26. Nanoparticle release by Extended Criteria Donor kidneys during normothermic machine perfusion

W.W. Woud, A. Merino, M. Hoogduijn, K. Boer, M.W.F. van den Hoogen, C.C. Baan, R.C. Minnee

Thursday 5 march 2020

0:00 - 0:00h at Toon Hermans Foyer

Parallel session: Postersessie 6 – Basale abstracts

Background: Extended criteria donor (ECD) organs suffer from more injury due to more severe ischemia/reperfusion injuries and other donor morbidities compared to standard criteria donors. Therefore, new methods of organ preservation and assessment are needed. Machine perfusion (MP) has extensively been studied and allows for the ex vivo examination of kidneys through analysis of perfusion fluids. We postulate that analysis of kidney derived nanoparticles, including Extracellular Vesicles (EVs), in perfusion fluid during normothermic MP may allow for the assessment of kidney quality prior to transplantation.

Methods: ECD kidneys were perfused at 37 ^oC for 2h during which perfusate samples were taken at 30 min intervals. Samples were centrifuged at 16.000g for 10 min to discard cellular debris, diluted 10x in 0.22 µm filtered PBS and analysed by Nanoparticle Tracking Analysis (NTA) to determine nanoparticle size and concentration.

Results: Perfusates from three ECD kidneys (2 donors after cardiac death, 1 donor after brain death, comparable warm ischemia times of 15 minutes followed by 12 hours of cold ischemia, age 66/73/65, all male) were analysed. Although two size populations (120 & 170 nm) were observed in the perfusate after 2h of perfusion, the average particle size was found to remain unchanged (~155 ± 7.6 nm) during the entire perfusion procedure. An ~7.75-fold increase in cumulative nanoparticle concentration was observed over time: 9.03E⁹ particles/mL after 2h compared to 1.17E⁹ particles/mL after 0 min of perfusion. Particle excretion increased in a linear manner.

Conclusions: These results indicate that analysis of perfusion fluid by NTA may be utilized to assess renal quality prior to transplantation. The released nanoparticles are likely to contain kidney-derived EVs which may be indicative for renal quality. Nevertheless, whether this release of nanoparticles reflects kidney function requires further research.