Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 May 4;10(5):401.
doi: 10.3390/biology10050401.

Synovial Fluid Fatty Acid Profiles Are Differently Altered by Inflammatory Joint Pathologies in the Shoulder and Knee Joints

Anne-Mari Mustonen  1   2 , Reijo Käkelä  3   4 , Antti Joukainen  5 , Petri Lehenkari  6   7 , Antti Jaroma  8 , Tommi Kääriäinen  5 , Heikki Kröger  8 , Tommi Paakkonen  1 , Sanna P Sihvo  3   4 , Petteri Nieminen  1
Affiliations

Synovial Fluid Fatty Acid Profiles Are Differently Altered by Inflammatory Joint Pathologies in the Shoulder and Knee Joints

Anne-Mari Mustonen et al. Biology (Basel). .

Abstract

Anomalies of fatty acid (FA) metabolism characterize osteoarthritis (OA) and rheumatoid arthritis (RA) in the knee joint. No previous study has investigated the synovial fluid (SF) FA manifestations in these aging-related inflammatory diseases in the shoulder. The present experiment compared the FA alterations between the shoulder and knee joints in patients with end-stage OA or end-stage RA. SF samples were collected during glenohumeral or knee joint surgery from trauma controls and from OA and RA patients (n = 42). The FA composition of SF total lipids was analyzed by gas chromatography with flame ionization and mass spectrometric detection and compared across cohorts. The FA signatures of trauma controls were mostly uniform in both anatomical locations. RA shoulders were characterized by elevated percentages of 20:4n-6 and 22:6n-3 and with reduced proportions of 18:1n-9. The FA profiles of OA and RA knees were relatively uniform and displayed lower proportions of 18:2n-6, 22:6n-3 and total n-6 polyunsaturated FAs (PUFAs). The results indicate location- and disease-dependent differences in the SF FA composition. These alterations in FA profiles and their potential implications for the production of PUFA-derived lipid mediators may affect joint lubrication, synovial inflammation and pannus formation as well as cartilage and bone degradation and contribute to the pathogeneses of inflammatory joint diseases.

Keywords: fatty acid; knee; n-3 polyunsaturated fatty acids; n-6 polyunsaturated fatty acids; osteoarthritis; rheumatoid arthritis; shoulder; synovial fluid.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
The percentages (mol-%; individual values and means) of selected saturated fatty acids in the synovial fluid samples. C = control, OA = osteoarthritis, RA = rheumatoid arthritis. * = significant difference between the two study groups at the ends of the connecting line (p < 0.05).
Figure 2
Figure 2
The percentages (mol-%; individual values and means) of selected monounsaturated fatty acids (MUFA) and their sum in the synovial fluid samples. C = control, OA = osteoarthritis, RA = rheumatoid arthritis. * = significant difference between the two study groups at the ends of the connecting line (p < 0.05).
Figure 3
Figure 3
The percentages (mol-%; individual values and means) of selected polyunsaturated fatty acids (PUFA) and their sums in the synovial fluid samples. C = control, OA = osteoarthritis, RA = rheumatoid arthritis. * = significant difference between the two study groups at the ends of the connecting line (p < 0.05).
Figure 4
Figure 4
Discriminant analyses depicting the classification of fatty acid signatures in synovial fluids. (A) OA knee samples were only included from the Kuopio subgroup, (B) OA knee subgroups were from both Kuopio and Oulu. OA = osteoarthritis, RA = rheumatoid arthritis. Note that the scaling is different in the x- and y-axes and between the panels.
See this image and copyright information in PMC

References

    1. Frommer K.W., Schäffler A., Rehart S., Lehr A., Müller-Ladner U., Neumann E. Free fatty acids: Potential proinflammatory mediators in rheumatic diseases. Ann. Rheum. Dis. 2015;74:303–310. doi: 10.1136/annrheumdis-2013-203755. - DOI - PubMed
    1. Frommer K.W., Hasseli R., Schäffler A., Lange U., Rehart S., Steinmeyer J., Rickert M., Sarter K., Zaiss M.M., Culmsee C., et al. Free fatty acids in bone pathophysiology of rheumatic diseases. Front. Immunol. 2019;10:2757. doi: 10.3389/fimmu.2019.02757. - DOI - PMC - PubMed
    1. Jónasdóttir H.S., Brouwers H., Kwekkeboom J.C., van der Linden H.M.J., Huizinga T., Kloppenburg M., Toes R.E.M., Giera M., Ioan-Facsinay A. Targeted lipidomics reveals activation of resolution pathways in knee osteoarthritis in humans. Osteoarthr. Cartil. 2017;25:1150–1160. doi: 10.1016/j.joca.2017.01.018. - DOI - PubMed
    1. Guilak F. Biomechanical factors in osteoarthritis. Best Pract. Res. Clin. Rheumatol. 2011;25:815–823. doi: 10.1016/j.berh.2011.11.013. - DOI - PMC - PubMed
    1. Boden G. Obesity and free fatty acids. Endocrinol. Metab. Clin. N. Am. 2008;37:635–646. doi: 10.1016/j.ecl.2008.06.007. - DOI - PMC - PubMed

Grants and funding