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Abstract: FR-PO451

Mesothelial and Endothelial Cell Barrier Characterization in Health, CKD, and Peritoneal Dialysis

Session Information

Category: Dialysis

  • 702 Dialysis: Home Dialysis and Peritoneal Dialysis

Authors

  • Marinovic, Iva, UniversitatsKlinikum Heidelberg, Heidelberg, Baden-Württemberg, Germany
  • Bartosova, Maria, UniversitatsKlinikum Heidelberg, Heidelberg, Baden-Württemberg, Germany
  • Herzog, Rebecca, Medizinische Universitat Wien, Wien, Austria
  • Sacnun, Juan Manuel, Medizinische Universitat Wien, Wien, Austria
  • Zhang, Conghui, UniversitatsKlinikum Heidelberg, Heidelberg, Baden-Württemberg, Germany
  • Hoogenboom, Robin, Medizinische Universitat Wien, Wien, Austria
  • Ridinger, David, Ruprecht Karls Universitat Heidelberg Kirchhoff-Institut fur Physik, Heidelberg, Baden-Württemberg, Germany
  • Levai, Eszter, UniversitatsKlinikum Heidelberg, Heidelberg, Baden-Württemberg, Germany
  • Krunic, Damir, Deutsches Krebsforschungszentrum, Heidelberg, Baden-Württemberg, Germany
  • Bestvater, Felix, Deutsches Krebsforschungszentrum, Heidelberg, Baden-Württemberg, Germany
  • Hausmann, Michael, Ruprecht Karls Universitat Heidelberg Kirchhoff-Institut fur Physik, Heidelberg, Baden-Württemberg, Germany
  • Zarogiannis, Sotirios G., UniversitatsKlinikum Heidelberg, Heidelberg, Baden-Württemberg, Germany
  • Kratochwill, Klaus, Medizinische Universitat Wien, Wien, Austria
  • Schmitt, Claus Peter, UniversitatsKlinikum Heidelberg, Heidelberg, Baden-Württemberg, Germany
Background

Solute transport across cellular barriers is defined by tight-junctions (TJ) and transmembrane transporters. Cell-specific expression and regulation by peritoneal dialysis (PD) is unknown.

Methods

Quantitative and functional cellular in vitro and peritoneal ex vivo barrier studies included RNAseq of polarized cell monolayers, Transwell experiments and tissue multi-omics followed by digital analysis.

Results

RNA sequencing of polarized human peritoneal mesothelial, immortalized pleural, umbilical vein and cardiac microvascular endothelial cells demonstrated distinct junction, transmembrane and transcytosis related transcripts across cell lines. Next to the tissue origin and transformation status, major differences in cell adhesion and migration, vasculature development and growth factor response were identified. Sealing TJ, claudin (CLDN)1 was expressed only in mesothelial cells, CLDN5 in endothelial cells. Findings were reconfirmed by western blot and immunofluorescence in vitro and in human parietal peritoneum ex vivo. Super resolution microscopy revealed less CLDN5 clustering in microvascular endothelial cells and transepithelial resistance was 50% lower compared to the three other cell lines; 4- and 10-kDa dextran permeability was higher.
Multi-omics analyses from microdissected omental arterioles of children on high-GDP PD demonstrated downregulation of junctions and transcytosis as compared to non-CKD, ESRD and low-GDP PD treated children, transcellular transporter expression was comparable. The parietal peritoneal endothelial to mesothelial surface area available for exchange was age dependently 1.5 to 2-fold higher and increased with low-GDP PD. PD induced arteriolar TJ regulation was reconfirmed in the parietal peritoneum. Arteriolar and mesothelial pore-forming junctions CLDN2/4/15 correlated with transport function in peritoneal equilibration tests.

Conclusion

We provide the first comprehensive analysis of peritoneal solute transporters and their regulation by ESRD and PD. Mesothelial and endothelial sealing and transporter abundance differs substantially, associates with PD membrane function and indicates a functional role of both cellular barriers.

Funding

  • Government Support – Non-U.S.