Caco 2 Cell

The aim of the present study was to improve the synthetic pathway of bioreversible dipeptide derivatives as well as evaluate the potential of using l-Glu-Sar as a pro-moiety for delivering three newly synthesised nucleoside and pyrimidine l-Glu-Sar derivatives. l-Glu(trans-2-thymine-1-yl-tetrahydrofuran-3-yl ester)-Sar (I), l-Glu(thymine-1-yl-methyl ester)-Sar (II) and l-Glu(acyclothymidine)-Sar (III) were synthesised and in vitro stability was studied in various aqueous and biological media. Affinity to and translocation via hPEPT1 was investigated in mature Caco-2 cell monolayers, grown on permeable supports. Affinity was estimated in a competition assay, using [14C] labelled Gly-Sar (glycylsarcosine). Translocation was measured as pHi-changes induced by the substrates using the fluorescent probe BCECF and an epifluorescence microscope setup. All dipeptide derivatives released the model drugs quantitatively by specific base-catalysed hydrolysis at pH > 6.0. II was labile in aqueous buffer solution, whereas I and III showed appropriate stability for oral administration. In 10% porcine intestinal homogenate, the half-lives of the dipeptide derivatives indicated limited enzyme catalyzed degradation. All compounds showed good affinity to hPEPT1, but the Compounds I and III showed not to be translocated by hPEPT1. The translocation of the l-Glu-Sar derivative of acyclovir, l-Glu(acyclovir)-Sar was also investigated and showed not to take place. Consequently, l-Glu-Sar seems to be a poor pro-moiety for hPEPT1-mediated transport.

D-alpha-tocopheryl poly(ethylene glycol) 1000 succinate (TPGS 1000) is a widely used form of vitamin E. TPGS 1000 is comprised of a hydrophilic polar (water-soluble) head and a lipophilic (water-insoluble) alkyl tail. TPGS 1000 has been used as a solubilizer, an emulsifier and as a vehicle for lipid-based drug delivery formulations. Most recently, TPGS 1000 has been recognized as an effective oral absorption enhancer. An enhancing effect is consistent with a surfactant-induced inhibition of P-glycoprotein (P-gp), and perhaps other drug transporter proteins; however, the exact inhibition mechanism(s) remain unclear. Therefore, in an attempt to generate additional knowledge, we have synthesized and tested various TPGS analogs containing different PEG chain length (TPGS 200/238/400/600/1000/2000/3400/3500/4000/6000). These results demonstrate a relationship between TPGS PEG chain length and influence on rhodamine 123 (RHO) transport in Caco-2 monolayers, a relationship which may be illustrated using a Weibull distribution.

The aim of this study was to investigate the adhesive phenotype of the human intestinal isolate Bifidobacterium bifidum MIMBb75 to human colon carcinoma cell lines. We have previously shown that the adhesion of this strain to Caco-2 cells is mediated by an abundant surface lipoprotein named BopA. In this study, we found that this strain adheres to Caco-2 and HT-29 cells, and that its adhesion strongly depends on the environmental conditions, including the presence of sugars and bile salts and the pH. Considerably more adhesion to a Caco-2 monolayer occurred in the presence of fucose and mannose and less when MIMBb75 grew in Oxgall bile salts compared to standard environmental conditions. In particular, growth in Oxgall bile salts reduced the adhesion ability of MIMBb75 and modified the SDS-PAGE profile of the cell wall associated proteins of the strain. The pH markedly affected both adhesion to Caco-2 and bacterial autoaggregation. Finally, experiments with sodium metaperiodate suggested that not only proteinaceous determinants are involved in the adhesion process of B. bifidum. In conclusion, it seems that the colonization strategy of this bacterium can be influenced by factors varying along the gastrointestinal tract, such as the presence of specific sugars and bile salts and the pH, possibly limiting the adhesion of B. bifidum to only restricted distal sites of the gut.

Twenty-nine Lactobacillus strains of dairy origin were examined in vitro for their probiotic potential. Only a few strains were able to survive at pH 1 or in the presence of pepsin, while all were unaffected by pH 3, pancreatin and bile salts. Strains exhibited variable bile salt hydrolase activity. None was haemolytic. The majority of strains were resistant to vancomycin

... 2.4. Characterization of phage resistant mutants. Phage resistance stability (Carminati, Zennaro, Neviani, & Giraffa, 1993) and adsorption rates (Neviani, Carminati, & Giraffa, 1992) were determined to characterize the phage resistance phenotype of the variants isolated. ...

Micronutrient malnutrition, especially selenium (Se), iron (Fe), and zinc (Zn) deficiency, is a major global health problem. Previous attempts to prevent micronutrient malnutrition through food fortification, supplementation, and enrichment of staple crops has had limited success. Canadian grown lentils are rich in micronutrients Fe (73–90 mg kg−1), Zn (44–54 mg kg−1), Se (425–673 μg kg−1), and have very low concentrations of phytic acid (2.5–4.4 mg g−1). Our preliminary studies using a Caco-2 cell model show that the uptake of Fe from lentils is relatively greater than that of most other staple food crops. Moreover, preliminary results from our human nutrition study in Sri Lanka show an increased trend in blood Se concentration after lentil consumption. This article briefly overviews our previously published results as well as data from international lentil field trials, and describes the potential for biofortified lentil to provide a whole food solution to combat global human micronutrient malnutrition.

Caco-2 cells, an intestinal cell line derived from a human colorectal carcinoma that spontaneously differentiates under standard culture conditions, lends it- self to the in vitro study of human gut in view of its efficient intestinal transport processes. Among its multi- ple biological functions are those related to the absorp- tion, transport, and metabolism of lipids and lipoproteins. Despite their

Vitamin D is enzymatically modified to more than 35 metabolites. While many of these are thought to represent degradation products, some have been shown to exhibit biological activity. We tested whether 3-epi-1α,25-dihydroxyvitamin D3 (3-epi-1α,25(OH)2D3), 1α,25-dihydroxy-24-oxo-vitamin D3 (1α,25(OH)2-24-oxo-D3), and 1α,25(OH)2D3-26,23-lactone can stimulate transcription of vitamin D responsive genes. MC3T3-E1 cells transfected with a 25-hydroxyvitamin D 24-hydroxylase (CYP24) promoter construct displayed a