Localization of lysozyme mRNA in the labial salivary glands by in situ hybridization in Sj?gren's syndrome

In this study, lysozyme mRNA in labial salivary glands has been localized with in situ hybridization technique using 35S-labeled hen lysozyme cDNA (cDNALZM) as a hybridization probe in normals and in patients with Sj?gren's syndrome, 35S-DNALZM:mRNA hybrids were detected only in acinar serous cells, although lysozyme was identified in ductal cells using immunohistochemical techniques. Our results suggest that the serous acinar cells are the only site of lysozyme synthesis in small salivary glands. The presence of lysozyme in ductal cells may be a result of reabsorption from the saliva or concentration from the blood or surrounding tissues.     

Expression of two drug-metabolizing cytochrome P450-enzymes in human salivary glands

Objective:  The oral cavity is constantly lubricated by saliva and even small amounts of xenobiotics and / or their metabolites in the saliva may affect the oral mucosa. Our aim was therefore to clarify if xenobiotic metabolizing enzymes CYP1A2 and CYP3A4 are expressed in salivary glands.
Methods:  Formalin-fixed paraffin-embedded specimens from parotid (10), submandibular (7) and labial (10) salivary glands were examined immunohistochemically and by in situ hybridization for expression of CYP1A2 and CYP3A4 protein and mRNA.
Results:  CYP1A2 and CYP3A4 protein and mRNA were detected in ductal and seromucous / serous acinar cells in all gland types although to a varying degree and intensity. Mucous acinar cells were positive to a lesser extent.
Conclusion:  The results indicate a xenobiotic metabolizing capability of salivary glands. This may have implications for development of oral mucosal disease as a result of mucosal exposure to metabolites originating from internal sources (blood) as well as from saliva.     

Immunohistochemical observations on carbonic anhydrase I and II in human salivary glands and submandibular obstructive adenitis

Abstract Immunohistochemical identification of carbonic anhydrase I and II (CA-I, CA-II) was made in human major salivary glands and obstructive adenitis in submandibular glands. Normal salivary glands stained the strongest for CA-II in serous acinar cells and were negative in mucous cells. Moderate to strong staining for CA-I and CA-II was found in ductal segments. Submandibular glands with obstructive adenitis exhibited reduced CA-1 activity in atrophic acinar cells, but not in ductal elements in the early and intermediate stages of the disorder. In the late stage of the obstructive lesion, CA staining in duct-like structures was moderate; however, almost degenerate ductal cells were negative for CA. During the progression of the degeneration in the obstructive lesion, the CA staining decreased dependent on acinar atrophy. Even after longstanding obstruction of the salivary gland, altered ductal epithelia may retain some of their functions.     

Immunohistochemical localization of lectins in normal salivary glands and mucoepidermoid carcinoma

5 kinds of Lectins (ConA, PNA, RCA, SBA and WGA) were used to observe the immunochemical localization of lectins in the cells of normal salivary glands and mucoepidermoid carcinoma. The result shows that in normal salivary glands ConA staining was found only in duct cells and serous acinar cells. Intercalated duct cells and striated duct cells of parotid and submandibular gland displayed RCA and WGA staining. The duct cells of sublingual gland and palatine gland did not react with lectin RCA. The ductal and acinar cells of normal salivary gland were not stained by PNA. Serous acinar cells of sublingual gland could be stained by SBA but mucous cells were negative. In tumor cells, ConA, RCA, WGA showed extensive staining which suggests the tumor cells contain similar glycoproteins as the normal duct cells. PNA was found in squamous epithelial cells but not in glandular epithelium. Its presence in tumor cells may indicate the degree of differentiation of these cells. Epidermoid and mucous cells of the tumor were also stained by 54 Kd antikeratin antibody. The results suggest this tumor may originate from the ductal cells of salivary gland.     

Nucleolar organizer regions (NORs) evaluation of lingual salivary glands of chronic alcoholics

BACKGROUND: Chronic alcoholism has been associated with structural and physiological changes in salivary glands. Studies on a variety of pathologies have suggested that variation in number of nucleolar organizer regions (NORs) reveals conditions of cellular activity. The aim of this work was to examine, through the AgNOR technique, changes in number and size of NORs in lingual salivary glands of chronic alcoholics. METHODS: Samples of mucous and serous lingual salivary glands were obtained from tongues from autopsies of individuals whose cause of death was hepatic alcoholic cirrhosis. Lingual organs from individuals whose cause of death was accidental were used as controls. Number and size of the AgNORs and nuclear area, in ductal and acinar cells, were evaluated through a digital image analyzer. RESULTS: Statistical analysis revealed differences (P < or = 0.05) in number of AgNORs in mucous acini and ductal cells. Also, we observed changes in the area of the NORs. CONCLUSION: These results suggest that in alcoholics the activity of glandular cells, mainly in ductal epithelium, could be affected, modifying synthesis, transport and salivary secretions.     

P-glycoprotein expression in human major and minor salivary glands

Sodium pump and carbonic anhydrase activity have been described in the salivary glands. However, it remains to be elucidated whether these energy sources are used for secretion, excretion or both. In addition, the differences in the function of excretion and the role of the excretory duct cells are currently unknown in salivary glands. Expression of P-glycoprotein (P-gp), which is an ATPase-binding efflux pump, was tested in normal major and minor salivary glands from humans. P-gp was distributed on the basolateral membrane of serous acinar cells in the major salivary glands and the minor salivary glands. In particular, it was found to be present on the basolateral membrane and cytoplasm of acinar demilunar cells in the anterior lingual gland. Intense expression was identified in the basolateral membrane of the striated duct cells of the major salivary glands. P-gp was distinctly positive in the basolateral and/or luminal membranes of the initial part and in the luminal membrane of the terminal part of the excretory duct cells of the major salivary glands, whereas it was positive in the luminal membranes of both the initial part and the terminal part of the excretory duct cells of the minor salivary glands. These disparate distributions between the major and the minor salivary glands suggest different physiological excretions in the striated duct. P-gp may be physiologically involved in an important part of the transporter system, not only in the acinar serous cells and the striated duct cells, but also in the excretory duct cells in the salivary glands.     

Cell surface markers CD44 and CD166 localized specific populations of salivary acinar cells

Oral Diseases (2012) 18 , 162–168 Objective: Experimental approaches tested to date for functional restoration of salivary glands (SGs) are tissue engineering, gene transfer, and cell therapy. To further develop these therapies, identifying specific cell surface markers for the isolation of salivary acinar cells is needed. To test a panel of cell surface markers [used in the isolation of mesenchymal stem cells, (MSCs)] for the localization of salivary acinar cells. Materials: Human submandibular and parotid glands were immunostained with a panel of MSC markers and co‐localized with salivary acinar cell differentiation markers [α‐amylase, Na‐K‐2Cl cotransporter‐1, aquaporin‐5 (AQP5)]. Additional cell markers were also used, such as α‐smooth muscle actin (to identify myoepithelial cells), cytokeratin‐5 (basal ductal cells), and c‐Kit (progenitor cells). Results: CD44 identified serous acini, while CD166 identified mucous acini. Cytokeratin‐5 identified basal duct cells and 50% of myoepithelial cells. None of the remaining cell surface markers (Stro‐1, CD90, CD106, CD105, CD146, CD19, CD45, and c‐Kit) were expressed in any human salivary cell. Conclusions: CD44 and CD166 localized human salivary serous and mucous acinar cells, respectively. These two cell surface markers will be useful in the isolation of specific populations of salivary acinar cells.     

Histological study of parotid,submaxillary and von Ebner salivary glands in chronic alcoholics

Samples from parotid, submaxillary, and von Ebner salivary glands of six chronic alcoholic individuals who had died of alcoholic hepatic cirrhosis were analyzed by topographic and histochemical routine stains and marked for cytokeratins; two normal adult individuals were used as control. Modifications in the acinar cells were found, but the most evident changes were observed in the ductal system: enlargement of major ducts, heterogeneous expression of cytokeratins and athrophy in epithelial cells, desquamated cells and stasis of content, and ductal hyperplasia in von Ebner glands. The lymphoplasmocytic infiltration does not represent the typical lymphocytic focus on Sj?gren's syndrome or other connective tissue pathologies. Our findings indicate that functional and structural variations are produced both in serous acini and ducts parotid, submaxilar and von Ebner glands affected by alcoholic sialosis.     

Morphological features of the minor salivary glands

The minor salivary, glands are important components of the oral cavity, present in most parts of the mouth, and their secretions directly bathe the tissues. Individual glands are usually in the submucosa or between muscle fibres, and consist of groups of secretory endpieces made up of mucous acinar cells and serous or seromucous demilune cells. The ductal systems comprise intercalated ducts, intralobular ducts usually lacking basal striations, and excretory ducts opening directly through the mucosa. Minor glands secrete highly glycosylated mucins, containing blood group determinants, and probably active in tissue lubrication and bacterial aggregation. They also secrete several antimicrobial proteins and immunoglobulins, and the lingual serous (van Ebner's) glands secrete digestive enzymes and proteins with possible taste perception functions. Minor gland morphology and function can conveniently be studied in the rat. There are substantial differences between major and minor salivary glands, as well as among the minor glands, in the nature and composition of their mucous and serous secretory products. The role of minor salivary glands in the function and defence of the oral cavity may be better understood as a result of new physiological and molecular methods applicable to samples of limited size and availability.     

Immunohistochemical observations on carbonic anhydrase I and II in human salivary glands and submandibular obstructive adenitis

Immunohistochemical identification of carbonic anhydrase I and II (CA-I, CA-II) was made in human major salivary glands and obstructive adenitis in submandibular glands. Normal salivary glands stained the strongest for CA-II in serious acinar cells and were negative in mucous cells. Moderate to strong staining for CA-I and CA-II was found in ductal segments. Submandibular glands with obstructive adenitis exhibited reduced CA-I activity in atrophic acinar cells, but not in ductal elements in the early and intermediate stages of the disorder. In the late stage of the obstructive lesion, CA staining in duct-like structures was moderate; however, almost degenerate ductal cells were negative for CA. During the progression of the degeneration in the obstructive lesion, the CA staining decreased dependent on acinar atrophy. Even after longstanding obstruction of the salivary gland, altered ductal epithelia may retain some of their functions.     

Immunohistochemical localization of amylase in sialoadenitis and salivary gland tumors

Immunohistochemical demonstration of alpha-amylase has been made in sialoadenitis-involved tissue and salivary gland tumors, as well as in normal salivary glands. Immunoreactive alpha-amylase with trypsin pretreatment was confined to irregularly staining serous acinar cells in the parotid and submandibular glands, and to demilunes in sublingual glands. In obstructive adenitis, staining was irregular from high to negative in acini in early or intermediate stages. Dilated ductal segments contained cells positive for alpha-amylase in the early stage following obstruction. Pleomorphic adenomas were usually negative for alpha-amylase but in rare cases tumor epithelia stained variably positive; i.e., staining occurred throughout the cytoplasm or at the periphery or apical part of the tumor cells. Luminal cavities of tubular and duct-like structures contained alpha-amylase-positive material. Epithelia in Warthin's tumor were also negative in general; however, scattered single or grouped tumor cells containing alpha-amylase were found. Mucoepidermoid tumors were also negative, though slightly positive cells were found intermingled among the negative squamous and mucous tumor cells. Cystic lesions in mucoepidermoid tumor were sometimes positive in the wall cells together with material secreted into the lumen.     

Immunohistochemical localization of amylase in sialoadenitis and salivary gland tumors

Immunohistochemical demonstration of α-amylase has been made in sialoadenitis-involved tissue and salivary gland tumors, as well as in normal salivary glands. Immunoreactive α-amylase with trypsin pretreatment was confined to irregularly staining serous acinar cells in the parotid and submandibular glands, and to demilunes in subligual glands. In obstructivce adenitis, staining was irregular from high to negative in acini in early or intermediate stages. Dilated ductal segments contained cells positive for α-amylase in the early stage following obstruction. Pleomorphic adenomas were usually negative for α-amylase but in rare cases tumor epithelia stained variably positive; i.e., staining occurred throughout the cytoplasm or at the periphery or apical part of the tumor cells. Luminal cavities of tubular and duct-like structures contained α-amylase-positive material. Epithelia in Warthin's tumor were also negative in general; however, scattered single or grouped tumor cells containing α-amylase were found. Mucoepidermoid tumors were also negative, though slightly positive cells were found intermingled among the negative squamous and mucous tumor cells. Cystic lesions in mucoepidermoid tumor were sometimes positive in the wall cells together with material secreted into the lumen.     

A structural and immunocytochemical study of palatine and labial salivary glands from chronic alcoholics

In the present study we investigated tissue changes in palatine (PG) and labial (LG) minor salivary glands from individuals who had died of alcoholic hepatic cirrhosis, to characterize histopathological parameters of alcoholic sialosis, that may be used for differential diagnosis. Samples obtained from autopsies were processed using cytochemical techniques for mucosubstances and immunocytochemical labelling for cytokeratines, PS 100 and T-cells. Both PG and LG showed dilated excretory ducts with atrophic epithelium, which contained PAS+ metachromatic material and detached cells. Intra and interlobular ductal hyperplasia was present in some areas, mainly in PG. CK expression was heterogeneous in ductal cells, and negative in acinar cells. Most of the acinar cell nuclei were normal, but some of them were atypical in shape and distribution. Myoepithelial cells, serous demilunes and the basal region of the cells of the striated ducts expressed PS 100. In PG, 85% of the mononuclear infiltrates expressed T-cell markers, whereas in LG only 40% of these cells were T-cells. These findings, in addition to other histopathological parameters seen in previous studies, may be used as indicators for differential diagnosis with other gland pathologies.     

Immunohistochemical studies of organic anion transporters and urate transporter 1 expression in human salivary gland

Abstract

Background. Various substances including uric acid, organic acids and drugs are transported by organic anion transporters (OATs) in the kidney. In addition, a member of the OAT family, urate transporter 1 (URAT1), is involved in the reabsorption of uric acid from the renal tubule. Benzbromarone inhibits URAT1 to block uric acid reabsorption. Methods. Our group previously observed higher salivary uric acid levels than serum levels in patients taking benzbromarone, and reported the possible existence of URAT1-like uric acid excretion mechanism in the salivary gland. The purpose of this study was to elucidate the uric acid excretion mechanism in salivary gland tissues using rabbit anti-human OAT1-4 and URAT1 polyclonal antibodies with EnVision^? system. Results. In the salivary gland, OAT1 was expressed in ductal cells. OAT2 was found in both ductal cells and serous acinar cells and weak expression was also observed in several nuclei. OAT3 expression was observed in serous acinar cells and nuclei and OAT4 was expressed only in ductal cells. URAT1 expression was observed in the cytoplasm of ductal cells and strong punctuate staining was seen in part of the supra-nuclear cytoplasm. The number of cells expressing URAT1 was smaller compared with OATs. In the kidney, however, OAT1-4 and URAT1 were strongly expressed on proximal renal tubules. Conclusions. The present study confirmed the existence of OAT1-4 and URAT1 in the salivary gland. These results may support the previous speculation that benzbromarone inhibits URAT1 to block uric acid reabsorption in the salivary gland, resulting in higher salivary uric acid levels than serum levels.     

Immunohistochemical distribution of immunoglobulins, lactoferrin, and lysozyme in human minor salivary glands

The immunoflorescence technique was used to examine the distribution of immunoglobulin A and its subclasses, secretory component (SC), J chain, lactoferrin and lysozyme in labial and lingual (von Ebner's) glands. IgA-containing plasma cells were found in the connective tissue around intercalated or intralobular duels and a few were noted around acini of both glands. IgA was detected in the apical cytoplasm of intercalated and intralobular duct cells and in acini of von Ebner's glands and in demilunes of labial glands. Most IgA-containing cells also stained for J chain. The ratio of IgA1:IgA2-containing cells was approximately equal in von Ebner's and labial glands. Cytoplasmic and surface membrane-related staining for SC was detected in epithelial cells of the intercalated and intralobular ducts in both glands, in the serous acini of von Ebner's gland, and in the demilunes of labial glands. Lactoferrin was found in serous acini, demilunes, intercalated and intralobular ducts. Lysozyme was found in acinar and intercalated duels, but was rarely seen in intralobular ducts. These results disclose the presence of cells (plasma cells and epithelial cells) and their products (IgA and secretory component) that indicate the local production of secretory IgA in minor salivary glands.     

Salivary gland disorders: A comprehensive review

Salivary glands are complex in nature. They could be either tubulo acinar, merocrine or exocrine glands secreting mainly saliva. Salivary gland is one of the main soft tissue structures in the maxillofacial area. Saliva is a clear, slightly acidic muco serous fluid that coats the teeth, mucosa and thereby helps to create and maintain a healthy environment in the oral cavity. Salivary glands may be affected by a number of diseases: local and systemic and the prevalence of salivary gland diseases depend on various etiological factors. The glands may be infected by viral, bacterial, rarely fungal or its ductal obstruction which may cause painful swelling or obstruction, affecting their functions. The salivary gland may also be affected by a various benign and malignant tumours. This review article briefly describes about the various salivary gland disorders, diagnostic techniques and their management including the recent advances and the future perspective.     

Immunoelectron microscopical localization of immunoglobulins, secretory component and J chain in the human minor salivary glands

Localization of IgA, secretory component (SC) and J chain was investigated immunocytochemically in minor salivary glands of the lip and palate to define the mechanism involved in the transport of immunoglobulin A (slgA) into the saliva from the minor salivary glands. SC synthesis was detected in mucous acinar cells and ductal epithelial cells. Free SC is secreted into the saliva through secretory granules in the mucous acinar cells. Dimeric IgA containing J chain is translocated through these cells as slgA by a SC-medialed transport mechanism involving cytoplasmic vesicles.     

Immunoelectron microscopical localization of immunoglobulins, secretory component and J chain in the human minor salivary glands

Localization of IgA, secretory component (SC) and J chain was investigated immunocytochemically in minor salivary glands of the lip and palate to define the mechanism involved in the transport of immunoglobulin A (sIgA) into the saliva from the minor salivary glands. SC synthesis was detected in mucous acinar cells and ductal epithelial cells. Free SC is secreted into the saliva through secretory granules in the mucous acinar cells. Dimeric IgA containing J chain is translocated through these cells as sIgA by a SC-mediated transport mechanism involving cytoplasmic vesicles.