Abstract 4294: Migration of Intramyocardially Injected Porcine Mesenchymal Stem Cells in Remote Healthy Organs
Objectives. Porcine bone marrow-derived mesenchymal stem cells (MSC) were stably transfected with a lentiviral vector for transgene expression of the trifusion protein renilla luciferase, red fluorescent protein and herpes simplex truncated thymidine kinase (LV-RL-RFP-tTK) for tracking of the intramyocardially delivered MSC in the myocardium and remote organs.
Methods. Closed-chest, reperfused myocardial infarction was created in farm pigs under general anesthesia. LV-RL-RFP-tTK-MSC (4.6±1.2 ×106) were injected percutaneously intramyocardially using electromechanical mapping guidance 16 days post-MI in the infarct border zone. Tissue samples (1.45±0.11 g) were collected 16h (n=4) and 8 days (n=6) post-delivery of LV-RL-RFP-tTK-MSC from the infarcted (injected and non-injected) and normal myocardium and different organs. Luciferase activity was measured in the homogenized tissues using components of the Dual-Luciferase Reporter Assay and expressed in relative light units (RLU) per μg protein.
Results. Luciferase activity decreased in the injected myocardial area from 16h to 8±1 days while it increased significantly in the infarcted non-treated myocardium and remained at the level of the negative control in the noninfarcted myocardium (51±27 and 68±18 RLU/μg protein at 16h and 8±1 days, respectively). Significantly increased luciferase activity was measured at 8±1 days in the mediastinal lymph nodes, liver, spleen and bone marrow. The luciferase level was slightly elevated in the pericardium and pleura at 16h, which increased nonsignificantly at 8 days. The presence of the LV-RL-RFP-tTK-MSC in the myocardium (5.7% of injected cells) and lymph nodes was confirmed by fluorescence confocal microscopy.
Conclusions. Reporter gene imaging enables the tracking of the persistence of viable LV-RL-RFP-tTK-MSC in the peri-infarcted porcine myocardium and the migration of the intramyocardially delivered MSC in remote healthy organs.