Abstract: TH-PO267

Microparticles in Oxidative Stress and Inflammatory Models of Kidney Injury

Session Information

Category: Acute Kidney Injury

  • 001 AKI: Basic

Authors

  • Campos, Begoña, University of Cincinnati, Cincinnati, Ohio, United States
  • Gleich, Brittany N, University of Cincinnati, Cincinnati, Ohio, United States
  • Saum, Keith Louis, University of Cincinnati, Cincinnati, Ohio, United States
  • Domenico, Karen M, Shriners Hospitals for Children, Cincinnati, Ohio, United States
  • Thakar, Charuhas V., University of Cincinnati, Cincinnati, Ohio, United States
Background

Acute kidney injury (AKI) is associated with significant morbidity, including remote organ dysfunction. In response to stress or injury cells release phenotypically and quantitatively distinct microparticles (MP's), representing both the cell type and metabolic stage (e.g. apoptosis, activation, proliferation). The objective of this study was to evaluate relelase of MP's from renal proximal tubular epithelial cells (RPTEC) in inflammatory and oxidative stress. We also examined MP's as putative biomarkers, and their role in remote organ cross-talk.

Methods

We used in vitro models of injury to human immortalized RPTEC line. Exposures of H202 (0.03 mM for 1 hour) and TNF-α (50 and 100 ng/ml for 72 hours were compared to controls (N = 3 sets). The presence of CD10, CD13 and CD146 proteins on the cells was evaluated by western blot and confocal microscopy. Flow cytometric analysis was used to detect the release of MP's containing CD10, CD13, and CD146. Analysis of MP's was performed using FlowJo software. MP levels were expressed as mean and standard deviations times 105 and compared by unpaired t-tests.

Results

Western blot and confocal microscopy, in controls and treated cells, confirmed the presence of CD10, CD13 and CD146 proteins on RPTEC. Under both oxidative stress (H2O2) and inflammatory stress (TNF-α) cells showed morphological changes associated with apoptosis. Compared to controls MP's were significantly increased in H202 treated cells: CD10 (0.456 vs 9.842; p = 0.013), CD13 (3.190 vs 53.882; p = 0.0001) and CD146 (5.991 vs 142.474; p = 0.0018). TNF-α treated cells at both concentrations also released CD10, CD13 and CD146 MP’s; however, only CD13 MP’s were statistically higher than controls at 100 ng/ml of TNF-α (26.67 vs 56.911; p 0.02). CD146 MP's showed a trend at both concentrations of TNF-α.

Conclusion

This is the first report of detection of microparticles (CD10 and CD13) specific to and derived from human RPTEC. Furthermore, we demonstrate a significant increase in the level of MP’s derived from renal cells that is specific to oxidative and inflammatory stress. Additionally, release of CD146 MP’s by stressed RPTEC could serve as ligand for endothelial activation, suggesting renal origins of organ cross-talk. Thus, MP's expressed by RPTEC could serve as putative biomarkers for AKI, and once released, may mediate organ cross-talk.

Funding

  • Clinical Revenue Support