Periodontitis-induced neuroinflammation impacts dendritic spine immaturity and cognitive impairment.

OBJECTIVE: This study investigated the spinal changes in ligature-induced periodontitis and the role of periodontitis in cognitive impairment. METHODS: Twenty mice were randomized into the control and chronic periodontitis (CP) groups, with the latter receiving ligature-induced periodontitis. Cognitive performance was assessed by fear conditioning test. Periodontal inflammation and alveolar bone resorption were evaluated by micro-computed tomography and histopathology. The hippocampal microglial activation was evaluated by immunohistochemistry (IHC). The expressions of hippocampal cytokines (TNF-α, iNOS, IL-1ß, IL-4, IL-10, and TREM2) were measured by reverse transcription-polymerase chain reaction. The morphology and density of the dendritic spines were determined by Golgi-Cox staining. RESULTS: The CP mice reported significant inflammatory cell infiltration and alveolar bone resorption, with marked increases in cytokine levels (TNF-α, iNOS, IL-1ß, and TREM2) in the brain. Moreover, the CP mice showed significantly reduced freezing to the conditioned stimulus in the cued and contextual tests, indicating impaired memory. Further analyses revealed, in the hippocampus of the CP mice, enhanced microglial activation, decreased dendritic spine density, and increased proportion of thin dendritic spines. CONCLUSIONS: Periodontitis-induced neuroinflammation may impair the cognitive function by activating hippocampal microglia and inducing dendritic spine immaturity.

Disruption of Hedgehog Signaling by Vismodegib Leads to Cleft Palate and Delayed Osteogenesis in Experimental Design.

The function of hedgehog signaling has previously been shown to be crucial for craniofacial development. In this study, we treated C57/BL6J mice with the hedgehog pathway inhibitor vismodegib by oral gavage to establish a stable vismodegib-induced cleft palate model. At E10.5 and E12.5, mice in the experimental group were treated with 100 mg/kg of vismodegib, whereas mice in the control group were treated with solvent. The treated pregnant mice were sacrificed on E13.5, E14.5, E15.5, and E16.5. Palatal shelf growth was evaluated via histological and immunohistochemical analyses as well as palatal organ culture. Immunohistochemical staining was performed to examine the expression of osteogenic proteins in the palatal tissue. A high proportion of the mice administered 2 doses of 100 mg/kg of vismodegib displayed a cleft palate. Histologic examination revealed severely retarded palatal shelf growth and thickened epithelium in the experimental group. Vismodegib exposure induced complete cleft palate, which was attributed to a reduced cell proliferation rate in the palatal mesenchyme along the anterior-posterior axis. Moreover, this model also showed delayed ossification in the region of palatine bone with downregulation of Indian hedgehog (Ihh) protein. Our results suggest that vismodegib can be used to inhibit hedgehog signaling to affect palatal morphogenesis. Under treatment with this exogenous inhibitor, the cell proliferation rate of the palatal shelves and the osteogenic potential of the hard palate were decreased, which likely contributed to the complete cleft palate.

Bone morphogenetic protein type I receptor inhibition induces cleft palate associated with micrognathia and cleft lower lip in mice.

BACKGROUND: Gain-of- and loss-of-function studies have demonstrated that changes in bone morphogenetic protein (BMP) signaling during embryo development cause craniofacial malformations, including cleft palate. It remains uncertain whether BMP signaling could be targeted pharmacologically to affect craniofacial morphogenesis. METHODS: Pregnant C57Bl/6J mice were treated with the BMP type I receptor inhibitor LDN-193189 at the dose of 3, 6, or 9 mg/kg twice a day by intraperitoneal injection from embryonic day 10.5 (E10.5) to E15.5. At E16.5, embryos were investigated by facial measurement analysis and histology to determine the optimal concentration for malformation. Subsequent embryonic phenotypes were analyzed in detail by histology, whole-mount skeletal staining, micro-computed tomography, and palatal organic culture. We further used immunohistochemistry to analyze protein expression of the BMP-mediated canonical and noncanonical signaling components. RESULTS: The optimal concentration of LDN-193189 was determined to be 6 mg/kg. In utero, LDN-193189 exposures induced partial clefting of the anterior palate or complete cleft palate, which was attributed to a reduced cell proliferation rate in the secondary palate, and delayed palatal elevation caused by micrognathia. Analysis of signal transduction in palatal shelves at E12.5 and E13.5 identified a significant reduction of BMP/Smad signaling (p-Smad1/5/8) and unchanged BMP noncanonical signaling (p-p38, p-Erk1/2) after treatment with LDN-193189. CONCLUSION: The results of this study indicate that LDN-193189 can be used to manipulate BMP signaling by selectively targeting the BMP/Smad signaling pathway to affect palatal morphogenesis and produce phenotypes mimicking those caused by genetic mutations. This work established a novel mouse model for teratogen-induced cleft palate. Birth Defects Research (Part A) 106:612-623, 2016. © 2016 Wiley Periodicals, Inc.

Dual-guide template-guided socket-shield preparation and immediate implantation in maxillary anterior region implant surgery.

For immediate implants in the anterior region, the socket-shield technique has received much attention in recent years. However, this technique is technically sensitive and root preparation is difficult. It is also difficult to obtain the ideal three-dimensional position for implant placement in the anterior region. This paper reports a clinical case in which socket-shield preparation and implant cavity preparation were performed with the aid of a dual guide in implant surgery. The dual guide surgical preparation technique was used to reduce the difficulty of socket-shield preparation and to achieve restoration-orientated implant placement with satisfactory clinical results.

CX3C-chemokine receptor 1 modulates cognitive dysfunction induced by sleep deprivation.

BACKGROUND: Microglia plays an indispensable role in the pathological process of sleep deprivation (SD). Here, the potential role of microglial CX3C-chemokine receptor 1 (CX3CR1) in modulating the cognition decline during SD was evaluated in terms of microglial neuroinflammation and synaptic pruning. In this study, we aimed to investigat whether the interference in the microglial function by the CX3CR1 knockout affects the CNS's response to SD. METHODS: Middle-aged wild-type (WT) C57BL/6 and CX3CR1-/- mice were either subjected to SD or allowed normal sleep (S) for 8 h to mimic the pathophysiological changes of middle-aged people after staying up all night. After which, behavioral and histological tests were used to explore their different changes. RESULTS: CX3CR1 deficiency prevented SD-induced cognitive impairments, unlike WT groups. Compared with the CX3CR1-/- S group, the CX3CR1-/- SD mice reported a markedly decreased microglia and cellular oncogene fos density in the dentate gyrus (DG), decreased expression of pro-inflammatory cytokines, and decreased microglial phagocytosis-related factors, whereas increased levels of anti-inflammatory cytokines in the hippocampus and a significant increase in the density of spines of the DG were also noted. CONCLUSIONS: These findings suggest that CX3CR1 deficiency leads to different cerebral behaviors and responses to SD. The inflammation-attenuating activity and the related modification of synaptic pruning are possible mechanism candidates, which indicate CX3CR1 as a candidate therapeutic target for the prevention of the sleep loss-induced cognitive impairments.