title: Cardiac cell sheet transplantation improves damaged heart function via superior cell survival in comparison with dissociated cell injection.
abstract: Regenerative therapies have currently emerged as one of the most promising treatments for repair of the damaged heart. Recently, numerous researchers reported that isolated cell injection treatments can improve heart function in myocardial infarction models. However, significant cell loss due to primary hypoxia or cell wash-out and difficulty to control the location of the grafted cells remains problem. As an attempt to overcome these limitations, we have proposed cell sheet-based tissue engineering, which involves stacking confluently cultured cells (two-dimensional), cell sheets, to construct three-dimensional cell-dense tissues. Cell sheet transplantation has been able to recover damaged heart function. However, no detailed analysis for transplanted cell survival has been previously performed. The present study compared the survival of cardiac cell sheet transplantation to direct cell injection in a rat myocardial infarction model. Luciferase-expressing neonatal rat cardiac cells were harvested as cell sheets from temperature-responsive culture dishes. The transplantation of cell sheets was compared to the direct injection of isolated cells dissociated with trypsin-ethylenediaminetetraacetic acid. These grafts were transplanted to infarcted rat hearts and cardiac function was assessed by echocardiography at 2 and 4 weeks after transplantation. In vivo bioluminescence and histological analyses were performed to examine cell survival. Cell sheet transplantation consistently yielded greater cell survival than cell injection. Immunohistochemistry revealed that cardiac cell sheets existed over the infarcted area as an intact layer. In contrast, the injected cells were scattered with relatively few cardiomyocytes in the infarcted areas. Four weeks after transplantation, cardiac function was also significantly improved in the cell sheet transplantation group compared with the cell injection. Twenty-four hours after cell grafting, significantly greater numbers of mature capillaries were also observed in the cardiac cell sheet transplantation. Additionally, the numbers of apoptotic cells with deterioration of integrin-mediated attachment were significantly lower after cardiac cell sheet transplantation. In accordance with increased cell survival, cardiac function was significantly improved after cardiac cell sheet transplantation in comparison to cell injection. Cell sheet transplantation can repair damaged hearts through improved cell survival and should become a promising therapy in cardiovascular regenerative medicine.
authors.affiliation: Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University (TWIns), Tokyo, Japan.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Sekine
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Shimizu
authors.forename: Izumi
authors.initials: I
authors.lastname: Dobashi
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Matsuura
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Hagiwara
authors.forename: Masafumi
authors.initials: M
authors.lastname: Takahashi
authors.forename: Eiji
authors.initials: E
authors.lastname: Kobayashi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamato
authors.forename: Teruo
authors.initials: T
authors.lastname: Okano
mesh_terms: D000818:Animals; D017209:Apoptosis; D002196:Capillaries / Q000473:pathology; D002470:Cell Survival; D017690:Cell Transplantation; D006321:Heart / Q000503:physiopathology*; D006334:Heart Function Tests; D016027:Heart Transplantation; D021621:Imaging, Three-Dimensional; D007150:Immunohistochemistry; D019012:Integrin beta1 / Q000378:metabolism; D008163:Luminescent Measurements; D017202:Myocardial Ischemia / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000637:transplantation*; D051381:Rats; D011916:Rats, Inbred F344; D011917:Rats, Inbred Lew
chemical_list: D019012:Integrin beta1