Alginate sulfate-nanoparticles loaded with hepatocyte growth factor and insulin-like growth factor-1 improve left ventricular repair in a porcine model of myocardial ischemia reperfusion injury.

Nanomedicine offers great potential for the treatment of cardiovascular disease and particulate systems have the capacity to markedly improve bioavailability of therapeutics. The delivery of pro-angiogenic hepatocyte growth factor (HGF) and pro-survival and pro-myogenic insulin-like growth factor (IGF-1) encapsulated in Alginate-Sulfate nanoparticles (AlgS-NP) might improve left ventricular (LV) functional recovery after myocardial infarction (MI). In a porcine ischemia-reperfusion model, MI is induced by 75 min balloon occlusion of the mid-left anterior descending coronary artery followed by reperfusion. After 1 week, pigs (n = 12) with marked LV-dysfunction (LV ejection fraction, LVEF < 45%) are randomized to fusion imaging-guided intramyocardial injections of 8 mg AlgS-NP prepared with 200 µg HGF and IGF-1 (HGF/IGF1-NP) or PBS (Control). Intramyocardial injection is safe and pharmacokinetic studies of Cy5-labeled NP confirm superior cardiac retention compared to intracoronary infusion. Seven weeks after intramyocardial-injection of HGF/IGF1-NP, infarct size, measured using magnetic resonance imaging, is significantly smaller than in controls and is associated with increased coronary flow reserve. Importantly, HGF/IGF1-NP-treated pigs show significantly increased LVEF accompanied by improved myocardial remodeling. These findings demonstrate the feasibility and efficacy of using AlgS-NP as a delivery system for growth factors and offer the prospect of innovative treatment for refractory ischemic cardiomyopathy.

Clec4e-Receptor Signaling in Myocardial Repair After Ischemia-Reperfusion Injury.

The bacterial C-type lectin domain family 4 member E (CLEC4E) has an important role in sterile inflammation, but its role in myocardial repair is unknown. Using complementary approaches in porcine, murine, and human samples, we show that CLEC4E expression levels in the myocardium and in blood correlate with the extent of myocardial injury and left ventricular (LV) functional impairment. CLEC4E expression is markedly increased in the vasculature, cardiac myocytes, and infiltrating leukocytes in the ischemic heart. Loss of Clec4e signaling is associated with reduced acute cardiac injury, neutrophil infiltration, and infarct size. Reduced myocardial injury in Clec4e -/- translates into significantly improved LV structural and functional remodeling at 4 weeks' follow-up. The early transcriptome of LV tissue from Clec4e -/- mice versus wild-type mice reveals significant upregulation of transcripts involved in myocardial metabolism, radical scavenging, angiogenesis, and extracellular matrix organization. Therefore, targeting CLEC4E in the early phase of ischemia-reperfusion injury is a promising therapeutic strategy to modulate myocardial inflammation and enhance repair after ischemia-reperfusion injury.

Cardiac Microvascular Endothelial Cells in Pressure Overload-Induced Heart Disease.

BACKGROUND: Chronic pressure overload predisposes to heart failure, but the pathogenic role of microvascular endothelial cells (MiVEC) remains unknown. We characterized transcriptional, metabolic, and functional adaptation of cardiac MiVEC to pressure overload in mice and patients with aortic stenosis (AS). METHODS: In Tie2-Gfp mice subjected to transverse aortic constriction or sham surgery, we performed RNA sequencing of isolated cardiac Gfp+-MiVEC and validated the signature in freshly isolated MiVEC from left ventricle outflow tract and right atrium of patients with AS. We next compared their angiogenic and metabolic profiles and finally correlated molecular and pathological signatures with clinical phenotypes of 42 patients with AS (50% women). RESULTS: In mice, transverse aortic constriction induced progressive systolic dysfunction, fibrosis, and reduced microvascular density. After 10 weeks, 25 genes predominantly involved in matrix-regulation were >2-fold upregulated in isolated MiVEC. Increased transcript levels of Cartilage Intermediate Layer Protein (Cilp), Thrombospondin-4, Adamtsl-2, and Collagen1a1 were confirmed by quantitative reverse transcription polymerase chain reaction and recapitulated in left ventricle outflow tract-derived MiVEC of AS (P<0.05 versus right atrium-MiVEC). Fatty acid oxidation increased >2-fold in left ventricle outflow tract-MiVEC, proline content by 130% (median, IQR, 58%-474%; P=0.008) and procollagen secretion by 85% (mean [95% CI, 16%-154%]; P<0.05 versus right atrium-MiVEC for all). The altered transcriptome in left ventricle outflow tract-MiVEC was associated with impaired 2-dimensional-vascular network formation and 3-dimensional-spheroid sprouting (P<0.05 versus right atrium-MiVEC), profibrotic ultrastructural changes, and impaired diastolic left ventricle function, capillary density and functional status, especially in female AS. CONCLUSIONS: Pressure overload induces major transcriptional and metabolic adaptations in cardiac MiVEC resulting in excess interstitial fibrosis and impaired angiogenesis. Molecular rewiring of MiVEC is worse in women, compromises functional status, and identifies novel targets for intervention.

Peripheral Blood RNAs and Left Ventricular Dysfunction after Myocardial Infarction: Towards Translation into Clinical Practice.

The treatment and early outcome of patients with acute myocardial infarction (MI) have dramatically improved the past decades, but the incidence of left ventricular (LV) dysfunction post-MI remains high. Peripheral blood RNAs reflect pathophysiological changes during acute MI and the inflammatory process. Therefore, these RNAs are promising new markers to molecularly phenotype patients and improve the early identification of patients at risk of subsequent LV dysfunction. We here discuss the coding and long non-coding RNAs that can be measured in peripheral blood of patients with acute MI and list the advantages and limitations for implementation in clinical practice. Although some studies provide preliminary evidence of their diagnostic and prognostic potential, the use of these makers has not yet been implemented in clinical practice. The added value of RNAs to improve treatment and outcome remains to be determined in larger clinical studies. International consortia are now catalyzing renewed efforts to investigate novel RNAs that may improve post-MI outcome in a precision-medicine approach. Graphical Abstract Peripheral blood RNAs reflect the inflammatory changes in acute MI. A number of studies provide preliminary evidence of their prognostic potential, although the use of these makers has not yet been assessed in clinical practice.

Peripheral Blood RNA Levels of QSOX1 and PLBD1 Are New Independent Predictors of Left Ventricular Dysfunction After Acute Myocardial Infarction.

BACKGROUND: The identification of patients with acute myocardial infarction (MI) at risk of subsequent left ventricular (LV) dysfunction remains challenging, but it is important to optimize therapies. The aim of this study was to determine the unbiased RNA profile in peripheral blood of patients with acute MI and to identify and validate new prognostic markers of LV dysfunction. METHODS: We prospectively enrolled a discovery cohort with acute MI (n=143) and performed whole-blood RNA profiling at different time points. We then selected transcripts on admission that related to LV dysfunction at follow-up and validated them by quantitative polymerase chain reaction in the discovery cohort, in an external validation cohort (n=449), and in a representative porcine MI model with cardiac magnetic resonance-based measurements of infarct size and postmortem myocardial pathology (n=33). RESULTS: RNA profiling in the discovery cohort showed upregulation of genes involved in chemotaxis, IL (interleukin)-6, and NF-κB (nuclear factor-κB) signaling in the acute phase of MI. Expression levels of the majority of these transcripts paralleled the rise in cardiac troponin T and decayed at 30 days. RNA levels of QSOX1, PLBD1, and S100A8 on admission with MI correlated with LV dysfunction at follow-up. Using quantitative polymerase chain reaction, we confirmed that QSOX1 and PLBD1 predicted LV dysfunction (odds ratio, 2.6 [95% CI, 1.1-6.1] and 3.2 [95% CI, 1.4-7.4]), whereas S100A8 did not. In the external validation cohort, we confirmed QSOX1 and PLBD1 as new independent markers of LV dysfunction (odds ratio, 1.41 [95% CI, 1.06-1.88] and 1.43 [95% CI, 1.08-1.89]). QSOX1 had an incremental predictive value in a model consisting of clinical variables and cardiac biomarkers (including NT-proBNP [N-terminal pro-B-type natriuretic peptide]). In the porcine MI model, whole-blood levels of QSOX1 and PLBD1 related to neutrophil infiltration in the ischemic myocardium in an infarct size-independent manner. CONCLUSIONS: Peripheral blood QSOX1 and PLBD1 in acute MI are new independent markers of LV dysfunction post-MI.

C-reactive protein during and after myocardial infarction in relation to cardiac injury and left ventricular function at follow-up.

BACKGROUND: Acute myocardial infarction (MI) invokes a large inflammatory response, which contributes to myocardial repair. HYPOTHESIS: We investigated whether C-reactive protein (CRP) measured during MI vs at 1 month follow-up improves the prediction of left ventricular (LV) function. METHODS: We prospectively enrolled 131 consecutive patients with acute MI and without non-cardiovascular causes of inflammation. We correlated admission and peak levels of CRP during hospitalization and high-sensitivity (hs) CRP at 1 month follow-up with markers of cardiac injury. Clinical follow-up and echocardiography for LV function were performed at a mean of 17 months. RESULTS: Median CRP levels were 1.89 mg/L on admission with MI, peaked to 12.10 mg/L during hospitalization and dropped to 1.24 mg/L at 1 month. Although admission CRP levels only weakly correlated with ejection fraction in the acute phase of MI (coefficient -0.164, P = 0.094), peak CRP was significantly related to ejection fraction (coefficient -0.4, P < 0.001), hsTroponin T (0.389, P < 0.001), and white blood cell count (0.389, P < 0.001). hsCRP at 1 month was not related to the extent of acute cardiac injury. These findings were replicated in an independent cohort of 57 patients. Peak CRP predicted LV dysfunction at follow-up (OR 11.0, 3.1-39.5 per log CRP, P < 0.001), persisting after adjustment for infarct size (OR 5.1, 1.1-23.6, P = 0.037), while hsCRP at 1 month was unrelated to LV function at follow-up. CONCLUSIONS: hsCRP 1 month post-MI does not relate to acute cardiac injury or LV function at follow-up, but we confirm that peak CRP is an independent predictor of LV dysfunction at follow-up.

Signal transduction analysis of the NLRP3-inflammasome pathway after cellular damage and its paracrine regulation.

Activation of the NLRP3-inflammasome pathway and production of the inflammatory cytokine IL-1B after cellular damage caused by infarct or infection is a key process in several diseases such as acute myocardial infarction and inflammatory bowel disease. However, while the molecular triggers of the NLRP3-pathway after cellular damage are well known, the mechanisms that sustain or confine its activity are currently under investigation. We present here an Ordinary Differential Equation-based model that investigates the mechanisms of inflammasome activation and regulation in monocytes to predict IL-1ß activation kinetics upon a two-step activation by Damage-Associate-Molecular-Particles (DAMP) and extracellular ATP. Assuming both activation signals to be concomitantly present or present with a delay of 12h, the model predicted a transient IL-1ß activation at different concentration levels dependent on signal synchronisation. Introducing a positive feedback loop mediated by active IL-1ß resulted in a sustained IL-1ß activation, hence arguing for a paracrine signalling between inflammatory cells to guarantee a temporally stable inflammatory response. We then investigate mechanisms that control termination of inflammation using two recently identified molecular intervention points in the inflammasome pathway. We found that a more upstream regulation, by attenuating production of the IL-1ß-proform, was more potent in attenuating active IL-1ß production than direct inhibition of the NLRP3-inflammasome. Interestingly, ablating this upstream negative feedback led to a high variability of IL-1ß production in monocytes from different subjects, consistent with a recent pre-clinical study. We finally discuss the relevance and implications of our findings in disease models of acute myocardial infarction and spontaneous colitis.