Caspase-1 transcripts in failing human heart after mechanical unloading

Elevated Plasma Immunoglobulin Levels Prior to Heart Transplantation Are Associated with Poor Post-Transplantation Survival

Cardiac allograft vasculopathy (CAV) and antibody-mediated rejection are immune-mediated, long-term complications that jeopardize graft survival after heart transplantation (HTx). Interestingly, increased plasma levels of immunoglobulins have been found in end-stage heart failure (HF) patients prior to HTx. In this study, we aimed to determine whether increased circulating immunoglobulin levels prior to transplantation are associated with poor post-HTx survival. Pre-and post-HTx plasma samples of 36 cardiac transplant recipient patients were used to determine circulating immunoglobulin levels. In addition, epicardial tissue was collected to determine immunoglobulin deposition in cardiac tissue and assess signs and severity of graft rejection. High levels of IgG1 and IgG2 prior to HTx were associated with a shorter survival post-HTx. Immunoglobulin deposition in cardiac tissue was significantly elevated in patients with a survival of less than 3 years. Patients with high plasma IgG levels pre-HTx also had significantly higher plasma levels after HTx. Furthermore, high pre-HTX levels of IgG1 and IgG2 levels were also significantly increased in patients with inflammatory infiltrate in CAV lesions. Altogether the results of this proof-of-concept study suggest that an activated immune response prior to transplantation negatively affects graft survival.

Transcriptional evaluation of relaxin and endothelin-1 axis in heart failure patients: First evidence of its involvement during left ventricular assist device support

BACKGROUND

Left ventricular assist devices (LVAD) are implanted in patients with end-stage heart failure (ESHF) as a mechanical support for the failing myocardium, which is characterized by an activation of the neuro-hormonal system, with release of vasoactive mediators, such as endothelin (ET)-1 and relaxin (RLX)-2. The aim of this study was to evaluate whether LVAD is able to modulate the RLX-2 and ET-1 system expression in ESHF patients.

METHODS

Cardiac tissue was collected from ESHF patients before LVAD implantation (pre-LVAD group, n = 22), at the time of cardiac transplantation with concomitant LVAD removal (post-LVAD group, n = 6), and from stable HF patients on medical therapy at the time of cardiac transplantation (HTx group, n = 7). The expression of RLX-2, ET-1 system and inflammatory markers (IL-8, IL-6, TNF-α) were evaluated by Real-Time PCR.

RESULTS

RLX-2 mRNA resulted similar in pre-LVAD and HTx, but it was significantly increased in post-LVAD (p = 0.02/p = 0.01 respectively). A similar trend was observed for ET-1 and ET-converting enzyme (ECE)-1 while no significant difference was observed for ET-receptors. A positive correlation was found between ET-1 and ET-A (p = 0.031) and ECE-1 (p < 0.0001). The inflammatory markers resulted activated in all the three groups. A significant correlation between RLX-2 and ET-1 in pre-LVAD, as well as between RLX-2 and IL-8/IL-6, was found.

CONCLUSIONS

Our research investigates for the first time the involvement of RLX-2 and ET-1 system in ESHF patients supported by LVAD, demonstrating their potential ability to partially recover the failing myocardium, indicating their possible clinical role as biomarkers or pharmacological agents in LVAD patients.

TRANSLATIONAL ASPECT

The study of novel biomarkers in patients supported by continuous axial flow devices may be a starting point analysis applicable to patients with centrifugal flow devices.

Cardiac unloading by LVAD support differentially influences components of the cGMP-PKG signaling pathway in ischemic and dilated cardiomyopathy

Implantation of left ventricular assist devices (LVADs) as bridge to transplant in end-stage heart failure allows for analyzing reverse remodeling processes of the supported heart. Whether this therapy influences the cGMP-PKG signaling pathway, which is currently under thorough investigation for developing new heart failure therapeutics, is unknown. In fourteen end-stage heart failure patients (8 with dilated cardiomyopathy, DCM; 6 with ischemic cardiomyopathy, ICM) tissue specimens of left ventricles were collected at LVAD implantation and afterwards at receiver heart explantation, respectively. Then the expressions of key components of the cGMP-PKG signaling pathway were determined by polymerase chain reaction (ANP; BNP; natriuretic peptide receptor A, NPR-A; natriuretic peptide receptor C, NPR-C; neprilysin; NOS3; soluble guanylyl cyclase, sGC; PDE5; cGMP-dependent protein kinase G, PKG) and enzyme-linked immunosorbent assay (cGMP), respectively. Patients were predominantly male, 52 ± 10 years old, were receiving recommended heart failure therapy, and had their donor organ implanted after 351 ± 317 days of LVAD support. Except for more DCM patients with ICD therapy, no significant differences were detected between ICM and DCM, which also applies to the expression of cGMP-PKG pathway components at baseline. After LVAD support, ANP, NPR-C, and cGMP were significantly down-regulated and neprilysin, PDE5, and PKG I expressions were reduced with borderline significance in DCM, but not in ICM patients. Multiple significant correlations were found for expression differences (i.e., expression at LVAD implantation minus expression at heart transplantation) both in DCM and ICM, even though there was a closer connection between the NO and NP side of the cGMP-PKG pathway in DCM patients. Furthermore, duration of LVAD support negatively correlated with expression differences of PKG I, PDE5, and sGC in ICM, but not in DCM. Originating from the same activation level at LVAD implantation, cardiac unloading significantly alters key components of the cGMP-PKG pathway in DCM, but not in ICM patients. This etiology-specific regulation should be considered when analyzing therapeutic interventions with effects on this signaling pathway.

Chronic heart failure: Ca(2+), catabolism, and catastrophic cell death

Robust successes have been achieved in recent years in conquering the acutely lethal manifestations of heart disease. Many patients who previously would have died now survive to enjoy happy and productive lives. Nevertheless, the devastating impact of heart disease continues unabated, as the spectrum of disease has evolved with new manifestations. In light of this ever-evolving challenge, insights that culminate in novel therapeutic targets are urgently needed. Here, we review fundamental mechanisms of heart failure, both with reduced (HFrEF) and preserved (HFpEF) ejection fraction. We discuss pathways that regulate cardiomyocyte remodeling and turnover, focusing on Ca(2+) signaling, autophagy, and apoptosis. In particular, we highlight recent insights pointing to novel connections among these events. We also explore mechanisms whereby potential therapeutic approaches targeting these processes may improve morbidity and mortality in the devastating syndrome of heart failure.

Increased B-type-natriuretic peptide promotes myocardial cell apoptosis via the B-type-natriuretic peptide/long non-coding RNA LSINCT5/caspase-1/interleukin 1β signaling pathway

Chronic heart failure (CHF) is the final stage of various heart diseases, and is increasingly recognized as a major health problem in the elderly. Previous studies demonstrated that B-type-natriuretic peptide (BNP) is an established biomarker of CHF. Furthermore, BNP also regulates cell proliferation, differentiation and apoptosis. Recent evidence has revealed that BNP affects myocardial cell apoptosis during myocardial ischemia-reperfusion injury. Long non-coding RNAs (lncRNAs) are emerging as novel molecular compounds involved in gene regulation, and have important roles in numerous human diseases. However, the mechanism underlying the BNP and lncRNA-induced regulation of myocardial cell apoptosis remains to be elucidated. The present study reported that lncRNA LSINCT5, upregulated by BNP, is able to regulate myocardial cell apoptosis via the activation of the caspase-1/interleukin (IL)-1β signaling pathway. BNP-induced apoptosis of HCM cells was observed using flow cytometry, and involved caspase-1. In addition, expression profiling using a human lncRNA polymerase chain reaction array revealed that LSINCT5 was highly expressed in BNP-treated myocardial cells, as compared with untreated cells. The role of lncRNA LSINCT5 in HCM cell apoptosis was also investigated. The results of the present study indicated that LSINCT5 silencing by small interfering RNA inhibits caspase-1/IL-1β signaling, and suppresses apoptosis in BNP-treated HCM cells. Therefore, high expression levels of BNP promote the apoptosis of myocardial cells through the lncRNA LSINCT5 mediator, which activates the caspase-1/IL-1β signaling pathway. These findings uncovered a novel pathogenic mechanism, and provided a potential therapeutic target for CHF.