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Abstract: PO1540

Urinary NPHS2-mRNA in Relation to Glomerular and Tubular Damage Markers in Patients with Membranous Nephropathy

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • van den Berge, Bartholomeus Tideman, Radboudumc Afdeling Nierziekten, Nijmegen, Gelderland, Netherlands
  • van de Logt, Anne-Els, Radboudumc Afdeling Nierziekten, Nijmegen, Gelderland, Netherlands
  • Jansen, Jitske, Radboudumc Afdeling Pathologie, Nijmegen, Gelderland, Netherlands
  • Smeets, Bart, Radboudumc Afdeling Pathologie, Nijmegen, Gelderland, Netherlands
  • Van der vlag, Johan, Radboudumc Afdeling Nierziekten, Nijmegen, Gelderland, Netherlands
  • Wetzels, Jack F., Radboudumc Afdeling Nierziekten, Nijmegen, Gelderland, Netherlands
  • Maas, Rutger J., Radboudumc Afdeling Nierziekten, Nijmegen, Gelderland, Netherlands
Background

Measurement of podocyte-specific mRNA in patients’ urine samples has been proposed as a novel tool to monitor podocyte loss in glomerular disease, and may have prognostic value. In our hospital, we routinely measure timed urinary excretion of high- and low-molecular weight proteins as prognostic markers in patients with membranous nephropathy (MN). Here, we investigated the relationship between NPHS2-mRNA and high- and low-molecular weight proteins in patients with MN.

Methods

We included 35 patients with MN (80% male, median age 67, median eGFR 63). NPHS2-mRNA was measured in urinary pellets as described by Wickman et al. (JASN 2013). Normal values of urinary NPHS2-mRNA were obtained in spot urine samples of 19 healthy controls.

Results

Clinical characteristics and results of urinary measurement are shown in Table 1. Mean urinary NPHS2-mRNA/creatinine ratio (UPodCR) was 64 fold higher in patients with MN versus healthy controls. UPodCR showed weak but significant correlations with urinary IgG excretion and proteinuria selectivity index (Figure 1), but not with total proteinuria or eGFR (Table 1).

Conclusion

Urinary excretion of NPHS2-mRNA correlated significantly with protein markers of glomerular damage in patients with MN. However, correlations were weak. Prospective studies are needed to evaluate if urinary NPHS2-mRNA excretion holds independent prognostic value.

Table 1. Characteristics of patients with membranous nephropathy (N=35)
CharacteristicCorrelations with UPod
Serum creatinine (µmol/L)102 (82-124)0.02 (0.37)
Selectivity index (%)19.8 (12.7-23.2)0.12 (0.05)
UAlb (g/g creat)3.0 (2.2-5.1)0.02 (0.47)
UIgG (mg/g creat)143.2 (74.3-332.0)0.14 (0.03)
Ualpha-1m (mg/g creat)45.7 (25.3-67.6)0.03 (0.32)
Ubeta-2m (mg/g creat)1.6 (0.3-4.0)0.07 (0.14)
UPod (ng/g creat)4.4e-4 (1.6e-4-1.6e-3) 

Continuous variables are expressed as Median (interquartile range). Correlations are expressed in Spearman’s R2 (p-value). UAlb = Urinary albumin, UPod = Urinary NPHS2 mRNA.