Proenkephalin in Heart Failure

Proenkephalin Levels and Its Determinants in Patients with End-Stage Kidney Disease Treated with Hemodialysis and Peritoneal Dialysis

Recently, proenkephalin A (PENK A) has been shown to reflect glomerular dysfunction and to predict new-onset acute kidney injury and heart failure. While previous studies have investigated PENK A as a biomarker in individuals with preserved renal function, PENK A concentration in patients with end-stage kidney disease (ESKD) was not investigated. Plasma PENK A concentration was assessed in 88 patients with ESKD treated with hemodialysis (HD) or peritoneal dialysis (PD), and its associations with kidney function and heart failure indicators were investigated. In HD patients, the difference in PENK A levels before and after hemodialysis, was measured and further assessed for an association with the type of HD membrane used. PENK A levels did not differ significantly between HD and PD patients. In HD patients, the median PENK A concentration was significantly higher before than after hemodialysis (1.368 vs. 2.061, p = 0.003). No correlation was found between PENK A level and urea (p = 0.192), eGFR (p = 0.922), dialysis vintage (p = 0.637), and residual urine output (p = 0.784). Heart failure (p = 0.961), EF (p = 0.361), and NT-proBNP (p = 0.949) were not associated with increased PENK A concentration. PENK A does not reflect renal function and cardiac status in patients with ESKD. Further research is required to establish the clinical utility of the new biomarker in patients with impaired kidney function.

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.

Advances in laboratory detection of acute kidney injury

Recent advances have improved our understanding of the epidemiology and pathophysiology of acute kidney injury (AKI). So far, the Kidney Disease: Improving Global Outcome guidelines define and stratify kidney injury based on increases in serum creatinine level and/or decreases in urine output. Although the term AKI acknowledges the existence of cellular injury, its diagnosis is still only defined by the reduced excretory function of the kidney. New biomarkers that aid a better understanding of the relationship between acute tubular injury and kidney dysfunction have been identified, reflecting the advances in molecular biology. The expression of some of these novel biomarkers precedes changes in conventional biomarkers or can increase their predictive power. Therefore, they might enhance the clinical accuracy of the definition of AKI. This review summarizes the limitations of the current AKI classification and a panel of candidate biomarkers for augmenting AKI classification and recognition of AKI subphenotypes. We expect that the integration of appropriately selected biomarkers in routine clinical practice can improve AKI care.

Proenkephalin and the risk of new-onset heart failure: data from prevention of renal and vascular end-stage disease

Background

Enkephalins of the opioid system exert several cardiorenal effects. Proenkephalin (PENK), a stable surrogate, is associated with heart failure (HF) development after myocardial infarction and worse cardiorenal function and prognosis in patients with HF. The association between plasma PENK concentrations and new‐onset HF in the general population remains to be established.

Hypothesis

We hypothesized that plasma PENK concentrations are associated with new‐onset HF in the general population.

Methods

We included 6677 participants from the prevention of renal and vascular end‐stage disease study and investigated determinants of PENK concentrations and their association with new‐onset HF (both reduced [HFrEF] and preserved ejection fraction [HFpEF]).

Results

Median PENK concentrations were 52.7 (45.1–61.9) pmol/L. Higher PENK concentrations were associated with poorer renal function and higher NT‐proBNP concentrations. The main determinants of higher PENK concentrations were lower estimated glomerular filtration rate (eGFR), lower urinary creatinine excretion, and lower body mass index (all p < .001). After a median 8.3 (7.8–8.8) years follow‐up, 221 participants developed HF; 127 HFrEF and 94 HFpEF. PENK concentrations were higher in subjects who developed HF compared with those who did not, 56.2 (45.2–67.6) versus 52.7 (45.1–61.6) pmol/L, respectively (p = .003). In competing‐risk analyses, higher PENK concentrations were associated with higher risk of new‐onset HF (hazard ratio [HR] = 2.09[1.47–2.97], p < .001), including both HFrEF (HR = 2.31[1.48–3.61], p < .001) and HFpEF (HR = 1.74[1.02–2.96], p = .042). These associations were, however, lost after adjustment for eGFR.

Conclusions

In the general population, higher PENK concentrations were associated with lower eGFR and higher NT‐proBNP concentrations. Higher PENK concentrations were not independently associated with new‐onset HFrEF and HFpEF and mainly confounded by eGFR.

Proenkephalin as a new biomarker for pediatric acute kidney injury - reference values and performance in children under one year of age

Objectives Acute kidney injury (AKI) is common in critically ill children, but current biomarkers are suboptimal. Proenkephalin A 119-159 (PENK) is a promising new biomarker for AKI in adults, but pediatric data is lacking. We determined PENK reference intervals for healthy children, crucial for clinical implementation, and explored concentrations in critically ill infants aged under 1 year. Methods Observational cohort study in healthy infants and critically ill children aged 0-1 years. Reference values were determined using generalized additive models. Plasma PENK concentrations between healthy children and critically ill children with and without AKI, were compared using linear mixed modelling. The performance of PENK as AKI biomarker was compared to cystatin C (CysC) and β-trace protein (BTP) using receiver-operating-characteristic (ROC) analysis. Results PENK concentrations in 100 healthy infants were stable during the first year of life (median 517.3 pmol/L). Median PENK concentrations in 91 critically ill children, were significantly higher in those with AKI (n=40) (KDIGO Stage 1 507.9 pmol/L, Stage 2 704.0 pmol/L, Stage 3 930.5 pmol/L) than non-AKI patients (n=51, 432.2 pmol/L) (p < 0.001). PENK appeared to relate better to AKI diagnosis than CysC and BTP (AUROC PENK 0.858, CysC 0.770 and BTP 0.711) in the first 24 h after recruitment. Conclusions PENK reference values are much higher in young infants than adults, but clearly discriminate between children with and without AKI, with comparable or better performance than CysC and BTP. Our results illustrate the importance of establishing age-normalized reference values and indicate PENK as a promising pediatric AKI biomarker.

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.

Pro B-type Natriuretic Peptide and Midregional Proadrenomedullin are Associated with Incident Carotid Stenosis During Long Term Follow-up

BACKGROUND

Plasma biomarkers may be useful to detect healthy individuals at increased risk for atherosclerotic manifestations, such as carotid artery stenosis. The aim of this longitudinal cohort study was to evaluate new biomarkers in relation to C-reactive protein and conventional risk factors for carotid artery stenosis during long term follow-up METHODS: The following markers were measured in 5550 middle-aged subjects: C-reactive protein, lipoprotein-associated phospholipase A2, proneurotensin, midregional pro-adrenomedullin, midregional pro-atrial natriuretic peptide, N-terminal pro B-type natriuretic peptide, copeptin, and cystatin C. Subjects with prevalent carotid artery stenosis were excluded. Subjects were followed in national patient registers for 23.4 (interquartile range 19.5-24.3) years regarding incident carotid artery stenosis, both operated and non-operated.

RESULTS

When including conventional risk markers in Cox regression, N-terminal pro B-type natriuretic peptide (Hazard ratio 1.36; 95% confidence interval 1.12-1.65; p = 0.002) was independently associated with incident carotid artery stenosis, whereas there were trends for C-reactive protein (HR 1.20; 95% confidence interval 0.98-1.48; p = 0.071), and midregional pro-adrenomedullin (Hazard ratio 1.21; 95% confidence interval 0.99-1.47; p = 0.061). Midregional pro-adrenomedullin (Hazard ratio 1.30; 95% confidence interval 1.03-1.65; p = 0.029) was independently associated with incident surgery for carotid artery stenosis, whereas there was a trend for N-terminal pro B-type natriuretic peptide (Hazard ratio 1.31; 95% confidence interval 1.00-1.72; p = 0.052).

CONCLUSIONS

N-terminal pro B-type natriuretic peptide and midregional pro-adrenomedullin can be used as predictors for clinically detected carotid artery stenosis during long-term follow-up of healthy subjects.

Copeptin, B-type natriuretic peptide and cystatin C are associated with incident symptomatic PAD

Purpose: The aim of this study is to evaluate plasma biomarkers as predictors for peripheral arterial disease (PAD). Materials and methods: Prospective longitudinal cohort study of middle-aged individuals from the cardiovascular cohort of the Malmö Diet and Cancer study (MDCS) (n = 5550; 1991-94). Cystatin C, copeptin, N-terminal pro-B-type natriuretic peptide (N-BNP), midregional proatrial natriuretic peptide (MR-proANP), mid-regional proadrenomedullin (MR-proADM), and conventional risk factors were measured at baseline. The diagnosis of symptomatic PAD was validated in 97% of the cases. Results: Cumulative incidence of PAD during median follow up of 23.4 years was 4.4% (men 5.9%, women 3.3%). Adjusted for age, sex, smoking, body mass index, hypertension, diabetes mellitus and total cholesterol, copeptin (hazard ratio [HR] 1.46; 95% confidence interval [CI] 1.19-1.80), N-BNP (HR 1.28; 95% CI 1.11-1.48), and cystatin C (HR 1.19; 95% CI 1.10-1.29) were independently associated with incident PAD. Subjects with the three biomarkers copeptin, N-BNP, and cystatin C in the highest quartiles, ran a high risk of incident PAD (HR 3.29; 95% CI 1.76-6.17) compared to those with no biomarker in the highest quartile. Conclusion: Copeptin, N-BNP, and cystatin C were associated with incident symptomatic PAD, implying that these biomarkers are sensitive indicators of early subclinical PAD. Clinical significance First prospective longitudinal cohort study evaluating Cystatin C, copeptin, N-terminal pro-B-type natriuretic peptide (N-BNP), midregional proatrial natriuretic peptide (MR-proANP), and mid-regional proadrenomedullin (MR-proADM) as predictors for peripheral arterial disease (PAD). Copeptin, N-BNP, and Cystatin C where independently associated with incident symptomatic PAD after adjustment for conventional risk factors. Copeptin, N-BNP, and Cystatin C seem to be sensitive indicators of early subclinical PAD.

Enkephalins and ACTH in the mammalian nervous system

The pentapeptides methionine-enkephalin and leucine-enkephalin belong to the opioid family of peptides, and the non-opiate peptide adrenocorticotropin hormone (ACTH) to the melanocortin peptide family. Enkephalins/ACTH are derived from pro-enkephalin, pro-dynorphin or pro-opiomelanocortin precursors and, via opioid and melanocortin receptors, are responsible for many biological activities. Enkephalins exhibit the highest affinity for the δ receptor, followed by the μ and κ receptors, whereas ACTH binds to the five subtypes of melanocortin receptor, and is the only member of the melanocortin family of peptides that binds to the melanocortin-receptor 2 (ACTH receptor). Enkephalins/ACTH and their receptors exhibit a widespread anatomical distribution. Enkephalins are involved in analgesia, angiogenesis, blood pressure, embryonic development, emotional behavior, feeding, hypoxia, limbic system modulation, neuroprotection, peristalsis, and wound repair; as well as in hepatoprotective, motor, neuroendocrine and respiratory mechanisms. ACTH plays a role in acetylcholine release, aggressive behavior, blood pressure, bone maintenance, hyperalgesia, feeding, fever, grooming, learning, lipolysis, memory, nerve injury repair, neuroprotection, sexual behavior, sleep, social behavior, tissue growth and stimulates the synthesis and secretion of glucocorticoids. Enkephalins/ACTH are also involved in many pathologies. Enkephalins are implicated in alcoholism, cancer, colitis, depression, heart failure, Huntington's disease, influenza A virus infection, ischemia, multiple sclerosis, and stress. ACTH plays a role in Addison's disease, alcoholism, cancer, Cushing's disease, dermatitis, encephalitis, epilepsy, Graves' disease, Guillain-Barré syndrome, multiple sclerosis, podocytopathies, and stress. In this review, we provide an updated description of the enkephalinergic and ACTH systems.

Preprodynorphin gene mutation causes progressive cardiac conduction disease: A whole-exome analysis of a pedigree

AIMS

Progressive cardiac conduction disease (PCCD) is a rare heart disease that usually shows familial inheritance. Potential genetic risk factors for PCCD have been mostly limited to genes that encode ion channels, cardiac transcription factors, T-box transcription factors, gap junction proteins, energy metabolism regulators and structural proteins.

MAIN METHODS

Subjects in the present study came from a family who exhibited the autosomal dominant inheritance of PCCD. The primary proband had syncope and an electrocardiogram typical for PCCD, which started in the left bundle branch block, and passed to the atrioventricular block. The patient received a permanent pacemaker in 2013. Pathogenic mutations in the proband's family were identified using whole-exome sequencing and Sanger sequencing.

KEY FINDINGS

The results for the family members were verified using Sanger sequencing, while the results for healthy unrelated individuals were verified using SNaPShot. All patients in the family shared two adjacent missense mutations in the preprodynorphin (PDYN) gene (c.581A > T, c.580G > C; p.D194L).

SIGNIFICANCE

The PDYN double mutation c.581A > T and c.580G > C (p.D194L) may be linked to the onset of familial PCCD. The effects of these mutations on electrophysiology require further investigation.

Proenkephalin and prognosis in heart failure with preserved ejection fraction: a GREAT network study

Background

Proenkephalin (PENK), a stable endogenous opioid biomarker related to renal function, has prognostic utility in acute and chronic heart failure. We investigated the prognostic utility of PENK in heart failure with preserved ejection fraction (HFpEF), and its relationship to renal function, Body Mass Index (BMI), and imaging measures of diastolic dysfunction.

Methods

In this multicentre study, PENK was measured in 522 HFpEF patients (ejection fraction > 50%, 253 male, mean age 76.13 ± 10.73 years) and compared to 47 age and sex-matched controls. The primary endpoint was 2-years composite of all-cause mortality and/or heart failure rehospitalisation (HF). A subset (n = 163) received detailed imaging studies.

Results

PENK levels were raised in HFpEF (median [interquartile range] 88.9 [62.1–132.0]) compared to normal controls (56.3 [47.9–70.5]). PENK was correlated to urea, eGFR, Body Mass Index and E/e′ (r_s 0.635, − 0.741, − 0.275, 0.476, respectively, p < 0.0005). During 2 years follow-up 144 patients died and 220 had death/HF endpoints. Multivariable Cox regression models showed PENK independently predicted 2 year death/HF [hazard ratio (for 1 SD increment of log-transformed biomarker) HR 1.45 [95% CI 1.12–1.88, p = 0.005]], even after adjustment for troponin (HR 1.59 [1.14–2.20, p = 0.006]), and Body Mass Index (HR 1.63 [1.13–2.33, p = 0.009]). PENK showed no interaction with ejection fraction status for prediction of poor outcomes. Net reclassification analyses showed PENK significantly improved classification of death/HF outcomes for multivariable models containing natriuretic peptide, troponin and Body Mass Index (p < 0.05 for all).

Conclusions

In HFpEF, PENK levels are related to BMI, and measures of diastolic dysfunction and are prognostic for all-cause mortality and heart failure rehospitalisation.

Electronic supplementary material

The online version of this article (10.1007/s00392-019-01424-y) contains supplementary material, which is available to authorized users.

Bioinformatics analysis of sex differences in arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited disease that exhibits sex differences on clinical presentation. The present study aimed to investigate the sex differences associated with ARVC by conducting an integrated bioinformatics analysis. The GSE29819 gene expression dataset was downloaded from the Gene Expression Omnibus database. The online analytical tool GEO2R was then used to screen for differentially expressed genes (DEGs), which were subsequently processed using enrichment analysis and protein‑protein interaction (PPI) network construction. Functional annotation of the DEGs was determined using ClueGO. The PPI network was constructed with Search Tool for the Retrieval of Interacting Genes, and was visualized with Cytoscape to identify the modules and hub genes. Compared with the female group, a total of 1,188 DEGs, of which 915 were upregulated and 273 were downregulated, were identified in the male group. The enrichment analysis revealed that in KEGG pathways, the upregulated DEGs were substantially enriched in the 'nicotine addiction' pathways, whereas the downregulated DEGS were mainly enriched in the 'ECM‑receptor interaction' and 'protein digestion and absorption' pathways. The PPI network contained 899 nodes and 1,627 edges, among which four significant modules were identified. In addition, kininogen 1, lysophosphatidic acid receptor 5, formyl peptide receptor (FPR) 2, adenylate cyclase 2, γ‑aminobutyric acid type B receptor subunit 2, FPR1, hydroxycarboxylic acid receptor 1, prostaglandin E receptor 3, cannabinoid receptor 1 and proenkephalin were identified as the top 10 hub genes. The key genes and related pathways identified in this study provide genetic insight into the diversity in phenotypes between female and male patients with ARVC, and may facilitate therapeutic individualization.