Renal cortex microperfusion evaluated by laser speckle contrast imaging in an ex vivo perfused kidney model—A proof-of-concept study

TY - JOUR

T1 - Renal cortex microperfusion evaluated by laser speckle contrast imaging in an ex vivo perfused kidney model—A proof-of-concept study

AU - Arildsen, Maibritt Meldgård

AU - Thrane, Lars

AU - Staulund, Jesper

AU - Eijken, Marco

AU - Jespersen, Bente

AU - Postnov, Dmitry

AU - Al-Mashhadi, Rozh

AU - Pedersen, Michael

PY - 2024/4

Y1 - 2024/4

N2 - Background: Validated quantitative biomarkers for assessment of renal graft function during normothermic machine perfusion (NMP) conditions are lacking. The aim of this project was to quantify cortex microperfusion during ex vivo kidney perfusion using laser speckle contrast imaging (LSCI), and to evaluate the sensitivity of LSCI when measuring different levels of renal perfusion. Furthermore, we aimed to introduce LSCI measurements during NMP in differentially damaged kidneys. Methods: Eleven porcine kidneys were nephrectomized and perfused ex vivo. Cortex microperfusion was simultaneously monitored using LSCI. First, a flow experiment examined the relationship between changes in delivered renal flow and corresponding changes in LSCI-derived cortex microperfusion. Second, renal cortical perfusion was reduced stepwise by introducing a microembolization model. Finally, LSCI was applied for measuring renal cortex microperfusion in kidneys exposed to minimal damage or 2 h warm ischemia (WI). Results: Cortex microperfusion was calculated from the LSCI-obtained data. The flow experiment resulted in relatively minor changes in cortex microperfusion compared to the pump-induced changes in total renal flow. Based on stepwise injections of microspheres, we observed different levels of cortex microperfusion that correlated with administrated microsphere dosages (r 2 = 0.95–0.99). We found no difference in LSCI measured cortex microperfusion between the kidneys exposed to minimal damage (renal cortex blood flow index, rcBFI = 2090–2600) and 2 h WI (rcBFI = 2189–2540). Conclusions: Based on this preliminary study, we demonstrated the feasibility of LSCI in quantifying cortex microperfusion during ex vivo perfusion. Furthermore, based on LSCI-measurements, cortical microperfusion was similar in kidneys exposed to minimal and 2 h WI.

AB - Background: Validated quantitative biomarkers for assessment of renal graft function during normothermic machine perfusion (NMP) conditions are lacking. The aim of this project was to quantify cortex microperfusion during ex vivo kidney perfusion using laser speckle contrast imaging (LSCI), and to evaluate the sensitivity of LSCI when measuring different levels of renal perfusion. Furthermore, we aimed to introduce LSCI measurements during NMP in differentially damaged kidneys. Methods: Eleven porcine kidneys were nephrectomized and perfused ex vivo. Cortex microperfusion was simultaneously monitored using LSCI. First, a flow experiment examined the relationship between changes in delivered renal flow and corresponding changes in LSCI-derived cortex microperfusion. Second, renal cortical perfusion was reduced stepwise by introducing a microembolization model. Finally, LSCI was applied for measuring renal cortex microperfusion in kidneys exposed to minimal damage or 2 h warm ischemia (WI). Results: Cortex microperfusion was calculated from the LSCI-obtained data. The flow experiment resulted in relatively minor changes in cortex microperfusion compared to the pump-induced changes in total renal flow. Based on stepwise injections of microspheres, we observed different levels of cortex microperfusion that correlated with administrated microsphere dosages (r 2 = 0.95–0.99). We found no difference in LSCI measured cortex microperfusion between the kidneys exposed to minimal damage (renal cortex blood flow index, rcBFI = 2090–2600) and 2 h WI (rcBFI = 2189–2540). Conclusions: Based on this preliminary study, we demonstrated the feasibility of LSCI in quantifying cortex microperfusion during ex vivo perfusion. Furthermore, based on LSCI-measurements, cortical microperfusion was similar in kidneys exposed to minimal and 2 h WI.

KW - evaluation

KW - kidneys

KW - laser speckle contrast imaging

KW - porcine

KW - renal cortex microperfusion

UR - http://www.scopus.com/inward/record.url?scp=85176935660&partnerID=8YFLogxK

U2 - 10.1111/aor.14675

DO - 10.1111/aor.14675

M3 - Journal article

C2 - 37962102

SN - 0160-564X

VL - 48

SP - 347

EP - 355

JO - Artificial organs

JF - Artificial organs

IS - 4

ER -