Tohoku J. Exp. Med., 2018 April, 244(4)

Detection of Acetaldehyde in the Esophageal Tissue among Healthy Male Subjects after Ethanol Drinking and Subsequent L-Cysteine Intake

HIDEKI OKATA,¹ WAKU HATTA,¹ KATSUNORI IIJIMA,² KIYOTAKA ASANUMA,¹ ATSUKI TSURUYA,³ NAOKI ASANO,¹ TOMOYUKI KOIKE,¹ SHIN HAMADA,¹ TORU NAKAYAMA,³ ATSUSHI MASAMUNE¹ and TOORU SHIMOSEGAWA¹

¹Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
²Department of Gastroenterology and Neurology, Akita University Graduate School of Medicine, Akita, Akita, Japan
³Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi, Japan

Ethanol is oxidized by alcohol dehydrogenase to acetaldehyde, a recognized carcinogen for the esophagus. However, no previous study has measured the acetaldehyde levels in the esophageal tissue. L-cysteine has been shown to reduce the acetaldehyde levels in the saliva; however, it is unknown whether L-cysteine intake affects the acetaldehyde concentration in the esophageal tissue. The aim of this study was to measure the acetaldehyde concentration in the esophageal tissue after ethanol drinking and evaluate the effect of L-cysteine intake on the acetaldehyde levels in the esophagus. We enrolled 10 male subjects with active acetaldehyde dehydrogenase-2*1/*1 (ALDH2*1/*1) genotype and 10 male subjects with the inactive acetaldehyde dehydrogenase-2*1/*2 (ALDH2*1/*2) genotype, the mean ages of whom were 25.6 and 27.9 years, respectively. In this prospective, single-blind, placebo-controlled study using L-cysteine and placebo lozenges (first and second examination), saliva and blood were collected before and after ethanol drinking. Esophageal tissue was obtained by endoscopic biopsy at 60 minutes after drinking, and the acetaldehyde and ethanol concentrations were measured. The acetaldehyde concentration of the saliva was significantly lower in those taking L-cysteine than in those taking the placebo. Acetaldehyde in the esophageal tissue was detected only in those taking L-cysteine lozenges. There were no correlations between the acetaldehyde concentrations in the esophageal tissue and saliva or blood. In conclusion, we detected acetaldehyde in the human esophageal tissue after ethanol drinking. Unexpectedly, intake of L-cysteine lozenges appears to contribute to detection of acetaldehyde in the esophageal tissue.

keywords —— acetaldehyde; acetaldehyde dehydrogenase; esophageal tissue; L-cysteine; placebo.

© 2018 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2018, 244, 317-325

Correspondence: Waku Hatta, Division of Gastroenterology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan.

e-mail: waku-style@festa.ocn.ne.jp