Tuesday, March 15, 2011

Corneal Keratocyte (Fibroblasts)

Corneal keratocytes, also known as corneal fibroblasts, are specialized cells which reside in the stroma of the eye cornea. The function of keratocytes is to keep the stroma transparent, healing its wounds, and synthesizing its components. Another important function of the keratocytes is to produce the lamellae, which are plates of collagen fibrils that make up the corneal stroma. Some keratocytes underlying the site of injury, even a light one, undergo apoptosis (programmed cell death) immediately after the injury. Excessive keratocyte apoptosis may be a part of the pathological process in the degenerative corneal disorders such as keratoconus, and these considerations prompt the ongoing research into the function of these cells.

Keratocytes secrete a unique population of proteoglycan molecules considered essential for corneal transparency. Keratocytes have been implicated as the source of fibrotic tissue in nontransparent corneal scars. Their secretion pattern changes during corneal wound healing, when the cells assume the phenotypes of myofibroblasts in response to TGF-beta (Funderburgh et al, 1998). A detailed study of keratocyte expression profiles in response to TGF-beta-1 and before and after the activation of quiescent corneal stromal keratocytes to contractile myofibroblasts has been reported by Harvey ety al (2010).