Expression of VEGF in Neonatal Urinary Obstruction: Does Expression of VEGF Predict Hydronephrosis?

BACKGROUND In animal studies, the inhibition of VEGF activity results in high mortality and impaired renal and glomerular development. Mechanical stimuli, like mechanical stretch in respiratory and circulatory systems, results in an elevated expression of VEGF. In animal models, the experimental urinary obstruction is associated with stretching of tubular cells and activations of the renin-angiotensin system. This results in the upregulation of vascular endothelial growth factor (VEGF) and TNF-alfa. MATERIAL/METHODS Tissue samples from urinary tract obstruction were collected and immunohistochemistry was performed in 14 patients (average age: 7.1±4.1 years). The control histology group consisted of ureteropelvic junction tissue from 10 fetuses after midtrimester artificial abortion. The fetuses did not have any failure at ultrasound screening and pathological examination. The mean gestational age was 20.6 weeks of gestation (±2.2SD). Expression of VEGF was detected with immunohistochemistry method. RESULTS Expression of VEGF was found in varying intensity in the submucosa and subserosa layers, but only in the test tissue (placental tissue). The tissue of the patients with urinary obstruction and the tissue of the fetal ureteropelvic junction without urinary obstruction were negative for expression of VEGF. The repeated examination showed negative cells and no color staining. CONCLUSIONS The pressure due to congenital urogenital obstruction resulting in mechanical stress in cells did not increase the expression of VEGF in young children in our study. To find a correlation between urogenital tract obstruction and increased expression of VEGF, we need to perform more examinations because the connection may be of therapeutic significance.