Muscle Fiber Degeneration Research Articles

Microbiota-Induced Radioprotection: A Novel Approach to Enhance Human Radioresistance with In-Situ Genetically Engineered Gut Bacteria

The high sensitivity of living organic forms to space radiation remains the critical issue during spaceflight, to which they will be chronically exposed during months of interplanetary or even decades of interstellar spaceflight. In the human body, all actively dividing and poorly differentiated cells are always close to being damaged by radiological or chemical agents. The chronic exposure to ionizing radiation primarily causes changes in blood counts and intestinal damage such as fibrosis, obliterative vasculitis, changes in the gut microbiota, and atrophy or degeneration of muscle fibers. The project “MISS: Microbiome Induced Space Suit” was presented at the Giant Jamboree of the International Genetically Engineered Machine Competition 2021, with the aim to investigate the ability of the novel microbiota-mediated approach to enhance human resistance to ionizing radiation. The key innovative part of the project was the idea to create a novel radioprotector delivery mechanism based on human gut microbiota with the function of outer membrane vesicles (OMVs) secretion. The project concept proposed the feasibility of genetically modifying the human microbiota in situ through the delivery of genetic constructs to the host’s crypts using silicon nanoparticles with chemically modified surfaces. In this perspective, we discuss the advances in modifying microbiota-mediated secretory activity as a promising approach for radioprotection and as an alternative to hormone therapy and other health conditions that currently require continuous drug administration. Future clinical trials of in situ methods to genetic engineering the crypt microbiota may pave the way for indirect regulation of human cells.

Comparative evaluation of the effects of deferiprone and/or resveratrol in alleviating iron overload-induced tongue injury in rats

Iron overload causes excessive iron deposition in extrahepatic organs, including the tongue. This study aims to compare the deferiprone and/or resveratrol treatments for the alleviation of iron overload-induced tongue injury in rats. Rats were divided into 6 groups: control group, iron-overloaded group, recovery group where rats were left to recover from iron overload, deferiprone-treated group, resveratrol-treated group, and combined deferiprone/resveratrol-treated group. Iron was administered for 4 weeks, while all treatment options were given for the subsequent 4 weeks. After 8 weeks, all rats were sacrificed; the serum iron profile was estimated, and the tongues were assessed by histopathological, tumour necrosis factor alpha (TNF-α) immunohistochemical, histomorphometric, and ultrastructural evaluations. Serum iron parameters were significantly increased in iron-overloaded rats and decreased to control levels only in the combined group. The iron-overloaded tongues demonstrated lost lingual papillae, coarse keratohyalin granules, vacuolated epithelial cells, degenerated muscle fibers, and congested blood vessels. Compared to the control rats, this group revealed a significant decrease in the epithelial layer thickness (550.7 vs. 763.4µm), papillae height (441.4 vs. 849.7µm), and myofiber diameter (58.5 vs. 98.6µm), and increased lamina propria thickness (305.1 vs. 176.8µm), fibrosis index (33.4 vs. 8.6%), and TNF-α immunoexpression (1.16 vs. 0.63 optical density). Additionally, the ultrastructure showed hyperkeratinized papillae, wide interpapillary spaces, flat fungiform papillae, and lost gustatory pores. All these parameters were improved in the recovery, deferiprone, and resveratrol groups to different degrees, while the combined deferiprone/resveratrol treatment was the best option.

Intragenic dystrophin (DMD) duplication variant in Entlebucher Mountain Dogs with Duchenne muscular dystrophy.

Muscular dystrophies represent a group of disorders characterized by progressive muscle degeneration and weakness. An important subgroup are the dystrophin-related muscular dystrophies caused by variants in the DMD gene. They can be divided into the more severe Duchenne muscular dystrophy and the milder Becker muscular dystrophy. Here, we characterize the clinical, histopathological and molecular genetic aspects of two male Entlebucher Mountain Dogs with clinical signs of muscular dystrophy. The two dogs presented with marked dysphagia starting at the age of several weeks and in the later course recognizable exercise intolerance with highly increased serum creatine kinase levels. Histopathological signs of a dystrophic myopathy represented by degeneration of muscle fibers and signs of regeneration were present. Whole genome sequencing of one affected dog identified an intragenic 8.6 kb duplication in the X-chromosomal DMD gene, c.7528-4048_7645 + 4450dup. No other protein-changing variants in candidate genes for muscular dystrophy were identified. The duplication includes exon 52 of DMD and is predicted to lead to a frameshift and truncation of 30% of the wild-type open reading frame. Genotyping of the whole family confirmed the presence of the mutant allele in both affected dogs and the unaffected dam. The correct co-segregation of the mutant allele in the affected family as well as knowledge from humans and other species suggest the identified DMD variant as the most likely candidate variant for the muscular dystrophy phenotype in the two investigated dogs.

Distribution of MRI-derived T2 values as a biomarker for in vivo rapid screening of phenotype severity in mdx mice

Background The pathology in Duchenne muscular dystrophy (DMD) is characterized by degenerating muscle fibers, inflammation, fibro-fatty infiltrate, and edema, and these pathological processes replace normal healthy muscle tissue. The mdx mouse model is one of the most commonly used preclinical models to study DMD. Mounting evidence has emerged illustrating that muscle disease progression varies considerably in mdx mice, with inter-animal differences as well as intra-muscular differences in pathology in individual mdx mice. This variation is important to consider when conducting assessments of drug efficacy and in longitudinal studies. We developed a magnetic resonance imaging (MRI) segmentation and analysis pipeline to rapidly and non-invasively measure the severity of muscle disease in mdx mice. Methods Wildtype and mdx mice were imaged with MRI and T2 maps were obtained axially across the hindlimbs. A neural network was trained to rapidly and semi-automatically segment the muscle tissue, and the distribution of resulting T2 values was analyzed. Interdecile range and Pearson Skew were identified as biomarkers to quickly and accurately estimate muscle disease severity in mice. Results The semiautomated segmentation tool reduced image processing time approximately tenfold. Measures of Pearson skew and interdecile range based on that segmentation were repeatable and reflected muscle disease severity in healthy wildtype and diseased mdx mice based on both qualitative observation of images and correlation with Evans blue dye uptake. Conclusion Use of this rapid, non-invasive, semi-automated MR image segmentation and analysis pipeline has the potential to transform preclinical studies, allowing for pre-screening of dystrophic mice prior to study enrollment to ensure more uniform muscle disease pathology across treatment groups, improving study outcomes.

Reduction of Mitochondrial Calcium Overload via MKT077-Induced Inhibition of Glucose-Regulated Protein 75 Alleviates Skeletal Muscle Pathology in Dystrophin-Deficient mdx Mice.

Duchenne muscular dystrophy is secondarily accompanied by Ca2+ excess in muscle fibers. Part of the Ca2+ accumulates in the mitochondria, contributing to the development of mitochondrial dysfunction and degeneration of muscles. In this work, we assessed the effect of intraperitoneal administration of rhodacyanine MKT077 (5 mg/kg/day), which is able to suppress glucose-regulated protein 75 (GRP75)-mediated Ca2+ transfer from the sarcoplasmic reticulum (SR) to mitochondria, on the Ca2+ overload of skeletal muscle mitochondria in dystrophin-deficient mdx mice and the concomitant mitochondrial dysfunction contributing to muscle pathology. MKT077 prevented Ca2+ overload of quadriceps mitochondria in mdx mice, reduced the intensity of oxidative stress, and improved mitochondrial ultrastructure, but had no effect on impaired oxidative phosphorylation. MKT077 eliminated quadriceps calcification and reduced the intensity of muscle fiber degeneration, fibrosis level, and normalized grip strength in mdx mice. However, we noted a negative effect of MKT077 on wild-type mice, expressed as a decrease in the efficiency of mitochondrial oxidative phosphorylation, SR stress development, ultrastructural disturbances in the quadriceps, and a reduction in animal endurance in the wire-hanging test. This paper discusses the impact of MKT077 modulation of mitochondrial dysfunction on the development of skeletal muscle pathology in mdx mice.

GGC repeat expansions in NOTCH2NLC cause uN2CpolyG cerebral amyloid angiopathy.

The expansion of GGC repeats within NOTCH2NLC leads to the translation of the uN2CpolyG protein, the primary pathogenic factor in neuronal intranuclear inclusion disease (NIID). This study aims to explore the deposition of uN2CpolyG as an amyloid in the vessel wall, leading to uN2CpolyG cerebral amyloid angiopathy (CAA)-related cerebral microbleeds (CMBs). A total of 97 patients with genetically confirmed NIID were enrolled in this study. We analyzed the presence of CMBs using susceptibility-weighted imaging sequences and compared general clinical information, cerebrovascular risk factors, stroke history, antiplatelet medication use, and MRI features between NIID patients with and without CMBs. We further performed hematoxylin and eosin (H&E), Perl's, Congo red, and Thioflavin S staining, ubiquitin, p62 and uN2CpolyG immunostaining on brain tissue obtained from four NIID patients. A total of 354 CMBs were detected among 41 patients with NIID, with nearly half located in the deep brain, one-third in the lobes, and approximately 20% in the infratentorial area. No significant differences in cerebrovascular disease risk factors or history of antiplatelet drug use were observed between patients with and without CMBs. However, patients with CMBs suffered a higher incidence of previous ischemic and hemorrhagic stroke events. This group also had a higher incidence of recent subcortical infarcts and a higher proportion of white matter lesions in the external capsule and temporal pole. Conversely, patients without CMBs showed higher detection of high signals at the corticomedullary junction on diffusion-weighted imaging and more pronounced brain atrophy. H&E staining showed blood vessel leakage and hemosiderin-laden macrophage clusters, and Prussian blue staining revealed brain tissue iron deposition. CMBs occurred more frequently in small vessels lacking intranuclear inclusions, and extensive degeneration of endothelial cells and smooth muscle fibres was observed mainly in vessels lacking inclusions. Congo red-positive amyloid deposition was observed in the cerebral vessels of NIID patients, with disordered filamentous fibres appearing under an electron microscope. Additionally, the co-localization of Thioflavin S-labeled amyloid and uN2CpolyG protein in the cerebral vascular walls of NIID patients further suggested that uN2CpolyG is the main pathogenic protein in this form of amyloid angiopathy. In conclusion, we reviewed patients with GGC repeat expansion of NOTCH2NLC from a novel perspective, providing initial clinical, neuroimaging, and pathological evidence suggesting that uN2CpolyG may contribute to a distinct type of CAA.

Muscle degeneration in aging Drosophila flies: the role of mechanical stress

Muscle wasting is a universal hallmark of aging which is displayed by a wide range of organisms, although the causes and mechanisms of this phenomenon are not fully understood. We used Drosophila to characterize the phenomenon of spontaneous muscle fiber degeneration (SMFD) during aging. We found that SMFD occurs across diverse types of somatic muscles, progresses with chronological age, and positively correlates with functional muscle decline. Data from vital dyes and morphological markers imply that degenerative fibers most likely die by necrosis. Mechanistically, SMFD is driven by the damage resulting from muscle contractions, and the nervous system may play a significant role in this process. Our quantitative model of SMFD assessment can be useful in identifying and validating novel genetic factors that influence aging-related muscle wasting.

Pharmacotherapy review and clinical, sub-clinical characteristics in limb-girdle muscular dystrophy

Aims: Review pharmacotherapy in limb-girdle muscular dystrophy and describe clinical, and subclinical characteristics in patients of limb-girdle muscular dystrophy (LGMD). Methods: A meta-analysis with data in PubMed, up to May 2023 on the pharmacotherapy of LGMD combined with a cross-sectional study. Patients were diagnosed with LGMD according to the European Neuromuscular Centre (ENMC) in 1995 at E and Bach Mai Hospitals, from December 2022 to May 2023. Results: 21 studies in pharmacotherapy were conducted, and treatment therapies (glucocorticoid, biological antibody, gene therapy) initially showed safety and some effectiveness in muscular strength. There are some potential gene therapies. The clinical characteristic of collected 15 patients with LGMD was high onset age (20.7±12.5 years), and prolonged diagnosis time (6.3±5.5 years). Most patients showed signs of muscle weakness and muscle atrophy (100 and 86.7%), waddling gait, and Gower’s sign (93.3%). 100% of patients had increased creatine kinase (CK) of 1648.5±2235.8 U/l. Most patients had normal inflammatory indexes. On muscular histopathology, the majority of patients had muscle fiber degeneration, hypertrophy, fibrous tissue invasion, and fat infiltration (86.7%). Conclusions: Treatment therapies in LGMD initially showed safety and some effectiveness in muscular strength; the gene therapies are promising. Clinically, all patients showed signs of muscle weakness in the limb-girdle, most of them showed muscle atrophy, waddling gait, Gowers’ sign, increased CK, negative inflammatory markers, and muscle fiber degeneration on histopathology.

Novel Antiarrhythmic and Cardioprotective Effects of Brilliant Blue G

In this study, we investigated the effects of the purinergic P2X7 receptor antagonist brilliant blue G (BBG) on cardiac arrhythmia and myocardial injury induced by intravenously (i.v.) administered epinephrine in anesthetized rats. We also examined the possible involvement of beta-adrenergic receptors or cholinergic mechanisms in the effects of BBG. Sprague-Dawley rats were treated with epinephrine (10 μg/kg, i.v.). Brilliant blue G (100 mg/kg) was intraperitoneally (i.p.) administered thirty minutes prior to i.v. epinephrine. The effects of pretreatment with propranolol (2 mg/kg, i.p.) or atropine (2 mg/kg, i.v.) given prior to BBG and epinephrine were examined. The control group received saline. Moreover, the effects of only BBG on electrocardiogram (ECG) parameters were investigated. Results showed that compared with the saline control, BBG caused significant bradycardia (from 405.8 ± 1.18 to 239.4 ± 6.69 beats/min), increased RR interval (from 0.149 ± 0.002 to 0.254± 0.007 sec) and PR interval (from 0.051 ± 0.0008 to 0.059 ± 0.0004 sec), increased R wave amplitude (from 0.238 ± 0.019 to 0.548 ± 0.009 mv), and shortened QTc interval (from 0.169 ± 0.006 to 0.141 ± 0.003 sec) over 15 minutes after of BBG administration. BBG did not cause cardiac arrhythmia. Meanwhile, epinephrine produced significant bradycardia (209.8 ± 28.78 vs. 405.8 ± 1.18 beats/min), increased PR interval, prolonged the QRS complex, shortened QTc interval, decreased R wave amplitude and induced ventricular tachycardia. Brilliant blue G given prior to epinephrine increased heart rate and completely suppressed the epinephrine-induced ventricular arrhythmia. The inhibitory effect of BBG on the arrhythmia caused by epinephrine was prevented by atropine. In contrast the epinephrine induced arrhythmia was completely suppressed with propranolol and BBG. The histopathological study showed that epinephrine caused necrosis and apoptosis of cardiac muscle cells, degeneration of cardiac muscle fibers, and interstitial haemorrhages. These changes were markedly prevented by BBG alone, propranolol/BBG and to a less extent by atropine/BBG pretreatment. The study provided the first evidence for a cardioprotective and anti-arrhythmogenic actions for BBG against epinephrine-induced arrhythmia and myocardial damage, and suggested that cholinergic mechanisms are involved in its anti-arrhythmogenic action.

The ameliorative role of germinated fenugreek and barley grains on the structure and function of offspring’s tibialis muscle maternally fed on high fat diet

ABSTRACT This research demonstrates the impact of maternal high fat diet (HFD) consumption on the structure and function of the rat offspring tibialis muscle and investigates the protective potential of germinating fenugreek (Trigonella arabica) and barley (Hordeum vulgare) grains. Immunohistochemical analysis was performed on four distinct groups (HFD, HFD with fenugreek, HFD with barley and control group). Results revealed adverse effects on tibialis muscle and beneficial microbia in the intestine of offspring of HFD group. There were fluctuations in the levels of biochemical markers indicating potential implications for physiological processes within tibialis muscle. Lipid peroxidation and apoptotic factor caspase3 were increased in HFD group, while antioxidants in tibialis muscle were decreased along with increased levels of cholesterol, triglycerides and insulin resistance in serum. HFD induced inflammatory cells and degenerated muscle fibers with accumulated fat droplets and atrophied mitochondria. Dietary supplementation of either germinating barley and fenugreek grains showed modulatory improvement in antioxidant capacity, lipid peroxidation and apoptotic activity in both muscle fibers. These findings highlight the significance of dietary interventions, especially the inclusion of natural grains, in mitigating negative health outcomes in offspring due to maternal HFD consumption.

Protection by L-arginine against Epinephrine-induced Arrhythmia and Cardiotoxicity

Nitric oxide is important in control of coronary blood flow, cardiomyocyte contractility, cardiac rhythm, and thrombogenicity. We aimed to investigate the effect of the nitric oxide precursor L-arginine on cardiac arrhythmia and myocardial injury induced by epinephrine in male Sprague-Dawley rats. The possible modulation of L-arginine effects by methylene blue (MethyB), a nitric oxide synthase inhibitor was also examined. Cardiac arrhythmia was induced with 10μg/kg epinephrine given intravenously (i.v.). L-arginine (200mg/kg) or L-arginine and MethyB (100mg/kg) were intraperitoneally (i.p.) administered prior to i.v. epinephrine. Other groups received i.p. saline, only L-arginine or only MethyB (100mg/kg). Results showed that compared with the saline control, epinephrine caused a significant bradycardia (188.7±24.4 vs. 405.6±1.19beats/min), increased QRS duration (0.039±0.006 vs. 0.0185±0.0001s), decreased R wave amplitude (0.18±0.01 vs. 0.23±0.011mv), and ventricular extrasystoles. L-arginine alone showed no significant effect on heart rate (380.8±10.0 vs. 405.6±1.19beats/min) but increased QRS duration (0.029±0.0002 vs. 0.0185±0.0001s), and R wave amplitude (0.47±0.01 vs. 0.23±0.011mv). L-arginine given prior to epinephrine prevented bradycardia, shortened the duration of arrhythmia and decreased the number of extrasystoles. The administration of L-arginine and MethyB almost completely suppressed epinephrine-induced ventricular arrhythmias. Epinephrine caused severe degeneration of muscle fibres, widening of intercellular spaces, cellular infiltrations and interstitial haemorrhage. L-arginine markedly attenuated, while L-arginine/MethyB completely prevented these changes. It is concluded that L-arginine protects against cardiac arrhythmias and cardiac tissue damage caused by epinephrine.

Cyclo His-Pro Attenuates Muscle Degeneration in Murine Myopathy Models.

Among the inherited myopathies, a group of muscular disorders characterized by structural and metabolic impairments in skeletal muscle, Duchenne muscular dystrophy (DMD) stands out for its devastating progression. DMD pathogenesis is driven by the progressive degeneration of muscle fibers, resulting in inflammation and fibrosis that ultimately affect the overall muscle biomechanics. At the opposite end of the spectrum of muscle diseases, age-related sarcopenia is a common condition that affects an increasing proportion of the elderly. Although characterized by different pathological mechanisms, DMD and sarcopenia share the development of progressive muscle weakness and tissue inflammation. Here, the therapeutic effects of Cyclo Histidine-Proline (CHP) against DMD and sarcopenia are evaluated. In the mdx mouse model of DMD, it is shown that CHP restored muscle contractility and force production, accompanied by the reduction of fibrosis and inflammation in skeletal muscle. CHP furthermore prevented the development of cardiomyopathy and fibrosis in the diaphragm, the two leading causes of death for DMD patients. CHP also attenuated muscle atrophy and functional deterioration in a mouse model of age-related sarcopenia. These findings from two different models of muscle dysfunction hence warrant further investigation into the effects of CHP on muscle pathologies in animal models and eventually in patients.

Neuromuscular Junction Remodeling: the Role of Sub-Synaptic Nuclei, Terminal Schwann Cells, and Trophic Signaling Following Neuromusculoskeletal Injuries

Peripheral nerve crush injury is a well-established model of neuromuscular junction (NMJ) denervation and subsequent re-innervation. Functionally, the muscle tissue follows a similar pattern as neural recovery, with immediate loss of force production that steadily improves in parallel with rates of re-innervation. On the other hand, traumatic injury to the muscle tissue itself, specifically volumetric muscle loss (VML), results in an irrecoverable loss of muscle function. Recent work has indicated significant impairments to the NMJ following VML that appear chronic in nature, alongside functional recovery. Thus, the goal of this study was to compare the effects of nerve and muscle injury on NMJ remodeling, with the hypothesis that VML will result in chronic alterations to the NMJ, including a higher degree of cellular localization to the NMJ. Even numbers of adult male and female mice were used with three experimental groups: injury naive, nerve crush, and VML-injury; and three terminal timepoints: 3-, 48-, and 112-days post injury. Data were analyzed by three-way ANOVA with Tukey’s HSD post-hoc. Confirming the assumed recoverability of the two injury models, we found in vivo maximal torque was fully restored following nerve crush injury (Tukey’s HSD post hoc p=0.730), but remained at a significant deficit following VML (~41% lower than injury naïve; Tukey’s HSD post hoc p<0.001). Compared to nerve crush and injury naïve, we found VML results in aberrantly high trophic signaling and numbers of supporting cells. Protein expression of neuregulin-1 and connective tissue growth factor were both highest in the VML group (~1.2-fold and 12-fold increase compared to injury naïve, respectively; Main effect of group, p<0.001). While nerve crush injury elicited a transient increase in terminal Schwann cell numbers (~38% higher than injury naïve at 48dpi; Tukey’s HSD post hoc p<0.001), VML resulted in a chronic increase (~53% and 27% higher than injury naïve at 48 and 112dpi, respectively; Tukey’s HSD post hoc p<0.001). Moreover, nerve crush injury did not alter the number of sub-synaptic nuclei per NMJ, while VML resulted in significant increases at both 48- and 112-days post injury (~27% and 24% higher than injury naïve, respectively; Tukey’s HSD post hoc p=0.002). In some cases, sex differences were detected, including higher rates of innervation in females than males (Main effect of sex p=0.003), particularly following VML-injury (Tukey’s HSD post hoc p=0.004). The findings herein bear a striking resemblance to NMJs found in dystrophic muscle, which are thought to be the result of continuous cycles of muscle fiber degeneration and regeneration. Thus, the NMJ changes observed following VML may be indicative of a larger issue, such as chronic muscle fiber remodeling and pervasive fibrotic accumulation. R01-AR078903 (JAC & SMG); K02-AG081488 (SMG). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Diaphragm weakness in late-onset Pompe disease: A complex interplay between lower motor neuron and muscle fibre degeneration

BackgroundLate-onset Pompe disease (LOPD) patients may still need ventilation support at some point of their disease course, despite regular recombinant human alglucosidase alfa treatment. This suggest that other pathophysiological mechanisms than muscle fibre lesion can contribute to the respiratory failure process. We investigate through neurophysiology whether spinal phrenic motor neuron dysfunction could contribute to diaphragm weakness in LOPD patients. Material and methodsA group of symptomatic LOPD patients were prospectively studied in our centre from January 2022 to April 2023. We collected both demographic and clinical data, as well as neurophysiological parameters. Phrenic nerve conduction studies and needle EMG sampling of the diaphragm were perfomed. ResultsEight treated LOPD patients (3 males, 37.5%) were investigated. Three patients (37.5%) with no respiratory involvement had normal phrenic nerve motor responses [median phrenic compound muscle action potential (CMAP) amplitude of 0.49 mV; 1st-3rd interquartile range (IQR), 0.48–0.65]. Those with respiratory failure (under nocturnal non-invasive ventilation) had abnormal phrenic nerve motor responses (median phrenic CMAP amplitude of 0 mV; 1st-3rd IQR, 0–0.15), and were then investigated with EMG. Diaphragm needle EMG revealed both myopathic and neurogenic changes in 3 (60%) and myopathic potentials in 1 patient. In the last one, no motor unit potentials could be recruited. ConclusionsOur study provide new insights regarding respiratory mechanisms in LOPD, suggesting a contribution of spinal phrenic motor neuron dysfunction for diaphragm weakness. If confirmed in further studies, our results recommend the need of new drugs crossing the blood-brain barrier.

Pathological findings with vacuoles in anti-mitochondrial antibody-positive inflammatory myopathy

BackgroundA few patients with inflammatory myopathy showed anti-mitochondrial antibody (AMA) positivity. This study aimed to report the clinical and pathological findings with vacuoles in 3 cases of such patients.MethodsThree cases with myositis from the Myositis Clinical Database of Peking University First Hospital were identified with AMA positivity. Their clinical records were retrospectively reviewed and the data was extracted. All the 3 cases underwent muscle biopsy.ResultsThree middle-aged patients presented with chronic-onset weakness of proximal limbs, marked elevation of creatine kinase, and AMA-positivity. Two of the 3 cases meet the criteria of primary biliary cholangitis. All the 3 cases presented with cardiac involvement and proteinuria. Two cases developed type 2 respiratory failure. MRI of the thigh muscle showed multiple patches of edema bilaterally in both cases, mostly in the adductor magnus. Pathological findings include degeneration of muscle fibers, diffused MHC-I positivity, and complement deposits on cell membranes. Vacuoles without rims of different sizes were discovered under the membrane of the muscle fibers. A few RBFs were discovered in case 1, while a diffused proliferation of endomysium and perimysium was shown in case 2.ConclusionsAMA-positive inflammatory myopathy is a disease that could affect multiple systems. Apart from inflammatory changes, the pathological findings of muscle can also present vacuoles.

Effects of sevoflurane and fullerenol C60 on lower limb ischemia-reperfusion injury in streptozocin-induced diabetic mice.

Ischemia-reperfusion injury (IRI) poses a significant challenge for physicians, necessitating the management of cell damage and the preservation of organ functions. Various surgical procedures, such as vascular surgery on extremities, temporary cross-clamping of the abdominal aorta in aortic surgery, and the use of a tourniquet in extremity surgeries, may induce lower limb IRI. The susceptibility to IRI is heightened in individuals with diabetes. This study aimed to investigate the effects of fullerenol C60 and sevoflurane on mouse muscle tissue in a lower limb IRI model and to assess their potential in preventing complications arising from ischemia-reperfusion in mice with streptozocin-induced diabetes. A total of 36 adult Swiss albino mice were randomly divided into six groups, each consisting of six mice: control group (group C), diabetes group (group D), diabetes-ischemia/reperfusion group (group DIR), diabetes-ischemia/reperfusion-fullerenol C60 group (group DIR-FC60), diabetes-ischemia/reperfusion-sevoflurane group (group DIR-S), and diabetes-ischemia/reperfusion-sevoflurane-fullerenol C60 group (DIR-S-FC60). Streptozocin (55 mg/kg) was intraperitoneally administered to induce diabetes in the relevant groups, with mice displaying blood glucose levels of 250 mg/dL or higher at 72 h were considered diabetic. After 4 weeks, all groups underwent laparotomy under anesthesia. In DIR-FC60 and DIR-S-FC60 groups, fullerenol C60 (100 mg/kg) was intraperitoneally administrated 30 min before the ischemia period. Sevoflurane, delivered in 100% oxygen at a rate of 2.3% and 4 L/min, was administered during the ischemia period in DIR-S and DIR-S-FC60 groups. In the IR groups, a microvascular clamp was placed on the infrarenal abdominal aorta for 120 min during the ischemia period, followed by the removal of the clamp and a 120-min reperfusion period. At the end of the reperfusion, gastrocnemius muscle tissues were removed for histopathological and biochemical parameter examinations. Histopathological examination revealed a significant reduction in the disorganization and degeneration of muscle cells in the DIR-S-FC60 group compared to the DIR group (p = 0.041). Inflammatory cell infiltration was notably lower in the DIR-S, DIR-FC60, and DIR-S-FC60 groups than in the DIR group (p = 0.031, p = 0.011, and p = 0.013, respectively). The total damage scores in the DIR-FC60 and DIR-S-FC60 groups were significantly lower than in the DIR group (p = 0.018 and p = 0.008, respectively). Furthermore, the levels of malondialdehyde (MDA) in the DIR-S, DIR-FC60, and DIR-S-FC60 groups were significantly lower than in the DIR group (p < 0.001, p < 0.001, and p < 0.001, respectively). Catalase (CAT) enzyme activity in the DIR-S, DIR-FC60, and DIR-S-FC60 groups was higher than in the DIR group (p = 0.001, p = 0.014, and p < 0.001, respectively). Superoxide dismutase (SOD) enzyme activity in the DIR-FC60 and DIR-S-FC60 groups was also higher than in the DIR group (p < 0.001 and p = 0.001, respectively). Our findings indicate that administering fullerenol C60 30 min prior to ischemia in diabetic mice, in combination with sevoflurane, led to a reduction in oxidative stress and the correction of IR-related damage in muscle tissue histopathology. We believe that the administration of fullerenol C60 before IR, coupled with sevoflurane administration during IR, exerts a protective effect in mice.

Morphological study of incompetent saphenous veins: apoptosis and ultrastructural changes of smooth muscle cells.

Varicose veins affect approximately 25% of people in industrialized countries. The study aimed at detecting apoptotic cells and histopathological changes in varicose vein walls. Patients (N.=41) with varicose veins and 30 control group patients were divided into two groups according to their age (younger and older than 50 years). Apoptosis was determined by the TUNEL assay, elastin and collagen IV expression by immunohistochemistry and ultrastructural changes by transmission electron microscopy. The results show that the number of apoptotic cells in the layers of varicose veins increased, in particular in a group of patients aged over 50 years. In the varicose veins as compared to control veins the elastic fibers were found to be thinner, more fragmented and disorderly arranged. Elastin and collagen IV expression was found to decline in the intima and the media of varicose veins in both age groups. Electron microscopy demonstrated hypertrophy and degeneration of smooth muscle cells. Furthermore, cells with ultrastructural feature of apoptosis were noted. In the disorganized and expanded extracellular matrix membrane-bound vesicles, ghost bodies with different size and electron density were observed. Ghost bodies seem to bud off from smooth muscle cells and are likely to be involved in extracellular matrix remodeling as they are seen in close contact with collagen fibers. The study demonstrates increase of apoptotic cells in the wall of varicose veins along with vein wall structural abnormalities including alterations of smooth muscle cells and decline of elastin and collagen IV expression.

Mitochondria and Reactive Oxygen Species: The Therapeutic Balance of Powers for Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy (DMD) is a genetic progressive muscle-wasting disorder that leads to rapid loss of mobility and premature death. The absence of functional dystrophin in DMD patients reduces sarcolemma stiffness and increases contraction damage, triggering a cascade of events leading to muscle cell degeneration, chronic inflammation, and deposition of fibrotic and adipose tissue. Efforts in the last decade have led to the clinical approval of novel drugs for DMD that aim to restore dystrophin function. However, combination therapies able to restore dystrophin expression and target the myriad of cellular events found impaired in dystrophic muscle are desirable. Muscles are higher energy consumers susceptible to mitochondrial defects. Mitochondria generate a significant source of reactive oxygen species (ROS), and they are, in turn, sensitive to proper redox balance. In both DMD patients and animal models there is compelling evidence that mitochondrial impairments have a key role in the failure of energy homeostasis. Here, we highlighted the main aspects of mitochondrial dysfunction and oxidative stress in DMD and discussed the recent findings linked to mitochondria/ROS-targeted molecules as a therapeutic approach. In this respect, dual targeting of both mitochondria and redox homeostasis emerges as a potential clinical option in DMD.

Anti-SAE dermatomyositis: clinical and histologic characteristics from a monocentric Italian cohort.

Multiple myositis-specific antibodies have been identified, each associated with different clinical subsets of dermatomyositis (DM). Anti-SAE associated DM is considered the least studied subset. Our study aimed to evaluate the clinical and histological characteristics of DM patients with anti-SAE antibodies. As reference, patients with anti-Mi2 antibodies associated DM, representing a well-characterised subset, were analysed. We recorded data from our DM cohort in the INflammatory MYositis REgistry (INMYRE). Patients were divided into two groups: those positive for anti-SAE and those positive for anti-Mi2 antibodies. Clinical characteristics, including skin, muscle, and extra-muscular involvements, were recorded. Available muscle biopsies were compared between the two groups. Of 92 DM patients, 10 (10.9%) were positive for anti-SAE and 17 (18.5%) for anti-Mi2. Anti-SAE positive DM patients showed classic DM findings but were characterised by a higher prevalence of skin itching (60% vs. 11.8%, p<0.01), shawl sign (40% vs. 5.9%, p<0.05) and lung involvement (30% vs. 0%, p<0.05) compared to anti-Mi2 positive patients. Furthermore, anti-SAE positive DM patients showed lower creatine kinase levels than those with anti-Mi2 (median [IQR]: 101 [58-647] vs. 1984 [974-3717], p<0.05) and a lower percentage of muscle fibre degeneration and necrosis (1.5%±1.7 vs. 5.9%±3.2, p<0.05) in muscle biopsies. No other differences were observed. Anti-SAE DM represents a disease subset characterised by classic cutaneous involvement often associated with itching, less severe muscle involvement, but potential pulmonary involvement that should always be investigated in these patients.

Trilobatin contributes to the improvement of myopathy in a mouse model of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) occurs due to genetic mutations that lead to a deficiency in dystrophin production and consequent progressive degeneration of skeletal muscle fibres, through oxidative stress and an exacerbated inflammatory process. The flavonoid trilobatin (TLB) demonstrates antioxidant and anti-inflammatory potential. Its high safety profile and effective action make it a potent therapy for the process of dystrophic muscle myonecrosis. Thus, we sought to investigate the action of TLB on damage in a DMD model, the mdx mouse. Eight-week-old male animals were treated with 160 mg/kg/day of trilobatin for 8 weeks. Control animals were treated with saline. Following treatment, muscle strength, serum creatine kinase (CK) levels, histopathology (necrotic myofibres, regenerated fibres/central nuclei, Feret's diameter and inflammatory area) and the levels of catalase and NF-κB (western blotting) of the quadriceps (QUA), diaphragm (DIA) and tibialis anterior (TA) muscles were measured. TLB was able to significantly increase muscle strength and reduce serum CK levels in dystrophic animals. The QUA of mdx mice showed a reduction in catalase and the number of fibres with a centralized nucleus after treatment with TLB. In the DIA of dystrophic animals, TLB reduced the necrotic myofibres, inflammatory area and NF-κB and increased the number of regenerated fibres and the total fibre diameter. In TA, TLB increased the number of regenerated fibres and reduced catalase levels in these animals. It is concluded that in the mdx experimental model, treatment with TLB was beneficial in the treatment of DMD.