Kidney Week

Abstract: FR-PO097

Flow-Cytometric Quantification of Urine Kidney Epithelial Cells Specifically Reflects Tubular Damage and Extent of Injury in Acute Kidney Diseases

Session Information

• AKI: Diagnosis and Outcomes
  October 25, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

• 102 AKI: Clinical, Outcomes, and Trials

Authors

• Wagner, Leonie Felicitas, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Leonie Felicitas Wagner, MD

• Kujat, Jacob, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Jacob Kujat

• Langhans, Valerie Stephanie, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Valerie Stephanie Langhans

• Prskalo, Luka, Deutsches Rheuma-Forschungszentrum Berlin, Berlin, Berlin, Germany

Luka Prskalo

• Goerlich, Nina, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Nina Goerlich, DrMed

• Grothgar, Emil, Deutsches Rheuma-Forschungszentrum Berlin, Berlin, Berlin, Germany

Emil Grothgar

• Metzke, Diana, Deutsches Rheuma-Forschungszentrum Berlin, Berlin, Berlin, Germany

Diana Metzke

• Baumgart, Sabine, Deutsches Rheuma-Forschungszentrum Berlin, Berlin, Berlin, Germany

Sabine Baumgart, PhD

• Ochs, Matthias, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Matthias Ochs, MD

• Timm, Sara, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Sara Timm

• Schreiber, Adrian, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Adrian Schreiber, DrMed

• Enghard, Philipp, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Philipp Enghard, DrMed

• Klocke, Jan, Charite Universitatsmedizin Berlin, Berlin, Berlin, Germany

Jan Klocke, MD

Background

Despite tubular injury being one of the main mechanisms driving acute kidney injury (AKI), clinicians still have a limited diagnostic repertoire to precisely monitor damage to tubular epithelial cells (TEC). In our previous work we used single cell sequencing to identify TEC subsets as main component of the urine signature in AKI. The aim of this study was to establish TEC as a clinical marker for tubular damage.

Methods

In total, 195 patients were analyzed. To compare mRNA with protein expression, we collected urine samples of 7 patients with AKI and glomerular disease. By aligning single-cell transcriptomes and TEC-surface proteins using CITE-Seq (Cellular Indexing of Transcriptomes and Epitopes by Sequencing), we developed a protocol for flow cytometric quantification of CD10/CD13+ proximal and CD227/CD326+ distal TEC in urine. The marker combinations were confirmed in healthy kidney biopsies. We validated our approach across 3 cohorts with 188 patients, including patients with AKI (n=63), ANCA-associated vasculitis with active disease and stable remission (AAV, n=110) and healthy and in-patient controls (n=15).

Results

Our findings demonstrate that CD10/CD13 and CD227/CD326 adequately identify proximal and distal urinary TEC respectively. Both proximal and distal urinary TEC counts correlate with the severity of AKI based on KDIGO stage (each p < 0.001) and can successfully discriminate AKI from healthy controls (AUROC = 0.938/0.919) as well as glomerular disease (AUROC = 0.818/0.821). Patients with AAV also present with elevated amounts of urinary TEC compared to healthy controls (p < 0.05), albeit to a lesser extent.

Conclusion

We propose urinary CD10/CD13+ and CD227/CD326+ TEC counts as a specific, non-invasive marker for tubular injury in AKI. Our protocol provides the basis for a deeper phenotypic analysis of urinary TEC.