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Abstract: FR-PO861

Estimation of Nephron Number and Related Single Nephron Parameters in Patients with Idiopathic Membranous Nephropathy

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Okabayashi, Yusuke, The Jikei University School of Medicine, Tokyo, Japan
  • Tsuboi, Nobuo, The Jikei University School of Medicine, Tokyo, Japan
  • Marumoto, Hirokazu, The Jikei University School of Medicine, Tokyo, Japan
  • Sasaki, Takaya, The Jikei University School of Medicine, Tokyo, Japan
  • Haruhara, Kotaro, The Jikei University School of Medcine, South Yarra, Victoria, Australia
  • Kanzaki, Go, The Jikei University School of Medicine, Tokyo, Japan
  • Koike, Kentaro, The Jikei University School of Medicine, Tokyo, Japan
  • Yokoo, Takashi, The Jikei University School of Medicine, Tokyo, Japan
Background

Studies using animal models suggested that glomerular hyperfiltration as well as impaired hydraulic permeability play a crucial role in the progression of membranous nephropathy. To date, total nephron number and the related single nephron parameters have not been evaluated in patients with idiopathic membranous nephropathy (IMN) due to technical difficulties in counting nephrons in a clinical setting.

Methods

The total nephron number was calculated using a simplified method based on combined use of unenhanced computed tomography and stereology-based estimation of non-sclerotic glomerular density in biopsy specimens (Sasaki T et al. 2018, ASN). Single-nephron glomerular filtration rate (SNGFR) and single-nephron urinary protein excretion (SNUPE) were calculated by dividing eGFR or UPE by total nephron number, respectively.

Results

A total 49 IMN patients was included (age, 60 ± 14 years; 49 % male; UPE 4.1 ± 3.1 g/day). The total nephron number ranged from 197,561 to 1,824,272 per kidney. Compared to patients with CKD stage 1 or 2, the SNGFR showed a tendency to be low in patients with CKD stage 3 or higher. Patients with CKD stage 3 or higher were characterized by elevated SNUPE level (Figure). Nephron number and the related single nephron parameters were not associated with Ehrenreich-Churg stage of the glomerular basement membrane (GBM) lesions.

Conclusion

This study for the first time estimated total nephron number and the related single nephron parameters in IMN patients. Impaired single nephron functions may be involved in IMN patients with advanced-stage CKD regardless of severity of GBM lesions.