The Integration and Functional Evaluation of Rabbit Pacing Cells Transplanted into the Left Ventricular Free Wall

Abstract

To evaluate the feasibility of cell transplantation to treat bradyarrhythmia, we analyzed the in vivo integration and pacing function after transplantation of mHCN4-modified rabbit bone marrow mesenchymal stem cells (MSCs) into the rabbit left ventricle free wall epicardium. In our investigation, we injected MSCs transduced with or without mHCN4 into the rabbit left ventricle free wall epicardium. Chemical ablation of the sinoatrial node was performed and bilateral vagus nerves were sequentially stimulated to observe premature left ventricular contraction or left ventricular rhythm. We found that the mHCN4-transduced MSC group had a significantly higher ventricular rate and a shorter QRS duration than that of the control and EGFP group. Furthermore, the mHCN4-transduced MSCs, but not the control cells, gradually adapted long-spindle morphology and became indistinguishable from adjacent ventricle myocytes. The modified MSCs showed pacing function approximately 1 week after transplantation and persisted at least 4 weeks after transplantation. In conclusion, a bradyarrhythmia model can be successfully established by chemical ablation of the sinoatrial node and sequential bilateral vagus nerve stimulation. The mHCN4-modified rabbit MSCs displayed evident dynamic morphology changes after being transplanted into rabbit left ventricle free wall epicardium. Our studies may provide a promising strategy of using modified stem cell transplantation to treat bradyarrhythmia.

Bioengineering the Cardiac Conduction System: Advances in Cellular, Gene, and Tissue Engineering for Heart Rhythm Regeneration

“…In other animal studies based on hMSCs transduced with HCN1, HCN2, or HCN4, the ability of electrical coupling with cardiomyocytes and the generation of I f current were also confirmed (Zhang et al, 2012;Nong et al, 2013;Zhou et al, 2013). As recently reviewed by Pittenger et al (2019), hMSCs have aroused an incredible translational interest in many cell therapy applications due to their peculiar repertoire of major histocompatibility complex (MHC) molecules, antiinflammatory paracrine effect, and ability to suppress mixed lymphocyte reactions, which render them immunotolerated in allogeneic donations, too.…”

“…Animal studies were performed with the primary goal to evaluate the efficacy, safety, stability, and other parameters of the different biological pacemaker approaches. Biological pacemaking was achieved in the majority of these models, which vary depending on the animal, duration of observation, delivery method, and time stability (Edelberg et al, 1998 ; Edelberg, 2001 ; Miake et al, 2002 ; Ruhparwar et al, 2002 , 2010 ; Qu et al, 2003 ; Plotnikov et al, 2004 , 2007 , 2008 ; Potapova et al, 2004 ; Lin et al, 2005 ; Xue et al, 2005 ; Bucchi et al, 2006 ; Tse et al, 2006 ; Cai et al, 2007 ; Cho et al, 2007 ; Piron et al, 2008 ; Shlapakova et al, 2010 ; Zhang et al, 2011 , 2012 ; Boink et al, 2012a , b ; Cingolani et al, 2012 ; Kapoor et al, 2013 ; Morris et al, 2013 ; Nong et al, 2013 ; Hu et al, 2014 ; Ionta et al, 2015 ; Protze et al, 2016 ; Chauveau et al, 2017 ; Choudhury et al, 2018 ; Dawkins et al, 2019 ; Gorabi et al, 2019a ; Végh et al, 2019 , 2021 ).…”

“…For all approaches pursued for biopacemaking, it is fundamental to find adequate delivery modalities that are easy to perform, minimally invasive, associated with low peri-intervention risks, and able to guarantee the sustained effect in vivo . Most gene or cell delivery methods are still invasive (open chest or thoracotomy), representing less attractive options for the future clinical application in humans (Miake et al, 2002 ; Ruhparwar et al, 2002 , 2010 ; Qu et al, 2003 ; Potapova et al, 2004 ; Lin et al, 2005 ; Xue et al, 2005 ; Choi et al, 2006 ; Tse et al, 2006 ; Cai et al, 2007 ; Cho et al, 2007 ; Plotnikov et al, 2007 ; Boink et al, 2012a , 2013 ; Zhang et al, 2012 ; Kapoor et al, 2013 ; Nong et al, 2013 ; Ionta et al, 2015 ; Protze et al, 2016 ; Chauveau et al, 2017 ; Gorabi et al, 2019a ). The development of minimally invasive, safer, and well-controlled delivery methods is a current research priority of biological pacemakers in the field of regenerative medicine.…”

“…Typically, biological pacemaker activity and pro-arrhythmic effects were monitored by in vivo and ex vivo assessment. ECG, serial Holter monitoring, pacemaker log recordings, patch clamp, non-fluoroscopic magnetic electroanatomic system (CARTO), and optical mapping of the epicardial electrical activity in perfused, excided hearts are often employed to analyze biopacing activity (Miake et al, 2002 , 2003 ; Ruhparwar et al, 2002 , 2010 ; Qu et al, 2003 ; Xue et al, 2005 ; Choi et al, 2006 ; Tse et al, 2006 ; Plotnikov et al, 2007 , 2008 ; Shlapakova et al, 2010 ; Zhang et al, 2012 , 2017 ; Kapoor et al, 2013 ; Nong et al, 2013 ; Gorabi et al, 2019a ). In vivo evaluations are more indicative of the induced biopacemaking activity because they allow to study electrical function in the living animal and assess the global function.…”

“…Despite the abundance of animal studies, a comprehensive evaluation of safety, long-term stability, arrhythmogenicity, and toxicity remains still to be realized to date. Various in vivo dysfunctional rhythm models were successfully created to simulate, e.g., bradyarrhythmia, sick sinus syndrome, and AV block (Qu et al, 2003 ; Kehat et al, 2004 ; Plotnikov et al, 2004 , 2007 , 2008 ; Bucchi et al, 2006 ; Tse et al, 2006 ; Shlapakova et al, 2010 ; Zhang et al, 2012 ; Hu et al, 2014 ), by allowing to effectively test any one of the developed biopacemaker therapeutic concepts.…”