Ohio State University, Columbus, Ohio 43218-2342, USA.
Invest Ophthalmol Vis Sci. 2010 Jun;51(6):2949-54. doi: 10.1167/iovs.08-3368. Epub 2010 Jan 20.
The purpose of this work was to develop an enzymatic method of quantification of cholesterol and cholesterol esters derived from contact lenses, both in vitro and ex vivo.
Lotrafilcon B (O2 Optix; CIBA Vision, Inc., Duluth, GA) and galyfilcon A (Acuvue Advance; Vistakon, Inc., Jacksonville, FL) silicone hydrogel contact lenses were independently incubated in cholesterol oleate solutions varying in concentrations. After incubation, the lenses were removed and underwent two separate 2:1 chloroform-methanol extractions. After in vitro studies, 10 human subjects wore both lotrafilcon B and galyfilcon A contact lenses for 7 days. The lenses also underwent two separate 2:1 chloroform-methanol extractions. All in vitro and ex vivo samples were quantified with a cholesterol esterase enzymatic reaction.
Calibration curves from quantifications of in vitro contact lens samples soaked in successively decreasing concentrations of cholesterol oleate yielded coefficients of determination (R(2)) of 0.99 (lotrafilcon B) and 0.97 (galyfilcon A). For in vitro contact lens samples, galyfilcon A was associated with an average cholesterol oleate extraction of 39.85 +/- 48.65 microg/lens, whereas lotrafilcon B was associated with 5.86 +/- 3.36 microg/lens (P = 0.05) across both extractions and all incubation concentrations. For ex vivo contact lens samples, there was significantly more cholesterol and cholesterol esters deposited on galyfilcon A (5.77 +/- 1.87 microg/lens) than on lotrafilcon B (2.03 +/- 1.62 microg/lens; P = 0.0005).
This is an efficient and simple method of quantifying total cholesterol extracted from silicone hydrogel contact lenses and, potentially, the meibum and/or tear film. Certain silicone hydrogel materials demonstrate more affinity for cholesterol and its esters than do others.
本研究旨在开发一种酶法，用于定量分析接触镜中胆固醇和胆固醇酯，包括体外和体内实验。
分别将 Lotrafilcon B（O2 Optix；CIBA Vision，Inc.，佐治亚州德卢斯）和 Galyfilcon A（Acuvue Advance；Vistakon，Inc.，佛罗里达州杰克逊维尔）硅水凝胶接触镜浸泡在不同浓度的胆固醇油酸溶液中。孵育后，取出镜片并进行两次 2:1 的氯仿-甲醇萃取。在体外实验后，10 名志愿者佩戴 Lotrafilcon B 和 Galyfilcon A 接触镜 7 天。然后对镜片进行两次 2:1 的氯仿-甲醇萃取。所有体外和体内实验样本均采用胆固醇酯酶酶促反应进行定量。
对浸泡在浓度逐渐降低的胆固醇油酸溶液中的体外接触镜样本进行定量分析，得到的校准曲线的决定系数（R²）分别为 0.99（Lotrafilcon B）和 0.97（Galyfilcon A）。对于体外接触镜样本，Galyfilcon A 与平均 39.85 ± 48.65 µg/镜片的胆固醇油酸提取量相关，而 Lotrafilcon B 与 5.86 ± 3.36 µg/镜片相关（P = 0.05），这两种提取方法和所有孵育浓度下均是如此。对于体内接触镜样本，Galyfilcon A 上沉积的胆固醇和胆固醇酯明显多于 Lotrafilcon B（5.77 ± 1.87 µg/镜片比 2.03 ± 1.62 µg/镜片；P = 0.0005）。
这是一种从硅水凝胶接触镜中提取总胆固醇的高效、简单的定量方法，并且可能适用于睑板腺分泌物和/或泪膜。某些硅水凝胶材料对胆固醇及其酯的亲和力强于其他材料。
