Colonic biogeography in health and ulcerative colitis

Abstract

The relevance of biogeography to the distal gut microbiota has been investigated in both health and inflammatory bowel disease (IBD), however multiple factors, including sample type and methodology, microbiota characterization and interpersonal variability make the construction of a core model of colonic biogeography challenging. In addition, how phylogenetic classification relates to immunogenicity and whether consistent alterations in the microbiota are associated with ulcerative colitis (UC) remain open questions. This addendum seeks to review the human colonic microbiota in health and UC as currently understood, in the broader context of the human microbiome.

Keywords: Biogeography; inflammatory bowel disease; microbiome; microbiota; spatial ecology; ulcerative colitis.

Figure 1.

Clear distinctions exist between the microbial communities in different body habitats. However, within the same body habitat, variation between individuals can be much larger than variations between different niches or locations within that habitat.

Figure 2.

Interpersonal variation is a characteristic feature in health and UC (A), with significant overlap between health (green-blue figures) and UC (yellow-red figures). Within healthy individuals, bigeography may relate to radial or longitdunal distributions, while local inflammation is an additional feature that could influence the biogeography in UC (B).