Background.: Pancreas and islet transplantation outcomes are negatively impacted by injury to the endocrine cells from acute stress during donor death, organ procurement, processing, and transplant procedures. Here, we report a novel electron microscopy scoring system, the Newcastle Pancreas Endocrine Stress Score (NPESS). Methods.: NPESS was adapted and expanded from our previously validated method for scoring pancreatic exocrine acinar cells, yielding a 4-point scale (0–3) classifying ultrastructural pathology in endocrine cell nuclei, mitochondria, endoplasmic reticulum, cytoplasmic vacuolization, and secretory granule depletion, with a maximum additive score of 15. We applied NPESS in a cohort of deceased organ donors after brainstem (DBD) and circulatory (DCD) death with a wide range of cold ischemic times (3.6–35.9 h) including 3 donors with type 1 and 3 with type 2 diabetes to assess islets in situ (n = 30) in addition to pancreata (n = 3) pre- and postislet isolation. Results.: In DBD pancreata, NPESS correlated with cold ischemic time (head: r = 0.55; P = 0.02) and mirrored exocrine score (r = 0.48; P = 0.01). When stratified by endocrine phenotype, cells with granules of heterogeneous morphology had higher scores than α, β, and δ cells (P < 0.0001). Cells of mixed endocrine-exocrine morphology were observed in association with increased NPESS (P = 0.02). Islet isolation was associated with improved NPESS (in situ: 8.39 ± 0.77 [Mean ± SD]; postisolation: 5.44 ± 0.31; P = 0.04). Conclusions.: NPESS provides a robust method for semiquantitative scoring of subcellular ultrastructural changes in human pancreatic endocrine cells in situ and following islet isolation with utility for unbiased evaluation of acute stress in organ transplantation research.

Ex-vivo normothermic machine perfusion (NMP) of donor kidneys prior to transplantation provides a platform for direct delivery of cellular therapeutics to optimise organ quality prior to transplantation. Multipotent Adult Progenitor Cells (MAPC ^® ) possess potent immunomodulatory properties which could prove beneficial in minimising subsequent ischaemia reperfusion injury. We investigated the potential reconditioning capability of MAPC cells in kidney NMP. Methods: Pairs (5) of human kidneys from the same donor were simultaneously perfused for 7 hours. The right or left kidney was randomly allocated to receive MAPC treatment. Serial samples of perfusate, urine and tissue biopsies were taken for comparison with the control paired kidney. Results: MAPC-treated kidneys demonstrated improved urine output (p<0.01), decreased expression of the kidney injury biomarker NGAL (p<0.01), improved microvascular perfusion on contrast enhanced ultrasound (cortex p<0.05, medulla p<0.01), downregulation of IL-1β (p<0.05) and upregulation of IL-10 (p<0.05) and Indolamine-2, 3-dioxygenase (p<0.05). A mouse model of intraperitoneal chemotaxis demonstrated decreased neutrophil recruitment when stimulated with perfusate from MAPC-treated kidneys (p<0.01). Immunofluorescence revealed pre-labelled MAPC cells home to the perivascular space in the kidneys during NMP. MAPC therapy was not associated with detrimental physiological or embolic events. Conclusion: We report the first successful delivery of cellular therapy to a kidney during NMP. Kidneys treated with MAPC cells demonstrate improvement in clinically relevant functional parameters and injury biomarkers. This novel method of cell therapy delivery provides an exciting opportunity to recondition organs prior to clinical transplantation. One Sentence Summary: Ex-vivo reconditioning of human kidneys using Multipotent Adult Progenitor Cell therapy delivered during normothermic machine perfusion.