Levels of the Novel Glycoprotein Lacritin in Human Tears After Laser Refractive Surgery

Lacritin is a naturally occurring tear protein with antimicrobial activity that is capable of stimulating mitogenesis in human corneal epithelial cells and promoting production of tears in lacrimal gland acinar cells. Heparanase (HPSE) acts as a regulator for lacritin by cleaving heparan sulfate chains and allowing lacritin to bind. We aim to measure both tear lacritin and HPSE pre- and post-operatively to elucidate lacritin and HPSE s response in patients undergoing PRK (photorefractive keratectomy) and LASIK (Laser-assisted in situ keratomileusis) with the possibility of the development of recombinant lacritin as a novel therapeutic agent for wound healing. Up to 196 patients eligible to undergo PRK or LASIK at the U.S. Army Warfighter Refractive Surgery Research Center at Fort Belvoir will be consecutively recruited: 98 PRK (49 male and 49 female) and 98 LASIK (49 male and 49 female). The purpose of this study is to measure tear lacritin and HPSE levels following surgery using a minimal risk procedure to collect tears from patients undergoing PRK or LASIK. Tears will be collected using a safe and established method that employs the use of a polyester fiber rod (Transorb Wick, Filtrona, Richmond, VA). The wicks will soak up tears from the inferior cul-de-sac of the left eye of each subject at the pre-operative visit and at 1 day, 1 week, 1, 3 and 6 months post-operatively to quantify tear lacritin and HPSE. Study design will allow for within subject comparison of lacritin and HPSE before and after surgery as well as comparison of responses between procedures (PRK vs. LASIK). The primary outcome measure is tear lacritin levels pre- and post-surgery. The secondary outcome is tear HPSE levels pre-and post-surgery.
The original document contains color images.