Parahippocampal corpora amylacea and neuronal lipofuscin in human aging

The aim of this research was to quantify the number of corpora amylacea and lipofuscin-bearing neurons in the parahippocampal region of the brain. Right parahippocampal gyrus specimens of 30 cadavers were used as material for histological and morphometric analyses. A combined Alcian Blue and Periodic Acid-Schiff technique was used for identification and quantification of corpora amylacea and lipofuscin-bearing neurons. Immunohistochemistry was performed using S100 polyclonal, neuron-specific enolase and glial fibrillary acidic protein monoclonal antibodies for differentiation of corpora amylacea and other spherical inclusions of the aging brain. Cluster analysis of obtained data showed the presence of three age groups (median age: I = 41.5, II = 68, III = 71.5). The second group was characterized by a significantly higher numerical density of subcortical corpora amylacea and number of lipofuscin-bearing neurons than other two groups. Values of the latter cited parameters in the third group were insignificantly higher than the first younger group. Linear regression showed that number of parahippocampal lipofuscin-bearing neurons significantly predicts numerical density of subcortical corpora amylacea. The above results suggest that more numerous parahippocampal region corpora amylacea and lipofuscin-bearing neurons in some older cases might represent signs of its’ neurons quantitatively-altered metabolism.