Role of Candida albicans-secreted aspartyl proteinases (Saps) in severe early childhood caries.

Candida albicans is strongly associated with severe early childhood caries (S-ECC). However, the roles of secreted aspartyl proteinases (Saps), an important virulence factor of C. albicans, in the progress of S-ECC are not clear. In our study, the Saps activities were evaluated by the yeast nitrogen base-bovine serum albumi (YNB-BSA) agar plate method and by the MTT method with bovine serum albumin (BSA) as the substrate. Genotypes of C. albicans and gene expression of Sap1-5 were evaluated. The relationships of Saps activities and genotypes with S-ECC were analyzed. The results showed that enzyme activities of Saps in the S-ECC group were significantly higher than those in the caries free (CF) group (p<0.05). Genotypes A, B and C were detected in the S-ECC group, and genotypes A and C were detected in the CF group. In the genotype A group, Saps activity in the S-ECC group was significantly different from that in the CF group (p<0.05). The gene expression level of Sap1 in the S-ECC group was significantly higher than that in the CF group (p=0.001), while Sap4 expression was significantly lower than that in the CF group (p=0.029). It can be concluded that Sap1-5 are the predominant proteinase genes expressed in C. albicans from dental biofilm and Sap1 may play an important role in the development of S-ECC.