Modulation of Immunity and Inflammation by the Mineralocorticoid Receptor and Aldosterone

Ex Vivo 13C-Metabolic Flux Analysis of Porcine Circulating Immune Cells Reveals Cell Type-Specific Metabolic Patterns and Sex Differences in the Pentose Phosphate Pathway

In general, females present with stronger immune responses than males, but scarce data are available on sex-specific differences in immunometabolism. In this study, we characterized porcine peripheral blood mononuclear cell (PBMC) and granulocyte energy metabolism using a Bayesian 13C-metabolic flux analysis, which allowed precise determination of the glycolytic, pentose phosphate pathway (PPP), and tricarboxylic acid cycle (TCA) fluxes, together with an assessment of the superoxide anion radical (O2•-) production and mitochondrial O2 consumption. A principal component analysis allowed for identifying the cell type-specific patterns of metabolic plasticity. PBMCs displayed higher TCA cycle activity, especially glutamine-derived aspartate biosynthesis, which was directly related to mitochondrial respiratory activity and inversely related to O2•- production. In contrast, the granulocytes mainly utilized glucose via glycolysis, which was coupled to oxidative PPP utilization and O2•- production rates. The granulocytes of the males had higher oxidative PPP fluxes compared to the females, while the PBMCs of the females displayed higher non-oxidative PPP fluxes compared to the males associated with the T helper cell (CD3+CD4+) subpopulation of PBMCs. The observed sex-specific differences were not directly attributable to sex steroid plasma levels, but we detected an inverse correlation between testosterone and aldosterone plasma levels and showed that aldosterone levels were related with non-oxidative PPP fluxes of both cell types.

Cognitive Changes Associated with Aging and Physical Disease in Dogs and Cats

Behavior changes may indicate primary physical disease or primary behavioral disorders in veterinary patients. It is imperative to recognize that secondary behavioral problems can develop due to medical causes. The incidence of systemic disease increases with age and behavior manifestations can be similar to those expected with cognitive dysfunction syndrome. In this article, we review basic concepts of cognition, aging, and cognitive dysfunction syndrome. Additionally, we provide information regarding factors that influence cognition, and the role medical conditions have on the behavior of aging pets.

Tubular injury in diabetic kidney disease: molecular mechanisms and potential therapeutic perspectives

Diabetic kidney disease (DKD) is a chronic complication of diabetes and the leading cause of end-stage renal disease (ESRD) worldwide. Currently, there are limited therapeutic drugs available for DKD. While previous research has primarily focused on glomerular injury, recent studies have increasingly emphasized the role of renal tubular injury in the pathogenesis of DKD. Various factors, including hyperglycemia, lipid accumulation, oxidative stress, hypoxia, RAAS, ER stress, inflammation, EMT and programmed cell death, have been shown to induce renal tubular injury and contribute to the progression of DKD. Additionally, traditional hypoglycemic drugs, anti-inflammation therapies, anti-senescence therapies, mineralocorticoid receptor antagonists, and stem cell therapies have demonstrated their potential to alleviate renal tubular injury in DKD. This review will provide insights into the latest research on the mechanisms and treatments of renal tubular injury in DKD.

The Correlation Between Aldosterone and Leukocyte-Related Inflammation: A Comparison Between Patients with Primary Aldosteronism and Essential Hypertension

Background

Hypertension patients with primary aldosteronism (PA) have a higher risk of cardiovascular complications than blood pressure-matched essential hypertension (EH) patients. The cause may be closely related to inflammation. We explored the correlations between leukocyte-related inflammation parameters and plasma aldosterone concentration (PAC) in PA patients and clinical characteristics-matched EH patients.

Methods

A total of 346 PA and 346 sex, age and 24-h blood pressure-matched EH patients at the 2nd Affiliated Hospital of Nanchang University from January 2020 to June 2021 were enrolled in this study. The differences and correlations of aldosterone and leukocyte parameters between the two groups were analyzed.

Results

Compared with EH patients, the lymphocyte count was significantly lower (P = 0.004), the neutrophil-lymphocyte ratio (NLR) (P = 0.023) and the monocyte-lymphocyte ratio (MLR) (P = 0.037) were significantly higher in PA patients. Linear regression analysis and multivariate regression analysis identified that lymphocyte count, NLR and MLR were significantly and independently correlated with PAC in PA patients, and the correlations were stronger with increasing levels of aldosterone. However, in EH patients, only NLR maintained an independent correlation with PAC.

Conclusion

Leukocyte-related inflammation parameters, including lymphocyte count, NLR, and MLR, were significantly and independently correlated with PAC in PA patients. The correlations were stronger with increasing levels of aldosterone. However, the above correlations were not always present in patients with EH matched for clinical characteristics.

The epithelial sodium channel in inflammation and blood pressure modulation

A major regulator of blood pressure and volume homeostasis in the kidney is the epithelial sodium channel (ENaC). ENaC is composed of alpha(α)/beta(β)/gamma(γ) or delta(δ)/beta(β)/gamma(γ) subunits. The δ subunit is functional in the guinea pig, but not in routinely used experimental rodent models including rat or mouse, and thus remains the least understood of the four subunits. While the δ subunit is poorly expressed in the human kidney, we recently found that its gene variants are associated with blood pressure and kidney function. The δ subunit is expressed in the human vasculature where it may influence vascular function. Moreover, we recently found that the δ subunit is also expressed human antigen presenting cells (APCs). Our studies indicate that extracellular Na+ enters APCs via ENaC leading to inflammation and salt-induced hypertension. In this review, we highlight recent findings on the role of extra-renal ENaC in inflammation, vascular dysfunction, and blood pressure modulation. Targeting extra-renal ENaC may provide new drug therapies for salt-induced hypertension.

Relationships between hormone levels, metabolism and immune response in toads from a semi-arid region

Steroid hormones (e.g. androgens [AN] and corticosterone [CORT]) modulate complex physiological functions such as reproduction, energy mobilization, metabolism, and immunity. Fluctuations in environmental resource availability along with other factors, such as parasitism, can interact with the effects of these steroids, modifying aspects of immunocompetence and its metabolic costs. To understand these possible interactions, we studied AN and CORT, immune response [swelling response to phytohemagglutinin (PHA) injection and bacterial killing ability (BKA)], parasite load, resting metabolic rate (RMR) and rates of oxygen consumption after PHA injection, in two different phases of the annual cycle of a toad (Rhinella jimi) from a highly seasonal environment (Brazilian semi-arid, Caatinga). We observed increased rates of O₂ consumption after both PHA and the control (saline) injection, indicating a metabolic response to adverse stimuli but not the immune challenge. Toads showing higher RMR and VO₂ after the adverse stimuli (PHA/saline injection) had lower field AN and CORT plasma levels, suggesting these hormones might mediate a metabolic energy conservation strategy both at baseline levels and after adverse stimuli. Parasite load seem to impose an energetic constrain to the metabolic response to PHA and saline injection. Also, individuals showing higher PHA swelling response had higher field CORT plasma levels (particularly when males are breeding) which opposes the idea of a possible trade-off between reproductive activity and other physiological traits and indicate the immunoenhancing effects CORT elevated at physiological levels. BKA did not show a seasonal variation or correlation with body condition nor hormone levels, indicating that the immune surveillance mediated by the complement remains constant despite other ecological and physiological changes.

Renal Protection of Mineralocorticoid Receptor Antagonist, Finerenone, in Diabetic Kidney Disease

Chronic kidney disease (CKD) is the most common cause of end-stage renal disease in patients with type 2 diabetes mellitus (T2DM). CKD increases the risk of cardiovascular diseases; therefore, its prevention and treatment are important. The prevention of diabetic kidney disease (DKD) can be achieved through intensive glycemic control and blood pressure management. Additionally, DKD treatment aims to reduce albuminuria and improve kidney function. In patients with T2DM, renin-angiotensin-aldosterone system inhibitors, sodium glucose cotransporter 2 inhibitors, and glucagon-like peptide-1 receptor agonists can delay the progression of DKD. Hence, there is a need for novel treatments that can effectively suppress DKD progression. Finerenone is a first-in-class nonsteroidal mineralocorticoid receptor antagonist with clinically proven efficacy in improving albuminuria, estimated glomerular filtration rate, and risk of cardiovascular events in early and advanced DKD. Therefore, finerenone is a promising treatment option to delay DKD progression. This article reviews the mechanism of renal effects and major clinical outcomes of finerenone in DKD.

Importance of Micromilieu for Pathophysiologic Mineralocorticoid Receptor Activity—When the Mineralocorticoid Receptor Resides in the Wrong Neighborhood

The mineralocorticoid receptor (MR) is a member of the steroid receptor family and acts as a ligand-dependent transcription factor. In addition to its classical effects on water and electrolyte balance, its involvement in the pathogenesis of cardiovascular and renal diseases has been the subject of research for several years. The molecular basis of the latter has not been fully elucidated, but an isolated increase in the concentration of the MR ligand aldosterone or MR expression does not suffice to explain long-term pathologic actions of the receptor. Several studies suggest that MR activity and signal transduction are modulated by the surrounding microenvironment, which therefore plays an important role in MR pathophysiological effects. Local changes in micromilieu, including hypoxia, ischemia/reperfusion, inflammation, radical stress, and aberrant salt or glucose concentrations affect MR activation and therefore may influence the probability of unphysiological MR actions. The surrounding micromilieu may modulate genomic MR activity either by causing changes in MR expression or MR activity; for example, by inducing posttranslational modifications of the MR or novel interaction with coregulators, DNA-binding sites, or non-classical pathways. This should be considered when developing treatment options and strategies for prevention of MR-associated diseases.

Role of Finerenone in the Treatment of Diabetic Kidney Disease: Patient Selection and Clinical Perspectives

Diabetes is the leading cause of chronic and end stage kidney disease globally. Despite recent advances in therapies for diabetic kidney disease (DKD), there remains a critical need for additional options to improve renal and cardiovascular outcomes. Mineralocorticoid overactivation contributes to inflammation and fibrosis which in turn leads to progression of DKD. Finerenone, a novel non-steroidal mineralocorticoid receptor antagonist, has shown promising cardiac and renoprotective benefits in DKD. The utility of finerenone in the real world will require appropriate patient selection and patient monitoring by clinicians.

Divergent Characteristics of T-Cell Receptor Repertoire Between Essential Hypertension and Aldosterone-Producing Adenoma

Aldosterone-producing adenoma (APA) is a benign adrenal tumor that results in persistent hyperaldosteronism. As one major subtype of primary aldosteronism, APA leads to secondary hypertension that is associated with immune dysregulation. However, how the adaptive immune system, particularly the T-cell population, is altered in APA patients remains largely unknown. Here, we performed TCR sequencing to characterize the TCR repertoire between two age-matched groups of patients: one with APA and the other one with essential hypertension (EH). Strikingly, we found a significant reduction of TCR repertoire diversity in the APA group. Analyses on TCR clustering and antigen annotation further showed that the APA group possessed lower diversity in TCR clonotypes with non-common antigen-specific features, compared with the EH group. In addition, our results indicated that the strength of correlation between generation probabilities and frequencies of TCR clonotypes was significantly higher in the APA group than that in the EH group. Finally, we observed that clinical features, including plasma aldosterone level, aldosterone–renin ratio, and blood sodium level, were positively associated with the strength of correlation between generation and abundance of TCR clonotypes in the APA group. Our findings unveiled the correlation between T-cell immune repertoire and APA, suggesting a critical role of such adrenal adenoma in the T-cell immunity of patients with hypertension.

Homeostatic Regulation of Glucocorticoid Receptor Activity by Hypoxia-Inducible Factor 1: From Physiology to Clinic

Glucocorticoids (GCs) represent a well-known class of lipophilic steroid hormones biosynthesised, with a circadian rhythm, by the adrenal glands in humans and by the inter-renal tissue in teleost fish (e.g., zebrafish). GCs play a key role in the regulation of numerous physiological processes, including inflammation, glucose, lipid, protein metabolism and stress response. This is achieved through binding to their cognate receptor, GR, which functions as a ligand-activated transcription factor. Due to their potent anti-inflammatory and immune-suppressive action, synthetic GCs are broadly used for treating pathological disorders that are very often linked to hypoxia (e.g., rheumatoid arthritis, inflammatory, allergic, infectious, and autoimmune diseases, among others) as well as to prevent graft rejections and against immune system malignancies. However, due to the presence of adverse effects and GC resistance their therapeutic benefits are limited in patients chronically treated with steroids. For this reason, understanding how to fine-tune GR activity is crucial in the search for novel therapeutic strategies aimed at reducing GC-related side effects and effectively restoring homeostasis. Recent research has uncovered novel mechanisms that inhibit GR function, thereby causing glucocorticoid resistance, and has produced some surprising new findings. In this review we analyse these mechanisms and focus on the crosstalk between GR and HIF signalling. Indeed, its comprehension may provide new routes to develop novel therapeutic targets for effectively treating immune and inflammatory response and to simultaneously facilitate the development of innovative GCs with a better benefits-risk ratio.

Mineralocorticoid Receptor in Myeloid Cells Mediates Angiotensin II-Induced Vascular Dysfunction in Female Mice

Enhanced mineralocorticoid receptor (MR) signaling is critical to the development of endothelial dysfunction and arterial stiffening. However, there is a lack of knowledge about the role of MR-induced adipose tissue inflammation in the genesis of vascular dysfunction in women. In this study, we hypothesize that MR activation in myeloid cells contributes to angiotensin II (Ang II)-induced aortic stiffening and endothelial dysfunction in females via increased pro-inflammatory (M1) macrophage polarization. Female mice lacking MR in myeloid cells (MyMRKO) were infused with Ang II (500 ng/kg/min) for 4 weeks. This was followed by determinations of aortic stiffness and vasomotor responses, as well as measurements of markers of inflammation and macrophage infiltration/polarization in different adipose tissue compartments. MyMRKO mice were protected against Ang II-induced aortic endothelial stiffening, as assessed via atomic force microscopy in aortic explants, and vasorelaxation dysfunction, as measured by aortic wire myography. In alignment, MyMRKO mice were protected against Ang II-induced macrophage infiltration and M1 polarization in visceral adipose tissue (VAT) and thoracic perivascular adipose tissue (tPVAT). Collectively, this study demonstrates a critical role of MR activation in myeloid cells in the pathogenesis of vascular dysfunction in females associated with pro-inflammatory macrophage polarization in VAT and tPVAT. Our data have potential clinical implications for the prevention and management of cardiovascular disease in women, who are disproportionally at higher risk for poor outcomes.

A Mineralocorticoid Receptor Deficiency in Myeloid Cells Reduces Liver Steatosis by Impairing Activation of CD8+ T Cells in a Nonalcoholic Steatohepatitis Mouse Model

Background and Aims

The mineralocorticoid receptor (MR) and renin-angiotensin-aldosterone system (RAAS) are implicated in non-alcoholic liver fatty disease (NALFD). However, inflammatory mechanisms linking MR and RAAS with disease pathology remain unclear. Here we aimed to evaluate the contribution of myeloid MR to the inflammatory response in an animal model of non-alcoholic steatohepatitis (NASH), induced with a methionine-choline deficient diet (MCD).

Methods

Mice with a conditional deficiency of MR in myeloid cells (MyMRKO) and their counterpart floxed control mice (FC) were fed for 18 days with MCD or chow diet, respectively. Serum levels of aminotransferases and aldosterone levels were measured and hepatic steatosis, inflammation and fibrosis scored histologically. Hepatic triglyceride content (HTC) and hepatic mRNA levels of pro-inflammatory pro-fibrotic-associated genes were also assessed. Deep flow cytometric analysis was used to dissect the immune response during NASH development.

Results

MyMRKO mice fed with an MCD diet exhibited reduced hepatic inflammation and lower HTC than controls. Absolute number and percentage of liver inflammatory infiltrate cells (except for CD8⁺ T lymphocytes) were similar in both MyMRKO and control mice fed with an MCD diet but expression of the costimulatory molecule CD86 by dendritic cells and the CD25 activation marker in CD8⁺ T cells were significantly reduced in MyMRKO.

Conclusions

Proinflammatory cells are functionally suppressed in the absence of MR. We hypothesized that loss of MR in myeloid cells reduces lipid accumulation in the liver, in part through modulating the adaptive immune response, which is pivotal for the development of steatosis.

Genetic renal disease classification by hormonal axes

The kidneys, which regulate many homeostatic pathways, are also a major endocrinological target organ. Many genetic renal diseases can be classified according to the affected protein along such endocrinological pathways. In this review, we examine the hypothesis that a more severe phenotype is expected as the affected protein is located more distally along such pathways. Thus, the location of a defect along its endocrinological pathway should be taken into consideration, in addition to the mutation type, when assessing genetic renal disease severity.

A Multicenter Study of Neutrophil-to-Lymphocyte Ratio in Primary Aldosteronism

Background

Hypertensive patients with primary aldosteronism (PA) have a higher risk of cardiovascular complications than those with blood pressure-matched essential hypertension. The excess cardiovascular consequences of PA can be attributed to the proinflammatory effect of excessive aldosterone and mineralocorticoid receptor activation in a range of peripheral tissues and cell types. The neutrophil-to-lymphocyte ratio (NLR) is a widely available marker of inflammation which has been shown to predict cardiovascular outcome in the general population. This study aims to evaluate the use of NLR as a potential biomarker of PA and PA severity.

Methods

Patients with PA (n = 355) were identified from 2 large PA databases in Australia and China, while controls (n = 222) were patients with hypertension who were referred for assessment but did not meet the diagnostic criteria for PA. The NLR was retrospectively collected from routine full blood examination, prior to commencement of targeted treatment for PA.

Results

The NLR did not differ between PA patients and hypertensive controls (median 2.3 and 2.4, P = 0.563). However, among patients with PA, the NLR was positively correlated with baseline and post-saline aldosterone levels (r = 0.22 and P < 0.001 for both) and negatively correlated with serum potassium (r = -0.15, P = 0.006). Furthermore, in a logistic regression analysis of data from patients with PA, the NLR predicted the presence of comorbid chronic kidney disease (CKD) (defined as estimated glomerular filtration rate <60 mL/min/1.73m²) with an odds ratio of 1.5 (P = 0.003).

Conclusion

While the NLR did not distinguish PA from controls, it was a marker of PA severity, being associated with aldosterone concentration as well as the presence of CKD. A prospective study is needed to further clarify the role of NLR in predicting end-organ damage associated with PA.

Regulation of the germinal center response by nuclear receptors and implications for autoimmune diseases

The immune system plays an essential role in protecting the host from infectious diseases and cancer. Notably, B and T lymphocytes from the adaptive arm of the immune system can co-operate to form long-lived antibody responses and are therefore the main target in vaccination approaches. Nevertheless, protective immune responses must be tightly regulated to avoid hyper-responsiveness and responses against self that can result in autoimmunity. Nuclear receptors (NRs) are perfectly adapted to rapidly alter transcriptional cellular responses to altered environmental settings. Their functional role is associated with both immune deficiencies and autoimmunity. Despite extensive linking of nuclear receptor function with specific CD4 T helper subsets, research on the functional roles and mechanisms of specific NRs in CD4 follicular T helper cells (Tfh) and germinal center (GC) B cells during the germinal center reaction is just emerging. We review recent advances in our understanding of NR regulation in specific cell types of the GC response and discuss their implications for autoimmune diseases such as systemic lupus erythematosus (SLE).

Altered Tregs Differentiation and Impaired Autophagy Correlate to Atherosclerotic Disease

Atherosclerosis is a progressive vascular disease representing the primary cause of morbidity and mortality in developed countries. Formerly, atherosclerosis was considered as a mere passive accumulation of lipids in blood vessels. However, it is now clear that atherosclerosis is a complex and multifactorial disease, in which the involvement of immune cells and inflammation play a key role. A variety of studies have shown that autophagy-a cellular catalytic mechanism able to remove injured cytoplasmic components in response to cellular stress-may be proatherogenic. So far, in this context, its role has been investigated in smooth muscle cells, macrophages, and endothelial cells, while the function of this catabolic protective process in lymphocyte functionality has been overlooked. The few studies carried out so far, however, suggested that autophagy modulation in lymphocyte subsets may be functionally related to plaque formation and development. Therefore, in this research, we aimed at better clarifying the role of lymphocyte subsets, mainly regulatory T cells (Tregs), in human atherosclerotic plaques and in animal models of atherosclerosis investigating the contribution of autophagy on immune cell homeostasis. Here, we investigate basal autophagy in a mouse model of atherosclerosis, apolipoprotein E (ApoE)-knockout (KO) mice, and we analyze the role of autophagy in driving Tregs polarization. We observed defective maturation of Tregs from ApoE-KO mice in response to tumor growth factor-β (TGFβ). TGFβ is a well-known autophagy inducer, and Tregs maturation defects in ApoE-KO mice seem to be related to autophagy impairment. In this work, we propose that autophagy underlies Tregs maturation, advocating that the study of this process in atherosclerosis may open new therapeutic strategies.

A Jack of All Trades: Impact of Glucocorticoids on Cellular Cross-Talk in Osteoimmunology

Glucocorticoids (GCs) are known to have a strong impact on the immune system, metabolism, and bone homeostasis. While these functions have been long investigated separately in immunology, metabolism, or bone biology, the understanding of how GCs regulate the cellular cross-talk between innate immune cells, mesenchymal cells, and other stromal cells has been garnering attention rather recently. Here we review the recent findings of GC action in osteoporosis, inflammatory bone diseases (rheumatoid and osteoarthritis), and bone regeneration during fracture healing. We focus on studies of pre-clinical animal models that enable dissecting the role of GC actions in innate immune cells, stromal cells, and bone cells using conditional and function-selective mutant mice of the GC receptor (GR), or mice with impaired GC signaling. Importantly, GCs do not only directly affect cellular functions, but also influence the cross-talk between mesenchymal and immune cells, contributing to both beneficial and adverse effects of GCs. Given the importance of endogenous GCs as stress hormones and the wide prescription of pharmaceutical GCs, an improved understanding of GC action is decisive for tackling inflammatory bone diseases, osteoporosis, and aging.

Redefining the perioperative stress response: a narrative review

The systemic stress response triggered by surgical trauma is characterised by sterile inflammation preceding metabolic and neuroendocrine dysregulation. However, the relevance of the classically described 'stress response' is now highly questionable in an era where profound physiological deconditioning is common in older, frail surgical patients. Commonly used assessment techniques do not accurately reflect hypothalamic-pituitary-adrenal axis integrity after major surgery. Clinical interpretation of plasma concentrations of cortisol, the prototypical stress hormone, is rarely accurate, because of study heterogeneity, the inherently dynamic characteristics of cortisol production, and assay variability. Before surgery, chronic psychosocial stress and common cardiorespiratory co-morbidities are clinically relevant modifiers of neuroendocrine activation to acute stress/inflammation. The frequent development of multi-morbidity after major surgery further clouds the compartmentalised, discrete model of neuroendocrine activation after initial tissue injury. Starvation, impaired mobility, and sepsis after surgery generate distinct neuroendocrine profiles that challenge the conventional model of neuroendocrine activation. Basic science studies suggest that high circulating levels of cortisol may directly cause organ injury. Conversely, randomised controlled clinical trials investigating glucocorticoid supplementation have delivered contrasting results, with some suggesting a protective effect in the perioperative period. Here, we consider many of the confounding factors that have emerged to challenge the conventional model of the surgical stress response, and suggest that a more nuanced understanding of changes in hypothalamic-pituitary-adrenal axis physiology is warranted to advance perioperative medicine. Re-examining the perioperative stress response presents opportunities for improving outcomes through enhancing the understanding of the neuroendocrine aspects of preparation for and recovery from surgery.

Inhibitory Effects of Oxymatrine on Transdifferentiation of Neonatal Rat Cardiac Fibroblasts to Myofibroblasts Induced by Aldosterone via Keap1/Nrf2 Signaling Pathways In Vitro

Background

Oxymatrine (OMT), a quinolizidine alkaloid derived from the traditional Chinese herb Radix Sophorae flavescentis, has widely reported pharmacological efficacy in treating cardiovascular dysfunction-related diseases. However, the underlying mechanism has been unclear. Here, we investigated the potential inhibitory effects and mechanism of OMT on transdifferentiation of cardiac fibroblast to myofibroblasts induced by aldosterone in vitro.

Material/Methods

The cardiac fibroblasts (CFBs) proliferation and migration capacity were evaluated by MTT assay, cell cycle assay, and scratch analysis, respectively. The protein expression of the Nrf2/Keap1 signal pathway, FN, Collagen I, Collagen III, α-SMA, CTGF, and mineralocorticoid receptor (MR) protein was detected by Western blot analysis. The mRNA expression of Nrf2 was detected by qRT-PCR. Immunofluorescence staining was used to observe the expression of α-SMA protein. Nrf2 siRNA was used to explore the role of Nrf2 in OMT-treated CFBs. GSH, SOD, and MDA levels and hydroxyproline content were measured by colorimetric assay with commercial kits. The DCFH-DA fluorescent probe was used to assess cellular ROS levels.

Results

OMT and Curcumin (an Nrf2 agonist) attenuated aldosterone (ALD)-induced proliferation and migration in CFBs, as well as the fibrosis-associated protein expression levels. Moreover, OMT activated Nrf2 and promoted the nucleus translocation of Nrf2. OMT alleviated the elevated levels of α-SMA, Collagen I, Collagen III, and CTGF, which were abrogated by the Nrf2 siRNA transfection. We also found that OMT decreased oxidative stress levels.

Conclusions

Our results confirm that OMT alleviates transdifferentiation of cardiac fibroblasts to myofibroblasts induced by aldosterone via activating the Nrf2/Keap1 pathway in vitro.

Increased Risk of Autoimmune Disorders in 21-Hydroxylase Deficiency: A Swedish Population-Based National Cohort Study

CONTEXT

The prevalence of autoimmune disorders in individuals with 21-hydroxylase deficiency (21OHD) is unclear. The gene responsible, CYP21A2, is located in a highly immunologically active region.

OBJECTIVE

To study the prevalence of autoimmune disorders in individuals with 21OHD.

DESIGN SETTING AND PARTICIPANTS

Patients with 21OHD (n = 714) were compared with controls matched for sex, year, and place of birth (n = 71,400). Data were derived by linking National Population-Based Registers. Subgroup analyses were performed regarding phenotype and CYP21A2 genotype.

MAIN OUTCOME MEASURES

Number and type of autoimmune disorders.

RESULTS

Mean age (± SD) was 29.8 ± 18.4 years. Individuals with 21OHD had more autoimmune disorders than did controls [7.4% vs 5.1%, P < 0.01; relative risk (RR) 1.47 (95% CI, 1.13 to 1.91)], especially male patients [6.8% vs 4.1%, P < 0.05; RR, 1.64 (95% CI, 1.08 to 2.49)], whereas it did not reach significance for female patients [7.9% vs 5.8%, P = 0.068; RR, 1.37 (95% CI, 0.98 to 1.92)]. Among the specific autoimmune groups and disorders, autoimmune endocrine disorders and autoimmune thyroid disorders, including Graves disease, were significantly increased in the entire cohort of patients and for male and female patients separately. Inflammatory bowel disease (IBD) and systemic connective tissue disorders did not reach significant levels for the entire cohort (P = 0.075 and 0.05, respectively), but male patients were more affected by IBD (P = 0.022). The groups with milder phenotypes and genotypes seemed to be more affected by autoimmune disorders.

CONCLUSIONS

21OHD was associated with an increased prevalence of autoimmune disorders. The relatively young age of the patient cohort and possible protective effects by glucocorticoid treatment may have underestimated the risk.

The Role of Mineralocorticoid Receptor Antagonists in Heart Failure with Reduced Ejection Fraction

Background:

Heart failure (HF) is a worldwide modern epidemic, associated with significant morbidity and mortality. Several causes have been identified for the syndrome, most of which share common pathophysiologic pathways, including neurohormonal activation. Central to the latter lies activation of the reninangiotensin- aldosterone system, and its effects on cardiovascular disease progression.

Objectives:

The aim of this review is to summarize the pathophysiology of aldosterone and the effects of its blockage in the failing heart, as well as to provide state-of-the-art evidence, and address future perspectives regarding the use of mineralocorticoid receptor antagonists in heart failure with reduced ejection fraction.

Method:

Literature was reviewed for studies that assess the pathophysiology of aldosterone in HF with reduced ejection fraction (HFrEF), and the effects of mineralocorticoid receptor antagonists (MRAs) in this condition.

Results:

Several major society guidelines have synthesized the available evidence on HFrEF management, and drugs that block the renin-angiotensin-aldosterone system at different levels continue to form the key component of standard of care for these patients. Mineralocorticoid receptor antagonists are an important part of HFrEF pharmacologic treatment, and their use is supported by a high level of evidence studies. This class of drugs demonstrated significant benefits for morbidity and mortality, across the spectrum oh HFrEF, including patients after acute myocardial infarction.

Conclusion:

Current evidence supports the central role of aldosterone in HFrEF progression, and the significant benefits on outcomes with the use of MRAs.

New roles of aldosterone and mineralocorticoid receptors in cardiovascular disease: translational and sex-specific effects

Recent advances in the field of mineralocorticoid receptor (MR) and its ligand aldosterone expanded the role of this hormone and its receptor far beyond their initial function as a regulator of Na⁺ and K⁺ homeostasis in epithelial cells. The symposium "New Roles of Aldosterone and Mineralocorticoid Receptors in Cardiovascular Disease: Translational and Sex-Specific Effects" presented at the 38th World Congress of the International Union of Physiological Sciences (Rio de Janeiro, Brazil) highlighted the contribution of extrarenal MRs to cardiovascular disease. This symposium showcased how MRs expressed in endothelial, vascular smooth muscle, and immune cells plays a critical role in the development of vascular disease associated with aging, obesity, and chronic aldosterone stimulation and demonstrated that MR antagonism prevents the acute renal dysfunction and tubular injury induced by ischemia-reperfusion injury. It was also shown that the adipocyte-derived hormone leptin is a new direct regulator of aldosterone secretion and that leptin-mediated aldosterone production is a major contributor to obesity-associated hypertension in women. Sex differences in the role of aldosterone and of endothelial MR in the cardiovascular outcomes of obesity were highlighted. This review summarizes these important emerging concepts regarding the contribution of aldosterone and cell-specific MR to cardiovascular disease in male and female subjects and further supports sex-specific benefits of MR antagonist drugs to be tested in additional populations.

Mineralocorticoid receptor antagonism prevents obesity-induced cerebral artery remodeling and reduces white matter injury in rats

OBJECTIVE

Midlife obesity is a risk factor for dementia development. Obesity has also been linked to hyperaldosteronism, and this can be modeled in rats by high fat (HF) feeding from weaning. Aldosterone, or activation of the mineralocorticoid receptor (MR) causes cerebrovascular injury in lean hypertensive rats. We hypothesized that rats fed a HF diet would show inward middle cerebral artery (MCA) remodeling that could be prevented by MR antagonism. We further proposed that the cerebral artery remodeling would be associated with white mater injury.

METHODS

Three-week-old male Sprague-Dawley rats were fed a HF diet ± the MR antagonist canrenoic acid (Canr) for 17 weeks. Control rats received normal chow (control NC). MCA structure was assessed by pressure myography.

RESULTS

The MCAs from HF fed rats had smaller lumens and thicker walls when compared to arteries from control NC rats; Canr prevented the MCA remodeling associated with HF feeding. HF feeding increased the mRNA expression of markers of cell proliferation and vascular inflammation in cerebral arteries and Canr treatment prevented this. White mater injury was increased in the rats fed the HF diet and this was reduced by Canr treatment. The expression of doublecortin, a marker of new and immature neurons was reduced in HF fed rats, and MR antagonism normalized this.

CONCLUSIONS

These data suggest that HF feeding leads to MR dependent remodeling of the MCA and this is associated with markers of dementia development.

Rethinking IL-6 and CRP: Why they are more than inflammatory biomarkers, and why it matters

Behavioral researchers have increasingly become interested in the idea that chronic, low-grade inflammation is a pathway through which social and behavioral variables exert long-term effects on health. Much research in the area employs putative inflammatory biomarkers to infer an underlying state of inflammation. Interleukin 6 (IL-6) and C-reactive protein (CRP, whose production is stimulated by IL-6) are arguably the two most commonly assayed biomarkers. Yet, in contrast with near-universal assumptions in the field, discoveries in immunology over the past two decades show that neither IL-6 nor CRP are unambiguous inflammatory markers. IL-6 operates through two distinct signaling pathways, only one of which is specifically upregulated during inflammation; both pathways have a complex range of effects and influence multiple physiological processes even in absence of inflammation. Similarly, CRP has two isoforms, one of which is produced locally in inflamed or damaged tissues. The other isoform is routinely produced in absence of inflammation and may have net anti-inflammatory effects. We propose a functional framework to account for the multiple actions of IL-6 and CRP. Specifically, we argue that both molecules participate in somatic maintenance efforts; hence elevated levels indicate that an organism is investing in protection, preservation, and/or repair of somatic tissue. Depending on the state of the organism, maintenance may be channeled into resistance against pathogens (including inflammation), pathogen tolerance and harm reduction, or tissue repair. The findings and framework we present have a range of potential implications for the interpretation of empirical findings in this area-a point we illustrate with alternative interpretations of research on socioeconomic status, stress, and depression.

Production of aldosterone in cardiac tissues of healthy dogs and with dilated myocardiopathy

Background and Aim

Aldosterone is a hormone, belonging to the group of mineralocorticoids, mainly synthesized in the adrenal cortex, basically its function is to regulate blood pressure and sodium-potassium levels in the body; high levels of this hormone have harmful effects in the organism and mainly in the heart in chronic form. Dilated cardiomyopathy is a progressive disease of heart muscle that is characterized by ventricular chamber enlargement and contractile dysfunction, is one of the most common cardiac conditions in dogs of medium and large breeds. The aim of the study was to determine and quantify if a dog's cardiac cells possess the capacity to synthesize aldosterone, as well as, the differences that appear between a healthy heart and with dilated myocardiopathy (DMC).

Materials and Methods

Cardiac tissues were used from six healthy dogs and six with DMC. Enzyme-linked immunosorbent assay was performed to determine if the dog's heart cells synthesized this mineralocorticoid in a similar way to rat, rabbit, and human tissues, as well as quantitative differences between the healthy heart and DMC.

Results

In healthy dog hearts, aldosterone values were 62.5 pG for both the atria and right ventricle and 125 pG for the left ventricle. As for dog hearts' with DMC, results were 125 pG in all four cavities.

Conclusion

Both the healthy and DMC dog hearts produce aldosterone in all four cavities, observing that production increases in the atria and right ventricle of those hearts with DMC, as an intrinsic mechanism of cardiac remodeling.

Modulation of transcriptional mineralocorticoid receptor activity by casein kinase 2

The pathogenesis of cardiovascular diseases is a multifunctional process in which the mineralocorticoid receptor (MR), a ligand-dependent transcription factor, is involved as proven by numerous clinical studies. The development of pathophysiological MR actions depends on the existence of additional factors e.g. inflammatory cytokines and seems to involve posttranslational MR modifications e.g. phosphorylation. Casein kinase 2 (CK2) is a ubiquitously expressed multifunctional serine/threonine kinase that can be activated under inflammatory conditions as the MR. Sequence analysis and inhibitor experiments revealed that CK2 acts as a positive modulator of MR activity by facilitating MR-DNA interaction with subsequent rapid MR degradation. Peptide microarrays and site-directed mutagenesis experiments identified the highly conserved S459 as a functionally relevant CK2 phosphorylation site of the MR. Moreover, MR-CK2 protein-protein interaction mediated by HSP90 was shown by co-immunoprecipitation. During inflammation, cytokine stimulation led to a CK2-dependent increased expression of proinflammatory genes. The additional MR activation by aldosterone during cytokine stimulation augmented CK2-dependent NFκB signaling which enhanced the expression of proinflammatory genes further. Overall, in an inflammatory environment the bidirectional CK2-MR interaction aggravate the existing pathophysiological cellular situation.

Controversies in Veterinary Nephrology: Renal Diets Are Indicated for Cats with International Renal Interest Society Chronic Kidney Disease Stages 2 to 4: The Con View

Renal diets typically incorporate protein and phosphorus restriction, supplement with potassium and Omega-3 fatty acids, and address metabolic acidosis. Compared to "maintenance" diets, these modifications appear to benefit cats with chronic kidney disease (CKD). However, there is limited data in cats justifying the specific amounts of the nutrients used in these diets, and there is little evidence supporting protein restriction in cats with CKD. Energy intake, maintenance of body weight, and muscle and body condition need to be addressed, and may take precedence over special diets. Further research is needed to better define optimum diets for cats with CKD.