Porphyromonas gingivalis infection increases osteoclastic bone resorption and osteoblastic bone formation in a periodontitis mouse model.

BACKGROUND: Porphyromonas gingivalis has been shown to invade osteoblasts and inhibit their differentiation and mineralization in vitro. However, it is unclear if P. gingivalis can invade osteoblasts in vivo and how this would affect alveolar osteoblast/osteoclast dynamics. This study aims to answer these questions using a periodontitis mouse model under repetitive P. gingivalis inoculations. METHODS: For 3-month-old BALB/cByJ female mice, 10(9) CFU of P. gingivalis were inoculated onto the gingival margin of maxillary molars 4 times at 2-day intervals. After 2 weeks, another 4 inoculations at 2-day intervals were applied. Calcein was injected 7 and 2 days before sacrificing animals to label the newly formed bone. Four weeks after final inoculation, mice were sacrificed and maxilla collected. Immunohistochemistry, micro-CT, and bone histomorphometry were performed on the specimens. Sham infection with only vehicle was the control. RESULTS: P. gingivalis was found to invade gingival epithelia, periodontal ligament fibroblasts, and alveolar osteoblasts. Micro-CT showed alveolar bone resorption and significant reduction of bone mineral density and content in the infected mice compared to the controls. Bone histomorphometry showed a decrease in osteoblasts, an increase in osteoclasts and bone resorption, and a surprisingly increased osteoblastic bone formation in the infected mice compared to the controls. CONCLUSIONS: P. gingivalis invades alveolar osteoblasts in the periodontitis mouse model and cause alveolar bone loss. Although P. gingivalis appears to suppress osteoblast pool and enhance osteoclastic bone resorption, the bone formation capacity is temporarily elevated in the infected mice, possibly via some anti-microbial compensational mechanisms.

Smart salt-responsive thread for highly sensitive microfluidic glucose detection in sweat.

Thread-based microfluidic colorimetric sensors have been deemed a potential tool that may be incorporated into textiles for non-invasive sweat analysis. Nevertheless, their poor performance significantly limits their practical uses in sweat glucose detection down to 20 µM. Herein, a microfluidic glucose sensing device containing a salt-responsive thread is developed for the highly sensitive detection of glucose in human sweat. By grafting a zwitterionic polymer brush-which could react to ionic strength by changing the conformation of the polymer chains from the collapsing state to the stretching state-onto the cotton thread, the salt-responsive thread was created. Compared to the pristine cotton thread, the modified thread has better ion-capture capabilities, a more noticeable swelling effect, and a higher ability to absorb water. These enable a significant enrichment of glucose when the saline solution passes through it. The salt-responsive thread was employed to construct a thread/paper-based microfluidic sensing device for the monitoring of glucose in artificial sweat, exhibiting a sensitivity of -0.255 µM-1 and a detection limit of 14.7 µM. In comparison to the pristine cotton thread-based device, the performance is significantly superior. Using a hydrophobic fabric and salt-responsive threads, a glucose-sensing headband was prepared for on-body sweat glucose monitoring. With the use of a smartphone-based image analysis system, the headband can detect the concentration of glucose in a volunteer's perspiration. Using the thread-based salt-responsive zwitterionic polymer brush might offer a novel approach to creating wearable sweat sensors with extremely high sensitivity.

Integrin α5ß1-fimbriae binding and actin rearrangement are essential for Porphyromonas gingivalis invasion of osteoblasts and subsequent activation of the JNK pathway.

BACKGROUND: Chronic periodontitis is an infectious disease of the periodontium, which includes the gingival epithelium, periodontal ligament and alveolar bone. The signature clinical feature of periodontitis is resorption of alveolar bone and subsequent tooth loss. The Gram-negative oral anaerobe, Porphyromonas gingivalis, is strongly associated with periodontitis, and it has been shown previously that P. gingivalis is capable of invading osteoblasts in a dose- and time-dependent manner resulting in inhibition of osteoblast differentiation and mineralization in vitro. It is not yet clear which receptors and cytoskeletal components mediate the invasive process, nor how the signaling pathways and viability of osteoblasts are affected by bacterial internalization. This study aimed to investigate these issues using an in vitro model system involving the inoculation of P. gingivalis ATCC 33277 into primary osteoblast cultures. RESULTS: It was found that binding between P. gingivalis fimbriae and integrin α5ß1 on osteoblasts, and subsequent peripheral condensation of actin, are essential for entry of P. gingivalis into osteoblasts. The JNK pathway was activated in invaded osteoblasts, and apoptosis was induced by repeated infections. CONCLUSIONS: These observations indicate that P. gingivalis manipulates osteoblast function to promote its initial intracellular persistence by prolonging the host cell life span prior to its intercellular dissemination via host cell lysis. The identification of molecules critical to the interaction between P. gingivalis and osteoblasts will facilitate the development of new therapeutic strategies for the prevention of periodontal bone loss.

Weavable yarn-shaped supercapacitor in sweat-activated self-charging power textile for wireless sweat biosensing.

The yarn-based sweat-activated battery (SAB) is a promising energy source for textile electronics due to its excellent skin compatibility, great weavability, and stable electric output. However, its power density is too low to support real-time monitoring and wireless data transmission. Here, we developed a scalable, high-performance sweat-based yarn biosupercapacitor (SYBSC) with two symmetrically aligned electrodes made by wrapping hydrophilic cotton fibers on polypyrrole/poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate)-modified stainless steel yarns. Once activated with artificial sweat, the SYBSC could offer a high areal capacitance of 343.1 mF cm-2 at 0.5 mA cm-2. After 10,000 times of bending under continuous charge-discharge cycles and 25 cycles of machine washing, the device could retain the capacitance at rates of 68% and 73%, respectively. The SYBSCs were integrated with yarn-shaped SABs to produce hybrid self-charging power units. The hybrid units, pH sensing fibers, and a mini-analyzer were woven into a sweat-activated all-in-one sensing textile, in which the hybrid, self-charging units could power the analyzer for real-time data collection and wireless transmission. The all-in-one electronic textile could be successfully employed to real-time monitor the pH values of the volunteers' sweat during exercise. This work can promote the development of self-charging electronic textiles for monitoring human healthcare and exercise intensity.

Constructing Silk Fibroin-Based Three-Dimensional Microfluidic Devices via a Tape Mask-Assisted Multiple-Step Etching Technique.

Regenerated silk fibroin (RSF) has been regarded as a very promising biomaterial for the preparation of microfluidic devices. However, the facile and low-cost fabrication of three-dimensional (3D) RSF microfluidic devices is still a great challenge. Herein, we developed a tape-mask-assisted multiple-step etching technique to fabricate 3D microfluidic devices based on water-annealed RSF films. Several rounds of tape adhesion- or peeling-etching cycles need to be conducted to produce 3D features on the RSF films with the LiBr aqueous solution as the etchant. The water-annealed RSF films could be effectively etched with 1.0 g·mL-1 LiBr solution at 60 °C. The shape, width, and height of the 3D structures could be precisely tailored by controlling the mask pattern, etching conditions, and the number of etchings. Using the tape adhesion- and peeling-assisted multiple-etching techniques, the convex-pyramid-shaped and the concave-step-shaped structures could be successfully prepared on the RSF films, respectively. The RSF-film-based 3D micromixers and microfluidic separator were also manufactured with the proposed approach, exhibiting excellent liquid mixing and size-dependent particle sorting capabilities, respectively. The enzymatic degradation of RSF-film-based devices was also investigated to show their environmental friendliness. This work may not only provide a facile and low-cost method for the fabrication of RSF-based 3D microfluidic devices but also extend the applications of RSF in the fields of biomedical and chemical analysis.

Odontoblast-targeted Bcl-2 overexpression impairs dentin formation.

Apoptosis has been described extensively in tooth development, which is under tight control of multiple apoptosis regulators, including anti-apoptotic protein Bcl-2. However, it is totally unclear how Bcl-2 is related to odontogenesis, especially dentinogenesis. Using a transgenic mouse Col2.3Bcl-2 in which human Bcl-2 was overexpressed in odontoblasts, the effect of Bcl-2 on dentinogenesis was investigated. Overexpression of Bcl-2 was detected by immunohistochemistry and Western blot. Odontoblast apoptosis was evaluated by TUNEL and Western blot detection of cleaved caspase-3. Odontoblast differentiation was assessed by real-time PCR detection of dentin matrix expression. Dentin mineralization was evaluated by micro-CT in vivo, and alizarin red S staining and calcium content analysis in vitro. Bcl-2 was found to be overexpressed in odontoblasts and prevent their apoptosis. Odontoblast differentiation and mineralization was inhibited by Bcl-2, as evidenced by lower expressions of DMP-1, OC, and DSPP, and decreased odontoblast mineralization in vitro, as well as decreased dentin thickness and mineral density in vivo when compared to the wild-type animals. Inhibition of odontoblast differentiation by Bcl-2 occurs, at least partially, via a suppression of MEK-ERK1/2 signaling pathway. In conclusion, Bcl-2 overexpression prevents odontoblast apoptosis and impairs dentin formation, partially via an inhibition of odontoblast differentiation. This study revealed some novel functions of Bcl-2 in dentinogenesis in addition to its anti-apoptotic effect, which shed some light on the genetic complexity of tooth development.

Efficacy and safety of a mammalian target of rapamycin inhibitor in pediatric patients with tuberous sclerosis complex: A systematic review and meta-analysis.

Inhibitors of mammalian target of rapamycin (mTOR) are increasingly used as therapy for pediatric patients with tuberous sclerosis complex (TSC). The uncertainty over the efficacy and safety of mTOR inhibitor therapy for the treatment of pediatric patients with TSC emphasizes the necessity for a synthesis of existing evidence. The aim of this study was to assess the efficacy and safety of mTOR inhibitor therapy for the treatment of pediatric patients with TSC. The PubMed, EmBase and Cochrane Library electronic databases were searched, and studies of mTOR inhibitor therapy and non-mTOR inhibitor therapy in pediatric patients with TSC (<18 years old) were selected. Eleven studies met the inclusion criteria. There was evidence of a significantly increased response rate in pediatric patients with TSC treated with mTOR inhibitor therapy compared with those treated with non-mTOR inhibitor therapy (odds ratio, 24.71; 95% confidence interval, 7.46-81.72; P<0.001). The majority of studies reported few adverse events. There was an increased incidence of mouth ulceration, stomatitis, convulsion and pyrexia in pediatric patients with TSC treated with mTOR inhibitor therapy. In conclusion, mTOR inhibitor therapy is an efficacious and safe treatment for pediatric patients with TSC.

[Analysis of the infection status of saliva Helicobacter pylori in Lanzhou].

OBJECTIVE: To determine the prevalence of saliva Helicobacter pylori in Lanzhou and investigate Helicobacter pylori-related diseases. METHODS: Helicobacter pylori was detected through bacterial culture, Gram stain microscopy, and urease test from saliva samples collected from 941 residents of Lanzhou. The infection rate and growth of Helicobacter pylori among the residents were analyzed in terms of different oral health conditions, oral disease, gender, urban and rural status, and age. RESULTS: The rate of Helicobacter pylori-positive saliva in Lanzhou was 42.72%. The status of Helicobacter pylori infection showed significant difference among subjects with different oral hygiene and oral diseases. The rate of Helicobacter pylori-positive saliva among females was 47.89%, which was greater compared with the rate among males (38.45%, P = 0.004, chi2 = 8.492). The rate of Helicobacter pylori-positive saliva in the town was 33.99%, which was less than the rate for the villages (50.93%, P = 0.000, chi2 = 27.551). The rate of Helicobacter pylori-positive saliva among residents aged 10 to 59 showed a flat trend with no significant differences. However, the rate of Helicobacter pylori-positive saliva among residents over 60 years old showed a significant increase. No significant difference was found in the growth of saliva Helicobacter pylori (P = 0.086). CONCLUSION: The rate of Helicobacter pylori-positive saliva is related to the subjects' oral hygiene, oral disease, gender, age, and living conditions.

Odontoblast-targeted Bcl-2 overexpression promotes dentine damage repair.

OBJECTIVE: Bcl-2 is widely expressed in a developing tooth organ and regulates tooth morphogenesis. However, whether Bcl-2 is related to tooth damage repair is unknown yet. Using an odontoblast-targeted Bcl-2 overexpression transgenic mouse (Col2.3Bcl-2) and artificial cavity preparation as a model system, the relationship between Bcl-2 and reparative dentinogenesis is investigated in this study. METHODS: The odontoblastic-like cell cultures derived from mouse molar pulps were established. The expression of transgenic human Bcl-2 (hBcl-2) and endogenous mouse Bcl-2 (mBcl-2) and mouse Bax (mBax, a Bcl-2 antagonist) was detected in vivo and in vitro by Western blot and immunocytochemistry, respectively. Basal level and artificial cavity-induced odontoblast apoptosis was detected by the Deoxynucleotidyl Transferase (TdT) dUTP Nick End labelling (TUNEL) technique. Reparative dentine formation induced by artificial cavity drilled to a half dentine thickness on mesial cervical region of mandibular first molars 2, 4, and 6 weeks post-op was evaluated histologically and via micro-CT. RESULTS: The transgenic hBcl-2 was stably expressed in odontoblasts of the transgenic animals without interference with the expression of mBcl-2 and mBax. Basal level as well as artificial cavity- induced odontoblast apoptosis was prevented by the transgene. Compared to the wild type, the transgenic animals produced reparative dentine with significantly higher mineral density 6 weeks after the operation. CONCLUSIONS: Bcl-2 overexpression prevents odontoblast apoptosis and promotes dentine damage repair, indicating that genetic manipulation of Bcl-2 may be a novel strategy to maintain the vitality and function of dentine-pulp complex under detrimental mechanical stimuli.

Fimbriae of Porphyromonas gingivalis are important for initial invasion of osteoblasts, but not for inhibition of their differentiation and mineralization.

BACKGROUND: Porphyromonas gingivalis is etiologically associated with chronic periodontitis. The major fimbriae of this periodontal pathogen mediate binding to host gingival epithelial cells and fibroblasts, a critical function in the initiation of periodontitis. However, the role of fimbriae in P. gingivalis-osteoblast interactions remains unknown. In the present study, the involvement of major fimbriae in the initial and long-term interactions between P. gingivalis and osteoblasts is investigated. METHODS: Primary mouse calvarial osteoblast cultures were established and inoculated with P. gingivalis ATCC 33277 or YPF1, a major fimbriae-deficient mutant of P. gingivalis. Confocal microscopy images were acquired to assess bacterial invasion. DNA content measurement, real-time polymerase chain reaction, and alizarin red S staining and calcium content analysis were used to study the impact of bacteria on the proliferation, differentiation, and mineralization of osteoblasts, respectively. RESULTS: Compared to the parent strain, YPF1 was significantly reduced in invasion of osteoblasts after 3 hours interaction. However, extended culture of infected osteoblasts did not reveal significant differences in persistence between the two strains. Proliferation of osteoblasts was not affected by either strain, and differentiation and mineralization of osteoblasts were inhibited by both strains to comparable levels. CONCLUSION: This study reveals that major fimbriae are involved in the initial invasion of osteoblasts by P. gingivalis, but are not essential for the subsequent inhibition of osteoblast differentiation and mineralization in long-term culture.

Porphyromonas gingivalis invades osteoblasts and inhibits bone formation.

Porphyromonas gingivalis is etiologically associated with adult periodontitis, but it is unclear how P. gingivalis long-term interactions with bone cells contribute to this disease. This study investigates P. gingivalis interactions with osteoblasts over an extended time course. A primary mouse calvarial osteoblast culture was established and inoculated with P. gingivalis 33277 repeatedly every other day for up to four weeks. Invasion of osteoblasts by P. gingivalis, and the resulting effects on the proliferation, differentiation, and mineralization of osteoblasts were evaluated. P. gingivalis was found to invade osteoblasts in a dose-dependent manner, and repetitive inoculation increased the percentage of osteoblasts with internalized P. gingivalis. P. gingivalis did not affect osteoblast proliferation, but inhibited their differentiation and mineralization, partially via an inhibition of the differentiation regulatory transcription factors Cbfa-1 and osterix. In conclusion, P. gingivalis invades osteoblasts and inhibits bone formation, which likely contributes to alveolar bone loss in chronic periodontitis.