Expressions of circadian clock genes represent disease activities of RA patients treated with biological DMARDs.

Objectives: Rheumatoid Arthritis (RA) is the autoimmune disease representing the circadian variations of symptoms such as morning stiffness of joints or increased production of cytokines around midnight. Clock genes have been reported to affect on the pathogenesis of RA, however, the detailed relation between clock genes and disease activities of RA has remained unclear.Methods: In this study, 15 RA patients treated with biological disease modifying anti-rheumatic drugs (bDMARDs) were enrolled (TNF inhibitor, 5; IL-6 inhibitor, 5; CTLA4-IgG, 5). Blood samples were collected from RA patients before treatment and at the study end-point fulfilling DAS28-ESR < 3.2. Total RNA was extracted from leukocytes to examine the expressions of the clock genes. We then evaluated the correlation of the clock gene expression with disease activity and the diagnostic values of the clock genes.Results: The expressions of the clock genes were significantly modulated by bDMARDs treatments. Disease activities were significantly correlated with the clock genes expressions, and disease remission/low disease activity could be distinguished from moderate/high disease activity due to the sensitivities, the specificities and the areas under the curves of that.Conclusion: The expressions of the clock genes in leukocytes could be useful as novel biomarkers predicting disease activities and therapeutic efficacies for bDMARDs in RA treatments.

Chronotherapy targeting cytokine secretion attenuates collagen-induced arthritis in mice.

OBJECTIVE: Diurnal variation of symptoms are observed in rheumatoid arthritis, especially in productions of cytokines that show peak concentrations during mid night. In contrast, cytokines of collagen-induced arthritis (CIA) mice increase in daytimes under Mid-light condition. By using chronotherapy, differences in drug efficacies according to administration time of Baricitinib, a wide ranged cytokine blocker, were examined in CIA mice. METHODS: CIA mice were administered a dose of 3 mg/kg of Baricitinib once a day at zeitgeber time (ZT) 0 or ZT12 for 21 days. Arthritis scores, histopathology and factors related to joint destruction in sera were examined. Phosphorylation of STAT3 in liver, expressions of cytokines in spleen, and Interleukin (IL)-6 and tumor necrosis factor (TNF)-α in sera were measured. RESULTS: In CIA mice, diurnal variations were observed both in expressions of cytokines and phosphorylation of STAT3. Arthritis scores of ZT0/12 group decreased from day3 as compared to untreated mice, and those of ZT0 group significantly decreased as compared to ZT12 group from day12. Pathological findings, immunohistochemistry of cytokines and Receptor activator of nuclear factor kappa-Β ligand (RANKL)/osteoprotegerin ratio in sera well reflected results of arthritis scores. Diurnal variation of STAT3 phosphorylation was suppressed in ZT0 group. At ZT2, expressions of IL-6/Interferon-γ/TNF/granulocyte-macrophage colony-stimulating factor in ZT0 group were significantly decreased as compared to untreated mice, though not in ZT12 group. In ZT0 group, IL-6 and TNF-α in sera were decreased for longer time than that in ZT12 group. CONCLUSION: Chronotherapy using Baricitinib targeting cytokine secretions is effective in CIA mice. Clinical applications of chronotherapy can be expected to enhance the drug efficacy.

Alteration in plasma docosahexaenoic acid levels following oral administration of ethyl icosapentate to rats.

OBJECTIVES: Ethyl icosapentate, a prodrug of eicosapentaenoic acid (EPA), has been prescribed to not only hyperlipidemia, but also psychotic patients. We have examined the impact of an orally administered polyunsaturated fatty acid (PUFA), ethyl icosapentate, on the plasma concentrations of seven other types of fatty acids and one metabolite (3-hydroxybutyrate, 3-HB) using rats. DESIGN: and Methods: A commercial omega-3 PUFA, EPA, formulation (ethyl icosapentate, Epadel®) was administered orally to Sprague-Dawley rats (15, 50, 100 mg/kg, n = 4-8) and changes in the plasma fatty acid concentrations were investigated by HPLC using fluorescence detection. RESULTS: The concentration of an n-3 PUFA, docosahexaenoic acid (DHA), was significantly increased from 11.6 ±â€¯1.45 (0 h) to 25.9 ±â€¯6.54 µM (6 h) in rat plasma (n = 8, p = 1.88 × 10-2) at a dose of 100 mg/kg, as was the EPA concentration from 2.58 ±â€¯0.16 (0 h) to 6.03 ±â€¯2.20 µM (1 h) (n = 8, p = 2.09 × 10-2), whereas concentrations of other fatty acids, such as α-linolenic acid, palmitoleic acid, arachidonic acid, linolenic acid, and oleic acid, were not significantly changed. In addition, the concentration of the ultimate fatty acid metabolite, 3-hydroxybutyrate (3-HB), was significantly increased (from 94.6 ±â€¯10.2 to 217 ±â€¯43.4, p = 5.41 × 10-3) 12 h after oral administration of ethyl icosapentate (n = 8, 100 mg/kg). CONCLUSIONS: This result suggests that intake of the EPA formulation contributed not only to an increase in EPA concentration, but also to increases in DHA and 3-HB concentrations in vivo.