AB0086 NEW METHOD TO ASSESS SKELETAL MUSCLE ATROPHY IN COLLAGEN INDUCED ARTHRITIS (CIA) MODEL

Background:Muscle quality in rheumatoid arthritis (RA) is a new concept that involves morphological features and function. A measurement that associates cell morphology with clinical and physical parameters has not been reported in the literature. CIA is a RA mice model characterized by loss of muscle mass similar to human RA, thereby it is a convenient model to study the disease impact in muscle physiology.Objectives:Develop an index to measure the morphometry of muscle fibers and correlate the morphological features with the muscle functional performance in CIA.Methods:18 DBA/1J mice were induced using complete Freund’s adjuvant and a booster after 18 days induction. Along experimental phase, we evaluated muscle strength using grip strength test and clinical disease score after onset of disease. 16 healthy mice were used as control. After 25 days CIA induction, 8 CIA and 8 controls were euthanized for muscle evaluation in mild disease and, at day 50, 8 CIA and 8 control mice were euthanized for evaluation in severe disease. Tibialis anterior were collected for myofiber histological analysis. Using the Image Pro Plus software (Media Cybernetics, China), we segmented muscle fibers and assessed its area and its regularity (the last through an index named Muscle Fiber Irregularity Index, MFII). The index works as a threshold to set to screen the degree of normal, atrophic and hypertrophic based on the morphometry if muscle fibers. Values are compared to area and shape of control (healthy) fibers. Frequency analysis and Pearson Correlations were used and statistical significance was considered as p<0.05.Results:We found 1.5% atrophic muscle fibers in control animals. Mild CIA showed the same atrophic muscle fibers percentage compared to control. However, severe CIA showed 11.8% of atrophic muscle fibers. Decrease muscle strength in CIA over time were associated with a greater atrophic muscle fiber proportion (r=-0.8, p=0.021) and increased disease score (r=-0.8; p=0.019).Conclusion:Here we developed a new, objective method applied to screen for muscle quality through the morphometry of muscle fibers. Muscular Morphometric Analysis (MusMA) has potential to be used in combination with clinical parameters in several human pathophysiological analysis. Besides that, we can speculate that although muscle strength is associated with atrophic cell percentage, loss of strength does not only depend of atrophy, but disease activity also seems to influence muscle strength reduction.References:[1].Turesson C, Matterson EL. – Management of extra-articular disease manifestations in rheumatoid arthritis. Curr Opin Rheumatol. 2004; 16(3) 206-11[2]Mielants H, Van den Bosch 2. – Extra-articular manifestations. Clin Exp Rheumatology 2009; 27(Suppl. 55): S56-S61[3]Bouchard DR, Janssen I. Dynapenic-obesity and physical function in older adults. The journals of gerontology Series A, Biological sciences and medical sciences. 2010; 65(1):71–7.[4]MANINI, T. M.; CLARK, B. C. Dynapenia and aging: An update. Journals of Gerontology - Series A Biological Sciences and Medical Sciences, v. 67 A, n. 1, p. 28–40, 2012. ISSN 10795006. Citado na página 19.Disclosure of Interests:Bárbara Bartikoski: None declared, Jordana Miranda de Souza Silva: None declared, Eduardo Chiela: None declared, Ricardo Xavier Consultant of: AbbVie, Pfizer, Novartis, Janssen, Eli Lilly, Roche

Evaluation of the in vivo effect of argon plasma coagulation with prior submucosal injection (Hybrid APC) in the esophagus of pigs

Background Although argon-plasma coagulation (APC) is useful for treating early gastrointestinal cancer, safer ablation for oesophageal cancer is needed because the esophageal wall is very thin. The efficacy of APC with prior submucosal injection of saline (hybrid APC) by using a resected oesophagus of pig has been reported, but there has been no study in which the effects, biological reactions and delayed adverse effects of hybrid APC were evaluated. In this study, we evaluated the histological efficacy of APC with prior submucosal injection of saline (hybrid APC) by using an in vivo porcine model. Methods APC alone and hybrid APC were performed. Various settings of argon were used. The pigs were sacrificed after treatment (study 1) and 1 week after treatment (study 2). Histological evaluation of the deepest spot of coagulation from the basal layer (study 1) and non-atrophic muscle zone (study 2) in resected specimens was performed. Type A damage was defined as superficial tissue damage of the tunica mucosa, whereas type B damage was defined as an injury pattern limited to the tunica muscularis. The depths of type A and type B damage were measured in study 1. Immunohistochemical analysis was also performed in study 2. Results (study 1) Hybrid APC except for that at an excessive setting could prevent type B damage of the muscle layer. Standard APC at any setting could not prevent type B damage of the muscle layer. Results (study 2) The non-atrophic muscle zone was significantly larger in the hybrid APC group. Immunohistochemical analysis showed that the numbers of activated myofibroblasts and infiltrating neutrophils and macrophages were significantly smaller in the hybrid APC group than in the standard APC group. Conclusion APC following submucosal injection of saline contributes to sufficient and safe coagulation for oesophageal lesions.

Autophagy induction in atrophic muscle cells requires ULK1 activation by TRIM32 through unanchored K63-linked polyubiquitin chains

Optimal autophagic activity is crucial to maintain muscle integrity, with either reduced or excessive levels leading to specific myopathies. LGMD2H is a muscle dystrophy caused by mutations in the ubiquitin ligase TRIM32, whose function in muscles remains not fully understood. Here, we show that TRIM32 is required for the induction of muscle autophagy in atrophic conditions using both in vitro and in vivo mouse models. Trim32 inhibition results in a defective autophagy response to muscle atrophy, associated with increased ROS and MuRF1 levels. The proautophagic function of TRIM32 relies on its ability to bind the autophagy proteins AMBRA1 and ULK1 and stimulate ULK1 activity via unanchored K63-linked polyubiquitin. LGMD2H-causative mutations impair TRIM32’s ability to bind ULK1 and induce autophagy. Collectively, our study revealed a role for TRIM32 in the regulation of muscle autophagy in response to atrophic stimuli, uncovering a previously unidentified mechanism by which ubiquitin ligases activate autophagy regulators.

Quantitative Computed Tomography and image analysis for advanced muscle assessment

Medical imaging is of particular interest in the field of translational myology, as extant literature describes the utilization of a wide variety of techniques to non-invasively recapitulate and quantity various internal and external tissue morphologies. In the clinical context, medical imaging remains a vital tool for diagnostics and investigative assessment. This review outlines the results from several investigations on the use of computed tomography (CT) and image analysis techniques to assess muscle conditions and degenerative process due to aging or pathological conditions. Herein, we detail the acquisition of spiral CT images and the use of advanced image analysis tools to characterize muscles in 2D and 3D. Results from these studies recapitulate changes in tissue composition within muscles, as visualized by the association of tissue types to specified Hounsfield Unit (HU) values for fat, loose connective tissue or atrophic muscle, and normal muscle, including fascia and tendon. We show how results from these analyses can be presented as both average HU values and compositions with respect to total muscle volumes, demonstrating the reliability of these tools to monitor, assess and characterize muscle degeneration.

Severely atrophic human muscle fibers with nuclear misplacement survive many years of permanent denervation

Likewise in rodents, after complete spinal cord injury (SCI) the lower motor neuron (LMN) denervated human muscle fibers lose completely the myofibrillar apparatus and the coil distribution of myonuclei that are relocated in groups (nuclear clumps) in the center of severely atrophic muscle fibers. Up to two years of LMN denervation the muscle fibers with nuclear clumps are very seldom, but in this cohort of patients the severely atrophic muscle fibers are frequent in muscle biopsies harvested three to six years after SCI. Indeed, the percentage increased to 27 ± 9% (p&lt; 0.001), and then abruptly decreased from the 6th year onward, when fibrosis takes over to neurogenic muscle atrophy. Immunohistochemical analyses shown that nuclear misplacements occurred in both fast and slow muscle fibers. In conclusion, human muscle fibers survive permanent denervation much longer than generally accepted and relocation of nuclei is a general behavior in long term denervated muscle fibers.

Challenges of Preoperative Diagnosis and Management of Scalene Intramuscular Angioma

Intramuscular angioma of scalene muscle is rare with only five cases reported so far. Four of them have not been suspected before surgery; one was diagnosed preoperatively by core biopsy. Preoperative diagnosis is important for management. Awareness of cytologic features could help preoperative diagnosis when need of ruling out malignancy and coagulopathy make fine needle aspiration a choice. We herein demonstrate a new case of a 27 year old male with history of hepatocellular carcinoma, who presented with a 6 cm left supraclavicular mass. The fine needle aspiration was paucicellular; however, the bland ovoid to spindle cells with a whirling and luminal arrangement in the background of blood, fatty drops and degenerate muscle are suggestive of intramuscular angioma. The magnetic resonance imagines (MRI) demonstrate a T1 isointense and T2 hyperintense ill-defined lesion splaying anterior and mid scalene muscles with subtle vascular voids at periphery. These features in combination with cytology findings indicate intramuscular angioma. The pre-operative findings are correlated to the histologic picture of mixed capillaries and varying sized venues intervening with fatty tissue and atrophic muscle. Intraoperatively, the mass is adjacent to the brachial plexus rootlets, interdigitating with the scalene muscle and pushing the carotid sheath, left subclavicular artery and vein aside. Following embolization, the mass is resected with minimal bleeding. Our case suggests that scalene intramuscular angioma can be successfully managed by surgery after embolization; preoperative diagnosis rendered by cytologic features and imaging characters would aid the planning of surgery.