Abstract
Purpose: :
The integrity of the cornea is critical for vision. Partial or complete blindness may be the result of a corneal injury or surgery, with treatment options generally limited to corneal transplantation. With the decrease in donor tissue, scientists have turned to adult stem cells and their ability to regenerate tissue to help resolve this dilemma. Recently, human umbilical cord mesenchymal stem cells (UCB-MSCs) have been investigated for tissue engineering and therapy. Their availability and their differentiation potential make them highly attractive for use in artificial, in vitro applications. We used UCB-MSCs in our in vitro 3-dimensional (3D) stromal-like model to observe their ability to stratify and lay down an organized extracellular matrix (ECM).
Methods: :
Cells were stimulated by a stable Vitamin C (VitC) derivative and were grown under these conditions for 4 weeks before being processed for analysis by indirect-immunofluorescence microscopy (IF) and transmission electron microscopy (TEM). Human corneal fibroblasts (HCFs) were used as control.
Results: :
After 4 weeks in culture, UCB-MSCs stimulated with VitC stratified to a mean thickness of approximately 30µm, similar to HCF, and showed 50% less cells per unit area when compared to HCF, indicating higher amounts of matrix. Collagen III at high levels was found mainly in the middle of the UCB-MSC constructs, smooth muscle-actin (SMA) expression was seen throughout both types of constructs, and the cell-ECMinteraction appeared to have aligned collagen with long fibrils in both HCF and UCB-MSC constructs.
Conclusions: :
Overall, the data suggests that UCB-MSCs can stimulate matrix deposition in this 3D model and may be considered as an alternative to HCFs. Our results showed expression of specific markers that may be present in cornea following wound or injury, such as collagen III and SMA; however, further development of this model is currently ongoing.
Keywords: cornea: stroma and keratocytes • extracellular matrix