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.