Evaluation of the masticatory biomechanical function in Down syndrome and its Influence on sleep disorders, body adiposity and salivary parameters.

OBJECTIVE: To evaluate the phenotypic features of the masticatory biomechanics in atypical subjects with Down syndrome (DS). Its influence was analysed on sleep disorders, body adiposity and its risks, and some physicochemical properties of saliva. METHODS: Seventy subjects were enrolled to assess masticatory biomechanical function and divided into two groups: DS and control groups. Electrical activities of the masseter and temporal muscles (at rest and in maximum voluntary clench-MVC), maximum bite force-MBF and maximum mouth opening-MMO were investigated. Among the atypical subjects, just 24 participants underwent the anthropometry, the polysomnography II and the saliva testing (salivary flow rate-SFR, buffer capacity-BC and salivary cortisol levels, morning/SC-AM and night/SC-PM). RESULTS: MVC and MBF values showed high statistical significance in the control group (P < .001) than in the DS group of 35. MMO values were slightly increased in the DS group in relation to the control group. Overweight and obesity were found in both genders. Atypical women showed higher risk to develop cardiovascular-metabolic diseases than in atypical men. OSA severe was 20% for atypical women and 42.8% for atypical men, whereas snoring index was present in all genders. SFR was reduced in 100% of atypical subjects (hyposalivation in 10% women and 28.5% men). Furthermore, 100% BC, 66.6% SC-AM and 91.6% SC-PM showed normal patterns. CONCLUSION: Masseter and temporal muscle hypotonia was found in all atypical subjects with DS. This muscle dysfunction strongly was related to overweight/obesity, risks for development of cardiovascular/metabolic diseases, OSA severity, successive snoring episodes and salivary flow reduction in DS.

Análise dos níveis de cortisol salivar em jovens e adultos com síndrome de Down e apneia obstrutiva do sono: estudo transversal / Analysis of salivary cortisol levels in young people and adults with Down syndrome and obstructive sleep apnea: cross-sectional study

A apneia obstrutiva do sono (AOS) é um transtorno potencialmente grave e altamente prevalente na síndrome de Down (SD), sendo de grande relevância o conhecimento de causa e efeito entre essas duas condições. A AOS desencadeia eventos estressantes como esforços respiratórios e alteração da pressão arterial. O eixo hipotálamopituitária-adrenal (HPA) constitui-se em um conjunto de interações responsivas ativadas a partir de estímulos estressores, tendo como um dos produtos finais a secreção do cortisol, sendo esse o principal hormônio glicocorticoide secretado pelas glândulas adrenais, com funções de controlar as reações ao estresse. Estudos buscam identificar uma relação entre a AOS e as variáveis circadianas do cortisol, afim de encontrar biomarcadores que possam facilitar a detecção e avaliação de risco para AOS. Este estudo transversal mapeou os padrões matinais e noturnos de cortisol salivar em um grupo de jovens e adultos com SD, e avaliou as associações entre os níveis de cortisol e a presença de AOS (leve, moderada e grave). Os níveis de cortisol foram obtidos por meio de amostras salivares, por ser um biofluido que apresenta um excelente índice da fração livre do cortisol com resultados confiáveis, além da vantagem de ser umexame não invasivo e eficiente. Em adição, parâmetros salivares de cada participante foram avaliados por medidas sialométricas e sialoquímicas, obtendo-se valores da capacidade tampão, taxa de fluxo salivar e viscosidade. Foram selecionados 23 jovens e adultos com SD e AOS, de ambos os gêneros, com idades entre 18 e 26 anos, e submetidos a coletas de amostras de saliva em diferentes horários respeitando as variáveis fisiológicas do ciclo circadiano, para avaliações sialométricas e sialoquímicas. As coletas de saliva foram realizadas através de uma bomba de sucção adaptada para essa finalidade, e as análises de cortisol salivar por meio de um kit enzima imunoensaio. O resultado mostrou que não houve significância estatística entre AOS e as variáveis exploratórias gênero, cortisol salivar matinal e noturno, fluxo salivar, viscosidade e capacidade tampão. Os graus de AOS (leve, moderada e grave) não tiveram efeito significativo sobre cortisol salivar matinal e noturno. Todos os participantes apresentaram baixas taxas de fluxo salivar, capacidade tampão dentro de padrões de normalidade e, pelo menos metade dos participantes, apresentou baixos níveis de viscosidade salivar. Concluímos que a maioria dos jovens e adultos com SD e AOS, apresentou condição de normocortisolismo em ambos os períodos matinal e noturno, sugerindo ausência de risco de estresse psicológico e/ou físico. Apesar de não haver significância estatística, foram detectados quadros de hipercortisolismo e hipocortisolismo em períodos distintos e com diferentes graus de AOS.Os níveis de cortisol salivar apresentaram-se heterogêneos nos pacientes com SD independente dos graus de AOS. Por fim, foi observada redução na secreção e viscosidade salivar, com impacto negativo para mastigação, deglutição, fonação e percepção do paladar, sugerindo que seja realizada gestão salivar em pessoas com SD(AU)

Obstructive sleep apnea (OSA) is a potentially serious and highly prevalent disorder in Down syndrome (DS), with great relevance the knowledge of cause and effect between these two conditions. OSA triggers stressful events such as breathing efforts and changes in blood pressure. The hypothalamic-pituitary-adrenal (HPA) axis is a set of responsive interactions activated from stressful stimuli, with cortisol secretion as one of the end products, which is the main glucocorticoid hormone secreted by the adrenal glands, with functions to control the reactions to stress. Studies seek to identify a relationship between OSA and circadian cortisol variables, in order to find biomarkers that can facilitate the detection and risk assessment for OSA. This cross-sectional study mapped the morning and night patterns of salivary cortisol in a group of young people and adults with DS, and assessed the associations between cortisol levels and the presence of OSA (mild, moderate and severe). Cortisol levels were obtained by means of salivary samples, as it is a biofluid that has an excellent index of the free fraction of cortisol with reliable results, as well to the advantage of being a non-invasive and efficient test. In addition, salivary parameters of each participant were evaluated by sialometric and sialochemical measurements, obtaining values of buffer capacity, salivary flow rate and viscosity. Method: 23 young people and adults with DS and OSA, of both genders, aged between 18 and 26 years old, were selected and submitted to the collection of saliva samples at different times respecting the physiological variables of the circadian cycle, for sialometric and sialochemical evaluations. Saliva collections were performed using a suction pump adapted for this purpose, and salivary cortisol analysis using an immunoassay enzyme kit. Results: There was no statistical significance in the association between OSA and the exploratory variables gender, morning and night salivary cortisol, salivary flow, viscosity and buffer capacity. The degrees of OSA (mild, moderate and severe) had no significant effect on morning and evening salivary cortisol. All participants had low salivary flow rates, buffer capacity within normal standards, and at least half of the participants had low levels of salivary viscosity. Conclusion: The majority of young people and adults with DS and OSA showed a condition of normocortisolism in both morning and night periods, suggesting the absence of risk of psychological and / or physical stress. Although there was no statistical significance, hypercortisolism and hypocortisolism were detected in different periods and with different degrees of OSA. Salivary cortisol levels were heterogeneous in DS patients regardless of OSA degrees. Finally, a reduction in salivary secretion and viscosity was observed, with a negative impact on chewing, swallowing, phonation and perception of taste, suggesting that salivary management be performed in people with DS(AU)

Galleria mellonella as an experimental model to study human oral pathogens.

The oral cavity is home to a microbial community of more than 800 species. This important microbiome is formed by commensal and opportunistic bacteria, fungi and viruses. Several distinct habitats within the mouth support heterogeneous microbial communities that constitute an important link between oral and general health. The use of animal models for in vivo studies in microbial pathogenicity is well established in the scientific community. Galleria mellonella as a model host has increased in use significantly in the last few years. This invertebrate model provides studies on a large scale, serving as screens for studies on vertebrate animals, such as mice and rats. In this review, different studies of microbial genera of dental importance (Enterococcus, Candida, Lactobacillus, Porphyromonas and Streptococcus) are discussed, highlighting the use of G. mellonella as a suitable model for studying pathogenesis, efficacy of antimicrobial compounds, and immune responses.