AB0304 Serum levels of sclerostin and DICKKOPF-1, and their correlation with bone mineral density and bone markers in rheumatoid arthritis
Authors: CA Nava-Valdivia, E Corona-Sanchez, J Ponce-Guarneros, A Saldaña-Cruz, J Murillo-Vazquez, E Perez-Guerrero, P Hernandez-Cuervo, M Salazar-Paramo, D Cardona-Müller, E Cardona-Muñoz, L Gonzalez-Lopez, J Gamez-Nava
Journal: Annals of the Rheumatic Diseases (2017)

<h3>Background</h3> Sclerostin (SOST) and dickkopf-1 (DKK1) are involved in the development of primary osteoporosis. Although to date, it is controverted does exist about if serum levels of these molecules may reflex adequately a subgroup of patients with decrement of Bone Mineral Density (BMD) being useful as clinical biomarkers. Some non-conclusive observations made in postmenopausal osteoporosis have shown abnormalities in serum levels. To date, there is a lack of information about if these serum molecules are associated with a decrease of BMD in RA. This information is relevant for to know if the measurement of these serum molecules could be useful in the clinical care to identify a subgroup of patients with low BMD. <h3>Objectives</h3> To evaluate if serum levels of SOST and DKK1 correlate with bone mineral density and other bone markers in RA. <h3>Methods</h3> In this Cross-sectional study, we included 115 women with RA &gt;40 years old. All patients were assessed for clinical characteristics disease activity (DAS28) and functioning (HAQ-Di). BMD was measured in lumbar spine, hip and forearm using DXA. According to their results, osteoporosis was identified if the BMD in a patient had a T-score with a decrement of ≤-2.5 standard deviation (SD). According to their results we classified these patients in two groups: a) low BMD (T-score≤-1SD on lumbar spine or total hip) and b)normal BMD (T-score&gt;-1SD). Serum SOST, DKK1, including serum Receptor Activator of NF-κB Ligand (sRANKL) and osteoprotegerin (OPG) were quantified by ELISA. We compared serum levels between the groups using Student t-tests. For comparisons between proportions we performed Chi-square test (or Fisher exact test if required). Correlations between serum levels of SOST, DKK1, with BMD, clinical variables, sRANKL and OPG we performed Pearson correlation tests. <h3>Results</h3> From the 115 women with RA, 58 patients had low BMD (50.4%), from them 44 patients (38.3%) had osteoporosis. Patients in the group with low BMD had higher age (63±8 vs 53±9,p&lt;0.0001), DAS28 (4.1±1.5 vs 3.3±1.4, p=0.011), and HAQ-Di score (0.69±0.53 vs 0.36±0.47, p=0.001) compared with normal BMD; whereas lower serum levels of sclerostin was observed in the low BMD group (128.5±75.0 vs 178.2±103.3, p=0.004). SOST levels were correlated with BMD in lumbar spine (r=0.393, p&lt;0.0001), hip (r=0.388,p&lt;0.0001) and forearm (r=0.319, p=0.001). sRANKL serum levels had a negative correlation with BMD in hip (r=-0.17, p=0.03). No correlations were observed between serum DKK1 and OPG with BMD in hip or lumbar spine. <h3>Conclusions</h3> These results indicate that SOST, and RANKL are biomarkers may associated with abnormal BMD in RA. Further long-term follow-up studies should evaluate if high levels of these serum biomarkers could be useful as tests to predict the future development of osteoporotic fractures. <h3>References</h3> Xu et al. Chin Med J. 2013;126:2480–84. Xu et al. Rheumatol Int. 2012;32:3397–403. <h3>Acknowledgements</h3> This project was supported by grant from the Fondo de Investigaciόn en Salud del Instituto Mexicano del Seguro Social: FIS/IMSS/PROT/GIS/1455. <h3>Disclosure of Interest</h3> C. Nava-Valdivia: None declared, E. Corona-Sanchez: None declared, J. Ponce-Guarneros: None declared, A. Saldaña-Cruz: None declared, J. Murillo-Vazquez: None declared, E. Perez-Guerrero: None declared, P. Hernandez-Cuervo: None declared, M. Salazar-Paramo: None declared, D. Cardona-Müller: None declared, E. Cardona-Muñoz: None declared, L. Gonzalez-Lopez Grant/research support from: Is a recipient of a Fundaciόn IMSS Scholarship, México., J. Gamez-Nava: None declared