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Walter L. Nash, Michael S. Foster, Manal M. Gabriel, Alan Landers; The Correlation between Loosely Adherent sPLA2IIA in Symptomatic and Asymptomatic Non-Ionic Silicone Hydrogel Lens Wearers. Invest. Ophthalmol. Vis. Sci. 2012;53(14):4703.
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To evaluate the difference in the levels of secretory phospholipase A2 Type IIA (sPLA2IIA) in the tear envelope collected from symptomatic (i.e. reports decreased comfort at replacement time) and asymptomatic patients.
In this study, lenses were collected from the symptomatic and asymptomatic patients aseptically and stored dry at below -20 ºC. All patients wore the same non-ionic silicone hydrogel lens material and used the same lens care regimen. Lenses were equilibrated to ambient temperature and rinsed in 2 mL of phosphate buffered saline for 5 minutes with agitation. The rinsate from each lens was subjected to a sandwich ELISA by introduction to a plate coated with a monoclonal antibody specific for sPLA2IIA. The plate was washed and an Acetylcholinesterase (ACHe); Fab’conjugate was added to the plate which selectively binds to a different epitope on the sPLA2IIA molecule. Finally, the enzymatic activity of ACHe was measured by adding a reagent containing the ACHe substrate and reading the plate at a wavelength of 420 nm by spectrophotometry.
Symptomatic and asymptomatic patients exhibited statistically similar levels of sPLA2IIA in the tear envelop of 22.6±10.8 and 20.7±7.8 ng/Lens, respectively (p = 0.413) (student’s t-test, α = 0.05).
sPLA2IIA is known to hydrolyze fatty acids generating free arachidonic acid and lysophospholipids, the precursors of pro-inflammatory lipid mediators. Recent studies have reported elevated levels of sPLA2IIA in the tears of intolerant contact lens wearers and increased sPLA2IIA activity in tears from dry eye disease patients. Our findings, which focused on comfort at replacement time, suggest that there is no difference in the levels of sPLA2IIA in the tear envelope between symptomatic and asymptomatic patients as defined by the criteria of this study. However, it is possible that the relationship between comfort and sPLA2IIA levels is multi-factorial and therefore, future efforts should be in evaluating the interdependence with other biomarkers.
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