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A spatial gradient of bacterial diversity in the human oral cavity shaped by salivary flow.
Proctor, DM, Fukuyama, JA, Loomer, PM, Armitage, GC, Lee, SA, Davis, NM, Ryder, MI, Holmes, SP, Relman, DA
Nature communications. 2018;9(1):681
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Plain language summary
Identifying spatial patterns in the human microbiota is necessary to provide insight into mechanisms that either maintain or disrupt its healthy state. The aim of this study was to identify the type and extent of oral spatial patterns formed by bacterial communities, as well as observe the impact of low salivary flow on the spatial patterns. Dental exams were performed on 31 participants to evaluate the oral health status and follow-up was dependent on group allocation. This study found bacterial communities were distinguishable depending on types of teeth and tissue. Further, bacteria on soft and hard tissues varied across the front and back of the oral cavity in a gradient-manner, implying that salivary flow plays a role in establishing the bacterial community gradient in the oral cavity. Based on these results, the authors recommend spatial patterns and processes be explored in other body parts to better understand health and disease.
Abstract
Spatial and temporal patterns in microbial communities provide insights into the forces that shape them, their functions and roles in health and disease. Here, we used spatial and ecological statistics to analyze the role that saliva plays in structuring bacterial communities of the human mouth using >9000 dental and mucosal samples. We show that regardless of tissue type (teeth, alveolar mucosa, keratinized gingiva, or buccal mucosa), surface-associated bacterial communities vary along an ecological gradient from the front to the back of the mouth, and that on exposed tooth surfaces, the gradient is pronounced on lingual compared to buccal surfaces. Furthermore, our data suggest that this gradient is attenuated in individuals with low salivary flow due to Sjögren's syndrome. Taken together, our findings imply that salivary flow influences the spatial organization of microbial communities and that biogeographical patterns may be useful for understanding host physiological processes and for predicting disease.
2.
The ionic products of bioactive glass particle dissolution enhance periodontal ligament fibroblast osteocalcin expression and enhance early mineralized tissue development.
Varanasi, VG, Owyoung, JB, Saiz, E, Marshall, SJ, Marshall, GW, Loomer, PM
Journal of biomedical materials research. Part A. 2011;(2):177-84
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Abstract
This study resulted in enhanced collagen type 1 and osteocalcin expression in human periodontal ligament fibroblasts (hPDLF) when exposed to bioactive glass conditioned media that subsequently may promote early mineralized tissue development. Commercial Bioglass™ (45S5) and experimental bioactive coating glass (6P53-b), were used to make a glass conditioned media (GCM) for comparison to control medium. ICP-MS analysis showed increased concentrations of Ca(2+), PO(4) (3-), Si(4+), and Na(+), for 45S5 GCM and Mg(2+), K(+), Ca(2+), PO(4)(3-), Si(4+), and Na(+) for 6P53-b GCM (relative to control medium). Differentiating hPDLF cultures exposed to 45S5 and 6P53-b GCM showed enhanced expression of collagen type 1 (Col1α1, Col1α2), osteocalcin, and alkaline phosphatase gene expression. These GCM also enhanced osteocalcin protein expression. After 16 d of culture, 45S5 and 6P53-b GCM treated cells showed regions of deep red Alizarin staining, indicating increased Ca within their respective extracellular matrices (ECM), while control-treated cells did not exhibit these features. SEM analysis showed more developed ECM in GCM treated cultures, indicated by multiple tissue layering and abundant collagen fiber bundle formation, while control treated cells did not exhibit these features. SEM analysis showed polygonal structures suggestive of CaP in 45S5 GCM treated cultures. These results indicate the osteogenic potential of bioactive coating glass in periodontal bone defect filling applications.