Date Published: February 2, 2017
Publisher: Public Library of Science
Author(s): Chien-Jung Huang, Yi-Chen Sun, Karen Christopher, Amy Shih-I Pai, Chia-Ju Lu, Fung-Rong Hu, Szu-Yuan Lin, Wei-Li Chen, Alexander V. Ljubimov.
To evaluate the corneal epitheliotropic abilities of two commercialized human platelet lysates (HPLs) and to compare the results with other blood derivatives, including human peripheral serum (HPS) and bovine fetal serum (FBS).
In vitro, human corneal epithelial cells were incubated in various concentrations (0%, 3%, 5% and 10%) of blood derivatives. Two commercialized HPLs, including UltraGRO TM (Helios, Atlanta, GA) and PLTMax (Mill Creek, Rochester, MI), were tested and compared with HPS and FBS. Scratch-induced directional wounding assay was performed to evaluate cellular migration. MTS assay was used to evaluate cellular proliferation. Cellular differentiation was examined by scanning electron microscopy, inverted microscopy and transepithelial electrical resistance. Sprague-Dawley rats were used to evaluate the effects of the blood derivatives on corneal epithelial wound healing in vivo. Different blood derivatives were applied topically every 2 hours for 2 days after corneal epithelial debridement. The concentrations of epidermal growth factor (EGF), transforming growth factor -β1 (TGF-β1), fibronectin, platelet-derived growth factor-AB (PDGF-AB), PDGF-BB, and hyaluronic acid in different blood derivatives were evaluated by enzyme-linked immunosorbent assay (ELISA).
In vitro experiments demonstrated statistically comparable epitheliotropic characteristics in cellular proliferation, migration, and differentiation for the two commercialized HPLs compared to FBS and HPS. Cells cultured without any serum were used as control group. The epitheliotropic capacities were statistically higher in the two commercialized HPLs compared to the control group (p<0.05). Among the different concentrations of blood derivatives, the preparations with 3% yielded better outcomes compared to 5% and 10%. In rats, HPLs also caused improved but not statistically significant wound healing compared to HPS. All the blood derivatives had better wound healing ratios than the control group (p<0.05). In the quantification of epitheliotropic factors, UltraGRO and PLTMax had significantly higher levels of EGF, TGF- β1, fibronectin than human peripheral serum (p<0.05). Both commercialized HPLs showed comparable corneal epitheliotropic abilities and wound healing rates compared to HPS and FBS in the in vivo and in vitro studies. Our results suggest that HPLs may have the potential to replace HPS in the treatment of corneal epithelial problems.
Human peripheral serum (HPS) has long been used as a topical treatment for ocular surface disorders such as recurrent corneal erosions, persistent epithelial defects, superior limbic keratoconjunctivitis, and dry eye syndrome. [1–13] However, HPS has several major disadvantages. The process of obtaining peripheral blood from the patients and processing this to serum eye drops may be inconvenient for clinical application. The quality of HPS may be inconsistent, especially in patients with poor health, and the epitheliotropic abilities may be unsatisfactory or unpredictable. No standardized dilution protocol has been reported. HPS contains proinflammatory agents such as matrix metalloproteinase (MMP) and acid hydrolase that are derived from leukocyte degranulation and may induce unwanted side effects. [14, 15] In addition, HPS can be inconvenient for the patient due to its need to be stored at -4°C and be used preferably within a week. 
In this study, we demonstrated two different commercialized HPLs with corneal epitheliotropic capacities not inferior to that of HPS both in vivo and in vitro. Commercialized HPLs had significantly higher concentrations of several important growth factors, such as EGF, TGF-β1, PDGF-AB and PDGF-BB, compared to HPS. As far as we know, this is the first study to evaluate commercialized HPLs and to compare their corneal epitheliotropic properties with those of other blood derivatives. We believed these two HPLs have the potential to be used as topical eye drops for facilitating corneal re-epithelialization and to replace blood derivatives like HPS.