Renin Aldosterone Angiotensin System Research Articles

Aldosterone synergizes with peripheral inflammation to induce brain IL-1β expression and depressive-like effects

Recent findings have shown that the physiological functions of the hormone aldosterone go far beyond its well-known role in blood-pressure regulation and salt/water homeostasis. Aldosterone is for example involved in the regulation of inflammation, and also binds directly to mineralocorticoid receptors in specific brain regions. Interestingly, depressive symptoms appear to correlate with alterations of the aldosterone system but the underlying mechanisms have not been elucidated.In this study aldosterone (2μg/100g body weight/day) was continuously administered via osmotic minipumps for 5days. Lipopolysaccharide (LPS) was administered once a day for 5days in a dose of 1mg/kg ip. The rats were tested for depressive-like behavior 24h after the last LPS injection. Protein levels of cytokines were measured in serum and cerebrospinal fluid (CSF). mRNA expression of interleukin (IL)-1β and IL-6 in the prefrontal cortex (PFC) was analyzed using reverse transcriptase qPCR.We found that aldosterone treatment increased LPS-induced IL-1β mRNA expression in the PFC and CSF. Moreover, there was a positive correlation between IL-1β in CSF and depressive-like behaviors. These findings suggest that IL-1β is affected by the renin–aldosterone–angiotensin system (RAAS) activity and connected to symptoms of depression.

Target Organ Damage in Hypertension: Pathophysiology and Implications for Drug Therapy

Hypertension is a well known risk factor for cardiovascular and cerebrovascular events such as heart attacks and strokes. In addition, it is associated with earlier changes in organ systems in the body, such as left ventricular hypertrophy (LVH), proteinuria and renal failure, retinopathy and vascular dementia which are grouped under the term "target organ damage" (TOD). There are many processes involved in the pathogenesis of TOD and these include endothelial activation, platelet activation, increased thrombogenesis, changes in the renin aldosterone angiotensin system (RAAS), and collagen turnover. All these changes work hand in hand and lead to the production of hypertensive TOD. In this review, we aim to provide an overview of the recent advances in pathophysiology of hypertensive TOD, and examine how these changes lead to the production of TOD. A better understanding of these pathogenic processes would help us better devise treatment strategies in preventing the dreaded complications associated with hypertension.

International Society for Heart and Lung Transplantation: Practice guidelines for management of heart failure in children

Heart failure (HF) in the United States is well recognized as a major public health problem, with over 900,000 hospital admissions annually in the United States, and greater than 250,000 deaths per year. The great majority of heart failure occurs in adults. In children, the scope of the problem is less well defined, but recent data from the Pediatric Cardiomyopathy Registry suggest an annual incidence of 1.13 cases of cardiomyopathy per 100,000 children. 1 While some of this represents asymptomatic disease, the burden of disease overall is nonetheless quite high. In the Pediatric Cardiomyopathy Registry, the majority of children with cardiomyopathy also had HF, with mortality rates of 13.6% at 2 years in dilated forms of cardiomyopathy. The etiology of heart failure differs greatly between children and adults. Children in the Pediatric Cardiomyopathy Registry had a recognizable syndrome or genetic diagnosis in 27% of cases, with an additional 5% of cases due to myocarditis. Furthermore, a large percentage of children with end-stage HF (between 25% and 75%, depending upon the age group) have an underlying diagnosis of congenital heart disease. 2 In contrast to adult patients, ischemic heart disease is rare in children. There is a large, and rapidly growing literature addressing HF treatment for adult patients, with a much smaller literature concerning HF therapy in children. Excellent guidelines for adult patients have recently been published, but given the significant differences between adult and pediatric patients with HF, there is little reason to believe that these guidelines are directly applicable to children. 3 Accordingly, in this document we have attempted to summarize the relevant literature and synthesize management guidelines for children with HF. The document that follows has been prepared in a consensus fashion, with input from pediatric cardiologists at multiple sites throughout the United States and Canada.

Peritoneovenous shunting restores atrial natriuretic factor responsiveness in refractory hepatic ascites

Background: Sodium retention in cirrhosis has been attributed to an imbalance between vasoconstrictive, antinatriuretic forces such as the renin aldosterone angiotensin system and the sympathetic nervous system, and vasodilatory, natriuretic agents such as atrial natriuretic factor (ANF). Patients with diuretic resistant refractory ascites may require peritoneovenous shunting (PVS) to control ascites. Methods: To study the factors responsible for the improvement in sodium homeostasis post-PVS, we compared the response to ANF infusion before and 1 month after PVS in 6 patients with massive ascites. Results: Before PVS, sodium excretion at baseline and in response to ANF infusion was blunted but became more normal post-PVS. ANF infusion post-PVS induced a significant increase in the glomerular filtration rate and filtration fraction and also in distal delivery of sodium. ANF's distal effect of increasing the fractional excretion of distally delivered sodium was present pre-PVS and was not significantly increased post-PVS. Changes in sodium handling were accompanied by a significant decrease in antinatriuretic forces (baseline aldosterone, 2079 ± 507 vs. 647 ± 17 nmol/L; P < 0.04) post-PVS. Conclusions: The improvement in sodium homeostasis and response to ANF infusion post-PVS appears to be associated with the decrease in antinatriuretic forces with the loss of massive refractory ascites. Thus, PVS restores the balance toward ANF responsiveness.