title: Exercise-induced physiological hypertrophy initiates activation of cardiac progenitor cells.
abstract: OBJECTIVE
  Physiological hypertrophy is featured by the hypertrophy of pre-existing cardiomyocytes and the formation of new cardiomyocytes. C-kit positive cardiac progenitor cells increased their numbers in exercise-induced physiological hypertrophy. However, the participation of Sca-1 positive cells in the physiological adaptation of the heart to exercise training is unclear.
  
  
  METHODS
  Physiological hypertrophy was induced by swimming and the mRNA levels of GATA binding protein 4 (GATA4), atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), endogenous hepatocyte growth factor (HGF), and insulin like growth factor-1 (IGF-1) from the whole heart were determined by real-time polymerase chain reactions (RT-PCRs) analysis. Immunofluorescent staining was used to compare the number of C-kit and Sca-1 positive cardiac progenitor cells. In addition, mRNA levels of C-kit and Sca-1 in left ventricle (LV), right ventricle (RV), and outflow tract (OFT) were determined in mice swimming for 7, 14, and 21 days by RT-PCRs.
  
  
  RESULTS
  The ratio of heart weight (HW) to body weight and HW to tibia length and the mRNA level of GATA4 were increased while mRNA levels of ANP and BNP remained unchanged. C-kit and Sca-1 positive cardiac progenitor cells were activated by swimming training. An increased endogenous production of HGF and IGF was observed at least at the mRNA level. Swimming induced a significant up-regulation of C-kit in LV of mice swimming for 1, 2 and 3 weeks and in RV of mice swimming for 3 weeks. Sca-1 positive cardiac progenitor cells were increased in LV and OFT in mice swimming for 3 weeks.
  
  
  CONCLUSIONS
  This study presents that swimming-induced physiological hypertrophy initiates activation of cardiac progenitor cells.
authors.affiliation: Regeneration Lab and Experimental Center of Life Sciences, School of Life Science, Shanghai University Shanghai 200444, China ; Innovative Drug Research Center of Shanghai University Shanghai 200444, China ; Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University Shanghai 200444, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Xiao
authors.affiliation: Regeneration Lab and Experimental Center of Life Sciences, School of Life Science, Shanghai University Shanghai 200444, China ; Innovative Drug Research Center of Shanghai University Shanghai 200444, China.
authors.forename: Tianzhao
authors.initials: T
authors.lastname: Xu
authors.affiliation: Regeneration Lab and Experimental Center of Life Sciences, School of Life Science, Shanghai University Shanghai 200444, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.affiliation: Regeneration Lab and Experimental Center of Life Sciences, School of Life Science, Shanghai University Shanghai 200444, China.
authors.forename: Dongcao
authors.initials: D
authors.lastname: Lv
authors.affiliation: Regeneration Lab and Experimental Center of Life Sciences, School of Life Science, Shanghai University Shanghai 200444, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Chen
authors.affiliation: Regeneration Lab and Experimental Center of Life Sciences, School of Life Science, Shanghai University Shanghai 200444, China.
authors.forename: Qiulian
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Cardiology, Shanghai Tongji Hospital, Tongji University School of Medicine Shanghai 200065, China.
authors.forename: Jiahong
authors.initials: J
authors.lastname: Xu
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D000950:Antigens, Ly / Q000235:genetics / Q000378:metabolism; D009320:Atrial Natriuretic Factor / Q000235:genetics / Q000378:metabolism; D059267:Cardiomegaly, Exercise-Induced; D050991:GATA4 Transcription Factor / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D017228:Hepatocyte Growth Factor / Q000235:genetics / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000502:physiology*; D020097:Natriuretic Peptide, Brain / Q000235:genetics / Q000378:metabolism; D010805:Physical Conditioning, Animal; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism / Q000502:physiology*; D013550:Swimming; D013997:Time Factors; D020257:Ventricular Remodeling
chemical_list: D000950:Antigens, Ly; D050991:GATA4 Transcription Factor; C484171:Gata4 protein, mouse; C553307:HGF protein, mouse; C074650:Ly6a protein, mouse; D008565:Membrane Proteins; D012333:RNA, Messenger; C519530:insulin-like growth factor-1, mouse; D020097:Natriuretic Peptide, Brain; D017228:Hepatocyte Growth Factor; D007334:Insulin-Like Growth Factor I; D009320:Atrial Natriuretic Factor; D019009:Proto-Oncogene Proteins c-kit
keywords: Exercise; cardiac progenitor cells; hypertrophy; physiological