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Introduction: Chronic muscle pain is common in myotonic dystrophies (DM). Little is known about its pathophysiology. We aimed to investigate the characteristics of the neuropathic pain component contributing contributes to the pathogenesis of chronic pain in DM. Methods: Twenty-one DM1 and 32 DM2 patients completed pain questionnaires (Brief pain inventory--BPI, PAIN-DETECT, pain disability index--PDI) and underwent neurological examination, nerve conduction studies (NCS), quantitative sensory testing (QST, dorsum of the right hand and right thigh) and skin biopsy to determine the intraepidermal nerve fiber density (IENFD, distal and proximal site of lower extremity). NCS and QST results at the thigh were compared to 27 healthy controls and IENFD and QST at the dorsum of the hand to published reference values. Results: The sensory profile of DM2 patients was characterized by a loss in thermal and mechanical detection, while DM1 patients showed reduced mechanical and heat pain thresholds and higher mechanical pain sensitivity. Both DM groups showed pressure hyperalgesia. IENFD was reduced in 63% of DM1 patients and 50% of DM2. The slightly higher pain interference and disability found in DM2 was rather due to age difference than disease. Conclusion: Similar pain mechanisms likely occur in both DM1 and DM2, even though a tendency toward more pain sensitivity was observed in DM1 and more sensory loss in DM2. Both QST and reduced IENFD highlight the presence of peripheral nerve damage in DM. This must be considered for the best pain management strategies. [ABSTRACT FROM AUTHOR]

Aims: Diagnosis of idiopathic inflammatory myopathies (IIM) is based on morphological characteristics and the evaluation of disease‐related proteins. However, although broadly applied, substantial bias is imposed by the respective methods, observers and individual staining approaches. We aimed to quantify the protein levels of major histocompatibility complex (MHC)‐1, (MHC)‐2 and intercellular adhesion molecule (ICAM)‐1 using an automated morphometric method to mitigate bias. Methods: Double immunofluorescence staining was performed on whole muscle sections to study differences in protein expression in myofibre and endomysial vessels. We analysed all IIM subtypes including dermatomyositis (DM), anti‐synthetase syndrome (ASyS), inclusion body myositis (IBM), immune‐mediated‐necrotising myopathy (IMNM), dysferlinopathy (DYSF), SARS‐CoV‐2 infection and vaccination‐associated myopathy. Biopsies with neurogenic atrophy (NA) and normal morphology served as controls. Bulk RNA‐Sequencing (RNA‐Seq) was performed on a subset of samples. Results: Our study highlights the significance of MHC‐1, MHC‐2 and ICAM‐1 in diagnosing IIM subtypes and reveals distinct immunological profiles. RNASeq confirmed the precision of our method and identified specific gene pathways in the disease subtypes. Notably, ASyS, DM and SARS‐CoV‐2‐associated myopathy showed increased ICAM‐1 expression in the endomysial capillaries, indicating ICAM‐1‐associated vascular activation in these conditions. In addition, ICAM‐1 showed high discrimination between different subgroups with high sensitivity and specificity. Conclusions: Automated morphometric analysis provides precise quantitative data on immune‐associated proteins that can be integrated into our pathophysiological understanding of IIM. Further, ICAM‐1 holds diagnostic value for the detection of IIM pathology. [ABSTRACT FROM AUTHOR]

Synaptopodin-2 (SYNPO2) is a protein associated with the Z-disc in striated muscle cells. It interacts with α-actinin and filamin C, playing a role in Z-disc maintenance under stress by chaperone-assisted selective autophagy (CASA). In smooth muscle cells, SYNPO2 is a component of dense bodies. Furthermore, it has been proposed to play a role in tumor cell proliferation and metastasis in many different kinds of cancers. Alternative transcription start sites and alternative splicing predict the expression of six putative SYNPO2 isoforms differing by extended amino- and/or carboxy-termini. Our analyses at mRNA and protein levels revealed differential expression of SYNPO2 isoforms in cardiac, skeletal and smooth muscle cells. We identified synemin, an intermediate filament protein, as a novel binding partner of the PDZ-domain in the amino-terminal extension of the isoforms mainly expressed in cardiac and smooth muscle cells, and demonstrated colocalization of SYNPO2 and synemin in both cell types. A carboxy-terminal extension, mainly expressed in smooth muscle cells, is sufficient for association with dense bodies and interacts with α-actinin. SYNPO2 therefore represents an additional and novel link between intermediate filaments and the Z-discs in cardiomyocytes and dense bodies in smooth muscle cells, respectively. In pathological skeletal muscle samples, we identified SYNPO2 in the central and intermediate zones of target fibers of patients with neurogenic muscular atrophy, and in nemaline bodies. Our findings help to understand distinct functions of individual SYNPO2 isoforms in different muscle tissues, but also in tumor pathology. [ABSTRACT FROM AUTHOR]

This article explores the distribution and composition of the ferritin complex in the adult brain and its connection to neuroferritinopathy (NF), a type of neurodegeneration with brain iron accumulation (NBIA). NF is characterized by symptoms like movement disturbances and tremors. The study identifies a novel variant in the ferritin heavy chain gene (FTH1) that is associated with NF and provides insights into the role of ferritin in both healthy and diseased brains. [Extracted from the article]

G-ratio is crucial for understanding the nervous system's health and function as it measures the relative myelin thickness around an axon. However, manual measurement is biased and variable, emphasizing the need for an automated and standardized technique. Although deep learning holds promise, current implementations lack clinical relevance and generalizability. This study aimed to develop an automated pipeline for selecting nerve fibers and calculating relevant g-ratio using quality parameters in optical microscopy. Histological sections from the sciatic nerves of 16 female mice were prepared and stained with either p-phenylenediamine (PPD) or toluidine blue (TB). A custom UNet model was trained on a mix of both types of staining to segment the sections based on 7,694 manually delineated nerve fibers. Post-processing excluded nonrelevant nerves. Axon diameter, myelin thickness, and g-ratio were computed from the segmentation results and its reliability was assessed using the intraclass correlation coefficient (ICC). Validation was performed on adjacent cuts of the same nerve. Then, morphometrical analyses of both staining techniques were performed. High agreement with the ground truth was shown by the model, with dice scores of 0.86 (axon) and 0.80 (myelin) and pixel-wise accuracy of 0.98 (axon) and 0.94 (myelin). Good inter-device reliability was observed with ICC at 0.87 (g-ratio) and 0.83 (myelin thickness), and an excellent ICC of 0.99 for axon diameter. Although axon diameter significantly differed from the ground truth (p = 0.006), g-ratio (p = 0.098) and myelin thickness (p = 0.877) showed no significant differences. No statistical differences in morphological parameters (g-ratio, myelin thickness, and axon diameter) were found in adjacent cuts of the same nerve (ANOVA p-values: 0.34, 0.34, and 0.39, respectively). Comparing all animals, staining techniques yielded significant differences in mean g-ratio (PPD: 0.48 ± 0.04, TB: 0.50 ± 0.04), myelin thickness (PPD: 0.83 ± 0.28 μm, TB: 0.60 ± 0.20 μm), and axon diameter (PPD: 1.80 ± 0.63 μm, TB: 1.78 ± 0.63 μm). The proposed pipeline automatically selects relevant nerve fibers for g-ratio calculation in optical microscopy. This provides a reliable measurement method and serves as a potential pre-selection approach for large datasets in the context of healthy tissue. It remains to be demonstrated whether this method is applicable to measure g-ratio related with neurological disorders by comparing healthy and pathological tissue. Additionally, our findings emphasize the need for careful interpretation of inter-staining morphological parameters. [ABSTRACT FROM AUTHOR]

Pompe disease is a rare genetic metabolic disorder caused by mutations in acid-alpha glucoside (GAA) leading to pathological lysosomal glycogen accumulation associated with skeletal muscle weakness, respiratory difficulties and cardiomyopathy, dependent from the GAA residual enzyme activity. This study aimed to investigate early proteomic changes in a mouse model of Pompe disease and identify potential therapeutic pathways using proteomic analysis of skeletal muscles from pre-symptomatic Pompe mice. For this purpose, quadriceps samples of Gaa6neo/6neo mutant (Pompe) and wildtype mice, at the age of six weeks, were studied with three biological replicates for each group. The data were validated with skeletal muscle morphology, immunofluorescence studies and western blot analysis. Proteomic profiling identified 538 significantly upregulated and 16 significantly downregulated proteins in quadriceps muscles derived from Pompe animals compared to wildtype mice. The majority of significantly upregulated proteins were involved in metabolism, translation, folding, degrading and vesicular transport, with some having crucial roles in the etiopathology of other neurological or neuromuscular diseases. This study highlights the importance of the early diagnosis and treatment of Pompe disease and suggests potential add-on therapeutic strategies targeting protein dysregulations. [ABSTRACT FROM AUTHOR]

Background: Cardiomyopathies (CMs) are a heterogeneous and severe group of diseases that shows a highly variable cardiac phenotype and an incidence of app. 1/100.000. Genetic screening of family members is not yet performed routinely. Patients and methods: Three families with dilated cardiomyopathy (DCM) and pathogenic variants in the troponin T2, Cardiac Type (TNNT2) gene were included. Pedigrees and clinical data of the patients were collected. The reported variants in the TNNT2 gene showed a high penetrance and a poor outcome, with 8 of 16 patients dying or receiving heart transplantation. The age of onset varied from the neonatal period to the age of 52. Acute heart failure and severe decompensation developed within a short period in some patients. Conclusion: Family screening of patients with DCM improves risk assessment, especially for individuals who are currently asymptomatic. Screening contributes to improved treatment by enabling practitioners to set appropriate control intervals and quickly begin interventional measures, such as heart failure medication or, in selected cases, pulmonary artery banding. [ABSTRACT FROM AUTHOR]

Cats are known to be affected by hippocampal sclerosis, potentially causing antiseizure drug(s) resistance. In order to lay the foundation for a standardized, systematic classification and diagnosis of this pathology in cats, this prospective study aimed at evaluating normal reference values of cellular densities and the cytoarchitecture of the feline hippocampus. Three transverse sections (head, body and tail) of each left hippocampus were obtained from 17 non-epileptic cats of different brachycephalic and mesocephalic breeds and age classes (range: 3–17 years). Histological (hematoxylin and eosin, Nissl) and immunohistochemical (NeuN, GFAP) staining was performed to investigate neuron and astroglial cell populations, as well as the layer thickness of the pyramidal cell layer and granule cell layer. Significant differences in neuronal density (in CA2-CA4 and the granule cell layer) and layer thickness (in CA1-CA3 and the granule cell layer) were evidenced throughout the longitudinal hippocampal axis (p<0.05); on the other hand, the astrocyte density did not differ. Moreover, reference ranges were defined for these parameters in the pyramidal cell layer and in the granule cell layer. The findings did not differ according to breed or age. In veterinary medicine these parameters have not been evaluated in cats so far. As surgical treatment may become a therapeutic option for cats with temporal lobe epilepsy, estimating normal values of the hippocampal cytoarchitecture will help in the standardized histopathological examination of resected hippocampal specimens to reach a diagnosis of hippocampal sclerosis. [ABSTRACT FROM AUTHOR]

The synthesis of cytochrome c oxidase 2 (SCO2) gene encodes for a mitochondrial located metallochaperone essential for the synthesis of the cytochrome c oxidase (COX) subunit 2. Recessive mutations in SCO2 have been reported in several cases with fatal infantile cardioencephalomyopathy with COX deficiency and in only four cases with axonal neuropathy. Here, we identified a homozygous pathogenic variant (c.361G > C; p.[Gly121Arg]) in SCO2 in two brothers with isolated axonal motor neuropathy. To address pathogenicity of the amino acid substitution, biochemical studies were performed and revealed increased level of the mutant SCO2‐protein and dysregulation of COX subunits in leukocytes and moreover unraveled decrease of proteins involved in the manifestation of neuropathies. Hence, our combined data strengthen the concept of SCO2 being causative for a very rare form of axonal neuropathy, expand its molecular genetic spectrum and provide first biochemical insights into the underlying pathophysiology. [ABSTRACT FROM AUTHOR]

Atypical myopathy (AM) is an acute seasonal rhabdomyolysis seen primarily in equids, caused by the ingestion of sycamore maple samaras containing hypoglycin A (HGA) and methylenecyclopropyl-glycine (MCPG). Toxic metabolites inhibit acyl-CoA dehydrogenases and enoyl-CoA hydratases, causing selective hyaline degeneration of type I muscle fibers. Two zoo-kept Bactrian camels (Camelus bactrianus) with a fatal course of AM had sudden onset of muscle pain and weakness, recumbency, and dysphagia, accompanied by increased serum creatine kinase activity and detection in serum of HGA, MCPG, and metabolites. Medical treatment was ineffective. At postmortem examination, sycamore maple tree material was found within the first gastric compartment of the 2-y-old gelding. Although musculature was macroscopically normal, histologically, monophasic hyaline degeneration was marked within type I fibers of intercostal and hypoglossal muscles of the gelding, and in neck, tongue, and masticatory muscles of the cow. The ingestion of sycamore maple material can cause AM in Bactrian camels, and trees of the Sapindaceae family should be avoided in enclosures. [ABSTRACT FROM AUTHOR]

Objective: Precursors of peptide hormones undergo posttranslational modifications within the trans-Golgi network (TGN). Dysfunction of proteins involved at different steps of this process cause several complex syndromes affecting the central nervous system (CNS). We aimed to clarify the genetic cause in a group of patients characterized by hypopituitarism in combination with brain atrophy, thin corpus callosum, severe developmental delay, visual impairment, and epilepsy.Methods: Whole exome sequencing was performed in seven individuals of six unrelated families with these features. Postmortem histopathological and HID1 expression analysis of brain tissue and pituitary gland were conducted in one patient. Functional consequences of the homozygous HID1 variant p.R433W were investigated by Seahorse XF Assay in fibroblasts of two patients.Results: Bi-allelic variants in the gene HID1 domain-containing protein 1 (HID1) were identified in all patients. Postmortem examination confirmed cerebral atrophy with enlarged lateral ventricles. Markedly reduced expression of pituitary hormones was found in pituitary gland tissue. Colocalization of HID1 protein with the TGN was not altered in fibroblasts of patients compared to controls, while the extracellular acidification rate upon stimulation with potassium chloride was significantly reduced in patient fibroblasts compared to controls.Interpretation: Our findings indicate that mutations in HID1 cause an early infantile encephalopathy with hypopituitarism as the leading presentation, and expand the list of syndromic CNS diseases caused by interference of TGN function. ANN NEUROL 2021;90:149-164. [ABSTRACT FROM AUTHOR]

Dermatomyositis (DM) is a systemic idiopathic inflammatory disease affecting skeletal muscle and skin, clinically characterized by symmetrical proximal muscle weakness and typical skin lesions. Recently, myositis‐specific autoantibodies (MSA) became of utmost importance because they strongly correlate with distinct clinical manifestations and prognosis. Antibodies against transcription intermediary factor 1γ (TIF‐1γ) are frequently associated with increased risk of malignancy, a specific cutaneous phenotype and limited response to therapy in adult DM patients. Anti‐Mi‐2 autoantibodies, in contrast, are typically associated with classic DM rashes, prominent skeletal muscle weakness, better therapeutic response and prognosis, and less frequently with cancer. Nevertheless, the sensitivity of autoantibody testing is only moderate, and alternative reliable methods for DM patient stratification and prediction of cancer risk are needed. To further investigate these clinically distinct DM subgroups, we herein analyzed 30 DM patients (n = 15 Mi‐2+ and n = 15 TIF‐1 γ+) and n = 8 non‐disease controls (NDC). We demonstrate that the NanoString technology can be used as a very sensitive method to clearly differentiate these two clinically distinct DM subgroups. Using the nCounter PanCancer Immune Profiling Panel™, we identified a set of significantly dysregulated genes in anti‐TIF‐1γ+ patient muscle biopsies including VEGFA, DDX58, IFNB1, CCL5, IL12RB2, and CD84. Investigation of type I IFN‐regulated transcripts revealed a striking type I interferon signature in anti‐Mi‐2+ patient biopsies. Our results help to stratify both subgroups and predict, which DM patients require an intensified diagnostic procedure and might have a poorer outcome. Potentially, this could also have implications for the therapeutic approach. [ABSTRACT FROM AUTHOR]

Cats, similar to humans, are known to be affected by hippocampal sclerosis (HS), potentially causing antiepileptic drug (AED) resistance. HS can occur as a consequence of chronic seizure activity, trauma, inflammation, or even as a primary disease. In humans, temporal lobe resection is the standardized therapy in patients with refractory temporal lobe epilepsy (TLE). The majority of TLE patients are seizure free after surgery. Therefore, the purpose of this prospective cadaveric study is to establish a surgical technique for hippocampal resection in cats as a treatment for AED resistant seizures. Ten cats of different head morphology were examined. Pre-surgical magnetic resonance imaging (MRI) and computed tomography (CT) studies of the animals' head were carried out to complete 3D reconstruction of the head, brain, and hippocampus. The resected hippocampal specimens and the brains were histologically examined for tissue injury adjacent to the hippocampus. The feasibility of the procedure, as well as the usability of the removed specimen for histopathological examination, was assessed. Moreover, a micro-CT (mCT) examination of the brain of two additional cats was performed in order to assess temporal vasculature as a reason for possible intraoperative complications. In all cats but one, the resection of the temporal cortex and the hippocampus were successful without any evidence of traumatic or vascular lesions in the surrounding neurovascular structures. In one cat, the presence of mechanical damage (a fissure) of the thalamic surface was evident in the histopathologic examination of the brain post-resection. All hippocampal fields and the dentate gyrus were identified in the majority of the cats via histological examination. The study describes a new surgical approach (partial temporal cortico-hippocampectomy) offering a potential treatment for cats with clinical and diagnostic evidence of temporal epilepsy which do not respond adequately to the medical therapy. [ABSTRACT FROM AUTHOR]

Introduction: Small fiber neuropathies (SFN) are associated with a reduction in quality of life. In adults, epidermal nerve fiber density (END) analysis is recommended for the diagnosis of SFN. In children, END assessment is not often performed. We analyzed small nerve fiber innervation to elucidate the potential diagnostic role of skin biopsies in young patients with pain.Methods: Epidermal nerve fiber density and sudomotor neurite density (SND) were assessed in skin biopsies from 26 patients aged 7 to 20 years (15 female patients) with unexplained chronic pain. The results were compared with clinical data.Results: Epidermal nerve fiber density was abnormal in 50% and borderline in 35% of patients. An underlying medical condition was found in 42% of patients, including metabolic, autoimmune, and genetic disorders.Discussion: Reduction of epidermal nerve fibers can be associated with treatable conditions. Therefore, the analysis of END in children with pain may help to uncover a possible cause and guide potential treatment options. [ABSTRACT FROM AUTHOR]

Mass spectrometric analysis of glioblastoma cyst fluids has disclosed a protein peak with m/z 6424–6433. Among the proteins, potentially generating this peak are ApoC1 and LuzP6. To further elucidate protein expression of glioblastoma cells, we analyzed MALDI–TOF results of cyst fluid, performed immunohistochemistry and mRNA analysis. MALDI–TOF protein extraction from 24 glioblastoma cyst fluids was performed with a weak cation exchange. 50 glioblastoma samples were stained with two custom-made antibodies against LuzP6 and commercial antibodies against ApoC1, C12orf75 and OCC-1 and analyzed. For mRNA detection, 16 tissue samples were stored in RNAlater, extracted using the miRNeasy kit and reversely transcribed. For 12 patients, synopsis of results from all three examinations was possible. MALDI–TOF confirmed the peak at 6433 Da in 75% of samples. Immunohistochemically, LuzP6 was detected in 92% (LuzP61–29) and 96% (LuzP630–58) of samples and ApoC1 in 66%. Mean mRNA levels were highest for ApoC1, followed by LuzP6. No correlation between mRNA expression, immunohistochemical staining and intensity of the MALDI–TOF peaks was found. An unequivocal identification of one protein as the source for the 6433 peak is not possible, but our results point to ApoC1 and LuzP6 as the underlying proteins. [ABSTRACT FROM AUTHOR]

• Weakness of the feet dorsiflexors can evolve in IOPD after long-term ERT. • This distal weakness is due to progression of the myopathy. • A neuropathy in IOPD constitutes a further symptom that may evolve despite ERT. Enzyme replacement therapy in infantile onset Pompe disease has led to a new phenotype with features not known in the pre-enzyme replacement therapy era. We investigated the origin of a rapidly emerging and severe weakness of the foot dorsiflexors in a 7-year-old boy after 6.5 years of enzyme replacement therapy. Electroneurography yielded normal findings except low compound muscle action potentials of the extensor digitorum brevis muscles after stimulation of the peroneal nerves. Electromyography of the tibial muscle demonstrated a myopathic pattern. Tibial muscle, sural nerve, and skin biopsy showed a myopathy with empty and glycogen containing vacuoles, a mild loss of myelinated and unmyelinated axons, and a moderately reduced intraepidermal nerve fiber density. These findings provide evidence for a severe distal muscle involvement and a mild sensory neuropathy evolving during the course of disease after long-term enzyme replacement therapy, thereby expanding the new emerging phenotype of infantile onset Pompe disease. [ABSTRACT FROM AUTHOR]