Circulating VEGF and TGF-beta 1 in children with idiopathic nephrotic syndrome

Rationale: The implications of vascular endothelial growth factor (VEGF) an d transforming growth factor-beta (TGF-beta) on the development of proteinu ria were studied by measuring the mRNA and protein levels of VEGF and TGF-b eta1 in 43 children with primary nephrotic syndrome. Methods: Twenty-seven patients were in the active nephrotic phase at the ti me of sampling (Group 1), and 16 were in remission (Group 2). In Group 1, 1 6 were steroid-responders (Group la) and I I were nonresponders (Group 1b). Minimal change lesion (MCL) in 11 patients and focal segmental glomerulosc lerosis (FSGS) in 8 were confirmed by renal biopsy. The mRNA expressions of peripheral blood lymphocytes and the plasma levels of proteins were measur ed by semi-quantitative RT-PCR and ELISA, respectively. Results: Plasma VEGF concentration was higher in Group 1 (204+/-137 pg/mL) than Group 2 (91+/-72 pg/mL) (P=0.002). However, there was no significant d ifference either between Group 1a (184+/-146 pg/mL) and Group 1b (258+/-134 pg/mL) or between patients with FSGS (330 +/- 122 pg/mL) and those with MC L (146 +/- 112 pg/mL). The VEGF mRNA expression showed changes similar to V EGF protein expression, and there was no statistical significance. Plasma l evels and mRNA expressions of TGF-beta1 were similar in all groups. Conclusions: These results suggest that circulating VEGF is associated with proteinuria both in steroid-responsive and steroid-resistant primary nephr otic syndrome in children.