Oral beta-D-glucan challenge to assess gut permeability in subjects receiving haemodialysis

Abstract Background Beta-D-glucan (BDG) levels are elevated in people receiving haemodialysis (HD), perhaps reflecting translocation of dietary BDG and gut-derived microbial products, and are a putative cause of HD-associated inflammation. BDG has been advocated as a marker of increased gut permeability. We evaluated an oral BDG challenge as a potential test for gut permeability in chronically inflamed HD patients. Methods Twenty individuals receiving either high-flux HD (HF-HD; n = 5) or haemodiafiltration (HDF; n = 15) with chronic inflammation (defined by a baseline 3-monthly median serum high sensitivity CRP ≥ 5 mg/L in the absence of a clinically detectable inflammatory condition) received a meal enriched with BDG, immediately prior to a dialysis session. Twenty people with normal kidney function (healthy comparator group) received the same meal for comparison. Serum BDG levels, measured using the Fungitell® assay, were taken at baseline, 0.5, 1, 1.5, 2, 3, 4 and 6 hours. Results Analysable data was available in 19 dialysis patients and 20 in the healthy comparator group. The dialysis group was significantly older, more comorbid and had a higher BMI. Serum BDG levels were higher in the dialysis group than in the comparator group at all timepoints. There was no significant increment post-BDG challenge in the comparator group nor in the dialysis group as a whole. However, despite similar baseline subgroup characteristics, there were disparate results in the HDF and HF-HD subgroups, with serum BDG levels rising significantly between 4 and 6 hours post challenge in the HDF group and falling slightly in the HF-HD group over the same period. Conclusions BDG levels were significantly higher the dialysis group than in the healthy comparator group but there were no significant changes in serum levels following dietary challenge in either group overall. This masked unexpected subgroup differences with serum BDG levels rising significantly post-challenge in the HDF group and falling in the HF-HD group. These subgroup findings, based on small numbers, are exploratory and underpowered, and should therefore be interpreted with caution and require confirmation in larger cohorts.