Muscle biopsy

BACKGROUND: Magnetic resonance (MRI) imaging of the skeletal muscles (muscle MRI for short) is increasingly being used in clinical routine for diagnosis and longitudinal assessment of muscle disorders. However, cross-centre standards for measurement protocol and radiological assessment are still lacking. OBJECTIVES: The aim of this expert recommendation is to present standards for the application and interpretation of muscle MRI in hereditary and inflammatory muscle disorders...

The cell membrane protein, dystroglycan, plays a crucial role in connecting the cytoskeleton of a variety of mammalian cells to the extracellular matrix. The α-subunit of dystroglycan (αDG) is characterized by a high level of glycosylation, including a unique O-mannosyl matriglycan. This specific glycosylation is essential for binding of αDG to extracellular matrix ligands effectively. A subset of muscular dystrophies, called dystroglycanopathies, are associated with aberrant, dysfunctional glycosylation of αDG...

BACKGROUND: Facioscapulohumeral muscular dystrophy is a hereditary progressive myopathy caused by aberrant expression of the transcription factor DUX4 in skeletal muscle. No approved disease-modifying treatments are available for this disorder. We aimed to assess the safety and efficacy of losmapimod (a small molecule that inhibits p38α MAPK, a regulator of DUX4 expression, and p38β MAPK) for the treatment of facioscapulohumeral muscular dystrophy. METHODS: We did a randomised, double-blind, placebo-controlled phase 2b trial at 17 neurology centres in Canada, France, Spain, and the USA...

Autophagy is essential for proteostasis, energetic balance, and cell defense and is a key pathway in aging. Identifying associations between autophagy gene expression patterns in skeletal muscle and physical performance outcomes would further our knowledge of mechanisms related with proteostasis and healthy aging. Muscle biopsies were obtained from participants in the Study of Muscle, Mobility, and Aging (SOMMA). For 575 participants, RNA was sequenced and expression of 281 genes related to autophagy regulation, mitophagy, and mTOR/upstream pathways was determined...

CASE PRESENTATION: A 61-year-old female was referred to our hospital with a neoplastic lesion in the duodenum. Computed tomography with contrast enhancement revealed a 10-mm tumor in the duodenum. Upper gastrointestinal endoscopy revealed a submucosal tumor-like lesion in the descending part of the duodenum. Endoscopic ultrasound revealed a well-defined hypoechoic tumor. Biopsy and immunohistochemical findings including negative Synaptophysin and Chromogranin A staining and positive Trypsin and BCL10 staining suggested a carcinoma with acinar cell differentiation...

A decrease in muscle mass and its functionality (strength, endurance, and insulin sensitivity) is one of the integral signs of aging. One of the triggers of aging is an increase in the production of mitochondrial reactive oxygen species. Our study was the first to examine age-dependent changes in the production of mitochondrial reactive oxygen species related to a decrease in the proportion of mitochondria-associated hexokinase-2 in human skeletal muscle. For this purpose, a biopsy was taken from m. vastus lateralis in 10 young healthy volunteers and 70 patients (26-85 years old) with long-term primary arthrosis of the knee/hip joint...

Dermatomyositis represents a rare inflammatory myopathy that induces inflammation in the muscles or related tissues, including the blood vessels supplying these muscles. The precise pathogenesis of this condition remains unknown. Diagnosis typically relies on clinical indicators such as skin rashes, progressive muscle weakness, elevated serum muscle enzymes, abnormal electromyogram results, and muscle biopsy. In this case study, we report a fatal case of dermatomyositis in a 23-year-old female patient who succumbed to complications of dermatomyositis, causing mortality without any evidence of malignancy...

Dermatomyositis (DM) is an inflammatory myopathy often paraneoplastic in nature. Patients have characteristic cutaneous findings and possible muscle involvement. In the latter, muscle enzymes are elevated, and the electromyogram shows varied changes. Muscle or skin biopsy and myositis-specific antibodies confirm the diagnosis. Here, we report the case of an 86-year-old woman with cutaneous lesions, proximal weakness, and sicca symptoms. Muscle enzymes and electromyogram were normal. Antinuclear antibodies were elevated, and anti-TIF1γ and anti-Ro52 antibodies were positive...

We report an interesting case of skeletal muscle metastasis from lung cancer. Skeletal muscle metastasis is an unusual clinical occurrence and therefore lacks a standardized treatment approach. A 60-year-old female patient initially presented with abdominal pain and was found to have right lung consolidation, two hepatic lesions, and a lesion to the sartorius muscle. Initially treated as pneumonia, questions arose as to the lesion to the liver as well as the sartorius muscle. The primary site of malignancy was initially questioned due to the large size of the two hepatic lesions, with differential diagnoses including lung or hepatic origin...

UNLABELLED: TAR DNA-binding protein 43 (TDP-43) is an RNA binding protein that accumulates as aggregates in the central nervous system of some neurodegenerative diseases. However, TDP-43 aggregation is also a sensitive and specific pathologic feature found in a family of degenerative muscle diseases termed inclusion body myopathy (IBM). TDP-43 aggregates from ALS and FTD brain lysates may serve as self-templating aggregate seeds in vitro and in vivo, supporting a prion-like spread from cell to cell...

BACKGROUND: One of the limiting factors for vascularized composite allograft (VCA) storage is the short viable ischemic time (4-6 hours). Hypothermic machine perfusion (MP) enables near-physiological preservation, avoiding the deleterious effects of hypoxia and static cooling. This study aims to compare muscle injury after 24-hour acellular perfusion with static cold storage (SCS) in a porcine limb replantation model, examining outcomes for up to 7 days after reperfusion. METHODS: Sixteen procured porcine forelimbs were perfused hypothermic for 24 hours with Histidine-Tryptophan-Ketoglutarate (HTK, n=8) or preserved on ice for 4 hours (SCS, n=8) before orthotopic replantation...

INTRODUCTION: Placenta-associated pregnancy complications, including pre-eclampsia (PE) and intrauterine growth restriction (IUGR) are conditions postulated to originate from initial failure of placentation, leading to clinical sequelae indicative of endothelial dysfunction. Vascular smooth muscle aberrations have also been implicated in the pathogenesis of both disorders via smooth muscle contractility and relaxation mediated by Myosin Light Chain Phosphatase (MLCP) and the oppositional contractile action of Myosin Light Chain Kinase...

Bladder cancer (BC) is one of the most common malignancies in the United States, with over 80,000 new cases and 16,000 deaths each year. Urothelial carcinoma (UC) is the most common histology and accounts for 90% of cases. BC management is complicated by recurrence rates of over 50% in both muscle-invasive and non-muscle-invasive bladder cancer. As such, the American Urological Association (AUA) recommends that patients undergo close surveillance during and after treatment. This surveillance is in the form of cystoscopy or imaging tests, which can be invasive and costly tests...

INTRODUCTION: Idiopathic inflammatory myopathies (IIMs) encompass a diverse group of diseases characterized by considerable variability in clinical manifestations, antibody profiles, and responsiveness to immunosuppressive therapies. This study aimed to investigate the association between organ involvement and distinct myositis autoantibodies in individuals with IIM in a single-center cohort. METHODS: Patients with ICD diagnoses M33.1, M33.2, M33.9, or M609 who (1) had been tested with Euroline blot assay for myositis autoantibodies and (2) met the classification criteria of definite/probable polymyositis (PM) or dermatomyositis (DM), anti-synthetase syndrome (ASS), or inclusion body myositis (IBM) were included...

The STRAT-PARK initiative aims to provide a platform for stratifying Parkinson's disease (PD) into biological subtypes, using a bottom-up, multidisciplinary biomarker-based and data-driven approach. PD is a heterogeneous entity, exhibiting high interindividual clinicopathological variability. This diversity suggests that PD may encompass multiple distinct biological entities, each driven by different molecular mechanisms. Molecular stratification and identification of disease subtypes is therefore a key priority for understanding and treating PD...

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease, pathologically characterized by TDP-43 aggregates. Recent evidence has been indicated that phosphorylated TDP-43 (pTDP-43) is present not only in motor neurons but also in muscle tissues. However, it is unclear whether testing pTDP-43 aggregation in muscle tissue would assist in the diagnosis of ALS. We propose three key questions: (i) Is aggregation of pTDP-43 detectable in routine biopsied muscles? (ii) Can detection of pTDP-43 aggregation discriminate between ALS and non-ALS patients? (iii) Can pTDP-43 aggregation be observed in the early stages of ALS? We conducted a diagnostic study comprising 2 groups: an ALS group in which 18 cases underwent muscle biopsy screened from a registered ALS cohort consisting of 802 patients and a non-ALS control group, in which we randomly selected 54 muscle samples from a biospecimen bank of 684 patients...

Introduction Rhabdomyosarcoma, though rare in the middle ear, necessitates prompt recognition for optimal management. They are malignant mesenchymal neoplasms arising from the embryonic mesenchymal cells of striated skeletal muscles. Case presentation We present a case of a 5-year-old child with massive right mastoid swelling and bloody ear discharge. Cytological examination via fine needle aspiration biopsy revealed features suggestive of a malignant mesenchymal tumor, confirmed on imaging and subsequent histopathology as embryonal rhabdomyosarcoma (ERMS) FNCLCC grade 2...

Kearns-Sayre syndrome (KSS) is a rare mitochondrial disease that affects young adults, due to a deletion of mitochondrial DNA and characterized by the triad: age of onset lower than 20 years, chronic progressive external ophthalmoplegia, and an atypical pigmentary retinopathy. It is also characterized by other endocrine, neurological, and especially cardiac impairment with a very high risk of cardiac complications during surgical procedures under all types of anesthesia. We report a case of KSS revealed by severe bilateral ptosis and confirmed by a muscle biopsy with "ragged red fibers...

This report describes the cytologic features of a recently described MXD4::NUTM1-rearranged colonic sarcoma metastatic to the midclavicular soft tissue. Thirteen years ago, a 65-year-old woman presented with a cecal mass and subsequent liver mass. The cecal mass was diagnosed as malignant undifferentiated spindled and epithelioid neoplasm based on morphology and lack of tumor immunoreactivity with a panel of epithelial, smooth muscle, skeletal, melanoma, hematologic, and GIST markers. The liver mass showed morphologic and immunophenotypic similarity to the epithelioid component of the patient's cecal mass, albeit devoid of the spindled component...

The asymptote (critical power; CP) and curvature constant (W') of the hyperbolic power-duration relationship can predict performance within the severe-intensity exercise domain. However, the extent to which these parameters relate to skeletal muscle mitochondrial content and respiratory function is not known. Fifteen males (peak O2 uptake, 52.2 ± 8.7 mL kg-1  min-1 ; peak work rate, 366 ± 40 W; and gas exchange threshold, 162 ± 41 W) performed three to five constant-load tests to task failure for the determination of CP (246 ± 44 W) and W' (18...