Gland and epithelium formation in vitro from epithelial cells of the human endometrium.

As is often the case with cell culture, normal human endometrial epithelial cells show a low, squamous shape with flattened nuclei and lack three-dimensional morphology in in-vitro culture systems. Here we report the first well-differentiated epithelial culture system using basement membrane extracts (BME) from an Engelbreth-Holm-Swarm tumour (EHS tumour). In this model, BME regulated the reconstruction of glandular formation and subsequent reformation of the epithelium by epithelial cells. An electron microscopic study clearly indicated that there were two distinct types of cells grown on the substrate. The first, having a high columnar shape, formed the glandular epithelium, and the second, having a cuboidal shape, covered the surface of the BME. Study of epithelial reformation indicated that the regeneration of superficial epithelium could occur, following the development of the glandular formation, in a helix-like pattern. Total protein secretion was greater when the cells were grown on the BME than on plastic. Thus, normal human endometrial epithelial cells cultured on the BME assumed a phenotype and morphology characteristic of those in vivo.