Djuv Ane, Nilsen Odd Georg
Norwegian University of Science and Technology, Faculty of Medicine, Department of Cancer Research and Molecular Medicine, Trondheim, Norway.
Phytother Res. 2008 Dec;22(12):1623-8. doi: 10.1002/ptr.2536.
The aims of this study were to carry out a thorough quality control setup for essential Caco-2 cell characteristics in P-glycoprotein (P-gp) inhibition studies and to explore if Aloe vera juice (AVJ) inhibits the bidirectional transport of the P-gp substrate digoxin (30 nm). Seven AVJ concentrations (0.00001-1.0 mg/mL), anticipated to cover a clinically relevant range, were tested and digoxin apparent permeability coefficients (Papp), net Papp values (Papp(Net)) and net flux values (J(Net)) were calculated. Relevant validation parameters for P-gp inhibition studies in Caco-2 cells are suggested to include, as a minimum, an assay linearity test with and without a known P-gp inhibitor, cell cytotoxicity testing (MTT-test) for substrates and inhibitors, and cell integrity testing by TEER and mannitol transport measurements. The question is also raised whether a minimum effect of a reference P-gp inhibitor as verapamil should be demanded. Cell cytotoxicity was seen for digoxin at concentrations >or=3 microM and for AVJ at 10 mg/mL. AVJ did not inhibit the P-gp transport of digoxin in any of the concentrations tested. This indicates that AVJ is no inhibitor of the P-gp mediated transport of digoxin in vitro if AVJ is present in clinically relevant concentrations.
本研究的目的是为P-糖蛋白（P-gp）抑制研究中的关键Caco-2细胞特性建立全面的质量控制体系，并探究芦荟汁（AVJ）是否抑制P-gp底物地高辛（30 nM）的双向转运。测试了七种预期涵盖临床相关范围的AVJ浓度（0.00001 - 1.0 mg/mL），并计算了地高辛的表观渗透系数（Papp）、净Papp值（Papp(Net)）和净通量值（J(Net)）。建议Caco-2细胞中P-gp抑制研究的相关验证参数至少应包括：使用和不使用已知P-gp抑制剂的分析线性测试、底物和抑制剂的细胞毒性测试（MTT试验）以及通过跨上皮电阻（TEER）和甘露醇转运测量进行的细胞完整性测试。还提出了是否应要求维拉帕米等参考P-gp抑制剂产生最小效应的问题。地高辛在浓度≥3 μM时以及AVJ在10 mg/mL时可见细胞毒性。在所测试的任何浓度下，AVJ均未抑制地高辛的P-gp转运。这表明，如果AVJ以临床相关浓度存在，其在体外不是地高辛P-gp介导转运的抑制剂。
