Alcohol Dehydrogenase Activities in the Human Gastric Mucosa: Effects of Helicobacter pylori Infection, Sex, Age, and the Part of the Stomach

Effect of H. pylori Infection on Cytokine Profiles and Oxidative Balance in Subjects with Chronic Alcohol Ingestion

Different amounts of ingested alcohol can have distinct effects on the human body. However, there is limited research on chronic alcohol consumption with Helicobacter pylori infection. We sought to investigate the relationship between the cytokine profile, oxidative balance and H. pylori infection in subjects with chronic alcohol consumption. A total of 142 subjects were divided into three groups: 59 subjects with chronic alcohol ingestion and H. pylori infection (group A); 53 subjects with chronic alcohol ingestion without H. pylori infection (group B); and 30 control subjects (group C). The serum levels of CagA, interleukin (IL)-10, E-selectin, TNF-α, malondialdehyde (MDA) and superoxide dismutase (SOD) activity were measured by enzyme-linked immunosorbent assay (ELISA). We found that the ages and serum H. pylori CagA levels among the three groups, as well as both the mean drinking age and the mean daily alcohol consumption between groups A and B, were matched and comparable. Comparing the BMIs among the three groups, the BMI differences were found to be statistically significant (F=3.921, P<0.05). Compared with group C, the BMIs in groups A and B were significantly higher (P<0.001 and P<0.01, respectively); however, the BMI differences between group A and group B were not statistically significant (P>0.05). Additionally, no differences in the serum CagA levels were found in comparisons among the groups (all P>0.05). The serum IL-10 and E-selectin levels in group A were significantly lower than those in group B (serum IL-10: P<0.05; E-selectin: P<0.05). The serum IL-10 in group A was significantly higher than that in group C (P<0.01); the serum E-selectin levels in group A did not significantly differ compared with those in group C (P>0.05). Furthermore, the serum IL-10 and E-selectin levels in group B were significantly higher than those in group C (serum IL-10: P<0.001; E-selectin: P<0.05); however, the serum TNF-α levels did not differ among groups (all P>0.05). Although the serum levels of MDA and SOD in groups A and B were slightly lower than those in group C, there were no significant differences among groups (all P>0.05). In conclusion, we believe that H. pylori infection might cause a significant inhibition of certain cytokine profiles in subjects with chronic alcohol ingestion. Moreover, chronically ingested alcohol may exert an adjusted inflammatory effect, but there was no association between H. pylori infection, chronic alcohol consumption and oxidative balance.

Species and inter-individual differences in metabolic capacity of di(2-ethylhexyl)phthalate (DEHP) between human and mouse livers

OBJECTIVES

This study was conducted to assess inter-species and inter-individual differences in the metabolism of di(2-ethylhexyl)phthalate (DEHP) in humans and mice.

METHODS

The activities of four DEHP-metabolizing enzymes [lipase, UDP-glucuronocyltransferase (UGT), alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH)] were measured in the livers of 38 human subjects of various ages and in eight 129/Sv male mice.

RESULTS

Microsomal lipase activity was significantly lower in humans than in mice. The V max/K m value in humans was one-seventh of that in mice, microsomal UGT activity in humans was a sixth of that in mice, and cytosolic ALDH activity for 2-ethylhexanal in humans was one-half of that in mice. In contrast, ADH activity for 2-ethylhexanol was twofold higher in humans than in mice. The total amount of DEHP urinary metabolites and the concentration of mono(2-ethylhexyl)phthalate (MEHP) were much higher in intact mice than in the U.S. general population based on data reported elsewhere, regardless of the similar estimated DEHP intake between these mice and the human reference population. However, mono(2-ethyl-5-oxo-hexyl)phthalate (5oxo-MEHP) and mono(2-ethyl-5-carboxypentyl)phthalate (5cx-MEPP) levels were higher in the latter than in the former. Of note, inter-subject variability in the activities of all enzymes measured was 10-26-fold.

CONCLUSION

The inter-individual variation in the metabolism of DEHP in humans may be greater than the difference between mice and humans (inter-species variation), and both may affects the risk assessment of DEHP.

Alcohol dehydrogenase (ADH) isoenzyme activity in the sera of patients with Helicobacter pylori infection

Human gastric mucosa contains three classes of alcohol dehydrogenase (ADH) isoenzymes: I, III, and IV. Various factors have been found to influence gastric ADH activity. One of them is Helicobacter pylori infection, which is associated with gastric mucosal injury and leads to a decrease in gastric ADH activity. The aim of the study was to assess the effect of H. pylori infection on the serum activity of ADH isoenzymes. Serum samples were taken from 35 patients with H. pylori infection and from 35 healthy subjects. For measurement of class I isoenzyme activity we employed the fluorometric method, with class-specific fluorogenic substrate (4-methoxy-1-naphthaldehyde). The activities of class III and IV ADH isoenzymes were measured by the photometric method with formaldehyde and with m-nitrobenzaldehyde as substrate, respectively. Total activity of ADH was measured by a photometric method with p-nitrosodimethylaniline. The total activities of ADH and class IV isoenzyme were significantly higher in sera of patients with H. pylori infection compared to healthy subjects. The serum activity of other tested isoenzymes of ADH did not differ significantly between infected and noninfected groups. We conclude that H. pylori infection of gastric mucosa is reflected in the serum by a significant increase in class IV and total ADH activity.

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

BACKGROUND

The gastric mucosal alcohol dehydrogenase activity was reported to be reduced in subjects with Helicobacter pylori-associated chronic gastritis. However, the role of H. pylori infection in the metabolism of ingested ethanol has not been fully elucidated.

AIM

To clarify whether H. pylori infection exerts any influence on the metabolism of small amounts of ethanol in humans.

SUBJECTS AND METHODS

13C-ethanol (100 microL) diluted in 100 mL water was administered orally to 22 healthy volunteers before breakfast. Breath samples were then collected every 10 min for up to 60 min. The content of 13CO2 (per thousand) was analysed using a mass-spectrometric method. The excretion rate of labelled CO2 was analysed by calculation of the following mathematical parameters, i.e., Tmax, Cmax, and AUC60.

RESULTS

In H. pylori-negative controls (n = 11), the Tmax, Cmax and AUC60 were 0.47 +/- 0.13, 19.1 +/- 6.0 and 13.7 +/- 4.5, respectively. The corresponding values were 0.53 +/- 0.16 (n.s.) and 12.7 +/- 4.8 (P < 0.05) and 9.0 +/- 3.6 (P < 0.05), respectively, in subjects with H. pylori infection (n = 11). Successful eradication of H. pylori was associated with significant increase of these parameters (Cmax)and AUC60, n = 6).

CONCLUSIONS

The metabolism of small amounts of ethanol is attenuated in subjects with H. pylori infection.