Over-expression of human cystatin C in pterygium versus healthy conjunctiva

A prospective, non-randomised, transversal and comparative study, carried out in INOVA Vision Institute and Autonomous University of Aguascalientes. Pterygium is an important illness that affects 22% people from tropic and equatorial zones. Is an inflammatory process caused by UV rays, and it has a behavior similar to a neoplasm. For this study was taken into consideration 191 samples from the INOVA Vision Institute, Aguascalientes, Mexico. Include 73 pterygia samples, which were obtained during resection under sterile conditions. 44 normal conjunctiva samples were obtained from the same patients when harvesting the conjunctival autograft, or from other patients undergoing extracapsular cataract extraction from the superior bulbar region. Tears from patients with pterygium (n = 50) and normal volunteers (n = 24) were obtained using a calibrated glass micro capillary tube. The surgical conjunctiva and pterygia samples were subjected to reverse-transcription polymerase chain reaction (RT-PCR), western blot, and immunohistochemistry. Tears were analyzed by enzyme-linked immunosorbent assays.

This was a prospective, non-randomised study involving 191 biological samples taken from patients with pterygium and normal volunteers, whom were operated under local anaesthesia by either complete resection of the lesion with primary closure, or resection with conjunctival autograft. Tissue samples were fixed in 10% formaldehyde. Sections were routinely stained with hematoxylin and eosin. HCC expression was evaluated by reverse-transcription polymerase chain reaction (RT-PCR), immunohistochemistry, and by western blotting. All tears samples were analyzed by enzyme-linked immunosorbent assays (ELISA).

Expression levels and distribution patterns of HCC in normal conjunctiva and pterygium. Higher levels of HCC mRNAs and proteins were detected in pterygium compared with a normal conjunctiva. Immunohistochemistry revealed that HCC was localized in the apical cells of the epithelium in the normal conjunctiva. In contrast, HCC was detected in all extension of epithelial tissue, from apical to basal cells in pterygia. The concentration of HCC protein in tears was higher in patients with pterygium versus controls.

HCC may play an important role in protecting normal conjunctiva, and regulating inflammatory conditions of the anterior ocular surface.