Abstract
Abstract: :
Purpose: Thymosin beta 4 (Tß4) is a naturally occurring low molecular weight peptide with multiple biologic properties. Tß4 been implicated in endothelial cell migration, chemotaxis, angiogenesis, inhibition of inflammation, and wound healing. Most recently Sosne et al (Exp. Eye Res. 2002,24:268-273) have reported that Tß4 accelerates the healing of the cornea following heptanol or alkali injury and to increase cell-cell and cell-matrix remodeling. The spectrum of ocular roles of Tß4 is rapidly expanding, though precise mechanisms of these properties at cellular levels are still unknown. Because Tß4 has effects on corneal wound healing and re-epithelialization, and is a known anti-inflammatory agent, we sought to determine whether it is naturally occurring in human tears. Methods: We analyzed human tears for the presence of this small 43 amino acid 4.9kDa protein. Ten samples were collected from each of three patient age groups: 20-30, 45-55, and >60 years old (n=30). Exclusion criteria included the use of any topical ophthalmic medications and/or history of ocular surgery within the past six months. Tears were collected from both eyes using Schirmer’s strips. Samples were analyzed by ELISA to identify and to quantify the amount of Tß4 present in tears. Results: Tß4 was found in all tear samples in all age groups. The concentrations ranged from 1ug/ml to 7 ug/ml. Studies are currently in progress to define changes in Tß4 levels with age and disease states. Conclusions: This is the first study to show the presence of Tß4 within human tears. The presence of Tß4 in tears raises the possibility of its role in human ocular surface disease and modulation. Studies have demonstrated Tß4 to be a potent agent facilitating corneal wound healing following trauma. It is a known agent that facilitates re-epithelialization. Given that Tß4 modulates anti-inflammatory mediators, the ocular effects of Tß4 are likely of practical clinical significance; moreover, the possibility of employing exogenous Tß4 as a therapeutic agent in ocular surface disease and injury deserves serious study.
Keywords: wound healing • cornea: tears/tear film/dry eye • cornea: basic science