科研之友
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摘要
To assess the physiological significance of arterial-to-venous (AV) oxygen shunting, we generated a new pseudo-three-dimensional computational model of oxygen diffusion from intrarenal arteries to cortical tissue and veins. The model combines the 11 branching levels (known as "Strahler" orders) of the preglomerular renal vasculature in the rat, with an analysis of an extensive data set obtained using light microscopy to estimate oxygen mass transfer coefficients for each Strahler order. Furthermore, the AV shunting model is now set within a global oxygen transport model that includes transport from arteries, glomeruli, peritubular capillaries, and veins to tissue. While a number of lines of evidence suggest AV shunting is significant, most importantly, our AV oxygen shunting model predicts AV shunting is small under normal physiological conditions (similar to 0.9% of total renal oxygen delivery; range 0.4-1.4%), but increases during renal ischemia, glomerular hyperfiltration (similar to 2.1% of total renal oxygen delivery; range 0.84-3.36%), and some cardiovascular disease states (similar to 3.0% of total renal oxygen delivery; range 1.2-4.8%). Under normal physiological conditions, blood PO2 is predicted to fall by similar to 16 mmHg from the root of the renal artery to glomerular entry, with AV oxygen shunting contributing similar to 40% and oxygen diffusion from arteries to tissue contributing similar to 60% of this decline. Arterial PO2 is predicted to fall most rapidly from Strahler order 4, under normal physiological conditions. We conclude that AV oxygen shunting normally has only a small impact on renal oxygenation, but may exacerbate renal hypoxia during renal ischemia, hyperfiltration, and some cardiovascular disease states.
- 出版日期2017-8
