Voltage-gated sodium channels gene expression in Burning Mouth Syndrome: a case-control study.

Burning mouth syndrome (BMS) is a condition characterized by painful symptoms of the oral mucosa, despite the absence of any clinical signs. Its etiology is unknown, and there is still no effective treatment to date. Current evidence has shown neuropathic impairment in BMS patients. Neuropathic pain can be related to the dysfunction of voltage-gated sodium channels, considering that these receptors regulate the induction of action potentials in nociceptive neurons. This study evaluated the gene expression of voltage-gated sodium channels Na v 1.7, Na v 1.8 and Na v 1.9 in these patients. The gene expressions of these channels were assessed by real time RT-PCR analysis of fresh-frozen tongue biopsies in a case-control study composed of 12 patients with BMS, and 5 healthy control patients, proportionally matched by sex and age, and analyzed using the 2^(-Delta Delta CT) method. There was no statistically significant difference between the analyzed groups, despite the increase in Na v 1.7 (fold-change = 3.13, p = 0.52) and decrease in Na v 1.9 (fold-change = 0.45, p = 0.36) gene expression in the BMS group. The Na v 1.8 gene was not expressed in any of the samples analyzed. Although the gene expression in the voltage-gated sodium channels in BMS under study seems to be comparable with that of the normal oral mucosa, the functionality of these channels in BMS has not yet been identified, thus suggesting that further research is needed to better understand these voltage-gated sodium channels.

Evaluation of IL-6 levels and +3954 polymorphism of IL-1ß in burning mouth syndrome: A systematic review and meta-analysis.

This study evaluated IL-6 salivary levels as well as the +3954 polymorphism of IL-1ß in patients with burning mouth syndrome and healthy individuals, through case-control studies. This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We conducted this research in PubMed/MEDLINE, Cochrane Library and Web of Science databases. The risk of bias was measured based in the Newcastle-Ottawa Scale. Researches with a group of patients with burning mouth syndrome and a control group in which the presence of the +3954 polymorphism of IL-1ß and/ or IL-6 salivary levels through non-stimulated saliva were evaluated to detect if this interleukin concentrations are increased in patients and if the polymorphism is a risk factor for this syndrome. We identified seven studies with total of 440 participants, 229 patients with burning mouth syndrome and 211 healthy controls, ages 24-84 years old. The female gender was predominant. Patients in the majority of studies did not present increased levels of IL-6 and the +3954 polymorphism of IL-1ß is not a risk factor for this syndrome. A few studies researched biomarkers in this pathology and more investigations are required not only to identify salivary levels and the polymorphism evaluated, but also other interleukins and polymorphisms in order to clarify the etiopathogenesis of this syndrome as well as for propose new diagnostic methods and treatments.

Comparative Analysis of Psychological, Hormonal, and Genetic Factors Between Burning Mouth Syndrome and Secondary Oral Burning.

OBJECTIVE: The objective of this study was to evaluate the association between psychological, hormonal, and genetic factors with the development of burning mouth syndrome (BMS) and secondary oral burning (SOB) in order to provide a better characterization and classification of these conditions. DESIGN: Cross sectional study. SETTING: Patients with complaints of mouth burning registered at the Oral Diagnostic Service of the Federal University of Rio Grande do Norte between 2000 and 2013. SUBJECTS: The sample consisted of 163 subjects divided into a group of patients with BMS (n = 64) and a group of subjects with SOB (n = 99). METHODS: The following variables were analyzed: passive and stimulated saliva flow, stress levels and phase, depression, anxiety, serum cortisol and dehydroepiandrosterone (DHEA) levels, and the presence of polymorphisms in the interleukin 6 (IL-6) gene. RESULTS: The results showed significant differences in the presence of xerostomia (p = 0.01), hyposalivation at rest (p < 0.001) and symptoms of depression (p = 0.033) between the two groups, which were more prevalent in the BMS group. DHEA levels were lower in the BMS group (p = 0.003) and were sensitive and specific for the diagnosis of this condition. Genetic analysis revealed no significant association between the polymorphisms analyzed and the development of BMS. CONCLUSION: These results suggest a possible role of depression, as well as of reduced DHEA levels, as associated factors for development of BMS.

Interleukin-1beta and serotonin transporter gene polymorphisms in burning mouth syndrome patients.

UNLABELLED: Burning mouth syndrome (BMS) is a chronic pain syndrome that encompasses all forms of burning sensations in the oral cavity when the oral mucosa is clinically normal. Neural, psychologic, and cytokine factors may be implicated in the pathogenesis of BMS. There are no studies of genetic factors associated with psychologic behavior and cytokine pain sensitivity in BMS patients. The purpose of the present study was to investigate a possible association between functional genetic polymorphisms, +3,954 (C/T) interleukin-1beta, and the polymorphic site on promoter region of the serotonin transporter gene (5-HTTLPR) in a sample of Brazilian patients. Thirty patients affected by BMS and 31 healthy volunteers were genotyped for 5-HTTLPR and IL-1beta gene. The chi-squared test was used for statistical analysis. There was no statistical difference in 5-HTTLPR genotypes between the case and control groups (P = .60), however a significant increase was observed in the IL-1beta high production genotype CT in BMS subjects (P = .005). In conclusion, the present study shows association between BMS and IL-1beta high producer genotype. PERSPECTIVE: This article shows evidence that genetic polymorphisms associated with IL-1beta high production genotype are implicated on the pathogenesis of BMS. The modulation of IL1beta production may be an interesting tool in BMS management.