Akt Signaling Pathway Is Activated in the Minor Salivary Glands of Patients with Primary Sjögren's Syndrome.

Primary Sjögren's syndrome (pSS) is an autoimmune exocrinopathy of mainly the salivary and lacrimal glands associated with high prevalence of lymphoma. Akt is a phosphoinositide-dependent serine/threonine kinase, controlling numerous pathological processes, including oncogenesis and autoimmunity. Herein, we sought to examine its implication in pSS pathogenesis and related lymphomagenesis. The expression of the entire and activated forms of Akt (partially and fully activated: phosphorylated at threonine-308 (T308) and serine-473 (S473), respectively), and two of its substrates, the proline-rich Akt-substrate of 40 kDa (PRAS40) and FoxO1 transcription factor has been immunohistochemically examined in minor salivary glands (MSG) of pSS patients (n = 29; including 9 with pSS-associated lymphoma) and sicca-complaining controls (sicca-controls; n = 10). The entire and phosphorylated Akt, PRAS40, and FoxO1 molecules were strongly, uniformly expressed in the MSG epithelia and infiltrating mononuclear cells of pSS patients, but not sicca-controls. Morphometric analysis revealed that the staining intensity of the fully activated phospho-Akt-S473 in pSS patients (with or without lymphoma) was significantly higher than sicca-controls. Akt pathway activation was independent from the extent or proximity of infiltrates, as well as other disease features, including lymphoma. Our findings support that the Akt pathway is specifically activated in MSGs of pSS patients, revealing novel therapeutic targets.

Matrix metalloproteinase-7, -8, -9, -15, and -25 in minor salivary gland adenoid cystic carcinoma.

Knowledge on the role of matrix metalloproteinases (MMPs) in adenoid cystic carcinoma (ACC) is limited. MMPs are capable of degrading almost all extracellular and pericellular components to promote invasion and metastasis. This study aimed to evaluate the immunohistochemical expression of MMP-7, -8, -9, -15, and -25 in ACC and to relate the results with clinicopathological factors and survival. The study included 68 patients with minor salivary gland ACC treated at the Helsinki University Hospital (Helsinki, Finland) in 1974-2012. Samples from 52 patients were available, consisting of 44 primary tumours and eight recurrent tumours. We scored immunostaining of MMP-7, -8, -9, -15, and -25 and analysed the immunoscore against clinical and pathological parameters using statistical correlation test. MMP-9 immunoexpression in pseudocysts of ACC and in peritumoural inflammatory cells associated with better survival and fewer treatment failures. High tumoural MMP-7 and -25 associated with better survival. High tumoural MMP-15 associated with poorer survival and high tumoural MMP-9 with advanced stage and regional recurrences. Tumour cells did not show MMP-8 immunopositivity. These results suggest that MMP-9 may contribute to ACC carcinogenesis in different roles. MMP-7, -8, and -9 can stimulate signalling pathways that may promote tissue modulation and metastatic potential. MMP-15 and -25 may reflect prognosis.

Intraductal Papillary Mucinous Neoplasms of Minor Salivary Glands With AKT1 p.Glu17Lys Mutation.

The spectrum of low-grade intraductal papillary proliferations of the salivary glands is heterogenous, and reproducible morphologic diagnostic criteria have not yet been established. Recognized types are sialadenoma papilliferum, inverted ductal papilloma, and intraductal papilloma, but some lesions have been possibly included in the morphologic spectrum of cystadenoma or low-grade intraductal carcinomas. We herein present detailed morphologic, immunophenotypic, and genotypic features of 3 minor salivary gland neoplasms affecting 2 men (aged 65 and 71 y) and 1 woman (aged 78 y). They ranged in size from 1 to 2.5 cm. All tumors showed atypical papillary intraductal growth that presented either as uninodular/unicystic lesions (intraductal papilloma-like; n=2) or as a discontinuous growth along the ductal system in a manner similar to pancreatic intraductal papillary mucinous neoplasm (n=1). Variable cytologic and architectural atypia was observed, ranging from bland intraductal papilloma-like features, to areas mimicking atypical ductal hyperplasia and low-grade ductal carcinoma in situ of the breast. Amplicon-based massive parallel sequencing revealed an identical AKT1 p.Glu17Lys mutation in all 3 cases, but absence of concurring mutations in other genes of the RAS or PI3K pathway. This small series represents the first genetic study on salivary intraductal papillary neoplasms. Our cases showed significant variation in the degree of cytologic and architectural atypia, which overlaps with intraductal papillomas at the one end and with low-grade intraductal carcinoma at the other end of the spectrum, suggesting a disease continuum. As the full biological and morphologic characteristics of these ductal papillary lesions remain to be defined, the noncommitted term "intraductal papillary neoplasms" might be more appropriate. Our novel genetic findings mirror similar activating mutations of AKT1 and other PI3K pathway members in intraductal papillary lesions of the breast and anogenital glands.

Characterisation of Acetyl-CoA Thiolase: The First Enzyme in the Biosynthesis of Terpenic Sex Pheromone Components in the Labial Gland of Bombus terrestris.

Buff-tailed bumblebees, Bombus terrestris, use a male sex pheromone for premating communication. Its main component is a sesquiterpene, 2,3-dihydrofarnesol. This paper reports the isolation of a thiolase (acetyl-CoA thiolase, AACT_BT), the first enzyme involved in the biosynthetic pathway leading to formation of isoprenoids in the B. terrestris male sex pheromone. Characterisation of AACT_BT might contribute to a better understanding of pheromonogenesis in the labial gland of B. terrestris males. The protein was purified to apparent homogeneity by column chromatography with subsequent stepwise treatment. AACT_BT showed optimum acetyltransferase activity at pH 7.1 and was strongly inhibited by iodoacetamide. The enzyme migrated as a band with an apparent mass of 42.9 kDa on SDS-PAGE. MS analysis of an AACT_BT tryptic digest revealed high homology to representatives of the thiolase family. AACT_BT has 96 % amino acid sequence identity with the previously reported Bombus impatiens thiolase.

Abundant expression of mTOR kinase in salivary gland tumors - potentials as therapy target?

BACKGROUND: Salivary gland tumors constitute 3-6% of all head and neck neoplasms in adults. Because of limited advances made in the treatment of metastatic disease, the more important is the role of new therapeutic strategies, including molecular therapy. The mammalian target of rapamycin (mTOR) has recently been established as a therapeutic target for several drugs. MATERIAL: Evaluation of phospho-mTOR as a possible therapy target by patients with salivary gland tumors. Immunohistochemical semi-quantitative analyses of the expression of phospho-mTOR(Ser2448) were processed on a tissue microarray containing samples from more than 900 patients. For statistical analysis, contingency table and chi-squared test (likelihood) were used. RESULTS: We observed at least weak phospho-mTOR expression in 25.6-41.2% of all 4 histological adenoma and in 36.8-61.6% of all 11 histological carcinoma subtypes analyzed. No association was seen between phospho-mTOR expression and tumor grade in mucoepidermoid carcinomas. CONCLUSION: In conjunction with literature data providing the evidence for a functional role of mTOR in salivary gland tumors, we conclude that treatment with mTOR-antagonists might potentially also be efficient in wide variety of salivary gland carcinomas.

De novo biosynthesis of sexual pheromone in the labial gland of bumblebee males.

De novo biosynthesis of male sex pheromone from two bumblebee species (Bombus terrestris and Bombus lucorum) was studied by using in vitro incubations of labial glands (LGs) with radioactive [1,2-(14)C]acetate and deuterated [D(3)]acetate. The labeled substrate was incorporated into several types of compounds, such as terpenic alcohols, fatty acids, esters, and hydrocarbons. A similar incubation of [1,2-(14)C]acetate with fat bodies (FB) led to the formation of fatty acids, triacylglycerols (TAG), and hydrocarbons. To support the results from in vitro incubations, PCR analysis of fatty acid synthase (FAS) transcripts in LG and FB was performed. Relative quantification of FAS transcription levels revealed that the abundance of mRNA from the FAS gene is a function of the age of B. terrestris males. A comparison of the relative FAS mRNA gene transcription level in FB and LGs of B. terrestris and B. lucorum males proved that high biosynthetic activity takes place in the LGs of both species. Together, these results indicate that pheromone components are synthesized de novo in the LG.

Decreased salivary sulphotransferase activity correlated with inflammation and autoimmunity parameters in Sjogren's syndrome patients.

OBJECTIVES: To determine the expression and enzymatic activities of sulphotransferases involved in mucin hyposulphation in labial salivary glands (LSGs) from SS patients and to correlate sulphotransferase activity with clinical parameters such as secretion, inflammation and serology. METHODS: LSG from 31 SS patients and 31 control subjects were studied. Relative mRNA and protein levels of Gal3-O-sulphotransferases (Gal3STs) and ß1,3-galactosyltransferase-5 (ß3GalT5) were determined by quantitative RT-PCR and western blotting, respectively. Enzymatic activities were quantified using radioactively labelled donor substrates and specific acceptor substrates. Products were purified by chromatography. Spearman's correlation analysis was used to compare data. RESULTS: The levels of Gal3ST activity were significantly decreased in SS patients, without changes in mRNA and protein levels, while the enzymatic activities of glycosyltransferases involved in mucin glycosylation were similar in both groups. An inverse correlation was observed between Gal3ST activity and glandular function measured by scintigraphy, but not with unstimulated salivary flow. Gal3ST activity was inversely correlated with focus score, TNF-α levels and presence of the autoantibodies Ro/SS-A and La/SS-B. CONCLUSION: The decrease in sulphotransferase activity provides an explanation for mucin hyposulphation observed in the LSGs from SS patients. The decrease in Gal3STs activity was not a consequence of reduced gene expression, but probably due to alterations in the enzyme activity regulation. Interestingly, the levels of sulphotransferase activity detected correlated well with secretory function, inflammation and serology. Finally, we postulate that pro-inflammatory cytokines induced by autoantibodies, such as Ro/SS-A and La/SS-B in SS patients, may modulate Gal3ST activity, thereby altering mucin quality and leading to mouth dryness.

Expression of matrix metalloproteinases MMP-2, MMP-9 and their tissue inhibitors TIMP-1 and TIMP-2 in the epithelium and stroma of salivary gland pleomorphic adenomas.

AIMS: The balance between matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) is involved in the morphogenesis of normal salivary gland as well as in the mechanisms of tumour invasion and metastasis. The role of MMPs and TIMPs in pleomorphic adenoma has not been elucidated sufficiently. Our aim was to analyse the mRNA and protein expression of MMP-2, MMP-9, TIMP-1 and TIMP-2 in the epithelium and stroma of pleomorphic adenoma and to evaluate their roles. METHODS AND RESULTS: In each sample from six patients, cells from the epithelium and stroma were obtained by laser microdissection. The mRNA expression of MMPs and TIMPs was determined by real-time quantitative reverse transcriptase-polymerase chain reaction and protein expression was confirmed by immunohistochemistry. Results showed that mRNA expression of MMPs and TIMPs was significantly higher in stroma than in epithelium in most patients. MMPs and TIMPs were immunoreactive mainly in epithelium rather than in stroma. CONCLUSIONS: Our results provide preliminary evidence that stromal myoepithelium may be the primary source of MMPs and that the stroma has the potential to play a more important role than ductal epithelium in biological behaviour of pleomorphic adenomas. These findings seem worthy of further investigation.

alpha-Galactosidase activity in human saliva.

OBJECTIVE: The purpose of this study was to investigate whether alpha-galactosidase activity is present in whole and glandular saliva and whether alpha-galactosidase activity depends on blood type and secretor status. DESIGN: For the first experiments, 30 healthy participants (15 men, 15 women; mean age, 24.2+/-1.5 years) who were 10 A, 10 B, and 10 O blood type subjects were included. alpha-Galactosidase activity in unstimulated whole saliva (UWS) was assayed by using 4-methylumbelliferyl-alpha-d-galactopyranoside as a substrate. Total protein concentration was determined by bicinchoninic acid assay. The secretor status of the blood group antigens was determined by immunoblotting. alpha-Galactosidase activity in UWS according to gender, blood type, secretor status, sample clarification, and buffer was investigated. Daily variations of alpha-galactosidase activity and alpha-galactosidase isozyme activity were also investigated. For the second experiments, 10 healthy blood type B participants (5 men, 5 women; mean age, 27.0+/-2.7 years) were enrolled. alpha-Galactosidase activity in whole and glandular saliva was investigated. RESULTS: alpha-Galactosidase activity was detected in UWS and was mainly isozyme A activity. There was no difference in alpha-galactosidase activity according to gender, blood type, and secretor status. alpha-Galactosidase activity in UWS was higher in unclarified samples than in clarified ones and showed wide daily variations. alpha-Galactosidase activity in whole saliva was significantly higher than that in glandular saliva. CONCLUSIONS: alpha-Galactosidase activity which is mainly isozyme A activity was detected in human whole and glandular saliva. alpha-Galactosidase activity in UWS did not differ according to blood type and secretor status.

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.

Increased acinar damage of salivary glands of patients with Sjögren's syndrome is paralleled by simultaneous imbalance of matrix metalloproteinase 3/tissue inhibitor of metalloproteinases 1 and matrix metalloproteinase 9/tissue inhibitor of metalloproteinases 1 ratios.

OBJECTIVE: Previous findings in labial salivary glands (LSGs) from patients with Sjögren's syndrome (SS) suggest that increased activity and expression of matrix metalloproteinase 9 (MMP-9) and MMP-3 trigger the destruction of acinar structures in these glands. Tissue inhibitors of matrix metalloproteinases (TIMPs) tightly control MMP activity, and TIMP expression is an important modulator of effects attributed to MMPs. This study was undertaken to investigate the correlation between the balance of MMPs/TIMPs in the LSGs of SS patients and the degree of inflammatory infiltration and acinar structure integrity. METHODS: Three groups of SS patients classified according to focus score and residual tissue were studied. The expression of MMP-2, MMP-3, MMP-9, TIMP-1, and TIMP-2 was examined at the messenger RNA and protein levels. The ratio of MMP/TIMP expression (R value) was calculated. Focus score and acinar structure were evaluated by histologic analysis. RESULTS: In SS patients the MMP-3/TIMP-1 ratio was higher than 1 and the MMP-9/TIMP-1 ratio was much higher than 1 whereas the MMP-2/TIMP-2 ratio nearly equaled 1, suggesting elevated proteolytic activity due mainly to MMP-9. R values were independent of the focus score of inflammatory cells, but correlated well with the dramatic changes observed in morphologic integrity of acini, as revealed mainly by the lack of nuclear polarity. Acinar changes were more evident when R values for both MMP-9/TIMP-1 and MMP-3/TIMP-1 were higher. CONCLUSION: This study provides evidence that an altered balance between MMPs and their inhibitors is associated with acinar damage. Since salivary gland acinar cells express both MMPs and TIMPs, these cells may play an important role in extracellular matrix destruction and in the LSG pathophysiology in SS.

Lipolytic and esterolytic activities in posterior lingual glands of rat: a histochemical study.

Catalytic activities of lingual lipase were investigated by enzyme histochemistry in post-mortem tongues from male rats. Sections of fresh-frozen or formalin-calcium fixed tissue were incubated with naphthol-AS-nonanoate and alpha-naphthyl acetate substrate mixtures. The effects of pH level, sodium taurocholate activator and E600 inhibitor were also examined. The use of cryostat sections of tissues fixed in formalin-calcium and of nonanoate substrate within the range of pH 4.4-6.4, were optimal for localizing maximum reaction product, captured by Fast Blue BB, in acini and demilunes of the posterior deep and superficial lingual glands respectively. The reaction product corresponded with the distribution of secretory granules and failed to develop when taurocholate was omitted from the incubation medium. Similarly localized E600-resistant reaction product occurred with the acetate substrate and hexazotized New Fuchsin at pH 7.4, in the absence of taurocholate. Lipase and conventional esterase activities appear to be superimposed in posterior lingual glands of rat. The ability of their acini and demilunes to hydrolyse nonanoate substrate at an acidic pH optimum, when activated by sodium taurocholate, seems attributable to lipase destined for secretion into saliva--hence convenient for routine histochemical identification of the enzyme.

Secretion of carbonic anhydrase isoenzyme VI (CA VI) from human and rat lingual serous von Ebner's glands.

Salivary carbonic anhydrase VI (CA VI) appears to contribute to taste function by protecting taste receptor cells (TRCs) from apoptosis. The serous von Ebner's glands locating in the posterior tongue deliver their saliva into the bottom of the trenches surrounding the TRC-rich circumvallate and foliate papillae. Because these glands deliver their saliva directly into the immediate vicinity of TRCs, we investigated whether CA VI is secreted by the von Ebner's glands, using immunochemical techniques. The immunohistochemical results showed that CA VI is present in the serous acinar cells, ductal cells, and ductal content of von Ebner's glands and in the demilune and ductal cells plus ductal content of rat lingual mucous glands. More importantly, CA VI was also detected in taste buds and in the taste pores. Western blotting of saliva collected from the orifices of human von Ebner's glands and CAs purified from rat von Ebner's glands confirmed that CA VI is expressed in these glands and secreted to the bottom of the trenches surrounding the circumvallate and foliate papillae. These findings are consistent with the hypothesis that locally secreted CA VI is implicated in the paracrine modulation of taste function and TRC apoptosis. (J Histochem Cytochem 49:657-662, 2001)

Adrenoceptor-activated nitric oxide synthesis in salivary acinar cells.

We investigated the cellular regulation of nitric oxide synthase (NOS) activity in isolated acinar cells from rat parotid and human labial salivary glands, using the newly developed fluorescent nitric oxide (NO) indicator, DAF-2. We found that sympathetic stimulation with norepinephrine (NE) caused a strong increase in NO synthesis that was not seen after parasympathetic stimulation with acetylcholine. In rat parotid acinar cells, we furthermore investigated to which extent the NOS activity was dependent on the intracellular free Ca2+ concentration ([Ca2+]i) by simultaneously measuring NO synthesis and [Ca2+]i. It was found that a simple correlation between the rise in [Ca2+]i and the rate of NO production following NE stimulation does not exist, and studies in which [Ca2+]i was elevated by means of the Ca2+ ionophore, ionomycin, further established that even a very large rise in [Ca2+]i did not cause significant NO synthesis. We furthermore found that activating adrenoceptors with NE causes synthesis of cGMP by activating a guanylyl cyclase, and that an enhanced [cGMP] evoked by use of caged cGMP causes Ca2+ release from internal stores. Thus, upon sympathetic stimulation, salivary gland acini synthesize NO that, in addition to playing a role in controlling intracellular [Ca2+]i, also might play a role in retrograde signaling processes to the surrounding tissue.

Effect of 24 hours light on circadian rhythms of secretory enzymes and morphology of rat von Ebner's glands.

Von Ebner's glands of the rat are minor salivary serous glands in the posterior portion of the tongue. They secrete two digestive enzymes, lingual lipase and amylase. In this investigation, circadian rhythm in feeding was established under a normal 12 h light/12 h dark cycle, with the rats eating primarily during the dark period. At lights on, the size of the acinar cells and the area of the inclusive secretory granules, and the amount of digestive enzyme activity (lingual lipase and amylase) remaining in the gland was significantly less than in the mid-afternoon, after very little daylight food consumption. However, after 7 days of continuous light the circadian rhythm was altered: the food consumption during the normal night-time hours (5 p.m. to 8 a.m.) went from 88% of total 24 h food consumption to 45%, and during normal daylight hours (8 a.m. to 5 p.m.) from 12% to 55%. These changes were correlated with histometric findings of a near reversal of the areas of acinar cells and secretory granules of a.m. and p.m. samples under continuous light. Lingual lipase activity in the glands went from 35% under 12 h light to 61% under continuous light in the a.m. and from 65% to 39% in the p.m. Amylase activity also showed nearly a reversal in activity remaining in the gland, from 36% at 12 h light to 58% at 24 h light in the a.m. and 64% to 41% for the p.m. samples. These results indicate that the von Ebner's glands of the rat have a circadian rhythm of secretion and storage of secretory proteins that is subject to light entrainment similar to that seen in other exocrine glands such as the parotid and pancreas.

Chitinase in whole and glandular human salivas and in whole saliva of patients with periodontal inflammation.

In recent studies the existence of a chitinase in various mammals, like man, was described. The aim of the present study was to find out whether salivas of periodontally healthy and inflamed humans also contain chitinase activity. Chitinase activity, assayed with the substrate 4-methylumbelliferyl-beta-D-N,N',N"-triacetylchitotrioside, was shown to be present in human whole saliva, with an activity level and apparent molecular mass (35 kDa) that were comparable with those of the human serum enzyme. Both lysozyme and beta-N-acetylhexosaminidase could be separated from chitinase by means of Bio-Gel P-100 gel filtration chromatography. The enzyme was also present in glandular saliva of parotid, palatine, submandibular and sublingual glands. The chitinase activity was not of oral epithelial, bacterial or plaque bacterial origin and was not correlated with the activity of salivary amylase. A comparative study of whole salivas of periodontally healthy controls and gingivitis and periodontitis subjects showed that only in the case of periodontitis there was a significant increase of the specific chitinase activity. The latter enzyme showed a gel filtration pattern that was comparable with that of the enzyme from controls. The measured albumin levels in saliva and the absence of correlation between the chitinase activity levels in plasma and saliva from periodontitis patients indicated that the (increased) chitinase activities did not originate from blood leakage to the oral cavity.

Expression of metalloproteinase-2 (gelatinase A) in labial salivary glands of patients with Sjögren's syndrome with HTLV-I infection.

OBJECTIVE: To determine whether gelatinase A (MMP-2) plays a significant role in the pathogenesis of Sjögren's syndrome (SS) with or without HTLV-I infection. METHODS: We examined 24 patients with SS (14 HTLV-I-seropositive and 8 HTLV-I-seronegative). Labial salivary gland tissue samples were analysed immunohistochemically using anti-MMP-2 monoclonal antibodies. RESULTS: In normal salivary glands, MMP-2 expression was not detected. All biopsy samples of 8 SS patients with HTLV-I-associated myelopathy (HAM) and 3 of 6 HTLV-I-seropositive SS patients without manifestation of HAM stained positively for MMP-2. However, the other samples were negative for MMP-2. CONCLUSION: Our study showed the MMP-2 expression in labial salivary glands of HTLV-I seropositive SS patients, especially in all SS patients with HAM. The presence of MMP-2 in the salivary glands of these patients suggests that it may play a role in cellular infiltration and destruction in salivary glands of SS.

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 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 (von 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.

Secretion from minor salivary glands following ablation of the major salivary glands in rats.

Since minor salivary glands are tiny and dispersed, ductal cannulation cannot be used when studying their function. The present study was devised to develop a method of measuring minor salivary gland function by excision of the major glands. Female rats (230-280 g) were anaesthetized with sodium pentobarbital. Ablation of the submandibular, sublingual and parotid glands was performed through a sagittal neck incision. Sham-operated rats served as controls. Groups of sialadenectomized animals were investigated immediately and after 1 week, 2 weeks and 3 months. To study secretory function, the mouth was rinsed with 250 microl water in every 5 min and protein and amylase concentrations were measured. After an initial 50 min of basal secretion pilocarpine (1 mg/kg, i.p.) was given. Bilateral ablation of both submandibular, sublingual and parotid glands led to a moderate loss of body weight and a considerable increase in water intake. No other obvious abnormality was observed for periods up to 90 days following surgery. We deduce that the minor glands secrete approximately 14 % of protein and 1% of amylase in whole saliva Secretion is maintained even after 90 days following removal of the major glands. Surgical removal of the major salivary glands allows the secretory function of the minor glands in rats to be studied in vivo.

Immunolocalization of aromatase in human minor salivary glands of the lower lip with primary Sjögren's syndrome.

The enzyme aromatase is involved in the conversion of androgens to estrogens and in the modulation of various androgenic and estrogenic actions. Abnormalities of estrogen metabolism have been postulated to play roles in the development and/or pathophysiology of Sjögren's syndrome. In the present study, aromatase was immunolocalized in 75 cases of inflammatory disorders of human minor salivary glands of the lower lip. These included cases of primary Sjögren's syndrome (19 cases), of chronic sialadenitis (34 cases) and of mucous extravasation cysts (22 cases), in order to clarify the possible involvement of in situ estrogen production in primary Sjögren's syndrome. Aromatase immunoreactivity was detected in myoepithelial cells of acini and in interstitial cells adjacent to acini and ducts in 13/19 (68%) cases of primary Sjögren's syndrome. In contrast, aromatase expression was detected in only six of 34 (18%) cases of chronic sialadenitis and in seven of 22 (32%) cases of mucous extravasation cyst. These results suggest that increased aromatase expression in minor salivary glands with primary Sjögren's syndrome in premenopausal women may be involved in the biological features of primary Sjögren's syndrome through the production of estrogens in situ and possibly through the aggravation of the inflammatory reaction.