ackground : During the development of the cardiac hypertrophy, cytoplasmic contents of cardiac myocyte usually increase, but the changes in the nucleus of myocytes are not well understood. Therefore, we used flow cytometry to study the changes of
nuclear DNA in cardiac hypertrophy from human autopsy heart tissue. Besides, we also tried to see the DNA ploidy of developing heart of fetus.
Method : Nine hypertrophied human hearts ranging from 350-620g (Group Ⅱ: 350-500g,
Group Ⅲ: >500g) and 9 control hearts (Group Ⅰ: 250-350g) which we could obtain after the
legal autopsy were studied with flow cytometric analysis. And 3 fetal hearts of 20-24
gestational weeks (Group Ⅳ) were also studied. Nuclear DNA was analyzed with FACScan
(Becton-Dickinson Co.) after tissue preparation using Modified Hedley and Vindelov Method
and staining with Krishan staining buffer.
Results : In control hearts (GroupⅠ). Flow cytometric analysis showed normal Diploidy
pattern in all tissue. However, in cardiac hypertrophy, Non-Diploidy pattern was predominant
(3 out of 5 specimen in Group Ⅱ, and all 4 specimen in Group Ⅲ) and Tetraploidy was
usually observed in this abnormal ploidy pattern, but Aneuploidy was also seen in 2 cases
of severe hypertrophy of Group Ⅲ. Proliferative indexes increased progressively in Group I,
Ⅱ, and Ⅲ (17.8±5.5%, 24.8±7.4%, and 36.4±5.2%, respectively) (p<0.05 between Group Ⅰ
and Ⅱ, and p<0.01 between Group I & Ⅲ). Normal growing heart tissue of fetus showed
normal Diploidy pattern.
Conclusions : In cardiac hypertrophy, abnormal nuclear DNA ploidy pattern can be
observed. This finding might say that, during the genesis of cardiac hypertrophy, not only
cytoplasmic change but also DNA synthesis in the nucleus occurs, but G2 phase arrest
happens without further mitosis.
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