Sialochemistry of whole, parotid, and labial minor gland saliva in patients with oral lichen planus

Patients with oral lichen planus display lower levels of salivary acidic glycoproteins than individuals without oral mucosal disease

OBJECTIVES

Salivary proteins, acidic glycoproteins, and free calcium might take part in oral mucosal defence against inflammation in oral lichen planus (OLP). The study aimed to investigate whether the levels of sulfated and sialylated glycoproteins, total protein, and free calcium in saliva from patients with OLP differ from those of individuals without oral mucosal diseases.

MATERIAL AND METHODS

Patients diagnosed with OLP (n = 25) and two control groups without any oral mucosal disease; age- and gender-matched controls (n = 25, 65.6 ± 2.9 years), and younger controls (n = 25, 41.8 ± 2.5 years) were included. Subjective dry mouth (xerostomia) was assessed by asking a single-item question. Chew-stimulated whole saliva was collected to measure sulfated and sialylated glycoproteins by the Alcian Blue method. The total protein was determined spectrophotometrically, and the free calcium measured using an electrode.

RESULTS

The output of salivary sulfated and sialylated glycoproteins in the OLP group (21.8 ± 2.4 µg/min) was lower than in the age- and gender-matched controls (43.0 ± 2.9 µg/min, p = 0.0002), whereas the total protein and calcium output did not differ between the three groups (p > 0.05). The prevalence of xerostomia was significantly higher in the OLP group compared to both control groups (p = 0.038).

CONCLUSIONS

Patients with OLP showed a high prevalence of xerostomia and lower levels of salivary acidic type glycoproteins compared to the individuals without oral mucosa disease.

CLINICAL RELEVANCE

It is relevant to investigate the role of acidic glycoproteins in the pathogenesis of OLP.

Salivary proteomics in lichen planus: A relationship with pathogenesis?

OBJECTIVES

Oral lichen planus is a chronic, T-cell-mediated, inflammatory disease that affects the oral cavity. The oral lichen planus pathogenesis is still unclear, however, the main evidence is that the mechanisms of activation of different T lymphocyte pathway induce apoptosis with an increase in Th1 and Th17 subtypes cells, triggered by the release of cytokines. This study analysed saliva proteomics to identify protein markers that might be involved in the pathogenesis and development of the disease.

MATERIAL AND METHODS

Proteins differentially expressed by oral lichen planus and healthy controls were screened using mass spectrometry; the proteins found in oral lichen planus were subjected to bioinformatics analysis, including gene ontology and string networks analysis. The multiplex analysis validation allowed the correlation between the proteins identified and the involved cytokines in Th17 response.

RESULTS

One hundred and eight proteins were identified in oral lichen planus, of which 17 proteins showed a high interaction between them and indicated an association with the disease. Expression of these proteins was correlated with the triggering of cytokines, more specifically the Th17 cells.

CONCLUSION

Proteins, such as S100A8, S100A9, haptoglobin, can trigger cytokines and might be associated with a pathological function and antioxidant activities in oral lichen planus.

Oral symptoms and salivary findings in oral lichen planus, oral lichenoid lesions and stomatitis

Background

To examine if patients with oral lichen planus, oral lichenoid lesions and generalised stomatitis and concomitant contact allergy have more frequent and severe xerostomia, lower unstimulated and chewing-stimulated saliva and citric-acid-stimulated parotid saliva flow rates, and higher salivary concentration of total protein and sIgA than cases without contact allergy and healthy controls.

Methods

Forty-nine patients (42 women, aged 61.0 ± 10.3 years) and 29 healthy age- and gender-matched subjects underwent a standardised questionnaire on general and oral health, assessment of xerostomia, clinical examination, sialometry, mucosal biopsy and contact allergy testing.

Results

Nineteen patients had oral lichen planus, 19 patients had oral lichenoid lesions and 11 patients had generalised stomatitis. 38.8% had contact allergy. Xerostomia was significantly more common and severe in patients (46.9%) than in healthy controls, whereas the saliva flow rates did not differ. The patients had higher sIgA levels in unstimulated and chewing-stimulated saliva than the healthy controls. The total protein concentration in saliva was lower in the unstimulated saliva samples whereas it was higher in the chewing stimulated saliva samples from patients when compared to healthy controls. The differences were not significant and they were irrespective of the presence of contact allergy.

Conclusion

Xerostomia is prevalent in patients with oral lichen planus, lichenoid lesions and generalised stomatitis, but not associated with salivary gland hypofunction, numbers of systemic diseases or medications, contact allergy, age, or gender. Salivary sIgA levels were higher in patients than in healthy controls, but did not differ between patient groups. The total salivary protein concentration was lower in unstimulated saliva samples and higher in chewing-stimulated saliva samples in patients than in healthy controls, but did not differ between patient groups. Our findings do not aid in the discrimination between OLP and OLL and these conditions with or without contact allergic reactions.

Xerostomia and Salivary Gland Hypofunction in Patients with Oral Lichen Planus Before and After Treatment with Topical Corticosteroids

BACKGROUND

Oral lichen planus and mouth dryness are common pathoses, yet not entirely understood. These two conditions may be associated, with a few studies investigating the relationship between mouth dryness and oral lichen planus providing conflicting results. None of the studies have explored the specific impact of disease treatment on mouth dryness.

OBJECTIVE

The purpose of this observational before and after comparison study was to examine the effect of treatment of oral lichen planus with topical corticosteroids on mouth dryness.

METHODS

Nineteen subjects with oral lichen planus were evaluated for the severity of xerostomia using a xerostomia inventory and a visual analogue scale. Stimulated and unstimulated whole salivary flow rates, unstimulated salivary pH and buffering capacity were also measured. All subjects were evaluated before and after treatment with topical corticosteroids.

RESULTS

All subjects reported xerostomia before treatment with topical corticosteroids, with 79% reporting a significant improvement (P = 0.03) after treatment. Topical corticosteroid treatment was not associated with statistically significant differences in stimulated or unstimulated salivary flow rates, unstimulated salivary pH or buffering capacity.

CONCLUSION

The results of this study suggest that treatment of oral lichen planus with topical corticosteroids may decrease the severity of dry mouth symptoms.

Salivary changes in oral mucosal diseases

Saliva is a unique biological fluid that can be easily collected and analyzed with low cost and low morbidity. Therefore, there is a growing attention for using salivary biomarkers in the diagnosis and monitoring of disease progress and response to treatment. Salivary changes have been described in relation to oral mucosal diseases. This article discusses the causes and consequences of salivary hypofunction and presents a review of the literature related to changes in salivary parameters in various oral mucosal diseases and in systemic diseases with possible oral mucosal involvement.

Post-allogeneic Hematopoietic Stem Cell Transplantation (HSCT) changes in inorganic salivary components

Recent studies have considered the qualitative and quantitative assessment of salivary flow, as well the biochemical components of saliva, as possible biomarkers that might contribute to the pathogenesis of chronic graft-versus-host disease (cGHVD) in hematopoietic stem cell transplantation (HSCT) patients. The aim of this study was to evaluate prospectively the inorganic salivary status at different periods of allogeneic HSCT. Saliva collection and oral examination were performed prior to the HSCT, ​between days 8 and 10, days 80 and 100, and at the cGVHD onset. Concentrations of calcium (Ca), phosphate (Pi), chloride (Cl), magnesium (Mg), potassium (K), and sodium (Na) were performed using colorimetric reactions and atomic absorption. Fifty-five consecutive patients undergoing first allogeneic HSCT were included in this study. Between days 8 and 10, the salivary flow rate was significantly higher (p = 0.05), Pi concentration was decreased (p = 0.007), and Na and Cl were increased (p = 0.001 and p = 0.001, respectively), compared with the baseline. Salivary flow rate during the same period showed a negative correlation with Pi concentration (p = 0.02) and a positive correlation with Na and Cl concentrations (p = 0.003 and p = 0.001, respectively). The salivary flow rate was decreased between days 80 and 100 (p = 0.02) and Na, Cl, and K concentrations were increased (p = 0.03, p = 0.02, and p = 0.003, respectively). Salivary flow rate showed a negative correlation with Na and Cl (p = 0.01 and p = 0.013, respectively). At cGVHD onset, the salivary flow rate showed no statistical difference compared with the other studied periods. A trend was observed in the higher Na concentration compared with the baseline (p = 0.06) and Pi concentration presented a significant decrease (p = 0.004). Ca and Mg concentrations showed no changes during all evaluation periods. The present study showed changes in inorganic salivary components in post-HSCT periods, mainly during the early period post-HSCT and at the cGVHD onset. We speculate that Na, Cl, and Pi in saliva could be used as a potential biomarker in further studies.

Estimation of serum and salivary immunoglobulin G and immunoglobulin A in oral pre-cancer: A study in oral submucous fibrosis and oral lichen planus

Aim:

Oral submucous fibrosis (OSMF) and oral lichen planus (OLP) are two frequently reported, potentially malignant disorders with multifactorial etiologies and ambiguous pathogenesis. An immunological pathogenesis has been hypothesized as a causative factor for both. The present study aims to evaluate the role of serum and salivary immunoglobulin G (IgG) and immunoglobulin A (IgA) in both these conditions, by their quantitative estimation.

Materials and Methods:

Saliva and serum samples were collected from 30 patients, clinically diagnosed and histopathologically confirmed with OSMF, 30 with OLP and 30 age and sex matched controls. The levels of IgG and IgA were estimated by nephelometry.

Results:

The mean values of serum IgG were marginally higher in both OSMF and OLP groups compared to the controls but this difference was not significant and the mean values of serum immunoglobulin A were marginally decreased in both the study groups compared to the controls but this difference was also not significant. Inconclusively low levels of salivary IgG and IgA were obtained in the three groups.

Conclusion:

The present study suggests an insignificant association of these immunoglobulins in the pathogenesis of both these diseases.

An update on minor salivary gland secretions

In this article, the literature on minor salivary gland secretion rates, composition, and function is reviewed. Measurements of the minor salivary gland secretion rates and composition are complicated, and the secretions display large biological variability. Despite this, some characteristics of these secretions have been found repeatedly in independent investigations. Minor gland saliva varies between different oral sites. Buccal saliva flow is higher than labial saliva flow, which in turn is usually higher than the palatal gland secretion rate. It is generally agreed that minor gland saliva is important for the whole saliva composition, and especially for the secretory immunoglobulin A and mucins. The secretion from these glands seems also important for subjective feelings of dry mouth and general wellbeing. Further research is essential for understanding the role of these secretions for oral, as well as for general, health.

Salivary IgA and IgG subclasses in oral mucosal diseases

OBJECTIVE

It was hypothesized that serum levels of immunoglobulins may play a role in the pathogenesis of oral mucosal diseases, or reflect clinical changes in these conditions, but little is known about the role of salivary immunoglobulins in the pathogenesis of these diseases. The aim of this study was to investigate possible alterations in salivary immunoglobulin A (IgA) and IgG subclasses in patients with oral mucosal inflammatory diseases.

SUBJECTS AND METHODS

Levels of IgG1, IgG2, IgG3 and IgG4 were determined by enzyme-linked immunosorbent assay (ELISA), and IgA1 and IgA2 by radial immunodiffusion in the resting whole saliva of 31 patients with acute recurrent aphthous ulceration (RAU) (and followed in remission), 11 patients with chronic hyperplastic candidal infection (CHC), 12 patients with Sjogren's syndrome (SS), six patients with oral lichen planus (OLP), and 18 healthy volunteers using the normal saliva as a comparison point for all.

RESULTS

IgG and IgA subclasses were increased in OLP. In CHC all IgG subclasses were increased while IgA1 was decreased, IgG1, IgG3 and IgG4 levels were increased in SS, while all IgG subclasses as well as IgA2 were increased in acute RAU in comparison with healthy controls. No differences in any immunoglobulin subclasses between major and minor acute RAU were found. In remission, IgG1 and IgG4 returned to normal values while IgG2, IgG3, and IgA2 remained increased in patients with RAU.

CONCLUSION

Salivary immunoglobulin subclasses vary in different oral mucosal conditions and may play a role in oral mucosal inflammatory diseases and/or reflect clinical changes in these conditions.

Langerhans cells and T cells in oral graft versus host disease and oral lichen planus

Chronic graft versus host disease (cGVHD) of the oral mucosa, following allogeneic stem cell transplantation, and oral lichen planus (OLP) are both mucosal diseases where the immune system is involved in the pathogenesis. Although the aetiology of the two conditions is different, they present with a similar clinical appearance. This study compares the two diseases regarding the distribution of cells, which are expressing cell surface markers of interest for inflammatory responses. Monoclonal antibodies (MoAbs) were used in standard immunohistochemical procedures. CD1a+, CD80+ and CD86+ cells in the epithelium of OLP- and cGVHD lesions had the dendritic morphology of Langerhans cells (LC). Higher frequencies of CD1a+ LC as well as CD25+ cells were observed in the OLP epithelium than in the cGVHD epithelium. The OLP lesions showed higher frequencies of subepithelial cells expressing CD1a, CD86, CD4, CD8 and CD25 than the cGVHD lesions. Notably there was a significantly higher frequency of CD25+ cells in the epithelium and the connective tissue of OLP than in cGVHD. These cells might represent regulatory T cells. In conclusion, cGVHD and OLP show marked differences at the cellular level despite similar clinical appearance. Hence, the findings indicate differences in the regulation of the inflammatory response between the two conditions.

Xerostomia and hyposalivation

Dry mouth must not be considered a trivial problem in the population, since it constitutes a phenomenon with many aspects relative to oral function as well as quality of life. Up until today, no global consensus has been reached with regard to the terminology of dry mouth, creating a substantial problem for research, education, diagnosis, and therapy. In this report, salivary gland hypofunction has been selected as the overarching term for subjective symptoms and objective signs of dry mouth. Its different aspects--xerostomia, hyposalivation, and altered saliva composition--are reviewed with respect to prevalence, diagnosis, and etiology. It is concluded that these aspects of salivary gland hypofunction are separate entities, which in many respects are interrelated, constituting not merely a dental but also a medical and social concern.

The flow rate and composition of human labial gland saliva

Since the flow rate of saliva from human labial salivary glands has usually been measured as the secretion from an area of labial mucosa as 0.05-4.8 microl/cm2/min. The only data for single glands gives a comparable figure of 0.1 microl/min/gland. There is no consensus on the effects of gustatory stimulation, gender or ageing, although most reports suggest that flow rate is not related to gender and ageing up to age 60. The main differences in composition between labial gland saliva and that from the major glands are the higher and variable sodium concentration, the very low phosphate and hydrogen carbonate concentrations, and the higher protein concentration despite low concentrations of amylase. The concentrations of IgA and blood group substances are notably higher in labial gland saliva. In Sjogren's syndrome and cystic fibrosis flow rates are decreased. Low rates of flow have been associated with a higher incidence of dental caries.

A method for measuring the flow of saliva from the minor salivary glands

This investigation evaluated a procedure to measure the quantity of secretion by the minor salivary glands from various locations in the mouth before and after citric acid stimulation. Fourteen healthy non-medicated adults were assessed on each of two morning visits at the same specific areas of the mucosa (labial, buccal, and palatal). During each assessment, an absorbent paper strip was placed on each designated location for 30 s, removed, and its moisture content determined with a calibrated Periotron. Calibration procedures indicated that readings were linearly associated with known saliva volumes and were negligibly influenced by differences in salt concentration and viscosity. At each visit, the buccal flow was significantly greater than those from the lip and palate. The flow from glands in each area was unaffected by a single application of the gustatory stimulant. The mean flow rates at each specified site were similar during the two visits.