Er:YAG Laser Alleviates Inflammaging in Diabetes-Associated Periodontitis via Activation CTBP1-AS2/miR-155/SIRT1 Axis.

Periodontitis is a significant health concern for individuals with diabetes mellitus (DM), characterized by inflammation and periodontium loss. Hyperglycaemia in DM exacerbates susceptibility to periodontitis by inducing inflammaging in the host immune system. The use of erbium-doped yttrium-aluminum-garnet laser (ErL) in periodontitis treatment has gained attention, but its impact on diabetic-associated periodontitis (DP) and underlying mechanisms remain unclear. In this study, we simulated DP by exposing human periodontal ligament fibroblasts (PDLFs) to advanced glycation end products (AGEs) and lipopolysaccharides from P. gingivalis (Pg-LPS). Subsequently, we evaluated the impact of ErL on the cells' wound healing and assessed their inflammaging markers. ErL treatment promoted wound healing and suppressed inflammaging activities, including cell senescence, IL-6 secretion, and p65 phosphorylation. Moreover, the laser-targeted cells were observed to have upregulated expression of CTBP1-AS2, which, when overexpressed, enhanced wound healing ability and repressed inflammaging. Moreover, bioinformatic analysis revealed that CTBP1-AS2 acted as a sponge for miR155 and upregulated SIRT1. In conclusion, ErL demonstrated the ability to improve wound healing and mitigate inflammaging in diabetic periodontal tissue through the CTBP1-AS2/miR-155/SIRT1 axis. Targeting this axis could represent a promising therapeutic approach for preventing periodontitis in individuals with DM.

Galectin-7 promotes proliferation and wound healing capacities in periodontal ligament fibroblasts by activating ERK signaling.

Periodontitis is a progressive inflammation condition and a primary cause of tooth loss in adults. As one of the abundant cell types in the periodontium, periodontal ligament fibroblasts (PDLFs) play an integral role in the maintenance and regeneration of periodontal tissue. Our previous work has shown that the application of Er:YAG laser increased the cell proliferation and migratory capacity of PDLFs via induction of galectin-7. In the present study, we aimed to evaluate if the forced expression of galectin-7 directly affected the cellular phenotypes of PDLFs. Our results showed that the cell proliferation, transwell migration, invasion, and wound healing capacities were all upregulated in PDLFs with the ectopic expression of galectin-7. These results suggest that therapeutic approaches to enhance the expression of galectin-7 in periodontium may accelerate tissue regeneration by recruiting more PDLFs to the injured site.

Er:YAG laser promotes proliferation and wound healing capacity of human periodontal ligament fibroblasts through Galectin-7 induction.

BACKGROUND/PURPOSE: Among various dental lasers, the erbium-doped yttrium-aluminum-garnet (Er:YAG) laser has great potential for periodontal treatment including soft and hard tissue ablation with minimal thermal side effects under suitable energy densities and it has multiple effects on tissues for wound-healing benefits. In the present study, we sought to reveal the molecular mechanism underlying the impact of Er:YAG laser on PDL fibroblasts. METHODS: Cells were irradiated by a Er:YAG laser with various energy densities (3.6-6.3 J/cm2). MTT assay was used for cell proliferation, and the transwell system was employed for migration and invasion abilities. The wound healing capacity was evaluated by a scratch assay. After confirming these effects, qRT-PCR and western blotting analysis was applied to identify the differentially galectin-7 expression in the irradiated cells. Knockdown experiments were conducted to reveal the functional role of galectin-7 in the modulation of Er:YAG laser-mediated effects. RESULTS: 4.2 J/cm2 was the lowest energy density to induce the optimal cell proliferation, migration and invasion abilities. In the group of upregulated genes, galectin-7 was selected for further examination and its elevation after Er:YAG laser treatment was validated by RT-PCR and Western blot. We demonstrated that silence of galectin-7 abrogated the effects of Er:YAG laser on cell proliferation, migration ad invasion, suggesting the Er:YAG laser promoted these effects through induction of galectin-7. CONCLUSION: These findings indicated that Er:YAG laser may accelerate the regeneration process in periodontal tissues through enhancement of their proliferative and mobile activities. Additionally, the significance of galectin-7 in the Er:YAG laser-elicited benefits was demonstrated.

Recommendations for treating stage I-III periodontitis in the Taiwanese population: A consensus report from the Taiwan Academy of Periodontology.

BACKGROUND/PURPOSE: Based on the fundamental of the S3-level clinical practice guideline (CPG) for treating stage I-III periodontitis developed by the European Federation of Periodontology (EFP), this consensus report aimed to develop treatment recommendations for treating periodontitis in the Taiwanese population. METHODS: The report was constructed by experts from the Taiwan Academy of Periodontology. The following topics were reviewed: (a) the prevalence of periodontitis in Asia and current status of treatment in Taiwan; (b) specific anatomical considerations for treating periodontitis in Asians; (d) educational and preventive interventions and supragingival plaque control; (d) subgingival instrumentation and adjunctive treatment; (e) surgical periodontal therapy; and (f) maintenance and supportive periodontal care. Recommendations were made according to the evidences from the EFP CPG, the published literature and clinical studies in Asians, and the expert opinions. RESULTS: The treatment recommendations for the Taiwanese population were generally in parallel with the EFP CPG, and extra cautions during treatment and maintenance phases were advised due to the anatomical variations, such as shorter root trunk, higher prevalence of supernumerary distolingual root and lingual bony concavity in mandibular posteriors, and thinner anterior labial plate, of the Asian population. CONCLUSION: The EFP CPG could be adopted for treating periodontitis and maintaining periodontal health of the Taiwanese population, and anatomical variations should be cautious when the treatment is delivered.

E3 ligase STUB1 attenuates stemness and tumorigenicity of oral carcinoma cells via transglutaminase 2 regulation.

BACKGROUND/PURPOSE: Oral cancer is amongst the most prevalent cancers worldwide with rising incidence. Various attempts have been made to elucidate its pathogenesis, and we sought to examine the function of a ubiquitin E3 ligase that was encoded by STUB1. METHODS: The mRNA expression of STUB1 in oral cancer samples and normal counterparts was determined by qRT-PCR. Numerous assays to assess the features of cancer cells, including self-renewal capacity, invasion and migration abilities were conducted following knockdown or overexpression of STUB1. RESULTS: The expression level of STUB1 was reduced in oral cancer, which was associated with a reduced relapse-free survival. Two oral cancer cell lines with low expression of STUB1 (SAS and HSC3) were chosen for the overexpression of STUB1. We showed that ectopic expression of STUB1 led to the downregulation of TGM2, a multifunctional protein that contributed to cancer progression in several cancers. Our results demonstrated that overexpression of STUB1 suppressed the cancer aggressiveness, while restoration of TGM2 reverted the effects. Last, we showed that STUB1 silencing resulted in enhanced cancer features. CONCLUSION: The abnormal downregulation of STUB1 may lessen its suppressive effect on TGM2, which induced the onset or exacerbated the progression of oral cancer. The therapeutic approach to enhance the expression of STUB1 could be a promising direction for cancer therapy.

Inhibition of HIF1A-AS1 impedes the arecoline-induced migration activity of human oral mucosal fibroblasts.

Long non-coding RNA hypoxia-inducible factor 1α-antisense RNA 1 (HIF1A-AS1) has been known to participate in various types of malignancies, but its role in the development of precancerous oral submucous fibrosis (OSF) has not been investigated. In the current study, we first observed the aberrant upregulation of HIF1A-AS1 in OSF tissues and fibrotic buccal mucosal fibroblasts (fBMFs) isolated from OSF specimens. Next, we demonstrated that administration of arecoline, a natural alkaloid that is found in areca nut, induced the elevation of HIF1A-AS1 in BMFs. This finding showed that the habit of areca nut chewing may lead to an increase of HIF1A-AS1 in oral mucosa. Moreover, we found that knockdown of HIF1A-AS1 hindered the arecoline-stimulated migration capacity in BMFs, suggesting HIF1A-AS1 was critical to the transdifferentiation of BMFs into myofibroblasts. Altogether, our results demonstrated that overexpression of HIF1A-AS1 in OSF tissues may result from the use of areca nut and lead to activation of BMFs, which contribute to the progression of OSF.

miR-200a inhibits proliferation rate in drug-induced gingival overgrowth through targeting ZEB2.

BACKGROUND/PURPOSE: Gingival overgrowth can occur as a result of poor oral hygiene or a side effect of taking certain medications, such as cyclosporine A (CsA). It has been shown that this immunosuppressant drug induces epithelial-to-mesenchymal transition (EMT) in the gingival epithelium but the associated molecular mechanism remains to be elucidated. METHODS: We first assessed the relative expression of microRNA-200a (miR-200a) in response to the CsA treatment using qRT-PCR. Next, luciferase reporter assay was applied to examine whether miR-200a was able to regulate ZEB2 and Western blot was utilized to measure the expression of ZEB2 in normal human gingival fibroblasts (HGFs). To confirm the significance of miR-200a and ZEB2 in the CsA-induced gingival overgrowth, miR-200a inhibitor and shRNA mediated knockdown of ZEB2 were used and cell proliferation in HGFs was assessed by MTT assay. RESULTS: The expression of miR-200a was dose-dependently downregulated following the CsA treatment. Luciferase reporter assay confirmed that ZEB2 was a direct downstream target regulated by miR-200a and ZEB2 was indeed increased after the administration of CsA. We demonstrated that knockdown of ZEB2 hampered the CsA-induced HGFs proliferation and the elevated cell proliferation due to inhibition of miR-200a was reversed by repression of ZEB2. CONCLUSION: Our results showed that insufficient miR-200a in HGFs caused by CsA administration may lead to gingival enlargement mediated by the upregulation of ZEB2. This finding supported that CsA-induced EMT contributed to the adverse effect of using CsA and miR-200a may serve as an upstream target to prevent the overgrowth of the gingiva.

miR-1246 as a therapeutic target in oral submucosa fibrosis pathogenesis.

BACKGROUND/PURPOSE: Oral submucous fibrosis (OSF) is a precancerous condition of oral cancer with a complex etiology. Our previous work has demonstrated that non-coding RNA miR-1246 contributes to the cancer stemness of oral cancer. In the current study, we sought to investigate the effect of the inhibition of miR-1246 on the oral fibrogenesis. METHODS: The expression levels of miR-1246 in OSF tissues and fibrotic buccal mucosal fibroblasts (fBMFs) were examined by qRT-PCR. Collagen gel contraction and migration assays were conducted to evaluate the myofibroblast activities. The relationship between miR-1246 and type I collagen was assessed and the protein expression of type I collagen was determined by Western blot. RESULTS: MiR-1246 expression was upregulated in both OSF specimen and fBMFs compared to the normal counterparts. Inhibition of miR-1246 successfully suppressed the myofibroblast activities, including collagen gel contractility and migration capacity. Moreover, the expression of miR-1246 was positively correlated with type I collagen and the expression of type I collagen was abrogated by repression of miR-1246. CONCLUSION: MiR-1246 is not only critical to the maintenance of oral stemness but also important to the activation of myofibroblasts. Our results showed that miR-1246 is positively associated with the type I collagen, which may be a downstream effector of miR-1246 and responsible for the fibrosis effect on fBMFs.

Butylidenephthalide abrogates the myofibroblasts activation and mesenchymal transdifferentiation in oral submucous fibrosis.

Oral submucous fibrosis (OSF) is a premalignant disorder in the oral cavity, and areca nut chewing habit has been implicated in the persistent activation of myofibroblasts and the subsequent fibrosis. Therefore, it is critical to ameliorate the excessive activities of myofibroblasts prior to the malignant transformation of OSF. In the current study, we evaluated the cytotoxicity of butylidenephthalide (BP), a major phthalide ingredient of Angelica sinensis, in fibrotic buccal mucosal fibroblasts (fBMFs) as well as various myofibroblast hallmarks, including the phenotypical characteristics and fibrosis-related markers. Our results demonstrated that myofibroblast activities, including collagen gel contraction, migration, invasion and wound healing abilities were inhibited in response to BP. The expression levels of myofibroblast marker, α-smooth muscle actin (α-SMA), fibronectin and type 1 collagen A1 were decreased after exposure of BP. Moreover, we found that the EMT-related markers, Twist, Snail and ZEB1 were all downregulated after BP treatment. Most importantly, our findings demonstrated that BP impeded the binding of Snail to the E-box region in the α-SMA promoter, which may lead to inhibition of the arecoline-induced myofibroblast activities. Collectively, our data indicated that BP reduced numerous myofibroblast features in fBMFs and hindered the binding of Snail to α-SMA, thereby may function as an effective and natural antifibrosis compound.

Down-regulation of miR-200b-targeting Slug axis by cyclosporine A in human gingival fibroblasts.

BACKGROUND/PURPOSE: Cyclosporine A (CsA) has been used as an immunosuppressive agent with a side effect of gingival overgrowth. It has been known that CsA-induced epithelial-mesenchymal transition (EMT) in gingiva, but the molecular mechanism has not been fully unveiled. The purpose of the study is to investigate functional roles of microRNAs in gingival overgrowth. METHODS: The effect of CsA on the expression of microRNA-200b (miR-200b) in normal human gingival fibroblasts (HGFs) was determined using qRT-PCR. Luciferase reporter assay and Western blot were utilized to examine the relationship between miR-200b and EMT inducer Slug. Cell proliferation was assessed by MTT assay. RESULTS: CsA was found to downregulate the miR-200b transcript in HGFs in a dose-dependent manner. Luciferase reporter assay confirmed that Slug was a direct target of miR-200b, and the CsA-induced cell proliferation and Slug upregulation were inhibited by overexpression of miR-200b. Additionally, the silence of Slug reversed the increased proliferation of HGFs by miR-200b inhibitor. CONCLUSION: Repression of miR-200b after CsA administration led to an increase in Slug expression. Our results suggested that miR-200b was an upstream effector of the CsA-induced EMT and may act as a therapeutic target for CsA-induced gingival overgrowth.

High-frequency pulsed low-level diode laser therapy accelerates wound healing of tooth extraction socket: An in vivo study.

BACKGROUND AND OBJECTIVE: This study aimed to evaluate the effects of high-frequency pulsed (HiFP) low-level laser therapy (LLLT) on early wound healing of tooth extraction sockets in rats. STUDY DESIGN/MATERIALS AND METHODS: Bilateral maxillary first molars were extracted from 6-week-old Sprague-Dawley rats. Sockets on the right were treated by HiFP low-level diode laser irradiation (904-910 nm); the left sides served as unirradiated controls. LLLT (0.28 W, 30 kHz, 200-ns pulse, 0.6% duty cycle, 61.2 J/cm2 total power density) was employed immediately after extraction and every 24 hours thereafter. The maxillae including the sockets were resected 3 or 7 days after extraction. Soft-tissue healing was evaluated on days 0, 3, and 7. The bone mineral content (BMC), bone volume (BV), and bone mineral density (BMD) of the extraction sockets were evaluated by microcomputed tomography, and histomorphometric analysis was carried out on day 7. Real-time PCR analysis of osteogenic marker expression and immunohistochemical detection of proliferating cell nuclear antigen (PCNA)-positive cells were performed on day 3. RESULTS: Compared with control sites, the un-epithelialized areas of the extracted sites were significantly reduced by irradiation (P = 0.04), and the BMC, BV, and BMD of laser-treated sites were significantly increased (P = 0.004, 0.006, and 0.009, respectively). On day 7, the mean height of newly formed immature woven bone was higher in laser-treated sites (P = 0.24). On day 3, laser-treated sites showed significantly higher osteocalcin mRNA expression (P = 0.04) and PCNA-positive cell numbers (P = 0.01). CONCLUSION: HiFP low-level diode laser irradiation enhanced soft- and hard-tissue healing of tooth extraction sockets. Lasers Surg. Med. 48:955-964, 2016. © 2016 Wiley Periodicals, Inc.

Dental hard tissue ablation using mid-infrared tunable nanosecond pulsed Cr:CdSe laser.

BACKGROUND AND OBJECTIVE: Mid-infrared erbium: yttrium-aluminum-garnet (Er:YAG) and erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers (2.94- and 2.78-µm, respectively) are utilized for effective dental hard tissue treatment because of their high absorption in water, hydroxide ion, or both. Recently, a mid-infrared tunable, nanosecond pulsed, all-solid-state chromium-doped: cadmium-selenide (Cr:CdSe) laser system was developed, which enables laser oscillation in the broad spectral range around 2.9 µm. The purpose of this study was to evaluate the ablation of dental hard tissue by the nanosecond pulsed Cr:CdSe laser at a wavelength range of 2.76-3.00 µm. STUDY DESIGN/MATERIALS AND METHODS: Enamel, dentin, and cementum tissue were irradiated at a spot or line at a fluence of 0-11.20 J/cm2 /pulse (energy output: 0-2.00 mJ/pulse) with a repetition rate of 10 Hz and beam diameter of ∼150 µm on the target (pulse width ∼250 ns). After irradiation, morphological changes, ablation threshold, depth, and efficiency, and thickness of the structurally and thermally affected layer of irradiated surfaces were analyzed using stereomicroscopy, scanning electron microscopy (SEM), and light microscopy of non-decalcified histological sections. RESULTS: The nanosecond pulsed irradiation without water spray effectively ablated dental hard tissue with no visible thermal damage such as carbonization. The SEM analysis revealed characteristic micro-irregularities without major melting and cracks in the lased tissue. The ablation threshold of dentin was the lowest at 2.76 µm and the highest at 3.00 µm. The histological analysis revealed minimal thermal and structural changes ∼20 µm wide on the irradiated dentin surfaces with no significant differences between wavelengths. The efficiency of dentin ablation gradually increased from 3.00 to 2.76 µm, at which point the highest ablation efficiency was observed. CONCLUSION: The nanosecond pulsed Cr:CdSe laser demonstrated an effective ablation ability of hard dental tissues, which was remarkably wavelength-dependent on dentin at the spectral range of 2.76-3.00 µm. These results demonstrate the potential feasibility of the use of pulsed Cr:CdSe laser as a novel laser system for dental treatment. Lasers Surg. Med. 48:965-977, 2016. © 2016 Wiley Periodicals, Inc.

Chemotherapeutic effects of luteolin on radio-sensitivity enhancement and interleukin-6/signal transducer and activator of transcription 3 signaling repression of oral cancer stem cells.

BACKGROUND/PURPOSE: Previously, we successfully identified oral cancer stem cells (OCSC) displaying enhanced stemness and tumorigenic potentials. In the study, we investigated the chemotherapeutic effect of the flavonoid luteolin, commonly found in fruits and vegetables, on targeting OCSC. METHODS: Oralspheres was applied to isolate OCSC. aldehyde dehydrogenase 1 activity and CD44 positivity of OCSC with luteolin treatment were assessed by flow cytometry analysis. Radio-sensitivity of OCSC treated with luteolin was examined. Invasion and colony-forming assays were performed to assess oncogenicity in OCSC. The expression of interleukin-6 (IL-6)/signal transducer and activator of transcription 3 (STAT3) was examined by enzyme-linked immunosorbent assay and western blot analysis. RESULTS: We showed that luteolin effectively inhibited the proliferation rate, self-renewal, aldehyde dehydrogenase 1 activity, and CD44 positivity of OCSC but did not cause significant cytotoxicity of normal epithelial cells. Moreover, luteolin restored radio-sensitivity in OCSC. Combined treatment with luteolin and radiation displayed synergistic effect on invasiveness and clonogenicity of OCSC. Mechanistically, treatment of luteolin resulted in inactivation of IL-6/STAT3 signaling. CONCLUSION: These results suggest that combined treatment of luteolin and radiation therapy can attenuate tumorigenicity of OCSC through IL-6/STAT3 signaling inactivation.

Er:YAG laser suppresses pro-inflammatory cytokines expression and inflammasome in human periodontal ligament fibroblasts with Porphyromonas gingivalis-lipopolysaccharide stimulation.

Background/purpose: Periodontitis is an inflammatory condition of the tooth-supporting structures triggered by the host's immune response towards the bacterial deposits around the teeth. It is well acknowledged that pro-inflammatory interleukin (IL)-6, IL-8, MCP-1 as well as the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome, are the key modulators in the activation of this response. Erbium-doped yttrium-aluminium-garnet (Er:YAG) laser, a solid-state crystal laser have been commonly used in the treatment of periodontal diseases. However, little is understood about the molecular mechanism of the Er:YAG laser, especially in targeting the host immune response brought on by periodontal pathogens. Hence, the current study focused on the protective effects of Er:YAG laser on periodontitis in-vitro in terms of pro-inflammatory cytokines, chemokines and NLRP3 inflammasome expressions. Materials and methods: Human periodontal ligament fibroblast (PDLFs) were first stimulated with lipopolysaccharides (LPS) from P. gingivalis (Pg-LPS) to simulate periodontitis. Cells were then irradiated with Er:YAG laser of ascending energy densities (3.6-6.3 J/cm2), followed by cell proliferation and wound healing assay. Next, the effects of Er:YAG laser on the expressions of IL-6, IL-8, MCP-1, NLRP3, and cleaved GSDMD were examined. Results: Pg-LPS was found to reduce cell's proliferation rate and wound healing ability in PDLFs and these were rescued by Er:YAG laser irradiation. In addition, LPS stimuli resulted in a marked upregulation in the secretion of IL-6, IL-8 and MCP-1 as well as the mRNA and protein expression of NLRP3 and cleaved-GSDMD protein whereas Er:YAG laser suppressed the elicited phenomena. Conclusion: To our knowledge, this is the first study to look into the laser's implication on the NLRP3 inflammasome in periodontitis models. Our study reveals a crucial role of Er:YAG laser in ameliorating periodontitis in-vitro through the modulation of IL-6, IL-8, MCP-1 and the NLRP3 inflammasome and highlights that the control of the NLRP3 inflammasome may become a potential approach for periodontitis.

Current status of Er:YAG laser in periodontal surgery.

Lasers have numerous advantageous tissue interactions such as ablation or vaporization, hemostasis, bacterial killing, as well as biological effects, which induce various beneficial therapeutic effects and biological responses in the tissues. Thus, lasers are considered an effective and suitable device for treating a variety of inflammatory and infectious conditions of periodontal disease. Among various laser systems, the Er:YAG laser, which can be effectively and safely used in both soft and hard tissues with minimal thermal side effects, has been attracting much attention in periodontal therapy. This laser can effectively and precisely debride the diseased root surface including calculus removal, ablate diseased connective tissues within the bone defects, and stimulate the irradiated surrounding periodontal tissues during surgery, resulting in favorable wound healing as well as regeneration of periodontal tissues. The safe and effective performance of Er:YAG laser-assisted periodontal surgery has been reported with comparable and occasionally superior clinical outcomes compared to conventional surgery. This article explains the characteristics of the Er:YAG laser and introduces its applications in periodontal surgery including conventional flap surgery, regenerative surgery, and flapless surgery, based on scientific evidence from currently available basic and clinical studies as well as cases reports.

Resveratrol attenuates advanced glycation end product-induced senescence and inflammation in human gingival fibroblasts.

Background/purpose: The accumulation of advanced glycation end products (AGEs) lead to a series of immune responses such as: increased oxidative stress and inflammation which contribute to the development of diabetic complications and periodontal disease. Resveratrol is a natural compound that has anti-oxidant and anti-inflammatory effects. Studies have found that diabetes-induced periodontitis is mainly caused by oxidative stress, aging and increased inflammation. In view of resveratrol has been proposed to have the ability in anti-oxidant and anti-inflammation in a variety of tissues. However, the role of resveratrol in diabetic periodontitis remains to be investigated. In this study, we aimed to investigate the role of resveratrol in preventing and treating diabetic periodontitis. Materials and methods: First, cell proliferation was measured in AGEs-treated human gingival fibroblast with or without resveratrol. We examined the reactive oxygen species (ROS) generation, senescence-associated beta-galactosidase (SA-ß-gal) and senescence marker p16 in human gingival fibroblasts (HGFs) stimulated with AGEs with or without the treatment of resveratrol. To determine whether resveratrol has the potential to regulate inflammaging which is mediated via the NF-κB signaling pathway and, the expression of p65 and p-IκB were also investigated. Furthermore, the concentration of interleukin (IL)-6 and IL-8 were also measured in AGEs-stimulated HGFs treated with or without resveratrol. Results: ROS generation, cell senescence, and the secretion of IL-6 and IL-8 were significantly upregulated following the treatment of AGEs. However, the administration of resveratrol suppresses the generation of IL-6 and IL-8 and cell senescence via inhibiting NF-κB signaling pathway. Our results revealed that resveratrol inhibits inflammaging by downregulating NF-κB signaling pathway. Conclusion: According to our findings, AGEs increase senescence and the production of proinflammatory cytokines in the gingiva, while the administration of resveratrol impedes inflammaging via suppressing NF-κB signaling pathway.

Quercetin ameliorates advanced glycation end product-induced wound healing impairment and inflammaging in human gingival fibroblasts.

Background/purpose: Diabetes mellitus (DM) and periodontal disease are both prevalent and chronic inflammatory disorders that have significant health impact. Many studies have pointed out that advanced glycation end-products (AGEs) in DM induces inflammaging, which is a pre-aging and hyperinflammatory condition, and it has been linked to a greater likelihood in developing periodontitis. Inflammaging in DM has been shown to be driven by AGEs-induced cell senescence, inflammatory cytokines, and oxidative stress, resulting in the degradation of periodontium. Quercetin has shown abilities to decrease inflammation and oxidative stress in a variety of tissues, however, the effect in diabetic periodontitis remains uncertain. Thus, the aim of this study was to investigate its impacts on inflammaging in diabetic periodontitis. Materials and methods: We examined cell proliferation in human gingival fibroblasts (HGF), wound healing, IL-6 and IL-8 secretions, cellular senescence expression, and the formation of reactive oxygen species (ROS) in response to AGE stimulation with and without Quercetin intervention. Following that, we looked into NF-κß activity to see if Quercetin mediate its effects via this pro-inflammatory signaling. Results: Quercetin at 20 µM and below did not have any impact on HGFs' cell proliferation rate. Quercetin intervention improved the AGEs-impaired wound healing, in addition to the attenuation of AGEs-induced ROS in a dose-dependent pattern. Moreover, Quercetin therapy dose-dependently inhibited AGEs-induced cell senescence activity along with its senescence associated secretion phenotype (SASP) secretions such as IL-6 and IL-8. Western blot analysis indicated that Quercetin was able to reverse the phosphorylation of p65 and Iκß in AGEs-stimulated HGFs, demonstrating it can modulate NF-κß pathway. Conclusion: Accumulation of AGEs can elicit inflammaging in HGFs, as seen by increased pro-inflammatory cytokines, cell senescence expression and oxidative stress. The results proposed that Quercetin is able to ameliorate inflammaging in diabetic periodontitis and improve wound healing via the suppression of NF-κß pathway and hence, may be a promising approach for treatment of diabetes-associated periodontitis.

Bromelain inhibits the inflammation and senescence effect in diabetic periodontitis: A preliminary in vitro study.

Background/purpose: Diabetes mellitus (DM) is a chronic metabolic disorder that affects millions of people worldwide. A growing evidence suggests that hyperglycemia in DM causes a pre-aging and pro-inflammatory condition known as inflammaging, which increases periodontitis susceptibility. Bromelain has been demonstrated to have anti-inflammatory and anti-aging properties in variety of tissues, but its effects on diabetic periodontitis remain unclear. Thus, the aim of this study is to investigate the its Bromelain's impact in diabetic periodontitis in terms of inflammation and senescence activity. Materials and methods: We assessed the wound healing capacity, production of pro-inflammatory cytokines Interleukin (IL)-6 and IL-8 and senescence marker p16 in human gingival fibroblasts (HGFs) in response to Advanced glycation end-products (AGEs) stimulant, with or without Bromelain treatment. The expression of p65, p-ERK, and p-p38 were also examined to elucidate whether Bromelain's anti-inflammaging activity is mediated through NF-κB and MAPK/ERK signaling pathway. Results: Bromelain concentrations ranging from 2.5 to 20 g/mL had no adverse effect on HGF cell proliferation. Bromelain improved wound healing in HGFs with AGEs stimulation. In addition, Bromelain suppressed the production of pro-inflammatory cytokines IL-6 and IL-8 in HGFs elicited by AGEs. Meanwhile, Bromelain treatment also inhibited the senescence activity and expression of p16 in AGEs-stimulated HGFs. Western blot analysis indicated that the upregulation of p-ERK, p-p38 and p65 induced by AGEs were inhibited by Bromelain in HGFs. Conclusion: These data suggest that excessive AGEs in the gingiva may lead to the accumulation of pro-inflammatory cytokines and marked senescence activity. Bromelain application may be helpful in enhancing wound healing by suppressing inflammaging via downregulation of NF-κB and MAPK/ERK signaling pathways in DM individuals with periodontal disease.

Anti-inflammaging effects of vitamin D in human gingival fibroblasts with advanced glycation end product stimulation.

Background/purpose: :Both periodontal disease and diabetes mellitus (DM) are long-term inflammatory disorders that are highly prevalent and have a significant health impact. Inflammaging, a state of pre-aging and hyperinflammatory state has been acknowledged for its role in DM patients to have heightened risk of periodontitis. Numerous evidences revealed that inflammaging contributed by cell senescence, acceleration of inflammation and oxidative stress participates in the destruction of periodontium in DM. Abilities of vitamin D in suppressing inflammation and oxidative stress have been revealed in a range of tissues, however in DM's gingival cells, the effect remain undefined. Materials and methods: : Under the stimulation of advanced glycation end-products (AGEs), we assessed the cell proliferation in human gingival fibroblast (HGF), IL-6 and IL-8 secretions, cellular senescence expression and generation of reactive oxygen species (ROS) with or without vitamin D intervention. Following that, we examined the expression of Nrf2 and HO-1 to see if vitamin D was able to modulate the anti-oxidant signaling. A knockdown experiment was then conducted to proof the participation of Nrf2 on the secretion of pro-inflammatory IL-6 and IL-8. Results: : Following the treatment of vitamin D, AGEs-elicited IL-6 and IL-8 production and cell senescence were dose-dependently repressed. Moreover, vitamin D attenuated AGEs-induced ROS in a dose-dependent pattern. Results from qRT-PCR demonstrated vitamin D reversed the suppression of Nrf2 and HO-1 induced by AGEs. Our findings revealed that the anti-inflammatory and anti-oxidant effect in vitamin D was mediated via the upregulation of Nrf2 expression. Conclusion: : These data showed that high levels of AGEs in the gingiva lead to inflammaging reflected by increased pro-inflammatory cytokines, cell senescence expression and oxidative stress. Vitamin D supplementation can reduce oxidative stress and inflammation via the upregulation of Nrf2 signaling and hence, may be a potential approach for treatment of diabetes-associated periodontitis.

Potential Therapeutic Applications of Natural Compounds in Diabetes-Associated Periodontitis.

Diabetes mellitus (DM) is a major worldwide health burden. DM is a metabolic disease characterized by chronic hyperglycemia, and if left untreated, can lead to various complications. Individuals with uncontrolled DM are more susceptible to periodontitis due to both a hyper-inflammatory host response and an impaired immune response. Periodontitis, on the other hand, may exacerbate DM by increasing both local and systemic inflammatory components of DM-related complications. The current standard for periodontal treatment in diabetes-associated periodontitis (DP) focuses mostly on reducing bacterial load and less on controlling the excessive host response, and hence, may not be able to resolve DP completely. Over the past decade, natural compounds have emerged as an adjunct approach for modulating the host immune response with the hope of curing DP. The anti-oxidant, anti-inflammatory, and anti-diabetic characteristics of natural substances are well-known, and they can be found in regularly consumed foods and drinks, as well as plants. The pathophysiology of DP and the treatment benefits of various bioactive extracts for DP will be covered in this review.