Targeting and Modulation of the Natriuretic Peptide System in Covid-19: A Single or Double-Edged Effect?

Natriuretic peptide system (NPS) is a group of peptide hormones or paracrine factors, including atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and natriuretic peptide precursor C (NPC), that are structurally related. The physiological effects of NPS include natriuresis, increased glomerular filtration rate, inhibition release of renin, vasopressin, and aldosterone, sympathetic inhibition, vasodilatations, and prevents cardiac hypertrophy and remodeling. ANP has immunological effects, as it is produced locally from immune cells; it regulates innate and adaptive immune responses. Metabolism and degradation of ANP are achieved by neutral endopeptidase (NEP), also known as neprilysin. Coronavirus disease 2019 (Covid-19) pandemic may lead to acute lung injury (ALI) and/or respiratory distress syndrome (ARDS). The underlying causes of inflammatory and immunological disorders in patients with severe Covid-19 are connected to the immune over-stimulation with the subsequent release of pro-inflammatory cytokines. Covid-19 severity is linked with high ANP serum levels regardless of acute cardiac injury. Inflammatory stimuli appear to be linked with the release of NPs, which anti-inflammatory effects prevent the development of ALI/ARDS in Covid-19. Therefore, neprilysin inhibitors like sacubitril increase endogenous NPs and may reduce the risk of ALI in Covid-19 due to the potentiation of endogenous anti-inflammatory effects of NPs. However, sacubitril increases gastrin-releasing peptide, cathepsin G and release of pro-inflammatory cytokines that are inactivated by neprilysin. In conclusion, NPs and neprilysin have cardio-pulmonary protective effects against Covid-19-induced ALI/ARDS. Neprilysin inhibitor sacubitril has dual protective and harmful effects regarding metabolizing vasoactive peptides by neprilysin. These findings require potential reevaluation of the effect of neprilysin inhibitors in managing Covid-19.

Angiotensin Receptor-Neprilysin Inhibition in Acute Myocardial Infarction.

BACKGROUND: In patients with symptomatic heart failure, sacubitril-valsartan has been found to reduce the risk of hospitalization and death from cardiovascular causes more effectively than an angiotensin-converting-enzyme inhibitor. Trials comparing the effects of these drugs in patients with acute myocardial infarction have been lacking. METHODS: We randomly assigned patients with myocardial infarction complicated by a reduced left ventricular ejection fraction, pulmonary congestion, or both to receive either sacubitril-valsartan (97 mg of sacubitril and 103 mg of valsartan twice daily) or ramipril (5 mg twice daily) in addition to recommended therapy. The primary outcome was death from cardiovascular causes or incident heart failure (outpatient symptomatic heart failure or heart failure leading to hospitalization), whichever occurred first. RESULTS: A total of 5661 patients underwent randomization; 2830 were assigned to receive sacubitril-valsartan and 2831 to receive ramipril. Over a median of 22 months, a primary-outcome event occurred in 338 patients (11.9%) in the sacubitril-valsartan group and in 373 patients (13.2%) in the ramipril group (hazard ratio, 0.90; 95% confidence interval [CI], 0.78 to 1.04; P = 0.17). Death from cardiovascular causes or hospitalization for heart failure occurred in 308 patients (10.9%) in the sacubitril-valsartan group and in 335 patients (11.8%) in the ramipril group (hazard ratio, 0.91; 95% CI, 0.78 to 1.07); death from cardiovascular causes in 168 (5.9%) and 191 (6.7%), respectively (hazard ratio, 0.87; 95% CI, 0.71 to 1.08); and death from any cause in 213 (7.5%) and 242 (8.5%), respectively (hazard ratio, 0.88; 95% CI, 0.73 to 1.05). Treatment was discontinued because of an adverse event in 357 patients (12.6%) in the sacubitril-valsartan group and 379 patients (13.4%) in the ramipril group. CONCLUSIONS: Sacubitril-valsartan was not associated with a significantly lower incidence of death from cardiovascular causes or incident heart failure than ramipril among patients with acute myocardial infarction. (Funded by Novartis; PARADISE-MI ClinicalTrials.gov number, NCT02924727.).

Effect of Treatment With Sacubitril/Valsartan in Patients With Advanced Heart Failure and Reduced Ejection Fraction: A Randomized Clinical Trial.

Importance: The use of sacubitril/valsartan is not endorsed by practice guidelines for use in patients with New York Heart Association class IV heart failure with a reduced ejection fraction because of limited clinical experience in this population. Objective: To compare treatment with sacubitril/valsartan treatment with valsartan in patients with advanced heart failure and a reduced ejection fraction and recent New York Heart Association class IV symptoms. Design, Setting, and Participants: A double-blind randomized clinical trial was conducted; a total of 335 patients with advanced heart failure were included. The trial began on March 2, 2017, and was stopped early on March 23, 2020, owing to COVID-19 risk. Intervention: Patients were randomized to receive sacubitril/valsartan (target dose, 200 mg twice daily) or valsartan (target dose, 160 mg twice daily) in addition to recommended therapy. Main Outcomes and Measures: The area under the curve (AUC) for the ratio of N-terminal pro-brain natriuretic peptide (NT-proBNP) compared with baseline measured through 24 weeks of therapy. Results: Of the 335 patients included in the analysis, 245 were men (73%); mean (SD) age was 59.4 (13.5) years. Seventy-two eligible patients (18%) were not able to tolerate sacubitril/valsartan, 100 mg/d, during the short run-in period, and 49 patients (29%) discontinued sacubitril/valsartan during the 24 weeks of the trial. The median NT-proBNP AUC for the valsartan treatment arm (n = 168) was 1.19 (IQR, 0.91-1.64), whereas the AUC for the sacubitril/valsartan treatment arm (n = 167) was 1.08 (IQR, 0.75-1.60). The estimated ratio of change in the NT-proBNP AUC was 0.95 (95% CI 0.84-1.08; P = .45). Compared with valsartan, treatment with sacubitril/valsartan did not improve the clinical composite of number of days alive, out of hospital, and free from heart failure events. Aside from a statistically significant increase in non-life-threatening hyperkalemia in the sacubitril/valsartan arm (28 [17%] vs 15 [9%]; P = .04), there were no observed safety concerns. Conclusions and Relevance: The findings of this trial showed that, in patients with chronic advanced heart failure with a reduced ejection fraction, there was no statistically significant difference between sacubitril/valsartan and valsartan with respect to reducing NT-proBNP levels. Trial Registration: ClinicalTrials.gov Identifier: NCT02816736.

The Rationale for Angiotensin Receptor Neprilysin Inhibitors in a Multi-Targeted Therapeutic Approach to COVID-19.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) determines the angiotensin converting enzyme 2 (ACE2) down-regulation and related decrease in angiotensin II degradation. Both these events trigger "cytokine storm" leading to acute lung and cardiovascular injury. A selective therapy for COVID-19 has not yet been identified. Clinical trials with remdesivir gave discordant results. Thus, healthcare systems have focused on "multi-targeted" therapeutic strategies aiming at relieving systemic inflammation and thrombotic complications. No randomized clinical trial has demonstrated the efficacy of renin angiotensin system antagonists in reducing inflammation related to COVID-19. Dexamethasone and tocilizumab showed encouraging data, but their use needs to be further validated. The still-controversial efficacy of these treatments highlighted the importance of organ injury prevention in COVID-19. Neprilysin (NEP) might be an interesting target for this purpose. NEP expression is increased by cytokines on lung fibroblasts surface. NEP activity is elevated in acute respiratory distress syndrome and it is conceivable that it is also high in COVID-19. NEP is implicated in the degradation of natriuretic peptides, bradykinin, substance P, adrenomedullin, and apelin that account for prevention of organ injury. Thus, NEP/angiotensin receptor type 1 (AT1R) inhibitor sacubitril/valsartan (SAC/VAL) may increase levels of these molecules and block AT1Rs required for ACE2 endocytosis in SARS-CoV-2 infection. Moreover, SAC/VAL has a positive impact on acute heart failure that is very frequently observed in deceased COVID-19 patients. The current review aims to summarize actual therapeutic strategies for COVID-19 and to examine the data supporting the potential benefits of SAC/VAL in COVID-19 treatment.

Rationale and design of the PRAETORIAN-COVID trial: A double-blind, placebo-controlled randomized clinical trial with valsartan for PRevention of Acute rEspiraTORy dIstress syndrome in hospitAlized patieNts with SARS-COV-2 Infection Disease.

There is much debate on the use of angiotensin receptor blockers (ARBs) in severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2)-infected patients. Although it has been suggested that ARBs might lead to a higher susceptibility and severity of SARS-CoV-2 infection, experimental data suggest that ARBs may reduce acute lung injury via blocking angiotensin-II-mediated pulmonary permeability, inflammation, and fibrosis. However, despite these hypotheses, specific studies on ARBs in SARS-CoV-2 patients are lacking. METHODS: The PRAETORIAN-COVID trial is a multicenter, double-blind, placebo-controlled 1:1 randomized clinical trial in adult hospitalized SARS-CoV-2-infected patients (n = 651). The primary aim is to investigate the effect of the ARB valsartan compared to placebo on the composite end point of admission to an intensive care unit, mechanical ventilation, or death within 14 days of randomization. The active-treatment arm will receive valsartan in a dosage titrated to blood pressure up to a maximum of 160 mg bid, and the placebo arm will receive matching placebo. Treatment duration will be 14 days, or until the occurrence of the primary end point or until hospital discharge, if either of these occurs within 14 days. The trial is registered at clinicaltrials.gov (NCT04335786, 2020). SUMMARY: The PRAETORIAN-COVID trial is a double-blind, placebo-controlled 1:1 randomized trial to assess the effect of valsartan compared to placebo on the occurrence of ICU admission, mechanical ventilation, and death in hospitalized SARS-CoV-2-infected patients. The results of this study might impact the treatment of SARS-CoV-2 patients globally.