Kidney Week

Abstract: TH-PO1200

Nephron Number and Glomerular Morphometry After Unilateral Nephrectomy in Children

Session Information

• Pediatric Nephrology: CV Health, CKD, AKI, Dialysis, Transplantation, and Health Services Research
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Pediatric Nephrology

• 1800 Pediatric Nephrology

Authors

• Habben, Chase, Mayo Clinic Minnesota, Rochester, Minnesota, United States

Chase Habben, MD

• Nizam, Mohamad Hasan, Mayo Clinic Minnesota, Rochester, Minnesota, United States

Mohamad Hasan Nizam, MD

• Rule, Andrew D., Mayo Clinic Minnesota, Rochester, Minnesota, United States

Andrew D. Rule, MD, MS, FASN

• Denic, Aleksandar, Mayo Clinic Minnesota, Rochester, Minnesota, United States

Aleksandar Denic, MD, PhD

• Hanna, Christian, Mayo Clinic Minnesota, Rochester, Minnesota, United States

Christian Hanna, MD, MS, FASN

Background

Nephron endowment and glomerular morphometry in living children are poorly characterized. Age-related changes in nephron number, glomerular structure, and compensatory adaptation may inform kidney functional reserve after nephrectomy

Methods

We retrospectively studied glomerular morphometry in 33 children undergoing unilateral nephrectomy for Wilms tumor. Preoperative CT imaging of the unaffected kidney was used to assess kidney and cortical volume. Histologic analysis from nephrectomy specimens was used to estimate glomerular volume, glomerular density, percentage of globally sclerotic glomeruli, and total nephron number (estimated as glomerular density x cortical volume). Associations with age and kidney function were evaluated using Spearman correlations (rs). Post-nephrectomy kidney function and residual eGFR relative to pre-nephrectomy function were assessed

Results

Median age (IQR) was 4.0 (2.8-7.4) yrs, and pre-nephrectomy eGFR was 139.5 ± 39.4 mL/min/1.73m². With increasing age, kidney and glomerular volumes increased, whereas glomerular density declined; estimated nephron number remained stable (Fig). Larger glomerular volume was associated with lower postoperative eGFR at 6 months, 1 year, and 2 years (rs= -0.46, -0.40, and -0.46, respectively; p≤0.01), whereas higher glomerular density correlated with higher postoperative eGFR (rs=0.42 and 0.41 at 6 months and 1 year, respectively; p=0.02 for both). Postoperative eGFR remained stable during follow-up. Residual eGFR averaged 94.1% and 87.5% of pre-nephrectomy kidney function at 6 and 12 months, respectively. None of the morphometric parameters were associated with residual eGFR

Conclusion

During childhood, nephron number is stable with kidney growth from enlarging nephrons. Following unilateral nephrectomy, most children preserved a high proportion of pre-nephrectomy kidney function, suggesting substantial compensatory adaptation.

Funding

• NIDDK Support