OBJECTIVES: This study investigated the changes in myocyte size and number in the
left and right ventricles that occur with aging in the female and male heart.
BACKGROUND: Differences in life span between women and men may be related to a
better preservation of myocardial structure in the female heart with aging. On
this basis, the hypothesis was advanced that the aging process has a different
impact on the integrity of the myocardium in the two genders.
METHODS: Morphometric methodologies were applied to analyze the changes in number
and size of ventricular myocytes in the hearts of 53 women and 53 men. The
changes in mononucleated and binucleated myocytes with age were determined in
enzymatically dissociated cells. The age interval examined varied from 17 to 95
years.
RESULTS: Aging was associated with a preservation of ventricular myocardial mass,
aggregate number of mononucleated and binucleated myocytes, average cell diameter
and volume in the female heart. In contrast, nearly 1 g/year of myocardium was
lost in the male heart, and this phenomenon accounted for the loss of
approximately 64 million cells. This detrimental effect involved the left and
right sides of the heart. In the remaining cells, myocyte cell volume increased
at a rate of 158 microns3/year in the left and 167 microns3/year in the right
ventricle.
CONCLUSIONS: Aging does not lead to myocyte cell loss and myocyte cellular
reactive hypertrophy in women, indicating that gender differences may play a
significant role in the detrimental effects of the aging process on the hear
