Local proteolytic system indicators as suspective factors of keratolysis development after urgent keratoplasty

Purpose: to determine the concentration of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in the tear of patients with cornea melting and to assess whether these factors can be used as prognostically significant biomarkers of keratolysis. Material and methods. 20 patients who underwent urgent penetrating keratoplasty were tested for cornea perforation (melting) before and after the procedure. For control, 12 healthy adults (24 eyes) were tested. The tear fluid was collected before the surgery and on the 7th day after it with the help of filtering paper. MMP-9 and TIMP-1 concentrations were determined by ELISA. The course of the early postoperative period was assessed according to the area of keratotransplant epithelization on the 7th day after surgery. Results. MMP-9 and TIMP-1 concentrations in the tears of all patients before the surgery were significantly higher than the ones of healthy controls. The patients who were supposed to have re-keratoplasty had a significantly higher MMP-9 concentration than the ones who expected the first keratoplasty. An uncomplicated early postoperative period showed a statistically significant decrease of MMP-9 and TIMP-1 concentrations, whilst the complicated one demonstrated a significant increase of both markers. The highest increase of both markers was shown by the patients who underwent re-keratoplasty. Conclusion. MMP-9 concentration in the tears is a valid marker of the clinical course of the early post-keratoplasty period. To ensure a successful donor cornea engraftment, the levels of MMP-9 and TIMP-1 in the tear must be high enough before the surgery and the concentration of the ferment should decrease timely after its main functions have been completed. A 2-fold (or greater) decrease of MMP-9 concentration in the tear on the 7th day after keratoplasty can be considered a marker of the favorable prognosis for engraftment.