Comparison of tear proteomic and neuromediator profiles changes between small incision lenticule extraction (SMILE) and femtosecond laser-assisted in-situ keratomileusis (LASIK)

Abstract

Introduction: The tear proteomics and neuromediators are associated with clinical dry eye parameters following refractive surgery.

Purpose: To investigate and compare the tear proteomic and neuromediator profiles following small incision lenticule extraction (SMILE) versus laser-assisted in-situ keratomileusis (LASIK).

Methods: In this randomized controlled trial with paired-eye design, 70 patients were randomized to receive SMILE in one eye and LASIK in the other eye. Tear samples were collected preoperatively, and 1 week, 1, 3, 6 and 12 months postoperatively, and were examined for protein concentration changes using sequential window acquisition of all theoretical fragment ion mass spectrometry (SWATH-MS). The data were analyzed with DAVID Bioinformatics Resources for enriched gene ontology terms and over-represented pathways. Tear neuromediators levels were correlated with clinical parameters.

Results: Post-SMILE eyes had significantly better Oxford staining scores and tear break-up time (TBUT) than post-LASIK eyes at 1 and 3 months, respectively. Tear substance P and nerve growth factor levels were significantly higher in the LASIK group for 3 months and 1 year, respectively. SMILE and LASIK shared some similar biological responses postoperatively, but there was significant up-regulation in leukocyte migration and wound healing at 1 week, humoral immune response and apoptosis at 1 month, negative regulation of endopeptidase activity at 3 to 6 months, and extracellular structure organization at 1 year in the post-LASIK eyes. Tear mucin-like protein 1 and substance P levels were significantly correlated with TBUT (r = -0.47, r = -0.49, respectively).

Conclusion: Significant differences in the tear neuromediators and proteomics were observed between SMILE and LASIK, even though clinical dry eye signs have subsided and became comparable between 2 procedures.

Keywords: Dry eye; Laser-assisted in-situ keratomileusis; Neuromediators; Proteomics; Small incision lenticule extraction; Tear.

Graphical abstract

Fig. 1

Volcano plot showing the fold changes and p values comparing the proteomic data of different postoperative time points (A: 1 week, B: 1 month, C: 3 months, D: 6 months, E: 12 months) with that of baseline in SMILE. Red dots indicate significantly up-regulated proteins (FC > 1.5 and P < 0.05, i.e. log₂ FC > 0.58 and -log₂P > 4.3), and blue dots indicate significantly down-regulated proteins (FC < 0.67 and P < 0.05, i.e. log₂ FC < -0.58 and -log₂P > 4.3).

Fig. 2

Chord plots illustrating GO analysis of top 10 up-regulated and down-regulated proteins and associated pathways in SMILE surgery at 1 week (A), 1 month (B), 3 months (C) and 12 months (D), in comparison to the baseline. Chord plots represent a circular dendrogram of the clustering of the expression profiles. Log FC: log₂ (fold-changes).

Fig. 3

Volcano plot presenting the fold changes and p values comparing the proteomic data of different postoperative time points (A: 1 week, B: 1 month, C: 3 months, D: 6 months, E: 12 months) with that of baseline in LASIK. Red dots indicate significantly up-regulated proteins (FC > 1.5 and P < 0.05, i.e. log₂ FC > 0.58 and -log₂P > 4.3), and blue dots indicate significantly down-regulated proteins (FC < 0.67 and P < 0.05, i.e. log₂ FC < -0.58 and -log₂P > 4.3).

Fig. 4

Chord plots demonstrating GO analysis of top 10 up-regulated and down-regulated proteins in LASIK procedure when comparing the profiles at 1 week (A), 1 month (B), 3 months (C) and 12 months (D) to those of the baseline. Chord plots represent a circular dendrogram of the clustering of the expression profiles. Log FC: log₂ (fold-changes).

Fig. 5

Volcano plot presenting the fold changes and p values comparing the proteomic data between LASIK and SMILE at different time points (A: before surgery, B: 1 week, C: 1 month, D: 3 months, E: 6 months, F: 12 months). Red dots indicate significantly up-regulated proteins (FC > 1.5 and P < 0.05, i.e. log₂ FC > 0.58 and -log₂P > 4.3) and blue dots indicate significantly down-regulated proteins (FC < 0.67 and P < 0.05, i.e. log₂ FC < -0.58 and -log₂P > 4.3). Tear proteomic profiles were comparable between LASIK and SMILE group before surgery (A).

Fig. 6

Chord plots demonstrating GO analysis of top 10 up-regulated and down-regulated protein profiles when comparing LASIK versus SMILE procedure at 1 week (A), 1 month (B), 3 months (C) and 12 months (D). Chord plots show the clustering of the expression profiles. Log FC: log₂ (fold-changes).