title: Cardiomyocytes undergo cells division following myocardial infarction is a spatially and temporally restricted event in rats.
abstract: Dividing cardiomyocytes are observed in autopsied human hearts following recent myocardial infarction, however there is a lack of information in the literature on the division of these cells. In this study we used a rat model to investigate how and when adult mammalian cardiomyocytes proliferate by cell division after myocardial infarction. Myocardial infarction was induced in Wistar rats by ligation of the left coronary artery. The rats were sacrificed periodically up to 28 days following induced myocardial infarction, and the hearts subjected to microscopic investigation. Cardiomyocytes entering the cell cycle were assayed by observation of nuclear morphology and measuring expression of Ki-67, a proliferating cell marker. Ki-67 positive cardiomyocytes and dividing nuclei were observed initially after 1 day. After 2 days dividing cells gradually increased in number at the ischemic border zone, reaching a peak increase of 1.12% after 3 days, then gradually decreasing in number. Dividing nuclei increased at the ischemic border zone after 3 days, peaked by 0.14% at day 5, and then decreased. In contrast, Ki-67 positive cells and dividing nuclei were limited in number in the non-ischemic area throughout all experiments. In conclusion, mitogenic cardiomyocytes are present in the adult rat heart following myocardial infarction, but were spatially and temporally restricted.
authors.affiliation: Cardiopulmonary Division, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Yuasa
authors.forename: Keiichi
authors.initials: K
authors.lastname: Fukuda
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Tomita
authors.forename: Jun
authors.initials: J
authors.lastname: Fujita
authors.forename: Masaki
authors.initials: M
authors.lastname: Ieda
authors.forename: Satoko
authors.initials: S
authors.lastname: Tahara
authors.forename: Yuji
authors.initials: Y
authors.lastname: Itabashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Yagi
authors.forename: Haruko
authors.initials: H
authors.lastname: Kawaguchi
authors.forename: Yasuyo
authors.initials: Y
authors.lastname: Hisaka
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ogawa
mesh_terms: D000818:Animals; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D019394:Ki-67 Antigen