Iron Deposition in Cerebrovascular Diseases: A Post-Mortem Review

Abstract

Introduction In the central nervous system, iron (Fe) linked to proteins, is involved in many important processes such as oxygen transportation, oxidative phosphorylation, and synthesis and metabolism of neurotransmitters [1]. Astrocytes are largely responsible for distributing Fe in the normal brain. As capillary endothelial cells are separated from the neuropil by the end-feet’s of astrocytes, they are ideally positioned to transport Fe to other brain cells [2]. The highest concentrations of Fe in the normal cerebral hemispheres are found in the globus pallidus, followed by the putamen, the caudate nucleus and the thalamus on the transverse relaxation rates R2 and R2* magnetic resonance imaging (MRI) [3]. In the substantia nigra the main high Fe compound in dopamine and norepinephrine neurons is the neuromelanin-iron complex that serves to trap Fe and to provide neuronal protection for oxidative stress [4]. The Fe concentration is lower in infant brains compared to adult ones [5]. It increases during the further aging process in the different human brain regions, but most strongly in the basal ganglia [6-7]. The Fe content decreases after the age of 80 years [8]. This is probably due to progressive age-related neurodegenerative changes [9].