The Influence of Ageing, Sex and Cause of Death on the Myocardial Tissue Collagen Fibrillary Component Behaviour

The morphology and the function of human body are influenced by two main factors: the passing of the years and the increasing diversity of diseases with their subsequent lesions. The morphological structures of the heart are not exempt from the synergistic influence of these two major factors. The authors' goal was to compare the variations of interstitial mature collagen fibers (COLF) amount-% between the different main regions of the heart wall during patients´ ageing, on one hand, and, depending on patients' cause of death, on the other hand.

Samples of myocardial tissue with no evident lesion, coming from 95 patients with different ages (0-24 years-AP_01, 25-44 years-AP_02, 45-64 years-AP_03 and >64 years-AP_04) deceased in hospital with different causes of death (vascular diseases-V_P, non-vascular diseases-NV_P, and suspect/violent cause of death-S/V_Dth) and autopsied, were collected from five epicardium-to-endocardium cross sections (left ventricle anterior wall-LV_AW, lateral wall-LV_LW and posterior wall-LV_PW, interventricular septum-IVS and right ventricle wall-RVW). Further, they were histologically processed and stained with Picro Syrius Red technique. COLF proportion was assessed, on virtual slides, with a a computer program designed specifically for this purpose. For statistical comparison of data, Kruskal-Wallis and Pearson correlation tests were used.

The COLF proportion had the smallest values in elderly and they increased markedly towards the younger periods of age. Then, the COLF proportion had the highest values in the RV_W (excepting the AP_04 period of life), and the lowest values in the IVS. In LV_W, COLF proportion had a general increasing trend from anterior to posterior regions in AP_01 and AP_03 periods of life and in males. In turn, it had decreasing trend from anterior to posterior regions in AP_02 and AP_04 periods of life and in females. The COLF proportion had the highest values in NV_P group in all cardiac main regions and the lowest values in V_P group (excepting LV), in both men and women. It had also the highest values in the RV_W and the lowest ones in IVS in all three diseases groups. In LV, COLF proportion had the highest values in NV_P group but the smallest ones in S-V_Dth group, in all main heart regions of this group. The COLF proportion had higher values in males than in females in all heart wall main regions in NV_P group and S-V_Dth group but vice versa in V_P group.