title: Effects of lactoferrin on the viability and the encystment of Acanthamoeba trophozoites.
abstract: Lactoferrin (LF) is an iron-binding basic glycoprotein that has an antimicrobial effect against certain microbes. The purpose of this study is to evaluate the amoebicidal effect of bovine milk LF (bLF) against Acanthamoeba clinical-isolate trophozoites, which cause severe keratitis. Most of the risk factor for Acanthamoeba keratitis is from wearing soft contact lenses (SCLs). Acanthamoeba trophozoites were incubated in bovine LF (bLF) solution, and the ratios of viability and encystment were determined with microscopic analysis of cyst formation. The amoebicidal effect of bLF was assessed by Trypan blue assay. The ratios of viable cells in the presence of iron-free bLF (apo-bLF), native-bLF, and iron-saturated bLF (Fe-bLF) at the concentration of 10 μmol/L for 60 min were 7.7% ± 4.6%, 80.7% ± 10.1%, and 97.3% ± 1.5%, respectively. Apo-bLF showed potent amoebicidal effect against Acanthamoeba trophozoites, but Fe-bLF did not have this effect. After treating with apo-bLF, most dead cells were nonglobular forms of trophozoites but not cystic forms. Encystment of Acanthamoeba was assessed by the sarkosyl-calcofluor white assay. The encystment ratios treated with 0.5% propylene glycol (positive control) and 10 μmol/L apo-bLF for 24 h were 96.12% ± 10.6% and 0.47% ± 0.5%, respectively. These results suggest that the amoebicidal effect of apo-bLF without encystment might lead to the prevention of contamination of Acanthamoeba in SCL stock cases.
authors.affiliation: a Department of Life Science, Faculty of Agriculture, Tamagawa University, 6-1-1 Tamagawa-Gakuen, Machida, Tokyo 194-8610, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Tomita
authors.affiliation: b Central Research Laboratory, Menicon Co., Ltd., 5-1-10 Takamoridai, Kasugai, Aichi 487-0032, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Suzuki
authors.affiliation: a Department of Life Science, Faculty of Agriculture, Tamagawa University, 6-1-1 Tamagawa-Gakuen, Machida, Tokyo 194-8610, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Wada
authors.affiliation: b Central Research Laboratory, Menicon Co., Ltd., 5-1-10 Takamoridai, Kasugai, Aichi 487-0032, Japan.
authors.forename: Miya
authors.initials: M
authors.lastname: Nomachi
authors.affiliation: b Central Research Laboratory, Menicon Co., Ltd., 5-1-10 Takamoridai, Kasugai, Aichi 487-0032, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Imayasu
authors.affiliation: c Ophthalmology, JCHO Hoshigaoka Medical Center, 4-8-1 Hoshigaoka, Hirakata, Osaka 573-8511, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Araki-Sasaki
mesh_terms: D000048:Acanthamoeba / Q000187:drug effects* / Q000254:growth & development* / Q000472:pathogenicity; D015823:Acanthamoeba Keratitis / Q000188:drug therapy* / Q000469:parasitology; D000563:Amebicides / Q000494:pharmacology*; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002417:Cattle; D007781:Lactoferrin / Q000494:pharmacology*; D008892:Milk / Q000737:chemistry; D053058:Trophozoites / Q000187:drug effects*
chemical_list: D000563:Amebicides; D000890:Anti-Infective Agents; D007781:Lactoferrin
keywords: Acanthamoeba; amoebicidal effect; effet amoebicide; encystment; enkystement; lactoferrin; lactoferrine; trophozoite; trophozoïte