Factors that render the kidney susceptible to tissue hypoxia in hypoxemia

Roger G. Evans, Duncan Goddard, Gabriela A. Eppel, Paul M O'Connor

Research output: Contribution to journalArticle

34 Scopus citations

Abstract

To better understand what makes the kidney susceptible to tissue hypoxia, we compared, in the rabbit kidney and hindlimb, the ability of feedback mechanisms governing oxygen consumption (VO2) and oxygen delivery (DO2) to attenuate tissue hypoxia during hypoxemia. In the kidney (cortex and medulla) and hindlimb (biceps femoris muscle), we determined responses of whole organ blood flow and VO2, and local perfusion and tissue PO2, to reductions in DO2 mediated by graded systemic hypoxemia. Progressive hypoxemia reduced tissue PO2 similarly in the renal cortex, renal medulla, and biceps femoris. Falls in tissue PO2 could be detected when arterial oxygen content was reduced by as little as 4-8%.VO2 remained stable during progressive hypoxemia, only tending to fall once arterial oxygen content was reduced by 55% for the kidney or 42% for the hindlimb. Even then, the fall in renal VO2 could be accounted for by reduced oxygen demand for sodium transport rather than limited oxygen availability. Hindlimb blood flow and local biceps femoris perfusion increased progressively during graded hypoxia. In contrast, neither total renal blood flow nor cortical or medullary perfusion was altered by hypoxemia. Our data suggest that the absence in the kidney of hyperemic responses to hypoxia, and the insensitivity of renal VO2 to limited oxygen availability, contribute to kidney hypoxia during hypoxemia. The susceptibility of the kidney to tissue hypoxia, even in relatively mild hypoxemia, may have important implications for the progression of kidney disease, particularly in patients at high altitude or with chronic obstructive pulmonary disease.

Original languageEnglish (US)
Pages (from-to)R931-R940
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume300
Issue number4
DOIs
StatePublished - Apr 1 2011
Externally publishedYes

Keywords

  • Hyperemia
  • Hypoxia
  • Ischemia
  • Kidney circulation
  • Oxygen tension
  • Skeletal muscle

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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