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Kidney Week

Abstract: SA-PO567

Microparticles Can Phenotype Ischemic and Nephrotoxic AKI

Session Information

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Campos, Begoña, University of Cincinnati, Cincinnati, Ohio, United States
  • Bockhorst, Samuel Paul, University of Cincinnati, Cincinnati, Ohio, United States
  • Saum, Keith Louis, University of Cincinnati, Cincinnati, Ohio, United States
  • Thakar, Charuhas V., University of Cincinnati, Cincinnati, Ohio, United States

Group or Team Name

  • Kidney Injury Translational Research Group
Background

Acute tubular necrosis is the major cause of acute kidney injury (AKI), occuring due to ischemia reperfusion injury (IRI) or nephrotoxicity (NT); however, it cannot be differentiated by biochemical or histological parameters. Although biomarkers allow earlier identification of AKI, they cannot discriminate cause-specificity, leading to impediment in translating novel therapies. Our prior work confirmed that CD10, CD13 and CD146 proteins on renal epithelial cells are released as microparticles (MP) upon exposure to oxidative or inflammatory stress. We evaluated whether these MP can discriminate IRI or NT in murine models.

Methods

In C57BL/6 mice, IRI was performed by clamping both renal pedicles for 30 minutes followed by reperfusion and NT was induced by injecting intraperitoneal (IP) Cisplatin at 20 mg/kg. Sham mice underwent surgery without clamp in IRI and IP normal saline in NT. Mice were euthanized at 48 hrs and examined by standard techniques for renal histology. Citrate poor plasma was collected at 0, 12, 48 hrs. Blood urea nitrogen (BUN), neutrophil gelatinase associated lipocalin (NGAL); and MP containing CD10, CD13 and CD146 were measured using flow cytometry and analyzed by flow jo software. MP were expressed as 105/ml, and compared within each model over time, and across models by Chi-square tests.

Results

AKI was confirmed in IRI and NT samples by histology, BUN and NGAL levels at 48 hrs. In IRI (48 hrs), CD10 and CD13 MP increased by 1.77 and 1.5 fold respectively, but CD146 declined by 1.7 fold from baseline. In contrast, NT model showed decline of MP quantity at 48 hrs relative to baseline in CD10, CD13 and CD146 by 1.5, 1.5 and 3.6 fold respectively. When examined across the models, then proportion of MP released at 48 hrs in IRI were 64% CD10, 6% CD13 and 30% CD146. Interestingly NT model showed distinctly different proportions: 6% CD10, 18% CD13 and 76% CD146 quantitatively. (p<0.0001 for comparison across models)

Conclusion

Despite similar biochemical, histological and biomarker parameters, MP quantity changed over time differently in each model. More importantly, the pattern of MP proportions almost switched across IRI and NT models, allowing discrimnation of ischemic and toxic cell injury. MP measured in plasma can phenotype AKI based on cause-specificity and can lead to development of novel diagnostic or therapeutic strategies.

Funding

  • Other NIH Support