Ferritin as a reporter gene for in vivo tracking of stem cells by 1.5-T cardiac MRI in a rat model of myocardial infarction

Abstract

The methods currently utilized to track stem cells by cardiac MRI are affected by important limitations, and new solutions are needed. We tested human ferritin heavy chain (hFTH) as a reporter gene for in vivo tracking of stem cells by cardiac MRI. Swine cardiac stem/progenitor cells were transduced with a lentiviral vector to overexpress hFTH and cultured to obtain cardiospheres (Cs). Myocardial infarction was induced in rats, and, after 45 min, the animals were subjected to intramyocardial injection of ∼200 hFTH-Cs or nontransduced Cs or saline solution in the border zone. By employing clinical standard 1.5-Tesla MRI scanner and a multiecho T2* gradient echo sequence, we localized iron-accumulating tissue only in hearts treated with hFTH-Cs. This signal was detectable at 1 wk after infarction, and its size did not change significantly after 4 wk (6.33 ± 3.05 vs. 4.41 ± 4.38 mm(2)). Cs transduction did not affect their cardioreparative potential, as indicated by the significantly better preserved left ventricular global and regional function and the 36% reduction in infarct size in both groups that received Cs compared with control infarcts. Prussian blue staining confirmed the presence of differentiated, iron-accumulating cells containing mitochondria of porcine origin. Cs-derived cells displayed CD31, α-smooth muscle, and α-sarcomeric actin antigens, indicating that the differentiation into endothelial, smooth muscle and cardiac muscle lineage was not affected by ferritin overexpression. In conclusion, hFTH can be used as a MRI reporter gene to track dividing/differentiating stem cells in the beating heart, while simultaneously monitoring cardiac morpho-functional changes.

A Lentiviral Vector-Based, Herpes Simplex Virus 1 (HSV-1) Glycoprotein B Vaccine Affords Cross-Protection against HSV-1 and HSV-2 Genital Infections

“…In one of these studies, porcine cardiac stem cells were transduced ex vivo, implanted in rats with myocardial infarction, and monitored for 3 months by nuclear magnetic resonance imaging. The cells survived, differentiated, and expressed the transduced reporter gene throughout the observation period, a clear indication that LAW34 does not harm or affect physiological functions of implanted cells and the delivered gene is expressed for protracted periods of time (8). The use of LAW34 for vaccination was prompted by an earlier study in which we demonstrated that this vector transduced DCs very efficiently when pseudotyped with RD/114 (43).…”

“…FIV is a lentivirus in domestic cats and similar to HIV-1 in many respects, including genomic organization, but is unable to infect humans (20). Vectors derived from FIV have been successfully used to transduce primary cells from feline and nonfeline species (24,52), including humans (60), and proved safe in vitro and in vivo (4,8,52).…”

Tracking stem cells with superparamagnetic iron oxide nanoparticles: perspectives and considerations

“…Histologic analysis also indicated that ferritin overexpression did not affect cell differentiation. 130 Chung et al used a reporter gene designed to express the antigens hemagglutinin A and myc on the surface of embryonic stem cells. 131 Then, they conjugated SPIONs with monoclonal antibodies against the antigens.…”

Cardiac magnetic resonance, transthoracic and transoesophageal echocardiography: a comparison of in vivo assessment of ventricular function in rats

“…Accordingly, the utility of small animal imaging on 1.5 T scanners is of significant interest to potential investigators. At present, reports have documented the utility of 1.5 T CMR in evaluating cardiac structure/function for MI, 7,12,15 myocarditis, 16 transplant rejection, 11,13 stem cell tracking 10 and myocardial mass. 17 In only one study was an alternative imaging modality used to provide a comparison, 7 which demonstrated a high correlation between single slice CMR and transthoracic M-mode FS (r ¼ 0.86).…”