Remodeling of muscular component of the myocardial tissue depending on age, sex and cause of death.

AIM: Ageing process, as well as different pathological conditions, can induce morphological and functional changes in all tissue including those of cardiovascular system and particularly in myocardial tissue. The authors realized a quantitative preliminary study of the main component of the myocardium, the specific muscle cells. PATIENTS, MATERIALS AND METHODS: Samples of myocardial tissue with no evident lesion coming from 95 patients deceased in hospital and autopsied were histologically processed and proportion of myocardial specific cells (myocardial fibers; MF) was assessed, on virtual slides, with a specially built computer program. For statistical comparison of data Pearson's correlation test was used. RESULTS: The MF proportion had the smallest values in childhood and adolescence They significantly increased during young adulthood and then decreased discretely until the elderly period of life. The MF proportion had the highest values in the left ventricle wall (LV_W) from where it fell towards the interventricular septum (IVS) and had the lowest levels in the right ventricle wall (RV_W), in all main life periods, excepting the first one (childhood and adolescence), where it had the highest values in the RV_W. MF proportion has also high levels in males than in females in all main regions of cardiac wall. Also, their decrease from the LV_W to RV_W is more pronounced in females than in males. Related to the cause of death, the MF proportion had the lowest values in vascular conditions causing death (V_P), then, they increased significantly in non-vascular conditions causing death (NV_P) and they decreased slightly in sudden∕violent deaths (S∕V_Dths). In NV_P and S∕V_Dths, MF proportion had the highest values in LV_W, then they decreased towards IVS and, finally, in RV_W. In V_P, in turn, MF proportion had the highest values in LV_W and the lowest ones in IVS. In the LV_W of NV_P and S∕V_Dths groups, MF proportion values decreased from anterior to posterior cardiac wall regions whereas, in V_P group, they were almost the same in all main regions. MF proportion had a decreasing trend from left to right main cardiac wall regions, both in men and women. However, in men, the highest values were in NV_P group and the lowest, in S∕V_Dths group, and, in women, the highest values were in S∕V_Dths group and lowest in V_P group. CONCLUSIONS: The myocardial muscle cell compartment showed a decreasing pattern along all regions of the heart wall with age, both in men and women with higher values in former. Regarding the causes of death, the remodeling trend was the same from anterior to posterior regions of the heart wall, but with marked differences between the two sexes and the ranking of proportion values between the defined groups of causes of death.