MUC5B levels in submandibular gland saliva of patients treated with radiotherapy for head-and-neck cancer: A pilot study

<p>Abstract</p> <p>Background</p> <p>The salivary mucin MUC5B, present in (sero)mucous secretions including submandibular gland (SMG) saliva, plays an important role in the lubrication of the oral mucosa and is thought to be related to the feeling of dry mouth. We investigated if MUC5B levels in SMG saliva could distinguish between the presence or absence of severe dry mouth complaints 12 months after radiotherapy (RT) for head-and-neck cancer (HNC).</p> <p>Findings</p> <p>Twenty-nine HNC patients with a residual stimulated SMG secretion rate of ≥0.2 ml/10 min at 12 months after RT were analyzed. MUC5B (in U; normalized to 1) and total protein levels (mg/ml) were measured in SMG saliva at baseline and 12 months after RT using ELISA and BCA protein assay, respectively. Overall, median MUC5B levels decreased after RT from 0.12 to 0.03 U (<it>p</it> = 0.47). Patients were dichotomized into none/mild xerostomia (n = 12) and severe xerostomia (n = 17) based on a questionnaire completed at 12 months. SMG and whole saliva flow rates decreased after RT but were comparable in both groups. The median MUC5B level was higher in patients with no or mild xerostomia compared to patients with severe xerostomia (0.14 vs 0.01 U, <it>p</it> = 0.22). Half of the patients with severe xerostomia had no detectable MUC5B at 12 months after RT. No differences in total protein levels were observed.</p> <p>Conclusions</p> <p>Qualitative saliva parameters like MUC5B need further investigation in RT-induced xerostomia. This pilot study showed a trend towards lower MUC5B levels in the SMG saliva of patients with severe xerostomia 12 months after RT for HNC.</p

Human glandular salivas: Their separate collection and analysis

Human saliva is secreted by the three pairs of major salivary glands (parotid, submandibular, and sublingual), and numerous minor ones, e.g. labial, buccal and (glosso)palatine glands. Using individually adapted collection devices, sublingual, submandibular, parotid and palatine secretions of five individuals were collected and analyzed. Electrophoretic analysis revealed that each type of saliva possesses characteristic features, despite interindividual variations. Parotid salivas are characterized by intensely staining amylase and proline-rich protein bands, but contain minute amounts of cystatins, lysozyme and the extra-parotid glycoprotein. Sublingual salivas are characterized by high concentrations of both types of salivary mucins, MG1 and MG2, and contain relatively high levels of lysozyme. Submandibular salivas contain highest concentration of salivary cystatin S. Palatine secretions contain high molecular weight mucins and a relatively high amylase concentration

Treatment of xerostomia with polymer-based saliva substitutes in patients with Sjogren's syndrome

Objective. To determine the efficacy of 3 types of polymer-based saliva substitutes in reducing oral dryness in patients with Sjogren's syndrome (SS). Methods. Subjective efficacy of 3 different saliva substitutes (determined by self-administered questionnaire) was evaluated in a double-blind, placebo-controlled trial in 43 patients with primary and secondary SS. High-viscosity versus low-viscosity xanthan gum-based saliva substitutes were also compared in 33 SS patients, Salivary flow rates (SFR) were determined to examine correlations between the SFR and the subjective efficacy of the saliva substitute. Results. Neither the saliva substitutes nor the placebo was truly effective. Preference for a particular saliva substitute over placebo was equally distributed among the 3 types of substitutes. The SFR of patients who preferred polyacrylic acid-based saliva substitutes was lower than that in patients who preferred the porcine mucin-based substitute (P <0.05). Patients whose oral dryness was reduced by low-viscoelastic substitutes had a low stimulated SFR (<0.20 ml/minute; P <0.05). Conclusion. The optimal properties of a saliva substitute are not the same for all patients with SS, but are dependent on such parameters as the individual SFR. Thus, to determine the best saliva substitute for a particular patient, it is necessary to have the patient try a number of substitutes of different viscoelastic properties