title: Contact lens materials, mucin fragmentation and relation to symptoms.
abstract: OBJECTIVE
  Mucins adhere to contact lenses (CLs), reflecting the renewal of the preocular fluid and enzymatic activity at the ocular surface. In this study, we aimed to analyze mucin fragmentation on materials new to the ocular surface and investigate whether this correlates with wearing comfort.
  
  
  METHODS
  Lenses were obtained from new CL wearers after 2 weeks each of wearing vifilcon A, followed by senofilcon A, and then by vifilcon A lenses. Symptoms were evaluated using the Ocular Surface Disease Index (OSDI). CLs were extracted in a mixture of guanidinium hydrochloride and radioimmunoprecipitation assay buffer. Mucin mobility was analyzed after electrophoresis, Western blotting, and visualization with antibodies against mucin peptide core. Mobilities, normalized to total reactivity in the lane, were compared between visits for each subject and were expressed as shifts.
  
  
  RESULTS
  Mucin (MUC)5AC polymers exceeding 260 kDa were observed in agarose gels; NuPAGE resolved polymers from 260 to 3.5 kDa: when large mucins were detected, the smallest fragments were missing. Fragmentation patterns were significantly different between lens types for MUC1 (analysis of variance, P = 0.006) and MUC4 (P < 0.001) but not for MUC5AC or MUC16 (P > 0.293). Mobility shifts of MUC1 and MUC4 were significantly negatively correlated (Pearson, r = -0.908; P = 0.002). For OSDI scores >15, mucin fragmentation was unchanged, whereas for OSDI scores <15, MUC4 and MUC5AC fragments were longer on vifilcon A than on senofilcon lenses (unpaired t test, P = 0.046), irrespective of the direction of change (analysis of variance, P > 0.366). Changes in MUC1 breakdown were significantly negatively correlated to the overall OSDI score (r = -0.891, P = 0.001).
  
  
  CONCLUSIONS
  In asymptomatic CL wearers, only changes in mucin fragmentation in response to a new material were consistent and fast, irrespective of CL order. Lack of change seems, therefore, to be connected with discomfort during CL wear.
authors.affiliation: Academic Unit of Ophthalmology, University of Bristol, Bristol Eye Hospital, Bristol, United Kingdom.
authors.forename: Monica
authors.initials: M
authors.lastname: Berry
authors.forename: Chris
authors.initials: C
authors.lastname: Purslow
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Murphy
authors.forename: Heiko
authors.initials: H
authors.lastname: Pult
mesh_terms: D000328:Adult; D001672:Biocompatible Materials / Q000737:chemistry*; D015153:Blotting, Western; D003263:Contact Lenses, Hydrophilic; D004591:Electrophoresis, Polyacrylamide Gel; D005136:Eye Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D020100:Hydrogels / Q000737:chemistry; D008297:Male; D008970:Molecular Weight; D055271:Mucin 5AC / Q000378:metabolism*; D018396:Mucin-1 / Q000378:metabolism*; D055264:Mucin-4 / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011446:Prospective Studies; D017755:Prosthesis Fitting; D011485:Protein Binding; D015531:Radioimmunoprecipitation Assay; D012828:Silicones / Q000737:chemistry; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D001672:Biocompatible Materials; D005136:Eye Proteins; D020100:Hydrogels; C060192:MUC1 protein, human; C524658:MUC4 protein, human; C524678:MUC5AC protein, human; D055271:Mucin 5AC; D018396:Mucin-1; D055264:Mucin-4; D010446:Peptide Fragments; D012828:Silicones; C523196:senofilcon A; C042434:tear proteins