Sexual Dimorphism in Obesity-Associated Endothelial ENaC Activity and Stiffening in Mice.

Obesity and insulin resistance stiffen the vasculature, with females appearing to be more adversely affected. As augmented arterial stiffness is an independent predictor of cardiovascular disease (CVD), the increased predisposition of women with obesity and insulin resistance to arterial stiffening may explain their heightened risk for CVD. However, the cellular mechanisms by which females are more vulnerable to arterial stiffening associated with obesity and insulin resistance remain largely unknown. In this study, we provide evidence that female mice are more susceptible to Western diet-induced endothelial cell stiffening compared with age-matched males. Mechanistically, we show that the increased stiffening of the vascular intima in Western diet-fed female mice is accompanied by enhanced epithelial sodium channel (ENaC) activity in endothelial cells (EnNaC). Our data further indicate that: (i) estrogen signaling through estrogen receptor α (ERα) increases EnNaC activity to a larger extent in females compared with males, (ii) estrogen-induced activation of EnNaC is mediated by the serum/glucocorticoid inducible kinase 1 (SGK-1), and (iii) estrogen signaling stiffens endothelial cells when nitric oxide is lacking and this stiffening effect can be reduced with amiloride, an ENaC inhibitor. In aggregate, we demonstrate a sexual dimorphism in obesity-associated endothelial stiffening, whereby females are more vulnerable than males. In females, endothelial stiffening with obesity may be attributed to estrogen signaling through the ERα-SGK-1-EnNaC axis, thus establishing a putative therapeutic target for female obesity-related vascular stiffening.

Role of aldosterone and angiotensin II in insulin resistance: an update.

The role of the Renin-Angiotensin-Aldosterone system (RAAS) on the development of insulin resistance and cardiovascular disease is an area of growing interest. Most of the deleterious actions of the RAAS on insulin sensitivity appear to be mediated through activation of the Angiotensin II (Ang II) Receptor type 1 (AT(1)R) and increased production of mineralocorticoids. The underlying mechanisms leading to impaired insulin sensitivity remain to be fully elucidated, but involve increased production of reactive oxygen species and oxidative stress. Both experimental and clinical studies also implicate aldosterone in the development of insulin resistance, hypertension, endothelial dysfunction, cardiovascular tissue fibrosis, remodelling, inflammation and oxidative stress. There is abundant evidence linking aldosterone, through non-genomic actions, to defective intracellular insulin signalling, impaired glucose homeostasis and systemic insulin resistance not only in skeletal muscle and liver but also in cardiovascular tissue. Blockade of the different components of the RAAS, in particular Ang II and AT(1)R, results in attenuation of insulin resistance, glucose homeostasis, as well as decreased cardiovascular disease morbidity and mortality. These beneficial effects go beyond to those expected with isolated control of hypertension. This review focuses on the role of Ang II and aldosterone in the pathogenesis of insulin resistance, as well as in clinical relevance of RAAS blockade in the prevention and treatment of the metabolic syndrome and cardiovascular disease.

The role of aldosterone in cardiovascular disease in people with diabetes and hypertension: an update.

The role of mineralocorticoids in the development of cardiovascular disease (CVD), cardiometabolic syndrome, type 2 diabetes mellitus, chronic kidney disease (CKD), and hypertension is a growing field of interest. Aldosterone, mainly through nongenomic actions that result in proliferation, fibrosis, inflammation, and tissue remodeling, has been linked to CVD and CKD. Increased circulating aldosterone is also associated with insulin resistance and impaired glucose homeostasis that contribute to the development of endothelial dysfunction, atherosclerosis, and kidney disease. Aldosterone-induced oxidative stress and inflammation play a key role in impairing insulin signaling. Mineralocorticoid receptor blockade restores insulin sensitivity, counterbalances the deleterious cardiovascular and renal effects of aldosterone, and emerges as an alternative to improve blockade of the renin-angiotensin-aldosterone system, which potentially could contribute to reduce the burden of CVD and CKD.

The endocannabinoid network: insight into the regulation of the neuroendocrine and metabolic systems.

The dramatic increase in the prevalence of obesity worldwide represents one of the most important challenges of modern medicine, owing to its myriad related complications-in particular cardiovascular disease, the leading cause of death worldwide. Originating from early studies with Cannabis sativa, the active compound of marijuana, there has been an impressive progress in the knowledge about the endocannabinoid network, leading to the identification of specific pathways that modulate feeding behavior. The effects of endocannabinoids are not limited to the central nervous system, but also include peripheral tissues. Experimental and clinic trials have demonstrated the efficacy of endocannabinoid antagonists in the management of obesity and the cardiometabolic syndrome. Better understanding of the mechanisms underlying obesity will lead to development of more active and specific agents, which surely will enlarge the role of this efficacious alternative for management of obesity.

Insights into the emerging cardiometabolic prevention and management of diabetes mellitus.

Cardiovascular disease (CVD) and Type 2 diabetes mellitus (DM2), once conceived as different entities, share common origins and pathways. Increased activity of the renin-angiotensin-aldosterone-system, insulin resistance, chronic low-grade inflammation and oxidative stress collectively contribute to endothelial dysfunction and atherosclerosis, which manifest clinically as CVD. Nowadays, it is possible to identify and intervene in high-risk populations even before the clinical diagnosis of DM2. The control of dietary patterns and increased physical activity is completely feasible, as well as the management of hypertension and dyslipidaemia. Pharmacological interventions targeted at blocking renin-angiotensin-aldosterone-system and sensitising to insulin have a role in the prevention of DM2 and CVD, and are avidly explored worldwide. In the near future, ongoing trials should provide data that will allow us to better treat patients with the cardiometabolic syndrome and diabetes in order to reduce CVD morbidity and mortality.