An immunohistochemical study of the vasculature and stem cells and carbonic anhydrase IV in the ducts of irradiated and normal human submandibular salivary glands.

Therapeutic irradiation for cancers of the head and neck causes serious and irreversible damage to the salivary glands; the resulting adverse effects on salivary quality and quantity produce detrimental effects on teeth and oral mucosa. The salivary effects have been related mostly to loss of serous acini; damage to the ducts is relatively minor. Other radiation effects include fibrosis, adiposis and vascular damage. Stem cells in the salivary gland ducts have the potential to generate acinar cells in vitro and in vivo. I investigated the ducts and vasculature in irradiated and normal human submandibular glands using immunohistochemical localization of biomarkers of stem cells, duct function and blood vessels. Stem cell markers CK5 and Sca-1 labeled the cytoplasm of the basal and intercalated duct cells and all duct cells, respectively, in both normal and irradiated glands. CA IV, which participates in regulating salivary electrolytes and acid-base balance, labeled the cytoplasm of all ducts. CD34 labeling demonstrated more extensive vasculature in the irradiated glands than in the normal glands. My findings suggest that duct stem cells and at least one duct function persisted, and the vasculature was greater, despite moderate fibrosis, in the irradiated gland.