Serum levels of VEGF and bFGF in hypoxic patients with exacerbated COPD

Hypoxia frequently complicates the course of chronic obstructive pulmonary disease (COPD). Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are the two most potent angiogenic factors and may play a role in adaptation to hypoxia. The aims of the study were to assess the serum levels of VEGF and bFGF and to evaluate their mutual relationship in hypoxic patients with exacerbated COPD. The study group consisted of 50 hypoxic (PaO2 53 mmHg) patients with exacerbated COPD. Control groups were 30 stable COPD patients with PaO2 70 mmHg, and 30 healthy blood donors. The serum concentrations of VEGF and bFGF were measured using commercial enzyme-linked immunoassay kits. Patients with exacerbated COPD had significantly higher serum VEGF levels (1,089.16 +/- 1,128.03 pg/mL) compared to those with stable COPD (197.68 +/- 178.06 pg/mL) (p < 0.0001) and healthy blood donor group (257.69 +/- 170.4 pg/mL) (p < 0.0001). Serum bFGF levels were significantly higher in the exacerbated COPD group (6.15 +/- 2.56 pg/mL) compared to control groups (p = 0.0001). Basic FGF was undetectable in the stable COPD and blood donor groups. Since VEGF and bFGF correlated significantly with the majority of factors investigated in COPD patients, multivariate analysis was performed. According to the step-wise regression analysis, VEGF was best determined by PaO2, WBC and IL-6. Basic FGF was best determined by PaO2 and pH. The highly significant, simple correlation between VEGF and bFGF was lost in multivariate analysis. This suggests that their correlation is not independent, but due to factors that remain in the model after step-wise regression. These are essentially linked to the level of hypoxia. Results of our study suggest that VEGF and bFGF production is stimulated in hypoxic patients with exacerbated COPD. Elevated levels of VEGF and bFGF may activate the process of neoangiogenesis, which may lead to increased perfusion and an improvement in tissue oxygenation in this group of patients.