Angiogenesis is the process of new capillary formation from pre-existing vessels, occurring rarely under normal conditions. In contrast, there are many diseases, which are characterised by unrestricted new capillary growth. The process is under strict regulation determined by a dual, yet opposing balance of angiogenic and angiostatic factors that promote or inhibit neovascularization, respectively. Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are the most important direct proangiogenic factors. The aim of this study was to assess, in vitro, VEGF and bFGF release by mononuclear cells of healthy donors pre-incubated with sera from interstitial lung diseases patients. Human normal mononuclear cells after pre-incubation one hour at 37°C with sera from patients with sarcoidosis, extrinsic allergic alveolitis, systemic sclerosis or healthy donors were suspended in RMPI and cultured 24, 48 and 72 hours. Vascular endothelial growth factor and bFGF in cell supernatant and cell homogenate from culture were evaluated by sandwich enzyme-linked immunosorbent assay.
In cell culture supernatants and cell homogenates increase in VEGF concentration was observed on the three consecutive days. Concentration of bFGF was undetectable in the supernatant as well as in the homogenate of MNC pre-incubated with sera from patients, healthy donors or PBS in all examined groups. Significant (p < 0.001) increase of VEGF level in the cell supernatant after 72 hours of culture compared to cell homogenate was observed. The results suggest that VEGF released by MNC pre-incubated with ILD patients sera may be partly responsible for the results obtained previously in vivo in the Sidky and Auerbach assay.