The previous experiments demonstrate that MMP9 levels are critically elevated in KC corneas and hence its inhibition by CyA (Restasis) might be a novel treatment modality. Since CyA is approved for treatment of dry eye, a small cohort of KC patients were treated with topical CyA with prior informed consent. The CyA treatment is currently a well established treatment modality for dry eye of inflammatory etiology as a potent immunomodulator.
36 Therefore, on the basis of a questionnaire detailing patient complaints of irritation, eye rubbing, or ocular surface pain (typical of inflammatory etiology), KC subjects were assigned to a treatment cohort for CyA. A total of 20 patients (27 eyes) were treated with a dose of 0.05% CyA (Restasis), 1 to 2 drops, two times daily, for approximately 6 months. Within this cohort of CyA-treated patients, tears were collected both before and after the end of treatment period for a total of 14 eyes (paired group). To analyze the MMP9 levels and topographic data in the remainder of the CyA-treated group, we used the data from the previous cohort in
Figure 2 as the no-treatment group (unpaired group). The data in
Figures 5A and
5B demonstrate that CyA-treated cohort demonstrated a reduction in tear MMP9 levels compared with the negative controls. In the paired treatment group (tears available for both before and after CyA treatment for the same individual), there was a significant reduction in MMP9 levels. On evaluation of the topography of the subjects from this cohort of CyA treatment, we observed local changes in the corneas upon simulated keratometry at the end of last follow-up.
Figures 6A through
6F show axial curvature maps of the anterior corneal surface before and after application of CyA in left and right eyes of three patients, respectively. The areas where significant local flattening of the corneal curvature is observed are marked in the figure with red circles. The levels of MMP9 in tears of the patients collected at the time of corneal topography scans were also indicated. In Patient 1, there are pockets where axial curvature decreased, for example, 54.7 diopters (D; axis 270° inferior) reduced to 53.2 D (
Fig. 6A). Corresponding tear MMP9 levels reduced from 48.5 to 27.4 ng/mL in the same patient's eye. In
Figure 6D, the right eye of same subject (patient 1) as in
Figure 6A is presented and showed some reduction in curvature, for example, 52.3 D (axis 270° inferior) reduced to 51.2 D while tear MMP9 reduced from 38 to 33.5 ng/mL. Similarly, 49.8 D (axis 300 inferior-nasal) reduced to 48.5 D. In
Figure 6B (patient 2), 56.2 D (axis 210 inferior-nasal) reduced to 54.9 D. The tear MMP9 level reduced from 43 to 28.5 ng/mL in the same eye. Similarly in
Figure 6E (patient 2), the inferior cornea shows some decrease in curvature as well. Corresponding tear MMP9 levels reduced from 42 to 34.5 ng/mL in the same patient eye. Patient 3 (
Figs. 6C,
6F) showed similar remodeling and reduction in MMP9 as patient 1 and 2 while tear MMP9 levels also reduced as indicated. This data raises the possibility that corneal remodeling may be partly due to the reduction of MMP9 levels observed in these KC patients after CyA treatment. However, this local flattening was not evident in all patients, but disease progression was not observed over the 6-month period (
Supplementary Fig. S4) as demonstrated by mean keratometry and corneal thickness values (
Supplementary Table S2).