Euglena gracilis Z and its carbohydrate storage substance relieve arthritis symptoms by modulating Th17 immunity

Abstract

Euglena gracilis Z is a microorganism classified as a microalga and is used as a food or nutritional supplement. Paramylon, the carbohydrate storage substance of E. gracilis Z, is reported to affect the immunological system. This study evaluated the symptom-relieving effects of E. gracilis Z and paramylon in rheumatoid arthritis in a collagen-induced arthritis mouse model. The efficacy of both substances was assessed based on clinical arthritis signs, as well as cytokine (interleukin [IL]-17, IL-6, and interferon [IFN]-γ) levels in lymphoid tissues. Additionally, the knee joints were harvested and histopathologically examined. The results showed that both substances reduced the transitional changes in the visual assessment score of arthritis symptoms compared with those in the control group, indicating their symptom-relieving effects on rheumatoid arthritis. Furthermore, E. gracilis Z and paramylon significantly reduced the secretion of the cytokines, IL-17, IL-6, and IFN-γ. The histopathological examination of the control group revealed edema, inflammation, cell hyperplasia, granulation tissue formation, fibrosis, and exudate in the synovial membrane, as well as pannus formation and articular cartilage destruction in the femoral trochlear groove. These changes were suppressed in both treatment groups. Particularly, the E. gracilis Z group showed no edema, inflammation, and fibrosis of the synovial membrane, or pannus formation and destruction of articular cartilage in the femoral trochlear groove. Furthermore, E. gracilis Z and paramylon exhibited symptom-relieving effects on rheumatoid arthritis and suppressed the secretion of cytokines IL-17, IL-6, and IFN-γ. These effects were likely mediated by the regulatory activities of E. gracilis Z and paramylon on Th17 immunity. In addition, the symptom-relieving effects of both substances were comparable, which suggests that paramylon is the active component of Euglena gracilis Z.

Accelerated Wound Healing on the Skin Using a Film Dressing with β-Glucan Paramylon

“…In a previous study, oral administration of paramylon significantly reduces the secretion of the cytokines IL-17, IL-6, and IFN-γ in lymphoid tissues, resulting in suppression of the onset of arthritis in rodent models (37). Paramylon improved the symptoms of atopic dermatitis and decreased the secretion of IL-4, IFN-γ, IL-18, and IL-12 in NC/Nga mice (23).…”

Euglena Gracilis and β-Glucan Paramylon Induce Ca2+ Signaling in Intestinal Tract Epithelial, Immune, and Neural Cells

“…In addition, the subcutaneous application of β-1,3-glucan extracted from Saccharomyces cerevisiae in 20 children with asthma increased serum levels of the anti-inflammatory cytokine IL-10 and simultaneously reduced symptom scores [10]. The oral intake of paramylon has been found to reduce cytokine secretion and relieve arthritis symptoms in mice by modulating Th17 immunity [44], while studies have suggested that Euglena and paramylon could reduce upper respiratory tract infection symptoms and protect against influenza virus infection [13,45]. Here, we found that IP Euglena and paramylon injection stimulated DCs in PPs in vivo, with stronger Ca 2+ signaling observed with paramylon treatment; thus, paramylon may be the active component of Euglena that affects the immunological system.…”

Effects of Euglena gracilis Intake on Mood and Autonomic Activity under Mental Workload, and Subjective Sleep Quality: A Randomized, Double-Blind, Placebo-Controlled Trial

“…The storage polysaccharide paramylon in Euglena regulates the immune balance. Previous studies of mouse models have confirmed that the ingestion of Euglena or paramylon alleviates the symptoms of influenza infection [ 11 ], rheumatoid arthritis [ 43 ], and atopic dermatitis [ 44 ]. The autonomic nervous system is involved in the regulation of immunity, and immunity is generally enhanced in situations where the parasympathetic nervous system is dominant, contributing to defense against infection [ 16 , 17 ].…”