The XXXX response to epithelial- @entity130 .

@entity82 @entity267 @entity231 @entity18737 @entity2318 @entity95 @entity72861 @entity130
UNASSIGNED: The corneal wound healing response, including the development of @entity231 in some eyes, is a process that often leads to @entity2318 that occurs after @entity130 to the @entity267 . Immediately after epithelial and @entity130 , a complex sequence of processes contributes to wound repair and regeneration of normal corneal structure and function. In some corneas, however, often depending on the type and extent of injury, the response may also lead to the development of mature vimentin+  a-smooth muscle actin+  @entity18737 +  myofibroblasts. Myofibroblasts are specialized fibroblastic cells generated in the @entity267 from keratocyte-derived or bone marrow-derived precursor cells. The disorganized extracellular matrix components secreted by myofibroblasts, in addition to decreased expression of corneal crystallins in these cells, are central biological processes that result in corneal stromal @entity82 associated with @entity231 or "haze". Several factors are associated with myofibroblast generation and haze development after PRK surgery in @entity95 , a reproducible model of @entity2318 , including the amount of tissue ablated, which may relate to the extent of keratocyte apoptosis in the early response to injury, irregularity of stromal surface after surgery, and changes in corneal stromal proteoglycans, but normal regeneration of the epithelial basement membrane (EBM) appears to be a critical factor determining whether a @entity267 heals with relative transparency or vision-limiting @entity231 . Structural and functional abnormalities of the regenerated EBM facilitate prolonged entry of epithelium-derived growth factors such as transforming growth factor b (TGF-b) and platelet-derived growth factor (PDGF) into the stroma that both drive development of mature myofibroblasts from precursor cells and lead to persistence of the cells in the anterior stroma. A major discovery that has contributed to our understanding of haze development is that keratocytes and corneal fibroblasts produce critical EBM components, such as @entity72861 , nidogen-2 and perlecan, that are essential for complete regeneration of a normal EBM once laminin secreted by epithelial cells self-polymerizes into a nascent EBM. Mature myofibroblasts that become established in the anterior stroma are a barrier to keratocyte/corneal fibroblast contributions to the nascent EBM. These myofibroblasts, and the @entity231 they produce, often persist for months or years after the injury. Transparency is subsequently restored when the EBM is completely regenerated, myofibroblasts are deprived of TGFb and undergo apoptosis, and the keratocytes re-occupy the anterior stroma and reabsorb disordered extracellular matrix. The aim of this review is to highlight factors involved in the generation of stromal haze and its subsequent removal.
