Astrocytes in rare neurological conditions: Morphological and functional considerations

Abstract

Astrocytes are a population of central nervous system (CNS) cells with distinctive morphological and functional characteristics that differ within specific areas of the brain and are widely distributed throughout the CNS. There are mainly two types of astrocytes, protoplasmic and fibrous, which differ in morphologic appearance and location. Astrocytes are important cells of the CNS that not only provide structural support, but also modulate synaptic activity, regulate neuroinflammatory responses, maintain the blood–brain barrier, and supply energy to neurons. As a result, astrocytic disruption can lead to widespread detrimental effects and can contribute to the pathophysiology of several neurological conditions. The characteristics of astrocytes in more common neuropathologies such as Alzheimer's and Parkinson's disease have significantly been described and continue to be widely studied. However, there still exist numerous rare neurological conditions in which astrocytic involvement is unknown and needs to be explored. Accordingly, this review will summarize functional and morphological changes of astrocytes in various rare neurological conditions based on current knowledge thus far and highlight remaining neuropathologies where astrocytic involvement has yet to be investigated.

Effects and Mechanisms of Exosomes from Different Sources in Cerebral Ischemia

“…Their unique morphology can provide structural support to neurons. Furthermore, astrocytes have other functions, such as regulating neuroinflammatory responses, modulating synaptic activity, supplying energy to neurons, and maintaining the blood–brain barrier (BBB) [ 47 ]. Astrocytes also play a part in regulating autophagy level after brain injury occurs.…”

Nuclear Factor Erythroid-2-Related Factor 2 Signaling in the Neuropathophysiology of Inherited Metabolic Disorders

“…Since Nrf2 signaling pathway plays an important role in the redox regulatory system between astrocytes and neurons and oxidative stress is commonly observed as a pathomechanism in many IMDs ( Mc Guire et al, 2009 ; Ribas et al, 2014 ; Grings et al, 2020 ; Wajner et al, 2020 ; Ravi et al, 2021 ), it is conceivable that alterations in Nrf2 expression are involved in the pathophysiology of neurometabolic disorders, representing a promising target for the development of novel therapies that may improve the quality of life of patients.…”

Critical Involvement of Glial Cells in Manganese Neurotoxicity

“…The best-characterized functions of these cells are the turnover of neurotransmitters, ion homeostasis, as a constituent of the neurovascular unit, synaptogenesis, neuronal remodeling, and so on [ 18 ]. Astrocytes can be classified at least into two main categories regarding their localization and morphology: fibrous in the white matter with a clear star shape, and protoplasmic in the grey matter with a more plain appearance [ 27 ]. Furthermore, astrocytes oversee and protect neurons from neurotoxic insults elicited by heavy metals, which makes them the primary target of heavy metal toxicity [ 28 ].…”