Tear film proteomics after LASIK surgery

Abstract

Purpose : LASIK surgery has shown to be efficient and safe technique to correct refractive errors. However, patients are reacting individually to the operation and this may cause many, even serious, adverse reactions. To analyse the individual reactions to LASIK surgery, tear proteomics were used and correlated with clinical variables.

Methods : LASIK procedure was carried out by using Ziemer FEMTO LDV Z6 I femtosecond laser and Wavelight EX500 excimer laser. Tear samples were collected preoperatively (V0) and at 1.5 hours (V1) and 1 month (V30) after LASIK treatment using glass microcapillary tubes. The samples were analysed with the NanoRPLC-tripleTOF method and protein quantitation analysis was performed by the SWATH method. R software and Ingenuity Pathway Analysis (IPA) were used for analyses.

Results : In total 747 proteins were identified and relatively quantified from 64 patients. The comparison of protein expression levels between V0 and V1 identified altogether 254 differentially expressed proteins (adjusted P < 0.05) and 148 proteins were identified for the V1-V30 comparison. Among the results, ALB (log2 fc=3.1, P<0.001) and ENO1 (log2 fc=1.4, P<0.001) were increased and YWHAB (log2 fc=-1.2, P<0.001) was decreased at V1 and the expression levels were then returned at V30 (ALB: log2 fc=-2.6, P<0.001, ENO1: log2 fc=-1.3, P<0.001, YWHAB: log2 fc=1.3, P=0.008). The pathway analyses showed that at V1, there is a rapid increase of proteins related to immune cell chemotaxis and decrease of proteins related to cell death. These actions are then reversed at V30, where chemotaxis of immune cells is decreased and cell death is increased. We also identified some statistically significant correlations between protein expression changes and clinical variables (preoperative UCVA (1 protein), postoperative BCVA (2 proteins), predictability (2 proteins) and optical zone (2 proteins)), which all had (abs.) rho>0.5 and adj. P<0.05. For example, for NUCB2 and LGALS3 expression level changes between V1-V30 were correlating with optical zone (mm), rho=-0.7, P<0.001 and rho=0.7, P<0.001 respectively.

Conclusions : LASIK surgery induced typical cell death and immune system reactions which returned to normal after 1 month and these could be seen in tear samples. The correlations between the clinical variables and proteomic changes could help us better understand their connections and in some cases evaluate the effects of LASIK surgery in proteomics and clinical variables.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.