Dendritic pathology in AD

What is it about?

Dendritic pathology and decrease of dendritic spine density are prominent phenomena in early cases of Alzheimer's disease, which correlate significantly with the progressive decline of the mental faculties. In previous studies we have described the pathological alterations of the dendrites and the dendritic spines in the prefrontal area of the cortex and the cerebellum. In this study we attempted to describe the morphological alterations of the dendrites and the dendritic spines, quantifying them in the acoustic and the visual cortices of eleven cases of Alzheimer's disease, applying Golgi staining and electron microscopy. In addition, describing also the ultrastructural changes of the mitochondria in the dendritic profiles and the dendritic spines we noticed that mitochondrial pathology correlates substantially with the dystrophic dendrites, the loss of dendritic branches and the pathological alteration of the dendritic spines. We would hypothesize that mitochondrial alterations may play a very important role in dendritic degeneration and the loss of dendritic spines and we should have thought that therapeutic strategies protecting the mitochondria may be beneficial in Alzheimer's disease.

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Why is it important?

Large number of neurons in the acoustic and visual cortices in Alzheimer's brains demonstrated dendritic varicosities and distorted spine shapes. The majority of the varicosities contained abnormal polymorphous elongated mitochondria. In a substantial number of neurons in the fifth layer of the acoustic and visual cortices some axonless or unattached spines were seen protruded from the secondary dendritic branches of the apical dendrite. The spinal density, which was estimated also at the ultrastructural level, was dramatically reduced as compared with normal controls

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