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The ability of animal salivary glands to recover from an experimentally-induced atrophic state offers hope that human salivary glands may be regenerated following injury. Examination of the mechanisms of regeneration in animal models has revealed processes which resemble the embryonic formation of salivary glands. Secretory proteins present in regenerated acinar and ductal cells are the same as found in the perinatal salivary glands. The use of microarrays to reveal global gene changes has, in combination with bioinformatic techniques, identified some of the important signalling cascades operating in the early stages of glandular regeneration. The role of stem cells is also considered and would fit in with current ideas of glandular regeneration, however the isolation and subsequent differentiation of stem cells into a normal reflexly secreting gland still requires considerable research., (Copyright 2010 S. Karger AG, Basel.)

During salivary gland morphogenesis, the developing ducts and acini must hollow out to form lumina which will eventually allow the free passage and modification of saliva on its journey from acini to oral cavity. The molecular mechanisms that participate in the creation of this tubular structure are of great research interest. Histological studies show that lumen formation begins during the mid stages of branching morphogenesis. At this stage, apoptotic cells are detectable in the developing salivary ducts at sites where lumina are forming, suggesting that programmed cell death is instrumental in clearing the luminal space. The formation of cell-cell junctions between the epithelial cells lining the space is also an integral part of lumen formation, since these junctions form a barrier around the lumen and allow the surfaces of the lumen-lining cells to become specialized. This chapter will discuss the mechanisms involved in salivary gland lumen formation during development, and draw on the most recent research in this interesting field., (Copyright 2010 S. Karger AG, Basel.)

Human saliva chromogranin A (CgA) is clinically promising as a psychological stress marker. However, expression of CgA is poorly understood in humans, although salivary gland localization of CgA in other mammals, such as rodents and horses, has been demonstrated. In the present study, we investigated the expression and localization of CgA in the human submandibular gland (HSG) using various methods. CgA was consistently localized in serous and ductal cells in HSG, as detected by immunohistochemistry and in situhybridization. Reactivity was stronger in serous cells than in ductal cells. In addition, strong immunoreactivity for CgA was observed in the saliva matrix of ductal cavities. Western blotting gave one significant immunoreactive band of 68 kDa in the adrenal gland, HSG and saliva. Finally, CgA was detected in secretory granules of serous and ductal cells by immunoelectron microscopy. In conclusion, CgA in humans is produced by HSG and secreted into saliva.