Changes in renal medullary pO2 during water diuresis as evaluated by blood oxygenation level–dependent magnetic resonance imaging: Effects of aging and cyclooxygenase inhibition

摘要

BackgroundHypoxia of the renal medulla has been implicated in the development of renal injury, particularly acute renal failure, and its regulation in humans may therefore be relevant to certain renal disorders. Changes in oxygenation of the renal medulla can now be monitored noninvasively with blood oxygenation level–dependent (BOLD) magnetic resonance imaging (MRI). Using this method, water diuresis has been shown to improve medullary oxygenation in young persons. Urinary excretion of prostaglandin E2 (PGE2) likewise increases during water diuresis in younger but not in older people. We used BOLD MRI to measure the effects of aging and of inhibiting prostaglandin synthetase on the renal response to water diuresis in healthy human subjects.