Primary culture of polarized human salivary epithelial cells for use in developing an artificial salivary gland

Abstract

Therapeutic irradiation for head and neck cancer, and the autoimmune disease Sjogren's syndrome, lead to loss of salivary parenchyma. They are the two main causes of irreversible salivary gland hypofunction. Such patients cannot produce adequate levels of saliva, leading to considerable morbidity. We are working to develop an artificial salivary gland for such patients. A major problem in this endeavor has been the difficulty in obtaining a suitable autologous cellular component. This article describes a method of culturing and expanding primary salivary cells obtained from human submandibular glands (huSMGs) that is serum free and yields cells that are epithelial in nature. These include morphological (light and transmission electron microscopy [TEM]), protein expression (immunologically positive for ZO-1, claudin-1, and E-cadherin), and functional evidence. Under confocal microscopy, huSMG cells show polarization and appropriately localize tight junction proteins. TEM micrographs show an absence of dense core granules, but confirm the presence of tight and intermediate junctions and desmosomes between the cells. Functional assays showed that huSMG cells have high transepithelial electrical resistance and low rates of paracellular fluid movement. Additionally, huSMG cells show a normal karyotype without any morphological or numerical abnormalities, and most closely resemble striated and excretory duct cells in appearance. We conclude that this culture method for obtaining autologous human salivary cells should be useful in developing an artificial salivary gland.