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

Tanja Stachon, Jiong Wang, Xuf


Crosslinking/Riboflavin-UVA photodynamic inactivation (PDI) is a potential treatment option in keratoconus 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 collagenase (1.0 mg/ml) from human corneal buttons, and cultured in DMEM/Ham's F12 medium supplemented with 10% FCS. Cell cultures underwent UVA-light illumination (8.0 mW/cm2) for 4.10 minutes during exposure to 0.1% concentration of riboflavin-5-phosphat. Five and 24 hours after crosslinking, cytokine concentration was determined in the culture supernatant using ELISA. Five hours after riboflavin-UVA-PDI, FGFb, VEGF and HGF secretion of keratocytes decreased significantly (p<0.01; p<0.05; p<0.01) and TGFβ1, IL-6 and IL-8 secretion remained unchanged. Twenty-four hours following riboflavin-UVA-PDI, FGFb and KGF secretion decreased (p<0.01; p<0.01) and IL-6 secretion increased significantly (p<0.01), whereas TGFβ1, VEGF and HGF secretion remained unchanged. Crosslinking/riboflavin-UVA-PDI decreases FGFb, VEGF and HGF secretion 5 hours and FGFb and KGF secretion 24 hours after treatment, while it increases IL-6 secretion of keratocytes after 24 hours. In the short term, riboflavin-UVA-PDI does not have an impact on TGFβ1 and IL-8 secretion of keratocytes, in vitro.

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