The relationship between supar (soluble urokinase-typeplasminogen activator receptor) levels and treatmentresponse in patients with glomerulonephritis: A single-center experience

Background and Aims: suPAR (Soluble Urokinase-type Plasminogen Activator Receptor) is an important protein which is reported to increase in broad range of inflamattory processes from glomerular pathologies such as FSGS, nephrotic syndrome and proteinuria to sepsis, cardiovascular diseases, chronic renal failure and autoimmune diseases. It is speculated that suPAR deteriorates podocyte morphology and function by attaching and activating the β3 integrin on it. There is no consensus about at which concentrations and in which diseases its levels give significant results concerning this new biomarker predicted to increase especially in podocyte-damaging situations. We aimed to determine whether suPAR is a significant biomarker in glomerulonephritis for distinguishing patients with treatment reponse from patients without treatment reponse in our study. Materials and Methods: Blood samples were collected from 117 patients with biopsy- proven glomerulonephritis who have been following up in Sakarya University Education and Research Hospital, nephrology department, glomerulonephritis policlinic and 54 healthy individuals without a known chronic disease (control group). After centrifuge procedure, serums of blood samples were separated and stored in minus 80 freezer until analyze process. When targeted numbers of groups reached, blood samples were analyzed with kits financed by Scientific Research Project Coordinatorship of Sakarya University in the laboratory of our hospital and suPAR level results were recorded. Clinical and laboratory data were recorded along with demographical informations. Data collected from patient files of glomerulonephritis policlinic and lab results of control group were analyzed in NCSS (Number Cruncher Statistical System, 2007, Kaysville, Utah, USA) program. Results: For patient group consisting of 117 patients, 56,4% were male, mean age was 49,6 and mean follow up duration was 32,2 months. Mean proteinuria was 3,17±2,63 gr/day and mean eGFR was 69,91±35,58 ml/min/1.73m 2 . The most commonly 15 diagnosed glomerular disease was FSGS followed by Ig A nephropathy and MPGN respectively. While suPAR levels were higher in patient group than control group (p=0,001;p<0,01), significant relationship of suPAR levels were found neither with treatment reponse status (p=0,057;p>0,05) nor with severity of disease (p=0,605;p>0,05). Besides, there was also no significant relationship between suPAR levels and BMI (p=0,251;p>0,05). When data of all patients were analyzed, hematuria was observed to respond the treatment significantly (p=0,02;p<0,05), but when data of patients with treatment-resistence (54 patients undergoing immunosuppressive treament, 46% of the patient group) were analyzed, no treatment response of hematuria was observed (p=0,128;p>0,05). Mean BMI value of the patient group was higher than the control group (p=0,027;p<0,05). The most commonly used immunosuppressant agent among patients with treatment-resistence was prednisolone (%96,2). Conclusion: It has been shown that suPAR levels can distinguish a patient with glomerulonephritis from a healthy individual whereas relationship of suPAR levels exist neither with treatment reponse status nor with severity of disease in our study. As a result of our study, suPAR molecule was not evaluated as an 'useful biomarker' for assessing the treatment response and follow up of patients with glomerulonephritis. Nevertheless, more studies with larger patient groups must be done in order to clarify the relationship of suPAR levels with diagnosis, follow up and treatment processes.