AGING, CARDIAC-HYPERTROPHY AND ISCHEMIC CARDIOMYOPATHY DO NOT AFFECT THE PROPORTION OF MONONUCLEATED AND MULTINUCLEATED MYOCYTES IN THE HUMAN HEART

The current investigation was designed to evaluate whether the proport ion of mononucleated binucleated, trinucleated and tetranucleated myoc ytes varies in the left ventricle, interventricular septum and right v entricular free wall with aging, cardiac hypertrophy and ischemic card iomyopathy, In addition, the number and dimensional properties of myoc ytes were measured to determine whether a relationship existed between myocyte size and number, and organ hypertrophy. For this purpose, 72 normal hearts were obtained from individuals who died from causes othe r than cardiovascular disease and compared with 81 hypertrophied heart s and 95 with ischemic cardiomyopathy. The age interval examined varie d from 26 to 93 years. The analysis of enzymatically dissociated myocy tes in control left ventricles demonstrated that mononucleated, binucl eated, trinucleated and tetranucleated myocytes comprised 74%, 25.5%, 0.4% and 0.1% of the entire myocyte population, Similarly, mononucleat ed myocytes constituted the prevailing cell population of the interven tricular septum and right ventricular free wall, Aging, myocardial hyp ertrophy and ischemic cardiomyopathy did not change the percentages of mononucleated and multinucleated myocyte in the ventricular myocardiu m. Cardiac hypertrophy and ischemic cardiomyopathy were characterized by comparable increases in myocyte size in spite of a significant diff erence in the magnitude of myocardial hypertrophy. Myocyte number was increased in hypertrophied hearts, whereas myocyte cell loss occurred in ischemic cardiomyopathy. In conclusion, aging, cardiac hypertrophy and ischemic cardiomyopathy do not alter the fractions of mononucleate d and multinucleated myocytes in the myocardium. (C) 1996 Academic Pre ss Limited.