Review
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Meta-Anal. Mar 28, 2020; 8(2): 78-88
Published online Mar 28, 2020. doi: 10.13105/wjma.v8.i2.78
Hypoxia and oxidative stress: The role of the anaerobic gut, the hepatic arterial buffer response and other defence mechanisms of the liver
Samapriya Pasan Hewawasam
Samapriya Pasan Hewawasam, Department of Physiology, Faculty of Medicine, University of Ruhuna, Galle 80000, Sri Lanka
Author contributions: Hewawasam SP performed the literature review, developed the prototypic view on the effect on hypoxia as a defence mechanism against oxidative stress, and wrote and edited the article.
Conflict-of-interest statement: The author has nothing to disclose.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Samapriya Pasan Hewawasam, MBBS, MD, Freelancing Philosopher, Senior Lecturer, Board Certified Gastroenterologist, Department of Physiology, Faculty of Medicine, University of Ruhuna, Karapitiya, Galle 80000, Sri Lanka. spasanhewawasam@yahoo.com
Received: September 17, 2019
Peer-review started: September 17, 2019
First decision: November 4, 2019
Revised: February 3, 2020
Accepted: February 28, 2020
Article in press: February 28, 2020
Published online: March 28, 2020
Abstract

The liver is considered a vital organ and is the hub for multiple chemical functions, such as intermediary metabolism and the detoxification of ingested toxins, which are essential for the preservation of life, hence, the origin or the word “liver”. The liver has enormous, highly diversified catalytic potential. This enormous catalytic potential generates massive oxidative stress, which is important for the functions of the liver but is detrimental to the viability of the liver. The liver receives approximately 80% of its blood supply from the portal vein, which brings less saturated blood from the gastrointestinal tract. Hepatocytes operate in a relatively hypoxic microenvironment due to this portal inflow. The development of this hypoxic microenvironment of the liver is an important evolutionary adaptation for its detoxification function that is not recognized in the literature as a defence mechanism against the oxidative stress generated during the detoxification process. This review describes liver function in relation to its oxidative catalytic potential and the oxidative stress generated by it as well as the evolutionary defence mechanisms present in the liver against this oxidative stress to provide new insights into liver function.

Keywords: Anaerobic gut lumen, Oxidative stress, Liver defences against oxidative stress, Hepatic arterial buffer response, Hypoxia, Liver function

Core tip: This review presents a prototypic view of the role of hypoxia as a regulator and a defence mechanism against oxidative stress in the gastrointestinal tract, including in the liver. The functional significance of having an anaerobic gut lumen for the preservation of energy sources is described in the article. Furthermore, the significance of the hepatic arterial buffer response in the maintenance of the hypoxic microenvironment of hepatocytes to regulate the oxidative stress generated by the enormous catalytic potential of the liver and other hypoxia-mediated defences against this oxidative stress are described.