Maren Dreiner (Cologne), Elie-Tino Godonou (Erlangen), PD Dr. Anna-Maria Liphardt (Erlangen), Prof. Dr. Anja Niehoff (Cologne)
Abstract-Text (inkl. Referenzen und Bildunterschriften)
Introduction: In healthy male participants, bed rest immobilization leads to alterations in serum cartilage biomarker concentrations [1], while in females this effect has not been investigated to date. Cartilage oligomeric matrix protein (COMP) is a mechanosensitive biomarker of cartilage degeneration [2]. Dry immersion (DI) is an immobilization model that simulates a support-free environment and restricts movement. We aimed to examine serum COMP (sCOMP) concentrations in females compared to males during 5 days of DI immobilization.
Methods: This study was conducted at the Institute de Médecine et de Physiologie Spatiales (MEDES), Toulouse, France. 18 healthy females (29±5 years, 165±6 cm, 59±6 kg) and 19 males (28±4 years, 177±4 cm, 72±7 kg) underwent 4 days of baseline data collection (BDC), 5 days of DI (24 hrs/day), and 3 days of recovery (R) (Figure 1). Fasting venous blood samples were collected on BDC-50h, BDC-26h, DI46h, DI118h and R+46h. sCOMP concentrations were analyzed by commercially available ELISA (BioVendor R&D®). Repeated measures ANOVA (LSD post-hoc test) with sex as between-subjects factor was performed.
Results: sCOMP levels did not differ between females and males (p=0.831, Table 1). Consequently, they were pooled for further analysis. DI led to a substantial decrease in sCOMP levels (p<0.001) and a subsequent increase (p<0.001) to BDC levels during remobilization.
Conclusion: sCOMP concentrations were clearly reduced after 46hrs of DI, with no sex differences, indicating perturbed cartilage metabolism. The observed reduction in sCOMP was more pronounced during DI (-35%) compared to the effect measured in a previous 5 days bed rest study (-23%) [1].
[1] Liphardt AM et al., J Orthop Res. 38:2373-2382, 2020
[2] Tseng S et al., Biomark Insights. 4:33-44, 2009
Acknowledgements: European Space Agency, Federal Ministry of Economic Affairs and Energy, Germany (DLR 50WB2021, DLR 50WB2022), participating volunteers, MEDES study team, Toulouse, France.