Abstract
Tissue hypoxia has been demonstrated, in both the renal cortex and medulla, during the acute phase of reperfusion after ischemia induced by occlusion of the aorta upstream from the kidney. However, there are also recent clinical observations indicating relatively well preserved oxygenation in the nonfunctional transplanted kidney. To test whether severe acute kidney injury can occur in the absence of widespread renal tissue hypoxia, we measured cortical and inner medullary tissue PO2 as well as total renal O2 delivery (DO2) and O2 consumption (V ̇O2) during the first 2 h of reperfusion after 60 min of occlusion of the renal artery in anesthetized rats. To perform this experiment, we used a new method for measuring kidney DO2 andV ̇O2 that relies on implantation of fluorescence optodes in the femoral artery and renal vein. We were unable to detect reductions in renal cortical or inner medullary tissue PO2 during reperfusion after ischemia localized to the kidney. This is likely explained by the observation thatV ̇O2 (-57%) was reduced by at least as much as DO2 (-45%), due to a large reduction in glomerular filtration (-94%). However, localized tissue hypoxia, as evidence by pimonidazole adduct immunohistochemistry, was detected in kidneys subjected to ischemia and reperfusion, particularly in, but not exclusive to, the outer medulla. Thus, cellular hypoxia, particularly in the outer medulla, may still be present during reperfusion even when reductions in tissue PO2 are not detected in the cortex or inner medulla.
| Original language | English |
|---|---|
| Journal | American Journal of Physiology - Renal Physiology |
| Volume | 306 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - 1 May 2014 |
| Externally published | Yes |
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Renal oxygenation in acute renal ischemia-reperfusion injury. / Abdelkader, Amany; Ho, Julie; Ow, Connie P.C.; Eppel, Gabriela A.; Rajapakse, Niwanthi W.; Schlaich, Markus P.; Evans, Roger G.
In: American Journal of Physiology - Renal Physiology, Vol. 306, No. 9, 01.05.2014.Research output: Contribution to journal › Article
TY - JOUR
T1 - Renal oxygenation in acute renal ischemia-reperfusion injury
AU - Abdelkader, Amany
AU - Ho, Julie
AU - Ow, Connie P.C.
AU - Eppel, Gabriela A.
AU - Rajapakse, Niwanthi W.
AU - Schlaich, Markus P.
AU - Evans, Roger G.
PY - 2014/5/1
Y1 - 2014/5/1
N2 - Tissue hypoxia has been demonstrated, in both the renal cortex and medulla, during the acute phase of reperfusion after ischemia induced by occlusion of the aorta upstream from the kidney. However, there are also recent clinical observations indicating relatively well preserved oxygenation in the nonfunctional transplanted kidney. To test whether severe acute kidney injury can occur in the absence of widespread renal tissue hypoxia, we measured cortical and inner medullary tissue PO2 as well as total renal O2 delivery (DO2) and O2 consumption (V ̇O2) during the first 2 h of reperfusion after 60 min of occlusion of the renal artery in anesthetized rats. To perform this experiment, we used a new method for measuring kidney DO2 andV ̇O2 that relies on implantation of fluorescence optodes in the femoral artery and renal vein. We were unable to detect reductions in renal cortical or inner medullary tissue PO2 during reperfusion after ischemia localized to the kidney. This is likely explained by the observation thatV ̇O2 (-57%) was reduced by at least as much as DO2 (-45%), due to a large reduction in glomerular filtration (-94%). However, localized tissue hypoxia, as evidence by pimonidazole adduct immunohistochemistry, was detected in kidneys subjected to ischemia and reperfusion, particularly in, but not exclusive to, the outer medulla. Thus, cellular hypoxia, particularly in the outer medulla, may still be present during reperfusion even when reductions in tissue PO2 are not detected in the cortex or inner medulla.
AB - Tissue hypoxia has been demonstrated, in both the renal cortex and medulla, during the acute phase of reperfusion after ischemia induced by occlusion of the aorta upstream from the kidney. However, there are also recent clinical observations indicating relatively well preserved oxygenation in the nonfunctional transplanted kidney. To test whether severe acute kidney injury can occur in the absence of widespread renal tissue hypoxia, we measured cortical and inner medullary tissue PO2 as well as total renal O2 delivery (DO2) and O2 consumption (V ̇O2) during the first 2 h of reperfusion after 60 min of occlusion of the renal artery in anesthetized rats. To perform this experiment, we used a new method for measuring kidney DO2 andV ̇O2 that relies on implantation of fluorescence optodes in the femoral artery and renal vein. We were unable to detect reductions in renal cortical or inner medullary tissue PO2 during reperfusion after ischemia localized to the kidney. This is likely explained by the observation thatV ̇O2 (-57%) was reduced by at least as much as DO2 (-45%), due to a large reduction in glomerular filtration (-94%). However, localized tissue hypoxia, as evidence by pimonidazole adduct immunohistochemistry, was detected in kidneys subjected to ischemia and reperfusion, particularly in, but not exclusive to, the outer medulla. Thus, cellular hypoxia, particularly in the outer medulla, may still be present during reperfusion even when reductions in tissue PO2 are not detected in the cortex or inner medulla.
KW - Hypoxia
KW - Ischemia-reperfusion injury
KW - Renal oxygen consumption
KW - Renal oxygen delivery
UR - http://www.scopus.com/inward/record.url?scp=84900525558&partnerID=8YFLogxK
U2 - 10.1152/ajprenal.00281.2013
DO - 10.1152/ajprenal.00281.2013
M3 - Article
VL - 306
JO - American journal of physiology : renal physiology
JF - American journal of physiology : renal physiology
SN - 1522-1466
IS - 9
ER -