Kidney Week

Abstract: FR-PO1120

The Total Nephron Number and Responses to Corticosteroid Therapy in Patients with Minimal Change Nephrotic Syndrome

Session Information

• Glomerular Diseases: Clinical, Outcomes, Trials - II
  October 26, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

• Sasaki, Takaya, The Jikei University School of Medicine, Minato-ku, ToKyo, Japan

Takaya Sasaki,

• Tsuboi, Nobuo, The Jikei University School of Medicine, Minato-ku, ToKyo, Japan

Nobuo Tsuboi,

• Okabayashi, Yusuke, The Jikei University School of Medicine, Minato-ku, ToKyo, Japan

Yusuke Okabayashi,

• Haruhara, Kotaro, The Jikei University School of Medicine, Minato-ku, ToKyo, Japan

Kotaro Haruhara,

• Kanzaki, Go, The Jikei University School of Medicine, Minato-ku, ToKyo, Japan

Go Kanzaki,

• Koike, Kentaro, The Jikei University School of Medicine, Minato-ku, ToKyo, Japan

Kentaro Koike,

• Yokoo, Takashi, The Jikei University School of Medicine, Minato-ku, ToKyo, Japan

Takashi Yokoo,

Background

The etiologies of minimal change nephrotic syndrome (MCNS) remain largely unknown; however, indirect evidence suggests that the weight at birth, which is related to the total nephron number, may affect the response to corticosteroid therapy. This study investigated the involvement of the total nephron number in the clinical course of MCNS.

Methods

Patients who exhibited acute-onset nephrotic syndrome, with a histological diagnosis of MCNS, were retrospectively analyzed. The total nephron number was estimated using a simplified method based on the combined use of unenhanced computed tomography and the non-sclerotic glomerular density of renal biopsy specimens. The single nephron glomerular filtration rate (snGFR) and single nephron urinary protein excretion (snUPE) values were calculated by dividing the eGFR or UPE by the total nephron number. The glomerular volume (GV) was estimated by the measured mean glomerular area.

Results

A total of 38 MCNS patients were analyzed. The estimated total nephron number ranged from 140,000 to 1,800,000 per kidney among the patients and was inversely correlated with GV (r=-0.433, p=0.007). At the time of the diagnosis, the snGFR and snUPE values of the low-nephron group were significantly higher than those of the high-nephron group (139 vs 58 nl/min/1.73m² and 15.3 vs 7.1 µg/day, respectively). There was no significant difference in the total amount of UPE (7.4 vs 8.7 g/day) or the selectivity index (0.05 vs 0.05) of the groups. The reduction in snUPE (Figure A) and the time to complete remission (Figure B) during corticosteroid therapy were significantly slower in the low-nephron group, with no difference in the dose of corticosteroids. The total nephron number was found to be associated with the UPE at four weeks after the initiation of corticosteroid therapy, independent of age and the renal function.

Conclusion

Individual differences in the total nephron number in MCNS patients may influence the responses to corticosteroid therapy, possibly through the alteration of the single nephron dynamics.