TPG-functionalized PLGA/PCL nanofiber membrane facilitates periodontal tissue regeneration by modulating macrophages polarization via suppressing PI3K/AKT and NF-κB signaling pathways.

Traditional fibrous membranes employed in guided tissue regeneration (GTR) in the treatment of periodontitis have limitations of bioactive and immunomodulatory properties. We fabricated a novel nTPG/PLGA/PCL fibrous membrane by electrospinning which exhibit excellent hydrophilicity, mechanical properties and biocompatibility. In addition, we investigated its regulatory effect on polarization of macrophages and facilitating the regeneration of periodontal tissue both in vivo and in vitro. These findings showed the 0.5%TPG/PLGA/PCL may inhibit the polarization of RAW 264.7 into M1 phenotype by suppressing the PI3K/AKT and NF-κB signaling pathways. Furthermore, it directly up-regulated the expression of cementoblastic differentiation markers (CEMP-1 and CAP) in periodontal ligament stem cells (hPDLSCs), and indirectly up-regulated the expression of cementoblastic (CEMP-1 and CAP) and osteoblastic (ALP, RUNX2, COL-1, and OCN) differentiation markers by inhibiting the polarization of M1 macrophage. Upon implantation into a periodontal bone defect rats model, histological assessment revealed that the 0.5%TPG/PLGA/PCL membrane could regenerate oriented collagen fibers and structurally intact epithelium. Micro-CT (BV/TV) and the expression of immunohistochemical markers (OCN, RUNX-2, COL-1, and BMP-2) ultimately exhibited satisfactory regeneration of alveolar bone, periodontal ligament. Overall, 0.5%TPG/PLGA/PCL did not only directly promote osteogenic effects on hPDLSCs, but also indirectly facilitated cementoblastic and osteogenic differentiation through its immunomodulatory effects on macrophages. These findings provide a novel perspective for the development of materials for periodontal tissue regeneration.

Inflammasome-targeting natural compounds in inflammatory bowel disease: Mechanisms and therapeutic potential.

Inflammatory bowel disease (IBD), mainly including Crohn's disease and ulcerative colitis, seriously affects human health and causes substantial social and economic burden. The pathogenesis of IBD is still not fully elucidated, whereas recent studies have demonstrated that its development is associated with the dysfunction of intestinal immune system. Accumulating evidence have proven that inflammasomes such as NLRP3 and NLRP6 play a prominent role in the pathogenesis of IBD. Thus, regulating the activation of inflammasomes have been considered to be a promising strategy in IBD treatment. A number of recent studies have provided evidence that blocking inflammasome related cytokine IL-1ß can benefit a group of IBD patients with overactivation of NLRP3 inflammasome. However, therapies for targeting inflammasomes with high efficacy and safety are rare. Traditional medical practice provides numerous medical compounds that may have a role in treatment of various human diseases including IBD. Recent studies demonstrated that numerous medicinal herb derived compounds can efficiently prevent colon inflammation in animal models by targeting inflammasomes. Herein, we summarize the main findings of these studies focusing on the effects of traditional medicine derived compounds on colitis treatment and the underlying mechanisms in regulating the inflammasomes. On this basis, we provide a perspective for future studies regarding strategies to improve the efficacy, specificity and safety of available herbal compounds, and to discover new compounds using the emerging new technologies, which will improve our understanding about the roles and mechanisms of herbal compounds in the regulation of inflammasomes and treatment of IBD.

Expression of autophagy and apoptosis-related factors in the periodontal tissue of experimental diabetic rats: a histomorphometric, microtomographic and immunohistochemical study.

OBJECTIVE: This study aimed to investigate the expression of autophagy-related factors microtubule-associated protein l light chain 3 (LC3) and the apoptosis-related factors BCL2-associated X protein (Bax) and B cell lymphoma-2 (Bcl-2) in the periodontal tissue of experimental diabetic rats. These data were used to explore the potential mechanism in diabetes-induced periodontal tissue lesions. METHODS: A total of 32 Sprague Dawley (SD) rats were randomly assigned into diabetes (group D, n = 16) and control groups (group N, n = 16). The diabetic group was induced by intraperitoneal injection of 1% streptozotocin (STZ, 60 mg/kg) and the control group was injected with citrate buffer (0.1mol/L). Rats were sacrificed after 4 and 8 weeks of feeding and collected as D1, N1 groups and D2, N2 groups, and the maxilla were retained for analysis. The changes in periodontal tissue structure were observed by hematoxylin-eosin (HE) staining. The expression and distribution of LC3, Bax and Bcl-2 in the periodontium of the rats was detected by immunohistochemical (SP) staining. RESULTS: Diabetic rats showed several changes compared to control animals including sparse alveolar bone trabecular structure, loss of the lamina dura and absorption of the local alveolar bone. The positive expression level of LC3 in the gingival epithelial, periodontal ligament and alveolar bone of group D1 was significantly higher than in the N1, N2 and D2 groups (P < 0.05). The level of Bax expression in the group D2 rats was significantly higher than those in the N1, N2 and D1 groups (P < 0.05), while the positive degree of Bcl-2 was significantly lower than those of other groups (P < 0.001). LC3 was negatively correlated with Bax and was irrelevant with Bcl-2; Bcl-2 was not correlated with Bax. CONCLUSIONS: The expression of LC3, Bax and Bcl-2 changes in the periodontal tissue of diabetic rats may indicate that autophagy and apoptotic are involved in the process of periodontal tissue damage in diabetic rats. These changes may be one of the mechanisms of periodontal tissue lesions.

The inhibitory effect of the deubiquitinase cylindromatosis (CYLD) on inflammatory responses in human gingival fibroblasts.

OBJECTIVE: Experiments were performed to evaluate CYLD expression in human gingival tissue samples and to examine the effects of CYLD on inflammatory responses in lipopolysaccharide (LPS)- or TNF-α-stimulated human gingival fibroblasts (HGFs). METHODS: Immunohistochemistry for CYLD and p65 expression was performed with healthy and inflamed gingival tissue samples. siRNA was used to knock down the expression of CYLD in HGFs. Upon LPS or TNF-α stimulation, NF-κB activation was detected in control and CYLD-knockdown HGFs. RT-PCR was applied to determine gene expression. Western blot analyses were employed to assess protein expression. Immunofluorescence staining was carried out to evaluate the nuclear translocation of p65. RESULTS: Immunohistochemical staining showed the expression of CYLD in human gingival tissues. In addition, CYLD protein expression was reduced in inflamed gingival tissue samples compared with healthy tissue samples. CYLD knockdown greatly enhanced the mRNA expression of proinflammatory cytokines in LPS- or TNF-α-stimulated HGFs. Furthermore, knocking down CYLD expression increased LPS-stimulated NF-κB activation in HGFs. Unexpectedly, CYLD knockdown did not affect TNF-α-induced NF-κB activation. CONCLUSIONS: Our results suggest that CYLD participates in periodontal inflammatory responses by negatively regulating LPS-induced NF-κB signalling.

[Clinical evaluation of Er:YAG laser in the treatment of grade â ¡ periodontitis with bifurcation lesions].

PURPOSE: To evaluate the clinical efficacy of erbium-doped yttrium aluminium garnet (Er: YAG) laser in the treatment of degree II bifurcation periodontitis. METHODS: Thirty patients(60 teeth) with grade II bifurcation lesions of chronic periodontitis were enrolled in this study. One week after supergingival scaling with ultrasound, the patients were randomly divided into experimental group: subgingival scaling with ultrasound and hand instruments + Er: YAG laser irradiation in periodontal pocket; control group: the contralateral homonymous teeth were treated with subgingival scaling with ultrasound and hand instruments alone. The changes of gingival index(GI), pocket depth(PD), horizontal probing depth (HPD) and attachment loss(AL) were compared between the two groups 12 and 20 weeks after treatment. SPSS 20.0 software package was used for statistical analysis. RESULTS: Periodontal clinical indexes(GI, PD, HPD, AL) of the experimental group and control group were significantly reduced compared with baseline at 12 and 20 weeks after treatment(P<0.05). At 12 and 20 weeks after treatment, PD in the experimental group was (4.03±0.48) mm and (3.43±0.45) mm, (4.82±0.55) mm and (4.27±0.36) mm in the control group, respectively. The reduction of PD in the experimental group was significantly greater than that in the control group (P<0.05). There was no significant difference in HPD between the two groups at 12 weeks after treatment. Twenty weeks after operation, HPD in the experimental group was found to be (3.01±0.34) mm and (3.78±0.29) mm in the control group. The decrease of HPD in the experimental group was significantly greater than that in the control group (P<0.05). GI and AL of the experimental group at 12 and 20 weeks were lower than those of the control group, but the difference was not statistically significant. CONCLUSIONS: Er: YAG laser is safe and effective in the treatment of chronic periodontitis patients with grade II root bifurcation lesions with significant clinical value.

AGEs induces apoptosis and autophagy via reactive oxygen species in human periodontal ligament cells.

The apoptosis of human periodontal ligament cells (HPDLCs) may be an important factor of the negative effect of advanced glycation end products (AGEs) on the periodontal tissue of diabetic patients. However, the pathways or potential effects of apoptosis in AGEs-treated HPDLCs have not been fully elucidated. Autophagy is closely related to apoptosis. Herein, we investigated the potential mechanism of apoptosis and autophagy in HPDLCs treated with AGEs via an in vitro model. We found that AGEs-treated HPDLCs showed a time- and concentration-dependent reduction in the cell survival rate. The mitochondrial-dependent apoptosis was induced in AGEs-treated HPDLCs, as confirmed by the mitochondrial membrane potential depolarization, decreased Bcl-2 expression, increased Bax expression, and increased caspase-3 and PARP cleavage. Autophagy was also induced in AGEs-treated HPDLCs, as indicated by the conversion of LC3-II/LC3-I and the presence of autophagosomes. Interestingly, our study results suggested that apoptosis and autophagy were related to reactive oxygen species (ROS) production. In addition, AGEs-induced autophagy acted as a latent factor in decreasing the generation of ROS in HPDLCs and protecting against the AGEs-induced apoptosis. In summary, our study shows that ROS are essential in AGEs-induced HPDLCs apoptosis and autophagy, which may be a molecular mechanism for the repairment of ROS-induced damage in HPDLCs treated with AGEs to promote cell survival. The present study might provide new insights into the therapeutic targeting of HPDLCs autophagy, which could be an additional strategy for periodontitis in patients with diabetes mellitus.

M1 macrophages regulate TLR4/AP1 via paracrine to promote alveolar bone destruction in periodontitis.

OBJECTIVE: Macrophages could be fully polarized and acquire specific phenotype like M1, which considered to be essential for the alveolar bone destruction during the development of periodontitis. However, the molecular mechanisms underlying the effects of M1 macrophages on the alveolar bone destruction are still not clear yet. METHODS: Mouse periodontitis model was established to determine the involvement of M1 macrophages in the pathogenic process. Condition medium of the M1 macrophages (M1-CM) was incubated with pre-osteoblasts to evaluate its effects on the osteoblastogenesis. Cells after treatment with CM were used for RNA-sequencing, quantitative PCR, Western blotting, and immunofluorescence staining to figure out pathways involved in the inhibition of osteoblastogenesis. RESULTS: Increased infiltration of M1 macrophages was associated with alveolar bone destruction in periodontitis. M1-CM markedly suppressed the generation of osteoblasts as evidenced by decreased expressions of Runx2 and Ocn, as well as reduced activity of ALP. Interestingly, RNA-sequencing indicated the activation of TLR4/AP1 signaling pathway in pre-osteoblasts treated with CM. Inhibition of TLR4 reduced the translocation of AP1 and rescued the osteoblastogenesis reduced by M1-CM. CONCLUSION: M1 macrophages induce TLR4/AP1 signaling of pre-osteoblasts to inhibit the osteoblastogenesis via paracrine, at least partially contributing to alveolar bone destruction in periodontitis.

[Correlation between hyperglycemia levels and periodontitis in 545 officeholders in Nantong city].

PURPOSE: To identify the relationship between hyperglycemia levels and periodontitis by investigating the levels of hyperglycemia and periodontal conditions of officeholders in Nantong city. METHODS: From January 2013 to January 2014, 545 officeholders were randomly selected in Nantong City who underwent physical examination and divided into 2 groups: young of middle-aged adults(≤60 years) and old adults (>60 years). The data was analyzed with Chi-square test and multi-factors logistic regression by using SPSS 16.0 software package. RESULTS: There was a significant correlation between blood glucose levels and periodontitis. Multi-factor Logistic regression analysis showed that in the whole population, smoking, age, blood glucose levels were significantly correlated with the degree of periodontitis (P<0.05). Smoking and low level of education were associated with periodontitis in young and middle-aged adults. In old people, blood glucose level more than 7.0 mmol/L and smoking were the risk factors for periodontitis. CONCLUSIONS: Hyperglycemia level is risk factor for periodontitis, which has an effect mainly on old adults.