Three-Dimensional Nuclear Size and DNA Content in Hypertensive Heart Disease

Cardiac myocyte hypertrophy is commonly observed histologically in the hypertensive heart. Hypertrophic nuclei of myocytes are also detected in myocardial tissue. However, it is not clear whether an increase of nuclear size in myocytes indicates high DNA synthesis in hypertensive hearts. A total of 20 human hearts obtained at autopsy were studied. Following preparation of the hearts, the myocardium was weighed and total DNA content was determined biochemically. The DNA content was calculated by flow cytometry, and the structural changes of myocyte nuclei were visualized by three-dimensional (3-D) reconstruction. The percentage of myocytes in the G2M phase of the cell cycle was significandy increased in hypertensive hearts, compared with control hearts. The number of S-phase myocytes in hypertensive hearts was approximately twice that in control hearts. The 3-D myocardial nuclear size was bigger in hypertensive hearts than in control hearts. In conclusion, there were no dramatic changes of the DNA content and 3-D nuclear size, and such changes depended on remodeling of the intranuclear matrix in hypertrophic myocytes.