Introduction A comparative analysis of the efficacy of different cell candidates for the treatment of heart disease remains to be described. This study is designed to evaluate the therapeutic efficacy of 4 cell types in a murine model of myocardial infarction. Methods Bone marrow mononuclear cells (MN), mesenchymal stem cells (MSC), skeletal myoblasts (SkMb) and fibroblasts (Fibro) were isolated from male L2G transgenic mice (FVB background) that constitutively express firefly luciferase (Fluc) and green fluorescence protein (GFP). Cells were characterized by flow cytometry, bioluminescence imaging (BLI), and luminometry. Female FVB mice (n=60) underwent LAD ligation and were randomized into 5 groups to intramyocardially receive one cell type (5 × 105) or PBS as control. Cell survival was measured in vivo by BLI and ex vivo by TaqMan PCR at week 6. Cardiac function was assessed by echocardiography and invasive hemodynamic measurements were made at week 6. Results Fluc expression correlated with the cell number in all groups (r2 >0.93). In vivo BLI revealed acute donor cell death of MSC, SkMb, and Fibro within 3 weeks after transplantation. By contrast, cardiac signals were still present after 6 weeks in the MN group, as confirmed by TaqMan PCR (P<0.01). Echocardiography showed significant preservation of fractional shortening in the MN group compared to controls (P<0.05). Measurements of left ventricular end-systolic/diastolic volumes revealed that the least amount of ventricular dilatation occurred in the MN group (P<0.05). Histology confirmed the presence of MN, although there was no evidence of transdifferentiation by donor MN into cardiomyocytes. Conclusion This is the first study to directly compare a variety of cell candidates for myocardial therapy. Compared to MSC, SkMB, and Fibro, our results suggest that MN cells exhibit a more favorable survival pattern, which translates into a more robust preservation of cardiac function.

Bone marrow mononuclear cell (BMMC) therapy shows promise as a treatment for ischemic heart disease. However, the ability to monitor long-term cell fate remains limited. We hypothesized that molecular imaging could be used to track stem cell homing and survival after myocardial ischemia-reperfusion (I/R) injury. We first harvested donor BMMCs from adult male L2G85 transgenic mice constitutively expressing both firefly luciferase (

Background Mesenchymal stem cells hold promise for cardiovascular regenerative therapy. Derivation of these cells from the adipose tissue might be easier compared to bone marrow. However, the in vivo fate and function of adipose stromal cells (ASC) in the infarcted heart has never been compared directly to bone marrow derived mesenchymal cells (MSC). Methods ASC and MSC were isolated from transgenic FVB mice with β-actin promoter driving firefly luciferase and green fluorescent protein (Fluc-GFP) double fusion reporter gene, and were characterized using flow cytometry, microscopy, bioluminescence imaging (BLI) and luminometry. FVB mice (n=8/group) underwent myocardial infarction followed by intramyocardial injection of 5×105 ASC, MSC, fibroblasts (Fibro, positive control), or saline (negative control). Cell survival was measured using BLI for 6 weeks and cardiac function was monitored by echocardiography and pressure-volume (PV) analysis. Ventricular morphology was assessed using histology. Results ASC and MSC were CD34−, CD45−, c-Kit−, CD90+, Sca-1+, shared similar morphology, and had a population doubling time of ∼2 days. Cells expressed Fluc reporter genes in a number-dependent fashion, as confirmed by luminometry. After cardiac transplantation, both cell types showed drastic donor cell death within 4−5 weeks. Furthermore, transplantation of either cell type was not capable of preserving ventricular function and dimensions, as confirmed by PV-loops and histology. Conclusion This is the first study comparing the in vivo behavior of both cell types in the infarcted heart. ASC and MSC do not tolerate well in the cardiac environment, resulting in acute donor cell death and a subsequent loss of cardiac function similar to control groups.

Pluripotent embryonic stem (ES) cells have the potential to form teratomas composed of derivatives from all three germ layers in animal models. This tumorigenic potential prevents clinical translation of ES cell research. In order to understand the biology and physiology of teratoma formation, we investigated the influence of undifferentiated ES cell number, migration, and long-term follow up after transplantation. Murine ES cells were stably transduced with a self-inactivating (SIN) lentiviral vector with a constitutive ubiquitin promoter driving a double-fusion (DF) reporter gene that consists of firefly luciferase and enhanced green fluorescent protein (Fluc-eGFP). To assess effects of cell numbers, varying numbers of ES-DF cells (1, 10, 100, 1,000, and 10,000) were injected subcutaneously into the dorsal regions of adult nude mice. To assess cell migration, 1 x 10(6) ES-DF cells were injected intramyocardially into adult Sv129 mice, and leakage to other extracardiac sites was monitored. To assess effects of long-term engraftment, 1 x 10(4) ES-DF cells were injected intramyocardially into adult nude rats, and cell survival response was monitored for 10 months. Our results show that ES-DF cells caused extracardiac teratoma in both immunocompetent and immunodeficient hosts; the lowest number of undifferentiated ES cells capable of causing teratoma was 500-1,000; and long-term engraftment could be shown for >300 days. Collectively, these results illustrate the potent tumorigenic potential of ES cells, which presents an enormous obstacle for future clinical studies.

Background Despite ongoing clinical trials, the optimal time for delivery of bone marrow mononuclear cells (BMCs) following myocardial infarction (MI) is unclear. We compared the viability and effects of transplanted BMCs on cardiac function in the acute and sub-acute inflammatory phases of MI. Methods and Results The time-course of acute inflammatory cell infiltration was quantified by FACS analysis of enzymatically digested hearts of FVB mice (n=12) following LAD ligation. Mac-1+Gr-1high neutrophil infiltration peaked at day 4. BMCs were harvested from transgenic FVB mice expressing firefly luciferase (Fluc) and green fluorescent protein (GFP). Afterwards, 2.5×106 BMCs were injected into the left ventricle of wild-type FVB mice either immediately (Acute BMC) or 7 days (Sub-acute BMC) after MI, or after a sham procedure (n=8 per group). In vivo bioluminescence imaging (BLI) showed an early signal increase in both BMC groups at day 7, followed by a non-significant trend (P=0.203) towards improved BMC survival in the Sub-acute BMC group that persisted until the BLI signal reached background levels after 42 days. Compared to controls (MI + saline injection), echocardiography showed a significant preservation of fractional shortening at 4 weeks (Acute BMC vs saline; P<0.01) and 6 weeks (both BMC groups vs saline; P<0.05), but no significant differences between the two BMC groups. FACS analysis of BMC injected hearts at day 7 revealed that GFP+ BMCs expressed hematopoietic (CD45, Mac-1, Gr-1), minimal progenitor (Sca-1, c-kit), and no endothelial (CD133, Flk-1) or cardiac (Trop-T) cell markers. Conclusion Timing of BMC delivery has minimal effects on intramyocardial retention and preservation of cardiac function. In general, there is poor long-term engraftment and BMCs tend to adopt inflammatory cell phenotypes.

This large series of surgically-treated CBTs supports craniocaudal dissection as the surgical technique of choice as it limits blood loss and facilitates safe CBT resection.

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