Neprilysin inhibition does not alter dynamic of proenkephalin-A 119-159 and pro-substance P in heart failure

Endogenous opiates and behavior: 2021

This paper is the forty-fourth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2021 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonizts and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Proenkephalin as a Novel Prognostic Marker in Heart Failure Patients: A Systematic Review and Meta-Analysis

Over the last several years, the use of biomarkers in the diagnosis of patients with heart failure (HF) has skyrocketed. Natriuretic peptides are currently the most widely used biomarker in the diagnosis and prognosis of individuals with HF. Proenkephalin (PENK) activates delta-opioid receptors in cardiac tissue, resulting in a decreased myocardial contractility and heart rate. However, the goal of this meta-analysis is to evaluate the association between the PENK level at the time of admission and prognosis in patients with HF, such as all-cause mortality, rehospitalization, and decreasing renal function. High PENK levels have been associated with a worsened prognosis in patients with HF.

Neprilysin inhibition does not alter dynamic of proenkephalin-A 119-159 and pro-substance P in heart failure

AIMS

As NEP degrades many substrates, the specific therapeutic mechanism of NEP inhibition with angiotensin receptor neprilysin inhibitor (ARNi) in heart failure with reduced ejection fraction (HFrEF) is not entirely evident. The aim of this study was to investigate the response of two substrates of NEP-the tachykinin and enkephalin systems-to the initiation of ARNi therapy in HFrEF.

METHODS AND RESULTS

Between 2016 and 2018, 141 consecutive patients with stable HFrEF [74 with initiation of ARNi and 67 controls on continuous angiotensin converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) therapy] were prospectively enrolled. Plasma proenkephalin-A 119-159 (PENK) and pro-substance P (pro-SP) were serially determined. Proenkephalin-A 119-159 and pro-SP correlated strongly with each other (r_s  = 0.67, P < 0.001) and kidney function (r_s  = -0.66, P < 0.001 and r_s  = -0.54, P < 0.001) and modestly with NT-proBNP (r_s  = 0.32, P < 0.001 and r_s  = 0.24, P = 0.006, respectively). Concentrations of circulating PENK were slightly elevated after 1 and 2 year follow-up compared with baseline (BL) [BL median: 67.4 pmol/L (IQR: 57.3-89.8), 1 year: 83.5 pmol/L (IQR: 62.4-111.6), 2 years: 92.3 pmol/L (IQR: 63.1-101.9); BL vs. 1 year: P = 0.017 and BL vs. 2 years: P = 0.019] in the overall analysis, but lost significance at 2 year follow-up when assessed in paired subanalysis (P = 0.116). Plasma pro-SP levels remained comparable during the entire follow-up [BL median: 78.3 pmol/L (IQR: 67.9-90.6), 1 year: 75.9 pmol/L (IQR: 58.6-96.3), 2 years: 79.7 pmol/L (IQR: 59.9-105.3); P = ns for both timepoints]. Biomarker patterns of ARNi patients were independent from baseline therapy, that is, ACEi or ARB (P > 0.05 between groups).

CONCLUSIONS

Although enkephalins and SP are known substrates of NEP, NEP inhibition by ARNi does not clearly affect the circulating precursors PENK and pro-SP in HFrEF.