Minute Myocardial Injury as Measured by High-Sensitive Troponin T Serum Levels Predicts the Response to Intracoronary Infusion of Bone Marrow-Derived Mononuclear Cells in Patients With Stable Chronic Post-Infarction Heart Failure: Insights From the TOPCARE-CHD Registry

Non-Coding RNAs in Stem Cell Regulation and Cardiac Regeneration: Current Problems and Future Perspectives

Although advances in rapid revascularization strategies following acute myocardial infarction (AMI) have led to improved short and long-term outcomes, the associated loss of cardiomyocytes and the subsequent remodeling result in an impaired ventricular function that can lead to heart failure or death. The poor regenerative capacity of the myocardium and the current lack of effective regenerative therapies have driven stem cell research in search of a possible solution. One approach involves the delivery of stem cells to the site of injury in order to stimulate repair response. Although animal studies initially delivered promising results, the application of similar techniques in humans has been hampered by poor target site retention and oncogenic considerations. In response, several alternative strategies, including the use of non-coding RNAs (ncRNAs), have been introduced with the aim of activating and regulating stem cells or inducing stem cell status in resident cells. Circular RNAs (circRNAs) and microRNAs (miRNAs) are ncRNAs with pivotal functions in cell proliferation and differentiation, whose role in stem cell regulation and potential significance for the field of cardiac regeneration is the primary focus of this review. We also address the general advantages of ncRNAs as promising drivers of cardiac regeneration and potent stem cell regulators.

The prognostic role of high-sensitivity cardiac troponin T over time in ischemic and non-ischemic heart failure

INTRODUCTION

High-sensitivity cardiac troponin T (hs-cTnT) as a prognostic biomarker can be detected in patients with heart failure (HF).

AIM

This study focuses on hs-cTnT to evaluate its prognostic role in ischemic heart failure (IHF) and non-ischemic heart failure (NIHF).

MATERIAL AND METHODS

One hundred and sixty patients with HF were divided into IHF and NIHF groups. Hs-cTnT measured at baseline, 2-5 h, 6-24 h and 24 h-7 d after admission was analyzed by generalized estimating equations. Patients were followed up for 1 year at the endpoint events of re-hospitalization for HF and all-cause death that was tested by the Kaplan-Meier method and the Cox regression method.

RESULTS

Hs-cTnT varied significantly over time, first increasing and then decreasing in IHF while showing a continuously elevated trend in NIHF. Patients with hs-cTnT levels > 0.014 ng/ml had a significantly higher re-hospitalization rate compared with those with hs-cTnT levels ≤ 0.014 ng/ml (23.7% vs. 7.0%, p < 0.05). Adjusted for age, New York Heart Association class, N-terminal pro-B-type natriuretic peptide, and left ventricular ejection fraction, baseline hs-cTnT was independently associated with re-hospitalization and all-cause death in HF (p < 0.05). Optimal hs-cTnT cut-off of 0.0275 ng/ml was derived to predict the re-hospitalization and death in IHF (AUC = 0.709, 95% CI: 0.561-0.856, sensitivity: 76.9%, specificity: 63.5%, p < 0.05).

CONCLUSIONS

Hs-cTnT varying over time is an important risk factor for the prognosis of patients with IHF and NIHF.

Correlation of Serum Cardiac Markers with Acute Decompensating Events in Liver Cirrhosis

METHODS

Cirrhotic patients who were consecutively hospitalized between January 2016 and March 2019 were screened. Serum cardiac biomarkers at admission, including N-Terminal pro-B-type natriuretic peptide (NT-pro BNP), high-sensitivity cardiac troponin T (hs-cTnT), creatine kinase (CK), creatine kinase MB (CK-MB), and lactate dehydrogenase (LDH), were collected. Acute decompensating events at admission, primarily including ascites, acute gastrointestinal hemorrhage, and acute-on-chronic liver failure (ACLF), were recorded.

RESULTS

The NT-pro BNP level was significantly higher in cirrhotic patients with acute decompensating events than in those without any decompensating events (median: 140.75 pg/mL versus 41.86 pg/mL, P < 0.001). The NT-pro BNP level significantly correlated with ascites, acute gastrointestinal hemorrhage, and ACLF. The hs-cTnT level was significantly higher in cirrhotic patients with acute decompensating events than in those without decompensating events (median: 0.008 ng/mL versus 0.006 ng/mL, P = 0.007). The hs-cTnT level significantly correlated with acute gastrointestinal hemorrhage, but not ascites or ACLF. LDH (185.0 U/L versus 173.5 U/L, P = 0.281), CK (71 U/L versus 84 U/L, P = 0.157), and CK-MB (29.5 U/L versus 33.0 U/L, P = 0.604) levels were not significantly different between cirrhotic patients with and without acute decompensating events.

CONCLUSION

The elevated NT-pro BNP level seems to be closely related to the development of acute decompensating events in liver cirrhosis.

Clinical-based Cell Therapies for Heart Disease-Current and Future State

Patients have an ongoing unmet need for effective therapies that reverse the cellular and functional damage associated with heart damage and disease. The discovery that ~1%-2% of adult cardiomyocytes turn over per year provided the impetus for treatments that stimulate endogenous repair mechanisms that augment this rate. Preclinical and clinical studies provide evidence that cell-based therapy meets these therapeutic criteria. Recent and ongoing studies are focused on determining which cell type(s) works best for specific patient population(s) and the mechanism(s) by which these cells promote repair. Here we review clinical and preclinical stem cell studies and anticipate future directions of regenerative medicine for heart disease.

Pursuing meaningful end-points for stem cell therapy assessment in ischemic cardiac disease

Despite optimal interventional and medical therapy, ischemic heart disease is still an important cause of morbidity and mortality worldwide. Although not included in standard of care rehabilitation, stem cell therapy (SCT) could be a solution for prompting cardiac regeneration. Multiple studies have been published from the beginning of SCT until now, but overall no unanimous conclusion could be drawn in part due to the lack of appropriate end-points. In order to appreciate the impact of SCT, multiple markers from different categories should be considered: Structural, biological, functional, physiological, but also major adverse cardiac events or quality of life. Imaging end-points are among the most used - especially left ventricle ejection fraction (LVEF) measured through different methods. Other imaging parameters are infarct size, myocardial viability and perfusion. The impact of SCT on all of the aforementioned end-points is controversial and debatable. 2D-echocardiography is widely exploited, but new approaches such as tissue Doppler, strain/strain rate or 3D-echocardiography are more accurate, especially since the latter one is comparable with the MRI gold standard estimation of LVEF. Apart from the objective parameters, there are also patient-centered evaluations to reveal the benefits of SCT, such as quality of life and performance status, the most valuable from the patient point of view. Emerging parameters investigating molecular pathways such as non-coding RNAs or inflammation cytokines have a high potential as prognostic factors. Due to the disadvantages of current techniques, new imaging methods with labelled cells tracked along their lifetime seem promising, but until now only pre-clinical trials have been conducted in humans. Overall, SCT is characterized by high heterogeneity not only in preparation, administration and type of cells, but also in quantification of therapy effects.

Mitoprotection attenuates myocardial vascular impairment in porcine metabolic syndrome

Metabolic syndrome (MetS) leads to cardiac vascular injury, which may reflect in increased retention of endothelial progenitor cells (EPCs). Coronary endothelial cell (EC) mitochondria partly regulate vascular function and structure. We hypothesized that chronic mitoprotection would preserve EC mitochondria and attenuate coronary vascular injury and dysfunction in swine MetS. Pigs were studied after 16 wk of diet-induced MetS, MetS treated for the last 4 wk with the mitochondria-targeted peptide elamipretide (ELAM; 0.1 mg/kg sc once daily), and lean controls ( n = 6 each). Cardiac remodeling and function were assessed in vivo by multidetector-computed tomography (CT), and coronary artery and sinus blood samples were collected. EC mitochondrial density, apoptosis, oxidative stress, endothelial nitric oxide synthase immunoreactivity, myocardial microvascular density (three-dimensional microcomputed tomography), and coronary endothelial function (organ bath) were assessed ex vivo. The number and arteriovenous gradient of CD34⁺/KDR⁺ EPCs were calculated by FACS (a negative net gradient indicating EPC retention). MetS and MetS + ELAM pigs developed similar MetS (obesity, hyperlipidemia, insulin resistance, and hypertension). EC mitochondrial density decreased in MetS animals compared with lean animals but normalized in MetS + ELAM animals. ELAM also attenuated EC oxidative stress and apoptosis and improved subendocardial microvascular density. ELAM-induced vasculoprotection was reflected by decreased coronary retention of EPCs. ELAM also partly improved endothelial nitric oxide synthase immunoreactivity, coronary endothelial function, and vessel maturity, whereas myocardial perfusion was unaffected. Chronic mitoprotection improved coronary EC mitochondrial density and decreased vascular remodeling and dysfunction. However, additional mitochondria-independent mechanisms likely contribute to MetS-induced cardiac vascular injury. NEW & NOTEWORTHY The present study shows that chronic mitoprotection preserved coronary endothelial cell mitochondria and decreased vascular injury, subendocardial microvascular loss, coronary retention of endothelial progenitor cells, and release of markers of vascular injury. However, myocardial perfusion remained blunted, suggesting that additional mitochondria-independent mechanisms likely contribute to metabolic syndrome-induced cardiac vascular injury.