Renal blood flow and oxygenation

Abstract

Our kidneys receive about one-fifth of the cardiac output at rest and have a low oxygen extraction ratio, but may sustain, under some conditions, hypoxic injuries that might lead to chronic kidney disease. This is due to large regional variations in renal blood flow and oxygenation, which are the prerequisite for some and the consequence of other kidney functions. The concurrent operation of these functions is reliant on a multitude of neuro-hormonal signaling cascades and feedback loops that also include the regulation of renal blood flow and tissue oxygenation. Starting with open questions on regulatory processes and disease mechanisms, we review herein the literature on renal blood flow and oxygenation. We assess the current understanding of renal blood flow regulation, reasons for disparities in oxygen delivery and consumption, and the consequences of disbalance between O2 delivery, consumption, and removal. We further consider methods for measuring and computing blood velocity, flow rate, oxygen partial pressure, and related parameters and point out how limitations of these methods constitute important hurdles in this area of research. We conclude that to obtain an integrated understanding of the relation between renal function and renal blood flow and oxygenation, combined experimental and computational modeling studies will be needed.

Is serum hemoglobin level an independent prognostic factor for IgA nephropathy?: a systematic review and meta-analysis of observational cohort studies

“…Since the shunt and diffusion of oxygen between venous and arterial vessels that run in close parallel contact, the oxygen tensions of renal tissue are in fact comparatively low. Thus, the kidneys are sensitive to changes in systemic oxygenation [ 32 ]. Anemia might accelerate renal function decline by inducing tubulointerstitial hypoxia [ 33 ].…”

Hybrid photoacoustic and fast super-resolution ultrasound imaging

“…6a, b). It has been shown that renal blood flow velocity correlates to renal tissue oxygenation 62,63 . To showcase the capability of the interleaved PA/SC-ULM imaging, we conducted an in vivo oxygen-challenge experiment in mice to mimic various scenarios of tissue oxygenation and image the corresponding blood velocity change.…”

Evaluation of a deuterated triarylmethyl spin probe for in vivo R2∗‐based EPR oximetric imaging with enhanced dynamic range

“…Normal organs also may have a wide range of pO 2 distribution. The pO 2 in renal cortical tissue falls within the range of 20 to 60 mm Hg, whereas the pO 2 values in the outer and inner medulla are in the range of 15 to 30 mm Hg and <15 mm Hg, respectively 19,20 . BOLD‐MRI has been used to detect R 2 value changes in the cortex and medulla 21 .…”