Global REACH 2018: Renal oxygen delivery is maintained during early acclimatization to 4330 m

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  • Andrew R Steele
    University of Alberta
  • Michael M Tymko
    University of Alberta
  • Victoria L Meah
    University of Alberta
  • Lydia Simpson
  • Chris Gasho
    Loma Linda University
  • Tony G Dawkins
    Cardiff Metropolitan University
  • Francisco C Villafuerte
    Universidad Peruana Cayetano Heredia
  • Philip N Ainslie
    University of British Columbia
  • Michael Stembridge
    Cardiff Metropolitan University
  • Jonathan Moore
  • Craig D Steinback
    University of Alberta
Early acclimatization to high-altitude is characterized by various respiratory, hematological, and cardiovascular adaptations that serve to restore oxygen delivery to tissue. However, less is understood about renal function and the role of renal oxygen delivery (RDO2) during high-altitude acclimatization. We hypothesized that: 1) RDO2 would be reduced after 12-hours of high-altitude exposure (high-altitude day1) but restored to sea-level values after one-week (high-altitude day7); and 2) RDO2 would be associated with renal reactivity (RR), an index of acid-base compensation at high-altitude. Twenty-four healthy lowlander participants were tested at sea-level (344m; Kelowna, Canada), on day1 and day7 at high-altitude (4330m; Cerro de Pasco, Peru). Cardiac output, renal blood flow, arterial and venous blood sampling for renin-angiotensin-aldosterone-system hormones and NT pro-B type natriuretic peptides were collected at each time point. RR was calculated as: (Δ arterial bicarbonate)/(Δ partial pressure of arterial carbon dioxide) between sea-level and high-altitude day1, and sea-level and high-altitude day7. The main findings were: 1) RDO2 was initially decreased at high-altitude compared to sea-level (ΔRDO2: -22±17%, P<0.001), but was restored to sea-level values on high-altitude day7 (ΔRDO2: -6±14%, P=0.36). The observed improvements in RDO2 resulted from both changes in renal blood flow (Δ from high-altitude day1: +12±11%; P=0.008), and arterial oxygen content (Δ from high-altitude day1 +44.8±17.7%; P=0.006); and 2) RR was positively correlated with RDO2 on high-altitude day7 (r=0.70; P<0.001), but not high-altitude day1 (r=0.26; P=0.29). These findings characterize the temporal responses of renal function during early high-altitude acclimatization, and the influence of RDO2 in the regulation of acid-base.
Original languageEnglish
Pages (from-to)F1081-F1089
JournalAmerican Journal of Physiology: Renal Physiology
Volume319
Issue number6
Early online date30 Sept 2020
DOIs
Publication statusPublished - 1 Dec 2020

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