Lactobacillus helveticus Prevents Periodontitis Induced by Aggregatibacter actinomycetemcomitans in Rats by Regulating ß-Defensins.

Objective: To study the preventive effect of Lactobacillus helveticus (L. helveticus) on periodontitis induced by Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) in rats. Methods: Eighteen 8-week-old female rats were randomly divided into three groups: Sham group, Trehalose group, and L. helveticus SBT2171 (LH2171) group. We measured the distance of the cementoenamel junction-alveolar bone crest (CEJ-ABC) to evaluate alveolar bone resorption. Hematoxylin-eosin staining was used to observe the histopathological changes of rat hemimaxillary tissues. We detected the expression of ß-defensins, tumor necrosis factor-α (TNF-α), interleukin- (IL-) 1ß, and IL-6 and the number of A. actinomycetemcomitans in rat gingival tissues by quantitative reverse transcriptase polymerase chain reaction. The levels of IL-1ß, IL-6, and TNF-α in rat gingival tissues were also measured by enzyme-linked immunosorbent assay. Results: Compared with the Trehalose group, the distance of CEJ-ABC was prominently reduced and alveolar bone resorption was notably improved in the LH2171 group. And the infiltration of inflammatory cells in the hemimaxillary tissue decreased obviously, periodontal fibers were arranged neatly, connective tissue small blood vessels proliferated, and the number of A. actinomycetemcomitans reduced significantly in the LH2171 group. In addition, the mRNA expression and release of inflammatory factors in the gingival tissues in the LH2171 group were notably lower than those in the Trehalose group. On the 21st and 36th day, the expression of ß-defensins in the gingival tissue of the LH2171 group increased significantly. Conclusion: L. helveticus improves alveolar bone resorption and increases the expression of ß-defensins thereby inhibiting the number of A. actinomycetemcomitans and thus prevents periodontitis.

[Comparison of subgingival debridement efficacy of air polishing and manual scaling].

PURPOSE: To assess the efficacy of subgingival air polishing and traditional manual scaling in 3-6 mm pockets. METHODS: Patients with chronic periodontitis who were in the maintenance phase were randomly assigned to receive subgingival air polishing (experimental group) and manual scaling (control group) in 4 teeth with probing depths of 3 to 6 mm. Clinical variables including plaque index (PI), probing depth (PD), probing on bleeding (BOP) and gingival recession (GR) were recorded at baseline, 7 and 30 days post-treatment. "Pocket closure" [PD ≤ 4 mm and BOP⁻] was also calculated as supplementary data. The data of the 2 groups were compared using paired t test with SAS 8.2 software package. RESULTS: Thirty-one patients were enrolled and PI was 0.8 during the study. Both treatment procedures resulted in significant reductions of PD at day 7 (P<0.0001). BOP% had significant reduction in the experimental group at day 7 (P=0.0390), but there was no significant difference compared to baseline at day 30. Meanwhile, BOP% in the control group demonstrated downward trends during the study, and significant improvement at day 30. The percentages of sites of "pocket closure" significantly increased in both groups (P=0.0329 and P=0.0035, respectively). CONCLUSIONS: The study indicates that subgingival air polishing and traditional manual scaling are both effective for improving clinical variables during supportive periodontal therapy (SPT) in teeth with probing depths of 3 to 6 mm. But the results reveal no significant difference between the 2 modalities.

A combination of Let-7d, Let-7g and Let-7i serves as a stable reference for normalization of serum microRNAs.

Recent studies have indicated that circulating microRNAs (miRNAs) in serum and plasma are stable and can serve as biomarkers of many human diseases. Measurement of circulating miRNAs with sufficient sensitivity and precision, however, faces some special challenges, among which proper normalization is the most critical but often an underappreciated issue. The primary aim of this study was to identify endogenous reference genes that maintain consistent levels under various conditions to serve as an internal control for quantification of serum miRNAs. We developed a strategy combining Illumina's sequencing by synthesis (SBS) technology, reverse transcription quantitative polymerase chain reaction (RT-qPCR) assay, literature screening and statistical analysis to screen and validate the most suitable reference genes. A combination of let-7d, let-7g and let-7i is selected as a reference for the normalization of serum miRNAs and it is statistically superior to the commonly used reference genes U6, RNU44, RNU48 and miR-16. This has important implications for proper experimental design and accurate data interpretation.

Identification and characterization of microRNAs in raw milk during different periods of lactation, commercial fluid, and powdered milk products.

Recent baby formula milk powder contamination incidents have shown that the classic markers or standards in milk quality control are insufficient in identifying "manipulated" poor-quality milk. In the present study, we demonstrated for the first time that cow milk contains large amounts of microRNAs (miRNAs) and that the unique expression profile of milk-specific miRNAs can serve as a novel indicator and possible new standard for the quality control of raw milk and milk-related commercial products, such as fluid milk and powdered formula milk. First, using Solexa sequencing, we systematically screened miRNA expression in raw milk and identified a total of 245 miRNAs in raw milk. Unlike other classic biomarkers whose expression levels are nearly identical at different periods of lactation, individual miRNAs can be significantly altered during lactation process, implicating that miRNAs may be a more accurate indicator to reflect the quality alteration of milk. Second, using TaqMan probe-based miRNA quantitative RT-PCR, we further identified seven miRNAs that have a relatively consistent expression throughout the lactation process, and more importantly, the expression profile of these seven milk-specific miRNAs can serve as an ideal biomarker for discriminating poor-quality or "manipulated" milk from pure raw milk, as well as for the quality control of commercial milk products, such as fluid milk and powdered formula milk. Together, our findings provide a basis for understanding the physiological role of milk miRNAs and a new potential standard for determining the quality of raw milk or milk-related commercial products.