Collagen cross-linking impact on keratoconus extracellular matrix

Area of Science:

• Ophthalmology
• Biomaterials Science
• Cell Biology

Background:

• Keratoconus (KC) is a common, multifactorial corneal disease affecting vision, often appearing in adolescence.
• Current treatments for advanced KC include collagen cross-linking (CXL) and corneal transplants.
• CXL shows promise in arresting KC progression, but its availability is limited.

Purpose of the Study:

• To investigate the effects of CXL on the corneal microenvironment.
• To elucidate the molecular mechanisms underlying CXL's therapeutic action.
• To inform the development of more patient-specific CXL treatments.

Main Methods:

• Utilized a 3D in vitro model with primary human corneal fibroblasts from healthy and KC donors.
• Stimulated cells with vitamin C, followed by riboflavin and UVA irradiation to mimic CXL.
• Assessed extracellular matrix (ECM) and cellular changes using Transmission Electron Microscopy (TEM) and western blots.

Main Results:

• CXL significantly improved lamellar organization and collagen fibril structure.
• Proteoglycans (lumican, mimecan, decorin) were upregulated post-CXL.
• Expression of matrix metalloproteinases (MMPs -1, -3, -9) was downregulated, indicating reduced ECM degradation.

Conclusions:

• CXL positively modulates the corneal microenvironment by enhancing ECM structure and reducing degradation.
• This study provides critical insights into CXL's mechanism of action in a 3D model.
• Understanding these effects could expand CXL eligibility for keratoconus patients.