title: Endothelial cell coculture within tissue-engineered cardiomyocyte sheets enhances neovascularization and improves cardiac function of ischemic hearts.
abstract: BACKGROUND
  Regenerative therapies, including myocardial tissue engineering, have been pursued as a new possibility to repair the damaged myocardium, and previously the transplantation of layered cardiomyocyte sheets has been shown to be able to improve cardiac function after myocardial infarction. We examined the effects of promoting neovascularization by controlling the densities of cocultured endothelial cells (ECs) within engineered myocardial tissues created using our cell sheet-based tissue engineering approach.
  
  
  RESULTS
  Neonatal rat cardiomyocytes were cocultured with GFP-positive rat-derived ECs on temperature-responsive culture dishes. Cocultured ECs formed cell networks within the cardiomyocyte sheets, which were preserved during cell harvest from the dishes using simple temperature reduction. We also observed significantly increased in vitro production of vessel-forming cytokines by the EC-positive cardiac cell sheets. After layering of 3 cardiac cell sheets to create 3-dimensional myocardial tissues, these patch-like tissue grafts were transplanted onto infarcted rat hearts. Four weeks after transplantation, recovery of cardiac function could be significantly improved by increasing the EC densities within the engineered myocardial tissues. Additionally, when the EC-positive cardiac tissues were transplanted to myocardial infarction models, we observed significantly greater numbers of capillaries in the grafts as compared with the EC-negative cell sheets. Finally, blood vessels originating from the engineered EC-positive cardiac tissues bridged into the infarcted myocardium to connect with capillaries of the host heart.
  
  
  CONCLUSIONS
  In vitro engineering of 3-dimensional cardiac tissues with preformed EC networks that can be easily connected to host vessels can contribute to the reconstruction of myocardial tissue grafts with a high potential for cardiac function repair. These results indicate that neovascularization can contribute to improved cardiac function after the transplantation of engineered cardiac tissues.
authors.affiliation: Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 Japan.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Sekine
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Shimizu
authors.forename: Kyoko
authors.initials: K
authors.lastname: Hobo
authors.forename: Sachiko
authors.initials: S
authors.lastname: Sekiya
authors.forename: Joseph
authors.initials: J
authors.lastname: Yang
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamato
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kurosawa
authors.forename: Eiji
authors.initials: E
authors.lastname: Kobayashi
authors.forename: Teruo
authors.initials: T
authors.lastname: Okano
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002196:Capillaries / Q000473:pathology; D002452:Cell Count; D018920:Coculture Techniques; D003326:Coronary Circulation; D042783:Endothelial Cells / Q000166:cytology / Q000637:transplantation*; D005355:Fibrosis / Q000517:prevention & control; D006321:Heart / Q000503:physiopathology*; D009203:Myocardial Infarction / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D017202:Myocardial Ischemia / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D009206:Myocardium / Q000166:cytology* / Q000473:pathology; D032383:Myocytes, Cardiac / Q000637:transplantation*; D018919:Neovascularization, Physiologic; D011183:Postoperative Complications / Q000517:prevention & control; D051381:Rats; D017207:Rats, Sprague-Dawley; D023822:Tissue Engineering