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 levels of interleukin-8 and growth factors are modulated in patients with geographic tongue.

OBJECTIVES: The aim of the study was to determine the levels of salivary epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) as well as interleukin-8 (IL-8) in patients with geographic tongue (GT), as compared to control subjects. METHODOLOGY: An enzyme-linked immunosorbent assay was used to measure the levels of IL-8, EGF and VEGF in whole saliva samples collected from 34 patients with GT and 38 control subjects. The patients and controls were grouped and matched according to age, gender and the presence of systemic diseases, which are factors that may influence the levels of salivary biomarkers. RESULTS: All patients with GT displayed significantly higher levels of IL-8 than the controls (P < 0.001). The young female patients also showed reduced levels of EGF (P < 0.05) and VEGF (P < 0.05), as compared to the young male patients where no such differences were observed. Interestingly, high levels of IL-8 (P < 0.001) and VEGF (P < 0.05) were detected in the patients with GT who also suffered from hypertension. CONCLUSION: We consider IL-8 an inflammatory mediator, which contributes to the acute inflammatory response found in GT. EGF and VEGF also seem to be involved in the pathophysiology of GT.

Melatonin-induced protein synthesis in the rat parotid gland.

Melatonin occurs in large amounts in the intestinal mucosa and is released during a meal. Recent studies of ours reveal that exogenous melatonin evokes the in vivo secretion of protein and amylase from the rat parotid gland. The aim of the present study was to investigate the effect of melatonin on the protein synthesis of the parotid gland of pentobarbitone-anaesthetised rats as estimated by the rate of incorporation of [³H]leucine into trichloroacetic acid-insoluble material of the gland. Compared with the parotid protein synthesis (set at 100%) of those rats exposed to an intravenous infusion of melatonin (25 mg/kg during 1 hour), under muscarinic and α- and ß-adrenoceptor blockade, the synthesis in the corresponding glands of saline-treated control rats was less (by 25%). The synthesis was also less when the melatonin administration was combined with the melatonin 2-preferring receptor antagonist luzindole (24%), the non-selective nitric oxide synthase inhibitor L-NAME (18%) and the neuronal nitric oxide synthase inhibitor N-PLA (21%). Almost all the melatonin receptor-mediated effect was due to nitric oxide generation via the activity of neuronal type nitric oxide synthase. The present findings lend further weight to the idea that salivary glandular activity associated with food intake is hormonally influenced and they also suggest clinical implications for melatonin in the treatment of xerostomia. Since melatonin is known to exert anti-inflammatory actions in the oral cavity, the stimulatory effect of melatonin may include the synthesis of proteins of importance for the oral defence.

Anti-inflammatory action of cholecystokinin and melatonin in the rat parotid gland.

OBJECTIVE: To define the influence of cholecystokinin and melatonin on the inflammatory response of the lipopolysaccharide-exposed rat parotid gland. MATERIALS AND METHODS: Bacterial lipopolysaccharide was infused retrogradely into the parotid duct. The degree of inflammation three hours postadministration was estimated from the activity of myeloperoxidase, reflecting glandular neutrophil infiltration. RESULTS: The myeloperoxidase activity of the lipopolysaccharide-exposed gland was 10-fold greater than that of the contralateral gland. Combined with sulphated cholecystokinin-8 (10 or 25 µg kg(-1) , given twice intraperitoneally) or melatonin (10 or 25 mg kg(-1) x 2) the lipopolysaccharide-induced response was elevated 4.6- and 3.5-folds at the most. The cholecystokinin-A receptor antagonist lorglumide reduced the inhibitory effect of cholecystokinin-8, while the melatonin 2-preferring receptor antagonist luzindole had no effect on the melatonin-induced inhibition. Unselective nitric oxide-synthase inhibition abolished the increase in myeloperoxidase activity, whereas inhibition of inducible or neuronal nitric oxide-synthase (of non-nervous origin) halved the inflammatory response. CONCLUSION: Some hormones may contribute to anti-inflammatory action in salivary glands in physiological conditions. They are potential pharmacological tools for treating gland inflammation. The inflammation, as judged from the myeloperoxidase activity, was entirely dependent on nitric oxide-synthase activity, indicating that the hormones directly or indirectly reduced the generation of nitric oxide.