title: [STEM CELLS PLAY NO CONSIDERABLE ROLE IN CARDIOMYOCYTE REPOPULATION OF ADULT HUMAN HEART].
abstract: There are two viewpoints concerning cardiac regeneration. One assumes that the myocardium of an adult human heart has a weak regenerative capacity. According to another, myocardium can renew at a high rate due to the presence of resident stem cells. This study was aimed to test the role of stem cells in myocardium repopulation in adult humans of different age by examining the distribution of cardiomyocytes as to their size and ploidy. Cytofluorimetry and interferometry were used to determine the dry weight, volume and ploidy of myocytes isolated from the left ventricle of the normal heart of 12 men aged 20-30 years (n = 7) and 40-50 years (n = 5). Dry weight of cardiomyocytes made up 6906 ± 182 pg (10(-12) g) aged 20-30 years and 9126 ± 263 pg in men aged 40-50 years. There were no cells with an intermediate volume between amplifying and mature myocytes. The number of candiomyocytes in the left ventricle made up (3.18 ± 0.05) x 10(9) cells in the age group 20-30 years and (2.06 ± 0.6) x 10(9) cells in the age group 40-50 years. Most of the myocyte population was represented by mononucleate cells with tetraploid nuclei (41.3%). Proportion of myocytes of different ploidy classes did not change in the interval from 20 to 50 years. Our results strongly suggest that stem cells of the heart are not involved in the regeneration of human myocardium during aging. The function of the aging heart is mostly compensated by the hypertrophy of the remaining myocytes.
authors.forename: E V
authors.initials: EV
authors.lastname: Baidyuk
authors.forename: A Ya
authors.initials: AY
authors.lastname: Gudkova
authors.forename: G A
authors.initials: GA
authors.lastname: Sakuta
authors.forename: E N
authors.initials: EN
authors.lastname: Semernin
authors.forename: A V
authors.initials: AV
authors.lastname: Stepanov
authors.forename: B N
authors.initials: BN
authors.lastname: Kudryavtsev
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology*; D002452:Cell Count; D002467:Cell Nucleus / Q000235:genetics* / Q000648:ultrastructure; D048429:Cell Size; D006352:Heart Ventricles / Q000166:cytology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000166:cytology; D032383:Myocytes, Cardiac / Q000502:physiology* / Q000648:ultrastructure; D011003:Ploidies; D012038:Regeneration / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology