Lactobacillus rhamnosus Strain GG Reduces Aflatoxin B ₁ Transport, Metabolism, and Toxicity in Caco-2 Cells

Abstract

The probiotic Lactobacillus rhamnosus GG is able to bind the potent hepatocarcinogen aflatoxin B 1 (AFB 1 ) and thus potentially restrict its rapid absorption from the intestine. In this study we investigated the potential of GG to reduce AFB 1 availability in vitro in Caco-2 cells adapted to express cytochrome P-450 (CYP) 3A4, such that both transport and toxicity could be assessed. Caco-2 cells were grown as confluent monolayers on transmembrane filters for 21 days prior to all studies. AFB 1 levels in culture medium were measured by high-performance liquid chromatography. In CYP 3A4-induced monolayers, AFB 1 transport from the apical to the basolateral chamber was reduced from 11.1% ؎ 1.9% to 6.4% ؎ 2.5% (P ‫؍‬ 0.019) and to 3.3% ؎ 1.8% (P ‫؍‬ 0.002) within the first hour in monolayers coincubated with GG (1 ؋ 10 10 and 5 ؋ 10 10 CFU/ml, respectively). GG (1 ؋ 10 10 and 5 ؋ 10 10 CFU/ml) bound 40.1% ؎ 8.3% and 61.0% ؎ 6.0% of added AFB 1 after 1 h, respectively. AFB 1 caused significant reductions of 30.1% (P ‫؍‬ 0.01), 49.4% (P ‫؍‬ 0.004), and 64.4% (P < 0.001) in transepithelial resistance after 24, 48, and 72 h, respectively. Coincubation with 1 ؋ 10 10 CFU/ml GG after 24 h protected against AFB 1 -induced reductions in transepithelial resistance at both 24 h (P ‫؍‬ 0.002) and 48 h (P ‫؍‬ 0.04). DNA fragmentation was apparent in cells treated only with AFB 1 cells but not in cells coincubated with either 1 ؋ 10 10 or 5 ؋ 10 10 CFU/ml GG. GG reduced AFB 1 uptake and protected against both membrane and DNA damage in the Caco-2 model. These data are suggestive of a beneficial role of GG against dietary exposure to aflatoxin.

Protective Effects of Lactobacillus rhamnosus GG on Aflatoxins-Induced Toxicities in Male Albino Mice

“…These data are consistent with other experimental studies which had evidenced the ability of lactobacilli and bifidobacteria to decrease the genotoxic activity of some chemical compounds [32,77,78]. Gratz et al [79] used DNA fragmentation as a marker of AFB 1 -induced DNA damage in differentiated Caco-2 cells exposed to AFB 1 following induction of CYP 3A4 . DNA damage was apparent following treatment with AFB 1 , while coincubation with LGG reduced the AFB 1 -induced damage in this test system.…”

“…This might be, in part, due to the ability of lactic acid bacteria to adsorb this mycotoxin; where several studies clearly reported the adsorption mechanisms in vitro [24,79,89]. Previous work showed that LGG was the most efficient strain in binding a range of mycotoxins, including aflatoxins [27].…”

The role of biomarkers in evaluating human health concerns from fungal contaminants in food

“…These epithelial cells are tightly bound by intercellular junctional complexes, which regulate the paracellular permeability, and thus maintain epithelial integrity. In confluent Caco-2 monolayers, a cell line that mimics the intestinal barrier, aflatoxin appears to affect the integrity of the monolayer by modulating paracellular transport (124) . Thus, aflatoxin may further exacerbate dietary restricted individuals, and perhaps prolong a cycle of poor nutrient retention, extended gastrointestinal infection, and enteropathy.…”

Probiotic Lactobacillus rhamnosus Reduces Organophosphate Pesticide Absorption and Toxicity to Drosophila melanogaster

“…There have been developments within bioremediation research to investigate the potential of transitory food-grade bacteria to prophylactically prevent the absorption of environmental toxins, such as pesticides (22), heavy metals (23), and aflatoxin (24,25). Many lactobacilli are commonly used in fermented foods, such as yogurt, cheese, sauerkraut, pickles, beer, wine, cider, kimchi, cocoa, and kefir (26).…”