Kidney Week

Abstract: FR-PO1187

Tubular Secretory Function and Tubular Biomarkers in Living Kidney Donors: A Pilot Study

Session Information

• Transplantation: Clinical - Rejection, Biomarkers, and Pharmacology
  October 23, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

• 2002 Transplantation: Clinical

Authors

• Fernandez Yepez, Ana K., Instituto Nacional de Cardiologia Ignacio Chavez, Mexico City, Mexico

Ana K. Fernandez Yepez, MS, MSc

• Rodriguez-Iturbe, Bernardo, Instituto Nacional de Cardiologia Ignacio Chavez, Mexico City, Mexico

Bernardo Rodriguez-Iturbe, MD

• Seegmiller, Jesse C., University of Minnesota Twin Cities, Minneapolis, Minnesota, United States

Jesse C. Seegmiller, PhD

• Traslaviña, Fernando, Instituto Nacional de Cardiologia Ignacio Chavez, Mexico City, Mexico

Fernando Traslaviña, MS

• Camil Escalante, Alexa, Instituto Nacional de Cardiologia Ignacio Chavez, Mexico City, Mexico

Alexa Camil Escalante, MS

• Madero, Magdalena, Instituto Nacional de Cardiologia Ignacio Chavez, Mexico City, Mexico

Magdalena Madero, MD

Background

Living kidney donation causes ∼50% nephron mass reduction, yet tubular secretory function, mediated by organic transporters (OCTs, OATs) has not been longitudinally characterized in donors. As a proof-of-concept study, we assessed the feasibility of serially measuring tubular secretions (TScr, TSfur) alongside urinary tubular biomarkers at baseline, 3 months, and 36 months post-nephrectomy

Methods

7 living donors were evaluated at Instituto Nacional de Cardiología Ignacio Chávez (baseline, 3 months & 36 months post-nephrectomy) using a 1 hour functional challenge (oral creatinine 5 g + IV furosemide 1 mg/kg) to stimulate TScr via OCTs and TSfur via OATs. eGFR, Urinary furosemide, serum and urinary creatinine, KIM-1, IL-18, a1MG, UMOD, ammonium and EGF were determined

Results

7 donors (44 years, 60% female) completed all assessments. eGFR declined 17.85±18.18 ml/min/1.73m² at 36 months (p<0.05). In contrast, the stimulated response of TScr and TSfuro were largely unchanged with only a non-significant reduction trend in TScr (slope=−0.11, R²=0.34, p=0.055). There were significant changes in the 3-month post-nephrectomy of UMOD, a1MG, and EGF but not correlated with the TScr and TSfuro

Conclusion

This proof-of-concept study supports the feasibility of serial tubular secretion assessment in living donors. TScr and TSfuro remained stable from 3–36 months and were independent of GFR changes, supporting the need for larger prospective studies on tubular secretory capacity

Table 1. Characteristics and biomarkers prior and post-nephrectomy.