[Characterization of epithelial primary culture from human conjunctiva]

The conjunctival extracellular matrix, related disorders and development of substrates for conjunctival restoration

The conjunctiva can be damaged by numerous diseases with scarring, loss of tissue and dysfunction. Depending on extent of damage, restoration of function may require a conjunctival graft. A wide variety of biological and synthetic substrates have been tested in the search for optimal conditions for ex vivo culture of conjunctival epithelial cells as a route toward tissue grafts. Each substrate has specific advantages but also disadvantages related to their unique physical and biological characteristics, and identification and development of an improved substrate remains a priority. To achieve the goal of mimicking and restoring a biological material, requires information from the material. Specifically, extracellular matrix (ECM) derived from conjunctival tissue. Knowledge of the composition and structure of native ECM and identifying contributions of individual components to its function would enable using or mimicking those components to develop improved biological substrates. ECM is comprised of two components: basement membrane secreted predominantly by epithelial cells containing laminins and type IV collagens, which directly support epithelial and goblet cell adhesion differentiation and growth and, interstitial matrix secreted by fibroblasts in lamina propria, which provides mechanical and structural support. This review presents current knowledge on anatomy, composition of conjunctival ECM and related conjunctival disorders. Requirements of potential substrates for conjunctival tissue engineering and transplantation are discussed. Biological and synthetic substrates and their components are described in an accompanying review.

Characterization of doxycycline-dependent inducible Simian Virus 40 large T antigen immortalized human conjunctival epithelial cell line

PURPOSE

To present the properties of a newly developed immortalized human conjunctival epithelial cell (iHCjEC) line.

METHODS

iHCjECs were developed to induce Simian Virus 40 large T-antigen (SV40LT) by incorporating lentivirus in a tetracycline (Tet)-regulated gene-expression system into primary cultures of human conjunctival epithelial cells. The population doubling time and morphology of the iHCjECs were analyzed. The expressions of CK13, CK19, CK12, and MUC1, MUC4, MUC16, and MUC5AC were determined by real time PCR and immunohistochemically under different culture conditions. The organotypic culture model in which iHCjECs were cultured on rabbit conjunctival fibroblast-embedded collagen gel was used to characterize the iHCjECs.

RESULTS

The iHCjECs cultured with doxycycline (Dox) continued to proliferate for at least 20 passages and had a cobblestone-like appearance. The expressions of CK13 and CK19 but not CK12 were detected in the iHCjECs, and the expression of CK13 increased in culture media lacking Dox (Dox-). The expressions of MUC1, MUC4, MUC16, and MUC5AC were detected in iHCjECs, and a relatively strong immunostaining of MUC5AC was detected with Dox(-) added 5% FBS. Stratified iHCjECs were observed in organotypic culture at 5 days.

CONCLUSION

The iHCjECs had high proliferation rates and abilities to control the differentiation potency to control the expression of SV40 LT-antigen with Tet-regulated gene-expression system. They are able to express the mucin gene repertoire of their native epithelia. The iHCjECs can be a useful experimental cell line to study conjunctival epithelial cell characteristics and for pathophysiological and toxicological studies.