Abstract: FR-PO756

Urinary Podocyte mRNA and Urinary Podocalyxin Protein: Different Excretion Pattern between Proliferative and Non-Proliferative Glomerular Diseases

Session Information

Category: Glomerular

  • 1004 Clinical/Diagnostic Renal Pathology and Lab Medicine

Authors

  • Fukuda, Akihiro, Oita University, Yufu, Japan
  • Minakawa, Akihiro, University of Miyazaki, Miyazaki, Japan
  • Kikuchi, Masao, University of Miyazaki, Miyazaki, Japan
  • Sato, Yuji, University of Miyazaki, Miyazaki, Japan
  • Kurosawa, Hiroyuki, Denka Seiken Co., Ltd, Gosen, Japan
  • Hara, Masanori, Niigata Wellness (Iwamuro Health Promotion Center), Niigata, Japan
  • Fujimoto, Shouichi, University of Miyazaki, Miyazaki, Japan
Background

Podocyte depletion causes glomerulosclerosis, and persistent podocyte loss drives progression to end-stage kidney disease in most forms of glomerular diseases. Podocytes are resident on the urinary space side of the glomerular basement membrane, so that as they detach or die, their products can be identified in urine. Thus, the podocyte products in urine might be potential biomarkers to monitor glomerular disease activity and progression. Recently, both the urinary pellet podocyte (u-pod) mRNA excretion rate and urinary podocalyxin (u-PCX) protein levels have been used to monitor disease activity in various glomerular diseases. However, differences in these markers between various pathologies have not yet been investigated. By comparing the u-pod mRNA excretion rate to u-PCX protein levels in biopsy-proven glomerular diseases, we examined the significance of these markers in various glomerular diseases.

Methods

From January 2013 to March 2016, early morning urine samples were collected from 12 healthy volunteers and 184 patients with various kidney diseases (minor glomerular abnormality, n=15; MCNS, n=16; MN, n=17; IgAN, n=62; crescentic GN, n=24; lupus nephritis, n=11; others, n=39). We examined the u-pod mRNA excretion rate, u-PCX protein levels and urinary protein/creatinine ratio (u-PCR).

Results

The u-pod mRNA excretion rate was statistically correlated with u-PCX protein levels (r=0.37, p<0.001). Both the u-pod mRNA excretion rate and u-PCX protein levels were statistically correlated with u-PCR (r=0.52, p<0.001 and r=0.32, p<0.001, respectively). Interestingly, the u-pod mRNA excretion rate was significantly increased in crescentic GN, IgAN and LN (especially class IV) compared with controls but not in MCNS and MN, whereas the u-PCX protein levels were significantly increased in MN and LN (tendency for class V) compared with controls but not in other glomerular diseases.

Conclusion

Although the u-pod mRNA excretion rate and u-PCX protein levels were positively correlated, a higher u-pod mRNA excretion rate and higher u-PCX protein levels might be associated with proliferative glomerulonephritis and non-proliferative glomerulonephritis, respectively.