Sacubitril/Valsartan, proved superiority over other conventional heart failure management treatments, but its mechanisms of action remains obscure. In this study, we sought to explore the mechanistic details for Sacubitril/Valsartan in heart failure and post-myocardial infarction remodeling, using an in silico, systems biology approach. Myocardial transcriptome obtained in response to myocardial infarction in swine was analyzed to address post-infarction ventricular remodeling. Swine transcriptome hits were mapped to their human equivalents using Reciprocal Best (blast) Hits, Gene Name Correspondence, and InParanoid database. Heart failure remodeling was studied using public data available in gene expression omnibus (accession GSE57345, subseries GSE57338), processed using the GEO2R tool. Using the Therapeutic Performance Mapping System technology, dedicated mathematical models trained to fit a set of molecular criteria, defining both pathologies and including all the information available on Sacubitril/Valsartan, were generated. All relationships incorporated into the biological network were drawn from public resources (including KEGG, REACTOME, INTACT, BIOGRID, and MINT). An artificial neural network analysis revealed that Sacubitril/Valsartan acts synergistically against cardiomyocyte cell death and left ventricular extracellular matrix remodeling via eight principal synergistic nodes. When studying each pathway independently, Valsartan was found to improve cardiac remodeling by inhibiting members of the guanine nucleotide-binding protein family, while Sacubitril attenuated cardiomyocyte cell death, hypertrophy, and impaired myocyte contractility by inhibiting PTEN. The complex molecular mechanisms of action of Sacubitril/Valsartan upon post-myocardial infarction and heart failure cardiac remodeling were delineated using a systems biology approach. Further, this dataset provides pathophysiological rationale for the use of Sacubitril/Valsartan to prevent post-infarct remodeling.

Atrial fibrillation (AF) is associated with abnormal sarcoplasmic reticulum (SR) calcium release, which is promoted by adenosine A_2A receptor (A_2AR) activation. Here, we tested the hypothesis that abnormal calcium release in AF is linked to A_2AR remodelling. Western blotting and quantitative real-time PCR were used to determine A_2AR mRNA and protein levels in right atrial samples from patients with and without AF. Effects of A_2AR activation on calcium handling were assessed with patch-clamp technique and confocal calcium imaging. A_2AR mRNA levels and functional A_2ARs were moderately up-regulated in patients with atrial dilation and markedly up-regulated in those with AF. Accordingly, A_2AR stimulation significantly increased ryanodine receptor phosphorylation in AF patients, and spontaneous calcium waves increased moderately in myocytes from patients with atrial dilation and strongly in patients with AF (2.2 ± 2.1 to 14.3 ± 8.8 min⁻¹, n = 6, P = 0.01). Moreover, the high baseline level of calcium waves in AF was reduced by A_2AR antagonists (3.5 ± 2.0 to 1.3 ± 1.3 min⁻¹, n = 6, P = 0.007) or adenosine deaminase (1.7 ± 1.5 to 0.5 ± 0.6 min⁻¹, n = 10, P = 0.02) suggesting that A_2ARs are activated by endogenous adenosine. Indeed, intracellular perfusion with adenosine significantly increased the calcium wave frequency (1.1 ± 0.8 to 8.2 ± 3.3 min⁻¹, n = 8), whereas adenosine removal from the cytosol decreased it (2.1 ± 0.9 to 0.3 ± 0.3 min⁻¹, n = 8, P = 0.04). Atrial fibrillation patients show increased A_2AR expression that may account for the high baseline level of spontaneous SR calcium release seen in myocytes from these patients, and the ability of A_2AR antagonists to reduce this abnormal calcium release points to the A_2AR as a novel molecular target in AF.

Stem cell therapies are promising strategies to regenerate human injured tissues, including ischemic myocardium. Here, we examined the acquisition of properties associated with vascular growth by human umbilical cord blood-derived mesenchymal stem cells (UCBMSCs), and whether they promoted vascular growth in vivo. UCBMSCs were induced in endothelial cell-specific growth medium (EGM-2) acquiring new cell markers, increased Ac-LDL uptake, and migratory capacity as assessed by qRT-PCR, Western blotting, indirect immunofluorescence, and invasion assays. Angiogenic and vasculogenic potentials could be anticipated by in vitro experiments showing self organization into Matrigel-mediated cell networks, and activation of circulating angiogenic-supportive myeloid cells. In mice, following subcutaneous co-injection with Matrigel, UCBMSCs modified to co-express bioluminescent (luciferases) and fluorescent proteins were demonstrated to participate in the formation of new microvasculature connected with the host circulatory system. Response of UCBMSCs to ischemia was explored in a mouse model of acute myocardial infarction (MI). UCBMSCs transplanted using a fibrin patch survived 4 weeks post-implantation and organized into CD31⁺network structures above the infarcted myocardium. MI-treated animals showed a reduced infarct scar and a larger vessel-occupied area in comparison with MI-control animals. Taken together, the presented results show that UCBMSCs can be induced in vitro to acquire angiogenic and vasculogenic properties and contribute to vascular growth in vivo.

The administration of extracellular vesicles (EV) from mesenchymal stromal cells (MSC) is a promising cell-free nanotherapy for tissue repair after myocardial infarction (MI). However, the optimal EV delivery strategy remains undetermined. Here, we designed a novel MSC-EV delivery, using 3D scaffolds engineered from decellularised cardiac tissue as a cell-free product for cardiac repair. EV from porcine cardiac adipose tissue-derived MSC (cATMSC) were purified by size exclusion chromatography (SEC), functionally analysed and loaded to scaffolds. cATMSC-EV markedly reduced polyclonal proliferation and pro-inflammatory cytokines production (IFNγ, TNFα, IL12p40) of allogeneic PBMC. Moreover, cATMSC-EV recruited outgrowth endothelial cells (OEC) and allogeneic MSC, and promoted angiogenesis. Fluorescently labelled cATMSC-EV were mixed with peptide hydrogel, and were successfully retained in decellularised scaffolds. Then, cATMSC-EV-embedded pericardial scaffolds were administered in vivo over the ischemic myocardium in a pig model of MI. Six days from implantation, the engineered scaffold efficiently integrated into the post-infarcted myocardium. cATMSC-EV were detected within the construct and MI core, and promoted an increase in vascular density and reduction in macrophage and T cell infiltration within the damaged myocardium. The confined administration of multifunctional MSC-EV within an engineered pericardial scaffold ensures local EV dosage and release, and generates a vascularised bioactive niche for cell recruitment, engraftment and modulation of short-term post-ischemic inflammation.