Angiotensin-converting enzymes as druggable features of psychiatric and neurodegenerative disorders.

The renin-angiotensin system (RAS) plays essential roles in maintaining peripheral cardiovascular homeostasis, with its potential roles in the brain only being recognized more recently. Angiotensin-I-converting enzyme (ACE) is the main component of the RAS, and it has been implicated in various disorders of the brain. ACE and other RAS components, including the related enzyme ACE2, angiotensin peptides and their respective receptors, can participate in the pathological state, as well as with potential to contribute to neuroprotection and/or to complement existing treatments for psychiatric illness. In this narrative review, we aimed to identify the main studies describing the functions of the RAS and ACEs in the brain and their association with brain disorders. These include neurodegenerative disorders such as Parkinson's and Alzheimer's diseases, psychiatric illnesses such as schizophrenia, bipolar disorder, and depression. We also discuss the possible association of a functional polymorphism of the ACE gene with these brain diseases and the relevance of the neuroprotective and anti-inflammatory properties of ACE inhibitors (ACEis) and angiotensin receptor blockers (ARBs). Based on this, we conclude that there is significant potential value to the inclusion of ACEis and/or ARBs as a novel integrated approach for the treatment of various disorders of the brain, and particularly for psychiatric illness.

Angiotensin Receptor Blockers for COVID-19: Pathophysiological and Pharmacological Considerations About Ongoing and Future Prospective Clinical Trials.

COVID-19 pandemic demands a swift response to find therapeutic tools that effectively reduce morbidity and mortality. Despite initial fears, evidence from retrospective observational studies supports the inhibition of the renin-angiotensin system as an emerging pathway to delay or moderate angiotensin II-driven lung inflammation. This has triggered several prospective clinical trials. In this commentary we provide an overview and analysis of current ongoing clinical trials aimed at evaluating the therapeutic efficacy of angiotensin receptor blocker (ARB) use in COVID-19. The relevance of the results of these trials will have to be interpreted depending on the stage and severity of the disease and in light of the start time of their prescription related to the time of diagnosis of COVID-19 as well as the administered doses.

[The RAAS and SARS-CoV-2: A riddle to solve]. / El SRAA y el SARS-CoV-2: el acertijo a resolver.

The first case of COVID-19 was reported on 31 December 2019 in Wuhan, China. Ever since there has been unprecedented and growing interest in learning about all aspects of this new disease. Debate has been generated as to the association between antihypertensive therapy with renin-angiotensin-aldosterone system (RAAS) inhibitors and SARS-CoV-2 infection. While many questions as yet remain unanswered, the aim of this report is to inform health professionals about the current state of knowledge. Because this is an ever-evolving topic, the recommendation is that it be updated as new evidence becomes available. Below, we provide a review of pre-clinical and clinical studies that link coronavirus to the RAAS.

Is Chronic Kidney Disease Progression Influenced by the Type of Renin-Angiotensin-System Blocker Used?

INTRODUCTION: Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) reduce proteinuria and slow renal disease progression more effectively than other therapies in patients with chronic kidney disease (CKD). However, differences regarding efficacy and safety between these therapies remain controversial. OBJECTIVES: Aim of this study was to analyze the different treatment effect of ACEI, ARB, and non-ACEI/ARB in CKD progression. The primary outcome was survival to end-stage renal disease (ESRD) and/or death and to ESRD censored by all-cause death, secondary outcomes were proteinuria reduction and hyperkalemia. METHODS: We analyzed data from 1,120 patients extracted from the National Renal Healthcare Program cohort, which included 17,238 CKD nondialysis subjects who were successively monitored between -September 1, 2004 and August 31, 2016. Inclusion criteria were at least a 1-year follow-up, 3 clinical visits, and no previous treatment with ACEI or ARB. From the baseline visit onward, patients continued with 3 different treatment schemes: no ACEI/ARB, started on ACEI or ARB, but while avoiding both treatments in combination. Chi2, t test, binary logistic regression, and multivariate regression models (Cox proportional Hazard model and competing risk Fine and Gray model were used for statistical analysis. RESULTS: Mean age and follow-up were 67.9 (± 15) and 3.8 (± 2) years, respectively. Estimated glomerular filtration rate averaged 42.1 ± 23 mL/min/1.73 m2 and 300 (27%) patients were diabetics. Progression to ESRD was significantly worse in the no ACEI/ARB group (hazard ratio [HR] 4.23, 95% CI 1.28-13.92) versus ACEI (reference group; p = 0.01). The analysis by competing-risks' regression showed significantly higher risk of ESRD in the no ACEI/ARB group (HR 3.63, 95% CI 1.34-9.85) versus ACEI (p = 0.01). There were no significant differences between ACEI and ARB groups (HR 1.31, 95% CI 0.37-4.66) regarding the risk of progression to ESRD. Survival was similar in all 3 groups (p = 0.051). Statistically significantly more patients experienced reductions in proteinuria/albuminuria in ACEI and ARB groups (together) versus no ACEI/ARB group (p = 0.016, OR 1.82, 95% CI 1.12-2.94). No difference in hyperkalemia frequency was found between them (p = 0.17). CONCLUSIONS: In patients with CKD, treatment with ACEI or ARB had a superior effect than no ACEI or ARB treatment on slowing kidney disease progression and on proteinuria reduction. Efficacy of ACEI and ARB was comparable.

The effects of chronic candesartan treatment on cardiac and hepatic adenosine monophosphate-activated protein kinase in rats submitted to surgical stress.

INTRODUCTION: adenosine monophosphate-activated protein kinase (AMPK) plays a prominent role as a metabolic stress sensor, and it has recently been suggested that the renin-angiotensin system, in addition to its role in stress regulation, may play a significant role in regulating the AMPK system. This study aimed to evaluate the effects of candesartan, an angiotensin II receptor blocker, on cardiac and hepatic AMPK activity basally as well as after surgical stress under general anesthesia. MATERIALS AND METHODS: Male Wistar rats were treated with 5 mg/kg/day candesartan in their drinking water for two weeks. Levels of cardiac and hepatic AMPK activity were determined, using a kinase activity assay, basally and after surgical stress under general anesthesia. RESULTS: Chronic administration of candesartan increased hepatic AMPK activity approximately 4 times (p<0.05) while no significant change was demonstrated in cardiac AMPK. Cardiac and hepatic AMPK activities were not significantly increased by surgical stress alone performed under anesthesia. However, chronic treatment with candesartan decreased AMPK activity in both liver and heart after surgical stress under anesthesia (p<0.01 for both comparisons). CONCLUSIONS: While chronic candesartan treatment may stimulate AMPK activity in certain organs such as the liver, when combined with surgical stress under anesthesia it inhibits pathways regulating AMPK activity.

The world pandemic of vitamin D deficiency could possibly be explained by cellular inflammatory response activity induced by the renin-angiotensin system.

This review attempts to show that there may be a relationship between inflammatory processes induced by chronic overstimulation of the renin-angiotensin system (RAS) and the worldwide deficiency of vitamin D (VitD) and that both disorders are probably associated with environmental factors. Low VitD levels represent a risk factor for several apparently different diseases, such as infectious, autoimmune, neurodegenerative, and cardiovascular diseases, as well as diabetes, osteoporosis, and cancer. Moreover, VitD insufficiency seems to predispose to hypertension, metabolic syndrome, left ventricular hypertrophy, heart failure, and chronic vascular inflammation. On the other hand, inappropriate stimulation of the RAS has also been associated with the pathogenesis of hypertension, heart attack, stroke, and hypertrophy of the left ventricle and vascular smooth muscle cells. Because VitD receptors (VDRs) and RAS receptors are almost distributed in the same tissues, a possible link between VitD and the RAS is even more plausible. Furthermore, from an evolutionary point of view, both systems were developed simultaneously, actively participating in the regulation of inflammatory and immunological mechanisms. Changes in RAS activity and activation of the VDR seem to be inversely related; thus any changes in one of these systems would have a completely opposite effect on the other, making it possible to speculate that the two systems could have a feedback relationship. In fact, the pandemic of VitD deficiency could be the other face of increased RAS activity, which probably causes lower activity or lower levels of VitD. Finally, from a therapeutic point of view, the combination of RAS blockade and VDR stimulation appears to be more effective than either RAS blockade or VDR stimulation individually.