Fibroblastic and bone marrow-derived cellularity in the corneal stroma

Area of Science:

• Ophthalmology
• Cell Biology
• Tissue Repair

Background:

• The normal corneal stroma contains quiescent keratocytes, nerves, and immune cells.
• Recent research indicates heterogeneity within keratocyte populations and the presence of stromal stem cells.
• Corneal wounding induces significant alterations in stromal cellular composition.

Purpose of the Study:

• To elucidate the cellular and molecular mechanisms underlying corneal stromal repair and fibrosis.
• To investigate the role of growth factors and basement membrane integrity in wound healing.
• To understand the transition of corneal cells and the infiltration of bone marrow-derived cells post-injury.

Main Methods:

• Analysis of cellular changes in the corneal stroma following injury.
• Investigation of growth factor signaling pathways (TGF-β1, TGF-β2, PDGF).
• Assessment of epithelial barrier function (EBF), epithelial basement membrane (EBM), and Descemet's basement membrane (DBM) integrity.

Main Results:

• Corneal injuries induce keratocyte apoptosis and transformation into fibroblasts.
• Bone marrow-derived cells (monocytes, fibrocytes) infiltrate the stroma.
• Sustained TGF-β signaling due to defective barrier function drives myofibroblast differentiation and extracellular matrix deposition, leading to fibrosis.
• Timely repair of EBF, EBM, and DBM promotes resolution of fibrosis through apoptosis or reversion of myofibroblasts.

Conclusions:

• Corneal fibrosis is a consequence of persistent myofibroblast activation driven by impaired barrier repair and sustained growth factor signaling.
• Keratocyte plasticity and the infiltration of extrinsic cells are key components of the wound healing response.
• Understanding these processes is crucial for developing strategies to prevent or treat corneal scarring.