title: A pseudo-three-dimensional model for quantification of oxygen diffusion from preglomerular arteries to renal tissue and renal venous blood.
abstract: 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 (~0.9% of total renal oxygen delivery; range 0.4-1.4%), but increases during renal ischemia, glomerular hyperfiltration (~2.1% of total renal oxygen delivery; range 0.84-3.36%), and some cardiovascular disease states (~3.0% of total renal oxygen delivery; range 1.2-4.8%). Under normal physiological conditions, blood Po2is predicted to fall by ~16 mmHg from the root of the renal artery to glomerular entry, with AV oxygen shunting contributing ~40% and oxygen diffusion from arteries to tissue contributing ~60% of this decline. Arterial Po2is predicted to fall most rapidly from Strahlerorder 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.
authors.affiliation: Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Chang-Joon
authors.initials: CJ
authors.lastname: Lee
authors.affiliation: Cardiovascular Disease Program, Biosciences Discovery Institute and Department of Physiology, Monash University, Melbourne, Sydney, Australia; and.
authors.forename: Jennifer P
authors.initials: JP
authors.lastname: Ngo
authors.affiliation: Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Saptarshi
authors.identifier: http://orcid.org/0000-0002-3788-372X
authors.initials: S
authors.lastname: Kar
authors.affiliation: School of Engineering and Information Technology, Murdoch University, Perth, Western Australia, Australia.
authors.forename: Bruce S
authors.initials: BS
authors.lastname: Gardiner
authors.affiliation: Cardiovascular Disease Program, Biosciences Discovery Institute and Department of Physiology, Monash University, Melbourne, Sydney, Australia; and.
authors.forename: Roger G
authors.identifier: http://orcid.org/0000-0002-9241-0757
authors.initials: RG
authors.lastname: Evans
authors.affiliation: Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia; david.smith@uwa.edu.au.
authors.forename: David W
authors.initials: DW
authors.lastname: Smith
mesh_terms: D000818:Animals; D002318:Cardiovascular Diseases / Q000097:blood / Q000503:physiopathology; D015687:Cell Hypoxia; D003198:Computer Simulation; D004058:Diffusion; D005919:Glomerular Filtration Rate; D007511:Ischemia / Q000097:blood / Q000503:physiopathology; D007668:Kidney / Q000098:blood supply* / Q000378:metabolism*; D008955:Models, Cardiovascular; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D051381:Rats; D012077:Renal Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D012079:Renal Circulation; D012082:Renal Veins / Q000000981:diagnostic imaging / Q000502:physiology*; D015203:Reproducibility of Results; D055114:X-Ray Microtomography
chemical_list: D010100:Oxygen
keywords: arterial-to-venous oxygen shunting; computational model; renal oxygenation