Toward noninvasive quantification of adipose tissue oxygenation with MRI
- 30 March 2020
- journal article
- research article
- Published by Springer Science and Business Media LLC in International Journal of Obesity
- Vol. 44 (8), 1776-1783
- https://doi.org/10.1038/s41366-020-0567-x
Abstract
Molecular oxygen (O2) plays a key role in normal and pathological adipose tissue function, yet technologies to measure its role in adipose tissue function are limited. O2 is paramagnetic and, in principle, directly influences the magnetic resonance (MR) 1H longitudinal relaxation rate constant of lipids, R1; thus, we hypothesize that MR imaging (MRI) can directly measure adipose O2 via a simple measure of R1. R1 was measured in a 4.7T preclinical MRI system at discrete oxygen partial pressure (pO2) levels. These measures were made in vitro in an idealized system and in vivo in subcutaneous and visceral white adipose of rodents. pO2 was determined using an invasive fiber-optic oxygen monitor. From the MRI and fiber optic data we determined the “relaxivity” of O2 in lipid, a critical parameter in converting the MRI-based R1 measurement into pO2. We used breathing gas challenge to estimate the changes in lipid pO2 (ΔpO2). The relaxivity of O2 in lipid was determined to be 1.7·10−3 ± 4·10−4 mmHg−1s−1 at 4.7T and 37 °C, and was consistent between in vitro and in vivo adipose tissue. There was a strong, significant correlation between MRI- and gold standard OxyLite-based measurements of lipid ΔpO2 for in vivo visceral and subcutaneous fat depots in rodents. This study lays the foundation for a direct, noninvasive measure of adipose pO2 using MRI and will allow for noninvasive measurement of O2 flux in adipose tissue. The proposed approach would be of particular importance in the interrogation of the pathogenesis of type 2 diabetes, where it has been suggested that adipose tissue hypoxia is an independent driver of insulin resistance pathway.Keywords
This publication has 44 references indexed in Scilit:
- Mapping of oxygen by imaging lipids relaxation enhancement: A potential sensitive endogenous MRI contrast to map variations in tissue oxygenationMagnetic Resonance in Medicine, 2012
- Optical probes and techniques for O2 measurement in live cells and tissueCellular and Molecular Life Sciences, 2012
- Adipose tissue remodeling and obesityJCI Insight, 2011
- Brown fat as a therapy for obesity and diabetesCurrent Opinion in Endocrinology, Diabetes and Obesity, 2010
- PET Imaging of HypoxiaPET Clinics, 2009
- Emerging role of adipose tissue hypoxia in obesity and insulin resistanceInternational Journal of Obesity, 2008
- Validation of oxygen extraction fraction measurement by qBOLD techniqueMagnetic Resonance in Medicine, 2008
- Proton imaging of siloxanes to map tissue oxygenation levels (PISTOL): a tool for quantitative tissue oximetryNMR in Biomedicine, 2008
- Oxygen determination in oxygen-supersaturated drinking waters by NMR relaxometryWater Research, 2003
- Bayesian analysis. II. Signal detection and model selectionJournal of Magnetic Resonance (1969), 1990