Epidermal growth factor (EGF) is a mitogenic polypeptide, which was first isolated from mouse submaxillary gland. Since EGF also stimulates the growth of corneal epithelial cells and only preliminary data exist on its presence in tear fluid, we studied the occurrence of human EGF (hEGF) in the tear fluid of 36 healthy persons (31 women and 5 men from 20 to 59 years of age; 60 eyes). hEGF, as measured by an immunofluorometric assay, was present in all tear fluid samples investigated. Its concentration varied from 200 to 2860 pg/ml (median, 705 pg/ml). The tear fluid hEGF concentrations differed less between the eyes of one individual than between individuals. The total amount of hEGF released to the tear fluid increased with fluid flow, but the higher the flow was, the lower the concentration of hEGF. We could not find any evidence of sex dependency in the hEGF concentrations. In demonstrating that hEGF is a normal component of human tear fluid, the results of this study suggest that hEGF may be important for conjunctival and corneal epithelial integrity.

Ulcerative keratitis in horses is associated with initially high levels of tear film proteolytic activity that decrease as the ulcers heal. The success of medical and surgical treatment of the corneal ulcers is reflected by the enzyme activity in tears. In horses successful treatment does lead to a rapid reduction in tear film proteolytic activity that corresponded with the improvement in the clinical signs of corneal ulceration. Measurement of MMP activity in the tear film might represent a way to monitor the progression of corneal healing in horses with ulcerative keratitis.

Hyaluronic acid (HA) ophthalmic solution is widely used in dry eye treatment worldwide. However, there are no reports comparing the dry eye treatment effects of high molecular weight HA with low molecular weight HA. Sixty eight-week-old C57BL/6 mice were assigned to the following 6 groups and exposed to environmental dry eye stress (EDES) that mimics office work environment: (1) 0.1% low molecular weight HA (LMWHA) eye drops, (2) 0.3% LMWHA eye drops, (3) 3% diquafosol sodium (DQ) eye drops, (4) 0.15% high molecular weight HA (HMWHA) eye drops, (5) no treatment with exposure to EDES (EDES+/Treatment−), and (6) no treatment without exposure to EDES (EDES−/Treatment−). After EDES, the HMWHA group had significantly longer break-up time (BUT) than the 0.1%, 0.3% LMWHA groups and the DQ group. After EDES, the HMWHA group had significantly lower lissamine green staining scores than the LMWHA and DQ groups. Subepithelial presumed dendritic cell density in the HMWHA group was significantly lower than the EDES+/Treatment− group. After EDES exposure, Conjunctival Muc5AC mRNA expression in the HMWHA group was significantly higher than the 0.1 and 0.3% LMWHA groups. Ophthalmic HMWHA solution may have a better dry eye treatment effect than LMWHA or DQ solution, owing to its anti-inflammatory effect.

Purpose: Connective tissue growth factor (CTGF) has been shown to be substantially involved in various processes of fibrosis. We investigated if CTGF is present in aqueous humor (AH). Methods: Samples from AH were collected from 10 volunteers during cataract surgery. Specific ELISA analysis was performed with goat IGG against human CTGF. Results: CTGF was above the detection limit of the assay in 80% of the samples. The concentration of CTGF in the anterior chamber fluid was 1.24 ± (SD) 0.26 ng/ml. Conclusion: CTGF is present in a majority of AH samples, possibly representing a constant component in this fluid. The origin and physiological importance of CTGF is yet unclear. The involvement of CTGF in processes of intraocular fibrosis and wound healing is possible.