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* = Presenting author

P044. Novel image using hydrogen sulfide multiphoton probe in the mucosal tissue of ulcerative colitis patients

E.S. Kim1, Y.T. Jeen1, B. Keum1, H.J. Chun1, B.J. Lee1, J.S. Koo1, R.S. Choung1, J.H. Choi1, B.R. Cho2, 1Korea University College of Medicine, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Seoul, South Korea, 2Korea University, Department of Chemistry, Seoul, South Korea

Background

Hydrogen sulfide (H2S) exerts many effects in the digestive system, including anti-inflammatory actions (inhibition of leukocyte-endothelial adherence, reduced edema formation) and suppression of oxidative stress. H2S can be produced through the enzymatic degradation of L-cystein. There have been debates on the significant physiologic roll of H2S in the ulcerative colitis patients. Some studies reported luminal H2S is not elevated in UC patients, others reported H2S is a bacterial toxin in UC. To understand its role, it is crucial to monitor the H2S level in the living tissue. For this purpose, we use novel H2S multiphoton probe (FS1) to obtain the image of H2S in colitis mucosa.

Methods

Multiphoton probe for H2S (FS1) are synthesized by alkylation of 2-bromofluorene with 2-(2-methoxy­ethoxy)­ethyl tosylate followed by the coupling with benzothiazole and regioselective nitration. Subsequent reduction of the nitro group by Fe/NH4Cl, and FS1 was obtained by diazotization-azidation. Colonic mucosal tissues were obtained from ulcerative colitis patients who had left side UC during colonoscopic biopsy. Inflammation tissues were from active UC mucosa and control tissues were from grossly normal colonic mucosa of right side colon.

Results

FS1 showed good selectivity for H2S over other biologically relevant reactive sulfur (RSS), oxygen (ROS) and nitrogen species (RNS). 20 µM of FS1 was used to staining of colon mucosal tissues. The glandular structures of the colon mucosal tissue were detected throughout its entire depth, and we accumulated 10 two photon microscopic images at depths of 90–190 µm to visualize the overall H2S distribution. There were variables between normal colon mucosa and inflammatory mucosa of UC patients.

Conclusion

We can obtain the distribution image throughout entire depths in the intact live colon tissue of ulcerative colitis patients. This method using multiphoton microscope maybe a new research tool to understand the role of H2S in disease progression and healing process of inflammation in ulcerative colitis patients.