HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 296/1/R67    most recent 90677.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Warner, L. Articles by Romero, J. C. Search for Related Content PubMed PubMed Citation Articles by Warner, L. Articles by Romero, J. C.

HEMODYNAMICS AND CARDIORENAL INTEGRATION

Regional decreases in renal oxygenation during graded acute renal arterial stenosis: a case for renal ischemia

¹Department of Physiology and Biomedical Engineering and the ²Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota; and ³Department of Biological Sciences, Minnesota State University, Mankato, Minnesota

Submitted 11 August 2008 ; accepted in final form 24 October 2008

Ischemic nephropathy describes progressive renal failure, defined by significantly reduced glomerular filtration rate, and may be due to renal artery stenosis (RAS), a narrowing of the renal artery. It is unclear whether ischemia is present during RAS since a decrease in renal blood flow (RBF), O₂ delivery, and O₂ consumption occurs. The present study tests the hypothesis that despite proportional changes in whole kidney O₂ delivery and consumption, acute progressive RAS leads to decreases in regional renal tissue O₂. Unilateral acute RAS was induced in eight pigs with an extravascular cuff. RBF was measured with an ultrasound flow probe. Cortical and medullary tissue oxygen of the stenotic kidney was measured continuously with sensors during baseline, three sequentially graded decreases in RBF, and recovery. O₂ consumption decreased proportionally to O₂ delivery during the graded stenosis (19 ± 10.8, 48.2 ± 9.1, 58.9 ± 4.7 vs. 15.1 ± 5, 35.4 ± 3.5, 57 ± 2.3%, respectively) while arterial venous O₂ differences were unchanged. Acute RAS produced a sharp reduction in O₂ efficiency for sodium reabsorption (P < 0.01). Cortical decreases are exceeded by medullary decreases during stenosis (34.8 ± 1.3%). Decreases in tissue oxygenation, more pronounced in the medulla than the cortex, occur despite proportional reductions in O₂ delivery and consumption. This demonstrates for the first time that hypoxia is present in the early stages of RAS and suggests a role for hypoxia in the pathophysiology of this disease. Furthermore, the notion that arteriovenous shunting and increased stoichiometric energy requirements are potential contributors toward ensuing hypoxia with graded and progressive acute RAS cannot be excluded.

ischemia; renal tissue oxygenation; renal blood flow; pig

This article has been cited by other articles:

				S. I. Gomez, L. Warner, J. A. Haas, R. J. Bolterman, S. C. Textor, L. O. Lerman, and J. C. Romero Increased hypoxia and reduced renal tubular response to furosemide detected by BOLD magnetic resonance imaging in swine renovascular hypertension Am J Physiol Renal Physiol, October 1, 2009; 297(4): F981 - F986. [Abstract] [Full Text] [PDF]