Epicardial transplantation of autologous atrial appendage micrografts: evaluation of safety and feasibility in pigs after coronary artery occlusion.

Objectives. Several approaches devised for clinical utilization of cell-based therapies for heart failure often suffer from complex and lengthy preparation stages. Epicardial delivery of autologous atrial appendage micrografts (AAMs) with a clinically used extracellular matrix (ECM) patch provides a straightforward therapy alternative. We evaluated the operative feasibility and the effect of micrografts on the patch-induced epicardial foreign body inflammatory response in a porcine model of myocardial infarction. Design. Right atrial appendages were harvested and mechanically processed into AAMs. The left anterior descending coronary artery was ligated to generate acute infarction. Patches of ECM matrix with or without AAMs were transplanted epicardially onto the infarcted area. Four pigs received the ECM and four received the AAMs patch. Cardiac function was studied by echocardiography both preoperatively and at 3-week follow-up. The primary outcome measures were safety and feasibility of the therapy administration, and the secondary outcome was the inflammatory response to ECM. Results. Neither AAMs nor ECM patch-related complications were detected during the follow-up time. AAMs patch preparation was feasible according to time and safety. Inflammation was greatly reduced in AAMs when compared with ECM patches as measured by the amount of infiltrated inflammatory cells and area of inflammation. Immunohistochemistry demonstrated an increased CD3+ cell density in the AAMs patch infiltrate. Conclusions. Epicardial AAMs transplantation demonstrated safety and clinical feasibility. The use of micrografts significantly inhibited ECM-induced foreign body inflammatory reactivity. Transplantation of AAMs shows good clinical applicability as adjuvant therapy to cardiac surgery and can suppress acute inflammatory reactivity.

Use of left atrial appendage as an autologous tissue source for epicardial micrograft transplantation during LVAD implantation.

We report here the first clinical use of the left atrial appendage (LAA) for epicardial micrograft transplantation during left ventricular assist device (LVAD) implantation. Previously, a sample from the right atrial appendage (RAA) has been available for processing and administering micrograft therapy in cardiac surgery. Both LAA and RAA are rich sources of various types of myocardial cells and are capable of providing both paracrine and cellular support to the failing myocardium. The surgical approach of LAA micrografting facilitates epicardial micrograft therapy dose escalation and treatment of larger myocardial areas than done previously. Moreover, as collection of treated vs. untreated tissues from the recipient heart is possible following LVAD implantation at the time of heart transplantation, the evaluation of the therapy's mechanism of action can be further deciphered at cellular and molecular levels. This LAA modification of the epicardial micrografting technique has the overall potential to facilitate the adoption of cardiac cell therapy during heart surgery.

Effect of transplantation of bone marrow stem cells on myocardial infarction size in a rabbit model.

BACKGROUND: Intravenous transplantation has been regarded as a most safe method in stem cell therapies. There is evidence showing the homing of bone marrow stem cells (BMSCs) into the injured sites, and thus these cells can be used in the treatment of acute myocardial infarction (MI). This study aimed to investigate the effect of intravenous and epicardial transplantion of BMSCs on myocardial infarction size in a rabbit model. METHODS: A total of 60 New Zealand rabbits were randomly divided into three groups: control group, epicardium group (group I) and ear vein group (group II). The BMSCs were collected from the tibial plateau in group I and group II, cultured and labeled. In the three groups, rabbits underwent thoracotomy and ligation of the middle left anterior descending artery. The elevation of ST segment >0.2 mV lasting for 30 minutes on the lead II and III of electrocardiogram suggested successful introduction of myocardial infarction. Two weeks after myocardial infarction, rabbits in group I were treated with autogenous BMSCs at the infarct region and those in group II received intravenous transplantation of BMSCs. In the control group, rabbits were treated with PBS following thoracotomy. Four weeks after myocardial infarction, the heart was collected from all rabbits and the infarct size was calculated. The heart was cut into sections followed by HE staining and calculation of infarct size with an image system. RESULTS: In groups I and II, the infarct size was significantly reduced after transplantation with BMSCs when compared with the control group (P<0.05). However, there was no significant difference in the infarct size between groups I and II (P>0.05). CONCLUSION: Transplantation of BMSCs has therapeutic effect on MI. Moreover, epicardial and intravenous transplantation of BMSCs has comparable therapeutic efficacy on myocardial infarction.

Effect of transplantation of bone marrow stem cells on myocardial infarction size in a rabbit model / 世界急诊医学杂志（英文）

@#BACKGROUND: Intravenous transplantation has been regarded as a most safe method in stem cell therapies. There is evidence showing the homing of bone marrow stem cells (BMSCs) into the injured sites, and thus these cells can be used in the treatment of acute myocardial infarction (MI). This study aimed to investigate the effect of intravenous and epicardial transplantion of BMSCs on myocardial infarction size in a rabbit model. METHODS: A total of 60 New Zealand rabbits were randomly divided into three groups: control group, epicardium group (group I) and ear vein group (group II). The BMSCs were collected from the tibial plateau in group I and group II, cultured and labeled. In the three groups, rabbits underwent thoracotomy and ligation of the middle left anterior descending artery. The elevation of ST segment>0.2 mV lasting for 30 minutes on the lead II and III of electrocardiogram suggested successful introduction of myocardial infarction. Two weeks after myocardial infarction, rabbits in group I were treated with autogenous BMSCs at the infarct region and those in group II received intravenous transplantation of BMSCs. In the control group, rabbits were treated with PBS following thoracotomy. Four weeks after myocardial infarction, the heart was collected from all rabbits and the infarct size was calculated. The heart was cut into sections followed by HE staining and calculation of infarct size with an image system. RESULTS: In groups I and II, the infarct size was significantly reduced after transplantation with BMSCs when compared with the control group (P<0.05). However, there was no significant difference in the infarct size between groups I and II (P>0.05). CONCLUSION: Transplantation of BMSCs has therapeutic effect on MI. Moreover, epicardial and intravenous transplantation of BMSCs has comparable therapeutic efficacy on myocardial infarction.