IGF-1, IGFBP-3, VEGF and MMP-9 levels and their potential relationship with renal functions in patients with compensatory renal growth.

BACKGROUND

Mechanisms of compensatory renal growth (CRG) still remain a mystery. Various growth factors, including growth hormone, insulin-like growth factor-1 (IGF-1) have been implicated in different forms of CRG.

AIMS

To investigate the serum levels of IGF-1, vascular endothelial growth factor (VEGF - role in vascular remodelling), matrix metalloproteinase-9 (MMP-9 - essential for normal nephrogenesis) and correlation of renal function in patients with unilateral nephrectomized, agenesis and hypoplasic kidney.

METHODS

Thirty patients were included in this study. In group I, there were 10 patients with unilateral nephrectomy, while in group II, there were 10 patients with unilateral agenesis. As for group III, there were 10 patients with unilateral hypoplastic kidney. The serum levels of IGF-1, IGF-binding protein-3 (IGFBP-3), VEGF and MMP-9 were studied in all the cases. Clearance of creatinin (Ccr) and protein excretion were examined in the 24 h urine. CRG was determined with ultrasonography and scintigraphy. Twenty-six control subjects were also studied.

RESULTS

The levels of IGF-1, IGFBP-3, VEGF and MMP-9 were significantly higher in patients than in the control subjects (P < 0.001). Ccr and protein excretion levels were different in study groups than in those of the control group (P < 0.01). There were positive correlations between the serum levels of IGF-1 with IGFBP-3; IGF-1 with MMP-9; IGFBP-3 with MMP-9 (r = 0.825, P = 0.0001; P < 0.001 r = 0.611; P < 0.001 r = 0.585, respectively). There were negative correlations between GFR and the serum levels of IGF-1, IGFBP-3 and MMP-9 (P < 0.01 r = -0.708; P = 0.002 r = -0.803; P < 0.05 r = -0.442, respectively). Furthermore, there were positive correlations between proteinuria and the serum levels of IGF-1, IGFBP-3 and MMP-9 (P = 0.039 r = 0.600; P < 0.05 r = 0.456; P < 0.05 r = 0.424).

CONCLUSIONS

Increased IGF-1, IGFBP-3, VEGF and MMP-9 were observed in CRG in the follow-up period. IGF-1 and MMP-9 seemed to have increased in patients with CRG in defiance of the development of fibrosis. Moreover, IGF-1 and MMP-9 seem to be associated with reduced renal function and proteinuria.