TY - JOUR

T1 - Corticomedullary shunting after ischaemia and reperfusion in the porcine kidney?

AU - Rehling, Michael

AU - Skjøth, Stine Gram

AU - Frøkiær, Jørgen

AU - Nielsen, Lene Elsebeth

AU - Flø, Christian

AU - Jespersen, Bente

AU - Keller, Anna Krarup

N1 - Publisher Copyright: © 2022, The Author(s).

PY - 2022

Y1 - 2022

N2 - Background: Renal perfusion may redistribute from cortex to medulla during systemic hypovolaemia and after renal ischaemia for other reasons, but there is no consensus on this matter. We studied renal perfusion after renal ischaemia and reperfusion. Methods: Renal perfusion distribution was examined by use of 153Gadolinium-labeled microspheres (MS) after 2 h (hrs) and 4 h ischaemia of the pig kidney followed by 4 h of reperfusion. Intra-arterial injected MS are trapped in the glomeruli in renal cortex, which means that MS are not present in the medulla under normal physiological conditions. Results: Visual evaluation after reperfusion demonstrated that MS redistributed from the renal cortex to the medulla in 6 out of 16 pigs (38%) subjected to 4 h ischaemia and in one out of 18 pigs subjected to 2 h ischaemia. Central renal uptake of MS covering the medullary/total renal uptake was significantly higher in kidneys subjected to 4 h ischaemia compared with pigs subjected to 2 h ischaemia (69 ± 5% vs. 63 ± 1%, p < 0.001), and also significantly higher than in the contralateral kidney (69 ± 5% vs. 63 ± 2%, p < 0.001). Analysis of blood and urine demonstrated no presence of radioactivity. Conclusion: The study demonstrated the presence of MS in the renal medulla in response to renal ischaemia and reperfusion suggesting that severe ischaemia and reperfusion of the pig kidney leads to opening of functional shunts bypassing glomeruli.

AB - Background: Renal perfusion may redistribute from cortex to medulla during systemic hypovolaemia and after renal ischaemia for other reasons, but there is no consensus on this matter. We studied renal perfusion after renal ischaemia and reperfusion. Methods: Renal perfusion distribution was examined by use of 153Gadolinium-labeled microspheres (MS) after 2 h (hrs) and 4 h ischaemia of the pig kidney followed by 4 h of reperfusion. Intra-arterial injected MS are trapped in the glomeruli in renal cortex, which means that MS are not present in the medulla under normal physiological conditions. Results: Visual evaluation after reperfusion demonstrated that MS redistributed from the renal cortex to the medulla in 6 out of 16 pigs (38%) subjected to 4 h ischaemia and in one out of 18 pigs subjected to 2 h ischaemia. Central renal uptake of MS covering the medullary/total renal uptake was significantly higher in kidneys subjected to 4 h ischaemia compared with pigs subjected to 2 h ischaemia (69 ± 5% vs. 63 ± 1%, p < 0.001), and also significantly higher than in the contralateral kidney (69 ± 5% vs. 63 ± 2%, p < 0.001). Analysis of blood and urine demonstrated no presence of radioactivity. Conclusion: The study demonstrated the presence of MS in the renal medulla in response to renal ischaemia and reperfusion suggesting that severe ischaemia and reperfusion of the pig kidney leads to opening of functional shunts bypassing glomeruli.

KW - Microspheres

KW - Renal blood flow

KW - Renal ischaemia

KW - Renal perfusion

KW - Renal redistribution

KW - Renal shunts

UR - http://www.scopus.com/inward/record.url?scp=85128415211&partnerID=8YFLogxK

U2 - 10.1186/s12882-022-02780-0

DO - 10.1186/s12882-022-02780-0

M3 - Journal article

C2 - 35428270

AN - SCOPUS:85128415211

VL - 23

JO - B M C Nephrology

JF - B M C Nephrology

SN - 1471-2369

IS - 1

M1 - 146

ER -