Impact of photodynamic inactivation (PDI) on bFGF, HGF, KGF, TGFß1 and VEGF secretion of keratocytes in vitro

Purpose Photodynamic inactivation (PDI) may eliminate the microorganisms from the infected cornea by damages caused through free oxygen radicals, or even by supporting different stages of activation of keratocytes and inflammatory cell response. The purpose of this study was to determine the impact of PDI on bFGF, HGF, KGF, TGFß1 and VEGF secretion of keratocytes in vitro. Methods Primary human keratocytes were isolated by digestion in collagenase A (1 mg/ml) from human corneal buttons, and cultured in DMEM/Ham’s culture medium supplemented with 10% FCS. Keratocytes underwent illumination (670 nm) for 13 minutes following exposure to 100 nM concentration of photosensitizer chlorin e6 (Ce6) in the culture medium. One day after treatment, bFGF, HGF, KGF, TGFß1 and VEGF release of the cells was determined using enzyme‐linked immunosorbent assay (ELISA). Results One day after PDI, the secretion of bFGF was 1.58, of HGF 1.61, of KGF 0, of TGFß1 2.83 and of VEGF 9.01 pg/µg protein. The secretion of bFGF decreased (p=0.007) significantly one day after PDI, compared to controls. In HGF, KGF, TGFß1 and VEGF secretion no significant changes could be detected. Using Ce6 or illumination only, bFGF, HGF, KGF, TGFß1 and VEGF secretion of keratocytes did not change significantly. Conclusion As a short‐term effect, PDI decreases bFGF release of keratocytes in vitro. The altered secretion of these factors may play a role in the activation of keratocytes following PDI.