhanced in cav-1−/− + Epl than in cav-1−/−, but not in WT + Epl compared with WT. Endothelium removal and NOS blockade by Nω-nitro-l-arginine methyl ester (l-NAME) enhanced Phe contraction in cav-1−/−, but not cav-1−/− + Epl. ACh-induced aortic relaxation was reduced in cav-1−/− + Epl versus cav-1−/−, but not in WT + Epl compared with WT. Endothelium removal, l-NAME, and the guanylate cyclase inhibitor ODQ abolished the large ACh-induced relaxation in cav-1−/− and the remaining relaxation in the cav-1−/− + Epl but had similar inhibitory effect in WT and WT + Epl. Real-time RT-PCR indicated decreased eNOS mRNA expression in the aorta and heart, and Western blots revealed decreased total eNOS in the heart of cav-1−/− + Epl compared with cav-1−/−. Vascular and cardiac MR expression was less in cav-1−/− than WT, but not in cav-1−/− + Epl compared with cav-1−/−. Plasma aldosterone (Aldo) was not different between WT and cav-1−/− mice nontreated or treated with Epl. Thus in cav-1 deficiency states and HS diet MR blockade is associated with increased BP, enhanced vasoconstriction, and decreased NOS-mediated vascular relaxation and eNOS expression. The data suggest that, in the absence of cav-1, MR activation plays a beneficial role in regulating eNOS expression/activity and, consequently, the vascular function during HS diet.

Long term exposure to salt is a demonstrated risk factor for hypertension (HT), as well as cardiovascular and renal (CVR) outcomes. We recently proposed a novel contributor to the etiology of salt-mediated HT: the Lysine Specific Demethylase-1 (LSD1). We showed that LSD1 deficiency (in mice) and LSD1 gene variants (in humans) associate - in response to short term (one week) of sodium loading - with dysregulated renal sodium handling, volume expansion and HT, and RAAS dysfunction. However, the timeline and severity of these changes during long term exposure to sodium, and the protective effects of sodium restriction in LSD1 deficient states have yet to be determined. This study aimed (1) to evaluate the timing of onset for changes in CVR health during long term sodium loading in LSD1 deficient mice and (2) to assess whether a low salt (LS) diet can prevent these effects. LSD1 heterozygous (HET) and WT mice were randomized to high salt (HS) or LS and followed longitudinally for 6 months. BP, plasma aldosterone (Aldo) and albumin/creatinine ratios (A/C) were assessed monthly. The SBP (mm Hg) increased progressively during the study, and reached significance on the 5 th and 6 th month for HS-HET and HS-WT (141±4 and 134±3, respectively, both p The A/C (μg/mg) was progressively increased in both HS groups, one month prior to the BP change. Namely, A/C reached significance on the 4 th and 5 th month for HS-HET and HS-WT (46±4 and 48±9, respectively, both p Our novel study shows that long term exposure to HS induces kidney damage followed by BP increase, and that these changes are initiated earlier in the LSD1 HET, suggesting LSD1 as a critical component of mechanisms involved in CVR health. Moreover, long term sodium restriction prevented the development of both target organ damage and HT in this model, suggesting that this dietary intervention may be particularly efficient in human carriers of LSD1 gene variants.

Background— Statins substantially reduce cardiovascular mortality and appear to have beneficial effects independent of their lipid-lowering properties. We evaluated the hypothesis that statin use may modulate the secretion of aldosterone, a well-known contributor to cardiovascular disease. Methods and Results— We measured adrenal hormones in 2 intervention studies. In study 1 in hypertensive subjects, aldosterone was analyzed at baseline and after angiotensin II stimulation on both high- and low-sodium diets (1122 observations, 15% on statins for >3 months). Statin users had 33% lower aldosterone levels in adjusted models ( P P P =0.006), particularly those using lipophilic statins. Ex vivo studies in rat adrenal glomerulosa cells confirmed that lipophilic statins acutely inhibited aldosterone, but not corticosterone, in response to different secretagogues. Conclusions— Statin use among hypertensive and diabetic subjects was associated with lower aldosterone secretion in response to angiotensin II and a low-sodium diet in 2 human intervention studies. This effect appeared to be most pronounced with lipophilic statins and higher doses. Future studies to evaluate whether aldosterone inhibition may partially explain the robust cardioprotective effects of statins are warranted.