Table 1.
Molecules involved in corneal transparency and avascularity.
| Corneal crystallins |
| -aldehyde dehydrogenase (ALDH) |
| -transketolase (TKT) |
| Promotor of transformation of keratocyte to corneal myofibroblast |
| -extracellular matrix metalloproteinase inducer (EMMPRIN)/CD147 |
| Matrix metalloproteinases (MMPs) involved in corneal healing |
| -Specific expression by corneal fibroblasts; sustained expression |
| -MMP-1/fibroblast collagenase |
| -MMP-2/gelatinase A |
| -MMP-3/stromelysin |
| -Short-term expression |
| -MMP-8/neutrophil collagenase |
| -MMP-9/gelatinase B |
| Signal proteins modulating keratocyte action |
| -Transforming growth factor beta-1 (TGF-β1)—appears to promote healing/scar formation |
| -Transforming growth factor beta-3 (TGF- β3)—appears to inhibit healing/scar formation |
| -Interleukin-10 (IL-10)—appears to inhibit healing/scar formation |
| -Fibroblast growth factor-2 (FGF-2)—inhibits TGF-β1 expression |
| -Connective tissue growth factor (CTGF)—synergizes with TGF-β1 |
| -Epidermal growth factor (EGF)—synergizes with TGF-β1 |
| Molecules involved in penetrating keratoplasty graft rejection |
| -Pro-hemangiogenic/lymphangiogenic |
| -Vascular endothelial growth factor (VEGF) isoforms and its associated receptors |
| -Vascular endothelial growth factor-A (VEGF-A)—specifically also promotes lymphangiogenesis |
| -Vascular endothelial growth factor-C (VEGF-C)—specifically also promotes lymphangiogenesis |
| -Vascular endothelial growth factor receptor-3 (VEGF-R3)—specifically also promotes |
| lymphangiogenesis |
| -Cell surface integrin α1β1—presumably involved in endothelial migration |
| -Anti-angiogenic |
| -Fas ligand (FasL)—two forms, mFasL (membrane-bound) and sFasL (soluble); unclear roles of each |
| - Thrombospondin 1 (TSP-1) |
| - Pigment Epithelial Derived Factor (PEDF) |
| - Interferon gamma |
| -Soluble VEGF receptors |
| -sVEGFR-1 (sFlt-1) |
| -sVEGFR-2 (sFlk-1) |
| -Other signal molecules that promote rejection |
| -Tumor necrosis factor alpha (TNF-α) |
| -Tumor necrosis factor beta (TNF-β) |
| -Interleukin-1 (IL-1) |
| -Other signal molecules that inhibit rejection |
| -Transforming growth factor beta-2 (TGF- β2) |