Chapters authored
Immune-Mediated Inflammation: Human T CD4 Helper Lymphocyte Diversity and Plasticity in Health and Disease
The CD4+ T helper (Th) cells have a critical role in organizing the adaptive immune response. The emerging cells of the differentiation after the immune synapse produce helper T cell subpopulations that activate, suppress, or regulate the immune response upon interaction with varying immune cells. There are two main Th cell functional categories: the “effector cells” and the “regulatory T cells.” Classic T helper lymphocytes can also be distinguished by their lineage according to the developmental microenvironment, the expression of cell adhesion-homing receptors, the profile of cytokines they are exposed to, and the involved transcription factors. Traditionally, the CD4+ and CD8+ phenotypes have been considered as helper and cytotoxic/suppressor T lymphocytes, respectively. Currently, the distinction is little rigorous. The immune response is exceedingly complex beyond the classic Th1 and Th2 effector cells’ involvement, and other populations of helper T lymphocytes like the Th17, Tfh, Th22, and Th9 lymphocytes have been phenotypically characterized. These lymphocytes also participate in the pathogenesis of several immune-mediated inflammatory disorders. Here, we revisit and discuss the essential aspects of the state of the art regarding phenotypic diversity and plasticity of TCD4 cells in the T lymphocyte repertoire frame and their potential implication in human inflammatory diseases.
Part of the book: Cells of the Immune System
Neuroprotective Properties of Cannabinoids in Cellular and Animal Models: Hypotheses and Facts
Progressive neuronal loss is a typical characteristic of neurodegenerative diseases. In Parkinson’s disease, the loss of dopaminergic neurons in the basal ganglia results in impaired mobility and flawed muscle control. The loss of cholinergic neurons largely in the basal forebrain contributes to memory and attention deficits and the overall cognitive impairment in Alzheimer’s disease. This being said, neuroprotective drugs should be expected to preserve and/or restore the functions affected by neuronal loss, and substantially prevent cell death. The endocannabinoid system, comprising lipid mediators able to bind to and activate cannabinoid receptors, has emerged as a therapeutic target of potential interest in a variety of central nervous system diseases. Palmitoylethanolamide (PEA) is one of the most important endocannabinoids, which has a key role in modulating oxidative stress and inflammatory response with neuroprotective potential in neurological disorders. Neurodegenerative diseases undergo varied, progressive stages. The current therapeutical approaches are beginning to fall short when it comes to meet the expected results, urging to either develop or identify or develop new effective treatments. This chapter discusses the neuroprotective potential of new drugs, aiming to shed some light on their proposed mechanism of action and their effect in cellular and animal models of neurodegeneration.
Part of the book: Neuroprotection
In Vivo Studies of Protein Misfolding and Neurodegeneration Induced by Metabolic Syndrome Relative to Chronic Cerebral Hypoperfusion: A Critical Review
Metabolic syndrome (MetS) leads to microvascular dysfunction and chronic cerebral hypoperfusion (CCH) in an insidious way. Clinical evidence and several rodent models have contributed to determining the neurodegenerative effect of a sustained decrease in cerebral blood flow (CBF). Protein misfolding and aggregation derived from CCH might account for the establishment of vascular cognitive impairment and dementia (VCID) and Alzheimer’s disease (AD). However, the complex and multifactorial etiology of cerebrovascular disease demands the combination of experimental models in scientific research. In this sense, the present work aims at summarizing the differential available rodent paradigms for studying the establishment of cognitive decline resulting from protein misfolding induced by MetS in association with CCH. Revising experimental findings in the field will help further basic research on the pathophysiology of cerebrovascular disease and the future testing of protein-remodeling factors as neuroprotective agents for the prevention of cognitive impairment.
Part of the book: Neuroprotection
Neuroactive Steroids in Hypoxic–Ischemic Brain Injury: Overview and Future Directions
Hypoxic–ischemic brain injury is a number one cause of long-term neurologic disability and death worldwide. This public health burden is mainly characterized by a decrease in oxygen concentration and blood flow to the tissues, which lead to an inefficient supply of nutrients to the brain. This condition induces cell death by energy depletion and increases free radical generation and inflammation. Hypoxic–ischemic brain injury may occur in ischemic-stroke and over perinatal asphyxia, being both leading causes of morbidity in adults and children, respectively. Currently, there are no effective pharmaceutical strategies to prevent the triggering of secondary injury cascades, including oxidative stress and metabolic dysfunction. Neuroactive steroids like selective estrogen receptor modulators, SERMs, and selective tissue estrogenic activity regulators, STEARs, exert several neuroprotective effects. These encompass mitochondrial survival, a decrease in reactive oxygen species, and maintenance of cell viability, among others. In this context, these neurosteroids constitute promising molecules, which could modify brain response to injury. Here we show an updated overview of the underlying mechanisms of hypoxic–ischemic brain injury. We also highlight the neuroprotective effects of neurosteroids and their future directions.
Part of the book: Neuroprotection