Association between Periodontitis and Mild Cognitive Impairment: A Systematic Review and Meta-Analysis.

INTRODUCTION: The connection between periodontitis and mild cognitive impairment (MCI) continues to receive attention. However, whether periodontitis is a risk factor for MCI remains still uncertain. This study aims to systematically analyze the available literature regarding the relationship between periodontitis and the risk of developing MCI and whether the periodontal health of MCI patients is poorer. METHODS: A literature search of PubMed, Scopus, Embase, and Web of Science databases was conducted to include all studies on the relationship between periodontitis and MCI from inception to April 2023. The studies were independently screened by 2 researchers, and those meeting the inclusion criteria were extracted and cross-checked. Pooled odds ratio (OR) or mean difference (MD) with 95% confidence intervals (CI) was calculated using either a fixed-effects or random-effects model. RESULTS: Seven studies with a total of 3,973 participants were included. Meta-analysis results showed a statistically significant higher incidence of MCI in patients with periodontitis (OR, 1.70 (95% CI: 1.24-2.32, p < 0.001) compared to healthy participants. A subgroup meta-analysis showed that the pooled OR for the risk of MCI in patients with severe periodontitis was 2.09 (95% CI: 1.49-2.92, p < 0.001). In addition, attachment loss (MD = 0.44, 95% CI: 0.12-0.75, p < 0.001) and plaque index (MD = 0.72, 95% CI: 0.50-0.93, p < 0.001) were higher in MCI patients compared with the control group, but the pocket probing depth (MD = 0.21, 95% CI: -0.08 to 0.49, p = 0.15) was not significantly different between the two groups. CONCLUSIONS: Patients with periodontitis are at a higher risk of developing MCI, and the periodontal health of MCI patients is generally compromised. However, further well-designed studies should be conducted to confirm this relationship between MCI and periodontitis.

Quercetin prevents osteoarthritis progression possibly via regulation of local and systemic inflammatory cascades.

Due to the lack of effective treatments, osteoarthritis (OA) remains a challenge for clinicians. Quercetin, a bioflavonoid, has shown potent anti-inflammatory effects. However, its effect on preventing OA progression and the underlying mechanisms are still unclear. In this study, Sprague-Dawley male rats were divided into five groups: control group, OA group (monosodium iodoacetate intra-articular injection), and three quercetin-treated groups. Quercetin-treated groups were treated with intragastric quercetin once a day for 28 days. Gross observation and histopathological analysis showed cartilage degradation and matrix loss in the OA group. High-dose quercetin-group joints showed failure in OA progression. High-dose quercetin inhibited the OA-induced expression of MMP-3, MMP-13, ADAMTS4, and ADAMTS5 and promoted the OA-reduced expression of aggrecan and collagen II. Levels of most inflammatory cytokines and growth factors tested in synovial fluid and serum were upregulated in the OA group and these increases were reversed by high-dose quercetin. Similarly, subchondral trabecular bone was degraded in the OA group and this effect was reversed in the high-dose quercetin group. Our findings indicate that quercetin has a protective effect against OA development and progression possibly via maintaining the inflammatory cascade homeostasis. Therefore, quercetin could be a potential therapeutic agent to prevent OA progression in risk groups.

NF-κB Activator 1 downregulation in macrophages activates STAT3 to promote adenoma-adenocarcinoma transition and immunosuppression in colorectal cancer.

BACKGROUND: Adenoma-adenocarcinoma transition is a key feature of colorectal cancer (CRC) occurrence and is closely regulated by tumor-associated macrophages (TAMs) and CD8+ T cells. Here, we investigated the effect of the NF-κB activator 1 (Act1) downregulation of macrophages in the adenoma-adenocarcinoma transition. METHODS: This study used spontaneous adenoma-developing ApcMin/+, macrophage-specific Act1-knockdown (anti-Act1), and ApcMin/+; anti-Act1 (AA) mice. Histological analysis was performed on CRC tissues of patients and mice. CRC patients' data retrieved from the TCGA dataset were analyzed. Primary cell isolation, co-culture system, RNA-seq, and fluorescence-activated cell sorting (FACS) were used. RESULTS: By TCGA and TISIDB analysis, the downregulation of Act1 expression in tumor tissues of CRC patients negatively correlated with accumulated CD68+ macrophages in the tumor. Relative expression of EMT markers in the tumor enriched ACT1lowCD68+ macrophages of CRC patients. AA mice showed adenoma-adenocarcinoma transition, TAMs recruitment, and CD8+ T cell infiltration in the tumor. Macrophages depletion in AA mice reversed adenocarcinoma, reduced tumor amounts, and suppressed CD8+ T cell infiltration. Besides, macrophage depletion or anti-CD8a effectively inhibited metastatic nodules in the lung metastasis mouse model of anti-Act1 mice. CRC cells induced activation of IL-6/STAT3 and IFN-γ/NF-κB signaling and the expressions of CXCL9/10, IL-6, and PD-L1 in anti-Act1 macrophages. Anti-Act1 macrophages facilitated epithelial-mesenchymal-transition and CRC cells' migration via CXCL9/10-CXCR3-axis. Furthermore, anti-Act1 macrophages promoted exhaustive PD1+ Tim3+ CD8+ T cell formation. Anti-PD-L1 treatment repressed adenoma-adenocarcinoma transition in AA mice. Silencing STAT3 in anti-Act1 macrophages reduced CXCL9/10 and PD-L1 expression and correspondingly inhibited epithelial-mesenchymal-transition and CRC cells' migration. CONCLUSIONS: Act1 downregulation in macrophages activates STAT3 that promotes adenoma-adenocarcinoma transition via CXCL9/10-CXCR3-axis in CRC cells and PD-1/PD-L1-axis in CD8+ T cells.

Dental pulp stem cell-derived exosomes revitalize salivary gland epithelial cell function in NOD mice via the GPER-mediated cAMP/PKA/CREB signaling pathway.

BACKGROUND: Restoration of salivary gland function in Sjogren's syndrome (SS) is still a challenge. Dental pulp stem cells (DPSCs) derived exosomes had shown anti-inflammatory, anti-oxidative, immunomodulatory, and tissue function restorative abilities. However, the salivary gland function restoration potential of DPSCs-derived exosomes (DPSC-Exos) during SS has not been investigated yet. METHODS: DPSC-Exos was isolated by ultracentrifugation methods and characterized. Salivary gland epithelial cells (SGEC) were treated with interferon-gamma (IFN-γ) to mimic SS in vitro and cultured with or without DPSC-Exos. SGEC survival and aquaporin 5 (AQP5) expression were analyzed. mRNA sequencing and bioinformatics analysis were performed in IFN-γ vs. DPSC-Exos+ IFN-γ treated SGEC. Non-obese diabetic (NOD)/ltj female mice (SS model), were intravenously administered with DPSC-Exos, and salivary gland functions and SS pathogenicity were analyzed. Furthermore, the mRNA sequencing and bioinformatics predicted mechanism of the therapeutic effect of DPSC-Exos was further investigated both in vitro and in vivo using RT-qPCR, Western blot, immunohistochemistry, immunofluorescence, flowcytometry analysis. RESULTS: DPSC-Exos partially rescued IFN-γ triggered SGEC death. IFN-γ inhibited AQP5 expression in SGEC and DPSC-Exos reversed this effect. Transcriptome analysis showed GPER was the upregulated DEG in DPSC-Exos-treated SGEC with a positive correlation with salivary secretion-related DEGs. Pathway enrichment analysis revealed that DEGs were mainly attributed to estrogen 16 alpha-hydroxylase activity, extracellular exosome function, cAMP signaling, salivary secretion, and estrogen signaling. Intravenous injection of DPSC-Exos in NOD/ltj mice alleviated the SS syndrome as indicated by the increased salivary flow rate, attenuated glandular inflammation, and increased AQP5 expression. GPER was also upregulated in the salivary gland of DPSC-Exos-treated NOD/ltj mice compared with the PBS-treated NOD/ltj mice. IFN-γ+DPSC-Exos-treated SGEC showed higher expression of AQP5, p-PKA, cAMP, and intracellular Ca2+ levels compared with IFN-γ-treated SGEC. These effects were reversed by the inhibition of GPER. CONCLUSIONS: Our results showed that DPSC-Exos revitalize salivary gland epithelial cell function during SS via the GPER-mediated cAMP/PKA/CREB pathway suggesting the possible therapeutic potential of DPSC-Exos in SS-treatment.

Leptin-deficient ob/ob mice exhibit periodontitis phenotype and altered oral microbiome.

BACKGROUND AND OBJECTIVE: Leptin-deficient obesity is associated with various systemic diseases including diabetes and low bone mass phenotype. However, the periodontal status of leptin-deficient obese individuals is still unclear. In this study, we aimed to analyze the periodontal status, alveolar bone phenotype, and oral microbiome status in leptin-deficient obese mice (ob/ob mice). METHODS: This study used 12-week-old wild-type and ob/ob male mice. The alveolar bone phenotype and periodontal status in the maxilla were analyzed by micro-CT and histological analysis. Osteoclasts in alveolar bone were visualized by TRAP staining. Expressions of inflammatory markers (MMP-9, IL-1ß, and TGF-ß1) and osteoclastogenic markers (RANKL and OPG) in periodontium were analyzed by immunohistochemistry and RT-qPCR. The oral microbiome was analyzed by 16 S rDNA sequencing. RESULTS: CEJ-ABC distance in maxillary molars (M1-M3) of ob/ob mice was significantly higher compared with that of wild-type. The alveolar bone BV/TV ratio was reduced in ob/ob mice compared with wild-type. Higher numbers of osteoclasts were observed in ob/ob mice alveolar bone adjacent to the molar root. Epithelial hyperplasia in gingiva and disordered periodontal ligaments was observed in ob/ob mice. RANKL/OPG expression ratio was increased in ob/ob mice compared with wild-type. Expressions of inflammatory markers MMP-9, IL-1ß, and TGF-ß1 were increased in ob/ob mice compared with wild-type. Oral microbiome analysis showed that beneficial bacteria Akkermansia and Ruminococcaceae_UCG_014 were more abundant in the wild-type mice while the inflammation-related Flavobacterium was more abundant in ob/ob mice. CONCLUSION: In conclusion, ob/ob mice showed higher expressions of inflammatory factors, increased alveolar bone loss, lower abundance of the beneficial bacteria, and higher abundance of inflammatory bacteria in the oral cavity, suggesting leptin-deficient obesity as a risk factor for periodontitis development in ob/ob mice.

Apoptotic bodies: bioactive treasure left behind by the dying cells with robust diagnostic and therapeutic application potentials.

Apoptosis, a form of programmed cell death, is essential for growth and tissue homeostasis. Apoptotic bodies (ApoBDs) are a form of extracellular vesicles (EVs) released by dying cells in the last stage of apoptosis and were previously regarded as debris of dead cells. Recent studies unraveled that ApoBDs are not cell debris but the bioactive treasure left behind by the dying cells with an important role in intercellular communications related to human health and various diseases. Defective clearance of ApoBDs and infected-cells-derived ApoBDs are possible etiology of some diseases. Therefore, it is necessary to explore the function and mechanism of the action of ApoBDs in different physiological and pathological conditions. Recent advances in ApoBDs have elucidated the immunomodulatory, virus removal, vascular protection, tissue regenerative, and disease diagnostic potential of ApoBDs. Moreover, ApoBDs can be used as drug carriers enhancing drug stability, cellular uptake, and targeted therapy efficacy. These reports from the literature indicate that ApoBDs hold promising potential for diagnosis, prognosis, and treatment of various diseases, including cancer, systemic inflammatory diseases, cardiovascular diseases, and tissue regeneration. This review summarizes the recent advances in ApoBDs-related research and discusses the role of ApoBDs in health and diseases as well as the challenges and prospects of ApoBDs-based diagnostic and therapeutic applications.

Upregulation of estrogen receptor alpha (ERα) expression in transgenic mice expressing human CYP4Z1.

PURPOSE: CYP4Z1 is a human cytochrome P450 enzyme involved in breast cancer progression and prognosis, but its functional role in these processes is not understood. In order to gain more insight into CYP4Z1's properties it was recombinantly expressed in a host animal that does not have an endogenous homologue. METHODS: We generated a transgenic mouse model that specifically expresses human CYP4Z1 in breast tissue under the control of the whey acidic protein promoter. Complementary experiments were done using cell lines derived from human breast cell. RESULTS: Induction of CYP4Z1 expression led to reduction of body weight, activity, and birth rates. Histological analysis revealed no evidence for tumor formation. However, a strong increase in estrogen receptor alpha was observed by immunohistochemistry; weaker but significantly increased immunoreactivity was also detected for collagen I and fibronectin. Overexpression of CYP4Z1 in the human breast cancer cell line MCF7 also led to increased ERα expression. Moreover, increased expression of both CYP4Z1 and ERα was observed in MCF-10A normal breast cells upon cocultivation with MCF-7 cells (with or without overexpression of CYP4Z1). CONCLUSION: These data suggest that CYP4Z1 facilitates breast cancer development by induction of ERα expression via an as yet undefined mechanism.

Overexpression of angiogenic factors and matrix metalloproteinases in the saliva of oral squamous cell carcinoma patients: potential non-invasive diagnostic and therapeutic biomarkers.

BACKGROUNDS: Salivary biomarkers hold huge potential for the non-invasive diagnosis of oral squamous cell carcinoma. Angiogenic factors and matrix-metalloproteinases (MMPs) are highly expressed in OSCC tissue, but their expression patterns in the saliva are unknown. This study aimed to analyze the levels of angiogenic factors and MMPs in tumor tissue and saliva of OSCC patients. METHODS: OSCC-tissue, adjacent normal tissue (ANT), saliva from OSCC patients, and healthy controls were obtained. The expression patterns of angiogenic factors and MMPs were analyzed by immunohistochemistry, protein chip array, and RT-qPCR. RESULTS: Results showed higher expression of ANG, ANG-2, HGF, PIGF, VEGF, MMP-1, MMP-2, MMP-3, MMP-8, MMP-9, MMP-10, MMP-13, TIMP-1, and TIMP-2 in OSCC-tissues compared to the ANT. Among the overexpressed markers in OSCC-tissues, HGF, VEGF, PIGF, PDGF-BB, MMP-1, MMP-3, MMP-8, MMP-9, MMP-10, MMP-13, and TIMP-2 were significantly upregulated in the saliva of OSCC patients compared to healthy controls. CONCLUSIONS: The levels of HGF, VEGF, PIGF, MMP-1, MMP-3, MMP-8, MMP-9, MMP-10, MMP-13, and TIMP-2 were upregulated both in OSCC tissue and saliva of OSCC patients. Bioinformatic analysis revealed the correlation of these factors with patient survival and cancer functional states in head and neck cancer, indicating these factors as possible saliva-based non-invasive diagnostic/prognostic markers and therapeutic targets of OSCC.

Notoginsenoside R1 Promotes Migration, Adhesin, Spreading, and Osteogenic Differentiation of Human Adipose Tissue-Derived Mesenchymal Stromal Cells.

Cellular activities, such as attachment, spreading, proliferation, migration, and differentiation are indispensable for the success of bone tissue engineering. Mesenchymal stromal cells (MSCs) are the key precursor cells to regenerate bone. Bioactive compounds from natural products had shown bone regenerative potential. Notoginsenoside R1 (NGR1) is a primary bioactive natural compound that regulates various biological activities, including cardiovascular protection, neuro-protection, and anti-cancer effects. However, the effect of NGR1 on migration, adhesion, spreading, and osteogenic differentiation of MSCs required for bone tissue engineering application has not been tested properly. In this study, we aimed to analyze the effect of NGR1 on the cellular activities of MSCs. Since human adipose-derived stromal cells (hASCs) are commonly used MSCs for bone tissue engineering, we used hASCs as a model of MSCs. The optimal concentration of 0.05 µg/mL NGR1 was biocompatible and promoted migration and osteogenic differentiation of hASCs. Pro-angiogenic factor VEGF expression was upregulated in NGR1-treated hASCs. NGR1 enhanced the adhesion and spreading of hASCs on the bio-inert glass surface. NGR1 robustly promoted hASCs adhesion and survival in 3D-printed TCP scaffold both in vitro and in vivo. NGR1 mitigated LPS-induced expression of inflammatory markers IL-1ß, IL-6, and TNF-α in hASCs as well as inhibited the RANKL/OPG expression ratio. In conclusion, the biocompatible NGR1 promoted the migration, adhesion, spreading, osteogenic differentiation, and anti-inflammatory properties of hASCs.

The impact of Er:YAG laser combined with fluoride treatment on the supragingival plaque microbiome in children with multiple caries: a dynamic study.

BACKGROUND: As a minimally invasive tool for caries prevention tool, the pulsed erbium:yttrium-aluminum-garnet (Er:YAG) laser is being used in a large number of studies. Microorganisms are extremely vital in the occurrence and development of dental caries. However, the impact of Er:YAG laser irradiation combined with fluoride on the dynamic microbial changes that occur in dental plaques is still uncertain. In this study, we examined the effect of an Er:YAG laser combined with fluorine on supragingival microbial composition and diversity in children with multiple caries. METHODS: In this study, dental plaque samples (n = 48) were collected from 12 children with over 8 filled teeth. Supragingival plaques from left mandibular molars before (CB) and after fluoride treatment (CA) and right mandibular molars before (EB) and after fluoride+Er:YAG laser treatment (EA) were collected from each patient. In CB and EB groups, the samples were collected just before the treatments. In CA and EA groups, the samples were collected 1 month after treatments. Then, all specimens were subjected to 16S rRNA high-throughput sequencing to investigate the changes in microbial composition and diversity in mandibular molar supragingival plaques before and after fluoride or fluoride+Er:YAG laser treatment. RESULTS: The dental plaque microbial diversity was higher in the EA group than in the EB group (baseline levels), and the microbial composition changed in EA group compared with EB group (P < 0.05). The levels of microorganisms associated with caries occurrence, including Proteobacteria, Fusobacteria, and Bacteroidetes, declined, while the levels of Faecacterium, Fastidiosipila, Vibrio, and Shewanella increased in EA group compared with EB group. The declines in Firmicutes, Streptococcus, Fusobacterium, and Veillonella levels were significantly lower in the EA group than in the CA group. CONCLUSION: The combined application of the Er:YAG laser and fluoride may be more effective than using fluoride alone in reducing the proportion of cariogenic bacteria, increasing the diversity of plaque microorganisms, and further promoting the microecological balance.

K-Carrageenan Stimulates Pre-Osteoblast Proliferation and Osteogenic Differentiation: A Potential Factor for the Promotion of Bone Regeneration?

Current cell-based bone tissue regeneration strategies cannot cover large bone defects. K-carrageenan is a highly hydrophilic and biocompatible seaweed-derived sulfated polysaccharide, that has been proposed as a promising candidate for tissue engineering applications. Whether κ-carrageenan can be used to enhance bone regeneration is still unclear. In this study, we aimed to investigate whether κ-carrageenan has osteogenic potential by testing its effect on pre-osteoblast proliferation and osteogenic differentiation in vitro. Treatment with κ-carrageenan (0.5 and 2 mg/mL) increased both MC3T3-E1 pre-osteoblast adhesion and spreading at 1 h. K-carrageenan (0.125-2 mg/mL) dose-dependently increased pre-osteoblast proliferation and metabolic activity, with a maximum effect at 2 mg/mL at day three. K-carrageenan (0.5 and 2 mg/mL) increased osteogenic differentiation, as shown by enhanced alkaline phosphatase activity (1.8-fold increase at 2 mg/mL) at day four, and matrix mineralization (6.2-fold increase at 2 mg/mL) at day 21. K-carrageenan enhanced osteogenic gene expression (Opn, Dmp1, and Mepe) at day 14 and 21. In conclusion, κ-carrageenan promoted MC3T3-E1 pre-osteoblast adhesion and spreading, metabolic activity, proliferation, and osteogenic differentiation, suggesting that κ-carrageenan is a potential osteogenic inductive factor for clinical application to enhance bone regeneration.

Osteocyte-Mediated Translation of Mechanical Stimuli to Cellular Signaling and Its Role in Bone and Non-bone-Related Clinical Complications.

PURPOSE OF REVIEW: Osteocytes comprise > 95% of the cellular component in bone tissue and produce a wide range of cytokines and cellular signaling molecules in response to mechanical stimuli. In this review, we aimed to summarize the molecular mechanisms involved in the osteocyte-mediated translation of mechanical stimuli to cellular signaling, and discuss their role in skeletal (bone) diseases and extra-skeletal (non-bone) clinical complications. RECENT FINDINGS: Two decades before, osteocytes were assumed as a dormant cells buried in bone matrix. In recent years, emerging evidences have shown that osteocytes are pivotal not only for bone homeostasis but also for vital organ functions such as muscle, kidney, and heart. Osteocyte mechanotransduction regulates osteoblast and osteoclast function and maintains bone homeostasis. Mechanical stimuli modulate the release of osteocyte-derived cytokines, signaling molecules, and extracellular cellular vesicles that regulate not only the surrounding bone cell function and bone homeostasis but also the distant organ function in a paracrine and endocrine fashion. Mechanical loading and unloading modulate the osteocytic release of NO, PGE2, and ATPs that regulates multiple cellular signaling such as Wnt/ß-catenin, RANKL/OPG, BMPs, PTH, IGF1, VEGF, sclerostin, and others. Therefore, the in-depth study of the molecular mechanism of osteocyte mechanotransduction could unravel therapeutic targets for various bone and non-bone-related clinical complications such as osteoporosis, sarcopenia, and cancer metastasis to bone.

Cytochrome P450 expression patterns in human osteoblasts during osteogenic differentiation with or without TNFα treatment.

BACKGROUND: Recently the expression patterns of several cytochrome P450 (CYP) genes in different human osteoblast models were reported. However, the various expression patterns of CYPs in human osteoblasts during different stages of osteogenic differentiation have not been investigated and the effect of inflammatory cytokines on CYPs expression in osteoblasts is unknown. METHODS: The expression levels of nine different CYP genes in the human osteoblast cell line MG63 and in primary human osteoblasts (HOB) during osteogenic differentiation with or without treatment with tumor necrosis factor-α (TNFα) were analyzed by quantitative real-time PCR. RESULTS: The expression levels of most CYPs under study show a significant time dependence during osteogenic differentiation. Overall, more highly significant CYP expression level changes occur in HOB than in MG63 cells. Treatment with TNFα causes a variety of CYP expression level changes in both HOB and MG63 cells. CONCLUSIONS: Our findings indicate that TNFα treatment reduces steroid hormone production in MG63 cells (but not in HOB) at the level of lanosterol-demethylation during cholesterol biosynthesis. By contrast, TNFα treatment of HOB cells (but not in MG63) leads to the upregulation of several key enzymes involved in the biosynthesis of sex steroids, which is proposed to lead to higher levels of estrogen production. These data also suggest that at least with respect to the topic of this study the cell line MG63 is not a good representative for osteoblasts and that it is preferential to use primary osteoblasts instead.

Pro-inflammatory Cytokines and Osteocytes.

PURPOSE OF REVIEW: An elevated level of pro-inflammatory cytokines in inflammatory conditions causes bone loss and disrupts vital organ function. Osteocytes comprise > 95% of the cellular component in bone tissue, produce a range of cytokines and signaling molecules, and influence bone and other organ function. In this review, we hypothesized that an elevated level of pro-inflammatory cytokines in inflammatory conditions affects osteocyte survival and function thereby possibly amplifying inflammation, and causing bone loss and non-bone clinical complications. RECENT FINDINGS: Several studies have reported that the elevated level of pro-inflammatory cytokines in inflammatory conditions alters osteocyte mechanosensitivity, causes osteocyte apoptosis, and modulates osteocyte-derived production of various inflammatory cytokines and signaling molecules. Cytokines and signaling molecules released from osteocytes affect surrounding bone cells and distant organ function in a paracrine and endocrine fashion. Inflammatory diseases including diabetes, chronic kidney disease, rheumatoid arthritis, and periodontitis affect osteocyte survival and function, and upregulate osteocyte-derived expression of sclerostin, RANKL, TNFα, FGF23, DKK1, and other signaling molecules.

Cellular hypoxia promotes osteogenic differentiation of mesenchymal stem cells and bone defect healing via STAT3 signaling.

BACKGROUND: Hypoxia in the vicinity of bone defects triggers the osteogenic differentiation of precursor cells and promotes healing. The activation of STAT3 signaling in mesenchymal stem cells (MSCs) has similarly been reported to mediate bone regeneration. However, the interaction between hypoxia and STAT3 signaling in the osteogenic differentiation of precursor cells during bone defect healing is still unknown. METHODS: In this study, we assessed the impact of different durations of CoCl2-induced cellular hypoxia on the osteogenic differentiation of MSCs. Role of STAT3 signaling on hypoxia induced osteogenic differentiation was analyzed both in vitro and in vivo. The interaction between cellular hypoxia and STAT3 signaling in vivo was investigated in a mouse femoral bone defect model. RESULTS: The peak osteogenic differentiation and expression of vascular endothelial growth factor (VEGF) occurred after 3 days of hypoxia. Inhibiting STAT3 reversed this effect. Hypoxia enhanced the expression of hypoxia-inducible factor 1-alpha (HIF-1α) and STAT3 phosphorylation in MSCs. Histology and µ-CT results showed that CoCl2 treatment enhanced bone defect healing. Inhibiting STAT3 reduced this effect. Immunohistochemistry results showed that CoCl2 treatment enhanced Hif-1α, ALP and pSTAT3 expression in cells present in the bone defect area and that inhibiting STAT3 reduced this effect. CONCLUSIONS: The in vitro study revealed that the duration of hypoxia is crucial for osteogenic differentiation of precursor cells. The results from both the in vitro and in vivo studies show the role of STAT3 signaling in hypoxia-induced osteogenic differentiation of precursor cells and bone defect healing.

Three years of follow-up of otodental syndrome in 3-year-old Chinese boy: a rare case report.

BACKGROUND: Otodental syndrome is an exceptionally rare autosomal dominant condition characterized by a delayed eruption of posterior teeth, globodontia, lisping, and sensorineural hearing loss. In this case report, we reported a 3-year-old Chinese boy with the otodental syndrome. CASE PRESENTATION: A 3-year-old Chinese boy was referred to our hospital with complaint of no eruption of primary canines and molars. Three years follow-up showed lately erupted bulbous primary canines with hypoplastic enamel spot, globe-shaped primary molars and sensorineural hearing loss at 4 and a half-year-old age. We diagnosed otodental syndrome in the patient's mother with hearing loss at 16-year-old age. Gene sequencing and analysis of deafness-related genes GJB2, GJB3, SLC26A4, and mtDNA did not reveal any mutation or SNPs in the patient and his mother. CONCLUSIONS: This case report highlights the importance of detailed medical, dental, and family history examination, as well as multi-disciplinary teamwork for diagnosis and treatment of otodental syndrome.

Inhibition of JAK2/STAT3 signaling suppresses bone marrow stromal cells proliferation and osteogenic differentiation, and impairs bone defect healing.

Mesenchymal stem cells (MSCs) undergo osteogenic differentiation during bone defect healing. However, the role of JAK2/STAT3 in the osteogenic differentiation of MSCs and bone defect healing is still not fully understood. In this study, we aimed to analyze the effect of AG490, a JAK2-specific inhibitor, on MSCs proliferation and osteogenic differentiation as well as in bone defect healing. We used AG490 to inhibit the JAK2/STAT3 signaling in a mice bone marrow stromal cells (BMSCs) culture. AG490 inhibited BMSCs proliferation and osteogenic differentiation markers, i.e. Col1α, Alp and Ocn expression in mRNA and protein levels. Inhibition of JAK2 reduced ALP activity and matrix mineralization in BMSCs culture. Inhibition of JAK2 reduced phosphorylation of STAT3, AKT, P38, and JNK phosphorylation. Immunohistochemistry showed high numbers of pJAK2, pSTAT3 and ALP positive cells and AG490 reduced this effect in vivo. Histology and µ-computed tomography (CT) data showed that AG490 treatment inhibits bone regeneration and bone defect healing. Our results clearly showed the inhibitory effect of AG490 on proliferation and osteogenic differentiation of BMSCs, bone regeneration and bone defect healing. Moreover, AG490 inhibited phosphorylation of STAT3, P38, JNK and AKT. This suggests the possible role of JAK2/STAT3 signaling in hypoxia-induced osteogenic differentiation of MSCs and bone defect healing.

CoCl2 , a mimic of hypoxia, enhances bone marrow mesenchymal stem cells migration and osteogenic differentiation via STAT3 signaling pathway.

Mesenchymal stem cells homing and migration is a crucial step during bone fracture healing. Hypoxic environment in fracture site induces bone marrow mesenchymal stem cells (BMSCs) migration, but its mechanism remains unclear. Our previous study and studies by other groups have reported the involvement of signal transducer and activator of transcription 3 (STAT3) pathway in cell migration. However, the role of STAT3 pathway in hypoxia-induced cell migration is still unknown. In this study, we investigated the role of STAT3 signaling in hypoxia-induced BMSCs migration and osteogenic differentiation. BMSCs isolated from C57BL/6 male mice were cultured in the presence of cobalt chloride (CoCl2 ) to simulate intracellular hypoxia. Hypoxia enhanced BMSCs migration, and upregulated cell migration related gene expression, that is, metalloproteinase (MMP) 7, MMP9, and C-X-C motif chemokine receptor 4. Hypoxia enhanced the phosphorylation of STAT3, and cell migration related proteins: c-jun n-terminal kinase (JNK), focal of adhesion kinase (FAK), extracellular regulated protein kinases, and protein kinase B 1/2 (ERK1/2). Moreover, hypoxia enhanced expression of osteogenic differentiation marker. Inhibition of STAT3 suppressed the hypoxia-induced BMSCs migration, cell migration related signaling molecules phosphorylation, and osteogenic differentiation related gene expression. In conclusion, our result indicates that hypoxia-induced BMSCs migration and osteogenic differentiation is via STAT3 phosphorylation and involves the cooperative activity of the JNK, FAK, and MMP9 signaling pathways.

A case report of hemolytic streptococcal gangrene in the danger triangle of the face with thrombocytopenia and hepatitis.

BACKGROUND: Hemolytic streptococcus gangrene is a life threatening invasive bacterial infection. Hemolytic streptococcus gangrene in the danger triangle of the face is too lethal to operate. A case of the confirmed hemolytic streptococcus gangrene in the danger triangle of the face caused by Group A beta-hemolytic streptococcus (GAS) in 20-months old boy is presented to draw attention of clinicians to this uncommon but frequently fatal infection. CASE PRESENTATION: Previously healthy 20 months old boy suddenly developed paranasal gangrene on the left side of the danger triangle of the face, followed by rapidly progressive thrombocytopenia and hepatitis. The clinical features, liver function, and hematological and serological parameters resembled to a description of streptococcal toxic shock syndrome (STSS). Aggressive antibiotics, substitutional and supportive therapy were conducted without surgical debridement of facial tissues. Prompt diagnosis and aggressive timely treatment completely cured the disease in 28 days. CONCLUSIONS: The present case report demonstrates prompt diagnosis and timely treatment as a strategy to cure the fatal hemolytic streptococcus gangrene located in too risky body part to operate.

Comparison of cytochrome P450 expression in four different human osteoblast models.

Cytochromes P450 (CYPs) are important for bone homeostasis, but only limited information is available on their expression in human bone cells. We analyzed the expression levels of eight CYPs in osteoblasts cultured in human bone pieces, in osteoblasts differentiated from human periosteum mesenchymal stem cells, in primary human osteoblasts and in the human osteoblast cell line MG63, respectively. Our results confirm previous reports about the presence of CYP11A1, CYP17A1, CYP24A1 and CYP27B1, while demonstrating expression of CYP2E1, CYP26A1, CYP39A1 and CYP51A1 for the first time. However, expression patterns in the four models were remarkably different from each other.