Effect of Shenfu Injection on Differentiation of Bone Marrow Mesenchymal Stem Cells into Pacemaker-Like Cells and Improvement of Pacing Function of Sinoatrial Node.

Qi Chen,Song Wang,Rong Li,Wei Wu,Lijin Qing,Zina Lin,Yinhe Cai,Yihua Li,Xinjun Zhao,Qingmin Chu,Liang Kang,Imtaiyaz Hassan

doi:10.1155/2022/4299892

Abstract

Sick sinus syndrome (SSS), a complex type of cardiac arrhythmia, is a major health threat to humans. Shenfu injection (SFI), a formula of traditional Chinese medicine (TCM), is effective in improving bradyarrhythmia. However, the underlying mechanism of SFI's therapeutic effect is subject to few systematic investigations. The purpose of the present research is to examine whether SFI can boost the differentiation effectiveness of bone marrow mesenchymal stem cells (BMSCs) into pacemaker-like cells and whether the transplantation of these cells can improve the pacing function of the sinoatrial node (SAN) in a rabbit model of SSS. BMSCs from New Zealand rabbits were extracted, followed by incubation in vitro. The flow cytometry was utilized to identify the expression of CD29, CD44, CD90, and CD105 surface markers. The isolated BMSCs were treated with SFI, and the whole-cell patch-clamp method was performed to detect hyperpolarization-the activated cyclic nucleotide-gated potassium channel 4 (HCN4) channel current activation curve. The SSS rabbit model was established using the formaldehyde wet dressing method, and BMSCs treated with SFI were transplanted into the SAN of the SSS rabbit model. We detected changes in the body-surface electrocardiogram and recorded dynamic heart rate measurements. Furthermore, transplanted SFI-treated BMSCs were subjected to HE staining, TUNEL staining, qPCR, western blotting, immunofluorescence, immunohistochemistry, and enzyme-linked immunosorbent assay to study their characteristics. Our results indicate that the transplantation of SFI-treated BMSCs into the SAN of SSS rabbits improved the pacing function of the SAN. In vitro data showed that SFI induced the proliferation of BMSCs, promoted their differentiation capacity into pacemaker-like cells, and increased the HCN4 expression in BMSCs. In vivo, the transplantation of SFI treated-BMSCs preserved the function of SAN in SSS rabbits, improved the expression of the HCN4 gene and gap junction proteins (Cx43 and Cx45), and significantly upregulated the expression of cAMP in the SAN, compared to the SSS model group. In summary, the present research demonstrated that SFI might enhance the differentiation capacity of BMSCs into pacemaker-like cells, hence offering a novel approach for the development of biological pacemakers. Additionally, we confirmed the effectiveness and safety of pacemaker-like cells differentiated from BMSCs in improving the pacing function of the SAN.

Highlights

Sick sinus syndrome (SSS) comprises various cardiac conditions, such as the abnormal pacing of the sinoatrial node (SAN) or alterations of conduction function, which leads to abnormalities in the heart rhythm, such as sinus arrest, SAN exit block, and sinus bradycardia
We investigated the function of Shenfu injection (SFI) in the differentiation of bone marrow mesenchymal cells (BMSCs) into pacemaker-like cells
Patients suffering from bradyarrhythmia might gain benefit from the use of biological pacemakers that could be manufactured through gene or cell therapy to reestablish cardiac rhythm as well as conduction functionality [29]

Summary

Introduction

Sick sinus syndrome (SSS) comprises various cardiac conditions, such as the abnormal pacing of the sinoatrial node (SAN) or alterations of conduction function, which leads to abnormalities in the heart rhythm (arrhythmias), such as sinus arrest, SAN exit block, and sinus bradycardia. For the purpose of circumventing the limitations and negative impacts of electronic pacemakers, stem cell-based biological pacemakers have been widely investigated so as to initiate the spontaneous activity of formerly quiescent cardiomyocytes [3,4,5]. As a marker for pacemaker cells of the heart, HCN4 drives the generation of the pacemaker current (I f , referred to as funny current) and the maintenance of sinus rhythm [9, 10]. Knockout of HCN4 in adult mice or human cause cardiac arrhythmia with a reduction in I f in the SAN [12, 13]

Objectives

Results

Conclusion