Role of Intestinal Microbiota in Ulcerative Colitis

More documents

Recommendations

Info

Summary Summary The microbiota of the human intestinal tract is complex with variable populations of bacteria who are either permanent gut residents (commensal bacteria) or transient inhabitants introduced from the environment. The commensal bacteria are believed to be important for human health due to actions such as protection against pathogens, induction of immune regulatory functions and nutrient processing. Hence, the composition of commensal bacteria is important to preserve colonic health. Ulcerative colitis (UC) is an inflammatory bowel disease and dysbiosis in the composition of commensals has been reported, which could affect colonic health. In the experimental part of this thesis, the fecal microbiota derived from UC patients in either remission or with active disease and healthy subjects was quantified using quantitative Real‐Time PCR (qPCR) to examine the microbiota composition. The results demonstrated that the microbiota composition was different in UC patients in relapse compared to healthy subjects and the difference could be ascribed Gram‐ negative bacteria, hence indicating that an altered microbiota composition is associated with colonic inflammation. Additionally, results revealed that the microbiota composition in remission either resembled the composition in healthy or in relapse, demonstrating that the microbiota in remission is unstable. The mucus layer lining the epithelium of the intestinal tract is important for the protection of the epithelium in humans. The commensal bacteria that colonize the colonic mucus are suggested to play an important role in stimulating regulatory immune responses compared to luminal bacteria, since they reside closer to the intestinal epithelial cells. The ability of fecal microbiota derived from healthy subjects and UC patients to colonize mucus was examined in a study of this thesis to elucidate, if the adhesion capacity is different depending on disease state. For this purpose, an in vitro dynamic gut model was used. Several bacterial taxa from both lumen and mucus were quantified using qPCR. The results revealed that the bacterial community of the mucus differed from that of the lumen and that lactobacilli and bifidobacteria derived from UC patients had a significant decreased capacity to colonize mucus than observed for similar bacterial groups originating from healthy subjects. This suggests that the inflammatory state in UC may influence the adhesion capacity of commensal bacteria such as beneficial Gram‐positive bacteria lactobacilli and bifidobacteria. VI
Summary Maintenance of a benign gut microbial composition may help decrease risk of mucosal inflammation in UC. This could be achieved by the consumption of prebiotics (include non‐ digestible carbohydrates), which are defined as “selectively fermented ingredients that cause specific changes in composition and/or activity in the gastointestinal microbiota, which confer benefits upon host well‐being and health.” In the experimental part of this thesis, in vitro fermentation studies were performed using fecal samples from human volunteers either healthy and/or UC patients to investigate prebiotic properties of novel carbohydrate preparations. The results revealed that incubation with arabino‐ oligosaccharides (DP2‐10) from sugar beet pulp could selectively stimulate fecal lactobacilli and bifidobacteria from UC patients. This may suggest protective properties of arabino‐ oligosaccharides against UC. In addition, in vitro fermentation studies demonstrated that high molecular weight fractions of galactose or arabinose chains either from potato or sugar beet pulp, respectively, selectively stimulated the growth of fecal bifidobacteria derived from healthy subjects. The prebiotic properties demonstrated by the high molecular weight carbohydrate preparations in vitro could be of importance in vivo, since long‐chain carbohydrates may be fermented slowly by beneficial colonic bacteria, thus penetrating prebiotic effect all the way throughout the colon. VII
Page 1: Role of Intestinal Microbiota in Ul
Page 4 and 5: Role of Intestinal Microbiota in Ul
Page 6 and 7: Preface Preface This thesis present
Page 10 and 11: Dansk sammendrag Dansk sammendrag M
Page 12 and 13: Introduction and objectives Introdu
Page 14 and 15: List of Manuscripts Not included in
Page 16 and 17: List of contents List of Centents P
Page 18 and 19: List of Centents Methodology append
Page 21 and 22: 1. The intestinal environment Theor
Page 23 and 24: Theoretical part 5 1. The intestina
Page 25 and 26: 2. The colonic environment Theoreti
Page 27 and 28: Theoretical part 9 2. The colonic e
Page 29 and 30: Table 1: The presence of glycoside
Page 31 and 32: Theoretical part Figure 3: The colo
Page 33 and 34: 3. Inflammatory Bowel disease Theor
Page 35 and 36: Theoretical part 17 3. Inflammatory
Page 37 and 38: Theoretical part 19 4. Modulation o
Page 43 and 44: Table 4: Clinical trials on the pre
Page 45 and 46: Theoretical part 5. Production of p
Page 51: Methodology part
Page 54 and 55: Methodology part 6. Methodology, co
Page 56 and 57: Methodology part 6. Methodology, co
Page 58 and 59:
Methodology part 6. Methodology, co
Page 60 and 61:
Introduction Methodology part 42 Pa
Page 62 and 63:
Abstract Background Detailed knowle
Page 64 and 65:
depending the level of disease acti
Page 66 and 67:
in 1 x TAE at 60 °C for 16 h at 36
Page 68 and 69:
Statistics PCA were generated by SA
Page 70 and 71:
The PCA of the Gram‐positive bact
Page 72 and 73:
layer of UC patients and found that
Page 74 and 75:
Acknowledgements The authors thank
Page 76 and 77:
Table 2 ‐ 16S rRNA gene and 16S
Page 78 and 79:
1. Firmicutes phylum 2. Bacteroidet
Page 80 and 81:
Supplementary Figure S1. Dice clust
Page 82 and 83:
Reference List 1. Ahmed S, Macfarla
Page 84 and 85:
32. Matsuki T, Watanabe K, Fujimoto
Page 87 and 88:
Methodology part Paper 2 Fecal lact
Page 89 and 90:
Fecal lactobacilli and bifidobacter
Page 91 and 92:
Introduction The mucus layer lining
Page 93 and 94:
efore enrolment and there was no si
Page 95 and 96:
(Bio‐Rad Labs, Hercules, Californ
Page 97 and 98:
Microbial community analysis using
Page 99 and 100:
difference from the luminal microbi
Page 101 and 102:
that C. coccoides group and C. lept
Page 103 and 104:
Table 1 ‐ 16S rRNA gene of phylum
Page 105 and 106:
Table 2 ‐ Preference of bacterial
Page 107 and 108:
Figure 1. A) Schematic overview of
Page 109 and 110:
A. B. Figure 3. Principal component
Page 111 and 112:
15. Fooks LJ, Gibson GR. (2002) In
Page 113 and 114:
47. Ouwehand AC, Suomalainen T, Tol
Page 115 and 116:
Methodology part Paper 3 Paper 3 In
Page 117 and 118:
APPLIED AND ENVIRONMENTAL MICROBIOL
Page 119 and 120:
8338 VIGSNÆS ET AL. APPL. ENVIRON.
Page 121 and 122:
Page 123 and 124:
Page 125:
Page 128 and 129:
Methodology part Introduction The a
Page 130 and 131:
Journal of Agricultural and Food Ch
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 139 and 140:
Methodology part Paper 5 Paper 5 Ma
Page 141 and 142:
Appl Microbiol Biotechnol (2011) 90
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Methodology part Paper 6 Tailored e
Page 155 and 156:
Process Biochemistry 46 (2011) 1039
Page 157 and 158:
Table 1 List of enzymes. Enzyme Sou
Page 159 and 160:
J. Holck et al. / Process Biochemis
Page 161 and 162:
Intensity 50 0 C1 175.05 J. Holck e
Page 163 and 164:
J. Holck et al. / Process Biochemis
Page 165:
[29] Bauer S, Vasu P, Persson S, Mo
Page 168 and 169:
Methodology part 150
Page 170 and 171:
Methodology part 152 Appendix 1 hor
Page 172 and 173:
Appendix 3 Methodology part Appendi
Page 174 and 175:
Methodology part 156 Appendix 3
Page 177 and 178:
7. Discussion and perspectives Disc
Page 179 and 180:
Discussion and conclusion 161 7. Di
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
References References Abreu,M.T., V
Page 187 and 188:
References Derrien,M., Vaughan,E.E.
Page 189 and 190:
References Haarman,M. and Knol,J. (
Page 191 and 192:
References Lantz,P.G., Matsson,M.,
Page 193 and 194:
References Matsuki,T., Watanabe,K.,
Page 195 and 196:
References Pullan,R.D., Thomas,G.A.
Page 197 and 198:
References Tannock,G.W. (2010). Ana
Page 200:
National Food Institute Technical U
show all

Role of Intestinal Microbiota in Ulcerative Colitis

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?