Relationship of potential biomarkers of interstitial cystitis/painful bladder syndrome

Abstract

BACKGROUND: Biomarker identification fulfills the need for simple, accurate, and non-invasive diagnostic methods for interstitial cystitis/painful bladder syndrome (IC/PBS). The simultaneous study of cytokines and growth factors is essential for understanding the role of biomarkers.
 AIM: This work determines the concentration of interleukins (IL) 6 and 8, nerve growth factor (NGF), heparin-binding epidermal growth factor (HB-EGF), and their relationship in patients with IC/PBS.
 MATERIALS AND METHODS: This study examined 126 female patients with IC/PBS, with a mean age of 46.714.0 years. The disease duration averaged 6.02.8 years. The control group consisted of 20 women without IC/PBS, with a mean age of 35.39.7 years. The level of IL-6 and IL-8 in blood serum and urine was determined by ELISA. The NGF and HB-EGF levels were determined by ELISA using the appropriate test kits. Statistical analysis was performed using SPSS software version 15.0. The Students t-test and Spearmans correlation coefficient were calculated.
 RESULTS: In patients with IC/PBS, blood levels of IL-6 and IL-8 exceeded the control indicator by 65.99% (t=4.62, p=0.000) and by 67.14% (t=2.81, p=0.006), respectively, the NGF level exceeded it by 8.82% (t=0.10, p=0.920), and the HB-EGF level decreased by 30.84% (t=0.62, p=0.537). In urine, the level of IL-6 in IC/PBS was increased by 52.94% (t=7.62, p=0.000), IL-8 level was increased by 57.53% (t=2.01, p=0.049), NGF was increased by 50.44% (t=2.06, p=0.043), and HB-EGF level was increased by 56.44% (t=2.01, p=0.049). Cytokines correlated with growth factors with weakly bound in blood and urine (p 0.05). A strong, direct relationship was registered between the urine levels of NGF and HB-EGF (r=+0.987, p 0.05).
 CONCLUSIONS: Correlations between IL-6 and IL-8 with NGF and HB-EGF in urine indicate an increased risk of damage to the bladder epithelium. The increase in urinary HB-EGF is a response to a significant increase in urinary NGF and may be a bladder epithelial defense mechanism.