Stimulated saliva composition in patients with cancer of the head and neck region

Ulrica Almhöjd,Niclas Karlsson,Hulya Cevik-Aras,Annica Almståhl,Jin Chuncheng

doi:10.1186/s12903-021-01872-x

Abstract

BackgroundTo analyse over time changes in stimulated whole saliva regarding total protein, Immunoglobulin A (IgA), and mucin type O-glycans (mostly MUC5B and MUC7) in head and neck cancer patients.Methods29 dentate patients (20 men and 9 women, 59 ± 8 years) treated with curative radiation therapy and chemotherapy for cancer of the head and neck region were included. The stimulated whole salivary secretion rate was determined and saliva collected at four time-points: at pretreatment, and at 6 months, 1 and 2 years post treatment. The total protein concentration was determined spectrophotometrically by using Bicinchoninic Acid assay and Immunoglobulin A (IgA) by using ELISA technique. Glycosylation pattern of salivary mucins was determined in samples collected pre- and post treatment by using LC/MS electrospray and mucin content quantified using SDS-AgPAGE gels and PAS staining.ResultsCompared with pretreatment, the total protein concentration was increased already at 6 months post treatment (p < 0.01), and continued to increase up to 2 years post treatment (p < 0.001). During that period no significant changes in IgA concentration was detected. At pretreatment, the output/min of both total protein and IgA was significantly higher than at all time-points post treatment. Saliva from the cancer patients showed a low abundance/no detectable MUC7, while the MUC5B level remained, compared to saliva from a healthy control. The glycomic analysis showed that the percentage of core 2 O-glycans was increased as core 1, 3 and 4 O-glycans were decreased. The level of sialylation was higher at 6 months post treatment, while sulfation was lower.ConclusionA decreased output per minute of proteins at decreased salivary secretion rate, as well as reduced sulfation of MUC5B at 6 months post treatment tended to correlate with the patients’ experience of sticky saliva and oral dryness. At 2 years post treatment, the decreased amount of IgA combined with a lowered salivary secretion rate indicate a reduced oral defense with increased risk of oral infections.

Highlights

To analyse over time changes in stimulated whole saliva regarding total protein, Immunoglobulin A (IgA), and mucin type O-glycans in head and neck cancer patients
The output per min of both total protein and IgA in stimulated whole saliva were decreased post treatment compared with pretreatment
The present study showed a higher total protein concentration in stimulated whole saliva (1.6 mg/mL; flow rate 2.0 mL/min) for the cancer patients at pretreatment when compared to a previous study including healthy controls (0.9 ± 0.2 mg/mL; flow rate 2.3 mL/min) [18]

Summary

Introduction

To analyse over time changes in stimulated whole saliva regarding total protein, Immunoglobulin A (IgA), and mucin type O-glycans (mostly MUC5B and MUC7) in head and neck cancer patients. Saliva has many important functions for oral health [5]. It helps bolus formation of food, aids at mastication and swallowing, and is important for oral clearance (especially stimulated saliva). Saliva covers soft and hard surfaces of the oral cavity and is important for lubrication (especially unstimulated saliva) as well as the protection against pathogenic microbes [6]. An early complication of treatment of cancer of the head and neck region is a reduced salivary secretion rate starting about 2 weeks into radiotherapy [7]. The unstimulated salivary secretion rate is mostly very low or even unmeasurable in patients who have undergone treatment of head and neck cancer [9]

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