SUBSTRATE MODULATION OF MORPHOLOGY, GROWTH, AND TEAR PROTEIN-PRODUCTION BY CULTURED HUMAN LACRIMAL GLAND EPITHELIAL-CELLS

Human lacrimal gland biopsies were serially incubated in chelating and enzymatic solutions. Viable single cells were evaluated for outgrowth in growth factor enriched medium using the following culture substrat es: Matrigel, Type I collagen gel with or without fibroblasts, and pla stic. Each epithelial outgrowth was characterized morphologically and immunohistochemically, and their growth and viability were examined by BrdU labeling and a quantitative cell viability assay. Synthesized pr oteins were evaluated by ELISA, SDS-PAGE, and C-14-labeled amino acid incorporation. Lacrimal gland epithelial cells plated on Matrigel form ed clusters with central cavities that contained lactoferrin, mimickin g acinar complexes in vivo. Cells plated on collagen gel or collagen g el containing fibroblasts formed islands or a monolayer, and lactoferr in was detected in incomplete cavities of epithelia on the latter subs trate. Epithelial cells plated on plastic formed a monolayer and cellu lar expression of lactoferrin was weak and sporadic. Cellular release of lactoferrin measured by ELISA supported the results of immunohistoc hemistry. Cells grown on plastic had the highest proliferative rate, w hereas those grown on Matrigel showed the lowest proliferative rate. T hese results indicate that different substrates modulate lacrimal glan d epithelial cell morphology, proliferative rate, and production of th e tear protein lactoferrin. Matrigel promotes acinar differentiation t o a greater extent than collagen gel and plastic. Incorporation of fib roblasts in collagen gel substrate promotes significant effects on gro wth and differentiation. (C) 1995 Academic Press, Inc.