GENDER DIFFERENCES AND AGING - EFFECTS ON THE HUMAN HEART

Objectives. This study investigated the changes in myocyte size and nu mber in the left and right ventricles that occur with aging in the fem ale and male heart. Background. Differences in life span between women and men may be related to a better preservation of myocardial structu re in the female heart with aging, On this basis, the hypothesis was a dvanced that the aging process has a different impact on the integrity of the myocardium in the two genders. Methods. Morphometric methodolo gies were applied to analyze the changes in number and size of ventric ular myocytes in the hearts of 53 women and 53 men. The changes in mon onucleated and binucleated myocytes with age were determined in enzyma tically dissociated cells. The age interval examined varied from 17 to 95 years. Results. Aging was associated with a preservation of ventri cular myocardial mass, aggregate number of mononucleated and binucleat ed myocytes, average cell diameter and volume in the female heart, In contrast, nearly 1 g/year of myocardium was lost in the male heart, an d this phenomenon accounted for the loss of similar to 64 million cell s. This detrimental effect involved the left and right sides of the he art, In the remaining cells, myocyte cell volume increased at a rate o f 158 mu m(3)/year in the left and 167 mu m(3)/year in the right ventr icle. Conclusions. Aging does not lead to myocyte cell loss and myocyt e cellular reactive hypertrophy in women, indicating that gender diffe rences may play a significant role in the detrimental effects of the a ging process on the heart.