RESUMO
Recent evidence suggests that genetic studies may contribute to a better understanding of individual susceptibility to caries. Matrix metalloproteinases (MMPs) and their tissue inhibitors have been suggested to be involved in the caries process. The purpose of this study was to determine if polymorphisms in MMP2 (rs243865), MMP9 (rs17576), MMP13 (rs2252070), and TIMP2 (rs7501477) were associated with caries. Eligible unrelated children and adolescents were evaluated using a cross-sectional design. Data on oral health habits was obtained through a questionnaire and caries data was collected by clinical examination. Genotyping of the selected polymorphisms was carried out by real-time PCR. Allele and genotype frequencies were compared between individuals with and without caries experience. Of 505 subjects, 212 were caries-free and most subjects (61.2%) had mixed dentition. Allele frequency of MMP2, MMP13 and TIMP2 was different between caries-affected and caries-free individuals, with significant association for MMP13 (p = 0.004). Mutant allele carriers for MMP13 demonstrated a significantly decreased risk for caries (OR = 0.538, 95% CI 0.313-0.926); this result remained significant after adjustment for candidate genes, type of dentition and dietary factors. Allelic and genotype frequencies of the polymorphism in MMP9 were similar in caries-affected and caries-free individuals. Genetic variations in MMP13 may contribute to individual differences in caries susceptibility. Our findings reinforce that susceptibility to caries results from gene-environment interactions.
Assuntos
Suscetibilidade à Cárie Dentária/genética , Cárie Dentária/genética , Metaloproteinase 13 da Matriz/genética , Polimorfismo Genético/genética , Adenina , Adolescente , Alelos , Criança , Pré-Escolar , Estudos de Coortes , Estudos Transversais , Índice CPO , Dentição Mista , Sacarose Alimentar/administração & dosagem , Feminino , Frequência do Gene/genética , Interação Gene-Ambiente , Genótipo , Guanina , Humanos , Masculino , Metaloproteinase 2 da Matriz/genética , Metaloproteinase 9 da Matriz/genética , Mutação/genética , Polimorfismo de Nucleotídeo Único/genética , Inibidores de Proteases , Inibidor Tecidual de Metaloproteinase-2/genética , Adulto JovemRESUMO
BACKGROUND: Photodynamic therapy (PDT) has been described for photoageing treatment, but its mechanism of action is not clarified. Although PDT-induced matrix metalloproteinase (MMP) expression and collagen production have been studied in normal skin and in inflammatory disease, there is no report about the effect of PDT on the extracellular matrix in photodamaged skin. OBJECTIVES: To evaluate skin remodelling induced by methyl aminolaevulinate (MAL)-PDT in photodamaged skin by histological and immunohistochemical studies. METHODS: Fourteen patients were treated with two sessions of MAL-PDT. The light source was a light-emitting diode (635 nm, 37 J cm(-2)). Skin biopsies were performed in all patients before and at 3 and 6 months after treatment. Immunohistochemical studies evaluated collagen types I and III, MMP-1, MMP-3, MMP-7, MMP-9, MMP-12 and tissue inhibitor of metalloproteinases-1. RESULTS: Global improvement in photodamaged skin was observed. A significant increase in expression of MMP-9 in the dermis was detected at 3 months after treatment (P = 0.002). Significant increases in the expression of collagen type I at 3 months (P = 0.002) and at 6 months after treatment (P = 0.001) were also observed. CONCLUSIONS: Skin remodelling induced by MAL-PDT was demonstrated in photodamaged skin. Two sessions of MAL-PDT increases immunohistochemical expression of MMP-9 in the dermis at 3 months after treatment, and also of collagen type I.
