Survival and function of mouse embryonic stem cell-derived cardiomyocytes in ectopic transplants.
OBJECTIVE
Embryonic stem cell-derived cardiomyocytes are a useful source for cell transplantation into the heart, as well as for tissue engineering of the extracardiac vascular system. The present study was designed to investigate the survival and contractile function of embryonic stem cell-derived cardiomyocytes around large blood vessels to assess the feasibility of their ectopic use for future engineering of cardiovascular tissues.


METHODS
The mouse embryonic stem cell-derived cardiomyocytes were transplanted into the retroperitoneum of the adult nude mice, and the myocardial tissues that developed were characterized by electrophysiological and histological techniques.


RESULTS
Macroscopic and electrophysiological analyses showed spontaneously contracting transplants in the host retroperitoneum 7 and 30 days after transplantation. Immunohistochemistry detected developing cardiomyocytes in the transplants on Day 7, which formed the myocardial tissues. They were positive for cardiac troponin I, cadherin, connexin 43, and proliferating cell nuclear antigen, but negative for alpha-smooth muscle actin. Vascular formation was discernible in the transplant tissues. By Day 30, more mature myocardial tissues had been established in the transplants. Electron microscopic study emphasized that the transplant tissues comprised cardiomyocytes, in which myofibrils with organized sarcomeres were observed. Desmosomes, fasciae adherens and gap junctions were evident in the cellular junctions.


CONCLUSIONS
The cardiomyocytes derived from the mouse ES cells were demonstrated to be viable and function in the ectopic site of the host retroperitoneum up to Day 30, following a process of proliferation and differentiation. Vascularization and host perfusion beneficial for the survival of the cardiomyocytes occurred in the transplants.
Johkura
Kohei
K
Department of Anatomy and Organ Technology, Shinshu University School of Medicine, 3-1-1 Asahi, 390-8621, Matsumoto, Japan. kohei@sch.md.shinshu-u.ac.jp
Cui
Li
L
Suzuki
Akihiro
A
Teng
Ruifeng
R
Kamiyoshi
Akiko
A
Okamura
Shintaro
S
Kubota
Suguru
S
Zhao
Xu
X
Asanuma
Kazuhiko
K
Okouchi
Yasumitsu
Y
Ogiwara
Naoko
N
Tagawa
Yoh ichi
Yi
Sasaki
Katsunori
K
D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001808:Blood Vessels; D015820:Cadherins / Q000032:analysis; D002454:Cell Differentiation; D002470:Cell Survival; D002828:Choristoma; D018031:Connexin 43 / Q000032:analysis; D007150:Immunohistochemistry / Q000379:methods; D051379:Mice; D008819:Mice, Nude; D008854:Microscopy, Electron; D023421:Models, Animal; D009200:Myocardial Contraction; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000648:ultrastructure; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D033581:Stem Cell Transplantation; D014184:Transplantation, Homologous; D019210:Troponin I / Q000032:analysis
D015415:Biomarkers; D015820:Cadherins; D018031:Connexin 43; D018809:Proliferating Cell Nuclear Antigen; D019210:Troponin I