The serum angiotensin-converting enzyme 2 and angiotensin-(1-7) concentrations after optimal therapy for acute decompensated heart failure with reduced ejection fraction

Renin-angiotensin system inhibitors positively impact on multiple aging regulatory pathways: Could they be used to protect against human aging?

The renin-angiotensin system (RAS)-a classical blood pressure regulator-largely contributes to healthy organ development and function. Besides, RAS activation promotes age-related changes and age-associated diseases, which are attenuated/abolished by RAS-blockade in several mammalian species. RAS-blockers also increase rodent lifespan. In previous work, we discussed how RAS-blockade downregulates mTOR and growth hormone/IGF-1 signaling, and stimulates AMPK activity (together with klotho, sirtuin, and vitamin D-receptor upregulation), and proposed that at least some of RAS-blockade's aging benefits are mediated through regulation of these intermediaries and their signaling to mitochondria. Here, we included RAS-blockade's impact on other aging regulatory pathways, that is, TGF-ß, NF-kB, PI3K, MAPK, PKC, Notch, and Wnt, all of which affect mitochondria. No direct evidence is available on RAS/RAS-blockade-aging regulatory pathway-mitochondria interactions. However, existing results allow to conjecture that RAS-blockers neutralize mitochondrial dysfunction by acting on the discussed pathways. The reviewed evidence led us to propose that the foundation is laid for conducting clinical trials aimed at testing whether angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB)-even at subclinical doses-offer the possibility to live longer and in better health. As ACEi and ARB are low cost and well-tolerated anti-hypertension therapies in use for over 35 years, investigating their administration to attenuate/prevent aging effects seems simple to implement.

Decrease in Angiotensin-Converting Enzyme activity but not concentration in plasma/lungs in COVID-19 patients offers clues for diagnosis/treatment

Although several therapeutics are used to treat coronavirus disease 2019 (COVID-19) patients, there is still no definitive metabolic marker to evaluate disease severity and recovery or a quantitative test to end quarantine. Because severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infects human cells via the angiotensin-converting-enzyme 2 (ACE2) receptor and COVID-19 is associated with renin-angiotensin system dysregulation, we evaluated soluble ACE2 (sACE2) activity in the plasma/saliva of 80 hospitalized COVID-19 patients and 27 non-COVID-19 volunteers, and levels of ACE2/Ang (1-7) in plasma or membrane (mACE2) in lung autopsy samples. sACE2 activity was markedly reduced (p < 0.0001) in COVID-19 plasma (n = 59) compared with controls (n = 27). Nadir sACE2 activity in early hospitalization was restored during disease recovery, irrespective of patient age, demographic variations, or comorbidity; in convalescent plasma-administered patients (n = 45), restoration was statistically higher than matched controls (n = 22, p = 0.0021). ACE2 activity was also substantially reduced in the saliva of COVID-19 patients compared with controls (p = 0.0065). There is a strong inverse correlation between sACE2 concentration and sACE2 activity and Ang (1-7) levels in participant plasmas. However, there were no difference in membrane ACE2 levels in lungs of autopsy tissues of COVID-19 (n = 800) versus other conditions (n = 300). These clinical observations suggest sACE2 activity as a potential biomarker and therapeutic target for COVID-19.

Association Between the Angiotensin II/Angiotensin (1-7) Imbalance and Left Ventricular Hypertrophy in Patients with Heart Failure

Introduction: Angiotensin II (AngII) and angiotensin-(1-7) [Ang-(1-7)] are key components of the renin angiotensin system (RAS). They exhibit counter-regulatory effects in the systemic circulation, as well as in tissues important for cardiovascular regulation.

Aim: To investigate the association between the AngII/Ang-(1-7) balance and left ventricular hypertrophy (LVH) in patients with heart failure and mid-range ejection fraction (HFmrEF).

Material and methods: 56 patients with HFmrEF were included, with a mean age of 65.62 ± 9.69 years and 22 age- and sex-matched healthy subjects, their mean age - 56.4 ± 5.53 years. The patients were divided in two subgroups: subjects with left ventricular hypertrophy (n = 32); (HFmrEF+LVH) and subjects without left ventricular hypertrophy (n = 24); (HFmrEFLVH). AngII and Ang-(1-7) levels were measured with an ELISA kit.

Results: Patients with HFmrEF+LVH showed significantly higher levels of AngII: 8.53 pg/mL (1.47 ÷ 13.0) than HFmrEF-LVH – 1.33 pg/mL (0.47 ÷ 6.93) and healthy controls – 1.53 pg/mL (0.27 ÷ 5.21); (KW = 3.48; p = 0.04). There was no significant difference between Ang-(1-7) levels in all patients compared to controls (p > 0.05). AngII/Ang-(1-7) ratio was significantly higher in all patients than controls: 3.81 (2.03 ÷ 6.66) vs. 1.5 (0.93 ÷ 2.06) (KW = 18.68; p < 0.001). Patients with HFmrEF+LVH showed statistically higher AngII/Ang-(1-7) ratio compared with controls (4.7 vs. 1.5). Moreover, subjects with LVH showed the highest AngII/Ang-(1-7) ratio among all particpants in the study. The AngII/Ang-(1-7) ratio correlated with LVH (r = -0.39; p = 0.03), DBP (r = 0.25; p = 0.04), HDL (r = 0.33; p = 0.01), SBP (r = 0.34; p = 0.01).

Conclusion: Our study showed an association between AngII/Ang-(1-7) ratio, blood pressure and LVH. The imbalance between Ang-II and Ang-(1-7) could contribute to the mechanisms determining LVH in HFmrEF. Further studies are warranted to clarify whether evaluation of serum Ang-II/Ang-(1-7) ratio could predict LVH development in patients with HFmrEF.