{
  "abstract": "Introduction Intestinal barrier dysfunction, as measured by increased permeability, is a key feature of several gastrointestinal diseases, but current assessments rely on urinary sugar excretion tests that are impractical for routine use. Transcutaneous fluorescence spectroscopy (TFS) is a novel, non-invasive method for assessing small bowel permeability by detecting fingertip fluorescence with a pulse oximeter–like sensor following oral sodium fluorescein ingestion.Methods To validate TFS, 15 healthy volunteers (M:F=9:6) underwent permeability assessment across 4 days in a prospective study. Oral indomethacin was used to induce increased small bowel permeability. Baseline TFS and 0-2 hr %urinary lactulose excretion were measured on Day 1, followed by repeat assessment after oral indomethacin on Day 2. After > 2 weeks washout, the protocol was repeated on Day 3 (baseline) and 4 (post-indomethacin). TFS permeability was quantified as area under the fluorescence–time curve (AUC). Linear mixed-effects models (LMMs) assessed indomethacin effects and associations between AUC and %lactulose excretion, accounting for repeated measures. Individual-level responses were analysed as post–pre indomethacin differences (Days 2+4 - Days 1+3) using Pearson and Spearman correlations.Results Indomethacin induced a noticeable increase in the mean TFS fluorescence intensity relative to baseline ( figure 1A). AUC increased after indomethacin in 19/29 (66%) paired measurements (figure 1B). LMM analysis showed a significant indomethacin-associated increase in AUC (β = 2.61, 95% CI 0.52–4.70; p = 0.015, figure 1C), with no evidence of an independent period effect (β = 0.60, 95% CI −1.52–2.72; p = 0.58). AUC was also positively associated with %lactulose excretion (β = 15.9 per %lactulose, 95% CI 0.9–31.0; p = 0.038; figure 1D). Individual-level changes in AUC were not correlated with changes in % lactulose excretion. (Pearson r = −0.05, p = 0.86; Spearman ρ = −0.25, p = 0.37).Conclusions TFS detects indomethacin-induced increases in small bowel permeability and shows a consistent association with urinary lactulose excretion across repeated measures. Lack of individual-level corelation may reflect detection of complementary aspects of barrier function by different methods. TFS is a sensitive, non-invasive approach. This study strongly supports further evaluation in patient populations.Abstract P387 Figure 1TFS small bowel permeability. (A) Combined fluorescence vs time curve at baseline (Day 1&3) and after indomethacin (Day 2&4). Shaded area indicates IQR. (B) Individual AUC changes pre- and post-indomethacin. Bold line indicates mean change. (C) AUC at baseline and after indomethacin days. (D) Spaghetti plot of AUC vs %lactulose excretion. Connected points indicate within-individual change; trend line shown for illustration. (LMM: p=0.039, β =15.9)",
  "authors": [
    {
      "affiliations": [
        "Imperial College London, London, United Kingdom",
        "Imperial College Healthcare NHS Trust, London, United Kingdom"
      ],
      "name": "Qian Chen"
    },
    {
      "affiliations": [
        "Imperial College London, London, United Kingdom"
      ],
      "name": "Nilanjan Mandal"
    },
    {
      "affiliations": [
        "Imperial College London, London, United Kingdom"
      ],
      "name": "Pratik Ramkumar"
    },
    {
      "affiliations": [
        "Nxera Pharma, Cambridge, United Kingdom"
      ],
      "name": "Joey Leung"
    },
    {
      "affiliations": [
        "Nxera Pharma, Cambridge, United Kingdom"
      ],
      "name": "Graeme Scarfe"
    },
    {
      "affiliations": [
        "Nxera Pharma, Cambridge, United Kingdom"
      ],
      "name": "Marsilio Adriani"
    },
    {
      "affiliations": [
        "Nxera Pharma, Cambridge, United Kingdom"
      ],
      "name": "Rie Suzuki"
    },
    {
      "affiliations": [
        "Imperial College London, London, United Kingdom"
      ],
      "name": "Alex Thompson"
    }
  ],
  "title": "P387 Non-invasive measure of small bowel barrier function with transcutaneous fluorescence spectroscopy: validation in healthy volunteers",
  "uid": "0b06e6d1-bcc0-5089-af3a-2bd16a0e4675"
}