Dataset Information

Effects of BNP and Sacubitrilat/Valsartan on Atrial Functional Reserve and Arrhythmogenesis in Human Myocardium.

ABSTRACT:

Background

Although the angiotensin receptor-neprilysin inhibitor (ARNI) sacubitril/valsartan started a new era in heart failure (HF) treatment, less is known about the tissue-level effects of the drug on the atrial myocardial functional reserve and arrhythmogenesis.

Methods and results

Right atrial (RA) biopsies were retrieved from patients (n = 42) undergoing open-heart surgery, and functional experiments were conducted in muscle strips (n = 101). B-type natriuretic peptide (BNP) did not modulate systolic developed force in human myocardium during β-adrenergic stimulation, but it significantly reduced diastolic tension (p < 0.01) and the probability of arrhythmias (p < 0.01). In addition, patient's plasma NTproBNP positively correlated with isoproterenol-induced contractile reserve in atrial tissue in vitro (r = 0.65; p < 0.01). Sacubitrilat+valsartan (Sac/Val) did not show positive inotropic effects on atrial trabeculae function but reduced arrhythmogeneity. Atrial and ventricular biopsies from patients with end-stage HF (n = 10) confirmed that neprilysin (NEP) is equally expressed in human atrial and ventricular myocardium. RA NEP expression correlates positively with RA ejection fraction (EF) (r = 0.806; p < 0.05) and left ventricle (LV) NEP correlates inversely with left atrial (LA) volume (r = -0.691; p < 0.05).

Conclusion

BNP ameliorates diastolic tension during adrenergic stress in human atrial myocardium and may have positive long-term effects on the inotropic reserve. BNP and Sac/Val reduce atrial arrhythmogeneity during adrenergic stress in vitro. Myocardial NEP expression is downregulated with declining myocardial function, suggesting a compensatory mechanism in HF.

SUBMITTER: Primessnig U

PROVIDER: S-EPMC9294287 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Effects of BNP and Sacubitrilat/Valsartan on Atrial Functional Reserve and Arrhythmogenesis in Human Myocardium.

Primessnig Uwe U Deißler Peter M PM Wakula Paulina P Tran Khai Liem KL Hohendanner Felix F von Lewinski Dirk D Blaschke Florian F Knosalla Christoph C Falk Volkmar V Pieske Burkert B Grubitzsch Herko H Heinzel Frank R FR

Frontiers in cardiovascular medicine 20220705

<h4>Background</h4>Although the angiotensin receptor-neprilysin inhibitor (ARNI) sacubitril/valsartan started a new era in heart failure (HF) treatment, less is known about the tissue-level effects of the drug on the atrial myocardial functional reserve and arrhythmogenesis.<h4>Methods and results</h4>Right atrial (RA) biopsies were retrieved from patients (<i>n</i> = 42) undergoing open-heart surgery, and functional experiments were conducted in muscle strips (<i>n</i> = 101). B-type natriureti ...[more]

PMID: 35865376

Similar Datasets

Project description:Background: Obesity can influence the structure and function of the atrium, but most studies focused on the relationship of body mass index (BMI) and overt left atrium (LA) dysfunction as assessed by clinical imaging. We combined the assessment of right atrium (RA) function in vivo and in vitro in obese and non-obese patients scheduled for elective cardiac surgery. Methods: Atrial structure and function were quantified pre-operatively by echocardiography. RA tissue removed for the establishment of extracorporeal support was collected and RA trabeculae function was quantified in vitro at baseline and with adrenergic stimulation (isoproterenol). Fatty acid-binding protein 3 (FABP3) was quantified in RA tissue. Results were stratified according to the BMI of the patients. Results: About 76 patients were included pre-operatively for the echocardiographic analysis. RA trabeculae function at baseline was finally quantified from 46 patients and RA function in 28 patients was also assessed with isoproterenol. There was no significant correlation between BMI and the parameters of atrial function measured by the clinical echocardiography. However, in vitro measurements revealed a significant correlation between BMI and a prolonged relaxation of the atrial myocardium at baseline, which persisted after controlling for the atrial fibrillation and diabetes by the partial correlation analysis. Acceleration of relaxation with isoproterenol was significantly lower in the obese group (BMI ≥ 30 kg/m2). As a result, relaxation with adrenergic stimulation in the obese group remained significantly higher compared to the overweight group (25 kg/m2 ≤ BMI < 30 kg/m2, p = 0.027) and normal group (18.5 kg/m2 ≤ BMI < 25 kg/m2, p = 0.036). There were no differences on impacts of the isoproterenol on (systolic) developed force between groups. The expression of FABP3 in the obese group was significantly higher compared to the normal group (p = 0.049) and the correlation analysis showed the significant correlations between the level of FABP3 in the RA trabeculae function. Conclusion: A higher BMI is associated with the early subclinical changes of RA myocardial function with the slowed relaxation and reduced adrenergic lusitropy.

Project description:Organotypic culture of human ventricular myocardium is emerging in basic and translational cardiac research. However, few institutions have access to human ventricular tissue, whereas atrial tissue is more commonly available and important for studying atrial physiology. This study presents a method for long-term cultivation of beating human atrial myocardium. After written informed consent, tissues from the right-atrial appendage were obtained from patients with sinus rhythm undergoing open heart surgery with cardiopulmonary bypass. Trabeculae (pectinate muscles) prepared from the samples were installed into cultivation chambers at 37°C with a diastolic preload of 500 μN. After 2 days with 0.5 Hz pacing, stimulation frequency was set to 1 Hz. Contractile force was monitored continuously. Beta-adrenergic response, refractory period (RP) and maximum captured frequency (fmax) were assessed periodically. After cultivation, viability and electromechanical function were investigated, as well as the expression of several genes important for intracellular Ca2+ cycling and electrophysiology. Tissue microstructure was analyzed by confocal microscopy. We cultivated 19 constantly beating trabeculae from 8 patient samples for 12 days and 4 trabeculae from 3 specimen for 21 days. Functional parameters were compared directly after installation (0 d) with those after 12 d in culture. Contraction force was 384 ± 69 μN at 0 d and 255 ± 90 μN at 12 d (p = 0.8, n = 22), RP 480 ± 97 ms and 408 ± 78 ms (p = 0.3, n = 9), fmax 3.0 ± 0.5 Hz and 3.8 ± 0.5 Hz (p = 0.18, n = 9), respectively. Application of 100 nM isoprenaline to 11 trabeculae at 7 d increased contraction force from 168 ± 35 μN to 361 ± 60 μN (p < 0.01), fmax from 6.4 ± 0.6 Hz to 8.5 ± 0.4 Hz (p < 0.01) and lowered RP from 319 ± 22 ms to 223 ± 15 ms. CACNA1c (L-type Ca2+ channel subunit) and GJA1 (connexin-43) mRNA expressions were not significantly altered at 12 d vs 0 d, while ATP2A (SERCA) and KCNJ4 (Kir2.3) were downregulated, and KCNJ2 (Kir2.1) was upregulated. Simultaneous Ca2+ imaging and force recording showed preserved excitation-contraction coupling in cultivated trabeculae. Confocal microscopy indicated preserved cardiomyocyte structure, unaltered amounts of extracellular matrix and gap junctions. MTT assays confirmed viability at 12 d. We established a workflow that allows for stable cultivation and functional analysis of beating human atrial myocardium for up to 3 weeks. This method may lead to novel insights into the physiology and pathophysiology of human atrial myocardium.

Project description:BackgroundEarlier studies showed that measured changes in plasma B-type natriuretic peptide (BNP) levels are inconsistent after sacubitril/valsartan administration. The reason remains unknown but may reflect the fact that BNP immunoreactivity measured with commercial BNP assays (BNPcom) includes both mature BNP and proBNP, and neprilysin degrades only mature BNP. In addition, the responsiveness to sacubitril/valsartan varies among patients with heart failure. We investigated the mechanism underlying the inconsistency of BNP measurements after sacubitril/valsartan.MethodsWe measured plasma mature BNP, proBNP and total BNP (mature BNP+proBNP) levels with our immunochemiluminescent assay as well as NT-proBNP, A-type natriuretic peptide (ANP) and BNPcom with conventional assays in 54 patients with heart failure, before (baseline) and after 2, 4, 8 and 12 weeks of sacubitril/valsartan administration. Responders were defined as having NT-proBNP levels at <70% of baseline after 12 weeks.ResultsAmong all patients, total BNP and BNPcom did not change with sacubitril/valsartan treatment, whereas NT-proBNP and proBNP decreased, mature BNP modestly increased and ANP greatly increased. Responders (n=31) exhibited smaller %changes in all natriuretic peptide levels than non-responders (n=23; all p<0.01). Receiver operating characteristic curves analysis to assess the ability of the %change in each natriuretic peptide at 4 weeks to detect responders showed that the area under the curve was about 0.80 for each peptide. There were good correlations between plasma natriuretic peptides levels at baseline and throughout the sacubitril/valsartan administration.ConclusionThese results suggest that the magnitude and direction of change in each BNP form depends on its substrate specificity for neprilysin, that differences in plasma levels of each BNP form between responders and non-responders appear early and persist and that BNPcom levels at 4 weeks can be applicable to prediction of the responders. Notably, our findings show that the idea that BNPcom cannot be used as a marker of heart failure after sacubitril/valsartan should be reconsidered.

Project description:Pharmacologic approaches for the treatment of atrial arrhythmias are limited due to side effects and low efficacy. Thus, the identification of new antiarrhythmic targets is of clinical interest. Recent genome studies suggested an involvement of SCN10A sodium channels (NaV1.8) in atrial electrophysiology. This study investigated the role and involvement of NaV1.8 (SCN10A) in arrhythmia generation in the human atria and in mice lacking NaV1.8. NaV1.8 mRNA and protein were detected in human atrial myocardium at a significant higher level compared to ventricular myocardium. Expression of NaV1.8 and NaV1.5 did not differ between myocardium from patients with atrial fibrillation and sinus rhythm. To determine the electrophysiological role of NaV1.8, we investigated isolated human atrial cardiomyocytes from patients with sinus rhythm stimulated with isoproterenol. Inhibition of NaV1.8 by A-803467 or PF-01247324 showed no effects on the human atrial action potential. However, we found that NaV1.8 significantly contributes to late Na+ current and consequently to an increased proarrhythmogenic diastolic sarcoplasmic reticulum Ca2+ leak in human atrial cardiomyocytes. Selective pharmacological inhibition of NaV1.8 potently reduced late Na+ current, proarrhythmic diastolic Ca2+ release, delayed afterdepolarizations as well as spontaneous action potentials. These findings could be confirmed in murine atrial cardiomyocytes from wild-type mice and also compared to SCN10A-/- mice (genetic ablation of NaV1.8). Pharmacological NaV1.8 inhibition showed no effects in SCN10A-/- mice. Importantly, in vivo experiments in SCN10A-/- mice showed that genetic ablation of NaV1.8 protects against atrial fibrillation induction. This study demonstrates that NaV1.8 is expressed in the murine and human atria and contributes to late Na+ current generation and cellular arrhythmogenesis. Blocking NaV1.8 selectively counteracts this pathomechanism and protects against atrial arrhythmias. Thus, our translational study reveals a new selective therapeutic target for treating atrial arrhythmias.

Project description:(1) Background: Previous studies showed left ventricular (LV) and left atrial (LA) improvement and reverse remodeling after therapy with Sacubitril/Valsartan (S/V) in patients affected by heart failure with reduced ejection fraction (HFrEF). Therefore, we sought to investigate predictors of LA structural and functional reverse remodeling (LARR) in this setting of patients after therapy with S/V, focusing on left atrial strain parameters, such as peak atrial longitudinal strain (PALS). (2) Methods: Patients with HFrEF underwent clinical and echocardiographic evaluation at baseline and after six months of therapy with S/V. Measures of LA structure (LA volume index, LAVi) and function (LA emptying fraction (LAEF), PALS, LA conduit strain and peak atrial contraction strain (PACS) were also analyzed. Patients were divided in two groups, those with a LARR (relative reduction in LAVi > 15%, LARR+) and those without (LARR-). (3) Results: A total of 47 consecutive patients (66 ± 8 years, 85% male, mean LVEF 28 ± 6%) were enrolled in the study and followed up. A significant increase of LAEF (46 ± 13 vs. 37 ± 11%, p < 0.001) and a significant reduction of LAVi (42 ± 15 vs. 45 ± 15 mL/m2, p = 0.008) were found after 6 months of S/V therapy; 47% of the population showed LA reverse remodeling. LA strain parameters, PALS (19 ± 8 vs. 15 ± 7 %, p < 0.001) and LA conduit (-9.7 ± 5.2% vs. -7.6 ± 4.1%, p = 0.007) significantly improved after 6 months of S/V therapy. At multivariable stepwise regression analysis, changes in LV End Diastolic Volume (LVEDV) and PALS were significantly proportional to changes in LAVi values. (4) Conclusions: Six months of treatment with S/V in patients with HFrEF was associated with an improvement in LA functional reverse remodeling in a real-world scenario. LARR was not significantly correlated to baseline echocardiographic variables, but was proportional to changes in LV volumes and LA strain parameters. Finally, after S/V therapy, a strict connection between LA and LV reverse remodeling and between LA anatomical and functional reverse remodeling seems to be outlined.

Dataset Information

Effects of BNP and Sacubitrilat/Valsartan on Atrial Functional Reserve and Arrhythmogenesis in Human Myocardium.

Background

Methods and results

Conclusion

Publications

Effects of BNP and Sacubitrilat/Valsartan on Atrial Functional Reserve and Arrhythmogenesis in Human Myocardium.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets