Evaluation of microbiome in primary and permanent dentition in grade C periodontitis in young individuals.

BACKGROUND: The aim of the present study was to evaluate the subgingival microbiome in patients with grade C molar-incisor pattern periodontitis (C-MIP) affecting the primary or permanent dentitions. METHODS: DNA was isolated from subgingival biofilm samples from diseased and healthy sites from 45 C-MIP patients and subjected to phylogenetic microarray analysis. C-MIP sites were compared between children affected in the primary to those affected in the permanent dentitions. Within-subject differences between C-MIP-affected sites and dentition-matched healthy sites were also evaluated. RESULTS: C-MIP sites of subjects affected in the primary dentition showed partially overlapping but distinct microbial communities from C-MIP permanent dentition sites (p < 0.05). Differences were due to increased levels in primary C-MIP sites of certain species of the genera Capnocytophaga and Leptotrichia, while C-MIP permanent dentition sites showed higher prevalence of Filifactor alocis. Aggregatibacter actinomycetemcomitans (Aa) was among species seen in high prevalence and levels in both primary and permanent C-MIP sites. Moreover, both permanent and primary C-MIP sites showed distinct microbial communities when compared to dentition-matched healthy sites in the same subject (p < 0.01). CONCLUSIONS: Primary and permanent teeth with C-MIP showed a dysbiotic microbiome, with children affected in the primary dentition showing a distinct profile from those affected in the permanent dentition. However, Aa was enriched in both primary and permanent diseased sites, confirming that this microorganism is implicated in C-MIP in both dentitions.

Periodontal Disease in the COVID-19 Era: Potential Reservoir and Increased Risk for SARS-CoV-2

Abstract Since December 2019, an outbreak of Coronavirus Disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in China and is now becoming a global Pandemic, with over 10.5 million cases worldwide. Angiotensin-converting enzyme-2 (ACE-2) has been considered the main receptor for the SARS-CoV-2 entry into human cells, and they are known to be present not only in lungs (therefore the common viral pneumonia) but also in nasopharyngeal mucosa, salivary cells and oral epithelial cells. Moreover, there seems to be recent evidence showing that the crevicular fluid on the periodontal pockets of patients presenting periodontitis could harbor SARS-CoV-2 and act as a potential reservoir for increased viral load in the oral cavity of COVID-positive patients. Additionally, sites with active periodontal disease might contribute for virus binding and tissue infection due to elevated expression of furin and cathepsin L proteases, which play a major role in enabling the SARS-CoV-2 to bind ACE-2 receptors and facilitating endosomal fusion in the host cells. Taken together this news and views article highlight possible virus reservoirs in COVID-positive patients, as well as increased risk for infection in patients with active periodontal disease, further proposing potential targets for antiviral intervention on SARS-CoV-2 infection.

Investigation of Rett syndrome using pluripotent stem cells.

Rett syndrome (RTT) is one of most prevalent female neurodevelopmental disorders. De novo mutations in X-linked MECP2 are mostly responsible for RTT. Since the identification of MeCP2 as the underlying cause of RTT, murine models have contributed to understanding the pathophysiology of RTT and function of MeCP2. Reprogramming is a procedure to produce induced pluripotent stem cells (iPSCs) by overexpression of four transcription factors. iPSCs obtain similar features as embryonic stem cells and are capable of self-renewing and differentiating into cells of all three layers. iPSCs have been utilized in modeling human diseases in vitro. Neurons differentiated from RTT-iPSCs showed the recapitulation of RTT phenotypes. Despite the early success, genetic and epigenetic instability upon reprogramming and ensuing maintenance of iPSCs raise concerns in using RTT-iPSCs as an accurate in vitro model. Here, we update the current iPSC-based RTT modeling, and its concerns and challenges.