Bone marrow mesenchymal stem cells protected post-infarcted myocardium against arrhythmias via reversing potassium channels remodelling

The Application of Mesenchymal Stem Cells in Different Cardiovascular Disorders: Ways of Administration, and the Effectors

The heart is an organ with a low ability to renew and repair itself. MSCs have cell surface markers such as CD45-, CD34-, CD31-, CD4+, CD11a+, CD11b+, CD15+, CD18+, CD25+, CD49d+, CD50+, CD105+, CD73+, CD90+, CD9+, CD10+, CD106+, CD109+, CD127+, CD120a+, CD120b+, CD124+, CD126+, CD140a+, CD140b+, adherent properties and the ability to differentiate into cells such as adipocytes, osteoblasts and chondrocytes. Autogenic, allogeneic, normal, pretreated and genetically modified MSCs and secretomes are used in preclinical and clinical studies. MSCs and their secretomes (the total released molecules) generally have cardioprotective effects. Studies on cardiovascular diseases using MSCs and their secretomes include myocardial infraction/ischemia, fibrosis, hypertrophy, dilated cardiomyopathy and atherosclerosis. Stem cells or their secretomes used for this purpose are administered to the heart via intracoronary (Antegrade intracoronary and retrograde coronary venous injection), intramyocardial (Transendocardial and epicardial injection) and intravenous routes. The protective effects of MSCs and their secretomes on the heart are generally attributed to their differentiation into cardiomyocytes and endothelial cells, their immunomodulatory properties, paracrine effects, increasing blood vessel density, cardiac remodeling, and ejection fraction and decreasing apoptosis, the size of the wound, end-diastolic volume, end-systolic volume, ventricular myo-mass, fibrosis, matrix metalloproteins, and oxidative stress. The present review aims to assist researchers and physicians in selecting the appropriate cell type, secretomes, and technique to increase the chance of success in designing therapeutic strategies against cardiovascular diseases.

Electrophysiological effects of adipose graft transposition procedure (AGTP) on the post-myocardial infarction scar: A multimodal characterization of arrhythmogenic substrate

Objective

To assess the arrhythmic safety profile of the adipose graft transposition procedure (AGTP) and its electrophysiological effects on post-myocardial infarction (MI) scar.

Background

Myocardial repair is a promising treatment for patients with MI. The AGTP is a cardiac reparative therapy that reduces infarct size and improves cardiac function. The impact of AGTP on arrhythmogenesis has not been addressed.

Methods

MI was induced in 20 swine. Contrast-enhanced magnetic resonance (ce-MRI), electrophysiological study (EPS), and left-ventricular endocardial high-density mapping were performed 15 days post-MI. Animals were randomized 1:1 to AGTP or sham-surgery group and monitored with ECG-Holter. Repeat EPS, endocardial mapping, and ce-MRI were performed 30 days post-intervention. Myocardial SERCA2, Connexin-43 (Cx43), Ryanodine receptor-2 (RyR2), and cardiac troponin-I (cTnI) gene and protein expression were evaluated.

Results

The AGTP group showed a significant reduction of the total infarct scar, border zone and dense scar mass by ce-MRI (p = 0.04), and a decreased total scar and border zone area in bipolar voltage mapping (p < 0.001). AGTP treatment significantly reduced the area of very-slow conduction velocity (<0.2 m/s) (p = 0.002), the number of deceleration zones (p = 0.029), and the area of fractionated electrograms (p = 0.005). No differences were detected in number of induced or spontaneous ventricular arrhythmias at EPS and Holter-monitoring. SERCA2, Cx43, and RyR2 gene expression were decreased in the infarct core of AGTP-treated animals (p = 0.021, p = 0.018, p = 0.051, respectively).

Conclusion

AGTP is a safe reparative therapy in terms of arrhythmic risk and provides additional protective effect against adverse electrophysiological remodeling in ischemic heart disease.

Increased Myocardial Retention of Mesenchymal Stem Cells Post-MI by Pre-Conditioning Exercise Training

Stem cell (SC) therapy is a promising approach to improve post-myocardial infarction (MI) cardiac remodeling, but the proinflammatory microenvironment may lead to SC loss and, therefore, may have a negative impact on therapy. It appears that exercise training (ET) improves myocardial microenvironment for SC transplantation. Therefore, we tested the effect of ET on post-infarction retention of adipose-derived SCs (ADSCs) and its combined effects on the inflammatory microenvironment. Fischer-344 female rats were randomized to one of the following groups: Sham; sedentary coronary occlusion who did not receive ADSCs (sMI); sedentary coronary occlusion who received ADSCs; exercise coronary occlusion who received ADSCs. Rats were trained nine weeks prior to MI, followed by ADSCs transplantation. The MI led to left ventricle (LV) dilation and dysfunction, myocardial hypertrophy and fibrosis, and increased proinflammatory profile compared to Sham rats. Conversely, ADSCs transplanted rats exhibited, better morphological and functional LV parameters; inhibition of myocardial hypertrophy and fibrosis; and attenuation of proinflammatory cytokines (interleukins 1β and 10, tumor necrosis factor α, and transforming growth factor β) in the myocardium compared to sMI rats. Interestingly, ET enhanced the effect of ADSCs on interleukin 10 expression. There was a correlation between cytokine expression and myocardial ADSCs retention. The. ET enhanced the beneficial effects of ADSCs in infarcted myocardium, which was associated with higher ADSCs retention. These findings highlight the importance of ET in myocardial retention of ADSCs and attenuation of cardiac remodeling post-infarction. Cytokine analysis suggests improvement in ET-linked myocardial microenvironment based on its anti-inflammatory action.

The Role of MSC Therapy in Attenuating the Damaging Effects of the Cytokine Storm Induced by COVID-19 on the Heart and Cardiovascular System

The global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19) has led to 47 m infected cases and 1. 2 m (2.6%) deaths. A hallmark of more severe cases of SARS-CoV-2 in patients with acute respiratory distress syndrome (ARDS) appears to be a virally-induced over-activation or unregulated response of the immune system, termed a "cytokine storm," featuring elevated levels of pro-inflammatory cytokines such as IL-2, IL-6, IL-7, IL-22, CXCL10, and TNFα. Whilst the lungs are the primary site of infection for SARS-CoV-2, in more severe cases its effects can be detected in multiple organ systems. Indeed, many COVID-19 positive patients develop cardiovascular complications, such as myocardial injury, myocarditis, cardiac arrhythmia, and thromboembolism, which are associated with higher mortality. Drug and cell therapies targeting immunosuppression have been suggested to help combat the cytokine storm. In particular, mesenchymal stromal cells (MSCs), owing to their powerful immunomodulatory ability, have shown promise in early clinical studies to avoid, prevent or attenuate the cytokine storm. In this review, we will discuss the mechanistic underpinnings of the cytokine storm on the cardiovascular system, and how MSCs potentially attenuate the damage caused by the cytokine storm induced by COVID-19. We will also address how MSC transplantation could alleviate the long-term complications seen in some COVID-19 patients, such as improving tissue repair and regeneration.

Antioxidant and Cytoprotective effects of Pyrola decorata H. Andres and its five phenolic components

Background

Pyrola decorata H. Andres, is exclusively distributed in China and a source of traditional Chinese herbal medicine Luxiancao for more than 2000 years. Here, we evaluated the antioxidant and cytoprotective effects of P. decorata and its five phenolic components (protocatechuic acid, gallic acid, hyperoside, 2′′-O-galloylhyperin, and quercetin), and discussed their antioxidant chemistry.

Methods

A lyophilized aqueous extract of P. decorata (LAEP) was prepared and analyzed with high-performance liquid chromatography (HPLC). LAEP and its five phenolic components were comparatively investigated using five antioxidant assays, including ferric-reducing antioxidant power, cupric ion-reducing antioxidant capacity, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide radical (PTIO^•)-scavenging, 1,1-diphenyl-2-picryl-hydrazl radical (DPPH^•)-scavenging, and 2,2′-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) radical (ABTS^+•)-scavenging activities. The reaction products of the five phenolic components with 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl radical (4-methoxy-TEMPO^•) were determined with ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) analysis. LAEP and its five phenolic components were incubated with bone marrow-derived mesenchymal stem cells (bmMSCs) subjected to oxidative stress to demonstrate their cytoprotective effects with a flow cytometry assay.

Results

In the five antioxidant assays, LAEP and its five phenolic components dose-dependently increased the radical-scavenging (or reducing power) activities. However, the IC₅₀ values of hyperoside were consistently higher than those of 2′′-O-galloylhyperin. UPLC-ESI-Q-TOF-MS/MS analysis results indicated that the five phenolics could yield dimer products in the presence of 4-methoxy-TEMPO^• via the radical adduct formation (RAF) pathway. Flow cytometry assay results confirmed the cytoprotective activity of LAEP and its five phenolic components toward stressed bmMSCs. In particular, 2′′-O-galloylhyperin could more effectively reduce the percentage of damaged bmMSCs than hyperoside.

Conclusion

LAEP and its five phenolic components may undergo redox-based pathways (such as electron transfer and H⁺ transfer) and covalent-based pathway (i.e., RAF) to exhibit antioxidant activity. One consequence of RAF is the generation of phenolic-phenolic dimer. In both organic and aqueous media, 2′′-O-galloylhyperin exhibited higher redox-based antioxidant levels (or cytoprotective levels) than those with hyperoside. The differences could be attributed to 2′′-O-galloylation reaction.

Low-level laser therapy alleviates the deleterious effect of doxorubicin on rat adipose tissue-derived mesenchymal stem cells

Cancer is a leading cause of death worldwide, and doxorubicin (DOX) has become one of the most commonly prescribed drugs. Stem cell (SC) therapy is proving to be a promising strategy to alleviate DOX adverse effects on non-cancerous cells. However, the drug also has a toxic action on SCs, reducing the efficiency of cell therapy from a preventive view. The present study shows that the DOX toxicity in mesenchymal SCs (MSCs) can be partially overcome by low-level laser irradiation (LLLI). To achieve this, we applied the low-level red laser (wavelength: 660 nm; output power: 30 mW; laser beam: 0.028 cm²; irradiation: 1.07 mW/cm²; Ga-Al-As Photon Laser III, DMC, São Paulo, Brazil) in rat adipose tissue-derived MSCs before their exposure to different DOX concentrations. Results revealed that the DOX reduced the viability and adenosine triphosphate level of MSCs. These findings were followed by significantly increased apoptosis as well as oxidative stress in the MSCs. Interestingly, LLLI at the dose of 0.2 J alleviated the effects of DOX on cell viability and apoptosis, and inhibited oxidative stress in the MSCs. In summary, this study provides a crucial step toward the future application of LLLI as a protective approach against DOX-induced toxicity in MSCs, particularly cell death. This study also lays the groundwork for further investigation into the role of oxidative stress and inflammation as an instructive milieu for cell protection.

Yixin-Shu facilitated cardiac-like differentiation of mesenchymal stem cells in vitro

Yixin-Shu capsules (YXS) are a Chinese Materia Medica standardized product used for heart disease and their effectiveness has been demonstrated through both clinical and experimental research. However, the mechanism involved has remained unclear. The effect of YXS on the cardiac-like differentiation of mesenchymal stem cells was investigated in this study. The intestinal absorption liquid of YXS was prepared using an in vitro intestinal absorption method and 62 compounds have been identified. A compound-target-function network constructed by a network pharmacology-based approach indicated that these compounds had an effect on cell differentiation. The effects of YXS on cardiac-like differentiation of mesenchymal stem cells was verified by detecting cardiac-specific protein expression such as α-actinin, cardiac troponin-I and desmin through real time-PCR, western blotting and immunofluorescence staining. A network pharmacology analysis indicated that the facilitation of YXS on the cardiac-like differentiation may be through the TGF-β signaling pathway, Wnt signaling pathway and MAPK signaling pathway. The observed improvements on cardiac differentiation may be due to the novel molecular mechanism for YXS that could also benefit developments in cardiac tissue engineering.

Ventricular Arrhythmia after Acute Myocardial Infarction: 'The Perfect Storm'

Ventricular tachyarrhythmias (VAs) commonly occur early in ischaemia, and remain a common cause of sudden death in acute MI. The thrombolysis and primary percutaneous coronary intervention era has resulted in the modification of the natural history of an infarct and subsequent VA. Presence of VA could independently influence mortality in patients recovering from MI. Appropriate risk assessment and subsequent treatment is warranted in these patients. The prevention and treatment of haemodynamically significant VA in the post-infarct period and of sudden cardiac death remote from the event remain areas of ongoing study.

Mesenchymal stem cells suppress cardiac alternans by activation of PI3K mediated nitroso-redox pathway

BACKGROUND

The paracrine action of non-cardiac progenitor cells is robust, but not well understood. Mesenchymal stem cells (MSC) have been shown to enhance calcium (Ca(++)) cycling in myocytes. Therefore, we hypothesized that MSCs can suppress cardiac alternans, an important arrhythmia substrate, by paracrine action on Ca(++) cycling.

METHODS AND RESULTS

Human cardiac myocyte monolayers derived from iPS cells (hCM) were cultured without or with human MSCs (hMSC) directly or plated on a transwell insert. Ca(++) transient alternans (Ca(++) ALT) and Ca(++) transient duration (CaD) were measured from hCM monolayers following application of 200μM H2O2. Ca(++) ALT in hCM was significantly decreased when cultured with hMSCs directly (97%, p<0.0001) and when cultured with hMSC in the transwell insert (80%, p<0.0001). When hCM with hMSCs were pretreated with PI3K or eNOS inhibitors, Ca(++) ALT was larger than baseline by 20% (p<0.0001) and 36% (p<0.0001), respectively. In contrast, Ca(++) ALT was reduced by 89% compared to baseline (p<0.0001) when hCM monolayers without hMSCs were pretreated with 20μM GSNO. In all experiments, changes in Ca(++) ALT were mirrored by changes in CaD. Finally, real time quantitative PCR revealed no significant differences in mRNA expression of RyR2, SERCA2a, and phospholamban between hCM cultured with or without hMSCs.

CONCLUSION

Ca(++) ALT is suppressed by hMSCs in a paracrine fashion due to activation of a PI3K-mediated nitroso-redox pathway. These findings demonstrate, for the first time, how stem cell therapy might be antiarrhythmic by suppressing cardiac alternans through paracrine action on Ca(++) cycling.

Antiarrhythmic effect of growth factor-supplemented cardiac progenitor cells in chronic infarcted heart

c-Kit(pos) cardiac progenitor cells (CPCs) represent a successful approach in healing the infarcted heart and rescuing its mechanical function, but electrophysiological consequences are uncertain. CPC mobilization promoted by hepatocyte growth factor (HGF) and IGF-1 improved electrogenesis in myocardial infarction (MI). We hypothesized that locally delivered CPCs supplemented with HGF + IGF-1 (GFs) can concur in ameliorating electrical stability of the regenerated heart. Adult male Wistar rats (139 rats) with 4-wk-old MI or sham conditions were randomized to receive intramyocardial injection of GFs, CPCs, CPCs + GFs, or vehicle (V). Enhanced green fluorescent protein-tagged CPCs were used for cell tracking. Vulnerability to stress-induced arrhythmia was assessed by telemetry-ECG. Basic cardiac electrophysiological properties were examined by epicardial multiple-lead recording. Hemodynamic function was measured invasively. Hearts were subjected to anatomical, morphometric, immunohistochemical, and molecular biology analyses. Compared with V and at variance with individual CPCs, CPCs + GFs approximately halved arrhythmias in all animals, restoring cardiac anisotropy toward sham values. GFs alone reduced arrhythmias by less than CPCs + GFs, prolonging ventricular refractoriness without affecting conduction velocity. Concomitantly, CPCs + GFs reactivated the expression levels of Connexin-43 and Connexin-40 as well as channel proteins of key depolarizing and repolarizing ion currents differently than sole GFs. Mechanical function and anatomical remodeling were equally improved by all regenerative treatments, thus exhibiting a divergent behavior relative to electrical aspects. Conclusively, we provided evidence of distinctive antiarrhythmic action of locally injected GF-supplemented CPCs, likely attributable to retrieval of Connexin-43, Connexin-40, and Cav1.2 expression, favoring intercellular coupling and spread of excitation in mended heart.

Arrhythmia in stem cell transplantation

Stem cell regenerative therapies hold promise for treating diseases across the spectrum of medicine. While significant progress has been made in the preclinical stages, the clinical application of cardiac cell therapy is limited by technical challenges. Certain methods of cell delivery, such as intramyocardial injection, carry a higher rate of arrhythmias. Other potential contributors to the arrhythmogenicity of cell transplantation include reentrant pathways caused by heterogeneity in conduction velocities between graft and host as well as graft automaticity. In this article, the arrhythmogenic potential of cell delivery to the heart is discussed.

Improved conduction and increased cell retention in healed MI using mesenchymal stem cells suspended in alginate hydrogel

INTRODUCTION

Mesenchymal stem cells (MSCs) have been associated with reduced arrhythmias; however, the mechanism of this action is unknown. In addition, limited retention and survival of MSCs can significantly reduce efficacy. We hypothesized that MSCs can improve impulse conduction and that alginate hydrogel will enhance retention of MSCs in a model of healed myocardial infarction (MI).

METHODS AND RESULTS

Four weeks after temporary occlusion of the left anterior descending artery (LAD), pigs (n = 13) underwent a sternotomy to access the infarct and then were divided into two studies. In study 1, designed to investigate impulse conduction, animals were administered, by border zone injection, 9-15 million MSCs (n = 7) or phosphate-buffered saline (PBS) (control MI, n = 5). Electrogram width measured in the border zone 2 weeks after injections was significantly decreased with MSCs (-30 ± 8 ms, p < 0.008) but not in shams (4 ± 10 ms, p = NS). Optical mapping from border zone tissue demonstrated that conduction velocity was higher in regions with MSCs (0.49 ± 0.03 m/s) compared to regions without MSCs (0.39 ± 0.03 m/s, p < 0.03). In study 2, designed to investigate MSC retention, animals were administered an equal number of MSCs suspended in either alginate (2 or 1 % w/v) or PBS (n = 6/group) by border zone injection. Greater MSC retention and survival were observed with 2% alginate compared to PBS or 1% alginate. Confocal immunofluorescence demonstrated that MSCs survive and are associated with expression of connexin-43 (Cx43) for either PBS (control), 1%, or 2% alginate.

CONCLUSIONS

For the first time, we are able to directly associate MSCs with improved impulse conduction and increased retention and survival using an alginate scaffold in a clinically relevant model of healed MI.