Kidney Week

Abstract: TH-PO1085

Enrichment of Osteopontin Protein in Urine Extracellular Vesicles and in Demineralized Calcium Oxalate Kidney Stone Specimens: Implications for a Novel Biomarker

Session Information

• Pathology and Lab Medicine
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Pathology and Lab Medicine

• 1700 Pathology and Lab Medicine

Authors

• Bala, Niharika, University of Florida, Gainesville, Florida, United States

Niharika Bala, MS

• Shahzad, Zenab, University of Florida, Gainesville, Florida, United States

Zenab Shahzad, MBBS

• Bird, Vincent G., University of Florida, Gainesville, Florida, United States

Vincent G. Bird, MD

• Zhou, Christopher, University of Florida, Gainesville, Florida, United States

Christopher Zhou, MD

• Smith, Jordan M., University of Florida, Gainesville, Florida, United States

Jordan M. Smith, MD

• Donelan, William LePage, University of Florida, Gainesville, Florida, United States

William LePage Donelan, PhD

• Khan, Saeed R., University of Florida, Gainesville, Florida, United States

Saeed R. Khan, PhD, FASN

• Sattari, Maryam, University of Florida, Gainesville, Florida, United States

Maryam Sattari, MD

• Kazory, Amir, University of Florida, Gainesville, Florida, United States

Amir Kazory, MD, FASN

• Ruchi, Rupam, University of Florida, Gainesville, Florida, United States

Rupam Ruchi, MD, FASN

• Alli, Abdel A., University of Florida, Gainesville, Florida, United States

Abdel A. Alli, PhD, MPH

Background

Recurrent kidney stone (KS) formation represents a major public health issue, affecting over 500,000 people per year in the United States. The rising prevalence has heightened interest in tools and assays to stratify the risk of stone recurrence in individual patients. Urinary extracellular vesicles (uEVs), released predominantly from urinary tract cells, are a promising candidate for a stone recurrence risk assay, as they have been shown to induce renal tubular cell death that may lead to Randall’s plaque and stone formation. We hypothesized that the proteomic profile of uEVs from calcium oxalate (CaOx) KS formers correlates with proteins enriched in the matrix of demineralized CaOx KS specimens.

Methods

We examined CaOx stone formers aged 30–79 years with comorbid hypertension and diabetes mellitus, and healthy volunteers as controls. uEVs were isolated by ultracentrifugation, characterized by nanoparticle tracking analysis and Western blotting for established markers, then lysed for nano LC/MS/MS based proteomics with bioinformatic analysis. Mouse inner medullary collecting duct (mIMCD3) cells were treated with CaOx or vehicle and probed for changes in expression of proteins including osteopontin (OPN).

Results

Bioinformatic and pathway analyses of the uEV proteomic dataset from KS formers versus healthy subjects showed that the most significantly altered proteins were associated with the plasma membrane, transport, stress response, and cellular organization. ELISA demonstrated higher OPN in uEVs from KS formers (320.29+/-14.01 ng/mL) than in controls (174.01+/-19.05 ng/mL). Western blotting and fluorescence microscopy showed that CaOx treatment increased OPN protein expression in mIMCD3 cells, and OPN was abundantly present in the matrix of demineralized CaOx KS specimens. Western blotting and densitometry also showed downregulation of prostaglandin E2 (Veh:4.23+/-0.24; CaOx:0.17+/-0.14) and E-cadherin (Veh:3.23+/-0.17; CaOx:1.21+/-0.34) in CaOx-treated mIMCD3 cells.

Conclusion

Our findings indicate that uEVs may serve as the basis for a non-invasive diagnostic tool to stratify patients according to their risk of future stone recurrence. This approach could provide patients and clinicians with information to guide targeted prevention strategies, helping to lessen the burden of kidney stone disease on patients and the healthcare system.

Funding

• NIDDK Support