Abstract
Abstract: :
Purpose:Serum eyedrops have successfully been used to treat ocular surface disorders such as dry eyes or persistent epithelial defects. Their beneficial effect is thought to result from a variety of growth factors present in serum. Platelets are a major source of growth factors in serum. They are available at adjustable concentrations in platelet rich suspensions from blood banks and – following stimulation with thrombin – release their growth factor content. We compared the capacity of platelet lysate versus serum to support proliferation, migration and differentiation of corneal epithelial cells in–vitro. Methods:Platelet concentrates with 4 x 109 thrombocytes / ml and serum were obtained from 10 healthy donors and prepared under standardised clotting and centrifugation conditions. In these samples EGF, HGF, FGF PDGF, TGF–ß, fibronectin, as well as vitamin A and E were quantified by means of routine ELISA– or HPLC–technology. SV–40 immortalised human corneal epithelial cells were cultured in 96–well plates at 37°C, 5% CO2 with a fully defined culture medium. At 30% confluency the culture medium was substituted by one of the test preparations. Proliferation of cell cultures was quantified by means of a luminescence–based ATP–assay in dose–response experiments. A colony dispersion assay was used to examine the effect on cell migration and differentiation was assessed by means of scanning electron microscopy. Results:Platelet lysates contained significantly higher amounts of EGF, FGF, PDGF and TGF–ß, but less HGF, fibronectin and vitamins than serum. Platelet lysates supported the proliferation of human corneal epithelial cells significantly better than serum, but migration was significantly better supported by serum. Both effects were dose–dependent. On scanning electron microscopy cells incubated with serum showed a confluent monolayer of adult epithelial cells, while platelet lysate induced activation of the cells. Conclusions:Thrombocyte concentrates can be used as a source for the production of an autologous, blood derived suspension rich in growth factors, but with little fibronectin and vitamins. Compared with serum the concentration of growth factors in platelet lysates can be adjusted to significantly higher levels of EGF, FGF, PDGF and TGF–b. This blood product supports proliferation, but not migration. It may offer a new treatment modality for ocular surface disorders.
Keywords: cornea: epithelium • nutritional factors • cornea: clinical science