Human adipocytes secrete mineralocorticoid-releasing factors

Masked phenomenon: renal and cardiovascular complications; review and updates

BACKGROUND

In the in-clinic blood pressure (BP) recording setting, a sizable number of individuals with normal BP and approximately 30% of patients with chronic renal disease (CKD) exhibit elevated outpatient BP records. These individuals are known as masked hypertension (MHTN), and when they are on antihypertensive medications, but their BP is not controlled, they are called masked uncontrolled hypertension (MUHTN). The masked phenomenon (MP) (MHTN and MUHTN) increases susceptibility to end-organ damage (a two-fold greater risk for cardiovascular events and kidney dysfunction). The potential extension of the observed benefits of MP therapy, including a reduction in end-organ damage, remains questionable.

AIM AND METHODS

This review aims to study the diagnostic methodology, epidemiology, pathophysiology, and significance of MP management in end-organs, especially the kidneys, cardiovascular system, and outcomes. To achieve the purposes of this non-systematic comprehensive review, PubMed, Google, and Google Scholar were searched using keywords, texts, and phrases such as masked phenomenon, CKD and HTN, HTN types, HTN definition, CKD progression, masked HTN, MHTN, masked uncontrolled HTN, CKD onset, and cardiovascular system and MHTN. We restricted the search process to the last ten years to search for the latest updates.

CONCLUSION

MHTN is a variant of HTN that can be missed if medical professionals are unaware of it. Early detection by ambulatory or home BP recording in susceptible individuals reduces end-organ damage and progresses to sustained HTN. Adherence to the available recommendations when dealing with masked phenomena is justifiable; however, further studies and recommendation updates are required.

Salt-Sensitive Hypertension and the Kidney

Salt-sensitive hypertension (SS-HT) is characterized by blood pressure elevation in response to high dietary salt intake and is considered to increase the risk of cardiovascular and renal morbidity. Although the mechanisms responsible for SS-HT are complex, the kidneys are known to play a central role in the development of SS-HT and the salt sensitivity of blood pressure (SSBP). Moreover, several factors influence renal function and SSBP, including the renin-angiotensin-aldosterone system, sympathetic nervous system, obesity, and aging. A phenotypic characteristic of SSBP is aberrant activation of the renin-angiotensin system and sympathetic nervous system in response to excessive salt intake. SSBP is also accompanied by a blunted increase in renal blood flow after salt loading, resulting in sodium retention and SS-HT. Obesity is associated with inappropriate activation of the aldosterone mineralocorticoid receptor pathway and renal sympathetic nervous system in response to excessive salt, and mineralocorticoid receptor antagonists and renal denervation attenuate sodium retention and inhibit salt-induced blood pressure elevation in obese dogs and humans. SSBP increases with age, which has been attributed to impaired renal sodium handling and a decline in renal function, even in the absence of kidney disease. Aging-associated changes in renal hemodynamics are accompanied by significant alterations in renal hormone levels and renal sodium handling, resulting in SS-HT. In this review, we focus mainly on the contribution of renal function to the development of SS-HT.

Unveiling Selected Influences on Chronic Kidney Disease Development and Progression

Currently, more and more people are suffering from chronic kidney disease (CKD). It is estimated that CKD affects over 10% of the population worldwide. This is a significant issue, as the kidneys largely contribute to maintaining homeostasis by, among other things, regulating blood pressure, the pH of blood, and the water-electrolyte balance and by eliminating unnecessary metabolic waste products from blood. What is more, this disease does not show any specific symptoms at the beginning. The development of CKD is predisposed by certain conditions, such as diabetes mellitus or hypertension. However, these disorders are not the only factors promoting the onset and progression of CKD. The primary purpose of this review is to examine renin-angiotensin-aldosterone system (RAAS) activity, transforming growth factor-β1 (TGF-β1), vascular calcification (VC), uremic toxins, and hypertension in the context of their impact on the occurrence and the course of CKD. We firmly believe that a deeper comprehension of the cellular and molecular mechanisms underlying CKD can lead to an enhanced understanding of the disease. In the future, this may result in the development of medications targeting specific mechanisms involved in the decline of kidney function. Our paper unveils the selected processes responsible for the deterioration of renal filtration abilities.

Subtype-specific Body Composition and Metabolic Risk in Patients With Primary Aldosteronism

BACKGROUND

Primary aldosteronism (PA) is associated with increased metabolic risks. However, controversy exists as to which subtype of PA has a higher metabolic risk between bilateral and lateralized PA. This study aimed to assess the body composition of 2 PA subtypes, bilateral PA and lateralized PA, according to sex and autonomous cortisol secretion (ACS) and their contribution to comorbidities.

DESIGN AND METHODS

A total of 400 patients with PA (females, n = 210) and 1:10 age- and sex-matched healthy controls (n = 4000) were enrolled. The skeletal muscle area (SMA), subcutaneous fat area, and visceral fat area (VFA) at the third lumbar spine were calculated using abdominal computed tomography-based body composition analysis.

RESULTS

Patients with bilateral PA had higher body mass index (BMI) in both sexes (all P < .05). Hemoglobin A1c level and the prevalence of diabetes were higher in female patients with bilateral PA than in those with lateralized PA (all P < .05). The VFA/BMI ratio was significantly higher in bilateral PA patients than in lateralized PA patients (5.77 ± 2.69 vs 4.56 ± 2.35 in men; 4.03 ± 2.58 vs 2.53 ± 2.05 in women, all P < .001). PA patients with ACS showed decreased SMA compared to those without ACS. Compared with healthy controls, all patients with bilateral PA and female patients with lateralized PA showed significantly higher VFA and VFA/BMI.

CONCLUSIONS

Patients with bilateral PA were more obese and had higher VFA levels than those with lateralized PA. Despite a milder form of PA, this metabolically unfavorable visceral fat distribution may lead to a higher metabolic risk in patients with bilateral PA.

Sensitivity of the Neuroendocrine Stress Axis in Metabolic Diseases

Metabolic diseases are prevalent in modern society and have reached pandemic proportions. Metabolic diseases have systemic effects on the body and can lead to changes in the neuroendocrine stress axis, the critical regulator of the body's stress response. These changes may be attributed to rising insulin levels and the release of adipokines and inflammatory cytokines by adipose tissue, which affect hormone production by the neuroendocrine stress axis. Chronic stress due to inflammation may exacerbate these effects. The increased sensitivity of the neuroendocrine stress axis may be responsible for the development of metabolic syndrome, providing a possible explanation for the high prevalence of severe comorbidities such as heart disease and stroke associated with metabolic disease. In this review, we address current knowledge of the neuroendocrine stress axis in response to metabolic disease and discuss its role in developing metabolic syndrome.

Effect of Obesity on Clinical Characteristics of Primary Aldosteronism Patients at Diagnosis and Postsurgical Response

CONTEXT

Patients with obesity have an overactivated renin-angiotensin-aldosterone system (RAAS) that is associated with essential hypertension. However, the influence of obesity in primary aldosteronism (PA) is unknown.

OBJECTIVE

We analyzed the effect of obesity on the characteristics of PA, and the association between obesity and RAAS components.

METHODS

A retrospective study was conducted of the Spanish PA Registry (SPAIN-ALDO Registry), which included patients with PA seen at 20 tertiary centers between 2018 and 2022. Differences between patients with and without obesity were analyzed.

RESULTS

A total of 415 patients were included; 189 (45.5%) with obesity. Median age was 55 years (range, 47.3-65.2 years) and 240 (58.4%) were male. Compared to those without obesity, patients with obesity had higher rates of diabetes mellitus, chronic kidney disease, obstructive apnea syndrome, left ventricular hypertrophy, prior cardiovascular events, higher means of systolic blood pressure, and required more antihypertensive drugs. Patients with PA and obesity also had higher values of serum glucose, glycated hemoglobin A1c, creatinine, uric acid, and triglycerides, and lower levels of high-density lipoprotein cholesterol. Levels of blood aldosterone (PAC) and renin were similar between patients with and without obesity. Body mass index was not correlated with PAC nor renin. The rates of adrenal lesions on imaging studies, as well as the rates of unilateral disease assessed by adrenal vein sampling or I-6β-iodomethyl-19-norcholesterol scintigraphy, were similar between groups.

CONCLUSION

Obesity in PA patients involves a worse cardiometabolic profile, and need for more antihypertensive drugs but similar PAC and renin levels, and rates of adrenal lesions and lateral disease than patients without obesity. However, obesity implicates a lower rate of hypertension cure after adrenalectomy.

Association of Reversal of Renin Suppression With Long-Term Renal Outcome in Medically Treated Primary Aldosteronism

BACKGROUND

Renin suppression in primary aldosteronism indicates mineralocorticoid receptor activation via excessive aldosterone secretion, inducing renal damage. We investigated whether the reversal of renin suppression after the initiation of mineralocorticoid receptor antagonist therapy was associated with long-term renal outcomes in medically treated patients with primary aldosteronism.

METHODS

This retrospective cohort study included 318 patients with primary aldosteronism treated with mineralocorticoid receptor antagonist between 2008 and 2020 at the Yokohama Rosai Hospital in Japan. The posttreatment renin status was defined as unsuppressed (ie, reversal of renin suppression) when individual plasma renin activity after the initiation of mineralocorticoid receptor antagonist (post-plasma renin activity) was ≥1.0 ng/mL per hour; otherwise, it was defined as suppressed. We analyzed the association of posttreatment renin status with subsequent longitudinal estimated glomerular filtration rate changes using linear mixed-effects models for repeated measurements, adjusting for potential confounders.

RESULTS

The posttreatment renin status of 119 patients was unsuppressed (median post-plasma renin activity, 1.7 ng/mL per hour) and that of 199 patients was suppressed (median post-PRA, 0.5 ng/mL per hour). Through the median follow-up period of 3.1 years, the decline in estimated glomerular filtration rate was milder among patients with the unsuppressed posttreatment renin (-0.46 [95% CI, -0.63 to -0.28] mL/min per 1.73 m2 per year) than those with suppressed posttreatment renin (-1.41 [95% CI, -1.56 to -1.27] mL/min per 1.73 m2 per year; difference, 0.96 [95% CI, 0.72-1.20] mL/min per 1.73 m2 per year).

CONCLUSIONS

Our findings may highlight the importance of reversing renin suppression with optimal mineralocorticoid receptor antagonist titration in medically treated primary aldosteronism, which could mitigate adverse renal outcomes.

Prevalence of primary aldosteronism in patients with concomitant hypertension and obstructive sleep apnea, baseline data of a cohort

Obstructive sleep apnea (OSA) and primary aldosteronism (PA) often coexist in hypertension, whereas whether hypertensive patients with OSA should be screened for PA is controversial and whether gender, age, obesity and OSA severity should be considered is unexplored. We explored cross-sectionally prevalence and associated factors of PA in co-existent hypertension and OSA by considering gender, age, obesity and OSA severity. OSA was defined as AHI ≥5 events/h. PA diagnosis was defined, based on the 2016 Endocrine Society Guideline. We included 3306 patients with hypertension (2564 with OSA). PA prevalence was significantly higher in hypertensives with OSA than in those without OSA (13.2 vs 10.0%, P = 0.018). In gender-specific analysis, PA prevalence was significantly higher in hypertensive men with OSA, compared to non-OSA ones (13.8 vs 7.7%, P = 0.001). In further analysis, PA prevalence was significantly higher in hypertensive men with OSA aged <45 years (12.7 vs 7.0%), 45-59 years (16.6 vs 8.5%), and with overweight and obesity (14.1 vs 7.1%) than did their counterparts (P < 0.05). For OSA severity, men participants showed increased PA prevalence from non to moderate OSA and a decrease in the severe OSA group (7.7 vs 12.9 vs 15.1 vs 13.7%, P = 0.008). Young and middle age, moderate-severe OSA, weight, and blood pressure showed a positive independent association with PA presence in logistic regression. In conclusion, PA is prevalent in co-existent hypertension and OSA, indicating the need for PA screening. Studies are needed for women, older and lean population due to the smaller samples in this study.

Effect of the interaction between the visceral-to-subcutaneous fat ratio and aldosterone on cardiac function in patients with primary aldosteronism

Primary aldosteronism is the most frequent secondary hypertensive disease and is characterized by an elevated risk for cardiovascular disease. The current standard treatments are adrenalectomy and/or administration of mineralocorticoid receptor blockers, both of which are effective at ameliorating hypertension via intervention for hyperaldosteronism. However, both of these approaches have side effects and contraindications, and mineralocorticoid receptor blockers also have limited preventive efficacy against cardiovascular events. Recently, in vitro experiments have shown that aldosterone regulation is closely related to abdominal fat accumulation and that there is crosstalk between aldosterone and visceral fat tissue accumulation. We previously reported that this interaction was clinically significant in renal dysfunction; however, its effects on the heart remain unclear. Here, we analyzed data from 49 patients with primary aldosteronism and 29 patients with essential hypertension to examine the potential effect of the interaction between the ratio of visceral-to-subcutaneous fat tissue volume and the plasma aldosterone concentration on echocardiographic indices, including the tissue Doppler-derived E/e' ratio. A significant interaction was found in patients with primary aldosteronism (p < 0.05), indicating that patients with the combination of a high plasma aldosterone concentration and high visceral-to-subcutaneous fat ratio show an increased E/e' ratio, which is a well-known risk factor for future cardiovascular events. Our results confirm the clinical importance of the interaction between aldosterone and abdominal fat tissue, suggesting that an improvement in the visceral-to-subcutaneous fat ratio may be synergistically and complementarily effective in reducing the elevated risk of cardiovascular disease in patients with primary aldosteronism when combined with conventional therapies for reducing aldosterone activity. A significant effect of the interaction between plasma aldosterone concentration and the visceral-to-subcutaneous fat ratio on the tissue Doppler-derived E/e' ratio in patients with primary aldosteronism.

Fatty acids as a direct regulator of aldosterone hypersecretion

Primary hyperaldosteronism is a major cause of secondary hypertension and carries additional cardiovascular risks beyond that of the elevated blood pressure. Primary hyperaldosteronism is more prevalent in obese people, and weight loss reduces aldosterone levels. It needs to be determined whether obesity related factors directly contribute to the pathogenesis of primary hyperaldosteronism. Here we show that the non-esterified fatty acids (NEFA) palmitic acid, and to a lesser extent, linoleic acid significantly stimulated aldosterone production and steroid enzyme induction in adrenocortical HAC15 cells of human origin. Palmitic acid, linoleic acid, and to a much lesser extent, oleic acid induced the expression of aldosterone synthase. Induction of the Steroidogenic Acute Regulatory Protein (StAR) was modest. Increased aldosterone secretion was independent of fatty acid beta-oxidation in the mitochondria but may involve free fatty acid receptor 1 (FFAR1/GPR40) and endoplasmic reticulum (ER) stress. Palmitic acid and linoleic acid induced the expression of C/EBP Homologous Protein (CHOP), a marker of ER stress, correlating with their ability to induce aldosterone synthase gene expression. Palmitic acid, but not linoleic acid decreased mitochondrial potentials and induced uncoupling protein 2 (UCP2). Palmitic acid enhanced, while docosahexaenoic acid (DHA) suppressed aldosterone response to angiotensin II (Ang-II). Our study provides evidence that NEFAs modulate aldosterone production, and further suggests that hyperaldosteronism shares similar pathogenesis with other obesity-related disorders such as metabolic syndrome.

Autophagy in graves' ophthalmopathy

Graves' ophthalmopathy (GO) is an inflammatory autoimmune disease that affects the eyes. It can significantly alter the quality of life in patients because of its distinctive pathological appearance and the effect on vision. To date, the exact pathological mechanism of GO has not been explicitly discovered. However, several studies have associated autophagy with this disease. Autophagy is a catabolic process that helps maintain homeostasis in all organisms by protecting the cells and tissues from various endogenous and exogenous stress factors. Based on our results, patients affected with GO have comparatively elevated levels of autophagy, which critically affects the pathological mechanism of the GO. In this review, we have summarized the autophagy mechanism in the pathogenesis of GO.

The emerging role of leptin in obesity-associated cardiac fibrosis: evidence and mechanism

Cardiac fibrosis is a hallmark of various cardiovascular diseases, which is quite commonly found in obesity, and may contribute to the increased incidence of heart failure arrhythmias, and sudden cardiac death in obese populations. As an endogenous regulator of adiposity metabolism, body mass, and energy balance, obesity, characterized by increased circulating levels of the adipocyte-derived hormone leptin, is a critical contributor to the pathogenesis of cardiac fibrosis. Although there are some gaps in our knowledge linking leptin and cardiac fibrosis, this review will focus on the interplay between leptin and major effectors involved in the pathogenesis underlying cardiac fibrosis at both cellular and molecular levels based on the current reports. The profibrotic effect of leptin is predominantly mediated by activated cardiac fibroblasts but may also involve cardiomyocytes, endothelial cells, and immune cells. Moreover, a series of molecular signals with a known profibrotic property is closely involved in leptin-induced fibrotic events. A more comprehensive understanding of the underlying mechanisms through which leptin contributes to the pathogenesis of cardiac fibrosis may open up a new avenue for the rapid emergence of a novel therapy for preventing or even reversing obesity-associated cardiac fibrosis.

The metabolic phenotype of patients with primary aldosteronism: impact of subtype and sex - a multicenter-study of 3566 Caucasian and Asian subjects

BACKGROUND

Accumulating evidence suggests that primary aldosteronism (PA) is associated with several features of the metabolic syndrome, in particular with obesity, type 2 diabetes mellitus, and dyslipidemia. Whether these manifestations are primarily linked to aldosterone-producing adenoma (APA) or bilateral idiopathic hyperaldosteronism (IHA) remains unclear. The aim of the present study was to investigate differences in metabolic parameters between APA and IHA patients and to assess the impact of treatment on these clinical characteristics.

METHODS

We conducted a retrospective multicenter study including 3566 patients with APA or IHA of Caucasian and Asian origin. We compared the prevalence of metabolic disorders between APA and IHA patients at the time of diagnosis and 1-year post-intervention, with special references to sex differences. Furthermore, correlations between metabolic parameters and plasma aldosterone, renin, or plasma cortisol levels after 1 mg dexamethasone (DST) were performed.

RESULTS

As expected, APA patients were characterized by higher plasma aldosterone and lower serum potassium levels. Only female IHA patients demonstrated significantly worse metabolic parameters than age-matched female APA patients, which were associated with lower cortisol levels upon DST. One-year post-intervention, female adrenalectomized patients showed deterioration of their lipid profile, when compared to patients treated with mineralocorticoid receptor antagonists. Plasma aldosterone levels negatively correlated with the BMI only in APA patients.

CONCLUSIONS

Metabolic alterations appear more prominent in women with IHA. Although IHA patients have worse metabolic profiles, a correlation with cortisol autonomy is documented only in APAs, suggesting an uncoupling of cortisol action from metabolic traits in IHA patients.

Paradigm Shift in Phytochemicals Research: Evolution from Antioxidant Capacity to Anti-Inflammatory Effect and to Roles in Gut Health and Metabolic Syndrome

Food bioactive components, particularly phytochemicals with antioxidant capacity, have been extensively studied over the past two decades. However, as new analytical and molecular biological tools advance, antioxidants related research has undergone significant paradigm shifts. This review is a high-level overview of the evolution of phytochemical antioxidants research. Early research used chemical models to assess the antioxidant capacity of different phytochemicals, which provided important information about the health potential, but the results were overused and misinterpreted despite the lack of biological relevance (Antioxidants v1.0). This led to findings in the anti-inflammatory properties and modulatory effects of cell signaling of phytochemicals (Antioxidants v2.0). Recent advances in the role of diet in modulating gut microbiota have suggested a new phase of food bioactives research along the phytochemicals-gut microbiota-intestinal metabolites-low-grade inflammation-metabolic syndrome axis (Antioxidants v3.0). Polyphenols and carotenoids were discussed in-depth, and future research directions were also provided.

The Diabetic Cardiorenal Nexus

The end-stage of the clinical combination of heart failure and kidney disease has become known as cardiorenal syndrome. Adverse consequences related to diabetes, hyperlipidemia, obesity, hypertension and renal impairment on cardiovascular function, morbidity and mortality are well known. Guidelines for the treatment of these risk factors have led to the improved prognosis of patients with coronary artery disease and reduced ejection fraction. Heart failure hospital admissions and readmission often occur, however, in the presence of metabolic, renal dysfunction and relatively preserved systolic function. In this domain, few advances have been described. Diabetes, kidney and cardiac dysfunction act synergistically to magnify healthcare costs. Current therapy relies on improving hemodynamic factors destructive to both the heart and kidney. We consider that additional hemodynamic solutions may be limited without the use of animal models focusing on the cardiomyocyte, nephron and extracellular matrices. We review herein potential common pathophysiologic targets for treatment to prevent and ameliorate this syndrome.

Association of objective and subjective parameters of obstructive sleep apnea with plasma aldosterone concentration in 2,066 hypertensive and 25,368 general population

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) severity has been suggested in aldosterone elevation in resistant hypertension, whereas it is undetermined in the rest population. We explored the association of OSA parameters with plasma aldosterone concentration (PAC) in participants with and without hypertension.

METHODS

We enrolled clinically hypertensive patients with polysomnography and PAC data under no interfering agents, compared (log) PAC, and assessed the linearity of log PAC by tertiles (T1/2/3) of sleep parameters and their association using linear regression by gender and age. We enrolled participants with and without hypertension who had No-SAS scale and PAC data from the community and duplicated the observations from clinical setting considering age, gender, and presence of hypertension.

RESULTS

Of the 2,066 clinical patients with hypertension (1,546 with OSA), men participants (n=1,412), log apnea-hypopnea index (p=0.043), apnea index (AI, p=0.010), and lowest oxygen saturation (LSaO₂, p=0.013) showed significant linearity with log PAC. Log AI (B=0.04, 95%CI: 0.01,0.07, p=0.022) and log LSaO₂ (B=-0.39, 95%CI: -0.78,-0.01, p=0.044) showed significant positive and negative linear associations with log PAC in regression. In community dwellers, 6,417 participants with untreated hypertension (2,642 with OSA) and 18,951 normotensive participants (3,000 with OSA) were included. Of the men participants with and without hypertension, the OSA group showed significantly higher (log) PAC than did their counterparts, and log No-SAS score showed positive association with log PAC (hypertension: B=0.072, 95%CI: 0.002,0.142, p=0.043; normotension: B=0.103, 95%CI: 0.067,0.139, p<0.001) in linear regression analysis, which were consistent in all age groups.

CONCLUSIONS

OSA parameters were positively associated with PAC in normotensive and hypertensive participants, indicating that OSA may increase circulating aldosterone, especially in men.

Aldosterone-Regulated Sodium Transport and Blood Pressure

Aldosterone is a major mineralocorticoid steroid hormone secreted by glomerulosa cells in the adrenal cortex. It regulates a variety of physiological responses including those to oxidative stress, inflammation, fluid disruption, and abnormal blood pressure through its actions on various tissues including the kidney, heart, and the central nervous system. Aldosterone synthesis is primarily regulated by angiotensin II, K⁺ concentration, and adrenocorticotrophic hormone. Elevated serum aldosterone levels increase blood pressure largely by increasing Na⁺ re-absorption in the kidney through regulating transcription and activity of the epithelial sodium channel (ENaC). This review focuses on the signaling pathways involved in aldosterone synthesis and its effects on Na⁺ reabsorption through ENaC.

Association of renin and aldosterone with glucose metabolism in a Western European population: the KORA F4/FF4 study

INTRODUCTION

Primary aldosteronism is associated with impaired glucose tolerance. Whether plasma aldosterone and/or renin concentrations are associated with type 2 diabetes and continuous measures of glucose metabolism in the general population is still under debate.

RESEARCH DESIGN AND METHODS

The analyses included 2931 participants of the KORA F4 study at baseline and 2010 participants of the KORA FF4 study after a median follow-up of 6.5 years. The associations of active plasma renin and aldosterone concentrations with type 2 diabetes and continuous measures of glucose metabolism were assessed using logistic and linear regression models. Results were adjusted for sex, age, body mass index (BMI), estimated glomerular filtration rate, potassium, use of ACE inhibitors, angiotensin receptor blockers, beta blockers, diuretics and calcium channel blockers.

RESULTS

Cross-sectionally, renin was associated with type 2 diabetes (OR per SD: 1.25, 95% CI 1.10 to 1.43, p<0.001), fasting glucose, 2-hour glucose, insulin, proinsulin, HOMA-B (homeostasis model assessment of beta cell function) and HOMA-IR (homeostasis model assessment of insulin resistance) (all p values <0.001). Aldosterone was not associated with type 2 diabetes (OR: 1.04, 95% CI 0.91 to 1.19; p=0.547) but with insulin, proinsulin and HOMA-IR (all p values <0.001). The aldosterone-renin ratio was inversely associated with type 2 diabetes and several measures of glucose metabolism. Longitudinally, neither renin (OR: 1.12, 95% CI 0.92 to 1.36) nor aldosterone (OR: 0.91, 95% CI 0.74 to 1.11) were associated with incident type 2 diabetes. Renin was inversely associated with changes of insulin concentrations.

CONCLUSIONS

In the KORA F4/FF4 study, renin and aldosterone were not associated with incident type 2 diabetes and largely unrelated to changes of measures of glucose metabolism. Cross-sectionally, aldosterone was associated with surrogate parameters of insulin resistance. However, these associations were not independent of renin.

Gut feelings: the microbiota-gut-brain axis on steroids

The intricate connection between central and enteric nervous systems is well established with emerging evidence linking gut microbiota function as a significant new contributor to gut-brain axis signaling. Several microbial signals contribute to altered gut-brain communications, with steroids representing an important biological class that impacts central and enteric nervous system function. Neuroactive steroids contribute pathologically to neurological disorders, including dementia and depression, by modulating the activity of neuroreceptors. However, limited information is available on the influence of neuroactive steroids on the enteric nervous system and gastrointestinal function. In this review, we outline how steroids can modulate enteric nervous system function by focusing on their influence on different receptors that are present in the intestine in health and disease. We also highlight the potential role of the gut microbiota in modulating neuroactive steroid signaling along the gut-brain axis.

Increased Adiposity Appraised with CUN-BAE Is Highly Predictive of Incident Hypertension. The SUN Project

Overweight and obesity are growing worldwide and strongly associated with hypertension. The Clínica Universidad de Navarra-Body Adiposity Estimator (CUN-BAE) index is proposed as an optimal indicator of body fatness. We aimed to investigate the association of body fat as captured by the CUN-BAE index with incident hypertension in a Mediterranean population. We assessed 15,950 participants of the SUN (Seguimiento Universidad de Navarra) prospective cohort (63.7% women) initially free of hypertension. Participants completed follow-up questionnaires biennially. A validated 136-item food-frequency questionnaire was administered at baseline. We used Cox models adjusted for multiple confounders. Among 12.3 years of median follow-up (interquartile range: 8.3, 15.0 years), 2160 participants reported having received a diagnosis of hypertension. We observed a strong direct association between progressively higher the CUN-BAE index at baseline and incident hypertension during follow-up in multivariable-adjusted models for men and women, even after further adjustment for BMI ≥ 30 kg/m², showing a significant association also in non-obese participants. For each 2-unit increase in the CUN-BAE index, hypertension risk increased by 27% and 29% in men and women, respectively. The results remained significant when considering longitudinal repeated measures of changes in body fat assessed with the CUN-BAE index among the different biennial follow-up questionnaires. Our results emphasize the importance of reducing and maintaining a low body fat to prevent hypertension.

Obesity, metabolic syndrome, and inflammation: an update for anaesthetists caring for patients with obesity

Our understanding of chronic inflammation in obesity is evolving. Suggested mechanisms include hypoxia of adipose tissue and a subsequent increase in circulating cytokines. It is now known that adipose tissue, far from being an inert tissue, produces and secretes multiple peptides that influence inflammation and metabolism, including substrates of the renin-angiotensin-aldosterone system (RAAS). RAAS blocking antihypertensive medication and cholesterol-lowering agents are now being evaluated for their metabolic and inflammation-modulating effects. Surgery also has pro-inflammatory effects, which may be exacerbated in patients with obesity. This narrative review will summarise the recent literature surrounding obesity, metabolic syndrome, inflammation, and interplay with the RAAS, with evidence-based recommendations for the optimisation of patients with obesity, prior to surgery and anaesthesia.

Aldosterone-producing adenoma-harbouring KCNJ5 mutations is associated with lower prevalence of metabolic disorders and abdominal obesity

OBJECTIVE

Aldosterone overproduction and lipid metabolic disturbances between idiopathic hyperaldosteronism (IHA) and unilateral aldosterone-producing adenoma (APA) have been inconsistently linked in patients with primary aldosteronism. Moreover, KCNJ5 mutations are prevalent among APAs and enhance aldosterone synthesis in adrenal cortex. We aimed to investigate the prevalence of metabolic syndrome (MetS) in each primary aldosteronism subtype and observe the role of KCNJ5 mutations among APAs on the distribution of abdominal adipose tissues quantified using computed tomography (CT), including their changes postadrenalectomy.

DESIGN AND METHODS

We retrospectively collected 244 and 177 patients with IHA and APA at baseline. Patients with APA had undergone adrenalectomy, and gene sequencing revealed the absence (n = 75) and presence (n = 102) of KCNJ5 mutations. We also recruited 31 patients with APA who had undergone CT-scan 1-year postadrenalectomy.

RESULTS

The patients with APA harbouring KCNJ5 mutations had significantly lower prevalence of MetS and smaller distribution in waist circumference, subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) than the other groups. Logistic regression analysis indicated that the VAT area correlated significantly with KCNJ5 mutations among the APAs. Only participants with KCNJ5 mutations had significant increases in triglycerides, cholesterol, SAT, and VAT after 1-year postadrenalectomy.

CONCLUSION

This study is the first to demonstrate that MetS and abdominal obesity were less prevalent in the patients with APA harbouring KCNJ5 mutations compared with the IHA group and the non-KCNJ5-mutated APA group. Increasing prevalence of dyslipidaemia and abdominal obesity was observed in patients with KCNJ5 mutations 1-year postadrenalectomy.

Paradoxical Increase of 24-Hour Urinary Aldosterone Levels in Obese Patients With Resistant Hypertension on a High Salt Diet

BACKGROUND

Having previously reported that aldosterone levels increase progressively with body mass index (BMI), the current analysis was done to determine to what extent this association is related to dietary high salt intake. We anticipated that aldosterone levels would decrease with higher sodium status consistent with classical suppression of aldosterone release secondary to progressive fluid retention induced by high dietary sodium intake.

METHODS

Cross-sectional analysis of a large diverse cohort of 2,705 patients with resistant hypertension (HTN) seen in a referral HTN Clinic. Dietary sodium intake was indexed by 24-hour (h) urinary sodium (UNa), aldosterone status was determined by plasma aldosterone concentration, plasma renin activity, and 24 h urinary aldosterone (UAldo). Patients with normal weight served as control.

RESULTS

In this study, 1,572 individuals with complete 24 h urine collections were analyzed. Mean BMI was 32.5 ± 7.1 kg/m2 and ranged from 24.6 ± 2.4 kg/m2 (first quartile) to 41.0 ± 4.2 kg/m2 (fourth quartile). BMI was positively associated with 24 h UNa and UAldo levels (P < 0.0001), 24 h UNa and UAldo. There was a positively stronger correlation in obese (r = 0.273, P < 0.0001) compared with normal weight individuals (r = 0.108, P = 0.0342) independent of number and classes of antihypertensive medications.

CONCLUSIONS

Our analysis shows that there is an altered regulation of aldosterone in obese patients in the setting of high dietary salt intake.

Activation of Rac1-Mineralocorticoid Receptor Pathway Contributes to Renal Injury in Salt-Loaded db/db Mice

[Figure: see text].

Kidney and epigenetic mechanisms of salt-sensitive hypertension

Dietary salt intake increases blood pressure (BP) but the salt sensitivity of BP differs between individuals. The interplay of ageing, genetics and environmental factors, including malnutrition and stress, contributes to BP salt sensitivity. In adults, obesity is often associated with salt-sensitive hypertension. The children of women who experience malnutrition during pregnancy are at increased risk of developing obesity, diabetes and salt-sensitive hypertension as adults. Similarly, the offspring of mice that are fed a low-protein diet during pregnancy develop salt-sensitive hypertension in association with aberrant DNA methylation of the gene encoding type 1A angiotensin II receptor (AT_1AR) in the hypothalamus, leading to upregulation of hypothalamic AT_1AR and renal sympathetic overactivity. Ageing is also associated with salt-sensitive hypertension. In aged mice, promoter methylation leads to reduced kidney production of the anti-ageing factor Klotho and a decrease in circulating soluble Klotho. In the setting of Klotho deficiency, salt-induced activation of the vascular Wnt5a-RhoA pathway leads to ageing-associated salt-sensitive hypertension, potentially as a result of reduced renal blood flow and increased peripheral resistance. Thus, kidney mechanisms and aberrant DNA methylation of certain genes are involved in the development of salt-sensitive hypertension during fetal development and old age. Three distinct paradigms of epigenetic memory operate on different timescales in prenatal malnutrition, obesity and ageing.

Adipocyte and steroidogenic cell cross-talk in polycystic ovary syndrome

BACKGROUND

Metabolic and endocrine alterations in women with polycystic ovary syndrome (PCOS) affect adipose tissue mass and distribution. PCOS is characterised by hyperandrogenism, obesity and adipocyte dysfunction. Hyperandrogenism in PCOS drives dysfunctional adipocyte secretion of potentially harmful adipocytokines. Glucocorticoids and sex-steroids modulate adipocyte development and function. For their part, adipocyte products interact with adrenal and ovarian steroidogenic cells. Currently, the relationship between adipocyte and steroidogenic cells is not clear, and for these reasons, it is important to elucidate the interrelationship between these cells in women with and without PCOS.

OBJECTIVE AND RATIONALE

This comprehensive review aims to assess current knowledge regarding the interrelationship between adipocytes and adrenal and ovarian steroidogenic cells in animal models and humans with or without PCOS.

SEARCH METHODS

We searched for articles published in English and Portuguese in PubMed. Keywords were as follows: polycystic ovary syndrome, steroidogenesis, adrenal glands, theca cells, granulosa cells, adipocytes, adipocytokines, obesity, enzyme activation, and cytochrome P450 enzymes. We expanded the search into the references from the retrieved articles.

OUTCOMES

Glucocorticoids and sex-steroids modulate adipocyte differentiation and function. Dysfunctional adipocyte products play important roles in the metabolic and endocrine pathways in animals and women with PCOS. Most adipokines participate in the regulation of the hypothalamic-pituitary-adrenal and ovarian axes. In animal models of PCOS, hyperinsulinemia and poor fertility are common; various adipokines modulate ovarian steroidogenesis, depending on the species. Women with PCOS secrete unbalanced levels of adipocyte products, characterised by higher levels of leptin and lower levels of adiponectin. Leptin expression positively correlates with body mass index, waist/hip ratio and levels of total cholesterol, triglyceride, luteinising hormone, oestradiol and androgens. Leptin inhibits the production of oestradiol and, in granulosa cells, may modulate 17-hydroxylase and aromatase enzyme activities. Adiponectin levels negatively correlate with fat mass, body mass index, waist-hip ratio, glucose, insulin and triglycerides, and decrease androgen production by altering expression of luteinising hormone receptor, steroidogenic acute regulatory protein, cholesterol-side-chain cleavage enzyme and 17-hydroxylase. Resistin expression positively correlates with body mass index and testosterone, and promotes the expression of 17-hydroxylase enzyme in theca cells. The potential benefits of adipokines in the treatment of women with PCOS require more investigation.

WIDER IMPLICATIONS

The current data regarding the relationship between adipocyte products and steroidogenic cells are conflicting in animals and humans. Polycystic ovary syndrome is an excellent model to investigate the interrelationship among adipocyte and steroidogenic cells. Women with PCOS manifest some pathological conditions associated with hyperandrogenism and adipocyte products. In animals, cross-talk between cells may vary according to species, and the current review suggests opportunities to test new medications to prevent or even reverse several harmful sequelae of PCOS in humans. Further studies are required to investigate the possible therapeutic application of adipokines in women with obese and non-obese PCOS. Meanwhile, when appropriate, metformin use alone, or associated with flutamide, may be considered for therapeutic purposes.

Role of Rho in Salt-Sensitive Hypertension

A high amount of salt in the diet increases blood pressure (BP) and leads to salt-sensitive hypertension in individuals with impaired renal sodium excretion. Small guanosine triphosphatase (GTP)ase Rho and Rac, activated by salt intake, play important roles in the pathogenesis of salt-sensitive hypertension as key switches of intracellular signaling. Focusing on Rho, high salt intake in the central nervous system increases sodium concentrations of cerebrospinal fluid in salt-sensitive subjects via Rho/Rho kinase and renin-angiotensin system activation and causes increased brain salt sensitivity and sympathetic nerve outflow in BP control centers. In vascular smooth muscle cells, Rho-guanine nucleotide exchange factors and Rho determine sensitivity to vasoconstrictors such as angiotensin II (Ang II), and facilitate vasoconstriction via G-protein and Wnt pathways, leading to increased vascular resistance, including in the renal arteries, in salt-sensitive subjects with high salt intake. In the vascular endothelium, Rho/Rho kinase inhibits nitric oxide (NO) production and function, and high salt amounts further augment Rho activity via asymmetric dimethylarginine, an endogenous inhibitor of NO synthetase, causing aberrant relaxation and increased vascular tone. Rho-associated mechanisms are deeply involved in the development of salt-sensitive hypertension, and their further elucidation can help in developing effective protection and new therapies.

Adipocyte-Mineralocorticoid Receptor Alters Mitochondrial Quality Control Leading to Mitochondrial Dysfunction and Senescence of Visceral Adipose Tissue

Mineralocorticoid receptor (MR) expression is increased in the adipose tissue (AT) of obese patients and animals. We previously demonstrated that adipocyte-MR overexpression in mice (Adipo-MROE mice) is associated with metabolic alterations. Moreover, we showed that MR regulates mitochondrial dysfunction and cellular senescence in the visceral AT of obese db/db mice. Our hypothesis is that adipocyte-MR overactivation triggers mitochondrial dysfunction and cellular senescence, through increased mitochondrial oxidative stress (OS). Using the Adipo-MROE mice with conditional adipocyte-MR expression, we evaluated the specific effects of adipocyte-MR on global and mitochondrial OS, as well as on OS-induced damage. Mitochondrial function was assessed by high throughput respirometry. Molecular mechanisms were probed in AT focusing on mitochondrial quality control and senescence markers. Adipo-MROE mice exhibited increased mitochondrial OS and altered mitochondrial respiration, associated with reduced biogenesis and increased fission. This was associated with OS-induced DNA-damage and AT premature senescence. In conclusion, targeted adipocyte-MR overexpression leads to an imbalance in mitochondrial dynamics and regeneration, to mitochondrial dysfunction and to ageing in visceral AT. These data bring new insights into the MR-dependent AT dysfunction in obesity.

Mineralocorticoid receptors in the pathogenesis of insulin resistance and related disorders: from basic studies to clinical disease

Aldosterone is a steroid hormone that regulates blood pressure and cardiovascular function by acting on renal and vascular mineralocorticoid receptors (MRs) to promote sodium retention and modulate endothelial function. Indeed, MRs are expressed in endothelial cells, vascular smooth muscle cells, adipocytes, immune cells, skeletal muscle cells, and cardiomyocytes. Excessive aldosterone and associated MR activation impair insulin secretion, insulin metabolic signaling to promote development of diabetes, and the related cardiometabolic syndrome. These adverse effects of aldosterone are mediated, in part, via increased inflammation, oxidative stress, dyslipidemia, and ectopic fat deposition. Therefore, inhibition of MR activation may have a beneficial effect in prevention of impaired insulin metabolic signaling, type 2 diabetes, and cardiometabolic disorders. This review highlights findings from the recent surge in research regarding MR-related cardiometabolic disorders as well as our contemporary understanding of the detrimental effects of excess MR activation on insulin metabolic signaling.

How common is primary aldosteronism?

PURPOSE OF REVIEW

Primary aldosteronism, characterized by renin-independent aldosterone secretion from one or both adrenal glands, is the most common and modifiable form of secondary hypertension. The prevalence of primary aldosteronism is increasingly recognized to be much higher than previously thought with many cases still undetected.

RECENT FINDINGS

Prior prevalence studies on primary aldosteronism have reported a wide range of estimates due to heterogeneity of both disease definitions and study populations such that it is difficult to claim a single point estimate. More recent evidence demonstrates that primary aldosteronism, as defined by conventional biochemical diagnostic criteria, is highly prevalent within populations where it is not typically considered such as mild-to-moderate hypertension, prehypertension, and even normotension. Yet, our current screening approach fails to capture many cases. Furthermore, there is mounting evidence that renin-independent aldosteronism exists as a continuum of disease that extends below the current biochemical diagnostic thresholds used to define primary aldosteronsim and has clinically relevant treatment and outcome implications for a much broader patient population. Indeed, much of what we current label as 'essential hypertension' is, in fact, renin-independent aldosterone-mediated hypertension.

SUMMARY

Primary aldosteronism and milder forms of renin-independent aldosteronism are highly prevalent, yet vastly under-recognized, in the general population.

The Mineralocorticoid Receptor in Salt-Sensitive Hypertension and Renal Injury

Hypertension and its comorbidities pose a major public health problem associated with disease-associated factors related to a modern lifestyle, such high salt intake or obesity. Accumulating evidence has demonstrated that aldosterone and its receptor, the mineralocorticoid receptor (MR), have crucial roles in the development of salt-sensitive hypertension and coexisting cardiovascular and renal injuries. Accordingly, clinical trials have repetitively shown the promising effects of MR blockers in these diseases. We and other researchers have identified novel mechanisms of MR activation involved in salt-sensitive hypertension and renal injury, including the obesity-derived overproduction of aldosterone and ligand-independent signaling. Moreover, recent advances in the analysis of cell-specific and context-dependent mechanisms of MR activation in various tissues-including a classic target of aldosterone, aldosterone-sensitive distal nephrons-are now providing new insights. In this review, we summarize recent updates to our understanding of aldosterone-MR signaling, focusing on its role in salt-sensitive hypertension and renal injury.

The mineralocorticoid receptor-an emerging player in metabolic syndrome?

Metabolic syndrome is a cluster of conditions that increase the risk of cardiovascular diseases, and comprises obesity, hypertension, impaired glucose metabolism and dyslipidaemia. It is well recognised that the mineralocorticoid receptor (MR) plays an important role in blood pressure regulation via its effect on salt and water retention in renal tubules, with hypertension being a key feature in primary aldosteronism patients with excess adrenal production of aldosterone, the primary ligand for MRs in the epithelial tissues. MRs are also expressed in a number of non-epithelial tissues including adipose tissue; in these tissues, glucocorticoids or cortisol can also activate MRs due to low levels of 11-beta-hydroxysteroid-dehydrogenase type 2 (11-βHSD2), the enzyme which inactivates cortisol. There is increasing evidence suggesting that over-activation of MRs plays a role in the pathophysiology of the other components of metabolic syndrome, promoting adiposity, inflammation and glucose intolerance, and that MR antagonists may confer beneficial effects on energy and substrate homeostasis and cardiometabolic diseases. This review discusses the advances in the literature shedding light on the MR as an emerging player in metabolic syndrome.

Ventricular volume, white matter alterations and outcome of major depression and their relationship to endocrine parameters - A pilot study

OBJECTIVES

Brain morphology and its relation to endocrine parameters were examined, in order to determine the link of these parameters to treatment outcome to psychopharmacological treatment in depressed patients.

METHODS

We examined the potentially predictive value of Magnetic Resonance Imaging (MRI) parameters related to mineralocorticoid receptor (MR) function on the treatment outcome of depression. 16 inpatients with a major depressive episode (MDE) were studied at baseline and 14 of them approximately six weeks later. Physiological biomarkers and 3-T-structural MRI based volume measures, using FreeSurfer 6.0 software, were determined.

RESULTS

Non-responders (<50% reduction of HAMD-21; n = 6) had a significantly smaller volume of the right anterior cingulate cortex, a significantly larger ventricle to brain ratio (VBR) and third ventricle volume, and smaller volumes of the central and central-anterior corpus callosum (CC) in comparison to responders (n = 7; all p ≤ 0.05). Correlational analysis (Spearman) demonstrated that larger ventricle volume was correlated to a worse treatment outcome, higher body mass index (BMI) and smaller CC segment volume, whereas the total CC volume was negatively correlated to the saliva aldosterone/cortisol concentration ratio (AC-ratio).

CONCLUSION

Large ventricular volume may be a predictive marker for worse treatment response to standard antidepressant treatment, potentially via compression of white matter structures. A mediating role of the previously identified markers BMI and the AC-ratio, is suggested.

Bariatric Surgery Induces a Differential Effect on Plasma Aldosterone in Comparison to Dietary Advice Alone

BACKGROUND AND OBJECTIVES

The pathophysiological mechanisms linking weight loss to blood pressure (BP) reduction are not completely understood. The objective of this study was to compare the effect of weight loss after Roux-en-Y gastric bypass (RYGB) on BP, renin-angiotensin-aldosterone system (RAAS), and urinary electrolytes excretion to those of dietary advice.

METHODS

This was a case-control prospective study including obese patients referred for RYGB (cases) and obese receiving diet advice only (controls). Ambulatory BP, plasma renin activity (PRA), plasma aldosterone concentration (PAC), and urinary electrolytes were measured before (M0) and after intervention (M3: 3 months and M12: 12 months).

RESULTS

Twenty-five patients were included in the RYGB group and twelve patients in the control group. After 12 months, weight loss (-42 ± 11.5 vs -12.3 ± 6.3 kg in the control group, p=0.001) and decrease in PAC were more pronounced in the RYGB group (-34 ± 76 vs +14 ± 45 pg/ml in the control group, p=0.002). There was no difference in PRA between both groups (-0.08 ± 1.68 vs 0.01 ± 0.37 ng/ml/h, p=0.31). Sodium excretion was more marked in the RYGB group after 3 months only (-89 ± 14.9 vs -9.9 ± 27.9 mmol/day, p=0.009). The decrease in SBP was similar between both groups (-6.9 ± 9.9 vs -7.1 ± 11.9 mmHg in the control group, p=0.96).

CONCLUSIONS

Bariatric-induced weight loss induces a progressive decrease in PAC independently of PRA and sodium excretion. Whether this decrease in PAC affects target organ damage in the long term remains to be determined.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT02218112.

Association of the ratio of visceral-to-subcutaneous fat volume with renal function among patients with primary aldosteronism

Patients with primary aldosteronism have a higher risk of chronic kidney disease. Visceral fat tissue is hypothesized to stimulate the adrenal glands to overproduce aldosterone, and aldosterone promotes visceral fat tissue to produce inflammatory cytokines. However, it is unclear whether the volume of accumulated visceral fat tissue is associated with renal impairment among patients with hyperaldosteronism. We conducted a single-center cross-sectional study to assess the association between the estimated glomerular filtration rate and the ratio of the visceral-to-subcutaneous fat volume calculated by computed tomography. One hundred eighty patients with primary aldosteronism were enrolled. The mean ± SD age was 52.7 ± 11.0 years, and 60.0% were women. The ratio of visceral-to-subcutaneous fat volume was highly correlated with the estimated glomerular filtration rate (r = 0.49, p < 0.001). In multiple linear regression models, the ratio of visceral-to-subcutaneous fat tissue volume was significantly associated with the estimated glomerular filtration rate (estimates: -4.56 mL/min/1.73 m² per 1-SD), and there was an interaction effect between the plasma aldosterone concentration and the ratio of visceral-to-subcutaneous fat volume (p < 0.05). The group with a higher plasma aldosterone concentration exhibited a steeper decline in eGFR than the lower plasma aldosterone concentration group when the ratio increased. The ratio of visceral-to-subcutaneous fat tissue volume was an independent risk factor for renal dysfunction. This association increased in the presence of a high plasma aldosterone concentration. Clinicians should pay attention to the ratio of visceral-to-subcutaneous fat tissue volume and encourage primary aldosteronism patients to improve their lifestyle in addition to treating renin-aldosterone activity.

High body fat percentage is associated with primary aldosteronism: a cross-sectional study

BACKGROUND

Excess aldosterone has been shown to be associated with obesity; however, there is currently a lack of data regarding the relationship between percentage of body fat and primary aldosteronism (PA), particularly pertaining to Asian populations. Furthermore, essential hypertension may mimic the condition of PA and there needs to be differentiation between the two. This study aimed to assess the association between percentage of body fat and PA.

METHODS

A cross-sectional study was conducted in the outpatient department of the Endocrine and Metabolism Unit of the tertiary care medical center in Thailand. Data was obtained from 79 patients who had been screened for PA due to hypertension in young-onset, hypokalemia, adrenal incidentaloma or resistance hypertension. Essential hypertension was defined as patients who had high blood pressure and were negative for PA screening. Body fat percentage was assessed by bioelectrical impedance analysis. The relationship between percentage of body fat and a diagnosis of PA was assessed using logistic regression analysis, including adjustment for confounding factors.

RESULTS

The participants were divided into a PA group (n = 41) and an essential hypertension group (n = 38). After controlling for confounding variables (age, sex, body mass index, cholesterol and insulin resistance status), the odds ratio of having PA in males with a percentage of body fat > 25% and females with percentage > 30% was 1.82 (95%CI = 1.79-1.86, p < 0.001).

CONCLUSION

A higher percentage of body fat is associated with an increased risk of PA. Further studies need to be conducted to confirm the relationship between body fat percentage and PA.

Insulin and obesity transform hypothalamic-pituitary-adrenal axis stemness and function in a hyperactive state

Objective

Metabolic diseases are an increasing problem in society with the brain-metabolic axis as a master regulator of the human body for sustaining homeostasis under metabolic stress. However, metabolic inflammation and disease will trigger sustained activation of the hypothalamic-pituitary-adrenal axis. In this study, we investigated the role of metabolic stress on progenitor cells in the hypothalamic-pituitary-adrenal axis.

Methods

In vitro, we applied insulin and leptin to murine progenitor cells isolated from the pituitary and adrenal cortex and examined the role of these hormones on proliferation and differentiation. In vivo, we investigated two different mouse models of metabolic disease, obesity in leptin-deficient ob/ob mice and obesity achieved via feeding with a high-fat diet.

Results

Insulin was shown to lead to enhanced proliferation and differentiation of both pituitary and adrenocortical progenitors. No alterations in the progenitors were noted in our chronic metabolic stress models. However, hyperactivation of the hypothalamic-pituitary-adrenal axis was observed and the expression of the appetite-regulating genes Npy and Agrp changed in both the hypothalamus and adrenal.

Conclusions

It is well-known that chronic stress and stress hormones such as glucocorticoids can induce metabolic changes including obesity and diabetes. In this article, we show for the first time that this might be based on an early sensitization of stem cells of the hypothalamic-pituitary-adrenal axis. Thus, pituitary and adrenal progenitor cells exposed to high levels of insulin are metabolically primed to a hyper-functional state leading to enhanced hormone production. Likewise, obese animals exhibit a hyperactive hypothalamic-pituitary-adrenal axis leading to adrenal hyperplasia. This might explain how stress in early life can increase the risk for developing metabolic syndrome in adulthood.

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Insulin enhances proliferation and differentiation of adrenocortical and pituitary progenitors.

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Obesity leads to hyperactivation and priming of the HPA axis.

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Obesity leads to overexpression of appetite-regulating genes in the hypothalamus.

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Obesity leads to a decrease in the expression of appetite-regulating genes in the adrenal gland.

The potential pathophysiological role of aldosterone and the mineralocorticoid receptor in anxiety and depression - Lessons from primary aldosteronism

High levels of aldosterone appear to be related to depressive and anxiety related behavior as demonstrated in therapy refractory depression and primary aldosteronism (PA). We analyzed data from a large register of patients with PA in order to clarify mediators and moderators of this influence. Up to 624 subjects were analyzed, however not all subjects had a complete dataset. Due to the known gender differences in subjects with PA we performed the analyses adjusted for gender. We compared subjects with (PHQ-9 ≥ 5) vs. no depressive symptomatology. 56% of men and 61% of women met this depression criterion. In women aldosterone concentration was significantly higher in depressed patients and renin levels were significantly increased with higher anxiety scores. This was not found in men. Depressive symptoms in men and women were significantly associated to BMI (men: dep vs non-dep: 29.6 vs. 28.4, p < 0.05; women: 26.9 vs. 24.5) and body weight (p < 0.05). Neither blood pressure nor electrolytes were different between depression groups. The relationship of these parameters to anxiety was less pronounced and partially unexpected: only in men higher anxiety (GAD ≥ 5) was related to lower systolic blood pressure. In conclusion, higher aldosterone appears to be associated with depressive symptoms in women, but less so in men with PA. BMI appears to be strongly and independently associated with depressive symptoms in patients with PA, independent of gender. Further studies are required to clarify the causal relationship.

Salt-sensitive hypertension in chronic kidney disease: distal tubular mechanisms

Chronic kidney disease (CKD) causes salt-sensitive hypertension that is often resistant to treatment and contributes to the progression of kidney injury and cardiovascular disease. A better understanding of the mechanisms contributing to salt-sensitive hypertension in CKD is essential to improve these outcomes. This review critically explores these mechanisms by focusing on how CKD affects distal nephron Na+ reabsorption. CKD causes glomerulotubular imbalance with reduced proximal Na+ reabsorption and increased distal Na+ delivery and reabsorption. Aldosterone secretion further contributes to distal Na+ reabsorption in CKD and is not only mediated by renin and K+ but also by metabolic acidosis, endothelin-1, and vasopressin. CKD also activates the intrarenal renin-angiotensin system, generating intratubular angiotensin II to promote distal Na+ reabsorption. High dietary Na+ intake in CKD contributes to Na+ retention by aldosterone-independent activation of the mineralocorticoid receptor mediated through Rac1. High dietary Na+ also produces an inflammatory response mediated by T helper 17 cells and cytokines increasing distal Na+ transport. CKD is often accompanied by proteinuria, which contains plasmin capable of activating the epithelial Na+ channel. Thus, CKD causes both local and systemic changes that together promote distal nephron Na+ reabsorption and salt-sensitive hypertension. Future studies should address remaining knowledge gaps, including the relative contribution of each mechanism, the influence of sex, differences between stages and etiologies of CKD, and the clinical relevance of experimentally identified mechanisms. Several pathways offer opportunities for intervention, including with dietary Na+ reduction, distal diuretics, renin-angiotensin system inhibitors, mineralocorticoid receptor antagonists, and K+ or H+ binders.

Primary Aldosteronism and Obstructive Sleep Apnea: Casual Association or Pathophysiological Link?

The coexistence of aldosterone oversecretion and obstructive sleep apnea is frequently observed, especially in patients with resistant hypertension, obesity, and metabolic syndrome. Since aldosterone excess and sleep apnea are both independently associated with an increased risk of cardiovascular disease, to investigate whether their coexistence might be attributed to common predisposing conditions, such as metabolic disorders, or to an actual pathophysiological interconnection appears of great importance. Fluid overload and metabolic abnormalities relating to aldosterone oversecretion may be implicated in obstructive sleep apnea development. Nocturnal intermittent hypoxia may in turn exacerbate renin-angiotensin-aldosterone system activity, thus leading to hyperaldosteronism. Furthermore, fat tissue excess and adipocyte secretory products might predispose to both sleep apnea and aldosterone oversecretion in subjects with obesity. Consistent with these evidences, obstructive sleep apnea frequently affects patients with primary aldosteronism. Conversely, whether primary aldosteronism is more prevalent in individuals affected by obstructive sleep apnea compared to the general population remains controversial.

Management of primary aldosteronism and mineralocorticoid receptor-associated hypertension

Resistant hypertension is associated with a poor prognosis due to organ damage caused by prolonged suboptimal blood pressure control. The concomitant use of mineralocorticoid receptor (MR) antagonists with other antihypertensives has been shown to improve blood pressure control in some patients with resistant hypertension, and such patients are considered to have MR-associated hypertension. MR-associated hypertension is classified into two subtypes: one with a high plasma aldosterone level, which includes primary aldosteronism (PA), and the other with a normal aldosterone level. In patients with unilateral PA, adrenalectomy may be the first-choice procedure, while in patients with bilateral PA, MR antagonists are selected. In addition, in patients with other types of MR-associated hypertension with high aldosterone levels, MR antagonists may be selected as a first-line therapy. In patients with normal aldosterone levels, ARBs or ACE inhibitors are used as a first-line therapy, and MR antagonists may be used as an add-on agent. Since MR antagonist therapy may have efficacy as a first-line or add-on agent in these patients, it is important to recognize this type of hypertension. Further studies are needed to elucidate the pathogenesis and management of MR-associated hypertension in more detail to improve the clinical outcomes of patients with MR-associated hypertension.

Nanophytomedicines for the Prevention of Metabolic Syndrome: A Pharmacological and Biopharmaceutical Review

Metabolic syndrome includes a series of metabolic abnormalities that leads to diabetes mellitus and cardiovascular diseases. Plant extracts, due to their unique advantages like anti-inflammatory, antioxidant, and insulin sensitizing properties, are interesting therapeutic options to manage MetS; however, the poor solubility and low bioavailability of lipophilic bioactive components in the herbal extracts are two critical challenges. Nano-scale delivery systems are suitable to improve delivery of herbal extracts. This review, for the first time, focuses on nanoformulations of herbal extracts in MetS and related complications. Included studies showed that several forms of nano drug delivery systems such as nanoemulsions, solid lipid nanoparticles, nanobiocomposites, and green-synthesized silver, gold, and zinc oxide nanoparticles have been developed using herbal extracts. It was shown that the method of preparation and related parameters such as temperature and type of polymer are important factors affecting physicochemical stability and therapeutic activity of the final product. Many of these formulations could successfully decrease the lipid profile, inflammation, oxidative damage, and insulin resistance in in vitro and in vivo models of MetS-related complications. Further studies are still needed to confirm the safety and efficacy of these novel herbal formulations for clinical application.

Obesity Might Persistently Increase Adrenal Gland Volume: a Preliminary Study

OBJECTIVES

This study aimed to investigate the association of obesity with adrenal gland volume (AGV) and the effects of weight loss on AGV.

METHODS

This study included obese patients (N = 25) who underwent sleeve gastrectomy and age- and sex-matched healthy volunteers (HVs) (N = 25) and overweight healthy volunteers (overweight-HVs) (N = 21). Thin-slice computed tomography was used to evaluate adrenal morphological changes. AGV was measured semiautomatically based on the digital imaging and communications in medicine (DICOM) image. The effects of weight loss on AGV and adrenal gland density were evaluated in patients for 1 year or more after sleeve gastrectomy.

RESULTS

Left, right, and total AGV were 6.77 ± 0.36, 5.76 ± 0.31, and 12.53 ± 0.64 cm³ in obese patients, which were significantly higher than those in the overweight-HVs (3.88 ± 0.14, 3.09 ± 0.13, and 6.97 ± 0.24 cm³) and HVs (3.38 ± 0.23, 2.67 ± 0.15, and 6.04 ± 0.36 cm³). AGV was larger in overweight-HVs than in HVs, but no statistically significant difference was identified. Sleeve gastrectomy significantly reduced body weight (- 27.1 ± 2.5 kg), left AGV (- 0.80 ± 0.26 cm³), and right AGV (- 0.88 ± 0.20 cm²). The adrenal volume in five patients was not reduced, despite significant weight loss postsurgery. The mean density of adrenal glands was lower in obese patients (P = 0.025) but were not significantly increased postsurgery.

CONCLUSIONS

Obesity leads to increased AGV, and in some cases, this effect seems to be irreversible. The clinical implication of obesity-induced adrenal morphological changes needs to be studied further.

The Effects of Salt and Glucose Intake on Angiotensin II and Aldosterone in Obese and Nonobese Patients with Essential Hypertension

Background

The exact mechanisms for the development of essential hypertension are not known. Activation of the renin-angiotensin-aldosterone system (RAAS) in adipose tissue may represent an important link between obesity and hypertension. This study investigates the effects of oral intake of glucose with and without NaCl on angiotensin II (AngII) and aldosterone in obese and nonobese patients with essential hypertension.

Methods

Twenty newly diagnosed untreated essential hypertensive patients and 15 normotensive control subjects matched for age, gender, and BMI were studied. Participants fasted overnight (8–10 hrs), and then each subject took 75 gm glucose alone and with 3 gm NaCl, each dissolved in 250 ml. Subjects were monitored for 2 hours. Half hourly BP, plasma glucose (PG), serum Na⁺, K⁺, insulin, AngII, and aldosterone were measured. Subjects were classified into obese (BMI >30 Kg/m²) (11 patients and 8 control) and nonobese (BMI <30 Kg/m²) (9 patients and 7 control).

Results

After intake of glucose with NaCl serum, AngII was significantly higher in obese hypertensive patients compared with nonobese patients (P = 0.016). Intake of glucose with NaCl resulted in a significantly higher serum Na in obese hypertensive patients compared with nonobese patients Na (P = 0.009). Serum aldosterone was significantly higher in obese patients (P = 0.03, after glucose; P = 0.003, after glucose with NaCl) and in nonobese patients (P = 0.000 and P = 0.000, respectively) compared with their respective normotensive control subjects. In obese and nonobese patients, intake of glucose and glucose with NaCl showed no significant change in the levels of serum AngII and aldosterone which was associated a significant increase in serum Na in obese patients (P = 0.03) and a highly significant reduction in serum K in nonobese patients (P = 0.001).

Conclusion

Failure of suppression or inappropriate maintenance of secretion of AngII and aldosterone in both hypertensive groups by intake of glucose with NaCl may indicate a possible mechanism of essential hypertension.

Obesity-related hypertension: a review of pathophysiology, management, and the role of metabolic surgery

Obesity is a significant public health challenge worldwide and is inextricably linked to adverse cardiovascular outcomes. The relationship between excess adiposity and increased blood pressure is well established, and it is estimated that obesity accounts for 65-78% of cases of primary hypertension. The mechanisms through which obesity causes hypertension are complex and include sympathetic nervous system overactivation, stimulation of the renin-angiotensin-aldosterone system, alterations in adipose-derived cytokines, insulin resistance, and structural and functional renal changes. Weight loss is the primary goal of treatment for obesity-related hypertension, although few individuals achieve success with nonpharmacological management alone. Specific considerations apply when selecting the most appropriate pharmacological therapy for obese hypertensive patients. Metabolic surgery has proved to be the most effective means of ensuring substantial and sustained weight loss and has also been shown to confer beneficial effects in type 2 diabetes mellitus. Increasing evidence suggests that metabolic surgery may also be an effective treatment for obesity-related hypertension, although prospective data on long-term blood pressure outcomes are awaited. This review will discuss the pathophysiological mechanisms that link obesity with hypertension and will provide an overview of treatment strategies, with a focus on metabolic surgery.

Effects of Adipocyte-derived Factors on the Adrenal Cortex

Background and Objective:

Obesity is highly complicated by hypertension and hyperglycemia. In particular, it has been proposed that obesity-related hypertension is caused by adipocyte-derived factors that are recognized as undetermined proteins secreted from adipocytes. Adipocyte-derived factors have been known to be related to aldosterone secretion in the adrenal gland. So far, Wnt proteins, CTRP-1, VLDL, LDL, HDL and leptin have been demonstrated to stimulate aldosterone secretion. In contrast, it has not yet been clarified whether adipocyte-derived factors also affect adrenal cortisol secretion.

Methods and Results:

In the present study, we investigated the effect of adipocyte-derived factors on cortisol synthase gene CYP11B1 mRNA expression in vitro study using adrenocortical carcinoma H295R cells and mouse fibroblast 3T3-L1cells. Interestingly, adipocyte-derived factors were demonstrated to have the ability to stimulate CYP11B1 mRNA expression.

Conclusion:

Since CYP11B1 is well known as a limiting enzyme of cortisol synthesis, our study suggests that adipocyte-derived factors may stimulate cortisol secretion, as well as aldosterone secretion. Taken together, adipocyte-derived factors may be the cause of metabolic syndrome due to their stimulating effects on aldosterone/cortisol secretion. Therefore, the innovation of novel drugs against them may possibly be a new approach against metabolic syndrome.

Treatment of Resistant and Refractory Hypertension

Resistant hypertension (RHTN) is defined as uncontrolled blood pressure despite the use of ≥3 antihypertensive agents of different classes, including a diuretic, usually thiazide-like, a long-acting calcium channel blocker, and a blocker of the renin- angiotensin system, either an ACE (angiotensin-converting enzyme) inhibitor or an ARB (angiotensin receptor blocker), at maximal or maximally tolerated doses. Antihypertensive medication nonadherence and the white coat effect, defined as elevated blood pressure when measured in clinic but controlled when measured outside of clinic, must be excluded to make the diagnosis. RHTN is a high-risk phenotype, leading to increased all-cause mortality and cardiovascular disease outcomes. Healthy lifestyle habits are associated with reduced cardiovascular risk in patients with RHTN. Aldosterone excess is common in patients with RHTN, and addition of spironolactone or amiloride to the standard 3-drug antihypertensive regimen is effective at getting the blood pressure to goal in most of these patients. Refractory hypertension is defined as uncontrolled blood pressure despite use of ≥5 antihypertensive agents of different classes, including a long-acting thiazide-like diuretic and an MR (mineralocorticoid receptor) antagonist, at maximal or maximally tolerated doses. Fluid retention, mediated largely by aldosterone excess, is the predominant mechanism underlying RHTN, while patients with refractory hypertension typically exhibit increased sympathetic nervous system activity.

Obesity-Associated Heart Failure as a Theoretical Target for Treatment With Mineralocorticoid Receptor Antagonists

Importance

Despite their clinical benefits, mineralocorticoid receptor antagonists are greatly underprescribed by most practitioners who treat patients with chronic heart failure. A novel approach to encouraging the use of these drugs is to enhance awareness about the intimate link between aldosterone and obesity.

Observations

There is a strong association between abdominal obesity and circulating levels of aldosterone, and markers of abdominal obesity identify patients most likely to benefit from mineralocorticoid receptor antagonism. In a trial of patients with heart failure and a reduced ejection fraction, patients with an increased waist circumference exhibited an approximately 50% reduction in the risk of a primary end point. The magnitude of benefit was more than twice as great in patients with abdominal obesity than in those with a normal waist circumference, and patients with abdominal obesity tolerated treatment better than nonobese patients. Similarly, in a trial of patients with heart failure and a preserved ejection fraction, those who were most likely to have abdominal obesity (identified by their level of natriuretic peptides) were most likely to demonstrate a benefit of treatment with spironolactone, exhibiting an approximately 80% reduction in the risk of a primary end point (based on a small number of events).

Conclusions and Relevance

Although these analyses are post hoc, their concordance and strong biological foundation suggests that abdominal obesity may identify patients who respond most favorably to mineralocorticoid receptor antagonism. Given the easy availability of its measurement, targeting patients with an increased waist circumference could enhance the adoption of these important drugs for the treatment of chronic heart failure in clinical practice.