Comparison of the levels of hepatocyte growth factor and vascular endothelial growth factor in aqueous fluid and serum with grades of retinopathy in patients with diabetes mellitus

Abstract

Aims: To determine the relation between the stages of diabetic retinopathy (DR) and the levels of hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) in aqueous fluid and serum.

Methods: Levels of HGF and VEGF in serum and aqueous humour obtained during ocular surgery were measured by enzyme linked immunosorbent assay in 58 diabetic patients with 32 non-diabetic patients (NDM) as controls. The patients with diabetes were classified into three groups according to the stage of DR: no DR (NDR; 15 cases), non-proliferative DR (NPDR; six cases), and proliferative DR (PDR; 37 cases).

Results: No significant differences were found between any of the groups in serum concentrations of HGF or VEGF. The aqueous HGF levels increased with the stage of DR: NDM, median 397 pg/ml, range 133-930 pg/ml; NDR, 371 pg/ml, 142-1536 pg/ml; NPDR, 455 pg/ml, 162-1007 pg/ml; and PDR, 638 pg/ml, 187-2222 pg/ml. The aqueous VEGF levels in PDR (median 212 pg/ml, range 14-1216 pg/ml) were significantly higher than in NDM (105 pg/ml, 9-203 pg/ml), but aqueous HGF concentrations were unrelated to those of VEGF.

Conclusion: The results of the present study suggest that both HGF and VEGF present in the ocular tissues may play important roles in the progression of DR.

Figure 1

The relation between the stages of diabetic retinopathy and the aqueous HGF levels. Aqueous concentrations of HGF in non-diabetic control subjects (NDM) and in diabetic patients without retinopathy (NDR), with non-proliferative diabetic retinopathy (NPDR), and with proliferative diabetic retinopathy (PDR). *p<0.05. The aqueous VEGF level in PDR was significantly higher (p<0.05) than in NDM.

Figure 2

The relation between the stages of diabetic retinopathy and the aqueous VEGF levels. Aqueous concentrations of VEGF in non-diabetic control subjects (NDM) and in diabetic patients without retinopathy (NDR), with non-proliferative diabetic retinopathy (NPDR), and with proliferative diabetic retinopathy (PDR). **p<0.01. The aqueous VEGF level in PDR was significantly higher than in NDM (p<0.001) and NDR (p=0.004).