Neuroinflammation: An Integrating Overview of Reactive-Neuroimmune Cell Interactions in Health and Disease

Abstract

The concept of central nervous system (CNS) inflammation has evolved over the last decades. Neuroinflammation is the response of reactive CNS components to altered homeostasis, regardless of the cause to be endogenous or exogenous. Neurological diseases, whether traumatic, neoplastic, ischemic, metabolic, toxic, infectious, autoimmune, developmental, or degenerative, involve direct and indirect immune-related neuroinflammation. Brain infiltrates of the innate and adaptive immune system cells appear in response to an infective or otherwise noxious agent and produce inflammatory mediators. Mediators of inflammation include local and recruited cells and signals. Processes derived from extrinsic and intrinsic CNS diseases also elicit the CNS inflammatory response. A deeper understanding of immune-related inflammation in health and disease is necessary to find potential therapeutic targets for preventing or reducing CNS damage. This review is aimed at discussing the innate and adaptive immune system functions and their roles in regulating brain cell responses in disease and homeostasis maintenance.

The Health Hazards of Volcanoes: First Evidence of Neuroinflammation in the Hippocampus of Mice Exposed to Active Volcanic Surroundings

“…They help maintain the homeostasis of the brain environment under normal conditions but show a strong reaction in response to adverse conditions, becoming activated microglia and adopting an amoeboid phenotype. These microglia proliferate and migrate to the site of injury or damage, where they perform a protective function, removing cellular debris [ 75 – 77 ]. On the other hand, overactivation of microglia, with excess production of inflammatory mediators, can have neurotoxic consequences.…”

Immunologic and Neuroinflammatory Bases of Epileptogenesis: Personalized Therapeutic Options

“…The innate immune system provides a general first-line defense in a non-specific manner, mainly through natural killer cells and phagocytes, but their role within the CNS is poorly defined. However, their equivalent in the CNS is the microglia, which is also considered to play a role in the pathogenesis of several neurological disorders [8].…”

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“…Due to the high metabolic rate, oligodendrocytes are much more sensitive to oxidative stress [229]. Furthermore, they are highly vulnerable to the neuroinflammation produced by cytokines released by microglia [234]. Oligodendrocytes also participate in the immune response as they can act as antigen-presenting cells, leading to the activation of CD8+ T cells [235].…”

“…Oligodendrocytes also participate in the immune response as they can act as antigen-presenting cells, leading to the activation of CD8+ T cells [235]. They can also release inflammatory mediators resulting in microglia activation and express cytokine receptors, promoting microglial recruitment to damage sites [234]. Remarkably, blockade of LPS-stimulated pro-inflammatory molecules decreases oligondendrocytic loss and reduces WM impairment [236].…”