title: Preservation of human tear protein structure and function by a novel contact lens multipurpose solution containing protein-stabilizing agents.
abstract: OBJECTIVE
  Tear film proteins have antimicrobial and other functions that may be lost after denaturation during contact lens wear. A new multipurpose solution has recently become available (Biotrue, Bausch + Lomb Inc., Rochester, NY), which contains protein-stabilizing agents including hyaluronic acid, poloxamine, and sulfobetaine 10, the latter used previously as a laboratory tool to renature proteins. We examine whether this new multipurpose solution formulation can prevent the denaturation of human lactoferrin and lysozyme at physiologic levels in response to a powerful denaturing challenge.
  
  
  METHODS
  Human lactoferrin and lysozyme were treated with sodium dodecyl sulfate (SDS) either with or without an investigational version of the new multipurpose solution (without its two disinfectant agents) (investigational multipurpose solution [iMPS]). The structure was assessed by native-polyacrylamide gel electrophoresis (PAGE), differential scanning calorimetry (DSC), and fluorometry; additionally, antimicrobial activity against Pseudomonas aeruginosa and Staphylococcus aureus was measured.
  
  
  RESULTS
  The iMPS prevented an SDS-induced shift in the native-PAGE banding position of lactoferrin. The SDS treatment substantially altered the lactoferrin DSC and fluorescence spectra, indicating that the protein had denatured. This change did not occur in the presence of iMPS. Lactoferrin and lysozyme showed antibacterial and bacteriolytic activity, which was abolished after SDS treatment; this loss of activity did not occur for proteins treated with iMPS.
  
  
  CONCLUSIONS
  These data clearly show that the iMPS prevents the denaturation of physiologic levels of human lactoferrin and lysozyme by the strongly denaturing surfactant SDS and that stabilized proteins retain their function. We conclude that this solution has the capacity to stabilize the structure and function of tear proteins.
authors.affiliation: Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom.
authors.forename: Elli A
authors.initials: EA
authors.lastname: Wright
authors.forename: Karl A P
authors.initials: KA
authors.lastname: Payne
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Jowitt
authors.forename: Marjorie
authors.initials: M
authors.lastname: Howard
authors.forename: Philip B
authors.initials: PB
authors.lastname: Morgan
authors.forename: Carole
authors.initials: C
authors.lastname: Maldonado-Codina
authors.forename: Curtis B
authors.initials: CB
authors.lastname: Dobson
mesh_terms: D000704:Analysis of Variance; D015169:Colony Count, Microbial; D018639:Contact Lens Solutions / Q000737:chemistry* / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D005136:Eye Proteins / Q000737:chemistry* / Q000187:drug effects; D006801:Humans; D007781:Lactoferrin / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D009113:Muramidase / Q000737:chemistry*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000254:growth & development; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development
chemical_list: D018639:Contact Lens Solutions; D005136:Eye Proteins; C042434:tear proteins; D012967:Sodium Dodecyl Sulfate; D009113:Muramidase; D007781:Lactoferrin