Neprilysin as a Biomarker: Challenges and Opportunities

Neprilysin (NEP) inhibition is a successful novel therapeutic approach in heart failure with reduced ejection fraction. Assessing individual NEP status might be important for gathering insights into mechanisms of disease and optimising individualised patient care. NEP is a zinc-dependent multisubstrate-metabolising oligoendopeptidase localised in the plasma membrane with the catalytic site facing the extracellular space. Although NEP activity in vivo is predominantly tissue-based, NEP can be released into the circulation via ectodomain shedding and exosomes. Attempts to determine circulating NEP concentrations and activity have not yet resulted in convincingly coherent results relating NEP biomarkers to heart failure disease severity or outcomes. NEP is naturally expressed on neutrophils, opening up the possibility of measuring a membrane-associated form with integrity. Small studies have linked NEP expression on neutrophils with inflammatory state and initial data might indicate its role in heart failure with reduced ejection fraction. Future studies need to assess the regulation of systemic NEP activity, which is assumed to be tissue-based, and the relationship of NEP activation with disease state. The relationship between tissue NEP activity and easily accessible circulating NEP biomarkers and the impact of the latter remains to be established

Cell-Based HIF1α Gene Therapy Reduces Myocardial Scar and Enhances Angiopoietic Proteome, Transcriptomic and miRNA Expression in Experimental Chronic Left Ventricular Dysfunction

Recent preclinical investigations and clinical trials with stem cells mostly studied bone-marrow-derived mononuclear cells (BM-MNCs), which so far failed to meet clinically significant functional study endpoints. BM-MNCs containing small proportions of stem cells provide little regenerative potential, while mesenchymal stem cells (MSCs) promise effective therapy via paracrine impact. Genetic engineering for rationally enhancing paracrine effects of implanted stem cells is an attractive option for further development of therapeutic cardiac repair strategies. Non-viral, efficient transfection methods promise improved clinical translation, longevity and a high level of gene delivery. Hypoxia-induced factor 1α is responsible for pro-angiogenic, anti-apoptotic and anti-remodeling mechanisms. Here we aimed to apply a cellular gene therapy model in chronic ischemic heart failure in pigs. A non-viral circular minicircle DNA vector (MiCi) was used for in vitro transfection of porcine MSCs (pMSC) with HIF1α (pMSC-MiCi-HIF-1α). pMSCs-MiCi-HIF-1α were injected endomyocardially into the border zone of an anterior myocardial infarction one month post-reperfused-infarct. Cell injection was guided via 3D-guided NOGA electro-magnetic catheter delivery system. pMSC-MiCi-HIF-1α delivery improved cardiac output and reduced myocardial scar size. Abundances of pro-angiogenic proteins were analyzed 12, 24 h and 1 month after the delivery of the regenerative substances. In a protein array, the significantly increased angiogenesis proteins were Activin A, Angiopoietin, Artemin, Endothelin-1, MCP-1; and remodeling factors ADAMTS1, FGFs, TGFb1, MMPs, and Serpins. In a qPCR analysis, increased levels of angiopeptin, CXCL12, HIF-1α and miR-132 were found 24 h after cell-based gene delivery, compared to those in untreated animals with infarction and in control animals. Expression of angiopeptin increased already 12 h after treatment, and miR-1 expression was reduced at that time point. In total, pMSC overexpressing HIF-1α showed beneficial effects for treatment of ischemic injury, mediated by stimulation of angiogenesis

Short structured feedback training is equivalent to a mechanical feedback device in two-rescuer BLS: a randomised simulation study.

BACKGROUND Resuscitation guidelines encourage the use of cardiopulmonary resuscitation (CPR) feedback devices implying better outcomes after sudden cardiac arrest. Whether effective continuous feedback could also be given verbally by a second rescuer ("human feedback") has not been investigated yet. We, therefore, compared the effect of human feedback to a CPR feedback device. METHODS In an open, prospective, randomised, controlled trial, we compared CPR performance of three groups of medical students in a two-rescuer scenario. Group "sCPR" was taught standard BLS without continuous feedback, serving as control. Group "mfCPR" was taught BLS with mechanical audio-visual feedback (HeartStart MRx with Q-CPR-Technology™). Group "hfCPR" was taught standard BLS with human feedback. Afterwards, 326 medical students performed two-rescuer BLS on a manikin for 8 min. CPR quality parameters, such as "effective compression ratio" (ECR: compressions with correct hand position, depth and complete decompression multiplied by flow-time fraction), and other compression, ventilation and time-related parameters were assessed for all groups. RESULTS ECR was comparable between the hfCPR and the mfCPR group (0.33 vs. 0.35, p = 0.435). The hfCPR group needed less time until starting chest compressions (2 vs. 8 s, p < 0.001) and showed fewer incorrect decompressions (26 vs. 33 %, p = 0.044). On the other hand, absolute hands-off time was higher in the hfCPR group (67 vs. 60 s, p = 0.021). CONCLUSIONS The quality of CPR with human feedback or by using a mechanical audio-visual feedback device was similar. Further studies should investigate whether extended human feedback training could further increase CPR quality at comparable costs for training

Effect of Ischemic Preconditioning and Postconditioning on Exosome-Rich Fraction microRNA Levels, in Relation with Electrophysiological Parameters and Ventricular Arrhythmia in Experimental Closed-Chest Reperfused Myocardial Infarction

We investigated the antiarrhythmic effects of ischemic preconditioning (IPC) and postconditioning (PostC) by intracardiac electrocardiogram (ECG) and measured circulating microRNAs (miRs) that are related to cardiac conduction. Domestic pigs underwent 90-min. percutaneous occlusion of the mid left anterior coronary artery, followed by reperfusion. The animals were divided into three groups: acute myocardial infarction (AMI, n = 7), ischemic preconditioning-acute myocardial infarction (IPC-AMI) (n = 9), or AMI-PostC (n = 5). IPC was induced by three 5-min. episodes of repetitive ischemia/reperfusion cycles (rI/R) before AMI. PostC was induced by six 30-s rI/R immediately after induction of reperfusion 90 min after occlusion. Before the angiographic procedure, a NOGA endocardial mapping catheter was placed again the distal anterior ventricular endocardium to record the intracardiac electrogram (R-amplitude, ST-Elevation, ST-area under the curve (AUC), QRS width, and corrected QT time (QTc)) during the entire procedure. An arrhythmia score was calculated. Cardiac MRI was performed after one-month. IPC led to significantly lower ST-elevation, heart rate, and arrhythmia score during ischemia. PostC induced a rapid recovery of R-amplitude, decrease in QTc, and lower arrhythmia score during reperfusion. Slightly higher levels of miR-26 and miR-133 were observed in AMI compared to groups IPC-AMI and AMI-PostC. Significantly lower levels of miR-1, miR-208, and miR-328 were measured in the AMI-PostC group as compared to animals in group AMI and IPC-AMI. The arrhythmia score was not significantly associated with miRNA plasma levels. Cardiac MRI showed significantly smaller infarct size in the IPC-AMI group when compared to the AMI and AMI-PostC groups. Thus, IPC led to better left ventricular ejection fraction at one-month and it exerted antiarrhythmic effects during ischemia, whereas PostC exhibited antiarrhythmic properties after reperfusion, with significant downregulaton of ischemia-related miRNAs

Transcriptional Alterations by Ischaemic Postconditioning in a Pig Infarction Model: Impact on Microvascular Protection

Although the application of cardioprotective ischaemia/reperfusion (I/R) stimuli after myocardial infarction (MI) is a promising concept for salvaging the myocardium, translation to a clinical scenario has not fulfilled expectations. We have previously shown that in pigs, ischaemic postconditioning (IPostC) reduces myocardial oedema and microvascular obstruction (MVO), without influencing myocardial infarct size. In the present study, we analyzed the mechanisms underlying the IPostC-induced microvascular protection by transcriptomic analysis, followed by pathway analysis. Closed-chest reperfused MI was induced by 90 min percutaneous balloon occlusion of the left anterior descending coronary artery, followed by balloon deflation in anaesthetised pigs. Animals were randomised to IPostC (n = 8), MI (non-conditioned, n = 8), or Control (sham-operated, n = 4) groups. After three hours or three days follow-up, myocardial tissue samples were harvested and subjected to RNA-seq analysis. Although the transcriptome analysis revealed similar expression between IPostC and MI in transcripts involved in cardioprotective pathways, we identified gene expression changes responding to IPostC at the three days follow-up. Focal adhesion signaling, downregulated genes participating in cardiomyopathy and activation of blood cells may have critical consequences for microvascular protection. Specific analyses of the gene subsets enriched in the endothelium of the infarcted area, revealed strong deregulation of transcriptional functional clusters, DNA processing, replication and repair, cell proliferation, and focal adhesion, suggesting sustentative function in the endothelial cell layer protection and integrity. The spatial and time-dependent transcriptome analysis of porcine myocardium supports a protective effect of IPostC on coronary microvasculature post-MI

Cardiac regeneration in ischaemic cardiomyopathy : cell-free cardiac regeneration in ischaemic cardiomyopathy: The paracrine regenerative effect of the secretome of apoptotic pripheral blood mononuclear cells (APOSEC)

In den letzten Jahren traten in der Regenerationsmedizin parakrine Effekte von ins Myokard transplantierten Zellen in den Vordergrund, da diese als wahrscheinlichste Erklärung für den kardioregenerativen Effekt einer Zelltherapie gelten. Unsere Gruppe konnte in früheren Untersuchungen zeigen, dass im Großtiermodell die intravenöse Verabreichung des Sekretoms von apoptotischen PBMC (APOSEC) im akuten Myokardinfarkt die Infarktgröße reduzieren und die linksventrikuläre Auswurfsfraktion erhöhen kann. Die primäre Fragestellung dieser Arbeit war es 1. Beweise für den regenerativen Effekt von APOSEC in einem translationalen Model der chronischen linkventrikulären Dysfunktion zu gewinnen; 2. den kardioprotektiven Effekt von APOSEC auf Ebene der Genexpression zu untersuchen; und 3. die diagnostische Qualität des sogenannten perkutanen intramyokardialen Navigationssystems (NOGA) durch Vergleich mit der kardialen Magnetresonanzuntersuchung mit late enhancement (MRT-LE) nach myokardialer Ischämie zu quantifizieren. Wir konnten zeigen, das die Injektion von APOSEC verglichen mit Kontrollen im chronischen Modell die Infarktgröße signifikant reduzieren sowie den cardiac Index und myokardiale Viabilität signifikant erhöhen konnte. Die Analyse des Transkriptoms zeigte eine signifikante Downregulation von apoptotischen und pro-inflammatorischen Molekülen in den mit APOSEC behandelten Myokardregionen. Die RT-PCR-Untersuchung ergab eine höhere Expression von Mef2c und eine niedrigere von Caspase-1 in APOSEC behandelten Tieren. Die veränderte Genexpression auch nach einem Monat beweist den langanhaltenden Effekt einer zell-freien Therapie mit parakrinen Faktoren. Beim Vergleich der diagnostischen Qualität des NOGA endokardialen Mappings mit den Ergebnissen des MRT-LE konnten wir zeigen, dass sich NOGA durch Kombination von unipolaren und bipolaren Maps als nützliches und genaues Werkzeug erwies um die Zielzone für eine intramyokardiale Therapie richtig zu identifizieren.In the last years the paracrine factors of myocardial transplanted cells were discussed to represent the likeliest mechanism underlying cardiac regeneration. Previously, our group showed that intravenous administration of the secrteome of apoptotoc peripheral blood mononuclear cells (APOSEC) was effective in reducing infarction size and increasing left ventricular ejection fraction. The primary aims of this doctoral thesis were to (1) evaluate the regenerative effect of APOSEC in a translational model of chronic ischemic left ventricular (LV) dysfunction; (2) explore the cardioprotective effect of APOSEC using gene expression analysis in ischaemic cardiomyopathy (iCMP); and (3) validate the diagnostic value of a percutaneous intramyocardial navigation system that has been used for cell-based regeneration in iCMP, comparing it to a magnetic resonance imaging (MRI) approach (cardiac MRI; cMRI) with late enhancement (cMRI-LE). In the chronic model, APOSEC injection was associated with a decrease in infarct size, improved cardiac index, and improved myocardial viability compared to controls. We found that in areas exposed to APOSEC, apoptotic and inflammation-related genes were downregulated. RT-PCR confirmed downregulation of Caspase-1 and showed upreglutaion of Mef2c in APOSEC-treated animals. Genexpression changes 30 days after treatment demonstrate long-lasting effects of this cell-free paracrine factor therapy. Moreover, by combining unipolar with bipolar voltage maps of NOGA, the endocardial mapping was comparable to cMRI-LE for accurately characterizing the zone of interest for intramyocardial therapy. Thus we have demonstrated that cell-free therapy targeting regeneration for chronic ischemic LV dysfunction can be efficacious when applied intramyocardially via percutaneous injection by NOGA.submitted by Noemi PavoMedizinische Universität Wien, Dissertation, 2016OeB

Parameters associated with therapeutic response using peritoneal dialysis for therapy refractory heart failure and congestive right ventricular dysfunction.

BACKGROUND:In patients with refractory heart failure (HF) peritoneal dialysis (PD) is associated with improved functional status and decrease in hospitalization. However, previous studies did not focus on right ventricular dysfunction as an important pathophysiologic component of cardiorenal syndrome. METHODS:In a prospective cohort study PD was started in 40 patients with refractory right HF (with/without left HF). Refractoriness to conservative therapy was defined as persistent right heart congestion/ascites with intensified diuretic treatment and/or ≥2 hospitalizations within 6 months because of cardiac decompensation despite optimal medical treatment, and/or acute renal failure during intensified conservative treatment of cardiac decompensations. RESULTS:Patient survival was 55.0% at 1 year, 35.0% at 2 years and 27.5% at 3 years. The number of hospitalization days declined after initiation of PD for both cardiac [13 (IQR 1-53) days before vs. 1 (IQR 0-12) days after start of PD, p<0.001] and unplanned reasons [12 (IQR 3-44) days before vs. 1 (IQR 0-33) days after start of PD, p = 0.007]. Using a combined endpoint including survival time of ≥1 year and either improvement in quality of life or decline in hospitalizations we found that patients with extended ascites, higher systolic pulmonary artery pressure, more marked impairment of right ventricular function and tricuspid valve insufficiency, higher residual renal function as well as those who could perform PD without assistance have benefited most from this therapy. CONCLUSIONS:Patients with more pronounced backward failure, less marked residual renal functional impairment and those not depending on assistance for therapy are likely to profit most from PD

The inflammation‐based modified Glasgow prognostic score is associated with survival in stable heart failure patients

Abstract Aims The progression of heart failure is presumably dependent on the individual inflammatory host response. The combination of the inflammatory markers, albumin, and C‐reactive protein, termed modified Glasgow prognostic score (mGPS), has been derived from cancer patients and validated in multiple cohorts. This study aimed to investigate the impact of the easily available mGPS on survival of stable patients with heart failure with reduced ejection fraction (HFrEF). Methods and results Patients with stable HFrEF undergoing routine ambulatory care between January 2011 and November 2017 have been identified from a prospective registry at the Medical University of Vienna. Comorbidities, laboratory data as well as the nutritional risk index at baseline were assessed. All‐cause mortality was defined as the primary study end point. The mGPS was calculated, and its association with heart failure severity and impact on overall survival were determined. Data were analysed for a total of 443 patients. The mGPS was 0 for 352 (80%), 1 for 76 (17%), and 2 for 14 (3%) patients, respectively. Elevation of mGPS was associated with worsening of routine laboratory parameters linked to prognosis, especially NT‐proBNP [median 1830 pg/mL (IQR 764–3455) vs. 4484 pg/mL (IQR 1565–8003) vs. 6343 pg/mL (IQR 3750–15401) for mGPS 0, 1, and 2, respectively; P < 0.001] and nutritional risk index. In the Cox regression analysis, the increase of mGPS was associated with adverse outcome in the univariate analysis [crude hazard ratio 3.00 (95% CI 2.14–4.21), P < 0.001] and after adjustment for multiple covariates as age, gender, body mass index, and glomerular filtration rate as well as heart failure severity reflected by NT‐proBNP and New York Heart Association class [adj. hazard ratio 1.87 (95% CI 1.19–2.93), P = 0.006]. Conclusions Enhanced inflammation and nutritional depletion are more common in advanced heart failure. The inflammation‐based score mGPS predicts survival in HFrEF patients independently of NT‐proBNP emphasizing the significance of the individual pro‐inflammatory response on prognosis