Stimulation of aldosterone synthesis by angiotensin II in the brain: support for positive feedback in hypertension?

Mineralocorticoid Dysfunction during Critical Illness: A Review of the Evidence

The recent demonstration of the significant reduction in mortality in patients with septic shock treated with adjunctive glucocorticoids combined with fludrocortisone and the effectiveness of angiotensin II in treating vasodilatory shock have renewed interest in the role of the mineralocorticoid axis in critical illness. Glucocorticoids have variable interactions at the mineralocorticoid receptor. Similarly, mineralocorticoid receptor-aldosterone interactions differ from mineralocorticoid receptor-glucocorticoid interactions and predicate receptor-ligand interactions that differ with respect to cellular effects. Hyperreninemic hypoaldosteronism or selective hypoaldosteronism, an impaired adrenal response to increasing renin levels, occurs in a subgroup of hemodynamically unstable critically ill patients. The suggestion is that there is a defect at the level of the adrenal zona glomerulosa associated with a high mortality rate that may represent an adaptive response aimed at increasing cortisol levels. Furthermore, cross-talk exists between angiotensin II and aldosterone, which needs to be considered when employing therapeutic strategies.

An update on the advancements in the treatment of agitation in Alzheimer's disease

INTRODUCTION

Neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD) are associated with significant negative outcomes for patients and their caregivers. Agitation, one of the most distressing NPS, lacks safe and effective long term interventions. Nonpharmacological interventions are suggested as first-line treatment, but aren't effective for every patient, resulting in pharmacological interventions for some patients, consisting of off-label use of antipsychotics, sedative/hypnotics, anxiolytics, acetylcholinesterase inhibitors, memantine, and antidepressants; where efficacy doesn't necessarily outweigh associated risks. Areas covered: Gains in understanding neurobiological mechanisms underlying agitation have fueled several recent clinical trials. This article updates our review published in 2014. Comprehensive literature search for published articles from January 2014 to December 2016 evaluating pharmacologic interventions for agitation in AD was done. A review of several clinical trials was completed: dextromethorphan/quinidine, scyllo-inositol, brexpiprazole, prazosin, cannabinoids, citalopram, escitalopram, pimavanserin, ITI-007, ORM-12741 show promise in treating agitation. Expert opinion: Neurobiological findings, innovative trials designs, statistical approaches, and preliminary paths for regulatory agency acceptance have re-ignited the area of pharmacological treatment of NPS. Though further research is needed to fully determine the safety, tolerability and efficacy of these treatments, the mission to find effective treatments for neuropsychiatric symptoms such as agitation in patients with dementia is well underway.

Aldosterone, cognitive function, and cerebral hemodynamics in hypertension and antihypertensive therapy

BACKGROUND

Animal studies suggest that the renin-angiotensin-aldosterone system is involved in neurocognitive function and the response to antihypertensive therapy. We investigated the impact of circulating aldosterone and renin activity on cognition and cerebral hemodynamics at baseline and after antihypertensive therapy for 1 year.

METHODS

Participants were older adults (n = 47; mean age = 71 years) enrolled in a clinical trial. Routine antihypertensive medications were replaced with the study regimen to achieve a blood pressure <140/90 mm Hg. Executive function, memory, cerebral hemodynamics (blood flow velocity), CO2 vasoreactivity (measured using transcranial Doppler ultrasonography), plasma renin activity, and aldosterone were measured at baseline and at 6 and 12 months after the initiation of treatment.

RESULTS

At baseline, higher levels of circulating aldosterone were associated with lower blood flow velocity (β = -0.02; P = 0.03), lower CO2 vasoreactivity (β = -0.11; P = 0.007), and decreased autoregulation abilities (β = -0.09; P = 0.01). Those with higher levels of aldosterone at baseline demonstrated the greatest improvement in executive function (P = 0.014 for the aldosterone effect) and in CO2 vasoreactivity (P = 0.026 for the aldosterone effect) after 12 months of lowering blood pressure (<140/90 mm Hg). Plasma renin activity was not associated with any of the measures.

CONCLUSIONS

Higher levels of aldosterone may be associated with decreased cerebrovascular function in hypertension. Those with higher aldosterone levels may benefit the most from lowering blood pressure. The role of aldosterone in brain health warrants further investigation in a larger trial.