Biomedical Engineering Reference
In-Depth Information
Figure 2a.1
Scheme of paracrine effects in stem/progenitor cell transplan-
tation to the injured heart.
mononuclear cells for acute myocardial infarction and chronic
ischemic heart disease. A recent meta-analysis demonstrated that
the therapy improved left ventricular ejection fraction by 5.4% and
reduced infarct scar size and left ventricular end-systolic volume by
5.5% and 4.8 mL, respectively [4]. Although in vivo differentiation
of bone marrow mononuclear cells into cardiomyocytes remains a
topic for debate, endothelial progenitor cells (EPCs) are found in
the bone marrow mononuclear cell population, and regeneration of
blood vessels from these EPCs is expected to improve blood flow.
A study using an animal model of myocardial ischemia showed the
presence of vascular endothelial cells derived from transplanted
EPCs, increases in capillary density, and improvements in cardiac
function after transplantation of EPCs [5]. Moreover, a model
using genetically engineered bone marrow mononuclear cells
carrying suicide genes revealed that the improvements in left
ventricular ejection fraction and increases in capillary density after
transplantation were reversed when bone marrow-derived vascular
endothelial or smooth muscle cells were selectively depleted through
the suicide mechanism [6]. These results suggest that cardiovascular
