More homogeneous capillary flow and oxygenation in deeper cortical layers correlate with increased oxygen extraction
- Massachusetts General Hospital, United States
- University of Pennsylvania, United States
- University of California, San Diego, United States
- École Polytechnique de Montréal, Canada
- Aarhus University, Denmark
Abstract
Our understanding of how capillary blood flow and oxygen distribute across cortical layers to meet the local metabolic demand is incomplete. We addressed this question by using two-photon imaging of resting-state microvascular oxygen partial pressure (PO2) and flow in the whisker barrel cortex in awake mice. Our measurements in layers I-V show that the capillary red-blood-cell flux and oxygenation heterogeneity, and the intracapillary resistance to oxygen delivery, all decrease with depth, reaching a minimum around layer IV, while the depth-dependent oxygen extraction fraction is increased in layer IV, where oxygen demand is presumably the highest. Our findings suggest that more homogeneous distribution of the physiological observables relevant to oxygen transport to tissue is an important part of the microvascular network adaptation to local brain metabolism. These results will inform the biophysical models of layer-specific cerebral oxygen delivery and consumption and improve our understanding of the diseases that affect cerebral microcirculation.
Data availability
All data generated or analyzed during this study are included in this paper and the supporting files.
Article and author information
Author details
Sergei A Vinogradov
Funding
National Institutes of Health (NS091230)
- Sava Sakadžić
National Institutes of Health (MH111359)
- Sava Sakadžić
National Institutes of Health (EB018464)
- Sava Sakadžić
National Institutes of Health (NS092986)
- Sava Sakadžić
National Institutes of Health (NS055104)
- Sava Sakadžić
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All animal surgical and experimental procedures were conducted following the Guide for the Care and Use of Laboratory Animals and approved by the Massachusetts General Hospital Subcommittee on Research Animal Care (Protocol No.: 2007N000050).
Copyright
© 2019, Li et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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More homogeneous capillary flow and oxygenation in deeper cortical layers correlate with increased oxygen extraction
eLife 8:e42299.
https://doi.org/10.7554/eLife.42299
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