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Kidney Week

Abstract: PO0299

Dialysate Exposure Does Not Compromise the Function of Bioengineered Proximal Tubules for Bioartificial Kidney

Session Information

  • Bioengineering
    October 22, 2020 | Location: On-Demand
    Abstract Time: 10:00 AM - 12:00 PM

Category: Bioengineering

  • 300 Bioengineering

Authors

  • Masereeuw, Rosalinde, Universiteit Utrecht, Utrecht, Utrecht, Netherlands
  • Mihaila, Silvia M., Universiteit Utrecht, Utrecht, Utrecht, Netherlands
  • Stamatialis, Dimitrios, Universiteit Twente, Enschede, Overijssel, Netherlands
  • Middel, Igor R., Universiteit Utrecht, Utrecht, Utrecht, Netherlands
  • Verhaar, Marianne C., Universitair Medisch Centrum Utrecht, Utrecht, Utrecht, Netherlands
  • Gerritsen, Karin G., Universitair Medisch Centrum Utrecht, Utrecht, Utrecht, Netherlands
Background

Protein-bound uremic toxins (PBUTs) accumulate in plasma of end-stage kidney disease patients and are associated with a wide range of comorbidities. Their removal by conventional hemodialysis is severely limited, warranting the development of novel renal replacement therapies such as the bioartificial kidney (BAK). Recently, we developed bioengineered kidney tubules as functional BAK units capable of active PBUTs secretion via organic anion transporter-1 (OAT1). To accelerate their application, a comprehensive assessment under clinical-like conditions is essential. Here, we assessed the extent to which exposure to dialysate and uremic plasma would affect the viability and function of the kidney tubules.

Methods

Human conditionally immortalized proximal tubule epithelial cells equipped with OAT1 (ciPTEC-OAT1) exposed to medical-grade dialysate (10-240min) were evaluated for metabolic activity, membrane integrity (LDH release), inflammatory response (IL-6 and IL-8), oxidative stress (ROS) and OAT1 function (fluorescein uptake). Further, ciPTECs grown on biofunctionalized hollow fiber membranes were extraluminally exposed to dialysate fluid, intraluminally perfused with human uremic plasma (30min) and assessed for PBUTs clearance (indoxyl sulfate (IS), kynurenic acid (KA), L-kynurenine (L-Kyn), hippuric acid (HA) and indole-3-acetic acid (I3-AA)), determined by LC-MS/MS (n=7). Membrane integrity was evaluated by paracellular FITC-inulin leakage.

Results

Prolonged exposure (240min) of flat monolayers of ciPTEC-OAT1 to dialysate slightly reduced the metabolic activity to 80±4% (p<0.001) and OAT1 function to 81±5% (p<0.001) and an increased LDH release (from 10±2% in controls to 15±3%, p<0.05), without inducing the release of IL-6 or IL-8. After 30min, a 3.4±0.9 fold increase in ROS production was noticed. Still, exposure of ciPTEC-OAT1-containing hollow fiber membranes to dialysate enabled the concomitant clearance of five PBUTs (IS = 2980±1438; KA = 223±120; L-Kyn = 324±100; HA = 6547±1278 and I3-AA = 884±130 nmol/cm2, n=6-7), without compromising the membrane integrity as observed by FITC-inulin leakage (20±4 % vs 25±5%).

Conclusion

The demonstrated functionality of bioengineered kidney tubules in PBUT clearance under clinical-like conditions advances the development of a BAK.

Funding

  • Government Support - Non-U.S.