Effects of umbilical cord blood endothelial progenitor cell transplantation on angiogenesis following myocardial infarction

Bo LI; Hongguang ZHAO; Hong ZHONG; Ruijun LIU; Nan MA; Genfa SHAN; Ju MEI; Fuxian ZHANG; Guoqing LI

ABSTRACT

BACKGROUND:

Endothelial progenitor calls are the cells that can form new blood vessels in the way of angiogenesis in the body,which updates the conventional theory of angiogenesis, vascular damage and repair after birth and provides new ideas for research and treatment of ischemic diseases.

OBJECTIVE:

To investigate the effects of dog umbilical cord blood endothelial progenitor call (UCB-EPC) transplantation on angiogenesis after myocardial infarction.DESIGN, TIME AND

SETTING:

An in vivo cytological experiment was performed at the Laboratory Center of Xinhua Hospital between May 2006 and March 2007.MATERIALS One full-term pregnant hybrid dog was included for preparation of UCB-EPCs. Thirty-six adult dogs were randomly divided into a cell transplantation group (n = 18) and a model control group (n = 18).

METHODS:

Acute myocardial infarction model was established in each group by ligation of antedor descending coronary artery.In the cell transplantation group, 2 mL physiological saline containing 5×10<'6> BrdU-labeled EPCs was injected into the coronary artery, while in the model control group, simple physiological saline of the same amount was given. At 1,4, and 8 weeks after transplantation, dogs were sacrificed for harvesting myocardial tissue.MAIN OUTCOME

MEASURES:

Myocardial infarction was confirmed by hematoxylin-eosin staining. Myocardial angiogenesis was observed by BrdU immunohistochemical staining. The number of infarcted myocardial vessels was calculated by yon Willebrand (vW) factor staining.

RESULTS:

There was plenty of scar tissue, flbroblasts, and small vessels in the myocardial infarction region. In the cell transplantation group, brown yellow particles (BrdU-positive expression) appeared in some nuclei in small vessels from infarcted myocardium. Newly formed vessels were not found in the model control group. In the cell transplantation group, brown yellow particles (vW factor-positive expression) appeared in the cytoplasm of the vascular endothelial cells in the myocardial ischemia and infarction regions, vW factors were not expressed in the model control group. At 1, 4, and 8 weeks after myocardial infarction,there was no significant difference in vessel counts no matter in myocardial ischemia region or in myocardial infarction region between the call transplantation and model control groups.

CONCLUSION:

EPCs derived from UCB of pregnant dog can participate in the formation of blood vessels but can not promote angiogenesis after acute myocardial infarction.