<i>Helicobacter pylori</i> Infection Decreases Gastric Alcohol Dehydrogenase Activity and First-Pass Metabolism of Ethanol in Man

Abstract

Background/Aims: Ethanol is metabolized by alcohol dehydrogenase in the human stomach. This metabolism contributes to the so-called first-pass metabolism of ethanol which is affected by gender, medication, and morphological alterations of the gastric mucosa. Recently, it has been shown that Helicobacter pylori is capable to oxidize ethanol to acetaldehyde in vitro. Since H. pylori also injures gastric mucosa, the present study examines the effect of this bacterium on gastric alcohol dehydrogenase activity and systemic availability of ethanol in vivo. Methods: Thirteen volunteers (7 men and 6 women, aged 18–52 years) with gastric H. pylori infection diagnosed by a positive CLO test and positive gastric histology received ethanol (0.225 g/kg) either orally or intravenously before and after H. pylori elimination to determine systemic availability of ethanol. In addition, gastric biopsy specimens were taken from all subjects before and after H. pylori elimination for histological assessment of mucosal alterations and determinations of gastric alcohol dehydrogenase activity and phenotype of the enzyme. Results: In the presence of H. pylori the first-pass metabolism of ethanol was found to be significantly reduced (625 ± 234 vs. 1,155 ± 114 mg/dl/min, p = 0.046). This reduction of first-pass metabolism of ethanol was associated with a significant decrease in alcohol dehydrogenase activity (4.8 ± 1.5 vs. 12.1 ± 2.3 nmol/mg protein × min, p < 0.05) and an increase in the severity of mucosal damage as determined by a histological score (p < 0.05). Conclusions: H. pylori infection leads to gastric mucosal injury which is associated with a decrease in gastric alcohol dehydrogenase activity and first-pass metabolism of ethanol. Ethanol metabolism by H. pylori does not play an important role in vivo. However, gastric morphology is one important factor determining systemic availability of ethanol in man.

Alcohol Dehydrogenase (ADH) Isoenzyme Activity in the Sera of Patients with Helicobacter pylori Infection

“…When we measured total ADH activity in gastric mucosa we did not find significant differences between infected and noninfected samples [9]. In contrast, various authors have found a low gastric ADH activity in the presence of H. pylori infection [21][22][23]. In this study the total activity of ADH was significantly higher in sera of H. pylori-positive patients than in sera of controls.…”

Effect of Helicobacter pylori Infection on the Activity of Class I, III and IV Alcohol Dehydrogenase in the Human Stomach

“…However, the change of class IV ADH isoenzyme activity was not accompanied by the change in total ADH activity. Other authors, who measured total ADH activity with ethanol as a substrate, showed the decrease of enzyme activity in H. pylori -positive samples [8, 9, 10]. …”

“…According to various authors, the gastric ADH activity was significantly lower in the presence of H. pylori infection [8, 9, 10]. It was also documented that chronic gastritis associated with H. pylori predominates in the antrum of the stomach [8, 9, 10, 11].…”

“…It was also documented that chronic gastritis associated with H. pylori predominates in the antrum of the stomach [8, 9, 10, 11]. Histological study in alcoholic patients also showed a higher incidence of chronic gastritis in the antrum [12].…”

13C‐ethanol breath test reveals impaired alcohol metabolism in patients with Helicobacter pylori infection

“…The observation which we found is compatible to the report of Simanowski et al, who showed that mucosal ADH activity and first-pass metabolism of alcohol were reduced in subjects with H. pylori infection of the gastric mucosa when compared with those in non-infected subjects. 21 They evaluated first-pass metabolism by measuring the systemic availability of ethanol after administration of ethanol (0.225 g/kg body weight) either orally or intravenously. This dose is approximately 200-times higher than that employed in the present study in 60-kg body weight subjects.…”