Abstract
Purpose: :
To perform an immunohistochemical evaluation of corneas with INTACS for post LASIK keratectasia and keratoconus, obtained following corneal transplantation.
Methods: :
Corneas from one patient with INTACS for post LASIK keratectasia and one patient with INTACS for keratoconus were obtained within 3 hours after penetrating keratoplasty and cryostat sections were analyzed by immunofluorescence with antibodies to 27 extracellular matrix (ECM) components and proteinases.
Results: :
In the stroma of both corneas next to an INTACS implant, ECM components associated with fibrosis were observed. These included tenascin–c, fibrillin–1, type IV collagen α1/α2 chains, and type XIV collagen. Additionally, deposition of laminin–8, perlecan, and fibronectin was revealed in the same locations. In both cases, keratocytes around INTACS were positive for specific proteinases associated with stromal remodeling including cathepsin F, MMP–1, and MMP–7. The case with keratoconus displayed typical Bowman’s layer breaks with deposition of various ECM components; some keratocytes close to INTACS were positive for MMP–2 and MMP–9. In the case with keratectasia, keratocytes close to INTACS stained positive for stromelysins (MMP–3 and MMP–10). Patterns of urokinase, type IV collagen α3, α4, α6 chains, type VI collagen, laminin–5, and laminin–10 were similar to normal in both cases.
Conclusions: :
Abnormal accumulation of fibrotic ECM components and proteinases in close proximity of INTACS suggests ongoing lysis and remodeling of corneal stroma. Specific changes observed in each case may be related to underlying pathology
Keywords: laser • keratoconus • extracellular matrix