Research progress on the relationship between enamel-related gene polymorphisms and caries susceptibility / 口腔疾病防治

@#Caries is a frequently occurring oral disease that is caused by chronic, progressive destruction of dental hard tissue. The enamel is the superficial layer of the tooth crown; enamel formation-related genes play an important role in the development of enamel, and enamel demineralization is a prerequisite for the occurrence of caries. Therefore, this paper reviewed the relationship between enamel-related gene polymorphisms and caries susceptibility and its possible mechanisms to provide new ideas for the prevention and treatment of caries. The results of a literature review showed that the gene polymorphisms related to enamel formation may increase or decrease susceptibility to caries by influencing the development and structure of enamel. For example, ENAM rs3796703 CT can increase the susceptibility to caries, and AMBN rs34538475 TT can reduce the susceptibility to caries. In the future, the detection and analysis of polymorphisms related to enamel formation that affect the structure or development of enamel may serve as a clinical method to evaluate the susceptibility of caries, which is of great significance for the early prevention and treatment of the disease.

Differential Expression of Amelogenin, Enamelin and Ameloblastin in Rat Tooth Germ Development

Tooth development shows dynamic morphological changes from the stages of cap to hard tissue formation and is strictly regulated during development. In the present study, we compared expression and localization of 3 major enamel matrix proteins in rats: amelogenin, enamel and ameloblastin. DD-PCR and RT-PCR revealed differential expression of the major proteins from the cap stage to root stage. Immunofluorescence staining results indicated that amelogenin was not detected in either inner enamel epithelium or reduced enamel epithelium, but highly immunoreactive in preameloblasts and ameloblasts; in addition, it was sporadically expressed in preodontoblasts abutting preameloblasts. Ameloblastin expression was also observed in not only differentiated ameloblasts but also osteoblasts. Immunoreactivity to ameloblastin in ameloblasts was strong in Tomes' processes. Enamelin was exclusively localized along the entire newly formed and maturing enamel. Enamelin was largely localized in near Tomes' processes and enamel rods in maturing enamel. Alendronate treatment resulted in down-regulation of amelogenin and ameloblastin at both transcription and translation levels; whereas, enamelin expression was unchanged in response to the treatment. These results suggested that amelogenin, ameloblastin and enamelin might be implicated in cell differentiation, adhesion of ameloblasts to enamel and enamel crystallization during enamel matrix formation, respectively.

Association between ameloblastin gene polymorphisms and the susceptibility to dental Fluorosis / 中华流行病学杂志

Objective To study the distribution of ameloblastin(AMBN) gene polymorphism in coal-fire caused fluorosis (CFCF) in Chongqing municipality and the relationship between AMBN gene polymorphism and the susceptibility to dental fluorosis.Methods Under a case-control study,100 children aged 8-12 and 30 adults with dental fluorosis were enrolled in Wushan and Fengjie counties of Chongqing from December 2010 to February 2011.Another 100 children aged 8-12 and 30 adults with non-dental fluorosis were chosen as internal control groups together with 50 childrenand 30 adults without dental fluorosis were selected as external control groups in the non-epidemic area of Yubei district.DNA was extracted from peripheral blood sample of these people.Genotype of AMBN gene 7 extron 538_540delGGA,10 extron 657A＞G and 13 extron 986C＞T loci were detected using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)technique.Results The rates of 7 extron 538_540delGGA loci among case,internal and external control groups were as follows:GGA/GGA-/-61.2％ (74/121),78.5％ (102/130),74.3％ (52/70) ;GGA/-:24.0％ (29/121),15.4％ (20/130),22.9％ (16/70) ;-/-:14.8％ (18/121),6.1％ (8/130),2.8％ (2/70),the difference was statistically significant (x2=14.353,P＜0.05).The AA appeared to be 86.8％(105/121),93.1％(121/130),91.4％(64/70) and AG were 13.2％(16/121),6.9％(9/130),8.6％ (6/70),with difference not statistically significant (x2=2.972,P＞0.05).CC appeared as 81.0％ (98/121),90.0％(117/130),87.1％(61/70) while CT as 19.0％(23/121),10.0％(13/130),12.9％(9/70),with difference not statistically significant (x2=4.319,P＞0.05).In comparing with the two control groups,the frequency of GGA/GGA was decreasing (x2 values were 8.957,3.405,respectively,P＜0.05) while the frequency of-/-was increasing (x2 values were 5.134,6.833,respectively,P＜0.05).Results from the univariate analysis showed that the individuals who were carrying-/-genotype had an increased risk of suffering from fluorosis (OR values were 2.7,5.9,respectively,P＜0.05).When compared with the internal control group,the CT genotype of case group showed an increase (x2=4.139,P＜0.05) while individuals that carrying CT genotype had an increased risk of suffering from fluorosis (OR=2.1,P＜0.05),in epidemic-area.Conclusion Our results showed that the 7 extron 538_540delGGA and the 13 extron 986C＞T loci polymorphism in AMBN gene might serve as the susceptibility factors causing the coal-fired fluorosis.

Odontogenic Gingival Epithelial Hamartoma; with Reference to the Expression of Ameloblastin Gene by in situ Hybridization and Immunohistochemistry

Odontogenic gingival epithelial hamartoma (OGEH) is an extremely rare lesion characterized by an abnormal proliferation of odontogenic epithelium. This lesion is thought to arise from the rest of the dental lamina lying dormant in the gingival tissue after odontogenesis. Distinguishing OGEH from the granular cell variant of ameloblastoma and central odontogenic fibroma is important. To date, only eleven cases have been reported, and its pathogenesis remains unclear. We report here on a case of OGEH, where the epithelial strands in the lesion were conspicuously positive for the antisera of cytokeratin 19 and ameloblastin. Tumor cells intensely expressed ameloblastin mRNA by in situ hybridization. To the best of our knowledge, this is the first case of OGEH to which ameloblastin immunohistochemical stain and in situ hybridization were applied. Although our study is limited to a single case, the coexpression of cytokeratin 19 and ameloblastin might indicate the origin and specific cytodifferentiation of OGEH is quite different and unique, when contrasted to other odontogenic tumors.