A double-blind, randomized, placebo-controlled study to explore the efficacy of a dietary plant-derived polysaccharide supplement in patients with rheumatoid arthritis.

OBJECTIVES: There is increased interest in the potential benefits of complementary therapies, of which dietary plant-derived polysaccharides (dPPs) are an important component. We examined the impact of oral ingestion of a pre-biotic dPP supplement active compound (AC) on serum glycosylation and clinical variables associated with inflammation and general health in patients with RA. METHODS: A double-blind, placebo-controlled, parallel-group clinical trial was used. Participants were randomly assigned to receive AC (n = 33) or placebo (n = 36) for 6 months. Serum protein N-glycosylation was determined by mass spectrometry. Patient outcomes were assessed by validated clinical trial health questionnaires. The primary clinical efficacy variable was DAS-28. RESULTS: The groups had comparable baseline clinical characteristics. AC was well tolerated with low drop-out rates. Supplementation resulted in a 12% significant drop in the levels of the agalactosylated (G0F) glycans [8.10 (0.89) to 7.16 (0.60); P = 0.03], but had no significant overall effect on patient outcomes. The placebo-treated group showed no change in G0F but exhibited a reduction in the levels of fully digalactosylated (G2) glycans (11%; P = 0.03). Although not clinically significant, DAS scores were, however, marginally lower in the placebo group [difference = 0.63 (0.23) s.e.; 95% CI 0.17, 1.10; P = 0.009], as were two of the secondary variables. CONCLUSIONS: Short-term dietary supplementation with AC resulted in a moderate, but significant, reduction in G0F levels, but did not result in any clinically significant improvement in disease activity when assessing the study group as a whole.

Glucose homeostasis across human airway epithelial cell monolayers: role of diffusion, transport and metabolism.

Glucose in airway surface liquid (ASL) is maintained at low concentrations compared to blood glucose. Using radiolabelled [(3)H]-D: -glucose and [(14)C]-L: -glucose, detection of D: - and L: -glucose by high-performance liquid chromatography and metabolites by nuclear magnetic resonance, we found that glucose applied to the basolateral side of H441 human airway epithelial cell monolayers at a physiological concentration (5 mM) crossed to the apical side by paracellular diffusion. Transepithelial resistance of the monolayer was inversely correlated with paracellular diffusion. Appearance of glucose in the apical compartment was reduced by uptake of glucose into the cell by basolateral and apical phloretin-sensitive GLUT transporters. Glucose taken up into the cell was metabolised to lactate which was then released, at least in part, across the apical membrane. We suggest that glucose transport through GLUT transporters and its subsequent metabolism in lung epithelial cells help to maintain low glucose concentrations in human ASL which is important for protecting the lung against infection.

Identification of a second lipopolysaccharide in Porphyromonas gingivalis W50.

We previously described a cell surface anionic polysaccharide (APS) in Porphyromonas gingivalis that is required for cell integrity and serum resistance. APS is a phosphorylated branched mannan that shares a common epitope with posttranslational additions to some of the Arg-gingipains. This study aimed to determine the mechanism of anchoring of APS to the surface of P. gingivalis. APS was purified on concanavalin A affinity columns to minimize the loss of the anchoring system that occurred during chemical extraction. (1)H nuclear magnetic resonance spectroscopy of the lectin-purified APS confirmed the previous structure but also revealed additional signals that suggested the presence of a lipid A. This was confirmed by fatty acid analysis of the APS and matrix-assisted laser desorption ionization-time of flight mass spectrometry of the lipid A released by treatment with sodium acetate buffer (pH 4.5). Hence, P. gingivalis synthesizes two distinct lipopolysaccharide (LPS) macromolecules containing different glycan repeating units: O-LPS (with O-antigen tetrasaccharide repeating units) and A-LPS (with APS repeating units). Nonphosphorylated penta-acylated and nonphosphorylated tetra-acylated species were detected in lipid A from P. gingivalis total LPS and in lipid A from A-LPS. These lipid A species were unique to lipid A derived from A-LPS. Biological assays demonstrated a reduced proinflammatory activity of A-LPS compared to that of total LPS. Inactivation of a putative O-antigen ligase (waaL) at PG1051, which is required for the final step of LPS biosynthesis, abolished the linkage of both the O antigen and APS to the lipid A core of O-LPS and A-LPS, respectively, suggesting that WaaL in P. gingivalis has dual specificity for both O-antigen and APS repeating units.