Identification of a serum protein biomarker panel for the diagnosis of knee osteoarthritis

Abstract

s / Osteoarthritis and Cartilage 24 (2016) S8eS62 S23 knee criteria and included features related to osteophytes, cartilage damage, bone marrow lesions, subchondral cysts and labral lesions. Logistic regression analysis was used to evaluate the association of FAI with moderate cartilage damage ( 2), moderate BML ( 2) and MRI-OA. Analyses were adjusted for age, sex, body mass index and family history of OA and, in secondary analyses, also for physical activity. Results: Subjects in the MRI study (n 1⁄4 182) had mean age 43.5 years, mean BMI 26.8, mean WOMAC pain 14.4 and 65.4% were female. FAI was present in 48.9% and hip pain in 51.7%. Cartilage score 2, BML 2 and MRI-OA were present in 11.0%, 9.9% and 8.9%, respectively. FAI was not significantly associated with cartilage damage 2 (OR 2.0, 95% CI 0.7e5.5) and this relationship remained non-significant after adjustment for physical activity (OR 1.8, 95% CI 0.6e5.2). There was a statistically significant association of FAI with BML 2 (OR 4.7, 95% CI 1.4e16.0) and with MRI-OA (OR 3.4, 95% CI 1.1e12.3). Additional adjusting for physical activity did not change the findings for BML (OR 4.2, 95% CI 1.4e14.7) and MRI-OA (OR 2.9, 95% CI 0.9e10.6), although the latter was only of borderline statistical significance. Conclusions: In this population-based cross-sectional study of young adults, the risk of moderate BML and MRI-defined OA was significantly increased in subjects with radiographic FAI compared to those without radiographic FAI. No association was found for FAI with moderate cartilage damage. These findings suggest that FAI is linked to early osteoarthritic changes onMRI in young adults. Whether BML is a precursor to future cartilage damage and radiographic OA requires longitudinal evaluation of this cohort. 27 IDENTIFICATION OF A SERUM PROTEIN BIOMARKER PANEL FOR THE DIAGNOSIS OF KNEE OSTEOARTHRITIS L. Lourido y, B. Ayoglu z, J. Fern andez-Tajes x, F. Henjes z, J.M. Schwenk z, C. Ruiz-Romero y, P. Nilsson z, F.J. Blanco y. yRheumatology Div., ProteoRed/ISCIII Proteomics Group, INIBIC e Hospital Universitario de A Coru~ na, Spain; zAffinity Proteomics, SciLifeLab, Sch. of Biotechnology, KTH-Royal Institute of Technology, Stockholm, Sweden; xWellcome Trust Ctr. For Human Genetics, McCarthy's Group, University of Oxford, Oxford, United Kingdom Purpose: Osteoarthritis (OA) is the most common rheumatic disease. Despite the active research in the OA biomarker field, no single protein is sufficiently reliable for its use in OA diagnosis. This is mainly due to the lack of validation studies in large populations, making the findings questionable to be considered as robust biomarkers for the OA joint turnover. In this study we addressed a large-scale study with the aim of search for proteins that could serve as potential indicators of knee OA. Methods: Antibody suspension bead arrays were applied to profile serum samples from patients with knee OA (n 1⁄4 288) with different Kellgren-Lawrence (K/L) scores and compare to patients with rheumatoid arthritis (RA, n 1⁄4 288), psoriatic arthritis (PsA, n 1⁄4 288) and healthy control (n 1⁄4 96) subjects with non-radiographic knee osteoarthritis. The serum protein content was labelled and protein profiles obtained using 174 antibodies from the Human Protein Atlas targeting 78 different proteins. A focused bead array was then built to further profile 46 selected protein targets as a replication of the first findings and also to validate these results in an independent cohort of serum samples composed by patients with OA (n 1⁄4 196), RA (n 1⁄4 192), PsA (n1⁄4 192) and healthy control individuals (n1⁄4 92). The panel of proteins proposed and analysed for this study was selected based on previous internal protein profiling studies in the context of rheumatic diseases. For the statistical analysis, a lineal regression analysis adjusting by sex, age and body mass index (BMI) was applied to observe differences in protein profiles between compared groups and these were denoted statistically significant if they concordantly revealed p.values 2-fold increase in the risk of incident ROA, while sarcopenia alone had no increased risk, compared with those who were non-obese non-sarcopenic (Table 1). This association of obesity persisted after adjustment for body weight. Similar results were