Involvement of expanded cytotoxic and proinflammatory CD28null T cells in primary Sjögren's syndrome

OBJECTIVE

The absence of CD28 is a feature of antigen-experienced, highly differentiated and aged T cells. The pathogenicity of CD28null T cells remains elusive in primary Sjögren's syndrome (pSS). Therefore, this study was performed to explore the characteristics of CD28null T cells in both peripheral blood and minor salivary glands (MSGs) of pSS patients.

METHODS

pSS patients and paired healthy controls (HCs) were enrolled. The phenotype of peripheral CD28null T cells was analyzed using flow cytometry. In vitro functional assays were performed to evaluate the cytotoxic and proinflammatory effects of peripheral CD28null T cells. In addition, polychromatic immunofluorescence staining was performed to investigate infiltrating CD28null T cells in MSGs.

RESULTS

A significant expansion of peripheral CD28null T cells was observed in pSS patients compared with HCs (p < 0.001), which were primarily CD8+CD28null T cells. The proportion of peripheral CD8+CD28null T cells moderately correlated with the erythrocyte sedimentation rate (r = 0.57, p < 0.01) and IgG levels (r = 0.44, p < 0.01). Peripheral CD28null T cells had stronger capacities to secrete granzyme B and perforin, but comparable capacities to secrete IFN-γ and TNF-α than their CD28+ counterparts. An abundant amount of cytotoxic and pro-inflammatory CD28null T cells was also found in MSGs. Moreover, a high expression of the chemokine receptor CXCR3 was found on peripheral and tissue-resident CD28null T cells, with its ligands CXCL9/10 abundantly present in MSGs.

CONCLUSION

Increasing CD28null T cells with strong cytotoxicity and proinflammatory effects were observed in both peripheral blood and MSGs from pSS patients. The precise mechanism of action and migration still needs further investigation.

Analysis of Hepatitis D Virus in Minor Salivary Gland of Sjögren's Disease

Hepatitis delta virus (HDV) has been detected in the minor salivary gland (MSG) tissue of Sjögren's disease (SjD) patients in the absence of a hepatitis B virus (HBV) coinfection. Previous research has shown that HDV antigen (HDAg) expression can trigger an SjD-like phenotype in vivo, demonstrating a potential cause-and-effect relationship. We hypothesize that if HDV plays a role in the development of SjD, then HDV profiles may be correlated with disease manifestations. This retrospective study characterized HDV in a cohort of 48 SjD MSG samples collected between 2014 and 2021. Analyses of HDAg expression, including cell type and subcellular localization, in situ hybridization of HDV RNA, and comparative analyses with associated SjD and viral hepatitis clinical features, were conducted. HDAg was detected in MSG acinar, ductal, myoepithelial, and adipose cells and localized with the nuclei, cytoplasm, and mitochondria. In situ hybridization detected HDV genomic RNA localization in the MSG nuclei. A significant negative correlation was found between HDAg intensity and focal lymphocytic inflammation and in patients with both anti-SSA/Ro-52 and anti-SSA/Ro-60. In analyzing autoimmune disease comorbidities with SjD, it was found that SjD patients diagnosed with autoimmune thyroiditis and/or hypothyroidism were significantly more represented in the high HDAg intensity group compared to the negative and moderate HDAg intensity groups. No significant associations were detected between MSG-localized HDAg and liver enzymes or an evident HBV coinfection. This study has further confirmed that there is a nonhepatic reservoir for chronic HDV persistence in SjD-affected salivary gland tissue in a third independent SjD patient cohort. In addition, this study describes the unique colocalization of HDAg with mitochondria. The detection of HDV antigen and sequence within SjD-affected salivary gland tissue, and in the absence of an evident current or past HBV coinfection, warrants further investigation.

Connexin Expression in Human Minor Salivary Glands: An Immunohistochemical Microscopy Study

Connexins (Cxs) are transmembrane proteins involved in the formation of hemichannels and gap junctions (GJs). GJs are involved in various physiological functions, including secretion in glandular tissue. It has been demonstrated that Cx26, Cx32, and Cx43 are mainly expressed in glands, but no data are available in human salivary glands to date. The aim of our study was to investigate the presence and the localization of Cxs in human minor labial salivary glands. Immunofluorescence and immunoelectron microscopy were employed to evaluate the Cx26, Cx32, and Cx43 protein in human labial salivary gland biopsies (hLSGBs). RT-PCR was also used to detect their mRNA expression. Cx expression was found at both the mRNA and protein levels in all hLSGBs analysed. Cxs were observed at the level of the duct and acinar cells, as well as in myoepithelial cells. The localization of the three Cx types was very similar, suggesting colocalization of these Cxs in the same connexons. These results demonstrated the presence of Cxs in human salivary glands for the first time. Moreover, the few samples with primary Sjögren’s Syndrome analysed only by immunofluorescence showed an alteration of the Cx expression, indicating that these proteins could be involved in salivary gland dysfunctions.

A Link Between Mitochondrial Dysfunction and the Immune Microenvironment of Salivary Glands in Primary Sjogren’s Syndrome

Background

Primary Sjogren’s syndrome (pSS) is a slowly progressive, inflammatory autoimmune disease characterized by lymphocytic infiltration into salivary and lacrimal glands. It becomes more recognized that morphology alterations of epithelial mitochondria are involved in altered cellular bioenergetics in pSS patients. The integrated analysis of the mitochondrial role in the pathogenesis and aberrant immune microenvironment in pSS remains unknown.

Methods

The mitochondria-related genes and gene expression data were downloaded from the MitoMiner, MitoCarta, and NCBI GEO databases. We performed novel transcriptomic analysis and constructed a network between the mitochondrial function and immune microenvironment in pSS-salivary glands by computer-aided algorithms. Subsequently, real-time PCR was performed in clinical samples in order to validate the bioinformatics results. Histological staining and transmission electron microscopy (TEM) were further studied on labial salivary gland samples of non-pSS and pSS patients characterized for mitochondria-related phenotypic observation in the different stages of the disease.

Results

The bioinformatic analysis revealed that the expression of several mitochondria-related genes was altered in pSS. Quantitative real-time PCR showed that four hub genes, CD38, CMPK2, TBC1D9, and PYCR1, were differentially expressed in the pSS clinical samples. These hub genes were associated with the degree of immune cell infiltration in salivary glands, the mitochondrial respiratory chain complexes, mitochondrial metabolic pathway in gluconeogenesis, TCA cycle, and pyruvate/ketone/lipid/amino acid metabolism in pSS. Clinical data revealed that the gene expression of fission (Fis1, DRP1, and MFF) and fusion (MFN1, MFN2, and OPA1) was downregulated in pSS samples, consistent with the results from the public validation database. As the disease progressed, cytochrome c and Bcl-2 proteins were regionally distributed in salivary glands from pSS patients. TEM revealed cytoplasmic lipid droplets and progressively swollen mitochondria in salivary epithelial cells.

Conclusion

Our study revealed cross talk between mitochondrial dysfunction and the immune microenvironment in salivary glands of pSS patients, which may provide important insights into SS clinical management based on modulation of mitochondrial function.

Specialized pro-resolving receptors are expressed in salivary glands with Sjögren's syndrome

Our previous studies demonstrated that resolvin D1 (RvD1) and its aspirin-trigged (AT) form AT-RvD1, are effective in decreasing inflammation while restoring saliva flow rates in a Sjögren's syndrome (SS)-like mouse model before and after disease onset. Resolvins are specialized pro-resolving mediators (SPM) that actively regulate inflammation. However, we only have extensive data within the salivary glands for RvD1 and AT-RvD1, both of which bind to the receptor ALX/FPR2. As such, the presence of other SPM receptors is unknown within salivary glands. Therefore, the goal of this study was to determine the expression of SPM receptors in non-SS and SS patients. For this purpose, six human minor salivary glands from female subjects were analyzed by H&E using the Chisholm and Mason classification to determine the degree of lymphocytic infiltration. Next, confocal immunofluorescence analysis was performed to determine the presence and distribution of different SPM receptors in mucous acini and striated ducts. We observed diffuse presence of lymphocytic infiltration and clinical data were consistent with SS diagnosis in three patients. Moreover, confocal immunofluorescence analysis indicated the presence of the receptors ALX/FPR2, BLT1 and CMKLR1 in the mucous acini and striated ducts of both non-SS and SS patients. GPR32 was absent in SS and non-SS minor salivary glands. In summary, our results showed that various SPM receptors are expressed in non-SS and SS minor salivary glands, all of which may pose as potential targets for promoting pro-epithelial and anti-inflammatory/pro-resolution signaling on SS patients.

Increased Expression of the lncRNA NRON Along With NFATc1/PIM-1 in Labial Salivary Glands of Sjögren's Syndrome Patients

The aim of our study was to analyze the expressions of nuclear factor of activated T cells (NFAT)-related substances including long noncoding RNA NRON which participates in pathophysiology of Sjögren's syndrome (SS), and to assess the histologic findings in individuals with SS. In this study, the expressions of NRON, NFATc1, CD3/CD4, and proviral integration site for Moloney murine leukemia virus (PIM)-1 were examined by in situ hybridization, immunohistochemical analysis, and immunofluorescence in labial salivary glands (LSGs) obtained from 16 patients with SS and five controls. The microcell count method has been applied to calculate the NFATc1-positive area/infiltrating cell area in LSGs, and we compared those results to the infiltrating cell area, focus score, serum immunoglobulin G, and the European League Against Rheumatism Sjögren's Syndrome Disease Activity Index. The NRON expression in the nuclei of cell-infiltration lesions of the SS patients were prominent. The NFATc1 expression was strong in the cytoplasm of infiltrating mononuclear cells and weak in ducts of both SS and controls. In SS, the NFATc1-positive area/infiltrating cell area was positively correlated with the infiltrating cell area and focus score. CD3/CD4 was expressed in infiltrating mononuclear cells, and PIM-1 colocalized with NFATc1 in the cytoplasm. These results suggest NRON along with NFATc1/PIM-1 in SS LSGs might participate in SS pathophysiology.

Minor salivary glands: Clinical, histological and immunohistochemical features of common and less common pathologies

Hundreds of minor salivary glands (MiSGs) are scattered in the oral cavity located at the submucosa layer. Beside their role in the oral cavity lubrication and immunity defence system, MiSGs are beneficial tissue source for diagnosing oral and non-oral related diseases. The advantage of MiSGs as a diagnostic tool reside on their fairly simple excisional procedure on one hand and negligible impact of the normal secretion capability of the salivary gland system on the other hand. The review focuses on pathologies related to developmental, reactive, metabolic, inflammatory and immunologic conditions, Iatrogenic causes and other undefined causes.

Different operators and histologic techniques in the assessment of germinal center-like structures in primary Sjögren's syndrome minor salivary glands

Objective

A standardization of minor salivary gland (MSG) histopathology in primary Sjögren’s syndrome (pSS) has been recently proposed. Although there is strong agreement that germinal center (GC)-like structures should be routinely identified, due to their prognostic value, a consensus regarding the best protocol is still lacking. Aim of this study was to compare the performance of different histological techniques and operators to identify GC-like structures in pSS MSGs. MSG biopsies from 50 pSS patients were studied.

Methods

Three blinded operators (one pathologist and two rheumatologists with different years of experience in pSS MSG assessment) assessed 50 MSGs of which one slide was stained with haematoxylin and eosin (H&E) and consecutive slides were processed to investigate CD3/CD20, CD21 and Bcl-6 expression.

Results

By assessing 225 foci, the best agreement was between H&E-stained sections evaluated by the rheumatologist with more years of experience in pSS MSG assessment and CD3/CD20 segregation. In the foci with CD21 positivity, the agreement further increased. Bcl-6^- foci could display a GC, detected with other staining, but not vice versa.

Conclusion

GC assessment on H&E-stained sections should be performed with caution, being operator-dependent. The combination of H&E with CD3/CD20 and CD21 staining should be recommended as it is reliable, feasible, able to overcome the bias of operator experience and easily transferrable into routine practice.

Association of high 5-hydroxymethylcytosine levels with Ten Eleven Translocation 2 overexpression and inflammation in Sjögren's syndrome patients

Here, we determined the 5-hydroxymethylcytosine (5hmC), 5-methylcytosine (5mC), Ten Eleven Translocation (TETs), and DNA methyltransferases (DNMTs) levels in epithelial and inflammatory cells of labial salivary glands (LSG) from Sjögren's syndrome (SS)-patients and the effect of cytokines on HSG cells. LSG from SS-patients, controls and HSG cells incubated with cytokines were analysed. Levels of 5mC, 5hmC, DNMTs, TET2 and MeCP2 were assessed by immunofluorescence. In epithelial cells from SS-patients, an increase in TET2, 5hmC and a decrease in 5mC and MeCP2 were observed, additionally, high levels of 5mC and DNMTs and low levels of 5hmC were detected in inflammatory cells. Cytokines increased TET2 and 5hmC and decreased 5mC levels. Considering that the TET2 gene.promoter contains response elements for transcription factors activated by cytokines, together to in vitro results suggest that changes in DNA hydroxymethylation, resulting from altered levels of TET2 are likely to be relevant in the Sjögren's syndrome etiopathogenesis.

Increased expression of interferon-λ in minor salivary glands of patients with primary Sjögren's syndrome and its synergic effect with interferon-α on salivary gland epithelial cells

OBJECTIVES

To investigate the expressions of interferon (IFN)-λs and their receptor, IL28RA, in minor salivary glands (MSG) of pSS patients and their effects on the salivary gland cells.

METHODS

The expressions of IFN-λs and IL28RA were evaluated in MSG by immunohistochemistry in 15 patients with pSS and in 5 patients with non-SS sicca. Poly(I:C)-induced IL-28A and IL-29 expressions were determined in immortalized human salivary gland acinar (NS-SV-AC) and ductal (NS-SV-DC) cell lines. We assessed the effect of IFN-λs on the expressions of typical interferon-inducible genes, B-cell activating factor (BAFF) and CXCL10, and the synergistic effect of IL-29 and type I or II IFN on their expressions. The serum IL-29 levels were measured in 44 patients with pSS and 22 healthy controls.

RESULTS

IFN-λs expression was significantly higher in MSG from pSS than from non-SS sicca controls. Poly(I:C) treatment led to the induction of IL-28A and IL-29 in the salivary gland cell lines. In the NS-SV-DC cells, IFN-λ significantly increased the levels of BAFF and CXCL10 in a time and dose-dependent manner. Moreover, there was a synergistic effect between IL-29 and IFN-α in the induction of BAFF and CXCL10 expressions by prolonged STAT1 phosphorylation. However, the serum IL-29 levels were not significantly higher in pSS patients than in healthy controls.

CONCLUSIONS

Our results suggest the possibility for IFN-λ to play a role by participating local inflammation in the salivary glands of pSS through direct and indirect regulations of the expressions of BAFF and CXCL10 in salivary gland epithelium.

Levels of EGF and VEGF in patients with primary and secondary Sjögren's syndrome

BACKGROUND

Aberrant angiogenesis plays a role in the pathogenesis of Sjögren's syndrome (SS).

OBJECTIVES

The aim of this study was to compare the levels of vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) in stimulatory parotid saliva and in serum in healthy subjects (HS), patients with primary SS (pSS) and secondary SS (sSS) and to evaluate the expression of EGF, proangiogenic VEGF165 and antiangiogenic VEGF165 b mRNA isoforms. Additionally, we determined the salivary levels of serine/arginine splicing factor (SRSF1), which regulates VEGF165 and VEGF165 b expression.

MATERIAL AND METHODS

The study comprised 34 women (16 with pSS and 18 with sSS) and healthy subjects for blood and saliva sampling. EGF and VEGF levels in saliva and serum and salivary SRSF1 levels were determined by enzyme-linked immunosorbent assay (ELISA). The expression of VEGF165 , VEGF165 b and EGF in peripheral blood mononuclear cells (PBMC) was evaluated by quantitative polymerase chain reaction (qPCR).

RESULTS

There were no differences in the levels of EGF, VEGF, SRSF1 and in the expression of the EGF, VEGF165 and VEGF165 b between HS and SS patients, or between pSS and sSS patients. The salivary levels of VEGF165 and EGF were significantly higher in pSS, sSS and HS than serum levels. Levels of SRSF1 correlated positively with VEGF and EGF levels. Levels of EGF, VEGF and SRSF1 correlated with each other.

CONCLUSIONS

The balance of VEGF isoforms is not disturbed in SS. Saliva is more sensitive for the detection of EGF and VEGF than serum, but salivary levels of those proteins are not representative for SS.

Cribriform adenocarcinoma of the minor salivary gland arising in the tonsil with metastasis to a cervical lymph node: A case report with description of fine needle aspiration cytology

Cribriform adenocarcinoma of minor salivary gland (CAMSG) is a rare tumor of the head and neck. We report a case of a 70-year-old female who presented with a 4-5-month history of a left neck mass. CT scan of the neck showed a left neck mass just inferior to the angle of the mandible and left tonsillar prominence. Fine-needle aspiration (FNA) of the neck mass showed epithelial groups with focal cribriform architecture. The cells had round to oval nuclei and fine chromatin. The background contained scattered lymphocytes. A preliminary diagnosis of low grade adenocarcinoma with cribriform features metastatic to a lymph node was made. Subsequent biopsy of the tonsil mass showed a tumor with a combination of tubular, solid, and papillary architecture containing round to ovoid nuclei with very fine chromatin, consistent with cribriform adenocarcinoma of the minor salivary gland. Cribriform adenocarcinoma of minor salivary gland has a documented tendency to metastasize to cervical lymph nodes. Since this neoplasm can cytologically and histologically resemble other neoplasms of the head and neck, including polymorphous low-grade adenocarcinoma (PLGA), papillary thyroid carcinoma (PTC), and occasionally adenoid cystic carcinoma, being aware of and familiar with the cytologic features of CAMSG on FNA smears is important for patient management. Diagn. Cytopathol. 2017;45:468-471. © 2017 Wiley Periodicals, Inc.

Study of microRNAs (miRNAs) that are predicted to target the autoantigens Ro/SSA and La/SSB in primary Sjögren's Syndrome

The elevated tissue expression of Ro/SSA and La/SSB autoantigens appears to be crucial for the generation and perpetuation of autoimmune humoral responses against these autoantigens in Sjögren's syndrome (SS). The mechanisms that govern their expression are not known. miRNAs, the post-transcriptional regulators of gene expression, might be implicated. We have identified previously the miRNAs let7b, miR16, miR181a, miR200b-3p, miR200b-5p, miR223 and miR483-5p that are predicted to target Ro/SSA [Ro52/tripartite motif-containing protein 21 (TRIM21), Ro60/TROVE domain family, member 2 (TROVE2)] and La/SSB mRNAs. To study possible associations with autoantigen mRNA expression and disease features, their expression was investigated in minor salivary gland (MSG) tissues, peripheral blood mononuclear cells (PBMC) and long-term cultured non-neoplastic salivary gland epithelial cells (SGEC) from 29 SS patients (20 of 29 positive for autoantibodies to Ro/SSA and La/SSB) and 24 sicca-complaining controls. The levels of miR16 were up-regulated in MSGs, miR200b-3p in SGECs and miR223 and miR483-5p in PBMCs of SS patients compared to sicca-complaining controls. The MSG levels of let7b, miR16, miR181a, miR223 and miR483-5p were correlated positively with Ro52/TRIM21-mRNA. miR181a and miR200b-3p were correlated negatively with Ro52/TRIM21 and Ro60/TROVE2 mRNAs in SGECs, respectively, whereas let7b, miR200b-5p and miR223 associated with La/SSB-mRNA. In PBMCs, let7b, miR16, miR181a and miR483-5p were correlated with Ro52/TRIM21, whereas let7b, miR16 and miR181a were also associated with La/SSB-mRNA expression. Significantly lower miR200b-5p levels were expressed in SS patients with mucosa-associated lymphoid tissue (MALT) lymphoma compared to those without. Our findings indicate that miR16, miR200b-3p, miR223 and miR483-5p are deregulated in SS, but the exact role of this deregulation in disease pathogenesis and autoantigen expression needs to be elucidated.

Endoplasmic reticulum stress causes autophagy and apoptosis leading to cellular redistribution of the autoantigens Ro/Sjögren's syndrome-related antigen A (SSA) and La/SSB in salivary gland epithelial cells

The aim of this study was to examine the levels of endoplasmic reticulum (ER) stress in minor salivary glands, to investigate the interplay between ER stress-induced autophagy and apoptosis in human salivary gland (HSG) cells and to test the effect of ER stress-induced apoptosis on the cellular redistribution of the two major Sjögren's syndrome (SS) autoantigens Ro/Sjögren's syndrome-related antigen A (SSA) and La/Sjögren's syndrome-related antigen B (SSB). Minor salivary gland biopsies from SS patients and sicca controls were examined by immunohistochemistry for the expression of 78 kDa glucose-regulated protein/binding immunoglobulin protein (GRP78/BiP) as an indicator of unfolded protein response (UPR). HSG cells were treated with thapsigargin (TG) and cell viability, autophagy and apoptosis were assessed. Immunoblot was applied to detect the conversion of LC3I to LC3II and the protein levels of GRP78/BiP and X-box binding protein-1 (XBP-1). Apoptosis was evaluated by a single-stranded DNA enzyme-linked immunosorbent assay (ELISA). Ro/SSA and La/SSB localization was visualized using immunofluorescence. GRP78/BiP was expressed by acinar and ductal epithelial cells in salivary glands of patients and sicca controls. TG treatment induced autophagy, as indicated by enhanced protein expression of LC3II. The protein levels of UPR marker XBP-1 were increased after TG treatment, while GRP78/BiP levels were decreased. TG treatment resulted in induction of HSG apoptosis. Ro/SSA and La/SSB autoantigens were localized predominantly to the cytoplasm in resting cells, while they were redistributed to cell membrane and blebs in the apoptotic cells. In conclusion, ER stress is activated in minor salivary gland epithelial cells from SS patients and controls. ER stress-induced apoptosis in HSG cells leads to cell surface and apoptotic blebs relocalization of Ro/SSA and La/SSB autoantigens.

Characteristics of the saliva flow rates of minor salivary glands in healthy people

OBJECTIVES

To investigate the normal range and characteristics of saliva secretion in the minor salivary glands (MSGs).

DESIGN

The flow rates of MSGs were measured in 4 anatomical locations of oral mucosa, and the relationship between MSG flow rates and whole saliva flow rates were assessed in 300 healthy subjects stratified by age and sex. An additional 30 young females were further evaluated for flow symmetry, effects of stimulation, circadian effects in MSGs, and the relationship with the flow rates of major salivary glands.

RESULTS

(1) The mean saliva flow rates were 2.10 ± 0.66 (lower labial glands), 2.14 ± 0.62 (upper labial glands), 2.88 ± 0.72 (buccal glands) and 2.15 ± 0.51 (palatal glands) μl/min/cm(2), respectively. The flow rate of buccal glands was significantly higher than the rates of SMGs in other locations (P < 0.01). (2) 5-year-old children had the lowest MSG flow rates (P < 0.0001) while the 10-14-year-old group had the highest (P < 0.001). (3) MSG flow rates were independent of sex (P > 0.05), right vs. left (P > 0.05), and citric acid (2.5%) stimulation (P > 0.05). (4) Only labial MSG displayed a significant secretory circadian rhythm with the highest rate in the evening (P < 0.05). (5) A weak correlation was found between the flow rate of palatal glands and that of unstimulated whole saliva (r = 0.195, P = 0.007).

CONCLUSIONS

Our findings provide a reference for functional evaluation of MSGs and for donor site selection of MSG transplantation for treatment of severe dry eye syndrome.

Neovascularization is prominent in the chronic inflammatory lesions of Sjögren's syndrome

Angiogenesis is a common finding in chronic inflammatory diseases; however, its role in Sjögren's syndrome (SS) remains to be elucidated. Previous SS studies have demonstrated an increase in VEGF-A/VEGFR-2 system expression in minor salivary gland (MSG) biopsies from patients with SS, but differences in the new blood vessel formation between the different grades of disease severity have not been reported. Therefore, experiments were performed to demonstrate angiogenesis during different phases of primary SS (pSS) and to define the relationship between the microvessel density (MVD), macrophage infiltration and histiocyte distribution in SS MSG inflammatory lesions. In this series of experiments, immunohistochemistry was used to examine angiogenesis in serial sections of pSS MSG. Patients with pSS were classified accordingly with the grade of inflammatory lesions as I = low-grade (low focus score of 1 or 2), II = intermediate-grade (focus score of 3–6) and III = extensive inflammation in the MSG (high focus score of 12). Histological examination demonstrated that the MVD increased with the severity of the inflammatory lesions, and in addition, we found an increased infiltration of inflammatory and pro-angiogenic cells.These findings reveal that angiogenesis is intimately involved in the progression of pSS, may be central to the propagation of the chronic immune response observed in pSS and could represent a novel potential biomarker of pSS disease activity.

Expression of resolvin D1 biosynthetic pathways in salivary epithelium

Resolvins are potent anti-inflammatory mediators derived from ω-3 fatty acids. Results from our previous studies indicated that resolvin D1 (RvD1) blocks pro-inflammatory responses in salivary glands. Furthermore, RvD1 enhances salivary epithelial integrity, demonstrating its potential use for the restoration of salivary gland function in Sjögren's syndrome (SS). We investigated whether the RvD1 biosynthetic machinery (e.g., cytosolic phospholipase A2, calcium-independent phospholipase A2, 12/15 and 5-lipoxygenase) is expressed in mouse submandibular glands (mSMG), using qPCR and Western blot analyses. Additionally, we determined the localization of RvD1 biosynthetic machinery in mSMG and human minor salivary glands (hMSG), with and without SS, using confocal microscopy. Finally, we measured RvD1 levels in cell supernatants from mSMG cell cultures and freshly isolated mSMG cells, with and without SS, using ELISA. Our results indicate that: (1) RvD1 machinery is expressed in mouse and human salivary glands; (2) polar distribution of RvD1 biosynthetic machinery is lost in hMSG with SS; (3) RvD1 levels in mSMG cell culture supernatants increased with time; and (4) RvD1 levels in mSMG cell supernatants, with and without SS, were similar. These studies demonstrate that the RvD1 biosynthesis machinery is expressed and functional in salivary glands with and without SS.

[Microscopic Raman spectral characteristics and diagnostic value of pathological lip minor salivary glands affected in primary Sjögren's syndrome]

OBJECTIVE

To investigate the Raman spectral characteristics of the pathological lip minor salivary glands affected in primary Sjögren's syndrome.

METHODS

Thirty pathological samples and 30 normal samples were collected in this study. The samples were examined by Raman microscope.Support vector machine(SVM) was employed to analyze the data and establish the classification model.

RESULTS

The spectra of pathological tissues was different from the controls in proteins, nucleic acids, lipids and glycogen skeleton. The sensitivity, specificity and accuracy of the model established by SVM on the training sets were all 92.0% (92/100), but the sensitivity, specificity and accuracy of the model established by SVM on the testing sets were 69.2% (37/53), 100.0% (37/37) and 82.0% (73/89) respectively.

CONCLUSIONS

There was significant difference in Raman spectra between the pathological and normal lip salivary glands, and the classification model established by SVM could discriminate the pathological glands from the normal ones.

Cribriform adenocarcinoma of the tongue and minor salivary glands: a review

Cribriform adenocarcinoma of the tongue and minor salivary glands (CATMSG) is a tumor occurring mostly, but not exclusively, in the base of the tongue. Other locations are minor salivary glands of the oral cavity. Histopathologically, CATMSG resembles papillary carcinoma of the thyroid gland. It usually reveals a solid growth devoid of colloid, and eosinophilic material present in follicular areas is rather pale in contrast to metastatic foci seen in papillary thyroid carcinoma that shows typical deeply eosinophilic colloid with "moth-eaten peripheries" and cystic configuration. In addition, giant multinucleated cells are not observed in CATMSG and psammoma bodies are found only exceptionally. Unlike papillary thyroid carcinoma, CATMSG is composed of hybrid secretory-myoepithelial cells. Most importantly, CATMSG is consistently negative with both thyroglobulin and TTF-1. CATMSG is a distinct tumor entity that also differs from polymorphous low-grade adenocarcinoma by location, cytology, histological architecture, and behavior, with frequent metastases at the time of presentation. Paradoxically, early metastatic disease seen in most cases of CATMSG is associated with an indolent behavior. It makes CATMSG a unique neoplasm among all low-grade salivary gland tumors.

Electron microscopic immunogold localization of salivary mucin MUC5B in human buccal and palatal glands

In recent years, minor salivary glands, due to their involvement in the health and homeostasis of the oral cavity, have been the focus of several research investigations. Despite the fact that a considerable amount of data has been collected, many aspects of their functional features, including the secretory components they produce, remain to be ascertained. In this study we have analyzed the ultrastructural distribution of the MUC5B mucin in human palatal and buccal glands by means of post-embedding immunoelectron microscopy. Thin sections of normal human buccal and palatal glands obtained at surgery, were treated with polyclonal antibodies to human salivary MUC5B. Intense MUC5B reactivity was observed in the secretory granules of mucous cells of all glands examined. The present results provide new data regarding the secretory pattern of MUC5B in human buccal and palatal glands, indicating their significant contribution to the maintenance of the mucous biofilm that protects buccal and palatal mucosal areas.

On minor salivary gland secretion in children, adolescents and adults

The minor salivary glands are of great importance for maintenance of homeostasis in the oral cavity. These glands continuously secrete substances which lubricate and protect the oral tissues, contributing to comfort and health. The minor salivary glands contribute approximately 7-8 per cent of the total volume of saliva. Flow rate and composition seem to vary according to anatomical location. Current knowledge about the minor salivary glands is derived primarily from studies on adults. The overall aim of this thesis was to study age-related changes in minor gland saliva, from childhood to adulthood. By increasing the knowledge of minor gland secretion, we hopefully better understand how different mucosal locations are lubricated and protected in individuals of different ages and various health statuses. The project comprises four papers. In Paper I, the flow rate and numerical density of the labial and buccal minor glands of pre-school children, adolescents and adults were investigated. Saliva was collected on filter paper discs and the flow rate was measured by the Periotron-method. The numerical density was assessed by PAS-staining.

KEY FINDINGS

The flow rate of the buccal glands was significantly lower in children than in adults and the number of labial glands was significantly higher in children than in the other age-groups. In Paper II, the composition of minor gland saliva of the three age groups (Paper I) was analysed (by ELISA-technique), with reference to the mucins MUC5B and MUC7, representing some of the major components of innate salivary immunity.

KEY FINDINGS

Children did not differ from adolescents and adults with respect to MUC5B content in labial gland saliva, but had less MUC7 than the adults. In the buccal gland saliva, detectable amounts of the mucins were found in only a few of the participants. In Paper III, the content of the adaptive immune component (salivary IgA) in minor gland saliva of pre-school children, adolescents and adults was measured by the ELISA technique. The salivary IgA-concentration in whole saliva of the three age-groups was also estimated.

KEY FINDINGS

The IgA-concentration was significantly lower in the labial glands and the whole saliva of the children than in the adults. In Paper IV, age-dependent differences of other innate components were studied in pre-school children, adolescents and adults, by analysing the amount of glycoprotein 340 (gp-340) in minor gland and whole saliva, using the ELISA technique. The content of sialic acid, a common terminal structure of glycoproteins, was analysed using the ELLA technique.

KEY FINDINGS

With respect to minor gland saliva, no differences were disclosed among pre-school children, adolescents and adults. However, the gp-340 content of whole saliva was significantly higher in the children than in the adults. The above investigations of properties of minor salivary glands in children, adolescents and adults seems to be the first to present data on age-dependent variations in gland density and secretions from healthy individuals. The results show high gland density, mature innate immunity and an ongoing maturation of adaptive immunity in the saliva of children. The report provides a reference for further comparative studies on minor gland saliva of younger individuals in health and disease.

Ultrastructural localization of salivary mucins MUC5B and MUC7 in human labial glands

As a result of their presence throughout the mouth in the submucosa or between muscle fibers, minor salivary glands secrete directly and continuously into the oral cavity, providing mucosal surfaces with highly glycosylated proteins that are active in bacterial aggregation and in oral tissue lubrication. In this study, we investigated the ultrastructural localization of the MUC5B and MUC7 mucins in human labial glands by means of a postembedding immunogold technique. Thin sections of normal human labial glands, obtained during surgery, were incubated with polyclonal antibodies to human salivary mucins MUC5B and MUC7, and then with gold-labeled secondary antibodies. Specific MUC5B reactivity was found in the secretory granules of mucous cells of all glands examined, and was associated with the luminal membrane of duct cells. MUC7 labeling was observed in the granules of both mucous and seromucous secretory cells of the glandular parenchyma. Quantitative analyses demonstrated that seromucous granules have higher immunogold labeling densities for MUC7 than mucous granules. Our immunohistochemical data extend the results of previous light microscopic studies of MUC5B and MUC7 localizations, pointing out the significant contribution of human labial glands in the secretion process of these two mucins.

[Expression of SSA antigen epitopes in minor salivary glands from patients with primary Sjögren's syndrome]

OBJECTIVE

To investigate the correlation between the differential expression of 60 000 SSA epitopes in minor salivary glands (MSG) from patients with primary Sjögren's syndrome (pSS) and glandular inflammation.

METHODS

The screening and soluble expression of single-chain fragment V monoclonal antibodies (Scfv McAb) against SSA antigen epitopes (P1: 480 - 494, P2: 310 - 323 and P3: 230 - 241) were performed by phagemid antibody expression system. The expression of epitopes was detected by immunohistochemical assay (IH) in minor salivary glands from these patients. The correlation between epitopes expression and glandular inflammation was analyzed quantitatively.

RESULTS

Immunohistochemical assay of MSG with McAb against P1-P3 epitopes showed that the epithelial cells of glandular tubes and striated duct were stained in membrane and cytoplasm. The expression of P1 epitope was higher than the other two in grading score (chi(2) = 12.94, P < 0.01). And a positive correlation was found between the extent of glandular infiltration and the grade of P1 epitope expression (t = 2.27, P < 0.05) but not with P2 or P3 epitope.

CONCLUSION

Aberrant redistribution of intracellular SSA antigen epitopes onto the cell membrane of involved cells may break the immune tolerance and thus induce the production of pathogenic autoantibodies involved in triggering and maintaining the tissue-specific autoimmune response in pSS MSG. A significantly high membranous expression of P1 and a positive correlation between P1 and the inflammation of MSG suggest that P1 may be the dominant determinant of the antigen-driven immune response in pSS.

Salivary resistin reflects local inflammation in Sjögren's syndrome

OBJECTIVE

To assess the role of resistin in primary Sjögren's syndrome (pSS) and its relation to local inflammation.

METHODS

Blood and saliva were collected from 37 patients with pSS (duration of symptoms 12.6+/-1 yrs) and 32 healthy controls. Expression of resistin in salivary glands was visualized immunohistologically, and levels of resistin were detected by ELISA. Levels of resistin were evaluated at baseline and following oral dehydroepiandrosterone (DHEA) treatment (50 mg/day). The effect of DHEA treatment on the secretion of resistin was assessed in vitro in human leukocytes after challenge with insulin and lipopolysaccharide.

RESULTS

Levels of resistin in saliva were significantly higher in patients with pSS than in controls, while circulating levels of resistin were similar in both groups. Resistin was expressed in the epithelial cells of striated ducts and in the lymphocytic foci. Resistin levels in saliva were related to the intensity of inflammation in the minor salivary glands of pSS patients. No changes of the levels of resistin in blood or saliva were observed during DHEA treatment. Exposure of naive leukocytes to DHEA in vitro induced significant expression of resistin compared to nonstimulated peripheral blood mononuclear cells (p=0.031).

CONCLUSION

We showed that levels of resistin are upregulated locally in the salivary glands of patients with pSS; and that the levels of resistin correspond to the intensity of lymphocytic inflammation in patients with pSS. We suggest that resistin is expressed in the salivary glands of patients with pSS and may be a driving factor of local inflammation.

Mucoepidermoid carcinoma with spindle cell change: a low-grade lesion potentially mistaken for sarcomatoid dedifferentiation

An unusual case of mucoepidermoid carcinoma (MEC) of intraoral minor salivary gland origin with spindled morphology was presented. A fascicular stream of bland spindle cells from typical MEC areas amounted to more than 70% of the tumor. Spindle population had features consistent with immunohistochemical and ultrastructural profiles of intermediate cells and lacked overexpression of p53 and cyclin D1. There was no difference in the Ki-67 index between two distinct components. Awareness of extensive spindle cell change replacing a significant portion of low-grade MEC is crucial to avoid an erroneous interpretation of dedifferentiated sarcomatoid transformation.

Basement membrane-like substance in cytologic diagnosis in clear cell adenocarcinoma of the minor salivary gland of the palate. A case report

BACKGROUND

Clear cell adenocarcinoma (CCA) of the minor salivary gland accounts for < 1% of all tumors of the salivary gland.

CASE

A 32-year-old woman with a history of papillary carcinoma of the thyroid 1 year earlier complained of pain on the left side of the neck. After a detailed examination, the patient underwent the resection of a tumor located at the palate. Imprint cytology of the tumor revealed cohesive tumor cells of uniform size containing an abundant clear cytoplasm and round nuclei with extra but fine granular chromatin and conspicuous nucleoli. A basement membrane-like substance (BMS) was stained in light green with Papanicolaou staining and was positive for laminin with immunohistochemical staining. Histopathologic analysis confirmed the trabecular or nest-like arrangement of the cells with the clear cytoplasm and BMS substance surrounded by tumor cells, which were positive for laminin and AE1 immunohistochemically.

CONCLUSION

Although CCA of the palate is extremely rare, an accurate cytologic diagnosis can be made if the characteristic findings of CCA, including BMS, are imaged.

Low salivary dehydroepiandrosterone and androgen-regulated cysteine-rich secretory protein 3 levels in Sjögren's syndrome

OBJECTIVE

Sjögren's syndrome (SS), an autoimmune disease of exocrine glands, typically starts at the time of adrenopause. We undertook this study to test the hypothesis that SS is characterized by an insufficient androgen effect at the target tissue level.

METHODS

We searched for androgen response elements (AREs) in the cysteine-rich secretory protein 3 (crisp-3) gene. Dehydroepiandrosterone (DHEA) responsiveness was experimentally studied using quantitative reverse transcriptase-polymerase chain reaction and immunofluorescence staining of human submandibular gland-derived acinar cells and labial salivary gland explants with or without DHEA. Finally, glandular and salivary CRISP-3 in healthy controls and SS patients was analyzed using immunohistochemistry, in situ hybridization, and enzyme-linked immunosorbent assay. Serum DHEA sulfate (DHEAS) and salivary DHEA levels were measured using a radioimmunometric method.

RESULTS

Literature analysis and a search for AREs in gene banks suggested androgen dependency of human CRISP-3, and this was verified by studies of human submandibular gland acinar cells cultured with or without DHEA, in which DHEA increased CRISP-3 messenger RNA (mRNA) levels (P = 0.018). This finding was confirmed by the results of DHEA stimulation of labial salivary gland explants. Glandular CRISP-3 mRNA and protein labeling was weak and diffuse, coupled with low secretion in saliva (mean +/- SEM 21.1 +/- 2.7 mug CRISP-3/15 minutes in SS patients versus 97.6 +/- 12.0 mug CRISP-3/15 minutes in healthy controls; P < 0.0001). Compared with healthy controls, SS patients had low serum levels of DHEAS (P = 0.008) and also low salivary levels of DHEA (mean +/- SEM 224 +/- 33 pmoles versus 419 +/- 98 pmoles; P = 0.005).

CONCLUSION

CRISP-3 pathology was seen in acini remote from lymphocyte foci and is apparently not secondary to local inflammation, but may represent some systemic effect in SS. Indeed, androgen deprivation in the salivary glands of SS patients is evidenced both by low salivary levels of DHEA and by low levels of DHEA-regulated CRISP-3. This may explain some of the characteristic features of SS.

EGF activates PI3K-Akt and NF-kappaB via distinct pathways in salivary epithelial cells in Sjögren's syndrome

Epidermal growth factor (EGF) exerts tropic effects on salivary epithelial cells. We examined EGF-mediated signaling pathways in the salivary epithelial cells of patients with Sjögren's syndrome (SS). We compared the immunohistochemical expression of EGF receptor (EGF-R), phosphatidylinositol 3-kinase (PI3K), Akt and nuclear factor kappa B (NF-kappaB) in the labial salivary glands of SS patients (n = 6) with those of control subjects (n = 2). EGF-mediated signaling pathways were further studied in vitro (n = 3) using primary salivary epithelial cells; NF-kappaB p65 nuclear translocation and Akt phosphorylation were examined by immunofluorescence and western blotting, respectively. The phosphorylation of EGF-R and Akt, and the nuclear expression of NF-kappaB p65, were increased in situ in the salivary epithelial cells of SS patients compared with those of control subjects. Epidermal growth factor induced rapid EGF-R phosphorylation and NF-kappaB p65 nuclear translocation in primary salivary epithelial cells in vitro. However, EGF also induced late Akt phosphorylation (after 12 h). Chemical inhibition of PI3K-Akt by LY294002/wortmannin did not affect EGF-mediated NF-kappaB p65 nuclear translocation; and NF-kappaB inhibition by Bay 11-7082 did not suppress Akt phosphorylation. Our data suggest that EGF stimulates both the PI3K-Akt pathway and NF-kappaB via distinct mechanisms, promoting tropic effects in SS salivary epithelial cells.

Intraductal carcinoma is the precursor of carcinoma ex pleomorphic adenoma and is often associated with dysfunctional p53

AIMS

Although intraductal carcinoma has been demonstrated in intracapsular carcinoma ex pleomorphic adenoma (CEPA), the morphological and genetic stages of transformation of pleomorphic adenoma (PA) to CEPA are not fully understood. The aim of this study was to investigate the morphology of intracapsular CEPA.

METHODS AND RESULTS

The largest series of intracapsular CEPA studied was subject to immunohistochemical double-staining to detect p53 protein and cellular proliferation in different types of cell combined with mutational analysis of the p53 gene in laser-microdissected material. Intraductal carcinoma with high-grade cellular atypia and frequent accumulation of p53 protein was found in 15/19 cases. Purely intraductal carcinoma was found in eight cases. Mutation of p53 was found in 7/19 cases, of which it was found in intraductal carcinoma in 5/15 cases.

CONCLUSIONS

The frequent demonstration of intraductal carcinoma indicates that this preinvasive lesion is likely to be a constant feature in the malignant transformation of PA to CEPA. It appears to be a feature of CEPA developing from both primary and recurrent PA. The combined immunohistochemical and genetic data show that 14/19 cases of CEPA and 11/15 cases with intraductal carcinoma showed genetic or morphological evidence of dysfunctional p53, indicating that this is an early event in malignant transformation.

Differential expression of Ro/SSA 60 kDa and La/SSB, but not Ro/SSA 52 kDa, mRNA and protein in minor salivary glands from patients with primary Sjögren's syndrome

OBJECTIVE

To analyze the protein and messenger RNA (mRNA) expression of La/SSB, Ro/SSA 60, and Ro/SSA 52 antigens in minor salivary glands (MSG) from patients with primary Sjögren's syndrome (pSS).

METHODS

La/SSB, Ro/SSA 60, and Ro/SSA 52 protein expression was studied by immunohistochemistry in MSG from 26 patients with pSS and 16 controls. mRNA expression was determined by real-time polymerase chain reaction in MSG of 10 patients with pSS and 7 controls.

RESULTS

La/SSB and Ro/SSA 60, but not Ro/SSA 52, mRNA expression was higher in samples from patients with pSS compared to controls (p < 0.05). La/SSB protein had higher expression in the cytoplasm of ductal cells than in the cytoplasm of mucous acinar cells in patients with pSS (p = 0.013) but not in controls. Ro/SSA 60 had higher expression in the cytoplasm of ductal cells than in the cytoplasm of serous acinar cells in patients with pSS (p = 0.006) but not in controls. The Ro/SSA 52 expression pattern was similar in patients and controls. There was no association between circulating autoantibodies to Ro/SSA or La/SSB and the aberrant expression of the cognate autoantigens.

CONCLUSION

The increased Ro/SSA 60 and La/SSB mRNA expression in MSG of patients with pSS as well as the differential Ro/SSA 60 and La/SSB protein expression in ductal cells of MSG in patients with pSS suggest that these these 2 autoantigens, but not Ro/SSA 52, are probably involved in triggering and maintaining the tissue-specific autoimmune response in pSS MSG and may contribute to the antigen-driven immune response and local autoantibody production in pSS.

Acetylcholine synthesis, muscarinic receptor subtypes, neuropeptides and secretion of ferret salivary glands with special reference to the zygomatic gland

Studies on salivary secretion are usually focused on parotid and submandibular glands. However, the film of mucin, that protects the oral structures and is responsible for the feeling of oral comfort, is produced by the submucosal glands. The submucosal zygomatic and molar glands are particularly large in carnivores such as the ferret. Comparisons between the mucous sublingual, zygomatic and molar glands, serous parotid and sero-mucous submandibular glands showed the acetylcholine synthesis, in terms of concentration, to be three to four times higher in the mucous glands than in the parotid and submandibular glands. Bromoacetylcholine inhibited 95-99% of the synthesis of acetylcholine in the incubates of the five types of glands, showing the acetylcholine synthesis to depend on the activity of choline acetyltransferase. The high acetylcholine synthesis in the zygomatic gland was of nervous origin, since cutting the buccal nerve, aiming at parasympathetic denervation, and allowing time for nerve degeneration, reduced the acetylcholine synthesising capacity of the gland by 95%. A similar reduction (96%) in the parotid gland followed upon the avulsion of the parasympathetic auriculo-temporal nerve. Zygomatic saliva was very viscous. The salivary flow rate in response to electrical stimulation (20 Hz) of the buccal nerve (zygomatic gland), expressed per gland weight, was one-third of that to stimulation of the auriculo-temporal nerve (parotid gland) or the chorda-lingual nerve (submandibular gland). As previously shown for the parotid and submandibular gland, a certain fraction (25%) of the parasympathetic secretory response of the zygomatic gland depended on non-adrenergic, non-cholinergic transmission mechanisms, probably involving substance P and vasoactive intestinal peptide and possibly calcitonin gene-related peptide. Particularly, high concentrations of vasoactive intestinal peptide were found in the sublingual and molar glands, and of substance P in the submandibular, zygomatic and molar glands; notably, the concentration of calcitonin gene-related peptide of the sublingual gland was not detectable. All five muscarinic receptor subtypes were detected in the five glands. The receptor protein profile, as judged by immunoblotting and semi-quantitative estimations, was about the same in the glands: high level of M3, low level of M2 and levels roughly in the same range of M1, M4 and M5. Compared to the parotid and submandibular glands, the M5 receptor level was particularly low in the mucin-secreting glands. The present study points out both similarities and dissimilarities between the five types of glands investigated. The zygomatic gland, in particular, appears to be a suitable model for future studies aiming at causing relief of dry mouth by local pharmacological treatment.

Toll-like receptor in salivary glands from patients with Sjögren's syndrome: functional analysis by human salivary gland cell line

OBJECTIVE

We investigated expression of toll-like receptor (TLR) in labial salivary glands of patients with Sjögren's syndrome (SS) and functional TLR expression in the cultured salivary gland cell line.

METHODS

Expression of TLR2, TLR3, TLR4, and myeloid differentiation factor 88 (MyD88) in labial salivary glands was examined by immunohistochemistry. Human salivary gland (HSG) cell-line cells were cultured with TLR ligands [peptidoglycan, poly (I:C) and lipopolysaccharide], and CD54 expression and interleukin 6 (IL-6) production was studied. Phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), p38, and Akt was examined by Western blotting. Activation of nuclear factor-kappaB (NF-kappaB) p65 in HSG cells was studied by NF-kappaB p65 nuclear translocation by microscopic immunofluorescence or chemiluminescent electrophoretic mobility shift assay and detection of NF-kappaB p65 phosphorylation.

RESULTS

TLR2, TLR3, TLR4, and MyD88 were more strongly expressed in the labial salivary glands of SS patients (n =12) than in control subjects (n = 4), and were found in salivary-infiltrating mononuclear cells as well as acinar cells and ductal epithelial cells. In cultured HSG cells, a similar expression pattern was observed, and TLR ligands stimulated CD54 expression and IL-6 production. TLR ligands induced phosphorylation of ERK, JNK, and p38 in HSG cells, but not Akt phosphorylation or activation of NF-kappaB p65.

CONCLUSION

Although the putative ligands remain to be determined, our study indicated the activation of the TLR-mediated immune response in SS, and suggested that the TLR effect is mediated through the mitogen-activated protein kinase pathway.

The feasibility of using infrared thermography to evaluate minor salivary gland function in euhydrated, dehydrated and rehydrated subjects

BACKGROUND

Infrared thermography technique (IRT) is utilized by a growing number of disciplines within medicine and dentistry. However, IRT has not been employed in the evaluation of salivary gland dysfunction. The purpose of this study was to examine the feasibility of using thermographic imaging in the evaluation of minor labial salivary gland function in subjects during euhydration, dehydration, and rehydration states.

METHODS

Ten subjects were studied. Upper labial minor salivary gland secretion was quantified whilst simultaneously visualizing lower minor salivary gland output thermographically during each state.

RESULTS

A significant difference was observed in the minor labial salivary flow among euhydrated, dehydrated and rehydrated, states. Despite the lack of statistical difference in the thermographic findings, IRT images reflected noticeable differences among the three hydration states.

CONCLUSION

The overall results of this study suggest that IRT could potentially provide a valuable non-invasive tool for evaluating the relationship between minor labial salivary gland function and hydration status.

Overexpression of phosphorylated STAT-1alpha in the labial salivary glands of patients with Sjögren's syndrome

OBJECTIVE

To clarify the molecular mechanisms of Sjögren's syndrome (SS), we analyzed the functional role of the STAT-1 gene, one of the interferon-gamma (IFNgamma)-inducible genes, in labial salivary glands (LSGs) from SS patients.

METHODS

The expression of STAT-1 messenger RNA (mRNA) was examined by real-time polymerase chain reaction (PCR) analysis, and the phosphorylation of STAT-1 protein (Tyr(701) and Ser(727) pSTAT-1) was investigated by Western blot and immunohistochemical analyses. The expression of IFNgamma-inducible 10-kd protein (IP-10), IFN regulatory factor 1 (IRF-1), and Fas was also examined by real-time PCR and immunohistochemical analyses.

RESULTS

STAT-1alpha and STAT-1beta mRNA were highly expressed in LSGs from SS patients. The level of STAT-1alpha protein in SS LSGs was higher than that in 3 control LSGs, whereas STAT-1beta protein was not clearly detected by Western blot analysis. Moreover, Tyr(701) and Ser(727) pSTAT-1alpha proteins were specifically detected in SS LSGs. Immunohistochemical analysis showed localization of Tyr(701) pSTAT-1 in infiltrating lymphocytes and the adjacent ductal epithelium from SS patients. Ser(727) pSTAT-1 was localized only in the ductal epithelium of SS LSGs. The STAT-1-inducible genes IP-10 and IRF-1 and the Fas genes were highly expressed in SS LSGs and were colocalized with Ser(727) pSTAT-1-positive, but not Tyr(701) pSTAT-1-positive, cells.

CONCLUSION

We found evidence of the up-regulation of STAT-1alpha mRNA and protein in LSGs from SS patients, as well as the presence of pSTAT-1alpha in ductal epithelium from SS patients. Our findings suggest that STAT-1alpha, especially Ser(727) pSTAT-1, may function as a key molecule in the pathogenesis of SS.

Minor salivary gland secretion rates and immunoglobulin A in adults and the elderly

Previously published data are conflicting about the effect of various factors on secretions from minor salivary glands. The aim of the present study was to investigate the secretion rate from palatal, buccal, and labial glands, and to analyze the immunoglobulin A (IgA) concentrations in relation to age, gender, circulatory disease, diabetes, medication, smoking, and pregnancy. Resting and stimulated whole-saliva secretion rates, as well as IgA concentration in stimulated whole saliva, were also examined. One-hundred and forty two individuals (96 women and 46 men), 18-82 yr of age, participated. The results did not suggest any effect of aging on the secretion capacity of minor salivary glands, but the IgA concentration seemed to increase with age. Women had lower buccal and labial saliva secretion rates, and lower levels of IgA in buccal saliva, than men. For whole saliva, resting, but not stimulated, saliva secretion rates were reduced with age, and the secretion rate of stimulated whole saliva was lower in women than in men. The IgA concentration in buccal saliva showed a positive correlation with IgA in stimulated whole saliva, and the IgA concentration decreased with increased flow rate in both salivas.

TGFbeta3 expression in non-syndromic orofacial clefts

BACKGROUND

Genetic studies have demonstrated that non-syndromic cleft is composed of two separate entities - cleft palate only (CPO) and cleft of lip, alveolus with or without cleft palate (CL+/-P) -, both have a heterogeneous genetic background and environmental factors contribute to the onset of these malformations. Previous studies have shown that TGFbeta3 could be involved in these diseases, but no conclusive results have been reached.

PURPOSE

In order to detect if TGFbeta3 has a role in cleft diseases, a series of non-syndromic cleft patients and controls are analyzed for TGFbeta3 protein expression.

MATERIAL AND METHODS

Forty-three non-syndromic cleft patients and 21 unaffected subjects were involved in this study. Paraffin-embedded specimens were matched with the TGFbeta3 antibody and then scanned with a computerized image analyzer. TGFbeta3 was found to be absent (less than 10%), moderate (from 10% to 30%) and highly expressed (higher than 30%) in epithelium (EP), minor palatal salivary gland (GL) and fibres of elevator palati muscle (MU). Data was statistically analyzed with a Kruskal-Wallis test.

RESULTS

Only GL and EP have a statistically significant lower expression in non-syndromic cleft compared to unaffected subjects. A subsequent comparison between CL+/-P and CPO groups demonstrates a statistically significant difference only for GL, with a lower expression in GL of CPO patients.

CONCLUSIONS

TGFbeta3 is decreasingly expressed in GL of unaffected CL+/-P and CPO patients and thus further strength is given to a pathogenetic role of TGFbeta3 in the onset of clefts.

Increased extracellular levels of the novel proinflammatory cytokine high mobility group box chromosomal protein 1 in minor salivary glands of patients with Sjögren's syndrome

OBJECTIVE

To investigate the expression of the novel proinflammatory cytokine high mobility group box chromosomal protein 1 (HMGB-1) in the salivary glands of patients with Sjögren's syndrome (SS) and patients with sicca symptoms.

METHODS

Biopsy samples from the minor labial salivary glands of patients with SS, patients with sicca symptoms but no diagnosis of SS, and healthy controls were investigated. Expression of HMGB-1, tumor necrosis factor (TNF), and interleukin-1beta (IL-1beta) was analyzed using immunohistochemical staining on consecutive cryosections.

RESULTS

Increased expression of HMGB-1 was observed among the large infiltrates of mononuclear cells found in biopsy samples from patients with SS, and the degree of extracellular HMGB-1 was significantly higher in patients with SS compared with patients with sicca symptoms and with healthy controls (P < 0.05 and P < 0.01, respectively). Cellular expression of TNF was increased in patients with SS and in patients with sicca symptoms. In addition, the level of secreted TNF was significantly higher in patients with SS than in healthy controls (P < 0.05). Intracellular expression of IL-1beta was detected in all groups, while extracellular IL-1beta was observed almost exclusively among the infiltrating mononuclear cells of patients with SS.

CONCLUSION

The increased amount of extracellular HMGB-1 observed in salivary glands of patients with SS indicates that HMGB-1 is involved in the inflammatory process of the disease. This cytokine, along with TNF and IL-1beta, may form a proinflammatory loop that promotes the chronic features of the glandular inflammation in SS.

The homeobox HOXB13 is expressed in human minor salivary gland

BACKGROUND

Homeobox are a family of developmental genes involved in morphogenesis and cellular differentiation. Participation of homeobox within normal and malignant tissue has been recently discussed in the literature.

OBJECTIVE

To analyze the presence of HOXB13 transcript expression in human minor salivary gland.

MATERIAL AND METHODS

Ten-micrometer sections from frozen samples were evaluated employing non-radioactive in situ hybridization technique and HOXB13 mRNA probes.

RESULTS

HOXB13 was found to be expressed in ducts and mucous acini but not in serous acini.

CONCLUSIONS

RESULTS suggest that HOXB13 transcripts are differently expressed in normal mucous and serous acini, and it may possibly reflect a different role in salivary gland carcinogenesis.

Association of Shh and Ptc with keratin localization in the initiation of the formation of circumvallate papilla and von Ebner's gland

The development of gustatory papillae in mammalian embryos requires the coordination of a series of morphological events, such as proliferation, differentiation and innervation. In mice, the circumvallate papilla (CVP) is a specialized structure that develops in a characteristic spatial and temporal pattern in the posterior region of the tongue dorsal surface. The distinct expression patterns of Shh and Ptc, which play important roles in the development of other epithelial appendages, have been localized in the trench wall that gives rise to von Ebner's gland (VEG). To define the cellular mechanisms responsible for morphogenesis and differentiation during early development of CVP and VEG, the localization patterns of keratins (cytokeratins) K7, K8, K18, K19, K14 and connexin-43, which are dependent on Shh expression in other developmental systems, have been examined in detail. The distinct localization of keratins K7, K8, K18, K19, K14 and connexin-43 in the epithelium giving rise to the CVP and VEG suggests that cytodifferentiation is established prior to morphological changes. Interestingly, the localization of proliferating cell nuclear antigen, a marker for cell proliferation, is similar to that of Shh. An understanding of the regulatory roles of cell-cell interactions and signalling molecules in orchestrating a mutual network will bring us nearer to defining the molecular and cellular mechanisms underlying morphogenesis in mammalian taste bud development.

Myoepithelioma of a minor salivary gland of the cheek: case report

Myoepithelioma is a rare neoplasm of the salivary glands, generally occurring in the parotid gland and less often in the minor accessory salivary gland of the oral cavity. The histological appearance includes solid, myxoid and reticular growth patterns. Vimentin and S-100 protein are very sensitive but non-specific immunohistochemical markers of neoplastic myoepithelium. Conservative surgery is the treatment of choice. A case of myoepithelioma of the minor salivary gland of the cheek with low grade malignancy is described, focusing on clinical behaviour, histopathological and immunohistochemical features and differential diagnosis.

Melanin bearing myoepithelial cells in a pigmented salivary gland carcinoma: a new avatar of myoepithelial cell? A case report

Melanocytes can be found in the stroma of salivary glands and their tumors. However, the presence of melanin pigment in the tumor cells of salivary gland origin is exceedingly rare. A 42-year-old man presented with a nasal tumor that was black in color. The histology was that of a minor salivary gland carcinoma with foci resembling an adenoid cystic carcinoma. The myoepithelial cells of this tumor contained melanin pigment. The possible histogenesis of this lesion and an explanation for the occurrence of melanin pigment in a salivary gland tumor are discussed.

Involvement of specific laminins and nidogens in the active remodeling of the basal lamina of labial salivary glands from patients with Sjögren's syndrome

OBJECTIVE

To investigate remodeling of the basal lamina of labial salivary glands (LSGs) from patients with Sjögren's syndrome (SS) by analyzing the expression of specific components that participate in its assembly and attachment to acinar and ductal cells.

METHODS

Two groups of SS patients with similar levels of remnant glandular tissue but with low and high levels of interacinar fibrosis, respectively, were studied. The expression of laminin alpha1, alpha4, and gamma2 chains and nidogens was examined at the messenger RNA (mRNA) and protein levels. Nidogens 1 and 2 were also studied in situ by immunohistochemistry.

RESULTS

Increases in the amount of mRNA and protein for both the processed and unprocessed laminin gamma2-chain were more pronounced in patients with low interacinar fibrosis. Increases in the protein levels of laminin alpha1 and alpha4 chains were observed in patients with low interacinar fibrosis, but not in those with high interacinar fibrosis. Nidogen mRNA and protein levels were similar in SS patients and controls. Interestingly, high levels of nidogen degradation were observed in patients with low interacinar fibrosis. Nidogens were readily detected by immunofluorescence in the basal lamina of the capillaries and stroma in SS patients, but were less apparent in the basal lamina of the acini and ducts.

CONCLUSION

These results suggest that the basal lamina of LSGs from patients with SS is undergoing active remodeling, such that alterations are less evident in patients who have advanced morphologic signs of the disease (high interacinar fibrosis). Nidogen proteolysis might account for the disorganization of the basal lamina that is typically observed in LSGs from SS patients, assuming that cleavage impairs their ability to crosslink type IV collagen and laminin networks.

Pleomorphic Adenoma With Extensive Lipometaplasia

We report a series of three cases of pleomorphic adenoma with extensive lipometaplasia, a recently described subtype of pleomorphic adenoma of salivary gland origin. Two patients were female and one male, ranging in age from 30 to 45 years. Two occurred in the minor salivary glands of the lip and palate, respectively, and one in the parotid. Typical histologic findings are presented. In addition, one case consists of a proliferation of spindle cells with an interesting combination of mature adipose tissue, hyaline cartilage, and bone in the absence of ductal structures. The differential diagnosis, as it pertains to other fat-containing tumors (such as lipoadenoma, spindle cell lipoma, interstitial lipomatosis, and benign mesenchymoma), is discussed. It is likely that the ability of myoepithelial cells to undergo various metaplasias is the cause of the unusual histologic appearances of this tumor.

Oral clearance of an acidic drink in patients with erosive tooth wear compared with that in control subjects

PURPOSE

The aim of this study was to compare the clearance of an acidic drink in patients with tooth wear caused by regurgitation erosion to that in patients without tooth wear.

MATERIALS AND METHODS

Oral clearance was measured using antimony electrodes at 4 soft tissue sites around the mouth in the patients with erosion caused by regurgitation and compared to a matched control group. The data were analyzed for pH at the resting state, the time below 5.5, and the lowest recorded pH. In addition, the resting hydration levels and viscosity of fluid from the minor salivary glands, the pH of resting saliva, and the flow rate and buffering capacity of stimulated saliva were compared between the 2 groups of patients.

RESULTS

The pH recorded at the tip of the tongue reached a lower level in the controls than in those in the erosive tooth wear group (P < .05) and the time that the pH remained below 5.5 was longer in the controls than those with tooth wear (P < .05). The flow rate from the minor salivary glands (P < .05) and the viscosity of resting saliva appeared to differ between the two groups (P < .001).

CONCLUSION

Oral clearance at the tip of the tongue, measured as a function of the lowest pH reached and the time below 5.5, was quicker in those with erosive tooth wear than the controls. It is suggested that this may be a result of a feedback mechanism from constant exposure of the oral environment to low pH.

Autoimmune hepatitis in primary Sjogren's syndrome: pathological study of the livers and labial salivary glands in 17 patients with primary Sjogren's syndrome

Although primary Sjogren's syndrome (pSS) is an autoimmune exocrinopathy, the involvement of liver has been reported. Because no study focusing on autoimmune hepatitis (AIH) in pSS has been published, the purpose of the present study was to perform a clinical and histological examination of the liver, focusing on AIH, in 17 pSS patients. The patients had liver enzyme abnormalities without hepatitis virus infection. In all cases, biopsied livers were examined, and in 10 cases biopsied labial salivary glands were also examined histologically. Based on the authors' diagnostic criteria for AIH in pSS, the liver diseases consisted of AIH (eight cases, 47%), primary biliary cirrhosis (PBC; six cases, 35%), non-specified chronic hepatitis (two cases, 12%) and acute hepatitis (one case, 6%). Lymphoplasmacytic infiltrate, with predominancy of CD3(+) T cells, was noted in both the liver and salivary glands in the patients with AIH. The patients with AIH with severe interface hepatitis had a good response to immunosuppressive therapy. The comparison of liver histology between the PBC with pSS group and the PBC without pSS group showed that the incidence of lymphoid non-suppurative cholangitis was higher in PBC with pSS. In conclusion, the present study offers new information on the relatively common occurrence, diagnostic criteria and treatment effects of AIH in pSS.

Vasculitis and expression of vascular cell adhesion molecule-1, intercellular adhesion molecule-1, and E-selectin in salivary glands of patients with Sjögren's syndrome

OBJECTIVE

We investigated the relationship between clinical symptoms and the grade of histopathological damage and expression of adhesion molecules in salivary glands of patients with Sjögren's syndrome (SS).

METHODS

We studied untreated and recently diagnosed patients with primary (n =20) and secondary SS [10 with SS and rheumatoid arthritis (RA); 10 with SS and systemic lupus erythematosus (SLE)] and 3 healthy controls. Salivary gland biopsies were performed in patients and controls and clinical data were obtained. Salivary gland biopsies were assessed for lymphocyte focus score and expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin. In serum, antinuclear antibodies, rheumatoid factor, anti-Ro and anti-La antibodies, anti-alpha-fodrin IgA and IgG antibodies, and gamma-globulin concentrations were measured.

RESULTS

In salivary gland samples, ICAM-1 was expressed on vascular endothelial cells and lymphocyte foci, while VCAM-1 was expressed on vascular endothelial cells and follicular dendritic reticulin cells. There was a positive correlation between lymphocyte focus score and ICAM-1 expression (p < 0.05). We detected correlation between expression of ICAM-1 and VCAM-1, and the expression of VCAM-1 was significantly related to vasculitis (p < 0.05). The areas of E-selectin expression and the dispersion and severity of staining were not correlated with the focus score or with patients' clinical features (p > 0.05). There was no correlation between the staining and autoantibody positivity and gamma-globulin levels.

CONCLUSION

ICAM-1 may be important for lymphocyte recruitment and glandular damage and VCAM-1 may be important for the development of vasculitis in patients with SS.

Activation of the type I interferon system in primary Sjögren's syndrome: a possible etiopathogenic mechanism

OBJECTIVE

The etiopathogenesis of primary Sjögren's syndrome (SS) is largely unknown. In other autoimmune diseases, type I interferon (IFN) may play a pivotal role by triggering and sustaining the disease process. We therefore aimed to determine whether patients with primary SS had an activated type I IFN system.

METHODS

Salivary gland biopsy specimens and sera from patients with primary SS were investigated for the occurrence of IFNalpha-producing cells and measurable IFNalpha levels, respectively. The ability of primary SS sera together with apoptotic or necrotic cells to induce IFNalpha production in normal peripheral blood mononuclear cells was examined. The IFNalpha inducer was characterized, and IFNalpha-producing cells were identified. Clinical data were correlated with the IFNalpha-inducing capacity of primary SS sera.

RESULTS

Numerous IFNalpha-producing cells were detected in salivary gland biopsy specimens, despite low serum IFNalpha levels. Autoantibodies to RNA-binding proteins, combined with material released by necrotic or late apoptotic cells, were potent inducers of IFNalpha production in plasmacytoid dendritic cells (PDCs). This appeared to be attributable to RNA-containing immune complexes triggering PDCs by means of RNA and interaction with Fcgamma receptor IIa. The IFNalpha-inducing capacity of sera was associated with positive results of a labial salivary gland biopsy (focus score >/=1) and with dermatologic, hematologic, and pulmonary manifestations.

CONCLUSION

Patients with primary SS have an activated type I IFN system. Although virus may initiate the production of IFN, the continued IFNalpha synthesis is caused by RNA-containing immune complexes that activate PDCs to prolong IFNalpha production at the tissue level. This IFNalpha promotes the autoimmune process by a vicious circle-like mechanism, with increased autoantibody production and formation of more endogenous IFNalpha inducers.

A case of mucoepidermoid carcinoma with melanin pigmentation manifested in the palate

This paper describes the first documented case of mucoepidermoid carcinoma (MEC) with melanin pigmentation manifested in the palate. Histopathological sections showed a neoplasm composed of epidermoid, mucous-producing and intermediate cells. Numerous large cells contained dark pigmented materials. Fontana Masson staining revealed dendritic melanocytes and melanin granules. HMB-45, Melan A and S-100 protein were all positive for melanocytes. Histopathological examination was not typical for malignant melanoma; the lesion was diagnosed as a low-grade MEC with melanin pigmentation.

Minor gland saliva flow rate and proteins in subjects with hyposalivation due to Sjögren's syndrome and radiation therapy

In this study, the secretion rate and IgA, albumin and lactoferrin concentrations in minor labial and buccal gland saliva were investigated in individuals with hyposalivation due to primary Sjogren's syndrome (pSS; 10 subjects) or head and neck radiation therapy (RT; 10 subjects) and in their matched controls. Whole saliva was similarly examined. The minor gland saliva flow was measured using the Periotron method. IgA, albumin and lactoferrin concentrations were analysed by ELISA techniques. A general finding was that the flow rate and protein concentrations were lower in labial than in buccal gland saliva. In both hyposalivation groups, the labial minor gland saliva secretion rate was lowered compared to their respective controls. The buccal gland saliva flow rate was significantly reduced in the RT group only. IgA and albumin concentrations were not different from the controls in the labial secretions. The concentration of lactoferrin was increased in the RT group. In buccal saliva, the concentrations of all proteins examined but pSS IgA, were increased compared to the controls. Reduced flow rate and increased protein concentrations were seen for whole saliva where the lactoferrin concentration was higher in RT than in pSS subjects. Thus, our findings suggested that minor gland saliva flow rate and protein concentrations are affected in RT and pSS subjects and to highest extent in the former.