ISSN: 2251-8363    eISSN: 2251-8819  
J Nephropathol. 2018;7(3):182-187.
doi:10.15171/jnp.2018.38

Original Article

Soluble urokinase-type plasminogen activator receptor as a biomarker for focal segmental glomerulosclerosis; a retrospective analysis

Miguel Verdelho 1, Ana Carina Ferreira 1 * , Maria Céu Santos 2, Mário Góis 1, Helena Viana 1, Fernanda Carvalho 1, Francisco Ribeiro 1, Fernando Nolasco 1

1 Nephrology Department, Hospital Curry Cabral, Lisboa, Portugal
2 Immunology Department, Centro Hospitalar Lisboa Central, Lisboa, Portugal

Abstract

Background: Focal segmental glomerulosclerosis (FSGS) is a clinicopathological syndrome that presents with proteinuria, usually in the nephrotic range and evidence of histologic lesions of focal and segmental glomerular sclerosis with diffuse foot-process effacement. Recently, suPAR (soluble urokinase-type plasminogen activator receptor) was proposed as the potential circulating causative factor for primary FSGS.

Objectives: We performed a cross-sectional study with the aim to determine whether there is a relationship between suPAR serum levels and primary FSGS. The secondary aim was to associate serum suPAR levels with kidney dysfunction.

Patients and Methods: We enrolled a total of 90 patients with both suPAR serum levels and proteinuria. From these, 61 patients performed a renal biopsy.

Results: The mean age was 49.8±17.2 years, 37 was females (60.7%) and 54 were Caucasian race (91.5%). FSGS was diagnosed in 30 patients (49%). suPAR levels were positive in 34 patients (55.7%) and negative in 27 (44.3%). Concerning the positive results, 17 patients had the histologic diagnosis of FSGS, which gives the test a sensibility of 28%. Concerning the negative results, 14 patients had a different histologic diagnosis other than FSGS, which gives the test a specificity of 23%. The predicted positive value was 50% and the predicted negative value was 52%. suPAR serum levels were not correlated with 24 hours proteinuria (P=0.5), but we found a positive correlation with C-reactive protein (P=0.037) and an inverse correlation with estimated glomerular filtration rate (eGFR) (P<0.001).

Conclusions: We found that a positive suPAR test is not a marker of FSGS, but it can be a marker of podocyte and glomerular lesion, as it is inversely correlated with renal function in a cohort of proteinuric patients. Further studies are needed to further validate suPAR as a specific biomarker of glomerular damage.

Implication for health policy/practice/research/medical education:

Some research groups proposed soluble urokinase-type plasminogen activator receptor (suPAR) as a potential circulating causative factor for primary focal segmental glomerulosclerosis (FSGS). In this study we obtained very low sensibility (28%) and specificity (23%) of SuPAR for FSGS, and very low predicted positive value (50%) and predicted negative value (52%) was seen too. We found an inverse correlation with eGFR (P<0.001). Our results show that suPAR test is not a marker of FSGS, but it can be a marker of podocyte and glomerular lesions in a cohort of proteinuric patients.

Please cite this paper as: Verdelho M, Ferreira AC, Santos MC, Góis M, Viana H, Carvalho F, et al. Soluble urokinase-type plasminogen activator receptor as a biomarker for focal segmental glomerulosclerosis; a retrospective analysis. J Nephropathol. 2018;7(3):187-192. DOI: 10.15171/jnp.2018.38

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