Microglia In The Regenerating And Degenerating Central Nervous System

The study of microglial cells has recently gained importance for those researching degeneration and regeneration. Microglia in the regenerating and degenerating CNS supports the assertion that understanding microglial biology could perhaps be pivotal for unraveling the pathogenetic mechanisms that underlie Alzheimer's disease, In addition, microglia are also critical for understanding the sequelae of traumatic brain and spinal cord injury, and for the important post-traumatic repair processes. This book gives an up to date account of the role of microglia in degeneration and regeneration of the nervous system and reviews their cell function and physiology.

Microglial cells play a vital role in the innate immune response occurring in the Central Nervous System (CNS). Under physiologic conditions, microglia dynamically patrol the brain parenchyma and participate in the remodeling of active neuronal circuits. Accordingly, microglia can boost synaptic plasticity by removing apoptotic cells and by phagocytizing axon terminals and dendritic spines that form inappropriate neural connections. Upon brain and spinal cord injury or infection, microglia act as the first line of immune defense by promoting the clearance of damaged cells or infectious agents and by releasing neurotrophins and/ or proneurogenic factors that support neuronal survival and regeneration. Recently, two main pathways were suggested for microglia activation upon stimuli. Classical activation is induced by Toll-like receptor agonists and Th1 cytokines and polarizes cells to an M1 state, mainly leading to the release of TNF-alpha, IL-6 and nitric oxide and to grave neural damage. Alternative activation is mediated by Th2 cytokines and polarizes cells to an M2a state inducing the release of antiinflammatory factors. These findings have further fueled the discussion on whether microglia has a detrimental or beneficial action (M1 or M2-associated phenotypes, respectively) in the diseased or injured CNS and, more importantly, on whether we can shift the balance to a positive outcome. Although microglia and macrophages share several common features, upon M1 and M2 polarizing conditions, they are believed to develop distinct phenotypic and functional properties which translate into different patterns of activity. Moreover, microglia/macrophages seem to have developed a tightly organized system of maintenance of CNS homeostasis, since cells found in different structures have different morphology and specific function (e.g. meningeal macrophages, perivascular macrophages, choroid plexus macrophages). Nevertheless, though substantial work has been devoted to microglia function, consensus around their exact origin, their role during development, as well as the exact nature of their interaction with other cells of the CNS has not been met. This issue discusses how microglial cells sustain neuronal activity and plasticity in the healthy CNS as well as the cellular and molecular mechanisms developed by microglia in response to injury and disease. Understanding the mechanisms involved in microglia actions will enforce the development of new strategies to promote an efficient CNS repair by committing microglia towards neuronal survival and regeneration.

Degeneration and Regeneration in the Nervous System brings together an international team of contributors to produce a series of critical reviews appraising key papers in the field. The pace of research on brain and spinal cord injury quickened considerably in the last ten years and there is much that is new and important that is covered in this book. However, there is still a long way to go before our knowledge will explain fully why the central nervous system has such a limited capacity for regeneration, and before experimental solutions can be applied to the patient. With emphasis on actual and therapeutic importance of the work reviewed, Degeneration and Regeneration in the Nervous System is a useful overview for graduate students, their teachers and researchers working in this field.

These past few years have witnessed a revolution in our understanding of microglia, especially since their roles in the healthy central nervous system (CNS) have started to unravel. These cells were shown to actively maintain health, in concert with neurons and other types of CNS cells, providing further insight into their involvement with diseases. Edited by two pioneers in the field, Marie-Ève Tremblay and Amanda Sierra, Microglia in health and disease aims to share with the broader scientific community some of the recent discoveries in microglia research, from a broad perspective, with a collection of 19 chapters from 52 specialists working in 11 countries across 5 continents. To set microglia on the stage, the book begins by explaining briefly who they are, what they do in the healthy and diseased CNS, and how they can be studied. The first section describes in more details their physiological roles in the maturation, function, and plasticity of the CNS, across development, adolescence, adulthood, neuropathic pain, addiction, and aging. The second section focuses on their implication in pathological conditions impairing the quality of life: neurodevelopmental and neuropsychiatric disorders, AIDS, and multiple sclerosis; and in leading causes of death: ischemia and stroke, neurodegenerative diseases, as well as trauma and injury.

Microglia are essential for the development and function of the adult brain. Their ontogeny, together with the absence of turnover from the periphery and the singular environment of the central nervous system (CNS), make microglia a unique cell population compared to other tissue-macrophages. The unique properties and functions of microglial cells, such as their role in synaptic pruning or the exceptional capacity to scan the brain parenchyma and rapidly react to its perturbations, have emerged in recent years. In the coming years, understanding how microglia acquire and maintain their unique profiles in order to fulfil distinct tasks in the healthy CNS and how these are altered in disease, will be essential to develop strategies to diagnose or treat CNS disorders with an immunological component. This Research Topic covers several aspects of microglial biology, ranging from their origin and the functional role of microglia during development and lifespan, their molecular properties compared with other brain and peripheral immune cells to microglial phenotypes and functional states in neurodegenerative diseases and brain tumours. In conclusion, the present Research Topic provides a comprehensive overview of our current understanding of several cellular and molecular mechanisms that make microglia a unique immune cell population within the healthy CNS as well as under inflammatory, neurodegenerative and tumorigenic processes.

This book is a reprint of an English translation of Cajal's original work, with abundant notes and commentaries by the editor. This text describes Cajal's fundamental contributions to neuroscience, which continue to be important today. It accurately details Cajal's ideas and data, and providesreaders with the opportunity to learn what Cajal thought about his research career and the significance of his observations. Excerpts from Tello's memorial lectures also provide a contemporary view of Cajal's work.

Despite enormous advances made in the development of external effector prosthetics over the last quarter century, significant questions remain, especially those concerning signal degradation that occurs with chronically implanted neuroelectrodes. Offering contributions from pioneering researchers in neuroprosthetics and tissue repair, Indwelling Neural Implants: Strategies for Contending with the In Vivo Environment examines many of these challenges, paying particular attention to how the healing of tissues surrounding an implant can impact the intended use of a device. The contributions are divided into four sections · Part one examines wound healing from the initial insertion trauma through the inflammatory and repair process, explaining how the action of healing varies throughout different areas of the body. · Part two considers various performance issues specific to particular implant components, including those that arise from the chemical, mechanical, thermal, and electrical impact on surrounding tissues. It discusses challenges that result from chronic tissue stimulation and heat effects that occur with on-chip and telemetric processing. · Part three presents both in vitro and in vivo approaches to assessing wound healing response to materials. It includes the contribution of the developer of a chronic hollow fiber membrane implant who explains how an in vivo model is used to assess molecular transport in brain tissue surrounding the implant. · The final section evaluates molecular and materials strategies for intervening in CNS wound repair and enhancing the electrical communication between the electrode surface and the surrounding tissue. It also presents novel approaches to nerve regeneration and repair. This seminal work provides researchers with an up-to-date account of the progress in the field that they can build upon to bring us closer to realizing the full value of neural implants in combating otherwise intractable human health problems.

These volumes teach readers to think beyond apoptosis and describes all of the known processes that cells can undergo which result in cell death This two-volume source on how cells dies is the first, comprehensive collection to cover all of the known processes that cells undergo when they die. It is also the only one of its kind to compare these processes. It seeks to enlighten those in the field about these many processes and to stimulate their thinking at looking at these pathways when their research system does not show signs of activation of the classic apoptotic pathway. In addition, it links activities like the molecular biology of one process (eg. Necrosis) to another process (eg. apoptosis) and contrasts those that are close to each. Volume 1 of Apoptosis and Beyond: The Many Ways Cells Die begins with a general view of the cytoplasmic and nuclear features of apoptosis. It then goes on to offer chapters on targeting the cell death mechanism; microbial programmed cell death; autophagy; cell injury, adaptation, and necrosis; necroptosis; ferroptosis; anoikis; pyronecrosis; and more. Volume 2 covers such subjects as phenoptosis; pyroptosis; hematopoiesis and eryptosis; cyclophilin d-dependent necrosis; and the role of phospholipase in cell death. Covers all known processes that dying cells undergo Provides extensive coverage of a topic not fully covered before Offers chapters written by top researchers in the field Provides activities that link and contrast processes to each other Apoptosis and Beyond: The Many Ways Cells Die will appeal to students and researchers/clinicians in cell biology, molecular biology, oncology, and tumor biology.