Three-dimensional aspects of matrix assembly by cells in the developing cornea

Area of Science:

• Ophthalmology
• Developmental Biology
• Biomaterials Science

Background:

• Corneal stroma formation relies on aligned collagen fibrils for transparency and biomechanical stability.
• Previous studies were limited by 2D imaging techniques, restricting understanding of 3D corneal microanatomy.

Purpose of the Study:

• To investigate the three-dimensional microanatomy of the developing cornea.
• To elucidate the role of corneal keratocytes and their structures in collagen fibril alignment.

Main Methods:

• Volume scanning electron microscopy utilizing focused ion beam ablation or serial block face microtomy.
• Three-dimensional reconstruction and Fourier analysis of corneal tissue microanatomy.

Main Results:

• Corneal keratocytes occupy a larger tissue volume than previously estimated.
• A distinct orthogonality in cell and matrix organization was identified.
• Extended, actin-associated cell protrusions (over 30 µm) were observed, mirroring collagen bundle alignment.

Conclusions:

• Corneal keratocyte cell protrusions are proposed to dictate collagen orientation during corneal development.
• This finding offers new insights into the mechanisms underlying corneal stromal development and organization.