Building a 3D model of the human keratoconic cornea

Abstract

Keratoconus is a corneal disease characterized by the affected tissue adopting a conical shape, leading to loss of vision and compromised structural integrity. The disease is manageable in its early stage with lenses or glasses and can be treated in its later stages with surgery or crosslinking. The underlying cause of the disease is still poorly understood, a model would aid the exploration of this disease. In this study, primary stromal cells harvested from healthy and keratoconic corneas using a variety of extraction methods were cultured in compressed collagen gels and serum-free medium containing retinoic acid to simulate the cornea’s natural environment. The survival of stromal cells and their gene expression was assayed, paying special attention to genes related to differentiation and ECM maintenance. Among healthy cells, differences were identified between limbal and central population while central keratoconic cells more closely resembled healthy limbal cells. Use of retinoic acid as a medium supplement allowed for the culture of cells in serum-free conditions and caused gene expression that resembled in vivo behaviour. The final addition of ECM in the form of curved, compressed collagen gels to this culture system caused the stromal cells to radically change their behaviour and reaction to retinoic acid. Overall, this study identified a stromal tissue model as well as the multiple considerations in the construction of such a model. The use of this model in keratoconus research may lead to breakthroughs in attempts to better understand the disease.