"Since 1996, BOLD-MRI has been used in humans to evaluate, amongst others, the effect of water diuresis on renal medulla and cortex in healthy volunteers [34, 35] and diabetic patients  and to monitor changes in renal oxygenation after administration of different drugs [36, 37] and after acute renal ischemia [38, 39]. "
[Show abstract][Hide abstract] ABSTRACT: Animal studies suggest that renal tissue hypoxia plays an important role in the development of renal damage in hypertension and renal diseases, yet human data were scarce due to the lack of noninvasive methods. Over the last decade, blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI), detecting deoxyhemoglobin in hypoxic renal tissue, has become a powerful tool to assess kidney oxygenation noninvasively in humans. This paper provides an overview of BOLD-MRI studies performed in patients suffering from essential hypertension or chronic kidney disease (CKD). In line with animal studies, acute changes in cortical and medullary oxygenation have been observed after the administration of medication (furosemide, blockers of the renin-angiotensin system) or alterations in sodium intake in these patient groups, underlining the important role of renal sodium handling in kidney oxygenation. In contrast, no BOLD-MRI studies have convincingly demonstrated that renal oxygenation is chronically reduced in essential hypertension or in CKD or chronically altered after long-term medication intake. More studies are required to clarify this discrepancy and to further unravel the role of renal oxygenation in the development and progression of essential hypertension and CKD in humans.
International Journal of Hypertension 02/2013; 2013:696598. DOI:10.1155/2013/696598
"Various stimuli were used to study the regulation of renal perfusion and oxygenation in animals under physiological conditions. For this purpose, vasoactive agents like nitric oxide (Li et al. 2003, 2009), prostaglandins (Prasad et al. 2001), reductions in RPP (Juillard et al. 2004, Alford et al. 2005), water diuresis (Prasad & Epstein 1999, Epstein et al. 2002, Haque et al. 2011) and changes in inspiratory oxygen fraction (Pedersen et al. 2005) were used to modify renal perfusion and oxygen delivery. To lower renal oxygen consumption, diuretics that reduce tubular reabsorption were applied (Li et al. 2004, Gomez et al. 2009, Warner et al. 2011). "
[Show abstract][Hide abstract] ABSTRACT: Presence of renal hypoxia and its consequences to renal pathophysiology is well accepted now. Most data on renal oxygenation
available today are based on animal models, and an ability to translate the findings to humans was highly desired. Although,
several novel methodologies are being pursued, to date blood oxygenation level dependent (BOLD) magnetic resonance imaging
(MRI) is the only known technique available to evaluate renal oxygenation in humans. The technique is noninvasive, based on
an endogenous contrast mechanism, and can be applied to both animal models and humans. The ability to evaluate relative renal
oxygenation status in both health and disease could be useful in better understanding the pathophysiology and allowing for
monitoring of potential novel interventions.
In this chapter, we provide an overview of the principles involved and the implementation and various applications that investigators
around the world have pursued to date.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.