Morfometrijske i imunohistohemijske karakteristike parahipokampalne kore velikog mozga čoveka tokom procesa starenja

Abstract

Aging of the parahippocampal cortex is accompanied by reduction of its volume or thickness, which is commonly associated with loss and changes of nerve cells. The most common changes include cell number reduction, deposition of lipofuscin, formation of corpora amylacea in astrocytes, and reduction of cortex vascularization, which may represent the basis for the development of cognitive dysfunction. Endothelium of blood vessels is the place where first changes occur, which eventually results in disruption of haematoencephalic barrier and amyloid deposition originating from the circulation both within their walls, and in the brain parenchyma. These changes may represent not only an integrative part of normal aging, but occur within neurodegenerative disorders, as well, Alzheimer's dementia, in particular. The aim of this research was to carry out quantification of structural changes in different cortical layers (subpial, subcortical, lamina II-V) on human parahippocampal cortex tissue obtained from autopsies without previous diagnosis of diseases of the nervous system, using histochemical, immunohistochemical and morphometric methods, as well as determine neurone deficit, proliferation of glial cells and the existence of structures known as corpora amylacea using immunohistochemical methods (NSE, GFAP, S100). The research has shown that during normal aging, in parahippocampal cortex there occurs increase in the number of corpora amylacea localized in subpial region that is even higher in subcortical white matter, with no significant change in the size and shape. Positive reaction to NSE, determined by immunohistochemical methods, probably indicates the presence of neural components, while a weaker reaction to GFAP and positive reaction to S100 protein indicates that corpora amylacea are likely to be astrocyte inclusions. The number of nerve cells with deposits of lipofuscin of the examined samples increases significantly with age. The results in the obtained age groups indicate that number of neurons and astrocytes in parahippocamplal cortex is balanced and their relationship does not significantly change during the aging process. Interrelationship between the obtained results suggests that the presence of above mentioned structural changes may lead to damage of those brain structures that are responsible for normal memory function and thus responsible for the cognitive changes present in healthy elderly persons.