A novel application of myocardial contrast echocardiography to evaluate angiogenesis by autologous bone marrow cell transplantation in chronic ischemic pig model Original Research Article

Objectives We investigated the feasibility of myocardial contrast echocardiography (MCE) to evaluate regional perfusion after bone marrow cell transplantation. Background The myocardial microvessels improved by cell transplantation are too small to visualize with conventional angiography. Methods Fourteen mini-pigs from the Nippon Institute for Biological Science were used. The proximal left anterior descending coronary artery was ligated. One month later, nine pigs survived. Six pigs received autologous cell transplantation into the left ventricular anterior wall: bone marrow mononuclear cells (BMMNCs) (n = 3) and bone marrow stromal cells (BMSCs) (n = 3). The other three pigs received saline (control group, n = 3). The pigs were sacrificed one month later. Myocardial contrast intensity (MCI) with a contrast agent was measured using the SONOS 5500 system (Philips). Capillary density (CD) and MCI were measured at four areas: anteroseptum (nontransplanted infarct area), anterior wall (transplanted infarct area), septum (border zone), and lateral wall (normal). We compared the anteroseptum with the anterior wall by MCI and CD. Results In the BMMNC and BMSC subsets, the CD of the anterior wall was higher than that of the anteroseptum (p < 0.001). There was a linear relation between MCI and CD (acoustic unit [AU2] = 0.234 CD + 0.010, r = 0.92, p < 0.001). At one month after cell transplantation, MCI of the anterior wall increased in the BMMNC and BMSC subsets (p < 0.05), although it did not change in the control group. The ratio of wall thickness (systole/diastole) in the transplanted infarct area was larger than that in the nontransplanted infarct area (p < 0.01). Conclusions Myocardial contrast echocardiography is useful to evaluate regional perfusion, which was enhanced by bone marrow cell transplantation.