Mesenchymal stromal cells infused via the renal artery are retained and survive in ischemic porcine kidney

J.M. Sierra Parraga, M. Eijken, C. Andersen, C. Moers, R.J. Ploeg, B. Møller, C.C. Baan, M.J. Hoogduijn, B. Jespersen

Friday 16 march 2018

11:00 - 11:10h at Van Weelde Zaal

Categories: Basic / translational research, Session (parallel)

Parallel session: Parallel session 12: Basic/translational research

Introduction

Donor organ shortage is one of the main problems in kidney transplantation. The increase in donor kidney pool comes with the use of expanded criteria donor organs. Therefore, a number of techniques are arising to improve organ quality, such as machine perfusion in combination with cell therapy. Mesenchymal stem cells (MSC) have tissue regenerative capacities exerted by paracrine secretion of different cytokines and physical interaction with surrounding cells.

Materials and methods

Porcine MSC from adipose tissue were isolated to carry out the experiments. A model of unilateral ischemia-reperfusion injury by clamping the renal artery for 1 hour was established. 10 million fluorescently labelled MSC with Qtracker beads were infused directly through the renal artery during 10 minutes. Fluorescent MSC were detected using flow cytometry. Before, during and after the infusion, blood samples were taken from the renal vein to assess if MSC were leaving the kidney. After 30 minutes or 8 hours both kidneys were retrieved and biopsies were collected from multiple sites. These biopsies were mechanically disrupted and enzymatically digested to a single cell suspension and analyzed by flow cytometry. Slices from paraffin-embedded biopsies were stained by H&E and analyzed by microscopy to identify the exact localization of the MSC.

Results

MSC left the kidney (up to 2000 MSC/ml blood) during the infusion procedure, after which very low fluorescent cells were detected in renal venous blood (300 MSC/ml). No MSC were found in arterial blood. Dissociated renal cortex and medulla revealed that most MSC were present in renal cortex (8000-20000 MSC/gram) but a number of individual MSC were detected in the medulla (1000-3000 MSC/gram). From these MSC inside renal tissue, 80% were alive. A small population of MSC was found in lung (200-400 MSC/ gram). MSC were detected by microscopy in renal cortex, mainly at glomeruli, but individual MSC were found also in tubuli, vessels and medulla .

Conclusions

Infusion of MSC through the renal artery can successfully deliver MSC throughout the kidney. MSC were retained particularly in glomeruli for at least 8 hours. We were able to estimate the relative retainment and localization of MSC in the kidney. These studies will pave the way for survival studies in this large animal model aiming for future clinical studies with targeted delivery of MSC in renal disease, eg. in transplantation of high risk donor organs.