Brain and Nerve最新文献

Anti-aminoacyl tRNA synthetase (ARS) antibodies are the most frequent in idiopathic inflammatory myopathy, notably associated with anti-synthetase syndrome (ASyS), which is characterized by six clinical features: arthritis, myositis, interstitial lung disease (ILD), fever, Raynaud's phenomenon, and mechanical hands. Although patients with ASyS often respond well to initial glucocorticoid (GC) therapy, they tend to have a chronic, recurrent disease course. In anti-ARS-positive patients, the treatment goal involves suppressing disease recurrence and progression while achieving a minimal GC dose. In this regard, the administration and continuation of immunosuppressants, such as calcineurin inhibitors, have been suggested. B-cell depletion therapies are expected to be valuable in patients with refractory ASyS. Moreover, additional antifibrotic agents may be beneficial for patients with progressive fibrosing ILD.

Neuropathological findings rarely lead to a definitive diagnosis of autoimmune and inflammatory peripheral nerve diseases, and indications for invasive nerve biopsy with subsequent disability should be carefully determined. In addition to disease-specific pathological findings, identifying findings that facilitate differential diagnosis in clinical practice is necessary. This article reviews the neuropathological findings that are valuable in the differential diagnosis of autoimmune and inflammatory peripheral nerve diseases.

Guillain-Barré syndrome (GBS), an acute immune-mediated neuropathy, occurs following immunological stimulation, such as infection, with complement-mediated neuropathy implicated in the pathophysiology of this condition. Glycolipid antibodies produced by molecular mimicry are detected in approximately 60% of cases. Recent studies have suggested the role of cell-mediated immunity in the pathogenesis of GBS. Intravenous immunoglobulin and plasma exchange are established immunotherapies. In this article, based on the latest knowledge, we describe the pathophysiology, diagnosis, treatment, prognosis, and prognostic prediction of GBS. Furthermore, we discuss some GBS guidelines published by the European Academy of Neurology/Peripheral Nerve Society.

Measurement of autoantibodies is essential for the management of several peripheral nerve and muscle diseases. The clinical significance of autoantibody testing differs for each antibody. In addition, clinicians must understand several issues including the accuracy of the test, isotype and subclass distribution, and its relationship to disease activity. Moreover, many autoantibody tests are not covered by health insurance. With limited medical resources, clinicians are required to be up-to-date with the latest information to utilize test results in daily practice without misunderstanding.

Diabetes stands as the predominant cause of peripheral neuropathy, and diabetic neuropathy (DN) is an early-onset and most frequent complication of diabetes. Distal symmetric polyneuropathy is the major form of DN; however, various patterns of nerve injury can manifest. Growing evidence suggests that hyperglycemia-related metabolic disorders in neurons, Schwann cells, and vascular endothelial cells play a major role in the development and progression of DN; however, its pathogenesis and development of disease-modifying therapies warrant further investigation. Herein, recent studies regarding the possible pathogenic factors of DN (polyol and other collateral glycolysis pathways, glycation, oxidative stress, Rho/Rho kinase signaling pathways, etc.) and therapeutic strategies targeting these factors are introduced.

Reportedly, patients with muscle-specific kinase (MuSK) antibody-positive myasthenia gravis (MG) account for approximately 3.0% of all patients with MG in Japan. Compared with patients who have acetylcholine receptor antibody-positive MG, those with MuSK antibody-positive MG show young-onset disease with female predominance, a low rate of ocular involvement (5.9%), and greater severity of dysphagia. The aforementioned types of MG are indistinguishable based on clinical symptoms and electrophysiological tests, and measurement of MuSK antibodies is essential for diagnosis. Thymectomy and complement inhibitors are not indicated for treatment, and acetylcholinesterase inhibitors, steroids, immunosuppressants, plasma exchange, intravenous immunoglobulin therapy, and neonatal Fc receptor inhibitors are used.

Sjögren's syndrome is often accompanied by various neurological complications, among which peripheral neuropathy is the most common. A variety of clinical phenotypes of peripheral neuropathy, including axonal polyneuropathy and sensory ataxic neuropathy are reported in the literature. We present an overview of the pathophysiology and differential diagnosis of each phenotype. Immunotherapy using corticosteroids and high-dose intravenous immunoglobulin therapy tends to elicit varied therapeutic responses depending on the peripheral neuropathy phenotype. We also discuss myositis, a possible complication of Sjögren's syndrome.

Dementia is characterized by acquired cognitive dysfunction caused by various neurological disorders. Many neurological conditions can cause dementia, including neurodegenerative diseases, vascular disorders, infections, inflammation, demyelination, intoxication, metabolic disorders, tumors, and head trauma. Despite recent developments in biomarkers and imaging techniques, neuropathological examination is necessary for the final diagnosis. Moreover, approximately 11% of the patients with dementia have dual or triple pathological conditions. The coexistence of neurological diseases makes it difficult for neurologists to diagnose patients accurately. Degenerative diseases are characterized by neuronal loss with gliosis in distinct parts of the brain, the presence of neuronal or glial inclusions, and abnormal protein accumulation. Senile plaques and neurofibrillary tangles are neuropathological hallmarks of Alzheimer's disease. These findings are characterized by the presence of amyloid β protein (Aβ) and phosphorylated tau protein, respectively. Although vascular dementia is common, it may be difficult to identify the relationship between vascular lesions and cognitive impairment. The incidence of sporadic Aβ-type cerebral amyloid angiopathy (CAA) tends to increase with age and causes dementia due to vascular dysfunction and leukoencephalopathy. Furthermore, patients with CAA can develop inflammation. Clinical neurologists should possess a neuropathological perspective for the appropriate diagnosis and management of patients with dementia.

A definite diagnosis of neurodegenerative diseases is required for neuropathological examination during an autopsy. Each neurodegenerative disease has specific vulnerable regions and affected systems (system degeneration), and is typified by an accumulation of abnormal protein with the formation of characteristic morphological aggregates in the nerve and glial cells, called proteinopathy. The most common neurodegenerative diseases are tauopathy, such as progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and Pick's disease (PiD); α-synucleinopathy, including multiple system atrophy (MSA); and TAR DNA-binding protein of 43 kDa (TDP-43) proteinopathy, including amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). PSP and CBD show characteristic tau-positive astrocytic inclusions known as tufted astrocytes and astrocytic plaques, respectively. PiD shows tau-positive neuronal inclusions termed Pick bodies. MSA is characterized by α-synuclein-positive oligodendroglial inclusions, called glial cytoplasmic inclusions. ALS- and FTLD-TDP show TDP-43-positive neuronal inclusions, such as skein-like and round inclusions. Huntington's disease shows polyglutamine-positive neuronal inclusions, and Creutzfeldt-Jakob disease shows diffuse deposition of granular prions in the neuropil. The atypical proteins in these diseases have abnormal conformational properties. A comprehensive comparison of the clinical findings and neuropathological observations, including neuroanatomy and images acquired during life, is important to improve the sensitivity of clinical diagnosis.

Amyloid fibril formation is a general property of proteins and peptides. It is a physicochemical phenomenon similar to crystallization, in which amyloid precursor proteins exceeding solubility precipitate through the breakdown of supersaturation. Using the ultrasonication-forced amyloid fibril inducer HANABI, we have discovered that serum albumin acts as an inhibitor in dialysis-related amyloidosis. Exploring the factors that induce or inhibit amyloid fibril formation using HANABI can lead to the development of early diagnosis and prevention methods for amyloidosis.