PAD2 dysregulation and aberrant protein citrullination feature prominently in reactive astrogliosis and myelin protein aggregation in sporadic ALS.

Alteration in protein citrullination (PC), a common posttranslational modification (PTM), contributes to pathogenesis in various inflammatory disorders. We previously reported that PC and protein arginine deiminase 2 (PAD2), the predominant enzyme isoform that catalyzes this PTM in the central nervous system (CNS), are altered in mouse models of amyotrophic lateral sclerosis (ALS). We now demonstrate that PAD2 expression and PC are altered in human postmortem ALS spinal cord and motor cortex compared to controls, increasing in astrocytes while trending lower in neurons. Furthermore, PC is enriched in protein aggregates that contain the myelin proteins PLP and MBP in ALS. These results confirm our findings in ALS mouse models and suggest that altered PAD2 and PC contribute to neurodegeneration in ALS.

Protein citrullination marks myelin protein aggregation and disease progression in mouse ALS models.

Increased protein citrullination (PC) and dysregulated protein arginine deiminase (PAD) activity have been observed in several neurodegenerative diseases. PC is a posttranslational modification catalyzed by the PADs. PC converts peptidyl-arginine to peptidyl-citrulline, thereby reducing the positive charges and altering structure and function of proteins. Of the five PADs, PAD2 is the dominant isoform in the central nervous system (CNS). Abnormal PC and PAD dysregulation are associated with numerous pathological conditions, including inflammatory diseases and neurodegeneration. Animal model studies have shown therapeutic efficacy from inhibition of PADs, thus suggesting a role of PC in pathogenesis. To determine whether PC contribute to amyotrophic lateral sclerosis (ALS), a deadly neurodegenerative disease characterized by loss of motor neurons, paralysis, and eventual death, we investigated alterations of PC and PAD2 in two different transgenic mouse models of ALS expressing human mutant SOD1G93A and PFN1C71G, respectively. PC and PAD2 expression are altered dynamically in the spinal cord during disease progression in both models. PC and PAD2 increase progressively in astrocytes with the development of reactive astrogliosis, while decreasing in neurons. Importantly, in the spinal cord white matter, PC accumulates in protein aggregates that contain the myelin proteins PLP and MBP. PC also accumulates progressively in insoluble protein fractions during disease progression. Finally, increased PC and PAD2 expression spatially correlate with areas of the CNS with the most severe motor neuron degeneration. These results suggest that altered PC is an integral part of the neurodegenerative process and potential biomarkers for disease progression in ALS. Moreover, increased PC may contribute to disease-associated processes such as myelin protein aggregation, myelin degeneration, and astrogliosis.

Inflammatory Response and Secondary White Matter Damage to the Corpus Callosum after Focal Striatal Stroke in Rats.

Stroke is one of the leading causes of death and long-term disabilities worldwide, resulting in a debilitating condition occasioned by disturbances in the cerebral vasculature. Primary damage due to metabolic collapse is a quick outcome following stroke, but a multitude of secondary events, including excitotoxicity, inflammatory response, and oxidative stress cause further cell death and functional impairment. In the present work, we investigated whether a primary ischemic damage into the dorsal striatum may cause secondary damage in the circumjacent corpus callosum (CC). Animals were injected with endothelin-1 and perfused at 3, 7, 14, and 30 post-lesion days (PLD). Sections were stained with Cresyl violet for basic histopathology and immunolabeled by antibodies against astrocytes (anti-GFAP), macrophages/microglia (anti-IBA1/anti MHC-II), oligodendrocytes (anti-TAU) and myelin (anti-MBP), and Anti-Nogo. There were conspicuous microgliosis and astrocytosis in the CC, followed by later oligodendrocyte death and myelin impairment. Our results suggest that secondary white matter damage in the CC follows a primary focal striatal ischemia in adult rats.

White Matter Microstructure Underlies the Effects of Sleep Quality and Life Stress on Depression Symptomatology in Older Adults.

Sleep complaints are the most prevalent syndromes in older adults, particularly in women. Moreover, they are frequently accompanied with a high level of depression and stress. Although several diffusion tensor imaging (DTI) studies reported associations between sleep quality and brain white matter (WM) microstructure, it is still unclear whether gender impacts the effect of sleep quality on structural alterations, and whether these alterations mediate the effects of sleep quality on emotional regulation. We included 389 older participants (176 females, age = 65.5 ± 5.5 years) from the 1000BRAINS project. Neuropsychological examinations covered the assessments of sleep quality, depressive symptomatology, current stress level, visual working memory, and selective attention ability. Based on the DTI dataset, the diffusion parameter maps, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD), were calculated and normalized to a population-specific FA template. According to the global Pittsburgh Sleep Quality Index (PSQI), 119 poor sleepers (PSQI: 10∼17) and 120 good sleepers (PSQI: 3∼6) were identified. We conducted a two by two (good sleepers/poor sleepers) × (males/females) analysis of variance by using tract-based spatial statistics (TBSS) and JHU-ICBM WM atlas-based comparisons. Moreover, we performed a voxel-wise correlation analysis of brain WM microstructure with the neuropsychological tests. Finally, we applied a mediation analysis to explore if the brain WM microstructure mediates the relationship between sleep quality and emotional regulation. No significant differences in brain WM microstructure were detected on the main effect of sleep quality. However, the MD, AD, and RD of pontine crossing tract and bilateral inferior cerebellar peduncle were significant lower in the males than females. Voxel-wise correlation analysis revealed that FA and RD values in the corpus callosum were positively related with depressive symptomatology and negatively related with current stress levels. Additionally, we found a significantly positive association between higher FA values in visual-related WM tracts and better outcomes in a visual pattern recognition test. Furthermore, a mediation analysis suggested that diffusion metrics within the corpus callosum partially mediated the associations between poor sleep quality/high stress and depressive symptomatology.

Detecting structural and inflammatory response after in vivo stretch injury in the rat median nerve via second harmonic generation.

BACKGROUND: Second Harmonic Generation (SHG) microscopy is a promising method for visualizing the collagenous structure of peripheral nerves. Assessing collagen continuity and damage after a stretch injury provides inferential insight into the level of axonal damage present. NEW METHODS: This study utilizes SHG microscopy after a calibrated in vivo stretch injury of rat median nerves to evaluate collagen continuity at several time points throughout the recovery process. Endoneurial collagen was qualitatively assessed in nerves that were subjected to low strain (LS) and high strain (HS) injuries using SHG microscopy, conventional histology, and immunohistochemistry. RESULTS: Following an in vivo stretch injury, both LS and HS damaged nerves exhibit signs of structural collagen damage in comparison with sham control nerves (SC). Furthermore, LS nerves exhibit signs of full regeneration while HS nerves exhibited signs of only partial regeneration with lasting damage and intra-neural scar formation. COMPARISON WITH EXISTING METHODS: SHG observations of structural changes and inflammatory response due to stretch injury were validated upon comparison with conventional histological methods CONCLUSIONS: We propose that SHG microscopy can be utilized to visualize significant structural artifacts in sectioned median nerves following in vivo stretch injury. Based on the findings in this study, we believe that the in vivo application of SHG microscopy should be further investigated as a means for real-time, intra-operative, quantitative assessment of nerve damage.

Degenerative axonopathy associated with copper deficiency in pigs / Axonopatia degenerativa associada com deficiência de cobre em suínos

The epidemiological, clinic and morphological (pathological and ultrastructural) aspects of four outbreaks of copper deficiency affecting 21- to 90-day-old pigs in the Northeast region of Brazil are reported. Clinical signs began with paraparesis and ataxia and progressed to flaccid or spastic paralysis of the pelvic and thoracic limbs, followed by sternal and/or lateral recumbence. In addition, some animals showed dog-sitting position and intention tremors. The clinical manifestation period was 5-20 days. Significant gross lesions were not observed; however, microscopically, symmetrical degeneration of the white matter with ballooned myelin sheaths containing occasional macrophages was observed, mainly in the spinal cord. Two pigs presented with necrosis ad loss of Purkinje cells and ectopic Purkinje cells in the granular layer and cerebellar white matter. A ultrastructural analysis showed different degrees of damage of myelinated axons in the spinal segments, including an absence of the axoplasm structures with only axonal residues remaining. The myelin sheaths were degenerated and often collapsed into the space previously occupied by the axon. These results suggest that myelin degeneration is secondary to the axonal lesion. Finally, the concentration of copper in the liver was determined using atomic absorption spectrophotometry and was found to be low (ranging from 2.2 to 10.8 ppm). In conclusion, in the Brazilian semiarid region, Cu deficiency occurs in 21 to 90-day-old pigs that ingested different types of waste in their food.(AU)

São relatados os achados epidemiológicos, clínicos e morfológicos (patológicos e ultraestruturais) de quatro surtos de deficiência de cobre em suínos afetados entre 21 e 90 dias de idade na região Nordeste do Brasil. Os sinais clínicos iniciaram com paraparesia e ataxia, que progrediu a paralisia flácida ou espástica dos membros pélvicos e torácicos, seguido de decúbito esternal e/ou lateral. Além disso, alguns animais apresentaram posição de cão sentado e tremores de intenção. O período de manifestação clínica variou de 5-20 dias. Não foram observadas lesões macroscópicas significativas; no entanto, microscopicamente, foi observada degeneração simétrica da substância branca com fragmentação das bainhas de mielina, contendo ocasionais macrófagos, principalmente na medula espinal. Dois suínos apresentaram necrose e perda de células de Purkinje e células de Purkinje ectópicos na camada granular da substância branca cerebelar. A análise ultraestrutural mostrou diferentes graus de lesões em axônios mielinizados em segmentos da medula espinhal, incluindo o desaparecimento de estruturas do axoplasma, restando apenas restos axonais. A bainha de mielina encontrava-se degenerada e muitas vezes, colapsada dentro do espaço previamente ocupado pelo axônio. Esses resultados sugerem que a degeneração da mielina é secundária à lesão axonal. Finalmente, a concentração do cobre no fígado foi determinada usando espectrometria de absorção atômica e revelou baixos valores (variando de 2,2-10,8ppm). Conclui-se que na região semiárida do Brasil ocorre deficiência de cobre em suínos de 21 a 90 dias de idade alimentados com diferentes tipos de resíduos.(AU)

Histopathological and ultra-structural characterization of local neuromuscular damage induced by repeated phosphatidylcholine/deoxycholate injection.

Phosphatidylcholine/deoxycholate (PC/DC) combination is frequently used for injection lipolysis in body contouring and size reduction of subcutaneous lipomas. Nonetheless, studies that assess possible injurious effects of PC/DC combination on tissues at injection sites are inadequate. The current work attempts to evaluate the effects of repeated PC/DC injection on skeletal muscles and neural tissues at the injection site. For this purpose, female Wistar rats were randomly assigned into 2 groups, 10 rats each, and injected percutaneously via either normal saline (control group) or PC/DC (treated group) in the groin area for 4 consecutive days. Biopsies were harvested on the 4(th) day for histopathological studies. The results of the present work demonstrated that repeated injection of PC/DC caused neural damage and intense inflammation at the injection site leading to skeletal muscle degeneration, necrosis and fibrosis. Electron microscopic examination of the neural tissues in the injected area showed intra-neural fibroblasts, deposition of intra-neural collagen fibers and marked myelin degeneration. In addition, PC/DC injection caused thickening of intra-neural blood vessel walls and evident endo-neural mast cells. The current data highlight the attendant risk of neuromuscular injury associated with repeated PC/DC injection during the treatment of undesirable fat deposits and lipomas.

Thymic stromal lymphopoietin is expressed in the intact central nervous system and upregulated in the myelin-degenerative central nervous system.

Thymic stromal lymphopoietin (TSLP) is an epithelial cytokine expressed at barrier surfaces of the skin, gut, nose, lung, and the maternal/fetal interphase. At these sites, it is important for the generation and maintenance of non-inflammatory, tissue-resident dendritic cell responses. We show here that TSLP is also expressed in the central nervous system (CNS) where it is produced by choroid plexus epithelial cells and astrocytes in the spinal cord. Under conditions of low-grade myelin degeneration, the numbers of TSLP-expressing astrocytes increase, and microglia express transcripts for the functional TSLP receptor dimer indicating that these cells are targets for TSLP in the myelin-degenerative CNS.

Morphological Analysis of the Effect of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin on the Peripheral Nervous System of Mouse / 대한해부학회지

Toxicity of TCDD on the peripheral nerve has not yet been clear even though there are many reports about its toxicity on various organs of human and other animals. This study was designed to clarify the effect of TCDD on the peripheral nerve by the morphometric and electron microscopic analysis. Fourty mg/kg of TCDD was injected to 4 week-old C57BL/6J mice intraperitoneally. At the 1st, 4th and 16th weeks after TCDD injection, the 4th lumbar segments of the spinal cord, the same level of spinal ganglia, and the sciatic nerves were taken. They were used for the light and electron microscopic examination and morphometric analysis. The nerve cell bodies of the anterior horn and the spinal ganglia did not show the difference between the TCDD-treated and control groups. Neuronal population of the ganglia of the TCDD-treated group did not differ from that of the control group. Unusually thickened myelin was frequently observed in the TCDD-treated groups, while axonal degeneration was not found in the sciatic nerves of both groups. The cross sectional area of myelin sheaths in the TCDD-treated group of all age was larger than that of the control group. Under the trasmission electron microscope, the myelin of the TCDD-treated group showed that it lost the regular compact arrangement and its lamellar was disrupted. In conclusion, we suggest that TCDD slows down the nerve conduction velocity via the disruption of the myelin structure of the peripheral nerve.

Feature or clinic, pathology and electrophysiology with chronic alcoholic polyneuropathy / 临床神经病学杂志

patients with chronic alcoholic polyneuropathy (CAPN ) were described. They were all male with age rainging from 33 to 70 years (mean age 53. 7). The cardinal symptoms are. pain and numbness in the extremities, stocking and glove decreased of pain and temperature sense in the legs and arms, the loss of vibration sense and muscule atrophy. The motion nerve conducting velocity (MCV) and sensory nerve conduction velocity (SCV) all are slowed in varying degrees. Superficial peroneal nerve biopsy identified myelin degeneration of myelinated nerve fibers, axonal degeneration or disappearance, degeneration of Schwann cell and also involved perineurium. The change was due to avitaminosis for long-term drinking.