LACRIMAL SECRETION OF HUMAN EPIDERMAL GROWTH-FACTOR IN PERFORATING KERATOPLASTY

Human epidermal growth factor (hEGF) plays a key role in the regulatio n of corneal epithelial regeneration. As the lacrimal concentration of EGF is known to decrease following corneal injury, therapeutic applic ation of exogenic EGF to support corneal wound healing is currently be ing investigated, To evaluate the role of topical EGF substitution in perforating keratoplasty, the lacrimal secretion of EGF was determined in 12 patients prior to keratoplasty and on the Ist and 7th days post operatively using a newly developed modular immunofluorometric assay. EGF secretion and tear-flow rates in the tear samples of the keratopla sty patients were compared with those of 39 patients with corneal epit helial defects of other origin and those of 21 healthy controls. Level s of EGF secretion and tear flow reflectorily increased both in the po stoperative samples of keratoplasty patients (secretion 0.77+/-0.56 pg /s. tear flow 18.7+/-14.9 mu l/min) and in the samples of patients wit h corneal epithelial defects (0.6+/-0.4 pg/s, 19.6+/-19.2 mu l/min) in comparison with preoperative values and healthy controls (0.3+/-0.2 p g/s, 4.0+/-5.4 mu l/min), Men showed higher average levels of basal an d reflectory EGF secretion (0.4 and 0.8 pg/s), respectively than did w omen (0.25 and 0.55 pg/s, respectively). The results indicate a physio logical feedback mechanism that reflectorily adjusts the lacrimal EGF secretion following corneal irritation. Topical therapy with recombina nt EGF should therefore be restricted to patients with persistent corn eal epithelial defects and proven deficiency of EGF secretion.