Characterizing microbiota-independent effects of oligosaccharides on intestinal epithelial cells: insight into the role of structure and size : Structure-activity relationships of non-digestible oligosaccharides.
OBJECTIVE
The direct effects of galacto-oligosaccharides (GOS), including Vivinal®GOS syrup (VGOS) and purified Vivinal®GOS (PGOS), on the epithelial integrity and corresponding interleukin-8 (IL-8/CXCL8) release were examined in a Caco-2 cell model for intestinal barrier dysfunction. To investigate structure-activity relationships, the effects of individual DP fractions of VGOS were evaluated. Moreover, the obtained results with GOS were compared with Caco-2 monolayers incubated with fructo-oligosaccharides (FOS) and inulin.


METHODS
Caco-2 monolayers were pretreated (24 h) with or without specific oligosaccharides or DP fractions of VGOS (DP2 to DP6) before being exposed for 12 or 24 h to the fungal toxin deoxynivalenol (DON). Transepithelial electrical resistance and lucifer yellow permeability were measured to investigate barrier integrity. A calcium switch assay was used to study the reassembly of tight junction proteins. Release of CXCL8, a typical marker for inflammation, was quantified by ELISA.


RESULTS
In comparison with PGOS, FOS and inulin, VGOS showed the most pronounced protective effect on the DON-induced impairment of the monolayer integrity, acceleration of the tight junction reassembly and the subsequent CXCL8 release. DP2 and DP3 in concentrations occurring in VGOS prevented the DON-induced epithelial barrier disruption, which could be related to their high prevalence in VGOS. However, no effects of the separate DP GOS fractions were observed on CXCL8 release.


CONCLUSIONS
This comparative study demonstrates the direct, microbiota-independent effects of oligosaccharides on the intestinal barrier function and shows the differences between individual galacto- and fructo-oligosaccharides. This microbiota-independent effect of oligosaccharides depends on the oligosaccharide structure, DP length and concentration.
Division of Veterinary Pharmacology, Pharmacotherapy and Toxicology, Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 104, 3584 CM, Utrecht, The Netherlands.|Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences Faculty of Science, Utrecht University, 3584 CG, Utrecht, The Netherlands.
Peyman
P
Akbari
Division of Veterinary Pharmacology, Pharmacotherapy and Toxicology, Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 104, 3584 CM, Utrecht, The Netherlands.
Johanna
J
Fink-Gremmels
Laboratory of Food Chemistry, Wageningen University, 6708 WG, Wageningen, The Netherlands.
Rianne H A M
RHAM
Willems
Laboratory of Food Chemistry, Wageningen University, 6708 WG, Wageningen, The Netherlands.
Elisabetta
E
Difilippo
Laboratory of Food Chemistry, Wageningen University, 6708 WG, Wageningen, The Netherlands.
Henk A
HA
Schols
FrieslandCampina, 3818 LE, Amersfoort, The Netherlands.
Margriet H C
MHC
Schoterman
Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences Faculty of Science, Utrecht University, 3584 CG, Utrecht, The Netherlands.|Nutricia Research, 3584 CT, Utrecht, The Netherlands.
Johan
J
Garssen
Division of Veterinary Pharmacology, Pharmacotherapy and Toxicology, Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 104, 3584 CM, Utrecht, The Netherlands. S.braber@uu.nl.
Saskia
S
Braber
D018938:Caco-2 Cells; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000382:microbiology; D000069196:Gastrointestinal Microbiome; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D007422:Intestines / Q000166:cytology* / Q000382:microbiology; D007444:Inulin / Q000494:pharmacology; D009844:Oligosaccharides / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014255:Trichothecenes / Q000633:toxicity
C508606:CXCL8 protein, human; D016209:Interleukin-8; D009844:Oligosaccharides; D014255:Trichothecenes; D007444:Inulin; C007262:deoxynivalenol
CXCL8; Caco-2 cells; Degree of polymerization; Intestinal permeability; Non-digestible oligosaccharides; Tight junctions