Determinants of renal tissue oxygenation as measured with BOLD-MRI in chronic kidney disease and hypertension in humans

PLoS One. 2014 Apr 23;9(4):e95895. doi: 10.1371/journal.pone.0095895. eCollection 2014.

Abstract

Experimentally renal tissue hypoxia appears to play an important role in the pathogenesis of chronic kidney disease (CKD) and arterial hypertension (AHT). In this study we measured renal tissue oxygenation and its determinants in humans using blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) under standardized hydration conditions. Four coronal slices were selected, and a multi gradient echo sequence was used to acquire T2* weighted images. The mean cortical and medullary R2* values ( = 1/T2*) were calculated before and after administration of IV furosemide, a low R2* indicating a high tissue oxygenation. We studied 195 subjects (95 CKD, 58 treated AHT, and 42 healthy controls). Mean cortical R2 and medullary R2* were not significantly different between the groups at baseline. In stimulated conditions (furosemide injection), the decrease in R2* was significantly blunted in patients with CKD and AHT. In multivariate linear regression analyses, neither cortical nor medullary R2* were associated with eGFR or blood pressure, but cortical R2* correlated positively with male gender, blood glucose and uric acid levels. In conclusion, our data show that kidney oxygenation is tightly regulated in CKD and hypertensive patients at rest. However, the metabolic response to acute changes in sodium transport is altered in CKD and in AHT, despite preserved renal function in the latter group. This suggests the presence of early renal metabolic alterations in hypertension. The correlations between cortical R2* values, male gender, glycemia and uric acid levels suggest that these factors interfere with the regulation of renal tissue oxygenation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Intravenous
  • Adult
  • Aged
  • Case-Control Studies
  • Cell Hypoxia
  • Diuretics / administration & dosage
  • Female
  • Furosemide / administration & dosage
  • Humans
  • Hypertension / metabolism*
  • Hypertension / pathology
  • Kidney / anatomy & histology
  • Kidney / drug effects
  • Kidney / metabolism
  • Kidney Cortex / drug effects
  • Kidney Cortex / metabolism*
  • Kidney Medulla / drug effects
  • Kidney Medulla / metabolism*
  • Magnetic Resonance Imaging / methods*
  • Male
  • Middle Aged
  • Oxygen / blood*
  • Oxygen Consumption
  • Renal Insufficiency, Chronic / metabolism*
  • Renal Insufficiency, Chronic / pathology

Substances

  • Diuretics
  • Furosemide
  • Oxygen

Grant support

This study was supported by research grants from the Swiss National Science Foundation (FN 32003B-132913 and 149309) and by the Centre d'Imagerie BioMédicale (CIBM) of the University of Lausanne (UNIL). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.