Free Neuropathology https://www.uni-muenster.de/Ejournals/index.php/fnp <p><em>Free Neuropathology</em> is a non-commercial journal that is run by Neuropathologists and other Neuroscientists and publishes papers on Human and Experimental Neuropathology. It is free for authors, free for readers, free from publishers, free from excessive formalities, and it encourages exchange of free opinions.</p> <p><em>Free Neuropathology</em> is not just another open-access online journal. It is a new type of journal edited and published by scientists working in the field. We do not have any financial interests, and we strongly feel that the huge amount of money currently spent for increasing the profit of publishers should be better invested into science. We believe that the usual activities of publishers such as copyediting, layout, hosting of articles, maintenance of the website and promotion could and should be overtaken by scientists in order to restitute scientific freedom. There is no article processing fee and no paywall -- the journal is free for everyone ("Diamond Open Access"). We try to reduce technicalities to a minimum. This grassroots development is managed by enthusiastic neuroscientists and it may be the future of publishing.</p> en-US Free Neuropathology 2699-4445 <p>Papers are published open access under the Creative Commons BY 4.0 license.&nbsp;This license lets others distribute, remix, adapt, and build upon your work, even commercially, as long as they credit you for the original creation. Data included in the article are made available under the CC0 1.0 Public Domain Dedication waiver, unless otherwise stated, meaning that all copyrights are waived.</p> Neuromuscular disease: 2021 update https://www.uni-muenster.de/Ejournals/index.php/fnp/article/view/3236 <p>This review highlights ten important advances in the neuromuscular disease field that were first reported in 2020. The overarching topics include (i) advances in understanding of fundamental neuromuscular biology; (ii) new / emerging diseases; (iii) advances in understanding of disease etiology and pathogenesis; (iv) diagnostic advances; and (v) therapeutic advances. Within this broad framework, the individual disease entities that are discussed in more detail include neuromuscular complications of COVID-19, supervillin-deficient myopathy, 19p13.3-linked distal myopathy, vasculitic neuropathy due to eosinophilic granulomatosis with polyangiitis, spinal muscular atrophy, idiopathic inflammatory myopathies, and transthyretin neuropathy/myopathy. In addition, the review highlights several other advances (such as the revised view of the myofibrillar architecture, new insights into molecular and cellular mechanisms of muscle regeneration, and development of new electron microscopy tools) that will likely have a significant impact on the overall neuromuscular disease field going forward.</p> Marta Margeta ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-02-23 2021-02-23 2 3 3 10.17879/freeneuropathology-2021-3236 Neuropathology of COVID-19 (neuro-COVID): clinicopathological update https://www.uni-muenster.de/Ejournals/index.php/fnp/article/view/2993 <p>Coronavirus disease 2019 (COVID-19) is emerging as the greatest public health crisis in the early 21<sup>st</sup> century. Its causative agent, Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), is an enveloped single-stranded positive-sense ribonucleic acid virus that enters cells via the angiotensin converting enzyme 2 receptor or several other receptors. While COVID-19 primarily affects the respiratory system, other organs including the brain can be involved. In Western clinical studies, relatively mild neurological dysfunction such as anosmia and dysgeusia is frequent (~70-84%) while severe neurologic disorders such as stroke (~1-6%) and meningoencephalitis are less common. It is unclear how much SARS-CoV-2 infection contributes to the incidence of stroke given co-morbidities in the affected patient population. Rarely, clinically-defined cases of acute disseminated encephalomyelitis, Guillain-Barré syndrome and acute necrotizing encephalopathy have been reported in COVID-19 patients. Common neuropathological findings in the 184 patients reviewed include microglial activation (42.9%) with microglial nodules in a subset (33.3%), lymphoid inflammation (37.5%), acute hypoxic-ischemic changes (29.9%), astrogliosis (27.7%), acute/subacute brain infarcts (21.2%), spontaneous hemorrhage (15.8%), and microthrombi (15.2%). In our institutional cases, we also note occasional anterior pituitary infarcts. COVID-19 coagulopathy, sepsis, and acute respiratory distress likely contribute to a number of these findings. When present, central nervous system lymphoid inflammation is often minimal to mild, is detected best by immunohistochemistry and, in one study, indistinguishable from control sepsis cases. Some cases evince microglial nodules or neuronophagy, strongly supporting viral meningoencephalitis, with a proclivity for involvement of the medulla oblongata. The virus is detectable by reverse transcriptase polymerase chain reaction, immunohistochemistry, or electron microscopy in human cerebrum, cerebellum, cranial nerves, olfactory bulb, as well as in the olfactory epithelium; neurons and endothelium can also be infected. Review of the extant cases has limitations including selection bias and limited clinical information in some cases. Much remains to be learned about the effects of direct viral infection of brain cells and whether SARS-CoV-2 persists long-term contributing to chronic symptomatology.</p> Jerry J Lou Mehrnaz Movassaghi Dominique Gordy Madeline G Olson Ting Zhang Maya S Khurana Zesheng Chen Mari Perez-Rosendahl Samasuk Thammachantha Elyse J Singer Shino D Magaki Harry V Vinters William H Yong ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-01-18 2021-01-18 2 2 2 10.17879/freeneuropathology-2021-2993 Neuroinflammation: 2021 update https://www.uni-muenster.de/Ejournals/index.php/fnp/article/view/3166 <p>Key requirements for the validity of a neuropathological study are the inclusion of large numbers of biopsy or autopsy cases and proper controls, the rigorous classification of the basic neuropathology and the selection of the most suitable technologies for investigation. Whether the studies are performed with the fanciest, new, and state of the art technology or with rather conventional methodology is of minor importance. Fol-lowing these criteria, a spectrum of neuropathological studies has been published in 2020, which provides new insights on important questions related to neurological disease. They include the pathological substrate of brain disease in COVID-19 infected patients, the nature of the adaptive and innate inflammatory response, or the type and mechanisms of tissue injury and repair in multiple sclerosis, and diagnostically relevant or mechanistic new insights into antibody-mediated diseases of the central nervous system. Other studies de-scribe in detail the dynamic changes of brain inflammation in patients with trisomy 21 as a disease model for Alzheimer’s disease, or the presence and consequences of vascular comorbidities in a chronic inflammatory disease, such as multiple sclerosis. All these contributions have provided important, highly relevant clues for basic and translational neuroscience.</p> Hans Lassmann ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-01-12 2021-01-12 2 1 1 10.17879/freeneuropathology-2021-3166