TY - JOUR
T1 - Hyperbaric oxygen therapy alters bowel perfusion and improves outcomes in patients with treatment-refractory ulcerative colitis
T2 - a prospective pilot trial
AU - Mulders, Lieven
AU - Pruijt, Maarten
AU - van Oostrom, Joep
AU - van der Zanden, Esmerij
AU - Neefjes-Borst, Andra
AU - Koelink, Pim
AU - Wildenberg, Manon
AU - de Jonge, Wouter
AU - Ridderikhof, Milan
AU - van Hulst, Rob
AU - D’Haens, Geert
AU - Gecse, Krisztina
N1 - Publisher Copyright:
© The Author(s) 2026. Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
PY - 2026/5/1
Y1 - 2026/5/1
N2 - Background: Hyperbaric oxygen therapy (HBOT) delivers 100% oxygen in a pressurized chamber and enhances tissue oxygenation and neovascularization. While effective in radiation proctitis, acute severe ulcerative colitis, and perianal fistulizing Crohn’s disease, its role in refractory ulcerative colitis (UC) remains underexplored. Methods: PARADOX was a prospective, open-label, phase 2a pilot trial in biologic-experienced patients with moderate-to-severe refractory UC (total Mayo > 5, Mayo endoscopic subscore (MES) ≥ 2, failure of ≥ 2 advanced therapies). Patients received 10 or 20 daily HBOT sessions (2.4 atmospheres absolute, 120 minutes/day) while continuing stable background therapy. The primary endpoint was composite clinical and endoscopic response at week 12 (≥ 3-point and 30% Mayo score reduction, rectal bleeding score = 0, and ≥ 1-point decrease in MES). Secondary outcomes included symptomatic, biochemical, and transmural response by intestinal ultrasound (IUS), including perfusion metrics via contrast-enhanced ultrasound (CEUS). Results: In total, 16 patients (8 per group) were included in this pilot study. At week 12, composite response was achieved in 2/8 (10-session) and 4/8 (20-session) patients. Improvements in clinical, endoscopic, and IUS parameters were observed in both groups. Clinical responders showed increased CEUS perfusion at week 12 (peak enhancement Δ12.1 dB), while non-responders declined (Δ –5.4 dB). This pattern was consistent across wash-in/wash-out metrics, supporting a volume perfusion-based response. HBOT was well tolerated, with no serious adverse events or treatment discontinuations. Conclusion: HBOT is a well-tolerated adjunctive therapy in refractory UC, which improved clinical outcomes and perfusion kinetics. These findings support further evaluation in a randomized, dose-optimized trial. Euclinicaltrials.eu,
AB - Background: Hyperbaric oxygen therapy (HBOT) delivers 100% oxygen in a pressurized chamber and enhances tissue oxygenation and neovascularization. While effective in radiation proctitis, acute severe ulcerative colitis, and perianal fistulizing Crohn’s disease, its role in refractory ulcerative colitis (UC) remains underexplored. Methods: PARADOX was a prospective, open-label, phase 2a pilot trial in biologic-experienced patients with moderate-to-severe refractory UC (total Mayo > 5, Mayo endoscopic subscore (MES) ≥ 2, failure of ≥ 2 advanced therapies). Patients received 10 or 20 daily HBOT sessions (2.4 atmospheres absolute, 120 minutes/day) while continuing stable background therapy. The primary endpoint was composite clinical and endoscopic response at week 12 (≥ 3-point and 30% Mayo score reduction, rectal bleeding score = 0, and ≥ 1-point decrease in MES). Secondary outcomes included symptomatic, biochemical, and transmural response by intestinal ultrasound (IUS), including perfusion metrics via contrast-enhanced ultrasound (CEUS). Results: In total, 16 patients (8 per group) were included in this pilot study. At week 12, composite response was achieved in 2/8 (10-session) and 4/8 (20-session) patients. Improvements in clinical, endoscopic, and IUS parameters were observed in both groups. Clinical responders showed increased CEUS perfusion at week 12 (peak enhancement Δ12.1 dB), while non-responders declined (Δ –5.4 dB). This pattern was consistent across wash-in/wash-out metrics, supporting a volume perfusion-based response. HBOT was well tolerated, with no serious adverse events or treatment discontinuations. Conclusion: HBOT is a well-tolerated adjunctive therapy in refractory UC, which improved clinical outcomes and perfusion kinetics. These findings support further evaluation in a randomized, dose-optimized trial. Euclinicaltrials.eu,
KW - hyperbaric oxygen therapy
KW - neovascularization
KW - ulcerative colitis
UR - https://www.scopus.com/pages/publications/105039045067
U2 - 10.1093/ecco-jcc/jjag065
DO - 10.1093/ecco-jcc/jjag065
M3 - Article
C2 - 42136082
SN - 1873-9946
VL - 20
JO - J. Crohn's Colitis
JF - J. Crohn's Colitis
IS - 5
M1 - jjag065
ER -