The Food Matrix and the Gastrointestinal Fluids Alter the Features of Silver Nanoparticles.

Silver nanoparticles (AgNPs) are used in the agri-food sector, which can lead to their ingestion. Their interaction with food and their passage through the gastrointestinal tract can alter their properties and influence their fate upon ingestion. Therefore, this study aims at developing an in vitro method to follow the fate of AgNPs in the gastrointestinal tract. After incorporation of AgNPs into a standardized food matrix, a precolonic digestion is simulated and AgNPs are characterized by different techniques. The presence of food influences the AgNPs properties by forming a corona around nanoparticles. Even if the salivary step does not impact significantly the AgNPs, the pH decrease and the digestive enzymes induce the agglomeration of AgNPs during the gastric phase, while the addition of intestinal fluids disintegrates these clusters. AgNPs can thus reach the intestinal cells under nanometric form, although the presence of food and gastrointestinal fluids modifies their properties compared to pristine AgNPs. They can form a corona around the nanoparticles and act as colloidal stabilizer, which can impact the interaction of AgNPs with intestinal epithelium. This study demonstrates the importance of taking the fate of AgNPs in the gastrointestinal tract into account to perform an accurate risk assessment of nanomaterials.

Soluble silver ions from silver nanoparticles induce a polarised secretion of interleukin-8 in differentiated Caco-2 cells.

Because of their antimicrobial properties, silver nanoparticles are increasingly incorporated in food-related and hygiene products, which thereby could lead to their ingestion. Although their cytotoxicity mediated by oxidative stress has been largely studied, their effects on inflammation remain controversial. Moreover, the involvement of silver ions (originating from Ag0 oxidation) in their mode of action is still unclear. In this context, the present study aims at assessing the impact of silver nanoparticles on the secretion of the pro-inflammatory chemokine interleukin-8 by Caco-2 cells forming an in vitro model of the intestinal mucosal barrier. Silver nanoparticles induced a vectorized secretion of interleukin-8 towards the apical compartment, which is found in the medium 21 h after the incubation. This secretion seems mediated by Nrf2 signalling pathway that orchestrates cellular defense against oxidative stress. The soluble silver fraction of silver nanoparticles suspensions led to a similar amount of secreted interleukin-8 than silver nanoparticles, suggesting an involvement of silver ions in this interleukin-8 secretion.

Short-term biodistribution and clearance of intravenously administered silica nanoparticles.

Recently, concerns have been raised about potential adverse effects of synthetic amorphous silica, commonly used as food additive (E551), since silica nanoparticles have been detected in food containing E551. We examined the biodistribution and excretion in female Sprague-Dawley rats of NM-200, a well characterized nanostructured silica representative for food applications. A single intravenous injection of NM-200 was applied at a dose of 20 mg/kgbw, followed by autopsy after 6 and 24 h. The main organs where silicon accumulated were liver and spleen. The silicon concentration significantly decreased in spleen between 6 and 24 h. In liver the tendency was the same but the effect was not significant. This could be due to clearance of the spleen to the liver via the splenic vein, while liver clearance takes more time due to hepatic processing and biliary excretion. In treated animals the liver showed in addition a prominent increase of macrophages between both evaluation moments. Within the first 24 h, silicon was mainly excreted through urine. Further studies are necessary to evaluate the toxicokinetics of different types of silica nanomaterials at lower exposure doses in order to be able to predict kinetics and toxicity of silica nanoparticles depending on their physicochemical characteristics.

A combination of NMR and liquid chromatography to characterize the protective effects of Rhus tripartita extracts on ethanol-induced toxicity and inflammation on intestinal cells.

Consumption of ethanol may have severe effects on human organs and tissues and lead to acute and chronic inflammation of internal organs. The present study aims at investigating the potential protective effects of three different extracts prepared from the leaves, root, and stem of the sumac, Rhus tripartita, against ethanol-induced toxicity and inflammation using intestinal cells as a cell culture system, in vitro model of the intestinal mucosa. The results showed an induction of cytotoxicity by ethanol, which was partially reversed by co-administration of the plant extracts. As part of investigating the cellular response and the mechanism of toxicity, the role of reduced thiols and glutathione-S-transferases were assessed. In addition, intestinal cells were artificially imposed to an inflammation state and the anti-inflammatory effect of the extracts was estimated by determination of interleukin-8. Finally, a detailed characterization of the contents of the three plant extracts by high resolution Nuclear Magnetic Resonance (NMR) spectroscopy and mass spectrometry revealed significant differences in their chemical compositions.

In vitro investigation of intestinal transport mechanism of silicon, supplied as orthosilicic acid-vanillin complex.

SCOPE: Silicon (Si) is one of the most abundant trace elements in the body. Although pharmacokinetics data described its absorption from the diet and its body excretion, the mechanisms involved in the uptake and transport of Si across the gut wall have not been established. METHODS AND RESULTS: Caco-2 cells were used as a well-accepted in vitro model of the human intestinal epithelium to investigate the transport, across the intestinal barrier in both the absorption and excretion directions, of Si supplied as orthosilicic acid stabilized by vanillin complex (OSA-VC). The transport of this species was found proportional to the initial concentration and to the duration of incubation, with absorption and excretion mean rates similar to those of Lucifer yellow, a marker of paracellular diffusion, and increasing in the presence of EGTA, a chelator of divalents cations including calcium. A cellular accumulation of Si, polarized from the apical side of cells, was furthermore detected. CONCLUSION: These results provide evidence that Si, ingested as a food supplement containing OSA-VC, crosses the intestinal mucosa by passive diffusion via the paracellular pathway through the intercellular tight junctions and accumulates intracellularly, probably by an uptake mechanism of facilitated diffusion. This study can help to further understand the kinetic of absorption of Si.

Screening of Cytotoxic B. cereus on Differentiated Caco-2 Cells and in Co-Culture with Mucus-Secreting (HT29-MTX) Cells.

B. cereus is an opportunistic foodborne pathogen able to cause diarrhoea. However, the diarrhoeal potential of a B. cereus strain remains difficult to predict, because no simple correlation has yet been identified between the symptoms and a unique or a specific combination of virulence factors. In this study, 70 B. cereus strains with different origins (food poisonings, foods and environment) have been selected to assess their enterotoxicity. The B. cereus cell-free supernatants have been tested for their toxicity in vitro, on differentiated (21 day-old) Caco-2 cells, using their ATP content, LDH release and NR accumulation. The genetic determinants of the main potential enterotoxins and virulence factors (ces, cytK, entFM, entS, hbl, nhe, nprA, piplC and sph) have also been screened by PCR. This analysis showed that none of these genes was able to fully explain the enterotoxicity of B. cereus strains. Additionally, in order to assess a possible effect of the mucus layer in vitro, a cytotoxicity comparison between a monoculture (Caco-2 cells) and a co-culture (Caco-2 and HT29-MTX mucus-secreting cells) model has been performed with selected B. cereus supernatants. It appeared that, in these conditions, the mucus layer had no notable influence on the cytotoxicity of B. cereus supernatants.

Proteomic response of inflammatory stimulated intestinal epithelial cells to in vitro digested plums and cabbages rich in carotenoids and polyphenols.

Due to their anti-oxidant and anti-inflammatory potential, polyphenol and carotenoid-rich plant foods have been suggested as promising phytochemicals in the prevention of or as adjuvants regarding inflammatory bowel diseases (IBD). In the present study, we investigated whether plum (Italian Plum, Prunus cocomilla), or cabbage (Kale, Brassica oleracea var. sabellica), selected for their high phytochemical content, are able to reduce inflammation in cellular models of the intestinal epithelium, employing proteomic methods. For this purpose, plum/cabbage (carotenoid content: 1.9 mg per 100 g resp. 13 mg per 100 g; polyphenol content: 83 mg per 100 g resp. 27 mg per 100 g) were gastro-intestinally digested, and aliquots exposed (18 h) to either a monoculture (Caco-2) or a triple culture (Caco-2/HT-29-MTX (90 : 10, v/v) with THP-1 like macrophages), stimulated (with LPS, TNF-α, and IL-1ß) to induce inflammation. Cells (Caco-2, Caco-2/HT-29-MTX, and THP-1) were then harvested separately, and proteomic analyses of total cell extracts were carried out by 2D-DIGE. In the monoculture, 68 protein-spots were significantly (p < 0.05, expression ratio >1.5) differentially regulated due to the Kale and Italian plum digesta, and in the co-culture 206 protein-spots, compared to digesta without plum/cabbage. These belonged to 27 (monoculture) and 76 (coculture) uniquely identified proteins, suggesting the coculture to be a more sensitive model. Proteins included antioxidant enzymes such as catalase, superoxide dismutase and glutathione-S-transferases. Only 3 proteins were differentially regulated in the THP-1 cells, perhaps as these were only indirectly exposed. The results show promise regarding some aspects related to IBD complications, however, employing phytochemical-rich food items should be further investigated in in vivo trials.

Evaluation of the anti-diarrheal activity of the hydromethanolic root extract of Rhus tripartita (Ucria) (Anacardiacae).

INTRODUCTION: Rhus tripartita (Anacardiacae) is a plant which is traditionally used for the treatment of ulcer and diarrhea in Tunisia. However, the scientific basis for this usage has not been well established. The core aim of the present study is to evaluate the antidiarrheal activity of Rhus tripartita root methanolic extract (RRE). MATERIAL AND METHODS: The antidiarrheal activity of RRE oral doses (50, 100, 200 and 300mg/kg) was evaluated using the castor oil-induced diarrhea, the intestinal fluid emptying method and the normal intestinal transit test. The antibacterial activity was tested against four pathogenic bacteria using two methods. The RRE was also phytochemical studied. RESULTS: Diarrhea experiments showed a protective effect of the RRE which produced a significant (p<0.05) and dose-dependent reduction of all the diarrhea parameters. It delayed the onset of diarrhea, produced a significant decrease in the frequency of defecation and the diarrhea score severity and decreased the volume of intestinal fluid induced by castor oil as well as the propulsion intestinal transit. The effect of the extract at the highest dose (300mg/kg) was similar to that of loperamide, the standard anti-diarrheal drug (10mg/kg). The anti-bacterial activity test showed that RRE exhibited a great inhibition activity against four pathogenic bacteria strains (Esherichia coli, Salmonella typhimurium, Salmonella argenosa, Staphylococcus aureus). Oral administration of the extract up to 3g/kg did not produce any acute toxicity in rats. The preliminary phytochemical screening of the RRE revealed the presence of flavonoids, tannins, and polyphenols. CONCLUSION: Results showed that RRE at 300mg/kg possesses the highest anti-diarrheal activity possibly mediated by the inhibitory effects on gastrointestinal propulsion and intestinal fluid accumulation.

Tuning the inflammatory response to silver nanoparticles via quercetin in Caco-2 (co-)cultures as model of the human intestinal mucosa.

Interaction of nanoparticles with food matrix components may cause unpredictable health complications. Using an improved Caco-2 cell-based in vitro (co-)culture model the potential of quercetin as one of the major food flavonoids to alter the effect of silver nanoparticles (Ag-NPs) <20 nm in the human intestinal mucosa at real life concentrations was investigated. Ag-NPs (15-90 µg/ml) decreased cell viability and reduced thiol groups, induced oxidative/nitrosative stress and lipid peroxidation and led to activity changes of various antioxidant enzymes after 3h exposure. The contribution of Ag(+) ions within the concentrations released from nanoparticles was shown to be less important, compared to Ag-NPs. While leading to inflammatory response in the intestines, Ag-NPs, paradoxically, also showed a potential anti-infammatory effect manifested in down-regulated IL-8 levels. Quercetin, co-administered with Ag-NPs, led to a reduction of cytotoxicity, oxidative stress, and recovered metabolic activity of Caco-2 cells, suggesting the protective effects of this flavonoid against the harmful effect of Ag-NPs. Quercetin not only alleviated the effect of Ag-NPs on the gastrointestinal cells, but also demonstrated a potential to serve as a tool for reversible modulation of intestinal permeability.

Inflammation related responses of intestinal cells to plum and cabbage digesta with differential carotenoid and polyphenol profiles following simulated gastrointestinal digestion.

SCOPE: Plums/cabbages represent fruits/vegetables rich in carotenoids and polyphenols, and have been associated with anti-inflammatory properties. METHODS AND RESULTS: We tested four plum (Italian Plum, Plum 620, Ersinger, and Cherry Plum) and cabbage varieties (Duchy, Kalorama, Kale, Scots Kale) with contrasting carotenoid/polyphenol content for their capability to alter inflammation/oxidative stress following simulated gastrointestinal digestion. Digesta were exposed to Caco-2(TC-7) and to a triple-culture(Caco-2/HT-29-MTX (90:10 v/v) including THP-1 like macrophages), stimulated to induce inflammation (10 µg/mL LPS, 100 ng/mL TNF-α, 25 ng/mL IL-1-ß for 24 h, the last 18 h with digesta). Endpoints investigated included IL-6, IL-8, PGE-2, NO (all ELISA), NF-κB, MAPK, IL-6, IL-8, iNOS, Nrf2, COX-2 (real-time-PCR) and Nrf2 (immunostaining). IL-6 secretion was reduced in THP-1 cells by Scots Kale and Kalorama (up to 22%, p<0.05), and IL-8 secretion in the coculture (up to 35% in plums, p<0.05). This was accompanied by decreased NF-kB expressions in THP-1 cells (up to 30%, p<0.05). Nrf2 translocation to the nucleus was partly reduced by plums and cabbages (up to 40% (p<0.05). CONCLUSIONS: Some varieties, especially in the triple-culture, reduced inflammation, though this was unrelated to concentrations of carotenoids/polyphenols. The potential of phytochemical-rich fruits and vegetables to ameliorate gastrointestinal inflammation should be further investigated.

Carotenoid and polyphenol bioaccessibility and cellular uptake from plum and cabbage varieties.

Plum and cabbage are rich in carotenoids and polyphenols. However, their bioactivity depends on their release and intestinal uptake. Four varieties of Brassicaceae (Duchy, Scots Kale, Kale, Kalorama) and Prunus (Cherry Plum, Plum 620, Ersinger, Italian Plum) were studied; bioaccessibility following in vitro digestion, cellular uptake (Caco-2 vs. co-culture cell model: Caco-2:HT-29-MTX (90:10%) and colonic fermentation were determined for carotenoids/polyphenols; the influence of certain kitchen preparations was likewise studied. Carotenoids were non-significantly influenced by the latter, while for polyphenols, boiling and steaming significantly reduced total phenolics (p<0.05). Carotenoid bioaccessibility did not differ significantly between Prunus vs. Brassicaceae varieties, but xanthophyll was higher than carotene bioaccessibility (p<0.01). Polyphenol bioaccessibility was low (<10%), possibly compromised by the cream containing test meal. Total carotenoid cellular uptake varied between varieties (0.3-4.1%), being higher for carotenes (4.1%) than for xanthophylls (1.6%, p<0.01), and were higher for the co-culture cell model compared to Caco-2 cells (p<0.01). Total carotenoid recovery in the colonic fraction varied from 4% to 25%. Lower bioaccessibility of carotenes thus appeared to be somewhat counterbalanced by higher cellular uptake. The potential positive role of the mucus layer for cellular uptake and the fate of the colonic digesta deserve further attention in the future.

An accurate and sensitive Coomassie Brilliant Blue G-250-based assay for protein determination.

In this protocol we present a rapid and sensitive assay for the accurate determination of protein concentration. The assay is a modification of a previous method, and measures minimum 0.2 µg protein.

Engineered nanomaterials in food: implications for food safety and consumer health.

From the current state-of-the-art, it is clear that nanotechnology applications are expected to bring a range of benefits to the food sector aiming at providing better quality and conservation. In the meantime, a growing number of studies indicate that the exposure to certain engineered nanomaterials (ENMs) has a potential to lead to health complications and that there is a need for further investigations in order to unravel the biological outcomes of nanofood consumption. In the current review, we summarize the existing data on the (potential) use of ENMs in the food industry, information on the toxicity profiles of the commonly applied ENMs, such as metal (oxide) nanoparticles (NPs), address the potential food safety implications and health hazards connected with the consumption of nanofood. A number of health complications connected with the human exposure to ENMs are discussed, demonstrating that there is a real basis for the arisen concern not only connected with the gut health, but also with the potency to lead to systemic toxicity. The toxicological nature of hazard, exposure levels and risk to consumers from nanotechnology-derived food are on the earliest stage of investigation and this review also highlights the major gaps that need further research and regulation.

Carotenoids, polyphenols and micronutrient profiles of Brassica oleraceae and plum varieties and their contribution to measures of total antioxidant capacity.

The consumption of phytochemicals such as carotenoids and polyphenols within whole fruits and vegetables has been associated with decreased incidence of various inflammation and oxidative stress related chronic diseases, which may be due to direct antioxidant effects, or indirect mechanisms such as affecting signal transduction/gene expression. Within the present study, we investigated the antioxidant composition of two major groups of vegetables and fruits, Brassica oleraceae and prunus spp., and estimated their contribution to antioxidant capacity. For this purpose, 17 plum and 27 Brassica varieties were collected in Luxembourg, and analysed for their individual polyphenol and carotenoid profile, vitamin C, dietary fibre, and minerals/trace elements, and their correlation with markers of antioxidant capacity (FRAP, ABTS, Folin-Ciocalteu). Total carotenoid and polyphenol content varied considerably between the different Brassica and plum varieties, with highest concentrations in the variety Kale (13.3 ± 0.58 mg/100g wet weight) and Cherry plum (1.96 ± 0.28 mg/100g) for carotenoids; and Kale (27.0 ± 0.91 mg/100g) and Kirks plum (185 ± 14 mg/100g) for polyphenols. In developed multiple linear-regression-models for Brassica, flavonoids, anthocyanins, lutein and vitamin C were found to be the best predictors of antioxidant capacity as assessed by FRAP (R(2)=0.832) and flavonoids, neochlorogenic acid and vitamin C as assessed by ABTS (R(2)=0.831); while for plums these were selenium, total sugars, chlorogenic acid and vitamin C (R(2)=0.853), and selenium, chlorogenic acid and flavonoids for FRAP (R(2)=0.711). When considering Brassica and plum consumption in Luxembourg, it is estimated that both contribute to an antioxidant intake equivalent to 26 and 6 mg per day of ascorbic acid equivalents, respectively.

Stem cell bioprocess engineering towards cGMP production and clinical applications.

Stem cells, including mesenchymal stem cells and pluripotent stem cells, are becoming an indispensable tool for various biomedical applications including drug discovery, disease modeling, and tissue engineering. Bioprocess engineering, targeting large scale production, provides a platform to generate a controlled microenvironment that could potentially recreate the stem cell niche to promote stem cell proliferation or lineage-specific differentiation. This survey aims at defining the characteristics of stem cell populations currently in use and the present-day limits in their applications for therapeutic purposes. Furthermore, a bioprocess engineering strategy based on bioreactors and 3-D cultures is discussed in order to achieve the improved stem cell yield, function, and safety required for production under current good manufacturing practices.

The anti-inflammatory effect of a pomegranate husk extract on inflamed adipocytes and macrophages cultivated independently, but not on the inflammatory vicious cycle between adipocytes and macrophages.

Obese adipose tissues contain a higher proportion of inflamed macrophages than the normal adipose tissue. Adipocytes and macrophages are known to secrete pro-inflammatory markers that establish the systemic inflammation leading to metabolic complications. CCL-2 secreted by hypertrophied adipocytes attracts and activates macrophages in the adipose tissue. These cells, in turn, secrete TNFα and other pro-inflammatory molecules. The pomegranate husk extract and its phenolic constituents, punicalagin and ellagic acid, have exhibited an anti-inflammatory effect. In this study, we used an in vitro coculture system of 3T3-L1 murine adipocytes and RAW 264.7 macrophages to investigate the potential anti-inflammatory effects of these compounds on the vicious cycle between both cell types. The pomegranate husk extract presented an anti-inflammatory effect on the inflamed cells cultivated independently, as suggested by a decrease of (i) CCL-2 secretion by both cell types, (ii) adipocyte IL-6 expression and secretion, and (iii) macrophage TNFα secretion. Nevertheless and surprisingly, no anti-inflammatory effect was observed in coculture. Punicalagin, at the same concentration as that found in the pomegranate extract, had a more potent effect than the extract and in coculture; it reduced significantly the IL-6 secretion. Ellagic acid decreased TNFα and CCL-2 macrophage secretion, CCL-2 adipocyte secretion and, in coculture, it reduced IL-6 secretion and expression by adipocytes. These results indicate that the pomegranate husk extract has an anti-inflammatory action on adipocytes and macrophages but seems to be not able to reduce the inflammatory vicious cycle between both cells. Ellagitannin and punicalagin showed a better effect on inflammation suggesting that PHE will be a good candidate for more investigations.

Single-cell force spectroscopy of pili-mediated adhesion.

Although bacterial pili are known to mediate cell adhesion to a variety of substrates, the molecular interactions behind this process are poorly understood. We report the direct measurement of the forces guiding pili-mediated adhesion, focusing on the medically important probiotic bacterium Lactobacillus rhamnosus GG (LGG). Using non-invasive single-cell force spectroscopy (SCFS), we quantify the adhesion forces between individual bacteria and biotic (mucin, intestinal cells) or abiotic (hydrophobic monolayers) surfaces. On hydrophobic surfaces, bacterial pili strengthen adhesion through remarkable nanospring properties, which - presumably - enable the bacteria to resist high shear forces under physiological conditions. On mucin, nanosprings are more frequent and adhesion forces larger, reflecting the influence of specific pili-mucin bonds. Interestingly, these mechanical responses are no longer observed on human intestinal Caco-2 cells. Rather, force curves exhibit constant force plateaus with extended ruptures reflecting the extraction of membrane nanotethers. These single-cell analyses provide novel insights into the molecular mechanisms by which piliated bacteria colonize surfaces (nanosprings, nanotethers), and offer exciting avenues in nanomedicine for understanding and controlling the adhesion of microbial cells (probiotics, pathogens).

Polyunsaturated fatty acid metabolism in enterocyte models: T84 cell line vs. Caco-2 cell line.

Human colon carcinoma cell lines such as Caco-2 cells, model of mature enterocytes and T84 cells, model of crypt cells are useful to study interactions between nutrient processing and metabolic functions at intestinal level. Our study aimed at comparing the ability of Caco-2 and T84 cells (1) to incorporate dietary polyunsaturated fatty acids (PUFA), (2) to process them and (3) to sort them into neutral lipids (NL), free fatty acids (FFA) and phospholipids (PL). Caco-2 and T84 cells were exposed to a 7-day long supplementation with PUFA. The amounts of fatty acids accumulated and incorporated into the NL, FFA or PL fractions were higher in Caco-2 than in T84 cells. Caco-2 cells were able to significantly elongate C18 PUFA and C20 PUFA of both n-3 and n-6 families. In contrast, T84 cells were unable to elongate the n-6 fatty acids whereas elongation of n-3 fatty acids was detectable but marginal. Similarly, a Δ6 desaturase activity was observed in Caco-2 but not in T84 cells. In T84 cells, each exogenous fatty acid was predominantly accumulated in the PL fraction. In Caco-2 cells, C20 fatty acids and C18:2n-6 was preferentially accumulated in the PL fraction, while C22 PUFA and C18:3n-3 was preferentially accumulated in the NL fraction. Overall, this study has shown that Caco-2 and T84 cells, as models of intestinal mucosal cells, present large differences in PUFA accumulation capacity, specific elongase and desaturase activities and distribution pattern of exogenous PUFA and of their metabolites in the lipid classes.

In vitro toxicity assessment of silver nanoparticles in the presence of phenolic compounds--preventive agents against the harmful effect?

The increasing commercial use of silver nanoparticles (Ag-NPs) will inevitably lead to elevated silver exposure and thus to potential human health complications. In this study the acute toxicity of Ag-NPs <20 nm alone and upon co-administration with food matrix component phenolic compounds (PCs) on the cell-based models of the gastrointestinal tract was investigated. An improved co-culture model of Caco-2 and RajiB cells was applied for more precise in vitro simulation of the gastrointestinal tract. The involvement of two major factors contributing to the toxicity of Ag-NPs, i.e. the release of Ag(+) and the induction of oxidative stress, was investigated. Ag-NPs were cytotoxic for Caco-2 cells with an EC50 of ca. 40 µg/ml. Ag-NPs led to oxidative stress starting from ca. 45 µg/ml. The epithelial barrier integrity disruption by Ag-NPs on Caco-2 cell mono- and co-cultures was established by decreased transepithelial electrical resistances and increased passages of Lucifer Yellow, a paracellular marker. Immunofluorescence staining demonstrated that Ag-NPs affect occludin and zonula occludens 1 distributions, suggesting the opening of tight junctions. Ag(+), corresponding to the release from Ag-NPs, demonstrated a partial contribution in the toxic parameters, induced by Ag-NPs. Two PCs, quercetin and kaempferol, partially protected the Caco-2 cells from Ag-NP-induced toxicity and maintained the epithelial barrier integrity, disrupted by NPs. No protective effect was observed for resveratrol. The protective effect could be beneficial and decrease the potential toxicity of ingested Ag-NPs. However, the precise mechanisms of barrier-integrity-destabilising action of Ag-NPs/Ag(+) and protective effect of PCs still require further elucidation.

A dried yeast fermentate selectively modulates both the luminal and mucosal gut microbiota and protects against inflammation, as studied in an integrated in vitro approach.

EpiCor, derived from Saccharomyces cerevisiae, has been shown to have immunomodulating properties in human clinical trials and in vitro. However, the underlying mechanisms behind its immune protection via the gut remain largely unknown. Therefore, the aim of this study was to use an integrated in vitro approach to evaluate the metabolism of EpiCor by the intestinal microflora, its modulating effect on the gut microbiota, and its anti-inflammatory activity on human-derived cell lines. Using the SHIME model, in combination with a mucus adhesion assay, has shown that low doses of EpiCor have a prebiotic-like modulatory effect on the luminal- and mucosa-associated microbiota. These include gradual changes in general community structure, reduction of potential pathogens, quantitative increase in lactobacilli, and qualitative modulation of bifidobacteria. Moreover, by combination of the SHIME with Caco-2 cells and Caco-2/THP1 cocultures, a significant decrease in pro-inflammatory cytokines was observed at the end of the treatment period.