Evolution of renal oxygen content measured by BOLD MRI downstream a chronic renal artery stenosis

• Published in: Nephrology, dialysis, transplantation dialysis, transplantation, 2011-04, Vol.26 (4), p.1205-1210
• Main Authors: ROGNANT, Nicolas, GUEBRE-EGZIABHER, Fitsum, BACCHETTA, Justine, JANIER, Marc, HIBA, Bassem, LANGLOIS, Jean Baptiste, GADET, Rudy, LAVILLE, Maurice, JUILLARD, Laurent
• Format: Article
• Language: English
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Biological and medical sciences; Chronic Disease; Diuretics - administration & dosage; Emergency and intensive care: renal failure. Dialysis management; Furosemide - administration & dosage; Hypoxia - drug therapy; Hypoxia - etiology; Intensive care medicine; Magnetic Resonance Imaging; Male; Medical sciences; Nephrology. Urinary tract diseases; Nephropathies. Renovascular diseases. Renal failure; Oxygen - metabolism; Oxygen Consumption; Rats; Rats, Sprague-Dawley; Renal Artery - physiopathology; Renal Artery Obstruction - complications; Renal failure
• ISSN: 0931-0509; 1460-2385
• DOI: 10.1093/ndt/gfq538

A decrease in renal oxygen content can be measured non-invasively by the increase of the R2* value derived from blood oxygen level-dependent magnetic resonance imaging (BOLD MRI). The aim of this study was to test if renal hypoxia occurs in kidneys downstream a chronic and unilateral renal artery stenosis. Chronic renal ischaemia was induced in rats using a calibrated clip inserted on the right renal artery. R2* was determined, using a multiple recalled gradient-echo sequence, before and once a week after a clip insertion over 4 weeks, in a group of clipped (n = 8) and sham-operated (n = 7) rats. At baseline, in stenotic kidneys, R2* was higher in the outer stripe of outer medulla (105 ± 4.6) and the outer medulla (99 ± 2.5) than in the cortex (84 ± 2.5; P < 0.002 for comparison with both areas). R2* was unchanged in the cortex, the outer stripe of outer medulla and the outer medulla in stenotic kidneys, sham-operated kidneys and contralateral kidneys during the 4 weeks. Mean blood pressure was higher in rats with clipped kidney than in sham-operated rats from Day 11 and remained increased thereafter. The renal volume increased progressively in sham-operated kidneys and contralateral kidneys, whereas it slightly decreased in stenotic kidneys. Our study shows that after 4 weeks, no renal hypoxia can be detected in the kidney downstream to a renal artery stenosis, suggesting that atrophy could be induced by other factors.