Sharma A, Coles W H
Department of Ophthalmology, School of Medicine and Biomedical Sciences, State University of New York, Buffalo.
Invest Ophthalmol Vis Sci. 1989 Sep;30(9):1962-71.
We use a population balance model to study the mechanism and the rate of centripetal migration of epithelial cells, renewal of the corneal epithelial population by the cell derived from (progeny of) the limbal stem cells and the kinetics of the replacement of the donor corneal epithelium. The epithelial mass is constant under the normal circumstances and therefore the rate of cellular entry due to centripetal motion and mitosis into any epithelial volume must equal the cell loss from the same volume. The magnitude of the centripetal velocity and the rate of replacement of the donor tissue following keratoplasty are shown to depend only on the following directly quantifiable factors--the difference in the mitotic rates of the corneal and limbal epithelia and the radii of these two epithelia. The a priori model predictions are found to be in very good agreement with the observed centripetal velocities and the rate of corneal graft replacement. The model provides an independent support for the hypothesis that the stem cells for the corneal epithelium are located in the limbus and are responsible for a slow replenishment of the corneal epithelial cell. The model suggests some factors that diminish the centripetal supply of cells and thus provides insights into the pathogenesis of persistent corneal defects and delayed reepithelialization of defects and grafts. The model is suitable for interpreting and quantitatively correlating the influence of some epithelial alterations and drugs on the centripetal supply of epithelial cells.
我们使用群体平衡模型来研究角膜上皮细胞向心迁移的机制和速率、角膜缘干细胞衍生的细胞对角膜上皮群体的更新以及供体角膜上皮替代的动力学。在正常情况下，上皮细胞总量是恒定的，因此由于向心运动和有丝分裂进入任何上皮体积的细胞进入速率必须等于同一体积中的细胞损失速率。结果表明，角膜移植术后向心速度的大小和供体组织的替代速率仅取决于以下可直接量化的因素——角膜上皮和角膜缘上皮有丝分裂速率的差异以及这两种上皮的半径。先验模型预测结果与观察到的向心速度和角膜移植替代速率非常吻合。该模型为角膜上皮干细胞位于角膜缘并负责缓慢补充角膜上皮细胞这一假说提供了独立支持。该模型揭示了一些减少细胞向心供应的因素，从而为持续性角膜缺损以及缺损和移植物延迟再上皮化的发病机制提供了见解。该模型适用于解释和定量关联某些上皮改变和药物对上皮细胞向心供应的影响。
