Protective effect and related mechanisms of curcumin in rat experimental periodontitis

Expression of TNF-α, omentin-1, and IL-6 before and after adjunctive treatment with a bioactive antimicrobial peptide periodontal gel

BACKGROUND

The objective of this study was to evaluate and compare the expression levels of TNF-α, omentin-1, and IL-6 in periodontitis patients before and after treatment with biological antimicrobial peptide (AMP) periodontal gel.

METHODS

There involved 86 periodontitis patients admitted to our hospital from January 2020 to March 2021. They were equally and randomly distributed into the study group and the control group. The efficacy and adverse reactions were compared between the two groups after treatment, Additionally, the sulcus bleeding index (SBI), plaque index (PLI), gingival index (GI), periodontal probing depth (PD), and levels of TNF-α, omentin-1, and IL-6 were measured before and after treatment.

RESULTS

After treatment, the total effective rate of the study group was significantly higher than that of the control group (p < 0.05), while the scores of four indicators (SBI, PLI, GI, and PD) and the levels of TNF-α, omentin-1, and IL-6 in the study group were evidently lower than the control group (p < 0.05). The study group had 1 case of mild irritant reaction, with an adverse reaction rate of 2.33% (1/43). And the control group had 1 case of nausea and 1 case of allergy, with an adverse reaction rate of 4.65% (2/43). The adverse reactions demonstrated no statistical difference between the two groups (χ2  = 0.345, p = 0.557).

CONCLUSIONS

The levels of TNF-α and IL-6 were highly expressed before the auxiliary therapy of biological AMP periodontal gel for periodontitis, alongside low expression of omentin-1. Subsequently, the biological antibacterial polypeptide periodontal gel demonstrated efficacy in the treatment of periodontitis.

A literature review of bioactive substances for the treatment of periodontitis: In vitro, in vivo and clinical studies

Periodontitis is a common chronic inflammatory disease of the supporting tissues of the tooth that involves a complex interaction of microorganisms and various cell lines around the infected site. To prevent and treat this disease, several options are available, such as scaling, root planning, antibiotic treatment, and dental surgeries, depending on the stage of the disease. However, these treatments can have various side effects, including additional inflammatory responses, chronic wounds, and the need for secondary surgery. Consequently, numerous studies have focused on developing new therapeutic agents for more effective periodontitis treatment. This review explores the latest trends in bioactive substances with therapeutic effects for periodontitis using various search engines. Therefore, this study aimed to suggest effective directions for therapeutic approaches. Additionally, we provide a summary of the current applications and underlying mechanisms of bioactive substances, which can serve as a reference for the development of periodontitis treatments.

AR-A014418, a glycogen synthase kinase-3β inhibitor, mitigates lipopolysaccharide-induced inflammation in rat dental pulp stem cells via NLR family pyrin domain containing 3 inflammasome impairment

Background/purpose

Cell pyroptosis and gingival inflammation have been implicated in periodontitis progression. Our previous study revealed that AR-A014418, a pharmacological inhibitor of glycogen synthase kinase-3β (GSK-3β), can enhance the migratory and osteogenic differentiation abilities of rat dental pulp stem cells (rDPSCs). The present study aimed to explore the effect of AR on the inflammation of rDPSCs.

Materials and methods

The primary rDPSCs were isolated and identified by flow cytometry, as well as Oil red O and Alizarin Red S staining. The rDPSCs were cultured and exposed to lipopolysaccharide (LPS) before treating them with different concentrations of AR-A014418. The cell viability was detected using the CCK-8 assay. The generation and secretion of pro-inflammatory cytokines (IL-18, TNF-α, L-1β, and IL-6) were examined by qPCR and ELISA, respectively. To investigate the activation of the NLRP3 inflammasome, the expression levels of pro-caspase 1, cleaved caspase 1, as well as NLRP3 were analyzed by western blotting and immunofluorescence, respectively.

Results

In the rDPSCs, LPS prohibited cell viability and enhanced the generation and secretion of pro-inflammatory cytokines. LPS upregulated NLRP3 and cleaved caspase-1 protein levels and promoted ASC speck formation in the rDPSCs. AR-A014418 administration effectively blocked the LPS-induced inflammation of the rDPSCs in a dose-dependent way. Mechanistically, AR-A014418 significantly restrained the up-regulation of NLRP3 and cleaved caspase-1 in LPS-treated rDPSCs.

Conclusion

Collectively, our findings suggest that AR-A014418 significantly mitigates LPS-induced inflammation of rDPSCs by blocking the activation of the NLRP3 inflammasome.

Brief literature review and comprehensive bioinformatics analytics unravel the potential mechanism of curcumin in the treatment of periodontitis

OBJECTIVE

Periodontitis is a chronic oral disease prevalent worldwide, and natural products are recommended as adjunctive therapy due to their minor side effects. Curcumin, a widely used ancient compound, has been reported to possess therapeutic effects in periodontitis. However, the exact mechanism underlying its activity remains unclear. In this context, the present study aimed to conduct computational simulations to uncover the potential mechanism of action of Curcumin in the treatment of periodontitis.

MATERIALS AND METHODS

Single-cell analysis was conducted using a dataset (i.e., GSE164241) curated from the Gene Expression Omnibus (GEO) database through an R package "Seurat package." Bulk RNA sequencing data were curated from GSE10334 and GSE16134 and processed by R package "Limma." Then, the marker genes in the single-cell transcriptome and differentially expressed genes (DEGs) in the bulk transcriptome were integrated. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses were also carried out to reveal their functionalities. Key targets were mined from their protein-protein interaction (PPI) network topologically. Afterward, molecular docking was performed. The top-ranked pose was subjected to molecular dynamics simulations to investigate the stability of the docking result.

RESULTS

FOS, CXCL1, CXCL8, and IL1B, were filtered after a series of selected processes. The results of molecular modeling suggested that except for IL1B, the Vena Scores of the rest exceeded -5 kcal/mol. Furthermore, the molecular dynamic simulation indicated that the binding of the CXCL8-Curcumin complex was stable over the entire 100 ns simulation.

CONCLUSION

The present study unlocked the binding modes of CXCL1, FOS, and CXCL8 with the Curcumin molecule, which were relatively stable, especially for CXCL8, hindering its promising potential to serve as the critical targets of Curcumin in periodontitis treatment.

"Medicine food homology" plants promote periodontal health: antimicrobial, anti-inflammatory, and inhibition of bone resorption

"Medicine food homology" (MFH) is a term with a lengthy history. It refers to the fact that a lot of traditional natural products have both culinary and therapeutic benefits. The antibacterial, anti-inflammatory and anticancer effects of MFH plants and their secondary metabolites have been confirmed by numerous research. A bacterially generated inflammatory illness with a complicated pathophysiology, periodontitis causes the loss of the teeth's supporting tissues. Several MFH plants have recently been shown to have the ability to prevent and treat periodontitis, which is exhibited by blocking the disease's pathogens and the virulence factors that go along with them, lowering the host's inflammatory reactions and halting the loss of alveolar bone. To give a theoretical foundation for the creation of functional foods, oral care products and adjuvant therapies, this review has especially explored the potential medicinal benefit of MFH plants and their secondary metabolites in the prevention and treatment of periodontitis.

Anti-Oxidant Multi-Functionalized Materials: Strontium-Substituted Monetite and Brushite as Delivery Systems for Curcumin

Curcumin has numerous biological activities and pharmaceutical applications related to its ability to inhibit reactive oxygen species. Herein, strontium-substituted monetite (SrDCPA) and strontium-substituted brushite (SrDCPD) were synthesized and further functionalized with curcumin with the aim to develop materials that combine the anti-oxidant properties of the polyphenol, the beneficial role of strontium toward bone tissue, and the bioactivity of calcium phosphates. Adsorption from hydroalcoholic solution increases with time and curcumin concentration, up to about 5-6 wt%, without affecting the crystal structure, morphology, and mechanical response of the substrates. The multi-functionalized substrates exhibit a relevant radical scavenging activity and a sustained release in phosphate buffer. Cell viability, morphology, and expression of the most representative genes were tested for osteoclast seeded in direct contact with the materials and for osteoblast/osteoclast co-cultures. The materials at relatively low curcumin content (2-3 wt%) maintain inhibitory effects on osteoclasts and support the colonization and viability of osteoblasts. The expressions of Alkaline Phosphatase (ALPL), collagen type I alpha 1 chain (COL1A1), and osteocalcin (BGLAP) suggest that curcumin reduces the osteoblast differentiation state but yields encouraging osteoprotegerin/receptor activator for the NFkB factor ligand (OPG/RANKL) ratio.

Local administration of curcumin-loaded nanoparticles enhances periodontal repair in vivo

The aim was to assess the influence of local application of curcumin-loaded nanoparticles on an experimental model of periodontal repair. Periodontitis was induced by ligatures on both lower first molars of rats. After 15 days, ligatures were removed ("treatment") and animals were randomly allocated to three experimental groups (n = 8/group): (i) 0.05 mg/ml curcumin-loaded nanoparticles, (ii) empty nanoparticles (vehicle control), and (iii) sterile saline (negative control). Experimental treatments were administered locally on days 0, 3, 5, 7, 9, and 11 after ligature removal. Animals were euthanized at 7 and 14 days. Bone repair was assessed by microcomputer tomography (µCT). Histological sections were stained with hematoxylin/eosin (H/E), Picrosirius Red, and Masson's trichrome. Expression of Runx-2 was studied by immunohistochemistry. Gene expression of Itgam, Arg1, and Inos was assessed by RT-qPCR. At 7 days, there was increased gene expression of Itgam and Arg1 and of the relative expression of Arg1/Inos in curcumin-treated animals, but no difference in any other outcomes. At 14 days, curcumin-loaded nanoparticles significantly increased bone repair and collagen content, as well as the number of osteocytes, percentage of extracellular matrix, and expression of Runx2. The results demonstrate that local administration of curcumin-loaded nanoparticles enhanced tissue repair in an experimental model of periodontal repair. Nanoparticle-encapsulated curcumin enhances early post-treatment repair of periodontal tissues.

Synergistic Effect of Silk Sericin and Curcumin to Treat an Inflammatory Condition

Inflammation-related diseases are recognized as the major cause of morbidity around the globe. In this study, the anti-inflammatory potential of sericin, curcumin, and their mixture was investigated in vivo and in vitro. Edema was induced via 1% carrageenan and then sericin (0.03, 0.06, 0.09 mg/ml), curcumin (1%, 2%, 3%), and their mixture doses were applied topically. The paw circumference and thickness were measured after 1-, 2-, 3-, 4-, 5-, and 6-hour post-carrageenan injection. The levels of IL-4 and IL-10 were measured from the serum. In mice fibroblast cells, sericin (20, 40, 60 μg/ml), curcumin (5, 10, 20 μM), and mixture concentrations were applied and then stimulated with lipopolysaccharide (LPS). Afterward, the cells were used for the analysis of gene expression, and the supernatant was collected for protein expression of IL-1β, IL-4, and IL-10. Our results demonstrated that sericin and curcumin caused a dose-dependent reduction in edema, whereas the mixture-treated group reduced the paw thickness and circumference most significantly (p = .0001). Furthermore, the mixture treatment of carrageenan-inflicted group increased the levels of anti-inflammatory cytokines, IL-4 (650.87 pg/ml) and IL-10 (183.14 pg/ml), in comparison to the carrageenan control. The in vitro data revealed that among all the treatment doses, the mixture-treated group has effectively reduced the gene (1.13-fold) and protein (51.9 pg/ml) expression of IL-1β in comparison to McCoy cells stimulated with LPS. Moreover, mixture treatment elevated the expression of IL-4 and IL-10 at genes (4.3-fold and 3.7-fold, respectively) and protein levels (169.33 and 141.83 pg/ml, respectively). The current study reports the enhanced anti-inflammatory effects of the mixture of curcumin and sericin through modulating expressions of interleukins in vitro and in vivo. Thus, natural products (curcumin and sericin)-based formulations have greater potential for clinical investigations.

Advanced materials and technologies for oral diseases

Oral disease, as a class of diseases with very high morbidity, brings great physical and mental damage to people worldwide. The increasing burden and strain on individuals and society make oral diseases an urgent global health problem. Since the treatment of almost all oral diseases relies on materials, the rapid development of advanced materials and technologies has also promoted innovations in the treatment methods and strategies of oral diseases. In this review, we systematically summarized the application strategies in advanced materials and technologies for oral diseases according to the etiology of the diseases and the comparison of new and old materials. Finally, the challenges and directions of future development for advanced materials and technologies in the treatment of oral diseases were refined. This review will guide the fundamental research and clinical translation of oral diseases for practitioners of oral medicine.

What Has Immunology Brought to Periodontal Disease in Recent Years?

Recent decades have shed a new light on the pathomechanism of periodontal inflammation. While classic periodontology concentrates on biofilm control, oral hygiene improvement, professional tooth cleaning and surgical correction of damaged periodontal tissues, new aspects of the destruction mechanisms are being raised. Among them, the greatest attention is paid to the influence of host response on the clinical manifestations of the disease. Numerous studies have proved that the shift from gingivitis to periodontitis is not a simple progress of the disease, but an event occurring only in susceptible individuals. Susceptibility may result from appearance of local factors facilitating biofilm accumulation and/or maturation, or from systemic features, among which over-reaction and prolonged agitation of non-specific component of inflammatory response is crucial. The present paper summarizes the association between periodontology and immunology and updates the knowledge accrued mostly in the recent years. After a brief explanation of advances in understanding of the disease aetiology, the most studied and potentially viable immunological markers of periodontal disease are presented. Possible new therapeutic strategies, exploiting knowledge about the nature of host response—immunomodulation and reduction of chronic oxidative stress—are also presented.

Therapeutic Potential of Polyphenol and Nanoparticles Mediated Delivery in Periodontal Inflammation: A Review of Current Trends and Future Perspectives

Periodontitis is an oral inflammatory process involving the periodontium, which is mainly caused by the invasion of periodontopathogenic microorganisms that results in gingival connective tissue and alveolar bone destruction. Metabolic products of the oral pathogens and the associated host immune and inflammatory responses triggered are responsible for the local tissue destruction. Numerous studies in the past decades have demonstrated that natural polyphenols are capable of modulating the host inflammatory responses by targeting multiple inflammatory components. The proposed mechanism by which polyphenolic compounds exert their great potential is by regulating the immune cell, proinflammatory cytokines synthesis and gene expression. However, due to its low absorption and bioavailability, the beneficial effects of these substances are very limited and it hampers their use as a therapeutic agent. To address these limitations, targeted delivery systems by nanoencapsulation techniques have been explored in recent years. Nanoencapsulation of polyphenolic compounds with different carriers is an efficient and promising approach to boost their bioavailability, increase the efficiency and reduce the degradability of natural polyphenols. In this review, we focus on the effects of different polyphenolic substances in periodontal inflammation and to explore the pharmaceutical significance of polyphenol-loaded nanoparticles in controlling periodontitis, which may be useful for further enhancement of their efficacy as therapeutic agents for periodontal disease.

Novel regimens of phytopolyphenols with cisplatin or memantine and ZnSO4 for synergistic inhibition of growth and gingipains of the cultured Porphyromonas gingivalis

Background/purpose

Porphyromonas gingivalis (P.g.) played a keystone pathogen not only in initiation and progression of periodontitis but also as a risk factor involved in systemic diseases (Alzheimer’s disease, cancers, diabetes, osteoporosis etc.). Developments of effective and safe drugs to inhibit P.g. growth are urgent. In this study, we aimed at approaching novel regimens so called (PTM) by combination of repurposing drugs including phytopolyphenols (P) (curcumin, tea polyphenols), targeting drugs (T) such as cisplatin or memantine and metal ions(M) (ZnSO₄).

Materials and methods

The synergistic (combination Index (CI) < 1) antiproliferation and anti-protease efficacies (IC50) of novel regimens on cultured P.g. were evaluated by OD600 and colorimetric method respectively.

Results

The results obtained revealed that these novel regimens (PTM) synergistically (combination index, CI < 1) exerted not only antiproliferative but also anti-gingipain protease effects of P.g. The concentrations for 50% inhibition (IC50) of novel regimens on P.g. growth and gingipains were greatly decreased as compared with those of cisplatin and memantine alone.

Conclusion

Since these novel regimens exerted potent anti-bacterial effects on both planktonic and biofilm P.g., it is encouraged for further preclinical and clinical trials.

Computed Tomography Three-Dimensional Reconstruction Algorithm in the Diagnosis of Periodontitis and Its Correlation with Hypertension

This study was aimed at exploring the value of iterative reconstruction (IR) algorithm to treat the periodontitis using computed tomography (CT) image and analyze the relationship between periodontitis and hypertension. 95 patients with periodontitis were selected, including 43 patients with periodontitis, 41 patients with advanced periodontitis and hypertension, and 11 patients with periodontitis and nonhigh blood pressure (NBP). The IR algorithm was introduced to the CT image scanning of them to reduce the noise. In addition, the CT value was statistically analyzed. High-sensitivity C-reactive protein (hs-CRP) and interleukin 6 (IL-6) were dramatically increased compared with periodontitis patients with NBP and with hypertension ( $P<0.05$ ). After the IR algorithm of the image, the quality, information, and mean square error (MSE) of the image were all effectively improved. Image with a 50% dose showed the lowest noise, but the reconstruction algorithm improved the low-contrast resolution. Moderate and severe periodontitis was independently related to hypertension. Inflammatory cytokines were independently related to hypertension of periodontitis patients ( $P<0.05$ ). Therefore, it was concluded that the IR algorithm could effectively improve the spatial resolution of the CT image when it was adopted to treat periodontitis and showed a high accuracy rate; the incidence of hypertension in patients with periodontitis was relatively high, and it had a certain relationship with periodontitis; and inflammatory cytokines were related to periodontitis and hypertension of patients.

A Study on the Use of Phase Transition Lysozyme-Loaded Minocycline Hydrochloride in the Local Treatment of Chronic Periodontitis

Periodontitis is the most important oral disease causing human tooth loss. Although supragingival and subgingival scaling is the main strategy of periodontitis clinical treatments, drug treatment has an indispensable auxiliary role to some degree. Periodontitis medical treatment is divided into systemically administered treatments and local periodontally administered treatments. Compared with systemic administration, local administration can increase local drug concentrations, reduce dosages, and prolong action times while also improving patient compliance and avoiding possible adverse effects due to systemic administration responses. However, some studies show that minocycline ointment, a clinical local drug commonly used in periodontal pockets, has an unstable release rate; 80% of the drug is usually released within 2-3 days after pocket placement. This release is not conducive to controlling periodontal infection and may hinder the periodontal tissue repair and regeneration. Therefore, choosing a suitable carrier for minocycline hydrochloride is necessary to control its local release in periodontal tissue. Phase transition lysozyme (PTL) has been widely used in many studies and the development of macromolecular carrier material, and we selected PTL as the carrier for minocycline hydrochloride drugs because of its good biocompatibility, good drug-carrying capacity, and stable release. Due to its release characteristics and simple preparation, PTL is a promising carrier material.

Antioxidant Effects of Curcumin Gel in Experimental Induced Diabetes and Periodontitis in Rats

This study aimed to evaluate the effect of curcumin gel on antioxidant marker level in experimental induced diabetes and periodontitis (EDP) in rats. Adult Wistar rats were randomized into five groups (20 each): (1) EDP treated with scaling and root planing (SRP) + curcumin gel (CU), (2) EDP treated with CU, (3) EDP treated with SRP, (4) EDP without treatment, and (5) systemically healthy and without ligature (control). Each group was subdivided equally into 4 subgroups of 5 rats. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ), and periodontitis was induced by a ligature. Blood samples were collected by cardiac puncture at 0, 7, 14, and 21 days to assess oxidative stress of malondialdehyde (MDA) and antioxidant enzymes of glutathione peroxidase (GPx), catalase (CAT), and suproxidase dismutase (SOD) levels. The results showed a significant increase in serum MDA and antioxidant enzyme levels in the untreated EDP group compared to the control group ( $p<0.05$ ). The adjuvant use of CU to SRP resulted in a significant reduction of MDA and CAT levels as compared to the SRP group ( $p<0.05$ ); however, significant reduction of GPX and SOD levels can be found only at day 7. It can be concluded that the decreased level of antioxidant enzymes can be construed as a result of decreased oxidative stress by curcumin therapy.

Pharmacological Therapies for the Management of Inflammatory Bone Resorption in Periodontal Disease: A Review of Preclinical Studies

Periodontitis, a highly prevalent multicausal chronic inflammatory and destructive disease, develops as a result of complex host-parasite interactions. Dysbiotic bacterial biofilm in contact with the gingival tissues initiates a cascade of inflammatory events, mediated and modulated by the host's immune response, which is characterized by increased expression of several inflammatory mediators such as cytokines and chemokines in the connective tissue. If periodontal disease (PD) is left untreated, it results in the destruction of the supporting tissues around the teeth, including periodontal ligament, cementum, and alveolar bone, which lead to a wide range of disabilities and poor quality of life, thus imposing significant burdens. This process depends on the differentiation and activity of osteoclasts, the cells responsible for reabsorbing the bone tissue. Therefore, the inhibition of differentiation or activity of these cells is a promising strategy for controlling bone resorption. Several pharmacological drugs that target osteoclasts and inflammatory cells with immunomodulatory and anti-inflammatory effects, such as bisphosphonates, anti-RANK-L antibody, strontium ranelate, cathepsin inhibitors, curcumin, flavonoids, specialized proresolving mediators, and probiotics, were already described to manage inflammatory bone resorption during experimental PD progression in preclinical studies. Meantime, a growing number of studies have described the beneficial effects of herbal products in inhibiting bone resorption in experimental PD. Therefore, this review summarizes the role of several pharmacological drugs used for PD prevention and treatment and highlights the targeted action of all those drugs with antiresorptive properties. In addition, our review provides a timely and critical appraisal for the scientific rationale use of the antiresorptive and immunomodulatory medications in preclinical studies, which will help to understand the basis for its clinical application.

Anti-Periodontopathogenic Ability of Mangrove Leaves (Aegiceras corniculatum) Ethanol Extract: In silico and in vitro study

OBJECTIVE

 Mangrove (Aegiceras corniculatum) is an abundant natural marine resource of Indonesia, which can be explored for treating periodontal disease due to its potential as immunoregulatory, antibacterial, and antioxidant properties. The objective of this study was to investigate the active compound from Indonesian mangrove leaf extract (A. corniculatum) (MLE) for developing a herbal-based mouthwash through in silico and in vitro studies.

MATERIALS AND METHODS

 Phytochemistry and liquid chromatography-high resolution mass spectrometry (LC-HRMS) were done to explore the active compounds in MLE. Chemistry screening and interaction, absorption, distribution, metabolism, and excretion (ADME), molecular docking simulation, and visualization of MLE active compounds as anti-inflammatory, antioxidant, and antibacterial were investigated in silico The inhibition zone of MLE against Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), and Fusobacterium nucleatum (Fn) as periodontopathogenic bacterias was performed by diffusion method. Doxycycline 100 mg was used as a positive control, as a treatment group, there were five groups, namely 0%, 25%, 50%, 75%, and 100% MLE.

RESULTS

 Alkaloid, saponin, flavonoid, triterpenoid, steroid, tannin, and quinone were detected in MLE. A high concentration of (-)epicatechin and coumaric acid (CA) were found in MLE. MLE in 100% concentration has the most effective ability to inhibit Fn, Pg, Aa growth in vitro. (-)-Epicatechin has a higher negative binding affinity than CA that can enhance heat shock protein (HSP)-30, HSP-70, HSP-90, interleukin-10, and FOXP3 and also inhibit interleukin-6, peptidoglycan, flagellin, and dectin in silico.

CONCLUSION

 MLE of A. corniculatum has antioxidant, anti-inflammatory, and antibacterial activities that can be a potential raw material for developing a herbal-based mouthwash.

Effects of Curcumin and Tetracycline Gel on Experimental Induced Periodontitis as an Anti-Inflammatory, Osteogenesis Promoter and Enhanced Bone Density through Altered Iron Levels: Histopathological Study

Adjunctive use of antimicrobials with scaling and root planing (SRP) is necessary to better eradicate dental biofilm. Tetracycline (T) is the most commonly used antimicrobial; however, it has limitations. This study evaluates the effect of curcumin (CU) as adjunct to SRP on inflammatory markers, collagen fiber deposition, and altered iron level. A total of 32 Wistar rats were divided into five groups: no experimental periodontitis (healthy control), experimental periodontitis (EPD), EPD treated with SRP alone (SRP), EPD treated with SRP+T (SRP+T), and EPD treated with SRP+CU (SRP+CU). After 2 and 4 weeks of treatment, tissue samples were assessed by hematoxylin and eosin, and special stains (Perls’ stain and Masson’s Trichrome) for counting of inflammatory cells, angiogenesis, collagen fibers, and iron deposition. Significant reductions in inflammatory cells infiltration and alveolar bone resorption with angiogenesis and collagen fibers deposition were detected after 2 and 4 weeks in both SRP+T and SRP+CU groups. SRP+CU resulted in a significant reduction in osteoclast numbers (week 2) and iron deposition (week 4) in bone trabeculae as compared to SRP and SRP+T groups. The adjunctive use of CU showed comparable results to T in the reduction in inflammation and bone resorption. Furthermore, CU has potential osteogenesis and healing effects.

Circular RNA HECTD1 knockdown inhibits transforming growth factor-beta/ small mothers against decapentaplegic (TGF-β/Smad) signaling to reduce hypertrophic scar fibrosis

Scars are nearly impossible to avoid after a skin injury, but despite advancements in the treatment modalities, they remain a clinical problem, especially hypertrophic scars (HS). Many studies include the mechanism of formation and inhibition of HS, but it is not fully understood yet. Circular RNA HECTD1 (circHECTD1), for the first time, has been found to have roles in HS physiology. We determined the relative circHECTD1 levels in HS fibrous cells and tissues by RT-qPCR. Afterward, the effect of circHECTD1 knockdown on the proliferation, migration, invasion, fibrosis, and Transforming Growth Factor-beta/small mothers against decapentaplegic (TGF-β/Smad) signaling was studied using CCK-8, wound healing, Transwell, and western blot assays. After the role of circHECTD1 was clarified, its targeted micro RNA (miR) was predicted using the Starbase database, and we constructed a miR-142-3p mimic to study the details of its regulation mechanism. We used the TargetScan database to predict the downstream target high mobility group box 1 (HMGB1) of miR-142-3p, and the luciferase report assay verified the binding, and then its effect was determined by RT-qPCR. circHECTD1 is highly expressed in HS tissues and human skin hypertrophic scar fibroblasts (HSF); its loss of function inhibits cell proliferation, migration, invasion, fibrosis, and TGF-β/Smad signaling. However, miR-142-3p inhibitor reverses the effect of circHECTD1 on all the above-mentioned aspects, including HMGB1 expression. In conclusion, circHECTD1 knockdown interrupts TGF-β/Smad signaling through miR-142-3p/HMGB1 and suppresses scar fibrosis.

Photodynamic Therapy with Natural Photosensitizers in the Management of Periodontal Disease Induced in Rats

This study aims to investigate the effect of new natural photosensitizers (PS) (based on oregano essential oil, curcuma extract, and arnica oil) through in vitro cytotoxicity and biological tests in rat-induced periodontal disease, treated with photodynamic therapy (aPDT). The cytotoxicity of PS was performed on human dental pulp mesenchymal stem cells (dMSCs) and human keratinocyte (HaCaT) cell lines. Periodontal disease was induced by ligation of the first mandibular molar of 25 rats, which were divided into 5 groups: control group, periodontitis group, Curcuma and aPDT-treated group, oregano and aPDT-treated group, and aPDT group. The animals were euthanized after 4 weeks of study. Computed tomography imaging has been used to evaluate alveolar bone loss. Hematological and histological evaluation showed a greater magnitude of the inflammatory response and severe destruction of the periodontal ligaments in the untreated group.. For the group with the induced periodontitis and treated with natural photosensitizers, the aPDT improved the results; this therapy could be an important adjuvant treatment. The obtained results of these preliminary studies encourage us to continue the research of periodontitis treated with natural photosensitizers activated by photodynamic therapy.

Study on the role of pyroptosis in bone resorption induced by occlusal trauma with or without periodontitis

BACKGROUND AND OBJECTIVE

Occlusal trauma is considered to be a contributing factor to bone loss associated with inflammatory periodontal disease. We hypothesized that pyroptosis, a recently discovered inflammation-induced programmed cell death pathway, plays a role in occlusal trauma.

MATERIALS AND METHODS

The occlusal trauma model was established using a cemented 1-mm elevated computer-aided design and manufacturing (CAD/CAM) metal crown. The periodontitis model was established by periodontal wire ligation with lipopolysaccharide (LPS) injection. The rats were sacrificed at 1, 2, 3, and 4 weeks. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to analyze the expression of pyroptosis-, inflammation-, and osteoclast-related markers. Micro-computed tomography (micro-CT) was used to determine bone morphology parameters. Tissue morphology was evaluated using hematoxylin and eosin staining (H&E). Osteoclasts were identified using tartrate-resistant acid phosphatase (TRAP) staining. The expression and distribution of factors related to pyroptosis and inflammation were evaluated by immunohistochemistry (IHC). The colocalization of dead cells and cysteinyl aspartate-specific proteinase-1 (caspase-1)-positive cells was analyzed by immunofluorescence.

RESULTS

Quantitative real-time polymerase chain reaction and IHC results showed that occlusal trauma induced the expression of pyroptotic factors during the early stages, while occlusal trauma with periodontitis upregulated the expression of pyroptotic factors at the later stages. The results of qRT-PCR, TRAP staining, and micro-CT showed that occlusal trauma with periodontitis increased the production of proinflammatory cytokines, leading to severe bone loss. Glyburide, an NOD-like receptor pyrin domain containing protein 3 (NLRP3)inhibitor, reduced the expression of pyroptosis markers induced by occlusal trauma with periodontitis and reversed bone resorption.

CONCLUSIONS

Pyroptosis was involved in bone loss induced by occlusal trauma with or without periodontitis, while glyburide reversed inflammation and bone resorption.

Effects of grape seed proanthocyanidins on the expression of inflammatory mediators in gingival epithelial cells

OBJECTIVES

This study aims to determine the effect of grape seed proanthocyanidin (GSP) pretreatment on lipopolysaccharide (LPS)-induced inflammation of human gingival epithelial cells (HGECs).

METHODS

HGECs were cultivated with different concentrations of GSPs (0, 1, 5, 10, 20, 40, 60, 80, 100 μg·mL-1) for 6, 12, 24, and 48 h. CCK-8 was used to detect the proliferation activity of HGECs. HGECs were treated with different concentrations of GSPs (0, 10, 20, and 40 μg·mL-1) for 24 h and then cultured with 1.0 μg·mL-1 LPS. Enzyme-linked immunosorbent assay (ELISA) was used to detect the expression levels of pro-inflammatory cytokine tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 and anti-inflammatory cytokines IL-4, IL-10, and transforming growth factor-β (TGF-β). Quantitative real-time polymerase chain reaction (QRT-PCR) was used to detect the mRNA expression levels of TNF-α, IL-1β, IL-6, IL-4, IL-10, and TGF-β.

RESULTS

When the GSP concentration was 0-40 μg·mL-1, the cell proliferation had no significant difference. When the action time reached 24 h, the cell proliferation was the highest. The results of ELISA and QRT-PCR showed that 10, 20, and 40 μg·mL-1 GSPS decreased the expression levels of TNF-α, IL-1β, and IL-6 (P<0.05) and increased the expression levels of IL-4, IL-10, and TGF-β compared with 0 μg·mL-1 GSPS (P<0.05).

CONCLUSIONS

GSPS (0-40 μg·mL-1) has no significant effect on the proliferation activity of HGECs. Pretreatment with GSPS can inhibit the expression of pro-inflammatory factors and enhance the expression of anti-inflammatory factors. Hence, GSPS has a certain preventive effect on the resistance of HGECs to the stimulation of endotoxin.

Curcumin May Prevent Basement Membrane Disassembly by Matrix Metalloproteinases and Progression of the Bladder Cancer

Authors present a review of crucial mechanisms contributing to the invasion of the basement membrane (BM) of the urothelium by cancer cells and to the progression of bladder cancer (BC). The breeching of the urothelial BM, facilitated by an aberrant activation of matrix metalloproteinases (MMP) is particularly perilous. Inhibition of activation of these proteinases constitutes a logic opportunity to restrain progression. Because of limited efficacy of current therapeutic methods, the search for the development of alternative approaches constitutes "the hot spot" of modern oncology. Recent studies revealed significant anticancer potential of natural phytochemicals. Especially, curcumin has emerged as a one of the most promising phytochemicals and showed its efficacy in several human malignancies. Therefore, this article addresses experimental and clinical data indicating multi-directional inhibitory effect of curcumin on the growth of bladder cancer. We particularly concentrate on the mechanisms, by which curcumin inhibits the MMP's activities, thereby securing BM integrity and alleviating the eventual cancer invasion into the bladder muscles. Authors review the recently accumulating data, that curcumin constitutes a potent factor contributing to the more effective treatment of the bladder cancer.

Comparison of the efficacy of sonic irrigation and conventional syringe irrigation in the removal of curcumin and triple antibiotic paste from root canals

Background. The present study aimed to compare the efficacy of sonic irrigation and conventional syringe irrigation (CSI) in terms of curcumin (CUR) and triple antibiotic paste (TAP) removal from a standardized groove artificially created in root canals.

Methods. The root canals of 72 anterior maxillary teeth were prepared using the Reciproc system to size R50. The teeth were split longitudinally, and a standardized groove was created in the apical region of one root half. The standardized grooves were filled with CUR or TAP with the exclusion of six teeth that served as the negative control group, and then the root halves were reassembled. The teeth were divided into two subgroups according to the irrigation protocols used: sonic activation with EndoActivator (EA) or CSI (n=15). After the removal of the medicament, the residual medicament was assessed under a stereomicroscope. Kruskal-Wallis and Mann-Whitney U tests were used for statistical analyses (P = 0.05).

Results. The EA sonic activation method was significantly more efficient in removing CUR medicament from the root canals. Considering the medicament types, more CUR than TAP was removed from the root canals using both CSI and the EA (sonic activation) system (P < 0.05).

Conclusion. As compared with CSI, the EA was not significantly more efficient in removing TAP, but it was significantly more effective than CSI in removing CUR.

Design and development of electrospun SPEEK incorporated with aminated zirconia and curcumin nanofibers for periodontal regeneration

Periodontal disease disturbs the supportive tissues around the teeth such as connective tissue, gingival tissue, periodontal ligaments and alveolar bone. Previously, treatment of periodontitis was embattled by repopulating the affected site with cells that has capacity to regenerate damaged tissue by endorsing the perception of guided tissue regeneration but it entails additional surgery owing to non-biodegradability. Biodegradable polymeric nanofibrous scaffold imitating extracellular matrix (ECM) delivering functionalized nanoparticles loaded with therapeutic drug have the ability to support cellular functions thereby enhancing regeneration. Present study explores novel amine functionalized zirconia nanoparticle loaded curcumin incorporated SPEEK nanofibrous scaffolds to address periodontal regeneration. Zirconia - crown of dental therapeutics, its amine functionalization further enhanced the strength and cyto-compatibility. Carbon-Silica NMR (59.9 and 69.8 ppm), FT-IR (3426 cm^-1), EDAX and XRD (28.9°_, 31.6° and 38.2° pertaining to [-1 1 1], [1 1 1] and [1 2 0] planes) analysis confirmed the effective functionalization of the zirconia nanoparticle with the amine group. Electrospinning was carried out at a voltage of 20 kV and flow rate of 0.05 ml/h. Fabricated nanofibers were highly dense, porous with interconnected fibrous structures that bio-mimic ECM. They exhibited an average diameter of 187 ± 2 nm (SPEEK), 192 ± 2 nm (SPEEK + NH₂-ZrO₂), and 256 ± 17 nm (SPEEK + NH₂-ZrO₂+Cur). Extensively discovered anti-bacterial traits of curcumin supplemented the advantage for the treatment of periodontitis. Incorporated materials improve the physico-chemical, mechanical and biological characteristics of nanofibers. FT-IR, EDAX and XRD analysis of the fabricated nanofibrous scaffold demonstrated the effective incorporation of aminated zirconia loaded curcumin. Results of cyto-compatibility analysis of SPEEK + NH₂-ZrO₂+Cur nanofibrous scaffold depicted a cell viability of 100 ± 1.62%. Results of anti-bacterial assay with zone of inhibition was 6.5 ± 0.5 mm (SPEEK), 7.5 ± 1 mm (SPEEK + NH₂-ZrO₂), and 8 ± 1 mm (SPEEK + NH₂-ZrO₂+Cur). Thus, the fabricated bio-material is cyto-compatible, non-toxic and effective against pathogens exploiting higher potential for periodontal regeneration applications.

A review of therapeutic potentials of turmeric (Curcuma longa) and its active constituent, curcumin, on inflammatory disorders, pain, and their related patents

Turmeric (Curcuma longa) and its constituent, curcumin, have been used for their therapeutic properties for a long time. Most of the medicinal impacts of turmeric and curcumin might be attributed to their anti-inflammatory, antinociceptive, and antioxidant effects. In the present review, the preventive and therapeutic potentials of turmeric and its active constituent, curcumin, on inflammatory disorders and pain as well as patents related to their analgesic and anti-inflammatory effects, have been summarized to highlight their value on human health. A literature review was accomplished in Google Scholar, PubMed, Scopus, Google Patent, Patentscope, and US Patent. Several documents and patents disclosed the significance of turmeric and curcumin to apply in several therapeutic, medicinal, and pharmaceutical fields. These phytocompounds could be applied as a supplementary therapy in phytotherapy, inflammatory disorders such as arthritis, inflammatory bowel diseases, osteoarthritis, psoriasis, dermatitis, and different types of pain including neuropathic pain. However, because of inadequate clinical trials, further high-quality studies are needed to firmly establish the clinical efficacy of the plant. Consistent with the human tendency to the usage of phytocompounds rather than synthetic drugs, particular consideration must be dedicated to bond the worth of turmeric and curcumin from basic sciences to clinical applications.

Quercetin Decreased Alveolar Bone Loss and Apoptosis in Experimentally Induced Periodontitis Model in Wistar Rats

BACKGROUND

Quercetin is a flavonoid which has potent anti-inflammatory, antibacterial, and antioxidant effect. Purpose of this study was to evaluate effects of quercetin on alveolar bone loss and histopathological changes in ligature-induced periodontitis in rats.

METHODS

Wistar rats were divided into four experimental groups: non-ligated control (C, n=8) group; periodontitis (P, n=8) group; ligature and low dose quercetin group (75 mg/kg/day quercetin, Q75 group, n=8); ligature and high dose quercetin group (150 mg/kg/day quercetin, Q150 group, n=8). Silk ligatures were placed at gingival margin of lower first molars of mandibular right quadrant. Study duration was 15 days, and animals were sacrificed end of this period. Changes in alveolar bone levels were clinically measured and tissues were immunohistochemically examined, matrix metalloproteinase 8 (MMP 8), inducible nitric oxide synthase (iNOS), tissue inhibitor of metalloproteinase 1 (TIMP 1), Cysteine-aspartic proteases 3 (Caspase 3), and tartrate-resistant acid phosphatase (TRAP) positive osteoclast cells, osteoblast, and neutrophil counts were also determined.

RESULTS AND DISCUSSION

Alveolar bone loss was highest in P group, and differences among P, Q75, and Q150 groups were significant. Both doses of quercetin decreased TRAP+ osteoclast cells and increased osteoblast cells. Inflammation in P group was also higher than those of C, Q75, and Q150 groups indicating anti-inflammatory effect of quercetin. iNOS, MMP-8, and caspase-3 levels were highest, and TIMP-1 expression was lowest in P group; differences were statistically significant.

CONCLUSION

Within limits of this study, it can be suggested that quercetin administration may reduce alveolar bone loss by increasing osteoblastic activity, decreasing osteoclastic activity, apoptosis, and inflammation in an experimental model of periodontitis.

Clinical efficacy of curcumin versus chlorhexidine as an adjunct to scaling and root planing for the treatment of periodontitis: A systematic review and meta-analysis

This study aims to evaluate the clinical efficacy of curcumin versus chlorhexidine as adjuncts to scaling and root planing (SRP) for periodontitis treatment. We searched PubMed, EMbase, Cochrane Library, and ClinicalTrials.gov from inception to February 18, 2021 and identified studies with relevant randomized controlled trials (RCTs) using curcumin or chlorhexidine as an adjunct to SRP. Nine RCTs involving 420 patients/sites were included. A meta-analysis with a random-effects model revealed that curcumin and chlorhexidine, as an adjunct to SRP, reduced probing pocket depth (PPD) at similar levels during a 3-, 4-, 6-, and 12-week follow-up. No significant differences were observed in reducing clinical attachment loss (CAL) between curcumin and chlorhexidine as an adjunct to SRP at 4 weeks and 6 weeks. Furthermore, gingival index (GI) and plaque index (PI) were similar using curcumin versus chlorhexidine as an adjunct to SRP at the 4-week-, 6-week-, and 12-week follow-up. Based on the available evidence in RCTs, compared with chlorhexidine as an adjunct to SRP, curcumin has a similar effect on reducing PPD, CAL, GI, and PI. The quality of evidence is low, limited by the number of studies and their limitations. Further studies are needed to firmly establish the clinical efficacy of curcumin.

Effects of curcumin gel on osteoclastogenic bone markers in experimental periodontitis and alveolar bone loss in wistar rats

BACKGROUND/PURPOSE

Curcumin has anti-inflammatory impacts and was suggested as an inflammatory disease therapy. This study aimed to investigate the implications of curcumin gel on experimental periodontitis (EPD) and alveolar bone loss in rats.

MATERIALS AND METHODS

In this study, twenty-four male Wistar rats were divided equally into four groups: negative control (with no EPD); positive control (EPD induced around lower centrals without treatment); control-treated group: EPD treated with chlorhexidine; and test EPD group treated with curcumin. After 30 days, the serum concentrations of RANKL and IL-1β were measured via ELISA. All animals were sacrificed, and mandibular central incisors with the periodontium were removed. The lingual probing depth and radiographical alveolar bone loss were measured, then samples processed for routine preparation of H&E stained sections and histologically assessed for counting inflammatory cells, osteoclasts, and PDL width.

RESULTS

A significant decrease in the inflammatory cells infiltration, probing depth, and osteoclast numbers with the improvement of PDL associated with a reduction in RANKL and IL-1β serum concentration were seen in both EPD treated groups.

CONCLUSION

Curcumin is as effective as chlorhexidine in treating experimental periodontitis in rats. It was demonstrated to stop bone destruction related to periodontitis by regulating the RANKL and IL-1β markers level in the blood.

Curcumin: A review of experimental studies and mechanisms related to periodontitis treatment

Curcumin is the main active ingredient of turmeric, which has a wide range of pharmacological effects, including antitumor, antibacterial, anti-inflammatory, anti-oxidation, immune regulation, and so on. Periodontitis is a prevalent oral inflammatory disease caused by a variety of factors. In recent years, many studies have shown that curcumin has a potential role on the treatment of periodontitis. Curcumin has been used in research related to the treatment of periodontitis in the form of solution, chip, gel, and capsule. Combined with other periodontitis treatment methods, such as scaling and root planing (SRP) and photodynamic therapy (PDT), can enhance curcumin's efficacy in treating periodontitis. In addition to natural curcumin, chemically modified curcumin, such as 4-phenylaminocarbonyl bis-demethoxy curcumin (CMC 2.24) and 4-methoxycarbonyl curcumin (CMC 2.5), have also been used in animal models of periodontitis. Here, this paper reviews the research progress of curcumin on the treatment of periodontitis and its related mechanisms.

Fisetin attenuates periodontitis through FGFR1/TLR4/NLRP3 inflammasome pathway

The purpose of the present study was to investigate the pharmacological effect of Fisetin on experimental periodontitis in rats and explore its potential mechanism. The ligature/LPS method was used to induce periodontitis in rats. LPS was employed to cause inflammation in Human gingival fibroblasts (HGF). The transfections with FGFR1 SiRNA, NLRP3 SiRNA and the selective TLR4 inhibitor TAK242 were used to investigate the mechanism of Fisetin-mediated inflammatory reaction in LPS-induced HGF. As a result, Fisetin reduced the alveolar bone gap, reversed histopathological lesion and inhibited serum inflammatory cytokine concentration in periodontitis rats. Fisetin decreased the inflammatory cytokine contents in the supernatant of LPS-induced HGF. The inhibitory effect of Fisetin might be attributed to FGFR1/TLR4/NLRP3 inflammasome pathway both in vivo and in vitro. The suppressions of FGFR1, TLR4 and NLRP3 proved that FGFR1/TLR4/NLRP3 signaling was involved in the Fisetin-mediated inflammatory response. Fisetin also inhibited NLRP3 priming. The data demonstrated that Fisetin attenuated periodontitis by inhibiting inflammatory reaction via FGFR1/TLR4/NLRP3 inflammasome pathway.

Therapeutic effect of curcumin on oral diseases: A literature review

Curcumin (diferuloylmethane) is a polyphenol compound extracted from the rhizome of the plant Curcuma longa. It has the feature of being a yellow or orange pigment with a variety of biological properties, including anti-inflammation, antioxidation, anti-tumor, anti-bacteria, anti-fungus, and wound healing. Previous studies have reported the role of curcumin in treating different inflammatory diseases and tumors in vitro and in vivo. Recently, it has been demonstrated that curcumin has therapeutic benefits in oral mucosal diseases, periodontal diseases, and mouth neoplasms. In this review, we will focus on the therapeutic effects of curcumin on oral diseases.

From Simple Mouth Cavities to Complex Oral Mucosal Disorders-Curcuminoids as a Promising Therapeutic Approach

Oral diseases are among the most common encountered health issues worldwide, which are usually associated with anomalies of the oral cavity, jaws, and salivary glands. Despite the availability of numerous treatment modalities for oral disorders, a limited clinical response has been observed because of the inefficacy of the drugs and countless adverse side effects. Therefore, the development of safe, efficacious, and wide-spectrum therapeutics is imperative in the battle against oral diseases. Curcumin, extracted from the golden spice turmeric, is a well-known natural polyphenol that has been extensively studied for its broad pleiotropic attributes and its ability to modulate multiple biological processes. It is well-documented to target pro-inflammatory mediators like NF-κB, ROS, COX-2, IL-1, IL-2, TGF-β, growth factors, apoptotic proteins, receptors, and various kinases. These properties make curcumin a promising nutraceutical in the treatment of many oral diseases like oral submucous fibrosis, oral mucositis, oral leukoplakia, oral erythroplakia, oral candidiasis, aphthous stomatitis, oral lichen planus, dental caries, periodontitis, and gingivitis. Numerous in vitro and in vivo studies have shown that curcumin alleviates the symptoms of most of the oral complications, including the inhibition of the progression of oral cancer. In this regard, many clinical trials have been completed, and many are ongoing to investigate the "curcumin effect" in oral maladies. Therefore, the current review delineates the mechanistic framework of curcumin's propensity in curbing oral diseases and present outcomes of the clinical trials of curcumin-based therapeutics that can provide a breakthrough in the clinical management of these diseases.

Recent Development of Active Ingredients in Mouthwashes and Toothpastes for Periodontal Diseases

Periodontal diseases like gingivitis and periodontitis are primarily caused by dental plaque. Several antiplaque and anti-microbial agents have been successfully incorporated into toothpastes and mouthwashes to control plaque biofilms and to prevent and treat gingivitis and periodontitis. The aim of this article was to review recent developments in the antiplaque, anti-gingivitis, and anti-periodontitis properties of some common compounds in toothpastes and mouthwashes by evaluating basic and clinical studies, especially the ones published in the past five years. The common active ingredients in toothpastes and mouthwashes included in this review are chlorhexidine, cetylpyridinium chloride, sodium fluoride, stannous fluoride, stannous chloride, zinc oxide, zinc chloride, and two herbs—licorice and curcumin. We believe this comprehensive review will provide useful up-to-date information for dental care professionals and the general public regarding the major oral care products on the market that are in daily use.

Adjuvant effects of curcumin as a photoantimicrobial or irrigant in the non-surgical treatment of periodontitis: Systematic review and meta-analysis

AIM

Curcumin (CUR) has been used clinically in several studies as a subgingival irrigant or as a photoantimicrobial in combination with a blue light-emitting diode (LED) in antimicrobial photodynamic therapy (aPDT) adjuvant to scaling and root planing (SRP). The aim of this study was to assess the effectiveness of CUR as an irrigant or as a photoantimicrobial in conjunction with the blue LED in aPDT adjuvant to SRP, compared to SRP as conventional mechanical treatment.

MATERIALS AND METHODS

Fifteen randomized controlled trials (RCT) were included in a qualitative analysis after researching the databases: PubMed / MEDLINE, SCOPUS, EMBASE, Cochrane Central, Web of Science and Scielo. Manual searches were also performed. Five studies were submitted to quantitative analysis, evaluating periodontal clinical parameters such as probing depth (PD) and clinical attachment level (CAL).

RESULTS

The obtained results have shown clinical benefits in PD reduction and CAL gains at 3 months with the use of CUR as adjuvant therapy to SRP, both as an irrigant or photoantimicrobial, in comparison with SRP monotherapy.

CONCLUSION

Currently, there is evidence that treatment with CUR applied as irrigant or in conjunction with the blue LED as aPDT presents superior clinical results in the short term, for clinical periodontics parameters like as PD reduction and CAL gain, when compared to SRP monotherapy in the non-surgical treatment of periodontitis. However, these results cannot be proven in the long term.

Inhibitory effects of curcumin against cytotoxicity of Porphyromonas gingivalis outer membrane vesicles

OBJECTIVE

The purpose of this study was to examine whether curcumin, a turmeric root extract, protects human gingival epithelial (HGE) cells from the cytotoxic effects ofPorphyromonas gingivalis outer membrane vesicles (OMVs).

DESIGN

OMVs were prepared fromP. gingivalis OMZ314 and used to stimulate human gingival epithelial (HGE) cells. The effects of curcumin on cellular expression of inflammatory cytokines were evaluated using real-time reverse transcription-polymerase chain reaction assays, while those on cellular migration were examined with a scratch wound assay. Furthermore, HGE cells were incubated with OMVs in the presence or absence of curcumin, then intracellular invasion by OMVs was observed with confocal laser scanning microscopy. Also, the effects of curcumin on cellular apoptotic death was examined.

RESULTS

Gene expressions of IL-6, IL-1β, and TNF-α in HGE cells stimulated with OMVs were significantly suppressed by curcumin in a dose-dependent manner, with suppressed protein production also noted. Moreover, curcumin inhibited the cytotoxic effects of OMVs on cellular migration. Finally, curcumin inhibited OMV adherence to and entry of cells, as well as cellular apoptotic death in a dose-dependent manner.

CONCLUSIONS

Curcumin showed marked inhibitory effects against the cytotoxic actions of P. gingivalis OMVs, indicating possible potency for preventing periodontal disease.

Photosensitizers attenuate LPS-induced inflammation: implications in dentistry and general health

Antimicrobial photodynamic therapy (aPDT) is a complementary therapeutic modality for periodontal and endodontic diseases, in which Gram-negative bacteria are directly involved. Currently, there are few evidences regarding the effects of aPDT on bacterial components such as lipopolysaccharide (LPS) and it would represent a major step forward in the clinical use of this therapy. In this context, this study aimed to evaluate the efficacy of different photosensitizers (PSs) used in aPDT in LPS inhibition. Four PSs were used in this study: methylene blue (MB), toluidine blue (TBO), new methylene blue (NMB), and curcumin (CUR). Different approaches to evaluate LPS interaction with PSs were used, such as spectrophotometry, Limulus amebocyte lysate (LAL) test, functional assays using mouse macrophages, and an in vivo model of LPS injection. Spectrophotometry showed that LPS decreased the absorbance of all PSs used, indicating interactions between the two species. LAL assay revealed significant differences in LPS concentrations upon pre-incubation with the different PSs. Interestingly, the inflammatory potential of LPS decreased after previous treatment with the four PSs, resulting in decreased secretion of inflammatory cytokines by macrophages. In vivo, pre-incubating curcumin with LPS prevented animals from undergoing septic shock within the established time. Using relevant models to study the inflammatory activity of LPS, we found that all PSs used in this work decreased LPS-induced inflammation, with a more striking effect observed for NMB and curcumin. These data advance the understanding of the mechanisms of LPS inhibition by PSs.

The implication of the PD-1/PD-L1 checkpoint in chronic periodontitis suggests novel therapeutic opportunities with natural products

An analysis of the implication of the PD-1/PD-L1 immune checkpoint in periodontitis is provided with the objective to propose a novel therapeutic approach. An exhaustive survey of the literature has been performed to answer two questions: (1) Is there a role for PD-1 and/or PD-L1 in the development of periodontitis? (2) Which natural products interfere with the checkpoint activity and show activity against periodontitis? All online published information was collected and analyzed. The pathogenic bacteria Porphyromonas gingivalis, through its membrane-attached peptidoglycans, exploits the PD-1/PD-L1 checkpoint to evade immune response and to amplify the infection. Three anti-inflammatory natural products (and derivatives or plant extracts) active against periodontitis and able to interfere with the checkpoint were identified. Both curcumin and baicalin attenuate periodontitis and induce a down-regulation of PD-L1 in cells. The terpenoid saponin platycodin D inhibits the growth of P. gingivalis responsible for periodontitis and shows a rare capacity to induce the extracellular release of a soluble form of PD-L1, thereby restoring T cell activation. A potential PD-L1 shedding mechanism is discussed. The targeting of the PD-1/PD-L1 immune checkpoint could be considered a suitable approach to improve the treatment of chronic periodontitis. The plant natural products curcumin, baicalin and platycodin D should be further evaluated as PD-1/PD-L1 checkpoint modulators active against periodontitis.

Local application of curcumin-loaded nanoparticles as an adjunct to scaling and root planing in periodontitis: Randomized, placebo-controlled, double-blind split-mouth clinical trial

OBJECTIVE

Assess a single local application of curcumin-loaded nanoparticles as an adjunct to scaling and root planing (SRP) in nonsurgical periodontal treatment (NPT).

MATERIALS AND METHODS

Twenty healthy subjects with periodontitis received SRP+PLGA/PLA nanoparticles loaded with 50 μg of curcumin (N-Curc) or SRP+empty nanoparticles. Probing pocket depth (PPD), clinical attachment level (CAL), and bleeding on probing (BOP) were monitored at baseline, 30, 90, and 180 days. IL-1α, IL-6, TNFα, and IL-10 in the gingival crevicular fluid (GCF) were assessed by ELISA, and counts of 40 bacterial species were determined by DNA hybridization at baseline, 3, 7, and 15 days post-therapy.

RESULTS

PPD, CAL, and BOP were similarly and significantly improved in both experimental groups. There was no difference in GCF cytokine levels between experimental groups, although IL-6 was decreased at 3 days only in the N-Curc group. NPT reduced counts of red complex bacterial species in both groups. Veillonella Parvula counts increased significantly only in N-Curc group at 7 days, whereas Aggregatibacter actinomycetemcomitans counts increased significantly only in the control group from day 3 to day 15.

CONCLUSION

We conclude that a single local administration of nanoencapsulated curcumin in periodontally diseased sites had no additive benefits to NPT.

CLINICAL RELEVANCE

Our results showed that a single local application of curcumin-loaded nanoparticles associated with nonsurgical periodontal therapy did not improve clinical outcomes. Hence, our findings do not support the use of curcumin as an adjunct to nonsurgical periodontal therapy.

Therapeutic effects of antibiotics loaded cellulose nanofiber and κ-carrageenan oligosaccharide composite hydrogels for periodontitis treatment

Periodontitis is an inflammatory disease that can lead to the periodontal pocket formation and tooth loss. This study was aimed to develop antimicrobials loaded hydrogels composed of cellulose nanofibers (CNF) and κ-carrageenan oligosaccharides (CO) nanoparticles for the treatment of periodontitis. Two antimicrobial agents such as surfactin and Herbmedotcin were selected as the therapeutic agents and the hydrogels were formulated based on the increasing concentration of surfactin. The proposed material has high thermal stability, controlled release, and water absorption capacity. This study was proceeded by investigating the in vitro antibacterial and anti-inflammatory properties of the hydrogels. This material has strong antibacterial activity against periodontal pathogens such as Streptococcus mutans, Porphyromonas gingivalis, Fusobacterium nucleatum, and Pseudomonas aeruginosa. Moreover, a significant increase in malondialdehyde (MDA) production and a decrease in biofilm formation and metabolic activity of the bacteria was observed in the presence of hydrogel. Besides, it reduced the reactive oxygen species (ROS) generation, transcription factor, and cytokines production in human gingival fibroblast cells (HGF) under inflammatory conditions. In conclusion, the hydrogels were successfully developed and proven to have antibacterial and anti-inflammatory properties for the treatment of periodontitis. Thus, it can be used as an excellent candidate for periodontitis treatment.

Interleukin-1β is a potential therapeutic target for periodontitis: a narrative review

Interleukin(IL)-1β, a pro-inflammatory cytokine, was elevated and participates in periodontitis. Not only the link between IL-1β and periodontitis was proved by clinical evidence, but also the increased IL-1β triggers a series of inflammatory reactions and promotes bone resorption. Currently, IL-1β blockage has been therapeutic strategies for autoimmune and autoinflammatory diseases such as rheumatoid arthritis, cryopyrin-associated periodic syndromes, gout and type II diabetes mellitus. It is speculated that IL-1β be a potential therapeutic target for periodontitis. The review focuses on the production, mechanism, present treatments and future potential strategies for IL-1β in periodontitis.

Activation of PERK in ET-1- and thrombin-induced pulmonary fibroblast differentiation: Inhibitory effects of curcumin

In the present study, we investigated the role of PKR-like endoplasmic reticular kinase (PERK), an endoplasmic reticulum (ER) stress kinase, in endothelin 1 (ET-1)- and thrombin-induced pulmonary fibrosis (PF), and the preventive effects of curcumin (CUR). Using the human embryonic WI-38 lung fibroblast cell line, ET-1 and thrombin induced the expression of ER stress-related proteins (CCAAT-enhancer-binding protein homologous protein, PERK, and binding immunoglobulin protein), a profibrogenic factor (cellular communication network factor 2 [CCN2]), and differentiation markers including α-smooth muscle actin (α-SMA), collagen I (Col I), and Col IV. Knockdown of PERK expression via small interfering RNA (siRNA) significantly reduced the increases in CCN2, α-SMA, Col I, and Col IV proteins in WI-38 cells according to western blot analysis and immunohistochemistry (IHC). Activation of c-Jun N-terminal kinase (JNK) was observed in ET-1- and thrombin-treated WI-38 cells, and the addition of a JNK inhibitor (SP) suppressed the induction of the indicated proteins by ET-1 and thrombin. Thapsigargin (TG), an ER stress inducer, elevated expressions of PERK and ER stress-related proteins with increased differentiation of WI-38 cells. Knockdown of PERK by siRNA or the PERK inhibitor glycogen synthesis kinase reduced expressions of the differentiation markers, α-SMA and Col IV, in WI-38 cells. CUR concentration-dependently inhibited ET-1- or thrombin-induced CCN2, α-SMA, and vimentin proteins with decreased levels of phosphorylated mitogen-activated protein kinase and PERK in WI-38 cells. An in vivo bleomycin-induced PF study showed that an intraperitoneal injection of CUR (30 mg/kg) reduced expressions of α-SMA, CCN2, Col IV, and vimentin in lung tissues via IHC staining using specific antibodies. This study is the first to demonstrate that PERK activation contributes to pulmonary fibroblast differentiation elicited by ET-1 or thrombin, and the inhibitory activity of CUR against PF is demonstrated herein.

Curcumin/Liposome Nanotechnology as Delivery Platform for Anti-inflammatory Activities via NFkB/ERK/pERK Pathway in Human Dental Pulp Treated With 2-HydroxyEthyl MethAcrylate (HEMA)

Curcumin, primary component of the spice turmeric extracted from the rhizomes of Curcuma longa, represents the major anti-oxidant and anti-inflammatory substance found in turmeric, acting thought various mechanisms not completely understood. Curcumin modulates cytokines, growth factors, transcription factors, inflammatory molecules and cell signaling pathways. During restorative dentistry practice, free resin monomers of 2-hydroxyethyl methacrylate (HEMA) propagate through dentin micro-channel and pulp into the bloodstream affecting cellular integrity. The study highlights the significance of application of curcumin bioactive component into liposomal formulations (CurLIP) to restore the homeostasis of dental pulp stem cells (hDPSCs) in response to 3 and 5 mmol L^–1 HEMA treatment. Cell proliferation in combination with changes of the morphological features, proinflammatory cytokines secretion as Interleukin (IL) 6, IL8, Monocyte Chemoattractant Protein-1 (MCP1) and Interferon-gamma (IFNγ) were assayed along with the nuclear factor (NF)-kB, an inducible transcription factor involved in the activation of several cell processes associated to extracellular signal-regulated kinases (ERK) and posphorylated (p-) ERK pathway. Our results showed a decreased cell proliferation, morphological changes and upregulation of IL6, IL8, MCP1 and IFNγ in presence of 3 and 5 mmol L^–1 HEMA treatment. CurLIP therapy in hDPSCs provokes an increase in cell proliferation and the block of inflammatory cytokines secretion through the inhibitory regulation of NFkB/ERK and pERK signaling cascade. The natural nanocarrier CurLIP influences numerous biochemical and molecular cascades causing anti-inflammatory properties in response to HEMA treatment in human dental pulp stem cells, representing an innovative endodontic formulation able to improve the quality of dental care with a major human community impact.