Abstract
Purpose: :
To test the hypothesis that myofibroblast differentiation at the graft/host interface is responsible for interface haze in a cat model of DSAEK.
Methods: :
DSAEK was performed on 10 eyes of 6 adult domestic short-hair cats. Corneal Ocular Coherence Tomography (OCT) was performed 2 times per week. Cats were sacrificed 11 to 27 days post-DSAEK, and their eyes were harvested for histology. H & E staining and immunohistochemistry for α-SMA, Thy-1, and Fibronectin were performed with DAPI as a counterstain.
Results: :
OCT showed an increase in reflectivity at the host/graft interface in all eyes at all time-points. A wound healing response characterized by increased cellularity and positive cell staining for α-SMA, Fibronectin and Thy-1 was observed in the interface of 5/10 eyes. This response spanned almost the whole interface in 1/5 eyes, about half the interface in 2/5 and only rare patches of the interface in the other 2/5. In general, most eyes exhibited decreased cellularity or a completely acellular zone at the host/graft interface; however, areas with α-SMA positive staining also exhibited increased cellularity. The wound healing response at the interface was consistently more vigorous towards the periphery of the graft and was often contiguous with a fibrous cap that covered the lateral edges of the graft. These fibrous caps were also present in eyes without an interface wound healing reaction. There was no correlation between time post-DSAEK and the presence or intensity of the wound healing response at the interface.
Conclusions: :
While OCT imaging showed increased interface reflectivity in all cat eyes after DSAEK, this was not consistently associated with myofibroblast differentiation at the graft/host interface. This suggests that characteristics of the interface other than myofibroblast differentiation, such as extracellular matrix composition and reorganization or collagen fiber diameter, spacing and orientation may be more important substrates of interface haze.
Keywords: transplantation • cornea: stroma and keratocytes • wound healing