Culture of human endometrial cells under polarizing conditions.

Glandular epithelial and stromal cells were isolated from human endometrial biopsies and cultured in a dual-chambered system (Millicell; Millipore, Bedford, Ma., USA) that provides access of the medium to both sides of a membrane coated with reconstituted basement membrane material (Matrigel; Collaborative Research Inc., Bedford, Ma., USA). Examination by electron microscopy revealed that the epithelial cells formed a polarized cuboidal-columnar monolayer on the Matrigel surface. The cells exhibited apical microvilli, basal nuclei, and numerous cytoplasmic structures consistent with a well-differentiated cytoplasm; they were joined basally by interdigitating processes and apically by tight junctions and desmosomes. In contrast, epithelial cells cultured in parallel on plastic dishes were flattened, had fewer microvilli and cytoplasmic structures, and no junctional complexes.