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. Author manuscript; available in PMC: 2022 Jun 1.
Published in final edited form as: J Leukoc Biol. 2020 Oct 5;109(6):1045–1061. doi: 10.1002/JLB.3RI0620-405RR

Figure 1. Alterations in the intestinal epithelium and immune cells with advanced age.

Figure 1.

The intestinal epithelium is arranged into crypts and villi. Crypt base columnar stem cells reside at the base of the crypt and asymmetrically divide to give rise to stem cells and rapidly dividing cells that make up the transit amplifying region, which differentiate as they move up the crypt. The +4 label retaining, or “reserve,” stem cells reside at the boundary between the crypt base columnar stem cells and the transit amplifying region and can repopulate the crypt base columnar stem cells if they are lost. As the host enters advanced age, a multitude of changes occur, leading to overall increased inflammation.

GIP: Glucose-dependent insulinotropic polypeptide/gastric inhibitory polypeptide

ILC : Innate lymphoid cell

IgA : Immunoglobulin A