Essentially, the hygiene hypothesis argues a lower infection price may be the underlying reason behind the increasing incidence of autoimmune diseases such as for example UC due to having less protection against immunological disorders completed by specific infectious agents 80. a rudimentary area of the intestine. In the past few years, nevertheless, many research have got recommended its immunological importance for the advancement and preservation from the intestinal disease fighting capability 1. The appendix has been shown to have an important conversation with the intestinal flora 2, 3, 4. Considering the appendix as a safe house for the commensal gut flora, these studies hypothesize that commensal bacteria can be reintroduced from the appendix in case of disease, and therefore the appendix can be considered as an important a part of Eribulin intestinal health. This literature review assesses the current knowledge concerning the immunological aspects of the vermiform appendix. By describing its normal physiology and the importance of its biofilm, and appraising its evolution and elucidating which aspects have changed or, more importantly, which have been preserved in the long history of its presence, a clearer understanding of its influence around the intestinal immune system will be provided. The evolutionary perspective In attempting to discover a plausible function of the human appendix, there has been a search for homology with that of other mammalians. The fact that this appendix is much larger in Rabbit Polyclonal to VASH1 certain lower mammalians such as rabbits has, for a long time, resulted in the human appendix being considered a vestigial organ. The lack of a clear morphological caecal appendage in some evolutionarily more closely related primates, however, seems to contradict this hypothesis 5. In the assessment of its evolution, the human appendix is generally considered as a remnant of the mammalian caecum. Originally, this part of the intestine had a digestive function, primarily Eribulin facilitating the digestion of cellulose with the aid of residential micro\organisms 6. This cellulose digestive trait is lost in the human caecum, although in the human appendix Eribulin a relative abundance of micro\organisms present in biofilms still exists alongside the presence of lymphoid tissue 3. The vermiform appendix in rabbits is found to be essential for the development of the gut associated lymphoid tissue (GALT). After the initial independent development of follicle centres, presence of the commensal intestinal flora is required for diversification of the primary antibody repertoire and for further development of T and B cell areas Eribulin of follicles within the lymphoid tissue 7, 8, 9. In some non\human primates, such as tamarins and white\eyelid mangabeys 5, and other mammals such as mice 10 and rats 11 that lack a caecal diverticulum, a high concentration of lymphoid tissue is found in the caecal apex 5, referred to as the caecal patch. Moreover, the proximal large bowel of amphibians and reptiles, that lack both the presence of a caecum and appendix and the need of cellulose digestion, also functions as the site where most of the conversation between host and symbiotic bacteria is seen 12. This gives rise to the idea that this appendix, with Eribulin its excellent conditions for sheltering the commensal gut flora, may have evolved prior to the caecum, rather than having derived from it. Therefore, the digestive trait could have been developed in conjunction with the bulging of the proximal large intestine that eventually became the caecum, which would imply that the immunological function existed before the digestive one. The worm\like morphology of the appendix and its location in the gut could indicate its long\lasting immunological function by providing a safe house for the commensal intestinal flora, instead of being evidence for its vestigial nature 3, 12. Functional histology of the appendix Similar to the intestinal wall of the colon, the appendiceal wall consists of a mucosa, submucosa, muscularis externa and serosa (Fig. ?(Fig.1).1). Within these layers, however, the presence, quantity and function of cells differ between the appendix and colon, illustrated most notably by the presence of lymphoid follicles in the submucosa and lamina propria of the appendiceal wall 13. The characteristics of cells and molecules found in human appendix are summarized.