Stein A, Goldmeier S, Voltolini S, Setogutti E, Feldman C, Figueiredo E, Eick R, Irigoyen M, Rigatto K. Renal oxygen content is increased in healthy subjects after angiotensin-converting enzyme inhibition.
Clinics (Sao Paulo) 2012;
67:761-5. [PMID:
22892920 PMCID:
PMC3400166 DOI:
10.6061/clinics/2012(07)10]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 03/20/2012] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE
The association between renal hypoxia and the development of renal injury is well established. However, no adequate method currently exists to non-invasively measure functional changes in renal oxygenation in normal and injured patients.
METHOD
R2* quantification was performed using renal blood oxygen level-dependent properties. Five healthy normotensive women (50 ± 5.3 years) underwent magnetic resonance imaging in a 1.5T Signa Excite HDx scanner (GE Healthcare, Waukesha, WI). A multiple fast gradient-echo sequence was used to acquire R2*/T2* images (sixteen echoes from 2.1 ms/slice to 49.6 ms/slice in a single breath hold per location). The images were post-processed to generate R2* maps for quantification. Data were recorded before and at 30 minutes after the oral administration of an angiotensin II-converting enzyme inhibitor (captopril, 25 mg). The results were compared using an ANOVA for repeated measurements (mean + standard deviation) followed by the Tukey test. ClinicalTrials.gov: NCT01545479.
RESULTS
A significant difference (p<0.001) in renal oxygenation (R2*) was observed in the cortex and medulla before and after captopril administration: right kidney, cortex = 11.08 ± 0.56 ms, medulla = 17.21 ± 1.47 ms and cortex = 10.30 ± 0.44 ms, medulla = 16.06 ± 1.74 ms, respectively; and left kidney, cortex= 11.79 ± 1.85 ms, medulla = 17.03 ± 0.88 ms and cortex = 10.89 ± 0.91 ms, medulla = 16.43 ± 1.49 ms, respectively.
CONCLUSIONS
This result suggests that the technique efficiently measured alterations in renal blood oxygenation after angiotensin II-converting enzyme inhibition and that it may provide a new strategy for identifying the early stages of renal disease and perhaps new therapeutic targets.
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