Secretory Phospholipase A2Deposition on Contact Lenses and Its Effect on Bacterial Adhesion

Emma B. H. Hume, Nerida Cole, Alpesh Parmar, Maxine E. Tan, Yulina Aliwarga, Tracey Schubert, Brien A. Holden, Mark D. P. Willcox
2004 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
more » ... 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.
doi:10.1167/iovs.03-1242 pmid:15326135 fatcat:73c5zkuskbh23m7gdxbmpxw32y