Plain language summary
Psoriatic arthritis is a chronic inflammatory condition that causes joint pain and swelling along with red, flaky, and scaly skin. Inflammation affects the extracellular matrix, which comprises proteins and molecules that support cartilage, bone, and soft tissues in joints. A high level of collagen fragments is released into the bloodstream as a result. Fish oils and fish are good sources of n-3 polyunsaturated fatty acids (n-3 PUFA), including eicosapentaenoic acid and docosahexaenoic acid. Inflammation and joint pain have been shown to be reduced by n-3 PUFA in previous studies. This randomised, double-blinded, placebo-controlled study randomly assigned 142 patients with psoriatic arthritis to receive 3g n-3 PUFA (50% EPA and 50% DHA) or 3g of olive oil as the control for 24 weeks. Taking N-3 PUFA supplementation did not affect extracellular matrix turnover in psoriatic arthritis patients. This may be due to the anti-inflammatory properties of olive oil, which was used as a control, and to the short duration of the study. The benefits of using n-3 PUFA as a therapeutic strategy in patients with psoriatic arthritis need to be evaluated in larger, robust long-term studies. Furthermore, the clinical efficacy of n-3 PUFA cannot be distinguished since 75% of the patients took anti-rheumatic drugs. A study like this can provide healthcare professionals with insights into the potential benefits of n-3 PUFAs, which may aid them in making therapeutic decisions.
Abstract
Psoriatic arthritis (PsA) is a chronic inflammatory disease characterized by involvement of skin, axial and peripheral skeleton. An altered balance between extracellular matrix (ECM) formation and breakdown is a key event in PsA, and changes in ECM protein metabolites may provide insight to tissue changes. Dietary fish oils (n-3 PUFA) might affect the inflammation driven tissue turnover. The aim was to evaluate ECM metabolites in patients with PsA compared to healthy individuals and investigate the effects of n-3 PUFA. The 24-week randomized, double-blind, placebo-controlled trial of PUFA included 142 patients with PsA. Fifty-seven healthy individuals were included for comparison. This study is a sub-study investigating biomarkers of tissue remodelling as secondary outcomes. Serum samples at baseline and 24 weeks and healthy individuals were obtained, while a panel of ECM metabolites reflecting bone and soft tissue turnover were measured by ELISAs: PRO-C1, PRO-C3, PRO-C4, C1M, C3M, C4M, CTX-I and Osteocalcin (OC). C1M, PRO-C3, PRO-C4 and C4M was found to be elevated in PsA patients compared to the healthy individuals (from 56 to 792%, all p < 0.0001), where no differences were found for OC, CTX-I, PRO-C1 and C3M. PRO-C3 was increased by 7% in patients receiving n-3 PUFA after 24 weeks compared to baseline levels (p = 0.002). None of the other biomarkers was changed with n-3 PUFA treatment. This indicates that tissue turnover is increased in PsA patients compared to healthy individuals, while n-3 PUFA treatment for 24 weeks did not have an effect on tissue turnover. Trial registration NCT01818804. Registered 27 March 2013-Completed 18 February 2016. https://clinicaltrials.gov/ct2/show/NCT01818804?term=NCT01818804&rank=1.
Methodological quality
Jadad score
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4
Allocation concealment
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No
