About this Research Topic
For a long time, the study of the brain has largely focused on neuronal cells. However, neurons develop and interact closely together in space and time with the neuroglia, represented by astrocytes, microglia, and oligodendrocytes. Glia are further highly conserved throughout evolution and are, except for the cerebellum, the most abundant cell type in almost all subregions of the mammalian brain. This suggests important functional roles for glia and their interactions with neurons in both brain physiology and pathology. Many models for studying neurons and glia have been based on rodents, where lines of identical animals are available and genetic manipulations are easily accomplished. However, model validity, compared to the human brain, remains to be confirmed. Indeed, recent studies revealed several important differences between rodent and human neurons and glia in terms of morphology, receptor composition, inflammatory responses, and released mediators. Despite these differences, rodent models have helped to understand the roles of glial cells in neuronal pathologies, including Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, glioblastoma, autism, and psychiatric disorders. Hopes that animal models would lead to new medicaments have however often been muted by poor progress from successful pre-clinical tests, leading to an absence of efficacy in clinical trials.
In order to bridge this gap between animal and human studies, three classes of brain surrogates offer researchers a way to investigate how the living human brain works, without the need for procedures in people: (1) organoids, (2) ex vivo brain tissues, and (3) chimaeras. The main source of human fresh brain tissue is nowadays from operations on patients with conditions such as epilepsies and brain tumors. The possibility to obtain these fresh tissues is not rare, considering the high number of brain surgeries per year. Moreover, technological advances, including imaging and the techniques used to preserve the functional properties of brain tissues in the lab, could make these approaches considerably more powerful for the investigation of neuron-glia-interactions across various pathological conditions.
This Research Topic welcomes papers using or discussing the use of human brain tissue, post mortem or fresh, for organoids, ex vivo, and chimaeras studies that pertain to neuronal and glial cell functions and interactions in neuropathological contexts. The aim is to sensitize researchers to consider and integrate, in their research work on neurons and glia, the use of human brain tissue. This effort could tremendously improve our understanding of brain pathology and reveal unexpected differences between human and animal brain function. This effort could also offer a practical alternative, reducing some of the already used animal models, answering to the worldwide directive to reduce and replace them as much as possible. This Research Topic also welcomes papers about the challenges associated with human studies (e.g. inter-individual variability, comorbidities, lifestyle factors) and the ethical considerations related to the use of human tissue and the reduction of animal use in the neuroscience field.
Keywords: Neuro-glia interactions, Brain pathologies, Human brain models, Animal model replacements, Ethics
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