Defining physiological normoxia for improved translation of cell physiology to animal models and humans

TY - JOUR

T1 - Defining physiological normoxia for improved translation of cell physiology to animal models and humans

AU - Keeley, Thomas P.

AU - Mann, Giovanni E.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - The extensive oxygen gradient between the air we breathe (PO2 ~21 kPa) and its ultimate distribution within mitochondria (as low as ~0.5-1 kPa) is testament to the efforts expended in limiting its inherent toxicity. It has long been recognised that cell culture undertaken under room air conditions falls short of replicating this protection in vitro. Despite this, difficulty in accurately determining the appropriate O2 level(s) in which to culture cells, coupled with a lack of the technology to replicate and maintain a physiological O2 environment in vitro, has hindered addressing this issue thus far. In this review, we aim to address the current understanding of tissue PO2 distribution in vivo¬, and summarize the attempts made to replicate these conditions in vitro. The state-of-the-art techniques employed to accurately determine O2 levels, as well as the issues associated with reproducing physiological O2 levels in vitro, are also critically reviewed. We aim to provide the framework for researchers to undertake cell culture under O2 levels relevant to specific tissues and organs. We envisage that this review will facilitate a paradigm shift, enabling translation of findings under physiological conditions in vitro to disease pathology and the design of novel therapeutics.

AB - The extensive oxygen gradient between the air we breathe (PO2 ~21 kPa) and its ultimate distribution within mitochondria (as low as ~0.5-1 kPa) is testament to the efforts expended in limiting its inherent toxicity. It has long been recognised that cell culture undertaken under room air conditions falls short of replicating this protection in vitro. Despite this, difficulty in accurately determining the appropriate O2 level(s) in which to culture cells, coupled with a lack of the technology to replicate and maintain a physiological O2 environment in vitro, has hindered addressing this issue thus far. In this review, we aim to address the current understanding of tissue PO2 distribution in vivo¬, and summarize the attempts made to replicate these conditions in vitro. The state-of-the-art techniques employed to accurately determine O2 levels, as well as the issues associated with reproducing physiological O2 levels in vitro, are also critically reviewed. We aim to provide the framework for researchers to undertake cell culture under O2 levels relevant to specific tissues and organs. We envisage that this review will facilitate a paradigm shift, enabling translation of findings under physiological conditions in vitro to disease pathology and the design of novel therapeutics.

KW - physiological normoxia

KW - intracellular oxygen levels

KW - redox signaling

KW - oxygen tension

KW - Cellular biology

KW - vascular biology

KW - Keap1-Nrf2

UR - http://www.scopus.com/inward/record.url?scp=85055601848&partnerID=8YFLogxK

U2 - 10.1152/physrev.00041.2017

DO - 10.1152/physrev.00041.2017

M3 - Review article

SN - 0031-9333

VL - 99

SP - 161

EP - 234

JO - Physiological Reviews

JF - Physiological Reviews

IS - 1

T2 - 19th Society for Free Radical Research International Meeting, Lisboa, Portugal 4-7 June 2018 [Symposium: Molecular Oxygen in Health And Disease: One Tissue’s Hypoxia is Another’s Hyperoxia]

Y2 - 4 June 2018 through 7 June 2018

ER -