AB0135 LEVELS OF MYOKINES AND RADIOGRAPHIC PROGRESSION IN PATIENTS WITH RHEUMATOID ARTHRITIS
Authors: Jordana Miranda de Souza Silva, Rafaela Cavalheiro Do Espírito Santo, Deborah Negrão Gonçalo Dias, Nayara Felicidade Thomas Braz, Érica Leandro Marciano Vieira, Eduarda Freitas, Rafael Mendonça Da Silva Chakr, Adriana Maria Kakehasi, Ricardo Xavier
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Myokines, such as irisin and myostatin, are cytokines and growth factors mainly expressed in skeletal muscle, which is also their primary target tissue. They are released into circulation and exert a variety of systemic effects promoting crosstalk among different tissues [1]. Irisin is known to retrieve disuse-induced bone loss by stimulating the osteoblast pathways, while myostatin was demonstrated to be highly expressed in the synovial tissues of rheumatoid arthritis (RA) subjects, with direct role in osteoclastogenesis [2, 3]. <h3>Objectives:</h3> To investigate whether myokines serum levels can predict one-year radiographic progression in patients with RA. <h3>Methods:</h3> Forty female patients with RA, according to ACR/EULAR 2010 classification criteria, were included in the study. Blood samples were collected, and ELISA was used to measure serum levels of irisin and myostatin. Radiographs of hands and feet, taken within three months of the blood collection and a year later, were evaluated using the Sharp-van der Heijde (SvH) score to verify the one-year radiographic progression. The RA activity was assessed by disease activity score based on evaluation of 28 joints (DAS28-ESR). Statistical analysis included Mann-Whitney U test and Spearman correlation. A value of p&lt;0.05 was considered significant. <h3>Results:</h3> The mean age of RA patients was 53 years old, mean DAS28-ESR was 4.09, mean disease duration was 11.2 years and mean BMI was 27.33 kg/m<sup>2</sup>. The mean serum levels of irisin and myostatin were respectively 25.61 ± 8.25 ng/ml and 3011.28 ± 1271.11 pg/ml. Considering radiographic progression, the mean values of SvH score were 28.3 and 31.3 in the baseline and after one year, respectively, resulting in a mean ΔSvH of 3. Over one year, 89.2% of the patients presented radiographic progression (ΔSvH score &gt;0), and 10.8% presented rapid progression (ΔSvH score &gt;5). <h3>Conclusion:</h3> The serum levels of irisin and myostatin were not correlated with one-year radiographic progression. There was a tendency of increased myostatin levels in patients with rapid progression compared to patients with no progression. More studies are needed to investigate whether the myokine levels in the joint environment differ from the circulating concentration. <h3>References</h3> [1] Giudice J, et al. Muscle as a paracrine and endocrine organ. Curr Opin Pharmacol. 2017Jun;34:49-55. [2] Colaianni G, et al. The myokine Irisin increases cortical bone mass. Proc Natl Acad Sci U S A. 2015Sep29;112(39):12157-62. [3] Dankbar B, et al. Myostatin is a direct regulator of osteoclast differentiation and its inhibition reduces inflammatory joint destruction in mice. Nat Med. 2015Sep;21(9):1085-90. <h3>Acknowledgement:</h3> Fundo de Incentivo à Pesquisa e Eventos do Hospital de Clínicas de Porto Alegre Coordenação de Aperfeiçoamento de Pessoal de Nível Superior <h3>Disclosure of Interests:</h3> Jordana Miranda de Souza Silva: None declared, Rafaela Cavalheiro do Espírito Santo: None declared, Deborah Negrão Gonçalo Dias: None declared, Nayara Felicidade Thomas Braz: None declared, Érica Leandro Marciano Vieira: None declared, Eduarda Freitas: None declared, Rafael Mendonça da Silva Chakr: None declared, Adriana Maria Kakehasi: None declared, Ricardo Xavier Consultant for: Abbvie, Pfizer, Novartis, Janssen, Lilly, Roche