Cytokine secretion of human keratocytes following crosslinking / riboflavin-UVA photodynamic inactivati on ( PDI ) , in vitro

Crosslinking/Riboflavin-UVA photodynamic inactivati on (PDI) is a potential treatment option in keratoc onus and in therapy resistant infectious keratitis. We aimed to evaluate the impact of crosslinking/riboflavin-UVA -PDI on TGFβ1, FGFb, VEGF, HGF, KGF, IL-6 and IL-8 secretion of normal human keratocytes, in vitro. Primary human keratocytes were isolated by digestion in collagena s (1.0 mg/ml) from human corneal buttons, and cult ured in DMEM/Ham's F12 medium supplemented with 10% FCS. Ce ll cultures underwent UVA-light illumination (8.0 mW/cm) for 4.10 minutes during exposure to 0.1% concentr ation of riboflavin-5-phosphat. Five and 24 hours a fter crosslinking, cytokine concentration was determined in the cultur e supernatant using ELISA. Five hours after riboflavin-UVA-PDI, FGFb, VEGF and HGF secretion of keratocytes decreased significantly (p<0.01; p<0.0 5; p<0.01) and TGFβ1, IL-6 and IL-8 secretion remained unchanged. Twen ty-four hours following riboflavin-UVA-PDI, FGFb and KGF secretion decrease d (p<0.01; p<0.01) and IL-6 secretion increased significantly (p<0.01), whereas TGF β1, VEGF and HGF secretion remained unchanged. Crosslinking/riboflavin-UVA-PDI decreases FGFb, VEG F and HGF secretion 5 hours and FGFb and KGF secretion 24 hours after treatment, while it increa s s IL-6 secretion of keratocytes after 24 hours. I n the short term, riboflavin-UVA-PDI does not have an impact on TGF β1 and IL-8 secretion of keratocytes, in vitro.