Regeneration of infarcted myocardium by intramyocardial implantation of ex vivo transforming growth factor-beta-preprogrammed bone marrow stem cells.
BACKGROUND
Recent studies have shown that bone marrow-derived stem cells differentiate into the phenotype of cardiomyocytes in vivo and in vitro. We tried to regenerate infarcted myocardium by implanting ex vivo transforming growth factor (TGF)-beta-preprogrammed CD117 (c-kit)-positive (CD117+) stem cells intramyocardially.


RESULTS
CD117+ cells were isolated from the bone marrow mononuclear cells of GFP-transgenic or normal C57/BL6 mice. The myogenic differentiation of CD117+ cells was achieved by cultivation with TGF-beta. Using an acute myocardial infarction model, we also tried to regenerate infarcted myocardium by implanting untreated (newly isolated) or preprogrammed (24 hours of cultivation with 5 ng/mL TGF-beta1) CD117+ cells intramyocardially. TGF-beta increased the cellular expression of myosin, troponins, connexin-43, GATA-4, and NKx-2.5, which suggested that it induced the myogenic differentiation of CD117+ cells. Compared with the effects of PBS injection only, the microvessel density in the infarcted myocardium was increased significantly 3 months after the implantation of either TGF-beta-preprogrammed or untreated CD117+ cells. Moreover, many of the TGF-beta-preprogrammed CD117+ cells were stained positively for myosin, whereas few of the untreated CD117+ cells were. Histological analysis revealed newly regenerated myocardium in the left ventricular anterior wall after the implantation of TGF-beta-preprogrammed cells but not untreated cells. Furthermore, the left ventricular percent fraction shortening was significantly higher after the implantation of TGF-beta-preprogrammed cells than after the implantation of untreated CD117+ cells.


CONCLUSIONS
TGF-beta conducted the myogenic differentiation of CD117+ stem cells by upregulating GATA-4 and NKx-2.5 expression. Therefore, the intramyocardial implantation of TGF-beta-preprogrammed CD117+ cells effectively assisted the myocardial regeneration and induced therapeutic angiogenesis, contributing to functional cardiac regeneration.
Li
Tao-Sheng
TS
Division of Cardiovascular Surgery, Department of Medical Bioregulation, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan.
Hayashi
Masanori
M
Ito
Hiroshi
H
Furutani
Akira
A
Murata
Tomoaki
T
Matsuzaki
Masunori
M
Hamano
Kimikazu
K
D000818:Animals; D001854:Bone Marrow Cells; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D050991:GATA4 Transcription Factor / Q000235:genetics; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009203:Myocardial Infarction / Q000473:pathology* / Q000628:therapy*; D032383:Myocytes, Cardiac / Q000166:cytology*; D018919:Neovascularization, Physiologic / Q000187:drug effects; D019009:Proto-Oncogene Proteins c-kit; D012038:Regeneration / Q000187:drug effects*; D014157:Transcription Factors / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects
D050991:GATA4 Transcription Factor; C484171:Gata4 protein, mouse; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; C484469:Nkx2-5 protein, mouse; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D019009:Proto-Oncogene Proteins c-kit