Oxidation of Ethanol to Acetaldehyde by Bronchopulmonary Washings: Role of Bacteria

Abstract

The synergistic effects of tobacco smoking and alcohol consumption on the incidence of upper respiratory cancer may be linked to their common ability to produce acetaldehyde, an irritant and potential mutagen. Since alcohol consumption in most individuals results in very low concentrations of acetaldehyde in the blood, we determined whether bronchopulmonary cellular components are capable of oxidizing ethanol to acetaldehyde. We found that significant production of acetaldehyde occurred in vitro after incubation of human bronchopulmonary washings with 25 mM ethanol. Acetaldehyde production was increased in active smokers and related to microorganisms in the bronchopulmonary tract. It was abolished by preincubation of the washings with antibiotics and was reproduced in vitro with Streptococcus pneumoniae. Normal pulmonary cells in bronchopulmonary washings did not produce acetaldehyde from ethanol.

Role of Yeasts in the Salivary Acetaldehyde Production From Ethanol Among Risk Groups for Ethanol‐Associated Oral Cavity Cancer

“…It has been shown that acetaldehyde can be formed in vitro from ethanol by the incubation of human bronchopulmonary washings, and in vivo in the mouth washes of ethanol-rinsing volunteers, both thought to be of bacterial origin Miyakawa et al, 1986;Pikkarainen et al, 1981). The mean acetaldehyde production in saliva has been shown to be -120 pM, but it can reach values up to 600 pM when incubated in vitro for 90 min with ethanol (Homann et al, 1998).…”

Removal of acetaldehyde from saliva by a slow‐release buccal tablet of L‐cysteine

“…9 In addition to the tissue alcohol dehydrogenase (ADH)-mediated ethanol metabolism, gastrointestinal tract bacteria and oral cavity microflora are also able to oxidize ethanol by their ADH-enzyme, 10 and accordingly, particularly high concentrations of acetaldehyde are found in the saliva and in the contents of the large intestine during ethanol oxidation. [11][12][13][14] Cysteine, a nonessential amino acid, has been shown to be able to react covalently with acetaldehyde to form 2-methylthiazolidine-4-carboxylic acid. 15 Thereby, cysteine could prevent acetaldehyde to interact with cellular proteins and DNA, which might interfere with normal cellular functions including acetaldehydeinduced carcinogenesis.…”

Acetaldehyde Production and Other ADH‐Related Characteristics of Aerobic Bacteria Isolated From Hypochlorhydric Human Stomach

“…Associating with prolonged and delayed exposure to acetaldehyde, alcoholics with cancer of oropharynx, larynx, esophagus, stomach, colon, and lungs had markedly higher frequencies of the mutant ALDH2*1/*2 genotype than cancer-free alcoholics (Yokoyama et al, 1998). Interestingly, microbial acetaldehyde production from ethanol has been described in all these organs (Homann et al, 1997a;Jokelainen et al, 1996;Miyakawa et al, 1986;Pikkarainen et al, 1981;Väkeväinen et al, 2000b). Thus, this human "knockout model" for deficient acetaldehyde removal provides strong evidence for the local carcinogenic action of acetaldehyde in humans.…”

“…Marked microbial acetaldehyde production from ethanol has been described in vitro by incubating human bronchopulmonary washings (Pikkarainen et al, 1981) and in vivo in mouthwashes of ethanol-rinsing volunteers (Miyakawa et al, 1986) and both in the saliva (Homann et al, 1997a) and in the hypochlorhydric stomach after moderate alcohol ingestion (Väkeväinen et al, 2000b). In addition to microbial origin, acetaldehyde may be produced from ethanol in the upper digestive tract by mucosal ADHs and/or parotid glands (Dong et al, 1996;Moreno and Parés, 1991;Väkeväinen et al, 2000a;Yin et al, 1993).…”