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Study: Contact lenses can impede epithelial defense against corneal infection
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Contact lenses can interfere with the epithelial defense responses to bacterial antigens, according to a study by California researchers.
"Exposure of human corneal epithelial cells to contact lenses in vitro suppresses the upregulation of human ß-defensin-2 in response to antigens of Pseudomonas aeruginosa," the authors said.
Suzanne M.J. Fleiszig, OD, PhD, FAAO, and colleagues at the University of California exposed cultured epithelial cells to a hydrophilic contact lens for up to 3.5 days. They then exposed the cells to a culture supernatant of P. aeruginosa antigens for 6 hours, according to the study.
"Corneal epithelial cells express numerous innate defenses, some of which have bactericidal effects against P. aeruginosa. One of these is human ß-defensin-2 (hBD-2), which is upregulated in response to lipopolysaccharide or flagellin antigens," the authors said.
Without prior exposure to the contact lens, the supernatant caused more than a two-fold upregulation of the hBD-2 mRNA message and expression of the hBD-2 peptide. Prior lens exposure blocked this upregulation without causing any obvious effects on cell health, according to the study.
The researchers also observed that Pseudomonas-induced hBD-2 upregulation involved MyD88, c-Jun N-terminal kinase and both AP-1 and NF-kappa-B transcription factors. Exposure to the contact lenses did not affect the surface expression of the Toll-like receptors 2, 4 or 5, but did block the activation of antigen AP-1 transcription factors without blocking NF-kappa-B, they noted.
The study is published in the July issue of Experimental Eye Research.