HIGH INTRACOLONIC ACETALDEHYDE VALUES PRODUCED BY A BACTERIOCOLONIC PATHWAY FOR ETHANOL OXIDATION IN PIGLETS

Background-Human colonic contents and many colonic microbes produce co nsiderable amounts of acetaldehyde from ethanol in vitro. Aims-To exam ine in piglets if acetaldehyde is produced in the colon also in vivo, and if so, what is the fate of intracolonically formed acetaldehyde. A nimals-Seventeen native, non-fasted female piglets (20-25 kg) were use d. Methods-Six piglets received either 1.5 g/kg bw or 2.5 g/kg bw of e thanol intravenously. In seven piglets, 0.7 g or 1.75 g of ethanol/kg bw was administered intravenously, followed by a subsequent intragastr ic ethanol infusion of 1.8 g/kg bw and 4.5 g/kg bw, respectively. The samples of colonic contents for the assessment of ethanol and acetalde hyde concentrations were obtained up to seven hours, In four additiona l piglets, the intracolonic values of ethanol, acetaldehyde, and aceta te were observed for 60 minutes after an intracolonic infusion of acet aldehyde solution. Results-A raised intracolonic, endogenous acetaldeh yde concentration (mean (SEM); 36 (9) mu M) was found in all piglets b efore ethanol infusion. After the infusion of ethanol, intracolonic et hanol and acetaldehyde values increased in parallel, reaching the peak values 57 (4) mM of ethanol and 271 (20) mu M of acetaldehyde in the group that received the highest dose of ethanol. A positive correlatio n (r=0.45; p<0.001) was found between intracolonic ethanol and acetald ehyde values. Acetaldehyde administered intracolonically was mainly me tabolised to acetate but also to ethanol in the colon, Conclusions-Sig nificant endogenous intracolonic acetaldehyde values can be found in t he normal porcine colon. Furthermore, our results suggest the existenc e of a bacteriocolonic pathway for ethanol oxidation. Increased amount s of acetaldehyde are formed intracolonically from ingested ethanol by this pathway.