Effect of Curcumin on Systemic T Helper 17 Cell Response; Gingival Expressions of Interleukin-17 and Retinoic Acid Receptor-Related Orphan Receptor γt; and Alveolar Bone Loss in Experimental Periodontitis

Ulcerative colitis: molecular insights and intervention therapy

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by abdominal pain, diarrhea, rectal bleeding, and weight loss. The pathogenesis and treatment of UC remain key areas of research interest. Various factors, including genetic predisposition, immune dysregulation, and alterations in the gut microbiota, are believed to contribute to the pathogenesis of UC. Current treatments for UC include 5-aminosalicylic acids, corticosteroids, immunosuppressants, and biologics. However, study reported that the one-year clinical remission rate is only around 40%. It is necessary to prompt the exploration of new treatment modalities. Biologic therapies, such as anti-TNF-α monoclonal antibody and JAK inhibitor, primarily consist of small molecules targeting specific pathways, effectively inducing and maintaining remission. Given the significant role of the gut microbiota, research into intestinal microecologics, such as probiotics and prebiotics, and fecal microbiota transplantation (FMT) shows promising potential in UC treatment. Additionally, medicinal herbs, such as chili pepper and turmeric, used in complementary therapy have shown promising results in UC management. This article reviews recent findings on the mechanisms of UC, including genetic susceptibility, immune cell dynamics and cytokine regulation, and gut microbiota alterations. It also discusses current applications of biologic therapy, herbal therapy, microecologics, and FMT, along with their prospects and challenges.

Immunomodulatory Therapeutic Effects of Curcumin on M1/M2 Macrophage Polarization in Inflammatory Diseases

BACKGROUND

Due to their plasticity, macrophages exert critical effects on both promoting and suppressing inflammatory processes. Pathologic inflammatory conditions are frequently correlated with dynamic alterations in macrophage activation, with classically activated M1 cells associated with the promotion and maintenance of inflammation and M2 cells being linked to the resolution or smouldering of chronic inflammation. Inflammation deputes a common feature of various chronic diseases and the direct involvement in the insurgence and development of these conditions. Macrophages participate in an autoregulatory loop characterizing the inflammatory process, as they produce a wide range of biologically active mediators that exert either deleterious or beneficial effects during the inflammation. Therefore, balancing the favorable ratios of M1/M2 macrophages can help ameliorate the inflammatory landscape of pathologic conditions. Curcumin is a component of turmeric with many pharmacological properties.

OBJECTIVE

Recent results from both in-vivo and in-vitro studies have indicated that curcumin can affect polarization and/or functions of macrophage subsets in the context of inflammation-related diseases. There is no comprehensive review of the impact of curcumin on cytokines involved in macrophage polarization in the context of inflammatory diseases. The present review will cover some efforts to explore the underlying molecular mechanisms by which curcumin modulates the macrophage polarization in distant pathological inflammatory conditions, such as cancer, autoimmunity, renal inflammation, stroke, atherosclerosis, and macrophage-driven pathogenesis.

RESULTS

The accumulation of the findings from in vitro and in vivo experimental studies suggests that curcumin beneficially influences M1 and M2 macrophages in a variety of inflammatory diseases with unfavorable macrophage activation.

CONCLUSION

Curcumin not only enhances anti-tumor immunity (via shifting M polarization towards M1 phenotype and/or up-regulation of M1 markers expression) but ameliorates inflammatory diseases, including autoimmune diseases (experimental autoimmune myocarditis and Behcet's disease), nephropathy, chronic serum sickness, stroke, and atherosclerosis.

Unravelling the Therapeutic Potential of Nano-Delivered Functional Foods in Chronic Respiratory Diseases

Chronic inflammation of the respiratory tract is one of the most concerning public health issues, as it can lead to chronic respiratory diseases (CRDs), some of which are more detrimental than others. Chronic respiratory diseases include chronic obstructive pulmonary disease (COPD), asthma, lung cancer, and pulmonary fibrosis. The conventional drug therapies for the management and treatment of CRDs only address the symptoms and fail to reverse or recover the chronic-inflammation-mediated structural and functional damage of the respiratory tract. In addition, the low efficacy and adverse effects of these drugs have directed the attention of researchers towards nutraceuticals in search of potential treatment strategies that can not only ameliorate CRD symptoms but also can repair and reverse inflammatory damage. Hence, there is a growing interest toward investigating the medicinal benefits of nutraceuticals, such as rutin, curcumin, zerumbone, and others. Nutraceuticals carry many nutritional and therapeutic properties, including anti-inflammatory, antioxidant, anticancer, antidiabetic, and anti-obesity properties, and usually do not have as many adverse effects, as they are naturally sourced. Recently, the use of nanoparticles has also been increasingly studied for the nano drug delivery of these nutraceuticals. The discrete size of nanoparticles holds great potential for the level of permeability that can be achieved when transporting these nutraceutical compounds. This review is aimed to provide an understanding of the use of nutraceuticals in combination with nanoparticles against CRDs and their mechanisms involved in slowing down or reversing the progression of CRDs by inhibiting pro-inflammatory signaling pathways.

Nano-curcumin supplementation in critically ill patients with sepsis: a randomized clinical trial investigating the inflammatory biomarkers, oxidative stress indices, endothelial function, clinical outcomes and nutritional status

Sepsis is a severe reaction and excessive immune response to infection, which can lead to organ dysfunction, and death. This study aimed to investigate the protective effect of nano-curcumin (NC) on inflammatory biomarkers, endothelial function, oxidative stress indices, biochemical factors, nutritional status, and clinical outcomes in patients with sepsis. In the present double-blind placebo-controlled randomized clinical trial, 40 ICU-admitted patients were randomly allocated into either NC or placebo group for 10 days. Both nano-curcumin (160 mg) and placebo were administered via a nasogastric tube twice a day. The mRNA expression of nuclear-related factor 2 (Nrf-2), BCL2 associated X (BAX), B-cell lymphoma 2 (BCL-2), and toll-like receptor 4 (TLR-4) genes in the peripheral blood mononuclear cells (PBMCs), and the serum levels of primary, secondary, tertiary, and exploratory outcomes were assessed before the baseline and on days 5 and 10. There were significant improvements in the primary outcomes, including inflammatory markers (IL-6, IL-18, IL-1β, IL-10, TLR-4, BCL-2 and BAX), markers of endothelial function (ICAM-1 and VCAM-1), and oxidative stress indices (malondialdehyde (MDA), nuclear-related factor 2 (Nrf-2), catalase, superoxide dismutase (SOD), and TAC) (p < 0.005) in the NC group compared to the placebo group after 10 days, while no significant increase was observed in the glutathione peroxidase (GPx) level between the two groups. However, no significant decrease was observed in the levels of secondary outcomes, including biochemical factors (creatinine, fasting blood sugar (FBS), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), total bilirubin, triglycerides (TG) and total cholesterol (TC)) (P > 0.05). Our results showed that in the tertiary outcome (nutritional status), there was no significant increase (P > 0.05) except for TLC (P = 0.003). NC supplementation also resulted in a significant decrease in the exploratory outcomes including the SOFA score and the duration of mechanical ventilation (P < 0.05). Supplementation with NC may be a promising treatment strategy for critically ill patients with sepsis. However, further experiments are suggested to investigate the effects of nano-curcumin on biochemical pathways involved in sepsis.

Curcumin: Useful add-on for Rheumatic Diseases?

Plant-derived nutraceuticals are proposed as new key instruments to represent a profound "back to basics" shift in medical treatment. Data accumulated over the past ten years suggest that curcumin, the major active compound of the turmeric plant, has anti-inflammatory properties. It has yet to be determined whether the anti-inflammatory profile of curcumin is potent enough to justify the application of this substance as a nutritional supplement for patients with rheumatic diseases. To address this question, the most relevant in vitro studies that investigate the mechanism of action of curcumin were reviewed in this article. In addition, a total of 18 animal and human trials were evaluated. The pleiotropic, anti-inflammatory and immunomodulatory effects of curcumin were observed in animal studies. In addition, human trials demonstrated promising findings. In these studies, curcumin was able to reduce the expression of proinflammatory cytokines, lower the level of the C-reactive protein and improve clinical parameters. A limiting factor of the application of curcumin is the inconsistent bioavailability of the substance. Therefore, new formulations have been developed to improve the pharmacodynamic profile of curcumin. The future acceptance of the substance is dependent on new controlled clinical trials with a standardised formulation of curcumin administered as well as standard of care.

Immunopathogenesis and distinct role of Th17 in Periodontitis: A review

BACKGROUND

Periodontitis is a multifactorial inflammatory disease mediated by the host immune response to dental plaque. Periodontitis is characterized by periodontal bone loss and loss of tooth support. Several studies have corroborated the infiltration of T lymphocytes in periodontitis and correlated the infiltration with chronic inflammation in a dysregulated T cell-mediated immune response. The complexity of the disease has prompted multiple studies aiming to understand T cell-mediated pathogenesis.

HIGHLIGHT

Recent findings have demonstrated the pivotal role of helper T cells in many autoimmune diseases, such as rheumatoid arthritis, which has been conventionally correlated with periodontal bone loss. In contrast, the roles of helper T subsets, Th1, Th2, and particularly Th17, have not been explored. Th17-mediated pathogenesis is a significant aspect of the progression and therapy of periodontitis.

CONCLUSION

In this review, we highlight the complex role of Th17 in the underlying pro-inflammatory cascades mediated by a repertoire of Th17-released molecules and their role in aggravated inflammation in periodontitis. We also summarize recent therapeutics targeting Th17 and related molecules, primarily to ameliorate inflammation and maintain periodontal care.

Lipopolysaccharide-Preconditioned Dental Follicle Stem Cells Derived Small Extracellular Vesicles Treating Periodontitis via Reactive Oxygen Species/Mitogen-Activated Protein Kinase Signaling-Mediated Antioxidant Effect

Purpose

Lipopolysaccharide (LPS) pretreatment can enhance the therapeutic effect of dental follicle stem cells-derived small extracellular vesicles (DFC-sEV) for periodontitis, and this study aimed to investigate the underlying mechanisms and clinical application Of LPS-preconditioned DFC-sEV in periodontitis.

Methods

The protein spectrum of DFC-sEV before and after LPS pretreatment was determined by liquid chromatography-tandem mass spectrometry and bioinformatic analysis. Their effects on inflammatory periodontal ligament stem cells (PDLSCs) and macrophages were investigated for cell proliferation, migration, type 2 macrophage (M2) polarization, and intracellular reactive oxygen species (ROS) levels separately. In addition, the regulation of ROS/Jun amino-terminal kinases (JNK) and ROS/extracellular signal-related kinases (ERK) signaling by LPS-preconditioned DFC-sEV was also studied to reveal the antioxidant mechanism. In vivo, two kinds of DFC-sEV loaded with 0.2% hyaluronic acid (HA) gel were applied for canine periodontitis to evaluate the therapeutic potential.

Results

The proteomic analysis showed that thirty-eight proteins were differentially expressed in LPS-preconditioned DFC-sEV, and interestingly, the highly expressed proteins were mainly involved in antioxidant and enzyme-regulating activities. In addition to promoting PDLSCs and macrophage proliferation, LPS-preconditioned DFC-sEV inhibited intracellular ROS as an antioxidant. It reduced the RANKL/OPG ratio of PDLSCs by inhibiting ROS/JNK signaling under inflammatory conditions and promoted macrophages to polarize toward the M2 phenotype via ROS/ERK signaling. Furthermore, LPS-preconditioned DFC-sEV loaded with the HA injectable system could sustainably release sEV and enhance the therapeutic efficacy for periodontitis in canines.

Conclusion

LPS-preconditioned DFC-sEV could be effectively used as an auxiliary method for periodontitis treatment via antioxidant effects in a subgingival environment, and loading it with HA is feasible and effective for clinical applications.

Effects of nanocurcumin supplementation on T-helper 17 cells inflammatory response in patients with Behcet's disease: a randomized controlled trial

OBJECTIVE

Present research was performed to assess the effects of nanocurcumin supplementation on T-helper 17 (Th17) cells inflammatory response in patients with Behcet's disease (BD).

METHODS

In this randomized double-blind, placebo-controlled trial, 36 BD subjects were randomly placed into two groups to take 80 mg/day nanocurcumin or placebo for eight weeks. Disease activity, frequency of Th17 cells and expression of related parameters including retinoic acid-related orphan receptor γ (RORγt) transcription factor messenger RNA (mRNA), related microRNAs (miRNAs) such as miRNA-155, miRNA-181, and miRNA-326 as well as proinflammatory cytokines including interleukin (IL)-17 and IL-23 were evaluated.

RESULTS

Thirty-two patients (17 in the nanocurcumin and 15 in the placebo groups) completed the trial. Number of Th17 cells decreased significantly in the nanocurcumin group compared to baseline (p = .012) and placebo (p = .047). Moreover, RORγt, IL-17, IL-23, miRNA-155, miRNA-181, and miRNA-326 mRNA expression decreased significantly in the nanocurcumin group compared with baseline (p = .004, p = .009, p < .001, p < .001, p < .001, p < .001, respectively) and placebo (p = .002, p = .021, p = .006, p = .035, p < .001, p = .017, respectively). Significant reductions in IL-17 and IL-23 were seen in nanocurcumin group compared with baseline (p = .017 and p = .015) and placebo (p = .047 and p = .048, respectively). Significant reduction in disease activity was observed in nanocurcumin group compared with placebo group (p = .035).

CONCLUSION

Nanocurcumin supplementation had favorable effects in improving inflammatory factors and disease activity in BD patients. Additional studies are warranted to suggest nanocurcumin as a safe complementary therapy in BD.HighlightsNanocurcumin supplementation decreased Th17 cells frequency significantly compared with baseline and placebo group.Nanocurcumin supplementation decreased mRNA expression of RORγt, IL-17, IL-23, miRNA-155, miRNA-181, and miRNA-326 significantly compared to baseline and placebo group.Nanocurcumin supplementation decreased cell supernatant IL-17 and IL-23 significantly compared to baseline and placebo group.Nanocurcumin supplementation decreased disease activity significantly compared to placebo group.

Curcumin supplementation in pediatric patients: A systematic review of current clinical evidence

This systematic review was designed to determine the clinical efficacy and safety of curcumin supplementation for pediatric patients based on clinical trials in children. We systematically searched electronic databases including PubMed, EMBASE, Web of Science, and Scopus for all studies that investigated curcumin administration in the pediatric population without any time frame limitation. Finally, we identified 16 studies for this review. Clinical efficacy and safety of curcumin were assessed in children with inflammatory and immune disorders (including asthma, inflammatory bowel disease (IBD), and juvenile idiopathic arthritis (JIA)), metabolic disorders, autosomal dominant polycystic kidney disease (ADPKD), cystic fibrosis (CF), tetralogy of Fallot (TOF), and infectious diseases. Curcumin was administered in a wide range of doses (45 mg-4,000 mg daily) and durations (2-48 weeks). Overall, curcumin was well tolerated in all studies and improved the severity of inflammatory and immune disorders and metabolic diseases. However, more studies are needed to clarify the role of curcumin supplementation among children with ADPKD, CF, TOF, and infectious diseases. Because of substantial heterogeneity in methodological quality, design, outcomes, dose, duration of intake, formulations, and study populations across studies, no quantitative analysis was performed. Additional large-scale, randomized, placebo-controlled clinical trials are needed to confirm the results of the conducted studies.

Nanocurcumin supplementation ameliorates Behcet's disease by modulating regulatory T cells: A randomized, double-blind, placebo-controlled trial

Current research was designed to assess the effects of nanocurcumin supplementation on regulatory T (Treg) cells frequency and function in Behçet's disease (BD). In this randomized double-masked, placebo-controlled trial, 36 BD subjects were randomly put into two groups to take one 80 mg nanocurcumin capsule or placebo daily for 8 weeks. Before and after trial, disease activity, Treg cells frequency and expression of related immunologic parameters including forkhead box protein P3 (Foxp3) transcription factor messenger RNA (mRNA) and microRNAs (miRNAs) such as miRNA-25 and miRNA-106b as well as cytokines including transforming growth factor (TGF)-β and interleukin (IL)-10 were studied. Thirty-two patients (17 in the nanocurcumin and 15 in the placebo groups) completed the trial. Treg cells frequency increased significantly in the nanocurcumin group compared with baseline (P < 0.001) and placebo group (P < 0.001). Moreover, FoxP3, TGF-β, IL-10, miRNA-25, and miRNA-106b mRNA expression levels increased considerably in the nanocurcumin group compared to baseline (P < 0.001) and placebo group (P < 0.001, P < 0.001, P = 0.025, P = 0.011, and P < 0.001, respectively). Significant increases in serum TGF-β and IL-10 were seen in nanocurcumin group compared with baseline (P < 0.001) and placebo group (P = 0.001 and P < 0.001, respectively). Significant decrease in disease activity was found in nanocurcumin group compared with placebo group (P = 0.044). Our study provided a promising view for desirable effects of nanocurcumin supplementation in improving immunological parameters and disease activity in BD.

Th17 Cells in Periodontitis and Its Regulation by A20

Periodontitis is a prevalent chronic disease that results in loss of periodontal ligament and bone resorption. Triggered by pathogens and prolonged inflammation, periodontitis is modulated by the immune system, especially pro-inflammatory cells, such as T helper (Th) 17 cells. Originated from CD4⁺ Th cells, Th17 cells play a central role for they drive and regulate periodontal inflammation. Cytokines secreted by Th17 cells are also major players in the pathogenesis of periodontitis. Given the importance of Th17 cells, modulators of Th17 cells are of great clinical potential and worth of discussion. This review aims to provide an overview of the current understanding of the effect of Th17 cells on periodontitis, as well as a brief discussion of current and potential therapies targeting Th17 cells. Lastly, we highlight this article by summarizing the causal relationship between A20 (encoded by TNFAIP3), an anti-inflammatory molecule, and Th17 cell differentiation.

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.

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.

Curcumin Regulated the Homeostasis of Memory T Cell and Ameliorated Dextran Sulfate Sodium-Induced Experimental Colitis

Immune memory is protective against reinvasion by pathogens in the homeostatic state, while immune memory disorders can cause autoimmune disease, including inflammatory bowel disease. Curcumin is a natural compound shown to be effective against human inflammatory bowel disease and experimental colitis, but the underlying mechanism is unclear. Here, experimental colitis was induced by dextran sulfate sodium (DSS) in this study. Significant changes in the percentages of naïve, central memory T (TCM), and effector memory (TEM) cells and their CD4⁺ and CD8⁺ subsets were found in the peripheral blood of mice with colitis using flow cytometry. After 7 days of continuous curcumin (100 mg/kg/day) administration, the DSS-induced experimental colitis was effectively relieved, with significant decreases in the ratio of day weight to initial body weight, colonic weight, pathological injury score, levels of proinflammatory cytokines IL-7, IL-15, and IL-21, colonic mucosal ulceration, and amount of inflammatory infiltrate. Importantly, curcumin significantly restored the percentages of naïve, TCM, and TEM cells and their CD4⁺ and CD8⁺ subpopulations. In addition, curcumin significantly inhibited the activation of the JAK1/STAT5 signaling pathway, downregulation of JAK1, STAT5, and p-STAT5 proteins in colon tissue, and upregulation of PIAS1 proteins. These results suggested that curcumin effectively regulated the differentiation of naïve, TCM, and TEM cells in the peripheral blood to alleviate DSS-induced experimental colitis, which might be related to the inhibition of JAK1/STAT5 signaling activity.

Periodontitis is an inflammatory disease of oxidative stress: We should treat it that way

Periodontitis is a highly prevalent disease. As it progresses, it causes serious morbidity in the form of periodontal abscesses and tooth loss and, in the latter stages, pain. It is also now known that periodontitis is strongly associated with several nonoral diseases. Thus, patients with periodontitis are at greater risk for the development and/or exacerbation of diabetes, chronic obstructive pulmonary disease, and cardiovascular diseases, among other conditions. Although it is without question that specific groups of oral bacteria which populate dental plaque play a causative role in the development of periodontitis, it is now thought that once this disease has been triggered, other factors play an equal, and possibly more important, role in its progression, particularly in severe cases or in cases that prove difficult to treat. In this regard, we allude to the host response, specifically the notion that the host, once infected with oral periodontal pathogenic bacteria, will mount a defense response mediated largely through the innate immune system. The most abundant cell type of the innate immune system - polymorphonuclear neutrophils - can, when protecting the host from microbial invasion, mount a response that includes upregulation of proinflammatory cytokines, matrix metalloproteinases, and reactive oxygen species, all of which then contribute to the tissue damage and loss of teeth commonly associated with periodontitis. Of the mechanisms referred to here, we suggest that upregulation of reactive oxygen species might play one of the most important roles in the establishment and progression of periodontitis (as well as in other diseases of inflammation) through the development of oxidative stress. In this overview, we discuss both innate and epigenetic factors (eg, diabetes, smoking) that lead to the development of oxidative stress. This oxidative stress then provides an environment conducive to the destructive processes observed in periodontitis. Therefore, we shall describe some of the fundamental characteristics of oxidative stress and its effects on the periodontium, discuss the diseases and other factors that cause oxidative stress, and, finally, review potentially novel therapeutic approaches for the management (and possibly even the reversal) of periodontitis, which rely on the use of therapies, such as resveratrol and other antioxidants, that provide increased antioxidant activity in the host.

Positive effect of curcumin on experimental peridontitis via suppression of IL-1-beta and IL-6 expression level

This study examined the effect of curcumin on T-helper (Th17) and T-regulatory (Treg) cells regarding the mRNA of cytokines/mediators in the gingiva. Thirty-five male albino Wistar rats were divided into four groups: Group 1: periodontitis (n = 9); Group 2: periodontitis with curcumin treatment (n = 8); Group 3: periodontally healthy with curcumin treatment (n = 10); and Group 4: periodontally healthy (n = 8). Curcumin was administered via oral gavage (30 mg/kg/day) for a total of 15 days. The gingival tissues were investigated regarding mRNA expressions of Th17/Treg cytokines with qRT-PCR. The distributional properties of the data were evaluated using the Anderson-Darling normality test. Kruskal-Wallis and Mann-Whitney U tests were employed for multiple group comparisons. Partial least squares regression discriminant analysis (PLS-DA) was used to evaluate the degree of contribution of each mRNA to the separation of treatment groups. When the periodontitis groups were compared, curcumin treatment resulted in lower IL-1β (Group 2 median: 0.002, Group 1 median: 0.12) and IL-6 (Group 2 median: 0.031, Group 1 median: 0.078) and higher IL-17 (Group 2 median: 1.07, Group 1 median: 0.583) relative mRNA expression in Group 2 than in Group 1 (p < 0.001). Group 3 also had higher IL-10 relative expression (median: 0.067) than Groups 1 and 4 (median: 0.028, 0.007, respectively. p < 0.001). These results indicate that curcumin might be a promising agent for the prevention and/or treatment of periodontal diseases due to its decreasing effect on IL-1β and IL-6 mRNA expression.

IL-10 Dampens an IL-17-Mediated Periodontitis-Associated Inflammatory Network

Emerging evidence suggests comprehensive immune profiling represents a highly promising, yet insufficiently tapped approach to identify potentially prognostic signatures for periodontitis. In this report, we agnostically identified a periodontitis-associated inflammatory expression network with multiple biomarkers identified within gingival crevicular fluid samples from study participants by applying principal component analysis. We identified an IL-17-dominated trait that is associated with periodontal disease and is inversely modified by the level of IL-10. IL-10 mitigated chemokine CXCL5 and CXCL1 expressions in IL-17-stimulated peripheral blood monocytic cells and peripheral blood monocytic cell-derived macrophages. Il10-deficient mice presented more bone loss, which was associated with more Il17 and IL-17-mediated chemokine and cytokine expression at the transcriptional levels in comparison with control wild-type mice in both the Porphyromonas gingivalis-induced experimental murine periodontitis and ligature-induced alveolar bone-loss models. The dampening effect of IL-10 on the excessive signaling of IL-17 appeared to be mediated by innate immune cells populations rather than by gingival epithelial cells, which are the major cell target for IL-17 signaling. Additionally, elevated IL-17 response in Il10-deficient mice specifically elicited an M1-skewing macrophage phenotype in the gingiva that was associated with the advanced bone loss in the ligature model. In summary, IL-17 dominated an inflammatory network characteristic of periodontitis, and IL-10 dampens this excessive IL-17-mediated periodontitis trait.

Therapeutic effects of curcumin on sepsis and mechanisms of action: A systematic review of preclinical studies

Sepsis is a complex disease that begins with an infectious disorder and causes excessive immune responses. Curcumin is considered as an active component of turmeric that can improve the condition in sepsis due to its anti-inflammatory and antioxidant properties. PubMed, Embase, Google Scholar, Web of Science, and Scopus databases were searched. Searching was not limited to a specific publication period. Only English-language original articles, which had examined the effect of curcumin on sepsis, were included. At first, 1,098 articles were totally found, and 209 articles were selected after excluding duplicated data; 46 articles were remained due to the curcumin effects on sepsis. These included 23 in vitro studies and 23 animal studies. Our results showed that curcumin and various analogs of curcumin can have an inhibitory effect on sepsis-induced complications. Curcumin has the ability to inhibit the inflammatory, oxidative coagulation factors, and regulation of immune responses in sepsis. Despite the promising evidence of the therapeutic effects of curcumin on the sepsis complication, further studies seem necessary to investigate its effect and possible mechanisms of action in human studies.

An emerging role of interleukin-23 in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune, chronic inflammatory disease and is characterized by destruction of the articular cartilage. A number of pro-inflammatory cytokines work sequentially and in concert with one another to induce the development of RA. IL-23, a member of IL-12 family, is composed of p19 and p40 subunits and it interacts with IL-23 receptor complex to trigger plethora of biochemical actions. A number of preclinical studies have shown the role of IL-23 in the development of RA in rodents. IL-23 receptor signaling is primarily linked to the activation of JAK-STAT, tyrosine kinase 2, NF-kB, and retinoic acid receptor-related orphan receptors. IL-23 produces its osteoclastogenic effects, mainly through IL-17 and Th17 cells suggesting the importance of IL-23/IL-17/Th17 in the joint inflammation and destruction in RA. Monoclonal antibodies targeted against IL-23, including tildrakizumab and guselkumab have been developed and evaluated in clinical trials. However, there are very limited clinical studies regarding the use of IL-23 modulators in RA patients. The present review discusses the different aspects of IL-23 including its structural features, signal transduction pathway, preclinical, and clinical role in RA.

Curcumin and Intestinal Inflammatory Diseases: Molecular Mechanisms of Protection

Intestinal inflammatory diseases, such as Crohn’s disease, ulcerative colitis, and necrotizing enterocolitis, are becoming increasingly prevalent. While knowledge of the pathogenesis of these related diseases is currently incomplete, each of these conditions is thought to involve a dysfunctional, or overstated, host immunological response to both bacteria and dietary antigens, resulting in unchecked intestinal inflammation and, often, alterations in the intestinal microbiome. This inflammation can result in an impaired intestinal barrier allowing for bacterial translocation, potentially resulting in systemic inflammation and, in severe cases, sepsis. Chronic inflammation of this nature, in the case of inflammatory bowel disease, can even spur cancer growth in the longer-term. Recent research has indicated certain natural products with anti-inflammatory properties, such as curcumin, can help tame the inflammation involved in intestinal inflammatory diseases, thus improving intestinal barrier function, and potentially, clinical outcomes. In this review, we explore the potential therapeutic properties of curcumin on intestinal inflammatory diseases, including its antimicrobial and immunomodulatory properties, as well as its potential to alter the intestinal microbiome. Curcumin may play a significant role in intestinal inflammatory disease treatment in the future, particularly as an adjuvant therapy.

Enhanced efficacy of chemically modified curcumin in experimental periodontitis: systemic implications

Introduction

Dental microbial biofilm initiates gingival inflammation, and its suppression is the current dominant strategy for treating periodontitis. However, the host response to the biofilm is largely responsible for the connective tissue breakdown including alveolar bone loss, which is mediated by proinflammatory cytokines and matrix metalloproteinases (MMPs).

Methods

The current study compared the efficacy of a novel host-modulation compound, a chemically modified curcumin (CMC 2.24), to that of its parent compound (natural curcumin), in both lipopolysaccharide (LPS) (a bacterial endotoxin)-induced cell culture and in vivo models of periodontitis.

Results

In cell culture, both CMC 2.24 and curcumin appeared similarly effective in suppressing LPS-induced cytokine (IL-1β and TNF-α) secretion by mononuclear inflammatory cells; however, CMC 2.24 significantly reduced MMP-9 secretion by 78% (P<0.05) whereas curcumin was ineffective. In vivo, CMC 2.24 administration was more effective than curcumin in suppressing (a) IL-1β in gingival tissue and (b) MMP-9 in both gingiva and plasma, the latter indicating a reduced severity of systemic inflammation. The difference in primary clinical outcome between the two treatments was that CMC 2.24 reduced the pathologically excessive alveolar bone loss, assessed morphometrically at multiple sites, by 80%-90% (P<0.01), whereas curcumin, surprisingly, either increased (P<0.05) or had no effect on alveolar bone loss at these sites.

Conclusion

These data, plus that from previous studies, support the therapeutic potential of CMC 2.24 in the management of inflammatory periodontal disease and its ability to reduce the risk of associated systemic diseases. The current study also indicates that the MMP-9 inhibitor efficacy is associated with the ability of CMC 2.24 (but not curcumin) to inhibit alveolar bone loss in this rat model of periodontitis.

The pleiotropic role of interleukin-17 in atherosclerosis

Atherosclerosis is the main cause of cardiovascular diseases (CVDs), which considers the leading cause of mortality worldwide. Atherosclerosis is a chronic inflammatory condition of arterials' wall in which the development and the destabilization of plaque occur. Both innate and adaptive immunity play a significant role in modifying lipoproteins in arterials' wall. Recent investigations have demonstrated the opposing roles of CD4⁺ T cells subtypes in atherosclerosis. T helper-1 (Th1) response and pro-inflammatory cytokines possess proatherogenic effects, whereas T regulatory (Treg) cells have an atheroprotective role. Th17 cells have emerged as a new CD4⁺ T-cell subtype, which produce IL-17 that plays a crucial role in numerous inflammatory and autoimmune diseases. Recently, several studies have investigated the potential role of IL-17 in atherosclerosis. Some investigations have suggested a proatherogenic effect, however the others proposed an atheroprotective role. Hence, the exact role of IL-17 in the disease development and plaque stability is still debatable. In this review, we summarize the current knowledge on both atherogenesis and atheroprotective roles of IL-17. In addition, the synergistic and antagonistic effects of IL-17 with other cytokines in atherosclerosis will be discussed. On the basis of the current understanding of these roles, the possibility of developing novel therapeutic strategies against atherosclerosis may be evolved.

Curcumin for the Management of Periodontitis and Early ACPA-Positive Rheumatoid Arthritis: Killing Two Birds with One Stone

We propose curcumin as a preventive measure to avoid/manage periodontitis (PD), and as a natural immunosuppressant for rheumatoid arthritis (RA). PD, mainly caused by Porphyromonas gingivalis forming biofilm and leading to tooth decay, is a major public health issue and a risk factor for the development of RA in humans. P. gingivalis is able to trigger experimental autoimmune arthritis in animal models and in humans can induce citrullinated peptides, which not only are a source of anti-citrullinated antibodies (ACPAs), but also participate in autoreactive responses and disease development. Curcumin appears to have efficient anti-bacterial activity against P. gingivalis infection and biofilm formation. In addition to antibacterial, anti-oxidant, and anti-inflammatory action, curcumin exerts unique immunosuppressant properties via the inhibition of Th17 pro-inflammatory responses and promotion of regulatory T cells, thus suppressing autoimmunity. We introduce curcumin as a natural product for the management of both PD and RA-related autoreactivity, possibly also as a preventive measure in early RA or individuals at high risk to develop RA.

Local administration of curcumin-loaded nanoparticles effectively inhibits inflammation and bone resorption associated with experimental periodontal disease

There is evidence indicating that curcumin has multiple biological activities, including anti-inflammatory properties. In vitro and in vivo studies demonstrate that curcumin may attenuate inflammation and the connective tissue destruction associated with periodontal disease. Most of these studies use systemic administration, and considering the site-specific nature of periodontal disease and also the poor pharmacodynamic properties of curcumin, we conducted this proof of principle study to assess the biological effect of the local administration of curcumin in a nanoparticle vehicle on experimental periodontal disease. We used 16 rats divided into two groups of 8 animals according to the induction of experimental periodontal disease by bilateral injections of LPS or of the vehicle control directly into the gingival tissues 3×/week for 4 weeks. The same volume of curcumin-loaded nanoparticles or of nanoparticle vehicle was injected into the same sites 2×/week. µCT analysis showed that local administration of curcumin resulted in a complete inhibition of inflammatory bone resorption and in a significant decrease of both osteoclast counts and of the inflammatory infiltrate; as well as a marked attenuation of p38 MAPK and NF-kB activation. We conclude that local administration of curcumin-loaded nanoparticles effectively inhibited inflammation and bone resorption associated with experimental periodontal disease.

Treponema denticola increases MMP-2 expression and activation in the periodontium via reversible DNA and histone modifications

Host-derived matrix metalloproteinases (MMPs) and bacterial proteases mediate destruction of extracellular matrices and supporting alveolar bone in periodontitis. The Treponema denticola dentilisin protease induces MMP-2 expression and activation in periodontal ligament (PDL) cells, and dentilisin-mediated activation of pro-MMP-2 is required for cellular fibronectin degradation. Here, we report that T. denticola regulates MMP-2 expression through epigenetic modifications in the periodontium. PDL cells were treated with epigenetic enzyme inhibitors before or after T. denticola challenge. Fibronectin fragmentation, MMP-2 expression, and activation were assessed by immunoblot, zymography, and qRT-PCR, respectively. Chromatin modification enzyme expression in T. denticola-challenged PDL cells and periodontal tissues were evaluated using gene arrays. Several classes of epigenetic enzymes showed significant alterations in transcription in diseased tissue and T. denticola-challenged PDL cells. T. denticola-mediated MMP-2 expression and activation were significantly reduced in PDL cells treated with inhibitors of aurora kinases and histone deacetylases. In contrast, DNA methyltransferase inhibitors had little effect, and inhibitors of histone acetyltransferases, methyltransferases, and demethylases exacerbated T. denticola-mediated MMP-2 expression and activation. Chronic epigenetic changes in periodontal tissues mediated by T. denticola or other oral microbes may contribute to the limited success of conventional treatment of chronic periodontitis and may be amenable to therapeutic reversal.

Curcumin: A natural modulator of immune cells in systemic lupus erythematosus

Curcumin is a polyphenol natural product isolated from turmeric, interacting with different cellular and molecular targets and, consequently, showing a wide range of pharmacological effects. Recent preclinical and clinical trials have revealed immunomodulatory properties of curcumin that arise from its effects on immune cells and mediators involved in the immune response, such as various T-lymphocyte subsets and dendritic cells, as well as different inflammatory cytokines. Systemic lupus erythematosus (SLE) is an inflammatory, chronic autoimmune-mediated disease characterized by the presence of autoantibodies, deposition of immune complexes in various organs, recruitment of autoreactive and inflammatory T cells, and excessive levels of plasma proinflammatory cytokines. The function and numbers of dendritic cells and T cell subsets, such as T helper 1 (Th1), Th17, and regulatory T cells have been found to be significantly altered in SLE. In the present report, we reviewed the results of in vitro, experimental (pre-clinical), and clinical studies pertaining to the modulatory effects that curcumin produces on the function and numbers of dendritic cells and T cell subsets, as well as relevant cytokines that participate in SLE.