609 - Utilization of urinary cells to detect nephrotoxicity of iron in children with chronic kidney disease
Sunday, April 27, 2025
8:30am – 10:45am HST
Publication Number: 609.7115
Hannah Federman, Weill Cornell Medicine, New York, NY, United States; Chantalle A. Campbell, Weill Cornell Medicine, New York, NY, United States; Heba El Sayed, Weill Cornell Medical College, Staten Island, NY, United States; Kanza Baqai, Weill Cornell Medicine, New York City, NY, United States; Oleh Akchurin, Weill Cornell Medical College, New York, NY, United States
Postdoctoral Fellow Weill Cornell Medicine New York, New York, United States
Background: Chronic kidney disease (CKD) affects over 200,000 children in the U.S. Disrupted iron metabolism, leading to renal anemia is a common CKD complication. Although iron supplementation is used for treatment, the role of iron in the kidney, especially in CKD, remains poorly understood, with toxicity being a significant concern. However, no clinically feasible tools currently exist to assess renal iron toxicity in patients or to account for these effects when prescribing iron to children with CKD. Objective: Validate catalytic iron content in exfoliated tubular epithelial cells (TECs) found in urine samples as a novel non-invasive measure of iron nephrotoxicity in children with CKD. Design/Methods: Fresh urine samples provided by children with CKD stages 2-4 and healthy controls were immediately processed for flow cytometry after urinary cells were pelleted, washed, passed through 30-micron filters, and stained with antibodies and probes. Live TECs were selected as CD45-AQP1+ population and categorized as labile iron pool (LIP)-HI or LIP-LO based on fluorescent intensity of FerroOrange, a probe that stains LIP. Kidney injury molecule 1 (KIM-1) staining was used to detect tubular injury. For validation that urinary TECs reflect kidney tissue TECs, we used mouse models of CKD, unilateral ureteral obstruction (UUO) and adenine diet. Results: On average, we recovered ~500,000 human urinary cells per 50 mL of urine, 50-80% of them alive by the time of flow cytometry, yielding 1,000-10,000 of live TECs per 50 mL of urine. In iron-naïve CKD patients (those not treated with iron), the LIP of urinary TECs was lower than in healthy controls, suggesting a protective response of TECs to chronic injury. The LIP of urinary TECs from CKD patients with high serum iron (≥70 µg/dL) and high TSAT (≥25%) was significantly higher than in those with lower circulating iron levels. Furthermore, KIM-1 expression was markedly induced in LIPHI urinary TECs. CKD mice displayed a concordance in LIP and KIM-1 expression between urinary and kidney tissue TECs.
Conclusion(s): Catalytic iron content measured in live exfoliated urinary tubular cells correlates with both tubular injury markers and systemic iron status, and therefore should be considered as a promising tool to detect renal iron toxicity in children with CKD.
