SIGNIFICANCE OF THE DNA-SYNTHESIS IN HYPERTROPHIC CARDIOMYOPATHIES

DNA content and proliferating cell nuclear antigen (PCNA) expression w ere investigated in normal hearts, in hypertrophic from hemodynamic ov erload hearts and in hypertrophic cardiomyopathy (HCM). The aim of thi s study was mainly to determine whether the hyperdiploid myocardial ce lls in all cases are in dynamic or static phase. The percentage of PCN A positive cells only in the HCM group was significantly higher (mean value = 25.4 %) than the percentage of hyperdiploid cells (mean value = 9.3 %). Therefore, the DNA replication occurs through a different pr ocess from that of normal cell cycle which lead to an increase in ploi dy and eventually mitosis. These data should be interpreted not only a s the result of a periodic amitotic DNA renewal and not even as the re sult of an increased apoptosis, but especially as a repair process of the DNA molecules affected by a various types of damages in HCMs.