Effects of oral butyrate supplementation on inflammatory potential of circulating peripheral blood mononuclear cells in healthy and obese males.

Sodium butyrate is well-known for its immune-modulatory properties. Studies until now only focused on the in vitro effects of butyrate or assessed local effects in the gut upon butyrate administration. In this trial, we studied the systemic anti-inflammatory effects induced by sodium butyrate supplementation in humans. Nine healthy (Lean) and ten obese (metabolic syndrome group, MetSyn) males were given 4 grams sodium butyrate daily for 4 weeks. PBMCs were isolated before and after supplementation for direct stimulation experiments and induction of trained immunity by oxidized low-density lipoprotein (oxLDL), ß-glucan, or Bacillus Calmette-Guérin vaccine (BCG). Butyrate supplementation moderately affected some of the cytokine responses in the MetSyn group. In the direct stimulation setup, effects of butyrate supplementation were limited. Interestingly, butyrate supplementation decreased oxLDL-induced trained immunity in the MetSyn group for LPS-induced IL-6 responses and Pam3CSK4-induced TNF-α responses. Induction of trained immunity by ß-glucan was decreased by butyrate in the MetSyn group for Pam3CSK4-induced IL-10 production. In this study, while having only limited effects on the direct stimulation of cytokine production, butyrate supplementation significantly affected trained immunity in monocytes of obese individuals with metabolic complications. Therefore, oral butyrate supplementation may be beneficial in reducing the overall inflammatory status of circulating monocytes in patients with metabolic syndrome.

Alpha-1-anti-trypsin-Fc fusion protein ameliorates gouty arthritis by reducing release and extracellular processing of IL-1ß and by the induction of endogenous IL-1Ra.

OBJECTIVES: In the present study, we generated a new protein, recombinant human alpha-1-anti-trypsin (AAT)-IgG1 Fc fusion protein (AAT-Fc), and evaluated its properties to suppress inflammation and interleukin (IL)-1ß in a mouse model of gouty arthritis. METHODS: A combination of monosodium urate (MSU) crystals and the fatty acid C16.0 (MSU/C16.0) was injected intra-articularly into the knee to induce gouty arthritis. Joint swelling, synovial cytokine production and histopathology were determined after 4 h. AAT-Fc was evaluated for inhibition of MSU/C16.0-induced IL-1ß release from human blood monocytes and for inhibition of extracellular IL-1ß precursor processing. RESULTS: AAT-Fc markedly suppressed MSU/C16.0-induced joint inflammation by 85-91% (p<0.001). Ex vivo production of IL-1ß and IL-6 from cultured synovia were similarly reduced (63% and 65%, respectively). The efficacy of 2.0 mg/kg AAT-Fc in reducing inflammation was comparable to 80 mg/kg of plasma-derived AAT. Injection of AAT-Fc into mice increased circulating levels of endogenous IL-1 receptor antagonist by fourfold. We also observed that joint swelling was reduced by 80%, cellular infiltration by 95% and synovial production of IL-1ß by 60% in transgenic mice expressing low levels of human AAT. In vitro, AAT-Fc reduced MSU/C16.0-induced release of IL-1ß from human blood monocytes and inhibited proteinase-3-mediated extracellular processing of the IL-1ß precursor into active IL-1ß. CONCLUSIONS: A single low dose of AAT-Fc is highly effective in reducing joint inflammation in this model of acute gouty arthritis. Considering the long-term safety of plasma-derived AAT use in humans, subcutaneous AAT-Fc emerges as a promising therapy for gout attacks.