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Am J Physiol Cell Physiol. 2015 Sep 15;309(6):C350-60. doi: 10.1152/ajpcell.00191.2015. Epub 2015 Jul 15.

Physiologic hypoxia and oxygen homeostasis in the healthy intestine. A Review in the Theme: Cellular Responses to Hypoxia.

Author information

1
Department of Medicine and Mucosal Inflammation Program, University of Colorado School of Medicine, Aurora, Colorado.
2
Department of Medicine and Mucosal Inflammation Program, University of Colorado School of Medicine, Aurora, Colorado sean.colgan@ucdenver.edu.

Abstract

In recent years, the intestinal mucosa has proven to be an intriguing organ to study tissue oxygenation. The highly vascularized lamina propria juxtaposed to an anaerobic lumen containing trillions of metabolically active microbes results in one of the most austere tissue microenvironments in the body. Studies to date have determined that a healthy mucosa contains a steep oxygen gradient along the length of the intestine and from the lumen to the serosa. Advances in technology have allowed multiple independent measures and indicate that, in the healthy mucosa of the small and large intestine, the lumen-apposed epithelia experience Po2 conditions of <10 mmHg, so-called physiologic hypoxia. This unique physiology results from a combination of factors, including countercurrent exchange blood flow, fluctuating oxygen demands, epithelial metabolism, and oxygen diffusion into the lumen. Such conditions result in the activation of a number of hypoxia-related signaling processes, including stabilization of the transcription factor hypoxia-inducible factor. Here, we review the principles of mucosal oxygen delivery, metabolism, and end-point functional responses that result from this unique oxygenation profile.

KEYWORDS:

barrier function; colon; hypoxia; intestine; metabolism

PMID:
26179603
PMCID:
PMC4572369
DOI:
10.1152/ajpcell.00191.2015
[Indexed for MEDLINE]
Free PMC Article

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