Effects of multipurpose contact lens care solutions on the adhesiveness of Acanthamoeba to corneal epithelial cells.
OBJECTIVE
To study the adhesion of Acanthamoeba castellanii treated with multipurpose contact lens care solutions (MPSs) to human corneal epithelial cells.


METHODS
Cell suspensions of A. castellanii (ATCC50514) trophozoites were mixed with six MPSs: MPS-A (polyhexamethylene biguanide [PHMB], macrogolglycerol hydroxystearate, propylene glycol), MPS-B (PHMB, poloxamine, boric acid), MPS-C (polyquad, poloxamine, boric acid), MPS-D (PHMB, poloxamer, propylene glycol), MPS-E (PHMB, poloxamer), or MPS-F (PHMB, poloxamer) for 4 hr. Morphologic changes of A. castellanii after exposure with MPSs were observed with scanning electron microscopy. A. castellanii cells treated with MPS for 4 hr were inoculated onto cultured SV40-immortalized human corneal epithelial cells. After 2-hr incubation, the number of adherent A. castellanii was assessed by 18S-rDNA quantification using real-time polymer chain reaction.


RESULTS
After 4-hr incubation, MPS-A- and MPS-B-treated A. castellanii have changed from trophozoite morphology into cyst form; however, MPS-E- and MPS-F-treated A. castellanii maintained trophozoite morphology. In contrast, both cyst and trophozoite forms were observed in MPS-C- and MPS-D-treated A. castellanii. The adherence rate of A. castellanii was approximately two times higher in MPS-E (not significant), and more than three times higher in MPS-F (P<0.05) compared with MPS-A, which produced the lowest adhesiveness as estimated by real-time polymer chain reaction.


CONCLUSIONS
Taken together, these results support the possibility that chronic use of MPS with the lowest efficacies on promoting encystment of A. castellanii (MPS-E and MPS-F) by hydrogel contact lens wearers may increase adhesiveness of A. castellanii to corneal epithelial cells.
Imayasu
Masaki
M
Menicon Co., Ltd., Kasugai, Aichi, Japan. imayasu-m@menicon-net.co.jp
Uno
Toshihiko
T
Ohashi
Yuichi
Y
Cavanagh
H Dwight
HD
D000048:Acanthamoeba / Q000187:drug effects* / Q000502:physiology* / Q000648:ultrastructure; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002461:Cell Line, Transformed; D018639:Contact Lens Solutions / Q000494:pharmacology*; D019573:Epithelium, Corneal / Q000166:cytology / Q000469:parasitology*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D013997:Time Factors; D053058:Trophozoites / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure
D018639:Contact Lens Solutions