ASN's Mission

ASN leads the fight to prevent, treat, and cure kidney diseases throughout the world by educating health professionals and scientists, advancing research and innovation, communicating new knowledge, and advocating for the highest quality care for patients.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005

email@asn-online.org

202-640-4660

The Latest on Twitter

Kidney Week

Abstract: TH-PO1112

Donor Nephrectomy Selectively Increases Proximal Tubular Proteins in Urinary Vesicles

Session Information

Category: Transplantation

  • 1902 Transplantation: Clinical

Authors

  • Blijdorp, Charles J., Erasmus Medical Center, Rotterdam, Netherlands
  • Severs, David, Erasmus Medical Center, Rotterdam, Netherlands
  • Budde, Ricardo, Erasmus Medical Center, Rotterdam, Netherlands
  • Hoenderop, Joost, Radboud university medical center, Nijmegen, Netherlands
  • Bindels, René J., Radboud university medical center, Nijmegen, Netherlands
  • Cuevas, Catherina A., Erasmus Medical Center, Rotterdam, Netherlands
  • Zietse, Robert, Erasmus Medical Center, Rotterdam, Netherlands
  • Hoorn, Ewout J., Erasmus Medical Center, Rotterdam, Netherlands
Background

Donor nephrectomy causes hyperfiltration and hypertrophy of the remaining kidney. Uninephrectomy in rats causes a selective increase in proximal tubular proteins. Accordingly, we hypothesize that human donor nephrectomy increases proximal tubular proteins.

Methods

Nineteen kidney donors were included in this study. Kidney volume was calculated from CT scans prior to donation. Urine was collected prior to and three months after donor nephrectomy. Urinary extracellular vesicles (uEVs) were isolated and used as non-invasive read-out for renal tubular protein abundance. uEVs were quantified using nanoparticle tracking analysis. The following proteins were analyzed in uEVs using ultracentrifugation and immunoblotting: NHE3, NaPi-IIa and cubilin (proximal tubule), NKCC2 (thick ascending limb), NCC (distal convoluted tubule), and AQP2 (collecting duct). Relative protein abundance was expressed per remaining kidney volume.

Results

Donor nephrectomy reduced kidney volume by 50±3%, creatinine clearance by 38±10%, and uEV excretion by 20%. The relative abundance of proximal tubular proteins in uEVs increased significantly, whereas no change occurred in distal nephron proteins (Figure).

Conclusion

Donor nephrectomy selectively increases proximal tubular proteins in uEVs. This may be due to hyperfiltration and hypertrophy occurring in this segment. It may also explain why a kidney volume reduction of ~50% is accompanied by a decrease in uEV excretion of only 20%. These results provide insight in the changes after kidney donation and are relevant when analyzing uEVs in kidney donors.

Funding

  • Private Foundation Support