Abstract
Purpose:
Crosslinking (CXL)/riboflavin-UVA photodynamic therapy (PDT) is a treatment option to stop the progression of keratoconus. Growth factors and interleukins have the function to regulate proliferation and motility of the cells and even wound healing. The purpose of this study was to determine the impact of crosslinking on growth factor and interleukin secretion of human keratoconus keratocytes, in vitro.
Methods:
Primary human keratoconus keratocytes were isolated by digestion in collagenase (1 mg/ml) from human corneal buttons, and cultured in DMEM/Ham's F12 medium supplemented with 10% FCS. Keratocyte cell cultures underwent UVA illumination using light (370 nm) for 4.10 minutes during exposure to 0.1% riboflavin and 20% dextran containing PBS. Five and twenty-four hours after CXL, secretion of FGFb, HGF, TGFβ1, VEGF, KGF, IL-1β, IL-6, and IL-8 was measured by enzyme-linked-immunoabsorbent assay ( ELISA).
Results:
KGF and IL-1β secretion of keratocytes was below the measurement limit for all time points. Using riboflavin or UVA light illumination separately, growth factor and interleukin secretion of keratocytes remained unchanged for both time points (p>0.35). Five hours after crosslinking, FGFb secretion of keratoconus keratocytes increased significantly (p = 0.037) compared to untreated controls, whereas HGF, TGFβ1, VEGF, IL-6, and IL-8 secretion remained unchanged. Twenty-four hours following CXL, none of the growth factor and interleukin concentrations differed significantly from untreated controls (p>0.15).
Conclusions:
Crosslinking triggers FGFb secretion of keratoconus keratocytes transiently (five hours), which normalizes after 24 hours. Crosslinking does not have an impact on HGF, TGFβ1, VEGF, KGF, IL-1β, IL-6, and IL-8 secretion of keratoconus keratocytes in the short-term.
Keywords: 574 keratoconus •
647 photodynamic therapy •
490 cytokines/chemokines