Abstract: SA-PO106

AKI Biomarker Expression in Glomeruli of Lupus Nephritis Biopsies

Session Information

Category: Glomerular

  • 1005 Clinical Glomerular Disorders

Authors

  • Liang, Kelly V., University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Emlet, David R., University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
  • Bastacky, Sheldon, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Palevsky, Paul M., University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Kellum, John A., University of Pittsburgh, Pittsburgh, Pennsylvania, United States
Background

Acute kidney injury (AKI) biomarkers urine insulin-like growth factor-binding protein 7 (IGFBP7), tissue inhibitor of metalloproteinases-2 (TIMP-2), and kidney injury molecule 1 (KIM-1) have been validated in critically ill as markers of tubular injury and cell-cycle arrest, but they have not been studied extensively in lupus nephritis (LN). Studies in animal models of LN suggest they may play a pathophysiologic role. Therefore, we sought to determine if IGFBP7, TIMP-2, and KIM-1 are expressed in human LN tissues.

Methods

Five frozen renal biopsies with LN class IV were identified from the Renal Pathology Department. Controls were human tissue from kidneys rejected for transplant. The samples were subjected to standard double-label indirect immunofluorescence with antibodies to IGFBP7, TIMP-2, and KIM-1 and appropriate fluorochrome-conjugated secondary antibodies. In vivo expression of biomarkers were determined semi-quantitatively using confocal microscopy.

Results

While the level of expression was variable from sample to sample, in every case, the levels of expression of IGFBP7, TIMP2, and KIM-1 were greater in glomeruli of LN biopsies compared to control kidney tissues. Figure 1 shows sample immunofluorescence images from a LN sample, a non-LN control tissue sample, and a negative control for each biomarker.

Conclusion

This is the first study to evaluate glomerular expression of TIMP-2 and IGFPB7 in glomeruli of patients with LN. IGFBP7, TIMP2, and KIM-1 expression was greater in glomeruli of LN biopsies compared to control kidney tissues. Therefore, further studies are warranted to determine if they may be useful biomarkers in LN and other glomerular disorders.

Funding

  • NIDDK Support