TY - JOUR
T1 - Functional optical coherence tomography at altitude
T2 - retinal microvascular perfusion and retinal thickness at 3,800 meters
AU - Baker, Jacquie
AU - Safarzadeh, Mohammad A.
AU - Incognito, Anthony V.
AU - Jendzjowsky, Nicholas G.
AU - Foster, Glen E.
AU - Bird, Jordan D.
AU - Raj, Satish R.
AU - Day, Trevor A.
AU - Rickards, Caroline A.
AU - Zubieta-DeUrioste, Natalia
AU - Alim, Usman
AU - Wilson, Richard J.A.
N1 - Funding Information:
This work was funded by a University of Calgary URGC Grant (to R.J.A.W.), Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery grants (to T.A.D.: RGPIN-2016–04915; to R.J.A.W.: RGPIN-2015–03941). Additional financial support was provided by the Alberta Government Student Temporary Employment Program and NSERC Undergraduate Student Research Assistantships. Salary support was obtained from the Canadian Institutes of Health Research (CIHR), Libin Cardiovascular Institute Post-Doctoral Fellowship in Women’s Cardiovascular Health and the NSERC Brain CREATE Program (to J.B.), CIHR Post-Doctoral Fellowship (to A.V.I.), Alberta Innovates Graduate Scholarship, NSERC Brain CREATE, T. Chen Fong Scholarship in Medical Imaging Science and T. Chen Fong Research Excellence Scholarship (to M.A.S.), the Parker B. Francis Post-Doctoral Fellowship and NSERC BRAIN CREATE Program (to N.G.J.), and CIHR (to S.R.R.). American Heart Association Grant-in-Aid was provided to C.A.R. (17GRNT33671110).
Funding Information:
The authors thank all our study volunteers for their time and effort in participating in our study as well as the staff at the White Mountain Research Station. This work was funded by a University of Calgary URGC Grant (to R.J.A.W.), Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery grants (to T.A.D.: RGPIN-2016–04915; to R.J.A.W.: RGPIN-2015–03941). Additional financial support was provided by the Alberta Government Student Temporary Employment Program and NSERC Undergraduate Student Research Assistantships. Salary support was obtained from the Canadian Institutes of Health Research (CIHR), Libin Cardiovascular Institute Post-Doctoral Fellowship in Women’s Cardiovascular Health and the NSERC Brain CREATE Program (to J.B.), CIHR Post-Doctoral Fellowship (to A.V.I.), Alberta Innovates Graduate Scholarship, NSERC Brain CREATE, T. Chen Fong Scholarship in Medical Imaging Science and T. Chen Fong Research Excellence Scholarship (to M.A.S.), the Parker B. Francis Post-Doctoral Fellowship and NSERC BRAIN CREATE Program (to N.G.J.), and CIHR (to S.R.R.). American Heart Association Grant-in-Aid was provided to C.A.R. (17GRNT33671110).
Publisher Copyright:
© 2022 the American Physiological Society.
PY - 2022/9
Y1 - 2022/9
N2 - Cerebral hypoxia is a serious consequence of several cardiorespiratory illnesses. Measuring the retinal microvasculature at high altitude provides a surrogate for cerebral microvasculature, offering potential insight into cerebral hypoxia in critical illness. In addition, although sex-specific differences in cardiovascular diseases are strongly supported, few have focused on differences in ocular blood flow. We evaluated the retinal microvasculature in males (n = 11) and females (n = 7) using functional optical coherence tomography at baseline (1,130 m) (day 0), following rapid ascent (day 2), and prolonged exposure (day 9) to high altitude (3,800 m). Retinal vascular perfusion density (rVPD; an index of total blood supply), retinal thickness (RT; reflecting vascular and neural tissue volume), and arterial blood were acquired. As a group, rVPD increased on day 2 versus day 0 (P < 0.001) and was inversely related to PaO2 (R2 = 0.45; P = 0.006). By day 9, rVPD recovered to baseline but was significantly lower in males than in females (P = 0.007). RT was not different on day 2 versus day 0 (P > 0.99) but was reduced by day 9 relative to day 0 and day 2 (P < 0.001). RT changes relative to day 0 were inversely related to changes in PaO2 on day 2 (R2 = 0.6; P = 0.001) and day 9 (R2 = 0.4; P = 0.02). RT did not differ between sexes. These data suggest differential time course and regulation of the retina during rapid ascent and prolonged exposure to high altitude and are the first to demonstrate sex-specific differences in rVPD at high altitude. The ability to assess intact microvasculature contiguous with the brain has widespread research and clinical applications.
AB - Cerebral hypoxia is a serious consequence of several cardiorespiratory illnesses. Measuring the retinal microvasculature at high altitude provides a surrogate for cerebral microvasculature, offering potential insight into cerebral hypoxia in critical illness. In addition, although sex-specific differences in cardiovascular diseases are strongly supported, few have focused on differences in ocular blood flow. We evaluated the retinal microvasculature in males (n = 11) and females (n = 7) using functional optical coherence tomography at baseline (1,130 m) (day 0), following rapid ascent (day 2), and prolonged exposure (day 9) to high altitude (3,800 m). Retinal vascular perfusion density (rVPD; an index of total blood supply), retinal thickness (RT; reflecting vascular and neural tissue volume), and arterial blood were acquired. As a group, rVPD increased on day 2 versus day 0 (P < 0.001) and was inversely related to PaO2 (R2 = 0.45; P = 0.006). By day 9, rVPD recovered to baseline but was significantly lower in males than in females (P = 0.007). RT was not different on day 2 versus day 0 (P > 0.99) but was reduced by day 9 relative to day 0 and day 2 (P < 0.001). RT changes relative to day 0 were inversely related to changes in PaO2 on day 2 (R2 = 0.6; P = 0.001) and day 9 (R2 = 0.4; P = 0.02). RT did not differ between sexes. These data suggest differential time course and regulation of the retina during rapid ascent and prolonged exposure to high altitude and are the first to demonstrate sex-specific differences in rVPD at high altitude. The ability to assess intact microvasculature contiguous with the brain has widespread research and clinical applications.
KW - cerebral microvasculature
KW - functional optical coherence tomography
KW - high altitude
KW - hypoxia
KW - retinal microvasculature
UR - http://www.scopus.com/inward/record.url?scp=85137125313&partnerID=8YFLogxK
U2 - 10.1152/japplphysiol.00132.2022
DO - 10.1152/japplphysiol.00132.2022
M3 - Article
C2 - 35771223
AN - SCOPUS:85137125313
SN - 8750-7587
VL - 133
SP - 534
EP - 545
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 3
ER -