Free lipoproteins from Bifidobacterium longum alleviate osteoarthritis through modulation of the gut microbiome

Hand Osteoarthritis: Molecular Mechanisms, Randomized Controlled Trials, and the Future of Targeted Treatment

Hand osteoarthritis (OA) is a prevalent and disabling condition, yet its pathogenesis remains less studied than OA in large weight-bearing joints. Emerging genetic, epigenetic, and microbiome research suggests that hand OA might be biologically distinct, involving joint-specific pathways not shared by knee or hip OA. This review integrates genome-wide association studies specific to hand OA, highlighting key molecular contributors such as inflammatory cytokines. These genetic insights, together with emerging data on epigenetic alterations and gut microbial dysbiosis, point to broader systemic and regulatory influences on hand OA onset and progression. We also assess pharmacologic interventions tested in randomized controlled trials that have attempted to target these pathways. While agents such as TNF and IL-6 inhibitors, hydroxychloroquine, and corticosteroids have shown limited success, emerging evidence supports the potential of methotrexate in synovitis-positive general hand OA, platelet-rich plasma in thumb carpometacarpal (CMC) OA, and prolotherapy in interphalangeal (IP) OA. These findings illustrate the persistent gap between mechanistic understanding and therapeutic success. Future work must prioritize multifactorial strategies for addressing pain and translational frameworks that link molecular mechanisms to treatment response. In summary, this review offers an update on hand OA and identifies key opportunities for more targeted and effective therapy.

Gut and Joint Microbiomes: Implications in Osteoarthritis

This review summarizes and discusses key recent findings suggesting that microbiomes can play a role in the development and progression of osteoarthritis. Evidence supporting a gut microbiome-joint connection derived from human and animal studies is enumerated and discussed, with particular attention on the microbial and molecular basis for the development of therapeutic interventions that involve targeting the gut. Additionally, clinical data supporting the concept of a living microbiome within a diarthrodial joint are summarized. A discussion of key limitations in the current data and important technical considerations for firmly establishing the existence of a synovial joint microbial community is included.

Human milk oligosaccharides 2'-fucosyllactose and 3-fucosyllactose attenuate ovalbumin-induced food allergy through immunoregulation and gut microbiota modulation

The prebiotic properties of human milk oligosaccharides (HMOs) and emerging evidence of immunomodulatory effects suggest their potential therapeutic value in allergy management. 2'-Fucosyllactose (2'-FL) has been reported to alleviate food allergies, while the effect of other fucosylated HMOs on food allergy remains unclear. In this study, we assess the effect of two HMOs, 2'-FL and 3-fucosyllactose (3-FL), on symptomatology and immunological responses in an ovalbumin (OVA)-sensitized mouse model of food allergy as well as their influence on gut microbiota. The assessment of allergic symptoms, specific immunoglobulin E (IgE), and related gene expression levels in sensitized mice indicated that 3-FL was as effective as 2'-FL in alleviating food allergy. 2'-FL and 3-FL significantly decreased serum levels of OVA-specific IgE, mouse mast cell protease (mMCP-1) and IL-4 while increasing the levels of IFN-γ. Additionally, 2'-FL and 3-FL down-regulated gene expression of allergy-related cytokines in the small intestine and improved intestinal barrier damage. Furthermore, both 2'-FL and 3-FL treatment positively influenced the gut microbial profiles, in particular by enhancing the proportion of beneficial bacteria such as Lactobacillus and Bifidobacterium and decreasing the percentage of Turicibacter and Lachnospiraceae NK4A136 group, thereby modulating the immune system. Therefore, this study can provide insights into 2'-FL and 3-FL to alleviate OVA-induced allergy.

Gut-Joint Axis: Impact of Bifidobacterial Cell Wall Lipoproteins on Arthritis Development

Gut microbiota affect progression of rheumatoid arthritis (RA). The present study aims at investigating the protective potential of Bifidobacterium longum cell wall lipoproteins (Lpps) shown to modulate the intestinal microbiome and prevent osteoarthritis. Arthritis was induced by collagen (CIA) or anti-collagen antibodies (CAIA) injection. Intake of 0.5 mg of Lpps/L, but not 0.25 and 1 mg of Lpps/L, significantly alleviated RA symptoms in CIA DBA/1OOaHsd mice. The arthritis index (AI) was also reduced in CAIA mice. In the CIA-protected group, colon Ligilactobacillus murinus, caecal Lactobacillus johnsonii and spleen weight correlated with AI, whereas the reverse was observed with splenic CD11c+ dendritic cells (cDCs). The unprotected CIA Lpps group harbored higher cecal and colon E. coli and lower caecal L. murinus. Lpps administration to CAIA mice after arthritis induction led to lower colon E. plexicaudatum counts. Splenocytes from CIA-protected mice triggered by LPS secreted higher Il-10 than control ones. However, a higher IL-10 response was not elicited in gnotobiotic RA mice splenocytes with lower cDCs' recruitment. Labeled bacteria with the Lpps signal were detected in CIA mice bone marrow (BM) cDCs 5 and 16 h post-gavage but not in Peyer's patches and the spleen. In vitro uptake of Lpps by primary BM and thymus cells was observed within 24 h. An FACS analysis detected the Lpps signal in the plasmacytoid cell compartment but not in cDCs. In conclusion, Lpps dosing is critical for preventing arthritis progression and appropriately modulating the microbiome. Our results also highlight the possible triggering of the immune system by Lpps.