Title: P-199 The Brown Algae-derived Polysaccharides Laminarin and Fucoidan Alleviate Histopathology and Inflammation in a Porcine Model of Ulcerative Colitis
Abstract: Aberrant regulation of inflammatory processes at the colonic mucosa is a characteristic of ulcerative colitis (UC), which results in over-production of pro-inflammatory cytokines, eliciting damage to surrounding tissues and loss of gastrointestinal function. The brown algae-derived polysaccharides laminarin, a β-(1-3,1-6)-linked glucan, and fucoidan, a sulfated polymeric fucose, have demonstrated immunomodulatory effects on porcine colonic mucosae, including down-regulation of the expression of cytokines. We hypothesised that prior exposure to laminarin and/or fucoidan may alleviate the onset of histopathology and inflammation in a dextran sulphate sodium (DSS) porcine model of UC. A complete randomised design experiment comprising 5 treatment groups was conceived. Pigs (n = 7 per group) were offered diets from weaning (d0) until 18 kg (d35). Treatments groups were: 1) Control diet (CON-DSS), 2) Control diet+DSS (CON+DSS), 3) Fucoidan+DSS (FUC+DSS), 4) Laminarin+DSS (LAM+DSS), 5) Fucoidan + Laminarin +DSS (FUCLAM+DSS). Proportions of fucoidan (240 mg/kg diet) and laminarin (300 mg/kg) were optimised in previously studies. At d35, DSS was administered by oral-gavage for 7d to induce UC in pigs, which were euthanized on d8. Xylose was administered by oral-gavage 2 hour prior to euthanasia to assess increases in serum xylose as a marker of loss of gastrointestinal function. Upon euthanasia, tissue was recovered from the proximal colon for histopathology and cytokine gene expression. Presence and severity of UC was assessed by a pathologist. Expression of a panel of cytokines including IL-8 and IL-6 was assessed using quantitative RT-PCR. The CON+DSS group had a lower final bodyweight compared to the CON-DSS group (21.7kg versus 24.3 kg; P < 0.05), with intermediate values for the DSS groups receiving fucoidan (FUC + DSS: 22.7kg), and the fucoidan/laminarin combination (FUCLAM+DSS: 23.4 kg). Assessment of colonic histopathology confirmed onset of UC in the CON+DSS group when compared to the CON-DSS group (P = 0.015). Interestingly, the severity of colonic histopathology was lessened in groups receiving laminarin and/or fucoidan and was not significantly different to the CON-DSS group. The CON+DSS group had lower serum xylose concentrations (2.86 mg/dL) compared to the CON-DSS group (5.78 mg/dL; P < 0.05). However, groups receiving fucoidan and/or laminarin had comparable levels of serum xylose with the CON-DSS group; (FUC+DSS: 4.30, LAM+DSS: 3.85 & FUCLAM+DSS: 4.06 mg/dL). In the CON+DSS group, there was greater IL-6 gene expression levels in the colonic mucosa compared to the CON-DSS group (P = 0.001). Interestingly, groups containing fucoidan and/or laminarin had lower levels of IL-6 expression which were not significantly different to the CON-DSS group. With regard to IL-8 expression, the FUC+DSS group had lower (P < 0.05) gene expression in the colon compared to the CON+DSS group. Diets containing fucoidan and the fucoidan/laminarin combination alleviated bodyweight-loss, serum xylose, histopathology and IL-6 gene expression which are characteristic of UC. This suggests that these seaweed extracts support gastrointestinal function and have the potential to alleviate the onset of UC in a DSS porcine model of UC. These seaweed derived dietary supports maybe of interest as an adjunct to mainstream UC therapeutics.
Publication Year: 2013
Publication Date: 2013-11-18
Language: en
Type: article
Indexed In: ['crossref']
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