title: Dietary xylooligosaccharide downregulates IFN-γ and the low-grade inflammatory cytokine IL-1β systemically in mice.
abstract: Dietary carbohydrates improve growth conditions for distinct populations of bacteria that may affect mucosal and systemic immunity. In this study, we fed in a parallel experiment a 10% xylooligosaccharide (XOS)-supplemented diet or a control diet to 2 groups of male C57BL/6NTac mice for 10 wk from weaning. We found that the XOS diet significantly increased Bifidobacterium throughout the intestine compared with control-fed mice, with the highest proportions found in the ileum after XOS feeding (P < 0.001). In the intestinal epithelium, most innate immune-related genes were unaffected by XOS feeding, whereas expression of interleukin 1β (Il1β) (P < 0.01) and interferon γ (Ifnγ) (P < 0.05) was significantly less in blood from XOS-fed mice than from control-fed mice. In vitro treatment of blood with propionate significantly decreased Il1β (P < 0.01), Ifnγ (P < 0.01), and interleukin 18 (Il18) (P < 0.001) expression, supporting our hypothesis that increased production of short-chain fatty acids (SCFAs) in the gut, which are transported across the intestine and into the systemic compartments, results in downregulation of low-grade inflammatory cytokines. The defensin regenerating islet-derived protein 3γ (RegIIIγ) was significantly more highly expressed in the small intestine (P < 0.01) in XOS-fed mice compared with control-fed mice, suggesting only minor contact between bifidobacteria and epithelial cells. In support of this, the SCFA-induced sodium/hydrogen exchanger isoform 3 expression tended to be greater in the XOS group than in the control group (P = 0.06), indicating an indirect SCFA-mediated antiinflammatory effect of XOS. In conclusion, XOS feeding decreases systemic inflammation, and this effect is most likely caused by higher SCFA concentrations as a result of an increased bifidobacterial saccharolytic fermentation in the entire gut and not only in the large intestine.
authors: Section of Biomedicine, Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark. camfriis@sund.ku.dk
authors: Camilla H F
authors: CH
authors: Hansen
authors: Hanne
authors: H
authors: Frøkiær
authors: Annette G
authors: AG
authors: Christensen
authors: Anders
authors: A
authors: Bergström
authors: Tine R
authors: TR
authors: Licht
authors: Axel K
authors: AK
authors: Hansen
authors: Stine B
authors: SB
authors: Metzdorff
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents; D001644:Bifidobacterium / Q000254:growth & development / Q000378:metabolism; D004032:Diet; D015536:Down-Regulation / Q000187:drug effects*; D005285:Fermentation; D015870:Gene Expression / Q000187:drug effects; D005965:Glucuronates / Q000008:administration & dosage*; D007109:Immunity / Q000235:genetics; D007371:Interferon-gamma / Q000097:blood* / Q000235:genetics; D053583:Interleukin-1beta / Q000097:blood* / Q000235:genetics; D007422:Intestines / Q000382:microbiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009844:Oligosaccharides / Q000008:administration & dosage*
chemical_list: D000893:Anti-Inflammatory Agents; D005965:Glucuronates; D053583:Interleukin-1beta; D009844:Oligosaccharides; C570991:xylooligosaccharide; D007371:Interferon-gamma