Fasciola hepatica extract suppresses fibroblast-like synoviocytes in vitro and alleviates experimental arthritis.

ABSTRACT

BACKGROUND: Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovial inflammation, fibroblast-like synoviocytes (FLS) activation and joint destruction. Fasciola hepatica is a platyhelminth that releases excretory-secretory immunomodulatory products capable of suppressing the Th1 immune response. Despite the effectiveness of available treatments for inducing disease remission, current options are not successful in all patients and may cause side effects. Thus, we evaluated the therapeutic potential of F. hepatica extract on FLS from RA patients and arthritis models. METHODS: FLS were isolated from synovial fluid of RA patients, cultured, and exposed to F. hepatica extract (60, 80, and 100 µg/ml) for different time points to assess cell viability, adherence, migration and invasion. For in vivo experiments, mice with antigen (AIA) and collagen (CIA) induced arthritis received a 200 µg/dose of F. hepatica extract daily. Statistical analysis was performed by ANOVA and Student's t-test using GraphPad Prism 6.0. RESULTS: In vitro assays showed that extract decreased FLS cell viability at concentration of 100 µg/ml (83.8% ± 5.0 extract vs. 100.0% ± 0.0 control; p < 0.05), adherence in 20% (92.0 cells ± 5.8 extract vs. 116.3 cells ± 7.9 control; p < 0.05), migratory potential (69.5% ± 17.6 extract vs. 100.0% control; p < 0.05), and cell invasiveness potential through the matrigel (76.0% ± 8.4 extract vs. 100.0% control; p < 0.01). The extract reduced leukocyte migration by 56% (40 × 104 leukocytes/knee ± 19.00) compared to control (90.90 × 104 leukocytes/knee ± 12.90) (p < 0.01) and nociception (6.37 g ± 0.99 extract vs. 3.81 g ± 1.44 control; p < 0.001) in AIA and delayed clinical onset of CIA (11.75 ± 2.96 extract vs. 14.00 ± 2.56 control; p = 0.126). CONCLUSION: Our results point out a potential immunomodulatory effect of F. hepatica extract in RA models. Therefore, the characterization of promising new immunomodulatory molecules should be pursued, as they can promote the development of new therapies. Trial registration Collection of synovial liquid and in vitro procedures were approved by the Ethics Committee with Certificate of Presentation of Ethical Appreciation in Plataforma Brasil (CAAE 89044918.8.0000.5327; date of registration 26/07/2018).