Secretory Phospholipase A2Deposition on Contact Lenses and Its Effect on Bacterial Adhesion
Investigative Ophthalmology and Visual Science
PURPOSE. Secretory phospholipase A 2 (sPLA 2 ) is a potent antibacterial enzyme in tears and has been found to kill Staphylococcus aureus rapidly in vitro. The purpose was to determine whether sPLA 2 deposition is associated with contact lens (CL) type, if sPLA 2 remains active on CLs, and if this has an effect on bacterial adhesion. METHODS. Ionic (etafilcon A) and nonionic (Polymacon) highwater, soft CLs were used. CLs were worn for 6 hours (daily wear, n ϭ 39) or 6 nights on an extended-wear
... on an extended-wear schedule (n ϭ 25). Tears were collected from patients and worn contact lenses were removed and protein and active enzymes extracted for estimation of their levels. The number of S. aureus adhering to sPLA 2 -soaked CLs in vitro was also quantified. RESULTS. There was no significant difference in the concentration of sPLA 2 in tears between groups of daily CL wearers. Significantly less sPLA 2 was recovered from Polymacon CLs for both daily and extended wear compared with etafilcon A CLs (daily wear: 3 vs. 5 ng/lens; extended wear: 3 vs. 6 ng/lens; P Ͻ 0.05). sPLA 2 activity correlated with protein amounts from lenses. Relatively less active sPLA 2 was recovered from Polymacon contact lenses. sPLA 2 reduced adhesion of Staphylococcus to contact lenses in vitro. CONCLUSIONS. Etafilcon A CLs absorb more active sPLA 2 than Polymacon CLs, which increases with length of CL wear. The sequestering of sPLA 2 onto CLs did not affect amounts of the enzyme in tears. sPLA 2 adsorbed to a CL can reduce the viable Staphylococcus adhering to the CL, which may protect the eye from colonization by this pathogen. (Invest Ophthalmol Vis Sci.