POS0371 BIOLOGICAL REPRODUCIBILITY OF TARGETED LIPIDOME ANALYSES IN PLASMA AND ERYTHROCYTES OVER A 6-WEEK PERIOD

Background: Lipidomics analysis has become a valuable technology for understanding patho-physiological mechanisms and the identification of candidate biomarkers in rheumatic musculoskeletal disorders. Variability within-subject repeated measurements may lead to bias towards null when estimating association between disease or treatment. Hence, information regarding stability metabolite levels over time is essential. Objectives: We aimed assess lipid composition biological reproducibility plasma erythrocytes. Methods: Plasma erythrocyte samples from 42 osteoarthritis patients (77% women, mean age 65 years, BMI 27 kg/m2), obtained non-fasted at baseline six weeks, were used quantitative measurement up 1000 species across 13 classes with LipidyzerTM platform nmol/mL. Data was processed based on relative standard deviation quality controls, taking batch effects into account. Intraclass correlation coefficients (ICCs) corresponding 95% confidence intervals (CI) calculated investigate variability concentrations timepoints. The ICC distribution metabolites erythrocytes compared using two-sided paired Wilcoxon tests. Results: measured 778 lipids plasma, 916 After data processing, analyses included 630 286 From these, 243 overlapped sample types. Major differences observed types number per class total concentration within class. Triacylglycerols (TAG) cholesteryl esters (CE) more abundant plasma. Conversely, phosphatidylethanolamines (PE), sphingomyelins (SM) ceramides (CER) less (table 1). In 78% good excellently reproduced, an overall median 0.69. Compared considerably lower amount (35%) well reproduced Median 0.51. Figure 1 shows score erythrocytes, significantly better (p-value<0.001). However, while this not all classes. At class-level, superior TAGs CEs, CERs, DAGs, (L)PEs SMs showed Table 1. Number individual Erythrocytes Class (nmol/mL) 482 1579.4 (1064.9-3195.2) 134 6.5 (5.6-9.4) Diacylglycerols 9 13.3 (8.4-22.2) 10 5.8 (4.7-6.2) Free fatty acids 20 745.3 (552.0-1202.9) 486.9 (379.2-669.2) Cholesteryl 24 4571.6 (4065.1-5521.3) 5 1.2 (0.9-1.7) Phosphatidylcholines 31 4013.7 (3203.1-4661.6) 3899.2 (3723.0-4296.6) Phosphatidylethanolamines 26 156.2 (120.9-180.3) 3954.6 (3721.9-4323.3) Lysophosphatidylcholines 385.9 (335.6-442.9) 7 119.8 (109.7-168.9) Lysophosphatidylethanolamines 2 4.2 (3.5-4.9) 4 8.6 (6.8-9.7) Sphingomyelins 12 1204.6 (1037.0-1351.9) 8 2695.8 (2434.8-2815.6) Ceramides 6 14.1 (11.9-17.4) 163.0 (133.3-186.4) Dihydroceramides 1.0 (0.8-1.3) 1.8 (1.4-2.1) Hexosylceramides 5.1 (4.7-5.9) 5.6 (5.0-7.4) Lactosylceramides 3.4 (2.7-3.8) 23.8 (20.6-33.5) Numbers represent (interquartile range) unless otherwise specified. represents measurements. Conclusion: most Although notable individual- class-level that favour use particular type. Disclosure Interests: Marieke Loef: None declared, Johannes von Hegedus: Mohan Ghorasaini: Féline Kroon: Martin Giera Shareholder of: Pfizer, Consultant Boehringer Ingelheim Pharma, Andreea Ioan-Facsinay: Margreet Kloppenburg: declared